Planning and Design
of Airports
Robert Horonjeff
Francis X. McKelvey
William J. Sproule
Seth B. Young
Fifth Edition
New York Chicago San Francisco
Lisbon London Madrid Mexico City
Milan New Delhi San Juan
Seoul Singapore Sydney Toronto
Copyright © 2010, 1994, 1983, 1975, 1962 by The McGraw-Hill Companies, Inc. All rights reserved.
Except as permitted under the United States Copyright Act of 1976, no part of this publication may be
reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without
the prior written permission of the publisher.
ISBN: 978-0-07-164255-2
MHID: 0-07-164255-2
The material in this eBook also appears in the print version of this title: ISBN: 978-0-07-144641-9,
MHID: 0-07-144641-9.
All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every
occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the
trademark owner, with no intention of infringement of the trademark. Where such designations appear in
this book, they have been printed with initial caps.
McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales
promotions, or for use in corporate training programs. To contact a representative please e-mail us at
bulksales@mcgraw-hill.com.
Information contained in this work has been obtained by The McGraw-Hill Companies, Inc.
(“McGraw-Hill”) from sources believed to be reliable. However, neither McGraw-Hill nor its authors
guarantee the accuracy or completeness of any information published herein, and neither McGraw-Hill nor
its authors shall be responsible for any errors, omissions, or damages arising out of use of this information.
This work is published with the understanding that McGraw-Hill and its authors are supplying information
but are not attempting to render engineering or other professional services. If such services are required, the
assistance of an appropriate professional should be sought.
TERMS OF USE
This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGrawHill”) and its
licensors reserve all rights in and to the work. Use of this work is subject to these terms. Except as
permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you
may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based
upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it without
McGraw-Hill’s prior consent. You may use the work for your own noncommercial and personal use; any
other use of the work is strictly prohibited. Your right to use the work may be terminated if you fail to
comply with these terms.
THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR
RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION
THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND
EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill and its licensors do not warrant or guarantee that the functions contained
in the work will meet your requirements or that its operation will be uninterrupted or error free. Neither
McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or
omission, regardless of cause, in the work or for any damages resulting therefrom. McGraw-Hill has no
responsibility for the content of any information accessed through the work. Under no circumstances shall
McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, unitive, consequential or similar
damages that result from the use of or inability to use the work, even if any of them has been advised of the
possibility of such damages. This limitation of liability shall apply to any claim or cause whatsoever whether
such claim or cause arises in contract, tort or otherwise.
About the Authors
Robert Horonjeff (deceased) was an internationally
known consultant on airport design and professor of
transportation engineering at the University of
California, Berkeley.
Francis X. McKelvey (deceased) was a professor of
civil engineering at Michigan State University. He
served as a consultant on transportation and airport
planning to federal, state, and local agencies, as well as
to private firms in the United States and abroad.
William J. Sproule is a professor of civil and environmental engineering at Michigan Technological University.
He has many years of experience in government service,
consulting, and university teaching and research in
transportation planning, traffic engineering, airport
planning and design, and automated people movers in
Canada and the United States. He is active in several
professional societies and is the 2008 recipient of the
ASCE Robert Horonjeff Award for his work in airport
engineering.
Seth B. Young is an associate professor in the Department of Aviation at The Ohio State University and
president of the International Aviation Management
Group, Inc. He serves as a consultant and instructor to
airports around the world on issues of airport
management, planning, and design. Dr. Young is the
chair of the National Academies Transportation Research
Board Committee on Aviation System Planning. He is a
certified member of the American Association of Airport
Executives, a licensed airplane and seaplane commercial
pilot, and a certified flight instructor.
This page intentionally left blank
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Part 1 Airport Planning
1
The Nature of Civil Aviation and Airports . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commercial Service Aviation . . . . . . . . . . . . . . . . . . .
Passenger Air Carriers . . . . . . . . . . . . . . . . . . .
International Air Transportation . . . . . . . . . .
Air Cargo
.............................
General Aviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Civil Aviation Airports . . . . . . . . . . . . . . . . . . . . . . . .
Historical Review of the Legislative Role
in Aviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Commerce Act of 1926 . . . . . . . . . . . . . . .
Civil Aeronautics Act of 1938 . . . . . . . . . . . . .
Federal Airport Act of 1946 . . . . . . . . . . . . . . .
Federal Aviation Act of 1958 . . . . . . . . . . . . . .
Creation of the U.S. Department
of Transportation . . . . . . . . . . . . . . . . . . . . .
Airport and Airway Development Act
of 1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Airline Deregulation Act of 1978 . . . . . . . . . .
Impact of Airline Deregulation . . . . . . . . . . . .
The Airport and Airway Improvement Act
of 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Aviation Safety and Capacity Act
of 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AIR-21: The Wendell Ford Aviation
Investment Act for the 21st Century . . . . . . . .
The Aviation and Transportation Security
Act of 2001 . . . . . . . . . . . . . . . . . . . . . . . . . .
Vision 100 Century of Aviation
Act of 2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NextGen Financing Reform Act of 2007/
FAA Reauthorization Act of 2009 . . . . . . .
State Roles in Aviation and Airports . . . . . . . . . . . . .
3
3
4
7
7
8
10
11
17
17
18
21
24
26
27
31
32
33
33
34
34
35
35
36
v
vi
Contents
Aviation Organizations and Their Functions . . . . . .
Federal Agencies of the United States
Government . . . . . . . . . . . . . . . . . . . . . . . . .
Federal Aviation Administration . . . . . . . . . .
Transportation Security Administration . . . .
Environmental Protection Agency . . . . . . . . .
National Transportation Safety Board . . . . . .
State Agencies . . . . . . . . . . . . . . . . . . . . . . . . . .
The International Civil Aviation
Organization . . . . . . . . . . . . . . . . . . . . . . . . .
Industry and Trade Organizations . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Web References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
3
Aircraft Characteristics Related
to Airport Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensional Standards . . . . . . . . . . . . . . . . . . . . . . . .
Landing Gear Configurations . . . . . . . . . . . . . . . . . . .
Aircraft Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Atmospheric Conditions Affecting
Aircraft Performance
.......................
Air Pressure and Temperature . . . . . . . . . . . .
Wind Speed and Direction . . . . . . . . . . . . . . .
Aircraft Performance Characteristics . . . . . . . . . . . .
Aircraft Speed
.........................
Payload and Range
.....................
Runway Performance . . . . . . . . . . . . . . . . . . .
Declared Distances . . . . . . . . . . . . . . . . . . . . . .
Wingtip Vortices . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Traffic Management . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A Brief History of Air Traffic Management . . . . . . .
The Organizational Hierarchy of Air Traffic
Management in the United States . . . . . . . . . . . . .
The Air Traffic Control System
Command Center . . . . . . . . . . . . . . . . . . . .
Air Route Traffic Control Centers . . . . . . . . .
Terminal Approach Control Facilities . . . . . .
Airport Traffic Control Tower . . . . . . . . . . . . .
Flight Service Stations . . . . . . . . . . . . . . . . . . .
Air Traffic Management Rules . . . . . . . . . . . . . . . . . .
37
37
37
42
42
43
43
44
45
46
47
49
57
59
61
63
69
70
73
75
75
77
79
82
89
90
95
95
96
97
97
97
98
99
100
100
Contents
Airspace Classifications and Airways . . . . . . . . . . . .
Airways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Colored Airways . . . . . . . . . . . . . . . . . . . . . . . .
Victor Airways . . . . . . . . . . . . . . . . . . . . . . . . .
Jet Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Area Navigation . . . . . . . . . . . . . . . . . . . . . . . .
Air Traffic Separation Rules . . . . . . . . . . . . . . . . . . . .
Vertical Separation in the Airspace . . . . . . . .
Assigned Flight Altitudes . . . . . . . . . . . . . . . .
Longitudinal Separation in the Airspace . . .
Lateral Separation in the Airspace . . . . . . . . .
Navigational Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ground-Based Systems . . . . . . . . . . . . . . . . . .
Satellite-Based Systems: Global
Positioning System . . . . . . . . . . . . . . . . . . .
The Modernization of Air Traffic Management . . . .
NextGen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SWIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NextGen Data Communications . . . . . . . . . .
NextGen Enabled Weather . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
101
106
107
108
108
108
110
111
111
111
113
114
114
4
Airport Planning Studies . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Types of Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Airport System Plan . . . . . . . . . . . . . . . . .
Airport Site Selection . . . . . . . . . . . . . . . . . . . .
The Airport Master Plan . . . . . . . . . . . . . . . . .
The Airport Project Plan . . . . . . . . . . . . . . . . .
Continuing Planning Process . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
133
133
135
135
137
138
141
146
147
5
Forecasting for Airport Planning . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Levels of Forecasting . . . . . . . . . . . . . . . . . . . . . . . . . .
Forecasting Methods . . . . . . . . . . . . . . . . . . . . . . . . . .
Time Series Method . . . . . . . . . . . . . . . . . . . . .
Market Share Method . . . . . . . . . . . . . . . . . . .
Econometric Modeling . . . . . . . . . . . . . . . . . . .
Forecasting Requirements and Applications . . . . . .
The Airport System Plan . . . . . . . . . . . . . . . . .
The Airport Master Plan . . . . . . . . . . . . . . . . .
The Future Aviation Forecasting Environment . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
149
149
151
152
154
156
158
162
164
164
168
169
124
127
129
129
130
130
130
vii
viii
Contents
Part 2 Airport Design
6
Geometric Design of the Airfield . . . . . . . . . . . . . . .
Airport Design Standards . . . . . . . . . . . . . . . . . . . . . .
Airport Classification . . . . . . . . . . . . . . . . . . . . . . . . . .
Utility Airports . . . . . . . . . . . . . . . . . . . . . . . . .
Transport Airports . . . . . . . . . . . . . . . . . . . . . .
Runways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway Configurations . . . . . . . . . . . . . . . . . . . . . . .
Single Runway . . . . . . . . . . . . . . . . . . . . . . . . .
Parallel Runways . . . . . . . . . . . . . . . . . . . . . . .
Intersecting Runways . . . . . . . . . . . . . . . . . . .
Open-V Runways . . . . . . . . . . . . . . . . . . . . . . .
Combinations of Runway Configurations . . . .
Runway Orientation
....................
The Wind Rose . . . . . . . . . . . . . . . . . . . . . . . . .
Estimating Runway Length . . . . . . . . . . . . . .
Runway System Geometric Specifications . . . .
Parallel Runway System Spacing . . . . . . . . . .
Sight Distance and Longitudinal Profile . . . .
Transverse Gradient . . . . . . . . . . . . . . . . . . . . .
Airfield Separation Requirements
Related to Runways . . . . . . . . . . . . . . . . . . .
Obstacle Clearance Requirements . . . . . . . . .
FAR Part 77 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ICAO Annex 14
........................
TERPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway End Siting Requirements . . . . . . . . .
Taxiways and Taxilanes . . . . . . . . . . . . . . . . . . . . . . . .
Widths and Slopes . . . . . . . . . . . . . . . . . . . . . .
Taxiway and Taxilane Separation
Requirements . . . . . . . . . . . . . . . . . . . . . . . .
Sight Distance and Longitudinal Profile . . . .
Exit Taxiway Geometry . . . . . . . . . . . . . . . . . .
Location of Exit Taxiways . . . . . . . . . . . . . . . .
Design of Taxiway Curves
and Intersections . . . . . . . . . . . . . . . . . . . . .
End-Around Taxiways . . . . . . . . . . . . . . . . . . .
Aprons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Holding Aprons . . . . . . . . . . . . . . . . . . . . . . . .
Terminal Aprons and Ramps . . . . . . . . . . . . .
Terminal Apron Surface Gradients . . . . . . . .
Control Tower Visibility Requirements . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
173
173
174
176
177
177
177
178
178
181
181
181
183
186
191
201
205
207
213
213
213
216
221
222
223
228
228
229
234
234
238
244
249
250
250
252
254
254
255
Contents
7
8
Structural Design of Airport Pavements . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Soil Investigation and Evaluation . . . . . . . . . . . . . . .
The CBR Test . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Plate Bearing Test . . . . . . . . . . . . . . . . . . .
Young’s Modulus (E Value) . . . . . . . . . . . . . .
Effect of Frost on Soil Strength . . . . . . . . . . . . . . . . . .
Subgrade Stabilization . . . . . . . . . . . . . . . . . . . . . . . . .
FAA Pavement Design Methods . . . . . . . . . . . . . . . .
Equivalent Aircraft Method . . . . . . . . . . . . . .
Cumulative Damage Failure Method . . . . . .
Design of Flexible Pavements . . . . . . . . . . . . . . . . . . .
CBR Method . . . . . . . . . . . . . . . . . . . . . . . . . . .
Layered Elastic Design . . . . . . . . . . . . . . . . . . .
Design of Rigid Pavements . . . . . . . . . . . . . . . . . . . . .
Westergaard’s Analysis . . . . . . . . . . . . . . . . . .
Finite Element Theory . . . . . . . . . . . . . . . . . . .
Joints and Joint Spacing . . . . . . . . . . . . . . . . . . . . . . . .
Continuously Reinforced Concrete Pavements . . . .
Design of Overlay Pavements . . . . . . . . . . . . . . . . . .
Pavements for Light Aircraft . . . . . . . . . . . . . . . . . . .
Pavement Evaluation and Pavement
Management Systems . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
257
257
259
263
263
266
266
267
268
269
270
271
272
273
275
275
276
277
279
282
286
Airport Lighting, Marking, and Signage . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Requirements for Visual Aids . . . . . . . . . . . . . . .
The Airport Beacon . . . . . . . . . . . . . . . . . . . . .
Obstruction Lighting . . . . . . . . . . . . . . . . . . . .
The Aircraft Landing Operation . . . . . . . . . . .
Alignment Guidance . . . . . . . . . . . . . . . . . . . .
Height Information . . . . . . . . . . . . . . . . . . . . .
Approach Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Configurations . . . . . . . . . . . . . . . . . . .
Visual Approach Slope Aids . . . . . . . . . . . . . . . . . . . .
Visual Approach Slope Indicator . . . . . . . . . .
Precision Approach Path Indicator . . . . . . . .
Threshold Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway Edge Lights . . . . . . . . . . . . . . . . . . . .
Runway Centerline and Touchdown
Zone Lights . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway End Identifier Lights . . . . . . . . . . . .
291
291
292
293
293
293
294
294
296
296
301
301
302
303
303
304
287
288
304
309
ix
x
Contents
9
10
Taxiway Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Taxiway Edge Lights . . . . . . . . . . . . . . . . . . . .
Runway Guard Lights . . . . . . . . . . . . . . . . . . .
Runway Stop Bar . . . . . . . . . . . . . . . . . . . . . . .
Runway and Taxiway Marking . . . . . . . . . . . . . . . . .
Runways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Runway Designators . . . . . . . . . . . . . . . . . . . .
Runway Threshold Markings . . . . . . . . . . . . .
Centerline Markings . . . . . . . . . . . . . . . . . . . .
Aiming Points . . . . . . . . . . . . . . . . . . . . . . . . . .
Touchdown Zone Markings . . . . . . . . . . . . . .
Side Stripes . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Displaced Threshold Markings . . . . . . . . . . .
Blast Pad Markings . . . . . . . . . . . . . . . . . . . . .
Taxiway Markings . . . . . . . . . . . . . . . . . . . . . .
Centerline and Edge Markings . . . . . . . . . . . .
Taxiway Hold Markings . . . . . . . . . . . . . . . . .
Taxiway Shoulders . . . . . . . . . . . . . . . . . . . . . .
Enhanced Taxiway Markings . . . . . . . . . . . . . . . . . . .
Closed Runway and Taxiway Markings . . . .
Airfield Signage . . . . . . . . . . . . . . . . . . . . . . . .
Runway Distance Remaining Signs . . . . . . . .
Taxiway Guidance Sign System . . . . . . . . . . .
Taxiway Designations . . . . . . . . . . . . . . . . . . .
Types of Taxiway Signs . . . . . . . . . . . . . . . . . .
Signing Conventions . . . . . . . . . . . . . . . . . . . .
Sign Size and Location . . . . . . . . . . . . . . . . . . .
Sign Operation . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
310
311
313
314
315
315
315
320
320
320
321
321
321
322
323
323
325
326
328
328
329
330
331
331
333
337
338
340
341
Airport Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Purpose of Drainage . . . . . . . . . . . . . . . . . . . . .
Design Storm for Surface Runoff . . . . . . . . . .
Determining the Intensity-Duration
Pattern for the Design Storm . . . . . . . . . . .
Determining the Amount of Runoff by
the FAA Procedure . . . . . . . . . . . . . . . . . . . .
Determining the Amount of Runoff by
the Corps of Engineers Procedure . . . . . . .
Layout of Surface Drainage . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
343
343
343
Planning and Design of the Terminal Area . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Passenger Terminal System . . . . . . . . . . . . . . . . .
Components of the System . . . . . . . . . . . . . . .
383
383
383
383
344
347
358
368
380
Contents
Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . .
Terminal Demand Parameters . . . . . . . . . . . .
Facility Classification . . . . . . . . . . . . . . . . . . . .
Overall Space Approximations . . . . . . . . . . . .
Level of Service Criteria . . . . . . . . . . . . . . . . .
The Terminal Planning Process . . . . . . . . . . . . . . . . .
Space Programming . . . . . . . . . . . . . . . . . . . . .
Other Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overall Space Requirements . . . . . . . . . . . . . .
Concept Development . . . . . . . . . . . . . . . . . . .
Horizontal Distribution Concepts . . . . . . . . .
Vertical Distribution Concepts . . . . . . . . . . . .
Schematic Design . . . . . . . . . . . . . . . . . . . . . . .
Analysis Methods . . . . . . . . . . . . . . . . . . . . . . .
Design Development . . . . . . . . . . . . . . . . . . . .
The Apron Gate System . . . . . . . . . . . . . . . . . . . . . . . .
Number of Gates . . . . . . . . . . . . . . . . . . . . . . .
Ramp Charts . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Aircraft Parking Type . . . . . . . . . . . . . . . . . . . .
Apron Layout . . . . . . . . . . . . . . . . . . . . . . . . . .
Apron Circulation . . . . . . . . . . . . . . . . . . . . . . .
Passenger Conveyance to Aircraft . . . . . . . . .
Apron Utility Requirements . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
387
393
394
396
397
399
400
415
416
416
417
423
426
427
441
442
442
448
453
455
456
457
457
458
461
Part 3 Special Topics in Airport Planning and Design
11
Airport Security Planning . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
History of Airport Security . . . . . . . . . . . . . . . . . . . . .
Airport Security Program . . . . . . . . . . . . . . . . . . . . . .
Security at Commercial Service Airports . . . . . . . . .
Passenger Screening . . . . . . . . . . . . . . . . . . . . .
Baggage Screening . . . . . . . . . . . . . . . . . . . . . .
Employee Identification . . . . . . . . . . . . . . . . .
Perimeter Security . . . . . . . . . . . . . . . . . . . . . .
Vulnerability Assessment . . . . . . . . . . . . . . . . . . . . . .
Security at General Aviation Airports . . . . . . . . . . . .
Future Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
467
467
468
470
472
473
475
476
477
477
481
481
482
12
Airport Airside Capacity and Delay . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Capacity and Delay Defined . . . . . . . . . . . . . . . . . . . .
Capacity and Delay in Airfield Planning . . .
483
483
484
485
xi
xii
Contents
Approaches to the Analysis of Capacity and Delay . . . .
Factors That Affect Airfield Capacity . . . . . .
Formulation of Runway Capacity through
Mathematical Theory . . . . . . . . . . . . . . . . . . . . . . .
Mathematical Formulation of Delay . . . . . . .
Formulation of Runway Capacity through
the Time-Space Concept . . . . . . . . . . . . . . . . . . . . .
Formulation of Ultimate Capacity . . . . . . . . . . . . . . .
Mathematical Formulation of
Ultimate Capacity . . . . . . . . . . . . . . . . . . . .
Application of Techniques for Ultimate
Hourly Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parameters Required for Runway
Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Computation of Delay on Runway Systems . . . . . .
Graphical Methods for Approximating
Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Application of Techniques for Annual
Service Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Simulation Models . . . . . . . . . . . . . . . . . . . . . .
Gate Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analytical Models for Gate Capacity . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Finance Strategies for Airport Planning . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Federal Funding Programs in the United States . . . . .
The Airport Development Aid
Program
............................
The Passenger Facility Charge
Program
............................
State and Local Participation in Financing
Airport Improvements . . . . . . . . . . . . . . . . . . . . . .
Bond Financing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Obligation Bonds
...............
General Airport Revenue Bonds . . . . . . . . . .
Special Facility Bonds . . . . . . . . . . . . . . . . . . .
PFC Bonds . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CFC Bonds . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Privatization of Airports . . . . . . . . . . . . . . . . . . . . . . .
Financial Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rate Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evaluation of the Financial Plan . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
486
489
490
490
492
497
497
514
514
520
525
532
537
538
539
541
543
543
543
544
547
556
557
558
558
559
559
560
560
560
562
564
571
571
Contents
14
15
Environmental Planning . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Policy Considerations . . . . . . . . . . . . . . . . . . . . . . . . .
Pollution Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . .
Aircraft and Airport Noise . . . . . . . . . . . . . . .
Sound Pressure and Sound Pressure Level . . .
Aircraft Noise Effects and Land-Use
Compatibility
.......................
Determining the Extent of the Problem . . . .
Finding Solutions . . . . . . . . . . . . . . . . . . . . . . .
Noise Regulations . . . . . . . . . . . . . . . . . . . . . . .
Construction Impacts . . . . . . . . . . . . . . . . . . . .
Social Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Land Development . . . . . . . . . . . . . . . . . . . . . .
Displacement and Relocation . . . . . . . . . . . . .
Parks, Recreational Areas, Historical Places,
Archeological Resources,
and Natural and Scenic Beauty . . . . . . . . .
Consistency with Local Planning . . . . . . . . . .
Ecological Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wildlife, Waterfowl, Flora, Fauna,
Endangered Species . . . . . . . . . . . . . . . . . . .
Wetlands and Coastal Zones . . . . . . . . . . . . . .
Flood Hazards . . . . . . . . . . . . . . . . . . . . . . . . . .
Engineering and Economic Factors . . . . . . . . . . . . . .
Costs of Construction and Operation . . . . . .
Economic Benefits and Fiscal Requirements . . .
Energy and Natural Resources . . . . . . . . . . . .
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
573
573
574
576
576
577
579
580
Heliports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heliports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Nature of Helicopter Transportation . . .
Characteristics of Helicopters . . . . . . . . . . . . .
Factors Related to Heliport Site Selection . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
629
629
629
629
630
631
648
Index
651
.......................................
592
598
604
609
615
616
616
617
617
618
619
619
619
620
620
620
624
624
625
625
xiii
This page intentionally left blank
Preface
I
n the preface to the fourth edition of this text, the late Dr. Francis
McKelvey remarked that the technological and legislative developments related to the air transportation industry in the 1980s
and early 1990s were of such significance that an updating of the book
was needed. The fourth edition, published in 1994, enhanced previous
editions, the first of which was published in 1962.
In the 16 years since this last update, it may be said that the
changes to the practice of airport planning and design have been
more significant than in any other era in the history of aviation.
Implementation of twenty-first-century technologies has resulted in
the first major overhaul to aircraft and air navigation systems in
generations, computer-based analytical and design models have
replaced antiquated monographs and estimation tables, and highly
significant geopolitical events have all but rewritten the rules of
planning, designing, and operating civil-use airports.
These significant enhancements to the aviation system have
resulted in unique challenges in creating an updated fifth edition of
this important and highly accepted text. While every attempt was
made to keep to the traditional structure of the book and to preserve
the theoretical strengths for which it is most well known, much of the
material in the previous edition required more replacement than
simply being made current. Within this latest edition the reader will
find, for example, new and entirely different strategies to estimate
required runway lengths and their associated required pavement
thicknesses. This text attempts to maintain the flavor of previous
editions while understanding, for example, that airport navigational
aids of the previous century are becoming all but obsolete, in favor
of a digital, satellite-based communication and navigational system,
and that airport financing strategies are in a revolutionary state, given
anticipated changes to federal aviation funding mechanisms.
Updating this edition has, in fact, been a continuous “race against
time,” as important changes to the aviation system were constantly
occurring during the process.
xv
xvi
Preface
In light of these challenges, this fifth edition is hoped to again be
the standard text for those interested in the fundamentals of airport
planning and design. The information located within these chapters
is applicable both for academic coursework and as a reference on the
desks of airport planning and design professionals. As the industry
continues to move forward, it is of course recommended that
the latest design standards published by the Federal Aviation
Administration, the International Civil Aviation Organization, and
local, state, and other federal agencies be consulted.
Seth B. Young, Ph.D.
Acknowledgments
T
he fifth edition of this historic text could never have been
created without the career efforts of its original author, the late
Dr. Robert Horonjeff, and his coauthor on later editions, the
late Dr. Francis McKelvey. Their authorship will always be first
credited. Updating this book without their personal guidance was
immensely challenging. It is only hoped that they would be satisfied
with knowing their original philosophies still form the basis for
this text. Contributing to this update have been the fine efforts of
Dr. William Sproule, who studied under Dr. McKelvey and helped
bring his goal of maintaining the currency of this text to fruition.
Many thanks go out to the institutions at which the original
authors were, and those who helped update this latest edition have
been, lucky enough to be employed: the University of California at
Berkeley, Michigan State University, Embry-Riddle Aeronautical
University, Michigan Technological University, Jacobs Consultancy,
and The Ohio State University. It is hoped that the students, faculty,
and professionals of these and all such institutions continue to find
this text a valuable resource.
This book is dedicated to the memories of Dr. Horonjeff and
Dr. McKelvey, who have helped to immortalize the formal practice of
planning and designing the world’s airports. Their life’s efforts have
resulted in bettering the lives of countless students, professionals,
and users of civil aviation.
Seth B. Young, Ph.D.
xvii
This page intentionally left blank
PART
1
Airport
Planning
CHAPTER 1
The Nature of Civil Aviation
and Airports
CHAPTER 3
Air Traffic Management
CHAPTER 2
CHAPTER 4
Airport Planning Studies
Aircraft Characteristics
Related to Airport Design
CHAPTER 5
Forecasting for Airport Planning
This page intentionally left blank
CHAPTER
1
The Nature of
Civil Aviation
and Airports
Introduction
Since its beginning in the early twentieth century, civil aviation has
become one of the most fascinating, important, and complex industries in the world. The civil aviation system, particularly its airports,
has come to be the backbone of world transport and a necessity to
twenty-first-century trade and commerce.
In 2008, the commercial service segment of civil aviation, consisting of more than 900 airlines and 22,000 aircraft, carried more
than 2 billion passengers and 85 million tons of cargo on more than
74 million flights to more than 1700 airports in more than 180 countries worldwide. Millions more private, corporate, and charter
“general aviation” operations were conducted at thousands of commercial and general aviation airports throughout the world. In many
parts of the world, commercial service and general aviation serve
as the primary, if not the only method of transportation between
communities.
The magnitude of the impact of the commercial air transportation industry on the world economy is tremendous, contributing
more than $2.6 trillion in economic activity, equivalent to 8 percent
of the world gross domestic product, and supporting 29 million
jobs. In the United States alone civil aviation is responsible for
$900 billon in economic activity and 11 million jobs. General aviation serves an equally important role in the world’s economy, providing charter, cargo, corporate, medical, and private transport, as
well as such services as aerial photography, firefighting, surveillance, and recreation. In the United States alone, there are more
than 225,000 registered general aviation aircraft and more than
600,000 registered pilots.
3
4
Airport Planning
The presence of civil aviation has affected our economic way of
life, it has made changes in our social and cultural viewpoints, and
has had a hand in shaping the course of political history.
The sociological changes brought about by air transportation are
perhaps as important as those it has brought about in the economy.
People have been brought closer together and so have reached a better understanding of interregional problems. Industry has found new
ways to do business. The opportunity for more frequent exchanges of
information has been facilitated, and air transport is enabling more
people to enjoy the cultures and traditions of distant lands.
In recent years, profound changes in technology and policy have
had significant impacts on civil aviation and its supporting airport
infrastructure. The industry continues to grow in numbers of aircraft,
passengers and cargo carried, and markets served, from nonstop
service on superjumbo aircraft between cities half-way across the
planet, to privately operated “very light jets” between any of thousands of small airports domestically. Growth encouraged from technological advancements countered with increased constraints on the
civil aviation system due to increased capacity limitations, security
regulations, and financial constraints have resulted in ever increasing
challenges to airport planning and design.
Civil aviation is typically considered in three sectors, commercial
service aviation (more commonly known as air carriers or airlines),
air cargo, and general aviation. Although the lines between these traditional sectors are becoming increasingly blurred, the regulations
and characteristics regarding their individual operations are often
mutually exclusive, and as such, those involved in airport planning
and design should have an understanding of each sector.
Commercial Service Aviation
Commercial service aviation, supported by the world’s airlines, is by
far the most well known, most utilized, and most highly regulated
segment of civil aviation. It is the segment of the industry responsible
for providing public air transportation between the world’s cities.
In the United States, domestic commercial air service accommodated nearly 650 million enplaning passengers in 2008, flying
approximately 570 billion passenger-miles, reflecting a slight decline
following the most recent surge in the growth of air transportation
since the mid-twentieth century, and forecasted to carry more than
1 billion passengers by 2020, as illustrated in Fig. 1-1.
Intercity travel, of course, is not solely available through commercial service aviation. Intercity travel may be accommodated using
either private modes of transportation, most commonly via private
automobile travel, or through other modes of public transportation,
such as bus, rail, or ship. Private automobile travel, accounts for
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Passengers (thousands)
Passenger-Miles (millions)
1,200,000
1,000,000
Historical
Forecast
Revenue Passengers (thousands)
Revenue Passenger-Miles (millions)
800,000
600,000
400,000
200,000
0
1940 1950 1960 1970 1980 1990 2000 2010 2020 2030
Year
FIGURE 1-1 Total scheduled U.S. domestic passenger traffic: 1940 to 2020
(U.S. Bureau of Transportation Statistics).
nearly 90 percent of the total intercity (defined as trips greater than
50 mi in distance) travel in the United States, and public transportation or common-carrier travel (bus, rail, and air) accounts for the
remaining portion.
Since the later half of the twentieth century, there has been a
steady increase in overall travel, by private automobile and public
transportation. Air transportation has had the greatest increase in
overall passengers served. In the United States, this period has also
witnessed a dramatic reduction in rail travel except for the rail markets in the Northeast United States. These relationships are shown in
Table 1-1.
As illustrated in Table 1-2, air transportation in the United States
accounts for the vast majority of domestic travel for trips exceeding
750 mi, and approximately one third of trips 500 to 750 mi in length. In
all, air transportation accounts for approximately 70 percent of the
United States’ public intercity transportation. With the exception of
travel to Canada and Mexico, air transportation serves nearly 100 percent of travel between the United States and international destinations.
In many parts of the world the use of private automobile is much
less significant, and the use of rail transportation is much more prevalent. However, growth in commercial aviation in markets such as
Europe and India are forecast to take greater numbers of passengers
off the rails and onto airlines.
Much of the historical growth in air carrier transportation has been
largely credited to the 1978 Federal Airline Deregulation Act, which
allowed air carriers to freely enter and compete in domestic markets in
5
6
Airport Planning
Annual
Growth,
%
Civil
Aviation
Annual
Growth,
%
Rail
Annual
Growth,
%
Year
Highway
1960
1,272,078
1965
1,555,237
22
57,626
73
17,388
–18
1970
2,042,002
31
117,542
104
10,771
–38
1975
2,404,954
18
147,400
25
8,444
–22
1980
2,653,510
10
219,068
49
11,019
30
1985
3,012,953
14
290,136
32
11,359
3
1990
3,561,209
18
358,873
24
13,139
16
1995
3,868,070
9
414,688
16
13,789
5
2000
4,390,076
13
531,329
28
14,900
8
2005
4,884,557
11
603,689
14
15,381
3
33,399
21,261
Source: U.S. Bureau of Transportation Statistics.
TABLE 1-1
U.S. Passenger Travel by Mode
the United States, and “open skies” agreements throughout the 1990s
between nations to allow for more service between international destinations. The most recent growth in air transportation is attributable to
changing airline business models, such as the emergence of the “lowcost carrier” (LCC), as well as increasing numbers of international open
skies agreements that have proliferated since 2000.
One-Way Distance
50–499
Miles
500–749
Miles
750–999
Miles
1000–1499
Miles
1500 +
Miles
95.4
61.8
42.3
31.5
14.8
Air
1.6
33.7
55.2
65.6
82.1
Bus
2.1
3.3
1.5
1.5
1.4
Train
0.8
1.0
0.9
0.7
0.8
Other
0.2
0.1
0.1
0.7
1.0
Total
89.8
3.1
2.0
2.3
2.8
Mode
Personal
vehicle
TABLE 1-2
Percent of Trips by Mode for One-Way Travel Distance
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Passenger Air Carriers
Commercial air carriers are defined in the United States as those that
operate under Title 14 Part 121 of the U.S. Code of Federal Regulations to provide scheduled air transportation to the public. In the
United States, these airlines are categorized by their annual revenues.
Major airlines are those that generate at least $1 billion in annual revenues. National carriers generate between $100 million and $1 billion
in annual revenues, and regional carriers generate between $25 million
and $100 million in annual revenues.
International air carriers receive operating certificates as prescribed by standards set by the International Civil Aviation Organization (ICAO) and defined by the country in which the airline is
based. Historically, international air carriers were owned and operated by their nations, hence the term “flag” carriers. In recent years,
most of the traditional international carriers have been transferred to
private ownership. In addition, there has been an emergence of new
international air carriers, most following the LCC model of serving
point-to-point markets for fares that are on the whole far lower than
their historical airline counterparts. The emergence of the LCC models
in Europe and more recently in the Far East and India are resulting
in a tremendous growth in aviation activity in these regions.
Air carriers using aircraft with less than 75 seats providing scheduled or unscheduled air charter services operating under Title 14
Part 121 of the U.S. Code of Federal Regulations are known as regional
air carriers. Those carriers operating aircraft with less than 30 seats
and those that operate under Title 14 Part 135 of the U.S. Code of
Federal Regulations are known as commuter air carriers. If service
frequency between city pairs is provided less than 5 times weekly,
these carriers are known as air taxi operators.
In 2008, there were over 700 air taxis, commuter and small regional
air carriers operating more than 2750 aircraft, over 50 percent of
which were regional jet aircraft. Six hundred and forty two airports in
the United States received service by small regional and commuter
airlines. Regional and commuter air service is the sole provider of
public air transportation to 492 airports in the United States (source:
RAA). Throughout the 1980s and 1990s, commuter airline growth
was encouraged by their increasing roles as code-share partners with
major air carriers. In 2006, over 95 percent of all passengers traveling
on commuter and regional air carriers purchased their tickets through
these code-share partnerships. Table 1-3 illustrates the growth of the
commuter and regional carriers since 1970.
International Air Transportation
Although international air transport was inaugurated in the mid1930s, rapid growth did not begin until 1950. Since that time the
average annual growth rate in the number of worldwide passengers
7
8
Airport Planning
Average
Trip
Length
(miles)
Average
Seats per
Aircraft
Year
Enplaned
Passengers
(thousands)
Passenger
Miles
(millions)
1970
4,270
399
98
741
11
1975
7,243
689
110
948
13
1980
14,810
1,920
129
1,339
14
1985
26,000
4,410
173
1,745
19
1990
42,099
7,610
183
1,917
22
1995
55,800
11,461
213
2,109
30
2000
82,800
23,638
285
2,275
39
2003
112,120
43,100
384
2,189
45
2007
161,390
73,690
457
2,579
51
Number
of Aircraft
TABLE 1-3 Commuter and Regional Airline Statistics 1970 to 2007
was nearly 14 percent in the 1960s, slightly less than 7 percent in the
1970s, and slightly less than 5 percent in the 1980s. As illustrated in
Fig. 1-2, worldwide growth in air transportation has increased by
more than 60 percent between 1990 and 2005.
Air Cargo
Revenue Passengers (thousands)
Revenue Passenger-Miles (millions)
Originating as the transport of mail by air in the early part of the
twentieth century, air cargo has come to be defined as a $40 billion
2,500,000
2,000,000
Revenue Passengers (thousands)
Revenue Passenger-Miles (millions)
1,500,000
1,000,000
500,000
0
1950
1960
1970
1980
Year
1990
2000
FIGURE 1-2 Worldwide growth in civil air transport passenger traffic.
2010
Revenue Ton-Miles (millions)
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
100,000
90,000
80,000
70,000
60,000
50,000
40,000
30,000
20,000
10,000
0
Mail
Freight
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Year
FIGURE 1-3
Worldwide air cargo.
industry focused on the air transport of mail, bulk freight, high-value
goods, and all other revenue generating payload other than passengers and their luggage. As illustrated in Fig. 1-3, the transport of air
cargo has increased tremendously since the mid-twentieth century,
with its greatest rate of growth occurring since the late 1980s.
The top 50 carriers of air cargo in the global air cargo industry
carried nearly one-hundred billion freight-ton-miles of cargo in 2008.
Approximately 15 percent of the air cargo transported globally is performed by industry leaders and exclusive cargo carriers FedEx and
UPS. The majority of air cargo is transported by air carriers, using
aircraft designed exclusively for air cargo carriage, as well as on commercial passenger aircraft. Cargo carried on commercial passenger
aircraft is often referred to as “belly cargo” as the cargo is stowed in
the belly of the passenger aircraft. Cargo carried on aircraft designed
exclusively for the carriage of cargo is often referred to as “palette” or
“containerized” cargo, describing the containers within which cargo
is stowed and the palettes used to load and unload cargo. Cargo
operations using each type aircraft pose unique challenges for airport
planning and design.
The geographic distribution of world air transport is also of
interest. For statistical purposes ICAO has divided the world into six
regions: Asia and Pacific, Europe, North America, Latin American,
Caribbean, and the Middle East.
While slightly more than 60 percent of all traffic is generated in
North America and Europe, the relative growth rates of traffic in
the Asian and Pacific region, as well as in the Middle East, is
expected to dominate worldwide air transportation growth, reflecting
the growth of importance of this area in the political, social, and
economic sectors.
9
10
Airport Planning
Asia and
Pacific
Year
Europe
North
America
Latin
America and
Caribbean
Africa
Middle
East
1972
8.4
35.9
47.6
4.4
2
1.7
1976
12.4
36.5
41
4.8
2.5
2.8
1980
15.5
35
38.6
5.5
2.6
2.8
1984
17.6
33
38
4.9
2.8
3.8
1988
19.8
31
39.3
4.6
2.2
3
1990
19.8
31.9
38.5
4.7
2.2
2.9
1992
21.2
27.3
41.8
4.7
2.2
2.8
2002
26.7
26.2
36.8
4.5
2.2
3.6
2005
33.2
25.4
30.3
4.3
2.1
4.7
TABLE 1-4
Percentage of Worldwide Distribution of Air Cargo Traffic
The air cargo market is forecast to triple between 2008 and 2030,
led by the growth of air freight demand to China, as illustrated by
the forecast percentage distribution of worldwide air cargo activity
in Table 1-4. It is forecast that increasing percentages of air cargo
would be shipped on dedicated cargo aircraft, requiring the need
for expanded exclusive air cargo facilities at airports throughout
the world.
General Aviation
General aviation is the term used to designate all flying done other
than by the commercial air service carriers. General aviation operations range from local recreational flying to global business transport, performed on aircraft not operating under the federal aviation
regulations for commercial air carriers.
While, by definition, general aviation operations carry no
“commercial” passengers, it is estimated that more than 166 million
people traveled by general aviation on nearly 20 million flights in
2008. During 2007, general aviation accounted for nearly 75 percent
of all aircraft operations in the United States (source: FAA TAF). General aviation supports more than 1.3 million jobs and contributes
more than $103 billion annually to the United States economy.
As of 2008, there were approximately 225,000 general aviation
aircraft registered in the United States and an estimated 340,000 aircraft worldwide (source: GAMA). These aircraft range in type and
size from small single-engine propeller aircraft to large jet aircraft, to
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
45,000
Total Hours (thousands)
40,000
Total Hours (thousands)
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
1940
FIGURE 1-4
1950
1960
1970 1980
Year
1990
2000
2010
Total flight hours in general aviation aircraft in the United States.
“ultralight” aircraft, to helicopters. General aviation aircraft are
served by nearly 20,000 landing facilities in the United States alone.
General aviation activity has experienced a decline in activity
between 1980 and 2008, as illustrated in Fig. 1-4. Despite this recent
historical decline, general aviation activity is forecast to increase with
the proliferation of new aircraft technology which is expected to
reduce the cost of general aviation operations. This forecast growth in
general aviation, combined with new technologies, will pose interesting challenges for airport planning and design.
Civil Aviation Airports
Airports serving civil aviation range from private nonpaved strips
that serve less than one privately operated aircraft per day to major
international airports covering tens of thousands of acres, serving
hundreds of thousands of flights and hundreds of millions of passengers annually. In the United States there are approximately 20,000
recognized civil airports, most of which are privately owned and
closed to general public use. Of the approximately 5200 airports
open to the public, approximately 700 are certified to accommodate
commercial air service, with the remaining serving general aviation
exclusively.
Airports currently serving at least 2500 enplaned passengers
using commercial air service are known as commercial service airports.
Primary airports are designated as those commercial airports serving
at least 10,000 annual enplaned passengers. Airports serving less than
2500 annual enplaned passengers are considered general aviation
airports. General aviation airports designed to accommodate smaller
11
12
Airport Planning
3,411
NPIAS Airports
(Of the 5,190 existing public use
airports, 65% are NPIAS)
3,356 Existing
3,254 Public Owned
102 Private Owned
383
Primary
FIGURE 1-5
139
Commercial
Service
270
Reliever
55 Proposed
2,564
General
Aviation
3
Primary
6
Commercial
Service
2
Reliever
44
General
Aviation
NPIAS categories.
single and twin-engine aircraft are considered basic utility airports.
Those general aviation airports that accommodate larger aircraft are
considered general utility airports.
The United States’ Federal Aviation Administration (FAA), the
governmental body with administrative oversight to the nation’s
civil aviation system, categorizes airports through its National Plan
of Integrated Airport Systems (NPIAS). As illustrated in Fig. 1-5 the
NPIAS recognizes approximately 3400 airports considered by the
FAA to be essential to civil aviation and classifies these airports by
the levels of commercial service activity within their respective standard metropolitan statistical areas (SMSAs).
Primary airports are further classified into what are known as
“hub classifications” (not to be confused with the airline “hub and
spoke” route models). The hub classifications used by the FAA are
large hub primary, medium hub primary, small hub primary, and
nonhub primary airports. Large hubs are those airports that account
for at least 1 percent of the total annual passenger enplanements in
the United States. Medium hubs account for at least 0.25 but less
than 1 percent of the total passenger enplanements. Small hubs
account for at least 0.05 percent but less than 0.25 percent, and nonhubs account for less than 0.05 percent but at least 10,000 annual
enplaned passengers. The number of airports, by hub classification,
is illustrated in Table 1-5.
Reliever airports are airports not currently serving regular commercial service but have been designated by the FAA as “general
aviation-type airports that provide relief” when necessary to commercial service airports, typically by accommodating high volumes
of general aviation activity within a metropolitan area and accommodating commercial service operations when the nearby commercial service airport is closed or otherwise cannot accommodate
normal operations. Airports are typically given “reliever” status if they
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Airport Type
Percentage
of 2006 Total
Enplanements
30
Large hub primary
68.7
0.9
37
Medium hub primary
20.0
2.6
72
Small hub primary
8.1
4.3
244
Nonhub primary
3.0
10.9
139
Nonprimary
commercial service
0.1
2.4
270
Relievers
0.0
28.2
2,564
General aviation
0.0
40.8
3,356
Existing NPIAS
airports
99.9
89.8
0.1
10.2
Number of
Airports
16,459
Low-activity landing
areas (Non-NPIAS)
Percentage of All
Based Aircraft
TABLE 1-5 Number of NPIAS Airports by Hub Classification
are located within an SMSA of population of at least 5,000,000 or
where passenger enplanements exceed 250,000 annually. In addition,
the airport must have at least 100 aircraft based at the field or handle
at least 25,000 itinerant operations annually. Reliever airports,
although not serving regular commercial service operations, are
among the busiest airports in the United States.
While most of the airports in the United States are privately
owned and operated, the majority of public use airports are in fact
publicly owned. Public use airports, and commercial service airports
in particular, are typically owned and operated by local municipalities, counties, states, or some public “authority” typically overseen
by representatives from a combination of local and regional jurisdictions. There are a few public use airports that are operated by private
airport management companies but rarely do private firms actually
own the property on which the airport is located. As such, in the
United States, most planning and design programs at civil public use
airports must go through extensive governmental processes for ultimate approval and often funding support.
While the United States has by far the greatest number of commercial service and general aviation airports in the world, many of
the world’s largest and most important airports are located all over
the globe. Table 1-6 lists the world’s busiest airports.
13
Total Passenger Traffic 2008
Rank
Total Operations (Movements) 2008
City
Airport
Passengers
Rank
City
Airport
Movements
1
Atlanta, GA
ATL
90,039,280
1
Atlanta, GA
ATL
978,824
2
Chicago, IL
ORD
69,353,654
2
Chicago, IL
ORD
3
London, GB
LHR
67,056,228
3
Dallas/Ft
Worth, TX
4
Tokyo, JP
HND
66,735,587
5
Paris, FR
CDG
60,851,998
4
5
6
Los Angeles,
CA
LAX
59,542,151
6
7
Dallas/Ft
Worth, TX
DFW
57,069,331
8
Beijing, CN
PEK
9
Frankfurt, DE
10
Total Cargo (Metric Tons) 2008
Rank
City
Airport
Metic Tons
1
Memphis,
TN
MEM
3,695,561
881,566
2
Hong Kong,
CN
HKG
3,656,724
DFW
656,310
3
Shanghai,
CN
PVG
2,698,795
Denver, CO
DEN
615,573
4
Seoul, KR
ICN
2,423,717
Los Angeles,
CA
LAX
615,525
5
Anchorage,
AK
ANC
2,361,088
Las Vegas,
NV
LAS
579,949
6
Paris, FR
CDG
2,280,049
7
Houston, TX
IAH
576,062
7
Frankfurt,
DE
FRA
2,111,116
55,662,256
8
Paris, FR
CDG
559,812
8
Tokyo, JP
NRT
2,099,349
FRA
53,467,450
9
Charlotte, NC
CLT
536,253
9
Louisville,
KY
SDF
1,973,965
Denver, CO
DEN
51,435,575
10
Phoenix, AZ
PHX
502,499
10
Singapore,
SG
SIN
1,883,894
11
Madrid, ES
MAD
50,823,105
11
Philadelphia,
PA
PHL
492,010
11
Dubai, AE
DXB
1,824,992
12
Hong Kong,
CN
HKG
47,898,000
12
Frankfurt, DE
FRA
485,783
12
Miami, FL
MIA
1,806,769
13
New York, NY
JFK
47,790,485
13
London, GB
LHR
478,569
13
Los Angeles,
CA
LAX
1,630,385
14
Amsterdam,
NL
AMS
47,429,741
14
Madrid, ES
MAD
469,740
14
Amsterdam,
NL
AMS
1,602,584
15
Las Vegas,
NV
LAS
44,074,707
15
Detroit, MI
DTW
462,284
15
Taipei, TW
TPE
1,493,120
16
Houston, TX
IAH
41,698,832
16
Minneapolis/
St Paul, MN
MSP
446,840
16
London, GB
LHR
1,486,260
17
Phoenix, AZ
PHX
39,890,896
17
Amsterdam,
NL
AMS
446,626
17
New York,
NY
JFK
1,446,491
18
Bangkok, TH
BKK
38,604,009
18
New York, NY
JFK
435,750
18
Chicago, IL
ORD
1,324,820
19
Singapore,
SG
SIN
37,694,824
19
Newark, NJ
EWR
433,463
19
Beijing, CN
PEK
1,303,258
20
Dubai, AE
DXB
37,441,440
20
Munich, DE
MUC
432,296
20
Bangkok, TH
BKK
1,173,131
21
San
Francisco, CA
SFO
37,405,467
21
Beijing, CN
PEK
431,675
21
Indianapolis,
IN
IND
1,025,895
22
Orlando, FL
MCO
35,622,252
22
Toronto, ON,
CA
YYZ
429,829
22
Newark, NJ
EWR
889,121
23
Newark, NJ
EWR
35,299,719
23
San
Francisco,
CA
SFO
387,710
23
Tokyo, JP
HND
849,378
TABLE 1-6 The World’s Busiest Airports
Total Passenger Traffic 2008
Total Operations (Movements) 2008
Total Cargo (Metric Tons) 2008
Rank
City
Airport
Passengers
Rank
City
Airport
Movements
Rank
City
Airport
Metic Tons
24
Detroit, MI
DTW
35,144,841
24
Salt Lake
City, UT
SLC
387,695
24
Osaka, JP
KIX
845,496
25
Rome, IT
FCO
35,132,879
25
Los Angeles,
CA
VNY
386,706
25
Luxembourg,
LU
LUX
788,223
26
Charlotte, NC
CLT
34,732,584
26
New York, NY
LGA
377,940
26
Guangzhou,
CN
CAN
685,866
27
Munich, DE
MUC
34,530,593
27
Phoenix, AZ
DVT
376,210
27
Kuala
lumpur, MY
KUL
661,212
28
London, GB
LGW
34,214,474
28
Miami, FL
MIA
372,635
28
Dallas/Pt
Worth, TX
DFW
660,465
29
Miami, FL
MIA
34,063,531
29
Boston, MA
BOS
371,604
29
Atlanta, GA
ATL
655,277
30
Minneapolis/
St Paul, MN
MSP
34,032,710
30
Mexico City,
MX
MEX
366,561
30
Brussels, BE
BRU
616,423
Source: Airports Council International.
TABLE 1-6 The World’s Busiest Airports (Continued)
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Contrary to the ownership structures in the United States, airports
worldwide have traditionally been owned and operated by their
respective federal governments through their ministries of transport,
however many are increasingly becoming privatized to operate as forprofit business entities.
Historical Review of the Legislative Role in Aviation
Both in the United States and internationally, legislative actions taken
by federal and state governments have had a profound impact on the
growth of civil aviation and the planning and design of its airports.
As early as 1911, the Post Office Department showed an interest
in civil aviation, particularly the transportation of mail by air, and
from then on the department did much to encourage civil aviation.
Attempts to obtain federal appropriations for air-mail began in 1912
but met with little success until 1916, when an appropriation for
experimental purposes was made. In 1918, the first air-mail route in
the United States was established between Washington, D.C. and
New York City. At the start of this service the flying operations were
conducted by the War Department but later that year the Post Office
Department took over the entire operation with its own equipment
and pilots. Service was inaugurated between New York City and
Chicago in 1919 and was extended to San Francisco in 1920.
The Post Office Department, having demonstrated the practicality of moving mail by air, desired to turn over the operation to private
enterprise. By 1925, the development work of the government had
reached a stage where private operation seemed feasible. Accordingly, legislation permitting the Post Office Department to contract
with private operators for the carriage of mail by air was provided by
the Air Mail Act of 1925 (Kelly Act). However, it was not until 1926
that a number of contract routes were opened. Some of the early contractors were the Ford Motor Company, Boeing Air Transport (predecessor of United Airlines), and National Air Transport.
Air Commerce Act of 1926
The first year of the carriage of mail also saw the passage of the first
federal law dealing with air commerce, the Air Commerce Act of 1926
(Public Law 64-254). Although this law provided regulatory measures, it did more to aid and encourage civil aviation than to regulate.
The principal provisions of this act were as follows:
1. All aircraft owned by United States citizens operating in
common-carrier service or in connection with any business
must be registered.
2. All aircraft must be certificated and operated by certified
airmen.
17
18
Airport Planning
3. Authority was given to the Secretary of Commerce to establish air traffic rules.
4. The Secretary of Commerce was authorized to establish,
operate, and maintain lighted civil airways.
In drafting the legislation, Congress relied considerably upon the
precedents in maritime law. An analogy was utilized between the role
of the government in meeting water navigation needs and the role of
the government in air navigation. In water navigation these services
included the signing, lighting, and marking of channels, safety inspection of ships and operating personnel, assistance in the development
and improvement of ports and waterways, and laws concerning the
operations of the industry. The provision of docks and terminal facilities were the responsibility of local government or the private sector
of the economy. Therefore, the legislation was adopted in such a
framework which held that airports were analogous to the docks of
waterborne transportation [30].
Under the Air Commerce Act, control of air transportation was
divided among several government agencies. The air-mail contracts
were let by the Post Office Department, air-mail rates were subject to
regulation by the Interstate Commerce Commission, and matters
having to do with registration, certification, and airways were vested
in the Bureau of Air Commerce in the Department of Commerce. The
result of this divided jurisdiction was a lack of coordination in the
efforts of government to develop the air transportation industry. In
addition, the Act specifically prohibited any direct federal funding
for airport development.
Civil Aeronautics Act of 1938
The Air Commerce Act of 1926 had been passed before the carriage
of mail and passengers had developed into a substantial business
enterprise. The failure of this legislation to provide adequate economic control led to wasteful and destructive competitive practices.
The carriers had little security in their routes and therefore could not
attract private investors and develop traffic volumes sufficient to
achieve economic stability. These particular weaknesses in the existing legislation led to the enactment of the Civil Aeronautics Act of
1938 (Public Law 76-706). This act defined in a precise manner the
role of the federal government in respect to the economic phases of
air transport. It created one independent agency to foster and regulate air transport in lieu of the three agencies operating under the Air
Commerce Act. This new agency was called the Civil Aeronautics
Authority (not to be confused with the Civil Aeronautics Administration). It consisted of a five-member authority, a three-member air
safety board, and an administrator. The five-member authority was
principally concerned with the economic regulation of air carriers;
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
the safety board was an independent body for the investigation of
accidents; and the concerns of the administrator dealt primarily with
construction, operation, and maintenance of the airways.
During the first year and a half of its existence a number of
organizational difficulties arose within the Civil Aeronautics Authority.
As a result, President Franklin D. Roosevelt, acting within the authority granted to him in the Reorganization Act of 1939 (55 Stat. 561),
reorganized the Civil Aeronautics Authority and created two separate agencies, the Civil Aeronautics Board and the Civil Aeronautics
Administration. The five-member authority remained as an independent agency and became known as the Civil Aeronautics Board;
the Air Safety Board was abolished and its functions given to the
Civil Aeronautics Board; and the administrator became the head of
an agency within the Department of Commerce known as the Civil
Aeronautics Administration (CAA). The duties of the original fivemember authority were unchanged, except that certain responsibilities, such as accident investigation, were added because of the
abolition of the Air Safety Board. The administrator, in addition to
retaining the functions of supervising construction, maintenance,
and operation of the airways, was required to undertake the administration and enforcement of safety regulations and the administration of the laws with regard to aircraft operation. Subsequently,
the administrator became directly responsible to the Secretary of
Commerce (1950).
The Civil Aeronautics Act, like its predecessor the Air Commerce
Act, authorized the federal government to establish, operate, and
maintain the airways, but again, authorization for actively aiding airport development was lacking. The act, however, authorized the
expenditure of federal funds for the construction of landing areas
provided the administrator certified “that such landing area was reasonably necessary for use in air commerce or in the interests of
national defense.” The act also directed the administrator to make a
survey of airport needs in the United States and report to Congress
about the desirability of federal participation and the extent to which
the federal government should participate.
In accordance with the requirements of the Act, the Civil
Aeronautics Authority conducted a detailed survey of the airport
needs of the nation. An advisory committee was appointed, composed of representatives of interested federal agencies (both military
and civil), state aviation officials, airport managers, airline representatives, and others. A report was submitted to Congress on March 23,
1939 (House Document 245, 76th Congress, 1st Session). Some of the
more important recommendations in this report were as follows:
1. Development and maintenance of an adequate system of airports and seaplane bases should be recognized in principle as
a matter of national concern.
19
20
Airport Planning
2. Such a system should be regarded, under certain conditions,
as a proper object of federal expenditure.
3. In passing upon applications for federal expenditure on airport development or improvement, the highest preference
should be given to airports which are important to the maintenance of safe and efficient operation of air transportation
along the major trade routes of the nation; and to those rendering special service to the national defense.
4. At such times as the national policy includes the making of
grants to local units of government for public-works purposes,
or any work-relief activity, a proportion of the funds involved
should be allocated to airport purposes. Such purposes should
be given preference as rendering an important service to the
localities concerned and at the same time being of particular
importance to the nation’s commerce and defense.
5. Whenever emergency public-works programs may be terminated, or when such programs may be curtailed to a degree not
enabling adequate airport development to continue, or when
the Congress for other reasons may determine federal assistance for airports should be continued through annual appropriations for that purpose, based upon annual reports which
should include a review of the general status of the nation’s
airport system and of the work recently done or currently in
course of being done, and recommendations for future work in
the interest of developing and maintaining a system adequate
to national needs, expenditures at these periods should be limited to projects of exceptional national interest.
6. In connection with such public-works or work-relief programs as normally involve joint contributions by the federal
government and by local government, there should be a
provision of supplementary funds to enable the federal
government to increase its share of the total expense, in
any proportion justified by the importance of the project.
7. All applications for federal airport grants from such a supplementary appropriation should be presented through agencies
of state government.
8. In deciding upon the wisdom and propriety of granting any
such applications, and the priority that should be given to them,
consideration should be given to the aeronautical policy of the
state in question, with reference to such matters as the state’s
policy in protecting the approaches to airports; the state’s policy
in respect to the employment of any taxes collected on the fuel
used in aircraft; and any measures taken by the state to insure
the proper maintenance of airports and the maintenance of reasonable charges for the services given them.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
9. The detailed plans for the location and development of any
airport with respect to which there is federal contribution of
any kind, should be subject to the approval of the federal
agency charged with the establishment of civil airways, landing areas, and necessary air navigation facilities.
10. There should be no direct federal contribution to the cost of
maintaining airports, other than federal airports; except that
the administrator of the Civil Aeronautics Authority may, in
accordance with the Civil Aeronautics Act and so far as available funds permit, assume the cost of operating any lighting
equipment and other air navigation facility as a part of the
cost of operation of the federal airways system.
The airport survey submitted in 1939 was updated with new
studies completed in 1940. Continuing studies were made through
the war years. While first importance was attached to the military
requirements, care was taken whenever possible to anticipate the
needs of postwar civil aviation. During the war years the federal government, through the CAA, spent $353 million for the development
of military landing areas in the continental United States. This does
not include funds spent by the military agencies. During the same
period the CAA spent $9.5 million for the development of landing
areas in the United States solely for civil purposes.
Federal Airport Act of 1946
At the end of World War II, over 500 airports constructed for the
military by the CAA were declared surplus and were turned over to
cities, counties, and states for airport use. The interest in adequate
airport facilities by various political subdivisions of government
continued. The needs were made known to Congress by various
interests. As a result, the House of Representatives passed a resolution (H.R. 598, 78th Congress) directing the CAA to make a survey of
“need for a system of airports and landing areas throughout the
United States” and report back to Congress.
The results of this survey were completed in 1944 (House Document 807, 78th Congress, 2nd Session) and contained the following
principal recommendations:
1. That Congress authorize an appropriation to the Office of the
Administrator of Civil Aeronautics not to exceed $100 million
annually to be used in a program of federal aid to public
agencies for the development of a nationwide system of
public airports adequate to meet the present and immediate
future needs of civil aeronautics. The administrator be
authorized to allocate such funds for any construction work
involved in constructing, improving, or repairing an airport,
including the construction, alteration, and repair of airport
21
22
Airport Planning
buildings other than hangars, and the removal, lowering,
marking, and lighting of airport obstructions; for the acquisition of any lands or property interest necessary either for
any such construction or to protect airport approaches; for
making field and specifications; supervising and inspecting
construction work, and for any necessary federal expenses
in the administration of this program.
2. That such a program can be conducted in cooperation with
the state and other nonfederal public agencies on a basis to be
determined by the Congress. That the federal contribution be
determined by the Congress in passing the necessary enabling
legislation. A good precedent for the proportionate sharing of
costs exists in the public-roads program which has operated
satisfactorily for many years on a 50-50 basis.
3. That any project for which federal aid is requested must meet
with the approval of the administrator of Civil Aeronautics as
to scope of development and cost, conform to Civil Aeronautics Administration standards for location, layout, grading,
drainage, paving, and lighting and all work thereon be subject to the inspection and approval of the Civil Aeronautics
Administration.
4. In order to participate in the federal-aid program, a state shall
a. Establish and empower an official body equipped to conduct its share of the program.
b. Have legislation adequate for the clearing and protection
of airport approaches, and such other legislation as may
be necessary to vest in its political subdivisions all powers
necessary to enable them to participate through the state
as sponsors of airport projects.
c. Have no special tax on aviation facilities, fuel, operations,
or businesses, the proceeds of which are not used entirely
for aviation purposes.
d. Ensure the operation of all public airports public interest,
without unjust discrimination or unreasonable charges.
e. Ensure the proper operation and maintenance of all public
airports within its jurisdiction.
f. Make airports developed with federal aid available for
unrestricted use by United States government aircraft
without charge other than an amount sufficient to cover
the cost of repairing damage done by such aircraft.
g. Require the installation at all airports for which federal
funds have been provided for a standard accounting and
fiscal reporting system satisfactory to the administrator.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
5. That sponsors of projects be required to enter into contracts
with the Civil Aeronautics Administration ensuring the
proper maintenance and protection of airports developed
with federal aid and their operation in the public interest.
The recommendations contained in the airport needs survey
report were written into an airport development bill, introduced into
the House of Representatives (H.R. 5024) but no action was taken on
it. After extensive hearings in both houses of Congress, the Senate
passed an airport bill (S. 2) in 1945 and later that year the House
passed a bill (H.R. 3615). The language in these two bills differed in
several respects. One of the principal differences was the method
employed in channeling funds to the municipalities. The Senate bill
provided that funds be channeled to the municipalities through
appropriate state aviation organizations unless a state did not have
an appropriate agency to handle the matter. The House bill permitted
channeling of funds either through the state or directly to a municipality or other political subdivision of government. The substitute
bill agreed to in conference conformed more nearly to the House language. Another difference had to do with the size of the discretionary
fund, which, instead of being apportioned among the states by a fixed
formula, would be available for use by the administrator at his sole
determination. The House bill provided 25 percent of the total appropriation for airport development as a discretionary fund, the Senate
bill 35 percent. The compromise reached in conference retained the
House version. Other differences which were worked out in conference concerned whether or not the costs of the acquisition of land and
interest in airspace should be eligible for federal aid, project sponsorship requirements, and the reimbursement for damage to public airports caused by federal agencies.
The conference report was approved by the Congress and the
Federal Airport Act of 1946 was enacted (Public Law 79-377). Known
as the Federal Airport-Aid Program, appropriations of $500 million
over a 7-year period were authorized for projects within the United
States plus $20 million for projects in Alaska, Hawaii, Puerto Rico,
and the Virgin Islands. In l950, the 7-year period was extended an
additional 5 years (Public Law 81-846). However, annual appropriations approved by Congress were much less than the amounts authorized by the act.
The original act provided that a project shall not be approved for
federal aid unless “sufficient funds are available for that portion of
the project which is not to be paid by the United States.”
Local governments often required 2 to 3 years to make arrangements for raising funds. Most of the larger projects are financed
locally through the sale of bonds. This method of financing requires
legislation at the local level and, in some cases, also at the state level.
General obligation bonds normally require approval by the electorate.
23
24
Airport Planning
Programs to inform the public on the needs for airport improvement
must be carefully planned and executed. Thus, after the completion
of these events, local governments frequently found that sufficient
federal funds were not appropriated to match local funds, and the
projects were delayed. Another complaint of local governments had
been that Congress failed to fulfill its obligation, since the amount
appropriated by Congress fell far short of the amount authorized by
the Federal Airport Act. These deficiencies as well as other matters
were incorporated in a bill (S. l855). Hearings on the bill were held
before the subcommittee of the Committee on Interstate and Foreign
Commerce of the United States Senate in l955. Representatives of the
Council of State Governments, the American Municipal Association, the
National Association of State Aviation Officials, airport and industry
trade associations, and individuals were unanimous in the feeling
that air transportation had reached a stage of maturity where many
airports were woefully inadequate and greater financial assistance
from the federal government would be required to meet the current
needs of aviation. After much debate, the bill was approved by the
President (Public Law 84-211).
This amending act made no change in the basic policies and purposes expressed in the original act. There were no changes in the
requirements with respect to the administration of the grants authorized, such as the distribution and apportionment of funds, the eligibility of the various types of airport construction, sponsorship
requirements, etc. The primary purpose of the act was to substitute
for the procedure of authorizing annual appropriations for airport
projects, provisions granting substantial annual contract authorization in specific amounts over a period of four fiscal years. Airport
sponsors were thus furnished assurance that federal funds would be
available at the time projects were to be undertaken.
This law provided $40 million for fiscal year l956 and $60 million
for each of fiscal years l957, l958, and l959 for airport construction in
the continental United States. It also provided $2.5 million in fiscal
year l956 and $3 million for the three succeeding fiscal years for airport construction in Alaska, Hawaii, Puerto Rico, and the Virgin
Islands. Besides the $42.5 million made available in fiscal year l956 by
Public Law 84-2ll, Congress approved an additional appropriation of
$20 million for airport projects.
Federal Aviation Act of 1958
For a number of years there had been a growing concern about the
division of responsibility in aviation matters among different agencies of the federal government. Unlike highway or other forms of
transport, aviation is unique in its relation to the federal government.
It was historically the only mode whose operations are conducted
almost wholly within federal jurisdiction, and one subject to little or
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
no regulation by states or local authorities. Thus, the federal government bears virtually complete responsibility for the promotion and
supervision of the industry in the public interest. The military interest and the entire national defense concept are also intimately related
to aviation.
Recognizing that the demands on the federal government in the
years ahead would be substantial, the director of the Bureau of the
Budget requested a review of aviation-facilities problems in 1955. A
report was issued later that year recommending that a study of “longrange needs for aviation facilities and aids be undertaken” and that
such a study be made under the direction of an individual of national
reputation.
President Dwight D. Eisenhower accepted these recommendations and appointed Edward P. Curtis as his Special Assistant for
Aviation Matters in 1957. Curtis was charged with the responsibility
of preparing a comprehensive aviation-facilities plan which would
“provide the basis for the timely installation of technically adequate
aids, for optimum coordination of the efforts of the civil and military
departments, and for effective participation by state and local authorities and the aircraft operators in meeting facilities requirements.”
Curtis completed his report and submitted it to the President. In this
report Curtis stated that “it has become evident that the fundamental
reason for our previous failures lies with the inability of our governmental organizations to keep pace with the tremendous growth in
private, commercial, and military aviation which has occurred in the
last 20 years.” Curtis recommended the consolidation of all aviation
functions, other than military, into one independent agency responsible only to the President. However, the report recognized that to
“develop new management structures and policy, to coordinate proposals within the executive branch and to obtain legislation implementing a new permanent organization might be as long as 2 or
3 years.” The most urgent matter requiring attention was in the area
of air traffic control. The collision of two aircraft over the Grand
Canyon in 1956 provided the impetus for rapid legislative action for
remedying midair collisions. Curtis recommended that, as an interim
measure, there be created an Airways Modernization Board whose
function was to “develop, modify, test, and evaluate systems, procedures, facilities, and devices, as well as define the performance characteristics thereof, to meet the needs for safe and efficient navigation
and traffic control of all civil and military aviation except for those
needs of military agencies which are peculiar to air warfare and primarily of military concern, and select such systems, procedures, facilities, and devices which will best serve such needs and will promote
maximum coordination of air traffic control and air defense systems.”
The board was to consist of the Secretary of Commerce, the Secretary
of Defense, and an independent chairman.
25
26
Airport Planning
Congress was receptive to this recommendation and passed the
Airways Modernization Act of 1957 (Public Law 85-133) establishing
the board for a 3-year term.
In the meantime, there were more midair collisions and reports of
near misses were given wide circulation. Costly disagreements
between the CAA and the military on the type of navigational aids to
be used on the airways no doubt also spurred Congressional action.
As a result, instead of taking 2 or 3 years to create a single aviation
agency as was predicted, the Congress acted favorably on the legislation within a year of the passage of the Airways Modernization Act.
This legislation is known as the Federal Aviation Act of 1958 (Public
Law 85-726). This law superseded the Civil Aeronautics Act of 1938
but not the Federal Airport Act of 1946.
The principal provisions of the law insofar as organizational
changes were concerned are as follows:
1. The Federal Aviation Agency was created as an independent
agency with an administrator directly responsible to the
President. The agency incorporated the functions of the Civil
Aeronautics Administration and the Airways Modernization
Board, both of which were abolished.
2. The Civil Aeronautics Board was retained as an independent agency including all its functions except its safety
rule-making powers, which were transferred to the Federal
Aviation Agency.
Creation of the U.S. Department of Transportation
For many years it had been argued that there had been a proliferation of
federal activities with regard to transportation. For example, the Bureau
of Public Roads was part of the Department of Commerce whereas the
Federal Aviation Agency was an independent agency. It was felt by different transport interests that there was a lack of coordination and effective administration of the transportation programs of the federal government resulting in a lack of a sound national transportation policy. It
is interesting to note that the first legislative proposal in this direction
dates back to 1874. However, in recent years, the involvement of the
federal government in the development of the transportation systems
of the nation has been enormous, requiring much more coordination
among federal transport activities than ever before. With this as a background, a Cabinet-level Department of Transportation (DOT) was created headed by the Secretary of Transportation (Public Law 89-670). The
department began to function on April 1, 1967.
The agencies and functions transferred to the Department of
Transportation related to air transportation included the Federal
Aviation Agency in its entirety and the safety functions of the Civil
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Aeronautics Board, including the responsibility for investigating and
determining the probable cause of aircraft accidents, and its appellate
safety functions involving review on appeal of the suspension, modification, or denial of certificates or licenses. The name of the Federal
Aviation Agency was changed to the Federal Aviation Administration
(FAA). The administrator is still appointed by the President but
reports directly to the Secretary of Transportation.
A National Transportation Safety Board (NTSB) was established
by the same act which created the Department of Transportation to
determine “the cause or probable cause of transportation accidents
and reporting the facts, conditions, and circumstances relating to
such accidents” for all modes of transportation. Although created
by the act which established the DOT, the board in carrying out its
functions is “independent of the secretary and other offices and officers of the department.” The board consists of five members appointed
by the President and annually reports directly to Congress.
The creation of the DOT did not alter any legislation in the Federal
Aviation Act of 1958, with the exception of the transfer of the safety functions from the Civil Aeronautics Board to the National Transportation
Safety Board. In the act of establishing the new department, however,
there was a statutory requirement to establish an Office of Noise Abatement to provide policy guidance with respect to interagency activities
related to the reduction of transportation noise. With the introduction of
jet aircraft in 1958 the complaints against aircraft noise increased significantly. As a result, in 1968 the Federal Aviation Act was amended by
Congress (Public Law 90-411) to require noise abatement regulations. Its
principal purpose was to establish noise levels which aircraft manufacturers cannot exceed in the development of new aircraft.
Airport and Airway Development Act of 1970
In the mid-1960s, as air traffic was expanding at a fairly rapid pace,
air traffic delays getting into and out of major airports began to
increase rapidly. Along with the delays in the air, congestion was also
taking place on the ground in parking areas, on access roads, and in
terminal buildings. It was evident that to reduce congestion substantial financial resources would be required for investment in airway
and airport improvements. For airports alone it was estimated that
$13 billion in new capital improvements would be required for public
airports in the period 1970 to 1980. The amount of money authorized
by the Federal Airport Act of 1946 was insufficient to assist in financing such a vast program. The normal and anticipated sources of revenue available to public airports were also not sufficient to raise the
required funds for capital expenditures. It was argued that much of
the congestion in the air at major airports was due to a lack of funds
to modernize the airways system. Funds for airport development
came from the budget of the FAA authorized by Congress each year
27
28
Airport Planning
and not from the Federal Airport Act. The deficiencies in airport and
airway development were documented in several reports. It was the
consensus of industry and government that the only way to provide
the funds needed for airports and airways was through increased or
new taxes imposed upon the users of the air transport system. It was
also argued that the revenues from these taxes should be specifically
earmarked for aviation and not go to the general fund. The concept of
establishing a trust fund similar to that of the national highways program was agreed upon. Finally after much debate in Congress, the
Airport and Airway Development Act of 1970 and the Airport and
Airway Revenue Act of 1970 were enacted (Public Law 91-258).
As finally passed, the act was divided into two sections: Title I
detailed the airport assistance programs and established a financing
program for airport grants, airways hardware acquisition, and
research and development; Title II created the Airport and Airway
Trust Fund and established the pattern of aviation excise taxes which
would provide the resources upon which the Title I capital programs
would depend through 1980. The excise taxes adopted consisted of a
tax on domestic passenger tickets, a head tax on international passenger departures, a flowage tax on all fuel used by general aviation,
and tax on all air cargo waybills. In addition, an annual aircraft registration tax was levied on all aircraft (commercial and general aviation) plus an annual weight surtax for all aircraft weighing in excess
of 2500 lb. Finally, revenues from existing taxes on aircraft tires and
tubes were transferred from the Highway Trust Fund to the Airport
and Airway Trust Fund.
The amount of these excise taxes were changed in the Omnibus
Budget Reconciliation Act of 1990 (Public Law 101-508) and currently
consists of a 10 percent tax on domestic passenger tickets, a $6 head
tax on international passenger departures, a 17.5 cents a gallon flowage tax on all fuel used by general aviation, and a 6.25 percent tax on
all air cargo waybills.
Significant changes from the Federal Airport Act were as follows:
l. The provision of funds to local agencies for airport system
planning and master planning
2. The emphasis on airports served by air carriers and general
aviation airports to relieve congested air carrier airports
3. The provision of funds for commuter service airports
4. The requirement that the FAA issue airport operating certificates to ensure that airports were adequately equipped for
safe operations
5. Provision of requirements to ensure that airport projects did
not adversely affect the environment and were consistent
with long-range development plans of the area in which the
project was proposed
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
6. Provision for terminal facility development in non-revenue
producing public areas
7. The requirement that the FAA develop a National Airport
System Plan (NASP)
To be eligible for federal aid, airport ownership was required to
be vested in a public agency and the airport must be included in the
NASP. This plan was reviewed and revised as necessary to keep it
current. It was prepared by the FAA and submitted to Congress by
the Secretary of Transportation. The plan specified, in terms of general location and type of development, the projects considered necessary to provide a system of public airports adequate to anticipate and
meet the needs of civil aeronautics. These projects included all types
of airport development eligible for federal aid under the act and were
not limited to any classes or categories of public airports. The plan
was based on projected needs over 5- and 10-year periods.
Because of the mounting public concern for the enhancement of
the environment, the act specifically stated that authorized projects
provide for the protection and enhancement of the natural resources
and the quality of the environment of the nation. The Secretary of
Transportation was required to consult with the Secretary of the Interior and the Secretary of Health, Education and Welfare regarding the
effect of certain projects on natural resources and whether “all possible steps have been taken to minimize such adverse effects.” The Act
required that airport sponsors provide the “opportunity for public
hearings for the purpose of considering the social, economic, and
environmental effect on any project involving the location of an airport, the location of a runway, and a runway extension.” In addition,
the National Environmental Policy Act of 1969 (Public Law 91-190),
supported by a Presidential Executive Order (11514, March 5, 1970),
required the preparation of detailed environmental impact statements for all major airport development actions significantly affecting the quality of the environment. The environmental impact statement was required to include the probable impact of the proposed
project on both the human and natural environment, including impact
on ecological systems such as wildlife, fish, and marine life, and any
probable adverse environmental effects which could not be avoided
if the project was implemented. The Act also stipulated that no airport
project involving “airport location, a major runway extension, or runway location” could be approved for federal funding unless the governor of the state in which the project was located certified to the
Secretary of Transportation that there was reasonable assurance that
the project would comply with applicable air and water quality
standards. Finally the project had to be consistent with the plans of
other agencies for development of the area, and the airport sponsor
had to assure the government that adequate housing was available
for any displaced people. The Aviation Safety and Noise Abatement
29
30
Airport Planning
Act of 1979 (Public Law 96-193) amended this legislation to place
increased emphasis on reducing the noise impacts of airports. Thus
one of the principal differences between the Federal Airport Aid Program and the Airport Development Aid Program was the emphasis
on environmental protection in the latter.
The Airport and Airway Development Act made no mention concerning specific standards for determining airports to be included in
the National Airport System Plan. It did state, however, that
The Plan shall set forth, for at least a ten-year period, the type and estimated cost of an airport development considered by the Secretary to be
necessary to provide a system of public airports adequate to anticipate
and meet the needs of civil aeronautics, to meet the requirements in
support of the national defense as determined by the Secretary of
Defense, and to meet the special needs of the Postal Service. In formulating and revising the plan, the Secretary shall take into consideration,
among other things, the relationship of each airport to the rest of the
transportation system in the particular area, to the forecasted technological developments in aeronautics, and to developments forecasted in
the other modes of transportation.
With this and other policy guidelines, the FAA developed entry
criteria which described a broad and balanced airport system. The
1980 NASP, for example, included about 3600 airport locations, indicating that the federal interest in developing a basic airport system
extended well beyond the major airports with scheduled airline service. In an effort to provide a safe and adequate airport for as many
communities as possible, NASP criteria were developed to include
the general aviation airports which serve smaller cities and towns.
The NASP airport entry criteria evolved from both policy and
legislative considerations and focused on two broad categories of airports, those with scheduled service and those without significant
scheduled service in the general aviation and reliever category. Airports with scheduled service were included in NASP because of their
use by the general public, legislative provisions which specifically
designated airports to receive development funds, and their use by
CAB certified carriers. Commuter airports were identified in NASP
starting in 1976, when legislation was enacted which designated them
as a type of air carrier airport and provided them with special development funds. About 70 percent of the airports in the NASP were
general aviation locations which met the criteria of viability because
of the number of based aircraft or aircraft activity, and which provided reasonable access for aircraft owners and users to their community. Reliever airports have been included as a separate NASP
category since the 1960s when Congress designated special funding
for the purpose of relieving congestion in large metropolitan areas by
providing additional general aviation capacity.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
Airline Deregulation Act of 1978
The Airline Deregulation Act (Public Law 95-504) was passed by
Congress in October 1978. This legislation eliminated the statutory
authority for the economic regulation of the passenger airline industry in the United States. It provided that the Civil Aeronautics Board
would be abolished in 1985. The legislation was intended to increase
competition in the passenger airline industry by phasing out federal
authority to exercise regulatory controls during the period of time
between 1978 and 1985. The principal provisions of this legislation:
1. Required the CAB to place maximum reliance on competition
in its regulation of interstate airline service, while continuing
to ensure the safety of air transportation; to maintain service
to small communities; and to prevent practices which were
deemed anticompetitive in nature.
2. Required CAB approval of airline acquisitions, consolidations, mergers, purchases, and operating contracts; the burden to prove that an action was anticompetitive in nature was
placed upon the party challenging that action.
3. Permitted carriers to change rates within a range of reasonableness from the standard industry fare without prior CAB
approval; the CAB was authorized to disallow a fare change
if it considered the change predatory.
4. Provided interstate carriers an exemption from state regulation of rates and routes.
5. Required the CAB to authorize new routes and services that
were consistent with the public convenience and necessity.
6. Allowed carriers to be granted operating rights to any route
on which only one other carrier was providing service and on
which other airlines were authorized to provide service but
were not actually providing a minimum level of service. If
more than one airline was providing service on this route, the
CAB was required to determine if the granting of additional
route authority was consistent with the public convenience
and necessity before allowing additional carriers to service
the route. An airline not providing the specified minimum
level of service on a route (dormant authority) could begin
providing such service and retain its authority. Otherwise,
the CAB was required to revoke the unused authority.
7. Provided for an automatic market entry program, whereby
airlines could begin service on one additional route each year
during the period 1979 to 1981 without formal CAB approval.
Each carrier was also permitted to protect one of its existing
routes each year by declaring it as ineligible for automatic
market entry by another airline.
31
32
Airport Planning
8. Authorized the CAB to order an airline to continue to provide “essential air transportation service” and, for a 10-year
period, to provide subsidies or seek other willing carriers to
ensure the continuation of essential service.
9. Required the CAB to determine within 1 year of the enactment of the legislation what it considered to be “essential air
transportation service” for each point being serviced at the
time of enactment of the legislation.
10. Required the CAB and the Department of Transportation to
determine mechanism by which the state and local governments should share the cost of subsidies from the federal government to preserve small community air service and to make
policy recommendations to Congress on this matter.
11. Exempted from most CAB regulation commuter aircraft
weighing less than 18,000 lb and carrying fewer than
56 passengers.
12. Made commuter and intrastate air carriers eligible for the
federal loan guarantee program.
13. Provided that the domestic route authority of the board
would cease in 1981; its authority over domestic fares, acquisitions, and mergers would cease in 1983; and the board
would be abolished (sunset) in 1985.
14. Provided that after the board was abolished, the local service
carrier subsidy program was to be transferred to the Department of Transportation; the foreign air transportation authority of the board was to be transferred to the Transportation
and Justice Departments, in consultation with the State
Department; and the mail subsidy program was to be transferred to the U.S. Postal Service.
Impact of Airline Deregulation
In the United States prior to 1978, air carriers applied to the Civil
Aeronautics Board (CAB) for permission to serve markets. The CAB
granted air carriers service to markets with a determined operating
and fare schedule. Upon deregulation, air carriers freely entered new
markets, increasing the number of markets served, increasing competition and lowering overall airfares. To maximize their market share in
the industry, several air carriers concentrated their route structures on
one or more “hub” airports. The early years of this hub and spoke
route system resulted in the greatest growth in commercial aviation in
its history. The beginning of the twenty-first century exposed many of
the weaknesses in the airline hub and spoke model, including the
increased costs of operating through congested hub airports, increasing fuel and other operating expenses, combined with the ability for
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
the public to use the Internet to avoid extraordinarily high full fares
thereby reducing the overall revenue stream of the airlines. The air
carriers dependent on their traditional “legacy” business models fell
into serious financial distress, and combined with the short-term drop
in air travel demand following the terrorist attacks of September 11,
2001, many fell into bankruptcy to emerge under more efficient business models years later.
These more efficient business models were based on the emergence of “low-cost carriers” or LCCs, that operate primarily on a
market-based origin to destination route network and price fares relative to operating costs, rather than solely by passenger demand. The
LCC airline model has been the largest growth segment of the domestic airline industry in the United States.
The Airport and Airway Improvement Act of 1982
In 1982, Congress enacted the Airport and Airway Improvement Act
(Title V of the Tax Equity and Fiscal Responsibility Act of 1982, Public
Law 97-248). This act continued to provide funding for airport planning and development under a single program called the Airport
Improvement Program (AIP). The Act also authorized funding for
noise compatibility planning and implementing noise compatibility
programs contained in the Noise Abatement Act of 1979 (Public Law
96-193). It required that to be eligible for a grant the airport must be
included in the National Plan of Integrated Airport Systems (NPIAS).
The NPIAS, the successor to the National Airport System Plan
(NASP), is prepared by the FAA and published every 2 years and
identifies public use airports considered necessary to provide a safe,
efficient, and integrated system of airports to meet the needs of civil
aviation, national defense, and the postal service.
The Airport and Airway Improvement Act has been amended
several times resulting in significant changes in the provisions of the
act and in the appropriations authorized under the Act. These
amendments are included in the Continuing Appropriations Act of
1982 (Public Law 97-276), the Surface Transportation Assistance Act
(Public Law 97-424), the Airport and Airway Safety and Capacity
Expansion Act of 1987 (Public Law 100-223), the Airway Safety and
Capacity Expansion Act of 1990 (Public Law 101-508), and the Airport and Airway Safety, Capacity, Noise Improvement and Intermodal Transportation Act of 1992 (102nd Congress H.R. 6168).
This legislation, as amended, significantly increased the level of
federal funding for airports to an aggregate total of more than
$14 billion for the period from 1982 through 1992.
The Aviation Safety and Capacity Act of 1990
In response to issues concerning the provision of limited AIP funds to
the largest airports, thereby leaving the smaller airports with little in
33
34
Airport Planning
capital improvement funding support, in 1990, Congress passed the
Aviation Safety and Capacity Expansion Act. This act established the
policy of allowing airports to impose a passenger facility charge (PFC)
to supplement their capital improvement programs, while allowing
greater amounts of AIP funding to be allocated to smaller airports
with capital improvement needs. Under this Act, an airport applied to
collect a $1, $2, or $3 charge, on any passenger enplaning at the airport. The fee would be collected by the air carriers, upon purchase of
a ticket. Revenues generated by PFCs would then be spent by the
airport that generated the revenue on allowable costs associated with
certain capital improvement projects approved by the FAA that
enhance safety, security, or capacity, or increase air carrier competition. In 2001, the maximum allowable PFC was raised to $4.50. As of
June 2007, approximately $58.6 billion in PFCs have been collected at
367 airports nationwide. More than 1500 projects utilizing PFC revenues have been approved since the 1990 Aviation Safety and Capacity
Expansion Act introduced the PFC program.
AIR-21: The Wendell Ford Aviation Investment Act
for the 21st Century
In April 2000, funding for airport planning and design through the
AIP and PFC programs was increased with the Wendell H. Ford Aviation Investment and Reform Act for the Twenty-First Century, known
as AIR-21 (Public Law 106-181). This funding increase was designed
to assist larger airports which have become highly congested, as well
as smaller airports struggling to preserve commercial air service.
The AIR-21 Act was introduced at a time when the nation’s air
carriers were coming off record profits and growth in air transportation was at its highest in history. As part of the act, AIP funding was
increased, on the order of 300 percent to many airports to allow for
capital improvement projects designed to relieve the increased congestion and delays encountered at the nation’s largest airports at the
end of the 1990s.
The Aviation and Transportation Security Act of 2001
In response to the terrorist attacks involving the hijacking of four U.S.
airliners used in suicide attack missions on Washington, D.C. and
New York City, on September 11, 2001, The Aviation and Transportation Security Act (Public Law 107-071) was signed into law. This Act
created the Transportation Security Administration (TSA), which
took authority over aviation security and imposed a series of requirements for screening air carrier passengers and luggage including
mandatory electronic inspection of all checked luggage. This has had
profound effects on airport terminal planning and design. To fund
these policies, the Act authorized a passenger surcharge of $2.50 per
flight segment and a fee imposed to air carriers equivalent to each
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
airline’s costs of providing passenger security screening in the year
2000. These funds are collected by air carriers through ticket purchases and are used to fund the operation of the TSA and to contribute to airport development to accommodate enhanced security policies and procedures.
Vision 100 Century of Aviation Act of 2003
The AIR-21 Act authorized AIP funding through 2003 at which time
reauthorization legislation was to occur. This reauthorization of AIP
funding was accomplished with the Vision 100 Century of Aviation
Act (Public Law 108-176) in December 2003. The purpose of the Vision
100 Act was to further increase, yet diversify, federal funding for airport and airspace improvements as the commercial air carrier industry recovers, and restructures, from the severe economic industry
downturns following the September 11, 2001 attacks, and other economic and geopolitical issues. The act increased annual AIP authorizations to approximately $3.4 billion in 2004, up to $3.7 billion in
2007, the last year of the act’s term and broadened the use of AIP and
PFC funds to include airport improvements that have certain environmental benefits, investments to attract air service to underutilized
airports, and to fund debt-service for projects previously funded
through bond issuances.
NextGen Financing Reform Act of 2007/
FAA Reauthorization Act of 2009
The financial recovery the nation’s airlines combined with increases
in general aviation activity have begun to put increased strains on an
aging air traffic control system and debates in Congress ensued
regarding how to appropriately reauthorize funding for civil aviation
as the terms of Vision 100 were due to expire in 2007. The Congress
debate focused around a complete restructuring of the current funding programs, including major AIP reform. Rather than a system of
funding airport and air traffic management through airline passenger,
cargo, and fuel taxes, an aircraft-based user fee system was introduced to Congress for debate. This new legislation will be the first to
implement fees directly on commercial and general aviation operations using the busiest areas of the national airspace system.
The NextGen Financing Reform Act focused funding on creating
the Next Generation Air Traffic Management System to replace nearly
50-year-old air traffic control technology.
As of the end of 2007, the NextGen Financing Reform Act of 2007
had yet to be signed into law. Two versions of the act are being
debated in Congress. The version supported by the House of Representatives (H.R. 2881) supports reauthorizing funding by increasing
fuel taxes on general aviation fuel to between 24.1 and 35.9 cents per
gallon, while maintaining the remaining tax structure implemented
35
36
Airport Planning
in Vision 100. The version of the act in the Senate (S. 1300) proposes a
user-based approach, including a per-flight surcharge of $25 for “air
traffic control costs,” for general aviation jet and turbo-prop aircraft
operating inside of controlled airspace.
The NextGen Financing Reform Act of 2007 was ultimately discarded with the new presidential administration in 2009. In March
2009, a new reauthorization bill, the FAA Reauthorization Act of 2009,
was introduced as H.R. 915. As of publication of this text there is continued debate on how the federal government of the United States
will fund the modernization of the national airspace system, particularly in the face of the economic downturn of beginning in late 2007.
The focus of debate has continued to be around the potential implementation of user-based fees and other such taxes that may prohibit
growth. The funding of the nation’s aviation system continues to be a
critical and highly debated topic.
State Roles in Aviation and Airports
State interest in aviation began as early as 1921, when the state of
Oregon established an agency to handle matters concerning aviation.
Since that time virtually all states have established aeronautical agencies either as commissions, departments, bureaus, boards, or divisions. Their responsibilities vary considerably and include channeling
federal aid funds, planning state airport systems, providing state aid
to local airport authorities, constructing and maintaining navigational equipment, investigating small aircraft accidents, enforcing
safety regulations, and licensing airports.
Despite the growing concern of the states in airport development
and aviation planning, their participation in the past has had little
resemblance to the pattern associated with highway development.
The states have always played a leading role in the development of
roads and streets within their boundaries, whereas in airport development this has not been true. The reason for this pattern can best be
explained by looking into the background of the entry of the states
into aviation.
The majority of airports for civil aviation served by air carriers
are municipally owned and operated. In a large number of states
these airports were in operation prior to the formation of a state aeronautical agency. From its inception air transportation, because it is
inherently of an interstate nature, became a matter of federal concern.
The federal government provided much technical and financial
assistance to municipalities. During World War II a great number of
municipalities were the recipients of federal aid from the Civil Aeronautics Administration through the Defense Landing Area Program.
Thus, in the early stages of airport development in this country, a fairly
close relationship was established between the federal government
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
and the municipalities. This relationship was furthered when the
Federal Airport Act of 1946 authorized the CAA to issue grants
directly to municipalities, as long as such a procedure was not
opposed to state policy. In the meantime, the majority of states were
doing very little in the way of providing funds to municipalities for
airports. While significant increases in state aid for airport development have occurred in the last several years, the amount of federal
aid has been substantially higher.
States such as Alaska, Rhode Island, and Hawaii directly own
and operate many of the airports within their respective boundaries.
Other states support municipality-owned airports through state
block grant funding programs. In those states where monetary aid is
made available for airport development, the plans, specifications,
and design for airport construction are generally reviewed by the
state aeronautical agency.
There is no doubt that participation by the states in airport development is assuming a more significant role with the emergence of
recent legislation in Congress to channel funds directly to state aeronautical agencies through block grant programs. The public concern
for environmental control has resulted in legislation being passed at
the state level, in addition to federal statutes, aimed at the control of
aircraft noise and pollution. As general aviation and commuter activities continue to grow, the states will have to share the burden with
the federal government in providing facilities for these activities,
enforcing safety regulations, and other matters.
Aviation Organizations and Their Functions
The organizations directly involved in United States and international air carrier transportation and general aviation activity have an
important influence on airport development as well as aircraft operations. These organizations and their functions can be classified into
four groups, namely, federal agencies, state agencies, international
government agencies, and industry or trade organizations.
Federal Agencies of the United States Government
There are several agencies at the federal level which dictate policy of
direct and indirect effects on air transportation. The Federal Aviation
Administration (FAA), the Transportation Security Administration
(TSA), and the Environmental Protection Agency (EPA) are those
agencies with the most direct influence on civil aviation policy, and
airport planning and design.
Federal Aviation Administration
The Federal Aviation Administration is the agency within the U.S.
Department of Transportation responsible for the safe and efficient
37
38
Airport Planning
operation of the nation’s civil aviation system. The FAA is headed by
the chief executive known as the administrator who is appointed by
the President. The FAA performs the following functions:
1. Encourages the establishment of civil airways, landing areas,
and other air facilities
2. Designates federal airways and acquires, establishes, operates, and conducts research and development and maintains
air navigation facilities along such civil airways
3. Makes provision for the control and protection of air traffic
moving in air commerce
4. Undertakes or supervises technical development work in the
field of aeronautics and the development of aeronautical
facilities
5. Prescribes and enforces the civil air regulations for safety
standards, including:
a. Effectuation of safety standards, rules, and regulations
b. Examination, inspection, or rating of airmen, aircraft
engines, air navigation facilities, aircraft, and air agencies
c. Issuance of various types of safety certificates
6. Provides for aircraft registration
7. Requires notice and issues orders with respect to hazards to
air commerce
8. Issues airport operating certificates to airports serving air
carriers
The FAA develops, directs, and fosters the coordination of a
national system of airports, the National Plan of Integrated Airport
Systems [22], an aviation system capacity enhancement plan, the
Aviation System Capacity Plan [9], a plan to modernize and significantly upgrade the air traffic control system, the National Airspace
System Plan [21], and oversees funding for airports through the Airport Improvement Program and PFC Program. In this connection it
performs the following functions:
1. Provides consultation and advisory assistance on airport
planning, design, construction, management, operation, and
maintenance to governmental, professional, industrial, and
other individuals and agencies.
2. Develops and establishes standards, government planning
methods and procedures; airport and seaplane base design
and construction; and airport management, operation, and
maintenance.
3. Collects and maintains an accurate record of all available airport facilities in the United States.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
4. Directs, formulates, and keeps current a national plan (NPIAS)
for the development of an adequate system of airports in
cooperation with federal, state, and local agencies, and determines and recommends the extent to which portions or units
of that system should be developed or improved.
5. Develops and recommends principles, for incorporation in
state and local legislation, to permit or facilitate airport development, regulation, and protection of approaches through
zoning or property acquisition.
6. Secures compliance with statutory and contractual requirements relative to airport operation practices, conditions, and
arrangements.
7. Develops and recommends policies, requirements, and procedures governing the participation of states, municipalities, and
other public agencies in federal-aid airport projects and secures
adherence to such policies, requirements, and procedures.
As illustrated in Fig. 1-6, the FAA is organized into a number of
offices within its headquarters in Washington, D.C. The offices most
directly related to airport planning and development are the Office of
Airport Planning and Programming, the Office of Airport Safety and
Standards. In addition to Headquarters Offices, the FAA is divided
into nine Airports Regional Offices, as illustrated in Fig. 1-7. Within
these Regional Offices are Airports District Offices (ADOs). It’s within
these ADOs where specific consultation between the FAA and airport
planners on airport planning and design programs are primarily discussed, analyzed, and ultimately approved.
The FAA publishes most of the regulations of concern to civil
aviation and these—are found in Title 14—“Aeronautics and Space”
of the United States Code of Federal Regulations. The Federal Aviation Regulations (FARs) are made up of more than 100 chapters,
known as “parts,” regulating various aspects of the civil aviation system, including pilots, aircraft, the airspace system, and airports. The
FARs of most concern to airport planning and design that will be further discussed in this text include
FAR Part 1: Definitions and Abbreviations
FAR Part 11: General Rule Making Procedures
PAR Part 36: Noise Standards: Aircraft Type and Airworthiness
Certification
FAR Part 71: Designation of Class A, Class B, Class C, Class D, and
Class E Airspace Areas, Airways, Routes, and Reporting Points
FAR Part 73: Special Use Airspace
FAR Part 77: Objects Affecting Navigable Airspace
FAR Part 91: General Operating and Flight Rules
39
40
Airport Planning
Federal Aviation Administration
As of October 23, 2006
Chief of Staff
Administrator
Center for Early
Dispute Resolution
Deputy
Administrator
Office of
the Civil
Rights
Office of
Chief
Counsel
Office of
Govt. &
Industry
Affairs
Office of
Communications
ACR
AGC
AGI
AOC
Assistant
Adm. for
Region and
Center
Operations
Assistant
Adm. for
Aviation Policy,
Planning &
Environment
ARC
Assistant
Adm. for
Information
Services
AEP
Chief Operating Officer,
Air Traffic Organization
(ATO)
AJO
AOA
JPDO
ADA
Assistant
Adm. for
International
Aviation
Assistant Adm.
for Security &
Hazardous
Materials
API
ASH
Assistant
Adm. for
Human
Resource
Management
AHR
Assistant
Adm. for
Financial
Services
ABA
AEU
ADG
AHA
ABU
APC
AEO
AHD
AFC
AWH
AHS
AHL
AFM
AIN
AHP
AIO
AIS
AEE
AOT
APO
ARD
Air Traffic Organization (ATO)
Vice Presidents
Associate Administrator
for Commercial Space
Transportation
AST
Associate Administrator
for Airports
Associate Administrator
for Aviation Safety
ARP
AVS
Office of Airport
Planning
& Programming
APP
Office of Accident
Investigation
AAI
Safety Services
Office of Airport Safety
& Standards
AAS
Alaskan
Region
AAI
Great Lakes
Region
AGI
Southern
Region
ASO
Central
Region
ACE
Eastern
Region
Office of Aerospace
Medicine
AAM
AJS
Communications
Services
Flight Standards
Service
AFS
Aircraft Certification
Service
AIR
AJC
Operations
Planning
Services
AJP
AFA
New England
Region
ANE
Northwest
Mountain Region
ANM
Southwest
Region
ASW
Western-Pacific
Region
AWP
Office of
Air Traffic Oversight
AOV
Office of
Quality, Integration &
Executive Service AQS
Office of
Rulemaking
ARM
Finance
Services
En Route &
Oceanic
Service
AJE
Terminal
Service
AJT
System
Operations
Services
AJR
Technical
Operations
Services
AJF
AJW
Acquisition
& Business
Services
AJA
Mike Monroney
Aeronautical Center
AMC
FIGURE 1-6
FAA headquarters organizational chart.
FAR Part 121: Operating Requirements: Domestic, Flag, and
Supplemental Air Carrier Operations
FAR Part 139: Certification of Airports
FAR Part 150: Airport Noise Compatibility Planning
FAR Part 151: Federal Aid to Airports
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
FIGURE 1-7
FAA regions.
FAR Part 152: Airport Aid Program
FAR Part 156: State Block Grant Pilot Program
FAR Part 157: Notice of Construction, Alteration, Activation, and
Deactivation of Airports
FAR Part 158: Passenger Facility Charges
FAR Part 161: Notice and Approval of Airport Noise and Access
Restrictions
A complete list of FARs may be found at the Federal Aviation
Administration website http://www.faa.gov.
In addition to federal regulations, the FAA publishes a series of
Advisory Circulars (ACs) to provide guidance into the application of the
regulations. The “150 series” of Advisory Circulars are focused on guiding airport managers and planners. There are more than 100 current and
historical Advisory Circulars within the 150 series. Those of most direct
application to airport planning and design include
AC 150/5020-1: Noise Control and Compatibility Planning for
Airports
AC 150/5060-5: Airport Capacity and Delay
AC 150/5070-6B: Airport Master Plans
AC 150/5070-7: The Airport System Planning Process
AC 150/5300-13: Airport Design
AC 150/5325-4B: Runway Length Requirements for Airport Design
AC 150/5340-1J: Standards for Airport Markings
41
42
Airport Planning
AC 150/5360-12D: Airport Signing and Graphics
AC 150/5360-13: Planning and Design Guidelines for Airport
Terminal Facilities
AC 150/5360-14: Access to Airports by Individuals with
Disabilities
Advisory Circulars are in a constant state of updating. The latest
available ACs may be found at the FAA website at http://www.faa.gov.
Transportation Security Administration
The Transportation Security Administration (TSA) is the agency
within the U.S. Department of Homeland Security responsible for the
security nation’s transportation systems, including civil aviation. The
TSA was formed in 2001 in response to the terrorist attacks of September
11, 2001. In 2003, the TSA moved from the Department of Transportation
to become part of the newly formed Department of Homeland Security.
The TSA is led by an administrator appointed by the President.
With the formation of the TSA, all federal regulations pertaining
to the security of the civil aviation system were moved from Title 14
of the Code of Federal Regulations to Title 49—Transportation, and
have become commonly known as Transportation Security Regulations (TSRs). TSRs of specific importance to airport planners are those
within Subsection C of the TSRs including
49 CFR Part 1500: Applicability, Terms, and Abbreviations
49 CFR Part 1510: Passenger Civil Aviation Security Service Fees
49 CFR Part 1540: Civil Aviation Security: General Rules
49 CFR Part 1542: Airport Security
49 CFR Part 1544: Aircraft Operator Security: Air Carriers and
Commercial Operators
49 CFR Part 1546: Foreign Air Carrier Security
49 CFR Part 1550: Aircraft Security under General Operating and
Flight Rules
Since 2001, the focus of the TSA has been on airport and commercial aviation security. In the future, it is expected that the TSA will
further expand its regulatory role in air cargo and general aviation
security, as well as into other modes of transportation, such as transit,
rail, shipping, and the nation’s highways. More information on the
TSA may be found at its website at http://www.tsa.gov.
Environmental Protection Agency
Established in 1970 as part of the National Environmental Policy Act
(NEPA), the Environmental Protection Agency (EPA) is responsible for
preserving the environment with the goal of protecting human health.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
The EPA has directed many of its efforts to minimizing environmental damage resulting from civil aviation activities, with focus on
aircraft noise levels, emissions, air quality, and water runoff.
Most of the EPA requirements pertaining to civil aviation are
incorporated into the FAA’s Federal Aviation Regulations and policies regarding mandatory environmental impact evaluation of any
proposed airport planning projects. More information on the EPA
may be found at its website at http://www.epa.gov.
National Transportation Safety Board
The National Transportation Safety Board consists of five members
appointed by the President. The NTSB performs the following
functions:
1. Investigates certain aviation, highway, marine, pipeline, and
railroad accidents, and reports publicly on the facts, conditions and circumstances, and the cause or probable cause of
such accidents.
2. Recommends to Congress and federal, state, and local agencies
measures to reduce the incidence of transportation accidents.
3. Initiates and conducts transportation safety studies and
investigations.
4. Establishes procedures for reporting accidents to the board.
5. Assesses accident investigation techniques and issues recommendations for improving accident investigation procedures.
6. Evaluates the adequacy of the procedures and safeguards
used for the transportation of hazardous materials.
7. Reviews, on appeal, the suspension, amendment, modification, revocation, or denial of certain operating certificates,
documents, or licenses issued by the Federal Aviation Administration or the U.S. Coast Guard.
Information about the activities of the NTSB, including all records
of civil aviation accidents and incidents, many of which impact airport planning and design, may be found on the NTSB website at
http://www.ntsb.org.
State Agencies
As mentioned earlier, the states are involved in varying degrees in
the many aspects of aviation including airport financial assistance,
flight safety, enforcement, aviation education, airport licensing, accident investigation, zoning, and environmental control. Because of the
interstate nature of air transportation, the federal government has
43
44
Airport Planning
preempted the legislative and administrative controls since the early
days of aviation. However, for those aviation activities which occur
wholly within the borders of a state, there have been formed regulatory agencies at the state level to oversee that these activities are operated in the best interests of the state.
Many state aviation agencies are participant members in the
National Association of State Aviation Officials (NASAO). The mission of NASAO is to provide representation in Washington, D.C. on
behalf of state aviation departments. Links to individual state aviation departments as well as a host of informational materials may be
found on the NASAO website at http://www.nasao.org.
The International Civil Aviation Organization
Perhaps the most important international agency concerned with airport development is the International Civil Aviation Organization
(ICAO), which is now a specialized agency of the United Nations
with headquarters in Montreal, Canada. One hundred and eightyeight nations were members of ICAO in 2009.
The ICAO concept was formed during a conference of 52 nations
held in Chicago in 1944. This conference was by the invitation of the
United States to consider matters of mutual interest in the field of air
transportation. The objectives of ICAO as stated in its charter are to
develop the principles and techniques of international air transportation so as to
1. Ensure the safe and orderly growth of international civil aviation throughout the world
2. Encourage the arts of aircraft design and operation for peaceful purposes
3. Encourage the development of airways, airports, and air navigation facilities for international aviation
4. Meet the needs of the peoples of the world for safe, regular,
efficient, and economical air transport
5. Prevent economic waste by unreasonable competition
6. Ensure that the rights of contracting states are fully respected
and that every contracting state has a fair opportunity to
operate international airlines
7. Avoid discrimination between contracting states
8. Promote safety of flight in international air navigation
9. Promote generally the development of all aspects of international civil aeronautics
The ICAO has two governing bodies, the Assembly and the
Council. The Council is a permanent body responsible to the Assembly
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
and is composed of representatives from 30 countries. The Council is
the working group for the organization. It carries out the directives
of the Assembly and discharges the duties and obligations specified
in the ICAO charter.
To the airport planner and designer perhaps the most important
document issued by ICAO is “Aerodromes,” Annex 14 to the Convention on International Civil Aviation [1]. Annex 14 contains the international design standards and recommended practices which are
applicable to nearly all airports serving international air commerce.
In addition to Annex 14, ICAO publishes a great deal of technical and
statistical information relative to international air transport [19] and
is available on its website at http://www.icao.org.
Industry and Trade Organizations
There are many groups involved in the technical and promotional
aspects of aviation. The following is a partial list of those groups
which are primarily concerned with the airport aspects of aviation,
most of these professional organizations serve as lobbying groups
promoting the perspectives of the industry groups they represent.
1. Aerospace Industries Association of America (AIA). The national
trade association of companies in the United States engaged
in research, development, and manufacture of aerospace
systems.
2. Aircraft Owners and Pilots Association (AOPA). An association
of owners and pilots of general aviation aircraft. It is headquartered in Frederick, MD, a suburb of Washington, D.C.
3. Air Line Pilots Association, International (ALPA). An association
of airline pilots. It is headquartered in Herndon, VA, a suburb
of Washington, D.C.
4. Airports Council International (ACI). An association of over 400
large airports and airport authorities throughout the world. It
is based in Geneva, Switzerland. The North American region
of this organization (ACI-NA) is headquartered in Washington, D.C. Other regions include Europe, Africa, Asia/Pacific,
and Latin America/Caribbean.
5. Air Transport Association of America (ATA). An association of
scheduled domestic and international airlines in the United
States. The headquarters are in Washington, D.C.
6. American Association of Airport Executives (AAAE). An association of the managers of public and private airports. It is
located in Alexandria, VA, a suburb of Washington, D.C.
7. General Aviation Manufacturers Association (GAMA). An association promoting the interests of general aviation. It is located
in Washington, D.C.
45
46
Airport Planning
8. Helicopter Association International (HAI). An association
which represents the interests of manufacturers and users of
helicopters and promotes the use of helicopters. It is located
in Alexandria, VA, a suburb of Washington, D.C.
9. International Air Transport Association (IATA). An association
of scheduled carriers in international air transportation. This
organization is headquartered in Montreal, Canada.
10. Regional Airline Association (RAA). An association of small
regional and commuter aircraft operators promoting the
needs of this segment of the air transportation industry. It
was formerly called the Commuter Airline Association of
America (CAAA). It is located in Washington, D.C.
References
1. Aerodromes, Annex 14 to the Convention on International Civil Aviation, vol. 1,
Aerodrome Design and Operations, 5th ed., International Civil Aviation
Organization, Montreal, Canada, November 2009.
2. Aerospace Facts and Figures, Aerospace Industries Association of America, Inc.,
Washington, D.C., 1980.
3. Airline Capital Requirements in the 1980s, Economics and Finance Department,
Air Transportation Association of America, Washington, D.C., September
1979.
4. Airline Deregulation, M. A. Brenner, J. O. Leet, and E. Schott, Eno Foundation
for Transportation, Inc, Westport, Conn., 1985.
5. Air Taxi Operators and Commercial Operators, Federal Aviation Regulations, Part 135,
Federal Aviation Administration, Washington, D.C., 1978.
6. Air Transport Facts and Figures, Air Transportation Association of America,
Washington, D.C., annual.
7. Air Transportation, 10th ed., Robert M. Kane, Kendall/Hunt Publishing
Company, Dubuque, Iowa, 1990.
8. Annual Report of the Regional Airline Association, Regional Airline Association,
Washington, D.C., 1991.
9. Aviation System Capacity Plan 1991–1992, Report No. DOT/FAA/ASC-91-1, U.S.
Department of Transportation, Federal Aviation Administration, Washington,
D.C., 1991.
10. Certification and Operations: Domestic, Flag and Supplemental Air Carriers and
Commercial Operators of Large Aircraft, Part 121, Federal Aviation Regulations,
Federal Aviation Administration, Washington, D.C., 1980.
11. Commuter Air, 1981 yearbook edition, Commuter Airline Association of
America, Washington, D.C., April 1981.
12. Commuter Air Carrier Traffic Statistics, 12 months ended June 30, 1980, Civil
Aeronautics Board, Washington, D.C.
13. Current Market Outlook, Boeing Commercial Airplane Group, Seattle, Wash.,
March 1992.
14. Developments in the Deregulated Airline Industry, D. R. Graham and D. P. Kaplan,
Office of Economic Analysis, Civil Aeronautics Board, Washington, D.C., June,
1981.
15. FAA Aviation Forecasts, Fiscal Years 1992–2003, Federal Aviation Administration,
Washington, D.C., February 1992.
16. FAA Statistical Handbook of Civil Aviation, Federal Aviation Administration,
Washington, D.C., 1990.
17. Hearings before Subcommittee on Aviation of the Committee on Commerce, Science,
and Transportation, U.S. Senate, Washington, D.C., August 1980.
T h e N a t u re o f C i v i l Av i a t i o n a n d A i r p o r t s
18. ICAO Journal, International Civil Aviation Organization, Montreal, Quebec,
Canada, monthly.
19. ICAO Publications and Audio Visual Training Aids, Catalogue, International Civil
Aviation Organization, Montreal, Quebec, Canada, 1992.
20. National Airport System Plan, 1978–1987, Federal Aviation Administration,
Department of Transportation, Washington, D.C.
21. National Airspace System Plan, Federal Aviation Administration, Washington,
D.C., 1989.
22. National Plan of Integrated Airport Systems (NPIAS) 1990–1999, Federal Aviation
Administration, U.S. Department of Transportation, Washington, D.C., 1991
23. National Transportation Statistics, annual report, Research and Special Programs
Administration, Department of Transportation, Washington, D.C., July 1990.
24. National Transportation Strategic Planning Study, U.S. Department of
Transportation, Washington, D.C., 1990.
25. Report on Airline Service, Fares, Traffic, Load Factors, and Market Share, a staff study,
fourteenth in a series, Civil Aeronautics Board, Washington, D.C., 1981.
26. Secretary’s Task Force on Competition in the U.S. Domestic Airline Industry, U.S.
Department of Transportation, Washington, D.C., February 1990.
27. Terminal Area Air Traffic Relationships, fiscal year 1980, Federal Aviation
Administration, Washington, D.C.
28. Terminal Area Forecasts, Federal Aviation Administration, Washington, D.C.,
annual.
29. The Changing Airline Industry: A Status Report through 1979, Comptroller General
of the United States, General Accounting Office, Washington, D.C., September
1980.
30. The Federal Turnaround on Aid to Airports 1926–38, The Federal Aviation
Administration, Department of Transportation, Washington, D.C., 1973.
31. Transportation in America, Frank A. Smith, Eno Foundation for Transportation,
Inc., Waldorf, Md., annual.
32. Travel Market Closeup 1989, National Travel Survey Tabulations, US Travel Data
Center, Washington, D.C., 1990.
33. Winds of Change, Domestic Air Transport Since Deregulation, Special Report 230,
Transportation Research Board, National Research Council, Washington, D.C.,
1991.
34. Worldwide Airport Traffic Report, Airports Association Council International,
Inc., Washington, D.C., annual.
35. National Plan of Integrated Airport Systems (NPIAS) 2009–2013, Federal Aviation
Administration, Washington D.C., 2008.
36. Airport Planning and Management, Alex T. Wells and Seth B. Young, McGraw Hill,
2003.
Web References
Bureau of Transportation Statistics: http://www.bts.gov
Federal Aviation Administration: http://www.faa.gov
International Civil Aviation Organization: http://www.icao.org
47
This page intentionally left blank
CHAPTER
2
Aircraft
Characteristics
Related to
Airport Design
O
ne of the great challenges for airport planning and design is
creating facilities that accommodate a very wide variety of
aircraft. Aircraft vary widely in terms of their physical dimensions and performance characteristics, whether they be operated for
commercial air service, cargo, or general aviation activities.
There are a large number of specifications for which aircraft may
be categorized. Depending on the portion of the area of the airport,
certain aircraft specifications become more critical. For example, aircraft weight is important for determining the thickness and strengths
of the runway, taxiway, and apron pavements, and affects the takeoff
and landing runway length requirements at an airport, which in turn
to a large extent influences planning of the entire airport property.
The wingspan and the fuselage length influence the size of parking
aprons, which in turn influences the configuration of the terminal
buildings. Wingspan and turning radii dictate width of runways and
taxiways, the distances between these traffic ways, and affects the
required turning radius on pavement curves. An aircraft’s passenger
capacity has an important bearing on facilities within and adjacent to
the terminal building.
Since the initial success of the Wright Flyer in 1903, fixed-wing
aircraft have gone through more than 100 years of design enhancements, resulting in vastly improved performance, including the ability to fly at greater speeds and higher altitudes over larger ranges
with more revenue generating carrying capacity (known as payload)
at greater operating efficiencies. These improvements are primarily
the results of the implementation of new technologies into aircraft
49
50
Airport Planning
specifications, ranging from materials from which the airframes are
built, to the engines that power the aircraft. Of great challenge to airport planning and design, historically has been to adapt the airport
environment to accommodate changes in aircraft physical and performance specifications. For example:
• The introduction of “cabin-class” aircraft, such as the Douglas DC-3, in the mid-1930s resulted in the need for airports to
construct longer, paved runways from the shorter grass strips
that previously existed.
• The introduction of aircraft equipped with turbofan and turbojet engines in the late 1950s added requirements for longer
and stronger runways, facilities to mitigate jet-blast, and policies to reduce the impact of aircraft noise at and around the
airport.
• The introduction of “jumbo-jet” or “heavy” aircraft, such as
the Boeing-747, in the late 1960s added new requirements for
runway specifications, as well as terminal area design requirements for accommodating large volumes of passengers and
cargo.
• The proliferation of regional jet aircraft, introduced because
of more efficient engine technologies, resulted in the need for
airports to modify many terminal areas that had accommodated larger jets or smaller turbo-prop aircraft.
Most recently, the introduction of the world’s largest passenger
aircraft, the Airbus A-380, as well as the smallest of certified general
aviation jet aircraft, continues to affect design specifications of airport
airfield and terminal areas.
Table 2-1 provides a summary of some of the important aircraft
characteristics of some of the aircraft that make up the world’s commercial airline fleet. Many regional airlines use smaller aircraft with
less than 50 seats, while the world’s major airlines use very large aircraft, with potential configurations for more than 800 seats.
Table 2-2 provides a summary of important aircraft characteristics for common general aviation aircraft. While it should be noted
that aircraft designed primarily for air carrier purposes are also often
used for general aviation activity (e.g., the Boeing 737 is often configured for personal or business use and marketed as the Boeing Business Jet), most general aviation aircraft are smaller than typical commercial airline aircraft. Some of the aircraft listed in Table 2-2 are part
of the fleet of “very light jets” that have emerged into the market
since 2007.
Many of the values provided in Tables 2-1 and 2-2 are only approximate and tend to vary by specific model, as well as by each individual operation. For more precise values appropriate references, such
Turboprop Aircraft
# Engines
Avg. #
Seats
Runway
Required
(ft)*
Aircraft
Wingspan
Length
MSTOW†
(lb)
Beech 1900c
54’06”
57’10”
16,600
2
19
3,300
Shorts 360
74’10”
70’10”
27,100
2
35
4,300
Dornier 328-100
68’10”
68’08”
27,557
2
30
3,300
SAAB 340B
70’04”
64’09”
28,500
2
37
4,200
AT-42-300
80’06”
74’05”
36,815
2
45
3,600
EMB 120
64’11”
65”7”
26,433
2
30
5,200
†
Jet Aircraft Less than 100,000 lb MSTOW (Regional Jets)
#
Engines
Avg. #
Seats
Runway
Required
(ft)*
Aircraft
Manufacturer
Wingspan
Length
MSTOW†
(lb)
ERJ 135
Embraer
65’9”
86’5”
41,887
2
35
5,800
ERJ 140
Embraer
65’9”
93’4”
44,313
2
40
6,100
ERJ 145
Embraer
65’9”
98’0”
46,275
2
50
7,500
CRJ 200
Bombardier
69’7”
87’10”
51,000
2
50
5,800
CRJ 700
Bombardier
76’3”
106’8”
72,750
2
70
5,500
CRJ 900
Bombardier
81’6”
119’4”
80,500
2
90
5,800
51
TABLE 2-1
Characteristics of Commercial Service Aircraft
Jet Aircraft Less than 100,000 lb MSTOW† (Regional Jets)
52
#
Engines
Avg. #
Seats
Runway
Required
(ft)*
Aircraft
Manufacturer
Wingspan
Length
MSTOW†
(lb)
BAe-RJ70
British
Aerospace
86’00”
78’9”
89,999
2
95
4,700
BAe-RJ85
British
Aerospace
86’00”
86’11”
92,999
2
110
5,400
Bae-RJ100
British
Aerospace
86’00”
94’10”
97,499
2
110
6,000
Jet Aircraft between 100,000 and 250,000 lb MSTOW† (Narrow Body Jets)
Wheel
Track
MSTOW†
(lb)
#
Engines
Avg. #
Seats
Runway
Required
(ft)*
Aircraft
Manufacturer
Wingspan
Length
Wheel
Base
A-319
Airbus
Industrie
111’25”
111’02”
41’33”
24’93”
141,095
2
140
5,800
MD-87
McDonnellDouglas
107’10”
130’05”
62’11”
16’08”
149,500
2
135
7,600
MD-90-30
McDonnellDouglas
107’10”
152’07”
77’02”
16’08”
156,000
2
165
6,800
A-320-200
Airbus
Industrie
111’03”
123’03”
41’05”
24’11”
158,730
2
160
5,700
B-737-800
Boeing
112’06”
124’11”
50’09”
18’8”
172,445
2
175
B-727-200
Boeing
108’00”
153’03”
63’03”
18’09”
184,800
3
165
8,600
B-757-200
Boeing
124’10”
155’03”
60’00”
24’00”
220,000
2
210
5,800
Jet Aircraft Greater than 250,000 lb MSTOW† (Wide Body Jets)
A310-300
Airbus
Industrie
144’00”
153’01”
49’11”
31’06”
330,690
2
240
7,500
B-767-300
Boeing
156’01”
180’03”
74’08”
30’06”
345,000
2
275
8,000
A-300-600
Airbus
Industrie
147’01”
175’06”
61’01”
31’06”
363,765
2
310
7,600
L-1011-500
Lockheed
164’04”
164’03”
61’08”
36’00”
510,000
3
290
9,200
B-777-200
Boeing
199’11”
209’01”
84’11”
36’00”
535,000
2
375
8,700
DC-10-40
McDonnellDouglas
165’04”
182’03”
72’05”
35’00”
555,000
3
325
9,500
A-340-200
Airbus
Industrie
197’10”
195’00”
62’11”
16’09”
558,900
4
320
7,600
DC-10-30
McDonnellDouglas
165’04”
182’03”
72’05”
35’00”
572,000
3
320
9,290
MD-11
McDonnellDouglas
170’06”
201’04”
80’09”
35’00”
602,500
3
365
9,800
B-747SP
Boeing
195’08”
184’09”
67’04”
36’01”
630,000
4
315
7,000
B-747-400
Boeing
213’00”
231’10”
84’00”
36’01”
800,000
4
535
8,800
TABLE 2-1
Characteristics of Commercial Service Aircraft (Continued)
53
54
Jet Aircraft between 100,000 and 250,000 lb MSTOW† (Narrow Body Jets)
Wheel
Track
MSTOW†
(lb)
#
Engines
Avg. #
Seats
Runway
Required
(ft)*
Aircraft
Manufacturer
Wingspan
Length
Wheel
Base
B-787-8
Dreamliner
Boeing
197’04”
186’02”
74’09”
32’07”
242,000
2
230
9,600
A-380
Airbus
Industrie
261’08”
239’03”
99’08”
46’11”
1,235,000
4
525
10,000
∗
Runway lengths are takeoff runway length estimates based on sea level elevation, temperature 20°C at maximum takeoff weight. It should be noted
that required runway length varies considerably based on aircraft weight and local atmospheric conditions.
†
MSTOW is maximum structural takeoff weight.
TABLE 2-1
Characteristics of Commercial Service Aircraft (Continued)
Piston and Turbo-Prop Engine Aircraft
Aircraft
Manufacturer
Wingspan
Length
MSTOW (lb)
PA28-Archer
Piper
35’00”
23’09”
DA-40
Diamond
39’06”
26’09”
2,645
1
4
1,198
PA28-Arrow
Piper
35’05”
24’08”
2,750
1
4
1,525
C-182 Skylane
Cessna
35’10”
28’01”
2,950
1
4
1,350
SR20-G2
Cirrus
35’07”
26’00”
3,000
1
4
1,446
SR-22
Cirrus
38’04”
26’00”
3,400
1
4
1,028
PA-32 Saratoga
Piper
36’02”
27’08”
3,600
1
6
1,760
Corvalis 400
Cessna
36’01”
25’02”
3,600
1
4
2,600
DA-42 Twin Star
Diamond
44’06”
28’01”
3,748
2
4
1,130
C-310
Cessna
37’06”
29’07”
5,500
2
6
1,790
BN2B-Islander
Britten-Norman
49’00”
35’08”
6,600
2
9
1,155
C-402c
Cessna
44’01”
36’05”
6,850
2
10
2,195
2,550
# Engines
1
Avg. # Seats
4
Runway Required*
1,660
Cheyenne IIIA
Piper Aircraft
47’08”
43’05”
11,200
2
10
2,400
Super KingAir
Beechcraft
54’06”
43’09”
12,500
2
12
2,600
C-208 Grand
Caravan
Cessna
52’01”
41’07”
8,750
1
14
1,500
TABLE 2-2
Characteristics of General Aviation Aircraft
55
56
Very Light Jet Aircraft
Aircraft
Manufacturer
Wingspan
Length
Mustang
MSTOW (lb)
# Engines
Avg. # Seats
Runway Required*
Cessna
43’2”
40”7”
8,645
2
5
3,100
Eclipse 500
Eclipse
33’6”
33’6”
5,995
2
5
2,400
Hondajet
Honda
39’10”
41’8”
9,200
2
5
3,100
Business Jet Aircraft
∗
Citation CJ1
Cessna
46’11”
42’7”
10,800
2
5
3,300
Citation X
Cessna
56’4”
52’6”
36,400
2
10
3,560
Lear 45 XR
Bombardier
47’9”
57’6”
21,500
2
9
5,040
Lear 60 XR
Bombardier
43’9”
58’6”
23,500
2
9
3,400
Hawker 850 XP
Beechcraft
54’04”
51’02”
28,000
2
8
5,200
G-IV
Gulfstream
77’10”
88’04”
73,200
2
19
5,000
G-550
Gulfstream
93’06”
96’05”
85,100
2
19
5,150
Runway lengths are takeoff runway length estimates based on sea level elevation, temperature 20°C at maximum takeoff weight. It should be noted
that required runway length varies considerably based on aircraft weight and local atmospheric conditions.
TABLE 2-2
Characteristics of General Aviation Aircraft (Continued)
Aircraft Characteristics Related to Airport Design
as an airplane’s characteristics and performance handbook, should
be consulted. In particular, the runway length required to operate a
particular aircraft, whether it be a takeoff or a landing, can vary considerably based on aircraft engine performance and total operating
weight, as well as by the local environmental and atmospheric conditions. Calculation of required runway length is often performed prior
to each operation as part of aircraft flight planning, often using tables,
charts, or formulas provided by the aircraft manufacturer.
While there have certainly been recent breakthroughs in the introduction of very large aircraft such as the Airbus A-380, the overall
trend in aircraft manufactured for civil air transport has focused
design on efficiency, rather than the historical goals of increased size.
More efficient aircraft may be smaller than older generation aircraft,
but their increased efficiencies allow operators to focus on increasing
service frequencies. This increase in operating efficiency has also
shifted the focus of increasing aircraft speeds, at least in the realm of
producing supersonic aircraft (i.e., those that travel at speeds greater
than the speed of sound), to more efficient subsonic aircraft. As such
production and operation of supersonic aircraft, such as the Concorde, was retired in the early part of the twenty-first century.
Dimensional Standards
Figure 2-1 illustrates some of the terms related to aircraft dimensions
that are important to airport planning and design.
The length of an aircraft is defined as the distance from the front
tip of the fuselage, or main body of the aircraft, to the back end of the
tail section, known as the empennage. The length of an aircraft is used
to determine the length of an aircraft’s parking area, hangars. In addition for a commercial service airport, the length of the largest aircraft
to perform at least five departures per day determines the required
amount of aircraft rescue and firefighting equipment on the airfield.
The wingspan of an aircraft is defined as the distance from wingtip
to wingtip of the aircraft’s main wings. The wingspan of an aircraft is
used to determine the width of aircraft parking areas and gate spacing, as well as determining the width and separations of runways
and taxiways on the airfield.
The maximum height of an aircraft is typically defined as the distance from the ground to the top of the aircraft’s tail section. Only in
rare cases is an aircraft’s maximum height found elsewhere on the
aircraft, for example, the Airbus Beluga’s maximum height is noted
as the distance from the ground to the top of the forward fuselage
entry door when it is fully extended upward in the open position.
The wheelbase of an aircraft is defined as the distance between the
center of the aircraft’s main landing gear and the center of its nose gear,
or tail-wheel, in the case of a tail-wheel aircraft. An aircraft’s wheel track
is defined as the distance between the outer wheels of an aircraft’s
57
Airport Planning
Wingspan
Wheel tread or track
Front View
Length
Maximum
height
58
Nose
gear
Main gear
Wheelbase
Side View
FIGURE 2-1
Aircraft dimensions.
main landing gear. The wheelbase and wheel track of an aircraft
determine its minimum turning radius, which in turn plays a large role
in the design of taxiway turnoffs, intersections, and other areas on an
airfield which require an aircraft to turn.
Turning radii are a function of the nose gear steering angle. The
larger the angle, the smaller the radii. From the center of rotation the
distances to the various parts of the aircraft, such as the wingtips,
the nose, or the tail, result in a number of radii. The largest radius is
the most critical from the standpoint of clearance to buildings or
adjacent aircraft. The minimum turning radius corresponds to the
maximum nose gear steering angle specified by the aircraft manufacturer. The maximum angles vary from 60° to 80°, although for design
purposes a steering angle of approximately 50° is often applied.
The turning radius of an aircraft may be expressed using the following formula:
R180° turn = b tan (90 − b) + t/2
where b = wheelbase of an aircraft
t = wheel track of the aircraft
b = maximum steering angle
(2-1)
Pa
th
of
n
Aircraft Characteristics Related to Airport Design
e
os
ar
ge
s
iu
um
m
r
tu
ng
d
ra
ni
i
in
M
Path of
main gear
FIGURE 2-2
Turning radius.
The center of rotation can be easily determined by drawing a line
through the axis of the nose gear at whatever steering angle is desired.
The intersection of this line with a line drawn through the axes of the
two main gears is the center of rotation. Some of the newer large aircraft have the capability of swiveling the main gear when making
sharp turns. The effect of the swivel is to reduce the turning radius
(Fig. 2-2). Minimum turning radii for some typical transport aircraft
are given in Table 2-3.
Landing Gear Configurations
Aircraft currently operating in the world’s civil use airports have
been designed with various configurations of their landing gear. Most
aircraft are designed with one of three basic landing gear configurations; the single-wheel configuration, defined as a main gear of having
a total of two wheels, one on each strut, the dual-wheel configuration,
defined as a main gear of having a total of four wheels, two on each
strut, and the dual-tandem configuration, defined as two sets of wheels
on each strut. These configurations are illustrated in Fig. 2-3.
59
60
Airport Planning
Radius, ft
Aircraft
Max. Steering
Angle, deg
Wingtips
MD-81/83/88
82
65.9
80.7
74.3
MD-90
82
66.5
85.5
74.6
B-737-800
78
69.4
65.4
73.6
B-727-200
78
71
79.5
80
A-320
70
72.2
60
71.9
B-757-200
65
92
84
91
A-310
65
98
75.6
94.9
108.4
Nose
Tail
A-300-600
65
104.9
87.7
B-767-200
65
112
85
98
B-747-200
70
113
110
125
B-747-SP
70
113
93
97
B-767-300
65
116.4
96.1
DC-10-30
68
118.1
105
MD-11
70
121.5
113.8
10.2
B-767-400
65
129.5
108.2
119.6
A-340
78
130.6
109.9
120.4
B-777-300
70
132
125
142
B-787-8
70
132
B-747-400
70
157
TABLE 2-3
117
100.8
111
96
Minimum Turning Radii for Typical Passenger Aircraft
“S” Single wheel
FIGURE 2-3
96.4
108.4
“D” Dual wheel
“2D” Dual tandem
Traditional landing gear configurations (Federal Aviation Administration).
The landing configurations of the largest of commercial service
aircraft have become more complex than the simple configurations
illustrated in Fig. 2-3. For example, the Boeing 747, Boeing 777, and
Airbus A-380 landing gear configurations are illustrated in Fig. 2-4.
Aircraft Characteristics Related to Airport Design
“2D/2D2”
Double dual tandem
Boeing 747
FIGURE 2-4
“3D”
Triple tandem
Boeing 777
“2D/3D2”
Dual tandem plus
triple tandem
Airbus A-380
Complex landing gear configurations (Federal Aviation Administration).
The complexity of landing configurations prompted the FAA to adopt
standard naming conventions for aircraft landing gear configurations
[60]. Examples of this naming convention are represented in quotes in
Figs. 2-3 and 2-4.
The landing gear configuration plays a critical role in distributing
the weight of an aircraft on the ground it sits on, and thus in turn has
a significant impact on the design of airfield pavements. Specifically,
the more wheels on a landing gear, the heavier an aircraft can be and
still be supported on a ramp, taxiway, or runway of a given pavement
strength.
Aircraft Weight
While the concept of aircraft weight may be thought to be a simple
one, the measurement of the weight of a given aircraft is actually relatively complex. An aircraft will in fact be measured with a certain
number of weight measurements, depending on its level of loading
with fuel, payload, and crew, and assigned maximum allowable
weight values for takeoff, landing, and at rest.
These various measurements of aircraft weight are important to
airport planning and design, in particular the facilities such as ramps,
taxiways, and runways that are designed to support the aircraft.
While it is rare that any two aircraft, even those of the same model
and configuration, have the same weight measurements (as there are
almost always variations between aircraft in equipment, seating configurations, galleys, and other objects), most manufactures will assign
typical weights to their aircraft for planning and design purposes.
These weights are as follows.
The “lightest” measure of an aircraft’s weight is known as the operating empty weight (OEW), the basic weight of the aircraft including
crew and all the necessary gear required for flight but not including
61
62
Airport Planning
payload and fuel. The OEW of an aircraft is considered for the design
of aircraft that may occupy maintenance hangars, aircraft storage facilities, or any other areas that are not intended to support the weight of
an aircraft when loaded with fuel or payload.
The zero fuel weight (ZFW) is the OEW of an aircraft plus the
weight of its payload. The ZFW is the weight of the aircraft at which
all additional weight must be fuel, so that when the aircraft is in flight,
the bending moments at the junction of the wing and fuselage do
not become excessive. The payload is a term which refers to the total
revenue-producing load. This includes the weight of passengers and
their baggage, mail, express, and cargo. The maximum structural payload is the maximum load which the aircraft is certified to carry,
whether this load be passengers, cargo, or a combination of both.
Theoretically, the maximum structural payload is a difference between
the zero fuel weight and the operating empty weight. The maximum
payload actually carried is usually less than the maximum structural
payload because of space limitations. This is especially true for passenger aircraft, in which seats and other items consume a considerable amount of space.
The maximum ramp weight is the maximum weight authorized for
ground maneuver including taxi and run-up fuel. As the aircraft taxis
between the apron and the end of the runway, it burns fuel and consequently loses weight.
The maximum gross takeoff weight is the maximum weight authorized at brake release for takeoff. It excludes taxi and run-up fuel and
includes the operating empty weight, trip and reserve fuel, and payload. The difference between the maximum structural takeoff weight
and the maximum ramp weight is very nominal, only a few thousand
pounds for the heaviest aircraft. The maximum gross landing weight
actually varies with certain atmospheric conditions (namely, air density,
which is a function of field elevation and ambient air temperature).
This is due to the fact that at times of low air density (such as at high
elevations and/or high temperatures), an airplane of a given weight
may simply not have the engine power to get takeoff, while at the
same weight it may be able to at a higher air density, found at lower
elevations and/or lower air temperatures.
The maximum structural takeoff weight (MSTOW), is typically
designed as the maximum gross takeoff weight for an aircraft operating at sea level elevation at a temperature of 59°F (15°C). It is also the
maximum weight that the aircraft’s landing gear can support. The
MSTOW is the standard design weight measurement used in airport
planning and design.
The maximum structural landing weight (MLW) is the structural
capability of the aircraft in landing. The main gear is structurally
designed to absorb the forces encountered during landing; the larger
the forces, the heavier must be the gear. Normally the main gears of
transport category aircraft are structurally designed for a landing at a
Aircraft Characteristics Related to Airport Design
weight less than the maximum structural takeoff weight. This is so
because an aircraft loses weight en route by burning fuel. This loss in
weight is considerable if the journey is long, being in excess of 80,000 lb
for large jet transports. It is therefore not economical to design the
main gear of an aircraft to support the maximum structural takeoff
weight during landing, since this situation will rarely occur. If it does
occur, as in the case of aircraft malfunction just after takeoff, the pilot
must jettison or burn off sufficient fuel prior to returning to the airport so as not to exceed the maximum landing weight. For short range
aircraft, the main gear is designed to support, in a landing operation,
a weight nearly equal to the maximum structural takeoff weight. This
is so because the distances between stops are short, and therefore a
large amount of fuel is not consumed between stops.
On landing, the weight of an aircraft is the sum of the operating
weight empty, the payload, and the fuel reserve, assuming that the
aircraft lands at its destination and is not diverted to an alternate airport. This landing weight cannot exceed the maximum structural
landing weight of the aircraft. The takeoff weight is the sum of the
landing weight and the trip fuel. This weight cannot exceed the maximum structural takeoff weight of the aircraft.
Engine Types
Perhaps the most significant contributor to increased aircraft performance has historically come from improvements in aircraft engine
technology, from early twentieth-century piston engines to twentyfirst-century high-performance jet engine technology.
While there are many makes and models of aircraft engines produced by a number of engine manufacturers, aircraft engine types
can generally be placed into three categories, piston engines, turboprops, and turbofan (or jet) engines.
The term piston engine applies to all propeller-driven aircraft powered by high-octane gasoline-fed reciprocating engines. Most small
general aviation aircraft are powered by piston engines. The term turboprop refers to propeller-driven aircraft powered by turbine engines.
The term turbofan or jet has reference to those aircraft which are not
dependent on propellers for thrust, but which obtain the thrust
directly from a turbine engine. Jet engines are typically powered
using a form of diesel fuel, known as Jet-A. While historically jet
engines have been used to power larger general aviation and commercial service aircraft, jet engines recently have been increasingly
produced for smaller “regional jet” commercial service aircraft, and
even smaller “very light jet” general aviation aircraft.
In the early part of the twenty-first century, most of the transport
category aircraft in service are equipped with jet engines, and as such,
much of the planning and design of airports serving commercial service and business general aviation are based around jet engine aircraft.
63
64
Airport Planning
Jet engines can be classified into two general categories, turbojet
and turbofan. A turbojet engine consists of a compressor, a combustion chamber, and a turbine at the rear of the engine. The early jet
airline aircraft, particularly the Boeing 707 and the DC-8, were powered by turbojet engines, but these were discarded in favor of turbofan engines principally because the latter are far more economical.
A turbofan is essentially a turbojet engine to which has been
added large-diameter blades, usually located in front of the compressor. These blades are normally referred to as the fan. A single row of
blades is referred to as single stage, two rows of blades as multistage.
In dealing with turbofan engines reference is made to the bypass
ratio. This is the ratio of the mass airflow through the fan to the mass
airflow through the core of the engine or the turbojet portion. In a
turbofan engines the air flow through the core of the engine, the inner
flow, is hot and very compressed and is burned in it. The air flow
through the fan, the outer flow, is compressed much less and exits
from the engine without burning into an annulus around the inner
core. Fan engines are quieter than turbojet engines and the development of quiet propulsive integrated power plants in modern turbofan has included extensive acoustic lining development both in the
inlet and the fan exhaust [38].
Most fans are installed in front of the main engine. A fan can be
thought of as a small diameter propeller driven by the turbine of the
main engine. Nearly all airline transport aircraft are now powered by
turbofan. Current technological advances in engines are concentrated
toward the development of propfan engines for short and medium
haul aircraft and ultrahigh bypass ratio turbofan engines for long
haul aircraft. These engine technologies reduce fuel consumption by
25 to 35 percent. These engines, which are variously termed unducted
fan (UDF) engines and ultrahigh bypass ratio (UHB) turbofan engines,
have brought on the emergence of very light jet aircraft.
Jet engine performance is made in measured both in terms of
power and efficiency. The power of an aircraft engine is typically
measured in pounds of forward moving force, or “thrust.” Table 2-4
lists a sample of jet engines, and their measurements of thrust installed
on historical and current transport category aircraft.
Aircraft engine power efficiency is measured in terms of the
thrust-to-weight ratio, defined simply as the pounds of thrust provided by the engine, divided by the weight of the engine. Early jet
engines were produced with thrust-to-weight ratios of approximately
3:1. In the early part of the twenty-first century, new light but powerful jet engines with thrust to weight ratios nearing 5:1 have significantly improved the operating efficiency of air transport aircraft and
have made the emergence of the very light jet market feasible.
One important measure of engine performance efficiency is that
of specific fuel consumption, expressed in terms of pounds of fuel per
Engine Family
Manufacturer
Max. Thrust (lb) Aircraft
PW610F
Pratt and Whitney
900 Eclipse 500
PW615F
Pratt and Whitney
1,350 Cessna Mustang
PW617F
Pratt and Whitney
1,700 Embraer Phenom 100
JT8D
Pratt and Whitney
21,000 DC-9, MD-80, SUPER 27
PW6000
Pratt and Whitney
24,000 A318
V2500
Pratt and Whitney
32,000 A-319, A-320, A-321, MD-90
PW2000
Pratt and Whitney
43,000 B-757, C -17, IL-96
JT9D
Pratt and Whitney
56,000 B-747, B-767, A-300, A-310, DC-10
PW4000-94
Pratt and Whitney
62,000 B-747-400, B767-200/300, MD-11, A-300, A-310
PW4000-100
Pratt and Whitney
69,000 A-300-200/300
GP7000
Pratt and Whitney
70,000 A-380
PW4000-112
Pratt and Whitney
98,000 B-777-200/300
RB211-535
Rolls-Royce
43,000 B-757-200/300, Tu-204
Trent 500
Rolls-Royce
56,000 A-340-500/600
RB211-524
Rolls-Royce
61,000 L-1011, B-747-200/400/400/SP/F, B-767-300
Trent 700
Rolls-Royce
71,000 A-330
65
TABLE 2-4
Turbojet Aircraft Engines
66
Engine Family
Manufacturer
Max. Thrust (lb) Aircraft
Trent 900
Rolls-Royce
76,000 A-380
Trent 800
Rolls-Royce
95,000 B-777-200/300
CT7
General Electric
2,100 Bell-214ST, Saab 340a
CF34
General Electric
20,000 CRJ-100-200/700/900, ARJ21, EMBRAER 170,175,190,195
CF6
General Electric
72,000 A-300, A-310, A-330
Genx
General Electric
75,000 8787, B-747-800
GE90
General Electric
115,000 B-777-200/ER/LR/300ER
CFM56-5B
GE/International Aerospace
33,000 A-318, A-319, A-320, A-321
CFM56-3
GE/International Aerospace
24,000 A-737-300/400/500
CFM56-2
GE/International Aerospace
24,000 B-707, KC-135
CFM56-7B
GE/International Aerospace
27,000 B-737-600/700/800/900, BBJ
CFM56-5A
GE/International Aerospace
27,000 A-319, A-320
CFM56-5C
GE/International Aerospace
34,000 A-340-200/300
V2500
International Aero
33,000 A-319, A-320, A-321, ACJ, MD-90
TABLE 2-4
Turbojet Aircraft Engines (Continued)
Aircraft Characteristics Related to Airport Design
Aircraft
A340
B-757
A-330-300
A320
B737-400/500
A-310
B-767-200
B-747-400
B-737-600
A-321-200
BA-146-300
MD-80
∗
Engine
CFM56-5C2
PW2037
CF6-80E1A2
CFM56-5A1
CFM56-3Ca
PW4152
CF6-80A2
PW4056
CFM56-7B20
V2533-A5
LF507
JT8D-219
Bypass Radio
6.4
6.0
5.1
6.0
6.0
4.9
4.7
4.9
5.5
4.6
5.6
1.8
Specific Fuel
Consumption*
0.32
0.33
0.33
0.33
0.33
0.348
0.35
0.359
0.36
0.37
0.406
0.519
Specific Fuel Consumption is the amount of fuel required, in pounds, to create
1 lb of thrust.
TABLE 2-5
Performance Characteristics of Typical Jet Aircraft Engines
hour per pound of thrust. Fuel consumption of jet aircraft engines
tends to be expressed in pounds rather than in gallons. This is because
the volumetric expansion and contraction of fuel with changes in
temperature can be misleading in the amount of fuel which is available. Each gallon of jet fuel weighs about 6.7 lb.
Specific fuel consumption for a particular type of aircraft, defined as
the amount of fuel required (in pounds) to create 1 lb of thrust, is a
function of its weight, altitude, and speed. Some typical values are
given in Table 2-5 merely to illustrate the fuel economy of a turbofan
engine particularly at high bypass ratios (a jet engine’s bypass ratio is
defined as the ratio between the mass flow rate of air drawn in by the
fan but bypassing the engine core to the mass flow rate passing
through the engine core). Significant gains in specific fuel consumption have been made with modern aircraft. Table 2-6 gives the approximate average consumption of fuel for typical aircraft.
Fuel consumption improvements in the last two decades have
been significant. New engines, such as the CFM56, CF6, RB211-524D,
and PW4000, as well as derivatives of current engines, have resulted
in significant fuel economy gains.
An indication of the differences in fuel consumption attained by
the various types of passenger aircraft in the different trip modes is
given in Table 2-5. It should be pointed out, however, that the data are
only indicators of fuel consumption and not productivity. Those aircraft which burn the higher rates of fuel generally are capable of
greater speeds and have greater passenger capacity.
67
68
Airport Planning
Fuel Consumption,
lb/h
Fuel Consumption
per Engine lb/h
Aircraft
Engine
EMB-145
AE3007A
2,253
1,127
A320-200
CFM56-5A3
4,054
2,027
A-319-100
CFM56-5A4
6,966
3,483
B-737-500
FM56-3B1R
7,879
3,940
B-737-200
JT8B-15A
8,829
4,415
B-757-200
RB211-535E4B
11,109
5,555
B-767-300
CF6-802C2B2F
11,893
5,947
A340-300
CFM-56-5C4
16,093
4,023
B-747-200
RB211-524D4
28,638
7,160
TABLE 2-6 Average Fuel Consumption of Typical Jet Aircraft
As observed in Fig. 2-5, the fuel consumption in gallons per
available seat mile decreases with increasing route segment length.
This ratio has become increasingly significant to aircraft operations
as the price of fuel has increased dramatically in the early part of the
twenty-first century. Most significantly for airport planning and
0.07
Fuel consumption, gal
0.06
0.05
0.04
0.03
Maximum
0.02
Minimum
Average
0.01
500
1000
1500
Trip length, mi
2000
2500
FIGURE 2-5 Fuel consumption in gallons per seat-mile as a function of route
distance.
Aircraft Characteristics Related to Airport Design
3.00
$ per gallon
2.50
2.00
1.50
1.00
0.50
19
8
19 6
8
19 7
8
19 8
8
19 9
9
19 0
9
19 1
9
19 2
9
19 3
9
19 4
9
19 5
96
19
9
19 7
9
19 8
9
20 9
0
20 0
0
20 1
0
20 2
03
20
0
20 4
05
20
0
20 6
07
0.00
Month
FIGURE 2-6 Jet fuel prices, 1986 to 2007 (BTS, ATA).
design, aircraft operators are placing increasing effort into minimizing aircraft operating time at airports, including searching for
shorter taxi times between aircraft parking areas and runways, turnaround times at gate areas, and operating in areas where there is
reduced congestion in the local airspace.
Recent increases in fuel costs, combined with the efforts of air carriers to reduce other operating expenses, have resulted in fuel being
the greatest expense to most air carriers. The historical trends in and
the projections for the price of oil and the price of jet fuel for U.S.
airlines are shown in Fig. 2-6. The cost of jet fuel per gallon had
increased from less than $0.50 in 1987 to nearly $3.50 in 2008 before
decreasing to approximately $1.00 per gallon by the end of 2008
(source: BTS, ATA), further motivating the aircraft industry to engineer more efficient engine propulsion and aircraft technologies and
for aircraft operators and airport planners to create environments
that allow for more efficient operations.
Atmospheric Conditions Affecting Aircraft Performance
Just as they vary in dimensional characteristics, the current fleet of
civil use aircraft varies widely in their respective abilities to fly at
certain speeds and altitudes over certain distances, the runway
lengths required to safely perform landing and takeoff operations, as
well as in the amount of noise emissions and energy consumption.
Many of these variations are not only functions of the aircraft themselves but in the varying environments at which they operate.
To fully understand the varying performance characteristics of
aircraft, it is necessary to understand certain elements the environment in which they operate.
69
70
Airport Planning
Air Pressure and Temperature
Since aircraft are designed to operate in the altitudes of the earth’s
atmosphere from sea level to nearly 50,000 ft above sea level, it is
important to understand the characteristics of the atmosphere at
these altitudes and how altitudes, as well as other atmospheric characteristics, affect aircraft performance.
The performance of all aircraft is affected significantly by the atmospheric conditions in which they operate. These conditions are constantly
varying, based simply on the daily heating and cooling of the earth by
the sun, and the associated winds and precipitation that occur.
In general, the performance of aircraft depends primarily on the
density of the air through which it is operating. The greater the density of the air, the more air molecules flow over the wings, creating
more lift, allowing the aircraft to fly. As air density decreases, aircraft
require larger airspeed to maintain lift. For airport design, for example, this translates to longer runway length requirements when air is
less dense. The density of the air is primarily a function of the air
pressure, measured in English units as inches of mercury (inHg) and
in metric units as millibars (mb) or hectopascals.
Air density is affected by air pressure and air temperature. As air
pressure decreases, there are less air molecules per unit volume and thus
air density decreases. As air temperature increases, the velocity and thus
spacing between air molecules increases, thus reducing air density.
While these characteristics of the atmosphere vary from day to day
and from place to place, for practical convenience for comparing the
performance of aircraft, as well as for planning and design of airports,
a standard atmosphere has been defined. A standard atmosphere represents
the average conditions found in the actual atmosphere in a particular
geographic region. Several different standard atmospheres are in use,
but the one most commonly used is the one proposed by ICAO.
In the standard atmosphere it is assumed that from sea level to an
altitude of about 36,000 ft, known as the troposphere, the temperature
decreases linearly. Above 36,000 to about 65,000 ft, known as the stratosphere, the temperature remains constant; and above 65,000 ft, the temperature rises. Many conventional jet aircraft fly as high as 41,000 ft. The
supersonic transports flew at altitudes on the order of 60,000 ft or more.
In the troposphere the standard atmosphere is defined as follows:
1. The temperature at sea level is 59°F or 15°C. This is known as
the standard temperature at sea level.
2. The pressure at sea level is 29.92126 inHg or 1015 mb. This is
known as the standard pressure at sea level.
3. The temperature gradient from sea level to the altitude at
which the temperature becomes −69.7°F is 3.566°F per thousand feet. That is, for every increase in altitude of 1000 ft, the
temperature decreases by approximately 3.5°F or 2°C.
Aircraft Characteristics Related to Airport Design
Both standard pressure and standard temperature decrease with
increasing altitude above sea level. The following relation establishes the
standard pressure in the troposphere up to a temperature of −69.7°F.
P0 T05 . 2561
=
P
T
(2-2)
where P0 = standard pressure at sea level (29.92 inHg)
P = standard pressure at a specified altitude
T0 = standard temperature at sea level (59°F)
T = standard temperature at a specified altitude
In the above formula, the temperature is expressed in “absolute”
or Rankine units. Absolute zero is equal to −459.7°F, 0°F is equal to
459.7°R, and 59°F is equal to 518.7°R.
Using these criteria, the standard temperature at an altitude of
5000 ft is 41.2°F, and the standard pressure is 24.90 inHg. Table 2-7
contains a partial listing of standard temperatures and pressures. It
is common to refer to standard conditions or standard day. A standard
Altitude,
ft
Temperature,
çF
Pressure,
inHg
Speed of Sound,
kn
0
59.0
29.92
661.2
1,000
55.4
28.86
658.9
2,000
51.9
27.82
656.6
3,000
48.3
26.82
654.3
4,000
44.7
25.84
652.0
5,000
41.2
24.90
649.7
6,000
37.6
23.98
647.7
7,000
34.0
23.09
645.1
8,000
30.5
22.23
642.7
9,000
26.9
21.39
640.4
10,000
23.3
20.58
638.0
20,000
−12.2
16.89
626.2
30,000
−47.8
13.76
614.1
40,000
−69.7
8.90
589.2
50,000
−69.7
7.06
576.3
60,000
−69.7
6.41
573.3
TABLE 2-7
Table of Standard Atmospheres
71
72
Airport Planning
condition is one in which the actual temperature and pressure correspond to the standard temperature and pressure at a particular
altitude. When reference is made to the temperature being “above
standard” it means that the temperature is higher than the standard
temperature.
As aircraft takeoff performance data is typically related to the
local barometric pressure and ambient air temperature, which in turn
affects the density of the air, a defined value known as density altitude
is often used to estimate the density of the air at any given time. Density altitude is a function of the effect of barometric pressure on air
density, defined through the measurement known as pressure altitude, and the ambient temperature.
Assuming that at a standard day at sea level, where the elevation
above sea level is effectively 0, the density altitude on a standard day
would also be 0. If the barometric pressure was less than the standard
pressure of 29.92 inHg, the pressure altitude would be greater than 0.
Conversely, if the barometric pressure was greater than standard
pressure, the pressure altitude would be less than 0. This relates to the
fact that, when the atmospheric pressure drops, the air becomes less
dense, requiring a longer run on the ground to obtain the same
amount of lift as on a day when the pressure is high. Thus a reduction
in atmospheric pressure at an airport has the same effect on its air
density as if the airport had been moved to a higher elevation. Pressure
altitude is defined as the altitude corresponding to the pressure of the
standard atmosphere. Thus if the atmospheric pressure is 29.92 inHg,
the pressure altitude is 0. If the pressure drops to 28.86 inHg, the pressure altitude is 1000 ft. This can be obtained from the formula relating
pressure and temperature. If this lower pressure occurred at a sea
level airport, the geographic altitude would be 0, but the pressure
altitude would be 1000 ft. For airport planning purposes, it is satisfactory to assume that the geographic and pressure altitudes are equal
unless the barometric pressures at a particular site are unusually low
a great deal of the time.
Density altitude is defined as pressure altitude adjusted for temperature. Similar to the effect of barometric pressure on aircraft performance, if the temperature of the air was greater than standard
temperature, the density of the air would be lower and the density
altitude would increase, and if the temperature were lower than
standard, the density altitude would decrease. It is because of the
effect of both barometric pressure and ambient air temperature on
aircraft performance that airports located at high elevations, where
air pressure is generally lower than at sea level, and in locations
where the ambient air temperature often rises well above 59°F, are
airports constructed with longer runways, as longer runways are
required for aircraft to reach needed airspeeds to get sufficient lift for
takeoff, than at sea level elevations, or when temperatures are lower.
Aircraft Characteristics Related to Airport Design
Wind Speed and Direction
Since aircraft depend on the velocity of air flowing over their wings
to achieve lift, and fly through streams of moving air, similar to ships
moving along water with currents, the direction and speed of wind,
both near the surface of airports and at altitudes have great effect on
aircraft performance.
As winds primarily affect the speed at which aircraft operate at
an airport, it is important to understand the basic difference between
two ways of measuring speed in an aircraft, groundspeed and airspeed.
The groundspeed is the speed of the aircraft relative to the ground.
True airspeed is the speed of an aircraft relative to the air flowing
over the airfoil, or wing. For example, if an aircraft is flying at a
groundspeed of 500 kn in air where the wind is blowing in the opposite direction, known as a headwind, at a speed of 100 kn, the true airspeed is 600 kn. Likewise, if the wind is blowing in the same direction, a tailwind, and the aircraft maintained a groundspeed of 500 kn,
the true airspeed would be 400 kn.
On the airport surface, the speed and direction of winds directly
affect aircraft runway utilization. For takeoff and landings, for example, aircraft perform best when operating with the wind blowing
directly toward them, that is, with a direct headwind. Headwinds
allow an aircraft to achieve lift at slower groundspeeds, and thus
allow takeoffs and landings with slower groundspeeds and shorter
runway lengths. While wind blowing from behind an aircraft, that is,
a tailwind is preferable for aircraft flying at altitude, as they achieve
greater groundspeeds at a given airspeed, it is not preferable for takeoff or landing, for precisely the same reason. As such, airports tend to
plan and design runways so that aircraft may operate most often with
direct headwinds, and orient their primary runways in the direction
of the prevailing winds.
It is not very often the case that aircraft fly into a direct headwind
or tailwind. Moreover, it is quite common for an aircraft to takeoff or
land from an airport at such a time when the runways are not oriented directly into the existing wind. When this situation occurs, aircraft performance takes into consideration any effect of what are
known as crosswinds.
While operating in direct headwind, tailwind, or calm conditions,
the direction toward which an aircraft is pointing, or heading, is the
same direction as the aircraft is actually traveling, or tracking over the
ground. However, when operating with a crosswind, the aircraft
heading is different than its track. A common analogy to this situation
is the swimmer swimming across a river with a swift current. Even
though such a swimmer may be pointing directly to the opposite
shore of the river, he or she may end up farther downstream than
simply straight across the river, and to end up directly across the river,
the swimmer would have to point, or head, at some angle upstream.
73
74
Airport Planning
Aircraft navigating a route at altitude operate in precisely the
same manner. A heading is calculated, based on the speed and direction of the wind, and the speed of the aircraft itself, that will give the
aircraft the desired track. The angle between the desired track and the
calculated heading is known as the crab angle. The magnitude of this
angle can be obtained from the following relation:
sin x =
Vc
Vh
(2-3)
where Vc is the crosswind in miles per hour or knots and Vh is the true
airspeed in miles per hour or knots.
The crosswind, Vc, is defined as the component of the wind, Vw,
that is at a right angle to the track. The angle x is referred to as the crab
angle. It will be noted that the magnitude of the angle is directly proportional to the speed of the wind and inversely proportional to the
speed of the aircraft.
As an aircraft approaches a runway, its heading (direction in
which the nose is pointing) is of course also dependent on the strength
of the wind traveling across the path of the aircraft (crosswind). The
approach flight path to the runway is an extension of the centerline of
the runway. An aircraft must fly along this track to safely reach the
runway. The relation between track, heading, and crosswind is illustrated in Fig. 2-7. In order not to be blown laterally off the track by the
wind, the aircraft must fly at an angle x from the track. This means
that when the aircraft is moving slowly, as it does when it approaches
a runway, and there is a strong crosswind, the angle x will be large.
The term Vt is the true airspeed along the track and is equal to Vh cos x.
To obtain the groundspeed along the track, the component of the
wind along the track must be subtracted from Vt. In the diagram the
groundspeed along the track is equal to Vt minus the wind along
the track, Vw sin x. For example, assume that an aircraft was approaching a runway at a speed of 135 kn and the crosswind was 25 kn. The
(W
ind
)
Vc
Vh
Vw
x
Runway
Track
Vt
He
ad
ing
FIGURE 2-7
Crosswind correction.
Aircraft Characteristics Related to Airport Design
crab angle x would be 10°10′. This crab angle is reduced to 0 just prior
to touchdown, so that the aircraft is appropriately pointed straight
down the center of the runway.
While aircraft operators are trained to safely operate aircraft in
these crosswind conditions, it is clearly desirable to minimize this
occurrence. Furthermore, the physical ability of an aircraft to properly land in crosswind conditions is limited by the aircraft’s weight,
landing speed, and existing winds. Often times, small aircraft cannot
safely land if crosswinds on a runway are too great. For this reason,
airports accommodating smaller, slower aircraft are often designed
with runways in several directions, to accommodate varying wind
conditions. As opposed to the primary runways that are oriented into
the prevailing winds, crosswind runways are oriented into the direction of winds occurring less frequently.
The FAA categorizes aircraft by the airspeeds at which they make
approaches to land at an airport, known as the Aircraft Approach
Category, and provides requirements to airports that runways be provided that allow for safe operation of the aircraft that use the airport
for at least 95 percent of the annual wind conditions at the airport.
The design process for estimating the number and orientation of primary, as well as crosswind runways based on the approach category
of selected aircraft is detailed in Chap. 6 of this book.
Aircraft Performance Characteristics
Aircraft Speed
Reference is made to aircraft speed in several ways. Aircraft performance data is typically made reference two airspeeds, namely, true airspeed (TAS) and indicated airspeed (IAS). The pilot obtains his speed
from an airspeed indicator. This indicator works by comparing the
dynamic air pressure due to the forward motion of the aircraft with
the static atmospheric pressure. As the forward speed is increased so
does the dynamic pressure. The airspeed indicator works on the principle of the pitot tube. From physics it is known that the dynamic pressure is proportional both to the square of the speed and to the density
of the air. The variation with the square of the speed is taken care of by
the mechanism of the airspeed indicator, but not the variation in density. The indicator is sensitive to the product of the density of the air
and the square of the velocity. At high altitudes the density becomes
smaller and thus the indicated airspeed is less than the true airspeed.
If the true airspeed is required, it can be found with the aid of
tables. As a very rough guide, one can add 2 percent to the indicated
speed for each 1000 ft above sea level to obtain true airspeed.
The indicated airspeed is of more importance to the pilot than is
the true airspeed. The concern is with the generation of lift, specifically
75
76
Airport Planning
the stall speed, the speed at which there is not enough airflow over
the wings to sustain lift, which is dependent on speed and air density.
At high altitudes an aircraft will stall at a higher speed than it does at
sea level. At higher altitudes, however, the airspeed indicator is indicating speeds lower than true speeds; consequently this is on the safe
side and no corrections are necessary. Thus, an aircraft with a stalling
speed of 90 kn will stall at the same indicated airspeed regardless of
altitude. This is why aircraft manufacturers always report stalling
speeds in terms of indicated airspeed rather than true airspeed. With
the introduction of jet transports and high speed military aircraft, the
reference datum for speed is often the speed of sound. The speed of
sound is defined as Mach 1 (after Ernst Mach, Austrian scientist).
Thus Mach 3 means three times the speed of sound. Most of our current jet transports are subsonic (slower than the speed of sound) and
cruise at a speed in the neighborhood of 0.8 to 0.9 Mach. Many military aircraft are supersonic (faster than the speed of sound). Again the
reader is reminded that when the maximum speed of an aircraft is
quoted as 0.9 Mach, this is in terms of true airspeed and not groundspeed. Such an aircraft can conceivably be traveling at a groundspeed
higher than the speed of sound, depending on the magnitude of the
tailwind.
The speed of sound is not a fixed speed; it depends on temperature
and not on atmospheric pressure. As the temperature decreases, so
does the speed of sound. The speed of sound at 32°F (0°C) is 742 mi/h
(1090 ft/s), at −13°F (−25°C) it is 707 mi/h, and at 86°F (30°C) it is
785 mi/h. In fact, the speed of sound varies 2 ft/s for every change in
temperature of 1°C above or below the speed at 0°C. The speed of
sound at the altitudes at which jets normally fly is less than 700 mi/h,
but at altitudes at which small aircraft normally fly (20,000 ft or less) it
is greater than 700 mi/h.
The speed of sound may be computed from the formula
Vsm = 33.4T 0.5
Vsf = 49.04T 0.5
(2-4)
(2-5)
where Vsm = speed of sound in miles per hour at some temperature
Vsf = speed of sound in feet per second at some temperature
T = temperature in degrees Rankine
For convenience in navigation, aircraft distances and speeds are
measured in nautical miles and knots, just like measurement on the
high seas. One nautical mile (6080 ft) is practically equal to 1 min of
arc of the earth’s circumference. One knot is defined as 1 nmi/h. One
nautical mile is approximately 1.15 land miles.
The performances of aircraft are, in part, defined by the various
speeds at which they can safely liftoff, cruise, maneuver, and approach
Aircraft Characteristics Related to Airport Design
to land. These speeds are defined in aircraft performance manuals as
V-speeds. Such V-speeds include:
Vne: Do-Not-Exceed Speed, the fastest an aircraft may cruise in
smooth air to maintain safe structural integrity.
Va: Design Maneuvering Speed, the recommended speed for an
aircraft performing maneuvers (such as turns) or operating in
turbulent air.
Vlo: Liftoff Speed, the recommended speed at which the aircraft
can safely liftoff.
Vr: Rotate Speed, the recommended speed at which the nose wheel
may be lifted off the runway during takeoff.
V1: Decision Speed, the speed at which, during a takeoff run, the
pilot decides to continue with the takeoff, even if there might be
an engine failure from this point before takeoff. If an aircraft develops an engine issue prior to reaching V1, the pilot will abort the
takeoff.
Vso: Stall Speed (landing configuration), the minimum possible
speed for an aircraft in landing configuration (landing gear down,
flaps extended) to maintain lift. If the aircraft’s airspeed goes
below Vso, the airplane loses all lift and is said to stall. This speed
is also typically the speed at which an aircraft will touch down on
a runway during landing.
Vref: Reference Landing Approach Speed, the speed at which an
aircraft travels when on approach to landing. Vref is typically calculated as 1.3 × Vso.
For airport planning and design, many of these speeds contribute to determining required runway lengths for takeoff and landing,
as well as in determining the maximum number of operations (i.e.,
the capacity) that can be performed on runways over a given period
of time.
Payload and Range
The maximum distance that an aircraft can fly, given a certain level of
fuel in the tanks is known as the aircraft’s range. There are a number
of factors that influence the range of an aircraft, among the most
important is payload. Normally as the range is increased the payload
is decreased, a weight trade-off occurring between fuel to fly to the
destination and the payload which can be carried.
The relationship between payload and range is illustrated in
Fig. 2-8. The point A, the range at maximum payload, designates the
farthest distance, Ra, that an aircraft can fly with a maximum structural payload. To fly a distance of Ra and carry a payload of Pa the aircraft has to take off at its maximum structural takeoff weight; however,
its fuel tanks are not completely filled. Point B, the range at maximum
77
Airport Planning
Pa
D
A
E
Payload
78
B
Pb
C
Rd
Ra
Re
Rb
Rc
Range
FIGURE 2-8 Typical relationship between payload and range.
fuel, represents the farthest distance, Rb, an aircraft can fly if its fuel
tanks are completely filled at the start of the journey. The corresponding payload that can be carried is Pb. To travel the distance Rb, the
aircraft must take off at its maximum structural takeoff weight.
Therefore to extend the distance of travel from Ra to Rb the payload
has to be reduced in favor of adding more fuel. Point C represents
the maximum distance an aircraft can fly without any payload.
Sometimes this is referred to as the ferry range and is used, if necessary, for delivery of aircraft. To travel this distance Rc, the maximum
amount of fuel is necessary, but since there is no payload, the takeoff
weight is less than maximum. In some cases the maximum structural
landing weight may dictate how long an aircraft can fly with a maximum structural payload. If this is the case, the line DE represents
the trade-off between payload and range which must occur since the
payload is limited by the maximum structural landing weight.
The shape of the payload versus range curve would then follow the
line DEBC instead of ABC. Payload versus range depends on a
number of factors such as meteorological conditions en route, flight
altitude, speed, fuel, wind, and amount of reserve fuel. For performance comparison of different aircraft in an approximate way the payload range curves are usually shown for standard day, no wind, and
long range cruise.
The actual payload, particularly in passenger aircraft, is normally
less than the maximum structural payload even when the aircraft is
completely full. This is due to the limitation in the use of space when
passengers are carried. For computing payload, passengers and their
baggage are normally considered as 200 lb units.
The aircraft manufacturers publish payload versus range diagrams in aircraft characteristics manuals for each aircraft which may
be used for airport planning purposes. These diagrams are most
Aircraft Characteristics Related to Airport Design
useful in airport planning for determining the most probable weight
characteristics of aircraft flying particular stage lengths between
airports.
The distribution of the load between the main gears and the nose
gear depends on the type of aircraft and the location of the center of
gravity of the aircraft. For any gross weight there is a maximum aft
and forward center of gravity position to which the aircraft can be
loaded for flight in order to maintain stability. Thus the distribution
of weight between the nose and main gears is not a constant. For the
design of pavements it is normally assumed that 5 percent of the weight
is supported on the nose gear and the remainder on the main gears.
Thus if there are two main gears, each gear supports 47.5 percent of
the total weight. For example, if the takeoff weight of an aircraft is
300,000 lb, each main gear is assumed to support 135,000 lb. If the
main gear has four tires, it is assumed that each tire supports an equal
fraction of the weight on the gear, in this example, 33,750 lb. As will
be discussed in Chap. 7, pavement strengths are designed based on
the maximum structural takeoff weights, as well as the landing gear
and loading configurations, of the aircraft of intended use.
Runway Performance
One of the most critical elements of aircraft performance is how such
characteristics, along with local atmospheric conditions, affect the
runway length for an aircraft to safely takeoff and land.
For any given operation, whether it be a takeoff or landing, an
aircraft will require a certain amount of runway. Required runway
length may vary widely for a specific aircraft, as a result of the aircraft’s weight at the time of the operation, as well as the local atmospheric conditions. For the airport planner and designer, such variations have less direct impact on the design length of runways, and
more to aircraft operators who must determine whether the length of
a runway at a given time is safe for a particular operation. Nevertheless, the airport planner and designer should be aware of how an
aircraft’s performance characteristics specifically affect its runway
length requirements.
The factors which have a bearing on and aircraft’s runway length
requirements for a given operations may be grouped into two general
categories:
1. The physical capabilities of the aircraft under given environmental conditions
2. Requirements set by the government to protect for safe
operations
An aircraft’s performance capabilities and hence runway length
requirements are often significantly affected by certain natural environmental conditions at the airport. The more important of these
79
80
Airport Planning
conditions are temperature, surface wind, runway gradient, altitude
of the airport, and condition of the runway surface.
Field Elevation
All other things being equal, the higher the field elevation of the airport, the less dense the atmosphere, requiring longer runway lengths
for the aircraft to get to the appropriate groundspeed to achieve sufficient lift for takeoff. This increase is not linear but varies with the
weight of the aircraft and with the ambient air temperature.
At higher altitudes the rate of increase is higher than at lower
altitudes. For planning purposes, it can be estimated that between
sea level and 5000 ft above sea level, runway lengths required for a
given aircraft increases approximately 7 percent for every 1000 ft of
increase in elevation, and greater under very hot temperatures
those that experience very hot temperatures or are located at higher
altitudes, the rate of increase can be as much as 10 percent. Thus,
while an aircraft may require 5000 ft of runway to takeoff at an airport at sea level, the same aircraft may require 7500 ft or more at an
airport 5000 ft above sea level, especially during periods of high
temperatures.
Surface Wind
Wind speed and direction at an airport also have a significance on
runway length requirements. Simply, the greater the headwind the
shorter the runway length required, and the greater the tailwind the
longer the runway required. Further, the presence of crosswinds will
also increase the amount of runway required for takeoff and landing.
From the perspective of the planner, it is often estimated that for
every 5 kn of headwind, required runway length is reduced by
approximately 3 percent and for every 7 kn of tailwind, runway
length requirements increase by approximately 7 percent. For airport
planning purposes runway lengths are often designed assuming calm
wind conditions.
Runway Gradient
To accommodate natural topographic or other conditions, runways
are often designed with some level of slope or gradient. As such, aircraft operating for takeoff on a runway with an uphill gradient
requires more runway length than a level or downhill gradient, the
specific amount depending on elevation of the airport and temperature. Conversely, landing aircraft require less runway length when
landing on a runway with an uphill gradient, and more length for a
downhill gradient.
Studies that have been made indicate that the relationship
between uniform gradient and increase or decrease in runway length
is nearly linear [55]. For turbine-powered aircraft this amounts to 7 to
10 percent for each 1 percent of uniform gradient. Airport design
Aircraft Characteristics Related to Airport Design
criteria limit the gradient to a maximum of 1½ percent. Information
provided by aircraft manufacturers in flight manuals is based on uniform gradient, yet most runway profiles are not uniform. In the
United States aircraft operators are allowed to substitute an average
uniform gradient, which is a straight line joining the ends of the runway, as long as no intervening point along the actual path profile lies
more than 5 ft above or below the average line. Fortunately most runways meet this requirement. For airport planning purposes only, the
FAA uses an effective gradient. The effective gradient is defined as
the difference in elevation between the highest and lowest points on
the actual runway profile divided by the length of the runway. Studies indicate that within the degree of accuracy required for airport
planning there is not very much difference between the use of the
average uniform gradient and effective gradient.
Condition of Runway Surface
Slush or standing water on the runway has an undesirable effect on
aircraft performance. Slush is equivalent to wet snow. It has a slippery texture which makes braking extremely poor. Being a fluid, it is
displaced by tires rolling through it, causing a significant retarding
force, especially on takeoff. The retarding forces can get so large that
aircraft can no longer accelerate to takeoff speed. In the process slush
is sprayed on the aircraft, which further increases the resisting forces
on the vehicle and can cause damage to some parts. Considerable
experimental work has been conducted by NASA and the FAA on the
effect of standing water and slush. As a result of these tests, jet operations are limited to no more than ½ in of slush or water. Between ¼
and ½ in depth, the takeoff weight of an aircraft must be reduced
substantially to overcome the retarding force of water or slush. It is
therefore important to provide adequate drainage on the surface of
the runway for removal of water and means for rapidly removing
slush. Both water and slush result in a very poor coefficient of braking friction. When tires ride on the surface of the water or slush the
phenomenon is known as hydroplaning. When the tires hydroplane,
the coefficient of friction is on the order of wet ice and steering ability
is completely lost. Hydroplaning is primarily a function of tire inflation pressure and to some extent the condition and type of grooves in
the tires. According to tests made by NASA, the approximate speed
at which hydroplaning develops may be determined by the following
formula:
Vp = 10 p 0.5
(2-6)
where Vp is the speed in miles per hour at which hydroplaning develops and p is the tire inflation pressure in pounds per square inch.
The range of inflation pressures for commercial jet transports varies from 120 to over 200 lb/in2. Therefore the hydroplaning speeds
81
82
Airport Planning
would range from 110 to 140 mi/h or more. The landing speeds are in
the same range. Therefore hydroplaning can be a hazard to jet operations. Hydroplaning can develop when the depth of water or slush is
on the order of 0.2 in or less, the exact depth depending on tire tread
design, condition of the tires, and the texture of the pavement surface. Smooth tread operating on a smooth pavement surface requires
the least depth of fluid for hydroplaning.
To reduce the hazard of hydroplaning and to improve the coefficient of braking friction, runway pavements have been grooved in a
transverse direction. The grooves form reservoirs for the water on the
surface. The FAA is conducting extensive research to establish standards for groove dimensions and shape [54]. In the past the grooves
were normally ¼ in wide and deep and spaced 1 in apart [44].
Declared Distances
Transport category aircraft are licensed and operated under the code
of regulations known as the Federal Aviation Regulations (FAR). This
code is promulgated by the federal government in coordination with
industry. The regulations govern the aircraft gross weights at takeoff
and landing by specifying performance requirements, known as
declared distances which must be met in terms related to the runway
lengths available. The regulations pertaining to turbine aircraft consider three general cases in establishing the length of a runway necessary for safe operations. These three cases are
1. A normal takeoff where all engines are available and sufficient runway is required to accommodate variations in liftoff
techniques and the distinctive performance characteristics of
these aircraft
2. Takeoff involving an engine failure, where sufficient runway
is required to allow aircraft to continue the takeoff despite the
loss of power, or else brake to a stop
3. Landing, where sufficient runway is required to allow for
normal variation in landing technique, overshoots, poor
approaches, and the like
The regulations pertaining to piston-engine aircraft retain in principal the above criteria, but the first criterion is not used. This particular regulation is aimed toward the everyday, normal takeoff maneuver,
since engine failure occurs rather infrequently with turbine-powered
aircraft. The runway length needed at an airport by a particular type
and weight of turbine-powered aircraft is established by one of the
foregoing three cases, whichever yields the longest length.
In the regulations for both piston-engine aircraft and turbinepowered aircraft, the word runway refers to full-strength pavement (FS).
Aircraft Characteristics Related to Airport Design
Thus, in the discussion which follows, the terms runway and fullstrength pavement are synonymous. In any discussion of the effect of
the regulations on the length of the runway, however, it is important
to note that the current regulations for turbine-powered aircraft do
not require a runway for the entire takeoff distance, while the regulations for piston-engine aircraft normally do.
To indicate why there is a difference in the two regulations with
regard to the length of full-strength pavement, it is necessary to examine in more detail the regulations pertaining to turbine-powered
transports.
These three criteria as defined by the current turbine-powered
transport regulations, FAR Part 25 [12] and Part 121 [23], are illustrated
in Fig. 2-9.
Figure 2-9a illustrates the required landing distance. The regulations state that the landing distance (LD) required for an aircraft landing on a given runway must be sufficient to permit the aircraft to
come to a full stop, stop distance (SD), within 60 percent of this distance, assuming that the pilot makes an approach at the proper speed
and crosses the threshold of the runway at a height of 50 ft. The landing distance must be of full-strength pavement. The landing distance
for piston-engine aircraft is defined in exactly the same manner.
Figure 2-9c, illustrates the runway length requirements for a
normal takeoff with all engines fully operating, Fig. 2-9c defines a
takeoff distance (TOD), which, for a specific weight of aircraft, must
be 115 percent of the actual distance the aircraft uses to reach a height
of 35 ft (D35). Not all of this distance has to be of full-strength pavement. What is necessary is that all this distance be free from obstructions to protect against an overshooting takeoff. Consequently the
regulations permit the use of a clearway (CL) for part of this distance.
A clearway is defined as a rectangular area beyond the runway not
less than 500 ft wide and not longer than 1000 ft in length, centrally
located about the extended centerline of the runway, and under the
control of the airport authorities. The clearway is expressed in terms
of a clearway plane, extending from the end of the runway with an
upward slope not exceeding 1.25 percent above which no object nor
any portion of the terrain protrudes, except that threshold lights may
protrude above the plane if their height above the end of the runway
is not greater than 26 in and if they are located to each side of the
runway. Up to one-half the difference between 115 percent of the distance to reach the point of liftoff, liftoff distance (LOD), and the takeoff
distance may be clearway. The remainder of the takeoff distance must
be full-strength pavement and is identified as the takeoff run (TOR).
Figure 2-9b illustrates the engine-failure case, described as the
case where one engine fails at a critical point during an aircraft takeoff
roll, and the pilot makes an immediate judgmental decision whether
or not to continue with a takeoff, or perform an emergency stop.
83
84
115%
of lif
“Tak
t-off
e-off
dista
Ful
dista
l str
nce
nce”
s
eng
Acc
tan
(115
t
c
ele
% dis
h
e
e
r
r
rate
unw
ilu Dist
tanc
a
f
e
anc
a
to V
e to
in
y
Clea
g
n
e
35 fe
e
E
q
Lif
V
rway
ual
to 3
at 1
et)
t-o
Fu 1
s
cann
than
“Ta
5 fe
“Ac
ll s
ff d
k
h
c
e
t
a
e
r
ele
lf this ot be mo
-off
ist
t
e
35
ft
n
r
a
gth
re
run
dista
“Ta anc
”
De te-stop
nce
run
ke e
cel
wa
“La
era dista
-o
y
te t
n
ff d
nd
eq
o s ce”
ing
ua
ist
top
ls “
an
dis
T
Di
c
a
t
“Cl
e”
an
keear
ce
(d
60 sta
off
way
ist
”
run
% nc
”
a
C
e
”
n
of to
lea
ce
Sto
la s
to th rwa
pw
nd to
3
a
Normal take-off case
ay
5 f n h y ca
in p m
ee al
g
(c)
di us
t) f th nnot
“
st t
C
is
an be
dis be m lear
35
ft
ce
wa
tan or
50 ft
y”
ce e
Lift
-of
Stop
point
f di
Landing case
(a)
Engine failure case
(b)
Stopway - At least as wide as
runway: Must support
airplane without damage
in aborted take-off.
FIGURE 2-9
Declared distances, balanced field concept.
Clearway - Minimum 500 ft wide:
No higher than end of
runway, clear of fixed
obstacles, and under
airport control.
Aircraft Characteristics Related to Airport Design
Federal regulations specify that the takeoff distance required during the engine-failure case is the actual distance to reach a height of
35 ft (D35) with no percentage applied as in the all-engine takeoff
case. This recognizes the infrequency of occurrence of engine failure.
The regulations again permit the use of a clearway, in this case up to
one-half the difference between the liftoff distance and the takeoff
distance, the remainder being full-strength pavement. The regulations for piston-engine aircraft normally require full-strength pavement for the entire takeoff distance.
The engine-failure case also requires that sufficient distance must
also be available to stop the airplane rather than continue the takeoff.
The speed at which engine failure is assumed to occur is selected by
the aircraft manufacturer and is referred to as the critical engine-failure
speed or decision speed, V1. If the engine fails at a speed greater than
this speed, the pilot has no choice but to continue the takeoff. If an
engine actually fails at or prior to this selected speed, the pilot brakes
to a stop. This distance required, from beginning of the takeoff roll to
the emergency stop is referred to as the accelerate-stop distance (DAS).
For piston-engine aircraft only full-strength pavement is normally
used for this purpose. The regulations for turbine-powered aircraft,
however, recognize that an aborted takeoff is relatively rare and permit use of lesser strength pavement, known as stopway (SW), for that
part of the accelerate-stop distance beyond the takeoff run. The stopway is defined as an area beyond the runway, not less in width than
the width of the runway, centrally located about the extended centerline of the runway, and designated by the airport authorities for use
in decelerating the aircraft during an aborted takeoff. To be considered as such, the stopway must be capable of supporting the airplane
during an aborted takeoff without inducing structural damage to the
aircraft. Engineered material arresting systems (EMAS) are being
used as for this purpose with increasing frequency.
Based on the above requirements, aircraft operators estimate a
required field length (FL) for each operation. The field length is generally made up of three components, namely, the full-strength pavement (FS), the partial strength pavement or stopway (SW), and the
clearway (CL).
The preceding regulations for turbine-powered aircraft may be
summarized for each of the cases in equation form to find the required
field length.
Normal takeoff case:
FL1 = FS1 + CL1max
(2-7)
where
TOD1 = 1.15(D351)
(2-7a)
CL1max = 0.50[TOD1 − 1.15(LOD1)]
(2-7b)
85
86
Airport Planning
TOR1 = TOD1 − CL1max
FS1 = TOR1
(2-7c)
(2-7d)
Engine-failure takeoff case:
FL2 = FS2 + CL2max
(2-8)
where
TOD2 = D352
(2-8a)
CL2max = 0.50(TOD2 − LOD2)
(2-8b)
TOR2 = TOD2 − CL2max
FS2 = TOR2
(2-8c)
(2-8d)
Engine-failure aborted takeoff:
FL3 = FS + SW
(2-9)
FL3 = DAS
(2-9a)
FL4 = LD
(2-10)
SD
0 . 60
(2-10a)
where
Landing case:
where
LD =
FS4 = LD
(2-10b)
To determine the required field length and the various components of length which are made up of full-strength pavement, stopway, and clearway, the above equations must each be solved for the
critical design aircraft at the airport. This will result in finding each of
the following values:
FL = max [(TOD1), (TOD2), (DAS), (LD)]
(2-11)
FS = max [(TOR1), (TOR2), (LD)]
(2-12)
SW = [(DAS) − max (TOR1, TOR2, LD)]
(2-13)
Aircraft Characteristics Related to Airport Design
where SWmin is zero.
CL = min [(FL − DAS), (CL1max), (CL2max)]
(2-14)
where CLmin is zero and CLmax is 1000 ft.
If operations are to take place on the runway in both directions, as
is the usual case, the field length components must exist in each direction. Example Problem 2-1 illustrates the application of these requirements for a hypothetical aircraft.
Example Problem 2-1 Determine the runway length requirements according to
the specifications of FAR 25 and FAR 121 for a turbine-powered aircraft with the
following performance characteristics:
Normal takeoff:
Liftoff distance = 7000 ft
Distance to height of 35 ft = 8000 ft
Engine failure:
Liftoff distance = 8200 ft
Distance to height of 35 ft = 9100 ft
Engine-failure aborted takeoff:
Accelerate-stop distance = 9500 ft
Normal landing:
Stop distance = 5000 ft
From Eq. (2-4) for a normal takeoff
TOD1 = 1.15 D351 = (1.15)(8000) = 9200 ft
CL1max = 0.50[TOD1 − 1.15(LOD1)] = (0.50)[9200 − 1.15(7000)] = 575 ft
TOR1 = TOD1 − CL1max = 9200 − 575 = 8625 ft
From Eq. (2-5) for an engine-failure takeoff
TOD2 = D352 = 9100 ft
CL2max = 0.50(TOD2 − LOD2) = 0.50(9100 − 8200) = 450 ft
TOR2 = TOD2 − CL2max = 9100 − 450 = 8650 ft
From Eq. (2-6) for an engine-failure aborted takeoff DAS = 9500 ft
From Eq. (2-7) for a normal landing
LD =
5000
SD
=
= 8333 ft
0 . 60 0 . 60
Using the above quantities in Eqs. (2-8) through (2-11), the actual runway component requirements become
FL = max [(TOD1), (TOD2), (DAS), (LD)]
= max [(9200), (9100), (9500), (8333)] = 9500 ft
FS = max [(TOR1), (TOR2), (LD)]
= max [(8625), (8650), (8333)] = 8650 ft
87
88
Airport Planning
SW = [(DAS) − max (TOR1, TOR2, LD)]
= (9500) − max [(8625), (8650), (8333)] = (9500 − 8650) = 850 ft
CL = min [(FL − DAS), CL1max, CL2max]
= min [(9500 − 9500), 575, 450] = 0 ft
The above regulations, as illustrated in Example Problem 2-1, are
applied at all airports, in the form of declared distances for each runway [1, 9]. Declared distances are the distances that are declared
available and suitable for satisfying the takeoff run, takeoff distance,
accelerate-stop distance and landing distance requirements of aircraft. Four declared distances are commonly reported for each runway. They are the takeoff run available (TORA), takeoff distance
available (TODA), accelerate-stop distance available (ASDA), and
landing distance available (LDA).
The takeoff run available (TORA) is the runway length declared
available and suitable for the ground run of an aircraft during takeoff. For Example Problem 2-1, the TORA would be 8650 ft. The takeoff
distance available (TODA) is the takeoff run available plus the length
of any remaining runway and clearway beyond the far end of the
takeoff run available. For Example Problem 2-1, the TODA would be
9500 ft. The accelerate-stop distance available (ASDA) is the amount of
runway plus stopway declared available and suitable for the acceleration and deceleration of an aircraft during an aborted takeoff. For
Example Problem 2-1, the ASDA would also be 9500 ft. The landing
distance available (LDA) is the runway length available and suitable
for landing an aircraft. For Example Problem 2-1, the LDA would be
8650 ft.
It is apparent that both the takeoff distance and accelerate-stop
distance will depend on the speed the aircraft has achieved when an
engine fails.
Since, for piston-engine aircraft, full-strength pavement was normally used for the entire accelerate-stop distance and the takeoff distance, it was the general practice to select V1, so that the distance
required to stop from the point where V1 was reached was equal to
the distance (from the same point) to reach a specified height above
the runway. The runway length established on this basis is referred to
as the balanced field concept or balanced runway and results in the
shortest runway. For turbine-powered aircraft, the selection of V1 on
this basis will not necessarily result in the shortest runway if a clearway or a stopway is provided.
From an airport planning perspective, it is not typical to design a
runway’s full-strength pavement, stopway, and clearway based on a
given aircraft. Rather, for each individual aircraft operation, a V1
speed is selected which best accommodates the runway on which it
will be operating.
Aircraft Characteristics Related to Airport Design
For example, for an aircraft operating on a relatively short runway,
a lower V1 may be selected, which will allow for a shorter acceleratestop distance, but would require at least some clearway to allow for
the aircraft to safely climb out to 35 ft. Conversely, for relatively long
runways that may have obstacles near the runway’s end, or for runways with less full-strength pavement but a stopway at the runway
end, a higher V1 may be selected, to allow for steeper climb-out under
engine-failure conditions, and the ability to accommodate a longer
accelerate-stop distance.
Thus, one can see that the regulations pertaining to turbinepowered aircraft offer a number of alternatives to the aircraft operator. It should be emphasized that the takeoff distance and the takeoff
run for the engine-failure case must be compared with the corresponding distance for the normal all engine takeoff case. The longer
distance always governs. A further discussion of these concepts is
presented by ICAO [1].
Both aircraft operators and airport planners are interested in
clearways, because clearways will, for a fixed available length of runway, allow the operator additional gross takeoff weight with less
expense to airport management than building full-strength pavement
would require.
Wingtip Vortices
Whenever the wings lift an aircraft, vortices form near the ends of
the wings. The vortices are made up of two counter-rotating cylindrical air masses about a wingspan apart, extending aft along the
flight path. The velocity of the wind within these cylinders can be
hazardous to other aircraft encountering them in flight. This is particularly true if a lighter aircraft encounters a vortex generated by a
much heavier aircraft. The tangential velocities in a vortex are
directly proportional to the weight of the aircraft and inversely proportional to the speed. The more intense vortices are therefore generated when the aircraft is flying slowly near an airport [52]. The
winds created by vortices are often referred to as wake turbulence or
wake vortex.
Once vortices are generated they move downward and drift laterally in the direction of the wind. The rate at which vortices settle
toward the ground is dependent to some extent on the weight of an
aircraft, the heavier the vehicle the faster the vortex will settle.
About one wingspan height above the ground the vortices begin to
move laterally away from the aircraft, as shown in Fig. 2-10. The
duration of a vortex is dependent to a great extent on the velocity of
the wind. When there is very little or no wind they can persist for
longer than 2 min. As a result of these tests, the FAA and ICAO
divide aircraft into three classes for the purposes wake-turbulence
separation minima.
89
90
Airport Planning
FIGURE 2-10 An illustration of wake turbulence.
FAA Wake Turbulence
Classifications by Aircraft
Weight (MSTOW)
ICAO Wake Turbulence
Classifications by Aircraft
Weight (MSTOM)
Category
Weight
Category
Weight
Small
≤41,000 lb
Light
≤7,000 kg
Large
41,000–255,000 lb
Medium
7,000–136,000 kg
Heavy
>255,000 lb
Heavy
>136,000 kg
TABLE 2-8
FAA and ICAO Wake Turbulence Classification
For airport planning and design, as well as air traffic safety purposes, aircraft have been categorized into wake-turbulence classifications, based primarily their maximum structural takeoff weights, as
illustrated in Table 2-8. Operating aircraft of varying wake-turbulence
classifications in the same vicinity has significant effects on the safe
and efficient operation of an airfield.
References
1. Aerodrome Design Manual, Part 1: Runways, 2d ed., Document 9157-AN/901,
International Civil Aviation Organization, Montreal, Canada, 1984.
2. Airbus Industrie A300 Airplane Characteristics for Airport Planning, A.AC E00A,
Airbus Industrie, Biagnac, France, October 1987.
3. Airbus Industrie A300-600 Airplane Characteristics for Airport Planning, D.AC
E00A, Airbus Industrie, Biagnac, France, October 1990.
4. Airbus Industrie A310 Airplane Characteristics for Airport Planning, B.AC E00A,
Airbus Industrie, Biagnac, France, December 1991.
5. Airbus Industrie A320 Airplane Characteristics for Airport Planning, Airbus
Industrie, Biagnac, France, February 1988.
6. Airbus Industrie A340 Airplane Characteristics Airport Planning, Preliminary,
Airbus Industrie, Biagnac, France, July 1991.
Aircraft Characteristics Related to Airport Design
7. “Aircraft of the Future,” W. E. Parsons and J. A. Stern, International Air
Transportation Meeting, Paper 800743, Society of Automotive Engineers,
Warrendale, Pa., May 1980.
8. “Aircraft Wake Turbulence Avoidance,” W. A. McGowan, 12th Anglo-American
Aeronautical Conference, National Aeronautics and Space Administration, Paper
72/6, Washington, D.C., July 1971.
9. Airport Design, Advisory Circular, AC150/5300-13 change 13, Federal Aviation
Administration, Washington, D.C., 2008.
10. Air Taxi Operators and Commercial Operators of Small Aircraft, Federal Aviation
Regulations, Part 135, Federal Aviation Administration, Washington, D.C.,
1978.
11. Airworthiness Standards: Normal, Utility, and Acrobatic Category Airplanes, Federal
Aviation Regulations, Part 23, Federal Aviation Administration, Washington,
D.C., 1974.
12. Airworthiness Standards: Transport Category Airplanes, Federal Aviation Regulations,
Part 25, Federal Aviation Administration, Washington, D.C., 1974.
13. Boeing 707 Airplane Characteristics—Airport Planning, Document D6-58322,
Boeing Commercial Airplane Company, Seattle, Wash., December 1968.
14. Boeing 727 Airplane Characteristics—Airport Planning, Document D6-58324-R2,
Boeing Commercial Airplane Company, Seattle, Wash., June 1978.
15. Boeing 737-100/200 Airplane Characteristics-Airport Planning, Document D6-58325
Revision D, Boeing Commercial Airplane Group, Seattle, Wash., September
1988.
16. Boeing 737-300/400/500 Airplane Characteristics—Airport Planning, Document
D6-58325-2 Revision A, Boeing Commercial Airplane Group, Seattle, Wash.,
July 1990.
17. Boeing 747 Airplane Characteristics—Airport Planning, Document D6-58326, Rev. E,
Boeing Commercial Airplane Group, Seattle, Wash., May 1984.
18. Boeing 747-400 Airplane Characteristics—Airport Planning, Document D6-58326-1,
Rev. B, Boeing Commercial Airplane Group, Seattle, Wash., March 1990.
19. Boeing 757 Airplane Characteristics—Airport Planning, Document D6-58327 Rev D,
Boeing Commercial Airplane Group, Seattle, Wash., September 1989.
20. Boeing 767 Airplane Characteristics—Airport Planning, Document D6-58328 Rev F,
Boeing Commercial Airplane Group, Seattle, Wash., February 1989.
21. Boeing 777 Airplane Characteristics—Airport Planning, Preliminary Information,
Document D6-58329, Boeing Commercial Airplane Group, Seattle, Wash.,
February 1992.
22. British Aerospace 146 Airplane Characteristics for Airport Planning, APM 146.1,
British Aerospace Limited, Hatfield, Hertfordshire, England, June 1984.
23. Certification and Operations—Domestic, Flag, and Supplemental Air Carriers and
Commercial Operators of Large Aircraft, Federal Aviation Regulations, Part 121,
Federal Aviation Administration, Washington, D.C. 1974.
24. Certification and Operations of Scheduled Air Carriers with Helicopters, Federal
Aviation Regulations, Part 127, Federal Aviation Administration, Washington,
D.C., 1974.
25. Commercial Air Transportation in the Next Three Decades, H. W. Withington,
Boeing Commercial Airplane Company, Seattle, Wash., 1980.
26. Commercial Air Transportation 1980’s and Beyond, H. W. Withington, Boeing
Commercial Airplane Company, Seattle, Wash., November 1980.
27. “CTOL Concepts and Technology Development,” D. William Conner,
Astronautics and Aeronautics, American Institute of Aeronautics and Astronautics,
July-August 1978.
28. CTOL Transport Aircraft Characteristics, Trends, and Growth Projections, Aerospace
Industries Association of America, Inc., Washington, D.C., 1979.
29. Current Market Outlook, Boeing Commercial Airplane Group, Seattle, Wash.,
March 1992.
30. DC-8 Airplane Characteristics, Airport Planning, Report DAC-67492, Douglas
Aircraft Company, McDonnell-Douglas Corporation, Long Beach, Calif., March
1969.
91
92
Airport Planning
31. DC-9 Airplane Characteristics, Airport Planning, Report DAC-67264, Douglas
Aircraft Company, McDonnell-Douglas Corporation, Long Beach, Calif.,
September 1978.
32. DC-10 Airplane Characteristics, Airport Planning, Report DAC-67803A, Douglas
Aircraft Company, McDonnell-Douglas Corporation, Long Beach, Calif.,
January 1991.
33. Dimensions of Airline Growth, Boeing Commercial Airplane Company, Seattle,
Wash., March 1980.
34. Energy and Transportation Systems, Final Report, California Department of
Transportation, Sacramento, Calif., December 1981.
35. Environmental Protection, Annex 16 to the Convention on International Civil
Aviation, vol. 1: Aircraft Noise, 2d ed., International Civil Aviation Organization,
Montreal, Canada, 1988.
36. High Speed Civil Transport, Program Review, Boeing Commercial Airplane
Group, Seattle, Wash., 1990.
37. Jane’s All the World’s Aircraft, Franklin Watts, Inc., New York, annual.
38. Jet Aviation Development: One Company’s Perspective, John E. Steiner, Boeing
Commercial Airplane Group, Seattle, Wash, 1989.
39. “Jet Transport Characteristics Related to Airports,” R. Horonjeff and G. Ahlborn,
Journal of the Aerospace Transport Division, vol. 91 AT1, American Society of Civil
Engineers, New York, April 1965.
40. L1011 Airplane Characteristics, Airport Planning Document CER-12013, Lockheed
California Company, Burbank, Calif., December 1972.
41. MD-11 Airplane Characteristics for Airport Planning, Report MDC-K0388,
McDonnell-Douglas Corporation, Long Beach, Calif., October 1990.
42. MD-80 Series Airplane Characteristics for Airport Planning, Report MDC-J2904,
McDonnell-Douglas Corporation, Long Beach, Calif., February 1992.
43. MD-90-30 Aircraft Airport Compatibility Brochure, Report MDC-91K0393,
McDonnell-Douglas Corporation, Long Beach, Calif., February 1992.
44. Measurement, Construction and Maintenance of Skid Resistant Airport Pavement
Surfaces, Advisory Circular, AC 150/5320-12A, Federal Aviation Administration,
Washington, D.C., July 1986.
45. Noise Standards: Aircraft Type and Airworthiness Certification, Federal Aviation
Regulations, Part 36, Federal Aviation Administration, Washington, D.C., 1974.
46. Outlook for Commercial Aircraft 1980-1994, Douglas Aircraft Company,
McDonnell-Douglas Corporation, Long Beach, Calif., June 1980.
47. Pavement Grooving and Traction Studies, NASA SP-5073, Proceedings
of Conference at Langley Research Center, National Aeronautics and Space
Administration, Langley Field, Va., November 1968.
48. “Pneumatic Tire Hydroplaning and Some Effects on Vehicle Performance,”
W. B. Horne and U. T. Joyner, Proceedings of the Society of Automotive Engineers,
Paper 97UC, New York, 1965.
49. “Runway Grooving for Increasing Traction—the Current Program and an
Assessment of Available Results,” W. B. Horne and G. W. Brooks, 20th Annual
International Air Safety Seminar, Williamsburg, Va., December 1967.
50. Runway Length Requirements for Airport Design, Advisory Circular AC 150/5325-4B,
Federal Aviation Administration, Washington, D.C., January 2005.
51. Short-Haul Transport Aircraft Future Trends, Aerospace Industries Association of
America, Inc., Washington, D.C., January 1978.
52. “Simulated Vortex Encounters by a Twin-Engine Commercial Transport Aircraft
during Final Approach,” E. C. Hastings, Jr. and G. L. Keyser, Jr., International
Air Transportation Meeting, Paper 800775, Society of Automotive Engineers,
Warrendale, Pa., May 1980.
53. “Technology Requirements and Readiness for Very Large Vehicles,” D. William
Conner, AIAA Very Large Vehicle Conference, American Institute of Aeronautics
and Astronautics, Arlington, Va., April 1979.
54. The Braking Performance of an Aircraft Tire on Grooved Portland Cement Concrete
Surfaces, S. K. Agrawal and H. Diautolo, Federal Aviation Administration
Technical Center, Report FAA-RD-80-78, Federal Aviation Administration,
Atlantic City, N.J., January 1981.
Aircraft Characteristics Related to Airport Design
55. The Effect of Variable Runway Slopes on Takeoff Runway Length for Transport
Aeroplanes, ICAO Circular 91-AN/75, International Civil Aviation Organization,
Montreal, Canada, 1970.
56. “Trailing Vortex Hazard,” W. A. McGowan, Proceedings of the Society of
Automotive Engineers, Paper 680220, New York, April 1968.
57. Water, Slush, and Snow on the Runway, Advisory Circular, AC 91-6A, Federal
Aviation Administration, Washington, D.C., May 1978.
58. Aeronautical Information Manual, Federal Aviation Administration, Washington,
D.C., 2008.
59. Aircraft Wake Turbulence, Advisory Circular AC 190-23F, Federal Aviation
Administration, Washington, D.C., 2002.
60. Standard Naming Convention for Aircraft Landing Gear Configurations, US DOT
FAA Order 5300.7, October 6, 2005.
93
This page intentionally left blank
CHAPTER
3
Air Traffic
Management
Introduction
In order that the airport planner and designer may be aware of the
importance of the rules and technologies that define the aviation
operations within the airspace, a very brief summary of what constitutes air traffic control, increasingly being known as air traffic management, how it is managed and operated, and the principal aids to
air navigation, is presented in this chapter.
An appreciation of air traffic management and its current and future
operating and technological characteristics will focus attention on the fact
that any extensive reorientation of runways on existing airports or the construction of entirely new airports requires consultation with the organizations in charge of operating surrounding airspace and very often an
airspace study. This is particularly true in large metropolitan areas where
several airports are present and the existing airspace must be shared by
several airports. In addition, the design of local airspace procedures
include procedures for the departure and arrival of aircraft to airport runways requires a fundamental knowledge in current and future air traffic
control technologies and policies. Conflicts in air traffic procedures can
seriously affect the efficiency of any single airport or a system of airports
in a region. The planning of airports must include provisions for facilities
located at airports that support the air traffic management system.
As enhanced air traffic management technologies and strategic
plans continue to be implemented, consideration of local air traffic
procedures has become increasingly relevant and important for even
the smallest of airports.
As of 2008, the air traffic management system was just beginning a
complete system transformation. As such it is imperative of the airport
planner to have an understanding of both the fundamentals of air traffic management and the constant enhancements to the system. This
chapter is intended to only briefly introduce the system to the airport
planner.
95
96
Airport Planning
A Brief History of Air Traffic Management
The first attempt to set up rules for air traffic control was made by the
International Commission for Air Navigation (ICAN), which was
under the direction of the League of Nations. The procedures which
the commission promulgated in July of 1922 were adopted by 14
countries. Although the United States was not a member of the
League of Nations, and therefore did not officially adopt the rules,
many of the procedures established by ICAN were used in the promulgation of air traffic procedures in the United States as well as in
most regions of the world.
Construction and operation of the airways system in the United
States prior to 1926 were controlled by the military and by the Post
Office Department. The formal entry of the federal government into
the regulation of air traffic came with the passage of the Air Commerce
Act of 1926 (Public Law 64-254). This act directed the Bureau of Air
Commerce to establish, maintain, and operate lighted civil airways.
At the present time the Federal Aviation Administration maintains
and operates the airways system of the United States.
The establishment of the International Civil Aviation Organization (ICAO) in 1944 helped to standardize recommended air
traffic control procedures internationally. Today, air traffic control in each country is operated either by its federal government
or by private corporations under governmental supervision and
regulations. Examples of international air traffic control organizations include the Federal Aviation Administration in the United
States, National Air Traffic Services Ltd. (NATS) serving the
United Kingdom, NAV Canada in Canada, and Air Services Australia serving the Australian continent. In addition, Eurocontrol,
an intergovernmental organization comprising 38 member states
within the European Union, coordinates, standardizes, and
assists in managing air traffic in the airspace over the European
continent.
The primary mission of the Federal Aviation Administration, as
well as its international counterparts, is to provide for safe and efficient movement of aircraft throughout the airspace system. The primary function of the air traffic management system is to prevent collisions between aircraft. As such, the FAA office of air traffic
management is made up of and responsible for a series of hierarchical control facilities, ground and satellite based navigational aides
and aircraft routing procedures, as well as a defined system of air
routes and airspace classifications. While much of the current air traffic system is in many ways based on the original development of air
traffic control in the early twentieth century, it should be noted that
air traffic control policies are constantly changing as the most modern technologies are implemented to better manage increasing air
traffic volumes.
A i r Tr a f f i c M a n a g e m e n t
The Organizational Hierarchy of Air Traffic Management
in the United States
In general, aircraft operate in what is known as the National Airspace
System (NAS). The NAS is defined by a series of air routes, airspace
classifications, and navigational aids. Aircraft operate within the NAS
under varying levels of air traffic control, based primarily on the
weather conditions and the type and amount of flight activity within
the area. In areas with very low volumes of flight activity during
excellent visibility conditions, aircraft may operate in the complete
absence of air traffic control, whereas in the busiest airspace or when
visibility is limited, aircraft may be under full “positive” control, only
being able to change speed, course, or altitude by direct orders from
an air traffic controller.
The NAS is operated and managed by a hierarchical organization
of air traffic control facilities. The specific purpose of the air traffic
control service is to prevent collisions between aircraft and on the
maneuvering area between aircraft and obstructions, to expedite and
maintain an orderly flow of air traffic [3].
The Air Traffic Control System Command Center
In the United States, air traffic control is managed on a macro level at
the air traffic control system command center (ATCSCC) in Herndon,
Virginia. In 2007, ATCSCC monitored an average of 25,000 flights per
day, with an average of 6000 flights airborne during peak periods. In
addition, ATCSCC manages flights planned 6 to 12 h in the future,
with the purpose of planning for limiting congestion within the
nation’s airspace. In doing so, ATCSCC has the authority to implement ground delay programs by dictating certain aircraft to remain at
their airports of departure to prevent further congestion in points of
the airspace or at airports suffering from delays due to weather or
heavy traffic volumes.
Air Route Traffic Control Centers
Air route traffic control centers (ARTCCs) have the responsibility of
controlling the movement of en route aircraft along the airways and jet
routes, and in other parts of the airspace. Each of the 21 air traffic
control centers within the United States has control of a defined geographical area which may be greater than 100,000 mi2 in size. At the
boundary point, which marks the limits of the control area of the
center, control of aircraft may be transferred to an adjacent center or an
approach control facility, or radar service may be terminated and VFR
aircraft are free to contact the next center. Air traffic control centers are
normally not located at airports. Air traffic control centers can also
provide approach control service to nontowered airports and to
nonterminal radar approach control airports.
97
98
Airport Planning
Each ARTCC geographical area is divided into sectors. The configuration of each sector is based on equalizing the workload of the
controllers. Control of aircraft is passed from one sector to another.
The geographical area is sectored not only in the horizontal but also
in the vertical plane. Thus there can be a high-altitude sector above
one or more low-altitude sectors. Each sector is manned by one or
more controllers, depending on the volume and complexity of traffic.
The average number of aircraft that each sector can handle depends
on the number of people assigned to the sector, the complexity of traffic, and the degree of automation provided.
Each sector is normally provided with one or more air route surveillance radar (ARSR) units which cover the entire sector and allow
for monitoring of separation between aircraft in the sector. In addition, each sector has information on the identification of the aircraft,
destination, flight plan route, estimated speed, and flight altitude,
which is posted on pieces of paper called flight progress strips, and
are superimposed on the radarscope adjacent to the blips which identify the position and identity of aircraft. The strips are continuously
updated as the need arises.
At present, communication between the pilot and controller is by
voice. Therefore each ARTCC is assigned a number of VHF and UHF
radio communication frequencies. The controller in turn assigns a
specific frequency to the pilot. However, modernization of air traffic
control is planned to include further proliferation of digital communications, known as controller pilot data link communications
(CPDLC) between controllers and pilots.
Terminal Approach Control Facilities
The terminal approach control facility (TRACON) monitors the air traffic in the airspace surrounding airports with moderate to high density
traffic. It has jurisdiction in the control and separation of air traffic from
the boundary area of the air traffic control tower at an airport to a distance of up to 50 mi from the airport and to an altitude ranging up to
17,000 ft. This is commonly referred to as the terminal area. Where there
are several airports in an urban area, one facility may control traffic to all
of these airports. In essence the facility receives aircraft from the ARTCC
and guides them to one of several airports. In providing this guidance, it
performs the important function of metering and sequencing aircraft to
provide uniform and orderly flow to the airports.
The organizational structure of an approach control facility is very
similar to the ARTCC. Like the ARTCC, the geographic area of the facility is divided into sectors to equalize the workload of the controllers. The
approach control facility transfers control of an arriving aircraft to the
airport control tower when it is lined up with the runway about 5 mi
from the airport. Likewise, control of departing aircraft is transferred to
the approach control facility by the airport control tower.
A i r Tr a f f i c M a n a g e m e n t
Airport Traffic Control Tower
The airport traffic control tower (ATCT) is the facility which supervises, directs, and monitors the arrival and departure traffic at the
airport and in the immediate airspace within 5 mi from the airport.
The tower is responsible for issuing clearances to all departing aircraft, providing pilots with information on wind, temperature, barometric pressure, and operating conditions at the airport, and for the
control of all aircraft on the ground except in the maneuvering area
immediately adjacent to the aircraft parking positions called the ramp
area. In the United States in 2007, there were more than 550 air traffic
control towers. While most towers are operated by the FAA, as of
January 2007, 233 were operated by the private sector under the
FAA’s contract tower program. The number of operating contract
towers, as they are known, has increased tremendously since the
inception of the program in 1982. Figure 3-1 provides an illustration
of the new ATCT, overshadowing the previously active ATCT, at the
Hartsfield-Jackson Atlanta International Airport, Atlanta, Georgia.
FIGURE 3-1 The new ATCT dwarfing the old tower at Hartsfield-Jackson
Atlanta International Airport (ATCmonitor.com).
99
100
Airport Planning
Flight Service Stations
While not providing specific control, flight service stations (FSS) are the
element of the air traffic management system that provides information
and other noncontrol communications to aircraft operating in the system. Their principal functions are to accept and close flight plans, brief
pilots about their routes of flight, and to provide important information,
in the form of notices to airmen (NOTAMs) before flight and in flight,
on such items as severe weather, the status of navigational aids, airport
runway closures, and changes in published approach and departure
procedures. A secondary function is to relay traffic control messages
between aircraft and the appropriate control facility on the ground.
Flight service has gone through a number of changes since the
early 1990s. In the 1990s the FAA consolidated more than 180 flight
service stations into approximately 60 automated flight service stations (AFSS) which allow many functions, particularly with respect to
disseminating weather and other NOTAMs and the filing of flight
plans to be performed electronically by voicemail or computer.
In 2005, the FAA awarded a contract to operate the AFSS system
to the Lockheed Martin Corporation, representing another step in the
privatization of major components of the nation’s air traffic control
system. While the privatization of the AFSS system has caused some
controversy within the aviation industry, there has been relatively
little impact of this or any other FAA privatization efforts on airport
planning and design.
Air Traffic Management Rules
Air traffic rules are traditionally applied based on prevailing meteorological conditions. Visual meteorological conditions (VMC) are
applied when there is sufficient visibility for pilots of aircraft to be
able to navigate by referencing locations on the ground, as well as to
be able to see and avoid other aircraft in the area. Around airports,
VMC is defined as at least 3 statute miles visibility and cloud “ceilings” (defined as at least 5/8 of the sky covered by clouds) of at least
1000 ft above the ground (AGL). Conversely, instrument meteorological conditions (IMC) exist when visibilities are less than 3 statute
miles and cloud ceilings are less than 1000 ft above the ground.
At its most basic level, aircraft operating in VMC tend to fly under
visual flight rules (VFR). VFR flight rules depend on aircraft operators to visually maintain adequate separation from terrain, clouds,
and other aircraft. Under VFR, aircraft navigation is based on visual
reference to locations on the ground, including visual identification
and approaches to airports.
While flying under VFR conditions, pilots may request from air
traffic control to be under “flight following.” Under flight following,
air traffic control operators provide assistance to pilots by supervising
A i r Tr a f f i c M a n a g e m e n t
course and altitude changes, as well as actively notifying pilots of
nearby aircraft. Pilots flying under VFR conditions are required to fly
under flight following in the busiest of airspace.
Aircraft flying in IMC or at altitudes over 18,000 ft above sea level
(AMSL) fly under instrument flight rules (IFR). Aircraft flying under
IFR navigate using ground-based and satellite-based navigation aides
and are fully controlled along planned routes by air traffic control personnel. Often times, flights operating under IFR will fly defined departure and approach procedures to and from airports which depend on
flying precise courses and altitudes to and from waypoints as defined
by ground- and satellite-based navigation systems. These published
instrument procedures provide for aircraft to safely and efficiently
depart from and arrive to airport runways while avoiding collisions
with terrain and other aircraft during poor visibility conditions. In many
ways, IFR rules, routes, and departure and approach procedures have
significant influence on the planning, design, and operation of airports.
Airspace Classifications and Airways
In the United States, domestic airspace is defined into six classes, plus
areas with special operating restrictions, and a designated series
routes between airports and waypoints. Aircraft are subject to different levels of air traffic control depending on which airspace classification they are currently operating in, the type of defined route they are
on, and whether they are flying under VFR or IFR flight rules.
Classes of airspace in the United States are identified alphabetically, as Class A, B, C, D, E, or G airspace, as illustrated in Fig. 3-2.
Class A airspace, also known as positive control airspace, is the
airspace between 18,000 ft above mean sea level (AMSL) (known as FL
180) and 60,000 ft (FL 600) AMSL over the 48 contiguous United States
and Alaska, extending out to 12 nm off the coast of the United States.
FL 600
18,000 MSL
CLASS A
14,500 MSL
CLASS E
CLASS B
CLASS C
CLASS D
Nontowered
700 AGL
Airport
CLASS G
AGL-above ground level FL-flight level
FIGURE 3-2
1200 AGL
CLASS G
CLASS G
MSL-mean sea level
Illustration of airspace classes.
Effective September 16, 1993
101
102
Airport Planning
Since aircraft flying in Class A airspace are generally fast moving commercial airline or general aviation aircraft, all aircraft operating in
Class A airspace operate under IFR.
Class B airspace are defined areas within a 30 nm radius around
the busiest airports, including areas of multiple large airports, in the
United States. Class B airspace surrounds 36 of the busiest commercial service airports in the United States. Class B airspace is typically
shaped in the form of what is known in the industry as an “inverted
wedding cake.” Nearest the busiest airports within the radius of Class B
airspace, Class B airspace extends from the surface of the busiest airports in the area to generally 10,000 ft MSL. Farther away from the
airport, Class B may begin at some altitude above the surface and
extend to 10,000 ft MSL. The purpose of Class B airspace is to provide
an area of positive air traffic control to coordinate the many highspeed aircraft transitioning from high altitudes to landing at the busiest airports, and vice versa, with local lower altitude traffic within
the area, while providing airspace at lower altitudes further away
from the airport to be used with lower levels of control for smaller
and slower general aviation aircraft in the region. Aircraft operating
within Class B airspace are under positive air traffic control, and as
such must either be flying under IFR rules or, with permission from
air traffic control, under VFR rules with flight following. An example
depiction of Class B airspace is illustrated in Fig. 3-3. This illustration
is a portion of an airspace sectional chart, provided by the U.S.
Department of Defense and the Federal Aviation Administration as
one standard for identifying classes of airspace, airports, navigational
aids, and air routes in the NAS.
United States Airspace Class B Areas, centered around the following civil airports:
• PHX
Phoenix Sky Harbor International
• LAX
Los Angeles International
• SAN
San Diego International Lindbergh Field
• SFO
San Francisco International
• DEN
Denver International
• MIA
Miami International
• MCO
Orlando International
• TPA
Tampa International
• HNL
Honolulu International
• ORD
Chicago O’Hare International
• CVG
Cincinnati/Northern Kentucky International
• MSY
Louis Armstrong New Orleans International
• BWI
Baltimore/Washington International
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-3
Class B airspace around Tampa International Airport, Tampa, Florida.
• BOS
General E. L. Logan International (Boston)
• DTW
Detroit Metropolitan Wayne County
• MSP
Minneapolis-St. Paul International
• MCI
Kansas City International
• STL
Lambert-St. Louis International
• LAS
Las Vegas McCarran International
• EWR
Newark Liberty International
• JFK
John F. Kennedy International
• LGA
New York LaGuardia
• CLT
Charlotte/Douglas International
• CLE
Cleveland-Hopkins International
103
104
Airport Planning
• CVG
Cincinnati/Northern Kentucky International
Airport
• PHL
Philadelphia International
• PIT
Pittsburgh International
• MEM
Memphis International
• DAL
Dallas Love Field
• DFW
Dallas-Fort Worth International
• HOU
Houston William P. Hobby
• IAH
George Bush Intercontinental (Houston)
• SLC
Salt Lake City International
• DCA
Ronald Reagan Washington National
• IAD
Washington Dulles International
• SEA
Seattle-Tacoma International
Class C airspace is found around airports without as much operating volume as those around Class B airspace, but is busy enough to
warrant some active level of air traffic control within 10 mi of the airport. VFR traffic operating within Class C airspace must adhere to strict
cloud separation requirements and have at least 3 mi of visibility so
that they may sufficiently be able to see and avoid other traffic. In addition, all traffic operating within Class C airspace must have established
radio communication with air traffic control. The shape of Class C airspace is also in the form of an upside down wedding cake, extending
from the surface to typically 4000 ft AGL around the inner 5-nm radius
around the airport, and from 1000–2000 ft to 4000 ft AGL from 5 to
10 nm from the airport. Figure 3-4 provides an illustration of Class C
airspace surrounding the Daytona Beach International Airport, depicted
by a two concentric rings of radii 5 and 10 mi around the airport.
Class D airspace is found within a 5-mi radius of an airport with
an operating air traffic control tower, extending from the surface to
typically 2500 ft AGL. The purpose of Class D airspace is to provide
an area of air traffic control authority to controllers in the airport’s
control tower, who are responsible for the safe separation of arriving
and departing aircraft to and from the airport. Aircraft operating
under VFR flight rules are allowed to operate within Class D airspace
as along as they establish communication with the air traffic controllers in the tower. When an airport’s control tower is in operation, the
airport is said to be a “controlled” airport. When the airport’s tower is
not operational, the airport is considered “uncontrolled” and Class D
airspace is no longer active. Airports without a control tower are considered “uncontrolled airports,” as well. Figure 3-5 illustrates Class D
airspace surrounding the Southwest Georgia Regional Airport in
Albany, Georgia, depicted by a dashed 5-mi radius circle around the
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-4
Class C airspace around Daytona Beach International Airport.
airport. The outer shaded ring depicts Class E airspace beginning at
700 ft above ground level.
Class E airspace is found in several locations with the purpose of
providing areas of at least “passive” control for airplanes flying in
areas of low altitude but moderate traffic activity, on defined air routes,
FIGURE 3-5 Class D airspace around Southwest Georgia Regional Airport,
Albany, Georgia.
105
106
Airport Planning
as well as those flying on instrument-based approach and departure
procedures to or from an airport. Specifically, Class E airspace exists in
most parts of the United States, from the surface, 700 ft AGL, or 1200 ft
AGL to 14,500 ft AGL, and 3 nm surrounding the nation’s airways.
Any airspace that does not fall within Class A, B, C, D, or E airspace is considered Class G, or uncontrolled airspace. This airspace is
found only at very low altitudes (typically less than 700 or 1200 ft
AGL) or in rural areas of low volume air traffic. Within Class G airspace, aircraft may move freely as long as there is sufficient visibility
(1 mi during day hours, 3 mi during night hours, 5 mi day or night
when above 10,000 ft AMSL) to see and avoid other air traffic.
Within the National Airspace System are a number of special use
airspace classifications. Some of these define permanent location of
special use or restricted activity, others define locations where flight
operations are restricted for security or other reasons.
Prohibited areas are defined within the NAS as areas prohibited
to any civil aviation activity. These areas are typically defined
around highly sensitive locations, such as the White House in
Washington, D.C.
Restricted areas are defined within the NAS as areas where regular,
but not constant, sensitive operations occur, precluding the safe passage of civil aircraft. These areas, such as around the Kennedy Space
Center on the east coast of Florida, will periodically restrict civilian
access when sensitive activities are occurring.
Military operations areas (MOAs) are defined as areas with periodic military aviation or other activity. These areas may be entered
only by permission from air traffic control, which coordinates with
the military for civilian use.
Temporary flight restrictions (TFRs) are defined as areas that temporarily restrict or prohibit most civil aviation operations for reasons of
national security. TFRs are implemented with little advance notice for
a variety of reasons, ranging from protecting nuclear power facilities,
to national sporting events, to the travels of the President of the
United States. Oftentimes, the activation of a TFR will have serious
impacts on the accessibility of an airport to the aviation system.
Figure 3-6 provides an illustration of multiple classes of airspace
within the same region, including Class E airspace under PalatkaLarkin Airport and restricted areas within a military operations area
south of the airport. Restricted use airspace presents challenges to
airport planners seeking maximum efficiency of air traffic to and
from the airfield.
Airways
Aircraft flying from one point to another have traditionally followed
designated routes. In the United States these are referred to as victor
airways and jet routes. These routes have evolved over time as discussed below.
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-6
Florida.
MOAs and restricted areas south of Kay Larkin Airport, Palatka,
Colored Airways
The earliest airways, created in the 1920s were initially given a color
designation on aeronautical charts and described by their color. The
trunk lines east and west were green, trunk lines north and south
were amber, secondary lines east and west were red, and secondaries
north and south were blue. Each of these colored airways was then
given a number, such as green 3, red 4, etc. The numbering for the
airways began at the Canadian border and the Pacific Coast, then
progressed to the south and east. These airways were then assigned
an altitude level, which for green and red was at odd-thousand feet
eastbound and at even-thousand feet westbound. On the amber and
blue airways northbound, odd-thousand-foot levels were assigned,
and southbound even-thousand-foot levels were assigned. These airways were delineated on the ground by low-frequency mediumfrequency (LF/MF) four course radio ranges. The colored airways
were phased out as aircraft became equipped to use the victor airways
in the late 1940s.
107
108
Airport Planning
Victor Airways
Following the development of the LF/MF four course radio ranges
the routes now known as the victor airways were established. The
victor airways are delineated on the ground by very high frequency
omnirange radio equipment (VORs). Each VOR station has a discrete
radio frequency to which a pilot could tune a navigational radio and
thus be able to maintain a course from one VOR to the next. The numbering system for these airways is even numbers east and west, odd
numbers north and south. The advantages of the victor airways were
that the VORs were relatively free of static and it is much easier for a
pilot to determine air position relative to a VOR station than with the
LF/MF four course radio range. Victor airways are designated on
aeronautical charts as V-1, V-2, etc. The airway includes the airspace
within parallel lines 4 mi each side of the centerline of the airway. If
two VORs delineating an airway are more than 120 mi apart, the airspace included in the airway is as indicated for jet routes.
Jet Routes
With the introduction of commercial jet aircraft in 1958, the altitudes
at which these aircraft flew increased significantly. At higher altitudes
the number of ground stations (VORs) required to delineate a specific
route is smaller than at lower altitudes because the signal is transmitted on a line of sight. Therefore there was no need to clutter the high
altitude routes with all the ground stations required for low altitude
flying. All the routes in the continental United States could be placed
on one chart. These were established what are known as jet routes.
Although in one sense these routes are airways, they are not referred
to as such. Today both victor airways and jet routes exist. Thus the jet
routes are delineated by the same aids to navigation on the ground
(VORs) as are victor airways but fewer stations are used. Victor airways extend from 1200 ft above the terrain to, but not including,
18,000 ft AMSL. Jet routes extend from 18,000 ft to 45,000 ft AMSL.
Above 45,000 ft there are no designated routes and aircraft are handled on an individual basis. The numbering system for the jet routes
is the same as for the victor airways. Jet routes are designated on
aeronautical charts as J-1, J-2, etc.
Area Navigation
For many years all aircraft were required to fly on designated routes,
airways, or jet routes. That is, all aircraft had to fly from one VOR to
the next VOR since the VORs delineate the airways and jet routes.
This required the funneling of all traffic on the designated routes that
resulted in congestion on certain routes. Also the designated routes
were often not the shortest distance between two points, resulting in
additional fuel consumption, flight time, and cost. Furthermore, if the
A i r Tr a f f i c M a n a g e m e n t
designated route penetrates into an area of thunderstorms, aircraft
have to be vectored around the storm by controllers on the ground.
This imposed an extra workload on the controllers that is compensated for by the use of the severe weather avoidance program (SWAP).
Despite these inefficiencies, the vast majority of transient aviation
still fly along the victor airways and jet routes. This trend, however,
has begun to change dramatically since the beginning of the twentyfirst century, with the proliferation of GPS based navigation systems,
under what is known as RNAV.
Area navigation, RNAV, is a method of aircraft navigation that
permits aircraft operation on any desired course within the coverage of station-referenced navigational signals or within the limits of
a self-contained system capability. Area navigation routes are direct
routes, based upon the area navigation capability of aircraft,
between waypoints defined in terms of latitude and longitude coordinates, degree and distance fixes, or offsets from established routes
and airways.
RNAV is possible due to the proliferation of onboard aircraft
technologies that take advantage of the global positioning system
(GPS). GPS is based on 24 satellites located approximately 12,000 mi
about the earth in a geostatic orbit. Technology that references an
aircraft’s position in relation to these satellites allows an aircraft to
navigate by referencing its position to a detailed database that identifies airports, waypoints, terrain, and man-made infrastructure.
Enhancements to the accuracy of the GPS system, with technologies
such as the wide area augmentation system (WAAS) have made it
possible for the air traffic control system to approve defined approaches
to airport runways with far greater accuracy than with traditional
radio-frequency-based systems.
Area navigation provides a more flexible routing capability that
allows for better utilization of the airspace. The greater utilization
reduces delays in the airspace and results in more economical operation of the aircraft. For example, routes parallel to the designated
routes from one VOR to another can be established without requiring
additional aids to navigation on the ground. Another example is the
establishment of a more direct route from one point to another by
establishing waypoints that provide for a shorter trip. Routing around
a thunderstorm without continuous radar guidance from the ground
is another example.
Area navigation is not limited to the horizontal plane but can also
be utilized in the vertical plane, termed VNAV. It can also include a
time reference capability. A properly equipped aircraft could arrive at
a specified point in space, called a fix, with no need for ground vectoring or directions and could additionally be at that point at a specified
altitude and time. This is a four-dimensional capability giving latitude, longitude, altitude, and time (4D RNAV). Thus area navigation
109
110
Airport Planning
FIGURE 3-7 Airways, navigational aids, and airports as depicted on an IFR en
route low altitude navigational chart.
has the potential of increasing airspace capacity, enhancing safety,
and reducing the workload of the pilot and the air traffic controller.
As part of RNAV enhancements, the FAA began establishing
T-routes as alternative routes to the victor airways for those aircraft
equipped with GPS systems. These T-routes were established to provide aircraft with more direct routing, often around congested traffic
areas such as Class B airspace and areas where victor airways intersect, often in the vicinity of a VOR station.
Figure 3-7 illustrates a portion of airspace as depicted in an IFR en
route low altitude chart, published by the FAA’s National Aeronautical Charting Office. This figure depicts both victor airways (identified
by V followed by a route number) and T-routes (identified by a T followed by a route number), as well as the locations of airports, classes
of airspace (such as the shaded area around Jacksonville International
Airport), VOR stations (such as Taylor, Cecil, and Craig), and other
navigational facilities. It is recommended that airport planners
become familiar with understanding the information provided on
this and other aeronautical charts.
Air Traffic Separation Rules
Air traffic rules governing the minimum separation of aircraft in the
vertical, horizontal or longitudinal, and lateral directions are established in each country by the appropriate government authority. The
current rules described in this text are those that are prescribed by the
A i r Tr a f f i c M a n a g e m e n t
FAA for use in the United States. The separation rules are prescribed
for IFR operations and these rules apply whether or not IMC conditions prevail. Minimum separations are a function of aircraft type,
aircraft speed, availability of radar facilities, navigational aids, and
other factors such as the severity of wake vortices [3].
Vertical Separation in the Airspace
The minimum vertical separation of aircraft outside of the terminal
area from the ground up to and including 41,000 ft AMSL is 1000 ft.
In 2005, vertical separation minimums above 29,000 ft AMSL were
reduced from 2000 to 1000 ft under the reduced vertical separation
minima (RVSM) program. Implementation of this program allowed
for additional jet routes thereby increasing the capacity within the
NAS. Within a terminal area a vertical separation of 500 ft is maintained between aircraft, except that a 1000-ft vertical separation is
maintained below a heavy aircraft.
Assigned Flight Altitudes
To formalize the separation of air traffic in the airspace, air traffic
control assigns flight altitudes to aircraft based on their direction, or
more precisely magnetic heading, of flight, and whether or not they
are flying under VFR versus IFR rules.
Aircraft flying under IFR are typically assigned altitudes of oddthousand feet (i.e., 3000 ft, 5000 ft, etc.) AMSL while on an easterly
heading (magnetic compass heading of 0° to 179°) and even-thousand
feet (i.e., 4000 ft, 6000 ft, etc.) while on a westerly heading (magnetic
compass heading of 180° to 359°). Between 29,000 ft AMSL (FL 290)
and 41,000 ft AMSL (FL 410), aircraft are assigned a flight level of
either FL 290, FL 330, FL 370, or FL 410 when traveling on an easterly
heading, and either FL 310, FL 350, FL 390 when traveling on a westerly heading. If an aircraft is RVSM certified, it may be assigned an
RVSM altitude of FL 300, 320, 340, etc. between FL 290 and FL 410.
Aircraft flying under VFR above 3000 ft AMSL are typically
assigned altitudes of odd-thousand feet plus 500 ft (i.e., 3500 ft, 5500 ft,
etc.) while on an easterly heading, and even-thousand feet plus 500 feet
(i.e., 4500 ft, 6500 ft, etc.) while on a westerly heading (magnetic compass heading of 180° to 359°). Above 29,000 ft (FL 290), VFR traffic is
assigned every-other even or odd thousand (FL 290, FL 330, etc. if
traveling on an easterly heading, and FL 320, FL 360, etc. if traveling
on a westerly heading). It should be noted that above FL 180, all traffic is required to be on an IFR flight plan.
Longitudinal Separation in the Airspace
The minimum longitudinal separation depends on a number of factors. Among the most important are aircraft size, aircraft speed, and
the availability of radar for the control of air traffic. For the purposes
111
112
Airport Planning
of maintaining aircraft separations aircraft are classified by the FAA
as heavy, large, or small based upon their maximum gross takeoff
weight (MGTOW). Heavy aircraft are classified as those aircraft
which have a MGTOW of 300,000 lb or more. Large aircraft are as
those aircraft which have a MGTOW of in excess of 12,500 lb but less
than 300,000 lb. Small aircraft are as those aircraft which have a
MGTOW of 12,500 lb or less. Aircraft size is related to wake turbulence. Heavy aircraft create trailing wake vortices which are a hazard
to lighter aircraft following them.
The minimum longitudinal separations en route are expressed in
terms of time or distance as follows:
1. For en route aircraft following a preceding en route aircraft, if
the lead aircraft maintains a speed at least 44 kn faster than
the trail aircraft, 5 mi between aircraft using distance measuring equipment (DME) or area navigation (RNAV) and 3 minutes between all other aircraft
2. For en route aircraft following a preceding en route aircraft, if
the lead aircraft maintains a speed at least 22 kn faster than
the trail aircraft, 10 mi between aircraft using DME or RNAV
and 5 min for all other aircraft
3. For en route aircraft following a preceding en route aircraft, if
both aircraft are at the same speed, 20 mi between aircraft
using DME or RNAV and 10 min for all other aircraft
4. When an aircraft is climbing or descending through the altitude of another aircraft, 10 mi for aircraft using DME or
RNAV if the descending aircraft is leading or the climbing
aircraft is following and 5 min for all other aircraft
5. Between aircraft in which one aircraft is using DME or RNAV
and the other is not, 30 mi
Minimum longitudinal separations over the oceans is normally
10 minutes for supersonic flights and 15 minutes for subsonic flights
but in some locations it can be slightly more or less than this value [3].
When the aircraft mix is such that wake turbulence is not a factor
and radar coverage is available, the minimum longitudinal separation for two aircraft traveling in the same direction and at the same
altitude is 5 nm, except that when the aircraft are in the terminal environment within 40 nm of the radar antenna the separation can be
reduced to 3 nm. For this reason the minimum spacing in the terminal area is 3 nm because the airport is almost always within 40 nm of
a radar antenna. Under certain specified conditions a separation
between aircraft on final approach within 10 nm of the landing runway may be reduced to 2.5 nm [3].
If wake turbulence is a factor, the minimum separation in the terminal area between a small or large aircraft and a preceding heavy
A i r Tr a f f i c M a n a g e m e n t
Lead
Aircraft Type
VFR* Trail Aircraft Type
Heavy
Large
Small
IFR (Wake Vortex) Trail
Aircraft Type
Heavy
Large
Small
Heavy
2.7
3.6
4.5
4.0
5.0
6.0
Large
1.9
1.9
2.7
3.0
3.0
4.0
Small
1.9
1.9
1.9
3.0
3.0
3.0
∗These are shown to appropriately represent these operations and are not regulatory in
nature.
Source: Federal Aviation Administration [18].
TABLE 3-1 Horizontal Separation in Landing for Arrival-Arrival Spacing of Aircraft
on Same Runway Approaches in VFR and IFR Conditions (nautical miles)
aircraft is 5 nm. The spacing between two heavy aircraft following
each other is 4 nm. The spacing between a heavy aircraft and a preceding large aircraft is 3 nm.
For landing aircraft when wake turbulence is a factor, the longitudinal separation is increased between a small aircraft and a preceding
large aircraft to 4 mi and between a small aircraft and a preceding
heavy aircraft to 6 mi.
The IFR separation rules for consecutive arrivals on the same runway which are used when wake vortices are a factor are shown in
Table 3-1. The VFR and IFR separation rules for consecutive departures from the same runway are expressed in terms of time and these
are shown in Table 3-2.
Lateral Separation in the Airspace
The minimum en route lateral separation below 18,000 ft MSL is 8 nm,
and at and above 18,000 ft MSL the minimum en route lateral separation
VFR* Trail Aircraft Type
IFR Trail Aircraft Type
Lead
Aircraft Type
Heavy
Large
Small
Heavy
Large
Small
Heavy
90
120
120
120
120
120
Large
60
60
50
60
60
60
Small
50
45
35
60
60
60
∗These are shown to appropriately represent these operations and are not regulatory in
nature.
Source: Federal Aviation Administration [18].
TABLE 3-2
Separation for Same Runway Consecutive Departures in VFR and IFR
Conditions (seconds)
113
114
Airport Planning
is 20 nm. Over the oceans the separation varies from 60 to 120 nm
depending on location [3].
Navigational Aids
Aids to navigation, known as NAVAIDS, can be broadly classified
into two groups, ground-based systems and satellite-based systems.
Each system is complimented by systems installed in the cockpit.
Ground-Based Systems
Nondirectional Beacon
The oldest active ground-based navigational aid is the nondirectional
beacon (NDB). The NDB emits radio frequency signals on frequencies between 400 and 1020 Hz modulation. NDBs are typically
mounted on a pole approximately 35 ft tall. They may be located on
or off airport property, at least 100 ft clear of metal buildings, power
lines, or metal fences. While the NDB is quickly being phased out in
the United States, it is still a very common piece of navigational
equipment in other parts of the world, particularly in developing
nations. Figure 3-8 provides an illustration of an NDB.
Aircraft navigate using the NDB by referencing an automatic
direction finder (ADF) located on the aircraft’s panel. The ADF simply points toward the location of the NDB. Figure 3-9 illustrates an
ADF system.
FIGURE 3-8
Nondirectional beacon.
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-9
Automatic direction finder.
Very High Frequency Omnirange Radio
The advances in radio and electronics during and after World War II
led to the installation of the very high frequency omnirange (VOR)
radio stations. These stations are located on the ground and send out
radio signals in all directions. Each signal can be considered as a
course or a route, referred to as a radial that can be followed by an
aircraft. In terms of 1° intervals, there are 360 courses or routes that
are radiated from a VOR station, from 0° pointing toward magnetic
north increasing to 359° in a clockwise direction. The VOR transmitter station is a small square building topped with what appears to be
a white derby hat. It broadcasts on a frequency just above that of FM
radio stations. The very high frequencies it uses are virtually free of
static. The system of VOR stations establish the network of airways
and jet routes and are also essential to area navigation. The range of a
VOR station varies but is usually less than 200 nm. A typical VOR
beacon is illustrated in Fig. 3-10.
Aircraft equipped with a VOR receiver in the cockpit have a dial
for tuning in the desired VOR frequency. A pilot can select the VOR
radial or route he wishes to follow to the VOR station. In the cockpit
there is also an omnibearing selector (OBS) which indicates the heading of the aircraft relative to the direction of the desired radial and
whether the aircraft is to the right or left of the radial. An illustration
of an OBS is provided in Fig. 3-11.
Distance Measuring Equipment
Distance measuring equipment (DME) has traditionally been installed
at VOR stations in the United States. The DME shows the pilot the
115
116
Airport Planning
FIGURE 3-10 VOR beacon on the airfield at Ronald Reagan Washington
National Airport.
slant distance between the aircraft and a particular VOR station. Since
it is the air distance in nautical miles that is measured, the receiving
equipment in an aircraft flying at 35,000 ft directly over the DME station would read 5.8 nm.
An en route air navigation aid which best suited the tactical needs
of the military was developed by the Navy in the early 1950s. This aid
is known as TACAN, which stands for tactical air navigation. This aid
combines azimuth and distance measuring into one unit instead of two
and is operated in the ultra-high-frequency band. As a compromise
between civilian and military requirements, the FAA replaced the DME
100°
OBS knob turns the
compass card, here
set to 100
FIGURE 3-11
Omnibearing selector.
TO/FROM indicator
showing TO
CDI needle swung
3 dots left, meaning
you are 6° right of
the 280 radial
A i r Tr a f f i c M a n a g e m e n t
TVOR
250'
Tax
i
wa
y
500'
Runway
500'
ay
nw
Ru
TVOR location standards.
FIGURE 3-12
portion of its VOR facilities with the distance measuring components
of TACAN. These stations are known as VORTAC stations. If a station
has full TACAN equipment, both azimuth and distance measuring
equipment, and also VOR, it is designated as VORTAC.
NDB and VOR systems are often located on airport airfields. The
location of these systems on airport, known as TVORs, are significant
to airport planners and designers, as the location of other facilities,
such as large buildings, particularly constructed of metal, may
adversely affect the performance of the navaid.
As illustrated in Fig. 3-12, TVORs should be located at least 500 ft
from any runways and 250 ft from any taxiways. Any structures or
trees should be located at least 1000 ft from the TVOR antenna. There
should also be a clearance angle of at least 2.5° for any structures and
2.0° for any trees beyond 1000 ft, as illustrated in Fig. 3-13.
Tree
Clearance
Angle
Antenna Shelter
2°
Counterpoise
2.5°
1.2°
1,000' Min
(300 M)
200' Min Radius
(80 M)
Max Allowable Slope 4%
FIGURE 3-13
TVOR clearance requirements.
Antenna
Height
16"–17"
(5 M)
Clearance Angles
2.5° for Wooden Structures
1.2° for Metal Structures
117
118
Airport Planning
Air Route Surveillance Radar
A long-range radar for tracking en route aircraft has been established
throughout the continental United States and in other parts of the
world. While in the United States there is complete radar coverage in
the 48 contiguous states, this is not the case elsewhere in the world.
These radars have a range of about 250 nm. Strictly speaking radar is
not an aid to navigation. Its principal function is to provide air traffic
controllers with a visual display of the position of each aircraft so
they can monitor their spacings and intervene when necessary. However, it can be and is used by air traffic controllers to guide aircraft
whenever this is necessary. For this reason it has been included as an
aid to navigation.
The VOR and NDB, often combined with radar-based surveillance
from air traffic control, have traditionally been used in both en route
navigation and for navigation on approach to landing at an airport.
Navigation on approach to an airport using these ground-based systems is performed by following predetermined, published, approach
procedures. These procedures are often updated and published by the
FAA in the form of approach charts. Figure 3-14 provides an example
of an approach chart depicting an approach procedure using an NDB
as an aid to navigation, while Fig. 3-15 illustrates a similar approach
using a VOR as the primary aid to navigation. It is strongly recommended that the airport planner understand the information provided
in these charts. Approaches based on NDB and VOR navaids are considered “nonprecision” approaches, as they provide lateral navigation
assistance but not vertical navigation. That is, these instruments may
be referenced to determine which direction to fly when approaching an
airport, but do not provide instrument-based guidance in determining
the appropriate altitude or descent rate on approach.
Instrument Landing System
Until the recent proliferation of published navigation procedures which
rely on the satellite based GPS system, the instrument landing system
(ILS) was the only ground-based system certified to provide both lateral and vertical guidance to aircraft on approach to an airport, and as
of 2008 is the only navigational aid certified by the FAA to provide
“precision” navigation for aircraft, and is still the most widely used
method of approach navigation at the world’s larger airports.
An ILS system consists of two radio transmitters located on the
airport. One radio beam is called the localizer and the other the glide
slope. The localizer indicates to pilots whether they are left or right of
the correct alignment for approach to the runway. The glide slope
indicates the correct angle of descent to the runway. Glide slopes are
in the order of from 2°–3° to 7.5°.
In order to further help pilots on their ILS approach, up to three
low-power fan markers called ILS markers are usually installed so
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-14 NDB approach.
that they may know just how far along the approach to the runway
they have progressed. The first is called the outer marker (LOM) and
is located about 3.5 to 5 mi from the end of the runway. The middle
marker (MM) is located about 3000 ft from the end of the runway. On
119
120
Airport Planning
FIGURE 3-15 VOR approach.
some ILS systems, an additional marker called the inner marker (IM)
is located 1000 ft from the end of the runway. When the plane passes
over a marker, a light goes on in the cockpit and a tone sounds. The
configuration of the ILS system is shown in Fig. 3-16.
Localizer array
Glide-slope array
Point of
intersection,
runway and glide
path extended
Amber light
Middle marker beacon
3000–4000 ft
(900–1200 m)
Localizer modulation
frequency
200 ft (60 m)
Purple light
4–
7
m
i(
Outer marker beacon
6–
11
km
)
Glide slope
modulation
frequency
0.7°
0.7°
3.0°–6.0°
3° above
horizontal (optimum)
121
FIGURE 3-16 ILS system configuration.
122
Airport Planning
The localizer consists of an antenna, which is located on the extension of the runway centerline approximately 1000 ft from the far end
of the runway, and a localizer transmitter building located about 300 ft
to one side of the runway at the same distance from the end of the
runway as the antenna. The glide slope facility is placed 750 to 1250 ft
down the runway from the threshold and is located to one side of the
runway centerline at a distance which can vary from 400 to 650 ft. The
functioning of the localizer and the glide slope facility is affected by
the close proximity of moving objects such as vehicular and aircraft
traffic. During inclement weather the use of the ILS critical areas
inhibit aircraft and vehicles from entering into areas that would
impede an aircraft inside of the outer marker from receiving a clear
signal. Stationary objects nearby can also cause a deterioration of signals. Abrupt changes of slope in proximity of the antennas are not
permitted or the signal will not be transmitted properly. Another limitation of the ILS is that the glide slope beam is not reliable below a
height of about 200 ft above the runway.
As with VOR and NDB systems, the localizer and glide slope
components of the ILS are highly sensitive to their proximity to surrounding objects that may interfere with their radio signals. As such,
there are specific restrictions to construction in the immediate vicinity of these systems.
ILS systems may also be accompanied by runway visual range
(RVR) equipment, which provide a measurement of lateral visibility
to a pilot. RVR systems determine the distance a pilot should be able
to see down the runway, given current atmospheric conditions and
existing lighting systems. Depending on the type of RVR system
installed, pilots can safely approach to land on a runway using ILS
navigation in varying levels of cloud ceiling levels and horizontal visibility. Table 3-3 provides the ceiling and visibility levels for ILS systems equipped with RVR. Figure 3-17 illustrates a published approach
using an ILS.
The most critical point of approach to landing comes when the
aircraft breaks through the overcast and the pilot must change from
instrument to visual conditions. Sometimes, only a few seconds are
ILS Category
Cloud Ceiling
Visibility (RVR)
I
200 ft
1,800–2,400 ft
II
100 ft
1,200 ft
IIIa (auto land)
0–100 ft
700 ft
IIIb (auto rollout)
0–50 ft
150 ft
IIIc (auto taxi)
0 ft
0 ft
TABLE 3-3 ILS Capabilities
A i r Tr a f f i c M a n a g e m e n t
FIGURE 3-17
Published ILS approach procedure.
available for the pilot to make the transition and complete the landing. To aid in making this transition, lights are installed on the
approach to and on the runways. These are generally termed approach
lighting systems (ALS). More details concerning these systems are
contained in the chapter on signing, marking, and lighting.
123
124
Airport Planning
Airport Surface Detection Equipment
In use in many of the busier airports within the United States and
elsewhere, specially designed radar called airport surface detection
equipment (ASDE), often referred to as ground radar, has been
developed to aid the controller in regulating traffic on the airport.
The system gives the air traffic controller in the control tower a pictorial display of the runways, taxiways, and terminal area with radar
indicating the position of aircraft and other vehicles moving on the
surface of the airport.
ASDE technologies are most commonly available in two forms.
The airport movement area safety system (AMASS) integrates third
generation (ASDE-3) ground-based radar systems with audio and
visual warning systems to prevent runway incursions on the airfield.
ASDE-X, a system that integrates ASDE technology with transponder
systems to identify the aircraft operating on the aircraft, has been
employed at less busy commercial service airports throughout the
United States. These systems are monitored by air traffic management personnel in the airport’s ATCT.
Satellite-Based Systems: Global Positioning System
Perhaps the greatest impact on air traffic management since the
beginning of the twenty-first century has been the development,
acceptance, and proliferation of navigational procedures which rely
on the global positioning system.
The global positioning system (GPS) is a satellite-based radio
positioning and navigation system. The system is designed to provide highly accurate position and velocity information on a continuous global basis to an unlimited number of properly equipped users.
The system is unaffected by weather and provides a common worldwide grid reference system. The GPS concept is predicated upon
accurate and continuous knowledge of the spatial position of each
satellite in the system with respect to time and distance from a transmitting satellite to the user. The GPS system consists of 24 satellites in
near-circular orbit about the earth. GPS receivers onboard aircraft
automatically select the appropriate signals from typically four satellites which are in view of the receiver and translate these signals into
a three-dimensional position, and when the receiver is in motion,
velocity.
GPS was developed by the United States military to aid in reconnaissance and strategic operations. Under military operations, signals transmitted from the orbiting GPS satellites were encrypted to
reduce the accuracy of positioning for nonauthorized users. This policy became known as “selective availability.” However, on May 1,
2000, President Bill Clinton ordered the removal of selective availability, allowing the civilian world to take advantage of GPS positioning accuracy on the order of 1 to 3 m. This level of accuracy has been
A i r Tr a f f i c M a n a g e m e n t
deemed sufficient to allow aircraft to navigate using properly
equipped GPS receivers for both en route navigation and approaches
to airports, in both VFR and IFR conditions.
In the first decade of the twenty-first century, the proliferation of
GPS-based air navigation systems has been dramatic, to the point
where the use of traditional ground-based navigation aids such as the
NDB and VOR is becoming obsolete. GPS navigation systems have
become available as both in-panel fixed navigation systems, and portable units, and have become widely used in many areas of society
outside of aviation.
As Fig. 3-18 illustrates, GPS systems, particularly enhanced with
comprehensive databases of area terrain, landmarks, and airport
infrastructure, provide pilots with “virtually visual conditions” and
the ability to navigate from origin to destination without any reliance
on traditional ground-based analog navigational aids.
GPS-based RNAV approaches have been refined with improving
technology, known as the wide area augmentation system (WAAS),
and training to allow aircraft to approach airports using very precise
navigation procedures. These approaches, known as RNP (required
navigation performance), have allowed aircraft to navigate around
such obstacles as mountainous terrain and security sensitive areas,
resulting in a more efficient use of airport runways. Juneau, Alaska
and Washington, D.C. are airports that have benefited from these
enhancements in air traffic control. An example RNP approach is
illustrated in Fig. 3-19.
FIGURE 3-18 Aircraft GPS-based navigation equipment (Cirrus Aircraft Inc.).
125
126
Airport Planning
FIGURE 3-19 RNP approach into Ronald Reagan Washington National Airport,
Washington, D.C.
ADS-B
Further enhancements to the air traffic management system include
the use of advanced digital data-link systems, known as automated
dependent surveillance. ADS-address (ADS-A) systems send digitally
transmitted information between specific aircraft and ADS-broadcast
A i r Tr a f f i c M a n a g e m e n t
Global Navigation
Satellite
System
ADS-B
ADS-B
Collision
Avoidance
ADS-B
Surveillance
Radar
Modes
Air Traffic
Management
ADS
Receiver
FIGURE 3-20 Rendering of ADS-B system (Atcmonitor.com).
(ADS-B) systems broadcast information to all equipped aircraft and air
traffic management facilities, identifying their locations to other traffic
in the system, providing the added ability to safety avoid collisions
even in poor visibility conditions. Originally tested in Alaska between
2000 and 2003, ADS-B is quickly becoming a standard component of air
traffic navigation systems in the United States. A rendering of the
ADS-B system is Fig. 3-20.
The Modernization of Air Traffic Management
Despite the proliferation of GPS-based navigation since the beginning of
the twenty-first century, the principal aids for the control of air traffic by
air traffic management personnel are still voice communication and
radar. Air traffic controllers monitor the spacing between aircraft on the
radarscope and instruct pilots by means of voice communication.
Radar returns appear on the radarscope as small blips. These are
reflections from the aircraft body. Primary radar requires the installation
of rotating antennas on the ground and the range of the primary radar is
a function of its frequency. Secondary radar consists of a radar receiver
and transmitter on the ground that transmits a coded signal to an aircraft
if that aircraft has a transponder. A transponder is an airborne receiver
and transmitter which receives the signal from the ground and responds
by returning a coded reply to the interrogator on the ground. The coded
reply normally contains information on aircraft identity and altitude.
Information from primary and secondary radar returns are provided to air traffic controllers via an alphanumeric display on their
radar “scopes,” as illustrated in Fig. 3-21. The first line shows the
127
128
FIGURE 3-21
Air route surveillance radar, Atlanta TRACON.
A i r Tr a f f i c M a n a g e m e n t
identity of the aircraft, the second line its altitude and ground speed,
and the third line gives the beacon code transponder number and the
aircraft track number. To be able to have this information presented
on the radarscope, the aircraft must carry a mode-C or mode-S transponder that has the capability of altitude reporting along with aircraft identity. All commercial airline aircraft carry a transponder,
which satisfies the requirement for reporting altitude. Further, all aircraft flying in Class A, B, or C airspace are required to have an operating transponder onboard.
NextGen
For more than 50 years air traffic control systems have gone through
a number of incremental technological enhancements, such as
enhanced radar capabilities, automated flight service systems, and
ground-based navigation systems. Despite these upgrades, it has
been widely recognized that the traditional radar and analog-based
communication system will not be sufficient to accommodate the
increasing demands on the system in the twenty-first century.
As part of the Vision 100 Century of Aviation Reauthorization Act
of 2003, the U.S. federal government called for a complete transformation of the national airspace system and a modernization of its air
traffic control facilities. This modernization has come to be known as
the “next generation air traffic system” or NextGen. Through the act,
Congress directed the formation of a “Joint Planning and Development Office” (JPDO) to facilitate the mammoth task of converting the
current system to a fully automated, digital, satellite-based air traffic
management system. The JPDO comprises of representatives from
the FAA, NASA, The U.S. Departments of Transportation, Defense,
Homeland Security, Commerce, and the White House Office of
Science and Technology Policy, and directed to develop a next generation air traffic system that is technologically advanced and fully
integrates the interests of all who use the nation’s aviation system.
NextGen will focus on making the satellite-based GPS system
and digital data communications the backbone of air traffic management. Integrated into NextGen are GPS, WAAS, and ADS-B technology to allow for digital surveillance of air traffic between both
ground-based air traffic management facilities as well as among
aircraft themselves. In addition to ADS-B technology, NextGen features
the following capabilities, as described by the FAA:
SWIM
System wide information management (SWIM) provides the infrastructure and services to deliver network-enabled information access
across the NextGen air transportation operations. As an early opportunity investment, SWIM will provide high-quality, timely data to
many users and applications—extending beyond the previous focus
129
130
Airport Planning
on unique, point-to-point interfaces for application-to-application
data exchange. By reducing the number and types of interfaces and
systems, SWIM will reduce redundancy of information and better
facilitate multiagency information-sharing. SWIM will also enable
new modes of decision making, as information is more easily accessed
by all stakeholders affected by operational decisions.
NextGen Data Communications
NextGen data communications will provide for two-way digital communications between air traffic controllers and pilots for air traffic
control clearances, instructions, and other advisories. In addition,
digital communications will provide broadcast text-based and graphical advisory information such as weather reports and notices to airmen without relying on voice communications.
NextGen Enabled Weather
The NextGen network enabled weather (NNEW) will serve as the
core of the NextGen weather support services and provide a common
weather picture across the national airspace system. These services
will, in turn, be integrated into other key components of NextGen
required to enable better air transportation decision making. It is
anticipated that tens of thousands of global weather observations and
sensor reports from ground-, airborne-, and space-based sources
would fuse into a single national weather information system,
updated as needed in real time.
NextGen is due to be a phased transformation of the NAS through
2025 at an estimated cost of $20 to $25 billion. It should be noted the
early stages of NextGen development have been very volatile with
regard to the selection of technology platforms on which to base the
future air traffic management system, and it should be expected that
further developments in technology will result in variations to current system plans. As such, it is imperative that the airport planner
keep up with current progress. The JPDO and the FAA frequently
update their Internet sites with NextGen system progress.
References
1. Airport Design, Advisory Circular AC150/5300-13, Federal Aviation
Administration, Washington, D.C., 2008.
2. Air Route Traffic Control, Airway Planning Standard Number Two, Order 7031.3,
Federal Aviation Administration, Washington, D.C., September 1977.
3. Air Traffic Control Handbook, Order 7110.65G, Federal Aviation Administration,
Washington, D.C., March 1992.
4. Air Traffic Management Plan (ATMP) Program, Development and Control Procedures,
Order No. 7000.3, Federal Aviation Administration, Washington, D.C., February
1988.
5. An Analysis of the Requirements for, and the Benefits and Costs of the National Microwave
Landing System (MLS), Office of Systems Engineering Management, Report No.
FAA-EM-80-7, Federal Aviation Administration, Washington, D.C., June 1980.
A i r Tr a f f i c M a n a g e m e n t
6. Aviation System Capacity Plan 1991-92, Report No. DOT/FAA/ASC-91-1, U.S.
Department of Transportation, Federal Aviation Administration, Washington,
D.C., 1991.
7. Chicago Delay Task Force Technical Report, vol. 1: Chicago Airport/Airspace
Operating Environment, Landrum and Brown Aviation Consultants, Chicago,
Ill., April 1991.
8. Civil Aviation Research and Development Policy Study, Department of Transportation
and National Aeronautics and Space Administration, Washington, D.C., March
1971.
9. Designation of Federal Airways, Area Low Routes, Controlled Airspace, Reporting
Points, Jet Routes and Area High Routes, Part 71, Federal Aviation Regulations,
Federal Aviation Administration, Washington, D.C., February 1992.
10. Enroute High Altitude—U.S., Flight Information Publication, National Ocean
Survey, National Oceanic and Atmospheric Administration, Department of
Commerce, Washington, D.C., December 1975.
11. Establishment of Jet Routes and Area High Routes, Part 75, Federal Aviation
Regulations, Federal Aviation Administration, Washington, D.C., December
1991.
12. FAA Long-Range Aviation Projections, Fiscal Years 2004-2015, Report No. FAAAPO-92-4, Office of Aviation Policy, Plans, and Management Analysis, Federal
Aviation Administration, Washington, D.C., May 1992.
13. FAA Report on Airport Capacity, The MITRE Corporation, Report FAA-EM-74-5,
Federal Aviation Administration, Washington, D.C., 1974.
14. “Future ATC Technology Improvements and the Impact on Airport Capacity,”
R. M. Harris, The MITRE Corporation, Air Transportation Systems Division,
McLean, Va.
15. “Future System Concepts for Air Traffic Management, W. E. Simpson, Office of
Systems Engineering, Department of Transportation, Presented at 19th Technical
Conference of the International Air Transportation, Association, Washington, D.C.,
October 1972.
16. General Operating and Flight Rules, Part 91, Federal Aviation Regulations, Federal
Aviation Administration, Washington, D.C., February 1992.
17. National Airspace System Plan, Facilities, Equipment and Associated Development,
Federal Aviation Administration, Washington, D.C., 1989.
18. Parameters of Future ATC Systems Relating to Airport Capacity and Delay, Report
No. FAA-EM-78-8A, Federal Aviation Administration, Washington, D.C., 1978.
19. Planning the Metropolitan Airport System, Advisory Circular, AC 150/5070-5,
Federal Aviation Administration, Washington, D.C., May 1970.
20. “Relative Navigation Offers Alternatives to Differential GPS,. Aviation Week and
Space Technology, vol. 137, No. 22, New York, November 1992.
21. Report of Department of Transportation Air Traffic Control Advisory Committee, U.S.
Department of Transportation, Washington, D.C., December 1969.
22. Summary Report 1972, National Aviation System Planning Review Conference,
Federal Aviation Administration, Washington, D.C.
23. “The Advanced Air Traffic Management System Study,” R. L. Maxwell, Office
of Systems Engineering, Department of Transportation, Presented at the 19th
Technical Conference of the International Air Transportation Association, Washington,
D.C., October 1972.
24. Traffic Management System (TMS) Air Traffic Operation Requirements, Order No.
7032.9, Federal Aviation Administration, Washington, D.C., September 1992.
25. United States Aeronautical Information Publication, 12th ed., Federal Aviation
Administration, Washington, D.C., October 1992.
26. United States Standard for Terminal Instrument Procedures (TERPS), Order 8260.3B,
Federal Aviation Administration, Washington, D.C., May 1992.
131
This page intentionally left blank
CHAPTER
4
Airport
Planning
Studies
Introduction
The planning of an airport is such a complex process that the analysis
of one activity without regard to the effect on other activities will not
provide acceptable solutions. An airport encompasses a wide range
of activities which have different and often conflicting requirements.
Yet they are interdependent so that a single activity may limit the
capacity of the entire complex. In the past airport master plans were
developed on the basis of local aviation needs. In more recent times
these plans have been integrated into an airport system plan which
assessed not only the needs at a specific airport site but also the overall needs of the system of airports which service an area, region, state,
or country. If future airport planning efforts are to be successful, they
must be founded on guidelines established on the basis of comprehensive airport system and master plans.
The elements of a large airport are shown in Fig. 4-1. It is divided
into two major components, the airside and the landside. The aircraft
gates at the terminal buildings form the division between the two
components. Within the system, the characteristics of the vehicles,
both ground and air, have a large influence on planning. The passenger and shipper of goods are interested primarily in the overall doorto-door travel time and not just the duration of the air journey. For this
reason access to airports is an essential consideration in planning.
The problems resulting from the incorporation of airport operations into the web of metropolitan life are complex. In the early days
of air transport, airports were located at a distance from the city,
where inexpensive land and a limited number of obstructions permitted flexibility in airport operations. Because of the nature of aircraft and the infrequency of flights, noise was not a problem to the
133
Airport Planning
En route
airspace
Airport system
Terminal
airspace
Airfield surface
system
Air side
Runway
Holding
pad
Exit
taxiway
Taxiway
system
Apron-gate
area
Terminal
buildings
Land side
134
Vehicular
circulation
parking
Airport ground
access system
Aircraft
flow
Passenger
flow
FIGURE 4-1 Components of the airport system for a large airport.
community. In many cases the arrival and departure of passenger
and cargo planes was often a source of local pride. In addition, low
population density in the vicinity of the airport and light air traffic
prevented occasional accidents from alarming the community. In
spite of early lawsuits, the relationship between airport and community was relatively free of strife resulting from problems of nuisance
or hazard.
Airport operations have been increasingly hampered by obstructions resulting from industrial development related to the airport and
from industry attracted by adjacent inexpensive land and access to the
transportation afforded by the airfield and its associated highways.
Airport Planning Studies
While increasingly dense residential development has resulted from
this economic stimulation, one must not overlook the effects of the
unprecedented suburban spread during the post-World War II era,
resulting from the backlog of housing needs and a period of economic
prosperity.
Radical developments in the nature of air transport have produced new problems. The phenomenal growth of air traffic has
increased the probability of unfavorable community reaction, but
developments in the aircraft themselves have had the most profound
effect on airport community relations. The greater size and speed of
aircraft have resulted in increases in approach and runway requirements, while increases in the output of power plants have brought
increases in noise. Faced with these problems the airport must cope
with the problems of securing sufficient airspace for access to the airport, sufficient land for ground operations, and, at the same time,
adequate access to the metropolitan area.
Types of Studies
Many different types of studies are performed in airport planning.
These include studies related to facility planning, financial planning,
traffic and markets, economics, and the environment. However, each
of these studies can usually be classified as being performed at one of
three levels: the system planning level, the master planning level, or
the project planning level.
The Airport System Plan
An airport system plan is a representation of the aviation facilities
required to meet the immediate and future needs of a metropolitan
area, region, state, or country. The National Plan of Integrated Airport
Systems (NPIAS) [11] is an example of a system plan representing the
airport development needs of the United States. The Michigan Aviation System Plan [10] is an example of a system plan representing the
airport development needs of the state of Michigan, and the Southeast Michigan Regional Aviation System Plan [13] is a system plan
representing the airport development needs of a seven county region
comprising the Detroit Metropolitan area.
The system plan presents the recommendations for the general
location and characteristics of new airports and heliports and the
nature of expansion for existing ones to meet forecasts of aggregate
demand. It identifies the aviation role of existing and recommended
new airports and facilities. It includes the timing and estimated costs
of development and relates airport system planning to the policy and
objectives of the relevant jurisdiction. Its overall purpose is to determine the extent, type, nature, location, and timing of airport development needed to establish a viable, balanced, and integrated system of
135
136
Airport Planning
airports [1, 8]. It also provides the basis for detailed airport planning
such as that contained in the airport master plan.
The airport system plan provides both broad and specific policies, plans, and programs required to establish a viable and integrated
system of airports to meet the needs of the region. The objectives of
the system plan include
1. The orderly and timely development of a system of airports
adequate to meet present and future aviation needs and to
promote the desired pattern of regional growth relative to
industrial, employment, social, environmental, and recreational goals.
2. The development of aviation to meet its role in a balanced
and multimodal transportation system to foster the overall
goals of the area as reflected in the transportation system plan
and comprehensive development plan.
3. The protection and enhancement of the environment through
the location and expansion of aviation facilities in a manner
which avoids ecological and environmental impairment.
4. The provision of the framework within which specific airport
programs may be developed consistent with the short- and
long-range airport system requirements.
5. The implementation of land-use and airspace plans which
optimize these resources in an often constrained environment.
6. The development of long-range fiscal plans and the establishment of priorities for airport financing within the governmental budgeting process.
7. The establishment of the mechanism for the implementation
of the system plan through the normal political framework,
including the necessary coordination between governmental
agencies, the involvement of both public and private aviation
and nonaviation interests, and compatibility with the content, standards, and criteria of existing legislation.
The airport system planning process must be consistent with
state, regional, or national goals for transportation, land use, and the
environment. The elements in a typical airport system planning process [8] include the following:
1. Exploration of issues that impact aviation in the study area
2. Inventory of the current system
3. Identification of air transportation needs
4. Forecast of system demand
5. Consideration of alternative airport systems
Airport Planning Studies
6. Definition of airport roles and policy strategies
7. Recommendation of system changes, funding strategies, and
airport development
8. Preparation of an implementation plan
Although the process involves many varied elements, the final
product will result in the identification, preservation, and enhancement of the aviation system to meet current and future demand. The
ultimate result of the process will be the establishment of a viable,
balanced, and integrated system of airports.
Airport Site Selection
The emphasis in airport planning is normally on the expansion and
improvement of existing airports. However if an existing airport
cannot be expanded to meet the future demand or the need for a
new airport is identified in an airport system plan, a process to
select a new airport site may be required. The scope of the site selection process will vary with size, complexity, and role of the new
airport, but there are basically three steps—identification, screening, and selection.
Identification—criteria is developed that will be used to evaluate
different sites and determine if a site can function as an airport and
meets the needs of the community and users. One criterion will be
to identify the land area and basic facility requirements for the new
airport. Part of this analysis will be a definition of airport roles if
more than two airports serve the region. Other criteria might be
that sites are within a certain radius or distance from the existing
airport or community, or that sites should be relatively flat. Several
potential sites that meet the criteria are identified.
Screening—once sites are identified, a screening process can be
applied to each site. An evaluation of all potential sites that meet
the initial criteria should be conducted, screening out those with
the most obvious shortcomings. Screening factors might include
topography, natural and man-made obstructions, airspace, access,
environmental impacts, and development costs. If any sites are
eliminated from further consideration, thorough documentation
of the reasons for that decision is recommended. The remaining
potential sites should then undergo a detailed comparison using
comprehensive evaluation criteria. While the criteria will vary, the
following is typically considered:
Operational capability—airspace considerations, obstructions,
weather
Capacity potential—available land, suitability for construction,
weather
137
138
Airport Planning
Ground access—distance from the demand for aviation services,
regional highway infrastructure, available public transportation modes
Development costs—terrain, land costs, land values, soil conditions, availability of utilities
Environmental consequences—aircraft noise, air quality, groundwater runoff, impact on flora and fauna, existence of endangered species or cultural artifacts, historical features, changes
in local land use, relocation of families and businesses, changes
in socioeconomic characteristics
Compatibility with area-wide planning—impact on land use, effect
on comprehensive land-use plans and transportation plans at
the local and regional levels
Selection—the final step is selecting and recommending a preferred
site. While a weighting of the evaluation criteria and weighted
ratings or ranking of the alternative sites is often used in selecting
a site, caution must be used in applying this technique since it
introduces an element of sensitivity into the analysis. The process
should focus on providing decision makers with information on the
various sites in a manner that is understandable and unbiased.
The Airport Master Plan
An airport master plan is a concept of the ultimate development of a
specific airport. The term development includes the entire airport
area, both for aviation and nonaviation uses, and the use of land adjacent to the airport [1, 4, 9]. It presents the development concept
graphically and contains the data and rationale upon which the plan
is based. Figure 4-2 shows a simple flowchart of the steps for preparing an airport master plan. Master plans are prepared to support
expansion and modernization of existing airports and guide the
development of new airports.
The overall objective of the airport master plan is to provide
guidelines for future development which will satisfy aviation demand
in a financially feasible manner and be compatible with the environment, community development, and other modes of transportation.
More specifically it is a guide for
1. Developing the physical facilities of an airport
2. Developing land on and adjacent to the airport
3. Determining the environmental effects of airport construction and operations
4. Establishing access requirements
5. Establishing the technical, economic and financial feasibility
of proposed developments through a thorough investigation
of alternative concepts
Airport Planning Studies
Collect and analyse data
Forecast traffic demand
Capacity analysis of
airport system
Operating
policies
Yes
New airport
Space standards and
level of service
No
Select new airport sites
Evaluate new sites
Select best site
Size airport facilities
Prepare alternative layouts
Evaluate layouts
Select best layout
AIRPORT MASTER PLAN
FIGURE 4-2
Flowchart for preparing an airport master plan.
6. Establishing a schedule of priorities and phasing for the
improvements proposed in the plan
7. Establishing an achievable financial plan to support the
implementation schedule
8. Establishing a continuing planning process which will monitor conditions and adjust plan recommendations as circumstances warrant
Guidelines for completing an airport master plan are described
by ICAO [4] and in the United States by the FAA [1]. A master plan
report is typically organized as follows:
Master plan vision, goals, and objectives—establishes the vision and
overarching goals for the master plan as well as objectives that
139
140
Airport Planning
will guide the planning process and help ensure that the goals are
achieved and the vision is realized.
Inventory of existing conditions—provides an overview of the airport’s history, role in the region and nation, growth and development over time, description of its physical assets (airfield and
airspace, terminal, ground access, and support facilities), and key
industry trends.
Forecast of aviation demand—future levels of aircraft operations,
number of passengers, and volume of cargo are forecasted for
short, intermediate, and long-range time periods. Typically forecasts are made for 5, 10, and 20 years on both annual as well daily
and busiest hours of the day.
Demand/capacity analysis and facility requirements—compares the
future demand with the existing capacity of each airport component and identifies the facility requirements necessary to accommodate the demand.
Alternatives development—identifies, refines, and evaluates a range
of alternatives for accommodating facility requirements. If the
existing site cannot accommodate the anticipated growth, a selection process to find a new site may be necessary.
Preferred development plan—identifies, describes, and defines the
alternative that best achieves the master plan goals and objectives.
Figure 4-3 illustrates the development plan for the Chicago O’Hare
International Airport.
Implementation plan—provides a comprehensive plan for the implementation of the preferred development plan, including the definition of projects, construction sequence and timeline, cost estimates,
and financial plan.
Environmental overview—provides an overview of the anticipated
environmental impacts associated with the preferred development plan in order to understand the severity and to help expedite subsequent environmental processing at the project specific
stage.
Airport plans package—documents that show the existing as well
as planned modifications are prepared and the more notable
is the airport layout plan (ALP). It comprises drawings that
include the airfield’s physical facilities, obstruction clearance
and runway approach profiles, land-use plans, terminal area and
ground access plans, and a property map. Specific guidelines
for the airport layout plan in the United States are identified
by FAA [1].
Stakeholder and public involvement—documents the coordination efforts that occur among the stakeholders throughout the
study.
Airport Planning Studies
FIGURE 4-3
Development plan for Chicago O’Hare International Airport.
The Airport Project Plan
A project plan focuses on a specific element of the airport master plan
which is to be implemented in the short term and may include such
items as the addition of a new runway, the modification of existing of
runways, the provision of taxiways or taxiway exits, the addition of
gates, the addition to or the renovation of terminal building facilities,
or the modification of ground access facilities.
141
142
Airport Planning
The overall objective of the airport project plan is to provide the
specific details of the development which will satisfy immediate aviation needs and be consistent with the objectives and constraints
identified in the airport master plan. More specifically it is a detailed
plan for
1. Developing the specific physical facilities at an airport
including the architectural and engineering design for these
facilities
2. Determining the environmental effects of this development
through the construction and operational phases
3. Determining the detailed costs and financial planning for the
development
4. Establishing a schedule for the construction and phasing of
the specific items of development in the plan
Land-Use Planning
A land-use plan for property within the airport boundary and in
areas adjacent to the airport is an essential part of an airport master
plan. The land-use plan on and off the airport is an integral part of an
area wide comprehensive planning program, and therefore it must be
coordinated with the objectives, policies, and programs for the area
which the airport is to serve. Incompatibility of the airport with its
neighbors stems primarily from the objections of people to aircraft
noise. A land-use plan must therefore project the extent of aircraft noise
that will be generated by airport operations in the future. Contours of
equal intensity of noise can be drawn and overlaid on a land-use map
and from these contours an estimate can be made of the compatibility
of existing land use with airport operations. If the land outside the
airport is underdeveloped, the contours are the basis for establishing
comprehensive land-use zoning requirements.
Although zoning is used as a method for controlling land use
adjacent to an airport, it is not effective in areas which are already
built-up because it is usually not retroactive. Furthermore jurisdictions having zoning powers may not take effective zoning action.
Aircraft operations into and out of the airport may be made unnecessarily complex to minimize noise encroachment on incompatible
land uses. Despite these shortcomings the planner should utilize
zoning as a vehicle to achieve compatibility wherever this approach
is feasible.
Airports become involved in two types of zoning. One type is
height and hazard zoning, which is mainly to protect the approaches
to the airport from obstructions. The other type is land-use zoning.
The extent of land use in the airport depends a great deal on the
amount of acreage available. Land uses can be classified as either
Airport Planning Studies
closely related to aviation or remotely related to aviation. Those
closely related to aviation use include the runways, taxiways,
aprons, terminal buildings, parking, and maintenance facilities.
Nonaviation uses include space for recreational, industrial, and
commercial activities. When considering commercial or industrial
activities, care should be taken to ensure that they will not interfere
with aircraft operations, communications equipment, and aids to
navigation on the ground. Recreational facilities such as golf courses
may be suitable within the immediate proximity of the airport
boundary or certain agricultural uses are also appropriate as long as
they do not attract birds. When there is acreage within the airport
boundary in excess of aviation needs, it is sound fiscal planning to
provide the greatest financial return from leases of the excess property. Thus the land-use plan within the airport is a very effective
tool in helping airport management make decisions concerning
requests for land use by various interests and often airports delineate areas on the airport property for the development of industrial
parks.
The principal objective of the land-use plan for areas outside the
airport boundary is to minimize the disturbing effects of noise. As
stated earlier the delineation of noise contours is the most promising
approach for establishing noise-sensitive areas. The contours define
the areas which are or are not suitable for residential use or other use
and, likewise, those which are suitable for light industrial, commercial, or recreational activity. Although the responsibility for developing land uses adjacent to the airport lies with the governing bodies of
adjacent communities, the land-use plan provided by the airport
authority will greatly influence and assist the governing bodies in
their task of establishing comprehensive land-use zoning.
Environmental Impact Assessment
Environmental factors must be considered carefully in the development of a new airport or the expansion of an existing one. In the
United States, this is a requirement of the Airport and Airway
Improvement Act of 1982 and the Environmental Policy Act of 1969.
Studies of the impact of the construction and operation of a new airport or the expansion of an existing one upon acceptable levels of air
and water quality, noise levels, ecological processes, and demographic
development of the region must be conducted to determine how the
airport requirements can best be met with minimal adverse environmental and social consequences.
Aircraft noise is the severest environmental problem to be considered in the development of airport facilities. Much has been done to
quiet engines and modify flight procedures, resulting in substantial
reductions in noise. Another effective means for reducing noise is
through proper planning of land use for areas adjacent to the airport.
For an existing airport this may be difficult as the land may have
143
144
Airport Planning
already been built up. Every effort should be made to orient air traffic
away from noise-sensitive land development.
Other important environmental factors include air and water
pollution, industrial wastes and domestic sewage originating at the
airport, and the disturbance of natural environmental values. In
regard to air pollution, the federal government and industry have
worked jointly toward alleviating the problem, and there is a reason
to believe that it will probably be eliminated in the near future as an
environmental factor. An airport can be a major contributor to water
pollution if suitable treatment facilities for airport wastes are not
provided. Chemicals used to deice aircraft are a major source of
potential ground water pollution and provisions need to be made to
safely dispose of this waste product. The environmental study must
include a statement detailing the methods for handling sources of
water pollution.
The construction of a new airport or the expansion of an existing
one may have major impacts on the natural environment. This is
particularly true for large developments where streams and major
drainage courses may be changed, the habitats of wildlife may be
disrupted, and wilderness and recreational areas may be reshaped.
The environmental study should indicate how these disruptions
might be alleviated.
In the preparation of an environmental study, or an environmental impact statement, the findings must include the following
items [12]:
1. The environmental impact of the proposed development
2. Any adverse environmental effects which cannot be avoided
should the development be implemented
3. Alternatives to the proposed development
4. The relationship between local short-term uses of the environment and the maintenance and enhancement of long-term
productivity
5. Any irreversible environmental and irretrievable commitments of resources which would be involved in the proposed
development should it be implemented
6. Growth inducing impact
7. Mitigation measures to minimize impact
In the application of these guidelines attention must be directed
to the following questions. Will the proposed development
1. Cause controversy
2. Noticeably affect the ambient noise level for a significant
number of people
Airport Planning Studies
3. Displace a significant number of people
4. Have a significant aesthetic or visual effect
5. Divide or disrupt an established community or divide existing uses
6. Have any effect on areas of unique interest or scenic beauty
7. Destroy or derogate important recreational areas
8. Substantially alter the pattern of behavior for a species
9. Interfere with important wildlife breeding, nesting, or feeding grounds
10. Significantly increase air or water pollution
11. Adversely affect the water table of an area
12. Cause excessive congestion on existing ground transportation facilities
13. Adversely affect the land-use plan for the region
The preparation of an environmental impact statement based
upon an environmental assessment study is an extremely important
part of the airport planning process. The statement should clearly
identify the problems that will affect environmental quality and the
proposed actions to alleviate them. Unless the statement is sufficiently
comprehensive, the entire airport development may be in jeopardy.
Economic and Financial Feasibility
The economic and financial feasibility of alternative plans for a new
airport or expansion of an existing site must be clearly demonstrated
by the planner. Even if the selected alternative is shown to be economically feasible, then also it is necessary to show that the plan will
generate sufficient revenues to cover annual costs of capital investment, administration, operations, and maintenance. This must be
determined for each stage or phase of development detailed in the
airport master plan.
An evaluation of economic feasibility requires an analysis of benefits and costs. A comparison of benefits and costs of potential capital
investment programs indicates the desirability of a project from an
economic point of view. The economic criterion used in evaluating an
aviation investment is the total cost of facilities, including quantifiable social costs, compared with the value of the increased effectiveness measured in terms of total benefits. The costs include capital
investment, administration, operation, maintenance, and any other
costs that can be quantified. The benefits include a reduction in aircraft and passenger delays, improved operating efficiency, and other
benefits. The costs and benefits are usually determined on an annual
basis.
145
146
Airport Planning
There are a number of techniques for comparing benefits with
costs. Most of them consider the time value of money based on an
appropriate discount rate which reflects the opportunity cost of capital.
The discount rate is a value by which a unit of money received in the
future is multiplied to obtain its present value or present worth. In
other words a cost incurred in 2010 has a different economic value
from that of the same item incurred in 2015.
If the time value of money is not considered, the ratio of benefits
to costs is made for each year by merely dividing the benefits in a
particular year by the cost of the project in that year. A project is considered economically feasible when the ratio of the benefits to costs is
greater than unity, that is, the benefits exceed the costs. The larger the
ratio, the more attractive is the project from an economic standpoint.
A ratio can also be obtained by comparing the present value of benefits with the present value of costs. This approach recognizes the time
value of money. Another approach is to plot the net present value
(NPV) for each year against time. The net present value is defined as
the present value of benefits minus the present value of costs.
The financing of capital improvements for airports is discussed in
Chap. 13. In the early years of airport development, substantial capital improvement programs were financed at the local level by sale of
general obligation bonds backed by the taxing power of the community. As air transportation became mature and the requirements of the
community for capital spending programs increased, airports began
to utilize revenue bonds as a source of financing. A financial feasibility study is therefore an analysis to determine if bonds are marketable
at reasonable interest rates. It also includes the feasibility of other
forms of financing. The analysis requires a thorough evaluation of the
revenues to be developed by a proposed improvement and the corresponding costs. Usually this is done in a traffic and earnings study
performed over the planning horizon. In such a study, the forecast of
demand is utilized and rates and charges established for the various
revenue categories. This results in annual revenue projections. To
make revenue bonds attractive to buyers a typical airport revenue
bond should show an expected coverage by net revenues (gross revenues minus costs) of at least 1.25 times the debt service requirements.
If the analysis indicates that the revenues will be insufficient, revisions in the scheduling or scope of the proposed development may
have to be made or the rates and charges to the users of the airport
may require adjustment.
Continuing Planning Process
A continuous airport planning process is necessary in order to respond
to the needs of air transportation in a changing environment [8].
Changes in aviation demand, community policies, new technology,
Airport Planning Studies
financial constraints, and other factors can alter the need for and the
timing of facility improvements. Current data must be continually collected and assessed relative to airport needs, operations and utilization, environmental impact, and financial capabilities. The staging of
airport improvements assists in the reevaluation of continuing needs
at the points in time when implementation decisions are required.
In the airport planning process, the overall objective of establishing and maintaining a continuous process is to ensure that the airport
system plan and airport master plan remain responsive to public
needs. As a result, the airport system plan and airport master plan
should be formally reviewed and updated at least every 5 years. Specific objectives associated with the continuous airport planning process include [8]
1. Surveillance, maintenance, inventory, and update of the basic
data such as aviation activity and socioeconomic and environmental factors relating to the existing airport system and
master plan
2. Review and validation of data affecting the airport system
and master plan
3. Reappraisal of the airport system and master plan in view of
changing conditions
4. Modification of the airport system and master plan to retain
its viability
5. Development of a continuous mechanism for ensuring the
interchange of information between the system planning and
master planning processes
6. Provision of a means for receiving and considering public
comment in order to maintain and ensure the public awareness of the role airports play in the transportation system of
an area
7. Redefinition of air transportation goals and policies
8. Integration of airport system planning into a multimodal
planning process
9. Analysis of special issues
10. Publication of interim reports and formal plan updates
References
1. Airport Master Plans, Advisory Circular, AC 150/5070-6B, Federal Aviation
Administration, Washington, D.C., July 2005.
2. Airport Planning and Development Handbook—A Global Survey, Paul Stephen
Dempsey, McGraw-Hill, New York, N.Y., 2000.
3. Airport Planning and Management, 5th ed., Alexander T. Wells and Seth B. Young,
McGraw-Hill, New York, N.Y., 2004.
147
148
Airport Planning
4. Airport Planning Manual, Part 1, Master Planning, 2d ed., International Civil
Aviation Organization, Montreal, Canada, 1987.
5. Airport Systems—Planning, Design and Management, Richard de Neufville and
Amedeo Odoni, McGraw-Hill, New York, N.Y., 2003.
6. Airport System Capacity, Strategic Choices, Special Report, No. 226,
Transportation Research Board, Washington, D.C., 1990.
7. Airport Systems Planning, R. DeNeufville, The MIT Press, Cambridge, Mass.,
1976.
8. The Airport System Planning Process, Advisory Circular, AC 150/5070-7, Federal
Aviation Administration, Washington, D.C., November 2004.
9. Guide for the Planning of Small Airports, Roads and Transportation Association
of Canada, Ottawa, Canada, 1980.
10. Michigan Airport System Plan, MASP 2000, Michigan Department of
Transportation, Lansing, Mich., January 2000.
11. National Plan of Integrated Airport Systems (NPIAS)2007-2011, Federal Aviation
Administration, U.S. Department of Transportation, Washington, D.C.,
September 2006.
12. Policies and Procedures for Considering Environmental Impacts, Federal Aviation
Administration, Washington, D.C., December 1986.
13. Southeast Michigan Regional Aviation System Plan, Technical Report, Southeast
Michigan Council of Governments, Detroit, Mich., April 1992.
14. Strategic Airport Planning, Robert E. Caves and Geoffrey D. Gosling, Elsevier
Science Limited, Oxford, U.K., 1999.
CHAPTER
5
Forecasting for
Airport Planning
Introduction
Plans for the development of the various components of the airport
system depend to a large extent on the activity levels which are forecast for the future. Since the purpose of an airport is to process aircraft, passengers, freight, and ground transport vehicles in an efficient
and safe manner, airport performance is judged on the basis of how
well the demand placed upon the facilities within the system is handled. To adequately assess the causes of performance breakdowns in
existing airport systems and to plan facilities to meet future needs, it
is essential to predict the level and distribution of demand on the
various components of the airport system. Without a reliable knowledge of the nature and expected variation in the loads placed upon a
component, it is impossible to realistically assess the physical and
operational requirements of such a component. For example, a forecast to project the mix of aircraft and the types of aviation activity at
an airport site is necessary to identify the critical aircraft which dictates the elements of geometric and structural design, the type and
extent of physical facilities, the navigational aid requirements, and
any special or unique facility needs at the airport [15, 17].
An understanding of future demand patterns allows the planner
to assess future airport performance in light of existing and improved
facilities, to evaluate the impact of various quality of service options
on the airlines, travelers, shippers, and community, to recommend
development programs consistent with the overall objectives and
policies of the airport operator, to estimate the costs associated with
these facility plans, and to project the sources and level of revenues to
support the capital improvement program.
It is essential in the planning and design of an airport to have
realistic estimates of the future demand to which airports are likely to
be subjected. This is a basic requirement in developing either an
149
150
Airport Planning
airport master plan or an airport system plan. These estimates determine the future needs for which the physical facilities are designed. A
financial plan to achieve the recommended staged development
along with required land-use zoning usually accompanies the plan. It
should be apparent that an airport is designed for a projected level
and pattern of demand and changes in the magnitude or characteristics of this demand may require facility modifications or operational
measures to meet changing needs. Facility planning is necessary to
provide adequate levels of service to airport users.
The development of accurate forecasts requires a considerable
expense of time and other resources because of the complex methodologies which must be used and the extensive data acquisition that is often
required. The usual justification for a demand forecast in an aviation
plan is that the expected level of uncertainty associated with the estimation of essential variables will be reduced, thereby reducing the probability of errors in the planning process and enhancing the decision-making
process. The implication, of course, is that the benefits gained due to a
better knowledge of the magnitude and fluctuation in demand variables
will outweigh the costs incurred in performing the forecast.
To assess the characteristics of future demand, the development
of reliable predictions of airport activity is necessary. There are numerous factors that will affect the demand and planners who are preparing forecasts of demand or updating existing forecasts should consider
local and regional socioeconomic data and characteristics, demographics, geographic attributes, and external factors such as fuel costs
and quality of service parameters. Political developments, including
rising international tensions, changes in security, airline delays and
congestion, and travel attitudes, will impact demand. Actions taken
by local airport authorities, such as changes in user charges, can also
stimulate or hinder the demand and investment decisions made as
the result of the planning process itself can also produce change by
removing physical constraints to growth [2].
Over the years, certain techniques have evolved which enable airport planners and designers to forecast future demand. The principal
items for which estimates are usually needed include
• The volume and peaking characteristics of passengers, aircraft, vehicles, and cargo
• The number and types of aircraft needed to serve the above
traffic
• The number of based general aviation aircraft and the number of movements generated
• The performance and operating characteristics of ground
access systems
Using forecasting techniques, estimates of these parameters and a
determination of the peak period volumes of passengers and aircraft
Forecasting for Airport Planning
movements can be made. From these estimates concepts for the layout and sizing of terminal buildings, runways, taxiways, apron areas,
and ground access facilities may be examined.
Forecasting demand in an industry as dynamic as aviation is an
extremely difficult matter, and if it could be avoided it undoubtedly
would. Nonetheless estimates of traffic must be made as a prelude
to the planning and design of facilities. It is very important to remember that forecasting is not a precise science and that considerable subjective judgment must be applied to any analysis no matter how
sophisticated the mathematical techniques involved. By anticipating
and planning for variations in predicted demand, the airport designer
can correct projected service deficiencies before serious deficiencies
in the system occur.
Levels of Forecasting
Demand estimates are prepared for a variety of reasons. Broad
large-scale aggregated forecasts are made by aircraft and equipment
manufacturers, aviation trade organizations, governmental agencies,
and others to determine estimates of the market requirements for
aviation equipment, trends in travel, personnel needs, air traffic control requirements, and other factors. Similarly, forecasts are made on
a smaller scale to examine these needs in particular regions of an area
and at specific airports.
In economics, forecasting is done on two levels, aggregate forecasting and disaggregate forecasting, and the same holds true in aviation.
From the inception of the planning process for an airport consideration is given at both levels. In airport planning, the designer must
view the entire airport system as well as the airport under immediate
consideration. Aggregate forecasts are forecasts of the total aviation
activity in a large region such as a country, state, or metropolitan area.
Typical aggregate forecasts are made for such variables as the total
revenue passenger-miles, total enplaned passengers, and the number
of aircraft operations, aircraft in the fleet, and licensed pilots in the
country. Disaggregate forecasts deal with the activity at individual
airports or on individual routes. Disaggregate forecasts for airport
planning determine such variables as the number of originations, passenger origin-destination traffic, the number of enplaned passengers,
and the number of aircraft operations by air carrier and general aviation aircraft at an airport. Separate forecasts are usually made, depending on the need in a particular study, for cargo movements, commuter
service, and ground access traffic. These forecasts are normally prepared to indicate annual levels of activity and are then disaggregated
for airport planning purposes to provide forecasts of the peaking
characteristics of traffic during the busy hours of the day, days of the
week, and months of the year. As appropriate to the requirements of
an airport planning study, forecasts of such quantities as the number
151
152
Airport Planning
of general aviation aircraft based at an individual airport and the number of general aviation and military operations are also prepared.
In aggregate forecasting, the entire system of airports is examined relative to the geographic, economic, industrial, and growth
characteristics of a region to determine the location and nature of
airport needs in a region. The disaggregate forecast then examines
the expected demand at local airports and identifies the necessary
development of the airside, landside, and terminal facilities to provide adequate levels of service. Within the two levels of forecasting
there are certain techniques which enable the planner to project such
parameters as annual, daily, and hourly aircraft operations, passenger enplanements, cargo, and general aviation activity. In disaggregate forecasting, there are many significant variables. The forecast
of each variable is quite important because it ultimately determines
the size requirements of the facilities which will be necessary to
accommodate demand. Often, the forecasts of the different variables
are linked by a series of steps, that is, originating passengers are
forecast first, this then becomes a component in the forecast of
enplaned passengers, which leads to a forecast of annual operations,
and so on.
The type of forecast and the level of effort depend on the purpose
for which the forecast is being used. Forecasts are typically prepared
for short-, medium-, and long-term periods. Short-term forecasts, up
to 5 years, are used to justify near-term development and support
operational planning and incremental improvements or expansion of
facilities. Medium-term forecasts, a 6- to 10-year time frame, and
long-term forecasts of 10 to 20 years are used to plan major capital
improvements, such as land acquisition, new runways and taxiways,
extensions of a runway, a new terminal, and ground access infrastructure. Forecasts beyond 20 years are used to assess the need for additional airports or other regional aviation facilities [1].
Forecasting Methods
There are several forecasting methods or techniques available to airport planners ranging from subjective judgment to sophisticated
mathematical modeling. The selection of the particular methodology
is a function of the use of the forecast, the availability of a database, the
complexity and sophistication of the techniques, the resources available, the time frame in which the forecast is required and is to be used,
and the degree of precision desirable. There are four major methods:
• Time series method
• Market share method
• Econometric modeling
• Simulation modeling
Forecasting for Airport Planning
Time series analysis essentially involves extrapolating or projecting existing historical activity data into the future. Market share forecasting is a simple top-down approach, where current activity at an
airport is calculated as a share of some other more aggregate measure
for which a forecast has been made (typically a regional, state, or
national forecast of aviation activity). Econometric modeling is a
multistep process in which a casual relationship is established
between a dependent variable (the item to be forecast) and a set of
independent variables that influence the demand for air travel. Once
the relationship is established, forecasts of independent variables are
input to determine a forecast of the dependent variable. These techniques can also be referred to as a bottom-up forecast. Simulation
models are often used when one needs very detailed estimates of aircraft, passengers, or vehicles. These models impose precise rules that
govern how passengers, aircraft, or vehicles are routed, and then
aggregates the results so that planners can assess the needs of the
network or a component of the airport to handle the estimated
demand. Typically the outputs from the other forecasting methods
are used as inputs to simulation models. Forecasts from simulation
models represent snapshots of how a given amount of traffic flows
across a network or through an airport, rather than a monthly or
annual estimate of total traffic.
An important element which should be utilized in any forecasting technique is the use of professional judgment. A forecast prepared
through the use of mathematical relationships must ultimately withstand the test of rationality. Frequently a group of professionals
knowledgeable about aviation and the factors influencing aviation
trends are assembled to examine forecasts from several different
sources, and composite forecasts are prepared in accordance with the
information in these sources and the collective judgment of the group.
In some cases, judgment becomes the principal approach used with
or without an evaluation of economic and other factors that are
believed to affect aviation activity. A common approach being utilized more often today for preparing forecasts by judgment is known
as the Delphi method. In this method a panel of experts on a particular subject matter is asked to rate or otherwise prioritize a series of
questions or projections through a survey technique. The results of
the survey are then distributed to the members of the panel and an
opportunity is provided for each member to reevaluate the original
rating based upon the collective ratings of the group. The reevaluation process is often sent through several iterations in order to arrive
at a better result. In the Delphi method, the results of the technique do
not have to represent a consensus of the panel and, in fact, it is often
quite useful to have a forecast which indicates the spread of the panel
in reaching conclusions on a particular issue.
The preparation of judgmental forecasts which reflect the collective wisdom of a broad range of professionals has proven to be very
153
154
Airport Planning
successful in many instances principally due to the large number of
factors which may be considered in such a process. Though there is
often a lack of mathematical sophistication in the process, the knowledge and consideration of the many diverse factors influencing aviation forecasts usually improves the results. The disadvantages of this
forecasting technique include the absence of statistical measures on
which to base the results and the inability, except in the most obvious
cases, to gain a significant consensus relative to the expected performance of the explanatory factors in the future.
Time Series Method
Time series analysis or extrapolation is based upon an examination of
the historical pattern of activity and assumes that those factors which
determine the variation of traffic in the past will continue to exhibit
similar relationships in the future. This technique utilizes times series
type data and seeks to analyze the growth and growth rates associated with a particular aviation activity. In practice, trends appear to
develop in situations in which the growth rate of a variable is stable
in either absolute or percentage terms, there is a gradual increase or
decrease in growth rate, or there is a clear indication of market saturation trend over time [11]. Statistical techniques are used to assist in
defining the reliability and the expected range in the extrapolated
trend. The analysis of the pattern of demand generally requires that
upper and lower bounds be placed upon the forecast and statistics
are used to define the confidence levels within which specific projections may be expected to be valid. From the variation in the trends
and the upper and lower bounds placed on the forecast a preferred
forecast is usually developed. Quite often smoothing techniques are
incorporated into the forecast to eliminate short run, or seasonal, fluctuations in a pattern of activity which otherwise demonstrates a trend
or cyclical pattern in the long run [16].
An illustration of the application of a trend line analysis to forecast
annual enplanements at an airport is shown in Example Problem 5-1.
Example Problem 5-1 The historical data shown in Table 5-1 have been collected
for the annual passenger enplanements in a region and one of the commercial
service airports in this region. It is necessary to prepare a forecast of the annual
passenger enplanements at the study airport in the design years 2010 and 2015
using a trend line analysis.
In applying the trend line analysis to these data, a forecast technique of the
annual enplanements at the study airport will be made by forecasting the historical trend to the design years. A plot of the trend in the annual passengers
enplaned at the study airport is given in Fig. 5-1.
By extrapolating the trend into the future, an estimate of the annual enplaned
passengers at the study airport in 2010 is found to be 2,100,000 passengers and
in the year 2015 is found to be 2,900,000 passengers.
Forecasting for Airport Planning
Annual Enplanements
Year
Regional
Airport
Area Population
1998
13,060,000
468,900
250,000
1999
14,733,000
514,300
260,000
2000
16,937,000
637,600
270,000
2001
21,896,000
758,200
280,000
2002
24,350,000
935,200
290,000
2003
28,004,000
995,500
300,000
2004
31,658,000
1,139,700
310,000
2005
37,226,000
1,360,700
320,000
2006
40,753,000
1,488,900
330,000
2007
44,018,000
1,650,600
340,000
TABLE 5-1 Enplanement Data for Airport Demand Forecast for Use in
Example Problems 5-1 through 5-3
3600
3400
Forecast
Historical Data
Annual Enplanements (Thousands)
3200
3000
2900
2800
2600
2400
2200
2100
2000
1800
1600
1400
1200
1000
800
600
400
2000
2005
2010
Year
FIGURE 5-1 Trend line forecast of annual enplanements for Example
Problem 5-1.
2015
155
156
Airport Planning
The inability of time series techniques to show a causal relationship between the dependent and independent variables is a serious
disadvantage. This is particularly true because, in the absence of such
relationships, the degree of uncertainty in such forecasts increases
with time. However, the time series method is useful for short-term
forecasts in which the response to changes in those factors which
stimulate the dependent variables is usually less dynamic. In those
cases where cyclic variations may be expected to occur, time series
methods may also be quite beneficial.
Market Share Method
Forecasting techniques which are utilized to proportion a large-scale
aviation activity down to a local level are called market share, ratio,
or top-down models. Inherent to the use of such a method is the demonstration that the proportion of the large-scale activity which can be
assigned to the local level is a regular and predictable quantity. This
method has been the dominant technique for aviation demand forecasting at the local level and its most common use is in the determination of the share of total national traffic activity which will be captured
by a particular region, traffic hub, or airport. Historical data are examined to determine the ratio of local airport traffic to total national
traffic and the trends are ascertained. From exogenous sources the
projected levels of national activity are determined and these values
are then proportioned to the local airport based upon the observed
and projected trends. The ratio method is most commonly used in the
development of microforecasts for regional airport system plans or
for airport master plans.
These methods are particularly useful in applications in which it
can be demonstrated that the market share is a regular, stable, or predictable parameter. For example, the number of annual enplaned
passengers at major air traffic hubs has been shown to be a consistent
and relatively stable factor and, therefore, this method is often used
to predict this parameter.
Quite often the application of the market share technique is a twostep process in which a ratio is applied to disaggregate activity forecasts from a national to a regional level and then another ratio is applied
to apportion the regional share among the airports in the region.
The most compelling advantage of the market share method is its
dependence on existing data sources which minimizes forecasting
cost. However, its principal disadvantages lie in its dependence on
the stability and predictability of the ratios from which the forecasts
are made and the uncertainty which may surround market shares in
specific applications. Several forecasts may be required under a differing set of assumptions which are deemed appropriate to the determination of market shares. An illustration of the application of a market
share analysis is given in Example Problem 5-2.
Airport Percentage of
Regional Annual
Enplanements
Forecasting for Airport Planning
4.0
3.8
3.6
3.4
1998
2000
2002
Year
2004
2006
FIGURE 5-2 Trend line of airport percentage of regional annual enplanements
for Example Problem 5-2.
Airport Percentage of
Regional Annual
Enplanements
Example Problem 5-2 The historical data shown in Table 5-1 could also be used
to prepare a forecast of the annual passenger enplanements at the study airport
in the design years 2010 and 2015 using a market share method.
In applying the market share method to these data, a top-down forecast technique will be used. The implicit assumption in such a technique is that the same
relationship between regional annual enplanements and the annual enplanements at the study airport will be maintained in the future. To prepare such a
forecast, a projection of the percentage of the regional annual enplanements captured at the study airport is performed and then a forecast is made of the regional
annual enplanements. The study airport forecast percentage is applied to the
regional forecast to arrive at the forecast of the study airport annual enplanements in the design years. A plot of the trend in the percentage of regional annual
passengers enplaned at the study airport is given in Fig. 5-2.
Because the variations shown in Fig. 5-2 often make it difficult to determine
if trends may exist, a smoothing function is often applied to the data to assist in
identifying trends which may not be obvious. In this case, a smoothing of the
data was obtained by computing a running 3-year average of the data points. As
is shown in Fig. 5-3, this tends to smooth out the variations in the original data
and more readily identifies trends in these data.
Though it may not be apparent in the original plot, the smoothing mechanism
does indicate a very slight upward trend in the percentage of regional annual passengers captured by the study airport. This trend is shown by the dashed line in
Fig. 5-3. This trend line, when projected to the design years, indicates a forecast of
4.0
Historical Data
3.8
Forecast
3.75
3.70
3.6
3.4
2000
2005
2010
2015
Year
FIGURE 5-3 Trend line forecast of airport percentage of regional annual
enplanements by applying smoothing function to trend data for Example
Problem 5-2.
157
Airport Planning
3.70 percent in the year 2010 and 3.75 percent in the year 2015 as the proportion of
regional annual enplanements forecast to be captured by the study airport.
To complete the forecast by the market share method, a determination of the
regional annual enplanements must be made. This is done by extrapolating the
trend in regional annual enplanements as shown in Fig. 5-4. This extrapolation
indicates regional annual enplanements in the year 2010 of 52,500,000 and in the
year 2015 of 63,500,000.
Therefore, the forecast for the annual enplanements at the study airport
becomes 0.0370 × 52,500,000 = 1,942,500 passengers in the year 2010 and 0.0375 ×
63,500,000 = 2,381,250 passengers in the year 2015.
Econometric Modeling
The most sophisticated and complex technique in airport demand
forecasting is the use of econometric models. Trend extrapolation
methods do not explicitly examine the underlying relationships
between the projected activity descriptor and the many variables
which affect its change. There are a wide range of economic, social,
market, and operational factors which affect aviation. Therefore, to
properly assess the impact of predicted changes in the other sectors
of society upon aviation demand and to investigate the effect of alternative assumptions on aviation, it is often desirable to use mathematical techniques to study the correlations between dependent and
independent variables. Econometric models which relate measures of
aviation activity to economic and social factors are extremely valuable techniques in forecasting the future.
80
Historical Data
Regional Annual Enplanements (Millions)
158
70
Forecast
63.5
60
52.2
50
40
30
20
10
2000
2005
Year
2010
2015
FIGURE 5-4 Trend line forecast of regional annual enplanements for Example
Problem 5-2.
Forecasting for Airport Planning
There are a great variety of techniques which are used in econometric modeling for airport planning. Classical trip generation and
gravity models are quite common in forecasting passenger and aircraft traffic. Simple and multiple regression analysis techniques, both
linear and nonlinear, are often applied to a great variety of forecasting
problems to ascertain the relationships between the dependent variables and such explanatory variables as economic and population
growth, market factors, travel impedance, and intermodal competition. The form of the equations used in multiple linear regression
analysis is given in Eq. (5-1).
Yest = a0 + a1 X1 + a2 X2 + a3 X3 + ··· + anXn
(5-1)
Yest = dependent variable or variable which is being
forecast
X1, X2, X3,…, Xn = dependent variables or variables being used to
explain the variation in the dependent variable
a0, a1, a2, a3,…, an = regression coefficients or constants used to calibrate the equation
where
There are many statistical tests which can be performed to determine the validity of econometric models in accurately portraying
historical phenomena and to reliably project demand. Though the
constants may be found to define the general equation of the model,
it is possible that the range of error associated with the equation may
be large or that the explanatory variables chosen do not directly
determine the variation in the dependent variable.
There may be a tendency when performing sophisticated mathematical modeling to become disassociated from the significance of
the results. It is incumbent upon the analyst to consider the reasonableness as well as the statistical significance of the model. Adequate
consideration must be given to the rationality of the functional form
and variables chosen for the analysis, and to the logic associated with
calibrated constants.
In many cases it is essential to determine the sensitivity of forecasts to changes in the explanatory variables. If a particular design
parameter being forecast varies considerably with a change in a
dependent variable, and there is a significant degree of unreliability
in this independent variable, then a great deal of confidence cannot
be placed upon the forecast and, more importantly, the design based
upon the forecast. Tests are usually performed to determine the
explanatory power of the independent variables and their interrelationships. The analyst should carefully investigate the sensitivity of
projections within the expected variation of explanatory variables. It
is also possible that certain explanatory variables do not significantly
affect the modeling equation and the need for collecting the data
associated with these variables required for projections could be
159
Airport Planning
eliminated. An illustration of the application of simple linear regression analysis is presented in Example Problem 5-3.
Example Problem 5-3 The historical data shown in Table 5-1 could also be used to
prepare a forecast of the annual passenger enplanements at the study airport in
the design years 2010 and 2015 using a simple regression analysis.
In applying simple regression analysis to these data, let us assume that a relationship between the study airport annual enplanements (ENP) and the study
area population (POP) is to be examined. Therefore, it is assumed that a linear
relationship of the form shown in Eq. (5-1) exists between the variables.
ENP = a0 + a1(POP)
Using a standard regression analysis computer program the relationship is found
to be
ENP = −3,047,032 + 13.8633(POP)
where the coefficient of determination R2 is 0.983815, the coefficient of correlation
is 0.991874, and the standard error of the estimate, σyest is 55,520.9.
The regression line and the data points upon which this regression line is based
are shown in Fig. 5-5.
The coefficient of determination indicates that there is an extremely good
relationship between the annual enplanements at the study airport and the study
area population, that is, 98.4 percent of the variation in the study airport annual
enplanements is explained by the variation in the study area population.
The standard error of the estimate, however, indicates that there is a large
range of error associated with forecasting with this equation, that is, there is a
68 percent probability that the forecast of annual enplanements at the study
airport will have an error range of ± 55,520.9 annual enplanements. This may
Annual Airport Enplanement (Thousands)
160
2000
1600
ENP = –3047032 + 13.8633 POP
1200
800
400
200
300
Study Area Population (Thousands)
FIGURE 5-5 Trend line forecast of study area population for Example
Problem 5-3.
400
Forecasting for Airport Planning
or may not be too high depending on the level of annual operations forecast in
the future and the sensitivity of various components of the airport system to
such variations.
Using a trend projection, it is forecast that the area population in the year
2010, as shown on Fig. 5-6, is expected to be 363,000. The forecast of the annual
enplanements at the airport in the year 2010 can be found by substitution into
the regression equation yielding 1,985,300 annual enplanements. Similarly,
if the forecast of the area population in the year 2015 is expected to be 410,000,
then the forecast of the annual enplanements at the airport in the year 2015 is
found to be 2,636,900.
Given the range in the standard error of the estimate, it could be expected that
in the year 2010 there is a probability of 68 percent that the forecast could range
between 1,985,300 ± 55,500, or from 1,929,800 to 2,040,800 annual enplanements
about 68 percent of the time. Similarly, it could be expected that in the year
2015 the forecast could range between 2,636,900 ± 55,500, or from 2,581,900 to
2,692,400. It is likely that this range in the forecasts is acceptable since it represents
about a 2 to 3 percent error.
It is interesting to compare the results found by the three different
techniques used in Example Problems 5-1 through 5-3. The results
compare very well and it gives one some degree of confidence in the
results when the three forecasts compare well. This is called redundancy in forecasting.
Based upon the results found in these example problems, a preferred forecast would be developed. If there is no reason to suspect
600
Study Area Population (Thousands)
Historical Data
Forecast
500
410
400
363
300
200
2000
2005
Year
2010
FIGURE 5-6 Trend line forecast of study area population for Example
Problem 5-3.
2015
161
162
Airport Planning
that one technique is better than another, then a simple average might
be used to develop the preferred forecast. If this is done in these
examples, then the preferred forecast for the year 2010 is about
2,000,000 annual enplaned passengers and in the year 2015 is 2,600,000
annual enplaned passengers.
The Federal Aviation Administration utilizes econometric models
to determine national forecasts of U.S. aviation demand. The FAA
Aerospace Forecast [8] provides a 12-year outlook and view of the
immediate future for aviation. It is updated in March each year and
includes aggregate level forecasts of the following:
• Passenger enplanements, revenue passenger miles, fleet, and
hours flown for large carriers and regional commuters
• Cargo revenue ton miles and cargo fleet for large air carriers
• Fleet, hours, and pilots for general aviation
• Activity forecasts for FAA and contract towers by major user
category
The FAA Long Range Aerospace Forecasts [9] is a long range forecast that extends the 12-year forecast to a longer time horizon, typically for a period of 25 years. This forecast contains projections of
aircraft, fleet and hours, air carrier and regional/commuter passenger enplanements, air cargo freight revenue ton-miles, pilots, and
FAA workload measures.
The success in applying mathematical modeling techniques to
ascertain the level of future activity depends to a large extent on the
certainty associated with the independent variables and the relative
influence of these variables on the dependent variable. Simple and
multiple regression analysis methods are often applied to a great
variety of forecasting problems to determine the relationships
between transport related variables and such explanatory factors as
economic and population growth, market factors, travel impedance,
and competitive forces. Table 5-2 lists many of the variables required
for various purposes in aviation planning studies.
Forecasting Requirements and Applications
The specific forecasting needs depend on the nature and scope of the
study being undertaken. The requirements for a state aviation system
plan are very different than those required for an airport master plan.
Facility planning requires projections of the parameters which determine physical design whereas financial planning requires projections
of the cost elements and revenue sources associated with physical
development. This section outlines the general forecasting requirements for various types of airport studies and discusses the more
common methodologies used to arrive at these requirements.
Forecasting for Airport Planning
Application in Planning Studies
Forecast Variables Required
Macroforecast
National airport system needs
Revenue passengers
State or regional airport needs
Revenue passenger-miles
Airlines
Aircraft fleet
Aircraft and equipment
manufacturers
Air carrier
Investment planning
General aviation
Research and development needs
Composition
Route planning
Size
Workforce requirements
Capacity
Enplaned passengers
Aircraft operations
Microforecast
Airport facilities
Airside
Aircraft operations
Air carrier
Runways
Fleet mix
Taxiways
Capacity
Apron areas
Peak hour
Navigational aids
General aviation needs
Landside
General-aviation-based
aircraft
Passenger traffic
Gates
Enplaned/deplaned
Terminal facilities
Originating/terminating
Cargo needs
Connecting/transferring
Airlines
Curb frontage
Peaking characteristics
Parking
Cargo activity
Internal road network
Vehicle traffic
Ground access
Regional road network
Public transit
TABLE 5-2 Typical Air Transportation Forecast Variables and Their Use in
Aviation and Airport Planning
163
164
Airport Planning
The Airport System Plan
The purpose of an airport system plan is to identify the aviation development required to meet the immediate and future aviation needs of
a region, state, or metropolitan area [17]. It recommends the general
location and characteristics of new and expanded airports, shows the
timing, phasing, and estimated cost of development, and identifies
revenue sources and legislation for the implementation of the plan.
The aviation system plan also provides a basis for the definitive and
detailed development of the individual airports in the system.
The primary forecasting requirement for the airport system plan
is a projection of the level of aviation activity during the planning
period. The forecasts are usually made on an annual basis for the
planning entity as a whole and are then proportioned among the various individual airports within this entity. Specific projections are
generally made for total aircraft operations, air carrier and general
aviation operations, based aircraft, total air cargo, and passenger
enplanements for the short-, medium-, and long-range time frames
within the planning period. These demand projections are compared
to the inventory of physical facilities to determine development
needs. It should be emphasized that these projections are normally
made in a very aggregate fashion and tend to examine overall determinates of regional activity rather than the specific factors affecting
local activity.
The preparation of a forecast for a system plan is initiated by the
collection of historical data indicative of the various components of
aviation activity. These data normally include broad measures of
socioeconomic activity as well as aviation activity statistics. Due to
the fact that data collection is very expensive, most of the data collection in a system plan depends primarily on secondary or existing
sources and very little survey work is performed. Many of the overall
regional projections are made on the basis of trend projections or simple econometric models and these are then apportioned to the individual airports within the region on the basis of ratio methods. In the
analysis of observed trends and the preparation of future forecasts,
broad indicators are generally used including an examination of the
consistency and realization of past trends and a comparison of growth
rates and economic indicators.
The Airport Master Plan
The purpose of the airport master plan is to provide the specific
details for the future development of an individual airport to satisfy
aviation needs consistent with community objectives. The airport
master plan requires detailed projections of the level of demand on
the various facilities associated with the airport. Various concepts
and alternatives for development are examined and evaluated, and
recommendations are made relative to the prioritizing, scheduling,
Forecasting for Airport Planning
and financing of the plan [3]. Though the basis for projections in a
system plan is the aggregate level of annual demand, this is not sufficient for the master plan. Projections must be made for magnitude,
nature, and variation of demand on a monthly, daily, and hourly basis
on the many facilities located at the airport.
Annual forecasts of airport traffic during the planning period are
the basis for the preparation of the detailed forecasts in the master
plan. These forecasts are made for each type of major airport user
including air carrier, commuter, and general aviation aircraft and are
often expressed in terms of upper and lower bounds. The master plan
forecasts are usually made under both constrained and unconstrained
conditions. An unconstrained forecast is one which is made relative
to the potential aviation market in which the basic factors which tend
to create aviation demand are utilized without regard to any constraining factors that could affect aviation growth at the location. A
constrained forecast is one which is made in the context of alternative
factors which could limit growth at the specific airport. Constraining
factors addressed in master plans include limitations on airport
capacity due to land availability and noise restrictions, the development of alternative reliever airports to attract general aviation
demand, policies which alter access to airports by general aviation
and commuter aircraft operations, and the availability and cost of
aviation fuel. The determination of the level of general aviation activity at an airport can be significantly changed when land availability is
restricted, thereby placing limits on airside capacity. The available
capacity may be utilized in the context of policies which favor commercial over general aviation growth.
Specific forecasts made for a master plan include the annual,
daily, and peak hour operations by air carrier, commuter, general
aviation, cargo, and military aircraft, passenger enplanements, and
annual cargo tonnage, as well as daily and hourly ground access system and parking demand. Projections are also made for the mix or
types of aircraft in each of the categories which will utilize the airport
during the planning period. In the preparation of these forecasts
some variables are projected directly and others are derived from
these projections. For example, annual passenger enplanements
might be forecasted from an econometric model and then, based
upon exogenous estimates of average air carrier fleet passenger
capacity and boarding seat load factors, annual air carrier operations
could be derived from these data. Guidance is provided by FAA
[3, 10] for forecasting the various elements of the master plan and
FAA recommends a tabular format for presenting forecasts for review.
An example is presented in Table 5-3. Although the activity elements
shown in the table refer to annual estimates, master plan forecasts
will also require peak period activity levels for the planning of many
airport facilities, and depending on the situation, seasonal, monthly,
daily, and/or time-of-day demands must be forecast.
165
166
Base Yr
Level
Passenger Enplanements
Air Carrier
Commuter
Total
Operations
Itinerant
Air carrier
Commuter/air taxi
Total Commercial
Operations
General aviation
Military
Local
General aviation
Military
Total Operations
Instrument Operations
Peak Hour Operations
Cargo/mail (Enplaned +
Deplaned Tons)
A. Forecast Levels and Growth Rates (Sample Data Shown)
Specify Base Year: 2007
Average Annual Compound Growth Rates
Base Yr +
Base Yr +
Base Yr +
Base Yr +
Base Yr
Base Yr Base Yr Base Yr
1 yr
5 yr
10 yr
15 yr
to +1
to +5
to +10
to +15
868,981
136,184
1,005,165
904,400
143,000
1,047,400
1,021,000
179,000
1,200,000
1,273,000
234,000
1,507,000
1,587,000
306,000
1,893,000
4.1%
5.0%
4.2%
3.3%
5.6%
3.6%
3.9%
5.6%
4.1%
4.1%
5.5%
4.3%
25,155
18,100
43,225
25,700
18,800
44,500
28,000
22,000
50,000
33,600
24,700
58,300
40,000
28,000
68,000
2.2%
3.9%
2.9%
2.2%
4.0%
2.9%
2.9%
3.2%
3.0%
3.1%
3.0%
3.1%
40,124
3,124
41,600
3,124
47,000
3,124
52,000
3,124
57,500
3,124
3.7%
0.0%
3.2%
0.0%
2.6%
0.0%
2.4%
0.0%
16,167
2,436
105,106
206,391
40
16,800
16,700
2,436
108,360
209,000
42
18,010
17,500
2,436
120,060
220,000
44
23,100
18,500
2,436
134,360
230,000
47
30,200
19,500
2,436
150,560
241,000
50
39,500
3.3%
0.0%
3.1%
1.3%
5.0%
7.2%
1.6%
0.0%
2.7%
1.3%
1.9%
6.6%
1.4%
0.0%
2.5%
1.1%
1.6%
6.0%
1.3%
0.0%
2.4%
1.0%
1.5%
5.9%
Based Aircraft
Single Engine (Nonjet)
Multi Engine (Nonjet)
Jet Engine
Helicopter
Other
Total
90
14
10
2
0
116
Base Yr
Level
Average Aircraft Size
(Seats)
Air carrier
Commuter
Average Enplaning Load
Factor
Air carrier
Commuter
GA Operations per Based
Aircraft
91
15
11
2
0
119
Base Yr +
1 yr
93
94
20
25
15
19
3
3
0
0
131
141
B. Operational Factors
Base Yr +
Base Yr +
5 yr
10 yr
95
30
23
4
0
152
1.1%
7.1%
10.0%
0.0%
0.0%
2.6%
0.7%
7.4%
8.4%
8.4%
0.0%
2.5%
0.4%
6.0%
6.6%
4.1%
0.0%
2.0%
0.4%
5.2%
5.7%
4.7%
0.0%
1.8%
Base Yr +
15 yr
105.0
36.0
106.0
38.0
108.0
40.0
111.0
46.0
115.0
52.0
65.8%
41.8%
485
66.4%
40.0%
490
67.5%
40.6%
492
68.2%
41.2%
500
69.0%
42.0%
507
Note: Show base plus one year if forecast was done. If planning effort did not include all forecast years shown interpolate years as needed, using average annual
compound growth rates.
167
TABLE 5-3
Template for Summarizing and Documenting Airport Planning Forecasts
168
Airport Planning
For the most part, the methods used in the study of new airports
are similar to those used for existing airports. However, the principal
difference is the inability of the analyst to obtain a local historical
database to generate extrapolation trends, market shares, or econometric models. To overcome this deficiency, an attempt is usually
made to forecast by drawing an analogy between the subject airport
and other existing airports which demonstrate similar traffic experience, and which are located in areas possessing similar socioeconomic, demographic, and geographic characteristics. Forecasts are
then made for the airport under consideration by using these airports
as surrogates and adjustments are performed to accommodate
expected differences between the airports. In the past, the Air Transport Association and the Federal Aviation Administration have collected and tabulated a significant amount of data for many airports.
These data have included the number and distribution of commercial
air carrier operations, fleet mix, and passengers on a peak and average monthly, daily, and hourly basis. It is apparent that one may
expect a rather high degree of uncertainty associated with forecasting
through such an analogy.
The Future Aviation Forecasting Environment
Many of the forecasts made by the various aviation-related organizations become biased by the impact of recent events. Forecasts made in
the early 1960s showed rather moderate growth, whereas those made
in the late 1960s showed fairly ambitious growth. These forecasts
were made in the context of expectations which reflected the behavior of aviation at the time when they were made. In the 1970s and
1980s, the overall economic conditions, the availability and cost of
petroleum-based fuels, and airline deregulation considerably affected
aviation. Forecasts made in this era attempted to analyze the impact
of these factors in projecting the demand for aviation in the future.
The Federal Aviation Administration and numerous other transportation organizations are always looking into the future of aviation
[2, 12]. As far as future trends in air travel are concerned, it is expected
that there will be a greater growth of international air traffic which has
been attributed to the globalization of the airline industry and to
changing market forces in the United States. The factors which have
contributed to the rise of the U.S. air transportation industry are
changing. The steady decline in the real cost of air travel has reached
a point in which the unit costs in the 1990s will remain steady or slowly
rise. The increased quality of service from improvements in the speed,
comfort, convenience, and safety of air travel has been largely realized. Past demographic and cultural factors, such as the baby boom,
are declining in importance. The rise in family discretionary income
has peaked and the use of discretionary income for air travel is meeting
Forecasting for Airport Planning
competition from mortgages, savings, and luxury goods. Foreign
travel by U.S. citizens will be adversely affected by the decline in the
exchange value of the dollar. Furthermore, this factor will encourage
foreign nationals to travel to the United States [12, 13, 14].
Conferences related to aviation forecasting methodologies [10]
concluded that financial concerns and forces concerns are forcing the
aviation industry to place more emphasis on short-term forecasting
methods. This is not only the case with the airlines but airports are
also shortening their planning horizons. Throughout the aviation
industry there is a shift to simpler forecasting techniques requiring
fewer variables and less detailed data. A wider use is being made of
forecasting techniques which depend less on mathematical modeling
and more on an analysis of different scenarios, judgment, and market
segmentation. Scenarios are used to test basic assumptions and to
explore alternatives. Although judgment has always played a significant role in demand forecasting it is becoming more important as a
subjective test of the reality associated with forecasting outcomes.
There is a growing recognition that airline management strategies are
important forces shaping the future of aviation development.
To adequately cope with the uncertainties associated with the traditional air transportation forecasting process and to react in a timely
manner to inaccuracies found in estimates, the planning process is
emerging into a phase-oriented, continuing process. For example, the
FAA prepares annual forecasts of aviation activity on a national and
terminal area basis which extend several years into the future [8, 9,
18]. Due to the high costs associated with the traditional planning
process and the implementation of physical design changes, and the
apparent inability to forecast with any degree of certainty, it is essential that planning techniques be developed which can respond to
changes in the demand parameters prior to the investment decision.
Perhaps the key to such a process is the recognition of the interaction
of demand to supply parameters. The knowledge of the sensitivity of
a physical facility component to a variation in demand can lead to
more informed decisions and an understanding of the flexibility in
facility design. A continued monitoring of the need for physical facilities in light of changing demand requirements provides a sound
basis for the investment decision. Recognition of the uncertainties in
the demand forecasting process can prevent a wasteful commitment
of valuable resources. Explicit treatment of the variability of demand
projections and facility modification recommendations though the
use of sensitivity and tradeoff analyses is warranted.
References
1. Airport Aviation Activity Forecasting—A Synthesis of Airport Practice, ACRP
Synthesis 2, Airport Cooperative Research Program, Transportation Research
Board, Washington, D.C., 2007.
169
170
Airport Planning
2. Airports in the 21st Century, Conference Proceedings (Washington, April 2000),
Transportation Research Circular Number E-C027, Transportation Research
Board, Washington, D.C., March 2001.
3. Airport Master Plans, Advisory Circular, AC 150/5070-6B, Federal Aviation
Administration, Washington, D.C., 2007.
4. Airport System Capacity, Strategic Choices, Special Report No. 226, Transportation
Research Board, Washington, D.C., 1990.
5. Assumptions and Issues Influencing the Future Growth of the Aviation Industry,
Circular No. 230, Transportation Research Board, Washington, D.C., August
1981.
6. Aviation Demand Forecasting—a Survey of Methodologies, Transportation
Research E-Circular No. E-C040, Transportation Research Board, Washington,
D.C., August 2002.
7. Aviation Forecasting Methodology: A Special Workshop, Circular No. 348,
Transportation Research Board, Washington, D.C., August 1989.
8. FAA Aerospace Forecast, Fiscal Years 2008–2025, Federal Aviation Administration,
Washington, D.C., March 2008.
9. FAA Long Range Aerospace Forecasts, Fiscal Years 2020, 2025, and 2030, Federal
Aviation Administration, Washington, D.C., September 2007.
10. Forecasting Civil Aviation Activities, Circular No. 372, Transportation Research
Board, Washington, D.C., 1991.
11. Forecasting Methods for Management, 5th ed., S. G. Makridakis, John Wiley &
Sons, Inc., New York, N.Y., 1989.
12. Future Aviation Activities, 12th International Workshop, (Washington, September
2002), Circular No. E-C051, Transportation Research Board, Washington, D.C.,
January 2003.
13. Future Development of the U.S. Airport Network, Preliminary Report and
Recommended Study Plan, Transportation Research Board, Washington, D.C.,
1988.
14. Future of Aviation, Circular No. 329, Transportation Research Board, Washington,
D.C., 1988.
15. Guide for the Planning of Small Airports, Roads and Transportation Association
of Canada, Ottawa, Canada, 1980.
16. Manual on Air Traffic Forecasting, 3d ed., International Civil Aviation
Organization, Montreal, Canada, 2006.
17. The Airport System Planning Process, Advisory Circular, AC 150/5070-7, Federal
Aviation Administration, Washington, D.C., 2004.
18. Terminal Area Forecast Summary, Fiscal Years 2007–2025, Federal Aviation
Administration, Washington, D.C., 2007.
19. Trends and Issues in International Aviation, Circular No. 393, Transportation
Research Board, Washington, D.C., 1992.
PART
Airport Design
CHAPTER 6
Geometric Design
of the Airfield
CHAPTER 7
Structural Design of
Airport Pavements
CHAPTER 8
Airport Lighting,
Marking, and Signage
CHAPTER 9
Airport Drainage
CHAPTER 10
Planning and Design
of the Terminal Area
2
This page intentionally left blank
CHAPTER
6
Geometric Design
of the Airfield
Airport Design Standards
In order to provide assistance to airport designers and a reasonable
amount of uniformity in the design of airport facilities for aircraft
operations, design guidelines have been prepared by the FAA [6] and
the ICAO [2, 3, 4]. Any design criteria involving the widths, gradients, separations of runways, taxiways, and other features of the aircraft operations area must necessarily incorporate wide variations in
aircraft performance, pilot technique, and weather conditions.
The FAA design criteria provide uniformity at airport facilities in
the United States and serve as a guide to aircraft manufacturers and
operators with regard to the facilities which may be expected to be
available in the future. The FAA design standards are published in
Advisory Circulars which are revised periodically as the need arises [1].
The ICAO strives toward uniformity and safety on an international
level. Its standards, which are very similar to the FAA standards, apply
to all member nations of the Convention on International Civil Aviation and are published as Annex 14 to that convention [2]. Requirements for military services are so specialized that they are not included
in this chapter.
The design standards prepared by the FAA and the ICAO are presented in the text which follows under the general headings of airport
classification, runways, taxiways, and aprons. The material is organized so that the various criteria may be readily compared. It is
incumbent upon airport planners to review the latest specifications
for airport design at the time studies are undertaken due to the fact
that changes are incorporated as conditions dictate.
The FAA presents guidelines for airfield design in a series of
Advisory Circulars. There are more than 200 Advisory Circulars pertaining to different aspects of airport planning and design, a complete list
of which may be found on the FAA’s website at http://www.faa.gov.
173
174
Airport Design
Advisory Circular 150/5300-13 “Airport Design” is the primary source
of most airfield design standards. Originally published in 1989, AC
150/5300-13 has been updated 15 times as of 2010. The reader is
encouraged to visit the FAA’s website for the latest updates to this and
any Advisory Circulars when performing airport planning and design
work, as they are updated often.
Airport Classification
For the purpose of stipulating geometric design standards for the
various types of airports and the functions which they serve, letter
and numerical codes and other descriptors have been adopted to
classify airports.
For design purposes, airports are classified based on the aircraft
they accommodate. While at any airport, a wide variety of aircraft,
from small general aviation piston-engine aircraft to heavy air transport aircraft, will use the airfield, airports are designed based on a
series of “critical” or “design” aircraft. These aircraft are selected from
the fleet using the airport as those most critical to airfield design. The
FAA defines the term critical aircraft as the aircraft most demanding
on airport design that operates at least 500 annual itinerant operations at a given airport. In many cases, more than one critical aircraft
will be selected at an airport for design purposes. For example, it is
often the smallest aircraft that is critical to the orientation of runways,
while the largest aircraft determines most of the other dimensional
specifications of an airfield.
As described in Chap. 2, certain dimensional and performance
characteristics of the critical aircraft determine the airport’s airport
reference code. The airport reference code is a coding system used to
relate the airport design criteria to the operational and physical
characteristics of the aircraft intended to operate at the airport.
It is based upon the aircraft approach category and the airplane
design group to which the aircraft is assigned. The aircraft approach
category, as shown in Table 6-1, is determined by the aircraft
approach speed, which is defined as 1.3 times the stall speed in the
landing configuration of aircraft at maximum certified landing
weight [6].
The airplane design group (ADG) is a grouping of aircraft based
upon wingspan or tail height, as shown in Table 6-2. An airplane
design group for a particular aircraft is assigned based on the greater
(higher Roman numeral) of that associated with the aircraft’s wingspan or tail height.
The airport reference code is a two designator code referring to
the aircraft approach category and the airplane design group for
which the airport has been designed. For example, an airport reference code of B-III is an airport designed to accommodate aircraft
Geometric Design of the Airfield
Category
Approach Speed, kn
A
<91
B
91 –120
C
121 –140
D
141 –166
E
>166
1 kn is approximately 1.15 mi/h
TABLE 6-1
Aircraft Approach Categories
with approach speeds from 91 to less than 121 kn (aircraft approach
category B) with wingspans from 79 to less than 118 ft or tail heights
from 30 to less than 45 ft (airplane design group III). The FAA publishes a list of the airport reference codes for various aircraft in Advisory Circular 150/5300-13 “Airport Design” [6].
As an example, an airport designed to accommodate the Boeing
767-200 which has an approach speed of 130 kn (aircraft approach
category C) and a wingspan of 156 ft 1 in (airplane design group IV)
would be classified with an airport reference code C-IV.
The ICAO uses a two-element code, the aerodrome reference code, to
classify the geometric design standards at an airport [2, 3]. The code
elements consist of a numeric and alphabetic designator. The aerodrome code numbers 1 through 4 classify the length of the runway
available, the reference field length, which includes the runway length
and, if present, the stopway and clearway. The reference field length
is the approximate required runway takeoff length converted to an
equivalent length at mean sea level, 15°C, and zero percent gradient.
The aerodrome code letters A through E classify the wingspan and
outer main gear wheel span for the aircraft for which the airport has
been designed.
Group Number
Tail Height, ft
Wingspan, ft
I
<20
<49
II
20 – <30
49 – <79
III
30 – <45
79 –<118
IV
45 – <60
118 – <171
V
60 – <66
171 – <214
VI
66 – <80
214 – <262
TABLE 6-2
Aircraft Design Groups
175
176
Airport Design
Code
Number
Reference
Field Length,
m
Code
Letter
Wingspan, m
Distance
between Outside
Edges of Main
Wheel Gear, m
1
<800
A
<15
<4.5
2
800–<1200
B
15–<24
4.5–<6
3
1200–<1800
C
24–<36
6–<9
4
≥1800
D
36–<52
9–<14
E
52–<65
9–<14
F
65–<80
14–<16
TABLE 6-3
ICAO Aerodrome Reference Codes
These aerodrome reference codes are given in Table 6-3. For example, an airport which is designed to accommodate a Boeing 767–200
with an outer main gear wheel span of width of 34 ft 3 in (10.44 m),
a wingspan of 156 ft 1 in (48 m), at a maximum takeoff weight of
317,000 lb, requiring a runway length of about 6000 ft (1830 m) at sea
level on a standard day, would be classified by ICAO with an aerodrome reference code of 4-D. It will be noted that this classification
system does not explicitly include the function of the airport, the service it renders, or the type of aircraft accommodated.
There is an approximate correspondence between the airport reference code of the FAA and the aerodrome reference code of the ICAO
[2, 3]. The FAA’s aircraft approach category of A, B, C, and D are
approximately the same as the ICAO aerodrome code numbers 1, 2,
3, and 4, respectively. Similarly the FAA’s airplane design groups of I,
II, III, IV, and V approximately correspond to ICAO aerodrome code
letters A, B, C, D, and E.
Utility Airports
A utility airport is defined as one which has been designed, constructed,
and maintained to accommodate approach category A and B aircraft [6].
The specifications for utility airports are grouped for small aircraft,
those of maximum certified takeoff weights of 12,500 lb or less, and
large aircraft, those with maximum certified takeoff weight in excess
of 12,500 lb.
Design specifications for utility airports are governed by the airplane design group and the types of approaches authorized for the
airport runway, that is, visual, nonprecision instrument or precision
instrument approaches.
Utility airports for small aircraft are called basic utility stage I, basic
utility stage II, and general utility stage I. Utility airports for large aircraft
Geometric Design of the Airfield
are called general utility stage II. Utility airports are further grouped
for either visual and nonprecision instrument operations or precision
instrument operations. The visual and nonprecision instrument operation utility airports are the basic utility stage I, basic utility stage II,
or general utility stage I airports. The precision instrument operation
utility airport is the general utility stage II airport.
A basic utility stage I airport has the capability of accommodating
about 75 percent of the single engine and small twin engine aircraft
used for personal and business purposes. This generally means aircraft
weighing on the order of 3000 lb or less is given the airport reference
code B-I, which indicates that it accommodates aircraft in aircraft
approach categories A and B and aircraft in airplane design group I.
A basic utility stage II airport has the capability of accommodating
all of the airplanes of a basic utility stage I airport plus some small
business and air taxi-type airplanes. This generally means aircraft
weighing on the order of 8000 lb or less is also given the airport reference code B-I. A general utility stage I airport accommodates all small
aircraft. It is assigned the airport reference code of B-II. A general utility stage II airport serves large airplanes in aircraft approach categories
A and B and usually has the capability for precision instrument operations. It is assigned the airport reference code of B-III.
Transport Airports
A transport airport is defined as an airport which is designed, constructed, and maintained to accommodate aircraft in approach categories C, D, and E [6]. The design specifications of transport airports
are based upon the airplane design group.
Runways
A runway is a rectangular area on the airport surface prepared for the
takeoff and landing of aircraft. An airport may have one runway
or several runways which are sited, oriented, and configured in a
manner to provide for the safe and efficient use of the airport under a
variety of conditions. Several of the factors which affect the location,
orientation, and number of runways at an airport include local weather
conditions, particularly wind distribution and visibility, the topography of the airport and surrounding area, the type and amount of air
traffic to be serviced at the airport, aircraft performance requirements,
and aircraft noise [2].
Runway Configurations
The term “runway configuration” refers to the number and relative
orientations of one or more runways on an airfield. Many runway
configurations exist. Most configurations are combinations of several
177
178
Airport Design
basic configurations. The basic configurations are (1) single runways,
(2) parallel runways, (3) intersecting runways, and (4) open-V runways.
Single Runway
This is the simplest of the runway configurations and is shown in
Fig. 6-1. It has been estimated that the hourly capacity of a single
runway in VFR conditions is somewhere between 50 and 100 operations per hour, while in IFR conditions this capacity is reduced to
50 to 70 operations per hour, depending on the composition of the
aircraft mix and navigational aids available [4].
Parallel Runways
The capacities of parallel runway systems depend on the number of
runways and on the spacing between the runways. Two, three, and
four parallel runways are common. The spacing between parallel
runways varies widely. For the purpose of this discussion, the spacing
is classified as close, intermediate, and far, depending on the centerline separation between two parallel runways. Close parallel runways are spaced from a minimum of 700 ft (for air carrier airports) to
less than 2500 ft [5]. In IFR conditions an operation of one runway is
dependent on the operation of other runway. Intermediate parallel
runways are spaced between 2500 ft to less than 4300 ft [5]. In IFR
conditions an arrival on one runway is independent of a departure on the other runway. Far parallel runways are spaced at least
4300 ft apart [5]. In IFR conditions the two runways can be operated independently for both arrivals and departures. Therefore,
FIGURE 6-1 Single runway configuration: San Diego International Airport (NOAA
Approach Charts).
Geometric Design of the Airfield
FIGURE 6-2
Example of parallel runway configuration: Orlando International Airport.
as noted earlier, the centerline separation of parallel runways determines the degree of interdependence between operations on each of
the parallel runways. It should be recognized that in future the spacing requirements for simultaneous operations on parallel runways
may be reduced. If this occurs, new spacing can be applied to the
same classifications. Figure 6-2 illustrates an airport with multiple
parallel runways with various spacing.
If the terminal buildings are placed between parallel runways,
runways are always spaced far enough apart to allow room for the
buildings, the adjoining apron, and the appropriate taxiways. When
there are four parallel runways, each pair is spaced close, but the
pairs are spaced far apart to provide space for terminal buildings.
In VFR conditions, close parallel runways allow simultaneous
arrivals and departures, that is, arrivals may occur on one runway
while departures are occurring on the other runway. Aircraft operating on the runways must have wingspans less than 171 ft (airplane
design groups I through IV, see Table 6-2) for centerline spacing at the
minimum of 700 ft [5]. If larger wingspan aircraft are operating on
these runways (airplane design groups V and VI), the centerline spacing must be at least 1200 ft for such simultaneous operations [5]. In
either case, wake vortex avoidance procedures must be used for simultaneous operations on closely spaced parallel runways. Furthermore,
simultaneous arrivals to both runways or simultaneous departures
179
180
Airport Design
from both runways are not allowed in VFR conditions for closely spaced
parallel runways. In IFR conditions, closely spaced parallel runways cannot be used simultaneously but may be operated as dual-lane runways.
Intermediate parallel runways may be operated with simultaneous arrivals in VFR conditions. Intermediate parallel runways may
be operated in IFR conditions with simultaneous departures in a nonradar environment if the centerline spacing is at least 3500 ft and in a
radar environment if the centerline spacing is at least 2500 ft [5].
Simultaneous arrivals and departures are also permitted if the centerline spacing is at least 2500 ft if the thresholds of the runways are not
staggered [5]. There are times when it may be desirable to stagger the
thresholds of parallel runways. The staggering may be necessary
because of the shape of the acreage available for runway construction, or it may be desirable for reducing the taxiing distance of takeoff
and landing aircraft. The reduction in taxiing distance, however, is
based on the premise that one runway is to be used exclusively for
takeoff and the other for landing. In this case the terminal buildings
are located between the runways so that the taxiing distance for
each type of operation (takeoff or landing) is minimized. If the runway
thresholds are staggered, adjustments to the centerline spacing requirement are allowed for simultaneous arrivals and departures [5]. If the
arrivals are on the near threshold then the centerline spacing may be
reduced by 100 ft for each 500 ft of threshold stagger down to a minimum centerline separation of 1000 ft for aircraft with wingspans up
to 171 ft and a minimum of 1200 ft for larger wingspan aircraft. If the
arrivals are on the far threshold the centerline spacing must be
increased by 100 ft for each 500 ft of threshold stagger. Simultaneous
arrivals in IFR conditions are not permitted on intermediate parallel
runways but are permitted on far parallel runways with centerline
spacings of at least 4300 ft [5].
The hourly capacity of a pair of parallel runways in VFR conditions varies greatly from 60 to 200 operations per hour depending on
the aircraft mix and the manner in which arrivals and departures are
processed on these runways [4]. Similarly, in IFR conditions the hourly
capacity of a pair of closely spaced parallel runways ranges from
50 to 60 operations per hour, of a pair of intermediate parallel runways from 60 to 75 operations per hour, and for a pair of far parallel
runways from 100 to 125 operations per hour [4].
A dual-lane parallel runway consists of two closely spaced parallel runways with appropriate exit taxiways. Although both runways
can be used for mixed operations subject to the conditions noted
above, the desirable mode of operation is to dedicate the runway farthest from the terminal building (outer) for arrivals and the runway
closest to the terminal building (inner) for departures. It is estimated
that a dual-lane runway can handle at least 70 percent more traffic
than a single runway in VFR conditions and about 60 percent more
Geometric Design of the Airfield
traffic than a single runway in IFR conditions. It is recommended that
the two runways be spaced not less than 1000 ft apart (1200 ft, where
particularly larger wingspan aircraft are involved). This spacing also
provides sufficient distance for an arrival to stop between the two
runways. A parallel taxiway between the runways will provide for a
nominal increase in capacity, but is not essential. The major benefit of
a dual-lane runway is to provide an increase in IFR capacity with
minimal acquisition of land [7, 14].
Intersecting Runways
Many airports have two or more runways in different directions crossing each other. These are referred to as intersecting runways. Intersecting runways are necessary when relatively strong winds occur from
more than one direction, resulting in excessive crosswinds when only
one runway is provided. When the winds are strong, only one runway
of a pair of intersecting runways can be used, reducing the capacity of
the airfield substantially. If the winds are relatively light, both runways can be used simultaneously. The capacity of two intersecting
runways depends on the location of the intersection (i.e., midway or
near the ends), the manner in which the runways are operated for
takeoffs and landings, referred to as the runway use strategy, and the
aircraft mix. The farther the intersection is from the takeoff end of the
runway and the landing threshold, the lower is the capacity. The highest capacity is achieved when the intersection is close to the takeoff
and landing threshold. Figure 6-3 provides an example of intersecting
runways with the intersection closer to the runway thresholds.
Open-V Runways
Runways in different directions which do not intersect are referred
to as open-V runways. This configuration is shown in Fig. 6-4. Like
intersecting runways, open-V runways revert to a single runway
when winds are strong from one direction. When the winds are light,
both runways may be used simultaneously.
The strategy which yields the highest capacity is when operations
are away from the V and this is referred to as a diverging pattern. In
VFR the hourly capacity for this strategy ranges from 60 to 180 operations per hour, and in IFR the corresponding capacity is from 50 to 80
operations per hour [4]. When operations are toward the V it is referred
to as a converging pattern and the capacity is reduced to 50 to 100
operations per hour in VFR and to between 50 and 60 operations per
hour in IFR [4].
Combinations of Runway Configurations
From the standpoint of capacity and air traffic control, a single-direction
runway configuration is most desirable. All other things being equal,
181
182
Airport Design
FIGURE 6-3 Example of intersecting runways: LaGuardia Airport, New York.
this configuration will yield the highest capacity compared with other
configurations. For air traffic control the routing of aircraft in a single
direction is less complex than routing in multiple directions. Comparing the divergent configurations, the open-V runway pattern is
more desirable than an intersecting runway configuration. In the
open-V configuration an operating strategy that routes aircraft away
from the V will yield higher capacities than if the operations are
reversed. If intersecting runways cannot be avoided, every effort
Geometric Design of the Airfield
FIGURE 6-4
Example of open-V runways: Jacksonville International Airport.
should be made to place the intersections of both runways as close as
possible to their thresholds and to operate the aircraft away from the
intersection rather than toward the intersection.
Figure 6-5 illustrates the complex runway configuration of
Chicago’s O’Hare Field, with multiple parallel, intersecting, and nonintersecting runways. It should be noted that a large capital improvement program is being undertaken to simplify the runway configuration, by adding additional parallel runways and removing many
intersecting runways. This runway redesign is being done with the
intention of improving the capacity and efficiency of airport operations at the airport. The runway configuration redesign is illustrated
in Fig. 6-6.
Runway Orientation
The orientation of a runway is defined by the direction, relative to
magnetic north, of the operations performed by aircraft on the runway. Typically, but not always, runways are oriented in such a manner that they may be used in either direction. It is less preferred to
183
184
Airport Design
FIGURE 6-5 Example of complex runway system: Chicago O’Hare International Airport.
orient a runway in such a way that operating in one direction is precluded, normally due to nearby obstacles.
In addition to obstacle clearance considerations, which will be discussed later in this chapter, runways are typically oriented based on
the area’s wind conditions. As such, an analysis of wind is essential for
planning runways. As a general rule, the primary runway at an airport should be oriented as closely as practicable in the direction of the
prevailing winds. When landing and taking off, aircraft are able to
maneuver on a runway as long as the wind component at right angles
to the direction of travel, the crosswind component, is not excessive.
The FAA recommends that runways should be oriented so
that aircraft may be landed at least 95 percent of the time with
Geometric Design of the Airfield
FIGURE 6-6 Planned simplified runway configuration: Chicago O’Hare International
Airport (Courtesy Chicago O’Hare Modernization program).
allowable crosswind components not exceeding specified limits
based upon the airport reference code associated with the critical
aircraft that has the shortest wingspan or slowest approach speed.
When the wind coverage is less than 95 percent a crosswind runway
is recommended.
The allowable crosswind is 10.5 kn (12 mi/h) for Airport Reference Codes A-I and B-I, 13 kn (15 mi/h) for Airport Reference Codes
A-II and B-II, 16 kn (18.5 mi/h) for Airport Reference Codes A-III,
B-III, C-I, C-II, C-III and C-IV, and 20 knots (23 mph) for Airport Reference Codes A-IV through D-VI [5].
ICAO also specifies that runways should be oriented so that aircraft may be landed at least 95 percent of the time with crosswind
components of 20 kn (23 mph) for runway lengths of 1500 m more,
13 kn (15 mi/h) for runway lengths between 1200 and 1500 m, and
10 kn (11.5 mi/h) for runway lengths less than 1200 m [1, 2].
185
186
Airport Design
Once the maximum permissible crosswind component is selected,
the most desirable direction of runways for wind coverage can be
determined by examination of the average wind characteristics at the
airport under the following conditions:
1. The entire wind coverage regardless of visibility or cloud ceiling
2. Wind conditions when the ceiling is at least 1000 ft and the
visibility is at least 3 mi
3. Wind conditions when ceiling is between 200 and 1000 ft
and/or the visibility is between ½ and 3 mi.
The first condition represents the entire range of visibility, from
excellent to very poor, and is termed the all weather condition. The
next condition represents the range of good visibility conditions not
requiring the use of instruments for landing, termed visual meteorological condition (VMC). The last condition represents various degrees
of poor visibility requiring the use of instruments for landing, termed
instrument meteorological conditions (IMC).
The 95 percent criterion suggested by the FAA and ICAO is applicable to all conditions of weather; nevertheless it is still useful to
examine the data in parts whenever this is possible.
In the United States, weather records can be obtained from the
Environmental Data and Information Service of the National Climatic
Center at the National Oceanic and Atmospheric Administration
located in Ashville, N.C., or from various locations found on the
Internet.
Weather data are collected from weather stations throughout the
United States on an hourly basis and recorded for analysis. The data
collected include ceiling, visibility, wind speed, wind direction,
storms, barometric pressure, the amount and type of liquid and frozen
precipitation, temperature, and relative humidity. A report illustrating the tabulation and representation of some of the data of use in
airport studies was prepared for the FAA [15]. The weather records
contain the percentage of time certain combinations of ceiling and
visibility occur (e.g., ceiling, 500 to 900 ft; visibility, 3 to 6 mi), and the
percentage of time winds of specified velocity ranges occur from different directions (e.g., from NNE, 4 to 7 mi/h). The directions are
referenced to true north.
The Wind Rose
The appropriate orientation of the runway or runways at an airport
can be determined through graphical vector analysis using a wind
rose. A standard wind rose consists of a series of concentric circles cut
by radial lines using polar coordinate graph paper. The radial lines
are drawn to the scale of the wind magnitude such that the area
between each pair of successive lines is centered on the wind direction.
Geometric Design of the Airfield
NNW
NE
i/h
m
WNW
NNE
15
NW
N
35
25
20
15
ENE
4
E
W
WSW
SE
SW
SSW
FIGURE 6-7
ESE
3.0
S
SSE
Wind rose coordinate system and template.
A typical wind rose polar coordinate system is shown on the left side
of Fig. 6-7. The shaded area indicates that the wind comes from the
southeast (SE) with a magnitude between 20 and 25 mi/h. A template
is also drawn to the same radial scale representing the crosswind
component limits. A template drawn with crosswind component limits of 15 mi/h is shown on the right side of Fig. 6-7. On this template
three equally spaced parallel lines have been plotted. The middle line
represents the runway centerline, and the distance between the middle line and each outside line is, to scale, the allowable crosswind
component (in this case, 15 mi/h). The template is placed over the
wind rose in such a manner that the centerline on the template passes
through the center of the wind rose.
By overlaying the template on the wind rose and rotating the centerline of the template through the origin of the wind rose one may
determine the percentage of time a runway in the direction of the
centerline of the template can be used such that the crosswind component does not exceed 15 mi/h. Optimum runway directions can be
determined from this wind rose by the use of the template, typically
made on a transparent strip of material. With the center of the wind
rose as a pivot point, the template is rotated until the sum of the percentages included between the outer lines is a maximum. If a wind
vector from a segment lies outside either outer line on the template
for the given direction of the runway, that wind vector must have a
crosswind component which exceeds the allowable crosswind component plotted on the template. When one of the outer lines on the
template divides a segment of wind direction, the fractional part is
estimated visually to the nearest 0.1 percent. This procedure is consistent with the accuracy of the wind data and assumes that the wind
percentage within the sector is uniformly distributed within that sector.
In practice, it is usually easier to add the percentages contained in the
187
188
Airport Design
sectors outside of the two outer parallel lines and subtract these from
100 percent to find the percentage of wind coverage.
Example Problem 6-1 As an example, assume that the wind data for all conditions
of visibility are those shown in Table 6-4. This wind data is plotted to scale as
indicated above to obtain a wind rose, as shown in Fig. 6-8.
The percentage of time the winds correspond to a given direction and velocity range is marked in the proper sector of the wind rose by means of a polar coordinate scale for both wind direction and wind magnitude. The template is rotated
about the center of the wind rose, as explained earlier, until the direction of the
centerline yields the maximum percentage of wind between the parallel lines.
Once the optimum runway direction has been found in this manner, the
next step is to read the bearing of the runway on the outer scale of the wind rose
where the centerline on the template crosses the wind direction scale. Because
true north is used for published wind data, this bearing usually will be different
Wind Speed Range, mi/h
True
Azimuth
4–15
0.0
2.4
0.4
0.1
0.0
2.9
NNE
22.5
3.0
1.2
1.0
0.5
5.7
NE
45.0
5.3
1.6
1.0
0.4
8.3
ENE
67.5
6.8
3.1
1.7
0.1
11.7
Sector
N
E
15–20
20–25
25–35
Percentage of Time
Total
90.0
7.1
2.3
1.9
0.2
11.5
ESE
112.5
6.4
3.5
1.9
0.1
11.9
SE
135.0
5.8
1.9
1.1
0.0
8.8
SSE
157.5
3.8
1.0
0.1
0.0
4.9
S
180.0
1.8
0.4
0.1
0.0
2.3
SSW
202.5
1.7
0.8
0.4
0.3
3.2
SW
225.0
1.5
0.6
0.2
0.0
2.3
WSW
247.5
2.7
0.4
0.1
0.0
3.2
W
270.0
4.9
0.4
0.1
0.0
5.4
WNW
292.5
3.8
0.6
0.2
0.0
4.6
NW
315.0
1.7
0.6
0.2
0.0
2.5
NNW
337.5
Subtotal
1.7
0.9
0.1
0.0
2.7
60.4
19.7
10.2
1.6
91.9
Calms
8.1
Total
TABLE 6-4
100.0
Example Wind Data
Geometric Design of the Airfield
N
NNW
NNE
NW
0.1
WNW
0.4
1.0
0.4
0.9
0.2
1.2
1.0
0.6
0.2
1.7
0.6
1.7 2.4 3.0
0.1 0.4
5.3
8.1
2.7
1.5
0.2
0.2
E
0.4
1.0
0.1
3.5
1.9
1.9
0.1
ESE
1.1
0.1
SE
0.3
SSW
1.7
2.3 1.9
7.1
5.8
1.7 1.8 3.8
0.8
0.4
SW
3.1
6.4
0.6
WSW
0.1
6.8
4.9
0.1 0.4
ENE
1.6
3.8
W
NE
0.5
0.1
S
SSE
FIGURE 6-8 Wind data in wind rose format.
from that used in numbering runways since runway designations are based on
the magnetic bearing. As illustrated in Fig. 6-9, a runway oriented on an azimuth
to true north of 90° to 270° (N 90° E to S 90° W true bearing) will permit operations
90.8 percent of the time with the crosswind components not exceeding 15 mi/h.
Should the wind analysis not give the desired wind coverage, the template
may then be used to determine the direction of a second runway, a crosswind
runway, which would increase the wind coverage to 95 percent. This is done by
blocking out the area between the two outer parallel lines for the direction of the
primary runway (since this has already been counted in the wind coverage for
the primary runway) and rotating the template until the percentages between
the outer parallel lines for the remaining area for another direction is maximized.
If this is done in this problem it is found that the crosswind runway should be
located in an orientation of 12° to 192° (N 12° E to S 12° W true bearing). This
will permit an additional wind coverage of 6.2 percent above that provided by
the runway oriented 90° to 270° for a total wind coverage for both runways of
97.0 percent.
Let us say that because of noise-sensitive land uses in the direction of the
optimal crosswind runway, a crosswind runway will be located at the airport
in the orientation of 30° to 210° direction which results in an additional wind
coverage of 5.8 percent. This runway orientation, called runway 3–21, is shown
in Fig. 6-10. The total wind coverage for both runways is then 96.6 percent. The
total wind coverage for a runway in the orientation of 30° to 210° direction is
found to be 84.8 percent from Fig. 6-11. The combined wind coverage of 96.6
percent for the use of either runway is shown in Fig. 6-11.
189
190
Airport Design
N
NNW
NNE
NW
0.1
0.4
1.0
0.4
0.9
0.2
WNW
1.2
1.0
0.6
0.2
1.7
0.6
1.7 2.4 3.0
W
0.1 0.4
5.3
8.1
4.9
2.7
1.5
0.1 0.4
0.2
1.7
2.3 1.9
7.1
0.2
E
6.4
3.5
5.8
1.7 1.8 3.8
0.8
0.4
SW
0.1
3.1
1.9
1.9
0.6
WSW
ENE
1.6
6.8
3.8
9
NE
0.5
0.1
0.4
0.1
ESE
1.1
1.0
0.1
0.1
SE
0.3
SSW
SSE
S
FIGURE 6-9 Wind coverage for runway 9–27, Example Problem 6–1.
21
N
NNW
NNE
NW
0.1
WNW
0.4
1.0
0.4
0.9
0.2
1.2
1.0
0.6
0.2
1.7
0.6
1.7 2.4 3.0
0.1 0.4
5.3
8.1
4.9
2.7
1.5
0.1 0.4
0.2
3.1
0.2
E
0.4
0.1
1.0
3.5
1.9
1.9
0.1
ESE
1.1
0.1
SE
0.3
SSW
1.7
2.3 1.9
7.1
5.8
1.7 1.8 3.8
0.8
0.4
SW
0.1
6.4
0.6
WSW
ENE
1.6
6.8
3.8
W
NE
0.5
0.1
S
SSE
3
FIGURE 6-10
Wind coverage for runway 3–21, Example Problem 6-1.
27
Geometric Design of the Airfield
21
N
NNW
NNE
NW
0.1
0.4
1.0
0.4
0.9
0.2
WNW
1.2
1.0
0.6
0.2
1.7
0.6
1.7 2.4 3.0
W
0.1 0.4
5.3
8.1
2.7
1.5
0.2
0.2
E
0.4
0.1
1.0
27
3.5
1.9
1.9
0.1
ESE
1.1
0.1
SE
0.3
SSW
1.7
2.3 1.9
7.1
5.8
1.7 1.8 3.8
0.8
0.4
SW
3.1
6.4
0.6
WSW
0.1
6.8
4.9
0.1 0.4
ENE
1.6
3.8
9
NE
0.5
0.1
S
SSE
3
FIGURE 6-11 Wind coverage for runways 9–27 and 3–21, Example Problem 6-1.
Estimating Runway Length
Other than orientation, planning and designing the length of a runway is critical to whether or not a particular aircraft can safely use the
runway for takeoff or landing. Furthermore, designing a runway to
accommodate a given aircraft is a difficult task, given the fact that an
aircraft’s required runway length will vary based on aircraft weight,
as well as on several ambient conditions.
As a guide to airport planners, the FAA has published Advisory
Circular 150/5325-4b, “Runway Length Requirements for Airport
Design” [17]. In this publication, procedures are defined for estimating the design runway length of aircraft, based on their maximum
takeoff weights (MTOW), certain aircraft performance specifications,
and the airport’s field elevation and temperature. The airport
design runway length is found for the critical aircraft, defined as the
aircraft which flies the greatest nonstop route segment from the airports at least 500 operations per year and requires the longest runway.
The FAA’s procedure for estimating runway length is based on the
following data:
1. Designation of a critical aircraft
2. The maximum takeoff weight of the critical aircraft at
the airport
191
192
Airport Design
3. The airport elevation
4. The mean daily maximum temperature for the hottest month
at the airport
5. The maximum different in elevation along the runway
centerline.
For the purposes of estimating runway length requirements, the
FAA groups aircraft by MGTOW. Based on the MGTOW of the critical
aircraft, the following procedures are defined:
Aircraft Less than 12,500 lb MGTOW
Critical aircraft less than or equal to 12,500 lb MGTOW are considered “small airplanes” for the purposes of estimating runway length
requirements. For these small aircraft, design runway length is based
on the aircraft’s reference approach speed, Vref .
Aircraft with Vref < 30 kn are considered short takeoff and landing
(STOL) aircraft. The design runway length for STOL aircraft is 300 ft
(92 m) at sea level. For airports at elevation above sea level, the design
runway length is 300 ft plus 0.03 ft for every foot above sea level.
For aircraft with 30 ≤ Vref < 50 kn, the design runway length at sea
level is 800 ft (244 m). For airports at elevation above sea level, the
design runway length is 800 ft plus 0.08 ft for every foot above sea
level.
For aircraft with Vref ≥ 50 kn, the design runway length is based on
the number of passenger seats in the aircraft. For those aircraft with
less than 10 passenger seats, Fig. 6-12 is referenced. This figure has
two sets of curves, one representing “95 percent of fleet,” to be used
at airports serving small communities, and one representing “100
percent of fleet,” to be applied at airports near larger metropolitan
areas.
Figure 6-12 is illustrated with an example case where the mean
daily maximum temperature at the hottest month at the airport is
59°F and elevation is sea level. A vertical line is drawn from the point
on the horizontal axis associated with 59°F to the sea level field elevation curve. A horizontal line is then drawn from the associated location on the elevation curve to the right side of the figure. The value at
the end of the horizontal line on the right side of the figure is the recommended design runway length. In this case, applying the 95 percent of fleet curve results in a design runway length of 2700 ft, while
the 100 percent of fleet curve resulting in a design runway length of
3200 ft.
For those aircraft with 10 or more passenger seats at airports at
elevation 3000 ft AMSL or less, Fig. 6-13 is referenced. At airports at
elevation greater than 3000 ft AMSL, Fig. 6-12 “100 percent of fleet” is
referenced.
Figure 6-13 is illustrated with an example case where the mean
daily maximum temperature at the hottest month at the airport is
Geometric Design of the Airfield
Airport Elevation
(feet)
95 Percent of Fleet
100 Percent of Fleet
10000
900
0
00
00
70
70
Note: Dashed lines shown in the table
are mid values of adjacent solid lines.
9000
80
00
900
800
Temperature (mean day max hot
month): 59°F (15°C)
Airport Elevation: Mean Sea
Level
0
0
Example:
8000
50
00
50
6000
00
0
40
40
0
5000
00
30
00
00
20
00
10
30
00
20
75
4000
SL
00
10
SL
50
RUNWAY LENGTH (FEET)
7000
00
For 95% = 2,700 feet (823 m)
For 100% = 3,200 feet (975 m)
60
60
00
00
Recommended Runway Length:
3000
100
50
75
100
2000
Mean Daily Maximum Temperature of the Hottest
Month of Year (Degrees F)
FIGURE 6-12 Small airplanes with fewer than 10 passenger seats (FAA AC
150/5325-4b).
90°F and elevation is 1000 ft AMSL. A vertical line is drawn from the
point on the horizontal axis associated with 90°F to the 1000 ft AMSL
field elevation curve. A horizontal line is drawn from the associated
point on the field elevation curve to the right side of the figure, where
the runway length is estimated. In this example, the design runway
length is estimated to be 4400 ft.
Aircraft Greater than 12,500 lb but Less than or Equal
to 60,000 lb MGTOW
For aircraft greater than 12,500 lb but less than or equal to 60,000 lb
MGTOW, the critical aircraft is located on Table 6-5 “75 percent of
fleet,” or Table 6-6, “100 percent of fleet.” Table 6-5 represents aircraft
that generally require less than 5000 ft of runway, while Table 6-6
represents aircraft that generally require 5000 ft or more of runway.
193
194
Airport Design
Representative Airplanes
Raytheon B80 Queen Air
Raytheon E90 King Air
Raytheon B99 Airliner
Raytheon A100 King Air
(Raytheon formerly Beech
Aircraft)
Runway Length Curves
Example: Temperature (mean day max hot month) 90°F (32°C)
Airport Elevation (mol)
1,000 feet (328 m)
Recommended Runway Length 4,400 feet (1,341 m)
Note: For airport elevations above 3,000 feet (915 m), use the
100 percent of fleet grouping in figure 2-1.
6000
Brittea-Norman
Mark III-I Trilander
Mitsubishi MU-2L
Swearigen Merlin III-A
Swearigen Merlin IV-A
Swearigen Metro II
Airport
Elevation (FT)
Runway Length (FT)
5000
00
30
00
20
00
0
1
el
ev
aL
Se
30
40
50
60
70
80
4000
90
100
110
3000
120
Mean Daily Maximum Temperature of
the Hottest Month of the Year
(Degrees F)
FIGURE 6-13 Small airplanes having 10 or more passenger seats (FAA AC
150/5325-4b).
As such, if the selected critical aircraft is found on Table 6-5, it is said
that the runway length estimated will be able to accommodate 75 percent
of the fleet. If the selected critical aircraft is found on Table 6-6, it is
said that the runway length estimated will be able to accommodate
100 percent of this size fleet.
For the design aircraft, a “useful load” of either 60 or 90 percent is
selected. A 60 percent useful load represents the condition where the
critical aircraft typically operates at 60 percent load factors, or performs
shorter range operations, requiring less fuel, while a 90 percent useful
load represents the condition where the critical aircraft typically operates at 90 percent load factors, or performs longer range operations.
For aircraft falling within the “75 percent of fleet” group as identified in Table 6-5, Fig. 6-14 is then applied, selecting either the 60 or
Geometric Design of the Airfield
Manufacturer
Model
Manufacturer
Model
Aerospatiale
Sn-601 Corvette
Dassault
Falcon 10
Bae
125–700
Dassault
Falcon 20
Beech Jet
400A
Dassault
Falcon 50/50 EX
Beech Jet
Premier I
Dassault
Falcon 900/900B
Beech Jet
2000 Starship
Israel Aircraft
Industries (LAI)
Jet Commander
1121
Bombardier
Challenger 300
IAI
Westwind
1123/1124
Cessua
500 Citation/
501 Citation Sp
Learjet
20 Series
Cessna
Citation I/II/III
Learjet
31/31A/31A ER
Cessna
525A Citation II
(CJ-2)
Learjet
35/35A/36/36A
Cessna
350 Citation
Bravo
Learjet
40/45
Cessna
550 Citation II
Mitsubishi
Mu-300 Diamond
Cessna
551 Citation
II/Special
Raytheon
390 Premier
Cessna
552 Citation
Raytheon
Hawker
400/400 XP
Cessna
560 Citation
Encore
Raytheon
Hawker
600
Cessna
560/560 XL
Citation Excel
Sabreliner
40/60
Cessna
560 Citation V
Ultra
Sabreliner
75A
Cessna
650 Citation VII
Sabreliner
80
Cessna
680 Citation
Sovereign
Sabreliner
T-39
Source: FAA AC 150/5235-4b.
TABLE 6-5
Airplanes that Make Up 75 Percent of the Fleet
90 percent useful load sides of the figure, and applied based on the
mean daily maximum temperature of the hottest month (in Fahrenheit), and the elevation of the airfield (in feet AMSL).
Figure 6-14 illustrates two examples, one for an airport at sea
level with average high temperature during the hottest month at 59°F
and a critical aircraft falling within the 75 percent of fleet category at
195
196
Airport Design
Manufacturer
Model
Bae
Corporate 800/1000
Bombardier
600 Challenger
Bombardier
601/601-3A/3ER Challenger
Bombardier
604 Challenger
Bombardier
BD-100 Continental
Cessna
S550 Citation S/II
Cessna
650 Citation III/IV
Cessna
750 Citation X
Dassault
Falcon 900C/900EX
Dassualt
Falcon 2000/2000EX
Israel Aircraft Industries (IAI)
Astra 1125
IAI
Galaxy 1126
Learjet
45 XR
Learjet
55/55B/55C
Learjet
60
Raytheon/Hawker
Horizon
Raytheon/Hawker
800/800 XP
Raytheon/Hawker
1000
Sabreliner
65/75
TABLE 6-6 Aircraft that (Including Those in Table 6-1) Make Up 100
Percent of the Fleet
60 percent useful load, and one for an airport at 1000 ft AMSL, average high temperature during the hottest month at 100°F, and a critical
aircraft falling within the 75 percent of fleet category at 90 percent
useful load. For aircraft falling within the “100 percent of fleet” group
as identified in Table 6-6, Fig. 6-15 is similarly applied.
Figure 6-15 is illustrated with two examples, one illustrating an
airport at 2000 ft AMSL with average high temperature during the
hottest month at 59°F and a critical aircraft falling within the 100 percent of fleet category at 60 percent useful load, and one illustrating an
airport at 3000 ft AMSL, average high temperature during the hottest
month at 100°F, and a critical aircraft falling within the 100 percent of
fleet category at 90 percent useful load.
Based on the runway lengths found in either Fig. 6-14 or Fig. 6-15,
an adjustment is made for any nonlevel runway gradient. Specifically, the runway length found in Fig. 6-14 or Fig. 6-15 is increased by
Geometric Design of the Airfield
9,000
8,500
8,000
RUNWAY LENGTHS (FEET)
9,000
EXAMPLE:
TEMP. = 59°F
AIRPORT ELEV. = SL
RUNWAY LENGTH = 4,550'
E
N
(F
7,500
E
RT
7,000
EL
O
RP
8,500
6,000'
0
4,00
)
ET
8,000
CLIMB LIMITATION 7,700'
O
TI
VA
CLIMB LIMITATION 8,600'
8,000
7,500
0
00
8,
AI
7,000
00
6,0
6,500
6,500
2,000
00
4,0
6,000
6,000
SL
AIRPORT ELEVATION (FEET)
5,500
5,500
0
2,00
5,000
5,000
SL
EXAMPLE:
TEMP. = 100°F
AIRPORT ELEV. = 1,000'
RUNWAY LENGTH = 7,550'
4,500
4,000
40
50
60
70
80
90
100 110 40
50
70
60
4,500
80
90
4,000
100 110
Mean Daily Maximum Temperature of Hottest Month of the Year in Degrees Fahrenheit
75 percent of feet at 60 percent
useful load
75 percent of feet at 90 percent
useful load
FIGURE 6-14 Seventy-five percent of fleet at 60 or 90 percent useful load.
CLIMB LIMITATION 11,000'
11,000
CLIMB LIMITATION 11,000'
10,500
10,500
6,0
10,000
00
9,500
9,000
8,500
00
0
8,000
SL
00
T
0
4,
O
RP
AI
R
8,000
7,500
7,000
6,500
)
6,500
(F
EE
T
00
0
2,
6,000
5,500
5,000
4,500
SL
T
OR
IO
N
6,000
0
00
2,
7,500
7,000
N(
FE
E T)
4,0
EL
EV
AT
IO
8,500
9,000
6,0
0
RUNWAY LENGTH (FEET)
0
00
8,
5,500
AT
EV
EL
P
AIR
EXAMPLE:
TEMP. = 59°F
ELEV. = 2,000'
RUNWAY LENGTH = 5,000'
5,000
EXAMPLE:
TEMP. = 100°F
ELEVATION = 3,000'
RUNWAY LENGTH = 10,500'
4,500
4,000
4,000
40 50 60 70 80 90 100 110 40 50 60 70 80 90 100 110
Mean Daily Maximum Temperature of Hottest Month of the Year in Degrees Fahrenheit
100 percent of feet at 60 percent
100 percent of feet at 90 percent
useful load
useful load
FIGURE 6-15
Hundred percent of fleet at 60 or 90 percent useful load.
RUNWAY LENGTH (FEET)
10,000
9,500
11,000
197
198
Airport Design
10 ft for every foot in elevation difference between the lowest point
and highest point on the runway.
At higher elevations, it is often the case that the required runway
length is greater for aircraft less than 12,500 lb MGTOW than for aircraft greater than 12,500 lb. If this is the case, the design runway
length would be that for the lighter aircraft. As such, airport planners
estimating runway lengths at high elevation airports should perform
runway length estimations for the smallest aircraft, in addition to that
for the selected critical aircraft.
Aircraft Greater than 60,000 lb MGTOW
For aircraft greater than 60,000 lb MGTOW, runway lengths are estimated based on the specific performance specifications of the critical
aircraft. These performance specifications may be found in the published aircraft “airport planning manuals.” These manuals may be
found on the Internet sites of the major aircraft manufacturers.
Within the aircraft airport planning manuals are performance
charts that are used to determine the aircraft’s required runway lengths
for both takeoff and landing, based on the aircraft’s operating configuration, its estimated weights during takeoff and landing, as well
as the airport elevation and average high temperature during the hottest
month.
Example Problem 6-2 illustrates the procedure for estimating runway
length using these charts.
Example Problem 6-2 Consider the situation where an airport with elevation
1000 ft AMSL and mean daily maximum temperature of the hottest month
of 84°F, is planning for a new runway to be designed for the Boeing 737-900
aircraft, equipped with Pratt & Whitney CFM56-7B27 engines. At the airport
a runway gradient of 20 ft is projected.
According to the performance specification chart, illustrated in Fig. 6-16,
found in the Boeing 737-900 airport planning manual, the maximum design
landing weight for the aircraft is 146,300 lb and the maximum design takeoff
weight is 174,200 lb.
First, estimation of required runway length for landing is performed using
the landing runway length performance chart for the aircraft. As with most
landing performance charts, runway length requirements found landing may
be found under both dry and wet runway conditions. For airport planning purposes, design runway length for landing is estimated by considering wet runway
conditions. If a landing runway length performance chart does not include wet
runway conditions, the design runway length is estimated as the runway length
found under dry runway conditions, plus 15 percent.
Figure 6-17 illustrates this example. Applying the case example, a vertical
line is drawn from the base of the horizontal axis at the location of the maximum
design landing weight (146,300 lb), up to an interpolated point between the “sea
level” and “2000 ft” (to represent the example airport’s 1000 ft elevation) wetrunway curves, and then a horizontal line is drawn to the vertical axis, where the
estimated required runway length may be found. In this example, the estimated
runway length for landing is approximately 6600 ft.
Geometric Design of the Airfield
CHARACTERISTICS
UNITS
MAX DESIGN
POUNDS
TAXI WEIGHT
MAX DESIGN
TAKEOFF WEIGHT
MAX DESIGN
LANDING WEIGHT
MAX DESIGN
ZERO FUEL WEIGHT
OPERATING
EMPTY WEIGHT (1)
MAX STRUCTURAL
PAYLOAD
SEATING CAPACITY (1)
MAX CARGO
- LOWER DECK
USABLE FUEL
KILOGRAMS
POUNDS
737–900
164,500
174,700
74,616
79,243
164,000
174,200
79,016
KILOGRAMS
POUNDS
Takeoff
Weight
146,300
KILOGRAMS
POUNDS
66,361
138,300
63,639
KILOGRAMS
POUNDS
140,300
Landing
Weight
94,580
42,901
KILOGRAMS
POUNDS
43,720
45,720
KILOGRAMS
19,831
20,738
TWO-CLASS
177
177
ALL-ECONOMY
189
189
1,835
1,835
CUBIC METERS
52.0
52.0
US GALLONS
6875
6875
LITERS
26,022
26,022
POUNDS
46,063
46,063
KILOGRAMS
20,894
20,894
CUBIC FEET
NOTE: (1) OPERATING EMPTY WEIGHT FOR BASELINE MIXED CLASS CONFIGURATION.
CONSULT WITH AIRLINE FOR SPECIFIC WEIGHTS AND CONFIGURATIONS.
FIGURE 6-16 Boeing 737–900 general airplane characteristics (Boeing Corp. document
#D6-58325-3 and FAA AC 150/5325-4B).
These charts are designed for level runways. An adjustment for runway gradient must be made by adding 10 ft of runway length for every foot of runway
gradient. In this example, an additional 200 ft of runway length is added, resulting in an adjusted runway length for landing of 6800 ft.
Second, estimation of required runway length for takeoff is performed using
the takeoff runway length performance chart for the aircraft. Oftentimes, an
aircraft will have multiple takeoff performance charts, typically for different
average high temperatures. The chart associated with the temperature nearest
the airport’s average high during the hottest month is used.
199
200
Airport Design
NOTES:
•
•
•
•
•
STANDARD DAY
AUTO SPOILERS OPERATIVE
ANTI-SKID OPERATIVE
ZERO WIND
CONSULT USING AIRLINE FOR SPECIFIC
OPERATING PROCEDURE PRIOR TO FACILITY DESIGN
9
DRY RUNWAY
FLAPS 40
WET RUNWAY
2.5
8
8,000 (2,438)
7
6,000 (1,829)
4,000 (1,219)
2.0
1.5
1,000 FEET
F.A.R. LANDING RUNWAY LENGTH
(1,000 METERS)
AIRPORT ELEVATION
FEET (METERS)
2,000 (610)
SEA LEVEL
6
5
4
MAX DESIGN LANDING WT
146,300 (66,360 KG)
1.0
3
100
110
120
130
1,000 POUNDS
50
55
60
(1,000 KILOGRAMS)
140
150
65
OPERATIONAL LANDING WEIGHT
FIGURE 6-17 Landing runway length for Boeing 737–900 (CFM56-7B27 Engines, 40°
Flaps) (Ref: Boeing Doc. D6-58325-3).
Figure 6-18 illustrates this example. Applying the case example, a vertical
line is drawn from the base of the horizontal axis at the location of the maximum
design takeoff weight (174,200 lb), up to an interpolated point between the “sea
level” and “2000 ft” curves, and then a horizontal line is drawn to the vertical
axis, where the estimated required runway length for takeoff may be found. In
this example, the estimated runway length for takeoff is approximately 8800 ft.
Considering the example’s runway gradient, an additional 200 ft of runway
length is added, resulting in an adjusted runway length for takeoff of 9000 ft.
Geometric Design of the Airfield
NOTES:
•
•
•
•
•
CFM56–7827 ENGINES RATED AT 27,300 LB SLST
NO ENGINE AIR BLEED FOR AIR CONDITIONING
ZERO WIND, ZERO RUNWAY GRADIENT
DRY RUNWAY SURFACE
CONSULT WITH USING AIRLINE FOR SPECIFIC
OPERATING PROCEDURE PRIOR TO FACILITY DESIGN
• LINEAR INTERPOLATION BETWEEN ALTITUDES INVALID
• LINEAR INTERPOLATION BETWEEN TEMPERATURES INVALID
15
4.5
14
D
E
PE
LIM
ES
TIR
13
12
3.5
11
3.0
2.5
1,000 FEET
F.A.R. TAKEOFF RUNWAY LENGTH
(1,000 METERS)
4.0
IT
STANDARD DAY + 27°F
(STD + 15°C)
10
9
8
7
2.0
6
1.5
5
S
AP
ON
TI
VA S)
E
EL TER 8)
T
E 43
OR (M (2,
P
T
R
9)
AI FEE 00
82
(1,
8,0
0
0
19)
6,0
(1,2
00
0)
4,0
(61
00
2,0
EL
V
E
L
SEA
4
1.0
5
FL
PS
15
A
FL
PS
FLA
25
MAX DESIGN TAKEOFF WT
174,200 LB (79,016 KG)
3
120 125 130 135 140 145 150 155 160 165 170 175
1,000 POUNDS
55
60
65
70
(1,000 KILOGRAMS)
75
80
OPERATIONAL TAKEOFF WEIGHT
FIGURE 6-18 Takeoff runway length for Boeing 737–900 (CFM56-7B27 Engines)
(Ref: Boeing Doc. D6-58325-3).
For design purposes, the design runway length is the longer of the required
runway lengths for landing and for takeoff. In this case, the design runway
length for this example is 9000 ft.
Runway System Geometric Specifications
The runway system at an airport consists of the structural pavement, the shoulders, the blast pad, the runway safety area, various
obstruction-free surfaces, and the runway protection zone, as shown
in Figs. 6-19 and 6-20.
201
202
Airport Design
Structural
Pavement
Runway Safety Area
Shoulder
Blast Pad
(a)
(b)
Runway Protection Zone
Runway Object Free Area
(c)
FIGURE 6-19
(d)
Runway system dimensions.
1. The runway structural pavement supports the aircraft with
respect to structural load, maneuverability, control, stability,
and other operational and dimensional criteria.
2. The shoulder adjacent to the edges of the structural pavement
resists jet blast erosion and accommodates maintenance and
emergency equipment.
3. The blast pad is an area designed to prevent erosion of the
surfaces adjacent to the ends of runways due to jet blast or
propeller wash.
4. The runway safety area (RSA) is an area surrounding the runway prepared or suitable for reducing the risk of damage to
aircraft in the event of an undershoot, overshoot, or excursion
from the runway. ICAO refers to an area similar to the runway safety area as the runway strip and the runway end safety
Inner Transitional OFZ
Runway OFZ
1
3
Inner Approach OFZ
50
FIGURE 6-20 Object-free zone dimensions.
1
Geometric Design of the Airfield
area. The runway safety area includes the structural pavement, shoulders, blast pad, and stopway, if provided. This
area should be capable of supporting emergency and maintenance equipment as well as providing support for aircraft.
The runway safety area is cleared, drained, and graded and
should have no potentially hazardous ruts, humps, depressions, or other surface variations. It should be free of objects
except for objects that are required to be located in the runway safety area because of their function. These objects are
required to be constructed on frangible mounted structures at
the lowest possible height with the frangible point no higher
than 3 in above grade.
5. The runway object-free area (OFA) is defined by the FAA as a
two-dimensional ground area surrounding the runway which
must be clear of parked aircraft and objects other than those
whose location is fixed by function.
6. The runway obstacle-free zone (OFZ) is a defined volume of
airspace centered above the runway which supports the transition between ground and airborne operations. The FAA specifies this as the airspace above a surface whose elevation is
the same as that of the nearest point on the runway centerline
and extending 200 ft beyond each end of the runway.
7. The inner approach obstacle-free zone, which applies only to
runways with approach lighting systems, is the airspace
above a surface centered on the extended runway centerline
beginning 200 ft beyond the runway threshold at the same
elevation as the runway threshold and extending 200 ft beyond
the last light unit on the approach lighting system. Its width
is the same as the runway obstacle-free zone and it slopes
upward at the rate of 50 horizontal to 1 vertical.
8. The inner transitional obstacle-free zone, which applies only to precision instrument runways, is defined by the FAA as the volume
of airspace along the sides of the runway and the inner approach
obstacle-free zone. The surface slopes at the rate of 3 horizontal
to 1 vertical out from the edge of the runway obstacle-free zone
and the inner approach obstacle-free zone until it reaches a height
of 150 ft above the established airport elevation.
9. The runway protection zone (RPZ) is an area on the ground
used to enhance the protection of people and objects near the
runway approach.
The FAA runway standards related to the pavement and shoulder
width, the safety area, the blast pad, and the obstacle-free surfaces are
given in Tables 6-7 and 6-8. Similar data for the ICAO are given in
Table 6-9.
203
204
Approach Type
Visual and Nonprecision Instrument, Airplane
Design Group
I
*
I
II
III
Precision Instrument, Airplane Design Group
*
IV
I
I
II
III
IV
Runway width
60
60
75
100
150
75
100
100
100
150
Shoulder width
10
10
10
20
25
10
10
10
20
25
Blast pad
Width
Length
80
60
80
100
95
150
140
200
200
200
95
60
120
100
120
150
140
200
200
200
Safety area
Width
Length†
120
240
120
240
150
300
300
600
500
1000
300
600
300
600
300
600
400
800
500
1000
Object-free area
Width
Length†
250
300
400
500
500
600
800
1000
800
1000
800
1000
800
1000
800
1000
800
1000
800
1000
Obstacle-free zone
Width‡
Length¶
120§
200
250
200
250
200
250
200
250
200
300
200
300
200
300
200
300
200
*
300
200
Facilities for small airplanes only.
From end of runway; with the declared distance concept, these lengths begin at the stop end of each ASDA and both ends of the LDA, whichever is
greater.
‡
For runways serving small aircraft only; for large aircraft the greater of 400 ft or 180 ft plus the wingspan of the most demanding aircraft plus 20 ft for
each 1000 ft of airport elevation.
§
For runways serving small aircraft with approach speeds of less than 50 kn; increase to 250 ft for runways serving aircraft with approach speeds greater
than 50 kn.
¶
Beyond the end of each runway.
†
TABLE 6-7
Runway Dimensional Standards, ft—Approach Category A and B Aircraft
Geometric Design of the Airfield
Airplane Design Group
I
II
III
IV
V
VI
100
100
100
a
150
150
200
10
10
20
a
25
35
40
120
100
120
150
140a
200
200
200
220
400
280
400
Safety area
Widthc
Lengthd
500
1000
500
1000
500
1000
500
1000
500
1000
500
1000
Object-free area
Width
Lengthd
800
1000
800
1000
800
1000
800
1000
800
1000
800
1000
400
200
400
200
400
200
400
200
400
200
400
200
Runway width
Shoulder width
b
Blast pad
Width
Length
Obstacle-free zone
Widthe
Lengthf
a
For airplane design group III serving aircraft with maximum certified takeoff weight
greater than 150,000 lb, the standard runway width is 150 ft, the shoulder width is 25 ft,
and the blast pad width is 200 ft.
b
Airplane design groups V and VI normally require stabilized or paved shoulder surfaces.
c
For Airport Reference Code C-I and C-II, a runway safety area width of 400 ft is permissible. For runways designed after 2/28/83 to serve aircraft approach category D aircraft, the runway safety area width increases 20 ft for each 1000 ft of airport elevation
above mean sea level.
d
From end of runway; with the declared distance concept, these lengths begin at the stop
end of each ASDA and both ends of the LDA, whichever is greater.
e
For large aircraft the greater of 400 ft or 180 ft plus the wingspan of the most demanding
aircraft plus 20 ft for each 1000 ft of airport elevation; for small aircraft 300 ft for precision instrument runways, 250 ft for all other runways serving small aircraft with
approach speeds of 50 kn or more, and 120 ft for all other runways serving small aircraft
with approach speeds less than 50 kn.
f
Beyond the end of each runway.
TABLE 6-8 Runway Dimensional Standards, ft—Approach Category C, D, and E
Aircraft
Parallel Runway System Spacing
The spacing of parallel runways depends on a number of factors such
as whether the operations are in VMC or IMC and, if in IMC, whether
it is desired to have the capability of accommodating simultaneous
arrivals or simultaneous arrivals and departures. At those airports
serving both heavy and light aircraft simultaneous use of runways
even in VMC conditions may be dictated by separation requirements
to safeguard against wake vortices.
205
206
Airport Design
Aerodrome Code Letter
A
B
C
D
E
1*
18
18
23
2*
23
23
30
3
30
30
30
45
45
45
45
60
60
60
Pavement width
Aerodrome code number
4
†,‡
Pavement and shoulder width
Aerodrome Code Number
1
2
3
4
Runway strip width
Precision approach
Nonprecision approach
Visual approach
150
150
60
150
150
80
300
300
150
300
300
150
Clear and graded area width‡
Instrument approach
Visual approach
80
60
80
80
150§
150
150§
150
‡
*
The width of a precision approach runway should not be less than 30 m where the aerodrome code number is 1 or 2.
†
Minimum width of pavement and shoulders when pavement width is less than 60 m.
‡
Symmetrical about the runway centerline.
§
It is recommended that this be provided for the first 150 m from each end of the runway and
that it should be increased linearly from this point to a width of 210 m at a point 300 m from
each end of the runway and remain at this width for the remainder of the runway.
TABLE 6-9
ICAO Runway and Runway Strip Dimensional Standards, m
Under VMC, the FAA requires parallel runway centerline separations of 700 ft for all aircraft when the operations are in the same direction and wake vortices are not prevalent. It also recommends increasing
the separation to 1200 ft for airplane design group V and VI runways. If
wake vortices are generated by heavy jets and it is desired to operate on
two runways simultaneously in VMC when little or no crosswind is
present, the minimum distance specified by the FAA is 2500 ft.
For operations under VMC, the ICAO recommends that the minimum separations between the centerlines of parallel runways for
simultaneous use disregarding wake vortices be 120 m (400 ft) for
aerodrome code number 1, 150 m (500 ft) for aerodrome code number
2, and 210 m (700 ft) for aerodrome code number 3 or 4 runways.
In IMC conditions, the FAA specifies 4300 ft and ICAO specifies
1525 m (5000 ft) as the minimum separation between centerlines of
Geometric Design of the Airfield
parallel runways for simultaneous instrument approaches. However,
there is evidence that these distances are conservative and steps are
being taken to reduce it. The ultimate goal is to reduce this distance
by about one-half. For dependent instrument approaches both the
FAA and ICAO recommend centerline separations of 3000 ft (915 m).
For triple and quadruple simultaneous instrument approaches, the
FAA requires 5000-ft separation between runway centerlines,
although will allow 4300 ft separations on a case-by-case basis.
Both the FAA and ICAO specify that two parallel runways may
be used simultaneously for radar departures in IMC if the centerlines
are separated by at least 2500 ft (760 m). The FAA requires a 3500-ft
centerline separation for simultaneous nonradar departures. If two
parallel runways are to be operated independently of each other in
IMC under radar control, one for arrivals and the other for departures, both the FAA and ICAO specify that the minimum separation
between the centerlines is 2500 ft (760 m) when the thresholds are
even. If the thresholds are staggered, the runways can be brought
closer together or must be separated farther depending on the amount
of the stagger and which runways are used for arrivals and departures. If approaches are to the nearest runway, then the spacing may
be reduced by 100 ft (30 m) for each 500 ft (150 m) of stagger down to
a minimum of 1200 ft (360 m) for airplane design groups V and VI
and 1000 ft (300 m) for all other aircraft. However, if the approaches
are to the farthest runway, then the runway spacing must be increased
by 100 ft (30 m) for each 500 ft (150 m) of stagger.
Sight Distance and Longitudinal Profile
The FAA requirement for sight distance on individual runways
requires that the runway profile permit any two points 5 ft above the
runway centerline to be mutually visible for the entire runway length.
If, however, the runway has a full length parallel taxiway, the runway
profile may be such that an unobstructed line of sight will exist from
any point 5 ft above the runway centerline to any other point 5 ft
above the runway centerline for one-half the runway length.
The FAA recommends a clear line of sight between the ends of
intersecting runways. The terrain must be graded and permanent
objects designed and sited so that there will be an unobstructed
line of sight from any point 5 ft above one runway centerline to
any point 5 ft above an intersecting runway centerline within the
runway visibility zone. The runway visibility zone is the area
formed by imaginary lines connecting the visibility points of the
two intersecting runways. The runway visibility zone for intersecting runways is shown in Fig. 6-21. The visibility points are
defined as follows:
1. If the distance from the intersection of the two runway centerlines is 750 ft or less, the visibility point is on the centerline
at the runway end designated by point a in Fig. 6-21.
207
Airport Design
2. If the distance from the intersection of the two runway centerlines is greater than 750 ft but less than 1500 ft, the visibility point is on the centerline 750 ft from the intersection of the
centerlines designated by point b in Fig. 6-21.
3. If the distance from the intersection of the two runway centerlines is equal to or greater than 1500 ft, the visibility point
is on the centerline equidistant from the runway end and the
intersection of the centerlines designated by points c and d in
Fig. 6-21.
The ICAO requirement for sight distance on individual runways
requires that the runway profile permit an unobstructed view
between any two points at a specified height above the runway centerline to be mutually visible for a distance equal to at least one-half
the runway length. ICAO specifies that the height of these two points
be 1.5 m (5 ft) above the runway for aerodrome code letter A runways, 2 m (7 ft) above the runway for aerodrome code letter B runways, and 3 m (10 ft) above the runway for aerodrome code letter C,
D, or E runways.
It is desirable to minimize longitudinal grade changes as much as
possible. However, it is recognized that this may not be possible for
reasons of economy. Therefore both the ICAO and FAA allow changes
A
a
x
d
WHEN
A ≤ 750' (225 m)
B < 1500' (450 m)
BUT > 750' (225 m)
C ≥ 1500' (450 m)
D ≥ 1500' (450 m)
750'
225 m
b
B
1
C
2
D
1
D
2
RUNWAY VISIBILITY
ZONE
C
208
c
THEN
xa = DISTANCE TO
END OF RUNWAY
xb = 750' (225 m)
xc = ½ C
xd = ½ D
FIGURE 6-21 Runway visibility zone for intersecting runways (Federal Aviation
Administration).
Geometric Design of the Airfield
Aircraft Approach Category
A
B
C
D
E
Pavement longitudinala
Maximum
Maximum change
2.0
2.0
2.0
2.0
1.5b
1.5
1.5b
1.5
1.5b
1.5
Pavement transverse
Maximum
2.0
2.0
1.5
1.5
1.5
Shoulder transverse
Minimum
Maximumd
3.0
5.0
3.0
5.0
1.5c
5.0
1.5c
5.0
1.5c
5.0
3.0
3.0
3.0
3.0
3.0
2.0
1.5
5.0
2.0
1.5
5.0
2.0
1.5
3.0
2.0
1.5
3.0
2.0
1.5
3.0
300g
250
300g
250
1000
1000
1000
1000
1000
1000
Gradient (%)
Runway end safety area
Maximum longitudinale
Maximum longitudinal
Grade change
Minimum transverse
Maximum transversed
Vertical curve (ft)
Minimum lengtha,f
Minimum distance between
points of intersectiona,h
a
Applies also to runway safety area adjacent to sides of the runway.
May not exceed 0.8 percent in the first and last quarter of runway.
c
A minimum of 3 percent for turf.
d
A slope of 5 percent is recommended for a 10 ft width adjacent to the pavement areas to
promote drainage.
e
For the first 200 ft from the end of the runway and if it slopes it must be downward. For
the remainder of the runway safety area the slope must be such that any upward slope
does not penetrate the approach surface or clearway plane and any downward slope
does not exceed 5 percent.
f
For each 1 percent change in grade.
g
No vertical curve is required if the grade change is less than 0.4 percent.
h
Distance is multiplied by the sum of the absolute grade grade changes in percent.
Source: Federal Aviation Administration [6].
b
TABLE 6-10
Runway Surface Gradient Standards
in grade but limit their number and size. The maximum longitudinal
grade changes that are permitted by the FAA are listed in Table 6-10
and illustrated in Fig. 6-22. The maximum longitudinal grade changes
that are permitted by the ICAO are listed in Table 6-11. Tables 6-10 and
6-11 also list the maximum longitudinal grade. The FAA limits both
209
210
Airport Design
Profile of runway centerline
0 to 2%
0 to
2%
Grade
change
0 to
Vertical
curve
length
2%
Vertical
curve length
Grade
change
0 to
2%
Distance between
change in grade
(a)
200'
1
runway
4
End
Grade
change
–3%
0 to 1.5
%
End of runway
Grade
change
Vertical
curve
length
0 to 0.8%
Vertical
curve
length
%
0 to 1.5
1.5% max
Grade
change
Distance
between
change in
grade
1
runway
4
Distance
between
change
in grade
Vertical
curve
length
0 to 0.8% 0 to
–
3%
End of runway
End
0 to
200'
Profile of runway centerline
(b)
FIGURE 6-22
Runway longitudinal profile: (a) utility airports, (b) transport airports.
longitudinal gradient and longitudinal grade changes to 2 percent for
runways serving approach category A and B aircraft and 1.5 percent
for runways serving approach category C, D, and E aircraft. ICAO
limits both longitudinal gradient and longitudinal grade changes to
2 percent for aerodrome code number 1 and 2 runways and 1.5 percent
for aerodrome code number 3 runways. For aerodrome code number
4 runways the maximum longitudinal gradient is 1.25 percent and the
Geometric Design of the Airfield
maximum change in longitudinal gradient is 1.5 percent. In addition,
for runways that are equipped to be used in bad weather, the gradient
of the first and last quarter of the length of the runway must be very
flat for reasons of safety. Both the ICAO and the FAA require that this
gradient not exceed 0.8 percent. In all cases it is desirable to keep both
longitudinal grades and grade changes to a minimum.
Longitudinal slope changes are accomplished by means of vertical
curves. The length of a vertical curve is determined by the magnitude of
the changes in slope and the maximum allowable change in the slope of
the runway. Both these values are also listed in Tables 6-11 and 6-12.
Aerodrome Code Number
Runway longitudinal
Gradient (%)
Maximum
Maximum change
Maximum effective†
Vertical curve (m)
Minimum length of curve‡
Minimum distance between
points of intersection§
Runway strips
Gradient (%)
Maximum longitudinal
Maximum transverse
1
2
3
4
2.0
2.0
2.0
2.0
2.0
2.0
1.5*
1.5
1.0
1.25*
1.5
1.0
75
50
150
50
300
150
300
300
2.0
3.0
2.0
3.0
1.75
2.5
1.5
2.5
Aerodrome Code Letter
A
B
C
D
E
Runway transverse gradient (%)
Maximum
Minimum
2.0
1.0
2.0
1.0
1.5
1.0
1.5
1.0
1.5
1.0
Shoulder transverse gradient (%)
Maximum
2.5
2.5
2.5
2.5
2.5
*
May not exceed 0.8 percent in the first and last quarter of runway for aerodrome code
number 4 or for a category II or III precision instrument runway for aerodrome code
number 3.
†
Difference in elevation between high and low point divided by runway length
‡
For each 1 percent change in grade.
§
Distance is multiplied by sum of absolute grade changes in percent minimum length is 45 m.
Source: International Civil Aviation Organization [3].
TABLE 6-11
Runway Surface Gradient Standards
211
212
Airport Design
Airplane Design Group
I
*
I
II
III
IV
Visual or nonprecision runway
centerline to
Taxiway or taxilane centerline†
Hold line†
Helicopter touchdown pad
Aircraft parking area
150
125
400
125
225
200
400
200
240
200
400
250
300
200
400
400
400
250
400
500
Precision instrument runway
centerline to
Taxiway or taxilane centerline†
Hold line†
Helicopter touchdown pad
Aircraft parking area
200
175
400
400
250
250
400
400
300
250
400
400
350
250‡
400
400
400
250‡
400
500
*
For facilities for small aircraft only.
Satisfies the requirement that no part of an aircraft at a holding an increase to these
separations may be needed to achieve this result.
‡
For sea level up to elevation 6000 ft. Increase by 1 ft for each 100 ft of airport elevation
above 6000 ft.
Source: Federal Aviation Administration [6].
†
TABLE 6-12 Airfield Separation Criteria for Aircraft in Approach Categories A and
B, ft
The number of slope changes along the runway is also limited.
The FAA requires that the distance between the points of intersection
of two successive curves should not be less than the sum of the absolute percentage values of change in slope multiplied by the 250 ft for
airports serving aircraft approach category A and B aircraft and 1000 ft
for airports serving aircraft approach category C, D, and E aircraft.
The ICAO requires that the distance between the points of intersection of two successive curves should not be less than the sum of the
absolute percentage values of change in slope multiplied by 50 m
(165 ft) for aerodrome code number 1 and 2 runways, 150 m (500 ft)
for aerodrome code number 3 runways, and 300 m (1000 ft) for aerodrome code number 4 runways. ICAO also specifies that the minimum distance in all cases is 45 m (150 ft).
For example, for an FAA runway serving transport aircraft, that is,
approach category C, D, or E aircraft, if the change in slope was 1.5
percent, the required length of vertical curve would be 1500 ft. Vertical
curves are normally not necessary if the change in slope is not more
than 0.4 percent. The FAA specifies a minimum length of vertical transition curve of 300 for each 1 percent change in grade for runways
Geometric Design of the Airfield
10'
5%
ment
y pave
Runwa
11''
2
Detail A
CL
Runway safety area
Shoulder
Detail A
Obstacle-free
area slope
Structural
pavement
1
3
Obstacle-free
area width
FIGURE 6-23 Runway gradient cross section.
serving approach category A and B aircraft and 1000 ft for each 1 percent
change in grade for airport serving approach category C, D, and E
aircraft. ICAO specifies a minimum length of vertical transition curve
of 75 m for each 1 percent change in grade for aerodrome code number
1 runways, 150 m for each 1 percent change in grade aerodrome code
number 2 runways, and 300 m for each 1 percent change in grade for
aerodrome code number 4 runways.
Transverse Gradient
A typical cross section of a runway is shown in Fig. 6-23. The FAA
and ICAO specifications for transverse slope on the runways are
given in Tables 6-10 and 6-11, respectively. It is recommended that a
5 percent transverse slope be provided for the first 10 ft of shoulder
adjacent to a pavement edge to ensure proper drainage.
Airfield Separation Requirements Related to Runways
The minimum distance from the runway centerline to parallel taxiways, taxilanes, aircraft holding lines, helicopter touchdown pads,
and aircraft parking areas are also specified. These distances are given
in Tables 6-12 and 6-13 for the FAA and Tables 6-14 and 6-15 for
ICAO.
Obstacle Clearance Requirements
In addition to the geometric standards associated with the design of
runways, there are specific requirements concerning the protection of
airspace around airfields to provide for the safe navigation of aircraft
to and from the airport.
In the United States, the FAA requires that protection zones be
provided at the ends of runways. The runway protection zone is the
area on the ground beneath the approach surface to a runway from the
end of the primary surface to the point where the approach surface is
50 ft above the primary surface, as shown in Fig. 6-24. The dimensions
of the runway protection zone are provided in Table 6-16.
213
214
Airport Design
Airplane Design Group
I
II
III
IV
V
VI
300
300
400
400
400¶
600
Hold line*
250
250
250
250
250
250
Helicopter touchdown
pad
Aircraft parking area
400
400
400
400
400
400
400
400
500
500
500
500
400
400
400
400
400¶
600
250
400
250
400
250†
400
250†
400
280‡
400
325
400
500
500
500
500
500
500
Visual or nonprecision
runway
Centerline to
Taxiway or taxilane
centerline*
Precision instrument
runway
Centerline to
Taxiway or taxilane
centerline*
Hold line*,§
Helicopter touchdown
pad
Aircraft parking area
*
Satisfies the requirement that no part of an aircraft at a holding location or on a taxiway
centerline is within the runway safety area or penetrates the obstacle free zone. Accordingly, at higher elevations an increase to these separations may be needed to achieve
this result.
†
For aircraft in aircraft approach category C and airplane design groups III and IV increase
by 1 ft for each 100 ft of airport elevation greater than 3200 ft.
‡
For aircraft in aircraft approach category C and airplane design group V increase by 1 ft
for each 100 ft of airport elevation above mean sea level.
§
For aircraft in aircraft approach category D increase by 1 ft for each 100 ft of airport elevation above mean sea level.
¶
For airports at or below an elevation of 1345 ft; increase to 450 ft for airports at elevations
between 1345 and 6560 ft and to 500 ft for airports at an elevation above 6560 ft.
Source: Federal Aviation Administration [6].
TABLE 6-13 Airfield Separation Criteria for Aircraft in Approach Categories C and
D, ft
When the runway protection zone begins at a location other than
200 ft beyond the end of the runway due to the application of the
declared distance concept discussed in Chap. 2, two runway protection zones are usually required, an approach runway protection zone
and a departure runway protection zone. The dimensions of the
approach runway protection zone are given in Table 6-16 but the
departure runway protection zone begins 200 ft beyond the far end of
Geometric Design of the Airfield
Aerodrome Code Letter
A
B
37.5
47.5
42
52
C
D
E
93
101
101
107.5
176
176
182.5
Runway centerline to parallel
taxiway centerline
Noninstrument runways
Aerodrome code 1
Aerodrome code 2
Aerodrome code 3
Aerodrome code 4
Instrument runways
Aerodrome code 1
Aerodrome code 2
Aerodrome code 3
Aerodrome code 4
82.5
82.5
87
87
168
Source: International Civil Aviation Organization [2, 3, 4].
TABLE 6-14
Runway to Taxiway Separation Criteria on the Airfield, m
Type of Runway
Noninstrument
Aerodrome code 1
Aerodrome code 2
Aerodrome code 3
Aerodrome code 4
30
40
75
75
Nonprecision
Approach
40
40
75
75
Precision
Approach
Category
I
II & III
Takeoff
60
*
−
30
60
*
−
90
*,†
*,†
90
40
*,†
75
*,†
75
90
90
*
This distance may have to be increased to avoid interference with radio aids; for a precision instrument category III runway this increase may be in the order of 50 m.
†
If a holding bay or a taxiway holding position is at a lower elevation compared to the
runway threshold the distance may be decreased by 5 m for every meter the holding
bay or holding position is lower than the threshold, contingent upon not interfering
with the inner transitional surface; if a holding bay or a taxiway holding position is
at a higher elevation compared to the runway threshold the distance should be
increased by 5 m for every meter the holding bay or holding position is higher than
the threshold.
Source: International Civil Aviation Organization [2, 3, 4].
TABLE 6-15
Runway to Holding Line Separation Criteria on the Airfield, m
215
216
Airport Design
50'
V
H
L
200'
CL
W1
W2
FIGURE 6-24 Runway protection zone.
the takeoff run available and the portion of the runway between the
takeoff run available and the end of the runway is declared unavailable and unsuitable for the takeoff run. The dimensions of the departure runway protection zone are
1. For runways serving only small aircraft in aircraft approach
categories A and B, the length is 1000 ft, the inner width is 250 ft
and the outer width is 450 ft.
2. For runways serving large aircraft in aircraft approach categories A and B, the length is 1000 ft, the inner width is 500 ft
and the outer width is 700 ft.
3. For runways serving aircraft in aircraft approach categories
C, D, or E, the length is 1700 ft, the inner width is 500 ft and
the outer width is 1010 ft.
FAR Part 77
Part 77 of the Federal Aviation Regulations establishes standards for
determining what would be considered obstructions to navigable airspace, sets forth the requirements for notice to the FAA due to certain
proposed construction or alteration activities, and provides for aeronautical studies of obstructions to air navigation to determine the effect
of these obstructions on the safe and efficient use of airspace [8, 9]. The
airport operator has the responsibility to ensure that the aerial
approaches to the airport will be adequately cleared and protected
and that the land adjacent to or in the immediate vicinity of the airport
Geometric Design of the Airfield
Width
Aircraft
Served
Runway
Approach
End
Approach*
Opposite
End
Length
L, ft
Small
V
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
V
NP
NP+
P
1000
1000
1000
1000
1000
1000
1000
1000
1700
1700
1700
1700
2500
2500
2500
2500
1000
1000
1000
1000
1700
1700
1700
1700
1700
1700
1700
1700
2500
2500
2500
2500
NP
NP+
P
Large
V
NP
NP+
P
Inner
W1, ft
250
500
1000
1000
500
500
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
500
500
1000
1000
500
500
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
Outer
W2, ft
450
650
1050
1050
800
800
1200
1200
1510
1510
1510
1510
1750
1750
1750
1750
700
700
1100
1100
1010
1010
1425
1425
1510
1510
1510
1510
1750
1750
1750
1750
Area,
acres
8.035
13.200
23.542
23.542
14.922
14.922
25.252
25.252
48.978
48.978
48.978
48.978
78.914
78.914
78.914
78.914
13.770
13.770
24.105
24.105
29.465
29.465
47.320
47.320
48.978
48.978
48.978
48.978
78.914
78.914
78.914
78.914
V = visual approach; NP = nonprecision instrument approach with visibility minimums
more than ¾ statute mile; NP+ = nonprecision instrument approach with visibility minimums as low as ¾ statute mile; P = precision instrument approach.
Source: Federal Aviation Administration [5].
∗
TABLE 6-16
Runway Protection Zone Dimensions
217
218
Airport Design
is reasonably restricted to the extent possible through the use of such
measures as the adoption of zoning ordinances. A model zoning ordinance to limit the height of objects around airports is published by
the FAA [6].
Subpart C of FAR Part 77 establishes standards for determining
obstructions to air navigation. The standards apply to existing and
man-made objects, objects of natural growth, and terrain.
In order to determine whether an object is an obstruction to air
navigation, several imaginary surfaces are established with relation to the airport and to each end of a runway. The size of the
imaginary surfaces depends on the category of each runway (e.g.,
utility or transport) and on the type of approach planned for that
end of the runway (e.g., visual, nonprecision instrument, or precision instrument).
The principal imaginary surfaces are shown in Fig. 6-25. They are
described as follows:
1. Primary surface. The primary surface is a surface longitudinally centered on a runway. When the runway is paved, the
primary surface extends 200 ft beyond each end of the runway. When the runway is unpaved, the primary surface coincides with each end of the runway. The elevation of the primary surface is the same as the elevation of the nearest point
on the runway centerline.
2. Horizontal surface. The horizontal surface is a horizontal
plane 150 ft above the established airport elevation, the
perimeter of which is constructed by swinging arcs of specified radii from the center of each end of the primary surface
of each runway and connecting each arcs by lines tangent to
those arcs.
3. Conical surface. The conical surface is a surface extending outward and upward from the periphery of the horizontal surface at a slope of 20 horizontal to 1 vertical for a horizontal
distance of 4000 ft.
4. Approach surface. The approach surface is a surface longitudinally centered on the extended runway centerline and extending
outward and upward from each end of a runway at a designated slope based upon the type of available or planned
approach to the runway.
5. Transitional surface. Transitional surfaces extend outward and
upward at right angles to the runway centerline plus the runway centerline extended at a slope of 7 to 1 from the sides of
the primary surface up to the horizontal surface and from the
sides of the approach surfaces. The width of the transitional
surface provided from each edge of the approach surface is
5000 ft.
A
7:1
4,000
7:1
7:1
A
40:1
7:1
5,000
7:1
A
16,000
7:1
40:1
FIGURE 6-25 FAR part 77 imaginary surfaces.
D
E
7:1
B
5,000
C
50:1
7:1
7:1
7:1
7:1
7:1
7:1
7:1
E
HORIZONTAL SURFACE
150 FEET ABOVE
ESTABLISHED AIRPORT
ELEVATION
20-1 CONICAL SURFACE
219
220
Airport Design
OBSTRUCTION IDENTIFICATION SURFACES
FEDERAL AVIATION REGULATIONS PART 77
DIMENSIONAL STANDARDS (FEET)
DIM
ITEM
VISUAL
RUNWAY
NON - PRECISION
INSTRUMENT
RUNWAY
A
B
A
A
WIDTH OF PRIMARY SURFACE AND APPROACH SURFACE WIDTH
AT INNER END
250
500
500
B
RADIUS OF HORIZONTAL SURFACE
5,000
5,000
VISUAL
APPROACH
B
C
D
500
1,000
1,000
10,000
10,000
5,000 10,000
NON - PRECISION
INSTRUMENT
APPROACH
A
PRECISION
INSTRUMENT
RUNWAY
B
PRECISION
INSTRUMENT
APPROACH
A
B
C
D
C
APPROACH SURFACE WIDTH AT END
1,250
1,500
2,000
3,500
4,000
16,000
D
APPROACH SURFACE LENGTH
5,000
5,000
5,000 10,000
10,000
*
E
APPROACH SLOPE
20:1
20:1
20:1
34:1
*
34:1
• A - UTILITY RUNWAYS
• B - RUNWAYS LARGER THAN UTILITY
• C - VISIBILITY MINIMUMS GREATER THAN 3/4 MILE
• D - VISIBILITY MINIMUMS AS LOW AS 3/4 MILE
• * - PRECISION INSTRUMENT APPROACH SLOPE IS 50:1 FOR INNER 10,000 FEET AND 40:1 FOR AN ADDITIONAL 40,000 FEET
FIGURE 6-26
Part 77 Imaginary Surface Dimensions, ft.
Dimensions of the several imaginary surfaces are shown in
Fig. 6-26.
In addition to the surfaces defined earlier, other standards for
determining obstructions to air navigation are contained in FAR
Part 77. Existing and future objects, whether stationary or mobile, are
considered to be obstructions to air navigation if they are of greater
height than any of the following heights or surfaces:
1. A height of 500 ft above ground level at the site of the object.
2. A height that is 200 ft above ground level or 200 ft above
the established airport elevation, whichever is greater, within
3 nautical miles of the established reference point at an airport with its longest runway more than 3200 ft in actual
length. This height increases in the ratio of 100 ft for each
additional nautical mile of distance from the reference point
up to a maximum of 500 ft.
3. A height within a terminal obstacle clearance area, including
an initial approach segment, a departure area, and a circling
approach area, which would result in the vertical distance
between any point on the object and an established minimum
instrument flight altitude within that area or segment to be
less than the required obstacle clearance.
4. A height within an en route obstacle clearance area, including
turn and termination areas, of a federal airway or approved
off-airway route, that would increase the minimum obstacle
clearance altitude.
5. The surface of a takeoff and landing area of an airport or any
of the imaginary surfaces defined earlier.
Geometric Design of the Airfield
6. Except for traverse ways on or near an airport with an operative ground traffic control service furnished by the air traffic
control tower or by airport management and coordinated
with the air traffic control service, the heights of traverse
ways must be increased by 17 ft for interstate highways, 15 ft
for any other public roadway, 10 ft or the height of the highest
mobile object that would normally traverse the road, whichever is greater, for a private road, 23 ft or an amount equal to
the height of the highest mobile object that would normally
traverse it for railroads, waterways, or any other thoroughfare not previously mentioned.
Subpart B of FAR Part 77 identifies circumstances where notice is
required to be given to the FAA when certain construction or alteration activities are proposed. These include the circumstances associated with the standards given above and also any construction or
alteration of greater height than an imaginary surface extending outward and upward at one of the following slopes [9]:
1. A slope of 100 horizontal to 1 vertical for a horizontal distance of 20,000 ft from the nearest point of the nearest runway
at an airport or seaplane base with at least one runway more
than 3200 ft in actual length.
2. A slope of 50 horizontal to 1 vertical for a horizontal distance
of 10,000 ft from the nearest point of the nearest runway at an
airport or seaplane base with its longest runway no more
than 3200 ft in actual length.
3. A slope of 25 horizontal to 1 vertical for a horizontal distance
of 5000 ft from the nearest point of the nearest takeoff and
landing area for a heliport.
FAR Part 77 imposes strict requirements on both airport sponsors
and others associated with construction activities in the vicinity of
airports which should be referenced prior to initiating construction
activities.
ICAO Annex 14
The ICAO requirements are similar to FAR Part 77 with the following
exceptions. ICAO separates arrivals and departures and specifies
dimensions for approach surfaces and takeoff climb surfaces for
departures. The horizontal surface specified by ICAO is a circle whose
center is at the airport reference point, whereas in FAR Part 77 it is not a
circle nor is the airport reference point used to determine the horizontal surface. The airport reference point is the geometric centroid of the
runway system at the airport based upon the lengths of the runways.
The height of this surface is 150 ft above the airport elevation, the
same as in Part 77. In FAR Part 77 the conical surface extends horizontally 4000 ft at a slope of 20 to 1 irrespective of the type of runway and
221
222
Airport Design
visibility. In ICAO Annex 14 [1, 2, 3] the slope of the conical surface is
the same, but the horizontal distance varies depending upon the
aerodrome reference code.
In FAR Part 77 the slope of the transitional surface is a constant 7
to 1, whereas in ICAO Annex 14 this slope is specified for runway
reference codes 3 and 4. For other runways the slope is 5 to 1.
TERPS
As defined in FAA Order 8260.3b, TERPS (which stands for terminal
instrument approach procedures) is a compilation of criteria used to
design published standard procedures for aircraft using instrumentbased navigation to depart and approach to airport facilities. These
procedures are designed based primarily on the performance characteristics of aircraft, the various types of instrument navigational aids
that may be present at or around an airport, and currently existing
natural and man-made objects surrounding the airport. As part of
these procedures, minimum climb-out gradients for aircraft departures, and minimum descent gradients and safe operating altitudes
for aircraft approaches are defined. While TERPS contain standards
for creating such procedures, for any given runway at any given airport, one or more approach and departure procedures may be defined,
each of which may be entirely unique, based on the airport environment.
With respect to airport design, TERPS defines a “required obstacle clearance” (ROC) value. For aircraft operating within the airport
environment, this value is typically as low as 250 ft above the highest
object near the runway. The required obstacle clearance values for a
published procedure in turn define the TERPS obstacle clearance surface (OCS), as illustrated in Fig. 6-27. The typical slopes for obstacle
clearance surfaces for aircraft on approach is on the order of 318 ft/nmi
and for departures approximately 200 ft/nmi.
A typical TERPS procedure consists of a series of segments,
including climb, en route, initial approach, intermediate approach,
final approach, and missed approach segments, that are created based
ROC
h
pat
de
Gli
OCS
ASBL
FIGURE 6-27 TERPS obstacle clearance surface.
Geometric Design of the Airfield
OBSTACLE
INITIAL
INTERMEDIATE
FINAL
RUNWAY
MISSED APPROACH RE-ENTER ENROUTE
PHASE
PLAN
FLIGH
1000'
500'
T PAT
H
MAP
1000'
PROFILE
PROJECTED VIEW
FIGURE 6-28
Typical TERPS procedure segments.
on the above standards and the existing terrain and obstacle environment for any given runway, as illustrated in Fig. 6-28.
It is widely understood that protecting airspace for TERPS is a
complex process, often unique to each airport. For planning purposes,
however, a slope with 40:1 gradient and 15° from the runway end
should be considered as TERPS obstacle clearance surface criteria.
Runways with the intention of being supported by published instrument procedures should be designed in such a manner to avoid any
natural or man-made obstacles that penetrate this surface. Once a
runway exists, airport planners should work to ensure that future
development does not conflict with TERPS or FAR Part 77 obstacle
clearance requirements.
Runway End Siting Requirements
The specifications for determining obstacles to safe air navigation
to existing runways are described in FAR Part 77 and TERPS procedures. However, when locating, or siting a runway, the FAA prescribes a different, yet complimentary set of specifications. These
specifications are published in Appendix 2 of Advisory Circular AC
150/5300-13, identified in Table 6-17, and illustrated in Figs. 6-29
through 6-31.
223
224
Slope/
OCS
Dimensional Standards*, ft
Runway Type
A
B
C
D
E
1
Approach end of runways expected to serve small airplanes
with approach speeds less than 50 kn (visual runways only,
day/night)
0
60
150
500
2,500
15:1
2
Approach end of runways expected to serve small airplanes
with approach speeds of 50 kn or more (visual runways only,
day/night)
0
125
350
2,250
2,750
20:01
3
Approach end of runways expected to serve large airplanes
(visual day/night); or instrument minimums ≥ 1 statute mile (day
only)
0
200
500
1,500
8,500
20:1
4
Approach end of runways expected to support instrument night
circlinga
200
200
1,700
10,000
0
20:1
5
Approach end of runways expected to support instrument straight
in night operations. Serving approach category A and B aircraft
only.a
200
200
1,900
10,000b
0
20:1
6
Approach end of runways expected to support instrument straight
in night operations serving greater than approach category B
aircraft.a
200
400
1,900
10,000b
0
20:1
7e,f,g,h
Approach end of runways expected to accommodate approaches
with positive vertical guidance (GQS)
0
760
10,000b
0
30:1
8
Approach end of runways expected to accommodate instrument
approaches having visibility minimums ≥ ¾ but < 1 statute mile,
day or night
200
1,900
10,000b
0
20:1
½
width
runway
+100
400
9
Approach end of runways expected to accommodate instrument
approaches having visibility minimums < ¾ statute mile or
precision approach (ILS, GLS, or MLS) day or night
10
Approach runway ends having category II approach minimums or
greater
11
Departure runway ends for all instrument operations
12
Departure runway ends supporting air carrier operations
c
∗
200
400
1,900
10,000b
0
34:1
The criteria are set forth in TERPS. Order 8260.3.
0d
See Fig. 6-30
40:1
0
See Fig. 6-31
625:1
d
225
Dimensional standards illustrated in Fig. 6-29
Notes:
a
Lighting of obstacle penetrations to this surface or the use of a VGSI, as defined by the TERPS order, may avoid displacing the threshold.
b
10,000 ft is a nominal value for planning purposes. The actual length of these areas is dependent upon the visual descent point position for 20:1 and
34:1 and decision altitude point for the 30:1.
c
Any penetration to this surface will limit the runway end to nonprecision approaches. No vertical approaches will be authorized until the penetration(s)
is/are removed except obstacles fixed by function and/or allowable grading.
d
Dimension A is measured relative to departure end of runway (DER) or TODA (to include clearway).
e
Data collected regarding penetrations to this surface are provided for information and use by the air carriers operating from the airport. These requirements do not take effect until January 1, 2009.
f
Surface dimensions/obstacle clearance surface (OCS) slope represent a nominal approach with 3° GPA, 50′ TCH, < 500′ HAT. For specific cases refer to
TERPS. The obstacle clearance surface slope (30:1) represents a nominal approach of 3° (also known as the glide path angle). This assumes a threshold
crossing height of 50 ft. Three degrees is commonly used for ILS systems and VGSI aiming angles. This approximates a 30:1 approach angle that is
between the 34:1 and the 20:1 notice surfaces of Part 77. Surfaces cleared to 34:1 should accommodate a 30:1 approach without any obstacle clearance
problems.
g
For runways with vertically guided approaches the criteria in Row 7 is in addition to the basic criteria established within the table, to ensure the protection of the glide path qualification surface.
h
For planning purposes, sponsors and consultants determine a tentative decision altitude based on a 3° glide path angle and a 50-ft threshold crossing
height.
TABLE 6-17
Runway End Siting Requirements Dimensions Table
226
Airport Design
D
E
THRESHOLD
2B
2C
A
OBJECT
THRESHOLD
SLOPE
OBJECT
A
FIGURE 6-29 Runway end siting requirements.
These specifications are used to site the location of a runway’s
threshold so that approach and departure procedures associated with
that runway are not adversely affected by existing obstacles or terrain. The siting specifications vary depending on a number of runway use conditions, including
SURFACE STARTS
AT END OF CLEAR
WAY IF ONE IS IN
PLACE
15°
3,233 FEET
1,000 FEET
500 FEET
TERPS (40:1)
15°
3,233 FEET
10,200 FEET
STARTS AT
DEPARTURE END
OF RUNWAY (DER)
OR END OF THE
CLEARWAY
(IF ONE EXISTS)
Clearway
Slope
80:1 or 1.25%
)
40:1
PS (
TER
)
40:1
PS (
TER
SEE
NOTE 1
SURFACE STARTS AT THE ELEVATION OF THE CLEARWAY
SURFACE (IF ONE EXISTS)
10,200 FEET
NOTES:
1. THIS IS AN INTERPRETATION OF THE APPLICATION OF THE TERPS SURFACE
ASSOCIATED WITH A CLEARWAY.
FIGURE 6-30 TERPS departure obstacle identification surfaces.
Geometric Design of the Airfield
OIS SURFACE
STARTS AT END
OF CLEARWAY
IF ONE IS IN PLACE
6,000 FEET
15°
600 FEET
300 FEET
CL
20
L
300 FEET
15°
OBSTACLE IDENTIFICATION
SURFACE (OIS)
62.5:1
6,000 FEET
50,000 FEET
STARTS AT
DEPARTURE END
OF RUNWAY (DER)
OR END OF
CLEARWAY
(IF ONE EXISTS)
OIS
OIS
Clearway
Slope
80:1 or 1.25%
FIGURE 6-31
:1)
(62.5
:1)
(62.5
SURFACE STARTS AT THE ELEVATION OF
THE CLEARWAY SURFACE (IF ONE EXISTS)
50,000 FEET
One engine inoperative obstacle identification surface (62.5:1).
• The approach speed of arriving aircraft
• The approach category of arriving aircraft
• Day versus night operations
• Types of instrument approaches
• The presence of published instrument departure procedures
• The use of the runway by air carriers
Runway end siting requirements are often the most confusing as
well as overlooked element of runway planning. Care should be
given to fully understand the purpose of the planned runway, the
type of aircraft that will be using the runway, the current and future
instrument approach procedures associated with the runway, and of
course any terrain or obstacles in the vicinity.
Should an object penetrate any of the surfaces at the site of a
runway, the airport planner has the option of displacing the runway threshold, as illustrated in Fig. 6-32. Displacing the threshold
allows the airport planner to design runways with sufficient
lengths to accommodate aircraft departures, while also allowing
arrivals to safely approach the runway by maintaining sufficient
clearance from upstream obstacles. Displacing the threshold does
carry the penalty of reducing available runway lengths for landing. The FAA recommends avoiding the need for displaced thresholds when possible, but recognizes their benefits in the wake of no
other alternatives.
227
228
Airport Design
D
E
DISPLACED THRESHOLD
2B
2C
A
FIXED OBJECT
RUNWAY END
DISPLACED THRESHOLD
SLOPE
FIXED OBJECT
A
RUNWAY END
DISPLACEMENT NECESSARY
FIGURE 6-32
Use of displaced threshold, runway siting requirements.
Taxiways and Taxilanes
Taxiways are defined paths on the airfield surface which are established for the taxiing of aircraft and are intended to provide a linkage
between one part of the airfield and another. The term “dual parallel
taxiways” refers to two taxiways parallel to each other on which airplanes can taxi in opposite directions. An apron taxiway is a taxiway
located usually on the periphery of an apron intended to provide a
through taxi route across the apron. A taxilane is a portion of the aircraft parking area used for access between the taxiways and the aircraft
parking positions. ICAO defines an aircraft stand taxilane as a portion
of the apron intended to provide access to the aircraft stands only.
In order to provide a margin of safety in the airport operating
areas, the trafficways must be separated sufficiently from each other
and from adjacent obstructions. Minimum separations between the
centerlines of taxiways, between the centerlines of taxiways and taxilanes, and between taxiways and taxilanes and objects are specified
in order that aircraft may safely maneuver on the airfield.
Widths and Slopes
Since the speeds of aircraft on taxiways are considerably less than on
runways, criteria governing longitudinal slopes, vertical curves, and
sight distance are not as stringent as for runways. Also the lower
speeds permit the width of the taxiway to be less than that of the
runway. The principal geometric design features of interest are listed
in Tables 6-18 and 6-19 for the FAA. ICAO standards are listed in
Tables 6-20 and 6-21.
Geometric Design of the Airfield
Airplane Design Group
I
Width
II
25
35
50
10
c
75
V
75
VI
100
15
15
20
10
10
20
25
35d
40d
Safety area widthe
49
79
118
171
214
262
89
131
186
259
320
386
79
115
162
225
276
334
Taxiway centerline to
taxiway centerlineh
fixed or movable
objecti
69
44.5
105
62.5
152
93
215
129.5
267
160
324
193
Taxilane centerline to
taxilane centerlinej
fixed or movable
objectk
64
39.5
97
57.5
140
81
198
112.5
245
138
298
167
Edge safety margin
7.5
IV
a
Shoulder width
b
5
III
Object-free area width
Taxiwayf
Taxilane
g
Separations
a
For airplanes in airplane design group III with a wheelbase equal to or greater than 60 ft,
the standard taxiway width is 60 ft.
b
The taxiway edge safety margin is the minimum acceptable between the outside of the
airplane wheels and the pavement edge.
c
For airplanes in airplane design group III with a wheelbase equal or greater than 60 ft,
the taxiway edge safety margin is 15 ft.
d
Airplanes in airplane design groups V and VI normally stabilized or paved taxiway
shoulder surfaces.
e
May use aircraft wingspan in lieu of these values.
f
May use 1.4 wingspan plus 20 ft in lieu of these values.
g
May use 1.2 wingspan plus 20 ft in lieu of these values.
h
May use 1.2 wingspan plus 10 ft in lieu of these values.
i
May use 0.7 wingspan plus 10 ft in lieu of these values.
j
May use 1.1 wingspan plus 10 ft in lieu of these values.
k
May use 0.6 wingspan plus 10 ft in lieu of these values.
Source: Federal Aviation Administration [6].
TABLE 6-18
Taxiway Dimensional Standards, ft
Taxiway and Taxilane Separation Requirements
FAA Separation Criteria
The separation criteria adopted by the FAA are predicated upon the
wingtips of the aircraft for which the taxiway and taxilane system
have been designed and provide a minimum wingtip clearance on
229
230
Airport Design
Aircraft Approach Category
A
B
C
D
E
Maximum
2.0
2.0
1.5
1.5
1.5
Maximum change
3.0
3.0
3.0
3.0
3.0
Minimum
1.0
1.0
1.0
1.0
1.0
Maximum
2.0
2.0
1.5
1.5
1.5
Minimum
3.0
3.0
1.5*
1.5*
1.5*
Maximum†
5.0
5.0
5.0
5.0
5.0
Minimum
3.0
3.0
1.5
1.5
1.5
Maximum
5.0
5.0
3.0
3.0
3.0
Minimum length‡
100
100
100
100
100
Minimum distance between
points of intersection§
100
100
100
100
100
Gradient (%)
Taxiway, shoulder and safety area
Longitudinal
Taxiway transverse
Shoulder transverse
Safety area transverse
Vertical curve (ft)
*
A minimum of 3 percent for turf.
A slope of 5 percent is recommended for a 10-ft width adjacent to the pavement areas to
promote drainage.
‡
For each 1 percent of grade change.
§
Distance is multiplied by the sum of the absolute grade changes in percent.
Source: Federal Aviation Administration [6].
†
TABLE 6-19
Taxiway Gradient Standards
these facilities. The required separation between taxiways, between a
taxiway and a taxilane, or between a taxiway and a fixed or movable
object requires a minimum wingtip clearance of 0.2 times the wingspan of the most demanding aircraft in the airplane design group
plus 10 ft. This clearance provides a minimum taxiway centerline to a
parallel taxiway centerline or taxilane centerline separation of 1.2
times the wingspan of the most demanding aircraft plus 10 ft, and
between a taxiway centerline and a fixed or movable object of 0.7
times the wingspan of the most demanding aircraft plus 10 ft. This
Geometric Design of the Airfield
Aerodrome Code Letter
A
B
C
D
E
15*
18†
23
25
38
44
Width
Pavement
7.5
10.5
Pavement and shoulder
Edge safety margin, U1
1.5
2.25
3‡
4.5
4.5
Strip
27
39
57
85
93
Graded portion of strip
22
25
25
38
44
Minimum separation
Taxiway centerline to taxiway centerline
21
31.5
46.5
68.5
81.5
Object
13.5
19.5
28.5
42.5
49
12
16.5
24.5
36
42.5
Aircraft stand taxilane to object
*
18 m if used by aircraft with a wheelbase equal to or greater than 18 m.
23 m is used by aircraft with an outer main gear wheel span equal to or greater than 9 m.
‡
4.5 m. if intended to be used by airplane with a wheelbase equal to or greater than 18 m.
Source: International Civil Aviation Organization [2, 3, 4].
†
TABLE 6-20
Taxiway Dimensional Standards, m
separation is also applicable to aircraft traversing through a taxiway
on an apron or ramp. This separation may have to be increased to
accommodate pavement widening on taxiway curves. It is recommended that a separation of at least 2.6 times the wheelbase of the
most demanding aircraft be provided to accommodate a 180° turn
when the pavement width is designed for tracking the nose wheel on
the centerline.
The taxilane centerline to a parallel taxilane centerline or fixed or
movable object separation in the terminal area is predicated on a
wingtip clearance of approximately half of that required for an apron
taxiway. This reduction in clearance is based on the consideration
that taxiing speed is low in this area, taxiing is precise, and special
guidance techniques and devices are provided. This requires a wingtip clearance or wingtip-to-object clearance of 0.1 times the wingspan
of the most demanding aircraft plus 10 ft. Therefore, this establishes
a minimum separation between the taxilane centerlines of 1.1 times
the wingspan of the most demanding aircraft plus 10 ft, and between
a taxilane centerline and a fixed or movable object of 0.6 times the
wingspan of the most demanding aircraft plus 10 ft [6]. Therefore,
when dual parallel taxilanes are provided in the terminal apron area,
the taxilane object-free area becomes 2.3 the wingspan of the most
demanding aircraft plus 30 ft.
231
232
Airport Design
Aerodrome Code Letter
A
B
C
D
E
Gradient (%)
Pavement longitudinal
Maximum
3.0
3.0
1.5
1.5
1.5
Maximum change
4.0
4.0
3.33
3.33
3.33
2.0
2.0
1.5
1.5
1.5
Upward
3.0
3.0
2.5
2.5
2.5
Downward
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
25
25
30
30
30
Pavement transverse
Maximum
Strip
Maximum transverse
Graded portion
Ungraded portion
Upward
Vertical curve (m)
Minimum length∗
*
For each 1 percent of grade change.
Source: International Civil Aviation Organization [2, 3, 4].
TABLE 6-21 Taxiway Gradient Standards
The separation criteria are presented in Table 6-18. The values
indicated in this table are based upon the specifications using the
largest wingspan in each airplane design group. As noted in this
table, the required separations may be reduced to those that would
result using the actual wingspan of the design aircraft.
ICAO Separation Criteria
The separation criteria adopted by ICAO are also predicated upon
the wingtips of the aircraft for which the taxiway and taxilane system
have been designed and providing a minimum wingtip clearance on
these facilities, but also consider a minimum clearance between the
outer main gear wheel and the taxiway edge. The required separation
between taxiways or between a taxiway and a taxilane requires a
minimum wingtip clearance, C1, of 3 m for aerodrome code letter
A and B runways, 4.5 m for aerodrome code letter C runways, and
Geometric Design of the Airfield
7.5 m for aerodrome code letter D and E runways. The minimum
clearance between the edge of each taxiway and the outer main gear
wheels, the taxiway edge safety margin U1, is given in Table 6-20. This
clearance provides a minimum taxiway centerline to a parallel taxiway centerline or taxilane centerline separation given by Eq. (6-1).
STT = WS + 2U1 + C1
(6-1)
where STT = minimum taxiway-to-taxiway or taxiway-to-taxilane
separation
WS = wingspan of the most demanding aircraft
U1 = taxiway edge safety margin
C1 = minimum wingtip clearance
Therefore, for example, an ICAO aerodrome code letter E runway, which accommodates aircraft with wingspans up to 65 m,
requires a taxiway centerline to a taxiway centerline or a taxilane centerline separation from Eq. (6-1) of 65 + 2(4.5) + 7.5 = 81.5 m.
The required separation between a taxiway centerline or an
apron taxiway centerline and a fixed or movable object is found from
Eq. (6-2).
STO = 0.5 WS + U1 + C2
(6-2)
where STO is the minimum taxiway or apron taxiway to a fixed or
movable object separation and C2 is the required clearance between a
wingtip and an object.
The required clearance between a wingtip and an object C2 is 4.5 m
for aerodrome code letter A runways, 5.25 m for aerodrome code letter B runways, 7.5 m for aerodrome code letter C runways, and 12 m
for aerodrome code letter D and E runways.
The required separation between an aircraft stand taxilane centerline and a fixed or movable object is found from Eq. (6-3).
SATO = 0.5 WS + U2 + C1
(6-3)
where SATO is the minimum aircraft stand taxilane to fixed or movable
object separation and U2 is the aircraft stand safety margin.
Since aircraft moving on the aircraft stand taxilane are moving
at low speed and are often under positive ground guidance, the
aircraft stand safety margin is less than on the taxiway system.
The value for this safety margin U2 is 1.5 m for aerodrome code
letter A and B airports, 2 m for aerodrome code letter C airports,
and 2.5 m for aerodrome code letter D or E airports. The taxiway
and taxilane separation criteria adopted by ICAO are given in
Table 6-20.
233
234
Airport Design
Sight Distance and Longitudinal Profile
As in the case of runways, the number of changes in longitudinal
profile for taxiways is limited by sight distance and minimum distance between vertical curves.
The FAA does not specify line of sight requirements for taxiways
other than those discussed earlier related to runway and taxiway
intersections. However, the sight distance along a runway from an
intersecting taxiway needs to be sufficient to allow a taxiing aircraft to
enter or cross the runway safely. The FAA specifies that from any point
on the taxiway centerline the difference in elevation between that
point and the corresponding point on a parallel runway, taxiway, or
apron edge is 1.5 percent of the shortest distance between the points.
ICAO requires that the surface of the taxiway should be seen for
a distance of 150 m from a point 1.5 m above the taxiway for aerodrome code letter A runways, for a distance of 200 m from a point 2 m
above the taxiway for aerodrome code letter B runways, and for a
distance of 300 m from a point 3 m above the taxiway for aerodrome
code letter C, D, or E runways.
In regard to longitudinal profile of taxiways, the ICAO does not
specify the minimum distance between the points of intersection of
vertical curves. The FAA specifies that the minimum distance for both
utility and transport category airports should be not less than the
product of 100 ft multiplied by the sum of the absolute percentage
values of change in slope.
Exit Taxiway Geometry
The function of exit taxiways, or runway turnoffs as they are sometimes called, is to minimize runway occupancy by landing aircraft.
Exit taxiways can be placed at right angles to the runway or some
other angle to the runway. When the angle is on the order of 30°, the
term high-speed exit is often used to denote that it is designed for
higher speeds than other exit taxiway configurations. In this chapter,
specific dimensions for high-speed exit, right-angle exit (low-speed)
taxiways are presented. The dimensions presented here are the results
obtained from research conducted many years ago [13] and subsequent research conducted by the FAA.
The earlier tests [13] were conducted on wet and dry concrete and
asphalt pavement with various types of civil and military aircraft in
order to determine the proper relationship between exit speed and
radii of curvature and the general configuration of the taxiway. A significant finding of the tests was that at high speeds a compound curve
was necessary to minimize tire wear on the nose gear and, therefore,
the central or main curve radius R2 should be preceded by a much
larger radius curve R1.
Aircraft paths in the test approximated a spiral. A compound
curve is relatively easy to establish in the field and begins to approach
Geometric Design of the Airfield
the shape of a spiral, thus the reason for suggesting a compound
curve. The following pertinent conclusions were reached as a result
of the tests [13]:
1. Transport category and military aircraft can safely and comfortably turn off runways at speeds on the order of 60 to 65 mi/h on
wet and dry pavements.
2. The most significant factor affecting the turning radius is
speed, not the total angle of turn or passenger comfort.
3. Passenger comfort was not critical in any of the turning movements.
4. The computed lateral forces developed in the tests were substantially below the maximum lateral forces for which the
landing gear was designed.
5. Insofar as the shape of the taxiway is concerned, a slightly
widened entrance gradually tapering to the normal width of
taxiway is preferred. The widened entrance gives the pilot
more latitude in using the exit taxiway.
6. Total angles of turn of 30° to 45° can be negotiated satisfactorily. The smaller angle seems to be preferable because
the length of the curved path is reduced, sight distance is
improved, and less concentration is required on the part of
the pilots.
7. The relation of turning radius versus speed expressed by the
formula below will yield a smooth, comfortable turn on a wet
or dry pavement when f is made equal to 0.13.
R2 =
V2
15 f
(6-4)
where V is the velocity in mi/h and f is the coefficient of friction.
8. The curve expressed by the equation for R2 should be preceded by a larger radius curve R1 at exit speeds of 50 to 60
mi/h. The larger radius curve is necessary to provide a gradual transition from a straight tangent direction section to a
curved path section. If the transition curve is not provided
tire wear on large jet transports can be excessive.
9. The length of the transition curve can be roughly approximated by the relation
L1 =
V3
CR2
(6-5)
where V is in feet per second, R2 is in feet, and C was found
experimentally to be on the order of 1.3.
235
236
Airport Design
10. Sufficient distance must be provided to comfortably decelerate an aircraft after it leaves the runway. It is suggested that
for the present this distance be based on an average rate of
deceleration of 3.3 ft/s2. This applies only to transport category aircraft. Until more experience is gained with this type
of operation the stopping distance should be measured from
the edge of the runway.
A chart showing the relationship of exit speed to radii R1 and R2,
and length of transition curve L1 is given in Fig. 6-33.
ICAO has indicated the relationship between aircraft speed and
the radius of curvature of taxiway curves as illustrated in Table 6-22.
For high-speed exit taxiways ICAO recommends a minimum radius
4000
3600
R2
L1
3200
R1
2800
350
R1 = radius of entrance curve
L1 = length of entrance curve
300
th
L1
ng
Le
250
1
2000
1600
200
1200
150
s
iu
800
ad
R2
100
R
400
0
50
0
FIGURE 6-33
10
20
30
40
50
Speed, in miles per hour
60
Radii of curvature and entrance curves for taxiways.
0
70
L1, in feet
R2 = radius of central curve
Ra
diu
sR
Radius in feet
2400
Geometric Design of the Airfield
Taxiing Speed
mph
Radius of Exit curve
kph
Feet
Meters
10
16
50
15
20
32
200
60
30
48
450
135
40
64
800
240
50
80
1,250
375
60
96
1,800
540
Source: International Civil Aviation Organization [4].
TABLE 6-22
Radii of Curvature for Transport Category Aircraft
of curvature for the taxiway centerline of 275 m (900 ft) for aerodrome
code number 1 and 2 runways and 550 m (1800 ft) for aerodrome code
number 3 and 4 runways. This will allow exit speeds under wet conditions of 65 km/h (40 mi/h) for aerodrome code number 1 and 2
runways and 93 km/h (60 mi/h) for aerodrome code number 3 and 4
runways. It also recommends a straight tangent section after the turnoff curve to allow exiting aircraft to come to a full stop clear of the
intersecting taxiway when the intersection is 30°. This tangent distance should be 35 m (115 ft) for aerodrome code number 1 and 2
runways and 75 m (250 ft) for aerodrome code number 3 and 4 runways [2, 4].
A configuration for an exit speed of 60 mi/h and a turnoff angle
of 30° is shown in Fig. 6-34. The FAA recommends that the taxiway
centerline circular curve be preceded by a 1400-ft spiral to smooth the
transition from the runway centerline to the taxiway exit circular
curve. ICAO recommends the same geometry for both of these highspeed exits. Right-angle or 90° exit taxiways, although not desirable
from the standpoint of minimizing runway occupancy, are often
C
L TAXIWAY
IC
FL
TR
25' R (7.5 M)
30°
C
L RUNWAY
FIGURE 6-34
High-speed exit taxiway.
50 M)
F
AF
800' R (2
OW
25' R (7.5 M)
237
Airport Design
TAXIWAY C
L
F
L
L
R
W
238
W
F
L
W
R
L
W
TAXIWAY C
L
L
W
C
L
FIGURE 6-35
F
R
W
L
Common taxiway exit and intersection configurations.
constructed for other reasons. The configurations for a 90° exit and
other common taxiway intersection configurations are illustrated in
Fig. 6-35. The dimensions labeled in Fig. 6-35 are determined by the
aircraft design group of the design aircraft. These dimensional standards are provided in Table 6-23.
Location of Exit Taxiways
The location of exit taxiways depends on the mix of aircraft, the approach
and touchdown speeds, the point of touchdown, the exit speed, the rate
of deceleration, which in turn depends on the condition of the pavement surface, that is, dry or wet, and the number of exits.
Geometric Design of the Airfield
Airplane Design Group
I
II
III†
Item
Dim.*
Radius of
taxiway turn‡
R
75
75
100
Length of lead- L
in to fillet
50
50
Fillet radius
for tracking
centerline
F
60
Fillet radius
for judgmental
oversteering
symmetrical
widening§
F
Fillet radius for F
judgmental
IV
V
VI
150
150
170
150
250
250
250
55
55
85
85
85
62.5
57.5
68
105
105
110
62.5
57.5
60
97
97
100
Oversteering
one side
widening¶
∗
Letters correspond to the dimensions on Fig. 6-35.
Airplanes in airplane design group III with a wheelbase equal to or greater than 60 ft
should use a fillet radius of 50 ft.
‡
Dimensions for taxiway fillet designs relate to the radius of taxiway turn specified.
§
The center sketch of Fig. 6-35 displays pavement fillets with symmetrical taxiway
widening.
¶
The lower sketch of Fig. 6-35 displays a pavement fillet with taxiway widening on one
side.
†
TABLE 6-23
FAA Taxiway Curvature Dimensional Standards, ft
While the rules for flying transport aircraft are relatively precise,
a certain amount of variability among pilots is bound to occur especially in respect to braking force applied on the runway and the distance from runway threshold to touchdown. The rapidity and the
manner in which air traffic control can process arrivals is an extremely
important factor in establishing the location of exit taxiways. The
location of exit taxiways is also influenced by the location of the runways relative to the terminal area.
Several mathematical analyses or models have been developed
for optimizing exit locations. While these analyses have been useful
239
240
Airport Design
in providing an understanding of the significant parameters affecting
location, their usefulness to planners has been limited because of the
complexity of the analyses and a lack of knowledge of the inputs
required for the application of the models. As a result greater use is
made of much more simplified methods.
The landing process can be described as follows. The aircraft
crosses the runway threshold and decelerates in the air until the
main landing gear touches the surface of the pavement. At this
point the nose gear has not made contact with the runway. It may
take as long as 3 s to do so. When it does, reverse thrust or wheel
brakes or a combination of both are used to reduce the forward
speed of the aircraft to exit velocity. Empirical analysis has revealed
that the average deceleration of air-carrier aircraft on the runway
is about 5 ft/s2.
In the simplified procedure, an aircraft is assumed to touch down
at 1.3 times the stall speed for a landing weight corresponding to 85
percent of the maximum structural landing weight. In lieu of computing the distance from threshold to touchdown, touchdown
distances are assumed as fixed values for certain classes of aircraft.
Typically these values range from 500 to 1500 ft from the runway
threshold. To these distances are added the distances to decelerate to
exit speed. These relationships may be approximated by Eqs. (6-6)
and (6-7).
D = Dtd + De
(6-6)
where D = distance from the runway threshold to the exits
Dtd = distance from the runway threshold to the point where the
aircraft touches down
De = the distance from the touchdown point to the exit
De =
Vtd2 − Ve2
2a
(6-7)
where Vtd = aircraft speed at touchdown
Ve = exit speed of the aircraft
a = deceleration of the aircraft on the runway
Although approach and touchdown speeds vary, they can be
approximated for locating exit taxiways. At predominantly air carrier
airports air traffic control authorities request general aviation aircraft
to increase their speeds above normal to reduce the wide range in
speed between air carriers and general aviation. At these airports,
the normal approach speeds for general aviation are probably not
applicable.
If it is assumed that the distances to touchdown are 1500 ft for air
carrier aircraft and 1000 ft for twin-engine general aviation aircraft, a
Geometric Design of the Airfield
Type of Aircraft
Touchdown
Speed, kn
Exit Speed, mi/h
60
15
Small propeller
GA single engine
GA twin engine
60
2,400
1,800
95
2,800
3,500
Large jet
130
4,800
5,600
Heavy jet
140
6,400
7,100
TABLE 6-24
Approximate Taxiway Exit Location from Threshold, ft
high-speed exit accommodates aircraft exiting the runway at an exit
speed of 60 mi/h and a regular exit accommodates aircraft exiting the
runway at 15 mi/h, then using approximate touchdown speeds, the
approximate exit locations for various types of aircraft may be found
as shown in Table 6-24.
These locations are derived using standard sea-level conditions.
Altitude and temperature can affect the location of exit taxiways.
Altitude increases distance on the order of 3 percent for each 1000 ft
above sea level and temperature increases the distance 1.5 percent for
each 10°F above 59°F.
During runway capacity studies conducted for the FAA, data were
collected on exit utilization at various large airports in the United
States [18]. These data, which are tabulated in Table 6-25, indicate the
cumulative percentage of each class of aircraft which have exited the
runway at exits located at various distances from the arrival threshold. On the basis of these studies, runway exit ranges from the arrival
threshold are used in runway capacity studies [5]. These exit ranges
are given in Table 6-26. Comparisons between the approximate relationships given in Table 6-24 and the data given in Tables 6-25 and
6-26 indicate that fairly good correspondence results. Variations
which occur are due to pilot technique and preference in choosing
exits, the wide range of performance characteristics demonstrated by
various aircraft in the aircraft approach categories, altitude and temperature considerations, and the amount of runway available for
landing. The latter factor is very important because if pilots recognize
that the amount of runway available is near the minimum for a particular aircraft they are more likely to touch down closer to the runway threshold and apply larger than normal deceleration and braking to the aircraft.
It is recommended that the point of intersection of the centerlines
of taxiway exits and runways, which are up to 7000 ft in length and
accommodate aircraft approach category C, D, and E aircraft, should
241
242
Airport Design
Dry Runways
Distance from
Threshold to Exit, ft
A
Regular Exits
High Speed Exits
Aircraft Class
Aircraft Class*
B
*
C
D
A
B
C
D
0
0
0
0
0
0
0
0
0
1000
6
0
0
0
13
0
0
0
2000
84
1
0
0
90
1
0
0
3000
100
39
0
0 100
40
0
0
4000
98
8
0
98
26
3
5000
100
100
76
55
98
95
49
9
6000
92
71
7000
100
98
8000
100 100
100
Wet Runways
Distance from
Threshold to Exit, ft
Aircraft Class*
A
B
C
D
0
0
0
0
0
1000
4
0
0
0
2000
60
0
0
0
3000
96
10
0
0
4000
100
80
1
0
100
12
0
6000
48
10
7000
88
64
8000
100
93
5000
9000
100
∗
The aircraft class is the classification of aircraft based upon maximum certified takeoff
weight [5].
Source: Federal Aviation Administration [18].
TABLE 6-25
Percentage of Aircraft Exiting at Exits Located at Various Dry
Runways
be located about 3000 ft from the arrival threshold and 2000 ft from
the stop end of the runway. To accommodate the average mix of aircraft on runways longer than 7000 ft, intermediate exits should be
located at intervals of about 1500 ft. At airports where there are extensive
Geometric Design of the Airfield
Mix Index*
Exit Range from Arrival Threshold
0–20
2000–4000
21–50
3000–5500
51–80
3500–6500
81–120
5000–7000
121–180
5500–7500
∗
Mix Index is equal to the percentage of Class C aircraft plus three an aircraft with
a maximum certified takeoff weight in excess of class D aircraft, where a class C
aircraft is an aircraft with a maximum certified takeoff weight greater than
12,500 lb and up to 300,000 lb and a class D aircraft is an aircraft with a maximum certified takeoff weight in excess of 300,000 lb.
Source: Federal Aviation Administration [5].
TABLE 6-26 Exit Range Appropriate to Runways Serving Aircraft of Different
Arrival Mix Indices, ft
operations with aircraft approach category A and B aircraft, an exit
located between 1500 and 2000 ft from the landing threshold is recommended.
Planners often find that the runway configuration and the location of the terminal at the airport often preclude placing the exits at
locations based on the foregoing analysis. This is nothing to be
alarmed about since it is far better to achieve good utilization of the
exits than to be too concerned about a few seconds lost in occupancy
time.
When locating exits it is important to recognize local conditions
such as frequency of wet pavement or gusty winds. It is far better to
place the exits several hundred feet farther from the threshold than
to have aircraft overshoot the exits a large amount of time. The standard deviation in time required to reach exit speed is on the order
of 2 or 3 s. Therefore, if the exits were placed down the runway as
much as two standard deviations from the mean, the loss in occupancy time would only be 4 to 6 s. In planning exit locations at
specific airports, one needs to consult with the airlines relative to
the specific performance characteristics of the aircraft intended for
use at the airport.
The total occupancy time of an aircraft can be roughly estimated
using the following procedure. The runway is divided into four components, namely, flight from threshold to touchdown of main gear,
time required for nose gear to make contact with the pavement after
the main gear has made contact, time required to reach exit velocity
from the time the nose gear has made contact with the pavement and
brakes have been applied, and time required for the aircraft to turn
243
244
Airport Design
off on to the taxiway and clear the runway. For the first component it
can be assumed that the touchdown speed is 5 to 8 kn less than the
speed over the threshold. The rate of deceleration in the air is about
2.5 ft/s2. The second component is about 3 s and the third component
depends upon exit speed. Time to turnoff from the runway will be on
the order of 10 s. Thus the total occupancy time in seconds can be
approximated by Eq. (6-8).
Ri =
Vot − Vtd
V − Ve
+ 3 + td
+t
2 a1
2 a2
(6-8)
where Ri = runway occupancy time, s
Vot = over the threshold speed, ft/s
Vtd = touchdown speed, ft/s
Ve = exit speed, ft/s
t = time to turnoff from the runway after exit speed is reached, s
a1 = average rate of deceleration in the air, ft/s2
a2 = average rate of deceleration on the ground, ft/s2
During the runway capacity studies cited earlier [18] data were
also collected on runway occupancy time. These data, which are tabulated in Table 6-27, indicate the total runway occupancy time of each
class of aircraft which have exited the runway at exits located at various distances from the arrival threshold. As may be observed in this
table, typical runway occupancy times for 60 mi/h high-speed exits
are 35 to 45 s. The corresponding time for a 15 mi/h regular exit is 45
to 60 s for air carrier aircraft.
Design of Taxiway Curves and Intersections
The basic design of taxiway curves and intersections for three of the
most common types of taxiway intersections have been developed by
the FAA [6]. These designs have been taken from this reference and
were shown in Fig. 6-35. The dimensions recommended by the FAA
for the taxiway width, centerline radius, fillet radius (inner edge
radius), and the length of the fillet lead-in are given in Table 6-23. The
dimensions given for the fillet radius in this table are related to the
taxiway centerline radius.
When an aircraft negotiates a turn with the nose wheel tracking a
predetermined curved path, such as a taxiway centerline, the midpoint of the main undercarriage does not follow the same path of the
nose gear because of the fairly large distance from the nose gear to the
main undercarriage. The relationship between the centerline, which
is being tracked by the nose wheel, and position of the main undercarriage are shown in Fig. 6-36. At any point on the curve the distance
between the curved path followed by the nose wheel and the midpoint of the undercarriage of main landing gear is referred to as the
Geometric Design of the Airfield
Dry Runways
Distance from Threshold
to Exit, ft
Regular Exits
High Speed Exits
Aircraft Class
Aircraft Class*
*
A
B
C
D
A
B
C
D
32
35
35
38
41
35
35
47
47
49
44
44
56
56
54
54
75
65
65
63
63
76
75
73
73
9000
76
75
82
82
10000
76
75
85
85
11000
76
75
90
90
0
24
19
1000
24
27
27
24
2000
34
27
35
24
3000
44
37
29
43
4000
55
46
38
5000
65
56
6000
76
65
7000
76
8000
Wet Runways
Distance from Threshold
to Exit, ft
Aircraft Class*
A
B
C
D
0
24
1000
24
2000
34
27
3000
44
37
30
4000
55
47
38
5000
65
56
47
47
6000
76
65
56
56
7000
99
99
65
65
8000
73
73
9000
82
82
∗
The aircraft class is the classification of aircraft based upon maximum certified takeoff
weight [5]
Source: Federal Aviation Administration [8].
TABLE 6-27
Runway Occupancy Time of Aircraft Exiting at Exits Located at
Various Distances from the Runway Arrival Threshold, s
245
Airport Design
Castor angle C
se
Wh
ee
lba
R
tax
f CL
so
diu
Ra
iwa
y
90°
C
L of
246
Edge of pavement
Midpoint main
landing gear
Track-in
Safety margin S
FIGURE 6-36
Path of main gear on curve.
track-in. The track-in varies, increasing progressively during the turning maneuver. It decreases as the nose gear begins to follow the tangent to the curve. Knowing the path of the main gear, the radius of
the fillet can be determined by adding an appropriate taxiway edge
safety margin S between the outside edge of the tire on the main landing gear closest to the center of the path followed by the nose wheel
and the edge of the pavement.
The nose wheel steering angle, the castor angle C is defined as the
angle formed by the longitudinal axis of the aircraft and the direction
of movement of the nose wheel, or some other reference point or
datum point such as the location of the pilot in the cockpit. For preliminary design it is sufficiently accurate to assume that the datum
point is the nose wheel.
The size of the fillet depends not only on the wheelbase of the
aircraft, the radius of the curve, the width of the taxiway, and the total
change in direction, but also on the path that the aircraft follows on
the turn. There are three ways in which an aircraft can be maneuvered on a turn. One is to establish the centerline of the taxiway as the
path of the nose gear. This is called nose wheel on centerline tracking.
Another is to establish the centerline of the taxiway as the path
directly beneath the pilot and assume that this path is followed. This
is called maintaining cockpit over the centerline tracking. The last is
to assume that the nose gear will follow a path offset outward of the
Geometric Design of the Airfield
centerline. This is called judgmental oversteering tracking. The latter
type of tracking will result in the least amount of taxiway widening
but results in greater runway occupancy time and the possibility of
pilot error in judging the turn to follow. While there is no agreement
on which procedure is desirable, usually maintaining the cockpit
over the centerline tracking is preferred.
The principal dimensions of the aircraft related to tracking a curve
were given in Fig. 6-36. The geometry of the aircraft tracking the centerline curve from the point of curvature, PC, to the point of tangency,
PT, and the various terms used in the equations below to define the
movement of the aircraft are given in Fig. 6-37.
The maximum angle formed between the tangent to the centerline and the longitudinal axis of the aircraft will occur at the end of
the curve when the nose wheel is at the point of tangency. This angle,
called Amax, may be approximated by
Amax = sin−1 (d/R)
(6-9)
where d is the distance from the nose wheel or the pilot cockpit position to the center of the main undercarriage; the wheelbase of the
aircraft is often used to approximate this distance and R is the radius
the nose wheel or the pilot is tracking on the curve.
The maximum nose wheel steering angle, the castor angle, the
angle between the longitudinal axis on the nose gear and the longitudinal axis of the aircraft, Bmax, is given by
Bmax = tan−1( w/d tan Amax)
(6-10)
where w is the wheelbase of the aircraft.
Sc
A
Taxiway
Guideline
PC
Amax
R
M
F
Point Tracking
Guideline
PT
St
FIGURE 6-37
W
L
Taxiway fillet design geometry.
Main Gear
u
d
247
248
Airport Design
The required fillet radius F is given by
F = (R2 + d2 − 2Rd sin Amax)0.5 − 0.5u − M
(6-11)
where u is undercarriage width, that is, the distance between the outside tires on the main gear and M is the minimum distance required
between the edge of the outside tire and the edge of the pavement,
that is, the edge safety margin.
The length of the lead-in to the fillet is given by
L = d ln
(4d tan 0 . 5 Amax )
−d
W − u − 2M
(6-12)
where W is the taxiway width on the tangent and ln represents the
natural logarithm.
These equations may be solved for a given aircraft tracking a
curve of radius R to find the necessary lead-in and fillet radius to
maintain a minimum edge safety margin between the tire and pavement edge. If the value of the maximum nose wheel steering angle,
Bmax, exceeds 50° it is recommended that the radius of the centerline
curve R which the nose wheel is tracking be increased.
The use of these equations in determining the critical taxiway
curve design parameters is shown in Example Problem 6-3.
Example Problem 6-3
Determine the minimum lead-in and the radius of the fillet to maintain the
cockpit over the centerline for an aircraft with a 156.1-ft wingspan, a wheelbase
of 64.6 ft, undercarriage width of 34.25 ft, and the distance between the main
undercarriage and cockpit equal to 72.1 ft. The aircraft is moving between two
parallel taxiways through a connecting taxiway which has a centerline perpendicular to the parallel taxiways.
With a wingspan of 156.1 ft this aircraft is in airplane design group IV. From
Table 6-23, the taxiway width is 75 ft, the minimum safety margin is 15 ft, the
recommended centerline radius is 150 ft, the recommended length of the fillet
lead-in is 250 ft and the recommended fillet radius is 85 ft.
To verify that these recommended values are acceptable, we can use Eqs. (6-10)
through (6-13). From Eq. (6-10), we have
Amax = sin−1 (d/R)
or
Amax = sin−1 (72.1/150) = 29°
From Eq. (6-11),
Bmax = tan−1(w/d tan Amax)
or
Bmax = tan−1 [(64.5/72.1) tan 29°] = 27°
Geometric Design of the Airfield
Since this is less than 50° the radius is adequate.
From Eq. (6-12), we have
F = (R2 + d2 − 2Rd sin Amax)0.5 − 0.5u − M
or
F = [1502 + 72.12 −(2)(150)(72.1) sin 29°]0.5 − 0.5(34.25) − 15
F = 100.1 ft
From Eq. (6-12),
L=
d ln( 4d tan 0 . 5 Amax )
−d
W − u − 2M
⎡(4)(72 . 1)(tan 14 . 5 °)⎤
L = 72 . 1 ln ⎢
⎥ − 72 . 1
⎣ 75 − 34 . 25 − (2)(15) ⎦
or
L = 68 ft
Therefore, both the required fillet radius and the required length of the lead-in
to the fillet for this specific aircraft are both well within those recommended for
the airplane design group to which this aircraft is assigned.
End-Around Taxiways
In an effort to reduce the number of times aircraft must cross a runway when traveling around an airfield, the FAA has allowed for the
design of taxiways that traverse beyond runway thresholds. These
taxiways, known as end-around taxiways, are designed to both
reduce the risk of runway incursions and increase the overall efficiency operations on the airfield. For safety considerations, primarily
concerned with the transient presence of aircraft immediately off the
end of the runway, the FAA has established specific design standards
for end-around taxiways. An example of end-around taxiway configuration is shown in Fig. 6-38.
End-around taxiways must remain outside of the runway safety
area, and outside of any ILS critical areas. In addition, the tail height
of the critical design aircraft at the airport must not exceed any critical Part 77 or TERPS surfaces, when on the end-around taxiway. Furthermore, the location of the end-around taxiway should provide for
any aircraft departing on the runway to clear any object on the taxiway by at least 35 ft vertically and 200 ft horizontally from the runway centerline.
249
250
Airport Design
TAXIWAY
DISTANCE FROM
RUNWAY END (Ds)
RUNWAY R
VISUAL
SCREEN R
De
TAXIWAY
RUNWAY L
VISUAL
SCREEN L
De
END
AROUND
TAXIWAY
DISTANCE FROM
RUNWAY END (Ds)
ALTERNATE STAGGERED
LAYOUT FOR ACCESS
TAXIWAY
DISTANCE MAY VARY
1500' MINIMUM
FIGURE 6-38
End-around taxiway.
A diagonal stripe screen is required to be placed between the end
of the runway and the end-around taxiway, to provide pilots on the
runway visual clarity that any aircraft on the end-around taxiway is
not on the runway. An illustration of this screen is found in Fig. 6-39.
Aprons
Holding Aprons
Holding aprons, holding pads, run-up pads, or holding bays as they
are sometimes called, are placed adjacent to the ends of runways. The
areas are used as storage areas for aircraft prior to takeoff. They are
Predominant Flow
FIGURE 6-39
End-around taxiway screen.
Geometric Design of the Airfield
Runway
CL
Taxiway
CL
Runway
CL
Taxiway
CL
FIGURE 6-40
Typical holding pad configurations.
designed so that one aircraft can bypass another whenever this is necessary. For piston-engine aircraft the holding apron is an area where
the aircraft instrument and engine operation can be checked prior to
takeoff. The holding apron also provides for a trailing aircraft to
bypass a leading aircraft in case the takeoff clearance of the latter
must be delayed for one reason or another, or if it experiences some
malfunction. There are many configurations of holding aprons, two of
which are shown in Fig. 6-40. The important design criteria are to
provide adequate space for aircraft to maneuver easily onto the runway irrespective of the position of adjacent aircraft on the holding
apron and to provide sufficient room for an aircraft to bypass parked
aircraft on the holding apron. The recommendations for the minimum separation between aircraft on holding aprons are the same as
those specified for the taxiway object-free area.
The design of a typical flow-through holding pad studied is
shown in Fig. 6-41. Holding pads must be designed for the largest
Runway
CL
Taxiway
CL
Taxiway
CL
FIGURE 6-41
Flow-through bypass holding pad.
251
252
Airport Design
aircraft which will use the pad. The holding pad should be located so
that all aircraft using the pad will be located outside both the runway
and taxiway object-free area and in a position so as not to interfere
with critical ILS signals.
Terminal Aprons and Ramps
Aircraft parking positions, also called aircraft gates or aircraft stands,
on the terminal apron or ramp are sized for the geometric properties
of a given design aircraft, including wingspan, fuselage length and
turning radii, and for the requirements for aircraft access by the vehicles servicing the aircraft at the gates. Both the FAA and ICAO recommend minimum clearances between any part of an aircraft and other
aircraft or structures in the apron area as given in Table 6-28.
Example Problem 6-4 illustrates the determination of the terminal
apron requirements for aircraft.
Example Problem 6-4
Design a terminal apron with two parallel concourses to accommodate gates
for one wide-bodied aircraft and three narrow-bodied aircraft on the face
of each of the concourses. The gate design aircraft for the wide-bodied gates is
the Boeing 767-200 and the gate design aircraft for the narrow-bodied gates is
the McDonnell-Douglas MD-87. Aircraft will park nose-in at each gate and use the
gates in a power-in and push-out mode of operation.
The Boeing 767-200 has a fuselage length of 159 ft 2 in and a wingspan of 156
ft 1 in, which places it in airplane design group IV, and the McDonnell-Douglas
MD-87 has a fuselage length of 130 ft 5 in and a wingspan of 107 ft 10 in, which
places it in airplane design group III.
If the aircraft are arrayed at the concourses as shown in Fig. 6-42, then the
size of the terminal apron and the size of each gate position may be determined
by referencing the specifications requiring specific separations between aircraft
Airplane Design Group or Aerodrome
Code Letter
Minimum Clearance*
Feet
Meters
I
A
10
3.0
II
B
10
3.0
III
C
15
4.5
IV
D
25
7.5
V or VI
E
25
7.5
∗
The FAA recommends the wingtip separation at parking positions to
Source: Federal Aviation Administration [6, 19] and International Civil Aviation Organization [4]
TABLE 6-28
Minimum Clearance between Aircraft and Fixed or Movable Objects
at Terminal Apron Parking Positions
Geometric Design of the Airfield
782'
25'
414'
184' 116' 182' 116' 184'
12'
12'
104'
182'
Concourse
Concourse
158'
129'
129'
726'
129'
206'
146'
Terminal Building
FIGURE 6-42
Terminal apron requirements for Example Problem 6-4.
operating on the taxilanes and between aircraft parked at the concourse gates.
In this problem the FAA specifications will be used and the design will be based
upon the actual dimensions of the aircraft rather than upon the dimensions
of the largest aircraft in the airplane design groups to which these aircraft are
assigned. Therefore, the relevant separations are contained in the footnotes in
Table 6-18.
The Boeing 767-200 is the greater wingspan aircraft and, therefore, the most
demanding aircraft for taxilane dimensions. The separation between taxilane
centerlines is equal to 1.1 times the wingspan of the most demanding aircraft
plus 10 ft. The recommended separation is then equal to (1.1)(156.1) + 20 = 182 ft.
A ground access vehicle lane will be provided behind each aircraft for the use
of aircraft service vehicles. This lane will be 12 ft wide. The distance from the
centerline of each taxilane to a fixed or movable object is equal to 0.6 the wingspan plus 10 ft. Therefore, this distance is (0.6)(156.1) + 10 = 104 ft. Considering
the ground access vehicle lane, the distance from the centerline of each taxilane
to the tail of the aircraft is equal to 104 + 12 = 116 ft.
Table 6-28 indicates that the recommended clearance between the face of each
concourse and the nose of the 767-200 aircraft is 25 ft since this aircraft is in
airplane design group IV. The length of the 767-200 is 159 ft 2 in and, therefore,
the distance from the face of each concourse to the tail of the aircraft is equal to
25 + 156.2 = 182 ft.
Considering each of these recommended separations, the width of the terminal
apron or ramp between the concourses is found to be 782 ft as shown in Fig. 6-42.
The clearance between aircraft wingtips or between the aircraft wing and fixed
or movable objects is recommended to be 0.1 times the wingspan plus 10 ft.
Therefore, the 767-200 requires a clearance between its wingtips and fixed or
253
254
Airport Design
movable objects of 0.1 the wingspan plus 10 ft or (0.1)(156.1) + 10 = 25.6 ft. This
results in a parking position for this aircraft being 156.1 + 25.6 = 182 ft wide by
182 ft long. The MD-87 requires a clearance of (0.1)(107.84) + 10 = 20.8 ft. This
results in a parking position for this aircraft being 107.84 + 20.8 = 129 ft wide.
From Table 6-28 this aircraft may be parked as close to 15 ft to the concourse
since it is in airplane design group III. This results in the length of a parking
position for the MD-87 being 130.42 + 15 = 146 ft. However, since the parking
position for the 767-200 is longer, the actual length provided for the MD-87
is 182 ft.
For aircraft to be moved from their parking positions onto the apron taxilane a
separation from the inside edge of the last gate position to the terminal building
equal to the fuselage length plus 0.1 times the wingspan plus 10 ft is required.
This should allow the aircraft to turn onto the centerline of the taxilane from its
gate position and also allow another aircraft to gain access to the gate position
before the last aircraft at that gate leaves the apron area. The parking arrangement shown in Table 6-13 shows the MD-87 as the closest aircraft to the terminal
building. Therefore, the distance from the centerline of the last gate position to
the terminal building is 130.42 + 54 + (0.1)(107.83) + 10 = 206 ft.
The design must ensure that the clearances provided are adequate based upon
the turning capability of the design aircraft. The analyst should verify using the
procedures discussed earlier in this chapter that the tracking-in of the aircraft
while making a turn from the taxilanes to the parking position will not compromise safe clearances between aircraft. The analyst must also verify for each
aircraft that the turning to access gate positions will ensure that no part of the
aircraft will compromise these safe clearances.
Using the above dimensions results in a ramp length of 726 ft. The dimensions
for all aircraft parking positions or gates are shown in Fig. 6-42.
The terminal apron area for these eight aircraft becomes equal to (778)(726) =
565,800 ft2, which is equal to about 13 acres or a total ramp area per aircraft of
about 1.6 acres. A gate for a 767-200 is (182)(182) = 33,100 ft2, which is about
0.75 acres. The required gate for an MD-87 is (129)(146) = 18,800 ft2 which is
slightly more than 0.4 acres. Useful rules-of-thumb which allow one to estimate
terminal apron gate requirements are a total ramp area of from 1.5 to 2.0 acres
per aircraft gate, and an area of from 0.75 to 1.0 acres per gate for a wide-bodied
aircraft gate position and an area of about 0.5 acres per gate for a narrow-bodied
aircraft gate position.
Terminal Apron Surface Gradients
For fueling, ease of towing and aircraft taxiing, apron slopes or grades
should be kept to the minimum consistent with good drainage
requirements. Slopes should not in any case exceed 2 percent for utility airports and 1 percent for transport airports. At gates where aircraft are being fueled every effort should be made to keep the apron
slope within 0.5 percent.
Control Tower Visibility Requirements
At airports with a permanent air traffic control tower, the runways
and taxiways must be located and oriented so that a clear line of sight
is maintained to all traffic patterns, the final approaches to all runways, all runway structural pavements, all apron taxiways, and other
Geometric Design of the Airfield
operational surfaces controlled by the air traffic control tower. A clear
line of sight to all taxilane centerlines is desirable. Operational surfaces not having a clear unobstructed line of sight from the tower are
designated as uncontrolled or nonmovement areas. At airports without a permanent air traffic control tower, the runways and taxiways
should be located and oriented so that a future tower may be sited in
accordance with the continuous visibility requirements. This requirement may be satisfied where adequate control of aircraft exists by
other means [6].
A typical air traffic control tower site requires between 1 and 4 acres
of land. The site must be large enough to accommodate current and
future building needs including employee parking. Tower sites must
afford maximum visibility to traffic patterns and clear, unobstructed
and direct lines of sight to the runway approaches, the landing area,
and all runway and taxiway surfaces. Most towers penetrate the FAR
Part 77 surfaces and, therefore, are obstructions to aviation and may be
a hazard to air navigation unless an FAA study determines otherwise.
The tower must not derogate the signal generated by any existing or
planned electronic navigational aid or air traffic control facility.
References
1. Advisory Circular Checklist, Advisory Circular AC00-2.6, Federal Aviation
Administration, Washington, D.C., October 15, 1992 annual.
2. Aerodromes, Annex 14 to the Convention on International Civil Aviation, Vol. 1:
Aerodrome Design and Operations, International Civil Aviation Organization,
Montreal, Canada, July 1990.
3. Aerodrome Design Manual, Part 1: Runways, 2d ed., Doc 9157-AN/901,
International Civil Aviation Organization, Montreal, Canada, 1984.
4. Aerodrome Design Manual, Part 2: Taxiways, Aprons and Holding Bays, 2d ed.,
International Civil Aviation Organization, Montreal, Canada, 1983.
5. Airport Capacity and Delay, Advisory Circular AC 150/5060-5, Federal Aviation
Administration, Washington, D.C., 1983.
6. Airport Design, Advisory Circular AC 150/5300-13, Change 14 Federal Aviation
Administration, Washington, D.C., 2008.
7. A Mathematical Model for Locating Exit Taxiways, R. Horonjeff, et al., Institute of
Transportation and Traffic Engineering, University of California, Berkeley, Cal.,
1959.
8. “Calculation of Aircraft Wheel Paths and Taxiway Fillets,” J. W. L. van Aswegen,
Graduate Student Report, Institute of Transportation and Traffic Engineering,
University of California, Berkeley, Cal., July 1973.
9. “Characteristics of High Speed Runway Exit for Airport Design,” A. A.
Trani, A. G. Hobeika, B. J. Kim, H. Tomita, and D. Middleton, International
Air Transportation, Proceedings of the 22nd Conference on International Air
Transportation, American Society of Civil Engineers, New York, N.Y., 1992.
10. Criteria for Approving Category I and Category II Landing Minima for FAR Part
121 Operators, Advisory Circular AC 120-29, Including Changes 1 through 3,
Federal Aviation Administration, Washington, D.C., 1974
11. “Determination of the Path Followed by the Undercarriage of a Taxiing Aircraft,”
Paper prepared by Department of Civil Aviation, Melbourne, Australia.
12. “Determination of Wheel Trajectories,” E. Hauer, Transportation Engineering
Journal, American Society of Civil Engineers, Vol. 96, No. TE4, New York, N.Y.,
November 1970.
255
256
Airport Design
13. Exit Taxiway Location and Design, R. Horonjeff, et al., Report prepared for the
Airways Modernization Board by the Institute of Transportation and Traffic
Engineering, University of California, Berkeley, Cal., 1958.
14. “Movement of Aircraft and Vehicles on the Ground—Taxiway Fillets,” Working
Paper No. 102, 5th Air Navigation Conference of the International Civil Aviation
Organization, Montreal, Canada, October 1967.
15. Optimization of Runway Exit Locations, E. S. Joline, R. Dixon Speas, and Associates,
Manhasset, N.Y.
16. Report of the Department of Transportation Air Traffic Control Advisory Committee,
Vols. 1 and 2, Washington, D.C., December 1969.
17. Runway Length Requirements for Airport Design, Advisory Circular AC 150/53254B, Federal Aviation Administration, Washington, D.C., 2005.
18. Supporting Documentation for Technical Report on Airport Capacity and Delay
Studies, Report No. FAA-RD-76-162, Federal Aviation Administration,
Washington, D.C., 1976.
19. The Apron and Terminal Building Planning Report, Report No. FAA-RD-75-191,
Federal Aviation Administration, Washington, D.C., 1975.
20. “The Design and Use of Flow-Through Hold Pads,” Douglas F. Goldberg,
International Air Transportation, Proceedings of the 22nd Conference on
International Air Transportation, American Society of Civil Engineers, New
York, N.Y., 1992.
21. United States Standard for Terminal Instrument Operations (TERPS), 3d ed.,
FAA Order 8260.3B, Including Changes 1 through 12, Federal Aviation
Administration, Washington, D.C., July 1976.
CHAPTER
7
Structural Design of
Airport Pavements
Introduction
This chapter briefly describes various methods for designing airfield
pavements. The term structural design of airport pavements as used in
this text refers to the determination of the thickness of the components that make up an airfield pavement structure, rather than the
design of pavement materials itself.
Airfield pavement is intended to provide a smooth and safe allweather riding surface that can support the weights of such heavy
objects as aircraft on top of the natural ground base. Airfield pavements are typically designed in layers, with each layer designed to a
sufficient thickness to be adequate to ensure that the applied loads
will not lead to distress or failure to support its imposed loads. The
Federal Aviation Administration provides guidance on the design
of airfield pavements within its Advisory Circular AC 150/5320-6E,
Airfield Pavement Design and Evaluation. Originally published in 1975,
this advisory circular was completely revised in 2008 to consider new
design methods that are based on recently developed computer software models and appropriate for the heaviest of commercial air carrier aircraft. This chapter provides both an account of the historical
pavement design and evaluation methods and details the current
method of pavement design and evaluation. As with any element of
airport planning and design, appropriate Advisory Circulars and
software user guides should be studied and referenced prior to performing any airport pavement analysis. These resources may be downloaded from the FAA at http://www.faa.gov.
Pavement or pavement structure is a structure consisting of one or
more layers of processed materials. A pavement consisting of a
mixture of bituminous material and aggregate placed on highquality granular materials is referred to as flexible pavement. When
the pavement consists of a slab of portland cement concrete (PCC),
it is referred to as rigid pavement. Both structures of pavement are
257
258
Airport Design
typically found at airports, although often there are preferences to a
given type of pavement depending on such factors as the type and
frequency of aircraft usage, climatic conditions, and costs of construction and maintenance.
Figure 7-1 illustrates a cross section of a typically layered airfield
pavement. As illustrated in Fig. 7-1, airfield pavement, whether flexible
or rigid, typically consists of series of layers consisting of a surface
course, base course, and one or more subbase courses, resting on the
ground, or prepared “subgrade” layer.
The surface course consists of a mixture of bituminous material
(generally asphalt) and aggregate ranging in thickness from 2 to
12 in for flexible pavements, and a slab of PCC 8 to 24 in thick for
rigid pavements. The principal function of the surface course is to
provide for smooth and safe traffic operations, to withstand the effects
of applied loads and environmental influences for some prescribed
period of operation, and to distribute the applied load to the underlying layers.
The base course may consist of treated or untreated granular
material. Like the surface course, it must be adequate to withstand
the effects of load and environment and to distribute the applied
loads to the underlying layers. Untreated bases consist of crushed or
uncrushed aggregates. Treated bases consist of crushed or uncrushed
aggregate that has been mixed with a stabilizing material such as
cement or bitumen.
200'
200'
(61 m)
(61 m)
A
200'
200'
(61 m)
(61 m)
P1
P1
A
Transitions
2'' (1 cm) minimum Surface
Surface thickness
Transitions
Notes
Runway width 1
3
2
Runway widths in accordance with
1
applicable advisory circular
Base PCC
Subbase
Subbase
4
4
5
6 @ 25' (7.6 m)
Legend
5
2
Transverse slopes in accordance
with applicable advisory circular
3
Surface, base, PCC, etc., thickness
as indicated on design chart.
4
4 Minimum 12'' (30 cm) up to 30''
(90 cm) allowable.
5
For runways wider than 150' (45.7 m)
this dimension will increase.
Thickness : T
Thickness tapers : T
0.7 T
Thickness : 0.9 T
Thickness : 0.7 T
FIGURE 7-1
200'
(61 m)
Typical plan and cross section for airfield pavement.
Structural Design of Airport Pavements
The subbase course is also composed of treated or untreated
material, typically unprocessed pit-run material or material selected
form a suitable excavation on the site. The function of the subbase is
the same as that of the base. Whether or not a subbase is required, or
how many subbase layers are required, is a function of the type of
loads on the pavement, as well as the type and quality of soil, or subgrade, on which the pavement will be resting. For most rigid pavements, the surface course rests directly on the subbase.
The design of the thickness of each of the above layers is of primary
concern to airport pavement engineers. The two primary factors that
contribute to the design thickness of airfield pavement layers are the
soil base and the volume and weight of the traffic using the pavement.
As such, the first steps in pavement analysis are an investigation of the
soil on which the pavement will be placed, and an estimation of the
annual traffic volume on the pavement.
Soil Investigation and Evaluation
Accurate identification and evaluation of pavement foundations are
essential to the proper design of the pavement structure. The subgrade supports the pavement and the loads placed upon the pavement surface. The function of the pavement is to distribute the loads
to the subgrade, and the greater the capability of the subgrade to support the loads, the less the required thickness of the pavement.
Soil investigation consists of a soil survey to determine the
arrangement of the different layers of soil in relation to the subgrade
elevation, a sampling and testing of the various layers of soil to determine the physical properties of the soil, and a survey to determine the
availability and suitability of local materials for use in the construction of the subgrade and pavement. Surveys and sampling are usually accomplished through soil borings to determine the soil of rock
profile and its lateral extent. The sampled materials are then tested to
determine soil types, gradation or particle sizes, liquid and plastic
limits, moisture-density relationships, shrinkage factors, permeability, organic content, and strength properties. In the United States, soil
surveys are often conducted using a variety of methods, including
referring to U.S. Geological Survey (USGS) geodetic maps, aerial
photography, and soil borings. The FAA recommends borings of
given spacing and depths for soil surveys as illustrated in Table 7-1.
In the United States, evaluation of sampled soils for the purpose
of airfield pavement design is performed according to the U.S. Army
Corps of Engineers Unified Soil Classification (USC or “unified”)
System, as illustrated in Table 7-2. Under the unified system, soils are
initially classified as either coarse-grained, fine-grained, or highly
organic soils. Coarse-grained soils are those that do not filter through
a No. 200 grade sieve. Coarse-grained soils are further divided into
gravels and sands, as a function of the percentage of soil that filters
259
260
Airport Design
Area
Spacing
Depth
Runways and
taxiways
Random across
pavement at 200 ft
(68 m) intervals
Cut areas—10 ft (3.5 m)
below finished grade
Fill areas—10 ft (3.5 m)
below existing ground
Other areas of
pavement
One boring per
10,000 ft2 (930 m2)
of area
Cut areas—10 ft (3.5 m)
below finished grade
Fill areas—10 ft (3.5 m)
below existing ground
Borrow areas
Sufficient tests to
clearly define the
borrow material
To depth of borrow
excavation
Note: For deep fills, boring depths shall be sufficient to determine the extent of consolidation and/or slippage the fill may cause.
TABLE 7-1
Recommended Soil Boring Spacings and Depths
Major Divisions
Coarse-grained soils
more than 50%
retained on No. 200
sieve
Fine-grained
soils 50% or less
retained on No. 200
sieve
Group Symbols
Gravels 50% or more
of coarse fraction
retained on No. 4 sieve
Clean gravels
GW
GP
Gravels with fines
GM
GC
Sands less than 50%
of coarse fraction
retained on No. 4 sieve
Clean sands
SW
SP
Sands with fines
SM
SC
Silts and clays liquid limit 50% or less
ML
CL
OL
Silts and clays liquid limit greater than 50%
MH
CH
OH
Highly organic soils
Note: Based on the material passing the 3-in (75-mm) sieve.
TABLE 7-2
Classification of Soils for Airport Pavement Applications
PT
Structural Design of Airport Pavements
through a No. 4 sieve. Fine grained soils, known also as silts and clays,
are subdivided into two groups on the basis of their liquid limits.
These soils are finally grouped into one of 15 different groupings.
These groupings are
GW: Well-graded gravels and gravel-sand mixtures, little or no
fines
GP: Poorly graded gravels and gravel-sand mixtures, little or no
fines
GM: Silty gravels, gravel-sand-silt mixtures
GC: Clayey gravels, gravel-sand-clay mixtures
SW: Well-graded sands and gravelly sands, little or no fines
SP: Poorly graded sands and gravelly sands, little or no fines
SM: Silty sands, sand-silt mixtures
SC: Clayey sands, sand-clay mixtures
ML: Inorganic silts, very fine sands, rock flour, silty or clayey fine
sands
CL: Inorganic clays of low to medium plasticity, gravelly clays,
silty clays, lean clays
OL: Organic silts and organic silty clays of low plasticity
MH: Inorganic silts, micaceous or diatomaceous fine sands or silts,
plastic silts
CH: Inorganic clays or high plasticity, fat clays
OH: Organic clays of medium to high plasticity
PT: Peat, muck, and other highly organic soils
A flowchart illustrating the procedure for the classification of
soils by the unified system is given in Fig. 7-2. The uses of the various
soil materials for pavement foundations are described in Table 7-3.
It should be noted that column 11 in Table 7-3 refers to the soil’s
“field CBR” value, or “California Bearing Ratio,” a value of the
strength of material used in flexible pavement bases, and column 12
in Table 7-3 refers to the soil’s “subgrade modulus” or “k value,” a
value of the bearing capacity of the soil, estimated using a plate bearing test.
The soil’s field CBR value is determined by the CBR method of
pavement design, which is applied primarily to flexible pavements.
The CBR method of design was developed by the California Division
in 1928. The method subsequently was adopted for military airport
use by the Corps of Engineers, U.S. Army, shortly after the outbreak of
World War II. The outbreak of the war required that a decision be
made with little delay concerning a design method. At the time, there
were no methods available specifically developed for airport pavements. It was apparent that the time required to develop a completed
new method of design would preclude its use in a war emergency
261
262
Make visual examination of soil to determine whether its
highly organic, coarse grained, or fine grained. In border-line
cases determine amount passing No. 200 sieve
Coarse grained
50% or less pass No. 200 sieve.
Highly organic soils
(Pt)
Fibrous texture, color, odor, very
high moisture content, particles of
vegetable matter. (stick, leaves, etc.)
Gravel (G)
Great percentage of course fraction
retained on No. 4 sieve
Fine grained
more than 50% pass No. 200 sieve.
Run sieve analysis
Sand (S)
percentage of coarse
pass No. 4 sieve
Run LL and PL on minus 40 sieve material
L
Liquid limit less than
50
Greater percentage of coarse fraction
Less than
5% pass
No. 200 sieve∗
Between 5%
and 12% pass
No. 200 sieve
More than
12% pass
No. 200 sieve
Less than
5% pass
No. 200 sieve∗
Between 5%
and 12% pass
No. 200 sieve
More than
12% pass
No. 200 sieve
Examine
grain-size
curve
Borderline, to
have double
symbol appropriate to grading
and plasticity
characteristics,
e.g., CW-CM
Run LL and PL
on minus
No. 40 sieve
fraction
Examine
grain-size
curve
Borderline, to have
double symbol
appropriate to
grading and
plasticity characteristics, e.g.,
SW-SM
Run LL and PL
on minus
No. 40 sieve
fraction
Well
graded
Poorly
graded
GW
GP
Below “A” line
and hatched
zone on
plasticity
chart
Limits plot
in hatched
zone on
plasticity
chart
Above “A” line
and hatched
zone on
plasticity
chart
GM
GM–GC
GC
Well
graded
Poorly
graded
SW
SP
Below “A” line
and
hatched
zone on
plasticity
chart
Below “A” line
and hatched
zone on
plasticity
chart
Limits plot
in hatched
zone on
plasticity
chart
Above “A” line
and hatched
zone on
plasticity
chart
Organic
Inorganic
SM
SM–SC
SC
OL
ML
Flowchart for the unified soil classification system.
Above “A” line
and hatched
zone on
plasticity
chart
Below “A”
line on
plasticity
chart
Above “A”
line on
plasticity
chart
Color, odor, possibly
LL and PL on oven
dry soil
Color, odor, possibly
LL and PL on oven
dry soil
Note: Sieve sizes are U.S. Standard.
• If lines interfere with free-draining properties use double symbol such as GW-GM, etc..
FIGURE 7-2
Limits plot
in hatched
zone on
plasticity
chart
H
Liquid limit greater
than 50
ML–CL
CL
Inorganic
Organic
MH
OH
CH
Structural Design of Airport Pavements
program. Consequently, it was decided to review all available methods for the design of highway pavements and to select one which
could be adopted for airfield use. The criteria for selecting a method
were many. Among the more important were (1) simplicity in procedures for testing the subgrade and the pavement components, (2) a
record of satisfactory experience, and (3) adaptation to the airport
problem in a reasonable time. After several months of investigating
of suggested methods, the CBR method was tentatively adopted.
Application of the CBR method enables the designer to determine
the required thickness of the subbase, base, and surface course by
entering a set of design curves using the results of a relatively simple
soil test.
The CBR Test
The CBR test expresses an index of the shearing strength of soil.
Essentially the test consists of compacting about 10 lb of soil into a
6-in-diameter mold, placing a weight, known as a surcharge, on the
surface of the sample, immersing the sample in water for 4 days, and
penetrating the soaked sample with the steel piston approximately
2 in in diameter at a specified rate of loading. The resistance of the soil
to penetration, expressed as a percentage of the resistance for a standard crushed limestone, is the CBR value for the soil. Thus, a CBR of
50 means that the stress necessary for the surcharge to penetrate the
soil sample a specified distance is one-half that required for the surcharge to penetrate the same distance in the standard crushed limestone. The relationship is usually based on a penetration of the piston
of 0.1 in with 1000 lb/in2 used as the stress required to penetrate the
crushed limestone at 0.1 in penetration. As illustrated in Table 7-3,
soils range in CBR values from relatively weak fine-grained and
highly organic soils with CBR values as low as 3, to wide-grained
coarse soils with CBR values as high as 80 (although CBR testing has
been found to be somewhat inaccurate for very gravelly soils, and for
application a CBR value of no higher of 50 should be applied).
The Plate Bearing Test
The modulus subgrade of reaction, or k value of the subgrade is determined by what is known as a field plate bearing test. This test consists of applying loads by means of a hydraulic jack through a jacking
frame on to a steel plate 30 in in diameter on the soil. By loading the
plate, a load-versus-deformation curve is obtained. The k value is
determined to be the pressure required to produce a unit deflection of
the pavement foundation, measured in pounds per cubic inch. k values range from less than 150 (considered “very poor”) to more than
300 (considered “very good”). In general, the greater the coarseness
of the soil, the higher k value and the less deflection for a given loading can be expected.
263
Major Divisions
(1)
Letter
(2)
Gravel
and
gravelly
soils
Coarsegravelly
soils
Sand and
sandy
soils
(3)
Name
(4)
Value
as Base
Directly
under
Wearing
Surface
Value
as Base
Directly
under
Wearing
Surface
Potential Frost
Action
Compressibility and
Expansion
(5)
(6)
(7)
(8)
Drainage
Characteristic
(9)
Unit Dry
Weight
(pcf)
CBR
(10)
(11)
Subgrade
Modulus
k (pci)
(12)
GW
Gravel or sandy
gravel, well graded
Excellent
Good
None to very
slight
Almost none
Excellent
125–140
60–80
300 or
more
GP
Gravel or sandy
gravel, poorly graded
Good
Poor to
fair
None to very
slight
Almost none
Excellent
120–130
35–60
300 or
more
GU
Gravel or sandy
gravel, uniformly
graded
Good to
excellent
Poor
None to very
slight
Almost none
Excellent
115–125
25–50
300 or
more
GM
Silty gravel or silty
sandy gravel
Good
Fair to
good
Slight to medium Very slight
Fair to
poor
130–145
40–80
300 or
more
GC
Clayey gravel or clayey Good to
sandy gravel
excellent
Poor
Slight to medium Slight
Poor to
practically
impervious
120–140
20–40
200–300
SW
Sand or gravelly sand, Good
well graded
Poor
to not
suitable
None to very
slight
Almost none
Excellent
110–130
20–40
200–300
SP
Sand or gravelly sand, Fair to
poorly graded
good
Not
suitable
None to very
slight
Almost none
Excellent
105–120
15–25
200–300
SU
Sand or gravelly sand, Fair to
Poor uniformly Not
good
suitable graded
Poor
None to very
slight
Almost none
Excellent
100–115
10–20
200–300
SM
Silty sand or silty
gravelly sand
Good
Not
suitable
Slight to high
Very slight
Fair to
poor
120–135
20–40
200–300
SC
Clavey sand or clayey
gravelly sand
Fair to
good
Not
suitable
Slight to high
Slight to
medium
Poor to
practically
impervious
105–130
10–20
200–300
ML
Fine
grained
soils
Fair to
good
Not
suitable
Medium to very
high
Slight to
medium
Fair to
poor
100–125
5–15
100–200
Lean clays, sandy
Fair to
clays, or gravelly clays good
Not
suitable
Medium to very
high
Medium
Practically
impervious
100–125
5–15
100–200
Organic silts or lean
organic clays
Poor
Not
suitable
Medium to very
high
Medium to
high
Poor
90–105
4–8
100–200
MH
Micaccous clays or
diatomaceous soils
Poor
Not
suitable
Medium to very
high
High
Fair to
poor
80–105
4–8
100–200
CH
Fat clays
Poor to
very poor
Not
suitable
Medium
High
Practically
impervious
90–110
3–5
50–100
OH
Fat organic clays
Poor to
very poor
Not
suitable
Medium
High
Practically
impervious
80–105
3–5
50–100
Peat, humus and
other
Not
suitable
Not
suitable
Slight
Very high
Low
compressCL
ibility LL
< 50
OL
High
compress
ibility
LL<50
Peat and other
Pt
fibrous organic soils
TABLE 7-3
Silts, sandy silts,
gravelly silts, or
diatomaceous soils
Characteristics of Soil Related to Airport Pavement Foundations
Fair to poor
266
Airport Design
Young’s Modulus (E Value)
The most recent accepted method for determining the strength of
subgrade by the FAA is based upon the elastic modulus of the subgrade, or E, also known as Young’s modulus. In general, a structure’s
E value is its measure of “stiffness” or “elasticity.” The greater the E value,
the more stiff the material, and the less the material is susceptible to
deformation under a given stress load. A pavement’s E value may be
empirically estimated by evaluating its stress to strain ratio, according to Eq. (7-1)
E≡
FL0
Tensile stress σ F/A0
= =
=
Tensile strain ε ∆ L/L0 A0∆L
(7-1)
where E = Young’s modulus (modulus of elasticity)
F = force applied to the pavement
DA0 = original cross-sectional area through which the force is
applied
L = amount by which the shape of the pavement changes
L0 = original shape of the object
Alternatively, the subgrade modulus E value, in pounds per
square inch, may be found using the following conversion formulas:
To find E based on CBR value the equation is
E = 1500 * CBR
(7-2)
To find E based on the modulus of subgrade of reaction, k, the equation is
E = 26k1.284
(7-3)
This conversation is provided by the FAA in its advisory circular primarily to facilitate the transition from the more traditional pavement
design methods to the most current software-based method of pavement design and evaluation.
Effect of Frost on Soil Strength
While there are a variety of soil types, the behavioral properties of
any given type are relatively similar regardless of other climatic characteristics, such as the average ambient temperature and amount of
precipitation. One factor that does significantly impact the strength
of soil, however, is the presence of frost on the surface of or within the
soil, either on a seasonal or a permanent basis.
Frost action, if severe, results in nonuniform heave of pavements
during the winter because of the formation of ice lenses within the
subgrade, known as ice segregation, and in loss of supporting capacity of the subgrade during periods of thaw. Figure 7-3 illustrates the
process of ice segregation.
Structural Design of Airport Pavements
Air temperature
below freezing
Frozen
Surface course
Ice crystals
Base
Water in large void space
freezes into ice crystals
along plane of freezing
temperature.
Unfrozen
Frozen subgrade
Plane of freezing
temperature
Capillary water
Frozen
Ice crystals attract water
from adjacent voids,
which freezes on contact
and forms larger crystals.
Moving water
Unfrozen
Unfrozen subgrade
Frozen
Frost
heaving
Ice lens
Moving water
Unfrozen
FIGURE 7-3
Crystals continue to
grow and join, fed
mostly by capillary
water, forming ice lens.
Vertical pressure exerted
by ice lens heaves
surface.
The process of ice segregation (http:// www.pavementinteractive.org).
During periods of thaw, the ice lenses begin to melt, and the
water which is released cannot drain through the still-frozen soil at
greater depths. Thus, lack of drainage results in loss of strength in
the subgrade. It is also possible that a reduction in stiffness will occur
in subgrade soils during the thaw period, even though ice lenses
may not have formed.
Originally developed by the U.S. Army Corps of Engineers, the
FAA categorizes soils into four “frost groups.” Soils in frost group 1
are least susceptible to frost and associated soil weakening, while soils
in frost group 4 are most susceptible. As illustrated in Table 7-4, those
soils with larger particle sizes, such as the gravelly soils, are found in
frost group 1, while very fine soils are found in frost group 4.
The design of pavements, both flexible and rigid, is modified
slightly depending on the propensity of the soil to encounter frost
and the depth of the frost, known as frost penetration. These considerations are described in further detail later in this chapter.
Subgrade Stabilization
In addition to frost, factors such as poor drainage, adverse surface
drainage, or merely variations in soil depths, contribute to reductions
267
268
Airport Design
Frost Group
Percentage
Finer than 0.02
mm by Weight
Kinds of Soils
Soil
Classification
FG-1
Gravelly soils
3–10
GW, GP, GW-GM,
GP-GM
FG-2
Gravelly soils
sands
10–20
3–5
GM, GW-GM,
GP-GM.
SW, SP, SM,
SW-SM, SP-SM
FG-3
Gravelly soils
Sands, except
very fine silty
sands
Clays, PI above
12
Over 20
Over 15
GM, GC
SM, SC
–
CL, CH
Very fine silty
sands
All silts
Clays, PI = 12
or less
Varved clays
and other fine
grained baded
sediments
Over 15
SM
–
–
ML, MH
CL, CL-ML
–
CL, CH, ML, SM
FG-4
TABLE 7-4
Frost Design Soil Classification
in the stability of a soil. The FAA allows for the stabilization and
treatment of the soils to improve the performance of the constructed
pavement. Two types of soil stabilization exist, mechanical stabilization and chemical stabilization. Mechanical stabilization consists of
embedding cobble or shot rock sheets within the soil. In some cases,
porous concrete or geosynthetics may be used for very soft fine grained
soils. Chemical stabilization is achieved by the addition of proper percentages of cement, lime, fly ash, or combinations of these materials
to the soil.
FAA Pavement Design Methods
Between 1958 and 2006, the FAA established mandates for aircraft
manufacturers to create aircraft, based on their maximum gross takeoff weight and landing gear configuration, that produce loads on
pavements no greater than 350,000 lb, based on the aircraft at the time
that created the heaviest load on airfield pavements, the Douglas DC-8.
As aircraft grew in gross weight, landing gear configurations, with
Structural Design of Airport Pavements
additional wheels and spacings, were created to distribute increased
gross weights, resulting in equivalent per wheel loads not exceeding
the 350,000 lb maximum.
Equivalent Aircraft Method
Historical airfield pavement design methods recommended by the
FAA beginning in 1975 took into account the varying weights and
landing gear configurations of the fleet of aircraft that may regularly
utilize a given airfield’s pavement. This historical method involved
determining the number of total annual aircraft departures by each
type of aircraft and group them into “equivalent annual departures”
of each aircraft in terms of the landing gear configuration of a given
design aircraft, that is, the aircraft in the fleet mix that requires the
greatest pavement strength. This grouping is based on converting the
number of annual departures of all aircraft other than the design aircraft to an equivalent number of annual departures by using the multipliers given in Table 7-5.
The equivalent annual departures of the design aircraft were
determined by summing the equivalent annual departures of each
aircraft in the group, according to the formula given in Eq. (7-4).
1/2
⎛W ⎞
Log R1 = log R2 × ⎜ 2 ⎟
⎝ W1 ⎠
(7-4)
where R1 = equivalent annual departures by the design aircraft
R2 = annual number of departures by an aircraft in terms of
design aircraft landing gear configuration
W1 = wheel load of the design aircraft
W2 = wheel load of the aircraft being converted
To Convert From
To
Multiply Departures By
Single wheel
Dual wheel
0.8
Single wheel
Dual tandem
0.5
Dual wheel
Dual tandem
0.6
Double dual tandem
Dual tandem
1.0
Dual tandem
Single wheel
2.0
Dual tandem
Dual wheel
1.7
Dual wheel
Single wheel
1.3
Double dual tandem
Dual wheel
1.7
TABLE 7-5 Factors for Converting Annual Departures by Aircraft to
Equivalent Annual Departures by Design Aircraft
269
270
Airport Design
Because many of the latest generation aircraft require more complex landing gear configurations that are provided in Table 7-5, a special consideration for very heavy aircraft were made by assigning a
gross takeoff weight of 300,000 lb and a dual-tandem landing gear
configuration to any aircraft with maximum gross takeoff weight
greater than 300,000 lb. This rough approximation was, in part, motivation, to develop an entirely new assessment of fleet mix with
respect to airfield pavement design and evaluation.
Cumulative Damage Failure Method
The current method of airfield pavement design and evaluation now
considers each type of aircraft that uses the pavement explicitly. The
“design aircraft” concept has been replaced by design for fatigue failure expressed in terms of a “cumulative damage factor” (CDF). The
CDF for a given aircraft is a value between 0 and 1 which expresses
the contribution to ultimate pavement failure of the projected number
of uses for each aircraft type that use the pavement. Based on Miner’s
rule, a traditional theory which estimates the amount of use until failure of a pavement, the CDF for a given fleet of aircraft is determined
by Eq. (7-5).
CDF = ∑ (ni/Ni)
(7-5)
where ni is the expected number of annual departures of aircraft i and
Ni is the number of departures of aircraft i that would lead to pavement failure for each aircraft i in the mix.
When CDF meets or exceeds 1, the cumulative predicted number
of operations for each of the aircraft in the mix will lead to failure of
a given pavement system. Any value less than 1 represents the fraction of pavement life that has been effectively “used up.” For example, a CDF of 0.75 would indicate that the pavement has used 75 percent of its useful life, and has 25 percent of its life remaining under
the predicted traffic usage before fatigue failure.
For both the design of flexible and rigid pavements, the current
FAA pavement design method applies a computer software model to
estimate the appropriate thickness of designed pavement layers,
given the Young’s modulus E value of the subgrade and the expected
aircraft fleet mix, such that the CDF of the pavement equals 1 after a
20-year life of the designed pavement.
The FAA approved software, FAA Rigid and Flexible Iterative Elastic Layered Design or FAARFIELD comes equipped with a library of
aircraft, their maximum gross weights, landing gear configuration,
and contribution to CDF for the given pavement design. Figure 7-4
illustrates the “aircraft” window of FAARFIELD with user inputs of
each given aircraft’s estimated departures for the to-be-designed
pavement system.
Structural Design of Airport Pavements
FIGURE 7-4
FAARFIELD aircraft database window.
Design of Flexible Pavements
Flexible pavements consist of a bituminous wearing surface placed
upon a base course and, where required by subgrade conditions, a
subbase. The entire flexible-pavement structure is ultimately supported by the subgrade. The surface course prevents the penetration
of surface water to the base course, provides a smooth, well-bonded
surface free of loose particles, resists the shearing stresses caused by
aircraft loading, and furnishes a texture of nonskid qualities not causing undue tire wear. The course must also be resistant to fuel spillage
and other solvents in areas where maintenance may occur.
The base course is the major structural element of the pavement;
it has the function of distributing the wheel loads to the subbase and
subgrade. It must be designed to prevent failure in the subgrade,
withstand the stresses produced in the base course, resist vertical
pressures tending to produce consolidation and deformation of the
wearing course, and resist volume changes caused by fluctuations in
its moisture content.
Flexible pavement base courses are available in different compositions, or “types,” including:
1. Item P-208—Aggregate Base Course
2. Item P-209—Crushed Aggregate Base Course
3. Item P-211—Lime Rock Base Course
4. Item P-304—Cement Treated Base Course
271
272
Airport Design
5. Item P-306—Econocrete Subbase Course
6. Item P-401—Plant Mix Bituminous Pavements
7. Item P-403—HMA Base Course
P-211, P-304, P-306, P-401, and P-403 are considered stabilized
based courses.
The function of the subbase, when required, is similar to that of
the base course, but since the subbase is further removed from the
area of load application, it is subjected to lower stress intensities. Subbases are typically required when flexible pavement is to be supported by soils of CBR value less than 20.
Flexible pavement subbase courses are available in different
types, including:
1. Item P-154—Subbase Course
2. Item P-210—Caliche Base Course
3. Item P-212—Shell Base Course
4. Item P-213—Sand Clay Base Course
5. Item P-301—Soil Cement Base Course
The subgrade soils are subjected to the lowest loading intensities,
and the controlling stresses are usually at the top of the subgrade
since stress decreases with depth. However, unusual subgrade conditions, such as layered subgrade materials, can alter the location of
controlling stresses.
CBR Method
Prior to 2008, the FAA’s standard method for flexible pavement
design was known as the CBR method. The CBR method was based
on approximation charts that factored in the CBR value of the subgrade and the number and gross weight of equivalent annual departures of the design aircraft. Separate approximation charts were provided by the FAA for different generic aircraft landing gear configurations, and for aircraft greater than 300,000 lb maximum gross
weight, specific individual aircraft. Figure 7-5 provides an illustrative
example of the CBR method.
The example nomograph found in Fig. 7-5 represents the historical method of estimating the base level thickness of flexible pavement for a Boeing 767. The arrow within the nomograph represents
the example for a subgrade with CBR value of 7, a 325,000-lb aircraft
gross weight, and 1200 annual equivalent departures, resulting in a
required base course of 30 in thickness. The nomograph also provides the necessary thickness for the surface layer, at 4 in thick for
critical areas and 3 in thick for noncritical areas, such as pavement
shoulders.
Structural Design of Airport Pavements
CBR
3
4
5
6
7 8 9 10
15
20
30
40
50
40
50
B– 767
Contact area
= 202.46 sq. in.
Dual spacing
= 45 in.
Tandem spacing = 56.00 in.
Gr
weoss
igh airc
5,0
t, L raf
00
B t
3
0
15
0
20
0,0
0,0 ,000
00
00
32
1 in. = 25.4 mm
1 lb. = 0.454 kg
r
pa
e
d
al
nu
An
3
4
5
s
re
tu
1,200
3,000
Thickness hot mix
6,000
Asphalt surfaces
15,000
4–in. Critical areas
25,000
3–in. Noncritical areas
6
7 8 9 10
15
20
30
Thickness, in.
FIGURE 7-5
design.
Example approximation chart, CBR method of flexible pavement
Layered Elastic Design
Originally applied in 1995 specifically for the heaviest of aircraft, the
FAA adopted the layered elastic design (LED) method of flexible
pavement design for all pavements designed to accommodate aircraft greater than 30,000 lb in 2008.
Layered elastic design theory considers the fact that the layers of
pavement that support loads are impacted by both vertical and horizontal strains and stress, as illustrated in Fig. 7-6. To accommodate
the strain, pavement will deflect with the passing of the load. The
magnitude of deflection of a given pavement is a function of its elasticity, E, as measured by Young’s modulus. In addition, the ratio of
transverse to horizontal deflection of a pavement layer, known as
Poisson’s ratio, μ, is considered.
The layered elastic design and cumulative damage failure methods of pavement design are applied in the FAA’s computer pavement
design software, FAARFIELD. FAARFIELD uses a Windows-based
273
274
Airport Design
Wheel load
Horizontal strain and stress
at the bottom of the asphalt
Area of tire contact
Wearing surface
Base course
Subbase
Subgrade
Approximate line of
wheel-load distribution
Vertical subgrade strain
Subgrade support
FIGURE 7-6
Visualization of layer elastic design theory.
interface to allow the user to input initial data concerning the subgrade of the area on which the pavement is to be designed, specifically the Young’s modulus of the subgrade, as well as the expected
fleet mix that will be using the pavement. As illustrated in Fig. 7-7,
FAARFIELD provides the recommended thickness of each layer
within the flexible pavement structure, using recommended pavement
FIGURE 7-7 Example output of FAARFIELD software for flexible pavement
using layered elastic design theory.
Structural Design of Airport Pavements
types (ex. P-401/403 asphalt surfaces), or other user preferred types
listed in this section.
Design of Rigid Pavements
Rigid pavements consist of slabs of PCC placed on a subbase that is
supported on a compacted subgrade. Like flexible pavements, a
properly designed rigid pavement provides a nonskid surface which
prevents the infiltration of water into the subgrade, while providing
structural support to aircraft which use the pavement.
The subbase under rigid pavements provides uniform stable support for the concrete slabs. As a rule, a minimum thickness of 4 in is
required for all subbases under rigid pavements. There are various
types of mixtures which are acceptable for rigid pavement subbases
including:
Item P-154—Subbase Course
Item P-208—Aggregate Base Course
Item P-209—Crushed Aggregate Base Course
Item P-211—Lime Rock Base Course
Item P-301—Soil Cement Base
Item P-304—Cement Treated Base Course
Item P-306—Econocrete Subbase Course
Item P-401—Plant Mix Bituminous Pavements
Item P-403—HMA Base Course
For rigid pavements accommodating aircraft greater than 100,000 lb
maximum gross weight a stabilized subbase is required, which
include items P-304, P-306, P-401, and P-403.
Westergaard’s Analysis
Similar to the CBR method of design for flexible pavements,
prior to 2008, rigid pavement design using nomographs and other
approximation charts based on theories developed by H. M. Westergaard was the FAA standard. Westergaard’s analysis of pavement
design was founded in the mid-1920s and focused on the calculations of stresses and deflections in concrete pavements due to applied
loading.
Westergaard assumed the pavement slab to be a thin plate resting
on a special subgrade which is considered elastic in the vertical direction only. That is, the reaction is proportional to the deflection of the
subgrade p = kz, where z is deflection and k is a soil constant, referred
to as the modulus of subgrade reaction. Other assumptions are that the
concrete slab is a homogeneous, isotropic elastic solid and that the
wheel load of an aircraft is distributed over an elliptical area. Although
275
Airport Design
B–757
3,000
22
20
0
19
18
17
16
15
14
13
650
12
11
600
10
9
550
8
7
500
6
25,000
6,000
15,000
26
26
23
24
25
25
22
23
24
24
22
21
23
23
21
20
22
22
20
21
19
21
19
20
18
20
19
18
17
19
18
17
16
18
17
16
17
15
16
15
16
14
15
14
15
13
14
13
14
12
13
12
13
11
12
12
11
11
10
11
10
10
9
10
9
9
8
9
8
8
8
7
7
7
Slab thickness, in
700
17
22
pci
750
Annual departures
1,200
21
12
5,
00 15
0
0,
00
K = 50
800
100
200
300
500
850
Contact area
= 168.35 sq. in.
Dual spacing
= 34.00 in.
Tandem spacing = 45.00 in.
5,0
2
00 50,0
00
lb
20
5,
00
0,0
0
00
900
Concrete flexural strength, psi
276
FIGURE 7-8 Example design curve for estimating the slab thickness of rigid
pavement using Westergaard’s analysis.
these assumptions do not satisfy theory in a strict sense, the results
compared reasonably with observations. The Westergaard analysis
was used to evaluate stress in a pavement, as well as the deflection of
the slab. For airports, Westergaard developed formulas for stresses
and deflections in the interior of a slab and at an edge of a slab.
The U.S. Army Corps of Engineers applied Westergaard’s formulas toward the creation of approximation charts and design curves.
An example is illustrated in Fig. 7-8.
The arrow found in Fig. 7-8 illustrates an example rigid pavement
design analysis, considering the use of a PCC mixture of flexural strength
of 660 lb/in2, a subgrade with k value 100 lb/in3, for a Boeing 757 design
aircraft with maximum gross weight of 175,000 lb and 6000 annual
equivalent departures, resulting in a design slab thickness of approximately 12 in.
Finite Element Theory
Similar to flexible pavement design, FAARFIELD processes the user
defined fleet mix and E value of the subgrade to determine the thickness requirements of the PCC surface. FAARFIELD recommends
default subbase layers at 6 in thickness. Multiple subbase layers are
recommended for certain subgrades with low E values. Figure 7-9
illustrates an example rigid pavement structure output from FAARFIELD.
FAARFIELD applies finite element theory to estimate the thickness of the PCC surface and any necessary subbase courses. Threedimensional finite element design theory (3D-FE) is similar to layered
Structural Design of Airport Pavements
FIGURE 7-9 Example output of FAARFIELD software for rigid pavement design.
elastic design theory in that it takes into account the Young’s modulus of the subgrade and the materials used in the slab and subbase
courses, and considers a cumulative damage factor in its analysis.
3D-FE design modeling, however, considers the pavement in discrete
sections, rather than a continuous material. This perspective allows
for more accurate estimation of stresses and strain on the edges of the
rigid pavement slabs, which compared to the transverse stress near
the center of the slab, is more critical in rigid pavements.
Joints and Joint Spacing
Slabs of PCC rigid pavement are connected by joints to permit expansion and contraction of the pavement, thereby relieving flexural stresses
due to curling and friction and to facilitate construction. There are three
types of joints: isolation (type A), contraction (type B, C, or E), and
construction (type E) joints. The locations of these joints are illustrated
in Fig. 7-10, with details as to their specifications found in Fig. 7-11.
The function of type A isolation joints is to isolate adjacent pavement slabs and provides space for the expansion of the pavement,
thereby preventing the development of very high compressive
stresses which can cause the pavement to buckle.
Contraction joints are provided to relieve the tensile stresses due to
temperature, moisture, and friction, thereby controlling cracking. If
contraction joints were not installed, random cracking would occur
on the surface of the pavement. The spacing between contraction
joints is dependent on the thickness of the slab, the character of the
277
278
Airport Design
Isolation joint
Detail 1
Non-extruding premolded compressible material
T
Te
3/4" (19 mm)
To the nearest joint but
Te = 1.25 T to nearest 1" (3 mm)
but at least T + 2" (5 mm)
not less than 10" (3 m)
Type A thickened edge
Contraction joints
Detail 2
Detail 2
T/2 ± d/2
T/2 ± d/2
T
T
Tie bar 30" (76 cm) long on 30" (76 cm) centers
Paint and oil one end of dowel
Type B hinged
Type C doweled
Detail 2
T
Type D dummy
Construction joint
Detail 3
T/2 ± d/2
T
Paint and oil one end of dowel
Type E doweled
NOTE:
1. Shaded area is joint sealant.
2. Groove must be formed by sawing.
FIGURE 7-10
Location of rigid pavement joint structures.
aggregate, and whether the slab is plain or reinforced. On the basis of
experience, it has been found that for plain slabs 8 to 10 in thick, the
spacing should be in the range of 15 to 20 ft. For thicker slabs, the
spacing can be increased to 25 ft. Contraction joints may be hinged
(type B), doweled (type C), or considered a “dummy” joint (type D).
The longitudinal and transverse specifications of these joints are in
details in Table 7-6.
Construction joints are required to facilitate construction when
two abutting slabs are placed at different times.
All joints in concrete pavements are sealed with sealing compound
to prevent infiltration of water or foreign material into the joint spaces.
This joint sealant must be capable of withstanding repeated extension
and compression as the pavement changes volume.
Structural Design of Airport Pavements
Sealant material 1/4"–3/8"
(6–10 mm) below surface
1/4" (6 mm) radius
or chamfer
Detail 1
Isolation joint
3/4"±1/8" (19±3 mm)
Rod backup material
Non-extruding premolded compressible
material ASTM D-1751 or 1752
3/4"±1/8" (19±3 mm)
T/4"±1/4" (±6 mm)
Detail 2
Contraction joint
W
Sealant material 1/4"–3/8"
(6–10 mm) below surface
D
1 1/4" (32 mm) minimum
T/4 +/– 1/4" (6 mm)
Rod backup material
Optional (all joints)
1/4" × 1/4" chamfer
Detail 3
Construction joint
Sealant material 1/4"–3/8"
(6–10 mm) below surface
W
D
1 1/4" (32 mm) minimum
Rod backup material
Construction joint between slabs
Longitudinal joint type C or E
Plan view-position of dowels
at edge of joint type C or E
Bar length varies
10" (254 mm) minimum
12" (305 mm) minimum
Bar length varies
Transverse joint
type C or E
NOTES:
1. Sealant reservoir sized to provide proper shape factor, W/D. Field poured and preformed sealants require different
shape factors for optimum performance.
2. Rod backup material must be compatible with the type of sealant used and sized to provide the desired shape factor.
3. Recess sealant 3/8"–1/2" for joints perpendicular to runway grooves.
4. Chamfered edges are recommended when pavements are subject to snow removal equipment of high traffic
volumes.
FIGURE 7-11
Rigid pavement joint structure details.
Dowels are load transfer devices which permit joints to open by
which prevent differential vertical displacement. Usually dowels are
solid, round steel bars, although pipe may also be used. Several different analyses have been proposed for the design of dowels. The
spacing of dowels depends on the thickness of the pavement, modulus of subgrade reaction, and the size of the dowel. Table 7-7 contains
recommendations for dowel sizes and spacings.
Continuously Reinforced Concrete Pavements
A continuously reinforced concrete pavement (CRCP) is one in
which transverse joints have been eliminated (except where the
pavement intersects or abuts existing pavements or structures) and
the longitudinal reinforcing steel is continuous throughout the
length of the pavement. Other than the design of the embedded
279
280
Airport Design
Type
Description
Longitudinal
Transverse
A
Use at intersections
Thickened
edge isolation where dowels are not
suitable and where
joint
pavements abut
structures. Consider
at locations along a
pavement edge where
future expansion is
possible.
B
Hinged
contraction
joint
Not used.
For all contraction joints
in taxiway slabs <9 in
(230 mm) thick. For all
other contraction joints
in slabs <9 in (230 mm)
thick, where the joint is
placed 20 ft (6 m) or less
from the pavement edge.
C
Doweled
contraction
joint
May be considered for
general use. Consider
for use in contraction
joints in slabs >9 in
(230 mm) thick, where
the joint is placed 20 ft
(6 m) or less from the
pavement edge.
May be considered for
general use. Use on the
last three joints from a
free edge, and for three
joints on either side of
isolation joints.
D
Dummy
contraction
joint
For all other contraction
joints in pavement
For all other contraction
joints in pavement.
E
Doweled
construction
joint
Use for construction
Doweled construction
joints excluding isolation joints at all locations
separating successive
joints.
paving operations
(“headers”).
Use at pavement feature
intersections when the
respective longitudinal
axis intersects at an
angle. Use at free edge
of pavements where
future expansion, using
the same pavement
thickness is expected.
TABLE 7-6 Pavement Joint Types
steel within the pavement, thickness design of CRCP is identical to
other rigid pavement types.
The advantages for placing steel in PCC pavements include:
1. Reducing the number of required joints between slabs, resulting in decreased maintenance costs
2. Prolonging service life when pavement is overloaded
3. Reducing pavement deflection
Structural Design of Airport Pavements
Thickness of Slab
6–7 in (150–180 mm)
∗
¾ in (20 mm)
∗
Length
Spacing
18 in (460 mm)
12 in (305 mm)
8–12 in (210–305 mm)
1 in (25 mm)
19 in (480 mm)
12 in (305 mm)
13–16 in (330–405 mm)
1¼ in∗ (30 mm)
20 in (510 mm)
15 in (380 mm)
17–20 in (430–510 mm)
1½ in∗ (40 mm)
20 in (510 mm)
18 in (460 m)
24 in (610 mm)
18 in (460 mm)
21–24 in (535–610 mm)
∗
Diameter
∗
2 in (50 mm)
Dowels noted may be solid bar or high-strength pipe. High-strength pipe must be
plugged on each end with a tight-fitting plastic cap or mortar mix.
TABLE 7-7
Dimensions and Spacing of Steel Dowels in Rigid Pavement
The amount of reinforcing steel required to control volume changes
is dependent primarily on the slab thickness, concrete tensile strength,
and yield strength of the steel. While several procedures have been
proposed for estimating the required amount of steel, experience indicates that it should be approximately 0.6 percent of the gross crosssectional area and that the yield strength should be at least 60,000 lb/
in2. The minimum amount may be determined by Eq. (7-6).
Ps (%) = (1 . 3 − 0 . 2 F )
ft
fs
(7-6)
where Ps = percentage of embedded steel
ft = tensile strength of concrete, lb/in2
fs = allowable working stress in steel, lb/in2
F = coefficient of subgrade friction
The FAA recommends that the cross-sectional area of the reinforcing steel As be obtained by Eq. (7-7).
As =
where
(3 . 7 )L Lt
fs
As = area of steel per foot of width or length, in2
L = length or width of slab, ft
T = thickness of slab, in
fs = allowable tensile stress in steel, lb/in2
Note: To determine the area of steel in metric units:
L should be expressed in meters
t should be expressed in millimeters
fs should be expressed in meganewtons per square meter
The constant 3.7 should be changed to 0.64.
fs will then be in terms of square centimeters per meter.
(7-7)
281
282
Airport Design
The longitudinal embedded steel must also be capable of withstanding the forces generated by the expansion and contraction of the
pavement due to temperature changes. Equation (7-8) determines the
amount of steel required as a function of temperature.
Ps =
where
50 ft
f s − 195T
(7-8)
Ps = embedded steel in percent
ft = tensile strength of concrete, 67 percent of the flexural
strength is recommended
ft = working stress for steel usually taken as 75 percent of
specified minimum yield strength
T = maximum seasonal temperature differential for pavement in degrees Fahrenheit
Longitudinal embedded steel is located at mid-depth or slightly
above mid-depth of the slab.
Transverse embedded steel is recommended for CPRP airport
pavements to control random longitudinal cracking. Equation (7-9) is
used to determine the amount of transverse steel, as a percentage of
the total slab area.
Ps (%) =
where
Ws F
100
2 fs
(7-9)
Ps = embedded steel in percent
Ws = width of slab, in ft
Ft = friction factor of subgrade
fs = allowable working stress in steel, in lb/in2. Yield strength
of 0.75 is recommended
Transverse steel is designed in the same way as tie bars.
Design of Overlay Pavements
Overlay pavements are required when existing pavements are no
longer serviceable due to either deterioration in structural capabilities of a loss in riding quality. They are also required when pavements
must be strengthened to carry greater loads or increased repetitions
of existing aircraft beyond those anticipated in the original design.
Overlays also provide a solution for increased safety. An example
would be to provide improved skid resistance and reduced risk of
hydroplaning.
There are several types of overlay pavements. A concrete pavement
can be overlaid with additional concrete, a bituminous surfacing, or a
Structural Design of Airport Pavements
combination of aggregate base course and a bituminous surfacing.
Likewise, a flexible type of pavement can be overlaid with concrete, a
bituminous surfacing, or the combination of aggregate base course and
a bituminous surfacing. The various types of overlay pavements are
defined as follows:
1. Overlay pavement: The thickness of a rigid or flexible type of
pavement placed on an existing pavement
2. Portland cement concrete overlay: An overlay pavement constructed of portland cement concrete
3. Bituminous overlay: An overlay consisting entirely of a bituminous surfacing
4. Flexible overlay: An overlay consisting of a base course and a
bituminous surfacing
Figure 7-12 provides an illustration of typical pavement overlay
designs.
3" approximately
Bituminous overlay
Bituminous overlay
Original
flexible
pavement
Original
rigid
pavement
Bituminous overlay
on flexible pavement
Bituminous overlay
on rigid pavement
Rigid overlay
Rigid overlay
Original
flexible
pavement
Original
flexible
pavement
Rigid overlay on rigid
pavement
Rigid overlay on flexible
pavement
Rigid overlay
Bituminous leveling
course
Original rigid
pavement
Rigid overlay on rigid pavement
with bituminous leveling course
FIGURE 7-12
Typical overlay pavements.
283
284
Airport Design
The FAA’s FAARFIELD pavement design program includes capabilities for designing airfield pavement overlays. The four types of
overlays considered in FAARFIELD are
1. Hot mix asphalt overlay of existing flexible pavement
2. Concrete overlay of existing flexible pavement
3. Hot mix asphalt overlay of existing rigid pavement
4. Concrete overlay of existing rigid pavement
Based on the thickness and condition of the existing pavement
layers, FAARFIELD estimates the required thickness of the overlay.
Figure 7-13 provides an illustration of FAARFIELD’s output for a
flexible overlay on an existing flexible pavement.
The design of overlays over an existing rigid pavement is slightly
more complex as the condition of the existing rigid pavement plays a
significant role in the required thickness of the overlay. The condition of
the existing rigid pavement is estimated using a structural condition index
(SCI), a value which ranges from 0 to 100, in which 100 representing a
pavement with no visible structural deficiencies and 0 representing total
structural failure. Visible distresses that contribute to a lower SCI include
• Corner breaks
• Longitudinal, transverse, or diagonal cracking
AC_6E_Chapt4
Ex41
Des. Life = 20
Layer
material
Thickness
(in)
Modulus or R
(psi)
P-401/P-403 AC Overlay
7.78
200,000
P-401/P-403 AC Surface
4.00
200,000
P-209 CrAg
10.00
53,948
P-154 UnCrAg
6.00
22,766
Subgrade
CBR = 10.0
15,000
N = 0; Subgrade CDF = 1.00; t = 27.78 in
FIGURE 7-13
pavement.
Design example of flexible overlay on existing flexible
Structural Design of Airport Pavements
• Shattered slab
• Shrinkage cracks
• Spalling (cracking, breaking, or chipping of joint/crack edges)
The SCI is estimated using standard pavement structural condition formulas based on empirical analysis that may be found in general concrete structural evaluation references.
In the case when there are no visible or otherwise degradations in
structural condition, the FAA calls for the estimation of a cumulative
damage factor used (CDFU). For aggregate base layers, CDFU may be
estimated by Eq. (7-10).
CDFU =
LU
when LU < 0 . 75 LD
0 . 75LD
=1
where:
when LU
(7-10)
0 . 75LD
LU = number of years of operation of the existing pavement
until overlay
LD = design life of the existing pavement in years
For rigid pavement bases, CDFU is estimated using the FAARFIELD software, based on the number of years the pavement has
been in use to date. Figure 7-14 illustrates the FAARFIELD output for
estimating CDFU for rigid pavement bases.
FIGURE 7-14 CDFU estimation for rigid pavement bases using FAARFIELD.
285
286
Airport Design
There are several other complexities associated with pavement
overlays, particularly with respect to rigid pavements, that are
beyond the scope of this text. It is strongly recommended that further
study include in-depth review of the FAA Advisory Circular AC
150/5320-6E, “Airfield Pavement Design and Evaluation,” as well as
familiarization with the FAARFIELD software package.
Pavements for Light Aircraft
Pavements for light aircraft are defined as landing areas intended
for personal or other small aircraft engaged in nonscheduled activities, such as recreational, agricultural, or instructional activities, or
small aircraft charter operations. Pavements for light aircraft are
designed to accommodate aircraft with less than 30,000 lb maximum gross weight. In many cases these aircraft will not exceed
12,500 lb. Figure 7-15 illustrates the composition of light aircraft
pavements. Note that, as opposed to pavements for heavier aircraft,
light aircraft pavements do not have critical versus noncritical areas
and as such the surface thickness of pavement is the same through
the paved area.
The FAA FAARFIELD software provides the capability to design
pavements for light aircraft, using a similar procedure for typical flexible and rigid pavements. FAARFIELD requires the CBR or modulus
E value of the subgrade, the aircraft mix, gross weights, and annual
Taxiway
1 Runway and taxiway widths in
accordance with appropriate
advisory circulars.
2 Transverse slopes in accordance
with appropriate advisory circulars.
All pavement areas
same thickness “T”
3 Surfacing, base, PCC, etc., as required.
4 Minimum 12" (30 cm) typical [up to 30" (76 cm)
allowable for slip – formed PCC]
Pavement width
1
3
2
e
Surfac
Base
se
Subba
PCC
Subb
ase
12"
(30 cm)
FIGURE 7-15 Typical sections for light aircraft pavements.
12" 4
(30 cm)
Taxiway
Runway
Structural Design of Airport Pavements
departures of all aircraft. For flexible pavements, FAARFIELD will
estimate the total thickness of the pavement, including a minimum 2
in surface course. For rigid pavements, FAARFIELD will estimate the
slab thickness. In addition FAARFIELD will call for a minimum subbase thickness of 4 in for aircraft weighing 12,500 lb maximum gross
weight or greater.
Other than using flexible or rigid pavement structures, landing
facilities for light aircraft may be turf or an aggregate-turf mixture.
FAARFIELD also has capabilities for estimating the composition of
aggregate-turf mixtures.
Pavement Evaluation and Pavement
Management Systems
A pavement management system (PMS) is a mechanism for providing
consistent, objective, and systematic procedures for evaluating pavement condition and for determining the priorities and schedules for
pavement maintenance and rehabilitation within available resource
and budgeting constraints. The pavement management system can
also be used to maintain records of pavement condition and to provide
specific recommendations for actions which may be required to maintain a pavement network at an acceptable condition while minimizing
the cost associated with pavement maintenance and rehabilitation.
A pavement management system evaluates present pavement
condition and predicts future condition through the use of a pavement condition indicator. By projecting the rate of deterioration in
the pavement condition indicator and adopting some minimum
acceptable level for this indicator, a life-cycle cost analysis can be
performed for various maintenance and rehabilitation alternatives,
and a determination can be made of the optimal time for the application of the most appropriate alternative. The rate of deterioration of a
pavement accelerates with time. By implementing a maintenance or
rehabilitation strategy to upgrade the pavement condition at the
proper time the overall cost of maintenance and rehabilitation can be
minimized. As noted by the FAA, the total annual cost to maintain or
rehabilitate a pavement in relatively poor condition can be 4 to 5 times
that of maintaining or rehabilitating a pavement in relatively good
condition.
An effective PMS for use at airports should include the following
components:
1. A systematic mechanism for regularly collecting, storing, and
retrieving the necessary data associated with pavement use
and condition
2. An objective system for evaluating pavement condition at
regular intervals
287
288
Airport Design
3. Procedures for identifying alternative maintenance and rehabilitation strategies
4. Mechanisms for predicting and evaluating the impact of pavement maintenance and rehabilitation strategies and alternatives
on pavement condition, serviceability, and useful service life
5. Procedures for estimating and comparing the costs of various
strategies and alternatives
6. Techniques for identifying the optimal strategy or alternative
based upon relevant decision criteria
Essential to an effective PMS is the maintenance of a pavement
database which should include
1. Information about the pavement structure, including when it
was originally constructed, the structural components, the
soil conditions, a history of subsequent maintenance and rehabilitation, and the cost of these actions.
2. A record of the airport pavement traffic including the number
of aircraft operations by various types of aircraft using the
pavement over its life.
3. The ability to regularly track pavement condition, including
measures of pavement distress and the causes of distress. A
pavement rating system should be developed based upon the
quantity, severity, and type of distress affecting the pavement
surface condition. This rating system measures pavement
surface performance and has implications for structural performance. The periodic collection of condition-rating data is
essential to tracking pavement performance
As part of an effective PMS, the evaluation of airport pavements
should be a methodical process, which includes a thorough review of
construction data and usage history, routine site inspections, and
pavement sampling and testing. Types of sampling and testing procedures include: direct sampling, nondestructive testing (NDT),
ground penetrating radar, and infrared thermography.
References
1. Airport Pavement Design and Evaluation, Advisory Circular AC 150/5320-6E,
Federal Aviation Administration, Washington, D.C., 2008.
2. Airport Pavement Design and Evaluation, Advisory Circular AC 150/5320-6D
includes changes 1 through 4, Federal Aviation Administration, Washington,
D.C., 2006.
3. FAA Finite Element Design Procedure for Rigid Pavements, FAA AR-07/33, Federal
Aviation Administration, Washington, D.C., 2007.
4. “Evolution of Concrete Road Design in the United States,” Pavement Digest,
Vol. 1. Issue 2, 2005.
Structural Design of Airport Pavements
5. Kawa, Brill, Hayhoe, FAARFIELD—New FAA Airport Thickness Design Software,
manuscript presenting for the 2007 FAA Worldwide Airport Technology
Transfer Conference, Atlantic City, N.J., April 2007.
6. “A Design Procedure for Continuously Reinforced Concrete Pavements for
Highways,” ACI Subcommittee VII, Title No. 69-32, Vol. 69, pp. 309–319, Journal
of the American Concrete Institute, Detroit, Mich., 1972.
7. Aerodrome Design Manual, Part 3, Pavements, Document No. 9157-AN/901, 2d
ed., International Civil Aviation Organization, Montreal, Canada, 1983.
8. Aerodromes, Annex 14 to the Convention on International Civil Aviation, Vol. 1,
Aerodrome Design and Operations, International Civil Aviation Organization,
Montreal, Canada, 1990.
9. Aerodromes, Annex 14 to the Convention on International Civil Aviation,
Vol. 2, Heliports, International Civil Aviation Organization, Montreal,
Canada, 1990.
10. Aircraft Loading on Airport Pavements, ACN-PCN, Aircraft Classification Numbers
for Commercial Turbojet Aircraft, Aerospace Industries Association of America,
Inc., Washington, D.C., 1983.
11. “Aircraft Pavement Loading: Static and Dynamic,” R. C. O’Massey, Research
in Airport Pavements, Special Report No. 175, Transportation Research Board,
Washington, D.C., 1978.
12. Airfield Pavement Requirements for Multi-Wheel Heavy Gear Loads, Report No.
FAA-RD-70-77, Federal Aviation Administration, Washington, D.C., 1971.
13. Airport Design, Advisory Circular AC 150/5300-13, Federal Aviation
Administration, Washington, D.C., 1989.
14. “Analysis of Stresses in Concrete Pavements due to Variations of Temperature,”
H. M. Westergaard, Proceedings, 6th Annual Meeting, Highway Research
Board, Washington, D.C.
15. “Applications of the Results of Research to the Structural Design of Pavements,”
E. F. Kelley, Journal of the American Concrete Institute, Detroit, Mich., 1939.
16. “Characterization of Subgrade Soils in Cold Regions for Pavement Design
Purposes,” A. T. Bergan and C. L. Monismith, Highway Research Record, No.
431, Highway Research Board, Washington, D.C., 1973.
17. Computer Aided Design for Flexible Airfield Pavements, Computer Program FAD
(FAA Version F806FAA), U.S. Army Corps of Engineers, Waterways Experiment
Station, Vicksburg, Miss., 1992.
18. Computer Aided Design for Rigid Airfield Pavements, Computer Program RAD
(FAA Version R805FAA), U.S. Army Corps of Engineers, Waterways Experiment
Station, Vicksburg, Miss., 1992.
19. Computer Aided Evaluation for Airfield Pavements, Computer Program PCN, U.S.
Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Miss.,
1992.
20. Computer Program for Airport Pavement Design, R. G. Packard, Portland Cement
Association, Skokie, Ill., 1967.
21. Computer Program Supplement to Thickness Design Asphalt Pavements for Air
Carrier Airports, Manual Series, No. MS-11A, The Asphalt Institute, Lexington,
Ky., 1987.
22. Design and Construction and Behavior under Traffic of Pavement Test Sections,
Report No. FAA-RD-73-198-I, Federal Aviation Administration, Washington,
D.C., 1974.
23. Design and Construction, Continuously Reinforced Joint and Crack Sealing Materials
and Practices, NCHRP Report, Report No. 38, National Cooperative Highway
Research Program, Highway Research Board, Washington, D.C., 1967.
24. Design and Construction of Airport Pavements on Expansive Soils, Report No.
FAA-RD-76-66, Federal Aviation Administration, Washington, D.C., 1976.
25. Design and Construction of MESL, Report No. FAA-RD-73-198-III, Federal
Aviation Administration, Washington, D.C., 1974.
26. “Design Considerations for Multi Wheel Aircraft,” W. R. Barker and C. R.
Gonzalez, International Air Transportation, Proceedings of the 22nd Conference
on International Air Transportation, American Society of Civil Engineers, New
York, N.Y., 1992.
289
290
Airport Design
27. Design Manual for Continuously Reinforced Concrete Pavements, Report No.
FAA-RD-74-33-III, Federal Aviation Administration, Washington, D.C., 1974.
28. Design of Civil Airfield Pavement for Seasonal Frost and Permafrost Conditions,
Report No. FAA-RD-74-30, Federal Aviation Administration, Washington, D.C.,
1974.
29. Design of Concrete Airport Pavement, R. G. Packard, Engineering Bulletin,
Portland Cement Association, Skokie, Ill., 1973.
30. Design of Flexible Airfield Pavements for Multiple-Wheel Landing Gear Assemblies,
Report No. 2, Analysis of Existing Data, Technical Memorandum 3-349, U.S. Army
Corps of Engineers, Waterways Experiment Station, Vicksburg, Miss., 1955.
31. “Design of Pavement with High Quality Structural Layers,” G. M. Hammitt,
Research in Airport Pavements, Special Report, No. 175, Transportation
Research Board, Washington, D.C., 1978.
32. Economic Analysis of Airport Pavement Rehabilitation Alternatives, Report No.
FAA-RD-81-78, Federal Aviation Administration, Washington, D.C., 1981.
33. “Effect of Dynamic Loads on Airport Pavements,” R. H. Ledbetter, Research in
Airport Pavements, Special Report, No. 175, Transportation Research Board,
Washington, D.C., 1978.
34. ELSYM5—Computer Program for Determining Stresses and Deformation in a Five
Layer Elastic System, G. Ahlborn, University of California, Berkeley, Calif.,
1972.
35. “Equivalent Passages of Aircraft with Respect to Fatigue Distress of Flexible
Airfield Pavements,” J. A. Deacon, Proceedings, Association of Asphalt Paving
Technologists, 1971.
36. Field Survey and Analysis of Aircraft Distribution on Airport Pavements, Report No.
FAA-RD-74-36, Federal Aviation Administration, Washington, D.C., 1975.
37. Flexible Airfield Pavements, Technical Manual, TM 5-825-2, U.S. Army Corps of
Engineers, A. G. Publication Center, St. Louis, Mo., 1978.
38. Full-Depth Asphalt Pavements for General Aviation, Information Series, No. IS-154,
The Asphalt Institute, Lexington, Ky., 1973.
39. Geomechanics Computing Programme, N. 1, Computer Programmes for Circle and
Strip Loads on Layered Anisotropic Media, W. J. Harrison, C. M. Gerrard, and
L. J. Wardel, Division of Applied Geomechanics, SCIRO, Australia, 1972.
40. Guidelines and Procedures for Maintenance of Airport Pavements, Advisory Circular
AC 150/5380-6, Federal Aviation Administration, Washington, D.C., 1982.
41. Hot Mix Asphalt Paving Handbook, Advisory Circular AC 150/5370-14, Federal
Aviation Administration, Washington, D.C., 1991.
42. “Influence Charts for Rigid Pavements,” G. Pickett and G. K. Ray, Transactions,
American Society of Civil Engineers, Vol. 116, pp. 49–73, New York, N.Y.,
1951.
43. “Layered Systems Under Normal Surface Loads,” M. G. Peutz, H. P. M. van
Kempen, and A. Jones, Highway Research Record, No. 228, Highway Research
Board, Washington, D.C., 1968.
44. Measurement, Construction, and Maintenance of Skid Resistant Airport Pavement
Surfaces, Advisory Circular AC 150/5320-12B, Federal Aviation Administration,
Washington, D.C., 1991.
CHAPTER
8
Airport Lighting,
Marking, and
Signage
Introduction
Visual aids assist the pilot on approach to an airport, as well as navigating around an airfield and are essential elements of airport infrastructure. As such, these facilities require proper planning and precise
design.
These facilities may be divided into three categories: lighting,
marking, and signage. Lighting is further categorized as either approach
lighting or surface lighting. Specific lighting systems described in this
chapter include
1. Approach lighting
2. Runway threshold lighting
3. Runway edge lighting
4. Runway centerline and touchdown zone lights
5. Runway approach slope indicators
6. Taxiway edge and centerline lighting
The proper placement of these systems is described in this chapter but no attempt has been made to describe in detail the hardware
or its installation. Airfield marking and signage includes
1. Runway and taxiway pavement markings
2. Runway and taxiway guidance sign systems
291
292
Airport Design
Airfield lighting, marking, and signage facilities provide the following
functions:
1. Ground to air visual information required during landing
2. The visual requirements for takeoff and landing
3. The visual guidance for taxiing
In the United States, the Federal Aviation Administration provides
guidance for designing standard airfield lighting, marking, and signage, through published Advisory Circulars. These Advisory Circulars are frequently updated. The standards described in this text are
current as of 2007. Current advisory circulars may be found at the
FAA’s website at http://www.faa.gov.
The Requirements for Visual Aids
Since the earliest days of flying, pilots have used ground references for
navigation when approaching an airport, just as officers on ships at
sea have used landmarks on shore when approaching a harbor. Pilots
need visual aids in good weather as well as in bad weather and during
the day as well as at night.
In the daytime there is adequate light from the sun, so artificial
lighting is not usually required but it is necessary to have adequate
contrast in the field of view and to have a suitable pattern of brightness so that the important features of the airport can be identified and
oriented with respect to the position of the aircraft in space. These
requirements are almost automatically met during the day when the
weather is clear.
The runway for conventional aircraft always appears as a long narrow strip with straight sides and is free of obstacles. It can therefore be
easily identified from a distance or by flying over the field. Therefore,
the perspective view of the runway and other identifying reference
landmarks are used by pilots as visual aids for orientation when they
are approaching the airport to land. Experience has demonstrated that
the horizon, the runway edges, the runway threshold, and the centerline of the runway are the most important elements for pilots to see.
In order to enhance the visual information during the day, the runway is painted with standard marking patterns. The key elements in
these patterns are the threshold, the centerline, the edges, plus multiple parallel lines to increase the perspective and to define the plane of
the surface.
During the day when visibility is poor and at night, the visual
information is reduced by a significant amount over the clear weather
daytime scene. It is therefore essential to provide visual aids which
will be as meaningful to pilots as possible.
Airport Lighting, Marking, and Signage
The Airport Beacon
Beacons are lighted to mark an airport. They are designed to produce
a narrow horizontal and vertical beam of high-intensity light which is
rotated about a vertical axis so as to produce approximately 12 flashes
per minute for civil airports and 18 flashes per minute for military
airports [28]. The flashes with a clearly visible duration of at least 0.15 s
are arranged in a white-green sequence for land airports and a whiteyellow sequence for landing areas on water. Military airports use a
double white flash followed by a longer green or yellow flash to differentiate them from civil airfields. The beacons are mounted on top
of the control tower or similar high structure in the immediate vicinity
of the airport.
Obstruction Lighting
Obstructions are identified by fixed, flashing, or rotating red lights or
beacons. All structures that constitute a hazard to aircraft in flight or
during landing or takeoff are marked by obstruction lights having a
horizontally uniform intensity duration and a vertical distribution
design to give maximum range at the lower angles (1.5° to 8°) from
which a colliding approach would most likely come. The criteria for
determining which structures need to be lighted are published by the
FAA [18, 19].
The Aircraft Landing Operation
An aircraft approaching a runway in a landing operation may be
visualized as a sequence of operations involving a transient body
suspended in a three-dimensional grid that is approaching a fixed
two-dimensional grid. While in the air, the aircraft can be considered
as a point mass in a three-dimensional orthogonal coordinate system
in which it may have translation along three coordinate directions
and rotation about three axes. If the three coordinate axes are aligned
horizontal, vertical, and parallel to the end of the runway, the directions of motion can be described as lateral, vertical, and forward. The
rotations are normally called pitch, yaw, and roll, for the horizontal,
vertical, and parallel axes, respectively. During a landing operation,
pilots must control and coordinate all six degrees of freedom of the
aircraft so as to bring the aircraft into coincidence with the desired
approach or reference path to the touchdown point on the runway.
In order to do this, pilots need translation information regarding
the aircraft’s alignment, height, and distance, rotation information
regarding pitch, yaw, and roll, and information concerning the rate of
descent and the rate of closure with the desired path. The glide path,
height, time, and distance relationships during a typical landing are
shown in Fig. 8-1.
293
294
Airport Design
Runway
Touch-down point
lide
per g
slope
limit
p
3.0° u
Runway threshold
e slope
2.5° glid
100'
1000'
200'
300'
400'
1290'
(6 sec)
3580' (16 sec)
5870' (27 sec)
8160' (37 sec)
Time basis: 150 mph = 220 f.p.s.
FIGURE 8-1
Glide slope, height, distance, and time relationships.
Alignment Guidance
Pilots must know where their aircraft is with respect to lateral displacement from the centerline of the runway. Most runways are from
75 to 200 ft wide and from 3000 to 12,000 ft long. Thus any runway is a
long narrow ribbon when first seen from several thousand feet above.
The predominant alignment guidance comes from longitudinal lines
that constitute the centerline and edges of the runway. All techniques,
such as painting, lighting, or surface treatment that develop contrast
and emphasize these linear elements are helpful in providing alignment information.
Height Information
The estimation of the height above ground from visual cues is one of
the most difficult judgments for pilots. It is simply not possible to
provide good height information from an approach lighting system.
Consequently the best source of height information is the instrumentation in the aircraft. However, use of these instruments often requires
the availability of precision ground or satellite based navigation technologies. Many airports have no such technologies, and at others
only provide lateral approach guidance to certain runways. Consequently two types of ground-based visual aids defining the desired
glide path have been developed. These are known as the visual
approach slope indicator (VASI) and the precision approach path
indicator (PAPI) which are discussed later in this chapter.
Several parameters influence how much a pilot can see on the
ground. One of these is the cockpit cutoff angle. This is the angle
between the longitudinal axis of the fuselage and an inclined plane
below which the view of the pilot is blocked by some part of the aircraft,
indicated by α in Fig. 8-2. Normally the larger the angle α, the more
the pilot can see of the ground. Also important is the pitch angle, β,
Airport Lighting, Marking, and Signage
β
Horizontal
Visual cone
VR
G
φ
lage
axis
h
e
lop
s
lide
Fuse
α
θ
α−β
H
Runway
FIGURE 8-2 Visual parameters: ϕ = glide slope angle, α = cockpit cutoff
angle, β = pitch angle, VR = visual range, H = horizontal segment of visual
range, h = height of glide slope above the runway, and θ = angle formed by
VR with the horizontal.
of the fuselage axis during the approach to the runway. Few aircraft
approach a runway with the fuselage angle horizontal; they are either
pitched up or down. The larger the angle β (in a pitch-up attitude),
the larger must be the angle α to have adequate over-the-nose vision.
Approach speed has a profound influence on the angle β. As an
example, for some aircraft β can be decreased by about 1° with each
5 kn increase in speed above the reference approach speed.
In Fig. 8-2, VR is the visual range or the maximum distance a pilot
can see and some height above the runway h. The horizontal segment
of the ground that a pilot can see is H. According to Fig. 8-2,
H = VR cos Θ − h cot (α − β)
(8-1)
and also
sin Θ =
h
VR
(8-2)
Note from Eq. (8-1) that for a fixed value of VR the ground segment H increases as the height h of the eyes of a pilot above the ground
decreases. Typical values of α range from 11° to 16° and typical values
of β are ± 0.5°.
It has been found through experience that 3 s is approximately
the minimum reaction time for a pilot to cause the aircraft to react
after sighting a visual aid [28]. If a minimum of 3 s is necessary for
perception, pilot action, aircraft response, and checking the response,
and if the approach speed of the aircraft is 150 mi/h (220 ft/s), then
the minimum horizontal segment on the ground should not be less
than 660 ft. Using Eq. (8-1) with the glide slope angle, ϕ, of 2.5° and a
295
296
Airport Design
value of α − β of 12° results in H being about 200 ft when h is 200 ft.
However, when h is 100 ft, H is 687 ft. Consequently, lighting systems
designed to aid in aircraft approaching to land on a runway have
been designed to provide optimal visual guidance when aircraft are
at relatively low altitudes on approach, and are angled to be consistent with the downward approach angle of arriving aircraft.
Approach Lighting
Approach lighting systems (ALS) are designed specifically to provide
guidance for aircraft approaching a particular runway under nighttime or other low-visibility conditions. While under nighttime conditions it may be possible to view approach lighting systems from several
miles away, under other low-visibility conditions, such as fog, even
the most intense ALS systems may only be visible from as little as
2500 ft from the runway threshold.
Studies of the visibility in fog [3] have shown that for a visual range
of 2000 to 2500 ft it would be desirable to have as much as 200,000 candelas (cd) available in the outermost approach lights where the slant
range is relatively long. Under these same conditions the optimum
intensity of the approach lights near the threshold should be on the
order of 100 to 500 cd. A transition in the intensity of the light that is
directed toward the pilot is highly desirable in order to provide the best
visibility at the greatest possible range and to avoid glare and the loss
of contrast sensitivity and visual acuity at short range.
System Configurations
The configurations which have been adopted are the Calvert system
[3] shown in Fig. 8-3 which has been widely used in Europe and other
parts of the world, the ICAO category II and category III system shown
in Fig. 8-4, and the four system configurations which have been adopted
by the FAA in the United States shown in Fig. 8-5. The FAA publishes
criteria for the establishment of the approach lighting systems [13]
and other navigation facilities at airports [6]. Approach lights are normally mounted on frangible pedestals of varying height to improve
the perspective of the pilot in approaching a runway.
The first approach lighting system was known as the Calvert system. In this system, developed by E. S. Calvert in Great Britain in 1949,
includes a line of single bulb lights spaced on 100-ft centers along the
extended runway centerline and six transverse crossbars of lights of
variable length spaced on 500-ft centers, for a total length of 3000 ft.
The Calvert system was the first approach lighting system to be certified by ICAO, and is also commonly known as the ICAO category I
approach lighting system. An illustration of the Calvert system is found
in Fig. 8-3. The Calvert system is still used in developing countries.
Airport Lighting, Marking, and Signage
3000'
500'
100'
RUNWAY THRESHOLD
FIGURE 8-3
CENTRE LINE LIGHTS
HORIZON BAR LIGHTS
Calvert approach lighting system.
For operations in very poor visibility, ICAO has certified a modification of the Calvert system, known as the ICAO category II system.
The variation calls for a higher lighting intensity to the inner 300 m
of the system closest to the runway threshold. The category II and
category III system adopted by ICAO shown in Fig. 8-4 consists of two
lines of red bars on each side of the runway centerline and a single line
of white bars on the runway centerline both at 30 m intervals and both
extending out 300 m from the runway threshold. In addition, there are
two longer bars of white light at a distance of 150 and 300 m from the
runway threshold, and a long threshold bar of green light at the runway threshold. ICAO also recommends that the longer bars of white
light also be placed at distances of 450, 500, and 750 m from the runway threshold if the runway centerline lights extend out that distance
as shown in Fig. 8-4.
The ALSs currently certified by the FAA for installation in the
United States consist of a high-intensity ALS with sequenced flashing
lights (ALSF-2), which is required for category II and category III
precision approaches, a high-intensity approach lighting system with
300 m
150 m
600 m
150 m
150 m
150 m
ICAO
CAT II–III
Red Lights
White Lights
Green Lights
FIGURE 8-4 ICAO CAT II-III approach lighting system.
297
298
Airport Design
sequenced flashing lights (ALSF-1), and three medium-intensity ALSs
(MALSR, MALS, MALSF).
In each of these systems there is a long transverse crossbar located
1000 ft from the runway threshold to indicate the distance from the
runway threshold. In these systems roll guidance is provided by
crossbars of white light 14 ft in length, placed at either 100- or 200-ft
centers on the extended runway centerline. The 14-ft crossbars consist
of closely spaced five-bulb white lights to give the effect of a continuous
bar of light.
The high-intensity ALS is 2400 ft long (some are 3000 ft long) with
various patterns of light located symmetrically about the extended
runway centerline and a series of sequenced high-intensity flashing
lights located every 100 ft on the extended runway centerline for the
outermost 1400 ft. In the high-intensity ALSs the 14-ft crossbars of
five-bulb white light are placed at 100-ft intervals and in the mediumintensity ALSs these crossbars of white light are placed at 200-ft intervals both for a distance of 2400 ft from the runway threshold on the
extended runway centerline. The high-intensity ALSs have a long
crossbar of green lights at the edge of the runway threshold. The
ALSF-2 system, shown in Fig. 8-5a, has two additional crossbars consisting of three-bulb white light crossbars which are placed symmetrically about the runway centerline at a distance of 500 ft from the runway
threshold and two additional three-bulb red light crossbars are placed
symmetrically about the extended runway centerline at 100-ft intervals for the inner 1000 ft to delineate the edges of the runway surface.
The ALSF-1 system, shown in Fig. 8-5b, has two additional crossbars
consisting of five-bulb red light crossbars which are placed symmetrically about the runway centerline at a distance of 100 ft from the runway threshold to delineate the edge of the runway and two additional
three-bulb red light crossbars placed symmetrically about the extended
runway centerline at 200 ft from the runway threshold.
The MALSR system, shown in Fig. 8-5c, is a 2400-ft mediumintensity ALS with runway alignment indicator lights (RAILs). The
inner 1000 ft of the MALSR is the MALS portion of the system and the
outer 1400 ft is the RAIL portion of the system. The system has
sequential flashing lights for the outer 1000 ft of the system. It is recommended for category I precision approaches. The simplified short
approach lighting system (SSALR) has the same configuration as the
MALSR system.
At smaller airports where precision approaches are not required,
a medium ALS with sequential flashers (MALSF) or with sequenced
flashers (MALS) is adequate. The system is only 1400 ft long compared to a length of 2400 ft for a precision approach system. It is
therefore much more economical, an important factor at small airports. The MALSF, similar to the MALSR shown in Fig. 8-5d, is a short
approach medium-intensity ALS but the sequenced flashers replace
Airport Lighting, Marking, and Signage
2400'–3000'
500'
500'
400'
1000'–1600'
ALSF-2
Sequential Flashers
Red Lights
White Lights
Green Lights
(a)
2400'–3000'
500'
500'
400'
1000'–1600'
ALSF-1
Sequential Flashers
Red Lights
White Lights
Green Lights
(b)
FIGURE 8-5a–d
Approach lighting system configurations. (Continued)
299
300
Airport Design
2400'
500'
500'
400'
1000'
MALSR
SSALR
Sequential Flashers
Red Lights
White Lights
(c)
1400'
500'
500'
400'
MALSF
Sequential Flashers
Red Lights
White Lights
(d)
FIGURE 8-5a–d
Approach lighting system configurations.
the runway alignment indicator lights and these are only provided in the
outermost 400 ft of the 1400-ft system to improve pilot recognition of
the runway approach in areas where there are distracting lights in the
vicinity of the airport. The MALS system does not have the runway
alignment indicator lights or the sequential flashers.
At international airports in the United States, the 2400-ft ALSs are
often extended to a distance of 3000 ft to conform to international
specifications.
Airport Lighting, Marking, and Signage
Sequenced-flashing high-intensity lights are available for airport
use and are installed as supplements to the standard approach lighting
system at those airports where very low visibilities occur frequently.
These lights operate from the stored energy in a capacitor which is discharged through the lamp in approximately 5 ms and may develop as
much as 30 million cd of light. They are mounted in the same pedestals
as the light bars. The lights are sequence-fired, beginning with the unit
farthest from the runway. The complete cycle is repeated every 2 s. This
results in a brilliant ball of light continuously moving toward the runway. Since the very bright light can interfere with the eye adaptation of
the pilot, condenser discharge lamps are usually omitted in the 1000 ft
of the approach lighting system nearest the runway.
Visual Approach Slope Aids
Visual approach slope aids are lighting systems designed to provide
a measure of vertical guidance to aircraft approaching a particular
runway. The principle of these aids is to provide color-based identification to the pilot indicating their variation from a desired altitude
and descent rate while on approach. The two most common visual
approach slope aids are the visual approach slope indicator (VASI),
and the precision approach path indicator (PAPI).
Visual Approach Slope Indicator
The visual approach slope indicator (VASI) is a system of lights which
acts as an aid in defining the desired glide path in relatively good
weather conditions. VASI lighting intensities are designed to be visible from 3 to 5 mi during the day and up to 20 mi at night.
There are a number of different VASI configurations depending
on the desired visual range, the type of aircraft, and whether large
wide bodied aircraft will be using the runway. Each group of lights
transverse to the direction of the runway is referred to as a bar. The
downwind bar is typically located between 125 and 800 ft from the
runway threshold, each subsequent bar is located between 500 and
1000 ft from the previous bar. A bar is made up of one, two, or three
light units, referred to as boxes. The basic VASI-2 system, illustrated in
Fig. 8-6, is a two-bar system consisting of four boxes. The bar that is
nearest to the runway threshold is referred to as the downwind bar,
and the bar that is farthest from the runway threshold is referred to as
the upwind bar. As illustrated in Fig. 8-6, if pilots are on the proper
glide path, the downwind bar appears white and the upwind bar
appears red; if pilots are too low, both bars appear red; and if they are
too high both bars appear white.
In order to accommodate large wide bodied aircraft where the
height of the eye of the pilot is much greater than in smaller jets, a third
upwind bar is added. For wide bodied aircraft the middle bar becomes
301
302
Airport Design
Far Bar
= Red
Near Bar
= White
Below Glide Path
On Glide Path
Above Glide Path
FIGURE 8-6 Two bar VASI system (FAA/AIM ).
the downwind bar and the third bar is the upwind bar. In other words,
pilots of large wide bodied aircraft ignore the bar closest to the runway threshold and use the other two bars for visual reference. The
location of the lights for VASI-6 systems is shown in Fig. 8-7.
The more common systems in use in the United States are the
VASI-2, VASI-4, VASI-12, and VASI-16. VASI systems are particularly
useful on runways that do not have an instrument landing system or
for aircraft not equipped to use an instrument landing system.
Precision Approach Path Indicator
The FAA presently prefers the use of another type of visual approach
indicator called the precision approach path indicator (PAPI) [20]. This
system gives more precise indications to the pilot of the approach
path of the aircraft and utilizes only one bar as opposed to the minimum of two required by the VASI system. A schematic diagram of the
PAPI system is shown in Fig. 8-8.
The system consists of a unit with four lights on either side of the
approach runway. By utilizing the color scheme indicated on Fig. 8-8,
the pilot is able to ascertain five approach angles relative to the proper
glide slope as compared with three with the VASI system. One of the
problems with the VASI system has been the lack of an immediate
transition from one color indication to another resulting in shades of
colors. The PAPI system resolves this problem by providing an instant
transition from one color indication to another as a reaction to the
Far Bar
Middle Bar
Near Bar
Below Both
Glide Paths
On Lower
Glide Path
FIGURE 8-7 Three bar VASI-6 system.
On Upper
Glide Path
Above Both
Glide Paths
Airport Lighting, Marking, and Signage
High
(More Than
3.5 Degrees)
Slightly High
(3.2 Degrees)
On Glide Path
(3 Degrees)
Slightly Low
(2.8 Degrees)
Low
(Less Than
2.5 Degrees)
White
Red
FIGURE 8-8 Precision approach path indicator (PAPI) system.
descent path of the aircraft. An advantage of the system is that it is a
one-bar system as opposed to the two-bar VASI system. This results in
greater operating and maintenance cost economies, and eliminates the
need for the pilot to look at two bars to obtain glide slope indications.
Threshold Lighting
During the final approach for landing, pilots must make a decision to
complete the landing or “execute a missed approach.” The identification of the threshold is a major factor in pilot decisions to land or not
to land. For this reason, the region near the threshold is given special
lighting consideration. The threshold is identified at large airports by
a complete line of green lights extending across the entire width of
the runway, as shown earlier in Fig. 8-5, and at small airports by four
green lights on each side of the threshold. The lights on either side of
the runway threshold may be elevated. Threshold lights in the direction of landing are green but in the opposite direction these lights are
red to indicate the end of the runway.
Runway Lighting
After crossing the threshold, pilots must complete a touchdown and
roll out on the runway. The runway visual aids for this phase of landing are be designed to give pilots information on alignment, lateral
displacement, roll, and distance. The lights are arranged to form a
visual pattern that pilots can easily interpret.
At first, night landings were made by floodlighting the general
area. Various types of lighting devices were used, including automobile headlights, arc lights, and search lights. Boundary lights were
added to outline the field and to mark hazards such as ditches and
fences. Gradually, preferred landing directions were developed, and
special lights were used to indicate these directions. Floodlighting
was then restricted to the preferred landing directions, and runway
edge lights were added along the landing strips. As experience was
303
304
Airport Design
developed, the runway edge lights were adopted as visual aids on a
runway. This was followed by the use of runway centerline and touchdown zone lights for operations in very poor visibility. FAA Advisory
Circular 150/5340-30C provides guidance for the design and installation of runway and taxiway lighting systems. Those planning and
designing such systems should refer to the latest changes to this Advisory Circular, commonly found at http://www.faa.gov.
Runway Edge Lights
Runway edge lighting systems outline the edge of runways during
nighttime and reduced visibility conditions. Runway edge lights are
classified by intensity, high intensity (HIRL), medium intensity (MIRL),
and low intensity (LIRL). LIRLs are typically installed on visual runways and at rural airports. MIRLs are typically installed on visual
runways at larger airports and on nonprecision instrument runways,
HIRLs are installed on precision-instrument runways.
Recommended standards for the design and installation of runway edge lighting systems are published by the FAA [21] and are
contained in ICAO Annex 14 [1]. These light fixtures are usually
elevated units but semiflush lights are permitted. Each unit has a
specially designed lens which projects two main light beams down
the runway. Elevated runway lights are mounted on frangible fittings
and project no more than 30 in above the surface on which they are
installed. They are located along the edge of the runway not more than
10 ft from the edge of the full-strength pavement surface. The longitudinal spacing is not more than 200 ft. Runway edge lights are white,
except that the last 2000 ft of an instrument runway in the direction of
aircraft operations these lights are yellow to indicate a caution zone.
A typical layout of low-intensity and medium-intensity runway edge
lights is shown in Fig. 8-9, and a typical layout of HIRLs are illustrated in Fig. 8-10. If the runway threshold is displaced, but the area
that is displaced is usable for takeoffs and taxiing, the runway edge
lights in the displaced area in the direction of aircraft operations are
red, as shown in Fig. 8-11.
Runway Centerline and Touchdown Zone Lights
As an aircraft traverses over the approach lights, pilots are looking at
relatively bright light sources on the extended runway centerline.
Over the runway threshold, pilots continue to look along the centerline, but the principal source of guidance, namely, the runway edge
lights, has moved far to each side in their peripheral vision. The result
is that the central area appears excessively black, and pilots are virtually flying blind, except for the peripheral reference information, and
any reflection of the runway pavement from the aircraft’s landing
lights. Attempts to eliminate this “black hole” by increasing the intensity of runway edge lights have proven ineffective. In order to reduce
Airport Lighting, Marking, and Signage
200' max
2' min
10' max
10'
ctr to ctr
2' min
10' max
10'
ctr to ctr
400' max
ax
W
20
0'
m
DETAIL A: Threshold/Runway End Lights
Installed with LIRL’s or MIRL’s
DETAIL A
200' max
G R
200' max
W
W
W
20
G R
B W
W
B
W
taxiway
B
B
W
NOTES:
1. Install six threshold lights on visual runways.
2. Install eight threshold lights on instrument runways.
3. For intersections, uniform spacing is maintained by
installing a single elevated edge light on the runway
opposite the missing light position.
4. Gaps between lights on a single side of the runway must
not exceed 400 ft.
5. Markings are for information only, refer to AC 150/5340-1
for appropriate runway markings.
FIGURE 8-9 Low-intensity runway edge lighting specifications (Federal Aviation
Administration).
the black hole effect and provide adequate guidance during very
poor visibility conditions, runway centerline and touchdown zone
lights are typically installed in the pavement. An illustration of runway centerline lighting is provided in Fig. 8-12.
These lights are usually installed only at those airports which are
equipped for instrument operations. These lights are required for ILS
category II and category III runways and for category I runways used
for landing operations below 2400 ft runway visual range. Runway centerline lights are required on runways used for takeoff operations below
1600 ft runway visual range. Although not required, runway centerline
lights are recommended for category I runways greater than 170 ft in
width or when used by aircraft with approach speeds over 140 kn.
When there are displaced thresholds, the centerline lights are
extended into the displaced threshold area. If the displaced area is not
used for takeoff operations, or if the displaced area is used for takeoff
operations and is less than 700 ft in length, the centerline lights are
blanked out in the direction of landing. For displaced thresholds greater
than 700 ft in length or for displaced areas used for takeoffs, the centerline lights in the displaced area must be capable of being shut off during
landing operations.
305
306
200' max
200' max
W
W
DETAIL A
200' max
G
R
W Y
W
W Y
W
20
L
G
R
runway
B W Y
W
W Y
taxiway
B
W
200' max
B
2' min
10' max
10'
ctr to ctr
10'
ctr to ctr
DETAIL A: Threshold/Runway End Lights
installed with HIRL’s
FIGURE 8-10
W
W
B
2' min
10' max
NOTES:
Install six threshold lights on visual runways.
1. Install eight threshold lights on instrument runways.
2. Install yellow runway edge lights on the last 2000 ft. or
3. One-half of runway length, whichever is less, on an
instrument runway.
4. Runway edge lights are uniformly spaced and
symmetrical about the runway centerline.
5. Maintain uniform spacing across intersections by
installing a single edge light on the runway opposite
the intersection.
6. For HIRL’s when the gap exceeds 400 ft. install an
in-pavement light fixture to maintain uniform spacing.
High-intensity runway edge lighting specifications (Federal Aviation Administration).
Take off Start
LDA Stop End
Landing Threshold
8
G UNI
R
Y
R
Y
R
Y
G Y
W Y
R
Y
G Y
W Y
W Y
B
W Y
2
R
1
20
L
R
G UNI
B
B
B
B
NOTES:
1. Full runway safety and object free areas available beyond runway end.
2. Displaced threshold established due to obstruction in approach area.
3. All markings must comply with the standards specified in AC 150/5340-1.
FIGURE 8-11
Runway edge and threshold lighting for a displaced threshold (Federal Aviation Administration).
307
308
Airport Design
RUNWAY LENGTH
1,000 FEET
BIDIRECTIONAL WHITE/RED
+12.5
75 FEET
–25
2,000 FEET
BIDIRECTIONAL
ALTERNATE
RED/WHITE AND WHITE
BIDIRECTIONAL WHITE
RUNWAY
END
CL
SEE NOTE 1
SEE NOTE 1
2,000 FEET
1,000 FEET
+12.5
75 FEET –25
CL
SEE NOTE 1
NOTE:
1. REFER TO PARAGRAPH 3.3a1 FOR RUNWAY CENTERLINE LIGHT FIXTURES PLACEMENT AND TOLERANCES.
LEGEND:
BIDIRECTIONAL RCL – WHITE BOTH DIRECTIONS
BIDIRECTIONAL RCL – RED IN DIRECTION OF SHADED SIDE
WHITE IN DIRECTION OF WHITE SIDE
FIGURE 8-12
Runway centerline lighting (Federal Aviation Administration).
Runway touchdown zone lights are white, consist of a three-bulb
bar on either side of the runway centerline, and extend 3000 ft from
the runway threshold or one-half the runway length if the runway is
less than 6000 ft long. They are spaced at intervals of 100 ft, with the
first light bar 100 ft from the runway threshold, and are located 36 ft
on either side of the runway centerline, as shown in Fig. 8-13. The
centerline lights are spaced at intervals of 50 ft. They are normally
offset a maximum of 2 ft from the centerline to avoid the centerline
paint line and the nose gear of the aircraft riding over the light fixtures. These lights are also white, except for the last 3000 ft of runway
Airport Lighting, Marking, and Signage
72' ± 1'
36' ± 6''
36' ± 6''
5' ± 1''
4
5' ± 1''
4
10' ± 1''
2
5' ± 1''
4
5' ± 1''
4
10' ± 1''
2
A
A
RUNWAY CL
2,900'
3D LIGHT BARS
EQUALLY SPACED ©
100' ± 2' INTERVALS
DETAIL A
MEASURE FROM
THIS EDGE
SEE DETAIL A
1/16''
DIRECTION OF
INSTRUMENT
APPROACH
MEASUREMENT IS FROM OUTSIDE
EDGE OF MIXTURE TO TOP OF
PAVEMENT AT EDGE OF MIXTURE
VIEW A
FIGURE 8-13
–A
100' ± 25'
Runway threshold lighting.
in the direction of aircraft operations, where they are color coded. The
last 1000 ft of centerline lights are red, and the next 2000 ft are alternated red and white.
Runway End Identifier Lights
Runway end identifier lights (REIL) are installed at airports where there
are no approach lights to provide pilots with positive visual identification
309
310
Airport Design
NOTES:
G
AIMIN
40°
90°
40° (+35, –0)
2. A 90 FT UPWIND AND A 40 FT DOWNWIND
LONGITUDINAL TOLERANCE IS PERMITTED FROM THE
RUNWAY THRESHOLD IN LOCATING THE LIGHT UNITS.
4. THE BEAM CENTERLINE (AIMING ANGLE) OF EACH
LIGHT UNIT IS AIMED 15 DEGREES OUTWARD FROM A
LINE PARALLEL TO THE RUNWAY CENTERLINE AND
INCLINED AT AN ANGLE 10 DEGREES ABOVE THE
HORIZONTAL, IF ANGLE ADJUSTMENTS ARE
NECESSARY, PROVIDE AN OPTICAL BAFFLE AND
CHANGE THE ANGLES TO 10 DEGREES HORIZONTAL
AND 20 DEGREES VERTICAL.
40°
THRESHOLD LIGHTS (REF)
AIMIN
5. LOCATE THE ADL EQUIPMENT A MINIMUM
DISTANCE OF 40 FT FROM OTHER RUNWAYS AND
TAXIWAYS.
G AN
15°
40° (+35, –0)
TAXIWAY
OR
RUNWAY
1. THE OPTIMUM LOCATION FOR EACH LIGHT UNIT
IS IN LINE WITH THE RUNWAY THRESHOLD AT 40 FT
FROM THE RUNWAY EDGE.
3. THE LIGHT UNITS SHALL BE EQUALLY SPACED
FROM THE RUNWAY CENTERLINE. WHEN
ADJUSTMENTS ARE NECESSARY THE DIFFERENCE IN
THE DISTANCE OF THE UNITS FROM THE RUNWAY
CENTERLINE SHALL NOT EXCEED 10 FT.
RUNWAY THRESHOLD
RUNWAY
CENTERLINE
LE
ANG
15°
PARALLEL TO
RUNWAY CENTERLINE
GL E
6. IF REILS ARE USED WITH PAPI. INSTALL REILS
AT 75 FT FROM THE RUNWAY EDGE. WHEN
INSTALLED WITH OTHER FACILITIES REILS SHALL
BE INSTALLED AT 40 FT FROM THE RUNWAY EDGE.
7. THE ELEVATION OF BOTH UNITS SHALL BE
WITHIN 3 FT OF THE HORIZONTAL PLANE THROUGH
THE RUNWAY CENTERLINE.
FIGURE 8-14 Typical layout for runway end identifier lights (REILs) (Federal Aviation
Administration).
of the approach end of the runway. The system consists of a pair of synchronized white flashing lights located on each side of the runway threshold
and is intended for use when there is adequate visibility. An illustration
and design specifications of REILs may be found in Fig. 8-14.
Taxiway Lighting
Either after a landing or on the way to takeoff, pilots must maneuver the
aircraft on the ground on a system of taxiways to and from the terminal
and hangar areas. Taxiway lighting systems are provided for taxiing at
night and also during the day when visibility is very poor, particularly at
commercial service airports.
The following overall guidance should be applied in determining
the lighting, marking, and signing visual aid requirements for taxiways:
• In order to avoid confusion with runways, taxiways must be
clearly identified.
• Runway exits need to be readily identified. This is particularly
true for high-speed runway exits so that pilots can be able to
locate these exits 1200 to 1500 ft before the turnoff point.
• Adequate visual guidance along the taxiway must be provided.
• Specific taxiways must be readily identified.
Airport Lighting, Marking, and Signage
• The intersections between taxiways, the intersections between
runways and taxiways, and runway-taxiway crossings need
to be clearly marked.
• The complete taxiway route from the runway to the apron
and from the apron to the runway should be easily identified.
There are two primary types of lights used for the designation of
taxiways. One type delineates the edges of taxiways [21] and the
other type delineates the centerline of the taxiway [27]. In addition,
there is an increasing use of lighting systems on taxiways, such as
runway guard lights (RGLs) and stop bars, to identify intersections
with runways, in an effort to reduce accidental incursions on to active
runway environments.
Taxiway Edge Lights
Taxiway edge lights are elevated blue colored bidirectional lights usually located at intervals of not more than 200 ft on either side of the
taxiway. The exact spacing is influenced by the physical layout of the
taxiways. Straight sections of taxiways generally require edge light
spacing in 200-ft intervals, or at least three lights equally spaced for
taxiway straight line sections less than 200 ft in length.
Closer spacing is required on curves. Light fixtures are located not
more than 10 ft from the edge of full strength pavement surfaces. The
lights cannot extent more than 30 inches above the pavement surface.
The spacing of lights along a curve is shown in Fig. 8-15. Entrance points
to runways and exit points from are lighted as shown in Fig. 8-16.
SIDES OF
TAXIWAY
PT
B
RADIUS “R”
OF CURVE
IN FEET
15
25
50
75
100
150
200
250
B
“Z”
B
“Z”
B
DIMENSION “Z”
IN FEET
20
27
35
40
50
55
60
70
RADIUS “R”
OF CURVE DIMENSION “Z”
IN FEET
IN FEET
300
80
400
95
500
110
600
130
700
145
800
165
900
185
1000
200 MAX.
PT
“R”
“R”
NOTES:
1. For radii not listed, determine “Z” spacing by linear interpolation.
2. “Z” is the arc length.
3. Uniformly space lights on curved edges. Do not exceed the
values determined from the above table.
4. On curved edges in excess of 30 degrees arc, do not install
less than three lights including those at the points of tangency (PT).
FIGURE 8-15
Typical taxiway lighting on curved sections.
311
312
W
W
RUNWAY
PT
PT
W
B
W
B
PT
2
30'
50'
3
300'
100'
100'
50'
200'
B
IW
AY
100'
TA
X
100'
1
100'
PT
100'
50'
200'
100'
50'
2
PT
PT
3
100' 800'
100'
PT
100'
PT
50'
100'
B
FIGURE 8-16
50'
NOTES
1. Taxiway edge light spacing on long straight taxiway sections
must not exceed 200 feet.
2. Taxiway Light spacing on curved sections must be as shown
on figure 17.
3. Taxiway edge light spacing on short sections is shown on
figures 10, 11, and 16.
4. Taxiway edge lights are blue. Runway edge lights are white
or yellow as specified in paragraph 2.1.2(a) of this AC.
Taxiway edge lighting configurations on straight line sections, curves, and runway intersection.
Airport Lighting, Marking, and Signage
Maximum Longitudinal Spacing
1200 ft (365 m)
RVR and Above
Below 1200 ft
(365 m) RVR
75 ft (23 m) to 399 ft (121 m)
25 ft (7.6 m)
400 ft (122 m) to 1199 ft (364 m)
≥1200 ft (365 m)
50 ft (15 m)
100 ft (30 m)
12.5 ft (4 m)
25 ft (7.6 m)
25 ft (7.6 m)
50 ft (15 m)
Acute-angled exits
50 ft (15 m)
50 ft (15 m)
Straight segments
100 ft (30 m)
50 ft (15 m)
Radius of curved centerlines
TABLE 8-1
Taxiway Centerline Lighting Spacing
Taxiway centerline lights are in-pavement bidirectional lights placed
in equal intervals over taxiway centerline markings. Taxiway centerline
lights are green, except in areas where the taxiway intersects with a
runway, where the green and yellow lights are placed alternatively.
Research and experience have demonstrated that guidance from
centerline lights is superior to that from edge lights, particularly in
low visibility conditions. The spacing of the lights on curves and tangents
is given in Table 8-1 [21].
For normal exits, the centerline lights are terminated at the edge of
the runway. At taxiway intersections the lights continue across the intersection. For long-radius high-speed exit taxiways, the taxiway lights are
extended onto the runway from a point 200 ft back from the point of
curvature (PC) of the taxiway to the point of tangency of the central curve
of the taxiway. Within these limits the spacing of lights is 50 ft. These
lights are offset 2 ft from the runway centerline lights and are gradually
brought into alignment with the centerline of the taxiway.
Where the taxiways intersect with runways and aircraft are required
to hold short of the runway, several yellow lights spaced at 5-ft intervals are placed transversely across the taxiway.
Runway Guard Lights
Runway guard lights (RGLs) are in-pavement lights located on taxiways at intersections of runways to alert pilots and operators of airfield
ground vehicles that they are about to enter onto an active runway.
RGLs are located across the width of the taxiway, approximately 2 ft
from the entrance to a runway, spaced at approximately 10-ft intervals,
as illustrated in Fig. 8-17. RGLs are unidirectional, colored yellow for
aircraft facing the runway.
313
314
Airport Design
2 FT. MAX
(610 mm MAX)
TAXIWAY CENTERLINE
LIGHT
2 FT. ± 2 IN.
(610 mm ± 50 mm)
9 FT.
10 IN. ± 2 IN.
(3 m ± 50 mm)
IN-PAVEMENT
RGL FIXTURE
FIGURE 8-17 Runway guard lights.
Runway Stop Bar
Similar to runway guard lights, runway stop bar lights are in-pavement
lights on taxiways at intersections with runways. As opposed to RGLs
that provide warning to pilots approaching a runway, runway stop bar
lights are designed to act as “stop” lights, directing aircraft and vehicles
on the taxiway not to enter the runway environment. Runway stop bar
lights are activated with red illuminations during periods of runway
occupancy or other instances where entrance from the taxiway to the
runway is prohibited. In-pavement runway stop bar lighting is typically installed in conjunction with elevated runway guard lights located
outside the width of the pavement. An illustration of a typical runway
stop bar lighting system is depicted in Fig. 8-18.
B
10 FT (3 M) MIN.
B
17 FT (5 M) MAX.
3 FT. 5 IN.
(1 M) MIN.
Y
10 FT.
(3 M) MAX.
2 FT. ± 2 IN.
(610 mm ± 50 mm)
R
R UNI
R UNI
9 FT. 10 IN. ± 2 IN.
(3 m ± 50 mm)
N.T.S.
NOTES
LEGEND
R UNI
IN-PAVEMENT STOP BAR FIXTURE
R
ELEVATED STOP BAR FIXTURE
B
TAXIWAY EDGE LIGHT
Y
R
B
B
ELEVATED RUNWAY GUARD LIGHT
FIGURE 8-18
Runway stop bar lighting.
1. THE ELEVATED RUNWAY GUARD LIGHT
AND ELEVATED STOP BAR MAY BE MOVED
UP TO 10 FEET (3 M) MAX. AWAY FROM
THE RUNWAY TO AVOID UNDESIRABLE
SPOTS.
2. WHERE SNOW REMOVAL OPERATIONS
OCCUR. IT IS ADVANTAGEOUS TO INSTALL
ELEVATED STOP BAR LIGHTS NOT CLOSER
TO THE TAXIWAY EDGE THAN THE LINE OF
TAXIWAY EDGE LIGHTS.
Y
Airport Lighting, Marking, and Signage
Runway and Taxiway Marking
In order to aid pilots in guiding the aircraft on runways and taxiways,
pavements are marked with lines and numbers. These markings are of
benefit primarily during the day and dusk. At night, lights are used to
guide pilots in landing and maneuvering at the airport. White is used
for all markings on runways and yellow is used on taxiways and
aprons. The FAA has developed a comprehensive plan for marking
runways and taxiways and they can be found in the FAA Advisory
Circular AC 150/5340-1J [17]. Similarly the ICAO recommendations
for marking are contained in Annex 14 [2].
Runways
The FAA has grouped runways for marking purposes into three
classes: (1) visual, or “basic” runways, (2) nonprecision instrument
runways, and (3) precision instrument runways. The visual runway
is a runway with no straight-in instrument approach procedure and
is intended solely for the operation of aircraft using visual approach
procedures. The nonprecision instrument runway is one having an
existing instrument approach procedure utilizing air navigation
facilities with only horizontal guidance (typically VOR or GPS-based
RNAV approaches without vertical guidance) for which a straight-in
nonprecision approach procedure has been approved. A precision
instrument runway is one having an existing instrument approach
procedure utilizing a precision instrument landing system or
approved GPS-based RNAV (area navigation) or RNP (required
navigation performance) precision approach. Runways that have a
published approach based solely on GPS-based technologies are
known as GPS runways.
Runway markings include runway designators, centerlines, threshold markings, aiming points, touchdown zone markings, and side
stripes. Depending on the length and class of runway and the type of
aircraft operations intended for use on the runway, all or some of the
above markings are required. Table 8-2 provides the marking requirements for visual, nonprecision, and precision runways.
Figure 8-19 illustrates the required marking for precision runways. Figure 8-20 illustrates the required markings for nonprecision
and visual runways (source: FAA AC 150/5340-1J).
Runway Designators
The end of each runway is marked with a number, known as a runway
designator, which indicates the approximate magnetic azimuth (clockwise from magnetic north) of the runway in the direction of operations.
The marking is given to the nearest 10° with the last digit omitted.
Thus a runway in the direction of an azimuth of 163° would be marked
as runway 16 and this runway would be in the approximate direction
of south-south-east. Therefore, the east end of an east-west runway
315
316
Airport Design
Marking Element
Visual
Runway
Nonprecision
Runway/GPS
Nonprecision
Precision
Runway/GPS
Precision
Designation
X
X
X
Centerline
X
X
X
Threshold marking
X∗
X
X
X
†
†
X
X
‡
Aiming point
X
Touchdown zone
Side stripes
X
‡
X
X
∗
Only required on runways used, or intended to be used, by international commercial
transport.
†
On runways 4000 ft (1200 m) or longer used by jet aircraft.
‡
Used when the full pavement width may not be available as a runway.
TABLE 8-2
Required Runway Markings
would be marked 27 (for 270° azimuth) and the west end of an east-west
runway would be marked 9 (for a 90° azimuth). If there are two parallel runways in the east-west direction, for example, these runways
would be given the designation 9L-27R and 9R-27L to indicate the
direction of each runway and their position (L for left and R for right)
relative to each other in the direction of aircraft operations. If a third
parallel runway existed in this situation it has traditionally been given
the designation 9C-27C to indicate its direction and position relative
(C for center) to the other runways in the direction of aircraft operations.
When there are four parallel runways, one pair is marked with the magnetic azimuth to the nearest 10° while the other pair is marked with the
magnetic azimuth to the next nearest 10°. Therefore, if there were four
parallel runways in the east-west direction, one pair would be designated as 9L-27R and 9R-27L and the other pair could be designated as
either 10L-28R and 10R-28L or 8L-26R and 8R-26L. This type of designation policy is increasingly being applied to three parallel runway
configurations, as well. For example, one pair would be designated as
9L-27R and 9R-27L and the third runway may be designated 10-28.
Runway designation markings are white, have a height of 60 ft
and a width, depending upon the number or letter used, varying from
5 ft for the numeral 1 to 23 ft for the numeral 7. When more than one
number or letter is required to designate the runway the spacing
between the designators is normally 15 ft. The sizes of the runway
designator markings are proportionally reduced only when necessary
due to space limitations on narrow runways and these designation
markings should be no closer than 2 ft from the edge of the runway or
the runway edge stripes. Specifications for individual runway designators are illustrated in Fig. 8-21.
THRESHOLD
20
6
RUNWAY DESIGNATION MARKING
150
45
40
12
=
3
SPACES
1
20
L
16
4.8
130
39
60
18
57
17
–
–
12
4 STRIPES
THRESHOLD MARKINGS
CONFIGURATION ‘A’
ACCEPTABLE UNTIL
YEAR 2008 ONLY
1000
300
STRIPES AND
SPACES EACH
5.75' (1.75 m)
WIDE
20
6
60
18
20
6
VARIES WITH
RUNWAY WIDTH
SEE Par. 10.d.
150
45
AIMING POINT
MARKING
40
12
120
36
75
22.5
CENTERLINE
3 WIDE
1
144
43.2
3
SIDE STRIPES
WIDE
1
500
150
6
STRIPES
2
72
21.6
30
10
5
SPACES
1.5
TOUCHDOWN ZONE
MARKINGS
500
150
72
21.6
500
150
TOUCHDOWN ZONE MARKINGS
150
45
11.5
3.5
THRESHOLD MARKINGS
CONFIGURATION ‘B’
NUMBER OF STRIPES
RELATED TO RUNWAY
WIDTH - SEE
Par. 9.d.(2)
FIGURE 8-19 Precision runway markings.
75
22.5
75
22.5
75
22.5
75
22.5
80
24
500
150
500
150
NOTE: DIMENSIONS EXPRESSED AS
FEET e.g., 10
METERS
3
500
150
317
318
20
6
1000
300
150
45
40
12
40
12
60
18
120
36
120
36
150
45
CENTERLINE MARKING
1.5
WIDE
0.5
20
THRESHOLD
80
24
72
21.6
30
10
RUNWAY DESIGNATION
PAVEMENT EDGE
THRESHOLD MARKINGS
MARKING
SEE FIGURE 1 FOR
ALTERNATE
CONFIGURATION
NONPRECISION RUNWAY MARKINGS
AIMING POINT
MARKING
(SEE NOTE 2)
VARIES WITH
RUNWAY WIDTH
(SEE NOTE 2)
NOTES: 1. DIMENSIONS EXPRESSED
e.g., 10
AS FEET
METERS
3
2. SEE Par. 10.d. FOR RUNWAY WIDTHS
OTHER THAN 150' (45 m) AND
REQUIREMENTS FOR AIMING
POINT MARKING
1000
300
20
6
60
18
40
12
120
36
120
36
80
24
80
24
120
36
20
CENTERLINE MARKING
1
WIDE
0.3
30
10
RUNWAY DESIGNATION MARKING
THRESHOLD
PAVEMENT EDGE
VISUAL RUNWAY MARKINGS
FIGURE 8-20
Nonprecision and visual runway markings.
AIMING POINT
MARKING
(SEE NOTE 2)
150
45
72
21.6
VARIES WITH
RUNWAY WIDTH
(SEE NOTE 2)
20
6
19
5.7
50
15
7
2.1
11
3.3
10
3
63
18.9
10
3
20
6
10
3
14
4.2
10
3
23
6.9
40
12
40
12
50
15
14
4.2
10
3
20
6
5
20 1.5
6
10
3
5
1.5
25
7.5
37
11.1
45˚
2
0.6
10
3
10
3
20
5
20
70
10
3
10
3
13
3.9
13
3.9
10
3
17
5.1
20
6
10
3
40
12
17
5.1
10
3
63
18.9
13
3.9
27
8.1
5
1.5
2
6
10
3
20
6
5
1.5
13
3.9
5
1.5
10
3
10 8 10
3 2.4 3
5 5
1.51.5
22
6.6
19
5.7
10
3
15
4.5
10
3
10
3
20
6
10
3
10
20
6
5
1.5
15
4.5
5
1.5
13
3.9
2.7
19
5.7
9
10 7
3 2.1
5
1.5
10
3
3
24
7.2
60
18
0.9
18
5.4
7 7 7 10
2.1 2.1 2.1 3
6 10
1.8 3
10
3
3
2
0.6
20
6
20
6
(SEE NOTE 4)
NOTES:
1. ALL NUMERALS EXCEPT THE NUMBER ELEVEN AS SHOWN ARE HORIZONTALLY SPACED 15 FEET (4.5 METERS) APART.
2. SINGLE DIGITS SHALL NOT BE PRECEDED BY A ZERO.
FEET e.g., 30
3. DIMENSIONS ARE EXPRESSED THUS:
METERS
9
4. THE NUMERAL 1, WHEN USED ALONE, CONTAINS A HORIZONTAL BAR TO DIFFERENTIATE IT FROM THE RUNWAY CENTERLINE MARKING.
5. SINGLE DESIGNATIONS ARE CENTERED ON THE RUNWAY PAVEMENT CENTERLINE. FOR DOUBLE DESIGNATIONS, THE CENTER OF THE
OUTER EDGES OF THE TWO NUMERALS IS CENTERED ON THE RUNWAY PAVEMENT CENTERLINE.
6. WHERE THE RUNWAY DESIGNATION CONSISTS OF A NUMBER AND A LETTER, THE NUMBER AND LETTER ARE LOCATED ON THE
RUNWAY CENTERLINE IN A STACKED ARRANGEMENT AS SHOWN IN FIGURE 1.
FIGURE 8-21
Runway designators.
319
320
Airport Design
Runway Width
Number of Stripes
60 ft (18 m)
4
75 ft (23 m)
6
100 ft (30 m)
8
150 ft (45 m)
12
200 ft (60 m)
16
TABLE 8-3
Striping Requirements for Runway
Threshold Markings
Runway Threshold Markings
Runway threshold markings identify to the pilot the beginning of the
runway that is safe and available for landing. Runway threshold markings begin 20 ft from the runway threshold itself.
Runway threshold markings consist of two series of white stripes,
each stripe 150 ft in length and 5.75 ft in width, separated about the
centerline of the runway. On each side of the runway centerline, a number of threshold marking stripes are placed, in accordance with the width
of the runway, as specified in Table 8-3. Table 8-3 specifies the total
number of runway threshold stripes required. For example, for a 100-ft
runway, eight stripes are required, in two groups of four are placed about
the centerline. Stripes within each set are separated by 5.75 ft. Each set of
stripes is separated by 11.5 ft about the runway centerline.
The above specifications for runway threshold markings were
adapted by the FAA from ICAO international standards and made
mandatory for United States civil use airports in 2008.
Centerline Markings
Runway centerline markings are white, located on the centerline of
the runway, and consist of a line of uniformly spaced stripes and gaps. The
stripes are 120 ft long and the gaps are 80 ft long. Adjustments to the
lengths of stripes and gaps, where necessary to accommodate runway
length, are made near the runway midpoint. The minimum width of
stripes is 12 in for visual runways, 18 in for nonprecision instrument
runways, and 36 in for precision instrument runways. The purpose of
the runway centerline markings is to indicate to the pilot the center of the
runway and to provide alignment guidance on landing and takeoff.
Aiming Points
Aiming points are placed on runways of at least 4000 ft in length to
provide enhanced visual guidance for landing aircraft. Aiming point
markings consist of two bold stripes, 150 ft long, 30 ft wide, spaced
Airport Lighting, Marking, and Signage
Runway Length
Markings on Each End
7990 ft (2436 m) or greater
Full set of markings
6990 ft (2130 m) to 7989 ft (2435 m)
Less one pair of markings
5990 ft (1826 m) to 6989 ft (2129 m)
Less two pairs of markings
4990 ft (1521 m) to 5989 ft (1825 m)
Less three pairs of markings
TABLE 8-4
Touchdown Zone Marking Requirements
72 ft apart symmetrically about the runway centerline, and beginning
1020 ft from the threshold.
Touchdown Zone Markings
Runway touchdown zone markings are white and consist of groups
of one, two, and three rectangular bars symmetrically arranged in
pairs about the runway centerline. These markings begin 500 ft from
the runway threshold. The bars are 75 ft long, 6 ft wide, with 5 ft
spaces between the bars, and are longitudinally spaced at distances
of 500 ft along the runway. The inner stripes are placed 36 ft on either
side of the runway centerline. For runways less than 150 ft in width,
the width and spacing of stripes may be proportionally reduced.
Where touchdown zone markings are installed on both runway ends
on shorter runways, those pairs of markings which would extend to
within 900 ft of the runway midpoint are eliminated. In addition, sets
of touchdown zone markings are eliminated for shorter runways, as
specified in Table 8-4.
Side Stripes
Runway side stripes consist of continuous white lines along each side
of the runway to provide contrast with the surrounding terrain or to
delineate the edges of the full strength pavement. The maximum distance between the outer edges of these markings is 200 ft and these
markings have a minimum width of 3 ft for precision instrument runways and are at least as wide as the width of the centerline stripes on
other runways.
Displaced Threshold Markings
At some airports it is desirable or necessary to “displace” the runway
threshold on a permanent basis. A displaced threshold is one which
has been moved a certain distance from the end of the runway. Most
often this is necessary to clear obstructions in the flight path on landing. The displacement reduces the length of the runway available for
landings, but takeoffs can use the entire length of the runway. The FAA
321
322
Airport Design
NOTES
1. RUNWAY SIDE STRIPES, WHEN USED ON THE RUNWAY,
EXTEND INTO THE DISPLACED AREA.
2. RUNWAY MARKINGS (EXCEPT HOLDING POSITION
MARKINGS), INCLUDING THOSE IN THE DISPLACED
THRESHOLD AREA, ARE WHITE.
FEET
10
e.g.,
3. DIMENSIONS EXPRESSED AS
METERS
3
RUNWAY SIDE
STRIPES (WHITE)
TAXIWAY
CENTERLINE
MARKINGS
(YELLOW)
1.5
5
5
1.5
TAIL
15
4.5
20
24
>
SEE FIGURE 11, DETAIL ‘A’
80
24
>
>
> >
>
>
RUNWAY THRESHOLD IS AT
OUTBOARD EDGE OF
THRESHOLD BAR
45
13.5
3
1
5
1.5
SEE DETAIL ‘A’
AND TABLE BELOW
W- RUNWAY WIDTH
HEAD
DETAIL ‘A’ (ARROW)
RUNWAY
WIDTH
TAXIWAY
EDGE
STRIPES
(YELLOW)
STANDARD RUNWAY
MARKING
20
6
SEE DETAIL ‘A’ FOR
ARROW DIMENSIONS
200
60
100
30
120
36
10
3
THRESHOLD
BAR (WHITE)
# OF ARROW
HEADS
SPACING BETWEEN
ARROW HEADS
SPACING TO
RUNWAY EDGE
≥ 100' (30 M)
4
W/4
W/8
< 100' (30 M)
3
W/3
W/6
< 60' (30 M)
2
W/2
W/4
NOTE: ‘W’ IS THE RUNWAY WIDTH
FIGURE 8-22
Displaced threshold markings.
requires that displaced thresholds be marked as shown in Fig. 8-22.
These markings consist of arrows and arrow heads to identify the displaced threshold and a threshold bar to identify the beginning of the
runway threshold itself. Displaced threshold arrows are 120 ft in
length, separated longitudinally by 80 ft for the length of the displaced
threshold. Arrow heads are 45 ft in length, placed 5 ft from the threshold bar. The threshold bar is 5 ft in width and extends the width of the
runway at the threshold.
Blast Pad Markings
In order to prevent erosion of the soil, many airports provide a paved
blast pad 150 to 200 ft in length adjacent to the runway end. Similarly,
some airport runways have a stopway which is only designed to support
aircraft during rare aborted takeoffs or landing overruns and is not
designed as a full strength pavement. Since these paved areas are not
designed to support aircraft and yet may have the appearance of being
so designed, markings are required to indicate this. The markings for
blast pads and stopways are shown in Fig. 8-23. Likewise the area adjacent to the edge of the runway may have a paved shoulder not capable
Airport Lighting, Marking, and Signage
3
0.9 MINIMUM
PAVEMENT
EDGE
RUNWAY THRESHOLD IS
AT OUT BOARD EDGE OF
THRESHOLD BAR
STANDARD
RUNWAY
MARKINGS
5
1.5
MAX.
5
MAX.
1.5
100
30
100 50 50
30 15 15
NOTES:
1. 50 FOOT (15 m) SPACING MAY BE USED WHEN LENGTH OF AREA IS
LESS THAN 250 FEET (75 m) IN WHICH CASE THE FIRST FULL CHEVRON
STARTS AT THE INDEX POINT (INTERSECTION OF RUNWAY CENTERLINE AND
RUNWAY THRESHOLD).
2. CHEVRONS ARE YELLOW AND AT AN ANGLE OF 45 DEGREES TO THE
RUNWAY CENTERLINE.
3. CHEVRON SPACING MAY BE DOUBLED IF LENGTH OF AREA EXCEEDS
1000 FEET (300 m).
FEET
e.g., 10
4. DIMENSIONS ARE EXPRESSED AS
METERS
3
FIGURE 8-23
Blast pad markings.
of supporting aircraft. These areas are marked with a 3-ft-wide stripe, as
shown in Fig. 8-24. Yellow color is used for these types of markings.
Taxiway Markings
Taxiway markings consist of centerline markings, holding position
markings, and often edge markings. Taxiways are marked as shown in
Fig. 8-25.
Centerline and Edge Markings
The centerline of the taxiway is marked with a single continuous 6-in
yellow line. On taxiway curves, the taxiway centerline marking continues from the straight portion of the taxiway at a constant distance
from the outside edge of the curve. At taxiway intersections which
are designed for aircraft to travel straight through the intersection,
the centerline markings continue straight through the intersection. At
the intersection of a taxiway with a runway end, the centerline stripe
of the taxiway terminates at the edge of the runway.
At the intersection between a taxiway and a runway, where the
taxiway serves as an exit from the runway, the taxiway marking is usually
323
Airport Design
45°
100
30
MIDPOINT OF
RUNWAY
30
3
0.9
100
45°
45°
5
MAX.
1.5
30
30
45°
100
5
MAX.
1.5
15
100
5
MAX.
1.5
50
324
RUNWAY THRESHOLD
DIMENSIONS ARE
EXPRESSED THUS:
FEET e.g., 10
METERS
3
FIGURE 8-24
Runway shoulder markings.
extended on to the runway in the vicinity of the runway centerline
marking. The taxiway centerline marking is extended parallel to the
runway centerline marking a distance of 200 ft beyond the point of
tangency. The taxiway curve radius should be large enough to provide a clearance to the taxiway edge and the runway edge of at least
one-half the width of the taxiway. For a taxiway crossing a runway,
the taxiway centerline marking may continue across the runway but
it must be interrupted for the runway markings.
When the edge of the full strength pavement of the taxiway is
not readily apparent, or when a taxiway must be outlined when it is
325
15
Airport Lighting, Marking, and Signage
SEE
TABLE 4
SEE
TABLE 4
SEE DETAIL ‘A’
TAXIWAY/RUNWAY
HOLDING POSITION
MARKINGS*
ILS HOLDING POSITION
MARKINGS*
REQUIRED DISTANCE
FROM RUNWAY
CENTERLINE
NOTE THAT HOLDLINE
WOULD INFRINGE ON
PARALLEL TAXIWAY IF
NOT REORIENTED
3' (1 m)
DETAIL ‘A’
3’ DIMENSION IS
EDGE TO EDGE
TAXIWAY EDGE
MARKINGS,
DASHED*
TAXIWAY EDGE
MARKINGS,
CONTINUOUS*
INTERMEDIATE HOLDING
POSITION MARKINGS*
EXAMPLE OF HOLDING POSITION MARKINGS NOT AT
RIGHT ANGLE TO TAXIWAY CENTERLINE BECAUSE OF
INTERSECTION CONFIGURATION
HOLDING BAY
*REFER TO FIGURE TO
FOR MARKING DETAILS
RUNWAY
RUNWAY
SEE AC 150/5340–18
FOR SIGN REQUIREMENTS
AT HOLDING POSITION MARKINGS
TAXIWAY
EXAMPLE WHERE HOLDING POSITION MARKINGS
DO NOT EXTEND STRAIGHT ACROSS THE TAXIWAY
HOLDING
BAY
POFZ MARKINGS
TAXIWAY
EXAMPLE OF HOLDING POSITION MARKINGS
EXTENDED ACROSS HOLDING BAY
NOTE: FOR CAT II & III APPROACHES
MAINTAIN A CLEAR SECTION
200‘x1000’ AT RUNWAY END.
FIGURE 8-25
Taxiway markings.
established on a large paved area such as an apron, the edge of the
taxiway is marked with two continuous 6-in wide yellow stripes
that are 6 in apart.
Taxiway Hold Markings
For taxiway intersections where there is an operational need to hold
aircraft, a dashed yellow holding line is placed perpendicular to and
across the centerline of both taxiways.
When a taxiway intersects a runway or a taxiway enters an instrument landing system critical area, a holding line is placed across the
taxiway. The holding line for a taxiway intersecting a runway consists of two solid lines of yellow stripes and two broken lines of
yellow stripes placed perpendicular to the centerline of the taxiway
and across the width of the taxiway. The solid lines are always placed
on the side where the aircraft is to hold. The holding line for an instrument landing system critical area consists of two solid lines placed
326
Airport Design
Visual and
Nonprecision
Instrument, ft (m)
Precision
Instrument, ft (m)
A and B (I and II) small
airplanes only
125 (38)
175 (53)
A and B (I, II, and III)
200 (60)
250 (75)
A and B (IV)
250 (75)
250 (75)
C and D (I through IV)
250 (75)
250 (75)
C and D (V)
250 (75)
280 (85)
C and D (VI)
250 (75)
280 (85)
Aircraft Approach Category
and (Airplane Design Group)
Source: AC 150/5340-18D
Distances shown above are for planning purposes only. “Hold position markings” must be placed in order to restrict the largest aircraft (tail or body) expected
to use the runway from penetrating the obstacle-free zone.
For aircraft approach categories A and B, airplane design group III, this distance
is increased 1 ft for each 100 ft above 5100 ft above sea level. For airplane design
group IV, precision instrument runways, this distance is increased 1 ft for each
100 ft above sea level.
For aircraft approach category C, airport design group IV, precision instrument
runways. This distance is increased 1 ft for each 100 ft above sea level. For airplane
design group V, this distance is increased 1 ft for each 100 ft above sea level.
For aircraft approach category D, this distance is increased 1 ft for each 100 ft
above sea level.
TABLE 8-5
Location Distances for Holding Position Markings
perpendicular to the taxiway centerline and across the width of the
taxiway joined with three sets of two solid lines symmetrical about
and parallel to the taxiway centerline. These holding lines are located
the minimum distance from the centerline of the runway as indicated
in Table 8-5 and illustrated in Fig. 8-26.
Taxiway Shoulders
In some areas on the airfield, the edges of taxiways may not be welldefined due to their adjacency to other paved areas such as aprons
and holding bays. In these areas, it is prudent to mark the edges of
taxiways with shoulder markings. Taxiway shoulder markings are
yellow in color, and are often painted on top of a green background.
The shoulder markings consist of 3-ft-long yellow stripes placed perpendicular to the taxiway edge stripes, as illustrated in Fig. 8-27. On
straight sections of the taxiway, the marks are placed at a maximum
spacing of 100 ft. On curves, the marks are placed on a maximum of
50 ft apart between the curve tangents.
4 LINES (YELLOW) AND
3 SPACES AT 12" (30 cm) EACH
(MAY BE REDUCED
IN CERTAIN CIRCUMSTANCES
SEE PAR. 23D.)
DISTANCE TO RUNWAY
CENTERLINE MEASURED
FROM MARKING EDGE ON
AIRCRAFT HOLDING SIDE
12" (30 cm)
ALL MARKINGS
YELLOW AND
1' (0.3 m) WIDE
2' (0.6 m) WIDE
DASHES (YELLOW) AND
SPACES 3' (0.9 m)
IN LENGTH
3' (0.9 m)
ILS/MLS CRITICAL
AREA BOUNDARY
(MAY BE REDUCED
IN CERTAIN
CIRCUMSTANCES
SEE PAR. 24D.)
10'
3m
AIRCRAFT
HOLDING
SIDE
RUNWAY HOLDING
POSITION MARKINGS
TAXIWAY CENTERLINE
MARKING, YELLOW,
6" TO 12" (15 cm
TO 30 cm) WIDE
DASHES & SPACES
3" (0.9 m) IN LENGTH
1" (0.3 m) IN WIDTH
COLOR, YELLOW
6–12"
(15–30 cm)
6–12"
(15–30 cm)
AIRCRAFT
HOLDING
SIDE
INTERMEDIATE HOLDING
POSITION MARKINGS
FIGURE 8-26
Taxiway hold short and edge markings.
3' (0.9 m)
4'
1.3 m
8'
2.4 m
6–12"
(15–30 cm)
6–12"
(15–30 cm)
1'
0.3 m
AIRCRAFT
HOLDING
SIDE
TAXIWAY CENTERLINE
MARKING, YELLOW,
6" TO 12" (15 cm
TO 30 cm) WIDE
ILS/MLS HOLDING POSITION
MARKINGS
DOUBLE
YELLOW
LINES
6" (15 cm)
WIDTH W/
6" (15 cm)
BETWEEN
LINES
TAXIWAY EDGE
MARKINGS,
CONTINUOUS
(CAN BE USED TO
DESIGNATE ISLANDS)
4' (1.3 m)
4' (1.3 m)
12" (30 cm)
ROADWAY EDGE STRIPES
WHITE, ZIPPER, STYLE
DASHED LINE ON
MOVEMENT SIDE
15
4.5
3' (1 m)
25
7.5
3' (1 m)
15
4.5
3' (1 m)
TAXIWAY EDGE
MARKINGS,
DASHED
(CANNOT BE USED TO
DESIGNATE ISLANDS)
BOTH LINES
ARE YELLOW,
6" (15 cm)
IN WIDTH AND
6" (15 cm)
SPACE BETWEEN
LINES
SOLID LINE ON
SIDE
NON-MOVEMENT
NON-MOVEMENT
AREA MARKINGS
327
328
Airport Design
RUNWAY
PAVEMENT
EDGE
50' (15 m) MAX.
ON CURVES
INBOARD OR
OUTBOARD
100' (30 m)
MAX. ON
STRAIGHT
SECTIONS
YELLOW STRIPES
3' (1 m) WIDE
EXTEND TO WITHIN
5 FEET (1.5 m) OF
PAVEMENT EDGE OR
25 FEET (7.5 m)
IN LENGTH,
WHICHEVER IS LESS
TAXIWAY EDGE
MARKINGS
FIGURE 8-27
Taxiway shoulder markings.
Enhanced Taxiway Markings
Beginning in 2008, all airports serving commercial air carriers are
required to mark certain critical areas of the airfield with enhanced
taxiway markings. These markings are designed to provide additional guidance and warning to pilots of runway intersections.
Enhanced markings consist primarily of yellow-painted lines, using
paint mixtures with imbedded glass beads to enhance visibility. In
addition, yellow markings must be marked on top of a darkened
black background.
Taxiway centerlines are enhanced for 150 ft from the runway
hold-short markings. The centerline enhancements include dashed
yellow lines 9 ft in length, separated longitudinally by 3 ft. These
yellow lines are placed 6 in from each end of the existing centerline.
An example of enhanced marking is illustrated in Fig. 8-28.
Closed Runway and Taxiway Markings
When runways or taxiways are permanently or temporarily closed to aircraft, yellow crosses are placed on these trafficways. For permanently
Airport Lighting, Marking, and Signage
9'(2.74 m)
6–12''
(15–30 cm)
See Notes 1 and 2
3' (.91 m)
3'' (7.62 cm)
150' (45.72 m)
6'' (15.24 cm)
6'' (15.24 cm)
6' (1.83 m)
Note 1: Regardless of whether the
centerline is 6 inches or 12 inches
(15 or 30 cm) wide, the dashed lines
provided by the enhancements will
always be 6 inches (15 cm) in width.
Note 2: The taxiway centerline
might have to be shifted either right
or left so the enhancement does not
go over a taxiway centerline light.
FIGURE 8-28 Example of enhanced taxiway markings.
closed runways, the threshold, runway designation, and touchdown
markings are obliterated and crosses are placed at each end and at
1000 ft intervals. For temporarily closed runways, the runway markings are not obliterated, the crosses are usually of a temporary type
and are only placed at the runway ends. For permanently closed taxiways, a cross is placed on the closed taxiway at each entrance to the
taxiway. For temporarily closed taxiways barricades with orange and
white markings are normally erected at the entrances.
Airfield Signage
In addition to markings, signage is placed on the airfield to guide and
direct pilots and ground vehicle operators to points on the airport. In
addition some signage exists to provide the pilots with information
regarding their position on the airfield, the distance remaining on a
runway, the location of key facilities at the airport, and often informative signage ranging from voluntary procedures to mitigate noise
impacts to warnings about nearby security sensitive areas. FAA
Advisory Circular 150/53040-18D describes the U.S. federal standards
for airport sign systems.
329
330
Airport Design
FIGURE 8-29
Runway distance remaining sign.
Runway Distance Remaining Signs
Runway distance remaining signs are placed on the side of a runway
and provide the pilot with information on how much runway is left
during takeoff or landing operations. These signs are placed at 1000 ft
intervals along the runway is a descending sequential order. Normally, these signs consist of white numerals on a black background,
as illustrated in Fig. 8-29.
The FAA recommends that the signs be configured in one of three
ways [25]. The preferred method of configuration, and the most economical, is to place double-faced signs on only one side of the runway. In this configuration it is recommended that the signs be placed
on the left side of the most frequently used direction of the runway.
The signs may be placed on the right side of the runway when necessary due to required runway-taxiway separations or due to conflicts
between intersecting runways or taxiways. An alternative method is
to provide a set of single-faced signs on either side of the runway to
indicate the distance remaining when the runway is used in both
directions. The advantage of this configuration is that the distance
remaining is more accurately reflected when the runway length is not
an even multiple of 1000 ft. Another alternative uses double-faced
signs on both sides of the runway. The advantage of this method is
that the runway distance is displayed on both sides of the runway in
each direction which is an advantage when a sign on one side needs
to be omitted because of a clearance conflict. When the runway distance is not an even multiple of 1000 ft, one half of the excess distance
is added to the distance on each sign on each runway end. For example, if the runway length available is 8250 ft, the last sign is located at
Airport Lighting, Marking, and Signage
Sign
Size
Legend,
in (cm)
Face, in
(cm)
Installed
(max.), in
(cm)
Distance
from Defined
Pavement Edge
4
40 (100)
48 (120)
60 (152)
50–75 (15–22.5)
5
25 (64)
30 (76)
42 (107)
20–35 (6–10.5)
TABLE 8-6
Runway Distance Remaining Sign Heights and Location Distances
a distance of 1000 plus 125 ft from the end of the runway. A tolerance
of ±50 ft is allowed for the placement of runway distance remaining
signs. These signs should be illuminated anytime the runway edge
lights are illuminated. The recommended sizes and placement of
these signs is given in Table 8-6.
Taxiway Guidance Sign System
The primary purpose of a taxiway guidance sign system is to aid pilots
in taxiing on an airport. At controlled airports, the signs supplement
the instructions of the air traffic controllers and aid the pilot in complying with those instructions. The sign system also aids the air traffic controller by simplifying instructions for taxiing clearances, and
the routing and holding of aircraft. At locations not served by air
traffic control towers, or for aircraft without radio contact, the sign
system provides guidance to the pilot to major destinations areas in
the airport.
The efficient and safe movement of aircraft on the surface of an
airport requires that a well-designed, properly thought-out, and standardized taxiway guidance sign system is provided at the airport. The
system must provide the pilot with the ability to readily determine the
designation of any taxiway on which the aircraft is located, readily
identify routings to a desired destination on the airport property, indicate mandatory aircraft holding positions, and identify the boundaries
for aircraft approach areas, instrument landing system critical areas,
runway safety areas and obstacle free zones. It is virtually impossible,
except for holding position signs, to completely specify the locations
and types of signs that are required on a taxiway system at a particular
airport due to the wide variation in the types of functional layouts for
airports. The ICAO also publishes recommendations relative to surface
movement guidance and control systems [2, 15].
Taxiway Designations
Taxiway guidance sign systems are in a large part based on a system
of taxiway designators which identify the individual taxiway components. While runway designators are based on the magnetic heading of the runway, taxiway designators are assigned based on an
331
332
Airport Design
alphabetic ordering system, independent of the taxiways direction of
movement. Taxiways are typically identified in alphabetic order from
east to west or north to south (i.e., the northern or easternmost taxiway would be designated “A”, the next southern or western taxiway
would be designated “B,” and so forth). Entrance and exit taxiways
perpendicular to main parallel taxiways are designated by the letter of
the main parallel taxiway from which they spur, followed by a numeric
sequence. For instance, the northernmost entrance taxiway off of taxiway “A” would be designated “A1,” and so forth. The letters “I” and
“O” are not used as taxiway designators due to their similarity in form
to the numbers “1” and “0.” In addition the letter “X” is not used as a
taxiway designator due to its similarity to a closed runway marking.
An example taxiway designation scheme is illustrated in Fig. 8-30.
The taxiway guidance sign system consists of four basic types of
signs: mandatory instruction signs, which indicate that aircraft should
not proceed beyond a point without positive clearance, location signs,
which indicate the location of an aircraft on the taxiway or runway
system and the boundaries of critical airfield surfaces, direction signs,
which identify the paths available to aircraft at intersections, and destination signs, which indicate the direction to a particular destination.
25
N
15
IN THIS EXAMPLE, TAXIWAYS HAVE BEEN
DESIGNATED FROM NORTH TO SOUTH AND
THEN EAST TO WEST.
A
B*
B1
B2
B
* THESE TAXIWAYS COULD
ALSO BE DESIGNATED AS
B WITH A NUMERIC, E.G., B3
A
J
7
K*
** THESE TAXIWAYS COULD
ALSO BE DESIGNATED AS
D WITH A NUMERIC, E.G.,
D1, D2
B
A
B
A
J
H
J
D
D
C
H
C2
J
D
H
C
D
D
H
G**
F**
J
APRON
FIGURE 8-30
Example of taxiway designation scheme.
D
C1
C
33
6
27
K
E
C
E
D
D
Airport Lighting, Marking, and Signage
Types of Taxiway Signs
Mandatory Instruction Signs
Mandatory instruction signs denote an entrance to a runway, critical
area, or prohibited area. They are used for holding positions signs for
runway-taxiway and runway-runway intersections (Fig. 8-31a), instrument landing system critical areas (Fig. 8-31b), runway approach areas
(Fig. 8-31c), ILS category II/III critical areas (Fig. 8-31d), and to designate areas for which entry is prohibited by aircraft (Fig. 8-31e). These
signs have white inscriptions on a red background and are installed
on the left side of the runway or taxiway. In some cases runwaytaxiway intersections require a sign on both sides of the taxiway. This
includes situations on taxiways which are at least 150 ft wide, where
the painted holding line extends across an adjacent holding bay,
where the painted holding line markings do not extend straight
across the taxiway, and where the painted holding line markings are
located a short distance from an intersection with another taxiway.
Generally arrows are not permitted on mandatory instruction signs
unless they are necessary at the taxiway-runway-runway intersections
to indicate directions to these runways. For runway designation these
signs normally contain both designations of the runway and the designation on the left is for the runway to the left and the designation on
the right is for the runway to the right.
At controlled airports aircraft and ground vehicles are required to
hold at these points unless cleared by air traffic control. At uncontrolled
airports, these signs are intended to indicate travel beyond these signs
is permitted only after appropriate precautions have been taken.
(a) Runway intersection
(b) ILS critical area
(c) Runway approach area
(d) ILS CAT II/III critical area
(e) No entry
FIGURE 8-31 Mandatory instruction signs.
333
334
Airport Design
(a) Taxiway location sign
(c) Boundary sign
runway safety area/OFZ
runway approach area
(b) Runway location sign
(d) Boundary sign
ILS critical area
POFZ Boundary
ILS CAT II/III operations
FIGURE 8-32 Location signs.
Location Signs
Location signs are used to identify the taxiway or runway on which an
aircraft is located (Fig. 8-32a and 8-32b). These signs consist of a yellow
inscription and border on a black background. Location signs are also
used to identify the boundary of the runway safety area or obstaclefree zones (Fig. 8-32c), or the instrument landing system critical area
(Fig. 8-32d) for a pilot exiting a runway. In the latter cases the signs consist of a black inscription and border on a yellow background and the
inscription on the sign is the same as relevant holding line marking.
Direction Signs
Direction signs are used to indicate the direction of other taxiways
leading out of an intersection. These signs are used as taxiway direction
sign (Fig. 8-33) and runway exit sign. The signs have black inscriptions and borders on a yellow background and always contain arrows.
The arrows are oriented in the approximate direction of the turn
required. These signs should not be located with holding position
signs and should not be located between the holding line and the runway.
FIGURE 8-33 Taxiway direction sign.
Airport Lighting, Marking, and Signage
FIGURE 8-34 Inbound destination sign (to military facility).
Signs used to indicate the direction of taxiways on the opposite side of
the runway should be located on the opposite side of the runway. Runway exit signs should be located prior to the exit on the side of the
runway on which the aircraft is expected to exit. If the taxiway crosses
the runway and the aircraft could be expected to exit on either side, then
a runway exit sign should be installed on either side of the runway.
Destination Signs
Destination signs have black inscriptions on a yellow background
and always contain arrows. These signs indicate the general direction
to a remote location at the airport, such as an inbound destination
(Fig. 8-34), and are generally not required where taxiway direction
signs are used. Outbound destination signs are used to identify directions to the takeoff runways. These routes normally begin at the entrance
to a taxiway from the apron area. More than one runway number may
be used, separated by a dot, if the route is common to more than one
runway (Fig. 8-35). Inbound destination signs are often used to indicate the general direction to major airport facilities such as passenger
terminal aprons, cargo areas, military aprons, or general aviation facilities. These signs should consist of a minimum of three letters to avoid
confusion with taxiway guidance signs.
The typical legends found on taxiway destination signs are:
APRON—general parking, servicing, and loading areas
FUEL—areas where aircraft are fueled or serviced
TERM—gate positions at which aircraft are loaded or unloaded
CIVIL—areas set aside for civil aircraft
MIL—areas set aside for military aircraft
PAX—areas set aside for passenger handling
CARGO—areas set aside for cargo handling
INTL—areas set aside for handling international flights
FBO—fixed-base operator
FIGURE 8-35 Outbound destination sign (to runways 27 and 33).
335
336
Airport Design
FIGURE 8-36 Taxiway ending marker.
Information Signs
Other types of signs may be necessary on the airfield which are not
part of the taxiway guidance systems described before. These signs
are called information signs and might be used, for example, to indicate
a noise abatement procedure to a pilot ready to takeoff on a specific
runway. These signs should have black inscriptions on a yellow background. These signs are not required to be lighted.
Taxiway Ending Sign
The sign system does not provide a sign to indicate that a taxiway
does not continue beyond an intersection. A frangible, retroreflective
sign should be installed on the far side of the intersection if normal
visual cues such as marking and lighting are inadequate. This sign is
marked with alternating black and yellow diagonal stripes, as illustrated in Fig. 8-36.
The FAA recommends that the following guidelines be applied
when designing a taxiway guidance sign system [25]:
1. A holding position sign and taxiway location sign should be
installed at the holding position on any taxiway that provides
access to a runway.
2. A holding position sign should be installed on any taxiway at
the boundary of the instrument landing system critical area
or the runway approach area when it is necessary to protect
the navigational signal, airspace, or safety area for a runway.
This sign should be placed at the entrance to and the exit from
such areas.
3. A holding position sign should be installed on any runway
where that runway intersects another runway.
4. A sign array consisting of taxiway direction signs should be
installed prior to each intersection between taxiways if an aircraft would normally be expected to turn at or hold short of
the intersection. The direction sign in the array should include
a sign panel, consisting of a taxiway designation and an arrow,
for each taxiway that an aircraft would be expected to turn
onto or hold short. A taxiway location sign should be included
as part of the sign array unless it is determined to be unnecessary. If an aircraft normally would not be expected to turn at
Airport Lighting, Marking, and Signage
or hold short of the intersection, the sign array is not needed
unless the absence of guidance would cause confusion.
5. A runway exit sign identifying the exit taxiway should be
installed along each runway for each normally used runway
exit.
6. Destination signs may be substituted for direction signs at
the intersection between taxiways or for runway exit signs at
uncontrolled airports.
7. Standard highway stop signs should be installed on ground
vehicle roadways at the intersection of each roadway with a
runway or taxiway. For roadway intersections with taxiways,
a standard highway yield sign may be used instead of the
stop sign.
8. Additional signs should be installed on the airfield where
necessary to eliminate confusion or to provide confirmation
relative to location.
Signing Conventions
The FAA recommends the following signing conventions [25]:
1. Signs should be placed on the left side of the taxiway as viewed
by the pilot of an approaching aircraft. If signs are installed on
both sides of the taxiway at the same location, the sign faces
should be identical. Signs may be placed on the right side of
the taxiway when necessary to meet clearance requirements or
where it is impractical to install them on the left side because of
terrain features or conflicts with other objects.
2. Some signs may be installed on the back of other signs even
though this may result in the sign being on the right side of the
taxiway. Signs which may be installed in this manner include
a. Runway safety area, obstacle-free zone area, and runway
approach area boundary signs may be installed on the
back of taxiway-runway intersection and runway approach
area holding position signs.
b. Instrument landing system critical area boundary signs
may be installed on the back of instrument landing system
critical area holding position signs.
c. Taxiway location signs, when installed on the far side of the
intersection, may be installed on the back of direction signs.
d. Taxiway location signs may be installed on the back of
holding position signs.
e. Destination signs may be installed on the back of direction
signs on the far side of intersections when the destination
referred to is straight ahead.
337
338
Airport Design
3. Taxiway location signs installed in conjunction with holding
position signs for taxiway-runway intersections should always
be installed outboard of the holding position sign.
4. Location signs are normally included as part of a direction
sign array located prior to the taxiway intersection. Except for
the intersection of two taxiways, the location sign is placed in
the array so that the designations for all turns to the left would
be located to the left side of the location sign and designations
for all turns to the right or straight ahead are located to the right
of the location sign.
5. All direction signs have arrows. Arrows on signs should be
oriented toward the approximate direction of the turn. Each
designation appearing in the array of direction signs should
only have one arrow. An exception is when the taxiway intersection comprises only two taxiways and then the direction
sign for the taxiway may have two arrows.
6. Destination signs should be located in advance of intersections and should not be collocated with other signs. These
may also be installed on the far side of the intersection when
the taxiway does not continue and direction signs are provided
prior to the intersection.
7. Information signs should not be collocated with mandatory,
location, direction, or destination signs.
8. Each designation and its associated arrow included in the array
of direction signs or destination signs should be delineated from
the other designations in the array by a black vertical border.
Sign Size and Location
Taxiway guidance signs are available in three heights as indicated in
Table 8-7. The choice of a particular size sign involves several factors
including effectiveness, aircraft clearance, jet blast, and snow removal
Perpendicular Distance
from Defined Taxiway/
Runway Edge to Near
Side of Sign, ft (m)
Sign
Size
Legend,
in (cm)
Face,
in (cm)
Installed
(max.),
in (cm)
1
12 (30)
18 (46)
30 (76)
10–20 (3–6)
2
15 (38)
24 (61)
36 (91)
20–35 (6–10.5)
3
18 (46)
30 (76)
42 (107)
35–60 (10.5–18)
TABLE 8-7
Taxiway Signage Dimensional Specifications
Airport Lighting, Marking, and Signage
Aircraft Approach Category
and (Airplane Design Group)
Visual and Nonprecision
Instrument Runway
Precision
Instrument
Runway
A and B (I and II) small
airplanes only
125 (38)
175 (53)
A and B (I, II, and III)
200 (60)
250 (75)
A and B (IV)
250 (75)
250 (75)
C and D (I through IV)
250 (75)
250 (75)
C and D (V)
250 (75)
280 (85)
C and D (VI)
250 (75)
280 (85)
Perpendicular distance from runway centerline to intersection runway/taxiway centerline
is in feet (meters).
TABLE 8-8
Location Distances for Holding Position Markings
operations. Normally, the larger the sign and the closer it is located to
the runway or taxiway edge the more effective it is. However, aircraft
clearance requirements and jet blast effects require smaller signs
when located near the pavement edges, whereas effectiveness requires
larger signs when located at further distances. The effects of snow
removal operations on the signs should be considered in the choice of
sign size and location. The sign used must provide 12 in of clearance
between the top of the sign and any part of the most critical aircraft
using or expected to use the airport when the wheels of the aircraft
are at the defined pavement edge.
The distances shown in Table 8-8 should be used in determining
runway holding positions. All signs in an array should be of the same
size and at the same height above the ground.
For determining sign locations with respect to intersecting runways, the clearance requirements to other moving aircraft, as given in
Table 8-9, should be used. For signs installed at holding positions the
signs should be in line with the holding line markings within a tolerance
Airplane
Design
Group I
Airplane
Design
Group II
Airplane
Design
Group III
Airplane
Design
Group IV
Airplane
Design
Group V
Airplane
Design
Group VI
44.5 ft
(13.5 m)
65.5 ft
(20 m)
93 ft
(28.5 m)
129.5 ft
(39.5 m)
160 ft
(48.5 m)
193 ft
(59 m)
TABLE 8-9 Perpendicular Distances for Taxiway Intersection Markings from
Centerline of Crossing Taxiway
339
340
Airport Design
of 10 ft. Where there is no operational need for taxiway holding line
markings the signs may be installed in the area from the taxiway
point of tangency to the location where the holding line markings
would be installed [25].
Typical locations for taxiway guidance signs are shown in Fig. 8-37.
An illustration of the required signs and their placement for a basic
airport layout is given in Fig. 8-38 [25].
Sign Operation
Holding positions signs for runways, instrument landing system critical areas, approach areas, and their associated taxiway location signs
should be illuminated when the associated runway lights are illuminated. Other taxiway signs should be illuminated when the associated
taxiway lights are illuminated.
The installation of retroreflective markings is not mandatory. However, it is quite economical, especially at airports where lights cannot be
justified because of the volume or nature of air traffic [12]. The marking
is very similar to that used successfully on highways for many years.
A
E
A
STRAIGHT AHEAD
TAXIWAY
E
A
E
E A A
E
E
E
A
A
(b) STRAIGHT AHEAD TAXIWAY HAS DIRECTION
CHANGE GREATER THAN 25 DEGREES
(a) STANDARD 4-WAY
INTERSECTION
F
F
A
STRAIGHT AHEAD
TAXIWAY
E
E A F
E
E
A F
A
(c) DESIGNATION OF STRAIGHT
AHEAD TAXIWAY HAS CHANGED
A
A
(d) Y CONFIGURATION WITH TAXIWAY
‘A’ CHANGING DIRECTION
FIGURE 8-37 Signage configuration at taxiway intersections.
Airport Lighting, Marking, and Signage
N
G2
7-9
NOTE: DUE TO SPACE LIMITATIONS
ON THIS DRAWING, SOME SIGNS MAY
NOT BE IN THEIR EXACT LOCATION
RELATIVE TO THE RUNWAY OR TAXIWAY.
E
27
9-
HF
INTL
INTL
E
B
D
C B
B
APRON
INTL
B
F
F
F
B
F
TAXIWAY HOLD LINE MARKINGS
TO BE INSTALLED ONLY WHERE
THERE IS AN OPERATIONAL NEED
(SEE AC 150/5340–1)
F
C
G
C
C
NOT TO SCALE
INTL
C
INTL
INTL
INTL
C B
FB
B
B
FIGURE 8-38
D
C
H-27 G
C
D
B
27
B C
ILS CRITICAL
AREA
9-
F
D
E
GH-27
B
B9
ILS
ILS
E
C
B
6
H 6
GH
H
6 H
G
H2 H
7-9
G
APRON
Typical layout of airfield signage.
References
1. Aerodromes, Annex 14 to the Convention on International Civil Aviation, Vol. 1,
Aerodrome Design and Operations, International Civil Aviation Organization,
Montreal, Canada, July 1990.
2. Aerodrome Design Manual, Part 4, Visual Aids, 2d ed., International Civil Aviation
Organization, Montreal Canada, 1983.
3. “Airport Approach, Runway and Taxiway Lighting Systems,” E. C. Walter,
Journal of the Air Transport Division, Vol. 84, No. AT1, American Society of Civil
Engineers, New York, N.Y., June 1958.
4. Airport Design, Advisory Circular, AC 150/5300-13, Federal Aviation
Administration, Washington, D.C., Change 15, 2009.
5. Airport Miscellaneous Lighting Visual Aids, Advisory Circular, AC 150/5340-21,
Federal Aviation Administration, Washington, D.C., 1971.
6. Airway Planning Standard Number One—Terminal Air Navigation Facilities and Air
Traffic Control Services, FAA Order 7031.2B, Federal Aviation Administration,
Washington, D.C., 1976.
7. “Aviation Ground Lighting for All-Weather Operation,” M. Latin, Airport
Forum, Vol. 7, No. 1, February 1977.
8. Comparison Between ICAO Annex 14 Standards and Recommended Practices and
FAA Advisory Circulars, Document No. D6-58344, Boeing Commercial Airplane
Company, Seattle, Wash., 1979.
9. Economy Approach Lighting Aids, Advisory Circular, AC 150/5340-14B, with
Changes 1 and 2, Federal Aviation Administration, Washington, D.C., 1970.
10. Establishment Criteria for Runway End Identification Lights (REIL), Report No.
FAA-ASP-79-4, Federal Aviation Administration, Washington, D.C., 1979.
11. Establishment Criteria for Visual Approach Slope Indicator (VASI), Report No. FAAASP-76-2, Federal Aviation Administration, Washington, D.C., 1977.
12. FAA Specification L-853, Runway and Taxiway Retroreflective Markers, Advisory
Circular, AC 150/5345-39B, Federal Aviation Administration, Washington,
D.C., 1980.
341
342
Airport Design
13. Installation Criteria for the Approach Lighting System Improvement Program (ALSIP),
Report No. FAA-ASP-78-5, Federal Aviation Administration, Washington,
D.C., 1978.
14. Installation Details for Runway Centerline and Touchdown Zone Lighting Systems,
Advisory Circular, AC 150/5340-4C, with Changes 1 and 2, Federal Aviation
Administration, Washington, D.C., 1978.
15. Manual of Surface Movement Guidance and Control Systems, Document No. 9476,
International Civil Aviation Organization, Montreal, Canada, 1986.
16. Marking and Lighting of Unpaved Runways, V. F. Dosch, NAFEC Technical Letter
Report, NA-78-34-LR, Federal Aviation Administration, Technical Center,
Atlantic City, N.J., 1978.
17. Standards for Airport Markings, Advisory Circular, AC 150/5340-1J, Federal
Aviation Administration, Washington, D.C., 1995. Change 1, 2008.
18. Obstruction Marking and Lighting, Advisory Circular, AC 70/7460-1H, Federal
Aviation Administration, Washington, D.C., 1991.
19. Proposed Construction or Alteration of Objects That May Affect Navigable
Airspace, Advisory Circular, AC 70/7460-2I, Federal Aviation Administration,
Washington, D.C., 1988.
20. Precision Approach Path Indicator (PAPI) Systems, Advisory Circular, AC
150/5345-28D, Federal Aviation Administration, Washington, D.C., 1985.
21. Runway and Taxiway Edge Lighting System, Advisory Circular, AC 150/5340-24,
Federal Aviation Administration, Washington, D.C., 1975; and Design and
Installation Details for Airport Visual Aids, Advisory Circular, AC 150/5340-30C,
Federal Aviation Administration, Washington, D.C., 2007.
22. Runway Visual Range (RVR), Advisory Circular, AC 97-1A, Federal Aviation
Administration, Washington, D.C., 1977.
23. Segmented Circle Airport Marker System, Advisory Circular, AC 150/5340-5B,
Federal Aviation Administration, Washington, D.C., 1984.
24. Specifications for Taxiway and Runway Signs, Advisory Circular, AC 150/534544E, Federal Aviation Administration, Washington, D.C., 1991.
25. Standards for Airport Sign Systems, Advisory Circular, AC 150/5340-18D, Federal
Aviation Administration, Washington, D.C., 2004.
26. Taxiway Centerline Lighting System, Advisory Circular, AC 150/5340-19, Federal
Aviation Administration, Washington, D.C., 1968.
27. “The Theory of Visual Judgements in Motion and Its Application to the Design
of Landing Aids for Aircraft,” E. S. Calvert, Transactions of the Illuminating
Engineering Society, Vol. 22, No. 10, London, England, 1957.
28. “Working Papers,” A. E. Jenks, International Air Transport Association, Special
Meeting on Visual Aids to Flare and Landing, Amsterdam, Netherlands,
November 14–22, 1955.
CHAPTER
9
Airport Drainage
A
n adequate drainage system for the removal of surface and
subsurface water is vital for the safety of aircraft and for the
longevity of the pavements. Improper drainage results in the
formation of puddles on the pavement surface, which can be hazardous to aircraft taking off and landing. Poor drainage can also result in
the early deterioration of pavements. Flat longitudinal and transverse
grades and wide pavement surfaces often pose difficulties in making
provision for adequate drainage at airports.
The material in this chapter is principally concerned with estimating
the amounts of surface and subsurface runoff and not with the hydraulics
of pipes or details of installation. These latter items are adequately covered
in texts on hydraulics and literature provided by pipe manufacturers.
The FAA and the Corps of Engineers have developed most of the
information on airport drainage in the United States and the material
presented in this has been drawn from their work. In 2006, several
agencies worked together to combine existing surface drainage topics
covered in several manuals into one Unified Facilities Criteria (UFC)
document. The resulting manual [1] now serves as the design and
analysis standard for surface drainage for the FAA.
Purpose of Drainage
The functions of an airport drainage system are as follows:
1. Interception and diversion of surface and groundwater flow
originating from lands adjacent to the airport
2. Removal of surface runoff from the airport
3. Removal of subsurface flow from the airport
In very few cases will the natural drainage on a site be sufficient by
itself to satisfy these functions; consequently artificial drainage must
be installed.
Design Storm for Surface Runoff
The selection of the severity of the storm which the drainage system
should accommodate involves economic consideration. An extremely
343
344
Airport Design
severe storm occurring very infrequently would undoubtedly cause
some damage if the system were designed for a storm of lesser severity.
However, if serious interruptions in traffic are not anticipated, a system
designed for the larger storm may not be economically justified. Taking
these factors into account, the FAA recommends that for civil airports
the drainage system be designed for a storm whose probability of occurrence is once in 5 years [2]. The design should, however, be checked
with a storm of lesser frequency (10 to 15 years) to ascertain if serious
damage or interruption of traffic would result from such a storm. Drainage for military airfields is based on a 2-year storm frequency [8].
Ordinarily no ponding is permitted on paved surfaces, but in the
intervening areas ponding is permitted, provided it will not result in
undesirable saturation of the subgrades underneath the pavements.
Determining the Intensity-Duration Pattern
for the Design Storm
The determination of the amount of rainfall which can be expected at
the site of the airport is the first step in the design of a drainage system. Rainfall intensity is expressed in inches per hour for various
durations of a particular storm. The expected frequency of occurrence
is also an important factor to consider. The severity of storms is
related to their frequencies; a storm which is expected to occur once
in 100 years will be more severe than one having a frequency of occurrence of once in 5 years.
David L. Yarnell of the U.S. Department of Agriculture conducted
extensive investigations concerning rainfall intensities, durations, and frequencies throughout the United States [16]. West of the 105th meridian,
where the Yarnell information is not as complete, the National Weather
Service has compiled rainfall data which appear in Refs. 12 to 14.
Yarnell developed rainfall intensities for 5-, 10-, 15-, 30-, 60-, and
120-min durations for a storm which can be expected to occur once in
5 years and the intensities for a 1-h duration for storms whose expected
frequencies of occurrence are once in 2, 5, 10, 25, 50, and 100 years.
The intensities for a duration of 1 h for frequencies of 2, 5, 10, 25, 50,
and 100 years are shown in Fig. 9-1.
The 1-h intensity does not by itself portray the intensity-duration
pattern of a storm. The Corps of Engineers made extensive studies of
rainfall patterns in the United States and found that irrespective of
frequency, the intensity-duration patterns of storms were largely
governed by their 1-h intensities. That is, two storms of different
frequency of occurrence whose 1-h intensities are equal will have
similar intensity-duration patterns. This is shown in Fig. 9-2. For
example, if the 1-h intensities of storms whose frequencies were 5,
10, or 15 years were all exactly 2.0 in/h, the intensity-duration patterns would be expected to follow the pattern indicated by the curve
labeled 2.0.
345
FIGURE 9-1
One-hour rainfall intensities for the United States (Corps of Engineers).
346
FIGURE 9-2 Rainfall intensity-duration curves (Corps of Engineers).
Airport Drainage
If the drainage system is to be designed for a storm whose expected
frequency of occurrence is once in 5 years and if detailed data concerning the intensity-duration pattern are nonexistent, the pattern can be
approximated from Fig. 9-2, provided the 1-h intensity is known. It
goes without saying that if sufficient rainfall data are available at an
airport site, the intensity-duration frequency data should be developed from this information rather than from other sources. Rarely,
however, does a site have such complete rainfall information.
Determining the Amount of Runoff by the FAA Procedure
The FAA analysis of airport surface drainage revolves about the solution of the rational method expression
Q = CIA
(9-1)
where Q = runoff from given drainage basin, ft3/s
C = ratio of runoff to rainfall
I = rainfall intensity for time of concentration of runoff, in/h
A = drainage area, acres
Examples and charts illustrating the FAA procedure for design
have been taken largely from the FAA [2].
Time of Concentration
The time of concentration is defined as the time taken by water to reach
the drain inlet from the most remote point in the tributary area. The
most remote point refers to the point from which the time of flow is the
greatest. The time of concentration is usually divided into two components: inlet time and time of flow. The inlet time is the time required
for water to flow overland from the most remote point in the drainage area to the inlet. The time of flow is the time taken by the water to
flow from the drain inlet through the pipes to the point in the system
under consideration. Sometimes the inlet time will be the time of concentration; at other times the time of concentration will be the sum of
the inlet time and time of flow.
The time of flow can be computed by the use of well-established
hydraulic formulas. The inlet time is obtained largely empirically
from the relationship
D = kT2
(9-2)
Where D = distance, ft
T = time, min
k = dimensional empirical factor which is dependent on
slope, roughness of terrain, extent of vegetative cover,
and distance to drain inlet
Inlet times can be estimated from Fig. 9-3.
347
348
Airport Design
FIGURE 9-3
Inlet time curves (Federal Aviation Administration [2] ).
Coefficient of Runoff
Application of the rational method requires the exercise of considerable judgment on the part of the engineer. The runoff rate is variable
from storm to storm and varies even during a single period of precipitation. The coefficient of runoff depends on antecedent storm conditions, slope and type of surface, and extent of the drainage area.
The range of values suggested by the FAA is indicated in Table 9-1.
Airport Drainage
Types of Surfaces
Factor C
For all watertight roof surfaces
0.75–0.95
For asphalt runway pavements
0.80–0.95
For concrete runway pavements
0.70–0.90
For gravel or macadam pavements
0.35–0.70
For impervious soils (heavy)∗
0.40–0.65
For impervious soils with turf∗
0.30–0.55
∗
0.15–0.40
For slightly pervious soils
∗
For slightly pervious soils with turf
∗
0.10–0.30
For moderately pervious soils
0.05–0.20
For moderately pervious soils with turf∗
0.00–0.10
∗
For slopes from 1 to 2 percent.
Source: Federal Aviation Administration [2].
TABLE 9-1
Coefficients of Runoff C
For drainage basins consisting of several types of surfaces with
different infiltration characteristics, the weighted runoff coefficient
should be computed in accordance with
C=
A1C1 + A2C2 + A3C3
A1 + A2 + A3
(9-3)
Typical Example—No Ponding
In order that the worst conditions attendant upon the design storm
may be used in the design of the pipe system, a separate duration of
storm is selected for each subdrainage area tributary to a drain inlet.
The duration of the storm is made equal to the sum of the inlet time
and time of flow.
Each reach of pipe must be designed to carry the discharge from
the inlet at its upstream end plus the contribution from all preceding
inlets. For economy of construction, the grade of each reach is determined largely by topography. A minimum mean velocity on the order
of 2.5 ft/s should be maintained to provide scouring action so that
reduction of the pipe area due to silting will not be a problem.
To clarify the computation of runoff by the FAA method, the following example is presented.
The intensity-duration rainfall pattern for a 5-year-frequency
storm at the site of the proposed airport is shown in Fig. 9-4. The
layout of the drains on a portion of the airport is shown in Fig. 9-5.
Design data for establishing inlet times and coefficients of runoff
349
350
Airport Design
FIGURE 9-4 Intensity-duration rainfall pattern for design storm (Federal Aviation
Administration [2] ).
for drainage areas tributary to drain line A, shown in Fig. 9-5, are
tabulated in Table 9-2. It is assumed that the coefficients of runoff
for pavement and for turf are 0.90 and 0.30, respectively.
From these data, inlet times have been computed by the use of
Fig. 9-3 on the basis that the slope of the pavement is 1 percent and
the slope of the turfed area is 1.5 percent. The inlet times for this specific problem are shown in Fig. 9-3. The computations for runoff,
assuming no ponding, are shown in Table 9-3.
Typical Example—Ponding
In the design of an airfield drainage system, ponding may be used to
effect a reduction in the cost of installation. Ponding is simply a means
of providing temporary storage of runoff prior to its entry into the
underground system. For purposes of design computation, the ponded volume may be assumed to be an inverted pyramid or a truncated
pyramid, the height of which is the depth of water above the inlet at
any stage. The area of the base of the pyramid is taken as the surface
area of the pond. If ponding were permitted, the layout of the drainage
system might be as shown in Fig. 9-6. The most remote point to one of
the inlets is 950 ft, comprising 100 ft of pavement and 850 ft of turf. The
time of concentration is estimated at 4 + 54 = 58 min. The complete
Airport Drainage
FIGURE 9-5 Portion of airport showing drainage design details (Federal Aviation
Administration [2] ).
drainage area is 31.42 acres, of which 6.44 acres is paved. Assuming
that the coefficients of runoff for pavement and turf are 0.90 and 0.30,
respectively, the combined C is 0.423. From Fig. 9-4 the rainfall intensities for durations of 5, 10, 15, 20, 30, 60, 90, 120, and 180 min are obtained,
and the volumes of runoff are computed as shown in Table 9-4.
351
352
Tributary Area to Inlets, acres
Pavement
Turf
Both
Distance Remote Point to Inlet, ft
Subtotal
Pavement
Turf
Total
Line Segment
Length ft
Inlets
5
1.27
1.05
2.32
2.32
200
340
540
5-4
380
5A
1.02
1.86
2.88
2.88
70
450
520
5A-4
440
4
1.40
7.35
8.75
13.95
60
690
750
4-3
420
3
0.78
6.46
7.24
21.19
100
700
800
3-2
440
2
0.83
4.56
5.39
26.58
150
500
650
2-1
380
1
1.14
3.70
4.84
31.42
190
360
550
1-outlet
330
Outlet
—
—
—
330
Total
6.44
—
24.98
—
31.42
—
Weighted Average for C
To inlet 5:
To inlet 5A:
To inlet 4:
1.27
(0.90) = 0.49
2.32
1.02
(0.90) = 0.32
2.88
1.40
(0.90) = 0.14
8.75
1.05
(0.30) = 0.14
2.32
1.86
(0.30) = 0.19
2.88
7.35
(0.30) = 0.25
8.75
C = 0.63
C = 0.51
C = 0.39
To inlet 3:
To inlet 2:
To inlet 1:
0.78
(0.90) = 0.10
7.24
0.83
(0.90) = 0.14
5.39
1.14
(0.90) = 0.21
4.84
6.46
(0.30) = 0.27
7.24
4.56
(0.90) = 0.25
5.39
3.70
(0.30) = 0.23
4.84
C = 0.37
C = 0.39
C = 0.44
Source: Federal Aviation Administration [2].
TABLE 9-2
Design Data for Line A in Fig. 9-5
353
354
Line
Segment
Length of
Segment,
ft
Inlet
Time,
min
Flow
Time,
min
Time of
Concentration,
min
Runoff
Coefficient
C
Rainfall
Intensity
I
Tributary
Area A,
acres
Inlet
5A
5
4
5A-4
5-4
4-3
440
380
420
31.2
30.0
37.7
1.8
1.6
1.1
31.2
30.0
37.7
0.51
0.63
0.39
3.10
3.15
2.80
2.88
2.32
8.75
3
3-2
440
38.9
1.0
38.9
0.37
2.70
7.24
2
1
Outlet
2-1
1-outlet
380
330
34.4
30.7
0.8
0.5
39.9
40.7
0.39
0.44
2.65
2.60
5.39
4.84
Remarks
n = 0.015
See accumulated
runoff computed
below.
Accumulated
runoff adjustment
negligible.
Calculation of Example
Maximum flow from inlets 5 and 5A will reach inlet 4 in 31.6 and 33.0 min, respectively. All inlet 4 subarea will be contributing to the system only after
37.7 min. Flow from inlets 5 and 5A must be adjusted for 37.7-min time of concentration. Adjusted time of concentration for inlets 5 and 5A (that is,
the inlet time for end-of-line structures) equals the time of concentration to inlet 4 less the flow time through the respective pipe segments.
For inlet 5, adjusted time of concentration = 37.7 – 1.6 = 36.1 min. For inlet 5A, adjusted time of concentration = 37.7 –1.8 = 35.9 min. By using these
adjusted times of concentration, an intensity of rainfall of 2.85 in/h is obtained (slight time difference cannot be read from curves).
Applying these data in the formula Q = CIA:
Adjusted flow from inlet 5 = 0.63 × 2.85 × 2.32
= 4.16
Adjusted flow from inlet 5A = 0.51 × 2.85 × 2.88 = 4.18
Flow into inlet 4 from inlets 5 and 5A in 37.7 min = 8.34
Flow from inlet 4 subarea
= 9.56
Accumulated flow entering inlet 4 in 37.7 min
= 17.90 ft3/s
Runoff Q
ft3/s
Accumulated
Runoff, ft3/s
Velocity of
Drain, ft/s
Size of
Pipe, in
Slope of
Pipe, ft/ft
Capacity
of Pipe,
ft3/s
Invert
Elevation
Inlet
5A
5
4
4.55
4.60
9.56
4.55
4.60
17.90
4.0
4.0
6.2
15
15
24
0.008
0.008
0.010
5.0
5.0
20.0
81.52
81.04
78.00
3
7.23
25.13
7.4
27
0.012
30.0
73.80
2
1
Outlet
5.57
5.54
30.70
36.24
8.0
9.5
27
27
0.014
0.020
33.0
37.5
68.52
63.20
56.60
Source: Federal Aviation Administration [2].
TABLE 9-3 Drainage System Design Data
Remarks
n = 0.015
See
accumulated
runoff computed
below.
Accumulated
runoff
adjustment
negligible.
355
356
Airport Design
FIGURE 9-6 Layout of drainage for ponding (Federal Aviation Administration [2] ).
To visualize the effects of ponding, a comparison is made of the
discharge capacity of tentative drainage pipes and the cumulative
runoff for the design storm frequency. This comparison is best made
as a plot of runoff on the ordinate axis and time on the abscissa. An
example of such a plot is shown in Fig. 9-7. The discharge capacity for
each of four selected pipe sizes is shown as a straight line. These discharge curves were computed for an assigned slope and roughness
Airport Drainage
Intensity* I
Q = CIA, ft3/s
5
5.80
77.1
23,100
10
4.96
65.9
39,600
15
4.33
57.5
51,800
20
3.95
52.5
63,000
30
3.18
42.3
76,100
60
2.00
26.6
95,700
90
1.62
21.5
116,300
120
1.26
16.7
120,600
180
0.87
11.6
125,000
Time, min
∗
Volume V = CIAt, ft3
Hourly intensities from Fig. 9-4.
TABLE 9-4
Volume of Runoff—Ponding
FIGURE 9-7 Cumulative runoff for ponding in Fig. 9-6 (Federal Aviation
Administration [2] ).
357
358
Airport Design
coefficient n for each pipe by use of the Manning formula. For this
example the pipes were assumed to be concrete with a roughness
coefficient n of 0.015 and laid on a 1 percent slope. The discharge in
cubic feet per second multiplied by 3600 s is the discharge capacity
ordinate in cubic feet at the 60-min abscissa in Fig. 9-7. Each discharge
capacity curve must pass through the origin of coordinates, and one
point as determined above will define the straight-line relationship.
The significance of the cumulative runoff and discharge capacity
curves as plotted in Fig. 9-7 is that the difference in ordinates (cumulative
runoff minus discharge capacity) represents the amount of ponding at
any instant after the beginning of the storm. The maximum amount of
ponding is determined by scaling the largest difference between the
cumulative runoff curve and the discharge capacity curve.
It is considered essential that all ponding area edges be kept at
least 75 ft from the edges of pavements. In this example, this would
mean that the pond should not reach a level above elevation 88.0. The
storage capacity below this elevation is 161,000 ft3. If a 12-in-diameter
pipe were used, the maximum ponding would amount to 99,260 ft3,
considerably less than the available 161,100 ft3. For practical consideration a pipe of lesser diameter is not recommended.
Although not shown in this text, computations were also made
for a 10-year-frequency storm. With a 12-in-diameter pipe such a
storm would develop a pond of 123,000 ft3, still less than the available
capacity of 161,000 ft3.
Determining the Amount of Runoff
by the Corps of Engineers Procedure
For determining runoff, the Corps of Engineers uses a relationship
for overland flow developed by R. E. Horton [17]. This relationship,
as modified by the Corps of Engineers, is as follows:
1/2
⎡
⎤
⎛ σ⎞
q = (σ tan h2 ) ⎢0 . 922t ⎜ ⎟ S1/4 ⎥
⎝ nL⎠
⎢⎣
⎥⎦
(9-4)
where q = rate of overland flow at lower end of elemental strip of
turfed, bare, or paved surface, in/h of ft3/s per acre of
drainage area
Q = total discharge from a drainage area, ft3/s; Q equals product
of q and drainage area in acres
S = slope of surface or hydraulic gradient, absolute, i.e.,
1 percent = 0.01
t = time or duration, min; time from beginning of supply
(storm); total time t = tc + td
tc = duration of supply which produces maximum rate of outflow from a drainage area but not in a pipe
Airport Drainage
td = time water flows in pipe
σ = rate of supply, or rainfall in excess of rate of infiltration,
in/h
L = effective length of overland or channel flow, ft
n = retardance coefficient
The term tc is nothing more than the time of concentration for the
drainage area under consideration. The term L, the effective length,
represents the length of overland sheet flow from the most remote
point in the drainage area to the drain inlet, measured in a direction
parallel to the maximum slope, before the runoff has reached a defined
channel or ponding basin, plus the length of flow in a channel if one is
present. If ponding is permitted, L is measured from the most remote
point in the drainage area to the mean edge of the pond.
The term n is referred to as the retardance coefficient. Typical coefficients are given in Table 9-5.
When a drainage area is composed of two or three types of surfaces, an average retardance coefficient must be computed. For example, if a drainage area consists of 4 acres of average grass cover and 2
acres of pavement, the average retardance coefficient is equal to
4(0 . 40) + 2(0 . 02)
= 0 . 27
6
Infiltration Rate
Use of the Horton formula requires an estimate of the amount of rainfall which is absorbed in the ground and which therefore does not
appear as runoff. This is referred to as infiltration and is expressed as
a rate in inches per hour. Thus, the intensity of rainfall (in inches per
hour) less the infiltration rate is equal to the rate of runoff or the rate
of supply σ in the formula for runoff.
Surface
Value of n
Smooth pavements
0.02
Bare packed soil free of stone
0.10
Sparse grass cover, or moderately rough bare
surface
0.30
Average grass cover
0.40
Dense grass cover
0.80
Source: Corps of Engineers [8].
TABLE 9-5 Retardance Coefficients
359
360
Airport Design
The infiltration rate is dependent largely on the structure of the
soil cover, moisture content, and temperature of the air. The infiltration rate is not constant throughout the duration of the storm, but is
assumed so in the computations. It is felt that such an assumption is
reasonable, especially when the soil is near saturation.
The infiltration rate for paved surfaces is usually assumed to be
zero. Infiltration rates for other types of surfaces and soil cover must
be estimated from experience. A value of 0.5 in/h has been suggested
for turfed areas. Thus, if the rainfall intensity on a turfed area were
2.0 in/h, the rate of supply σ would be 1.5 in/h.
Standard Supply Curves
By use of Eq. (9-4) maximum rates of runoff q for rates of supply σ of
0.8, 1.0, 1.6, and 1.8 in/h are shown in Figs. 9-8 and 9-9. Maximum
rates of runoff are also shown for rates of supply of 0.4, 0.6, 1.2, 1.4,
2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, and 3.4 in/h [8].
Maximum rates of runoff for the curve labeled supply curve no. 1.0
(Fig. 9-8) were obtained in the following manner. From Fig. 9-2 the
intensities of runoff for various durations corresponding to the curve
labeled 1.0 are obtained. These intensities are entered as σ in Eq. (9-4),
and L is varied to produce the family of curves shown in Fig. 9-8. The
curve labeled σ is supply curve no. 1.0, obtained from Fig. 9-2. The
dotted line labeled tc represents the maximum rate of runoff q which
would occur from an elemental area with various effective lengths L.
For example, the maximum rate of runoff from an area whose effective length L is 60 ft is 2.0 ft3/s. Multiplying this rate by the drainage
area yields the maximum total discharge Q.
Figures 9-8 and 9-9 were prepared for n = 0.40 and S = 1 percent.
If these charts are to be used for other cases, the actual effective L for
the area under study must be converted in terms of L for n = 0.40 and
S = 1. A conversion chart is shown in Fig. 9-10. For example, if the
actual n = 0.30 and S = 2 percent and the effective length L is 400 ft,
then the equivalent effective L for n = 0.40 and S = 1 percent is 140 ft.
Typical Example—No Ponding
In the Corps of Engineers procedure, a reach of drain pipe is always
designed for a storm whose duration is equal to the time of concentration for the drainage area above the pipe. The time of concentration corresponds to the time necessary to produce maximum flow
into a particular inlet (which is the same as the time necessary for
water to reach an inlet from the most remote point in the area) plus
the flow time in the pipe.
To clarify the computation of runoff by the Corps of Engineers
procedure, the following example is presented.
Consider the drainage areas shown in Fig. 9-11. The 1-h intensity
of the design storm is assumed to be 2.0 in/h. The infiltration rate for
the turfed areas is assumed to be 0.5 in/h. The retardance coefficient
Airport Drainage
FIGURE 9-8 Standard supply curves, 0.8 and 1.0 in/h (Corps of Engineers).
for the pavement is n = 0.02, and for the turfed area n = 0.40. The
drainage areas, retardance coefficients (referred to as roughness factors), and actual effective lengths L are shown in Table 9-6. Values of
L and S were obtained from a grading plan of the area. The equivalent
361
362
Airport Design
FIGURE 9-9 Standard supply curves, 1.6 and 1.8 in/h (Corps of Engineers).
Ls are obtained from Fig. 9-10. Column 14, labeled adopted for selecting
diagrams, designates the nearest whole number which can be identified on the supply curves (Figs. 9-8 and 9-9). The standard supply
curve to be used for the example is obtained by weighting the supply
curves for the paved and turfed areas. For example, for inlet 4,
FIGURE 9-10 Modification in L required to compensate for difference in n and S (Corps of Engineers).
363
364
Airport Design
FIGURE 9-11 Portion of airport showing drainage layout (Corps of Engineers).
the paved area is 5.97 acres and the supply curve is 2.0 in/h; the
turfed area is 26.81 acres and the supply curve is 1.5 in/h. The
weighted supply curve is equal to
5 . 97(2) + 26 . 81(1 . 5)
= 1.6
5 . 97 + 26 . 81
In columns 20 and 21, the critical inlet time tc (the time that will produce the maximum discharge) and the corresponding rates of runoff
are listed. These values are obtained from Fig. 9-9. In columns 23 and
24, additional rates of runoff for arbitrarily selected times are listed.
This is done to facilitate computation for various times of concentration for the several points along a drainage system.
The next step is to compute the volumes of runoff into inlets 4, 3,
and 2. The computations are shown in Table 9-7. Obviously the duration of a storm necessary to provide the maximum rate of runoff into
inlet 4 is equal to 24 min. The pipe from inlet 4 to inlet 3 is designed for
a storm of this duration. At inlet 3 the time of concentration is 24 min
plus the flow time in the pipe from inlet 4 to inlet 3 (9.2 min). The pipe
from inlet 3 to inlet 2 would be designed for a storm of 33.2-min duration. Enter Fig. 9-9 (supply curves 1.6) with 33 min as the abscissa, and
read the rates of runoff for effective lengths L of 280 ft (inlet 3) and
330 ft (inlet 4). Multiply these rates by their respective drainage areas.
According to the computations at inlet 3, the area directly tributary to
it contributes 62.5 ft3/s, and the area tributary to inlet 4 contributes
59.0 ft3/s. Thus the pipe from inlet 3 to inlet 2 should be designed for
a capacity of 59.0 + 62.5 = 121.5 ft3/s. The same process would be
repeated for the design of the pipe from inlet 2 to the outlet.
It should be emphasized that the duration of the storm for the
analysis of a particular point along the drainage system always corresponds to the time of concentration above this point. Had the inlet
Airport Drainage
time tc for the area directly tributary to inlet 3 been larger than the
sum of the inlet time for the area tributary to inlet 4 plus the flow time
to inlet 3, the former would have established the duration of the storm
for the design of the pipe from inlet 3 to inlet 2.
Typical Example—Ponding
If ponding is permissible, the first step is to establish the limits of the
ponding area. From a grading and drainage plan, the volumes in the
various ponds can be computed. These volumes are then expressed
in terms of cubic feet per acre of drainage area, as shown in column 9
of Table 9-8. The actual and equivalent L values are determined in
the same manner as for the case of no ponding, with one exception. The
actual L is measured to the mean edge of the pond rather than to the
drain inlet. The actual and equivalent effective lengths are listed in
columns 12 and 13.
The Corps of Engineers has developed charts which yield drain
inlet capacities to prevent ponds from exceeding certain specified
volumes. Typical charts are shown in Figs. 9-12 and 9-13. The volumes are computed for various supply curves (Fig. 9-2), assuming
the slope of the basins forming the drainage areas is 1 percent. The
supply curves represent the intensity-duration pattern for storms
whose 1-h intensities correspond to the supply curve numbers. The
volumes of runoff for a specific supply curve are computed in a
manner similar to the procedure used by the FAA. The cumulative
volumes of runoff are compared with the various capacities of drain
inlets to arrive at the volumes of storage shown in Figs. 9-12 and
9-13. Since the volumes of runoff depend on L and S, charts must be
prepared for a wide range of L values. Figures 9-12 and 9-13 show
drain inlet capacities for L equal to 100, 200, 300, and 400 ft. Additional charts have been prepared for L = 0, 40, 600, 800, 1000, and
1200 ft [8].
The physical significance of the charts may be described by reference to the following example. Suppose that L for a large drainage
area is 100 ft and that the runoff pattern corresponds to supply curve 2.
Assume that the maximum permissible ponding is 300 ft3/acre of
drainage area. From Fig. 9-12 a pipe which has a capacity of 1.0 ft3/s
per acre of drainage area would be adequate to prevent the pond
from exceeding a volume of 3000 ft3 during any part of the storm. The
dashed lines labeled 4 are equal to rates of supply corresponding to a
duration of 4 h. Although smaller drain inlets are possible, it is felt that
the sizes corresponding to a duration of 4 h are about the minimum
from a practical standpoint.
The required drain inlet capacities for the drainage layout in
Fig. 9-11 were obtained from Figs. 9-12 and 9-13 and are tabulated in
Table 9-8. Note that the time of concentration is not a factor in these
computations.
365
Supply Curve Nos.
For paved
areas
2.0
For bare areas
Drainage Section Assuming
1.5
Permissible
Ponding
9
L Adopted for Selecting Diagrams
8
Equivalent L for n = 0.40 and
S = 1%
Volume, ft3/acre DA
7
Actual or Effective Length, ft
Volume 1000 ft3
6
Average Slope S, %
Pond Area, 1000 ft2
Unpaved
Length L, ft
Depth at Inlet, ft
Drainage Area (DA), acres
Average Roughness Factor n
For turfed
areas
Inlet
No.
Paved,
n=
0.02
Bare
Turf n =
0.40
1
2
3
4
5
10
11
12
13
14
4
5.97
26.81
32.78
0.33
2.0
575
330
330
3
5.69
25.54
31.23
0.33
2.8
575
280
280
2
5.69
25.54
31.23
0.33
2.8
575
280
280
Total
Source: Corps of Engineers [8].
TABLE 9-6 Airfield Drainage—Drain Inlet Capacities
Supply Curve Nos.
For paved areas
2.0
For bare areas
Drainage Section
For turfed areas
1.5
Critical Runoff Time to Produce Maximum Flow
in Underground Drain
Drain time, min
Point of Design
Distance, ft
Inlet
or
Junction
From
Main
Outlet
From
Preceding
Inlet
Critical
Inlet
1
2
3
4
4805
3
3155
2
1505
t c,
min
Assumed
Velocity
in Pipe,
ft/s
From
Preceding
Inlet
4
5
6
7
—
4
24
3.0
1650
4
24
3.0
1650
4
24
3.0
Accumulation
Total
Rate of
Approximate tc
(col. 5 +
col. 8)
Adopted
tc, min,
4
3
8
9
10
11
12
24
25
59.0
9.2
9.2
33
30
59.0
62.5
9.2
18.4
42
40
55.8
56.2
Source: Corps of Engineers [8].
TABLE 9-7 Airfield Drainage—Size and Profile of Underground Storm Drains
No Ponding of Runoff
tc, min
qd, ft3/s/acre
Qd, ft.3/s (col. 24 ¥ col. 5)
Critical Contribution to
System
Qd, ft.3/s (col. 21 ¥ col. 5)
tc, min
Weighted Supply Curve
(col. 18 + col. 5)
Unpaved Areas
qd ft3/s/acre
Drain Inlet
Capacity
Standard Supply Curve No. ¥ DA
Paved
Areas
Bare
Turf
15
16
17
18
19
20
21
22
23
24
25
11.94
40.22
52.16
1.6
24
1.8
59.0
30
1.8
59.0
40
1.7
55.8
11.38
38.31
49.69
1.6
23
2.0
62.5
25
2.0
62.5
30
2.0
62.5
40
1.8
56.2
25
2.0
62.5
30
2.0
62.5
40
1.8
56.2
11.38
Total
38.31
49.69
1.6
23
2.0
62.5
Assuming No Ponding of Runoff
Inflow into Underground Drains, ft3/s, Corresponding to Adopted Value of tc (col 10)
Inlet
2
13
Total
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
59.0
121.5
56.2
168.2
368
Airport Design
Supply Curve Nos.
For paved
areas
2.0
For bare
areas
Drainage
1.5
2
5
6
7
8
5.97
26.81
32.78
3.0
138
206
5.69
25.54
31.23
1.73
145
125
5.69
25.54
31.23
2.73
270
368
9
L Adopted for Selecting Diagrams
3
Total
4
Equivalent L for n = 0.40 and
S = 1%
4
Bare
3
Actual or Effective Length, ft
2
Average Slope S, %
1
Turf
n=
0.40
Average Roughness Factor n
Inlet
Paved,
n=
0.02
Volume 1000 ft3
Unpaved
Length L, ft
Volume, ft3/acre DA
Permissible Ponding
Depth at Inlet, ft
Drainage Area (DA), acres
Pond Area, 1000 ft2
For turfed
areas
10
11
12
13
14
6,292
0.33
2.0
525
300
300
4,016
0.33
2.8
340
200
200
11,800
0.33
2.8
340
200
200
∗
Not required when appreciable ponding is permissible.
Source: Corps of Engineers [8].
TABLE 9-8 Airfield Drainage—Drain Inlet Capacities Required to Limit Ponding to Permissible
Volumes
Layout of Surface Drainage
A finished grade contour map of the runways, taxiways, and aprons
is extremely helpful for the layout of a storm drain system. Several
trial drainage layouts may be necessary before the most economical
system can be selected. The grades of the storm drain should be such
as to maintain a minimum mean velocity on the order of 2.5 ft/s to
provide sufficient scouring action to avoid silting. To maintain an
adequate cross section for flow at all times, the diameter of the storm
drain should not be less than 12 in.
Water from a drainage area is collected into the storm drain by
means of inlets. The inlet structure consists of a concrete box, the top
of which is covered with a grate made of cast iron, cast steel, or reinforced concrete. The grates must support aircraft wheel loads and
Airport Drainage
Section East Side of Airfield
19
20
21
22
11.94
40.21
51.15
1.6
∗
0.52
17.05
11.38
38.31
49.69
1.6
∗
0.52
16.24
1.6
∗
0.52
16.24
11.38
38.31
49.69
23
Qd, ft3/s (col. 24 ¥ col. 5)
18
qd, ft3/s/acre
17
Critical Contribution to
System
tc, min
Total
16
Qd, ft.3/s (col. 21 ¥ col. 5)
Turf
15
qd ft3/s/acre
Bare
tc, min
Unpaved Areas
Paved
Areas
Drain Inlet Capacity
Weighted Supply Curve
(col. 18 ÷ col. 5)
Standard Supply Curve No. ¥ DA
24
25
should therefore be designed for contact pressures for the aircraft
which will be served by the airport.
On long tangents, drain inlets are usually placed at intervals
varying from 200 to 400 ft. The location of the inlets depends on the
configuration of the airport and on the grading plan. Normally, if
there is a taxiway parallel to the runway, the inlets are placed in a
valley between runway and taxiways, as indicated in Fig. 9-11.
If there is no parallel taxiway, the drains are placed near the edge of
the runway pavement or at the toe of the slope of the graded area.
The FAA recommends that the inlets not be closer than 75 ft to the
edge of the pavement.
On aprons, inlets are usually placed in the pavement proper. This
is the only way a large apron area can be drained. All grates should
be securely fastened to the frames so that they will not be jarred loose
with the passage of traffic (see Fig. 9-14).
Adequate depths of cover should be provided over the pipes so
that the pipes can support traffic. The recommended minimum
depths of cover are shown in Table 9-9.
369
370
Airport Design
FIGURE 9-12 Drain inlet capacity versus maximum surface storage, L = 100 ft and
L = 200 ft, C.F.S. = cubic feet per second (Corps of Engineers.)
Airport Drainage
FIGURE 9-13 Drain inlet capacity versus maximum surface storage, L = 300 ft and
L = 400 ft, C.F.S. = cubic feet per second (Corps of Engineers.)
371
372
FIGURE 9-14 Recommended pavement drainage sections (Federal Aviation Administration [2] ).
Flexible Pavement
Pipe Cover
Kind of Pipe
Nominal Diameter of Pipe, in
12
18
24
30
Clay sewer pipe
2.5
3.0
3.0
3.5
Clay culvert pipe
1.5
1.5
1.5
2.0
36
42
Nominal Diameter of Pipe, in
48
60
12
18
24
3.5
3.0
3.5
4.0
4.5
4.5
2.0
2.5
3.0
3.0
3.0
3.0
Wheel Load 15,000 lb
30
36
42
48
60
Wheel Load 30,000 lb
Concrete sewer pipe
2.5
3.0
3.0
3.0
3.5
4.0
Concrete sewer pipe
(extra-strength)
1.5
1.5
2.0
2.5
3.0
3.0
Reinforced-concrete culvert pipe
Class I
3.0
4.5
Class II
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
3.0
3.0
3.0
3.0
3.0
3.5
3.5
3.5
Class III
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.5
2.5
2.5
2.5
2.5
2.5
3.0
3.0
Class IV
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Class V
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
2.0
2.0
1.5
2.0
1.0
1.0
1.5
2.0
2.5
1.0
1.0
1.5
1.5
2.0
2.5
2.5
1.0
1.5
1.5
2.0
2.0
2.5
1.0
1.5
1.5
2.0
Corrugated metal pipe, gauge no.
16
1.0
1.5
1.5
14
1.0
1.0
1.0
12
1.0
1.0
10
8
373
TABLE 9-9
1.0
1.0
1.5
1.5
2.0
1.0
1.0
1.0
1.0
1.5
1.5
1.0
1.0
1.0
1.0
Recommended Minimum Depth of Cover for Pipe, ft
374
Flexible Pavement
Pipe Cover
Kind of Pipe
Nominal Diameter of Pipe, in
12
18
24
Clay culvert pipe
3.0
3.5
3.5
Concrete sewer pipe
(extra-strength)
3.0
3.5
3.5
30
36
42
Nominal Diameter of Pipe, in
48
60
12
18
24
3.5
4.0
4.5
3.5
4.0
4.5
Wheel Load 45,000 lb
4.0
30
36
42
48
60
Wheel Load 60,000 lb
4.0
4.5
5.0
Reinforced-concrete culvert pipe
Class I
Class II
3.0
3.5
3.5
4.0
4.0
4.5
4.5
3.5
4.0
4.5
Class III
2.5
3.0
3.0
3.5
3.5
3.5
4.0
4.0
3.0
3.5
4.0
4.0
4.5
Class IV
2.0
2.5
2.5
2.5
2.5
2.5
3.0
3.0
2.5
3.0
3.0
3.0
3.5
3.5
3.5
4.0
Class V
1.5
1.5
2.0
2.0
2.0
2.0
2.5
2.5
2.0
2.0
2.5
2.5
2.5
3.0
3.0
3.0
2.5
3.0
3.5
2.0
2.5
3.0
3.5
4.0
1.5
2.0
2.5
3.0
3.5
4.0
4.0
2.0
2.5
Corrugated metal pipe, gauge no.
16
2.0
2.5
3.0
14
1.5
2.0
2.5
3.0
3.0
12
1.5
2.0
2.0
2.5
2.5
3.0
3.5
1.5
2.0
2.0
2.5
3.0
3.5
1.5
2.0
2.5
3.0
10
8
3.0
3.5
3.5
4.0
2.5
3.0
3.0
3.5
Wheel Load 75,000 lb
Wheel Load 100,000 lb
Reinforced-concrete culvert pipe
Class I
Class II
Class III
3.0
4.0
4.5
4.5
5.0
Class IV
3.0
3.0
3.5
3.5
4.0
4.0
4.5
5.0
Class V
2.5
2.5
3.0
3.0
3.0
3.5
4.0
4.0
4.0
4.5
3.5
4.5
5.0
5.0
5.5
3.5
3.5
4.0
4.0
4.5
5.0
5.0
5.5
3.5
3.5
3.5
4.0
4.5
4.5
4.5
5.0
Corrugated metal pipe, gauge no.
16
3.0
3.5
4.0
14
2.5
3.0
3.5
12
2.5
3.0
10
8
3.0
3.5
4.0
4.5
5.0
2.5
3.0
3.5
4.0
4.5
5.0
3.0
3.5
4.0
4.5
3.5
4.0
4.5
3.0
3.5
4.0
3.0
3.0
3.5
4.0
4.5
5.0
5.5
3.0
3.5
4.0
4.5
5.0
5.5
3.5
4.0
4.5
5.0
Cover depths measured from top of flexible pavement or unsurfaced areas to top of pipe. Cover for pipe in areas not used by aircraft shall be in accordance with cover
requirements for 15,000-lb wheel loads.
Rigid Pavement
Pipe placed under rigid pavements shall have a minimum cover, measured from the bottom of the slab, of 1.0 ft.
Note: The recommended minimum depth of cover for pipe does not provide protection against freezing conditions in seasonal freezing areas.
Source: Federal Aviation Administration [2].
TABLE 9-9
Recommended Minimum Depth of Cover for Pipe, ft (Continued)
375
376
Airport Design
n
Pipe
Clay and concrete
Good alignment, smooth joints, smooth transitions
0.013
Less favorable flow conditions
0.015
Corrugated metal
100% of periphery smoothly lined
0.013
Paved invert, 50% of periphery paved
0.018
Paved invert, 25% of periphery paved
0.021
Unpaved, bituminous-coated or noncoated
0.024
Open channels
Paved
0.015–0.020
Unpaved
Bare earth, shallow flow
0.020–0.025
Bare earth, depth of flow over 1 ft
0.015–0.020
Turf, shallow flow
0.06–0.08
Turf, depth of flow over 1 ft
0.04–0.06
Source: Federal Aviation Administration [2].
TABLE 9-10
Coefficients of Roughness n
As a guide for the design of storm drains, the coefficient of
roughness n for various types of pipes and open channels is listed in
Table 9-10.
Subsurface Drainage
The functions of subsurface drainage are to (1) remove water from a
base course, (2) remove water from the subgrade beneath a pavement, and (3) intercept, collect, and remove water flowing from
springs or pervious strata.
Base drainage is normally required (1) where frost action occurs
in the subgrade beneath a pavement, (2) where the groundwater is
expected to rise to the level of the base course, and (3) where the
pavement is subject to frequent inundation and the subgrade is highly
impervious.
Subgrade drainage is desirable at locations where the water
may rise beneath the pavement to less than 1 ft below the base
course.
Intercepting drainage is highly desirable where it is known that
subsurface waters from adjacent areas are seeping toward the airport
pavements.
Airport Drainage
FIGURE 9-15
Subgrade subdrainage details (Corps of Engineers).
Methods for Draining Subsurface Water
Base courses are usually drained by installing subsurface drains adjacent to and parallel to the edges of the pavement. The pervious material in the trench should extend to the bottom of the base course, as
shown in Fig. 9-15. The center of the drainpipe should be placed a
minimum of 1 ft below the bottom of the base course.
Subgrades are drained by pipes installed along the edges of pavement and in some instances, where the groundwater is extremely
high, underneath the pavements. The center of the subsurface drain
should be placed no less than 1 ft below the level of the groundwater.
When subgrade drains are installed along the edges of the pavement,
they may also serve for draining the base course.
Intercepting drainage can be accomplished by means of open
ditches well beyond the pavement areas. If this is not practical, then
subdrains can be used.
Types of Pipe
The following types of pipe have been used for subdrainage:
1. Perforated metal, concrete, or vitrified clay pipe. The joints
are sealed. The perforations normally extend over about onethird of the circumference of the pipe. The perforated area is
usually placed adjacent to the soil.
2. Bell-and-spigot pipes are laid with the joints open. Vitrified
clay, cast iron, and plain concrete are used in the manufacture
of bell-and-spigot pipes.
377
378
Airport Design
3. Porous concrete pipe collects water by seepage through the
concrete wall of the pipe. This type of pipe is laid with the
joints sealed.
4. Skip pipe manufactured of both vitrified clay and cast iron
is a special type of bell-and-spigot pipe with slots at the
bells.
5. Farm tile is made of clay or concrete with the ends separated
slightly to permit the entrance of water. This type of pipe is
rarely used on airport projects.
Pipe Sizes and Slopes
Experience has shown that a 6-in-diameter drain is adequate, unless
extreme groundwater conditions are encountered. If desired, the
flow may be estimated by means of the available theories for soil
drainage [7]. These theories require knowledge of the effective
porosity and coefficient of permeability of the soil which is being
drained, as well as the head on the pipe and the distance which the
water must flow to reach the drain. Rarely is theory relied on to compute pipe sizes.
The recommended minimum slope for subdrains is 0.15 ft in
100 ft. A minimum thickness of 6 in of filter material should surround
the drain. The gradation of the filter material is discussed in succeeding paragraphs.
Utility Holes and Risers
For cleaning and inspection, utility holes and risers are often installed
along the drains. The Corps of Engineers recommends that utility
holes be placed at intervals of not more than 1000 ft, with one riser
approximately midway between the holes [7]. The function of the
riser is to be able to insert a hose for flushing the system. The function
of a utility hole is to permit inspection of the pipes.
Gradation of Filter Material
The term filter material applies to the granular material which is used
as backfill in the trenches where subdrains are placed. To permit free
water to reach the drain, the filter material must be many times
more pervious than the protected soil. Yet if the filter is too pervious,
the particles of soil to be drained will move into the filter material
and clog it.
On the basis of some general studies conducted by K. Terzaghi,
the Corps of Engineers has developed an empirical design for filter
material which has been substantiated by tests [10]. The criteria for
selecting the gradation of the filter material are as follows:
Airport Drainage
1. To prevent clogging of a perforated pipe with filter material,
the following requirement must be satisfied:
85% size of filter material∗
>1
Diameter of perforation
2. To prevent the movement of particles from the protected
soil into the filter material, the following conditions must be
satisfied:
15% size of filter material
≤5
85% size of protected so
oil
and
50% size of filter material
≤ 25
50% size of protected so
oil
3. To permit free water to reach the pipe, the following condition must be fulfilled:
15% size of filter material
≥5
15% size of protected so
oil
A typical example of design is shown in Fig. 9-16. Concrete sand
has proved to be a satisfactory filter material for the majority of fine
soils which are drainable. A single gradation of filter material is preferred for simplicity of construction.
Filter materials tend to segregate as they are placed in trenches. To
minimize this tendency, the material should not have a coefficient of
uniformity greater than 20. For the same reason, filter materials should
not be skip-graded. Filter materials should always be placed in a moist
state. The presence of moisture tends to reduce segregation.
Drainability of Soils
Certain types of soils, such as gravelly sands, sand, and sandy loams,
are usually self-draining and require very little, if any, subsurface
drainage. Subsurface drainage can be effective for draining clay
loams, sandy clay loams, and certain silty loams. The amount of sand
in these soils largely determines how drainable they are. For soils
containing a high percentage of silt and clay, subsurface drainage
becomes very problematic.
∗This means that 85 percent (by weight) is finer than the specified size.
379
380
Airport Design
FIGURE 9-16
Design example for filter materials (Corps of Engineers).
References
1. Surface Drainage Design, Advisory Circular AC 150/5320-5C, Federal Aviation
Administration, Washington, 2006.
2. Airport Drainage, Advisory Circular AC 150/5320-5B, Federal Aviation
Administration, Washington, 1970.
3. Conduits, Culverts, and Pipes, Engineering Manual EM 1110-2-2902, Department
of the Army, Washington, 1969.
4. “Design of Drainage Facilities for Military Airfields,” G. A. Hathaway,
Transactions, American Society of Civil Engineers, New York, 1949.
5. Drainage and Erosion Control—Drainage for Areas Other than Airfields, Tech.
Manual TM 5-820-4, Department of the Army, Washington, 1965.
6. Drainage and Erosion Control—Structures for Airfields and Heliports, Tech. Manual
TM 5-820-3, Department of the Army, Washington, 1965.
7. Drainage and Erosion Control—Subsurface Drainage Facilities for Airfield Pavements,
Tech. Manual TM 5-820-2, Department of the Army, and Air Force Manual AFM
88-5, Department of the Air Force, Washington, 1979.
8. Drainage and Erosion Control—Surface Drainage Facilities for Airfields and Heliports,
Tech. Manual TM 5-820-1, Department of the Army, and Air Force Manual AFM
88-5, Washington, 1987.
9. Drainage of Asphalt Pavement Structures, Manual Series MS-15, The Asphalt
Institute, College Park, Md., 1984.
10. Filter Experiments and Design Criteria, Tech. Memo 3-360, U.S. Army Corps of
Engineers, Waterways Experiment Station, Vicksburg, Miss., 1953.
11. On-Site Stormwater Management: Applications for Landscape and Engineering, B.
Ferguson and T. H. Debo, 2d ed., Van Nostrand and Reinhold, New York,
1990.
12. “Pavement Subsurface Drainage Systems,” H. H. Ridgeway, Synthesis of
Highway Practice, No. 96, Transportation Research Board, Washington, 1982.
Airport Drainage
13. Precipitation Frequency Atlas of the Western United States, J. F. Miller, National
Weather Service, Washington, 1973.
14. Rainfall Frequency Atlas of the United States, Technical Paper 40, U.S. Weather
Service, Washington, 1961.
15. Rainfall Intensities for Local Drainage Design in the United States, Tech. Paper 24,
pts. 1 and 2, U.S. Weather Service, Washington, 1953, 1954.
16. Rainfall-Intensity Frequency Data, D. L. Yarnell, Miscellaneous Publication 204,
Department of Agriculture, Washington, 1935.
17. “The Interpretation and Application of Runoff Plat Experiments with Reference
to Soil Erosion Problems,” R. E. Horton, Proceedings, vol. 3, Soil Science Society
of America, Madison, Wis., 1938.
18. Urban Hydrology for Small Watersheds, 2d ed., U.S. Soil Conservation Service,
Washington, 1986.
381
This page intentionally left blank
CHAPTER
10
Planning and Design
of the Terminal Area
Introduction
The terminal area is the major interface between the airfield and the
rest of the airport. It includes the facilities for passenger and baggage
processing, cargo handling, and airport maintenance, operations, and
administration activities. The passenger processing system is discussed
at length in this chapter. Baggage processing, cargo handling, and
apron requirements are also discussed relative to the terminal system.
The Passenger Terminal System
The passenger terminal system is the major connection between the
ground access system and the aircraft. The purpose of this system is
to provide the interface between the passenger airport access mode, to
process the passenger for origination, termination, or continuation of
an air transportation trip, and convey the passenger and baggage to
and from the aircraft.
Components of the System
The passenger terminal system is composed of three major components. These components and the activities that occur within them
are as follows:
1. The access interface where the passenger transfers from the
access mode of travel to the passenger processing component. Circulation, parking, and curbside loading and unloading of passengers are the activities that take place within this
component.
2. The processing component where the passenger is processed
in preparation for starting, ending, or continuation of an air
transportation trip. The primary activities that take place within
383
384
Airport Design
this component are ticketing, baggage check-in, baggage claim,
seat assignment, federal inspection services, and security.
3. The flight interface where the passenger transfers from the
processing component to the aircraft. The activities that occur
here include assembly, conveyance to and from the aircraft,
and aircraft loading and unloading.
A number of facilities are provided to perform the functions of
the passenger terminal system. These facilities are indicated for each
of the components identified above.
The Access Interface
This component consists of the terminal curbs, parking facilities, and
connecting roadways that enable originating and terminating passengers, visitors, and baggage to enter and exit the terminal. It includes
the following facilities:
1. The enplaning and deplaning curb frontage which provide
the public with loading and unloading for vehicular access to
and from the terminal building
2. The automobile parking facilities providing short-term and
long-term parking spaces for passengers and visitors, and facilities for rental cars, public transit, taxis, and limousine services
3. The vehicular roadways providing access to the terminal curbs,
parking spaces, and the public street and highway system
4. The designated pedestrian walkways for crossing roads
including tunnels, bridges, and automated devices which
provide access between the parking facilities and the terminal building
5. The service roads and fire lanes which provide access to various facilities in the terminal and to other airport facilities,
such as air freight, fuel truck stands, and maintenance.
The ground access system at an airport is a complex system of
roadways, parking facilities, and terminal access curb fronts. This
complexity is illustrated in Fig. 10-1 which shows the various ground
access system facilities and directional flows at Greater Pittsburgh
International Airport.
The Processing System
The terminal is used to process passengers and baggage for the interface with aircraft and the ground transportation modes. It includes
the following facilities:
1. The airline ticket counters and offices used for ticket transactions, baggage check-in, flight information, and administrative personnel and facilities
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
FIGURE 10-1 Ground access system configuration and directional flows for Greater
Pittsburgh International Airport (Tasso Katselas Associates and Michael Baker Jr.,
Inc. [32]).
2. The terminal services space which consists of the public and
nonpublic areas such as concessions, amenities for passengers and visitors, truck service docks, food preparation areas,
and food and miscellaneous storage
3. The lobby for circulation and passenger and visitor waiting
4. Public circulation space for the general circulation of passengers and visitors consisting of such areas as stairways, escalators, elevators, and corridors
5. The outbound baggage space which is a nonpublic area for
sorting and processing baggage for departing flights
385
386
Airport Design
6. The intraline and interline baggage space used for processing
baggage transferred from one flight to another on the same or
different airlines
7. The inbound baggage space which is used for receiving baggage from an arriving flight, and for delivering baggage to be
claimed by the arriving passenger
8. Airport administration and service areas used for airport
management, operations, and maintenance facilities
9. The federal inspection service facilities which are the areas for
processing passengers arriving on international flights, as well
as performing agricultural inspections, and security functions
The Flight Interface
The connector joins the terminal to parked aircraft and usually
includes the following facilities:
1. The concourse which provides for circulation to the departure lounges and other terminal areas
2. The departure lounge or holdroom which is used for assembling passengers for a flight departure
3. The passenger boarding device used to transport enplaning
and deplaning passengers between the aircraft door and the
departure lounge or concourse
4. Airline operations space used for airline personnel, equipment,
and activities related to the arrival and departure of aircraft
5. Security facilities used for the inspection of passengers and
baggage and the control of public access to passenger boarding devices
6. The terminal services area providing amenities to the public
and those nonpublic areas required for operations such as
building maintenance and utilities
The components of the passenger terminal system together with
the specific physical facilities corresponding to them are shown in
Fig. 10-2. The relative locations of the various physical facilities in the
three level landside building of the midfield terminal complex at
Greater Pittsburgh International Airport are shown in Figs. 10-3, 10-4,
and 10-5. Figure 10-3 shows the enplaning roadway interface with the
departure or check-in level. This level also provides access to the
commuter aircraft departure lounge. Figure 10-4 shows the transit
level which provides airline baggage makeup space, passenger security
processing and access to the automated transit system, the interface
between the landside building and the airside building. Figure 10-5
shows the deplaning roadway interface with the arrivals or baggage
claim level and contains baggage claim facilities and rental car facilities
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Passenger terminal system
Access/Egress
Access/
Processing
Interface
Driving
Riding
Transferring
Enplaning
Deplaning
Parking
Circulating
Highway
Rail right of way
Transfer station
Auto
Taxi
Bus
Train/transit
Enplane curb
Deplane curb
Parking garage
Transit platform
Activity
Physical facility
FIGURE 10-2
Processing
Ticketing
Checking in baggage
Checking passport
Claiming baggage
Checking customs
Ticket counter
Baggage deposit
Passport counter
Bag claim device
Customs counter
Processing/
Flight
Interface
Flight
Assembling
Waiting
Loading
Unloading
Flying
Hold room
Waiting lounge
Mobile lounge
Bus
Loading bridge
Stair/ramp
Aircraft
Components of the passenger terminal system.
as well as a central service building with airport police offices, utility,
maintenance, and storage space. The concourse level of the airside
building is shown in Fig. 10-6. On this level there is a common core with
passenger amenities and four piers providing the departure lounges
and boarding devices at the gates providing the interface with aircraft. One of the four piers is for international arrivals and contains
the sterile areas for customs and immigration functions required for
international passenger processing. The apron level of the airside building is used for airline operations and the lower level provides access to
an automated peoplemover transit system.
Design Considerations
In developing criteria for the design of the passenger terminal complex, it is important to realize that there are a number of different
factors which enter into a statement of overall design objectives. From
these factors general and specific goals are established which set the
framework on which design progresses. For example, in designing
modifications to the apron and terminal complex at Geneva Intercontinental Airport, the general design objectives included [25]
1. Development and sizing to accomplish the stated mission of
the airport within the parameters defined in the master plan
2. Capability to meet the demands for the medium- and longrun time frames
3. Functional, practical, and financial feasibility
4. Maximize the use of existing facilities
387
388
CK
ET
HYATT*
REGENCY
HOTEL
N
&
PA
G
IN
RK
G
L
VA
EA
N
R
TU
R
TO EXTENDED
TERM PARKING
AL
NT
O
TI
P
RE
CE
RE
CA
RE
AR
S
RE
CU
?
PEOPLE MOVER
B
UR
DE
LS
SY
TE
UR
C
VA
RI
CO
AR
M
M
L
IA
C
ER
,
BS
A
,C
NS
VA
B
UR
U
K-
C
O
C
BAGGAGE CLAIM
U
RT
PA
GROUND LEVEL
TRANSIT
ALT.
P
T
AR IN
NE KPO
C
K
HE
TICKETING
RB
ET
ER
NT
U
CO
E
MEZZANINE
SHORT TERM
PARKING
AR
CK
TI
A
LT
DE
NE
MOVING WALKWAY
LONG TERM PARKING
DO
IN
AD
LO
M
LI
PI
POLICE
STATION
SECURITY CHECKPOINT
? INFORMATION DESK
C
ESCALATOR
DEFIBRILLATORS
CO
FIGURE 10-3 Landside building enplaning level at Greater Pittsburgh International Airport (http:// www.pitairport.com).
Ticketing Map
COMMERCIAL CURB
US AIRWAYS BAGGAGE SCREENING
WHEEL CHAIR SERVICE
PUBLIC CURB
FIGURE 10-4 Landside building transit level at Greater Pittsburgh International Airport (http:// www.pitairport.com).
TSA OVERSIZED
BAGGAGE
CHARTER/
AIRCRAFT SERVICE
AIR TRAN
NORTH WEST
CONTINENTAL
SOUTH WEST
DELTA
US AIRWAYS
AMERICA WEST
NORTH
ELEVATOR
USA 3,000
AMERICAN
& AMERICAN EAGLE
& MIDWEST
& MYRTLE BEACH
AIR CANADA
& UNITED
US AIRWAYS
JET BLUE
US AIRWAYS BAGGAGE SCREENING
US AIRWAYS BAGGAGE SCREENING
389
390
Baggage Map
EXPRESS SHUTTLE
B
D
THRIFTY ADVANTAGE
F
ALAMO/ ENTERPRISE
NATIONAL
J
L
K
M
BADGING
OFFICE
NORTH
ELEVATOR
TRAVELERS AID
BOARDING PASS KIOSK
ATM
A
C
AVIS
HERTZ
BUDGET
E
CONVIENCE
STORE
DOLLAR
P
R
VISITOR
CENTER
A US Airways
D Authority/Common Use
J United, Air Canada
M Midwest Connect, American
B US Airways
E Authority/Common Use
K Southwest, Jet Blue, AA
P Myrtle Beech Direct
C Authority/Common Use
F US Airways/Oversized Baggage
L Delta
R USA 3,000, Airtran,
Northwest, Continental,
Authority/Common Use
FIGURE 10-5 Landside building deplaning level at Greater Pittsburgh International Airport (http:// www.pitairport.com).
D88
D86
D89
D87
A9
D84
D82
A7
A5
MEZZANINE
D80
A3
D78
A1
D76
D85
D83
A10
A8
D81
A6
D79
D77
A4
AIRMALL
A2
?
PEOPLE MOVER
B27
C52
C54
C56
C58
C51
C60
INTERNATIONALS
ARRIVALS
C57
B31
B33
B26
B35
B28
C53
C61
B29
B37
B30
C55
CUSTOMS
B32
B34
B36
C59
IMMIGRATION
SECURITY CHECKPOINT
? INFORMATION DESK
ESCALATOR
DEFIBRILLATORS
FIGURE 10-6
Airside building concourse level at Greater Pittsburgh International Airport (http:// www.pitairport.com).
391
392
Airport Design
5. Achievement of a balanced flow between access, terminal,
and airfield facilities during the peak hour
6. Consideration of environmental sensitivity
7. Maintenance of the flexibility to meet future requirements
beyond the current planning horizon
8. Capability to anticipate and implement significant improvements in aviation technology
Specific design objectives were derived from these general objectives which included the needs of the various categories of airport
users. These included
1. Passenger objectives
a. Responsiveness to the needs of the people relative to convenience, comfort, and personal requirements
b. Provision of effective passenger access orientation through
concise, comprehensive directional graphics
c. Separation of enplaning and deplaning roadways and
curb fronts to ensure maximum operational efficiency
d. Provision of convenient access to public and employee
parking facilities, rental car areas, ancillary facilities, and
other on-site facilities
2. Airline objectives
a. Accommodation of existing and future aircraft fleets with
maximum operational efficiency
b. Provision of direct and efficient means of passenger and baggage flow for all passengers, including domestic and international originating, terminating, and transfer passengers
c. Provision for economic, efficient, and effective security
d. Provision of facilities which will embrace the latest energy
conservation measures
3. Airport management objectives
a. Maintenance of the existing terminal operation, access
system, runway system, and ancillary facilities during all
stages of construction
b. Provision of facilities which generate maximum revenues
from concessionaires and other sources
c. Provision of facilities which minimize maintenance and
operating expenses
4. Community objectives
a. Render a unique and appropriate expression and impression of the community
b. Provision of harmony with the existing architectural elements of the total terminal complex
c. Coordination with the existing and planned off-airport
highway system
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
The designer should consider the combination of these types of
objectives in developing specific design criteria for the passenger terminal complex. These criteria should be used as performance measures for the evaluation of design alternatives. In order to generate
performance measures, a detailed design should be provided. The
analyst can then proceed to calculate the various performance measures using a number of analytical techniques. Some of these techniques are discussed later in this chapter.
Terminal Demand Parameters
The determination of space requirements at passenger terminals is
strongly influenced by the quality of service desired by the various
airport users and the community. A review of passenger terminals in
relation to passenger volumes at existing airports shows a wide range
in the configuration and the amount of area provided per passenger.
However, some guidelines for the determination of space requirements
can be defined. The purpose of these guidelines is to give general
orders of magnitude for values that are subject to change depending
on the requirements of specific designs.
The following steps should be followed in determining terminal
facility space requirements.
Identify Access Modes and Modal Splits
Vehicle volumes are normally derived from projections of passenger
and aircraft forecasts. These volumes critically impact the design of
highway access facilities, on-airport roadway and circulation systems, curb frontage requirements for private automobiles, buses, limousines, taxis, and rental cars, and parking. Surveys are normally
conducted to determine the access modes of passengers and vehicle
occupancy rates [26]. In the absence of such surveys, secondary
sources may be investigated to ascertain the access characteristics of
passengers in similar airport environments [24, 55, 60].
The most important parameters to be obtained include the typical
peak hour volumes of vehicles entering and leaving the airport on the
design day, the access facilities used and the duration of use, including parking and curb front. Care should be exercised to include
employees and visitors as well as passengers in these access studies,
and to correlate the peaking characteristics and access modes of each
group of airport traveler.
Identify Passenger Volumes and Types
Passenger volumes can be obtained from forecasts normally done in
conjunction with airport planning studies. Two measures of volume
are used. The first is annual passenger volume, which is used for preliminary sizing of the terminal building. The second is a more detailed
hourly volume. It is customary to use typical peak hour passengers as
the hourly design volume for passenger terminal design. This parameter
393
394
Airport Design
is a design index and is usually in the range of 0.03 to 0.05 percent of
the annual passenger volume but it is significantly affected by the
scheduling practices and fleet mix of the airlines.
The identification of passenger types is necessary because different types of passengers place different demands on the various components. Passenger types are usually broadly classified into domestic
and international passengers and then further grouped into originating, terminating, connecting or transfer, through, enplaning and
deplaning passengers. These various groupings of passengers are
made on the basis of the facilities within the terminal which are normally used by each type of passenger. Airports which are used as
airline hubs and have a high proportion of connecting passengers
require considerably less ground access and landside facilities than
airports with a high proportion of originating and terminating passengers. Historical data and forecasts regarding the proportions of
the total volumes that are made up by each of the different types of
passengers are useful in obtaining estimates of the parameters needed
for the design of the various facilities [4, 58].
Identify Access and Passenger Component Demand
This is done by matching the passenger and vehicle types with facilities in the terminal area. The use of tabulations such as the one shown
in Table 10-1 is quite helpful. This table shows which passengers are
using which facility. By indicating the volume of each type of passenger
in the rows corresponding to the facilities, it is possible to generate
the total load on each facility. This is done by taking the row sums of
the volumes entered.
Facility Classification
The airport terminal facility may be classified by its principal characteristics relative to its functional role. In general, airports are classified as originating-terminating, transfer, or through airports. The
facilities required are considerably different in magnitude and configuration for each.
An originating-terminating airport processes a high level of passengers which are beginning or ending the air transportation trip at
the airport. At such airports these passengers may be in the order of
70 to 90 percent of the total passengers. These airports can have a
relatively long aircraft ground time for long haul international flights
but also may have relatively short ground times for domestic
operations and operations by low-cost air carriers. In either case, the
main flow of passengers is between the aircraft and the ground
transportation system and have relatively high requirements for
curb frontage, ticketing and baggage claim facilities, and parking.
Typical data indicate that the hourly movements of aircraft per gate
at such airports can range from on the order of 1.0 to nearly 3.0 operations
per hour per gate.
Passenger Type i, Arriving
Passenger Type i, Departing
Facility j
Domestic,
No Bags,
Auto
Driver*
Domestic,
with Bags,
Auto
Passenger†
International,
with Bags,
Auto
Passenger
Domestic
with Bags,
Auto
Passenger
Curb, arrivals
–
Vij‡
Vij
Curb, departures
–
–
–
Domestic lobby
–
Vij
International lobby
–
Ticketing counter
Domestic,
No Bags,
Auto Driver
International,
with Bags,
Auto Driver
–
–
–
Vij
–
Vij
–
Vij
Vij
–
–
–
–
–
Vij
–
–
–
Vij
–
Vij
Assembly
–
–
–
Vij
–
Vij
Baggage check-in
–
–
–
Vij
Vij
Vij
Security control
–
–
–
Vij
Vij
Vij
Customs, health
–
–
Vij
–
–
–
Immigration
–
–
Vij
–
–
Vij
Baggage claim
–
Vij
Vij
–
–
–
*Auto driver = passenger driving a car to and from airport.
Auto passenger = passenger driven to and from airport.
‡
Vij = design volume of passenger type i using facility type j.
†
TABLE 10-1 Determination of Demand for Various Types of Passenger Facilities
Total
Volume V
395
396
Airport Design
A transfer or connecting airport, on the other hand, has a high
percentage of its total passengers connecting between arriving and
departing flights. Today many airports in the United States are connecting airports particularly those that are airline hubs. These airports
need greater concourse facilities for the processing of connecting passengers and less ground access facility development. Airline ticketing
positions and baggage claim facilities are usually less than with originating airports (on a size per passenger basis). However, intraline
and interline baggage facilities are usually greater. Care must be exercised in the planning of such airports to locate the gate positions of
airlines exchanging passengers in close proximity to each other to
minimize central terminal flows and connecting times. Data indicate
that such airports demonstrate aircraft activity at the rate of 1.3 to 1.5
aircraft per gate per hour in peak periods.
The through airport combines a high percentage of originating passengers with a low percentage of originating flights. A
high percentage of the passengers remain on the aircraft at such
points. Aircraft ground times are minimal, averaging between 1.6
and 2.0 hourly movements per gate in peak periods. Departure
lounge space, curb frontage, ticketing, security, and baggage facilities are less than at originating airports.
Overall Space Approximations
It is possible to estimate order of magnitude ranges for the overall
size of a terminal facility prior to performing more detailed calculations for particular space needs. These estimates allow the planner to
broadly define the scope of a project based upon information which
summarizes the space provided of other existing facilities.
The FAA has indicated that gross terminal area space requirements
of between 0.08 and 0.12 ft2 per annual enplaned passenger are reasonable. Another estimate is obtained by applying a ratio of 150 ft2 per
design hour passenger [43]. Estimates of the level of peak hour passengers, peak hour aircraft operations, and gate positions are also obtained
based upon the level of annual enplanements using relationships such
as those shown in Fig. 10-7. Others have provided estimating guidelines
for total terminal space as shown, for example, in Fig. 10-8 [43].
Approximations of the allocation of space among the various
purposes in a terminal building are also useful for preliminary planning. The FAA indicates that approximately 55 percent of terminal
space is rentable and 45 percent is non-rentable [49]. An approximate
breakdown of these space allocations typically is 35 to 40 percent for
airline operations, 15 to 25 percent for concessions and airport administration, 25 to 35 percent for public space, and 10 to 15 percent for
utilities, shops, tunnels, and stairways. A final determination of the
actual space allocations is obtained through detailed analyses of the
performance of the elements of the system as the design process
120
14
100
13
Peak hour
operations
80
12
Number
of gates
60
11
40
10
Peak hour passengers
20
9
2
0
4
6
8
10
12
14
16
18
8
20
Percentage of daily passengers in peak hour
Operations or gates
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Annual enplaned passengers, millions
Gross terminal area per gate
(000 SF building area)
FIGURE 10-7 Estimated peak hour passenger, operations, and gate requirements
for intermediate range planning (Federal Aviation Administration [43]).
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
0 2 4 6 8 10
20
30 40 50 60 70 80 90 100 110 120 130 140
Annual enplanements, millions
FIGURE 10-8 Gross terminal area estimates for intermediate range planning
(Federal Aviation Administration [49]).
proceeds from space programming through each of the subsequent
phases in the process.
Level of Service Criteria
Considerable research and discussion has taken place in the profession relative to the adoption of level of service standards and associated criteria to evaluate the level of service afforded in the design of
397
398
Airport Design
landside processing systems. Although it is relatively simple to
develop relationships between aircraft delay on the airside and its
economic consequences, such relationships are difficult to either
define or develop on the airport landside. Much of the difficulty
is related to the fact that the various constituent groups associated with airports view quality of service or level of service from
different perspectives [37]. Airlines are concerned with such factors as on-time schedules, the allocation of personnel, airport
operating costs, and profitability. Passengers are concerned with
the completion of an air transportation trip at a reasonable cost,
with minimum delay and maximum convenience, without being
subjected to excessive levels of congestion. The airport operator
is interested in providing a modern airport facility which meets
airline and passenger objectives in harmony with the expectations of the community in which the airport is located. Given the
number of possible measures of service quality and the differences in airports throughout the country, it is very difficult to
adopt level of service criteria on a broad scale.
Many have examined level of service criteria for airports and
attempted to define level of service standards [9, 11, 14, 16, 21, 29, 31,
36, 37, 41, 45, 56]. In general, the level of service measures commonly
associated with the airport landside system include measures of congestion within the terminal building and the ground access system,
passenger delays and waiting line lengths at the various facilities in
the terminal building, passenger walking distances, and total passenger processing time. Most of these parameters can be evaluated in a
terminal design with the aid of mathematical modeling. However,
the various measures of level of service from the perspective of
airport users must be balanced in reaching some acceptable solution
to the design problem.
As an illustration of the application of a level of service standard, let us say that an airline may desire to limit the percentage of
its passengers which must spend more than some increment of
time at an airport check-in facility. One could develop a model
which computes the percentage of passengers at the check-in facility for various durations of time when the number of check-in
counters operated is varied for some peak hour passenger demand
[35]. As an example, the results could be shown graphically as is
done in Fig. 10-9. From this illustration, if the criteria were to limit
the percentage of passengers spending more than 5 min at this
facility to 10 percent, then it would have been necessary for the
airline to operate nine check-in counters at the airport during the
peak hour.
Such formulations can be examined for the various facilities
within the airport landside to obtain quantitative measures of component and system performance. These are discussed later in this
chapter.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Probability of Being in System
Longer Than Time Indicated
100
80
k=7
60
k=8
40
k=9
20
0
0
2
4
6
8
10
12
14
Total Time in System (minutes)
16
18
20
FIGURE 10-9 Impact of the number of check-in counters (k) on passenger time at a
check-in facility.
The Terminal Planning Process
The evolution and development of a terminal design is performed in
a series of integrated steps. These may be identified as programming,
concept development, schematic design, and design development.
The terminal facilities are developed in conformity with the planned
development of the airside facilities considering the most effective
use of the airport site, the potential for physical expansion and operational flexibility, integration with the ground access system, and compatibility with existing and planned land uses near the airport. The
planning process explicitly examines physical and operational aspects
of the system.
The programming phase defines the objectives and project scope
including the rationale for the initiation of the study. It includes a
space requirements program, tentative implementation schedules,
estimates of the anticipated level of capital investment as well as
operating, maintenance, and administrative costs. In concept development, studies are undertaken to identify the overall arrangement
of building components, functional relationships, and the characteristics of the terminal building. Schematic design translates the concept and functional relationships into plan drawings which identify
the overall size, shape, and location of spaces required for each function. Detailed budget estimates are prepared in schematic design so
that comparisons may be made between the space requirements and
costs. In design development, the size and character of the entire project is determined and detailed plans of the specific design and allocation of space within the complex are prepared. This phase forms the
399
400
Airport Design
basis for the preparation of construction documents, bidding, construction, and final project implementation [50].
In the programming and concept development phases of a terminal design project, the following evaluation criteria are typically used
to weigh alternatives:
1. Ability to handle expected demand
2. Compatibility with expected aircraft types
3. Flexibility for growth and response to technology changes
4. Compatibility with the total airport master plan
5. Compatibility with on-airport and adjacent land uses
6. Simplicity of passenger orientation and processing
7. Analyses of aircraft maneuvering routes and potential conflicts on the taxiway system and in the apron area
8. Potential for aircraft, passenger, and vehicle delay
9. Financial and economic feasibility
In the schematic and design development phases, more specific
design criteria are examined such as:
1. The processing cost per passenger
2. Walking distance for various types of passengers
3. Passenger delays in processing
4. Occupancy levels and degree of congestion
5. Aircraft maneuvering delays and costs
6. Aircraft fuel consumption in maneuvering on the airport
between runways and terminals
7. Construction costs
8. Administrative, operating, and maintenance costs
9. Potential revenue sources and the expected level of revenues
from each source
Space Programming
The space programming phase of terminal planning seeks to establish gross size requirements for the terminal facilities without establishing specific locations for the individual components. The nature
of the processing components is such, however, that approximate
locations are indicated for new and existing terminal facilities due to
the sequential nature of the processing system. This section provides
guidance concerning the spatial requirements to adequately accommodate the several functions carried out within the various areas of
the airport terminal.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
The Access Interface System
The curb element is the interface between the terminal building and
the ground transportation system. A survey of the airport users will
establish the number of passengers using each of the available ground
transportation modes such as private automobile, taxi, limousine,
courtesy car, public bus, rail, or rapid transit. Ratios may be established for both the passenger and vehicle modal choice for airport
access.
Terminal Curb
The length of curb required for loading and unloading of passengers and
baggage is determined by the type and volume of ground vehicle traffic
anticipated in the peak period on the design day. Airports with relatively
low passenger levels may be able to accommodate both enplaning and
deplaning passengers from one curb front. Airports with higher passenger levels may find it desirable to physically separate the enplaning from
the deplaning passengers, horizontally, if space permits, or vertically if
space is limited. There is a tendency at large airports to also separate
commercial vehicle traffic from private vehicle traffic.
The determination of the amount of curb space which will be
required is related to airport policies relative to the assignment of
priorities to the use of curb front and the provision of staging areas
for taxis, buses, and other public transport vehicles. The parameters
required for a preliminary analysis of curb front needs are the number
and types of vehicles at the curb, the vehicle length, and the various
occupancy times of different types of vehicles at the curb front for
arriving and departing passengers.
Normally, a slot for a private automobile is considered to be about
25 ft, whereas for taxis 20 ft, limousines 30 ft, and transit buses 50 ft
are used. Reported dwell times for private automobiles range from
1 to 2 min at the enplaning curb and from 2 to 4 min at the deplaning
curb. Taxi dwell times lie closer to the lower range of these values,
whereas limousines and buses may be at the curb anywhere from 5 to
15 min. These dwell times are highly influenced by the degree of traffic regulation and enforcement in the vicinity of the curb, and should
be verified in specific studies. Normally a wide lane, in the order of
18 to 20 ft, is provided to accommodate direct curb access, maneuvering, and standing vehicles. This usually indicates a minimum of one
and preferably two additional lanes in the vicinity of terminal
entrances and exits to provide adequate capacity for through traffic.
Rules of thumb which may be applied to determine curb front needs
indicate that the full length of the curb adjacent to the terminal plus
about 30 percent of the maneuvering lane may be considered as the
available curb front. Therefore, a 100-ft curb may be considered to
provide 130 ft of curb front in 1 h or 7800 foot-minutes of vehicle
occupancy. If 120 automobiles per hour demand curb space for an
401
402
Airport Design
average dwell time of 2 min, then 6000 foot-minutes of curb front is
required, or the peak hour must provide a curb length of 100 ft. Other
methods for approximating curb frontage have been reported in the
literature [12, 43, 52, 58, 60].
Roadway Elements
The determination of the vehicular demand for the various on and off
airport roadways is essential to ensure that adequate service levels
are provided airport users. The main components of the highway system providing for access to airports from population and industrial
centers is normally within the jurisdiction of federal, state, and local
ground transportation agencies. However, coordination in area-wide
planning efforts is essential so that the traffic generation potential of
airports may be included within the parameters necessary for the
proper planning of regional transportation systems. Guidance on the
level and peaking characteristics of airport destined traffic may be
found in the literature [55, 60].
The provision of adequate feeder facilities from the regional
transport network to the airport is largely within the jurisdiction of
the airport operator or owner. Vehicle volumes and peaking characteristics are usually determined by correlating modal preference and
occupancy rates with flight schedules. Normally roadway facilities
are designed for the peak hour traffic on the design day with adequate provision for the splitting and recirculation of traffic within
the various areas of the airport property. The main roadway elements which must be considered are the feeder roads into the terminal area, the enplaning and deplaning roadways, and recirculation
roadways.
The Highway Capacity Manual [33] provides criteria for level of
service design and quantitative methods for determining the volumes which can be accommodated by various types of roadway sections. Unfortunately little guidance is available for the level of service
design of airport roadways. For preliminary planning, however, it is
reasonable to assume that feeder roads on the airport property provide acceptable service when they are designed to accommodate
from 1200 to 1600 vehicles per hour per lane. Roadways providing
access to the enplaning and deplaning terminal systems provide adequate service when they are designed to accommodate from 900 to
1000 vehicles per hour per lane. Terminal frontage roads and recirculation roads, however, provide adequate service when they are
designed to accommodate from 600 to 900 vehicles per hour per lane.
It is recommended that for preliminary planning purposes the above
ranges of values be used to establish bounds on the sizes of these facilities for a demand-capacity analysis. In schematic design, analysis of
the flow characteristics of individual sections of the roadway elements will yield final design parameters.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Parking
Most large airports provide separate parking facilities for passengers
and visitors, employees, and rental car storage. In smaller airports
these facilities may be combined in one physical location. Passenger
and visitor parking are often segregated into short-term, long-term,
and remote parking facilities. Those parking facilities most convenient to the terminal are designated as short term and a premium rate
is charged for their use. Long-term parking is usually near the main
terminal complex, but not as convenient as short term, and rates are
usually discounted for long-term users. Remote parking, on the other
hand, is usually quite distant from the terminal complex and provisions are normally made for courtesy vehicle transportation between
these areas and the main terminal complex. The rates in these facilities are usually the most economical.
Short-term parkers are normally classified as those which park
for 3 h or less and these may account for about 80 percent of the
parkers at an airport. However, these short-term parkers account
for only 15 to 20 percent of the accumulation of vehicles in the
parking facility [43]. Preliminary planning estimates of the number of parking spaces required at an airport may be obtained from
Fig. 10-10. The range of public parking spaces provided at existing
airports varies from 1000 to 3000 per million originating passengers.
Public auto parking spaces
5,000
4,000
3,000
2,000
1,000
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Originating passengers, millions
FIGURE 10-10 Public automobile parking space requirements (Federal
Aviation Administration [49]).
403
404
Airport Design
It is recommended, however, that the range for preliminary planning be established between 1000 and 1400 parking spaces per million originating passengers.
More refined estimates of the total amount of parking required
and the breakdown of short- and long-term space is obtained from
analyses performed in the schematic design phase of the terminal
planning process.
Entrances to parking facilities through ticket spitting devices are
very common at airports. It has been observed that these devices can
process anywhere from 400 to 650 vehicles per hour depending upon
the degree of automation used as well as the continuity of the demand
flow. It is recommended that the number of entrances be estimated on
the basis of 500 vehicles per hour per device in preliminary planning.
Parking revenue collection points at parking facility exits process
from 150 to 200 vehicles per hour per position.
In parking garages, the capacity of ramps leading from one level
to another is important during peak periods when considerable
searching for an available space may occur, or vehicles may be
directed immediately to a particular level. One-way straight ramps
can accommodate about 750 vehicles per hour. However, a reduction
in the order of 20 percent should be considered when two-way ramps
are utilized. Circular or helical ramps, often used for egress from
parking facilities, accommodate about 600 vehicles per hour in one
direction.
The precise volume of vehicles which may be accommodated by a
particular design will depend to a large extent on the geometric characteristics of the design, continuity of flow, information systems
installed, and characteristics of the vehicles and users of the particular
facility [22, 40, 60]. Most often, some type of analytical or simulation
model is used in the schematic design phase of the project to test a
preliminary design.
The Passenger Processing System
The passenger processing system consists of those facilities necessary
for the handling of passengers and their baggage prior to and after a
flight. It is the element which links the ground access system to the air
transportation system. The terminal curbs provide the interface on
the ground access side of the system, and the aircraft gates devices
provide the interface on the airside of the system. In determining the
particular needs of a specific component in this system, knowledge of
the types of passengers and the extent of visitors impacting on each
component is necessary.
Entryways and Foyers
Entryways and foyers are located along the curb element and serve
as weather buffers for passengers entering and leaving the terminal
building. The size of an entryway or foyer depends upon its intended
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
usage. As entrances and exits may be relatively small, sheltered public waiting areas should be provided and sized to meet local needs.
Designs must accommodate the physically challenged. These facilities are sized to process both passengers and visitors during the peak
hour. Although the time of the enplaning and deplaning peaks may
be different, it is likely that the deplaning peak will occur over a
shorter time duration than the enplaning peak. It is often useful to
subject a preliminary design proposal not only to an average peak
hour demand but also a peak 20 or 30 min demand, particularly for
the deplaning elements of the system. Preliminary design processing
rates for automated doors in the vicinity of the enplaning and deplaning curb front can be taken as from 8 to 10 persons per minute per
unit. These values may be reduced by 50 percent if the doors are not
automated.
Terminal Lobby Area
The functions of significance to an air traveler performed in a terminal lobby are passenger ticketing, passenger and visitor waiting, and
baggage check-in and claiming. Airports with less than 100,000
annual enplanements frequently carry out these functions in a single
lobby. More active airports usually have separate lobbies for each
function. The size of the lobby space depends on whether ticketing
and baggage claim lobbies are separate, if passenger and visitor waiting areas are to be provided, and the density of congestion acceptable.
In general, the lobby area should provide for passenger queuing, circulation, and waiting. Waiting lobby areas are designed to seat from
15 to 25 percent of the design hour enplaning passengers and visitors
if departure lounges are provided for all gates, and from 60 to 70 percent
if they are not provided [43, 50]. Usually about 20 ft2 per person is
provided for seating and circulation.
Airline Check-In Counter and Ticket Office
The airline check-in counter and ticket office is the area at the airport
where the airline and passenger make final ticket transactions and
check-in baggage for a flight. This includes the airline check-in counter, airline ticket agent service area, outbound baggage handling
device, and support office area for the airline ticket agents. There are
three types of ticketing and baggage check-in facilities, the linear,
pass through, and island types. Each of these facilities is shown in a
typical arrangement in Fig. 10-11.
The check-in transaction takes place at the check-in counter, which
is a stand-up desk. To the left and right of the ticket counter position, a
low shelf is provided to deposit, check-in, tag, and weigh baggage, if
necessary, for the flight. Subsequently, the baggage is passed back by
the agent to an outbound baggage conveyance device located near the
counter for security screening, sorting, and loading on the aircraft.
405
406
Airport Design
Conveyor
Bag well
Counters
Linear
Counters
Conveyor
Island
Counters
Counter
Counter
Pass through
Conveyor
Conveyor
FIGURE 10-11 Typical check-in counter configurations (Federal Aviation
Administration [49]).
The total number of check-in counter positions required is a
function of the level of peak hour originating passengers, the types
of facilities provided (i.e., multipurpose, express baggage check-in,
and ticketing only) and the queues and delays acceptable to the
airlines. In some markets, a considerable number of passengers may
be preticketed and a higher percentage of express check-in positions may be warranted either within the terminal building or at the
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
curb front. This is particularly true at airports serving tourist areas.
A reasonable estimate of the number of positions required is gained
by assuming the peak loading on the facilities is about 10 percent of
the peak hour originating passengers and that a maximum queue
length of five passengers per position is a desirable design goal. If this
is the case, then 3000 peak hour originating passengers, translates to
300 peak loading passengers, which requires 60 ticketing positions. The
sizing of the counter length depends on the mix of position types, but
for preliminary estimating purposes a counter length from 10 to 15 ft for
two positions is reasonable. Therefore, in this case the total linear footage of counter space would range from 300 to 450 ft. If a queuing depth
of 3 ft per passenger is provided, then a minimum queuing depth of
15 ft is required. The counter itself requires a 10-ft depth and a circulation aisle of from 20 to 35 ft is appropriate. Therefore, the area devoted
to this function ranges from about 13,500 to 27,000 ft2. If single row
lobby seating is provided in the area, this increases the area to between
16,500 to 30,000 ft2. Approximations gained from other techniques yield
similar results [12, 50].
The above calculations are useful for linear type counters where
queues form in lines at each position. For corral type queuing similar
results are obtained, the principal advantage of this type of queuing
being less restriction to circulation in the ticket lobby area. The
pass-through and island type counters result in a similar number of positions and counter length but in different geometric arrangements. The
circulation and queuing areas may be modified as shown in Fig. 10-11.
Normally, in pass-through ticketing and baggage check-in facilities,
queuing is along the length of the counter whereas in island types queuing is in lines at the various ticketing positions.
The final determination of the number and mix of check-in
positions is made through consultation with the various airlines to
be served and through the use of analytical or simulation models
[15, 58]. Figure 10-12 shows the terminal lobby area and airline
check-in counters at the Pittsburgh International Airport.
The airline ticket office (ATO) support area may be composed of
smaller areas for the operations and functions of accounting and safekeeping of tickets, receipts, and manifests; communications and
information display equipment; and personnel areas for rest, personal grooming, and training. On the wall behind the ticket agents
are posted information displays for the latest airline information on
arriving and departing flights. Typical estimates of ATO space
requirements may be obtained by taking the linear footage of counter and multiplying this by a depth of from 20 to 25 ft for this area.
This yields a value of from about 6000 to 11,000 ft2 for 3000 peak
hour originating passengers. As the level of peak hour passengers
increases various economies of scale may be gained in the use of
such facilities. For example, in moving from 3000 to 6000 peak hour
407
408
Airport Design
FIGURE 10-12 Terminal lobby and airline check-in counters at the Pittsburgh
International Airport.
originations, the increase in ATO space may be only about 30 percent. Other estimating procedures yield similar results [43, 50].
Again, the final determination of the space requirements is obtained
through consultation with the various airlines using the facility.
The proliferation of self-service check-in kiosks at airports, along
with the increasing ability for passengers to check-in for flights using
the Internet or mobile device has created new challenges for check-in
area planning and design. It is clear that there will always be a need for
traditional check-in stations staffed by airline personnel. However, the
number of staffed stations is becoming smaller compared to the number of installed self-service kiosks.
The implementation of self-service kiosks that have the capability
of providing check-in service to more than one air-carrier, known as
CUSS—“common use self-service” kiosks are helping to redefine the
check-in spacing needs in airport terminals. These CUSS systems
may be placed throughout the terminal entry lobby for all passengers
to use, regardless of their individual airlines.
Passenger Security Screening
Security screening of passengers is an extremely important function in
an airport terminal. The security screening area will include a checkpoint for identification inspection, walk-through metal detectors, and
x-ray equipment for carry-on baggage inspection. The location and
size of the screening area will be dictated primarily by passenger
volume with consideration to issues of queuing, physical search, and
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
passengers requiring additional processing. The equipment, techniques, and procedures may vary with location and are subject to
change at any time. A few years ago, greeters, wellwishers, and visitors could be processed at the security area and proceed to the gate
areas, but today only ticketed passengers are permitted in the sterile
area. In the United States, the Transportation Security Administration
(TSA) has prepared extensive guidelines and space planning and
analysis tools [57] to assist planners in the design of the security
screening area and these are introduced in Chapter 11.
Departure Lounges
The departure lounge serves as an assembly area for passengers waiting to board a particular flight and as the exit passageway for deplaning passengers. It is generally sized to accommodate the number of
boarding passengers expected to be in the lounge 15 min prior to
scheduled departure time, assuming this is the point in time when
aircraft boarding begins. A conservative estimate of the percentage
of passengers in the lounge at this time is 90 percent of the boarding
passengers. The space should accommodate space for airline processing and information, passenger queues, seating for enplaning
passengers, although all need not be seated, and an exitway for
deplaning passengers.
Processing queues should not extend into the corridor to the
extent that circulation is impaired. Lounge depths of 25 to 30 ft are
considered reasonable for holding boarding passengers. Space for a
departure lounge is proportioned on the basis of from 10 to 15 ft2 per
boarding passenger. Therefore, if a departure lounge is to accommodate 100 boarding passengers for a flight, its area should range from
1000 to 1500 ft2. To a greater and greater extent common departure
lounge areas are being utilized and these are sized based upon the
total peak hour boarding passengers for the gates being served by
the common lounge. Since it is likely that boarding for these aircraft
will occur at different times in the peak hour, the total space required
for separate lounges may be reduced by 20 to 30 percent for common
lounges.
The corridor provided for deplaning passengers should be about
10 ft in width. The airline processing area should provide for at least
two positions for narrow-bodied aircraft and up to four positions for
wide-bodied aircraft to minimize queue lengths extending into the corridor. Processing rates range from one to two passengers per minute at
these positions and peak arrival rates range from 10 to 15 percent of the
boarding passengers. Therefore, queue depths of about 10 ft are reasonable values for preliminary design for individual departure lounges. For
common lounges, the position of the processing area should be such as
not to interfere with the circulation of passengers in the vicinity of the
entrances and exits from the lounge. Typically these positions are
located in the center of a satellite facility or at the end of the corridor
409
410
Airport Design
Lounge
Circulation
Circulation
Ticket
lift
Deplaning
corridor
Baggage check in
Seating group
Passenger
queueing
Passenger
queueing
Lounge exit
Passenger
deplaning
Enplaning queueing
Concourse
FIGURE 10-13 Departure lounge layout (Federal Aviation Administration [50]).
in a pier facility. Figure 10-13 shows the layout for a departure lounge
seating about 70 passengers.
Corridors
Corridors provide circulation for passenger and visitor between
departure lounges and between departure lounges and the central
terminal areas. These should be designed to accommodate physically handicapped persons during the peak periods of high-density
flow. Studies have shown that a typical 20-ft-wide corridor will have
a capacity ranging from 330 to over 600 persons per minute. For
planning purposes, corridor widths should be sized on the basis of
about 16.5 passengers per foot of width per minute. The corridor
width should be the width required at the most restrictive points,
that is, the minimum free-flow width in the vicinity of restaurant
entrances, phone booth clusters, or departure lounge check-in points.
This standard is based upon a width of 2.5 ft per person and a depth
separation of 6 ft between people. The corridor width is adversely
impacted by the peaking of deplaning passengers in platoons but
the deceased depth separations compensate for the decreased walking rates in these circumstances.
Further guidance on corridor width design is contained in the
literature [12, 41, 43, 50].
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Baggage Claim Facilities
The baggage claim lobby should be located so checked baggage may
be returned to terminating passengers in reasonable proximity to the
terminal deplaning curb. At low activity airports, checked baggage
may be placed on a shelf for passenger claiming. More active airports
have installed mechanical delivery and display equipment similar to
that depicted in Fig. 10-14. The number of claim devices required is
determined by the number and type of aircraft that will arrive during
the peak hour, the time distribution of these arrivals, the number of
terminating passengers, the amount of baggage checked on these
flights, and the mechanism used to transport baggage from aircraft to
L
L
INPUT
INPUT
WALL
WALL
DISPLAY
W
W
DISPLAY
FLATBED – DIRECT FEED
FLATBED – DIRECT FEED
SHAPE
L
FT (M)
W
FT (M)
CLAIM FRONTAGE BAG
STORAGE
FT (M)
65 (20)
5 (1.5)
65 (20)
78
85 (26)
45 (13.7)
180 (55)
216
85 (26)
65 (20)
220 (67)
264
50 (15)
45 (13.7)
190 (58)
228
FLOOR LEVEL A
FLOOR LEVEL B
L
CIRCULAR
REMOTE FEED SLOPING BED
OVAL
REMOTE FEED SLOPING BED
DIAMETER CLAIM FRONTAGE BAG
FT (M)
STORAGE
FT (M)
L
FT (M)
W
FT (M)
CLAIM FRONTAGE BAG
STORAGE
FT (M)
20 (6)
63 (19)
94
36 (11)
20 (6)
95 (29)
170
25 (7.5)
78 (24)
132
52 (16)
20 (6)
128 (39)
247
30 (9)
94 (29)
169
68 (21)
18 (5.5)
156 (48)
318
THEORETICAL BAG STORAGE – PRACTICAL BAG STORAGE CAPABILITY IS 1/3 LESS
FIGURE 10-14 Mechanized baggage claim devices commonly used at airports
(Federal Aviation Administration [43]).
411
412
Airport Design
the claim area. In the ideal situation, a baggage claim device should not
be shared between flight arrivals at the same time as this leads to considerable congestion in the vicinity of the device and passenger confusion.
Greater utilization of the devices is obtained when airlines time the sharing of claim devices for separate flights. Techniques similar to those used
to construct ramp charts are useful in scheduling baggage claim devices
and for determining the level of congestion in the baggage claim area.
At the present time, except in the most unusual situations, passenger delays in the baggage claim area can be significant due principally to the fact that passengers can travel from aircraft to claim areas
much faster than baggage conveyance systems can transport the baggage from aircraft to claim areas. It is therefore essential that claim
lobbies be designed to accommodate waiting passengers adequately
and provide for rapid claiming of baggage once the baggage is transferred to the claim device. Estimating procedures have been provided
by the FAA for sizing claiming devices based upon the equivalent
peak 20-min aircraft arrivals. Charts for this purpose are provided in
Figs. 10-15 and 10-16. It should be observed that these charts are
Equivalent aircraft arrivals in peak 20 min
50
45
40
35
30
25
20
15
10
5
(00) Linear units of claiming frontage*
15
10
5
0
ft
4.5
3.0
1.5
0
m
100
90
80
70
60
50
40
30
20
Percent of arriving passengers terminating locally
*Based on 1.3 average
bags per passenger
Equivalent aircraft
(A)
(B)
(C)
Peak arrivals, Equivalent air- Equivalent air20 min
craft factor
craft in peak
Seats
Up to 80
81 to 110
111 to 160
161 to 210
211 to 280
281 to 420
421 to 500
.6
1.0
1.4
1.9
2.4
3.5
4.6
(C) Product of columns A & B
FIGURE 10-15 Estimating nomograph for baggage claim linear claim footage
requirements (Federal Aviation Administration [43]).
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
20
18
Claiming area, 000 ft2
16
A
B
C
D
E
14
12
10
8
6
4
2
0
100
200
300
Linear feet of claim display
400
500
Areas for optimum configurations of
A Round – sloping bed/remote feed
Tee – flat bed/direct feed
B Tee and u-shape alternating @ 75'
(flat bed/direct feed)
C Oval – flat bed/direct feed
Oval – sloping bed/remote feed
D Tee and u-shape alternating @ 60'
(flat bed/direct feed)
E – shape flat bed/direct feed
FIGURE 10-16 Estimating chart for total area of baggage claim facilities
(Federal Aviation Administration [43]).
based upon checked baggage at the rate of 1.3 bags per person and
adjustments may be required as baggage exceeds this rate.
In preliminary planning studies, great care should be exercised in
using the above guidelines. Particular attention should be given to
the space provided around a claim device and it is specifically recommended that a clear space of from 13 to 15 ft be provided adjacent
to the device for active and waiting claim, as well as claim area
circulation. In some instances baggage lobbies have been designed
with adequate waiting areas and subsequently other facilities have
been moved into these areas, considerably diminishing mobility. It
is recommended that an additional 15 to 35 ft of circulation space
be provided within the deplaning facility to allow for circulation
between the claim devices, rental car positions, and deplaning
curbs. If ground transportation facilities are located in these areas,
413
414
Airport Design
they should be physically positioned so as not to restrict passenger
flow to and from the claim area.
Intraairport Transportation Systems
The use of automated ground transportation systems within the terminal complex at airports is increasing as airports become larger and both
the distance and time for passengers to travel through airports have
become excessive. In most cases automated ground transportation also
provides a clear delineation between the airside and landside functions
of an airport and aids in the location of security processing facilities.
Moving walkways and automated people mover (APM) systems have
become important features in many large terminals.
An Automated People Mover (APM) is an advanced transportation system in which automated driverless vehicles operate on fixed
guideways in exclusive rights-of-way. They differ from other forms
of transit in that they operate without drivers or station attendants.
These systems have been developed and implemented in various
sizes and configurations since the early 1970s and today there are
over 40 systems operating at airports worldwide.
Most of the early APM systems were implemented to facilitate passenger movement within a terminal or between the central terminal and
a satellite building. Figure 10-17 shows an APM vehicle that operates in
an underground tunnel that links the central terminal with a mid-field
satellite terminal at the Greater Pittsburgh International Airport. More
recently, APM systems have been designed to connect airport terminals
FIGURE 10-17 Automated People Mover (APM) Vehicle at the Greater
Pittsburgh International Airport.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
and link terminals with landside facilities such as parking, car rental
services, regional transportation services, hotels, and other related
employment and activity centers. Guidance on the planning of such
facilities is contained in recent literature [20, 46, 59].
International Facilities
Airports with international operations require space for the inspection
of passengers, crew, baggage, aircraft, and cargo. The area required for
customs, immigration, agriculture, and public health services may be
in a separate facility or in the terminal building itself. These facilities
should be designed so that passenger flow between the aircraft and the
initial processing station is unimpeded and as short as possible, there
is no possibility of contact with domestic passengers or any unauthorized personnel until processing is complete, there is no possible way
for an international arrival to bypass processing, and there is a segregated area for in-transit international passengers.
The size of this facility is based on the projection of hourly passengers requiring processing. It is recommended that the appropriate officials and agencies be contacted during the preliminary deign phase to
determine specific design requirements. Some guidance on the processing rates and sizing of these facilities is found in the literature [43, 58].
Other Areas
Most terminals are developed to accommodate several other activities and the space needs should be determined for each airport based
upon local requirements. These activities are identified below.
Airline Activities
The following airline activities may exist at all or some terminal facilities and should be discussed with the airlines which plan on utilizing the facility.
1. Outbound baggage makeup and inbound baggage and conveyance system
2. Cabin services and aircraft maintenance
3. Flight operations and crew ready rooms
4. Storage areas for valuable or outsized baggage
5. Air freight pickup and delivery
6. Passenger reservations and VIP waiting areas
7. Administrative offices
8. Ramp vehicle and cart parking and maintenance
Passenger Amenities
The factors which influence the extent of passenger amenities include
the passenger volume, community size, the location and extent of
415
416
Airport Design
off-airport services, interests and abilities of potential concessionaires, and rental rates. These generally include
1. Food and beverage services, and newsstands
2. A variety of stores and services
3. Counters for car rental and flight insurance companies
4. Public lockers and public and courtesy telephones
5. Amusement arcades and vending machines
6. Public restrooms
Airport Operations and Services
These facilities and services are normal to most public buildings and
include the following:
1. Offices for airport management and staff functions including
police, medical and first aid, and building maintenance
2. Building mechanical systems such as heating, ventilation,
and air conditioning
3. Communication facilities
4. Electrical equipment
5. Government offices for air traffic control, weather reporting,
public health and immigration, and customs
6. Conference and press facilities
Overall Space Requirements
Guidelines have been presented above for the approximate space
requirements for the various components in passenger terminal facilities. Once the facilities have been estimated one might compare the
space requirements to the approximations given in Table 10-2. The
values in this table present overall space requirements which should
provide a reasonable level of service and a tolerable occupancy level
for the various facilities indicated.
Concept Development
In this phase of the process, the blocks of spaces determined in space
programming are allocated in a general way to the terminal complex.
There are a number of ways in which the facilities of the passenger
terminal system are physically arranged and in which the various
passenger processing activities are performed. Centralized passenger
processing means all the facilities of the system are housed in one
building and used for processing all passengers using the building.
Centralized processing facilities offer economies of scale in that many
of the common facilities may be used to service a large number of
aircraft gate positions. Decentralized processing, on the other hand,
means the passenger facilities are arranged in smaller modular units
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Component
Space Required in 1000 ft2 or
100 m2 per 100 Typical Peak
Hour Passengers
Ticket lobby
1.0
Baggage claim
1.0
Departure lounge
2.0
Waiting rooms
1.5
Immigration
1.0
Customs
3.0
Amenities
2.0
Airline operations
5.0
Total gross area
Domestic
25.0
International
30.0
TABLE 10-2 Typical Terminal Building Space Requirements
and repeated in one or more buildings. Each unit is arranged around
one or more aircraft gate positions and serves the passengers using
those gate positions. There are four basic horizontal distribution concepts, as well as many variations or hybrids which include combinations of these basic concepts. Each can be used with varying degrees
of centralization. These concepts are discussed below.
Horizontal Distribution Concepts
The following terminal concepts should be considered in the development of the terminal area plan. Sketches of the various concepts are shown
in Fig. 10-18. Many airports have combined one or more terminal types.
Pier or Finger Concept
The pier concept has an interface with aircraft along piers extending from
the main terminal area. Aircraft are usually arranged around the axis of
the pier in a parallel or nose-in parking alignment. Each pier has a row of
aircraft gate positions on both sides, with a passenger concourse along the
axis which serves as the departure lounge and circulation space for both
enplaning and deplaning passengers. This concept usually allows for the
expansion of the pier to provide additional aircraft parking positions
without the expansion of the central passenger and baggage processing
facility. Access to the terminal area is at the base of the connector or the
pier. If two or more piers are employed, the spacing between the two piers
must provide for maneuvering of aircraft on one or two apron taxilanes.
When each pier serves a large number of gates, and the probability exists
that two or more aircraft may frequently be taxiing between two piers and
417
Airport Design
Curb
Access interface
Processing
Flight interface
Curb
Access interface
Processing
Apron
Flight interface
(d)
Curb
Apron
Access interface
(a)
Curb
Processing
Access interface
Processing
Flight interface
418
Apron
Flight
interface
Apron
(b)
(c)
FIGURE 10-18 Horizontal distribution concepts for passenger terminals:
(a) linear, (b) pier, (c) satellite, (d) transporter.
will be in conflict with one another, then two taxilanes are advisable. Also,
access from this taxiway system by two or more aircraft may require two
apron edge taxiways to avoid delays.
The chief advantage of this concept is its ability to be expanded in
incremental steps as aircraft or passenger demand warrant. It is also relatively economical in terms of capital and operating cost. Its chief disadvantages are its relatively long walking distance from curb front to aircraft
and the lack of a direct curb front relationship to aircraft gate positions.
Satellite Concept
The satellite concept consists of a building, surrounded by aircraft, which
is separated from the terminal and is usually reached by means of a surface, underground, or above ground connector. The aircraft are normally
parked in radial or parallel positions around the satellite. It often affords
the opportunity for simple maneuvering and taxiing patterns for aircraft
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
but requires more apron area than other concepts. It can have common
or separate departure lounges. Since enplaning and deplaning from the
aircraft is accomplished from a common and often remote area, mechanical systems may be employed to transport passengers and baggage
between the terminal and satellite.
The main advantages of this concept lie in its adaptability to common departure lounge and check-in functions and the ease of aircraft
maneuverability around the satellite structure. However, construction cost is relatively high due to the need to provide connecting concourses to the satellite. It lacks flexibility for expansion and passenger
walking distances are relatively long.
Linear, Frontal or Gate Arrivals Concept
The simple linear terminal consists of a common waiting and ticketing
area with exits leading to the aircraft parking apron. It is adaptable to
airports with low airline activity which will usually have an apron providing close-in parking for three to six commercial passenger aircraft.
The layout of the simple terminal should take into account the possibility of pier, satellite, or linear additions for terminal expansion. In the
gate arrivals or frontal concept, aircraft are parked along the face of the
terminal building. Concourses connect the various terminal functions
with the aircraft gate positions. This concept offers ease of access and
relatively short walking distances if passengers are delivered to a point
near gate departure by vehicular circulation systems. Expansion may
be accomplished by linear extension of an existing structure or by
developing two or more terminal units with connectors.
Both of these concepts provide direct access from curb front to
aircraft gate positions and afford a high degree of flexibility for expansion. It does not provide convenient opportunities for the use of common facilities and, as this concept is expanded into separate buildings, it may lead to high operating costs.
Transporter, Open Apron or Mobile Conveyance Concept
Aircraft and aircraft servicing functions in the transporter concept are
remotely located from the terminal. The connection to the terminal is
provided by vehicular transport for enplaning and deplaning passengers. The characteristics of the transporter concept include flexibility in
providing additional aircraft parking positions to accommodate
increases in schedules or aircraft size, the capability to maneuver an
aircraft in and out of a parking position under its own power, the separation of aircraft servicing activities from the terminal, and reduced
walking distances for the passenger.
Concept Combinations and Variations
Combinations of concepts and variations are a result of changing conditions experienced from the initial conception of the airport throughout its life span. An airport may have many types of passenger activity,
varying from originating and terminating passengers using the full
range of terminal services to passengers using limited services on
419
420
Airport Design
commuter or connecting flights. Each requires a concept that differs
considerably from the other. In time, the proportion of traffic handled
by flights may change, necessitating modification or expansion of the
facilities. Growth of aircraft size or a new combination of aircraft types
servicing the same airport will affect the type of concept. In the same
way, physical limitations of the site may cause a pure conceptual form
to be modified by additions or combinations of other concepts.
Combined concepts acquire certain of the advantages and disadvantages of each basic concept. A combination of concept types can be
advantageous where more costly modifications would be necessary to
maintain the original concept. For example, an airline might be suitably accommodated within an existing transporter concept terminal
while an addition is needed for a commuter operation with rapid turnovers which would be best served by a linear concept extension. In this
situation, combined concepts would be desirable. The appearance of
concept variations and combinations in a total apron terminal plan
may reflect an evolving situation in which altering needs or growth
have dictated the use of different concepts. Illustrations of the generation of various horizontal distribution concepts in the concept development phase of Geneva Intercontinental Airport are shown in Fig. 10-19.
Applications of several of the concepts to existing airports are shown in
Fig. 10-20a through 10-20c.
FIGURE 10-19 Conceptual designs for Geneva Intercontinental Airport (Reynolds,
Smith and Hills [25]).
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
FIGURE 10-20A Linear, satellite and pier concepts—O’Hare International Airport.
FIGURE 10-20B
Airport.
Pier and satellite concepts—Cleveland Hopkins International
421
422
Airport Design
FIGURE 10-20C
Airport.
Satellite airside/landside concept—Tampa International
Figure 10-20a shows the terminal area layout at O’Hare International Airport which shows the linear, satellite and pier concepts.
Concourse B is a linear concept, concourse C is a satellite concept
connected to the main terminal building by an underground
moving sidewalk, and concourses E, F, G, H, K, and L are pier concepts. Figure 10-20b shows the terminal area layout at Cleveland
Hopkins International Airport which consists of pier and satellite
concepts. Figure 10-20c shows the terminal area layout at Tampa
International Airport which shows five airside satellites connected
to the landside building by automated transit on above ground fixed
guideways.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Vertical Distribution Concepts
The basis for distributing the primary processing activities in a
passenger terminal among several levels is mainly to separate
the flow of arriving and departing passengers. The decision concerning the number of levels a terminal facility should have
depends primarily on the volume of passengers and the availability of land for expansion in the immediate vicinity. It may
also be influenced by the type of traffic, for example, domestic,
international, or commuter passengers being processed, by the
terminal area master plan, and by the horizontal processing concept chosen.
With a single level system all processing of passengers and
baggage occurs at the level of the apron. Separation between arriving and departing passenger flows is achieved horizontally. Amenities and administrative functions may occur on a second level.
With this system, stairs are normally used to load passengers onto
aircraft. This system is quite economical and is suitable for relatively low passenger volumes. The single level terminal is shown
in Fig. 10-21a.
Curb
Terminal
Apron
(a)
Curb
Apron
Terminal
(b)
Curb
Apron
Terminal
Departing passenger flow
(c)
Arriving passenger flow
FIGURE 10-21 Vertical distribution concepts: (a) single level, (b) second level
loading, (c) two-level system (Federal Aviation Administration [50]).
423
424
Airport Design
Two level passenger terminal systems may be designed in a number of different ways. In one type, shown in Fig. 10-21b, the two levels are used to separate the passenger processing area and the baggage handling areas. Thus, processing activities including baggage
claim occur on the upper level, while airline operations and baggage
handling activities occur at the lower apron level. The advantage of
raising the passenger handling level is that it becomes compatible
with aircraft doorsill heights, allowing convenient interface with the
aircraft. Vehicular access occurs on the upper level to facilitate the
interface with the processing system.
Another articulation of the two-level system separates the arriving and departing passenger streams. In this case departing passenger processing activities occur on the upper level and arriving passenger processing including baggage claim occurs at the apron level.
Airline operations and baggage handling also occur at the lower
level. Vehicular access and parking occur at both levels, one for arrivals and one for departures, and parking can be surface or structural.
An example of this design is shown in Fig. 10-21c.
Variations in these basic designs may occur when traffic volumes or the type of traffic so require. For example, for international
airport terminals, a third level may be needed for international
passengers. Also, at large airports where intraairport transportation systems operate, a special level may be needed to provide for
these systems. Figure 10-22A shows a multilevel system with structural parking, intraairport transportation, and underground mass
transit access. Figure 10-22B shows a multilevel system with integrated structural parking. In this variation more direct access to the
processing component is attained by providing parking above the
processing facility.
Based upon an examination of a large number of airports, it is
possible to identify those concepts which are candidates for further
consideration. Using the level of annual enplanements and the function nature of the airport, as defined by the relative proportions of
originating, terminating, through, or connecting passengers, Fig. 10-23
offers some guidance to the airport planner for the initial identification of appropriate horizontal and vertical distribution concepts. It
should be noted, however, that in many instances the constraints of
existing terminal facilities, land availability, and the ground access
system may restrict the options which are viable alternatives for terminal expansion.
Prior to proceeding with the planning of the airport terminal system, an evaluation of the concepts which have evolved in the conceptual development phase of the project is undertaken, to identify those
alternatives which should be brought into the schematic design and
design development phase of the project. To do this an overall rating
of the various concepts relative to the design criteria is performed.
Mezzanine concessions
Intraairport transport
Departures
Roadway
Arrivals-airline operations
Utilities
Underground mass transit
Passenger flow
Baggage flow
FIGURE 10-22A
Multilevel passenger processing system—structural parking adjacent to terminal (Hamburg Airport Authority).
Motel
Mechanical
ATO
Outbound
425
FIGURE 10-22B
Inbound
Ticketing
Bag claim
Offices
Mechanical equipment
Multilevel passenger processing system—structural parking above processing area (Reynolds, Smith and Hills).
Airport Design
Aircraft level boarding
Apron level boarding
Multi level connector
Single level connector
Multi level terminal
Multi level curb
Single level curb
Transporter
Physical aspects
of concepts
Feeder under 25,000
X
X
X
X
Secondary 25,000 to 75,000
X
X
X
X
75,000 to 200,000
X
X
X
X
X
200,000 to 500,000
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Primary over 75% pax O/D
500,000 to 1,000,000
Over 25% pax transfer
500,000 to 1,000,000
Over 75% pax O/D
1,000,000 to 3,000,000
Over 25% pax transfer
1,000,000 to 3,000,000
Over 75% pax O/D over
3,000,000
Over 25% pax transfer
over 3,000,000
Pier
Airport size by enplaned
pax/year
Linear
Satellite
Concepts
applicable
Single level terminal
426
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
FIGURE 10-23 Applicable concepts for airport design (Federal Aviation
Administration [50]).
The concept evaluation rating factors used for Geneva airport are
listed in Table 10-3.
Schematic Design
The schematic design process translates the concept development
and overall space requirements into drawings which show the general size, location, and shape of the various elements in the terminal
plan. Functional relationships between the components are established and evaluated. The adequacy of the overall space program is
evaluated by airport users relative to their specific needs. This phase
of the process specifically examines passenger and baggage flow
routes through the system and seeks to examine the adequacy of the
facility from the point of view of flow levels and flow conflicts.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Passenger convenience:
Walking distance from curb to aircraft
Walking distance for transfer passengers
Walking distance from parking to aircraft
Ease of passenger orientation
Ease of passenger processing
Operational effectiveness:
Efficient taxing routes
Ground flow coordination of vehicles and aircraft
Apron area maneuverability
Apron adaptation to future aircraft
Vehicular access flows
Direct routes to ancillary facilities
Expansion adaptability:
Ancillary facilities, flexible land use
Staging adaptability
Visual character of increments
Gross terminal expandability
Expandability of terminal elements
Economic effectiveness:
Capital cost
Maintenance and operating costs
Ratio of revenue- to non-revenue-producing areas
Source: Reynolds, Smith and Hills [25].
TABLE 10-3 Conceptual Development Rating Factors for
Evaluation of Terminal Planning Concepts
Modeling techniques are usually employed in this phase of the process to identify passenger processing, travel, and delay times, and the
generation of lines at processing facilities. The main purpose for analyzing passenger and baggage handling systems is the determination of
the extent and size of the facilities needed to provide a desired level of
convenience to the passenger at reasonable cost. In this analysis alternative layouts can be studied to determine which is the most desirable.
Analysis Methods
A number of systems analysis techniques have proven to be useful
for the analysis of facilities for passengers and baggage. These include
network models, queuing models, and simulation models.
Network Models
These models are particularly useful for representing and analyzing
the interrelationships between the various components of a passenger
427
428
Airport Design
or baggage processing system. For example, passenger processing
can be represented as a network with the nodes representing service
facilities and the links representing the travel paths and passenger
splits. This type of representation allows estimation of delays to the
passenger at various locations within the terminal.
An example of a network that has been applied to the evaluation
of arriving passenger delay is the critical path model (CPM) [47].
CPM is used to coordinate the various activities that take place in the
system for handling both passengers and baggage. Nodes that represent critical activities, that is, those that take the greatest amount of
time, are easily identified and can be analyzed in more detail to determine their effect on the overall performance of the system.
The analysis of the service time and waiting time at each processor in a network model can be obtained through either analytical
queuing models or simulation.
Analytical Queuing Models
Queuing theory permits the estimation of delays and queue lengths
for service facilities under specified levels of demand. The application of queuing theory yields useful estimates of processing and delay
times from which the required sizes of facilities and operating costs
may be derived.
Virtually all of the components of the passenger handling system
can be modeled as service facilities using queuing models. The diagram in Fig. 10-24 and Example Problem 10-10 showed an example of
the application of a deterministic queuing model to the operation of a
runway system to determine aircraft delay. A similar type of analysis
can be applied to the analysis of passenger processing systems. It is
possible to evaluate the impact of adding ticket agents on delays to
passengers and on the size of the queues. With this information it is
possible to evaluate the feasibility of alternative operating strategies
for the ticketing facility.
Diagrams similar to this may be constructed for each of the processors for the passenger and baggage handling system and yield satisfactory results when the demand rate exceeds the service rate.
For the analysis of component delay and queue length when the
average demand rate over some period of time is less than the average service rate, queuing theory is used to generate mathematical
functions representative of the arrival and service performance of the
system. To specify the mathematical formulation of this problem, it is
necessary to define the arrival distribution, the service distribution,
the number and use of the servers, and the service discipline. Many
of the components which service passengers in the airport terminal
exhibit a random or Poisson arrival process. The service characteristics are usually exponential, constant, or some general distribution
defined by average service times and the variance of average service
time. In most cases, there is more than one channel for the performance
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
of passenger service, and the queuing mechanism is based on first
come, first served basis. Extensive research has been carried out in
recent years to determine mathematical formulations which adequately represent the processing system [2, 10, 14, 19, 21, 53, 56].
Because of the variability associated with passenger behavior at an
airport, it is virtually impossible to obtain precise mathematical formulations for delay at processors. However, reasonable estimates of
delay and corresponding queue lengths are possible using simple
formulations.
One such formulation [17, 35, 52, 56] is that of a multiple station
queuing system with a Poisson arrival distribution and a service time
distribution which is characterized by the average service time and
the variance of the average service time as shown in Eq. (10-1).
⎛ σ 2 + t2 ⎞
Ws = ⎜
⎝ 2t 2 ⎟⎠
λ k t k +1
n= k − 1
(k − 1)!(k − λt)
2
∑
[( λt )n /n!] + ( λt )k /[( k − 1)!( k − λt )]
(10-1)
n= 0
where Ws = average delay per person
λ = average demand rate
t = average service time for a processor, the reciprocal of the
average service rate of a processor, µ
σ = standard deviation of the average service time of a
processor
k = number of processors
n = counter in the equation
This equation is valid when the average demand rate on the system of processors λ is less than to total service rate of the processors,
kµ; that is, the ratio of the average demand rate to the total service
rate ρ is less than 1.
When the number of processors k is equal to 1, this equation
reduces to
σ 2 + t2
λ
(10-2)
Ws =
2 µ (µ − λ )
2
t
or since ρ is equal to λ/kμ
σ 2 + t2
ρ
Ws =
t 2 2 µ(1 − ρ)
(10-3)
For a single server system which exhibits a Poisson arrival distribution
and an exponential service time distribution, Eq. (10-1) reduces to
Ws =
λ
µ (µ − λ )
(10-4)
Ws =
ρ
µ(1 − ρ)
(10-5)
or
429
430
Airport Design
For a single server system which exhibits a Poisson arrival distribution and a constant service time distribution, Eq. (10-1) reduces to
Ws =
λ
2 μ (μ − λ )
(10-6)
Ws =
ρ
2 μ(1 − ρ)
(10-7)
or
When demand is less than capacity, the following expression gives
the average line length N over the period being analyzed and consists
of those in service and those waiting for service at a processor.
⎛
1⎞
N = ⎜Ws + ⎟ λ
μ⎠
⎝
(10-8)
When ρ > 1 there is statistical delay plus excess delay which is
defined by a deterministic model. For design purposes it is sufficient
to estimate delays in such a system in which the statistical delay Ws is
computed from the appropriate equation above with ρ = 0.90 and the
excess delay We is added to this from the equation below to compute
total processor delay. The rationale for computing the statistical delay
with ρ = 0.9 is that in reality as demand approached capacity the
delay cannot become infinite as airline or airport operating practices
will limit delay by utilizing additional servers.
We =
T (λ − k μ )
2 kμ
(10-9)
where We = delay when the demand exceeds the service rate
T = time period during which the demand exceeds the service rate
λ = total demand on the system of processors
k = number of processors
μ = service rate of a processor
It is usually assumed that the time required to reduce the demand
to capacity T is about one-half of the time period being analyzed.
Typically when demand exceeds capacity, the operator of the facility
will increase the number of operating service facilities to alleviate the
growth in both waiting time and queue lengths. However, the extent
to which this is done is a function of airline operating policies and the
availability of additional manpower and physical facilities.
The average line length over the period analyzed N including
those in service and those waiting for service; when demand exceeds,
capacity can be estimated by the following equation.
⎛
1⎞
N = ⎜Ws + W e + ⎟ μ
μ⎠
⎝
(10-10)
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Estimates of the waiting times and queue lengths for multiple
service channels may be obtained by proportioning the demand
equally among processors with the same service characteristics and
utilizing single server models. Better estimates may be obtained
through the use of multiple channel queuing models whose mathematical formulation was given above. A representation of the passenger delay at baggage claim facilities is given by the relationship [52]
nT
(10-11)
− E(t1 )
n+1
where E(t2) = expected value of the time when the first piece of baggage arrives at the claim area
E(t1) = expected value of the time when passengers arrive at
the claim area
n = number of pieces of baggage to be claimed by each passenger
T = length of time from the arrival of the first bag until the
arrival of the last bag at the claim device
Wt = E(t2 ) +
Others have formulated models which show the buildup and dropoff of passengers and baggage in the claim area [19].
The use of a generalized probability density function called the
Erlang distribution is recommended as a mechanism for evaluating the
service characteristics of the various passenger component processors. By collecting a sample of data relative to a specific component,
the constant in the Erlang distribution function can be calculated.
This constant determines the particular functional relationships for
the server. It is possible that this type of distribution may better
describe the queuing characteristics of processors. This distribution
has been used successfully in passenger terminal modeling [15].
Great care must be exercised in the application of mathematical
models and the interpretation of the results. In most cases, the mathematical representation of the terminal system is best suited for the
comparison of alternatives and the identification of those components in the system requiring detailed analyses.
The specification of the service time distribution for use in queuing equations is a function of the distribution of service times demonstrated by the service facility. In general, those processors which
exhibit a requirement for small service times, for example, flow
through type facilities such as doors, security, and gates are probably
best represented by an exponential service time distribution. Those
facilities which require a finite service time at a processor such a ticketing, baggage check, seat selection, and rental car checkout, are probably best represented by either a general service time distribution,
which is characterized by the average service time and the standard
deviation of the average service time, or a constant service time
distribution.
431
432
Airport Design
In a network model, the average passenger processing time E(Tp)
is given by
E(Tp) = E(Tw) + E(Ts) + E(Td)
(10-12)
where E(Tw) = average passenger delay time throughout the system of
processors
E(Ts) = average passenger service time throughout the system
of processors
E(Td) = average passenger travel time through the network of
processors
Estimates for the observed range of service time for many of the passenger processing components at an airport are given in Table 10-4.
Example Problem 10-1 presents an illustration of the analysis of
the enplaning system at an airport using a network model and the
above queuing equations.
Example Problem 10-1 The terminal building layout for enplaning passengers at
an airport is given in Fig. 10-24.
Two airlines are servicing the airport, North American Airlines (NA) and
Western Pacific Airlines (WP). The enplaning passenger processing facilities and
their service rates are given in Table 10-5.
Ramp
Gate
Gate
Departure
Lounges
Outbound
Baggage
Seat
Selection
Airline
Offices
Security
Ticketing
Lobby
Entrances
Curb front
FIGURE 10-24 Layout of enplaning passenger processing system for
Example Problem 10-1.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Component Type
Service Rate per
Passenger, s
Standard
Deviation
Entrance and exit doors
Automated with baggage
2.0–25
0.5
Automated without baggage
1.0–1.5
0.75
Manual with baggage
3.0–5.0
1.0
Manual without baggage
1.5–3.0
0.75
Stairways
3.0–4.0
1.0
Escalators
1.0–3.0
1.0
Moving sidewalks
1.0–3.0
1.0
Apron doors
With stairs
4.0–8.0
2.0
Without stairs
3.0–7.0
1.5
Jetway
2.0–6.0
1.0
Manual with baggage
180–240
60
Manual without baggage
100–200
30
30–50
10
Ticketing and baggage
Baggage only
Information
20–40
10
160–220
30
90–180
40
Hand-check baggage
30–60
15
Automated
30–40
10
Single fights
25–60
20
Multiple fights
35–60
15
Automated with baggage
Automated without baggage
Security
Seat selection
Rental car
Check-in
Checkout
Automated check-in
120–240
60
180–300
90
60–90
20
Baggage claim
Manual
10–15
8
Automated carousel
5–10
5
Automated racetrack
5–10
5
Automated tee
6–12
5
Sources: Various airport studies.
TABLE 10-4 Observed Service Times for Passenger Processing Facilities
at Airports
433
434
Airport Design
Type
Airline
Number
Entrance doors
All
3
Regular ticketing
Average Service Time
per Passenger, s
15
NC
3
210
UA
3
180
Express check-in
UA
1
60
Security
All
2
30
Seat selection
NC
1
45
UA
1
30
Ramp gates
NC
1
20
UA
1
20
TABLE 10-5 Enplaning Passenger Service Processors for Example
Problem 10-1
Demand data collected at the airport indicate that 10 percent of the enplaning
passengers proceed directly from curb front to security, 20 percent of Western
Pacific Airlines enplaning passengers use the express check-in, there are 0.5
visitors per passenger during the peak hour, and 50 percent of these visitors
proceed beyond security.
The peak hour enplaning passenger demand on the design day is expected
to be 135 passengers, of which 53 percent use North American Airlines and
47 percent use Western Pacific Airlines. Typically the peak 30 min of the peak
hour has 57 percent of the peak hour demand. Assume average walking rates
are 1.5 ft/s. Airline operating practices limit the periods when demand exceeds
capacity to 15 min.
It is necessary to determine the average enplaning passenger delay and line
length at each processor, and the average passenger processing time during the
peak 30 min of the peak hour on the design day at this airport.
The link-and-node diagram in Fig. 10-25 shows the relationship between the
enplaning passenger processors at the airport, and includes the passenger split
between processors, the number of processors, the processing time per passenger,
and the distance between processor in feet.
Since the peak 30 min passenger arrival rate is 57 percent of the peak hour
arrival rate, the peak 30 min passenger demand into the enplaning passenger
system is 0.57(135) = 77 passengers. Since there are 0.5 visitors per passenger, the
peak 30 min visitor demand into the enplaning passenger system is 0.5(77) = 39
visitors. Combining these demand parameters with the passenger splits given
in Fig. 10-25, recognizing that only 50 percent of the visitors proceed beyond
security, the processor flow rates in the peak 30 min are given in Fig. 10-26. In
this figure the numbers above the lines connecting processors represent the passengers flowing into the processor and the numbers below these lines represent
the visitors flowing into each processor when the processor processes visitors.
Assuming that all processors may be modeled by single processor systems
in which the demand is split evenly between processors, the demand rate in
persons per minute, the service rate in persons per minute, and the ratio of the
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Entrance
Ticketing
Seat
Selection
Security
3
210
1
14 .0
4
1.0
3
15
0.3
10 4
2
0.10
153
8
0.0 3
9
3
180
Gates
1
45
1.0
20
1.0
20
1
20
1
30
1.0
20
1.0
20
1
20
53
0. 5
1
1.0
5
17
2
30
0.4
15 7
1.
16 0
6
48
0. 1
8
Departure
Lounge
1
60
FIGURE 10-25 Link–and-node diagram representing enplaning passenger processing
system for Example Problem 10-1.
Ticketing
37
26
9
37
Departure
Lounge
7
41
11
41
36
9
36
Gates
41
8
2
26
7
7
77
39
Seat
Selection
Security
2
Entrance
36
FIGURE 10-26 Link-and-node diagram representing passenger and visitor flows into
passenger processing facilities for Example Problem 10-1.
demand to capacity for each processor, the processor utilization, is computed
as shown in Table 10-6.
The departure lounges are accumulating processors and are analyzed differently than the queuing processors. Also note that the North American regular ticketing position and the North American seat selection components have a demand
which exceeds capacity since the processor utilization is greater than 1.
Based upon an examination airport processor it was found that those processors which are essentially flow-through processors (such as entrance doors,
security and ramp gates) behave as Poisson arrivals and exponential service rate
queuing mechanisms, whereas those processors which require a discrete service
435
436
Airport Design
Processor
Demand Rate,
pers/min
Service Rate
pers/min
Processor
Utilization
Entrance doors
1.29
4.00
0.32
North American
0.41
0.29
1.41
Western Pacific
0.29
0.33
0.88
0.23
1.00
0.23
1.62
2.00
0.81
North American
1.37
1.33
1.03
Western Pacific
1.20
2.00
0.60
North American
1.37
3.00
0.46
Western Pacific
1.20
3.00
0.40
Regular ticketing
Express check-in
North American
Security
Seat selection
Ramp gates
TABLE 10-6 Service Processor Characteristics for Example Problem 10-1
function (such as regular ticketing, express check-in, and seat selection) behave
as Poisson arrival and constant service rate queuing mechanisms.
Therefore, for the entrance doors, which are Poisson arrivals and exponential
services, the average passenger delay is from Eq. (10-4),
Ws =
1 . 29
= 0 . 12 min
4 . 00(4 . 00 − 1 . 29)
and from Eq. (10-8) the average line length is
⎛
1 ⎞
1 . 29 = 0 . 48 person
N = ⎜ 0 . 12 +
4 . 00⎟⎠
⎝
For the North American regular ticket counters, which exhibit Poisson arrivals
and constant services, since the demand rate is greater than the capacity, we have
from Eq. (10-7) with ρ = 0.9
0.9
Ws =
= 15 . 52 min
2(0 . 29)(1 − 0 . 9)
and from Eq. (10-9)
We =
15(0 . 41 − 0 . 29)
= 3 . 10 min
2(0 . 29)
Note that the value of k is equal to 1 because the demand was allocated equally
among each of the ticketing positions, and the excess delay period T is equal to
0.5(30) = 15 min.
Therefore, W = 15.52 + 3.10 = 18.62 min of average delay time per passenger.
The average line length is, from Eq. (10-10),
⎛
1 ⎞
0 . 29 = 6 . 40 passengers
N = ⎜18 . 62 +
0 . 29⎟⎠
⎝
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Delay Time
Processor
Statistical, min
Entrance doors
0.12
Service
Excess, min
Line Time,
min
Length,
pers
0.25
0.48
3.45
6.40
Regular ticketing
North American
15.52
3.10
Western Pacific
10.98
3.00
4.05
0.15
1.00
0.26
2.13
0.50
4.26
0.75
5.80
0.50
1.06
Express check-in
Western Pacific
Security
Seat selection
North American
3.38
Western Pacific
0.38
0.23
Ramp gates
North American
0.28
0.33
0.84
Western Pacific
0.22
0.33
0.66
TABLE 10-7 Average Passenger Delay Time, Service Time, and Processor Line
Lengths in Peak 30 Min for Example Problem 10-1
Computing the delays and queue lengths for each processor results in the
values shown in Table 10-7.
From this table it can be seen that considerable delay and line formation exist
at the both North American and the Western Pacific regular ticketing facilities,
the security check-point, and the North American seat selection facility.
From the passenger splits shown in Fig. 10-25 and the distances between
components, the expected values of the passenger delay time, the passenger
service time, and the travel time for the average airport passenger in the peak
30 min can be computed.
The expected values are then computed for the delay time, service time, and
walking time for the average airport passenger to find the average passenger
processing time from Eq. (10-11).
E(Td) = 1.0(0.12) + 0.48(15.52 + 3.10) + 0.34(10.98) + 0.08(0.15) + 1.0(2.13)
+ 0.53(3.38 + 0.28) + 0.47(0.38 + 0.22)
E(Td) = 17.2 min
E(Ts) = 1.0(0.25) + 0.48(3.45) + 0.34(3.00) + 0.08(1.00) + 1.0(0.5)
+ 0.53(0.75 + 0.33) + 0.47(0.50 + 0.33)
E(Ts) = 4.5 min
E(Dw) = 0.48(81 + 144) + 0.34(102 + 175) + 0.08(93 + 166) + 0.10(153)
+ 0.53(55) + 0.47(55)
E(Dw) = 293 ft
293
E(Tw ) =
= 3 . 3 min
1 . 5(60)
437
438
Airport Design
Time before
Scheduled
Departure,
min
Percentage of
Passengers at
Airport
Time before
Scheduled
Departure,
min
Percentage of
Passengers at
Airport
95
0
45
31
90
0
40
40
85
1
35
51
80
2
30
61
75
3
25
71
70
5
20
80
65
8
15
88
60
12
10
94
55
17
5
98
50
23
0
100
TABLE 10-8 Typical Arrival Distribution of Originating Passengers at the
Airport for Domestic Flights for Example Problem 10-1
The average passenger processing time for the average airport passenger
during the peak 30 min is then
E(Tp) = 17.2 + 4.5 + 3.3 = 25 min
Since departure lounges are only waiting areas, there is no queuing system
type delay in these facilities. Generally speaking, these facilities are designed
with an area requirement per passenger and visitor in the departure lounge. The
area required is based upon the number of passengers and visitors which would
be in the departure lounge at the moment the aircraft is allowed to be boarded.
Typically the square footage requirement is from 15 to 25 ft2 per person in the
departure lounge at that point.
Given a typical arrival distribution at the airport, such as that shown in Table 10-8,
it is assumed that the total number of passengers and visitors arriving at the airport
at the moment the flight is called for boarding is also the number in the departure
lounge at that point in time.
In this problem, let us assume that the flight is boarded 15 min before scheduled departure and the airline departure lounge requirements are 20 ft2 per
passenger.
Therefore, at this time 88 percent of the passengers and their visitors would
be in the departure lounge. For Western Pacific Airlines, this means that there are
0.88(0.47)(135) passengers and 0.88(0.47)(135)(0.5)(0.5) visitors in the departure
lounge at this point in time. This totals 56 passengers and 14 visitors. Therefore,
the departure lounge size requirements are 20(56 + 14) = 1400 ft2.
Simulation Models
These models become particularly useful when the analysis of the operation of the passenger handling system is to be performed at a relatively
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
detailed level or when it is desired to analyze the operation of the system for extended periods of time. They are useful for the analysis of the
whole system, as well as of parts of it [28, 34, 39]. When some important
inputs to analysis are unobtainable, such as possible future flight schedules, it is possible with the use of computer simulation to analyze the
operation of the system under randomly generated inputs.
Simulation is also particularly useful when analysis is to be repeated
for varying operating conditions in order to perform sensitivity studies. Computers allow such repeated analysis which would otherwise
be prohibitively expensive and very time consuming. Most computer
systems have standard simulation packages available which can be
adapted to many physical planning problems including airports.
It is important to note that computer simulation is not a substitute
for analysis when information on the system is lacking. In order to construct a simulation model nearly as much detailed information about
system operation is necessary as for other analytic techniques. The main
feature of simulation is the high speed at which computers can perform
lengthy calculations. In the analysis of systems operations computer
simulation should be used with caution and several runs made so that
the statistical reliability of the results may be determined.
Simulation techniques have been studied by the FAA [10, 21, 24]
and have been used in many studies to determine facility needs. An
outline of the flow of an enplaning passenger through the airport system which can be modeled by the FAA simulation model is given in
Fig. 10-27. In the schematic design phase of the planning project at
Fort Lauderdale-Hollywood International Airport, simulation was
used to determine the parking requirements at the airport and the
number of parking toll collection facilities needed at the exit [30]. The
inputs into the simulation was the airline flight schedule, the distribution of the total number of parkers relative to the flight schedule,
and the historical distribution of parking duration as obtained from
the analysis of parking ticket stubs. Alternative flight schedules were
used to generate the arrival distribution at the parking facility, and
the parking duration distribution, shown in Fig. 10-28, was used to
generate the random service times required by the arrivals. As a result
of the simulation, it was possible to determine the peaking characteristics of arrivals and departures at the parking garage, and the accumulation of vehicles within the parking facility.
The following steps are recommended in the design of a simulation model for application to airport terminal projects [50]:
1. Define the scope of the simulation in terms of the questions to
be answered, the components to be included, and the level of
detail required.
2. Specify the required output so that an interpretation of the
results will resolve the questions to be addressed.
439
440
Passenger generation
Arrival
distribution
prior to
flight time
Flight schedule
Airline
Gate
Depart
time
No. of pass.
No. of
transfer
pass.
No.
Time
Assign
Ticketing
and checking
Airline 1
Airline 2
Security
Concourse
1
Curbside N
Concourse
2
Taxi
Curbside 1
Curbside 2
Gates
Gate 1
Gate 2
Gate I
Gate I + 1
Gate I + 2
Gate J
A/C
Transfer
pass
Transfer
pass
Curbside N
Flight number
Transportation
mode
Ticket status
Gate number
Number of bags
DOM/INT
Landside
routing
Passenger
group size
Number of
well–wishers
FIGURE 10-27
Ground
transportation
Private vehicle
Curbside 1
Curbside 2
Bus/time
Station 1
Station 2
Station N
Self driven
Parking
lot
Rental car
Parking
lot
Gate L
Concourse
N
Airline N
Flow chart for enplaning passenger simulation model (Federal Aviation Administration [10]).
Transfer
pass
Gate M
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
20
18
16
14
Percent
12
10
March 1981
November 1980
8
6
4
2
0
1
2
3
6
12
48
120
504
Parking duration, hours
FIGURE 10-28 Parking duration at Fort Lauderdale-Hollywood International Airport
(Aviation Planning Associates, Inc. [30]).
3. Structure the model so that the abstract representation of the
components in the model and the events and interactions
between components are indicative of terminal performance.
4. Define the input data and its variability.
5. Once the model has been developed verify through testing
on actual systems.
6. Apply the model and modify the facility design in accordance
with the model results.
7. Review the findings and design relative to the degree of variability in the output and through reasonable checks.
Design Development
The final planning phase in terminal projects is called design development. In this phase the size and character of the project is fixed and
checked against the findings and recommendations in the prior
phases of the project. Acceptance of the project by the airport owner,
tenants, and airlines is the final product of this phase. Capital budgeting, operating, maintenance, and administrative costs over the lifetime of the project are determined and a revenue plan is adopted.
Agreements are made on rate and charge structures for the airlines,
concessionaires, and other tenants. The project moves on toward
441
442
Airport Design
implementation through the development of construction documents, bid letting and acceptance, and construction following this
phase of planning.
The Apron Gate System
The apron provides the connection between the terminal buildings
and the airfield. It includes aircraft parking areas, called ramps, and
aircraft circulation and taxiing areas for access to these ramps. On the
ramp, aircraft parking areas are designated as gates. The discussion
in this section is limited to the apron gate area for scheduled commercial aircraft operations. The size of the apron gate area depends
on four factors, namely, the number of aircraft gates, the size of the
gates, the maneuvering area required for aircraft at gates, and the
aircraft parking layout in the gate area. The layout of the apron area
is discussed in Chap. 6.
Number of Gates
As in the case with other airport facilities, the number of gates is determined in such a way that a predetermined hourly flow of aircraft can
be accommodated. Thus, the number of gates required depends on
the number of aircraft to be handled during the design hour and on
the amount of time each aircraft occupies a gate. The number of aircraft that need to be handled simultaneously is a function of the traffic volume at the airport. As mentioned earlier, it is customary to use
the estimated peak hour volume as the input for estimating the number of gates required at the airport. However, in order to achieve a
balanced airport design, this volume should not exceed the capacity
of the runways.
The amount of time an aircraft occupies a gate is referred to as the
gate occupancy time. It depends on the size of aircraft and on the type
of operation, that is, a through or turnaround flight. Aircraft parked
at a gate are there for passenger and baggage processing and for aircraft servicing and preparation for flight. Larger aircraft normally
occupy gates a longer time than small aircraft. This is because large
aircraft require more time for aircraft servicing, preflight planning,
and refueling. The type of operation also affects gate occupancy time
by affecting service requirements. Thus an aircraft on a through flight
may require little or no servicing and, consequently, the gate
occupancy time can be as low as 20 to 30 min. On the other hand, an
aircraft on a turnaround flight will require complete servicing, resulting in gate occupancy times ranging from 40 min to more than 1 h.
The table shown in Fig. 10-29 lists the activities that normally take
place during a turnaround stop, together with a typical time schedule
for these activities.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Time, min
0
5
10
15
20
25
Operations
Engine rundown
Position passengers’ bridges
Deplane passengers
Check log book
Off-load cargo
Bulk
Containers center
Forward
Service galley
Lavatory service
Water service
Cabin service
Fuel aircraft
Water injection service
Walk-around inspection
Load cargo
Containers forward
Center
Bulk
Check log book
Enplane passengers
Monitor engine start
Remove passengers’ bridges
Clear aircraft for departure
1.0
0.5
4.4
1.5
13.0
4.4
3.4
7.9
8.5
12.7
16.0
23.0
14.7
9.0
3.1
3.8
13.0
1.5
5.6
3.0
0.5
1.0
Critical time path
FIGURE 10-29 Typical time schedule of aircraft servicing activities at gate (Ralph M.
Parsons and Federal Aviation Administration [50]).
If simulation is used a design-day schedule is first forecast and,
then based upon the design-day schedule and the practices of the
airlines at the airport, a ramp chart based upon the design day is constructed to determine gate requirements.
The average daily gate utilization factor for all gates at an airport
usually varies between 0.5 and 0.8. This factor accounts for the fact
that it is unlikely that all of the gates available at a terminal building
will be used 100 percent of the time. This is caused by the fact that
aircraft maneuvering into and out of a gate often blocks other aircraft attempting to move into or out of their gates and by the fact that
aircraft schedules often lead to time gaps between the departure of
one aircraft and the arrival of another using the same gate. The gateuse strategy employed by the airlines at the airport also influences the
average gate utilization factor. At airports where gates are used
mutually by all airlines, a common gate-use strategy, the gate utilization factor typically varies between 0.6 and 0.8. At airports where
groups of gates are used exclusively by different airlines, an exclusive gate-use strategy, the utilization factor drops to about 0.5 or 0.6.
The determination of the number of gates needed at an airport
should be subjected to the analysis techniques given in Chap. 12 and
to the gate-use strategies adopted by the tenant airlines.
An illustration of the use of simulation to generate a design-day
schedule from which a ramp chart can be constructed to determine
design-day gate requirements in given in Example Problem 10-2.
443
444
Airport Design
Example Problem 10-2 The current schedules of airline flights at an airport on a
typical day in the peak month are given in Table 10-9. A forecast is made for this
airport which indicates that 10 additional flights will be added to the future-year
design-day schedule at this airport. It is necessary to perform a simulation for
the schedules of these additional flights.
It will be assumed in this problem that the flight schedule of the simulated
flights will follow the current day flight schedule distribution.
First it is necessary to obtain a probability distribution for both flight arrival
times and gate occupancy times. These are obtained by determining the frequency distribution of each time range for flight arrivals and gate occupancy
times and then integrating this frequency distribution to obtain the cumulative
probability distribution function.
For simplicity in this problem, the flight arrival time distribution is found by
grouping flight arrival times into 1-h increments of time and the gate occupancy
Time of
Airline
Flight Number
Arrival
AE
8/7
7:45 A.M.
9:30 A.M.
727
AE
353
10:30 A.M.
11:15 A.M.
727
AE
319/642
11:30 A.M.
1:00 P.M.
727
AE
421
12:00 P.M.
1:00 P.M.
727
AE
439
1:45 P.M.
2:30 P.M.
727
AE
889
1:45 P.M.
2:30 P.M.
727
AE
852
3:30 P.M.
4:00 P.M.
727
AE
422/660
3:45 P.M.
5:00 P.M.
727
AE
591/544
5:15 P.M.
6:15 P.M.
727
AE
310/390
6:00 P.M.
8:00 P.M.
727
AE
411/428
9:00 P.M.
10:15 P.M.
727
CL
64
7:15 A.M.
7:45 A.M.
737
CL
489
11:15 A.M.
11:45 A.M.
737
CL
41
11:30 A.M.
12:15 P.M.
737
CL
50
1:45 P.M.
2:15 P.M.
737
CL
936
1:45 P.M.
2:15 P.M.
737
CL
81
4:15 P.M.
5:00 P.M.
737
CL
493
8:30 P.M.
9:00 P.M.
737
RX
161
10:15 A.M.
10:45 A.M.
MD8
RX
321/844
4:45 P.M.
5:45 P.M.
MD8
TABLE 10-9
Departure
Aircraft
Current Airline Schedule on Typical Day in the Peak Month for
Example Problem 10-2
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
time distribution is found by grouping gate occupancy times into 15 min increments of time.
The flight schedule frequency distribution is then found by counting the
number of flights in each 1-h increment of time beginning with 6:00 A.M. and
ending with 11:59 P.M. The total number of flights arriving in the periods is
shown in Table 10-10.
The cumulative probability distribution function of flight arrival times is then
computed by finding the probability that a flight will arrive in a given time period
or later beginning with the earliest time period. These values are computed in Table
10-10 and plotted in Fig. 10-30.
By a similar technique, the gate occupancy durations of the flights are
grouped as shown in Table 10-11 and the cumulative probability function of
these gate occupancy times is plotted in Fig. 10-31.
To simulate a flight arrival and a gate occupancy time for a flight, a table of
random digits must be referenced. If this is done, two sets of random numbers,
one representing the flight arrival time and one representing the gate occupancy
Arriving in Period or Later
Time Period
From
To
Number of
Flights
Cumulative
Number
Cumulative
Percentage
6:00 A.M.
6:59 A.M.
0
20
1.00
7:00 A.M.
7:59 A.M.
2
20
1.00
8:00 A.M.
8:59 A.M.
0
18
0.90
9:00 A.M.
9:59 A.M.
0
18
0.90
10:00 A.M.
10:59 A.M.
2
18
0.90
11:00 A.M.
11:59 A.M.
3
16
0.80
12:00 P.M.
12:59 P.M.
1
13
0.65
1:00 P.M.
1:59 P.M.
4
12
0.60
2:00 P.M.
2:59 P.M.
0
8
0.40
3:00 P.M.
3:59 P.M.
2
8
0.40
4:00 P.M.
4:59 P.M.
2
6
0.30
5:00 P.M.
5:59 P.M.
1
4
0.20
6:00 P.M.
6:59 P.M.
1
3
0.15
7:00 P.M.
7:59 P.M.
0
2
0.10
8:00 P.M.
8:59 P.M.
1
2
0.10
9:00 P.M.
9:59 P.M.
1
1
0.05
10:00 P.M.
10:59 P.M.
0
0
0.00
11:00 P.M.
11:59 P.M.
0
0
0.00
TABLE 10-10
Aircraft Arrival Distribution for Example Problem 10-2
445
Airport Design
Probability of Arriving in Period or Later
446
1.00
0.92
0.80
0.60
0.54
0.40
0.20
0.00
6a
8
10
12p
2
4
6
8
10
12a
Time of Arrival
FIGURE 10-30 Flight arrival distribution for Example Problem 10-2.
time, for each of the 10 flights to be simulated are found and these are shown
in Table 10-12.
The first simulated flight has an arrival time random number of 0.92 and
a gate occupancy time random number of 0.70. Using the flight arrival time
Gate Occupancy
Time Period, Min
From
To
Duration Range or More
Number of
Flights
Cumulative
Number
Cumulative
Percentage
0
14
0
20
1.00
15
29
0
20
1.00
30
44
7
20
1.00
45
59
5
13
0.65
60
74
3
8
0.40
75
89
2
5
0.25
90
104
1
3
0.15
105
119
1
2
0.10
120
134
1
1
0.05
135
149
0
0
0.00
150
164
0
0
0.00
165
179
0
0
0.00
180
194
0
0
0.00
TABLE 10-11 Aircraft Gate Occupancy Time Distribution for Example
Problem 10-2
Probability of Parking for Duration or More
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
1.00
0.80
0.70
0.60
0.40
0.19
0.20
0.00
0
15
30
45
60
75
90
105
120
135
Gate Occupancy Time (minutes)
Flight gate occupancy duration for Example Problem 10-2.
FIGURE 10-31
random number of 0.92 with the cumulative probability function of flight arrival
times in Fig. 10-30, we find that the simulated arrival time of the first flight
is 7:45 A.M. Using the gate occupancy time random number of 0.70 with the
cumulative probability function of gate occupancy times in Fig. 10-31, we find
that the simulated gate occupancy time of the first flight is 45 min. Both of these
numbers are taken to the nearest 15 min time increment for simplicity. Therefore,
the first simulated flight has an arrival time of 7:45 A.M. and a flight departure
time of 8:30 A.M.
Aircraft Arrivals
Simulated
Flight
Random
Number
Arrival
Time
Gate Occupancy Time
Random
Number
Duration
Time
Departure
Time
1
0.92
7.45
0.70
45
8.30
2
0.88
10.15
0.80
45
11.00
3
0.54
1.15
0.19
90
2.45
4
0.18
5.30
0.62
45
4.15
5
0.82
10.45
0.43
60
11.45
6
0.87
10.15
0.86
30
10.45
7
0.75
11.15
0.46
60
12.15
8
0.28
4.15
0.69
45
5.00
9
0.59
1.00
0.87
30
1.30
10
0.60
1.00
0.93
30
1.30
TABLE 10-12
Gate Simulation Results for Example Problem 10-2
447
448
Airport Design
This process is continued for each simulated flight. For example, the third
simulated flight has an arrival time random number of 0.54 and a gate occupancy time random number of 0.19. Again, using the flight arrival time random
number of 0.54 with the cumulative probability function of flight arrival times
in Fig. 10-30, we find that the simulated arrival time of the third flight
is 1:15 P.M. Using the gate occupancy time random number of 0.19 with the
cumulative probability function of gate occupancy times in Fig. 10-31, we find
that the simulated gate occupancy time of the third flight is 90 min. Therefore,
the third simulated flight has an arrival time of 1:15 P.M. and a flight departure
time of 2:45 P.M.
The above simulation process is shown by the dashed lines in Figs. 10-30
and 10-31.
Assuming a simulation was also performed for the airline and the aircraft for
each flight, the results of the simulation are tabulated in Table 10-12. The new
flight schedule in the design year, with both the current flights and the simulated
flights, is shown in Table 10-13. In this table the simulated flights are each given
the flight number 9999 for reference purposes.
Ramp Charts
A ramp chart is a graphical representation of the gate occupancy by
aircraft throughout the day. Airlines and airports use ramp charts to
display the actual gate assignment of aircraft for the flight schedule at
the airport.
The ramp chart can also be used to determine the gate requirements
at an airport. When it is used for this purpose the ramp charts does not
display the actual assignment of aircraft to specific gates for the designday schedule but only indicates the assignment of aircraft to gates for
the determination of the number of gates required at the airport.
There are several factors which influence the gate requirements at
an airport. Obviously the flight schedule and the gate occupancy time
of aircraft are of paramount importance. However, the scheduling
and ramp operating practices of the airlines and the gate-use strategy
of the airlines are also important. The scheduling and ramp operating
practices give rise to the fact that a gate cannot be used 100 percent of
the time as discussed earlier. The gate-use strategy considers whether
the gates will be exclusive-use gates, shared-use gates or common
gates. Exclusive-use gates are gates which are reserved for the exclusive use of one airline. A shared gate is a gate which is shared by two
or three airlines. A common-use gate is a gate which is allocated by
the airport based upon the demand for gates and may be used by any
airline at the airport.
Gates are sized based upon the geometric properties of the
aircraft that will occupy the gates. Therefore, gates may be called
wide-bodied gates because they are sized to accommodate wide-bodied
aircraft. These gates may also be used by narrow-bodied aircraft.
Narrow-bodied gates are gates which can only be used by narrowbodied aircraft. Many airports also have commuter gates which are
sized to accommodate commuter aircraft.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Ref
No.
Airline
Flight
Number
1
AE
8/7
2
AE
Time of
Arrival
Departure
Aircraft
7:45 A.M.
9:30 A.M.
727
9999
10:15 A.M.
10:45 A.M.
727
3
AE
9999
10:15 A.M.
11:00 A.M.
727
4
AE
353
10:30 A.M.
11:15 A.M.
727
5
AE
9999
10:45 A.M.
11:45 A.M.
727
6
AE
319/642
11:30 A.M.
1:00 P.M.
727
7
AE
421
12:00 P.M.
1:00 P.M.
727
8
AE
9999
1:00 P.M.
1:30 P.M.
727
9
AE
9999
1:00 P.M.
1:30 P.M.
727
10
AE
439
1:45 P.M.
2:30 P.M.
727
11
AE
889
1:45 P.M.
2:30 P.M.
727
12
AE
852
3:30 P.M.
4:00 P.M.
727
13
AE
422/660
3:45 P.M.
5:00 P.M.
727
14
AE
9999
4:15 P.M.
5:00 P.M.
727
15
AE
591/544
5:15 P.M.
6:15 P.M.
727
16
AE
9999
5:30 P.M.
6:15 P.M.
727
17
AE
310/390
6:00 P.M.
8:00 P.M.
727
18
AE
411/428
9:00 P.M.
10:15 P.M.
727
19
CL
64
7:15 A.M.
7:45 A.M.
737
20
CL
9999
7:45 A.M.
8:30 A.M.
737
21
CL
489
11:15 A.M.
11:45 A.M.
737
22
CL
9999
11:15 A.M.
12:15 P.M.
737
23
CL
41
11:30 A.M.
12:15 P.M.
737
24
CL
9999
1:15 P.M.
2:45 P.M.
737
25
CL
50
1:45 P.M.
2:15 P.M.
737
26
CL
936
1:45 P.M.
2:15 P.M.
737
27
CL
81
4:15 P.M.
5:00 P.M.
737
28
CL
493
8:30 P.M.
9:00 P.M.
737
29
RX
161
10:15 A.M.
10:45 A.M.
MD8
30
RX
321/844
4:45 P.M.
5:45 P.M.
MD8
TABLE 10-13
Simulated Airline Schedule on Typical Day in the Peak Month in the
Design Year for Example Problem 10-2
449
450
Airport Design
The determination of the number of aircraft gates required at an airport is shown by constructing ramp charts in Example Problem 10-3.
Example Problem 10-3 Let us determine the number of gates required at an airport
based upon the design-day schedule shown in Table 10-13. Let us determine
the gate requirements under an exclusive gate-use strategy, a shared gate-use
strategy, and a common gate-use strategy. Let us assume that the scheduling and
operating practices of the airlines require that a minimum time gap of 15 min
must be allowed between the departure of a scheduled flight from a gate and
the arrival of the next scheduled flight at that gate.
Under an exclusive gate-use strategy each airline will have its own gates
which cannot be used by any other airline. To find the number of gates required
under this gate-use strategy, a graph is constructed showing time on the X axis
and the number of gates on the Y axis. To determine the minimum number of
gates required, the flight schedule of each airline must be sorted first by arrival
and then departure time. That is, two flights which have the same arrival time
are also sorted by the departure time.
In Table 10-13, the flight schedule of each airline has been sorted and a reference number is placed next to each flight for each airline. This reference number
will be placed on the ramp chart for illustrative purposes.
To determine the gate required for Alpha Express (AE) Airlines, since the
first scheduled flight is scheduled to arrive at 7:45 A.M. and scheduled to depart
at 9:30 A.M., a gate is opened on the ramp chart and the block of time from 7:45 A.M.
to 9:30 A.M. is filled in on the ramp chart to indicate that the gate is occupied
during that period of time. The next scheduled flight by AE Airlines is scheduled
to arrive at 10:15 A.M. and depart at 10:45 A.M. Since at the gate just opened up
the next scheduled arrival can be placed at this gate 15 min after the departure
of the previous aircraft, this flight may be scheduled into that gate and the block
of time from 10:15 A.M. to 10:45 A.M. is filled in. The next scheduled flight of AE
Airlines is scheduled to arrive at 10:15 A.M. and depart at 11:00 A.M. However, this
flight cannot be scheduled into the first gate since that gate is occupied during
part of that period of time.
Therefore, a new gate is opened up on the ramp chart to accommodate this
aircraft and the block of time from 10:15 A.M. to 11:00 A.M. is filled in at that gate.
This process is continued until all of the AE Airline flights have been assigned to
gates. As may be seen on the top portion of Fig. 10-32, to accommodate the flights
of AE Airlines four gates are required.
The same process is repeated for each airline, and as shown in the middle
and bottom portions of Fig. 10-32, this results in three gates being required for
Coastal Link (CL) Airlines and one gate being required for Regional Express
(RX) Airlines.
Therefore, under an exclusive gate-use strategy, this flight schedule requires
eight gates to accommodate the airline schedule at the airport.
For the construction of a shared gate-use strategy ramp chart, let us assume that
CL and RX Airlines will share gates at the airport and that AE Airlines will have
exclusive-use gates. Therefore, the ramp chart for AE Airlines does not change but
the ramp chart for the shared-gate-use airlines must be constructed by first sorting
all of the flights of CL and RX Airlines together by arrival time and departure time
as shown in Table 10-14. Using the procedure above, Fig. 10-33 is the required
ramp chart. It is seen that though AE Airlines requires four gates, RX and CL
Airlines now only require at total of three gates. Therefore, the shared-gate-use
strategy results in one less gate at the airport to accommodate the design-day
flight schedule.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
6a
1
8
12p
10
1
2
AE Gates
2
7
19
20
10
12a
10
12a
18
16
17
24
22
27
26
20
10
28
25
23
8
8
9
21
1
6a
13
8
3
RX Gates
6
12 14 15
11
5
4
C Gates
10
4
3
1
6
3
2
Hour of the Day
4
2
30
12p
2
4
6
8
Hour of the Day
FIGURE 10-32 Ramp chart for exclusive gate use for Example Problem 10-3.
Ref
No.
Flight
Airline
Time of
Arrival
Departure
Aircraft
1
CL
Number
64
7:15 A.M.
7:45 A.M.
737
2
CL
9999
7:45 A.M.
8:30 A.M.
737
3
RX
161
10:15 A.M.
10:45 A.M.
MD8
4
CL
489
11:15 A.M.
11:45 A.M.
737
5
CL
9999
11:15 A.M.
12:15 P.M.
737
6
CL
41
11:30 A.M.
12:15 P.M.
737
7
CL
9999
1:15 P.M.
2:45 P.M.
737
8
CL
50
1:45 P.M.
2:15 P.M.
737
9
CL
936
1:45 P.M.
2:15 P.M.
737
10
CL
81
4:15 P.M.
5:00 P.M.
737
11
RX
4:45 P.M.
5:45 P.M.
MD8
12
CL
8:30 P.M.
9:00 P.M.
737
TABLE 10-14
321/844
493
Simulated Airline Schedule on Typical Day in the Peak Month
in the Design Year for CL and RX Airlines for Shared-Gate-Use Strategy for
Example Problem 10-3
451
452
Airport Design
6a
8
1
1
AE
Exclusive
Gates
6
2
3
2
7
5
1
11
3
7
10
10
12a
16
10
8
6
8
12a
17
5
3
6a
13
10
18
9
4
2
8
12 14 15
8
4
1
CL and RX
2
Shared
Gates
10
4
3
Hour of the Day
4
6
2
12p
10
12
11
9
12p
2
4
6
8
Hour of the Day
FIGURE 10-33 Ramp chart for shared gate use for Example Problem 10-3.
For the common use-gate strategy, all of the flights of all of the airlines are
sorted together by arrival time and departure time and the ramp chart similarly
constructed. If this is done, the ramp chart in Fig. 10-34 results which shows that
under a common gate-use strategy only five gates are required at the airport to
accommodate the design-day schedule.
The peak hour for gate use occurs around 1:00 P.M. and the peak hour gate
utilization is defined as the gate time demanded divided by the gate time supplied in the peak hour. The aircraft demand 210 min of gate time in the peak
hour and the gate time supplied is 480 min, 420 min, or 300 min for the exclusive,
shared and common gate-use strategies, respectively. Therefore, the peak hour
gate utilization is 0.44, 0.50, or 0.70 by each of the gate-use strategies.
6a
1
Common
Gates
for All
Airlines
2
3
8
1
10
12p
4
9 13
2
5
10
3
6
7
4
6a
8
10
16
6
8
21 23 26
14 17
11
15 18
12
19
8
5
Hour of the Day
2
4
22
27
24
10
12a
10
12a
29
30
28
25
20
12p
2
4
6
8
Hour of the Day
FIGURE 10-34
Ramp chart for common gate use for Example Problem 10-3.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
All of the aircraft on the design-day schedule in this are narrow-bodied aircraft. If some are wide-bodied aircraft, the sorting would be done separately
for the wide-bodied and narrow-bodied aircraft. To minimize the number of
wide-bodied gates, the wide-bodied aircraft would be assigned to the ramp chart
first and then the narrow-bodied aircraft would be assigned, recognizing that a
narrow-bodied aircraft may use a wide-bodied gate.
Gates at most airports vary within the range of three to five gates
per million annual passengers. The total number of gates may have to
be modified if not all gates can handle all types of aircraft. This is
particularly important at airports where the aircraft mix includes a
considerable amount of large and small aircraft. In such situations,
and when data are available, it would be preferable to compute gate
requirements separately for the different types of aircraft, keeping in
mind that the large gates can be used to handle small aircraft, while
the reverse is not true. It is also desirable to calculate the gate requirements separately for different types of traffic. For example, at a large
international airport separate calculations may be performed for
domestic gates, for international gates, and for charter gates.
Gate Size
The size of a gate depends not only on the size of aircraft which it is to
accommodate and but also on the type of parking used, that is, nose-in,
parallel, or angled parking. The size of the aircraft determines the
space required for parking as well as for maneuvering. Furthermore,
the size of aircraft determines the extent and size of the servicing
equipment that needs to be provided to service the aircraft. The type
of parking used at the gates affects the size since the area required to
maneuver into and out of a gate varies depending on the way the aircraft is parked.
In view of the large number of factors that affect the size and exact
layout of gates, it is desirable to consult the airlines at an early stage in the
design process in order to determine the manner in which they plan to
maneuver aircraft and the types of servicing facilities they plan to use.
The design of the gates can be worked out with the aid of procedures and dimensions provided by the FAA [6, 7], ICAO [3], and the
International Air Transport Association [12]. Included in these references are diagrams which show various dimensions required for different types of aircraft and various parking and maneuvering conditions.
Chapter 6 discusses the layout of ramp areas to accommodate aircraft.
While detailed design of aircraft gates requires the aid of charts such
as those found in the airplane characteristics manuals published for aircraft, it is usually sufficient for preliminary planning to adopt uniform
dimensions between centers of gates and to use these for sizing the
apron gate area. The dimensions depend on the type of aircraft. The
typical dimensions for the case where aircraft enter a gate under their
own power and are pushed out by a tractor are given in Table 10-15.
453
454
Taxi-Out∗
Push-Out
A
B
C
L
W
Area yd2
L
W
Area yd2
FH-227
103 ft 1 in
115 ft 2 in
1319
148 ft 10 in
140 ft 2 in
2318
YS-11B
106 ft 3 in
124 ft 11 in
1474
171 ft 0 in
149 ft 11 in
2850
BAC-111
123 ft 6 in
113 ft 6 in
1557
130 ft 0 in
138 ft 6 in
2001
DC-9-10
134 ft 5 in
109 ft 5 in
1634
149 ft 2 in
134 ft 5 in
2228
DC-9-21,30
149 ft 4 in
113 ft 4 in
1880
149 ft 0 in
138 ft 4 in
2290
727 (all)
173 ft 2 in
128 ft 0 in
2463
194 ft 0 in
153 ft 0 in
3298
737 (all)
120 ft 0 in
113 ft 0 in
1507
145 ft 4 in
138 ft 0 in
2228
B-707 (all)
172 ft 11 in
165 ft 9 in
3188
258 ft 0 in
190 ft 9 in
5468
B-720
156 ft 9 in
150 ft 10 in
2627
228 ft 0 in
175 ft 10 in
4454
DC-8-43, 51
170 ft 9 in
162 ft 5 in
3081
211 ft 10 in
187 ft 5 in
4411
D
DC-8-61, 63
207 ft 5 in
168 ft 5 in
3882
252 ft 4 in
193 ft 5 in
5423
E
L-1011
188 ft 8 in
175 ft 4 in
3676
263 ft 6 in
200 ft 4 in
5865
DC-10
192 ft 3 in
185 ft 4 in
3959
291 ft 0 in
210 ft 4 in
6801
B-747
241 ft 10 in
215 ft 8 in
5795
328 ft 0 in
240 ft 8 in
8771
F
∗
Aircraft
Group
L = perpendicular to face of building; W = parallel to face of building.
Source: Federal Aviation Administration [50].
TABLE 10-15 Comparison of Apron Parking Envelope Dimensions for Aircraft Push-out and Taxi-out Gate Use for
Nose-In Configuration
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Aircraft Parking Type
Aircraft parking type refers to the manner in which the aircraft is
positioned with respect to the terminal building and to the manner in
which aircraft maneuver in and out of parking positions. It is an
important factor affecting the size of the parking positions and consequently the apron gate area. Aircraft can be positioned at various
angles with respect to the terminal building line and can maneuver
into and out of parking positions either under their own power or
with the aid of towing equipment. With aircraft towing it is possible
to reduce the size of parking positions. It is advisable in choosing
among alternative parking types to consult with the airline in question, as different airlines have different preferences for the available
systems. It is also advisable in adopting a parking type to take into
consideration the objective of protecting passengers from the adverse
elements of noise, jet blast, and weather, and the operating and maintenance costs of needed ground equipment.
The aircraft parking types which have been successfully used at a
variety of airports and should be evaluated in any airport planning
study include nose-in, angled nose-in, angled nose-out, and parallel.
These parking types are shown in Fig. 10-35 and are discussed separately below.
Nose-In Parking
In this configuration the aircraft is parked perpendicular to the building line with the nose as close to the building as permissible. The
aircraft maneuvers into the parking position under its own power. In
order to leave the gate, the aircraft has to be towed out a sufficient
distance to allow it to proceed under its own power. The advantages
of this configuration are that it requires the smallest gate area for a
given aircraft, causes lower noise levels as there is no powered turning movement near the terminal building, sends no jet blast toward
the building, and facilitates passenger loading as the nose is near the
building. Its disadvantages include the need for towing equipment
Nose-In
Parallel
Angled Nose-In
Angled Nose-Out
FIGURE 10-35 Aircraft parking types.
455
456
Airport Design
and the nose is too far from the building to effectively use the rear
doors for passenger loading.
Angled Nose-In Parking
This configuration is similar to the nose-in configuration except that
the aircraft is not parked perpendicular to the building. The configuration has the advantage of allowing the aircraft to maneuver in and
out of the gate under its own power. However, it requires a larger gate
area than the nose-in configuration and causes a higher noise level.
Angled Nose-Out Parking
In this configuration the aircraft is parked with its nose pointing away
from the terminal building. Like the angled nose-in configuration, it
has the advantage of allowing aircraft to maneuver in and out of gate
positions without towing. It does require a larger gate area than the
nose-in position, but less than the angled nose-in. A disadvantage of
this configuration is that the breakaway jet blast and noise are pointed
toward the building when the aircraft starts its taxiing maneuver.
Parallel Parking
This configuration is the easiest to achieve from the aircraft maneuvering standpoint. In this case noise and jet blast are minimized, as
there are no sharp turning maneuvers required. It does require, however, a larger gate position area, particularly along the terminal building frontage.
It is evident that no one parking type can be considered ideal. For
any planning situation, all the advantages and disadvantages of the
different systems have to be evaluated, taking into consideration the
preference of the airline that will be using the gates.
Apron Layout
Another factor that affects apron size and installation requirements is the
apron layout. This refers to the manner in which the apron is arranged
around the terminal building. The apron layout depends directly on the
way the aircraft gate positions are grouped around the buildings and
on the circulation and taxiing patterns dictated by the relative locations of the terminal buildings and the airfield system.
Aircraft are grouped adjacent to the terminal building in a variety
of ways depending on the horizontal terminal concept used. These
groupings are referred to as parking systems and are classified as the
frontal or linear system, the finger or pier system, the satellite system,
and the open apron or transporter system. Each of these were discussed and illustrated earlier.
The choice of aircraft parking system is, naturally, strongly influenced by the horizontal passenger processing concept adopted. For
each there are positive and negative attributes that must be weighed
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
against each other. While the open apron system has the advantage of
separating the aircraft and the terminal building from one another, it
does require buses or mobile lounges for the conveyance of passengers between them. These vehicles use the apron, and their circulation patterns need careful planning to avoid interference with the
flow of aircraft and other service vehicles. While the finger system
allows the efficient expansion of gate positions and the efficient use of
terminal building space, it may lead to long passenger walking distances if allowed to become excessively long. The frontal system is
suitable for the gate arrival processing concept. Other features of
these systems were discussed earlier in this chapter.
Apron Circulation
In designing the apron layout it is important to take into account aircraft circulation, particularly the movement of aircraft within the
apron gate area and from this area to the taxiways. When the traffic
volume is high, it is desirable to provide a taxilane on the periphery of
the apron. It is also important to allow sufficient space to permit easy
access of aircraft to gates. This is particularly important when pier fingers are used for aircraft parking and the fingers are parallel to each
other. Sufficient space must be provided between the fingers to allow
aircraft ready access to the gates. The separation between fingers
depends on their length and on the size of aircraft to be accommodated.
The longer the finger, the more aircraft gates can be accommodated.
However, the increase in the number of gates may necessitate the provision of two taxilanes instead of one between the fingers to provide
circulation without excessive delay. One taxilane will probably suffice
when there are no more than five or six gates on each side of a finger.
A large number of gates may require two taxilanes.
Passenger Conveyance to Aircraft
Depending on the passenger processing system used, the type of aircraft parking, and the parking system layout, any of three methods of
conveyance can be used between the building and the aircraft. These
are walking on the apron, walking through aircraft building connectors such as passenger loading bridges, and by mobile conveyance
using any of a variety of apron vehicles.
The first method can be employed with all processing and parking systems. However, as the number of parking positions and the
apron size increases, it becomes impractical to use walking for the
conveyance of passengers. The economic appeal of this method is
overcome by the need to protect the passengers from the elements
and from the hazards of walking on the apron.
The second method can be employed for all systems other than
where open apron parking is used. A variety of fixed and movable
loading systems have been developed for passenger conveyance.
457
458
Airport Design
Terminal
building
Aircraft
door
Apron
FIGURE 10-36 Typical aircraft loading bridge.
Most common among these are the nose bridges, which are short connectors suitable for use when the aircraft door comes close to the
building such as with nose-in parking. Another common system is
the telescoping loading bridge. These have the flexibility of extending from the building to reach the aircraft door and of swinging to
accommodate different types of aircraft. A typical boarding bridge is
shown in Fig. 10-36.
Apron Utility Requirements
Aircraft need to be serviced at their respective gates. Thus certain fixed
installations may be required on the apron. Apron congestion is always
a problem and, hence, there is a definite trend at larger airports toward
replacing mobile servicing equipment with fixed facilities.
Aircraft Fueling
Aircraft are fueled at the apron by fuel trucks, fueling pits, and
hydrant systems. At the smaller and even the larger airports the use
of fuel trucks is prevalent, but the pattern is changing in favor of the
hydrant system at airports requiring large amounts of fuel.
The principal advantage of fuel trucks is their flexibility. Aircraft can be fueled anywhere on the apron, the units can be added
or taken away according to need, and the system is relatively economical insofar as airport management and airline operations are
concerned. There are, however, disadvantages associated with the
use of fuel trucks. Large jet transports require a considerable amount
of fuel, from nearly 8000 gal (U.S.) for the McDonnell Douglas MD-88
to almost 50,000 gal (U.S.) for the Boeing 747-100. Two refueler units
are normally required, one under each wing. For the large jets,
standby units are sometimes required if the fuel requirements are in
excess of two units. This means that there are a large number of vehicles on the apron during peak periods, creating a potential hazard
of collision with personnel, other vehicles, and aircraft. Since each
truck carries a considerable quantity of fuel, it also constitutes a
potential fire hazard when moving around on an apron where a
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
number of other activities are taking place. Trucks are large and
awkward and take up valuable space in the operations area. When
a truck is empty, it must return to the storage area for refueling
before it can be used again. Thus extra trucks must be provided for
use during the time when other trucks are being reloaded. When
refueling trucks are not in use, parking space must be provided for
these vehicles. Modern refuelers are approximately 40 ft in length
and weigh as much as 83,000 lb. The capacity of the larger trucks is
approximately 8000 gal. For the larger refuelers axle loads are in
excess of the legal limits on highways, and, consequently, the airport designer must provide adequate pavement strengths to support these vehicles.
The hydrant system is used at most large airports. In this system, a
large fuel storage area, often called a fuel farm, is located on the airport
property. Fuel is transferred from the fuel storage area to aircraft gate
positions through a system of pipes located below the pavement surface.
A special valve is mounted in a box in the pavement flush with the pavement surface at each gate position. A special vehicle, a hydrant dispenser, with a hose, meter, filter, and air eliminator is used to connect
the fuel supply to the aircraft. One end of the hose has a specially
designed valve which is coupled to the valve installed in the pavement. This hose feeds into the meter, filter, and air eliminator, from
which another hose, usually on a reel, is led to the fuel intakes on the
aircraft.
The principal advantages of the hydrant system are that a continuous supply of fuel is available at the gates, it is safely carried
underground, and fuel trucks are eliminated from the apron. The
principal disadvantage is that vehicles are not entirely removed from
the apron. However, because of their small size, hydrant dispensers
reduce possible collision damage to a minimum.
The amounts of fuel required at many airports are so large that,
regardless of the type of fueling system used, a central fuel storage
area in the vicinity of the landing area is required. If the hydrant system is used, provision must be made for installing pipes from the
storage area to the apron.
The location of the hydrant valves at an individual gate will depend
upon the location of the fueling connections in the wings of the aircraft
occupying the gates. It is desirable that the hose line from the hydrant
dispenser to the intakes in the wings not exceed 20 to 30 ft. If a wide
variety of aircraft are to be serviced at a gate position, the precise spacing of the hydrant valves should be established in consultation with
the airlines. The number of hydrants required per gate position depends
not only on the type of aircraft but also on the number of grades of fuel
required. Each grade of fuel requires a separate layout.
At a number of airports, hydrant systems are installed by oil companies which contract for fuel with a particular airline or airlines. It is
not uncommon to have the hydrant system and fuel trucks operate
459
460
Airport Design
simultaneously at the same airport. The trend at the large airports is
definitely toward the hydrant system.
Electrical Power
Electrical power is required on the apron for the servicing of aircraft
prior to engine starting. External electrical power is also often required
for starting the engines. Power requirements vary widely for different aircraft. Consequently, it is necessary to consult with the airlines
concerning this matter. Power can be supplied by mobile units or by
fixed installations in the pavement. The latter is preferable since it
removes the need for a vehicle and to some extent reduces noise
which emanates from a motor generator set. For a fixed installation,
the most satisfactory technique is to bury conduits under the apron,
terminating them at supply points some distance from the hydrant
valves but convenient to the aircraft.
Recently, there has been a trend toward fixed ground power and
air conditioning systems using terminal power sources. The need for
these facilities has grown due to the costs of providing power and
conditioned air to aircraft during servicing times at the apron gate by
using the power generated by the auxiliary power unit on the aircraft. Considerable operating cost economies have been reported in
the use of such systems [27].
Aircraft Grounding Facilities
Grounding facilities will be required on the apron to provide protection of parked aircraft and fuel trucks from static discharge, particularly during fueling operations. The location of the grounding facility
will be governed by the location of the hydrant valves. With high
fueling rates it is essential that grounding facilities be provided.
Apron Lighting and Marking
Adequate lighting and marking are essential on an apron. Wherever
possible, each gate should be floodlighted. Floodlighting removes the
need for mobile equipment to use headlights, which experience has
shown to cause confusion and glare. A system of elevated lights appears
to offer the best method of providing apron illumination. Where pier
fingers are utilized, the lights can be attached to the fingers. Lighting
should be located so as to provide uniform illumination of the apron
area yet not cause glare to the pilot.
When personnel are servicing an aircraft, there is a need for lighting its underside and far side, if the floodlights do not provide the
necessary illumination. This can be accomplished by installing flush
lights in the pavement. When lights of this type are installed, they
should be arranged so as not to confuse the pilot insofar as guidance
to the gate position is concerned.
Painted guidelines have proved very desirable as aids to maneuvering aircraft accurately on the apron. The best guide appears to be
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
Building line
L
Parkin
g
Point “A”
(center of
turn)
L
Minimum
turning radius
Path of wing tip
C of main gear oleo
strut
angle
L
Co
fn
o
in se w
p
po ark hee
sit ed l
ion
Plane
in parked
position
10
'
4' d
io
C
5'
O
90
ut
°
of main gear oleo
strut at start of
pivot
2'
u
ra nd t
di ur
us n
in
bo
10
'
2' yellow strip
g
Point “B ”
Clearance
to bldg
line
2' spacing
5' long path of nose
wheel out bound
Path of nose wheel
inbound
FIGURE 10-37 Typical painted guidelines at gate positions.
a single line, usually the color is yellow, which is followed by the nose
gear of the aircraft. A typical layout is shown in Fig. 10-37. It is recognized that a single line will not provide precise guidance for a variety
of different aircraft. Usually the guideline is painted for the most critical aircraft using a particular gate position. Smaller aircraft can use
the same lines and maneuver without difficulty, especially if personnel on the ground are available to direct the pilot. Because of possible
fuel spillage, it is desirable to paint guidelines with special resistant
paint in areas where spillage might occur.
References
1. Access to Commercial Service Airports: The Planning and Design of On-Airport
Ground Access System Components, Final Report, F. X. McKelvey, Federal
Aviation Administration, Washington, D.C., 1984.
2. “A Decision Tool for Airport Terminal Building Capacity Analysis,” B. F.
McCullough and F. L. Roberts, Council for Advanced Transportation Studies,
University of Texas at Austin, Presented at 58th Annual Meeting of the
Transportation Research Board, Washington, D.C., January 1979.
461
462
Airport Design
3. Aerodrome Design Manual, Part 2: Taxiways, Aprons and Holding Bays, 2d ed.,
International Civil Aviation Organization, Montreal, Canada, 1983.
4. Aircraft Movement and Passenger Data for 100 U.S. Airports, Air Transport
Association of America, Washington, D.C., Periodic.
5. Airline Aircraft Gates and Passenger Terminal Space Approximations, AD/SC Report
No. 4, Air Transport Association of America, Washington, D.C., July 1977.
6. Airport Capacity and Delay, Advisory Circular AC 150/5060-5, Federal Aviation
Administration, Washington, D.C., 1983.
7. Airport Design, Advisory Circular AC 150/5300-13, Federal Aviation
Administration, Washington, D.C., 1989.
8. “Airport Gate Position Estimation Under Uncertainty,” S. Bandara and S. C.
Wirasinghe, Transportation Research Record, No. 1199, Transportation Research
Board, Washington, D.C., 1988.
9. Airport Ground Access Planning Guide, Report No. FAA- EM-80-9, U.S.
Department of Transportation, Transportation Systems Center and Federal
Aviation Administration, Washington, D.C., 1980.
10. Airport Landside: The Airport Landside Simulation Model (ALSIM), U.S.
Department of Transportation, Transportation Systems Center and Federal
Aviation Administration, Report Nos. FAA-EM-80-8 and DOT-TSC- FAA-84-4,
Washington, D.C., 1982.
11. “Airport Landside Level of Service Estimation: Utility Theoretic Approach,” K.
F. Omer and A. M. Khan, Transportation Research Record, No. 1199, Transportation
Research Board, Washington, D.C., 1988.
12. Airport Development Reference Manual, 9th ed., International Air Transportation
Association, Montreal, Canada, January 2004.
13. “Airport Terminal Designs with Automated People Movers,” L. David Shen,
Transportation Research Record, No. 1273, Transportation Research Board,
Washington, D.C., 1990.
14. Airport Terminal Flow Simulation Model, Transport Canada, Ottawa, Ontario,
Canada, 1988.
15. An Airport Passenger Processing Simulation Model, S. Hannig-Smith, Aviation
Planning Associates, Inc., Cincinnati, Ohio, January 1981.
16. “Analysis of Factors Influencing Quality of Service in Passenger Terminal
Buildings,” N. Martel and P. N. Seneviratne, Transportation Research Record,
No. 1273, Transportation Research Board, Washington, D.C., 1990.
17. “Analysis of Passenger and Baggage Flows in Airport Terminal Buildings,”
R. Horonjeff, Journal of Aircraft, American Institute of Aeronautics and
Astronautics, Vol. 5, No. 5, 1969.
18. “Analysis of Passenger Delays at Airport Terminals,” S. Yager, Transportation
Engineering Journal, American Society of Civil Engineers, Vol. 99, No. TE4, New
York, N.Y., November 1973.
19. “Analytical Models for the Design of Aircraft Terminal Buildings,” J. D. Pararas,
Masters Thesis, Massachusetts Institute of Technology, Cambridge, Mass.,
January 1977.
20. “Applications for Intra-Airport Transportation Systems,” F. X. McKelvey and
W. J. Sproule, Transportation Research Record, No. 1199, Transportation Research
Board, Washington, D.C., 1988.
21. A Review of Airport Terminal System Simulation Models, F. X. McKelvey, Final
Report, U.S. Department of Transportation, Transportation Systems Center,
Cambridge, Mass., November 1989.
22. Automobile Parking Systems Handbook, Airports Association Council InternationalNorth America, Washington, D.C., 1991.
23. Chicago Midway Airport Master Plan Study, Determination of Facility
Requirements, Working Paper No. 1, Draft, Landrum and Brown Aviation
Consultants, Chicago, Ill., 1990.
24. Collection of Calibration and Validation Data for an Airport Landside Dynamic
Simulation Model, Wilbur Smith and Associates, Federal Aviation Administration,
Washington, D.C., January 1980.
25. Conceptual Studies for Geneva Intercontinental Airport, Reynolds, Smith and Hills,
Jacksonville, Fla., March 1981.
P l a n n i n g a n d D e s i g n o f t h e Te r m i n a l A r e a
26. Demand-Capacity Analysis Ground Access Study, Draft Report, Terminal Support
Working Group, Chicago O’Hare International Airport, Landrum and Brown
Aviation Consultants, Chicago, Ill., 1990.
27. Design Guidebook—400 Hz Fixed Power Systems, Air Transport Association of
America, Washington, D.C., January 1980.
28. “Designing an Improved International Passenger Processing Facility: A
Computer Simulation Analysis Approach,” V. Gulewicz and J. Browne,
Transportation Research Record, No. 1273, Transportation Research Board,
Washington, D.C., 1990.
29. “Evaluating Performance and Service Measures for the Airport Landside,” S.
A. Mumayiz, Transportation Research Record, No. 1296, Transportation Research
Board, Washington, D.C., 1991.
30. Fort Lauderdale-Hollywood International Airport Parking Analysis, Working Paper,
Aviation Planning Associates, Inc., Cincinnati, Ohio, September 1981.
31. Ground Transportation Facilities Planning Manual, Report No. AK-69-13-000,
Airport Facilities Branch, Transport Canada, Ottawa, Ontario, Canada, 1982.
32. Greater Pittsburgh International Airport Expansion Program, New Terminal
Complex Schematic Refinement Phase, Final Report, Tasso Katselas Associates,
Inc., and Michael Baker, Jr., Inc., Pittsburgh, Pa., 1986.
33. Highway Capacity Manual, HCM2000, Transportation Research Board,
Washington, D.C., 2000.
34. “Interactive Airport Landside Simulation: An Object- Oriented Approach”, S. A.
Mumayiz and R. K. Jain, Transportation Research Record, No. 1296, Transportation
Research Board, Washington, D.C., 1991.
35. Introduction to Transportation Engineering and Planning, E. K. Morlok,
McGraw-Hill, Inc., New York, N.Y., 1978.
36. “Level of Service Design Concept for Airport Passenger Terminals: A European
View,” N. Ashford, Transportation Research Record, No. 1199, Transportation
Research Board, Washington, D.C., 1988.
37. Measuring Airport Landside Capacity, Special Report 215, Transportation Research
Board, Washington, D.C., 1987.
38. “Opportunities for Fixed Rail Service to Airports,” W. J. Sproule, International
Air Transportation, Proceedings of the 22nd Conference on International Air
Transportation, American Society of Civil Engineers, New York, N.Y., 1992.
39. “Overview of Airport Terminal Simulation Models,” S. A. Mumayiz,
Transportation Research Record, No. 1273, Transportation Research Board,
Washington, D.C., 1990.
40. Parking Structures: Planning, Design, Construction, Maintenance, and Repair, A. P.
Chrest, M. S. Smith, and S. Bhuyan, Van Nostrand and Reinhold, New York,
N.Y., 1989.
41. Pedestrian Planning and Design, J. Fruin, Metropolitan Association of Urban
Designers and Environmental Planners, New York, N.Y., 1971.
42. “Pier Finger Simulation Model,” E. E. Smith and J. T. Murphy, Graduate Report,
University of California, Berkeley, Calif, 1972.
43. Planning and Design Guidelines for Airport Terminal Facilities, Advisory Circular
AC 150/5360-13, Federal Aviation Administration, Washington, D.C., 1988.
44. Planning and Design of Airport Terminal Facilities at Non-Hub Locations, Advisory
Circular, AC 150/5360-9, Federal Aviation Administration, Washington, D.C.,
1980.
45. Planning Guide for Airport Ground Transportation Facilities, Report No. AK-69-13,
Airport Facilities Branch, Transport Canada, Ottawa, Ontario, Canada, 1982.
46. “Planning of Intra-Airport Transportation Systems,” W. J. Sproule, Ph.D.
Dissertation, Michigan State University, East Lansing, Mich., 1985.
47. “Simulating the Turnaround Operation of Passenger Aircraft Using the Critical
Path Method,” J. B. Braaksma, Doctoral Thesis, Waterloo University, Waterloo,
Canada, 1970.
48. Survey of Airport Ground Access, U.S. Aviation Industry Working Group,
Washington, D.C., June 1981.
49. The Apron and Terminal Building Planning Report, Report No. FAA-RD-75-191,
Federal Aviation Administration, Washington, D.C., July 1975.
463
464
Airport Design
50. The Apron Terminal Complex, Ralph M. Parsons Company, Federal Aviation
Administration, Washington, D.C., September 1973.
51. “The Design of the Airside Concourses (The New Denver International
Airport),” J. M. Suehiro, E. K. McCagg, and J. M. Seracuse, International Air
Transportation, Proceedings of the 22nd Conference on International Air
Transportation, American Society of Civil Engineers, New York, N.Y., 1992.
52. The FAA’s Airport Landside Model, Analytical Approach to Delay Analysis, Report
No. FAA-AVP-78-2, Federal Aviation Administration, Washington, D.C.,
January 1978.
53. “The Movement of Air Cargo between Cargo Terminals and Passenger Aircraft
Gates—Airport Planning Considerations,” R. J. Roche, Graduate Report,
Institute of Transportation and Traffic Engineering, University of California,
Berkeley, Calif., 1972.
54. “The Planning of Passenger Handling Systems,” A. Kanafani and H. Kivett,
Course Notes, University of California, Berkeley, Calif., 1972.
55. Trip Generation, 8th ed., Institute of Transportation Engineers, Washington D.C.,
2008.
56. “Use of an Analytical Queueing Model for Airport Terminal Design,” F. X.
McKelvey, Transportation Research Record, No. 1199, Transportation Research
Board, Washington, D.C., 1988.
57. Recommended Security Guidelines for Airport Planning, Design and
Construction, Transportation Security Administration, Washington, D.C., June
2006.
58. Airport Passenger Terminal Planning and Design, ACRP Report 25, Airport
Cooperative Research Program, Transportation Research Board, Washington,
D.C., 2010.
59. Guidebook for Planning and Implementing Airport People Mover Systems
at Airports, ACRP Project 03-06, Airport Cooperative Research Program,
Transportation Research Board, Washington, D.C., 2010.
60. Intermodal Ground Access to Airports—A Planning Guide, Report DOTT-97-15, US DOT Federal Highway Administration and Federal Aviation
Administration, Washington, D.C., December 1996.
PART
Special Topics
in Airport
Planning and
Design
CHAPTER 11
Airport Security
Planning
CHAPTER 13
Finance Strategies
for Airport Planning
CHAPTER 12
Airport Airside
Capacity and Delay
CHAPTER 14
Environmental Planning
CHAPTER 15
Heliports
3
This page intentionally left blank
CHAPTER
11
Airport Security
Planning
Introduction
One of the most significant issues facing airports today is that of
airport security. Most users of commercial service airports are subjected to security infrastructure, policies, and procedures within the
terminal area; however, airport security concerns all areas and users
of the airport.
Safety and security are often considered synonymous; however,
the discussion of one invariably invokes reference to the other. Safety
is the freedom from the occurrence or risk of injury, danger, or loss to
a person and his or her property that is caused unintentionally. A few
safety examples in airport design would be actions to prevent a fall
on a slippery sidewalk or floor, presence of wildlife on a runway, or
loss of an engine due to a bird strike. As aviation grew, government
agencies have developed many regulations, standards, and guidelines related to safety. These are covered in numerous documents for
airfield, terminal, and ground access planning and design, such as
FAA Advisory Circulars, ICAO design manuals, building codes, state
highway design manuals, and many others.
Security is the freedom from the occurrence or risk of injury,
danger or loss to a person and their property that is caused intentionally through acts of violence. To understand the task of prevention it
is necessary to identify the perpetrators of violence and their methods.
There three groups most commonly considered are terrorists, criminals, and disruptive passengers.
A terrorist is a person or group who uses or advocates the use of
violent or threat to intimidate or coerce and these actions are often
for political purposes. Terrorist acts are not impulsive acts, but rather
are the results of careful planning that evaluates the weak points in
the target before taking action. This careful planning aspect of terrorism
makes prevention difficult, and agencies have applied the principle
of layered security to prevent acts of terrorism. Several layers of
467
468
Special Topics in Airpor t Planning and Design
security are in place and failure of a single layer does not mean that
the entire system will be breached.
A category of terrorist is a suicide bomber and this terrorist presents an even more difficult challenge in security. Suicide terrorism is
a simple and low-cost operation in which the terrorist dies. It requires
no escape routes or complicated rescue operations. The terrorist can
choose the exact time, location, and circumstances of the attack and
this has an immense impact on the public due to the overwhelming
sense of helplessness. If successful, there will be no terrorists to interrogate because death will be certain.
There may be several definitions of a criminal, but for the purpose
of airport and aviation protection against acts of crime, criminals are
persons who are performing acts that create risk of injury, danger, or
loss to persons or property. There are several possible crimes that
may occur at an airport. One example is cargo theft. Criminals’ intent
on cargo theft may carry out an airport invasion, enter the air operations area by force and steal cargo from the aircraft while it is on the
ground, or they may board the aircraft, hijack the flight, and force the
pilot to land at a predetermined location where the cargo is offloaded. In both cases, the criminals have foreknowledge of specific
cargo, flights, and ways to circumvent security. A subcategory of
criminal would be the corrupt insider. This is a person with knowledge about shipments and security procedures who reveals this
information to criminals.
A disruptive passenger is a person who demonstrates aberrant,
abnormal, or abusive behavior at an airport or on a commercial flight.
Initially, this person had no intent to cause harm but an event has
happened that upsets him or her. It may be caused by alcohol consumption before and during a flight, frustration with airport passenger processing, restrictions, or other reasons.
History of Airport Security
In the early days of civil aviation, the greatest concerns were related
to the safety of flight and there was little concern over airport or aviation security. Aviation security first became an issue in 1930 when
Peruvian revolutionaries seized a Pan American mail plane with the
aim of dropping propaganda leaflets over Lima. Between 1930 and
1958, several hijackings were reported, mostly committed by eastern
Europeans seeking political asylum. The world’s first fatal aircraft
hijacking took place in July 1947 when three Romanians killed an aircrew member.
The first major act of criminal violence against a U.S. air carrier
occurred in November 1955, when Jack Graham placed a bomb in
baggage belonging to his mother. The bomb exploded in flight,
killing all 33 people on board. Graham had hoped to collect on his
Airport Security Planning
mother’s insurance policy, but instead was found guilty of sabotaging an aircraft and sentenced to death. A second such act occurred
in January 1960, when a heavily insured suicide bomber killed all
abroad a National Airlines flight. As a result of these two incidents,
demand for baggage inspection at airports began.
With the rise of Fidel Castro in Cuba in 1959 came a significant
increase in the number of aircraft hijackings, first by those wishing to
escape Cuba, then by those hijacking U.S. aircraft to Cuba. Over the
next several years, the number of hijacking incidents increased and
peaked in the late 1960s. Hijacking became a terrorist act for negotiation with a government body or airline. A program requiring airlines
to screen passengers who fit a hijacker profile began in the late 1960s,
but hijacking continued so stronger action was taken. The first airport
security regulations were implemented in the United States in 1972
and screening of all passengers and their carry-on items began in
January 1973.
Under the provisions of Federal Aviation Regulations Part 107—
Airport Security, all airports were required to prepare and submit
a security program to the FAA that would include the following
elements:
• Identification of an air operations area (AOA), that is, those
areas used or intended for landing, takeoff, and maneuvering
of aircraft
• Identification of those areas with little or no protection against
unauthorized access because of lack of adequate fencing,
gates, doors, or other controls
• A plan to upgrade the security of air operations with a
timetable for each improvement project
Airports were required to implement an airport security plan and
were required to have all persons and vehicles that are allowed in the
AOA suitably identified. Airport employees allowed in the AOA
were subject to background checks prior to receiving proper identification and permission to enter the air operations area.
These measures paid off and the number of hijackings decreased
significantly. In June 1985, Lebanese terrorists diverted a TWA flight
leaving Athens for Beirut. One passenger was murdered during this
two-week ordeal. This hijacking and an upsurge in Middle East terrorism resulted in several U.S. actions including the use of federal air marshals on flights. On December 21, 1988, a bomb destroyed Pan American flight 103 over Lockerbie, Scotland, and all people abroad the
London to New York flight were killed. Investigators found that a
bomb concealed in a radio-cassette player had been loaded on the
plane in Frankfurt, Germany. Security measures were immediately put
into effect for U.S. carriers at European and Middle Eastern airports
after the Lockerbie bombing and one was the requirements to x-ray or
469
470
Special Topics in Airpor t Planning and Design
search all checked baggage and reconcile boarded passengers with
their checked baggage, in a process known as positive passenger baggage matching. Legislation in the United States also called for increased
focus on developing technology and procedures for detecting explosives and weapons. Throughout the 1990s, FAA sponsored research on
new equipment to detect bombs and weapons and made several
improvements to upgrade security screening procedures at airports.
The most significant event in our generation was the hijacking
and crashing of aircraft into the World Trade Center and Pentagon
Building on September 11, 2001. In response to this event, the Aviation
and Transportation Security Act was signed which made several radical
changes to airport security in the United States. The Transportation
Security Administration (TSA) was formed to develop and enforce
new security guidelines for aviation in the United States. In 2003, the
TSA along with the Coast Guard, Customs Service, and Immigration
and Naturalization Service, was formally moved into the new United
States Department of Homeland Security. All regulations regarding
the security of airport and other civil aviation operations in the United
States are now a TSA responsibility and are published under Title 49
of the Code of Federal Regulations (49 CFR—Transportation). TSA
employees were hired and given responsibilities of all passenger and
baggage screening at commercial service airports.
Since 2001, there have been a number of additional attempts to
perform terrorist acts on the commercial aviation system around the
world. As a result, security policies at the world’s airports are constantly changing, primarily in reaction to these ever evolving threats.
Airport Security Program
Every airport in the United States that is operating under Federal
Aviation Regulations Part 139—Airports Serving Certain Air Carrier
Operations, must have an Airport Security Program (ASP). The program defines specific areas of the airport that are subject to various
security measures and procedures. These areas include air operations
areas, secure areas, sterile areas, SIDA areas, and exclusive areas.
Figure 11-1 shows a general depiction of the different areas at a typical commercial airport.
Air operations area (AOA) is the portion of the airport in which
security measures are carried out. It includes aircraft movement
areas, aircraft parking areas, loading ramps, safety areas for aircraft
use, and adjacent areas, such as general aviation.
Secure area is the area where commercial air carriers load and
unload passengers and baggage. Specific security measures are specified in 49 CFR Part 1542—Airport Security, 49 CFR 1544—Aircraft
Operator Security; Air Carriers and Commercial Operators, and
49 CFR Part 1546—Foreign Air Carrier Security.
Perimeter of entire airport surrounded by fence.
Secured area/
SIDA’
Secured area/
SIDA
AOA/
SIDA
Taxiing areas
and runways
Secured area/
SIDA
Sterile
area
Baggage loading
Screening checkpoint
Passenger boarding
gates
Secured area/
SIDA
Public area
Check-in
Specified airport areas
requiring ID badges
Pick-up and drop-off
areas
Secured area/
SIDA
Secured/Security Identification Display Area (SIDA) Air Operations Area (AOA)
FIGURE 11-1 Airport security areas [9].
Sterile area
471
472
Special Topics in Airpor t Planning and Design
Sterile area is the part of the airport terminal in which passengers
have gained access by passing through TSA passenger screening
checkpoints or security. In the past, visitors were permitted in this
area at some airports, but today only ticketed passengers are permitted in the sterile area.
Security identification display area (SIDA) includes the secure area
and possibly other areas of the airports. All persons in this area must
display proper identification or be accompanied by an authorized
escort.
Exclusive area includes aircraft storage and maintenance hangers,
air cargo facilities, and fixed-base operators (FBOs) serving general
aviation and charter aircraft.
Areas that do not fall under the above definitions are considered
public areas and are not directly subject to TSA security regulations
concerning restricted access. These areas would include portions of
the airport terminal lobbies, automobile parking areas, and curb
frontage.
Planning for security is an integral part of any project undertaken
at an airport. The most efficient and cost-effective method of instituting security measures into any facility or operation is through advance
planning and continuous monitoring throughout the project. Since
the creation of the TSA, the authority to ensure the inclusion of security systems, methods, and procedures is the responsibility of TSA.
The TSA must approve the required airport security program which
describes how the airport will meet the security requirements of Federal Aviation Regulations Part 139. To assist airport planners, TSA has
prepared several documents that present guidance for incorporating
security considerations into the planning, design, construction, and
modifications for airport infrastructure, facilities, and operational
elements [8, 9]. These documents are available on the TSA website at
http://www.tsa.gov. The information presented in these documents is
expected to be revised and updated periodically as regulations, security
requirements, and technology change. The TSA report “Recommended
Security Guidelines for Airport Planning, Design, and Construction” is
an invaluable introduction or primer on airport security. It contains procedures for examining security issues, “checklists” for security facilities,
and methodologies for vulnerability/risk assessment, flow modeling,
space planning, and other aspects of security planning.
Security at Commercial Service Airports
The Aviation and Transportation Security Act and the formation of the
TSA have contributed to changing rules, regulations, policies, and
procedures for airport security. At commercial service airports,
many aspects of security will be invisible to air passengers. However, there are a few airport security components that passengers do
Airport Security Planning
experience—passenger screening, baggage screening, employee identification, controlled access, and perimeter security.
Passenger Screening
In the United States, passenger and baggage screening has undergone
a major overhaul following the terrorist attacks of September 11, 2001,
and as of 2003, passenger and baggage security screening is managed
and operated by the TSA. Prior to the TSA, passenger and carry-on
baggage screening fell under the responsibility of the air carriers
whose aircraft provided passenger service at the airport, and the air
carriers would typically subcontract security responsibilities to private security firms. There have been significant impacts on airport terminal planning and operations, and screening policies and procedures
continue to evolve.
Passenger screening facilities (Fig. 11-2) include an automated
screening process, conducted by a magnetometer that attempts to
screen for weapons carried on by a passenger that are metallic in content. As a passenger walks through a magnetometer, the presence of
metal is detected. If a sufficient amount of metal is detected, based on
the sensitivity setting on the magnetometer, an alarm is triggered.
Passengers who trigger the magnetometer are then subject to a manual
search by a screener. A manual search may range from a check with a
handheld wand to a manual pat down. Most recently, advanced
screening technologies have been introduced to screen for nonmetallic
threats, such as powder or liquid explosives.
FIGURE 11-2 Passenger screening checkpoint.
473
474
Special Topics in Airpor t Planning and Design
Carry-on baggage screening facilities are located at security screening stations to examine the contents of passengers’ carry-on baggage
for prohibited items such as firearms, sharp objects that may be used
as weapons, or plastic or chemical-based trace explosives. All carry-on
baggage is first inspected through the use of an x-ray machine. Bags
selected because of suspicions as result of the x-ray examination, or
selected on a random basis, are further inspected through the use of
explosive trace detection equipment or manual search. In addition,
personal electronic items such as laptop computers or cellular phones
are frequently inspected by being turned on and operated. In recent
years, TSA procedures have mandated more scrutiny, including a
wider range of prohibited items, more thorough hand searches,
removal of shoes for inspection, and identification checks.
Each airport and airport terminal is unique. The location and size
of the passenger screening area depends on several factors including
the overall design of the airport and the number of passengers to be
processed. As a minimum, a passenger screening area will have one
walk-through metal detector and one x-ray device. Figure 11-3 shows
the typical layout and elements for a basic station. As the passenger
demand grows additional checkpoint lanes and equipment will be
required. Guidance and methodologies for planning are provided in
TSA reports [8].
FIGURE 11-3 Typical passenger screening checkpoint layout and elements [8].
Airport Security Planning
Baggage Screening
In 2003, TSA mandated that every piece of checked baggage must be
screened by certified explosive detection equipment prior to being
loaded onto air carrier aircraft. This requirement is known as the
100 percent EDS rule. The primary piece of equipment used to perform checked-baggage screening, the explosive detection system
(EDS), uses computed tomography technology similar to the technology found in medical CT scan machines, to detect and identify metal
and trace explosives that may be hidden in baggage. EDS equipment
has been incorporated into the outgoing baggage processing as shown
in Fig. 11-4. The outbound baggage handling system becomes very
complex as the number of bags to be processed increases. Due to
space constraints and the mandated schedule for implementation,
Baggage loaded
onto airplane
Step 2b
If baggage tests
positive for
explosives
during secondary
screening, TSA
screeners are
required to notify
appropriate
officials.
Step 2a
Step 1b
Step 1a
When an EDS machine alarms,
indicating the possibility of
explosives, TSA
screeners, by
reviewing
computergenerated images
of the inside of the
bag, attempt to
determine whether
or not suspect
item(s) are in fact
explosive materials.
If baggage passes
secondary screening it
is loaded onto airplane
ETD machine
for secondary screening
Conveyor belt
leading to airplane
EDS system for primary screening
Secondary
screening
area
Conveyor belt leading
to secondary system
Conveyor belt
leading to airplane
If EDS alarms, baggage
is sent to secondary screening
Complexity of conveyor
system will vary
depending on airport
needs and configuration
Baggage
to check-in
Conveyor belt
leading from check-in
to in-line system
FIGURE 11-4 Schematic diagram of in-line baggage screening [8].
475
476
Special Topics in Airpor t Planning and Design
FIGURE 11-5
Stand alone EDS baggage screening equipment.
EDS equipment was initially installed at many airports in terminal
lobbies, next to the check-in counters (Fig. 11-5). Unfortunately, these
stand alone installations added confusion to the congested lobby area
and increased processing times. Airports are now working to move
baggage screening from the lobby area to be part of an in-line
baggage handling system. Guidance for the planning and design
of baggage screening is provided in TSA reports [8].
At small airports, checked baggage is screened by the use of electronic trace detection systems, or manually by TSA screeners.
Employee Identification
TSA regulations require that any person who wishes to access any
portion of an airport’s security identification display area (SIDA)
must display appropriate identification. This identification, typically
known as a SIDA badge, is usually in the form of a laminated credit
card-sized identification with a photograph and name of the badge
holder. Persons requiring a SIDA badge include airport employees,
air carrier employees, concessionaires, contractors, and government
employees such as air traffic controllers, airport security, and others.
Prior to obtaining an identification badge, persons must complete an
application and undergo a fingerprint-based criminal records check.
The SIDA badge must be displayed at all times.
A variety of measures are used at airports to control the access of
employees and vehicles to security sensitive areas. Access to these
areas is provided through the use of a variety of control systems
ranging from simple key locks to smart-access technology. In many
cases, pass codes are calibrated with a person’s SIDA badge and a
Airport Security Planning
person must present his or her badge and proper pass code entry to
gain access to an area.
Advanced identification verification technologies are being developed to enhance access control at airports. One area of new technologies
is biometrics in which human body characteristics, such as fingerprints,
eye retinas and irises, voice patterns, facial patterns, and hand measurements are being used for identification authentication purposes. Biometric devices typically consist of a reader or scanning device, software
that converts the scanned information into a digital format, and a database that stores the biometric information for comparison.
Perimeter Security
An important part of an airport security plan is its strategy for protecting the airport’s perimeter—the area between secured and unsecured areas. The most common methods for securing the airport’s
perimeter are perimeter fencing, controlled access gates, area lighting, and patrolling of the secured area.
Perimeter fencing is the most common method of creating a barrier
around the airport. Fencing can vary in design, height, and type,
depending on local security needs. In the United States, standards for
perimeter fencing are presented in Advisory Circular 107-1, Aviation
Security—Airports.
Controlled access gates provide locations for persons and vehicles
to enter the secured area of the airport. The number of access points
surrounding an airport’s perimeter should be limited to the minimum required for safe and efficient operations of the airport. Controlled access gates typically use some form of controlled access
mechanism, ranging from simple key entry or combination locks, to
advanced identification authentication machines. Some controlled
access gates may be manned by security personnel.
Security lighting is located in and around heavy traffic areas, aircraft service areas, and aircraft operations and maintenance areas at
most airports. Security lighting systems will depend on the local situation and the areas to be protected, but typically they help as a deterrent to criminals and terrorists.
Patrolling by airport operations staff and local law enforcement
will enhance airport perimeter security. Patrols are usually performed
on a routine basis. In addition, most air traffic control towers are situated so that they provide an optimal view of the entire airfield and air
traffic controllers can spot potential security threats.
Vulnerability Assessment
An airport vulnerability assessment is an important tool in determining the extent to which an airport facility may require security
enhancements and serves to introduce security considerations early
in the design process rather than as a more expensive retrofit.
477
478
Special Topics in Airpor t Planning and Design
Threats and vulnerabilities cover a wide range of events, none of
which can be totally eliminated while still operating the system. Since
no system can be totally secure, once threats and vulnerabilities are
identified, their impact on the total system must be assessed to determine whether the risk of a particular danger, and the extent to which
corrective measures can eliminate or reduce its severity. Security is a
process of risk assessment, identifying major threats and considering
how vulnerable the system might be. There are several vulnerability
assessment tools and methodologies available from government and
private organizations.
The threat and vulnerability assessment process is conceptually
diagrammed in Fig. 11-6 for a transportation system. These assessments typically use a combination of quantitative and qualitative
techniques to identify security requirements, including historical
analysis of past events, intelligence assessments, physical surveys,
Issues To Consider:
Surrounding terrain and adjacent structures
Site layout and elements, including perimeter and parking
Location and access to incoming utilities
Circulation patterns and spatial arrangements
Location of higher risk assets within a facility
Mail-handling protocols and procedures
Access controls for service and maintenance personnel
Information technology (IT) controls
Blast resistance and HVAC protection
Vulnerabilities (Likelihood of Occurrence):
*Frequent: Event Will Occur
*Probable: Expect Event to Occur
*Occasional: Circumstances Expected for that
Event; It May or May Not Occur
*Remote:
Possible But Unlikely
*Improbable: Event Will Not Occur
Severity
CRITICAL ASSETS:
Stations, shops, HQs building
Tunnels, bridges, trackwork
Vehicles, command &
control systems
Critical Personnel, passengers
Information systems
Likelihood
SCENARIOS
CatasNeglig
trophic Critical Marginal -ible
Frequent
High
High
Med.
Low
Probable
High
High
Med.
Low
Occasional
High
Med.
Low
Remote
Med.
Low
Low
Improbable
Low
Low
Low
Threats:
Explosives
Incendiary Materials
Chemical agents
Biological agents
Radiological agents
Nuclear agents
Ballistic attacks
Cyber attacks
Insider threat/Sabotage
FIGURE 11-6
IMPACT
(SEVERITY OF OCCURRENCE):
*Catastrophic:
*Critical:
*Marginal:
*Negligible:
Disastrous Event
Survivable but Costly
Relatively Inconsequential
Limited or No Impact
COUNTERMEASURES:
Design
Security technology
Warming devices
Procedures and training
Personnel
Planning, exercising
Model for assessing vulnerabilities for a transportation system [8].
Airport Security Planning
and expert evaluation. When the risk of hostile acts is greater, these
analysis methods may draw more heavily on information from intelligence and law enforcement agencies regarding the capabilities and
intentions of the aggressors.
Assessments typically include five elements:
1. Asset analysis
2. Target or threat identification
3. Vulnerability assessment
4. Consequence analysis or scenarios
5. Countermeasure recommendations
Assert analysis is an inventory of all airport facilities, operating
and maintenance procedures, vehicles, employees, power systems,
information systems, and computer network configurations. In
reviewing assets, they must be prioritized to determine which assets
may require higher or special protection from attack. In making this
determination, the airport will consider:
• The value of the asset, including current and replacement
value.
• The value of the asset to a potential adversary.
• Where the asset is located and how, when, and by whom an
asset is accessed and used.
• If the asset is lost, what is the impact on passengers, employees,
public safety organizations, the general public, and airport
operations.
A threat is any action with the potential to cause harm. Threat
analysis defines the threats against a facility by evaluating the intent,
motivation, and possible tactics of those who may carry out the
hostile action. The process involves gathering historical data about
hostile events and evaluates which information is relevant in assessing the threats against the facility. Some of the questions that are
addressed include
• What factors about the system invite hostile action?
• How conspicuous is the transportation facility?
• What political event may generate new hostilities?
• Have similar facilities been targets in the past?
Vulnerability is anything that can be taken advantage of to carry
out a threat. This includes vulnerabilities in the design and construction of the facility, operations, administration, and management procedures. Vulnerability analysis identifies specific weaknesses and
479
480
Special Topics in Airpor t Planning and Design
how hostile actions may occur. Vulnerabilities are usually prioritized
through the development of scenarios that pair assets and threats.
Using these scenarios, airports can evaluate the effectiveness of their
current policies, procedures, and physical protection capabilities to
address the consequences.
Scenario analysis requires a methodology that encourages roleplaying by airport personnel, emergency responders, contractors,
and others to brainstorm ways to attack the airport. By matching
threats to critical assets, the airport can identify the capabilities
required to support specific types of attacks. For each scenario, consequences are assessed both in terms of severity of impact and probability of loss for a given threat.
Examples of vulnerabilities that may be identified from scenario
analysis include the following:
• Accessibility of surrounding terrain and adjacent structures
to unauthorized access
• Site layout and elements
• Location and access to utilities
• Building construction with respect to blast resistance
• Sufficiency of lighting, locking controls, alarm systems, venting
systems, and facility support control
• Information technology and computer network ease-ofpenetration
At the conclusion of the scenario analysis step, the airport will
have a list of vulnerabilities for its critical assets. These vulnerabilities
will be documented in a confidential report that may be organized as
follows:
• Deficiencies in planning
• Deficiencies in the coordination with local emergency
responders
• Deficiencies in training
• Deficiencies in physical security—access control, surveillance,
blast mitigation, chemical, biological, or radioactive agent
protection
Based on the results of the scenario analysis, the airport will identify countermeasures to reduce the vulnerabilities. These actions may
be grouped into two general categories:
1. Physical protective measures designed to reduce system asset
vulnerability to explosives, ballistics attacks, cyber attacks,
and the release of chemical, biological, radiological, or nuclear
agents
Airport Security Planning
2. Procedural security measures including procedures to detect,
mitigate, and respond to an act of terrorism or extreme
violence
Security at General Aviation Airports
Airport security has undergone significant changes over the past 5
years. Regulations, procedures, and the application of new technologies have focused on commercial service airports. However, the TSA
mandate is to examine security requirements for all aspects of the
transportation system, but to date they have not required general
aviation (GA) airports to implement security measures except for
three general aviation airports in the Washington, D.C. area. Following the events of September 11, 2001, several aviation groups began
work to develop security guidelines for general aviation airports. The
Aircraft Owners and Pilots Association (AOPA), state governments,
and others prepared guidelines to assist airport managers and the
TSA published Security Guidelines for General Aviation Airports [11] in
2004. The purpose of the TSA document is to provide owners, operators, sponsors, and other entities charged with oversight of general
aviation airports with a set of federally endorsed security best practices and methods for determining when and where these measures
may be appropriate. Recognizing the every general aviation airport is
unique, TSA has not yet implemented national regulations for GA
airport security. The GA industry has developed several security initiatives including awareness programs, reporting methods, and educational courses, and many airports have prepared security plans
using principles developed for commercial service airports. Among
the security measures taken at general aviation airports include
• Personnel, visitor, aircraft, and vehicle identification
procedures
• Perimeter fencing
• Controlled access gates
• Security lighting
• Locks and key control
• Patrolling
Future Security
Protecting airports and aviation against future threats is an imperfect
science and, as a result, future airport security will always be an
unknown. Concerns for the safe, secure, and efficient travel of passengers and cargo will always be a top priority in civil aviation, and
every effort will be taken to make the system as secure as possible for
481
482
Special Topics in Airpor t Planning and Design
the foreseeable future, and one must anticipate changes in regulations, security requirements, and technologies. Security planning and
assessment is a continuing process at every airport.
References
1. Airport Development Reference Manual, 9th ed., International Air Transport
Association, Montreal, Canada, 2004.
2. Airport Operations, 2d ed., Norman Ashford, H. P. Martin Stanton, and Clifton
A. Moore, McGraw-Hill, New York, 1997.
3. Airport Planning and Management, 5th ed., Alexander T. Wells and Seth B. Young,
McGraw-Hill, New York, 2004.
4. Aviation Security—Airports, U.S. DOT Federal Aviation Administration,
Advisory Circular 107-1, Washington, D.C., 1972.
5. Airport Services Manual, Part 7—Airport Emergency Planning, 2d ed., International
Civil Aviation Organization, Montreal, Canada, 1991.
6. General Aviation Safety and Security Practices, Craig Williams, Airport
Cooperative Research Program (ACRP) Synthesis 3, Transportation Research
Board, Washington, D.C., 2007.
7. “A New Approach to Airport Security,” Sal DePasquale, Proceedings of the 24th
International Air Transportation Conference, Louisville, Ky., American Society
of Civil Engineers, 1996.
8. Planning Guidelines and Design Standards for Checked Baggage Inspection Systems,
Transportation Security Administration, Washington, D.C., 2007.
9. Recommended Security Guidelines for Airport Planning, Design and Construction,
Transportation Security Administration, Washington, D.C., 2006.
10. Security, 8th ed., Annex 17, International Civil Aviation Organization, Montreal,
Canada, 2006.
11. Security Guidelines for General Aviation Airports, Transportation Security
Administration, Report A-001, Washington, D.C., 2004.
CHAPTER
12
Airport Airside
Capacity and Delay
Introduction
In air transportation, particular concern is focused upon the movement of aircraft, passengers, ground access vehicles, and cargo
through both the airport and aviation system. The experienced air
traveler has grown accustomed to delayed flights, overbooking,
missed connections, ground congestion, parking shortages, and long
lines in the terminal building during peak travel periods. For many
air transportation trips, the relative advantage of the speed characteristics of aircraft is considerably diminished by ground access, terminal system, and airside delays.
In a more general sense, the unprecedented growth in the demand
for air transportation services over the past 30 years has, in many
situations, outpaced the ability to provide facilities to adequately
accommodate this growth. To a greater extent, elements of the air
transport system are being stressed beyond their design capabilities,
resulting in significant service deterioration at major airports in this
country [5, 6, 9, 10, 18, 21, 27]. It is understandable then that considerable emphasis has been placed upon research to analyze the level and
causes of capacity deficiencies. With the maturation of complex computer-based simulation models based on fundamental theories of
operations research and queuing theory, it is possible, now more than
ever in the history of airport planning and design, to accurately estimate the capability of airport and aviation system components to
process demand and to pinpoint the causes of deficiencies in these
systems. This knowledge allows one to propose solutions to the problems identified.
Information on airport capacity and delay is important to the airport planner. There is a strong belief within the aviation community
that significant gains in air transportation efficiency can be realized
through an understanding of the factors causing delays and by the
application of technological innovations and operational policies to
alleviate delay.
483
484
Special Topics in Airpor t Planning and Design
Planners can compare capacity of an airport system, or any of its
components, with the existing and forecast demand and ascertain
whether improvements to increase capacity will be needed. Comparing
the capacity of different configurations at airfields helps determine
which are the most efficient. Inadequate capacity leads to increasing
delays at airports. Delay is an important factor in a benefit-cost analysis and if an economic value can be placed on delay, the delay reduction savings resulting from an improvement become benefits which
can be used to justify the cost of that improvement [19].
Capacity and Delay Defined
The term capacity is used to designate the processing capability of a
service facility over some period of time, typically defined as the
maximum number of operations that a service facility can accommodate over a defined period of time. For a service facility to realize its
maximum or ultimate capacity there must be a continuous demand
for service. In the field of aviation, levels of demand that exceed the
capacity at a given component of an airport or airspace result in
system delays, where delay may be defined as the increase in time
required to perform an operation from “normal” nondelayed operations. Additional time required may come in the form of queuing,
or waiting, to perform an operation, or a reduction in speed due to
congestion. An operation on the airfield is often defined as a takeoff
or a landing, while in the terminal an operation may be the processing of a passenger through the terminal. In the airspace, an operation may be considered an aircraft traveling through a certain sector
of airspace.
However, the periods of time that demand levels exist to create
delays has steadily increased, particularly since the beginning of the
twenty-first century. It is this increase in demand to levels that near or
exceed capacity over longer periods of time that result in system
delays that cause a deterioration in service quality rendering the performance of the aviation system increasingly undesirable. Therefore,
airport planners and designers are faced with the problem of providing sufficient capacity to accommodate fluctuating demand with an
acceptable level or quality of service. Typically, the design specifications at an airport require that sufficient capacity be provided so that
a relatively high percentage of the demand will be subjected to some
minimal amount of delay.
To provide sufficient capacity to service a varying demand without delay will normally require facilities which are difficult to economically justify. Therefore, in design, a level of delay acceptable
from the perspectives of both the user and the operator is usually
established and system components of sufficient capacity are chosen
to ensure that these delay criteria are met.
Airport Airside Capacity and Delay
Capacity and Delay in Airfield Planning
In airfield planning, capacity and delay studies are performed to
evaluate the ability for an airfield in its current configuration to
accommodate current and future levels of demand. As demand is
forecast to exceed the current airfield’s capacity, airfield planners
consider alternative airfield configurations, designed for additional
capacity, to measure their effect on mitigating potential future
delays.
As the primary objective of capacity and delay studies is to determine effective and efficient means to increase capacity and reduce
delay at airports, analyses are conducted to examine the implications
of the changes in the nature of the demand, the operating configurations of the airfield and the impact of facility modifications on the
quality of service afforded this demand. Some of the typical applications of these analyses might include
1. The effect of alternative runway exit locations and geometry
on runway system capacity
2. The impact of airfield restrictions due to noise abatement
procedures, limited runway capacity, or inadequate airport
navigational aids on aircraft processing rates
3. The consequences of introducing new aircraft into the fleet
mix at an airport, and an examination of alternative mechanisms for servicing the mix
4. The investigation of alternative runway-use configurations
on the ability to process aircraft
5. The generation of alternatives for new runway or taxiway
construction to facilitate aircraft processing
6. The gains which might be realized in system capacity or delay
reduction by the diversion of general aviation aircraft to
reliever facilities in large air traffic hub areas
According to the United States Government Accountability
Office, between 1998 and 2007, delays and cancellations for United
States commercial aviation increased by 62 percent, while the number
of operations increased by only 38 percent. In 2007 alone, more than
2 million of the nation’s 7.5 million annual operations suffered delays
or cancellations. In the busiest of regions, such as the New York metropolitan area, delays and cancellations have increased by more than
110 percent, while the number of operations increased by less than
60 percent [31]. Figure 12-1 illustrates the increasing trend of delayed
and cancelled operations system wide since 1998.
Delays have also gotten more severe. In 2007, the average length
of a flight delay was 56 min, compared to 49 min in 1998. More than
64,000 operations were delayed by more than 3 h in 2007.
485
486
Special Topics in Airpor t Planning and Design
30
Percentage of flights
25
20
15
10
5
0
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Year
Canceled flights
Late arrivals
Source: DOT.
FIGURE 12-1 Trends in percentage of late arriving and canceled flights—U.S.
system-wide (U.S. Government Accountability Office).
The distribution of the causes of delays greater than 15 min are
given in Fig. 12-2 for the year 2007, as reported by the U.S. Department of Transportation (DOT).
The operational and economic implications of delay to aircraft
increasingly dictate that delay analyses be included in airfield planning studies and that these analyses be conducted well before demand
is expected to reach capacity levels.
Approaches to the Analysis of Capacity and Delay
In this chapter, analysis of capacity and delay is confined to the airfield, or aircraft operations area, which is composed of the runways,
taxiways, and apron areas. It should be noted that the variations of
the principles and tools described in this chapter may also be
applied to determining capacity and delay in the airport terminal,
as well.
While studies of capacity and delay are most often evaluated by
the use of analytical and computer simulation models, the focus of
this chapter first is on analytical models, often referred to as mathematical models, which form the basis for more complex computer
simulation models.
Airport Airside Capacity and Delay
0.2%
Security
Extreme weather
6%
38%
28%
29%
National Aviation System
Airline
Late arriving aircraft
Source: DOT.
Note: Total may not add up to 100 percent due to rounding.
FIGURE 12-2
DOT reported sources of delay, United States, 2007.
Mathematical models of airport operations are tools for understanding the important parameters that influence the operation of
systems and investigating specific interactions in systems that are of
particular interest. Depending upon the complexity of the system,
several conditions may be studied, perhaps more cheaply and quickly
than by other methods. To make the mathematics tractable for a complex system, many simplifying assumptions must often be made
which may result in unrealistic results. In such a case, one can resort
to a computer simulation model or some other technique. Thus it is
necessary, when contemplating the formulation and application of a
mathematical model, to examine critically the correspondence
between the real world being studied and the abstract world of the
model and to determine the effect of their differences on the decisions
to be made.
For airport planning, airfield capacity has been defined in two
ways. One definition which has been used extensively in the United
States in the past is that capacity is the number of aircraft operations during a specified interval of time corresponding to a tolerable
level of average delay. This is shown in Fig. 12-3 and is referred to as
practical capacity. This definition has traditionally been suggested
by the Federal Aviation Administration to give rudimentary estimates of delay as a function of ultimate, or throughput capacity,
which is defined as the maximum number of operations that a service
487
488
Special Topics in Airpor t Planning and Design
Increase
Practical
Capacity
Throughout
Capacity
Congestive Delay
(Typical 9 minutes)
AVERAGE
DELAY
(minutes)
Maximum Acceptable Delay
(Typical 4 minutes)
0
Increase
DEMAND (Number of Operations)
FIGURE 12-3 Delay as a function of capacity and demand.
facility can accommodate over a defined period of time and is also
illustrated in Fig. 12-3.
An important difference in these two measures of capacity is that
one is defined in terms of delay and the other is not. There are several
reasons for considering two definitions of capacity. There has been a
general lack of agreement on the specification of acceptable levels of
delay applicable to all airports and their airfield components. Because
policies, expectations, and constraints differ from airport to airport,
the amount of acceptable delay differs from airport to airport. The
definition of ultimate capacity does not include delay and reflects the
capability of the airfield to accommodate aircraft during peak periods of activity. However, for this definition one does not have an
explicit measure of the magnitude of congestion and delay. The magnitude of delay is greatly influenced by the pattern of demand. As an
example, when several aircraft wish to use the airfield at the same
time, the delay will naturally be larger than if these aircraft were
spaced at some interval of time apart. Since the fluctuation of demand
within any hour can vary widely, there may be large variations in
average delay for the same level of hourly aircraft demand. The shape
of the curve in Fig. 12-3 is therefore influenced by the pattern of
demand.
Experience has shown that the definition related to ultimate
capacity yields values that are slightly larger than the definition
which includes delay but the difference is not large. Mathematically,
the analysis of ultimate capacity is less complex than that for practical
capacity, since the determination of practical capacity implies a definition of the acceptable level of delay.
Airport Airside Capacity and Delay
Factors That Affect Airfield Capacity
There are many factors that influence the capacity of an airfield. In
general, capacity depends on the configuration of the airfield, the
environment in which aircraft operate, the type and performance
characteristics of the aircraft operating on the airfield, the availability
and sophistication of aids to navigation, and air traffic control facilities and procedures. A listing of the most important factors includes
1. The configuration, number, spacing, and orientation of the
runway system
2. The configuration, number, and location of taxiways and runway exits
3. The arrangement, size, and number of gates in the apron
area
4. The runway occupancy time for arriving and departing
aircraft
5. The size and mix of aircraft using the facilities
6. Weather, particularly visibility and ceiling, since air traffic
rules in good weather are different than in poor weather
7. Wind conditions which may preclude the use of all available
runways by all aircraft
8. Noise abatement procedures which may limit the type and
timing of operations on the available runways
9. Within the constraints of wind and noise abatement, the
strategy which air traffic controllers choose to operate the
runway system
10. The number of arrivals relative to the number of departures
11. The number and frequency of touch and go operations by
general aviation aircraft
12. The existence and frequency of occurrence of wake vortices
which require greater separations when a light aircraft follows a heavy aircraft than when a heavy follows a light
aircraft
13. The existence and nature of navigational aids
14. The availability and structure of airspace for establishing
arrival and departure routes
15. The nature and extent of the air traffic control facilities
The most significant factor which affects runway capacity is the
spacing between successive aircraft. This spacing is dependent on the
appropriate air traffic rules, which are, to a large extent, functions of
weather conditions and aircraft size and mix.
489
490
Special Topics in Airpor t Planning and Design
Formulation of Runway Capacity through
Mathematical Theory
In l960, the FAA contracted with Airborne Instruments Laboratory to
develop mathematical models for estimating runway capacity [3].
These models relied on steady-state queuing theory. Essentially there
were two models, one for runways serving either arrivals or departures and the other for runways serving mixed operations. For runways used exclusively for arrivals or departures the model was that
of a simple Poisson type queue with a first come, first served service
discipline. The demand process for arrivals or departures was characterized as a Poisson distribution with a specified mean arrival or
departure rate. The runway service process was a general service distribution specified by the mean service time and the standard deviation of the mean service time. For mixed operations, when runways
are used for both takeoffs and landings, the process is more complicated, and a preemptive spaced arrivals model was developed. In
this model, arrivals have priority over departures for the use of the
runways. The takeoff demand process was assumed to follow a Poisson distribution; however, the landing process encountered at the
end of the runway is not Poisson but more like the output of an airborne queuing system.
It was recognized that steady-state conditions are rarely achieved
at airports; however, it was argued that time-dependent solutions,
although possible, were quite complex and were out of the question
for the large number of situations required for the preparation of a
runway capacity handbook to be used by airport planning and design
professionals. Additional support for the use of steady-state solutions
came from observations which showed that average delay times
yielded by the models were in general agreement with measured
delays under a wide variety of operating conditions.
Mathematical Formulation of Delay
The calculation of delay for runways used exclusively by arrivals was
computed from Eq. (12-1):
Wa =
λ a (σ 2a + 1/µ 2a )
2(1 − λ a /µ a )
(12-1)
where Wa = mean delay to arriving aircraft
λa = mean arrival rate of aircraft
µa = mean service rate for arrivals or the reciprocal of the mean
service time
σa = standard deviation of the mean service time of the arriving
aircraft
Airport Airside Capacity and Delay
The mean service time may be the runway occupancy time or the
time separation in the air immediately adjacent to the runway threshold, whichever value is the larger.
The model for departures is identical to arrivals except for a
change in subscripts. Equation (12-2) is therefore used for the departure delay:
Wd =
λ d (σ d2 + 1/μ 2d)
2(1 − λ d /μ d )
(12-2)
where Wd = mean delay to departing aircraft
λd = mean departure rate of aircraft
µd = mean service rate for departures, or the reciprocal of the
mean service time for departures
σd = standard deviation of the mean service time of the departing aircraft
For mixed operations, arriving aircraft are normally given priority
and the delay to these aircraft is given by the arrivals of Eq. (12-2).
However, the average delay to departures in this situation can be
found from Eq. (12-3):
Wd =
(
) + g (σ + f )
2 (1 − λ )
2 (1 − λ )
λd σ 2j + j 2
j
d
2
f
2
f
a
(12-3)
where Wd = mean delay to departing aircraft
λa = mean arrival rate of aircraft
λd = mean departure rate of aircraft
j = mean interval of time between two successive departures
σj = standard deviation of the mean interval of time between
successive departures
g = mean rate at which gaps between successive arrivals
occur
f = mean value of the interval of time within which no
departure can be released
σf = standard deviation of the interval of time in which no
departure may be released
During busy periods the second term in Eq. (12-3) would be
expected to be zero if it is assumed that aircraft are in a queue at the
end of the runway and are always ready to go when permission is
granted. It must be emphasized that the above equations are only
valid when the mean arrival or departure rate is less than the mean
service rate which is the condition for which the equations have been
derived. The use of the model for the arrivals-only case is illustrated
in Example Problem 12-1.
491
492
Special Topics in Airpor t Planning and Design
Example Problem 12-1 It is necessary to compute the average delay to arriving
aircraft on a runway system which services only arrivals if the mean service time
is 60 s per aircraft with a standard deviation in the mean service time of 12 s and
the average rate of arrivals is 45 aircraft per hour.
The mean service rate for arrivals μa is the reciprocal of the mean service
time yielding 1 aircraft per minute of 60 aircraft per hour. Substitution into
Eq. (12-1) yields
45 ⎡⎣(12 3600) + 1 / 602 ⎤⎦
2
Wa =
2 (1 − 45 60)
= 0 . 026 h = 1 . 6 min
Therefore, the average aircraft delay is about 1.6 min per arrival.
The relationship between delay and capacity can be shown by determining
the runway service rate which corresponds to a delay of 4 min using the above
equation. Assuming that the standard deviation of the mean service time is the
same, we have
)
2
45 ⎡⎣(12 3600 + 1 / μ 2a ⎤⎦
4
=
60
2(1 − 45 / μ a )
or μa is equal to 52 arrivals per hour. If the delay criterion was that arrival delays
could not exceed 4 min then the runway capacity related to delay would be
52 arrivals per hour.
It should be observed that an increase in capacity from 52 to 60 arrivals per
hour, a 15 percent increase in capacity, results in a delay reduction of 2.4 min, a
60 percent reduction in delay. This is typical at airports nearing saturation. Small
increases in capacity can result in significant decreases in delay.
Formulation of Runway Capacity through
the Time-Space Concept
The various intervals of time included in the above models are shown
on the time-space diagram in Fig. 12-4. The time-space diagram is a
very useful device for understanding the sequencing of aircraft operations on a runway system and in the adjacent airspace (Fig. 12-4).
Three arrivals and three departures are serviced.
The basic sequencing rules to service these aircraft are
1. Two aircraft may not conduct an operation on the runway at
the same time.
2. Arriving aircraft have a priority in the use of the runway over
departing aircraft.
3. Departures may be released if the runway is clear and the
subsequent arrival is at least a certain distance from the runway threshold.
Examination of the time-space diagram in Fig. 12-4 shows that
the mean departure interval j is the average of the interval of time
Airport Airside Capacity and Delay
Jpq
Jqr
p
δd
q
l
r
m
n
γ
Fn
Fm
Glm
FIGURE 12-4
Gmn
Time-space diagram concepts for mixed operations on runway system.
between successive departures Jpq and Jqr. Also, the mean time interval between arrivals, the gap between arrivals Ig during which it may
be possible to release g departures—is the average of the quantities
Glm and Gmn. Finally, the value of the interval of time in which departures cannot be released f is equal to the average of the quantities Fm
and Fn.
Several other observations may be made about the sequence of
operations shown on this time-space diagram. The initial departure p
could have been released, if it was available, before the first arrival l
reached the distance δd from the runway threshold since the runway
was clear. The second departure q was released when the previous
departure p cleared the runway, since the next arrival m was more
than distance δd from the threshold at that point in time. However, the
third departure r was not released when that departure cleared the runway because the approaching aircraft m was closer than distance δd
from the threshold at that point in time. For the same reason, this
departure was not released until after the last arrival n cleared the
runway. In this figure, the delays which would occur to aircraft are
due to the required separations between different types of operational
sequences.
The use of the air traffic separation rules is accommodating a
series of arrivals and departures may be best understood through a
numerical example problem illustrating the time-space concept for
processing aircraft on a runway system.
493
494
Special Topics in Airpor t Planning and Design
Example Problem 12-2 A runway is to service arrivals and departures. The
common approach path is 7 mi long for all aircraft. During a particular interval of time the runway is serving only two types of aircraft, a type A with an
approach speed of 120 mi/h and a type B with an approach speed of 90 mi/h.
Each arriving aircraft will be on the runway for 40 s before exiting the runway.
The air traffic separation rules in effect are given in Table 12-1.
During the period of time to be analyzed five aircraft in an ordered arrival
queue of a B, A, A, B, and A aircraft approach the runway. An identical ordered
departure queue of aircraft is awaiting clearance to takeoff.
A time-space diagram to service these aircraft will be drawn assuming the first
arrival is at the entry gate at time 0 and arrivals are given priority over departures.
The time-space diagram for arrivals is drawn first since these aircraft normally have priority over departures. This is shown on Fig. 12-5. The dashed lines
indicate points where the interarrival separation rules are enforced to ensure
the minimum interarrival spacing is maintained. The numbers in parentheses
indicate the time each aircraft is at the point indicated.
Operational Sequence
Air Traffic Rules
Arrival–departure
Clear runway
Departure–arrival
Arrival at least 2 mi from arrival threshold
Departure–departure
120 s
Arrival–arrival
Miles:
Lead
A
Trailing
TABLE 12-1
0
100
⎡4
⎢
B ⎢⎣5
A
B
3⎤
⎥
3⎥⎦
Air Traffic Separation Rules for Example Problem 12-2
200
300
400
500
600
700
800
900
1000
Time
(seconds)
Exit
(280) (370)
Threshold
(490)
(710) (800)
1
3 miles
3 miles
2
4 miles (430)
3
4
B
A
A
5
6
Entry
7
Gate
(160)
(280)
A
5 miles B
(430)
(590)
Distance
(miles)
FIGURE 12-5 Time-space diagram for scheduling arrivals in Example Problem 12-2.
Airport Airside Capacity and Delay
Since the first aircraft, a type B aircraft, is at the entry gate at time 0 and
it takes 280 s to travel the common approach path from the entry gate to the
runway threshold, this aircraft passes over the runway threshold at time 280 s.
Immediately behind this aircraft is a type A aircraft which is approaching the
runway at a speed of 120 mi/h. In this case, the trailing aircraft A is flying
faster than the leading aircraft B and, therefore, it is closing in on the leading
aircraft. These two aircraft are closest together when the leading aircraft passes
over the arrival threshold or at time 280 s. At this time the trailing aircraft can
be scheduled no closer than 3 mi behind the leading aircraft or the trailing
aircraft is scheduled to pass over the 3-mi point at time 280 s. Since this aircraft
is approaching the runway at a rate of 30 s/mi, it passes over the runway
threshold 90 s later or at time 370 s. It passes over the entry gate 210 s earlier
or at time 160 s.
This process is continued until all aircraft have been scheduled. It should be
observed that when a type B aircraft is trailing a type A aircraft, since the type B
is traveling at a speed less than the type A, these two aircraft are closest together
when the trailing aircraft passes over the entry gate and the required separation
is maintained at that point.
Once all the aircraft are scheduled as shown in Fig. 12-5, it is determined
that it will take 800 s to service these five arriving aircraft. The time span at the
runway threshold for serving these five arrivals is 800 − 280 = 520 s. In this time
span there are four pairs of arrivals. Therefore, the average time between arrivals,
the interarrival time, is 520 divided by 4 or 130 s per arrival. The capacity of the
runway to service arrivals will be shown later to be
Ca =
3600
= 28 aircraft per hour
130
The time-space diagram in Fig. 12-6 is then constructed from that in Fig. 12-5
and is used to determine if a departure may be released in the time gaps
between arrivals. Each arrival spends 40 s on the runway prior to exiting the
0
100
200
300
(320)
Exit
400
500
(410)
700
(530)
Threshold
(120)
600
800
900
1000
Time
(seconds)
(750) (840)
(530) (650)
(240)
1
Two Mile 2
Point For
Departure 3
Clearance 4
(200) (310)
(430)
(630) (740)
5
6
Entry
7
Gate
Distance
(miles)
FIGURE 12-6 Time-space diagram for scheduling mixed operations in Example
Problem 12-2.
495
496
Special Topics in Airpor t Planning and Design
Ri
Ti
γ
Entry
gate
Vi
Tj
δij
δij
Vj
Vj
FIGURE 12-7 Time-space diagram for error-free interarrival spacing for the
closing case when Vi ≤ Vj .
runway. Therefore, the time when each arriving aircraft exits the runway is
determined first. The results are shown in Fig. 12-6. At any time, if the runway
is clear, a departure may be cleared for takeoff if the incoming arrival is at least
2 mi from the arrival threshold and it has been at least 120 s since the last departure was cleared for takeoff.
Again, in Fig. 12-7, the dashed lines indicate points where the separation
rules are enforced and the numbers in parentheses indicate the time each aircraft
is at the point indicated. However, these comparisons are now made to ensure
that the departure-departure, arrival-departure, and departure-arrival spacings
are each maintained.
It is seen that it will take 840 s, measured at the runway threshold, to
service all of the arrivals and all of the departures. It is also observed that
departures can only be inserted between a pair of arrivals on two occasions.
Therefore, the probability of inserting a departure between the 4 pairs of
arrivals is 2 out of 4, or 0.50. The capacity to service mixed operations will be
shown later to be
Cm =
3600
(1 . 0 + 0 . 50) = 42 aircraft per hour
130
Airport Airside Capacity and Delay
where 1.0 represents the probability of an arrival at the threshold every 130 s
and 0.50 represents the probability of inserting a departure in an interarrival
time of 130 s.
The capacity of the runway to service departures only will be shown
later to be
Cd =
3600
= 30 aircraft per hour
120
Formulation of Ultimate Capacity
Capacity as defined here expresses the maximum physical capability
of a runway system to process aircraft. It is the ultimate capacity or
maximum aircraft operations rate for a set of specified conditions and
it is independent of the level of average aircraft delay. In fact, it has
been shown that when traffic volumes reach hourly capacity levels
average aircraft delays may range from 2 to 10 min.
Delay is dependent on the capacity as well as the magnitude,
nature, and pattern of demand. Delays can occur even when the
demand averaged over 1 h is less than the hourly capacity. Such
delays occur because demand fluctuates within an hour so that,
during some smaller intervals of time, demand is greater than the
capacity.
If the magnitude, nature, and pattern of demand are fixed, then
delay can be reduced only by increasing capacity. On the other hand,
if demand can be manipulated to produce more uniform patterns of
demand, then delay can be reduced without increasing capacity.
Thus, estimating capacity is an integral step in determining delay
to aircraft.
Mathematical Formulation of Ultimate Capacity
These types of models determine the maximum number of aircraft
operations that a runway system can accommodate in a specified
interval of time when there is continuous demand for service [26].
In these models capacity is equal to the inverse of a weighted average
service time of all aircraft being served. For example, if the weighted
average service time is 90 s, the capacity of the runway is 1 operation every 90 s or 40 operations per hour. Models treat the common
approach path to the runway together with the runway as the runway system. The runway service time is defined as either the separation in the air between arrivals in terms of time, the interarrival
time, or the runway occupancy time, whichever is the largest. The
material presented in this section is taken largely from several
references [16, 25, 26].
497
498
Special Topics in Airpor t Planning and Design
Development of Models for Arrivals Only
The capacity of a runway system used only for arriving aircraft is
influenced by the following factors:
1. The aircraft mix which is usually characterized by segregating aircraft into several classes according to their approach
speeds
2. The approach speeds of the various classes of aircraft
3. The length of the common approach path from the entry gate
to the runway threshold
4. The minimum air traffic separation rules or the practical
observed separations if no rules apply
5. The magnitude of errors in arrival time at the entry point to
the common approach path, the entry gate, and speed variation of aircraft on the common approach path
6. The specified probability of violation of the minimum air
traffic separations considered acceptable or attainable
7. The mean runway occupancy times of the various classes of
aircraft in the mix and the magnitude of the variation in these
times
The Error-Free Case
With little loss in accuracy and to make the computations simpler,
aircraft are grouped into several discrete speed classes Vk. To obtain
the weighted service time for arrivals, it is necessary to formulate a
matrix of the intervals of time between aircraft arrivals at the runway
threshold. Having this matrix and the percentage of the various
classes in the aircraft mix, the weighted service time can be computed.
The inverse of the weighted service time is the capacity of the
runway.
Let the error-free matrix be designated as [Mij], which is made up
of the elements mij, the minimum error-free time interval at the runway threshold for aircraft of speed class i followed by aircraft of class j,
the percentage of aircraft of class i in the mix pi, and the percentage of
aircraft of class j in the mix pj. Then
ΔTij = Tj − Ti = mij
(12-4)
where ΔTij = actual time separation at the runway threshold for two
successive arrivals, an aircraft of speed class i followed
by an aircraft of speed class j
Ti = time that the leading aircraft i passes over the runway
threshold
Airport Airside Capacity and Delay
Tj = time that the trailing aircraft j passes over the runway
threshold
mij = minimum error-free interarrival separation at the runway threshold which is the same as ΔTij in the errorfree case
E(ΔTij) = ∑pijmij = ∑[pij][Mij]
(12-5)
where E(ΔTij) = expected value of the service time, or interarrival
time, at the runway threshold for the arrival aircraft
mix
pij = probability that the leading arriving aircraft i will be
followed by the trailing arriving aircraft j
[pij] = matrix of these probabilities
[Mij] = matrix of the minimum interarrival separations mij
The capacity for arrivals is given by
Ca =
1
E(ΔTij )
(12-6)
where Ca is the capacity of the runway to process this mix of arrivals.
To obtain the interarrival time at the runway threshold, it is necessary to know whether the speed of the leading aircraft Vi is greater
or less than that of the trailing aircraft Vj, since the separation at the
runway threshold will differ in each case. This can be illustrated by
drawing time-space diagrams representative of these conditions as
shown in Figs. 12-8 and 12-9. In these diagrams the following notation is used:
γ length of the common approach path
δij minimum permissible distance separation between two arriving
aircraft, a leading aircraft i and a trailing aircraft j, anywhere
along the common approach path
Vi approach speed of the leading aircraft i of class k
Vj approach speed of the trailing aircraft j of class k
Ri runway occupancy time of the leading aircraft
The Closing Case (Vi Ä Vj)
First let us consider the case where the leading aircraft’s approach
speed is less than that of the trailing aircraft, as shown in Fig. 12-8.
The minimum time separation at the threshold may be written in
terms of the minimum distance separation δij and the speed of the
trailing aircraft Vj. However, if the runway occupancy time of the
499
500
Special Topics in Airpor t Planning and Design
δij
+γ 1 – 1
Vi
Vj Vi
Ti
Tj
Vi
Vj
γ
δij
Entry gate
FIGURE 12-8 Time-space diagram for error-free interarrival spacing for the
opening case when Vi > Vj for aircraft control from entry gate to arrival
threshold.
Ri
γ
Vi T
i
γ
δij
+γ 1 – 1
Vj
Vj Vi
Tj
Vi
Vj
Entry
gate
δij
FIGURE 12-9 Time-space diagram for error-free interarrival spacing for the
opening case when Vi > Vj for both aircraft separated in vicinity of entry gate.
Airport Airside Capacity and Delay
arrival Ri is greater than the airborne separation, then it would be
the minimum separation at the threshold. The equation for this
case is
ΔTij = Tj − Ti =
δ ij
Vj
(12-7)
The Opening Case (Vi > Vj)
Next let us consider the case where the leading aircraft’s approach
speed Vi is greater than that of the trailing aircraft Vj as shown in
Figs. 12-8 and 12-9, the minimum time separation at the threshold is
written in terms of the distance δij the length of the common
approach path γ and the approach speeds of the leading and trailing
aircraft Vi and Vj. This corresponds to the minimum distance separation δij along the common approach path which now occurs at the
entry gate instead of the threshold. The equation for the case shown
in Fig. 12-8, when control is exercised only from the entry gate to the
arrival threshold is
ΔTij = Tj − Ti =
δ ij
Vi
⎛1
1⎞
+⎜ − ⎟
V
V
⎝ j
i⎠
(12-8)
When control is exercised to maintain the separations between both
aircraft as the leading aircraft passes over the entry gate, as shown in
Fig. 12-10, the equation is
ΔTij = Tj − Ti =
⎛1
1⎞
+⎜ − ⎟
Vj ⎝ Vj Vi ⎠
δ ij
(12-9)
It should be carefully noted that the only difference between Eqs. (12-8)
and (12-9) is in the first term of the equation, where Vi and Vj are
interchanged.
Example Problem 12-3 This problem will solve Example Problem 12-2 using the
error-free analytical equations developed above. It is necessary to determine the
arrival capacity of the runway in an error-free context where aircraft separations
are maintained in the airspace along the common approach path between the
entry gate and the arrival threshold.
There are four possible interarrival cases, a leading A and a trailing A, a
leading B and a trailing B, a leading A and a trailing B, and a leading B and a
trailing A. These cases are governed by Eqs. (12-7) and (12-8). Equation (12-7)
gives the minimum time between arrivals at the runway threshold when the
leading aircraft is approaching the runway at an approach speed less than or
equal to the approach speed of the trailing aircraft.
501
502
Special Topics in Airpor t Planning and Design
If we have a leading A and a trailing A, or a leading B and a trailing B, both
aircraft are traveling at the same speed. Therefore, Eq. (12-7) applies and we have
for a type A following a type A
ΔTij =
4(3600)
= 120 s
120
and for a type B following a type B
ΔTij =
3(3600)
= 120 s
90
When the leading aircraft is type B and the trailing aircraft is type A,
Eq. (12-7) also applies and we have
ΔTij =
3(3600)
= 90 s
120
When the leading aircraft is approaching the runway at an approach speed
greater than the approach speed of the trailing aircraft, the minimum time
between arrivals at the runway threshold is given by Eq. (12-8). This is the case
when a type B follows a type A aircraft. Therefore, we have
ΔTij =
⎛ 1
5(3600)
1 ⎞
(3600) = 220 s
+ 7⎜
−
120
⎝ 90 120⎟⎠
The ordered queue consists of the pairs of arrivals B-A, A-A, A-B, and B-A.
Therefore, we have the following interarrival matrix and probability matrix
based upon the actual queue of arriving aircraft given:
[Tij ] :
Leading
A
Trailing
B
A ⎡120
⎢
B ⎢⎣220
[ pij ] :
90⎤
⎥
120⎥⎦
Leading
A
Trailing
A ⎡0 . 25
⎢
B ⎢⎣0 . 25
B
0 . 50⎤
⎥
0 . 00⎥⎦
From Eq. (12-5), since in the error-free case [Tij] is equal to [Mij], we have that
the expected value of the interarrival time is
E(ΔTij) = 0.25(120) + 0.50(90) + 0.25(220) + 0.00(120) = 130 s
From Eq. (12-6) for the arrival capacity of the runway we then have
Ca =
3600
= 28 operations per hour
130
This agrees exactly with the results of this problem done by the time-space
diagram method in Example Problem 12-2.
Airport Airside Capacity and Delay
Consideration of Position Error
The above models represent the situation of a perfect system with no
errors. To take care of position errors, a buffer time is added to the
minimum separation time to ensure that the minimum interarrival
separations are maintained. The size of the buffer depends upon the
probability of violation of the minimum separation rules which is
acceptable. Figure 12-10 shows the position of the trailing aircraft as
it approaches the runway threshold. In the top portion of this illustration, the trailing aircraft is sequenced so as its mean position is exactly
determined by the minimum separation between the leading and
trailing aircraft. However, if the aircraft position is a random variable
there is an equal probability that it can be either ahead or behind
schedule.
Naturally if it is ahead of schedule the minimum separation criterion will be violated. If the position error is normally distributed,
then the shaded area of the bell-shaped curve would correspond to a
probability of violation of the minimum separation rule of 50 percent.
Therefore, in order to lower this probability of violation, the aircraft
may be scheduled to arrive at this position later by building in a buffer
to the minimum separation criterion as shown in the bottom portion
of the illustration. In this case, only when the aircraft is so far ahead
Mean position of
trail aircraft
Runway
threshold
Buffer
Minimum spacing
Runway
threshold
Actual separation
Scheduled position of
trail aircraft
Actual position of
lead aircraft
FIGURE 12-10 Illustration of buffer spacing on actual separation between
aircraft when position error is considered.
503
504
Special Topics in Airpor t Planning and Design
of schedule as to encroach upon the smaller shaded area of the bellshaped curve would a separation violation occur. There is of course
less of a probability of this occurring. In practice, air traffic controllers
schedule aircraft with a buffer, as well as to instruct pilots to vary
aircraft speeds, so that the probability of violation of the minimum
separation rules is at an acceptable level.
As will be shown, in the closing case the buffer is a constant value.
However, in the opening case the buffer need not be a constant value
and will normally be less than the buffer for the closing case. Having
the models for the buffer, a matrix of buffer times [Bij] for aircraft of
speed class i followed by aircraft of speed class j is developed. This
matrix is added to the error-free matrix to determine the actual interarrival time matrix from which the capacity may be found. The relationship is given in Eq. (12-10).
E(ΔTij) = ∑[pij][Mij + Bij]
(12-10)
The Closing Case
In this case the leading aircraft’s approach speed is less than that of
the trailing aircraft and the separations are shown in Fig. 12-7. Let us
call ΔTij the actual minimum interval of time between aircraft of class
i and class j, and assume that runway occupancy is less than ΔTij.
Designate the mean or expected value of ΔTij as E(ΔTij) and e0 as a
zero-mean normally distributed random error with a standard deviation of σ0. Then for each pair of arrivals ∆Tij = E(∆Tij) + e0. In order to
not violate the minimum separation rule criteria, the value of ∆Tij
must be increased by a buffer amount bij. Therefore, we have
∆Tij = mij + bij
and also
∆Tij = mij + bij + e0
For this case the minimum separation at the runway threshold is
given by Eq. (12-7). The objective is to find for a specified probability
of violation pv, the required amount of buffer. Thus
δ ij
pv = Prob ∆Tij <
Vj
or
δ ij
δ ij
pv = Prob + bij + e0 <
Vj
Vj
Airport Airside Capacity and Delay
which simplifies to the relationship
pv = Prob(bij < − e0)
Using the assumption that errors are normally distributed with standard deviation σ0, the value of the buffer can be derived as [16]
bij = qvσ0
(12-11)
where qv is the value for which the cumulative standard normal distribution has the value (1 − pv). Stated differently, this simply means
the number of standard deviations from the mean in which a certain
percentage of the area under the normal curve would be found. For
example, if pv = 0.05, then qv is the 95th percentile of the distribution
and equals 1.65. Therefore, in the closing case the buffer time is a
constant that depends on the magnitude of the dispersion of the position error and the acceptable probability of violation pv.
The Opening Case
Next consider the case when the leading aircraft is approaching the
runway threshold at a speed greater than the trailing aircraft. In this
case, the separation between aircraft increases from the entry gate.
The model is premised on the supposition that the trailing aircraft
should be scheduled not less than a distance δij behind the leading
aircraft when the latter is at the entry gate, but it is assumed that strict
separation is enforced by air traffic control only when the trailing aircraft reaches the entry gate. This assumption was shown in Fig. 12-8.
For this case, the probability of violation is simply the probability
that the trailing aircraft will arrive at the entry gate before the leading
aircraft is at a specified distance inside the entry gate. This may be
expressed mathematically as follows:
δ ij + γ
γ
pv = Prob Tj −
< Ti −
Vj
Vi
or
δ ij γ
γ
pv = Prob Tj − Ti <
+ −
Vj Vj Vi
Using Eq. (12-9) with this equation to compute the actual spacing at
the arrival threshold, and simplifying
1
1
bij = σ 0 qv − δ ij −
Vj Vi
(12-12)
505
506
Special Topics in Airpor t Planning and Design
Therefore, for the opening case the amount of buffer is reduced
from that required in the closing case, as shown in Eq. (12-12). Negative values of buffer are not allowed and, therefore, the buffer is some
finite positive number with a minimum of zero. The matrix of the
buffer [Bij] for each pair of aircraft with an interarrival buffer of bij can
then be found. The application of position error to the arrivals only
runway capacity problem is illustrated in Example Problem 12-4.
Example Problem 12-4 Assume that the aircraft approaching the runway in
Example Problem 12-3 have a position error of 20 s which is normally distributed. In this environment the probability of violating the minimum separation
rule for arrival spacing is allowed to be 5 percent.
It is necessary to determine the hourly capacity of the runway to service
arrivals.
The error-free interarrival matrix [Mij] was found earlier and it is only necessary to now find the buffer matrix [Bij] and solve Eq. (12-10) for the expected
value of the interarrival time.
In the closing case where the leading aircraft is slower than the trailing aircraft,
Eq. (12-11) gives the buffer. For a 5 percent probability of violation, qv can be found
from statistics tables as 1.65. For each of these cases, the buffer is independent of
speed and therefore
bij = 20(1.65) = 33 s
In the opening case where the leading aircraft is faster than the trailing aircraft, Eq. (12-12) gives the buffer. Therefore, for Vi = 120 and Vj = 90, we have
bij = 20(1 . 65) − 5 ( 1 90 −
1
) 3600 = −17 s
120
However, the minimum value of the buffer is always 0. Summarizing the
values of bij found for the buffer in a matrix and recalling the [Mij] matrix for the
error-free case, we have
[ Mij ] :
Leading
A
Trailing
B
A ⎡120
⎢
B ⎢⎣220
[Bij ] :
90⎤
⎥
120⎥⎦
Leading
A
Trailing
A ⎡33
⎢
B ⎢⎣ 0
B
33 ⎤
⎥
33⎦⎥
Substitution into Eq. (12-10) then gives the expected value of the interarrival time.
E(ΔTij) = 0.25(153) + 0.50(123) + 0.25(220) = 155 s
and from Eq. (12-6), we have
Ca =
3600
= 23 operations per hour
155
Airport Airside Capacity and Delay
which is a reduction from the arrival capacity found in Example Problem 12-3.
Therefore, one may conclude that the existence of position error reduces the arrival
capacity of a runway.
Development of a Model for Departures Only
Since departures are normally cleared for takeoff based upon maintaining a minimum time interval between successive departures, the
interdeparture time td, the departure-only capacity of a runway Cd, is
given by
Cd =
3600
E(td )
(12-13)
and
E(td) = ∑[pij][td]
(12-14)
where E(td) = expected value of the service time, or interdeparture
time, at the runway threshold for the departure aircraft
mix
[pij] = matrix of the probabilities that the leading departing
aircraft i will be followed by the trailing departing aircraft j
[td] = matrix of the interdeparture times
Development of Models for Mixed Operations
This model is based on the same four operating rules as the model
developed by Airborne Instruments Laboratory [3]. These may be
listed as follows:
Arrivals have priority over departures.
Only one aircraft can occupy the runway at any instant of time.
A departure may not be released if the subsequent arrival is less
than a specified distance from the runway threshold, usually 2 nmi
in IFR conditions.
Successive departures are spaced at a minimum time separation
equal to the departure service time.
A time-space diagram may be drawn to show the sequencing of
mixed operations under the rules stated above and this is done in
Fig. 12-11. In this figure, Ti and Tj are the times that the leading aircraft i and the trailing aircraft j, respectively, pass over the arrival
threshold, δij is the minimum separation between arrivals, T1 is the
time when the arriving aircraft clears the runway, Td is the time when
the departing aircraft begins its takeoff roll, δd is the minimum distance that an arriving aircraft must be from the threshold to release a
departure, T2 is the time which corresponds to the last instant when a
departure can be released, Ri is the runway occupancy time for an
507
508
Special Topics in Airpor t Planning and Design
Ri
Ti
td
T1
Td
T2
Tj
δd
G
Vi
δd
Vj
δij
Vj
FIGURE 12-11 Time-space diagram for error-free interarrival spacing for
mixed operations on a runway system.
arrival, G is the time gap in which a departure may be released, and
td is the required service time for a departure.
Since arrivals are given priority over departures, the arriving aircraft are sequenced at the minimum interarrival separation and a
departure cannot be released unless there is a gap between arrivals G.
Therefore, we may write
G = T2 − T1 ≥ 0
but we know that
T1 = Ti + Ri
and
T2 = Tj −
δd
Vj
Therefore, we may write
δ
T2 − T1 ≥ Tj − d − (Ti + Ri ) ≥ 0
V
j
Airport Airside Capacity and Delay
or to release one departure between a pair of arrivals we have
Tj − Ti ≥ Ri +
δd
Vj
Through a simple extension of this equation it is apparent that the
required mean interarrival time E(∆Tij) to release nd departures
between a pair of arrivals is given by
δ
E(∆Tij ) ≥ E(Ri ) + E d + (nd − 1)E(td )
Vj
(12-15)
It should be noted that the last term of this equation is equal to
zero when only one departure is to be inserted between a pair of
arrivals. An error term may be added on to the above equation, σGqv,
to account for the violation of the gap spacing. The use of Eq. (12-15)
with gap error will be illustrated in Example Problem 12-5.
The capacity for mixed operations is given by the equation
Cm =
where
(
1
1 + ∑ nd pnd
E(∆Tij )
)
(12-16)
Cm = capacity of the runway to process mixed operations
E(∆Tij) = expected value of the interarrival time
nd = number of departures which can be released each gap
between arrivals
pnd = probability of releasing nd departures in each gap
The application of the equations for mixed operations on a runway is
shown in Example Problem 12-6.
Example Problem 12-5 Assume that the aircraft approaching the runway in
Example Problem 12-4 have an error in the gap between arrivals of 30 s which
is normally distributed. In this environment, the probability of violating the
minimum gap in which departures can be released is 10 percent. The runway
occupancy time for a type A aircraft is 50 s and for a type B aircraft is 40 s. A
departure can be released if the arriving aircraft is at least 2 mi from the arrival
threshold. The minimum time between successive departures is 60 s. The arrival
mix and the departure mix are identical.
It is necessary to determine the minimum separation between arrivals in order
to ensure that one departure can be released between each pair of arrivals.
The required interarrival time to release a departure between every pair of
arrivals is given by Eq. (12-15).
There are three type A aircraft and two type B aircraft in both the arrival
and departure queue. Therefore, there is a 60 percent chance of a type A aircraft and a 40 percent chance of a type B aircraft. Substitution into Eq. (12-15)
yields
1
1
3600 + (1 − 1)(60) = 114 s
E(∆ Tij ) ≥ 0 . 6( 50) + 0 . 4( 40) +
+
120 90
509
510
Special Topics in Airpor t Planning and Design
Therefore, to release a departure between a pair of arrivals in an error-free
context there must be a gap between successive arrivals of 114 s. In a position
error context, the error term must be computed and added to this value. For a
probability of violation of 10 percent the value of qv is found to be 1.28. The error
in the gap between arrivals is found to be σgqv = 30(1.28) = 38 s. Therefore, in a
position error context there must be a gap between arrivals of 114 + 38 = 152 s to
release a departure between every pair of arrivals.
If the actual interarrival time matrix in Example Problem 12-4 is examined,
it can be seen that a departure can be released only when an arrival of a type A
aircraft is followed by an arrival of a type B aircraft since this is the only case
where the required interarrival time of 152 s is attained. This occurs 25 percent
of the time. Therefore, the capacity of the runway to service mixed operations
in a position error context is
Cm =
3600
[1 . 0 + 1(0 . 25)] = 30 operations per hour
155
A comprehensive example problem using the analytical equations developed
for determining the hourly capacity of a runway is presented to summarize this
section.
Example Problem 12-6 A runway is to service arrivals and departures. The
common approach path is 6 mi long for all aircraft. During a particular interval
of time the runway is serving three types of aircraft with the mix and operating
characteristics shown in Table 12-2. The air traffic separation rules in effect are
given in Table 12-3.
Assume that the standard deviation of the position of airborne aircraft and
the error in the gaps between arrivals are known to be 20 s and that the minimum
separation rules may be violated 10 percent of the time.
First let us find the capacity of the runway system to service arrivals only.
The error-free interarrival time equations are given in Eqs. (12-7) and (12-8).
Using these error-free interarrival time equations the interarrival matrix can be
computed. For example, for a leading B followed by a trailing A, we have
∆TBA =
3(3600)
= 80 s
135
and for a leading A followed by a trailing B, we have
∆TAB =
1
5(3600)
1
3600 = 170 s
+ 6
−
135
110 135
Aircraft
Type
Approach
Speed (mph)
Runway
Occupancy
Time, s
Arrival
Departure
A
135
50
20
15
B
110
40
45
55
C
90
30
35
30
TABLE 12-2
Mix, %
Aircraft Mix and Operating Characteristics for Example
Problem 12-6
Airport Airside Capacity and Delay
Operational Sequence
Air Traffic Separation Rules
Arrival–departure
Clear runway
Departure–arrival
2 mi
Departure–departure
Seconds
Trail
Arrival–arrival
Lead
A
B
C
A
B
C
⎡ 90
⎢ 90
⎢
⎣120
90
90
90
60⎤
60⎥
⎥
60
0⎦
Miles
Trail
Lead
A
B
C
A
B
C
⎡4
⎢5
⎢
⎣6
3
4
4
3⎤
3⎥
⎥
3⎦
TABLE 12-3 Air Traffic Separation Rules for Example Problem 12-6
Continuing these computations for all combinations of leading and trailing aircraft and computing the arrival mix probabilities results in the matrices below.
[ Mij ] :
Leading
Trailing
A ⎡107
⎢
B ⎢170
⎢
C ⎣240
80
131
175
5
[Pij ] :
80⎤
⎥
98 ⎥
⎥
120⎦
Leading
Trailing
A ⎡0 . 04
⎢
B ⎢0 . 09
⎢
C ⎣0 . 07
0 . 09
0 . 20
0 . 16
0 . 07⎤
⎥
0 . 16⎥
⎥
0 . 12⎦
The interarrival buffer time which must be added to the error-free case when
position error is present is given by Eqs. (12-11) and (12-12).
If the probability of violation is 10 percent, then qv = 1.28. Using Eqs. (12-11)
and (12-12) to solve for the buffer, we have for a leading aircraft B and a trailing
aircraft A
bBA = 20(1.28) = 26 s
and for a leading aircraft A followed by a trailing aircraft B
bAB = 20(1 . 28) − 5 ( 1 110 −
1
) 3600 = −5 s
135
But the minimum value of the buffer is always 0.
511
512
Special Topics in Airpor t Planning and Design
Continuing this for all combinations of leading and trailing aircraft gives the
buffer and interarrival time matrices:
[Bij ] :
Leading
Trailing
A
A ⎡26
⎢
B ⎢ 0
⎢
C ⎣ 0
[ Mij + Bij ] :
B
C
26
26⎤
⎥
26⎥
⎥
26⎦
26
0
Leading
Trailing
A
A ⎡133
⎢
70
B ⎢17
⎢
C ⎣240
B
106
157
175
C
106⎤
⎥
124⎥
⎥
146⎦
The expected value of the interarrival time becomes from Eq. (12-10)
E(ΔTij) = 0.04(133) + 0.09(106) + . . . + 0.12(146) = 151 s
The arrival capacity is then from Eq. (12-6)
Ca =
3600
= 24 operations per hour
151
Next let us find capacity of the runway system to service departures only.
The expected value of the departure time is computed from Eq. (12-14) using
the departure-departure time matrix given and the departure mix probability
matrix below. This matrix is based on actual departure-departure times and
always considers error.
[ pij ] :
Leading
A
Trailing
A ⎡0 . 0225
⎢
B ⎢0 . 0825
⎢
C ⎣0 . 0450
B
0 . 0825
0 . 3025
0 . 1650
C
0 . 04500⎤
⎥
0 . 1650⎥
⎥
0 . 0900⎦
The expected value of the departure time is then
E(td) = 0.0225(90) + 0.0825(90) + . . . + 0.0900(60) = 77 s
The departure capacity of the runway is given by Eq. (12-13)
Cd =
3600
= 47 operations per hour
77
Next let us find the probability of releasing a departure after each arrival and
the capacity of the runway system to service mixed operations in the case where
arrivals are given priority over departures.
Airport Airside Capacity and Delay
To release nd departures the required interarrival time is given by Eq. (12-15)
with a buffer term added. Solving for each term in this equation, we have
E(Ri) = 0.20(50) + 0.45(40) + 0.35(30) = 38 s
⎛δ ⎞ ⎡
⎛ 2 ⎞
⎛ 2 ⎞⎤
⎛ 2 ⎞
E ⎜ d ⎟ = ⎢0 . 20 ⎜
⎟⎠ + 0 . 45 ⎜⎝ 110⎟⎠ + 0 . 35 ⎜⎝ 90⎟⎠ ⎥ 3600 = 68 s
135
V
⎝
⎥⎦
⎢
j
⎝ ⎠ ⎣
E(td) = 77 s
E(Bij) = 26(0.68) + 0(0.32) = 18 s
and therefore
E(ΔTij) ≥ 38 + 68 + 18 + 77 (nd − 1)
E(∆Tij) ≥ 124 + 77 (nd − 1)
For one departure we then have a required interarrival time of 124 s, for two
successive departures we have a required interarrival time of 201 s, and for three
successive departures we have a required interarrival time of 278 s.
Therefore, anytime the interarrival time is greater than or equal to 124 and less
than 201 s, one departure may be released between a pair of arrivals. Anytime
the interarrival time is greater than or equal to 201 and less than 278 s, two
departures may be released between a pair of arrivals. Anytime the interarrival
time is greater than or equal to 278 s, three or more departures may be released
between a pair of arrivals.
Examination of the interarrival time matrix, gives the probability of releasing departures between arrivals. Therefore, for one departure the probability is
61 percent, for two successive departures the probability is 7 percent, and we
cannot release more than two successive departures between a pair of arrivals
while maintaining minimum interarrival separations.
The mixed operation hourly capacity is then from Eq. (12-16)
Cm =
3600
[1 + 0 . 61(1) + 0 . 07(2)] = 42 operations
151
Now let us find required interarrival time if at least one departure is to be
released after each arrival and the resulting capacity of the runway system to
service mixed operations under this condition. For this to occur, all values of the
interarrival matrix must be at least 124 s. Therefore, all values of the interarrival
time less than 124 s must be increased to 124 s to release at least one departure
between every pair of arrivals. Therefore, the new required interarrival time
matrix becomes
[Tij ] :
Leading
A
Trailing
A 133
B 170
C 2 40
B
C
124
124
124
146
157
175
which results in
E(∆Tij) = 154 sand the hourly capacity for mixed operations becomes
Cm =
3600
[1 + 0 . 93(1) + 0 . 07(2)] = 48 operations
154
513
514
Special Topics in Airpor t Planning and Design
Therefore, by increasing the interarrival separations anytime that a type A
aircraft follows a type B or type C aircraft, or anytime type B aircraft follows a
type C aircraft, the runway capacity can be increased from 42 to 48 operations per
hour. Small increases in capacity can result in significant decreases in delay.
Application of Techniques for Ultimate
Hourly Capacity
The hourly capacity of the runway system is defined as the maximum
number of aircraft operations that can take place on the runway system
in an hour. The maximum number of aircraft operations depends on a
number of conditions including, but not limited to, the following:
1. The ceiling and visibility conditions
2. The physical configuration of the runway system
3. The air traffic control system separation rules
4. The runway-use strategy
5. The mix of aircraft using the runway system
6. The ratio of arrivals to departures
7. The number of touch and go operations by general aviation
aircraft
8. The number and location of exits from the runway system
It is important to point out that the definition of hourly capacity
of runways in this section differs from that which is delay related,
since the definition of capacity herein contains no assumptions
regarding acceptable levels of delay.
The determination of runway system hourly capacity is normally
made through the use of computer programs developed for that purpose [16, 17, 20, 28, 29]. These programs are capable of accommodating virtually any runway-use configuration at an airport and allow
for the variation in all the parameters which might affect runway
capacity. Based upon the use of these programs and constraining
many of the variables to conform to present operating scenarios, an
airport capacity handbook has been developed which will allow for
the computation of realistic estimates of runway capacity [4, 26]. The
material which follows is based upon the FAA’s Advisory Circular on
estimating airport capacity and delay (AC 150/5360-5) and its
included techniques for determining runway hourly capacity [4, 26]
Parameters Required for Runway Capacity
As noted above, to determine the hourly capacity of the runway system
it is necessary to ascertain the parameters which will affect capacity.
Due to the fact that aircraft separation rules differ in VMC and IMC
weather, it is first necessary to determine the ceiling and visibility
conditions, or more appropriately, the separation rules applicable to
Airport Airside Capacity and Delay
flying conditions when ceiling at the airport is at least 1000 ft and visibility is at least 3 mi. This condition results in VFR flying rules for
arriving and departing aircraft. If either or both of these criteria are
not met, then IFR flying rules are in effect. Of course, all airports have
a period of time when conditions are such that IFR rules apply. Therefore, the hourly capacity of runways is normally specified for each of
these conditions.
The physical runway surfaces at an airport can be used in several
ways. For example, two parallel runways can be used with arrivals
on one runway and departures on the other runway at some point in
time. They could also be used with arrivals and departures on one
surface and arrivals only on the other surface. These runway-use configurations are called the runway use strategies which are dependent
on weather conditions, aircraft types, and the spacing between runways. It is necessary to specify the runway use strategies and the percentage of time each strategy is used.
It is also necessary to specify the types of aircraft which can use a
given runway as quite often shorter runways are constructed for use
by general aviation aircraft only. The aircraft which can use a runway
are defined in terms of a mix index. This index is simply an indication
of the level of operations on the runway by large and heavy aircraft.
The mix index is given by Eq. (12-17).
MI = C + 3D
(12-17)
where MI = mix index
C = percentage of aircraft weighing more than 12,500 lb but
less than 300,000 lb on the runway
D = percentage of aircraft with maximum gross weight of
300,000 lb or greater in the mix of aircraft using the
runway
The percentage of arrival operations which occur on the runway
is also necessary. This is because the spacing rules for arrivals and
departures differ. There are three types of operations which can
occur, namely, arrivals, departures, and touch-and-go operations. A
touch-and-go operation is most commonly used by general aviation
pilots practicing approaches, landings, and takeoffs. These operations are seldom conducted in poor weather. For the purpose of
determining capacity, the parameter called percent arrivals is used
to define the proportion of each type of operation which occurs on
the runway. In VFR conditions it is also necessary to find the percentage of touch-and-go operations. At times small general aviation
airports may have touch-and-go operations which can approach
30 percent of all operations.
The location of runway exits for arriving aircraft must also be
known since this affects runway occupancy time. Depending upon
the nature of the aircraft using a runway exits should be located at
positions which will allow minimum runway occupancy times. If this
515
516
Special Topics in Airpor t Planning and Design
is not the case, the capacity will be reduced because of excessive runway occupancy times.
As a result of extensive research conducted to determine the
capacity of runway systems, the FAA has published a series of charts
to determine runway capacity [4, 26]. These charts are used to determine the runway capacity through Eq. (12-18).
C = CbET
(12-18)
where C = hourly capacity of the runway-use configuration in operations per hour
Cb = ideal or base capacity of the runway-use configuration
E = exit adjustment factor for the number and location of runway exits
T = touch-and-go adjustment factor
The use of this equation and the charts are illustrated by Example
Problem 12-7.
Example Problem 12-7 It is required to find the VFR and IFR hourly capacity of
the runway system shown in Fig. 12-12. The runway-use strategy is as shown.
In VFR weather, the traffic consists of 3 single-engine, 20 light twin-engine,
25 large transport-type, and 2 wide-bodied aircraft. Arrivals constitute 40 percent
of the operations and there are approximately three touch–and-go operations.
r
Te
l
na
mi
0
1,000 2,000 3,000 4,000 ft
FIGURE 12-12 Runway layout for Example Problem 12-7.
Airport Airside Capacity and Delay
VFR Mix
IFR Mix
Aircraft
Class
No.
Single-engine
A
13
26.0
Twin-engine
B
10
Transports
C
25
Wide-bodied
D
Total
%
No.
%
2
5.9
20.0
5
14.7
50.0
25
73.5
2
4.0
2
5.9
50
100.0
34
100.0
TABLE 12-4 Tabulation of Aircraft Mix Index for Example Problem 12-7
In IFR, the small aircraft population count drops to two single-engine and five
light twin-engine aircraft. The arrival rate increases to 50 percent and there are
no touch-and-go operations.
The capacity of intersecting runways is a function of the location of the intersection from both the arrival and departure threshold. The closer that the intersection is to these thresholds, the greater the capacity. The aircraft are grouped
into various classes in VFR and IFR conditions in Table 12-4. The charts used
for this configuration in VFR and IFR are taken from references [4, 26] and are
given in Figs. 12-13 and 12-14.
From the this tabular data, the mix index can be found for VFR from
Eq. (12-17) as
MI = C + 3D = 50.0 + 3(4.0) = 62.0
and for IFR
MI = C + 3D = 73.5 + 3(5.9) = 91.2
Using the VFR mix index of 62.0 and the percent arrivals (PA) equal to
40, the base capacity Cb is found from the left side of Fig. 12-13 as about
95 operations per hour. This base value is then adjusted for touch-and-go
operations and the location of exits using the right side of this figure. From
the given data, the percentage of touch-and-go operations in VFR is equal to
6 percent. Therefore, the touch-and-go adjustment factor T is equal to 1.03. For
the mix index of 62.0, only those exits located between 3500 and 6500 ft from
the arrival threshold can be counted. There are two such exits, one at 4500 ft
and the other at 6000 ft. Therefore, the table then gives an exit factor E of 0.97
for 40 percent arrivals.
Therefore, the hourly capacity of the runway system in VFR is from
Eq. (12-18)
C = 95(1.03)(0.97) = 95 operations per hour
The IFR capacity is determined similarly from Fig. 12-14. This will yield,
for an IFR mix index of 91.2 and a percent arrivals (PA) of 50 percent, the base
capacity, touch-and-go factor, and exit factor as
C = 58(1.00)(0.97) = 56 operations per hour
517
518
TOUCH & GO FACTOR T
HOURLY CAPACITY BASE C*
HOURLY CAPACITY BASE (C*) (OPERATIONS PER HOUR)
120
110
PERCENT
ARRIVALS
100
Percent
Touch & Go
0
1 to 10
11 to 20
21 to 30
31 to 40
41 to 50
Mix Index–
Percent (C+3D)
0 to 180
0 to 70
0 to 70
0 to 40
0 to 10
0 to 10
TOUCH & GO FACTOR T
1.00
1.03
1.06
1.13
1.26
1.33
40
90
C* × T × E = Hourly Capacity
50
80
EXIT FACTOR E
70
60
60
50
To determine Exit Factor E:
1. Determine exit range for appropriate mix index from table below
2. For arrival runways, determine the average number of exits (N) which
are: (a) within appropriate exit range, and (b) separated by at least 750 feet
3. If N is 4 or more, Exit Factor = 1.00
4. If N is less than 4, determine Exit Factor from table below for appropriate
mix index and percent arrivals
40
30
20
0
20
40 60 80 100 120 140 160 180
MIX INDEX–PERCENT (C+3D)
Mix Index–
Percent (C+3D)
Exit Range
(Feet from
threshold)
0 to 20
21 to 50
51 to 80
81 to 120
121 to 180
2000 to 4000
3000 to 5500
3500 to 6500
5000 to 7000
5500 to 7500
FIGURE 12-13 Hourly capacity in VFR for runway operations in Example Problem 12-7.
40% Arrivals
N=0 N=1N=2
or 3
0.86 0.88 0.94
0.84 0.91 0.98
0.81 0.91 0.97
0.83 0.90 0.95
0.93 0.99 1.00
EXIT FACTOR E
50% Arrivals
N=0 N=1N=2
or 3
0.80 0.85 0.93
0.71 0.85 0.92
0.76 0.85 0.91
0.80 0.86 0.92
0.84 0.94 0.98
60% Arrivals
N=0 N=1N=2
or 3
0.71 0.83 0.93
0.71 0.85 0.92
0.75 0.84 0.91
0.80 0.87 0.92
0.85 0.94 0.98
TOUCH & GO FACTOR T
HOURLY CAPACITY BASE C*
HOURLY CAPACITY BASE (C*) (OPERATIONS PER HOUR)
100
T = 1.00
90
PERCENT
ARRIVALS
80
40
70
C* × T × E = Hourly Capacity
60
50
50
60
EXIT FACTOR E
To determine Exit Factor E:
1. Determine exit range for appropriate mix index from table below
2. For arrival runways, determine the average number of exits (N) which
are: (a) within appropriate exit range, and (b) separated by at least 750 feet
3. If N is 4 or more, Exit Factor = 1.00
4. If N is less than 4, determine Exit Factor from table below for appropriate
mix index and percent arrivals
40
30
20
10
0
0
519
FIGURE 12-14
20
40 60 80 100 120 140 160 180
MIX INDEX–PERCENT (C+3D)
Mix Index–
Percent (C+3D)
Exit Range
(Feet from
threshold)
0 to 20
21 to 50
51 to 80
81 to 120
121 to 180
2000 to 4000
3000 to 5500
3500 to 6500
5000 to 7000
5500 to 7500
Hourly capacity in IFR for runway operations in Example Problem 12-7.
40% Arrivals
N=0 N=1N=2
or 3
0.98 1.00 1.00
0.92 0.99 1.00
0.91 0.98 1.00
0.94 0.98 1.00
0.95 1.00 1.00
EXIT FACTOR E
50% Arrivals
N=0 N=1N=2
or 3
0.99 1.00 1.00
0.91 0.99 1.00
0.90 0.97 1.00
0.91 0.97 1.00
0.92 0.99 1.00
60% Arrivals
N=0 N=1N=2
or 3
0.98 1.00 1.00
0.92 1.00 1.00
0.92 0.99 1.00
0.91 0.97 1.00
0.91 0.99 1.00
520
Special Topics in Airpor t Planning and Design
Computation of Delay on Runway Systems
Delay to aircraft is defined as the difference between the actual time
it takes an aircraft to maneuver on the runway and the time it would
take the aircraft to maneuver without interference from other aircraft.
The runway is defined as the entire runway system including approach
and departure airspace [26]. To compute runway system delay, it is
necessary to analyze each runway-use configuration for the demand
placed upon it. To compute annual runway delay, it is necessary to
determine the percentage of time each runway-use configuration is
used throughout the year. Normally this will require knowledge of the
following factors:
1. The hourly capacity of the runway-use strategy in VFR and IFR
2. The pattern of hourly, daily, and monthly aircraft demand
during the design year
3. The peaking of demand during the design hour
4. The frequency of occurrence of runway strategies, ceiling,
and visibility conditions
The techniques are outlined in detail in references [4, 26] but it is
sufficient to note that the computation of annual delay is a very
tedious and time-consuming process, and now is generally performed
on computers [17, 28, 29]. The elements of the process are shown in
Example Problem 12-8, which uses charts from the FAA Airport
Capacity and Delay Advisory Circular AC 150/5360-5.
Example Problem 12-8 The hourly delay to aircraft operating on the runway
system in Example Problem 12-7 is to be found for both VFR and IFR conditions.
It is known that the peak 15-min demand in the peak hour is 20 operations in
VFR and 10 operations in IFR.
The hourly capacity of the runway system was found earlier and yielded
95 operations per hour in VFR and 56 operations per hour in IFR. The hourly
demand was 50 operations per hour in VFR and 34 operations per hour in
IFR. Therefore, the ratio of hourly demand to hourly capacity is computed
as for VFR
D 50
=
= 0 . 53
C 95
and for IFR
D 34
=
= 0 . 61
C 56
Figure 12-15, which is taken from references for this runway-use strategy
[4, 26], the FAA Airport Capacity Advisory Circular, gives the variation of the
arrival delay index (ADI) and the departure delay index (DDI) for VFR and IFR
conditions for this runway use for 50 percent arrivals.
Airport Airside Capacity and Delay
ARRIVAL DELAY INDEX
40% ARRIVALS
D/C RATIO
1.2
1.0 OR LESS
0.8
0.6
0.4
FOR D/C RATIO OF 1.4
OR MORE
ADI = 1.0
0.2
0 20 40 60 80 100 120140160180
1.0
50% ARRIVALS
ARRIVAL DELAY INDEX (ADI)
1.0
ARRIVAL DELAY INDEX (ADI)
ARRIVAL DELAY INDEX (ADI)
VFR Conditions
0.8
0.6
0.4
FOR D/C RATIO OF 0 TO 1.5
ADI = 1.0
0.2
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
60% ARRIVALS
1.0
0.8
0.6
0.4
FOR D/C RATIO OF 0 TO 1.5
ADI = 1.0
0.2
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
MIX INDEX–PERCENT (C+3D)
D/C RATIO
0.8
0.6
0.4 OR LESS
0.8
0.6
0.4
FOR D/C RATIO OF 1.0
OR MORE
DDI = 1.0
0.2
0 20 40 60 80 100 120140160180
1.0
DEPARTURE DELAY INDEX (DDI)
1.0
DEPARTURE DELAY INDEX (DDI)
DEPARTURE DELAY INDEX (DDI)
DEPARTURE DELAY INDEX
40% ARRIVALS
50% ARRIVALS
D/C RATIO
1.0 OR MORE
0.8
0.8
0.6
0.6
0.4 OR LESS
0.4
0.2
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
60% ARRIVALS
1.0
D/C RATIO
1.0 OR MORE
0.8
0.6
0.4 OR LESS
0.8
0.6
0.4
0.2
MIX INDEX–PERCENT (C+3D)
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
ARRIVAL DELAY INDEX = 1.00
IFR Conditions
0.8
0.6
D/C RATIO
0 TO 1.5
0.4
0.2
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
1.0
50% ARRIVALS
0.8
0.6
D/C RATIO
0 TO 1.5
0.4
0.2
0 20 40 60 80 100 120140160180
DEPARTURE DELAY INDEX (DDI)
1.0
DEPARTURE DELAY INDEX (DDI)
DEPARTURE DELAY INDEX (DDI)
DEPARTURE DELAY INDEX
40% ARRIVALS
60% ARRIVALS
1.0
0.8
0.6
0.4
D/C RATIO
0 TO 1.5
0.2
MIX INDEX–PERCENT (C+3D)
0 20 40 60 80 100 120140160180
MIX INDEX–PERCENT (C+3D)
Arrival and departure delay indices for Example Problem 12-8.
FIGURE 12-15
Based upon the respective mix indices for VFR and IFR conditions, this chart
gives for VFR
ADI = 1.00
and
DDI = 0.65
ADI = 1.00
and
DDI = 0.57
and for IFR
These indices are combined with the respective ratios of demand to capacity
to arrive at the arrival delay factor (ADF) and the departure delay factor (DDF) as
follows:
ADF = (ADI)
D
C
DDF = (DDI)
D
C
and
Therefore, for arrivals we have in VFR
ADF = (1.00)(0.53) = 0.53
DDF = (0.65)(0.53) = 0.34
521
Special Topics in Airpor t Planning and Design
and in IFR we have
ADF = (1.00)(0.61) = 0.61
DDF = (0.57)(0.61) = 0.35
The average delay for each aircraft is then found from Fig. 12-16 by using the
above delay factors and the demand profile factor.
The demand profile factor is simply a measure of the peaking of demand
in the hour and is defined as the peak 15-min demand divided by the hourly
demand. Therefore, the demand profile factors (DPF) are in VFR
DPF =
20
(100) = 40
50
DPF =
10
(100) = 34
34
and in IFR
From Fig. 12-16, the average delays are found in VFR as
Arrival delay = 1.4 min per aircraft
Departure delay = 0.7 min per aircraft
and in IFR
Arrival delay = 1.0 min per aircraft
Departure delay = 0.3 min per aircraft
12
10
Average delay per aircraft, min
522
8
6
4
Demand profile factor 50
45
40
35
30
2
25
0
0
0.2
0.4
0.6
Delay factor
0.8
1.0
FIGURE 12-16 Variation of average aircraft delay with delay factor (Federal
Aviation Administration).
Airport Airside Capacity and Delay
Since, there are equal arrivals and departures, the total delay to all aircraft in
this hour in both VFR and IFR can be found.
Total delay VFR = 50[1.4(0.5) + 0.7(0.5)] = 52.5 min
Total delay IFR = 34[1.0(0.5) + 0.3(0.5)] = 22.1 min
The computation of delay at an airport over various periods of
time requires that this procedure be repeated for each hour, day,
and month for each runway-use strategy and weather condition
and summed over the period of interest. The process is shown in
Example Problem 12-9 for the computation of delay on a daily
basis.
Example Problem 12-9 To illustrate the airport capacity handbook method [4, 26]
of computing the delay throughout a typical day, let us determine the daily delay
to aircraft if the runway-use strategy shown in Fig. 12-12 is used throughout the
day. The hourly capacity of the runway-use strategy is 80 operations per hour
and the number of arrivals equals the number of departures in each hour. The
hourly demand throughout the day is given in Table 12-5.
Let us assume that the mix index is equal to 70 and demand profile factor is
equal to 25. Both the mix index and the demand profile factor are the same in
each hour. Let us also assume that VFR conditions exist throughout the day.
To solve this problem, it is necessary to compute the arrival delay index, the
departure delay index, the arrival delay factor, and the departure delay factor for
each hour during the day. The computational procedure differs depending upon
whether when the hourly demand is less than or equal to the hourly capacity or
the hourly demand is greater than the hourly capacity.
For the condition when hourly demand is less than or equal to the hourly
capacity the procedure is the same as that shown in Example Problem 12-8.
For example, in hour 1000 the aircraft demand is 60 operations per hour and
the runway capacity is 80 operations per hour. Therefore, the ratio of hourly
demand to hourly capacity is 60 ÷ 80 = 0.75.
From Fig. 12-15, the arrival delay index (ADI) is 1.0 and the departure delay
index (DDI) is 0.70. The arrival delay factor is then
ADF = ADI
D
= 1 . 0(0 . 75) = 0 . 75
C
Hour
Demand
Hour
Demand
Hour
Hour
Demand
0000
10
0600
20
1200
Demand
50
1800
100
0100
10
0700
40
1300
50
1900
70
0200
10
0800
60
1400
40
2000
40
0300
10
0900
50
1500
70
2100
30
0400
10
1000
60
1600
110
2200
20
0500
10
1100
50
1700
120
2300
10
TABLE 12-5 Hourly Aircraft Runway Demand on Typical Day for Example
Problem 12-9
523
524
Special Topics in Airpor t Planning and Design
and the departure delay factor is
DDF = DDI
D
= 0 . 70(0 . 75) = 0 . 53
C
From Fig. 12-16, using these delay factors and a demand profile factor of 25,
an average arrival delay of 1.2 min and an average departure delay of 0.2 min
are found.
Since the number of arrivals is equal to the number of departures the total
delay in hour 1000 is then equal to
Delay = 1.2(0.5)(60) + 0.2(0.5)(60) = 42 aircraft-minutes
The procedure is the same for hours 0000 through hour 1500.
However, beginning at hour 1600 the hourly demand exceeds the hourly
capacity for 3 h. These are called overloaded hours. The cumulative demand for
these 3 h, 330 operations, exceeds the cumulative capacity available for these
3 h, 240 operations. Therefore, some of these aircraft are not serviced in these
3 h and spill over into later hours. The later hours serve this backlog of demand
until the backlog is cleared up. This is shown in Table 12-6. The time from hour
1600 to hour 2000 is called the saturated period.
For the overloaded period, hours 1600 through 1800, the total demand is
divided by the total capacity to arrive at the average demand to capacity ratio
during the overloaded hours. Therefore,
D 110 + 120 + 100
=
= 1 . 38
C
80 + 80 + 80
From Fig. 12-15, the arrival delay index is 1.00 and the departure delay
index is 0.75 during the overloaded hours. This results in an arrival delay factor
of 1.00 × 1.38 = 1.38 and a departure delay factor of 0.75 × 1.38 = 1.04.
Figure 12-17, which is taken from the FAA airport capacity advisory circular,
gives the aircraft delay in the saturated period when the period of overload
is 3 h. From this figure, using a demand profile factor of 25, an average arrival
delay over this period is found to be 35 min per arrival and an average departure
delay over this period is found to be 4 min per departure.
The delay in the saturated period is found by adding the total demand in the
saturated period and multiplying by the average delay per operation. The total
demand is then the demand from hours 1600 through 2000, or 440 operations.
Hour
Demand
Capacity
Overload
Cumulative
Overload
1500
70
80
0
0
1600
110
80
+30
+30
1700
120
80
+40
+70
1800
100
80
+20
+90
1900
70
80
–10
+80
2000
40
80
–40
+40
2100
30
80
–50
0
TABLE 12-6
Overloaded and Saturated Hours Example Problem 12-9
Airport Airside Capacity and Delay
DURATION OF OVERLOAD PHASE
THREE HOURS
35
30
25
20
10
5
5 50
15
25 3
0 35
40
4
AVERAGE DELAY PER AIRCRAFT
DURING SATURATED CONDITIONS (MINUTES)
40
DEMAND PROFILE FACTOR
0
1.0
1.4
1.5
1.1
1.2
1.3
DELAY FACTOR DURING OVERLOAD PHASE
FIGURE 12-17 Average aircraft delay during saturated conditions for an
overload period of 3 h (Federal Aviation Administration).
Since the number of arrivals is equal to the number of departures in each
hour, this yields a total delay in the saturated period of
Delay = 440(0.5)(35) + 440(0.5)(4) = 8580 aircraft-minutes
In the hours 2100 through 2300 the demand is once again less than the capacity, and the backlog has been cleared up. Therefore, the procedure is the same as
used for hours 0000 through 1500.
The results are displayed in tabular format in Table 12-7. The result is that
the total delay on this day is equal to 8799 aircraft-hours. The average delay to
aircraft on this day is 8799/1050 = 8.4 min.
Graphical Methods for Approximating Delay
A relatively simple technique for estimating delays when demand
exceeds capacity has been used in aviation studies [19]. This method is
called a deterministic queuing model. In this method, a time scale is
established on the X axis to represent the time period being analyzed. On
the Y axis, a scale is established for the cumulative number of aircraft
which have arrived by some point in time. Therefore, a point on the plot
represents the total number of aircraft which have arrived at that point
525
526
Arrivals
Departures per
Minutes of Delay Hourly
Hour
Demand
Ratio
D/C
0000
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0100
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0200
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0300
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0400
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0500
10
0.13
1.0
0.13
0.65
0.08
0
0
0
0600
20
0.25
1.0
0.25
0.65
0.16
0
0
0
0700
40
0.50
1.0
0.25
0.67
0.34
0
0
0
0800
60
0.75
1.0
0.75
0.70
0.53
1.2
0.2
42
0900
50
0.63
1.0
0.63
0.68
0.43
0.4
0.1
13
1000
60
0.75
1.0
0.75
0.70
0.53
1.2
0.2
42
1100
50
0.63
1.0
0.63
0.68
0.43
0.4
0.1
13
1200
50
0.63
1.0
0.63
0.68
0.43
0.4
0.1
13
1300
50
0.63
1.0
0.63
0.68
0.43
0.4
0.1
13
ADI
ADF
DDI
DDF
Arrival
Departures
Total
1400
40
0.50
1.0
0.50
0.67
0.34
0.2
0
1500
70
0.88
1.0
0.88
0.73
0.64
1.8
0.4
1600
110
1700
120
1800
100
1.38
1.0
1.38
0.75
1.04
1900
70
2000
40
2100
30
0.38
1.0
0.38
0.65
0.25
2200
20
0.25
1.0
0.25
0.65
2300
10
0.13
1.0
0.13
0.65
Daily
1050
TABLE 12-7
Tabulation of Hourly Delay for Example Problem 12-9
35
4
77
4
8580
0.1
0
2
0.16
0
0
0
0.08
0
0
0
8799
527
Special Topics in Airpor t Planning and Design
in time. The curve which results from plotting the succession of points is
actually a representation of the demand D(t). A line of constant, or for
that matter variable slope, can be drawn on the same graph to show the
service capabilities, or capacity, of a facility. This is the service function
S(t). An illustration of such a graph is given in Fig. 12-18.
In this figure, point A represents the time when the demand rate
begins to exceed the service rate or capacity. Therefore, delays and
queues begin to develop. At point B, the delays and queues which
have built since time t1 will have dissipated, and the demand rate is
now less than the service rate. A review of the results displayed on
this figure shows that
1. Delays occur from time t1 to time t4.
2. The total number of aircraft delayed is the difference between
P4 and P1.
3. From time t1 to time t3 the demand rate exceeds the service
rate, and delays and queues increase during this time period.
4. The maximum delay and maximum queue length occur at
time t3 since the demand rate becomes less than the service
rate at this time.
5. The delay to any aircraft is given by the magnitude of a horizontal line drawn between the two curves.
P4
Cumulative aircraft arrivals since t0
528
B
P3
Queue
length
P2
Service
rate
Delay
time
A
P1
t0
t1
t2
FIGURE 12-18 Deterministic queuing diagram.
t3
t4 Time
Airport Airside Capacity and Delay
6. The length of a queue at any point in time is given by the
magnitude of a vertical line drawn between the two curves at
that point in time.
7. The area between the two curves represents the total delay to
all aircraft which are delayed from time t1 to time t4.
This type of analysis is useful in airport planning to estimate the
magnitude of delays, number of aircraft delayed, and the cost of
delay under assumed operating conditions. It does not, however,
give an indication of the delays which occur when average demand
is less than the capacity. These are normally calculated by the equations or methods discussed earlier.
Example Problem 12-10 illustrates the application of this technique to a runway system.
Example Problem 12-10 The hourly aircraft demand during a typical day at an
airport is given in Table 12-5. The runway system has a capacity to service
80 aircraft per hour without delay.
An analysis of the delay when demand exceeds capacity is to be conducted.
For discussion purposes the hourly pattern of demand and the capacity are
plotted in Fig. 12-19. The deterministic model makes the assumption that delay
occurs only when demand exceeds capacity. This figure shows that up until hour
1600 the aircraft demand in any hour is less than the runway capacity and therefore delays do not occur. However, beginning at hour 1600 the aircraft demand
begins to exceed the runway capacity and therefore delays begin to accrue from
this point in time.
160
Delay Begins
140
Aircraft Demand
120
100
Runway Capacity
80
60
40
20
0
FIGURE 12-19
200
400
600
800 1000 1200 1400 1600 1800 2000 2200 2400
Time
Pattern of hourly aircraft demand for Example Problem 12-10.
529
Special Topics in Airpor t Planning and Design
1200
Delay Period
1600 to 2148h
1100
S(t)
D(t)
1000
900
Total
Delayed
Aircraft
= 464
800
Cumulative Aircraft
530
700
Greatest Delay
= 67.5 minutes
Greatest Queue
= 90 aircraft
600
500
400
Runway
Capacity
300
80
200
1
100
0
400
800
1200
Time
1600
2000
2400
FIGURE 12-20 Plot of cumulative aircraft arrivals versus time for Example
Problem 12-10.
The data in Table 12-5 are plotted in Fig. 12-20, where the cumulative hourly
demand D(t) and cumulative service rate S(t) are plotted versus time. This figure
again shows that at hour 1600 the demand rate begins to exceed the capacity and
therefore delay will begin in hour 1600.
The shaded area between the curves represents the period when aircraft
delays occur. However, due to the scale on this figure, it is difficult to determine
the values of the greatest delay to any aircraft, the greatest X value within
the shaded area, the greatest number (queue) of aircraft delayed, the largest
Y value within the shaded area, or the total aircraft-hours of delay, the shaded
area. Since only the period after hour 1600 contains delay and the Y value
within the shaded area represents the difference between demand and capacity, a plot of the cumulative difference between demand and capacity versus
time from hour 1600, tabulated in Table 12-8, is shown in Fig. 12-21. This
figure effectively expands the scale of the shaded area in Fig. 12-20 and is
much easier to use to determine the values of the above delay and queue
length parameters.
The greatest Y value on Fig. 12-21 represents the greatest number of aircraft
delayed at any point in time, the time period when the curve is above the X axis
is the time period during which delay occurs, and the area of the curve above
the X axis is the total aircraft-hours of delay.
Airport Airside Capacity and Delay
End Hour
Demand
Demand-Capacity
Cumulative
Demand-Capacity
1500
0
1600
110
+30
+30
1700
120
+40
+70
1800
100
+20
+90
1900
70
−10
+80
2000
40
−40
+40
2100
30
−50
−10
2200
20
−60
−70
TABLE 12-8 Cumulative Demand Minus Capacity during Delay Period for
Example Problem 12-10
+100
90
+80
80
70
Demand–Capacity
+60
+40
40
30
+20
0.8h
–20
–10
–40
–60
–80
1600
–70
1700
1800
1900
2000
Time
2100
2200
2300
FIGURE 12-21 Plot of demand minus capacity for delay period for Example
Problem 12-10.
The largest number of aircraft delayed at any point in time is found to be 90.
The service time for an aircraft is the reciprocal of the runway capacity, or the
runway will service one aircraft in 0.75 min. The delay time for the aircraft which
is delayed the longest is therefore 90(0.75) = 67.5 min. The total number of aircraft
hours of delay is the area under this curve or 306 aircraft-hours.
All of the aircraft in hours 1600 to 2000 and 80 percent of the aircraft in hour
2100 are delayed. This amounts to 464 aircraft. Therefore, the average delay to
delayed aircraft on this day is 306/464 = 0.66 h = 40 min. The average delay to
all aircraft using the runway on this day is 306/1050 = 0.29 h = 17 min.
531
532
Special Topics in Airpor t Planning and Design
Application of Techniques for Annual Service Volume
Annual service volume is a level of annual aircraft operations that may
be used as a reference in preliminary planning. As annual aircraft
operations approach annual service volume, the average delay to
each aircraft throughout the year may increase rapidly with relatively
small increases in aircraft operations, thereby causing levels of service on the airfield to deteriorate.
When annual aircraft operations on the airfield are equal to
annual service volume, average delay to each aircraft throughout the
year is on the order of 1 to 4 min. A more precise estimate of actual
average delay to aircraft at a particular airport can be obtained using
these procedures if this is required in the planning application.
Simplified estimating procedures are available for airport planning purposes to determine the annual service volume and average
aircraft delay for runway configurations existing at airports. These
procedures should only be used for preliminary estimating purposes.
These procedures allow for approximations of
• The hourly capacity of runways in VFR and IFR conditions
• The annual service volume of runways
• The average annual delay to aircraft on runways
Hourly capacities and annual service volumes for a number of
runway configurations are presented in Table 12-9. An approximate estimate of average aircraft delay per year for any runway
configuration can be obtained from Fig. 12-22. The data shown in
Table 12-9 and Fig. 12-22 are based on a number of assumptions
which include
1. A representative range of mix indices sufficient for estimating
purposes.
2. The hourly capacities are those correspond to the runway utilization which produces the largest capacity consistent with
current air traffic control procedures and practices, and this
configuration is used 80 percent of the time.
3. One-half of the demand for the use of the runways is by arriving aircraft, and thus, the number of arriving and departing
aircraft in a specified period of time is equal.
4. The percentage of touch-and-go operations is a function of
the mix index of the airport.
5. Sufficient taxiways exist to permit the capacity of the runways to be fully realized.
6. The impact on capacity of a taxiway crossing an active runway is assumed to be negligible.
Airport Airside Capacity and Delay
Runway
Configuration
Runway
Configuration
Mix
Mix
Index,
Index,%%
(C
(C ++3D)
3D)
Hourly
Capacity,
Hourly Capacity,
Operations
Operations
perper
Hour
hour
Annual
Annual
Service
service
Volume,
volume,
Operations
operations
year
perper
Year
VFR
VFR
IFR
IFR
A
0–20
21–50
51–80
81–120
121–180
98
74
63
55
51
59
57
56
53
50
230,000
195,000
205,000
210,000
240,000
B
0–20
21–50
51–80
81–120
121–180
197
145
121
105
94
59
57
56
59
60
355,000
275,000
260,000
285,000
340,000
0–20
21–50
51–80
81–120
121–180
197
149
126
111
103
119
114
111
105
99
370,000
320,000
305,000
315,000
370,000
0–20
21–50
51–80
81–120
121–180
295
219
184
161
146
62
63
65
70
75
385,000
310,000
290,000
315,000
385,000
0–20
21–50
51–80
81–120
121–180
394
290
242
210
189
119
114
111
117
120
715,000
550,000
515,000
565,000
675,000
F
0–20
21–50
51–80
81–120
121–180
98
77
77
76
72
59
57
56
59
60
230,000
200,000
215,000
225,000
265,000
G
0–20
21–50
51–80
81–120
121–180
150
108
85
77
73
59
57
56
59
60
270,000
225,000
220,000
225,000
265,000
0–20
21–50
51–80
81–120
121–180
132
99
82
77
73
59
57
56
59
60
260,000
220,000
215,000
225,000
265,000
C
700' to 2,499'
4,300' or more
700' to 2,499'
D
2,500' to 3,499'
700' to 2,499'
E
3,500' or more
700' to 2,499'
H
TABLE 12-9 Preliminary Estimates of Hourly and Annual Ultimate Capacities
533
Hourly
Capacity,
Operations
per Hour
IFR
Annual
Service
Volume,
Operations
per Year
150
108
85
77
73
59
57
56
59
60
270,000
225,000
220,000
225,000
265,000
J
0–20
21–50
51–80
81–120
121–180
132
99
82
77
73
59
57
56
59
60
260,000
220,000
215,000
225,000
265,000
K
700' to 2,499'
0–20
21–50
51–80
81–120
121–180
197
145
121
105
94
59
57
56
59
60
355,000
275,000
260,000
285,000
340,000
4,300' or more
0–20
21–50
51–80
81–120
121–180
197
149
126
111
103
119
114
111
105
99
370,000
320,000
305,000
315,000
370,000
0–20
21–50
51–80
81–120
121–180
295
210
164
146
129
59
57
56
59
60
385,000
305,000
275,000
300,000
355,000
0–20
21–50
51–80
81–120
121–180
295
210
164
146
129
59
57
56
59
60
385,000
305,000
275,000
300,000
355,000
0–20
21–50
51–80
81–120
121–180
197
147
145
138
125
59
57
56
59
60
355,000
275,000
270,000
295,000
350,000
Mix
Index, %
(C + 3D)
VFR
I
0–20
21–50
51–80
81–120
121–180
Runway Configuration
L
700' to 2,499'
M
700' to 2,499'
N
O
Less than 2,500'
Less than 2,500'
TABLE 12-9
(Continued)
534
Preliminary Estimates of Hourly and Annual Ultimate Capacities
Airport Airside Capacity and Delay
7. There is sufficient airspace to accommodate all aircraft wishing to use the runways and aircraft operations are conducted
in a radar environment with at least one runway equipped
with an instrument landing system.
8. IFR conditions occur 10 percent of the time.
9. Representative hourly and daily ratios are a function of the
mix index.
The order-of-magnitude relationship between average annual
delay per aircraft and annual service volume depicted in Fig. 12-22
was derived from historical traffic records and a range of assumptions on likely operating conditions, as itemized above. Typically, the
upper portion of the shaded band on Fig. 12-22 is representative of
airports primarily serving air carrier operations. Airports serving primarily general aviation operations may typically fall anywhere
within the entire shaded band. The dotted curve is the average of the
upper and lower limits of the band indicated. Example Problem 12-11
shows the use of these approximate procedures.
8
7
Average delay per year, min
6
5
4
3
2
1
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Ratio of annual demand to annual service volume
1.1
FIGURE 12-22 Relationship between average aircraft delay and ratio of
annual demand to annual service volume (Federal Aviation Administration).
535
536
Special Topics in Airpor t Planning and Design
Example Problem 12-11 An airport has a single runway available to service arrivals and departures. The projected annual demand in a future year is 220,000
operations. The aircraft mix is estimated to consist of 21 percent small single
engine, 20 percent small multiengine, 55 percent large commercial aircraft, and
4 percent heavy aircraft. Air carrier operations predominate at the airport and
very few touch-and-go operations occur.
It is necessary to determine the annual service volume and average delay
to aircraft for the single runway and for closely spaced parallels which may be
constructed. The mix index at the airport is computed as
MI = 55 + 3(4) = 67
From Table 12-9, the annual service volume for each runway is found from
runway configuration diagrams A and B with the mix index range of 51 to 80
Single-runway ASV = 205,000 operations
Close parallel-runway ASV = 260,000 operations
The ratios of annual demand to annual service volume are then computed
for both situations as for a single runway
Demand 220, 000
=
= 1 . 07
ASV
205, 000
and for close parallel runways
Demand 220, 000
=
= 0 . 84
ASV
260, 000
Using the upper half of the graph in Fig. 12-22, since this is an predominantly
air carrier airport, yields the average annual delay per aircraft. These values are
for a single runway between 4.0 and 6.0 min per operation and for close parallel
runways between 1.2 and 1.7 min per operation.
It is clear that the construction of close parallel runways will represent a
benefit in terms of decreased delays. However, a detailed analysis of this should
be performed prior to making a decision on construction modifications since this
procedure is approximate and based upon the assumptions noted above.
The determination of realistic estimates of aircraft delay is a
tedious and time-consuming process, as was shown in Example Problem 12-9. The Airport Capacity Advisory Circular outlines in detail
the procedures which are required [4, 26]. Basically, to compute aircraft delay it is necessary to have estimates of the hourly demand on
the runway system, the hourly capacity of each runway-use configuration, and the percentage of time each runway-use configuration is
utilized in each weather condition. The process can be performed for
a typical day, for several days, or on a monthly or annual basis.
Fortunately, the FAA has developed a computer program for the
determination of annual delay at an airport [17, 28, 29]. This program
compiles average aircraft delay by runway-use configuration, by weather
condition, on a daily, weekly, monthly, and annual basis and it presents
an annual distribution of the magnitude of delay at the airport.
Airport Airside Capacity and Delay
The annual service volume may be related to specific criteria for
the level of average aircraft delay. To do this, the annual demand on
the airfield is varied over a range of values which represent upper
and lower bounds on the specified average delay criteria. By plotting
the average aircraft delay versus the annual demand a curve is developed showing the variation in average aircraft delay as a function of
annual demand. By finding the annual demand which corresponds
to the delay criteria the annual service volume is defined. It should be
noted that the same process may be used on hourly basis to find the
practical hourly capacity of a runway-use configuration. The computer model cited above is very useful for this purpose.
Simulation Models
While mathematical models form the fundamental basis for estimating capacity and delay of an airport, such models become extremely
complex for most airports. Airports with multiple runways and taxiways, varying use configurations, fleet mixes, and weather conditions
render strict analytical methods extremely difficult if not impossible
to accurately estimate airfield capacity and delay. Fortunately, superior
computing power has become readily available since the late 1990s to
apply computer simulation models to accurately and dynamically
estimate operating capacity and delays for current, as well as proposed
airfield configurations.
The theory and practice of simulation modeling is a highly complex study that exceeds the scope of this text. The Federal Aviation
Administration has a team dedicated to development and application
of a variety of software tools designed to simulate various elements of
the airport and airspace system. These tools simulate and analyze
operations from capacity, delay, as well as operational feasibility perspectives. Specific FAA software models include the FAA’s airport and
airspace simulation model, the airport delay simulation model
(ADSIM), and the runway delay simulation model (RDSIM). Each of
these tools uses discrete event-based simulations to analyze operations.
As with most simulations, these tools apply an infrastructure of nodes
and links to define the airfield and airspace configurations, a set of
rules for how aircraft are to operate within the infrastructure, and a set
of discrete events, in particular the arrival and departure of aircraft
within the infrastructure, to simulate the environment.
These programs generate a series of standard reports detailing
the flights simulated, along with aggregated statistics, describing
the capacity of the system, delays encountered by flights, and any
rule violations or conflicts that may have occurred. They also prepare extended reports which compile delay statistics by hour for the
various runway-use configurations for arrivals, departures and
total operations. These reports can be output in both tabular and
graphical format.
537
538
Special Topics in Airpor t Planning and Design
There are various other computer simulation models with varying degrees capabilities including ATAC’s SIMMOD, the Preston
Group’s total airport and airspace modeler (TAAM) and smaller
generic simulation programs such as ARENA that may be applied to
the airport environment. The reader is encouraged to read these
products’ promotional materials and/or user guides to gain a greater
appreciation of these models.
Gate Capacity
Gate capacity can be defined as the maximum number of aircraft that
a fixed number of gates can accommodate during a specified interval
of time when there is a continuous demand for service. Gate capacity
can be calculated as the inverse of a weighted-average gate occupancy time of all aircraft being served. For example, if an aircraft
occupies a gate for an average of 30 min, the capacity of the gate
equals two aircraft per hour.
The factors that affect gate capacity are as follows:
1. The number and type of gates available to aircraft.
2. The mix of aircraft demanding apron gates and the gate occupancy time for various aircraft.
3. The percentage of time gates may be used, which reflects the
fact that time is required to maneuver aircraft into and out of
gate positions and the delay often restricts the amount of time
actually available for aircraft gate occupancy.
4. Restrictions in the use of any or all gates.
Type of gate refers to its ability to accommodate a large, medium,
or small aircraft. Normally gates at an airport are designated as widebodied aircraft gates, narrow-bodied aircraft gates and commuteraircraft gates. The mix of aircraft refers primarily to size but also the
required gate occupancy time. Very large aircraft require certain types
of gates in order to process passengers. Time is spent maneuvering at
a gate and therefore the gate utilization may not be 100 percent of the
time. If the gate occupancy time includes the time to maneuver at
gate positions, as well as the normal processing times to load and
unload passengers, to fuel and inspect the aircraft, perform cabin
service and other routine service, then the utilization will approach
100 percent. Occupancy times vary depending on the size of aircraft
and whether it is an originating, turnaround, or through flight. The
gate occupancy times expected by aircraft manufacturers are usually
given in publications; however, this will vary with each airline and
their operating procedures at different stations or airports. Often
schedules or lateness of arrivals will result in much greater occupancy times than normally required.
Airport Airside Capacity and Delay
Analytical Models for Gate Capacity
The basis of gate capacity analysis is that the gate time demanded by
aircraft should be less than or equal to the gate time available for these
aircraft. Two analytical models have been developed for determining
the capacity of gates at an airport. One model assumes that all aircraft
can use all the gates available at an airport. This is termed an unrestricted gate-use strategy. The other model assumes that aircraft of a
certain size or airline can only use gates that were specifically designed
for these aircraft or airline. This is called a restricted gate use strategy.
Both of these models are described and most situations encountered
in practice may be approached through one of the two models.
When there are no restrictions on the use of gates, that is, all aircraft can use all the gates, the capacity of the gates Cg can be derived
as follows:
Gate time supplied ≥ gate time demanded:
µkNk ≥ E(Tg)Cg
where
(12-19)
µk = gate utilization factor, or the percentage of time in an
hour that the gates of type k may be used by aircraft of
type i
Nk = number of k type gates available to aircraft of type i
E(Tg) = expected value of the gate occupancy time demanded
by aircraft which can use gate type k
Cg = capacity of the gates of type k in aircraft per hour
The expected value of the gate occupancy time E(Tg) is found from
the following expression:
E(Tg) = ∑miTgi
(12-20)
where mi is the percentage of type i aircraft in the fleet mix using the
gates at airport, and Tgi is the gate occupancy time required for aircraft of type i at the airport.
The use of these equations is illustrated for unrestricted gate use
in Example Problem 12-12.
Example Problem 12-12 An airport has four gates available to all aircraft. The aircraft mix at the airport in the peak hour consists of 30 percent type A, 50 percent
type B, and 20 percent type C aircraft. Type A aircraft require a gate occupancy
time of 60 min, type B require 45 min, and type C require 30 min. Normally,
due to the distribution of demand, the maximum gate utilization which can
be expected is 70 percent. It is required to find the capacity of the gates at this
airport to process aircraft.
From Eq. (12-19) we have
0.70(4)(60) ≥ [0.3(60) + 0.50(45) + 0.20(30)]Cg
539
540
Special Topics in Airpor t Planning and Design
which reduces to
Cg = 3.6 aircraft per hour
It should be observed that, since every aircraft at a gate entails two operations, an arrival and a departure, the hourly capacity of the gates could also be
expressed as 2(3.6) = 7.2 operations per hour. Also if the gate utilization factor is
equal to 1, then the ultimate capacity of the gates becomes equal to 5.2 aircraft
per hour.
For restricted gate use, the mix of gates and the mix of aircraft
using the airport may not be the same. Therefore, it is necessary to
find the gate capacity of each type of gate and then determine the
overall capacity of the airport based upon gate capabilities as the
minimum capacity gate, capacity of any type gate. Mathematically,
this becomes
Cg = min(Cgk)
(12-21)
The use of the above analysis for restricted gate use is shown in
Example Problem 12-13.
Example Problem 12-13 An airport has 10 gates available for aircraft. These gates
are restricted in the types of aircraft which can be accommodated. The five
type I gates can accommodate any type of aircraft, the three type II gates cannot
accommodate a type A aircraft, and a type III gate can only accommodate a
type C aircraft.
The mix and the gate occupancy times of the aircraft using the airport in the
peak hour is the same as in Example Problem 12-13. The gate utilization factor
is 1.0.
Determine the capacity of the gates to process aircraft at this airport.
The relationship shown in Eq. (12-19) must be solved for each type of gate.
There are 5 gates available to type A, 8 for type B, and 10 for type C aircraft.
Solving Eq. (12-19) for each gate type yields
1.0(5)(60) ≥ 0.3(60)CgI
CgI = 16.67 aircraft per hour
1.0(8)(60) ≥ [0.3(60) + 0.5(45)]CgII
CgII = 11.85 aircraft per hour
1.0(10)(60) ≥ [0.3(60) + 0.5(45) + 0.2(30)]CgIII
CgIII = 12.90 aircraft per hour
Therefore, the type II gates restrict the aircraft capacity of the airport from
Eq. (12-21)
Cg = min(16.67, 11.85, 12.90) = 11.9
Therefore, with this mix of aircraft demanding gates at the airport, the gate
mix restricts the airport capacity to 11.9 aircraft per hour or 23.8 operations per
hour.
Airport Airside Capacity and Delay
It should be noted that only with this capacity is the gate time supplied
greater than or equal to the gate time demanded. This is shown as
Gate time supplied ≥ gate time demanded
1.0(10)(60) ≥ [0.3(60) + 0.5(45) + 0.2(30)](11.9)
600 ≥ 554 as required
As described in this chapter, airport planning and design with
respect to capacity is a critical and complex process. While this chapter focused on the analytical fundamentals of estimating capacity,
planners should take careful consideration into estimating capacity
from both an analytical and empirical perspective, ideally applying
some form of simulation model. It is understood that there is also a
balance that must be maintained by the airport planner between the
amount of time and budget available to do capacity studies. Some
airports with relatively simple airfield configurations and relatively
small planning budgets may be sufficiently served with a basic analytical model, or more simply referencing FAA approximation charts.
On the other hand, large-scale complex projects should dedicate sufficient resources to properly and comprehensively analyzing capacity
and projected delays as part of the planning process. While such
involvement may be expensive, the investment made in properly
designing for appropriate capacity may very well avoid much higher
costs associated with developing infrastructure that cannot accommodate those who use it.
References
1. “A Flexible Model for Runway Capacity Analysis,” W. E. Weiss, Master’s
Thesis, Massachusetts Institute of Technology, Cambridge, Mass., June 1980.
2. Air and Ground Delay Study: Impact of Increased Operations at Lindbergh Field,
Report No. AOR-89-01, Operations Research Office, Federal Aviation
Administration, Washington, D.C., September 1989.
3. Airport Capacity, Airborne Instruments Laboratory, Report No. BRD-136, Federal
Aviation Agency, Office of Technical Services, Department of Commerce,
Washington, D.C., June 1963.
4. Airport Capacity and Delay, Advisory Circular AC 150/5060-5, Federal Aviation
Administration, Washington, D.C., 1983.
5. Airport Ground Access, Report No. FAA-EM-79-4, Federal Aviation
Administration, Washington, D.C., October 1978.
6. Airport System Capacity, Strategic Choices, Special Report, No. 226, Transportation
Research Board, Washington, D.C., 1990.
7. Air Traffic Control Handbook, Order No. 7110.65G, Federal Aviation
Administration, Washington, D.C., March 1992.
8. “A Methodology for Airport Capacity Analysis,” S. L. M. Hockaday and
A. Kanafani, Transportation Research, Vol. 8, 1974.
9. Aviation System Capacity Plan 1991–92, Report No. DOT/FAA/ASC-91-1, U.S.
Department of Transportation, Federal Aviation Administration, Washington,
D.C., 1991.
10. Chicago Delay Task Force Technical Report, Vol. II Model Validation and Existing
Airspace/Airfield Performance, Landrum and Brown Aviation Consultants,
Chicago, Ill., April 1991.
541
542
Special Topics in Airpor t Planning and Design
11. Critique of the Aircraft Delay Curves in Techniques for Determining Airport Airside
Capacity and Delay, C. T. Ball, Graduate Report No. UCB-ITS-GR-78-1, Institute of
Transportation Studies, University of California, Berkeley, Calif., August 1978.
12. FAA Report on Airport Capacity, Report No. FAA-EM-74-5, Federal Aviation
Administration, Washington, D.C., 1974.
13. Future Development of the U.S. Airport Network, Preliminary Report and Recommended
Study Plan, Transportation Research Board, Washington, D.C., 1988.
14. Measuring Airport Landside Capacity, Special Report, No. 215, Transportation
Research Board, Washington, D.C., 1987.
15. Models for Estimating Runway Landing Capacity with Microwave Landing Systems
(MLS), V. Tosic and R. Horonjeff, Special Report, National Aeronautics and Space
Administration, Ames Research Center, Moffett Field, Calif., September 1975.
16. Models for Runway Capacity Analysis, R. M. Harris, MITRE Corporation, Report No.
FAA-EM-73-5, Federal Aviation Administration, Washington, D.C., May 1974.
17. Model Users’ Manual for Airfield Capacity and Delay Models, C. T. Ball, Report
No. FAA-RD-76-128, Federal Aviation Administration, Washington, D.C.,
November 1976.
18. National Plan of Integrated Airport Systems (NPIAS) 1990–1999, Federal Aviation
Administration, Washington, D.C., 1991.
19. O’Hare Delay Task Force Study, Executive Summary and Technical Report,
Chicago O’Hare International Airport, Report No. FAA-AGL-76-1, Federal
Aviation Administration, Washington, D.C., July 1976.
20. Procedures for Determination of Airport Capacity, Report No. FAA-RD-73-111,
Vols. 1 and 2, Interim Report, Federal Aviation Administration, Washington,
D.C., April 1973.
21. Reauthorizing Programs of the Federal Aviation Administration, Future Capacity
Needs and Proposals to Meet Those Needs, Subcommittee on Aviation, Committee
on Public Works and Transportation, House of Representative Report No. 101-37,
US House of Representatives, Washington, D.C., 1990.
22. SIMMOD: The Airport and Airspace Simulation Model, Reference Manual, Release 1.1,
Federal Aviation Administration, Washington, D.C., October 1990.
23. South Florida Supplemental Airport Study, H. True, S. Wolf, and D. Winer,
Operations Research Service, Federal Aviation Administration, Washington,
D.C., February 1991.
24. Supporting Documentation for Technical Report on Airport Capacity and Delay
Studies, Report No. FAA-RD-76-153, Federal Aviation Administration,
Washington, D.C., June 1976.
25. Technical Report on Airport Capacity and Delay Studies, Final Report, Report No.
FAA-RD-76-153, Federal Aviation Administration, Washington, D.C., June 1976.
26. Techniques for Determining Airport Airside Capacity and Delay, Report No. FAARD-74-124, Federal Aviation Administration, Washington, D.C., June 1976.
27. Terminal Area Forecasts, Fiscal Years 1991–2005, Report No. FAA-APO-91-5,
Federal Aviation Administration, Washington, D.C., July 1991.
28. Upgraded FAA Airfield Capacity Model, Vol. I: Supplemental User’s Guide, W. J.
Swedish, The MITRE Corporation, Report No. FAA-EM-81-1, Vol. I, Federal
Aviation Administration, Washington, D.C., February 1981.
29. Upgraded FAA Airfield Capacity Model, Vol. II: Technical Descriptions of Revisions,
W. J. Swedish, The MITRE Corporation, Report No. FAA-EM-81-1, Vol. II,
Federal Aviation Administration, Washington, D.C., February 1981.
30. Validation of the SIMMOD Model, Final Report, J. C. Bobick, ATAC Corporation,
Mountain View, Calif., December 1988.
31. National Airspace System: DOT and FAA Actions Will Likes Have a Limited
Effect on Reducing Delays during Summer 2008 Travel Season, US GAO
Publication GAO-012- 934T, Washington, D.C. 2008.
CHAPTER
13
Finance Strategies
for Airport Planning
Introduction
This chapter is designed to provide the airport planner and engineer
with some of the fundamental strategies available to finance large scale
planning and design projects. Due to the rules associated with many
Federal, state, and local programs in the United States, strategies for
funding large capital programs are both different and exclusive from
funding the day-to-day operations of an airport. Thus, the focus of this
chapter is on capital programs, including grants, bond strategies, and
private investment, and not on operational revenue strategies, more
germane to airport management.
Background
In the very early years of aviation, airport ownership was vested
almost entirely in private hands. State and federal financial participation in airport development was virtually nonexistent. The Depression
of the 1920s witnessed a collapse in private investments in airports
and gave rise to public ownership. As of 2008, the vast majority of
airports within the United States are still privately owned and operated, although most of the overall aviation activity, and virtually all
commercial airline activity, operates at publicly owned airports. Internationally, many airports are still operated by their respective federal
governments, although, many international airports have become
owned and operated by for-profit private entities.
Public ownership in airports is vested in a number of different
types of government levels, including municipalities, counties, and
state ownership. The largest percentage of the 100 busiest airports in
the United States is operated by an “authority.” An authority is an independent, politically appointed entity, typically comprised of representatives from the municipalities, counties, and/or states in which the
airport is located.
543
544
Special Topics in Airpor t Planning and Design
Although both the federal and state governments may have provisions which affect the airport, it is the decision of the airport owner, called
the airport sponsor, which ultimately determines the development of the
airport.
Airport improvements are financed in a variety of ways including
federal grants, state grants, airport bonds, and private investment. In
addition, capital improvements of a minor nature have been financed
from accumulated surpluses from airport revenues.
Federal Funding Programs in the United States
Until l933, airports for civil use were developed mainly through
investments by municipalities and private sources. The Depression
was largely responsible for the first substantial federal participation
in the development of civil airports. The bulk of the funds provided
from l933 until the beginning of World War II were through workrelief programs. The first program was under the Civil Works Administration (CWA). In the fall of l933, the CWA provided more than
$15 million for airport construction, with most of the money going to
smaller communities.
In l934, the CWA was succeeded by the Federal Emergency Relief
Administration (FERA). This agency provided over $17 million for
the development of 943 airport projects.
The administration of federal aid for airports was taken over in
l935 by the Works Progress Administration (WPA). The WPA spent
$323 million for airport construction in the United States and it was
under this program that contributions by municipalities were encouraged and a pattern of cost sharing emerged. The local contributions
amounted to about $ll0 million.
Another federal program contributing to airport development
in the 1930s was the Public Works Administration (PWA) which
made loans or grants amounting to almost $29 million, primarily to
municipalities.
Prior to the start of World War II the federal government spent a
total of about $384 million for airport development under the four
programs of CWA, FERA, WPA, and PWA, however, it must be recognized that these were primarily work-relief programs and provided
no basis for federal support in times of a normal economy.
During World War II the federal government, through the Civil
Aeronautics Administration, spent $353 million for the development
of landing areas for military use. While the priority in this program
was attached to military requirements, the needs of postwar civil aviation were considered in the location and construction of these facilities. During the same period the federal government, through the
CAA, spent over $9 million for the development of airports solely for
civil use. These two programs are referred to as defense landing area
(DLA) and development of civil landing areas (DCLA). The DLA and
Finance Strategies for Airport Planning
DCLA programs were independent of the airports constructed by the
war and navy departments. After the war some 500 military airports
were declared surplus and turned over to cities, counties, and states.
This is the principal reason that today’s public ownership is vested in
local authorities.
The Federal Aid to Airports Program
At the end of World War II interest was renewed in establishing a
federal program for monetary aid for airport development. A resolution was introduced in Congress (H.R. 598, 78th Congress) requiring
the Civil Aeronautics Administration to make a survey of airport
needs and prepare a report on the subject. These recommendations
formed the basis of the Federal Aid to Airports programs, as written
in the Federal Airport Act of l946 (Public Law 79-377). Appropriations of $500 million over a 7-year period were authorized for projects
within the United States plus $20 million for projects in Alaska,
Hawaii, Puerto Rico, and the Virgin Islands. In l950 the 7-year period
was extended for an additional 5 years (Public Law 81-846). However, annual appropriations approved by Congress were much less
than the amounts authorized by the act.
The original act provided that a project shall not be approved for
federal aid unless “sufficient funds are available for that portion of
the project which is not to be paid by the United States.”
Local governments often required 2 to 3 years to make arrangements for raising funds and most of the larger projects were financed
locally through the sale of bonds. This method of financing required
legislation at the local level and, in some cases, also at the state level.
General obligation bonds normally required approval by the electorate.
Programs to inform the public on the need for airport improvement
must be carefully planned and executed. Thus, after the completion
of these events, local governments frequently found that sufficient
federal funds were not appropriated to match local funds, and the
projects were delayed. Another complaint of local governments had
been that Congress failed to fulfill its obligation, since the amount
appropriated by Congress fell far short of the amount authorized by
the Federal Airport Act. These deficiencies as well as other matters
were incorporated in a new bill (S. l855) and hearings were held
before the subcommittee of the Committee on Interstate and Foreign
Commerce of the U.S. Senate in l955. Representatives of the Council
of State Governments, the American Municipal Association, the
National Association of State Aviation Officials, airport and industry
trade associations, and individuals were unanimous in the feeling
that air transportation had reached a stage of maturity where many
airports were woefully inadequate and greater financial assistance
from the federal government would be required to meet the current
needs of aviation. After much debate, the bill was approved by the
President (Public Law 84-211).
545
546
Special Topics in Airpor t Planning and Design
This amending act made no change in the basic policies and purposes expressed in the original act. There were no changes in the
requirements with respect to the administration of the grants authorized, such as the distribution and apportionment of funds, eligibility
of the various types of airport construction, sponsorship requirements,
etc. The primary purpose of the act was to provide provisions granting substantial annual contract authorization in specific amounts over
a period of four fiscal years. Airport sponsors were thus furnished
assurance that federal funds would be available at the time projects
were to be undertaken.
This law provided $40 million for fiscal year l956 and $60 million
for each of fiscal years l957, l958, and l959 for airport construction in
the continental United States. It also provided $2.5 million in fiscal
year l956 and $3 million for the three succeeding fiscal years for airport construction in Alaska, Hawaii, Puerto Rico, and the Virgin
Islands. Besides the $42.5 million made available in fiscal year l956 by
Public Law 84-2ll, Congress approved an additional appropriation of
$20 million for airport projects.
In l958, the 85th Congress passed a bill (S. 3502) proposing to
extend the Federal Airport Act for 4 years at an annual funding rate
of $l00 million. This bill was vetoed by the President in September
l958 with a veto statement (S. 3502 Veto Statement), which stated
in part:
I am convinced that the time has come for the federal government to
begin an orderly withdrawal from the airport grant program. This conclusion is based, first, on the hard fact that the government must now
devote the resources it can make available for the promotion of civil
aviation programs which cannot be assumed by others, and second, on
the conviction that others should begin to assume the full responsibility
for the cost of construction and improvement of civil airports.
In the 86th Congress, much debate involved a significant increase
in the federal airport program. Two bills, one introduced in the House
($297 million over a 4-year period) and the other in the Senate
($465 million for a 4-year period), together with the President’s recommended bill for a 4-year program of $200 million, were finally
merged into a 2-year continuation of the existing aid program at
$63 million per year (Public Law 86-72).
Significant changes were the removal of the territorial status from
Hawaii and Alaska which had been admitted as states and the exclusion of automobile parking and certain portions of airport building
improvement costs as allowable costs.
A 3-year continuation of the federal aid program providing
$75 million annually was enacted by the 87th Congress (Public
Law 87-255). The provisions of the bill were very similar to those
of Public Law 86-72. One new feature of the legislation was that it
Finance Strategies for Airport Planning
provided the administrator of the FAA with a discretionary fund
of $7 million from the $75 million for developing general aviation
airports to relieve congestion at high-density commercial airports.
Thus this legislation started the reliever airport program. The
Federal Airport Act was again amended in 1964, authorizing the
expenditure of $75 million for fiscal years l965 to l967 (Public
Law 88-280). The final amendment was accepted in l966, authorizing the continuation of the expenditure of $75 million for fiscal
years l968 to 1970 (Public Law 89-647). This marked the end of the
Federal Airport Act, as the Airport and Airway Development Act
of l970 became law in l970.
During the 24 years of airport funding under the Federal Airport
Act, a total of $l.2 billion has been appropriated by the federal government for improvements at 23l6 airports involving almost 8000
projects. Much of the capital infrastructure of airports still in existence were funded by, and adhere to the terms of the Federal Aid to
Airports program.
The Airport Development Aid Program
Because of the rapidly growing requirements for modernizing the air
traffic control system and airport expansion, neither the federal government nor the local authorities were able to fund capital improvements badly needed for the growth of aviation. The FAA needed
more money in its budget to accelerate the implementation of a
program to modernize the air traffic control system. The $75 million
authorized annually by the Federal Aviation Act, together with local
matching funds, fell far short of the needs of the local airport authorities to meet the current and projected growth of airport traffic. Cities
were unable to raise sufficient funds at the local level to meet the rising costs of airport construction. The Federal Aviation Act of l946 was
supported by general rather than user tax revenues and therefore it
had to compete annually with other government programs for scarce
federal dollars. The increased competition for fewer dollars resulted
in delay and postponement of airport construction throughout the
nation. As a result of this situation, aviation organizations representing
airport owners, airlines, pilots, and general aviation aircraft owners
joined in pressing for more funds for airports and airways and the
establishment of a trust fund similar to that for the national highway
program. Several bills were introduced in the House and Senate to
enact legislation which would remedy the deficiencies in the Federal
Airport Act of l946 (S. 1637, S. 2437, S. 2651). After much debate including the question of whether airport terminal buildings should be
included in the legislation (initially they were not), Public Law 9l-258
was signed into law in May l970. As stated in Chap. 1, the law consisted of two parts, referred to as Titles I and II. Title I was known as
the Airport and Airway Development Act of l970, which replaced the
547
548
Special Topics in Airpor t Planning and Design
Federal Airport Act of l946. Title II was known as the Airport and
Airway Revenue Act of l970, and it provided the excise taxes required
to furnish the resources necessary to carry out the Title I programs
through l980. These excise taxes provided the revenues to fund the
programs under the act and were deposited in the Airport and
Airway Trust Fund established by the act.
Title I of the original act provided for $250 million annually for
the “acquisition, establishment, and improvement of air navigational
facilities” and security equipment required by the sponsor for fiscal
years 1971 through l980. For airport assistance, the Airport Development Aid Program (ADAP) initially authorized a total of $2.5 billion
for the l0-year period. The act further specifically authorized
$250 million annually through fiscal year l973 and $275 million each
for fiscal years l974 and l975 for airports served by air carriers and
general aviation airports which relieve high-density air carrier airports. Also authorized were $30 million annually through fiscal year
l973 and $35 million each for fiscal years l974 and l975 for all other
general aviation airports (Public Law 93-44). Later amendments
(Public Law 94-353) raised the program level to range from $500 to
$610 million annually through 1980. The Aviation Safety and Noise
Abatement Act (Public Law 96-193) further raised the final-year program to $667 million. These amendments provided $435 to $539 million
annually for airports serving all segments of aviation and $65 to
$95 million annually for general aviation airports. The act also authorized the issuance of planning grants for the preparation of airport
system plans and airport master plans. The Planning Grant Program
(PGP) was designed to promote the effective location and development of publicly owned airports and to develop a national airport
system plan. System plans were prepared by state and regional agencies to formulate air transportation policy, determine facility requirements needed to meet forecast aviation demand, and establish a
framework for detailed airport master planning. Airport master
plans, which were developed by the airport owner, focused on the
nature and extent of the development required to meet the future
aviation demand at specific facilities.
The funds that were authorized for airport development for the
several classes of airports were apportioned to air carrier and general
aviation airports. In the final amended form of the law, two-thirds of
the air carrier and commuter service funds were made available to air
carrier airports based upon the number of annual enplaned passengers. These were termed entitlement funds. The remaining monies
were placed in a discretionary fund, of which $15 million annually
was apportioned to commuter service airports. Air carrier airports
serving aircraft heavier than 12,500 lb were authorized to receive
between $150,000 and $10 million annually. Airports serving aircraft
weighing less than 12,500 lb were to receive not less than $50,000
annually. Of the funds appropriated for general aviation and general
Finance Strategies for Airport Planning
aviation reliever airports, $15 million annually was apportioned to
reliever airports. Seventy-five percent of the remaining funds was
allocated to the states on the basis of population and area; 1 percent
was allocated to Puerto Rico, Guam, the Virgin Islands, American
Samoa, and the Trust Territories of the Pacific Islands and was distributed by the Secretary of Transportation.
The maximum federal grant for any specified project varied from
50 to 90 percent of the total eligible project costs over the life of the
act, depending upon the type of project being considered for funding.
A maximum of 75 percent of the allowable project cost was allowed
for airports in areas that enplaned 0.25 percent or more of the total
annual passengers enplaned by air carriers certified by the Civil
Aeronautics Board. These airports were called the large and medium
air traffic hub airports. A maximum of 90 percent of the allowable
project cost was allowed for airports in areas that enplaned less than
0.25 percent of the total annual passengers, for small air traffic hub
and nonhub airports, and for general aviation airports.
The original act specifically prohibited the use of federal funds for
automobile parking facilities or airport buildings except those parts
“intended to house facilities or activities directly related to the safety
of persons at the airport.” However, amendments to the act in 1976,
(Public Law 94-353) provided federal funding for the non-revenueproducing public areas of terminal facilities required for the processing
of passengers and baggage. In this case the federal share was limited to
50 percent of the project costs, and the airport could not spend more
than 60 percent of its enplanement funds on such development.
There was no state apportionment for planning grant funds. The
Secretary of Transportation prescribed the regulations governing the
award and administration of these grants. When the program first
began, the federal government provided up to two-thirds of the cost
of planning grant projects. However, amendments to the act in 1976
increased this share to 75 percent of the cost of airport system plans,
90 percent of the cost for master plans at general aviation airports, and
a range from 75 to 90 percent of the cost for master plans at air carrier
airports, depending upon the number of enplaned passengers.
In administering the Airport and Airways Development Act, the
FAA established, in detail, the types of improvements which were
eligible for federal aid under the act. In general, items that were eligible included land acquisition, paving and grading, lighting and electrical work, utilities, roads, removal of obstructions to air navigation,
fencing, fire and rescue equipment, snow removal equipment, terminal-area development, and physical barriers and landscaping for noise
attenuation.
Separate buildings for airport emergency, snow removal, and
firefighting equipment were eligible but administration buildings
serving air commerce or general aviation were not eligible. Buildings used exclusively for the handling of cargo were also ineligible.
549
550
Special Topics in Airpor t Planning and Design
The non-revenue-producing public-use areas of terminal facilities
became eligible for funding in 1976 (Public Law 94-353) if these areas
were “directly related to the movement of passengers and baggage in
air commerce within the boundaries of the airport.”
Roads and streets were eligible if they were within the boundary
of the airport and were needed for the operation and maintenance of
the airport, or were directly related to the movement of passengers
and baggage.
Each eligible project was evaluated separately. It was rated on the
basis of the aeronautical necessity of the airport, volume and character
of traffic, and type of work included in the project. These ratings established a priority score for each increment of work in any one state and
were used to program the funds allocated to that state. The ratings
were based on such factors as safety, efficiency, and convenience.
A community interested in obtaining federal aid contacted the
Airports District Office (ADO) of the FAA in the geographic area in
which the airport was located. In states which required that all federal aid be channeled through the state, submission of a request for
aid was made through the state aeronautical agency.
If the project qualified for aid, if there were sufficient funds, and
if the project was found by the Secretary of Transportation to be
acceptable from the standpoint of its economic, social, and environmental effects on the community, then the sponsor was notified that
a tentative allocation of funds had been made for part of or all of the
items listed in the request. The tentative allocation was an indication
that funds had been placed in reserve pending the completion of
arrangements for necessary financing, land acquisition, and preparation of plans, specifications, and contract documents.
Upon submitting detailed plans and specifications with a project
application and upon approval of the FAA, the sponsor secured bids
from contractors and made recommendations for the award of the
contracts. At this time the sponsor also formally accepted federal aid
and the obligations connected therewith by executing what was
known as a “grant agreement.” The execution of the grant agreement
legally bound the community to fulfill the obligations (sponsors’
assurances) set forth in the project application. Some of the sponsor’s
important obligations included:
1. The sponsor would operate the airport for the use and benefit of the public, on fair and reasonable terms without unjust
discrimination.
2. It would keep the airport open to all types, kinds, and classes
of aeronautical use without discrimination between such
types, kinds, and classes.
3. It would operate and maintain in a safe and serviceable
condition the airport and all facilities thereon which are
Finance Strategies for Airport Planning
necessary to serve aeronautical uses other than facilities
owned or controlled by the United States.
4. It would make every effort to maintain clear approaches to
the runways.
5. It would not charge government owned or military aircraft
for the use of runways and taxiways unless the use was
substantial.
6. These obligations would remain in effect for not more
than 20 years.
The authority to issue grants under this act expired in 1981.
During the 11-year period under this legislation, 8809 grants totaling
$4.5 billion were approved for airport planning and development at
over 1800 airports. This was about four times greater than the total
amount provided by the Federal Airport Act of l946. Over 6700 of
these grants were made under the Airport Development Aid Program, and almost 2000 of these grants were made under the Planning
Grant Program.
In 1982, Congress enacted the Airport and Airway Improvement Act (Title V of the Tax Equity and Fiscal Responsibility Act of
1982, Public Law 97-248). This act continued to provide funding for
airport planning and development under a single program called
the Airport Improvement Program (AIP). The act also authorized
funding for noise compatibility planning and implementation of
noise compatibility programs contained in the Noise Abatement
Act of 1979 (Public Law 96-193). It required that to be eligible for a
grant, the airport must be included in the National Plan of Integrated Airport Systems (NPIAS). The NPIAS, the successor to the
National Airport System Plan (NASP), is prepared by the FAA and
published every 2 years and it identifies public-use airports considered necessary to provide a safe, efficient, and integrated system of airports to meet the needs of civil aviation, national defense,
and the U.S. Postal Service.
Projects eligible for funding under this legislation were restricted
to planning, development, and noise compatibility projects at or associated with public-use airports, including heliports and seaplane
bases, which were defined as airports open to the public and publicly
owned, or privately owned but designated by the FAA as a reliever
airport, or privately owned and having scheduled service and at least
2500 annual enplanements.
Airports were defined in five categories: commercial service airports, primary airports, cargo service airports, reliever airports, and
other airports. Commercial service airports are publicly owned airports which enplaned at least 2500 passengers annually and received
scheduled service. Primary service airports are commercial service
airports which enplaned at least 10,000 passengers annually. Cargo
551
552
Special Topics in Airpor t Planning and Design
service airports are airports served by aircraft providing air transportation of property only, including mail, with an aggregate annual
aircraft landed weight in excess of 100,000,000 lb. Reliever airports
are airports in metropolitan areas designated by the FAA as having
the function of relieving congestion at large commercial service airports by providing alternative landing areas for general aviation
aircraft and which provided more general aviation access to the
community. Other airports are the remaining airports, commonly
referred to as general aviation airports.
The allocation of funds under the AIP was also defined in the
legislation such that these funds are distributed between apportioned
and discretionary funds. As amended by the Airport and Airway
Safety, Capacity, Noise Improvement and Intermodal Transportation
Act of 1992, of the total funds available not more than 44 percent is
apportioned as entitlements to primary airports and 3.5 percent is
apportioned as entitlements to cargo service airports. Additionally,
12 percent of the total funds is apportioned for states and insular
areas. There is a separate apportionment for airports in Alaska, and
2.5 percent is apportioned to the Military Airport Program for current
and former military airfields, to enhance the capacity of the national
transportation system by enhancement of airport and air traffic control systems in major metropolitan areas. The remaining funds are
designated as discretionary funds, which are required to be used so
that of the total funds available a minimum of 10 percent is to be used
for reliever airports, 12.5 percent for noise compatibility projects,
2.5 percent for nonprimary commercial service airports, and 0.5 percent
for integrated system plans for states, regions, or metropolitan areas.
Of the remaining discretionary funds 75 percent are to be used for
projects to preserve and enhance capacity, safety, and security and
projects carrying out noise compatibility planning programs at primary and reliever airports.
The federal share of the costs associated with integrated airport
system planning was limited to 90 percent. For individual airports,
the federal share of planning and airport development project costs
was limited to 75 percent at primary airports and 90 percent at all
other airports. The federal share of the costs of noise compatibility
projects was limited to 80 percent. The federal share of non-revenueproducing public-area terminal development costs at large, medium,
and small hub commercial service airports was limited to 75 percent.
The federal share of both revenue-producing and non-revenueproducing public areas in terminal buildings and non-revenueproducing parking lots at nonhub commercial service airports was
limited to 85 percent.
The Airport and Airway Improvement Act has been amended
several times resulting in significant changes in the provisions of the
act and in authorized appropriations. These amendments are included
Finance Strategies for Airport Planning
in the Continuing Appropriations Act of 1982, the Surface Transportation Assistance Act, the Airport and Airway Safety and Capacity
Expansion Act of 1987, the Airway Safety and Capacity Expansion
Act of 1990 the Airport and Airway Safety, Capacity, Noise Improvement and Intermodal Transportation Act of 1992, the Wendell H.
Ford Aviation Investment and Reform Act for the Twenty-First
Century (AIR-21), and Century of Aviation Reauthorization Act
(Vision 100) of 2003. Each of these amendments altered, and often
increased, the annual congressional authorized of AIP funding levels
and the terms to which they are appropriated. In addition, the terms
to which the Airport and Airway Trust Fund is contributed has been
modified with the above amendments. Figure 13-1 illustrates the
annual authorizations and appropriations of AIP funding since its
inception in 1982.
In 2007, the final year of the amendments associated with Vision
100, approximately $3.4 billion in AIP funding was authorized.
Appropriated funds from these authorizations were allocated through
two primary funding categories: entitlements and discretionary funding (Table 13-1).
AIP entitlements to a primary airport are based on the number of
an airport’s categorization within the NPIAS and the airport’s annual
enplanement levels. In 2006, primary airports received annual AIP
entitlements ranging from $750,000 to more than $6 million, whereas
nonprimary entitlements, offered to nonprimary commercial service,
general aviation, and reliever airports, were typically $150,000 per
airport.
AIP discretionary funds are grants that may be applied for by airports to fund capital improvement projects, including infrastructure
$4.0
Funding (billions)
3.5
3.0
Authorized
Appropriated
Estimate of Amount to be Appropriated by Congress
2.5
2.0
1.5
1.0
0.0
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002*
2003
2004
2005
2006
2007
0.5
Fiscal Year
FIGURE 13-1 AIP annual authorizations and appropriations.
AIR-21
Vision 100
553
554
Aviation Taxes
Comment
Tax Rate
Passengers
Domestic passenger
ticket tax
Ad valorem tax
7.5% of ticket price (10/1/99 through 9/30/2007)
Domestic flight
segment tax
“Domestic Segment” = a flight leg
consisting of one takeoff and one
landing by a flight
Rate is indexed by the Consumer Price Index starting 1/1/02
$3.00 per passenger per segment during calendar year (CY) 2003
$3.10 per passenger per segment during CY2004
$3.20 per passenger per segment during CY2005
$3.30 per passenger per segment during CY2006
$3.40 per passenger per segment during CY2007
Passenger ticket tax
for rural airports
Assessed on tickets on flights
that begin/end at a rural airport.
7.5% of ticket price (same as passenger ticket tax)
Flight segment fee does not apply.
Rural airport: <100K enplanements during 2nd preceding CY, and either 1) not located within 75 miles
of another airport with 100K+ enplanements, 2) is receiving essential air service subsides, or 3) is not
connected by paved roads to another airport
International arrival
and departure tax
Head tax assessed on pax
arriving or departing for foreign
destinations (& U.S. territories)
that are not subject to pax ticket
tax.
Rate
Rate
Rate
Rate
Rate
Rate
is indexed by the Consumer Price Index starting 1/1/99
during CY2003 = $13.40
during CY2004 = $13.70
during CY2005 = $14.10
during CY2006 = $14.50
during CY2007 = $15.10
Rate is indexed by the Consumer Price Index starting 1/1/99
$6.70 international facilities tax + applicable domestic tax rate
(during CY03)
$6.90 international facilities tax + applicable domestic tax rate
(during CY04)
$7.00 international facilities tax + applicable domestic tax rate
(during CY05)
$7.30 international facilities tax + applicable domestic tax rate
(during CY06)
$7.50 international facilities tax + applicable domestic tax rate
(during CY07)
Flights between
continental U.S. and
alaska or hawaii
Frequent flyer tax
Ad valorem tax assessed on
mileage awards (e.g., credit cards)
7.5% of value of miles
Freight/Mail
Domestic cargo/mail
6.25% of amount paid for the transportation of property by air
Aviation Fuel
General aviation fuel
tax
Aviation gasoline: $0.193/gallon
Jet fuel: $0.218/gallon
Commercial fuel tax
$0.043/gallon
Source: Federal Aviation Administration.
TABLE 13-1
Airport and Airway Trust Fund Tax Schedule as of 2007
555
556
Special Topics in Airpor t Planning and Design
enhancements directly benefiting aviation activity, land acquisition,
noise mitigation, and planning studies. These funds are awarded to
those projects deemed most important for improving the national
airspace system. AIP discretionary funds typically may assume up to
80 percent of a project’s capital costs and 100 percent for certain noise
mitigation programs.
The Passenger Facility Charge Program
The years following the 1982 Airport and Airway Transportation Act
saw significant growth at a few of the nation’s airports, due to the
hub-and-spoke network strategies adopted by the nation’s commercial air carriers. As a result, the vast majority of AIP funding was
directed toward investment in these largest hub airports. This allocation of funding left relatively little assistance available to the smaller
airports who were in need of capital improvements and other planning activities.
With the goal of providing more funding available to the smaller
airports by allowing the larger airports to raise capital funding on an
individual basis, the federal government authorized a policy that
would allow airports to charge passenger facility charges (PFCs).
Through the Aviation Safety and Capacity Expansion Act of 1990,
airport operators were permitted to propose collecting a $1, $2, or $3
fee per enplaned passenger. Revenues from PFCs could be used for
airport planning and development projects eligible for AIP funding,
as well as for the preparation of noise compatibility plans and measures. The provision of PFC has allowed more AIP funds to be allocated to smaller airports with fewer annual enplanements.
The legislation also provided that at those commercial service airports in areas which enplaned at least 0.25 percent of the national
annual enplanements in any year, i.e., the large and medium hub airports.
The entitlement funds apportioned to the airport based upon passenger enplanements would be reduced by 50 percent of the revenue
obtained through the PFCs but these reductions of entitlement funds
would not exceed 50 percent of the apportioned funds. The legislation
directed that 25 percent of the revenues obtained through a reduction in these apportioned funds are to be placed in the AIP discretionary fund, of which one-half is to be used for small hub airports, and
75 percent is to be used to establish a Small Airports Fund. One-third
of the revenues in the Small Airport Fund is to be distributed to
general aviation airports and two-thirds to nonhub commercial
service airports.
The specific requirements imposed upon airports requesting
authority to impose passenger facility charges are contained in FAR
Part 158 [15].
In 2000, the passage of the Wendell H. Ford Aviation Investment
and Reform Act for the Twenty-First Century (AIR-21) increased the
Finance Strategies for Airport Planning
allocation of federal grant programs by increasing the amount of AIP
funding that may be released from the Airport and Airway Trust
Fund on an annual basis, and allowing PFCs to be set at $4.00 or $4.50.
As of 2006, nearly 525 commercial service airports in the United States
have participated in the PFC program, generating nearly $2.2 billion
in funding for approved capital projects.
The Vision 100 Act of 2003 extended the life of these programs
through 2007. As of 2008, a reauthorization of these programs has yet
to be passed. Up for debate are a number of issues including how to
best fund the Trust Fund and how to best disseminate the funds
among the nation’s airports, while also making investments in a
major modernization of the nation’s airspace system.
As airfares have declined, aviation activity outside of airlines has
increased, and aviation infrastructure has aged to the point of needing major reinvestment, there has been much debate that the current
model of funding the system strictly through airline passenger and
landing fees will be insufficient. Much of the debate is focused on the
seeking user-based fees from both commercial and general aviation
activity to fund the system, much to the consternation of the general
aviation community. Also, there has been some debate associated
with raising the allowable PFC from $4.50 to $7.00. This has brought
concern to commercial air carriers who feel that any additional fees
could hurt demand for service.
In addition, debate has surrounded the redistribution of funds
from the trust fund. While AIP and PFC funding have traditionally
favored the largest of airports, smaller airports that struggle to retain
air service, and general aviation airports that have no commercial air
service, have received less funding. Potential policies being debated
have considered significantly reducing the enplanement-based AIP
entitlement funding program, in favor of more discretionary grants.
As of publication of this text, these debates continue, leaving current
funding programs under continuing resolutions.
State and Local Participation in Financing
Airport Improvements
Airport development and aviation planning are a major concern in
most states. As of 2003, 30 U.S. states provided some formal financial
assistance for airport improvements. Increases in state financial support have been dramatic during the past several years. Data show
that expenditures by states for airports have risen from $59 million in
1966 [11] to over $450 billion in 2008 [22].
State sharing in airport development varies depending on
whether federal aid is involved and whether this aid is channeled
through a state aeronautical agency. Most states require that federal
557
558
Special Topics in Airpor t Planning and Design
funds be channeled through the state to local sponsors. In those states
where this is a requirement, the state normally contributes one-half of
the sponsor’s share of the project costs, which amounts to approximately one-quarter of the total project cost. If no federal aid is
involved, the state often contributes between 50 and 90 percent of the
project cost. In other states where revenues are obtained from user
taxes, formulas for apportioning the revenues are established.
States obtain the revenues to finance aviation and airport improvement projects from a variety of sources, including the general fund,
aviation fuel taxes, aircraft sales and use taxes, and other sources
including hangar rents and other property leases, and tax revenue.
Nine U.S. states participate in a federal “State Block Grant”
program. This program allows participating states to receive large
amounts of AIP funding for distribution among state airports and
better manage their aviation system and associated capital improvement plans.
Once state and local funding sources are considered, municipalities provide the remainder of the funds for airport improvements.
These funds have come from four principal sources: revenues generated at the airport, taxes for the support of local government as a
whole, sale of general obligation bonds, and sale of revenue bonds. In
the early years of aviation, the general tax fund was the principal
source of local funds, and it still is for small airports. The taxes levied
are not earmarked specifically for airport use but are the kind that are
normally imposed to operate most of the affairs of local government.
As long as the amount of funding is relatively small, this method of
financing has not met with much opposition from the citizens in
whose political jurisdiction the airport is located.
Bond Financing
As aviation grew and the amounts of funds required became large in
relation to other community expenditures, drawing funds from the
general tax fund became impractical, and municipalities had to resort
to the sale of bonds. Initially these were primarily general obligation
type. There were several reasons for resorting to this type of bond
financing. First, obligating the entire resources of a local government
to back the bonds resulted in much more favorable interest rates than
could be obtained by any other form of financing. Second, the projected revenues to be derived from the facility to be developed were
often insufficient to utilize any other method of financing.
General Obligation Bonds
As air transport continued to grow and mature, the requirements for
airport capital improvements also grew substantially. At the same
Finance Strategies for Airport Planning
time, communities were faced with an increased demand for schools,
streets, sewage disposal, and other public services. In many cases cities
either had reached or were reaching the statutory limit on the amount
of general obligation bonds which they could issue, and the cities
desired to reserve whatever remaining margin of bonding capacity
they had to carry out needed improvements that did not have the
revenue potential of airports.
General Airport Revenue Bonds
Airport financing through general obligation bonds still exists for
many smaller airports due to fact that these bonds are typically
financed at relatively low interest rates, depending on the credit
strength of the airport sponsor, lower issuance costs, and little coverage requirements.
Larger airports have moved away from general obligation bonds
in recent years, mostly due to the difficulty of receiving large funding
and risks associated with obligating the municipality. To overcome
the limitation of financing through the sale of general obligation
bonds, many communities raise funds through the sale of revenue
bonds whenever possible.
General airport revenue bonds (GARBs) are the most common
bonds issued for airport capital improvements. While interest rates
are generally higher for revenue bonds than they are for general
obligation bonds, the differential between the two has decreased
considerably since the first issuance of revenue bonds. Revenue
bond financing is most successful for those components of the airport
which are good revenue producers, such as terminal buildings and
parking garages. In addition revenues generated from airline rates
and charges, terminal concessions, and other leases contribute to the
financing of revenue bonds. GARBs allow for revenues generated
from the full spectrum of airport revenue sources to back capital
improvement projects, including airfield infrastructure, such as runways or taxiways.
Special Facility Bonds
Some facilities at an airport, such as hangars, hotels, and shopping
centers, have been financed through what are known as special facility
bonds. These bonds are issued either by the airport sponsor or a single
tenant to finance the construction of a single facility, such as a terminal,
terminal expansion, maintenance or cargo facilities, or airline ground
support facilities. Special facility bonds are backed by the revenue to
be generated by the facility or the facility sponsor. The risks associated with these bonds are directly correlated to the financial stability
of the sponsor, and as such, specialty facility bonds have become less
recommended, particularly for projects backed by the commercial air
carriers.
559
560
Special Topics in Airpor t Planning and Design
To overcome the risks of a single backer or to build facilities to be
used by multiple tenants, such as a consolidated rental car facility,
multitenant special facility bonds have been issued. These bonds are
backed by more than one sponsor, and typically have greater credit
strengths.
PFC Bonds
As the passenger facility charge (PFC) program has grown since its
inception in 1990, strategies have been employed to leverage either
current or future PFC revenues to fund capital improvements. These
strategies are known as PFC leveraging, or the issuance of PFC bonds.
There are a number of varieties of PFC leveraging, from the consideration of PFCs as revenue to pay all or part of existing GARB debt
service to issuing bonds that will be paid off solely by projected PFC
revenue.
CFC Bonds
Similar to PFCs, certain airport tenants assess customer facility
charges (CFCs) to generate revenue. This is most common with rental
car agencies. Leveraging these CFCs has been a strategy employed to
finance the construction of rental car facilities, particularly consolidated rental car facilities, shared by a number of tenants.
The tenant builds the facility on property that is leased from the
airport owner. One advantage of this type of airport financing is that
it relieves the community of all capital investment in the facility
except for utilities and access roads or taxiways. However, it does
require the community to commit the land on the airport for 25 to
30 years, the period normally required in a ground lease if the tenant
is to secure private financing.
Privatization of Airports
Privatization is a mechanism by which some level of airport management, operation, or ownership is transferred from the public sector to
the private sector. Its purpose is to introduce market competition into
the operation of airports and to relieve government of the financial
burden of providing the large investments required to maintain and
operate a system of airports. Proposals exist for the private involvement in airports in several ways including the outright transfer of
airport ownership, the leasing of the airport to private sector management firms, and the private development, ownership, and operation of a segment of an airport such as the terminal buildings. Several
examples of the various types of airport privatization ventures presently exist [4].
Although in the United States the privatization of airports has been
limited, in other countries privatization of airports is a significant
Finance Strategies for Airport Planning
issue because of the absence of a specifically designated revenue base
dedicated to financing aviation system improvements such as the
Airport and Airway Trust Fund. In these countries, investments in
aviation facilities compete with other public sector programs for limited funds. Given the significant level of financial investment required
to maintain an adequate aviation system and the pressures to limit
overall government expenditures, privatization is viewed as a mechanism to finance aviation system improvements and operations with
limited public-sector involvement. Recently, despite the slow proliferation, privatization efforts in the United States began again to
become more high profile in the early years of the twenty-first
century.
Proponents of airport privatization often argue that economic
market forces and profit motivation can stimulate private-sector
investments, resulting in the development of both new airports and
increased capacity at existing airports. Furthermore, it is argued that
privatization can lead to cost savings in the management and operation of the airport because of private-sector profit motivation, which
tends to lower costs and increase productivity. It is also argued that
private sector management and operation of airports can lead to revenue enhancement through market pricing strategies being employed
for airport airside and landside services. Market pricing strategies,
such as marginal cost pricing, often lead to a more efficient utilization
of airport resources and generate revenues necessary to increase
capacity in those aspects of airport operations which need capacity
enhancement. Furthermore, market pricing can be used to increase
revenue from the various commercial enterprises offering services at
the airport.
Proposals for the privatization of airports require the careful
consideration of several factors, the most fundamental of which is
that an airport is essentially a monopoly upon which airport users,
i.e., airlines and other aircraft operators, passengers, and shippers,
are highly dependent. For this reason regulatory safeguards must be
implemented with privatization that maintain freedom of access and
nondiscrimination among different groups of airport users, ensure
conformity with operating standards and agreements, and satisfy
both national and local air transportation policy [3].
Privatization of airports may be categorized as either full privatization or partial privatization. While full privatization is defined as
the outright sale of the airport to a private owner/operator, partial
privatization is less strictly defined. Partial privatization typically
implies the involvement in some manner or other of a private investment or management firm in airport operations and/or capital
improvement projects.
Partial privatization in airports typically involves major airport
tenants, such as airlines, concessionaires, private companies operating on the airport, or private airport management companies.
561
562
Special Topics in Airpor t Planning and Design
Privatized activities range from simple management contract services,
to developer financing, to capital investments and the operations
of facilities.
Private investment in capital projects may be structured in a number of ways. Two of the more common strategies involve some level
of private investment in the capital stage, followed by an operating
agreement for a set term. Under a build, operate, and transfer (BOT)
agreement, for example, private investment is used to construct and
operate a facility for a defined period of time. At the end of the term,
the facility becomes the ownership of the airport sponsor.
In a lease, build, and operate (LBO) agreement an airport sponsor is
allowed to receive the benefits of privatization without losing control
over airport facilities. An LBO agreement allows private investment to
build and manage an airport facility, while the property itself is leased
by the private company from the airport for a period of time.
Full privatization has seen much of its success internationally,
beginning with the privatization of several airports in the United
Kingdom in the mid-1980s. Major international private airport operators now own and manage airports in Europe, Asia, Australia, and
the Middle East, with limited additional airports owned and operated in North and South America.
As of the publication of this text, the latest large commercial service airport in the United States to undertake privatization efforts is
Midway Airport in Chicago.
Financial Planning
The financial plan for the capital improvements at an airport requires
a detailed analysis of projected traffic, costs, and revenues. At larger
airports significant portions of the capital costs of a project are recovered through revenues from the airlines, concessionaires, and other
tenants. The remainder is recovered through capital grants from federal and state sources. Since the airlines become long-term tenants
obligated to pay user fees and rents for the facilities utilized in conducting their operations, an evaluation of the conceptual alternatives
in the planning phases of a project should only be undertaken with
direct input from these users. The financial feasibility of a program
is in a large measure determined by the magnitude and reasonableness of the charges and rents paid by airport users and tenants. The
financing of general aviation airports continues to be a major problem
since the revenue base available is usually insufficient to support
significant capital improvements. Therefore, it is imperative that
the benefits of such airports to the community be carefully analyzed
so that other sources of financing can be demonstrated economically viable.
Finance Strategies for Airport Planning
The determination of the financial feasibility of a project is initiated with an agreement between the airport owners and airport users
defining the fiscal policies which will govern the setting of rates and
charges for the airport users. The basic process consists of a series of
steps, as defined below [21]:
1. Allocation of the capital costs of the project to the various cost
centers is established by airport management and airport
users. These cost centers are usually categorized as the airfield area, hangar and other operational support building
areas, terminal area, concessions area, and other areas of the
airport.
2. The net annual costs of the capital construction program
are projected, and these costs are assigned to the various
cost centers. These costs are amortized over the period
specified in the agreement between management and
users.
3. Projection and allocation of the net annual administrative,
operating, and maintenance costs to each of the cost centers are based upon a knowledge of past cost experience
and projections of these anticipated costs for the new
facility.
4. Conversion of the total annual capital and administrative,
operating, and maintenance costs to a schedule of the fees
and rents to be paid by the users of the facilities utilizes available forecasts of aircraft activity, passenger enplanements,
parking usage, and other relevant indices of projected airport
activity.
Recovery of capital costs requires that the total capital investment
in each cost center be determined. Projected costs in the airfield area
for runways, taxiways, apron ramps, and land acquisition and
improvement and in the terminal area for terminal building construction, land, and terminal support facilities must be ascertained and
assigned to the relevant cost center. It is essential that airport support
facilities such as access roads, service roads, sanitary and storm sewer
systems, electrical and mechanical systems, communication and
security services, emergency medical services, and crash, fire, and
rescue services be properly apportioned to the appropriate cost centers to eliminate imbalances in the determination of the facility costcenter revenue requirements, which may result in unreasonable rates
and charges. For projects where bond issues are utilized to finance
portions of the capital costs, the annual cost of debt service (i.e., principal, interest and the required reserve, called coverage) over the
recovery period must be included and assigned to the relevant cost
center category.
563
564
Special Topics in Airpor t Planning and Design
The anticipated costs of airport administration, operations, and
maintenance are assigned to each cost center on an annual basis.
These costs generally include all direct costs for salaries, materials,
supplies, and outside services and related indirect costs.
Terminal costs are divided by the terminal area. Often the location and degree of finishing in ticketing facilities, baggage facilities,
office space, and car rental space are taken into consideration to establish rental rates for the terminal building tenants.
Concession and other airport revenues will normally be applied
against the appropriate cost center and the net revenue recovery
requirements determined. Forecasts of landing weights are used to
determine the landing fees charged to the airlines to recover airfield
costs. Often the cost of the apron area is isolated as a separate cost
center, and ramp fees are established based upon the gate frontage
required by the airlines.
Concession area costs are derived from rentals paid and from
charging the concessionaire a percentage of the gross receipts. Usually the most significant concession cost center at a large airport is the
parking facility. Since the capital costs of a parking structure are considerable, these costs are usually assigned to the terminal-area cost
center. The administrative, operating, and maintenance costs of these
facilities are recovered through a percentage of the gross receipts
charge.
Rate Setting
A commercial service airport is designed to service two distinct
groups: the airlines and the commercial entities serving them, and the
passengers and those retail enterprises which service them [16]. The
airport leases its facilities to the airlines, concessionaires, industries,
general aviation, and airport support services. The airlines lease
ground for aircraft storage and space for ticket counters, operations,
maintenance, and baggage handling, and they pay fees for landing
and ramp rights. Cargo and hangar facilities are also utilized by the
airlines at specific locations. Concessionaires rent space within the
terminal and are charged on the basis of the amount and quality of
space rented and a percentage of receipts. Those franchisees outside
the terminal, such as taxicab companies, are charged in various ways.
One method is based upon the number of passengers enplaned at the
airport, and another is a fixed rate based upon the number of times
the airport is utilized for the service.
The method for determining rates varies from airport to airport.
For the last part of the twentieth century, the most common method
was the residual cost approach. In such an approach, the total annualized costs of the airport are reduced by the amount of all nonairline
revenues, and the remainder is proportioned among the airlines
based upon level of activity measures. Those costs apportioned to
Finance Strategies for Airport Planning
the terminal area are divided by the gross terminal area to determine
space rental charges. Those costs apportioned to the airfield are
divided by the total annual gross landing weight of the carriers at
the airport to determine landing fees. This type of cost recovery
approach essentially guarantees that the airlines will provide the
revenues necessary to cover airport costs. It also places the airlines in
a unique position relative to airport management in that the airlines
have a vested interest in maximizing nonairline revenues to minimize their costs.
Residual cost agreements were commonly longer term agreements, ranging from 20 to 50 or more years. As most of these agreements were signed between 1945 and 1985, many of these agreements
are due to expire.
Rather than extend or renew these traditional agreements, airports are exploring more dynamic and flexible rate setting policies.
Such approaches attempt to classify airport expenses into distinct
cost centers and to apportion the cost of each among users through
equitable rates, or to assign the expenses associated with certain cost
centers directly to users and to group other expenses to be shared by
all users. This type of rate setting is called the compensatory cost
method.
The test of the validity of any rate setting scheme, however,
lies in its ability to reflect rates which are reasonable and justifiable to the airlines, concessionaires, and other tenants. An illustration of the mechanics of rate setting and the determination of
measures to assess financial feasibility are contained in Example
Problem 13-1.
Example Problem 13-1 Estimate the rates and charges required to support the
capital costs of airport development shown in Table 13-2. Use the compensatory
cost method of determining rates and charges. The capital costs are financed by
issuing 6 percent bonds which are repaid in 20 years. Financial considerations
Airfield
$72,265,000
Apron area and concourses
$46,510,000
Main terminal building
$50,000,000
Parking facilities
$15,400,000
Airport access roads
Land acquisition
Total
TABLE 13-2
$4,260,000
$10,980,000
$199,415,000
Airport Capital Development Costs for
Example Problem 13-1
565
566
Special Topics in Airpor t Planning and Design
require a 1.25 coverage factor on revenues to support the repayment of airport
development bonds. The interest earned at an annual rate of 6 percent on the
accumulated balance in the capital recovery fund is to be used to decrease the
rates and charges.
The airport is being developed for an initial annual enplaned passenger
level of 2 million, and it is expected that the annual demand will increase to
4 million enplaned passengers in 20 years. Air carrier demand is expected to
increase from 48,000 to 96,000 annual operations and total aircraft operations
are expected to increase from 150,000 to 250,000 annual operations over the
20-year period. Assume that the increases in annual passengers and aircraft
operations are constant in each year rather than the growth rate of annual
passengers and operations being constant. The air carrier aircraft mix using
the airport is expected to consist of 25 percent Boeing 767-200 and 75 percent
McDonnell-Douglas MD-87 aircraft. A typical general aviation aircraft will
have a maximum certified landing weight of 3000 lb. The airport will be developed with four wide-bodied gates to accommodate the Boeing 767-200 and
12 narrow-bodied gates to accommodate the MD-87. The main terminal building will have an area of 250,000 ft2 exclusive of the concourses housing the
aircraft gates.
The Boeing 767-200 is found to have a maximum certified landing weight of
272,000 lb, a wingspan of 156 ft 1 in, and an average capacity of 236 passengers.
The MD-87 has a maximum certified landing weight of 130,000 lb, a wingspan
of 107 ft 10 in, and an average capacity of 135 passengers.
The rates and charges to the airport users must recover the capital development costs, including bond interest, over the capital recovery period of the
bonds, which is 20 years.
In general, airfield costs are recovered through landing fees, apron area
and concourse costs through ramp charges, terminal building costs through
square foot rental charges, and parking facility costs through parking rates.
The costs for the ground access system and the land acquisition are usually
allocated to the other charges to recover these costs. Sometimes the ground
access system costs are allocated to either the terminal building or parking
charges or to both. In this problem, the ground access system and land acquisition costs total $15,240,000 and represent about 8 percent of the total project
cost. Therefore, all rates and charges would be increased by 8 percent to cover
these costs.
First, the determination of landing fees is made. Generally, landing fees are
charged to only the commercial air carriers at an airport. Since the air carrier
demand will double over the 20-year span, the total number of air carrier aircraft
landings using the airport over a 20-year period will be about 720,000. Assuming
that the air carrier mix over the project period is constant, the average landing
weight of the air carrier aircraft is expected to be 0.25 × 272,000 + 0.75 × 130,000 =
165,500 lb. Therefore, the total landed weight of all air carrier aircraft over the
project life is found to be 720,000 × 165,500 = 119,160,000,000 lb.
If bonds are issued to finance the project, the bond interest payments for
20 years are equal to $72,265,000 × 0.06 × 20 = $86,718,000. The required average annual contribution to the capital recovery fund to repay the face value
of the bonds, considering the interest earned on the accumulated surplus, is
$2,414,500. Therefore, the air carrier landing fee must generate a total revenue
of $86,718,000 + 20 × $2,414,500 = $135,008,000.
To recover the airfield cost through air carrier landing fees, the average rate
per 1000 lb of landed weight is found to be $135,008,000 ÷ 119,160,000 = $1.13. The
landing fee that must be assessed to air carrier aircraft to recover the airfield costs
Finance Strategies for Airport Planning
is computed for the Boeing 767-200 as $1.13 × 272 = $307.36 and for the MD-87
as $1.13 × 130 = $146.90. (The reader should examine the cash flow for each year
to determine that the required revenue is attained through the fees calculated.
If this is done, it will be found that the landing fee must be increased to about
$1.15 per thousand pounds to realize sufficient revenue to pay the bond interest
and retire the bonds at the end of 20 years. In any situation in which rates are
based on a varying demand, a cash flow analysis should be performed to verify
the rates and charges, as average values of demand typically yield either too
little or too much revenue.)
It is instructive to look at the impact of a policy which charges general aviation aircraft landing fees on the cost to air carriers. Since there are initially 102,000
annual general aviation operations which increase to 154,000 annual operations
in the design year, general aviation aircraft over the project life will conduct
about 1,280,000 landings. General aviation aircraft at this airport average about
64 percent of the aircraft fleet. Therefore, the average landed weight of all aircraft
using the airport is equal to 0.64 × 3000 + 0.36 × 165,500 = 61,500 lb. The total
landed weight of all aircraft over the project life is then found to be 2,000,000 ×
61,500 = 123,000,000,000 lb.
To recover the airfield cost through landing fees assessed to all aircraft, the
average rate per 1000 lb of landed weight is found to be equal to $135,008,000 ÷
123,000,000 = $1.10. This is not a significant reduction from the case where only air
carrier aircraft were charged landing fees. The landing fee that must be assessed to
air carrier aircraft to recover the airfield costs is computed for the Boeing 767-200
as $1.10 × 272 = $299.20 and for the MD-87 as $1.10 × 130 = $143.00. For general
aviation aircraft the landing fee is $1.10 × 3 = $3.30.
Clearly there is very little benefit to air carrier aircraft from a policy which
charges landing fees to all aircraft using the airport. Furthermore, the design of
the airfield is significantly impacted by the presence of air carrier aircraft, and
these costs are appreciably higher than if the airfield were designed for only
general aviation aircraft. Collecting general aviation aircraft landing fees also
presents an operational problem for airport management, and the cost of collecting the fee will very likely exceed the fee collected. Airport management must
determine the best method of charging general aviation aircraft for airport use
if landing fees are not assessed to these users.
Next a determination of ramp fees for air carrier aircraft is made. Normally,
ramp fees are charged to the airlines to recover the cost of the apron and concourse system. The ramp fee is based upon the wingspan of the gate design
aircraft.
In this problem, the average wingspan of the gate design aircraft is computed
as 0.25 × 156.1 + 0.75 × 107.84 = 120 ft. The total wingspan of the aircraft occupying
the 16 gates is then 16 × 120 = 1920 ft. The cost of the apron and concourse development was $46,510,000. The interest payments on the bonds over 20 years will
be $55,812,000. The required average annual contribution to the capital recovery
fund to repay the face value of the bonds, considering the interest earned on the
accumulated surplus, is $1,551,000. Therefore, the air carrier landing fee must generate a total revenue of $55,812,000 + 20 × $1,551,000 = $86,832,000. Therefore, the
cost per foot of gate over the life of the project is $86,832,000 ÷ 1920 = $45,225. This
means that each of the Boeing 767-200 gates would cost $45,225 × 156.1 = $7,059,600
and that each of the MD-87 gates would cost $45,225 × 107.84 = $4,877,100. This
is a significant cost to the airline leasing the gate. Since there are 720,000 landings
over a 20-year period, there will be 45,000 aircraft occupancies at each gate. The
cost per aircraft for gate use is then $156.88 for a Boeing 767-200 and $108.38 for
an MD-87.
567
568
Special Topics in Airpor t Planning and Design
The cost of the main terminal building is usually recovered through squarefoot rental charges. However, typically only about 50 percent of the space
in a terminal building is rentable. Therefore, the space in the main terminal
building which is rentable is 0.50 × 250,000 = 125,000 ft2. The cost of the main
terminal building is then recovered based upon this area. The cost of the main
terminal building is $50 million. The interest payments on the bonds over
20 years will be $60 million. The required average annual contribution to the
capital recovery fund to repay the face value of the bonds, considering the
interest earned on the accumulated surplus, is $1,359,300. Therefore, the main
terminal building area charges must generate a total revenue of $60,000,000 +
20 × $1,359,300 = $87,186,000. Therefore, the cost per square foot to recover
terminal building costs is then $87,186,000 ÷ 125,000 = $698 over the life of
the project. Assuming a 20-year project life, this becomes $35 per square foot
per year.
Since typically about 40 percent of the terminal building area is rented
by the airlines this represents a total annual cost to the airlines of $35 × 0.40 ×
250,000 = $3.5 million. This represents a lifetime cost of $70 million to the
airlines which is significant since the airlines normally operate from many
airports.
Parking charges are used to recover the cost of the parking facility. This
requires that one know the number of parkers and average parking duration.
If it is assumed that vehicle occupancy rates are 2.5 passengers per vehicle,
then 4 million annual enplaned passengers translate to 1.6 million annual
vehicles with enplaning passengers in the design year. Since over time the
enplaning and deplaning passengers are about the same, this means a total
of 3.2 million vehicles on the ground access system during the design year.
Typically 70 percent are passenger cars, and of these typically 30 percent
park. The number of vehicles parking in the design year is then 0.70 × 0.30 ×
3,200,000 = 672,000.
The total number of vehicles parking in the parking facilities over the project
life is then about 10,080,000. The parking facility cost is $15,400,000. The interest
payments on the bonds over 20 years will be $18,480,000. The required average annual contribution to the capital recovery fund to repay the face value
of the bonds, considering the interest earned on the accumulated surplus, is
$517,400. Therefore, the terminal area charges must generate a total revenue of
$18,480,000 + 20 × $517,400 = $28,828,000. The average parking rate required
is $28,828,000 ÷ 10,080,000 = $2.86 per vehicle. This requires that time-related
parking rates be established based upon the average vehicle parking time to
realize a revenue of $2.86 per parked vehicle.
As noted earlier, one method of recovering land acquisition and ground
access system costs is to proportionally increase the other rates for the effect
of these costs. In this problem, all the above rates would be increased by
8 percent for this purpose, since these costs are about 8 percent of the total
project development costs. Additionally, bonding agencies usually require
that the airport demonstrate that its rate structure will realize actual revenues which are 1.25 times the required revenues to retire airport debt. This
is called bond coverage. Therefore, each of the rates and charges evaluated
above must be increased in this problem by 0.08 + 0.25 = 0.33, or 33 percent,
for these purposes.
Based upon the cost recovery and allocation factors discussed above, and to
account for the allocation of ground access system and land acquisition costs
as well as the impact of bond interest and coverage, the final rates and charges
can be determined. A Boeing 767-200 aircraft would be assessed a landing
Finance Strategies for Airport Planning
fee of $409 and a ramp fee of $209. An MD-87 aircraft would be assessed
a landing fee of $195 and a ramp fee of $144. Tenants would be charged a
rental fee of $47 per square foot per year. Parking charges would average
about $3.80. The total number of enplaned passengers serviced over this
20-year project life is 60,500,000. The total number of deplaned passengers
would also be about 60,500,000. Including the bond coverage requirements,
the average cost per passenger for landing fees and ramp charges amounts to
$4.92, and the total airport development cost per enplaned passenger is equal
to $449,346,000 ÷ 60,500,000 = $7.42. Each of these metrics is an indicator of
the financial viability of the development project. In both cases these are very
reasonable values.
It should be emphasized that airport rates and charges include
not only capital development costs but also the operating and maintenance costs associated with the airport. These charges are usually
reevaluated each year by the airport.
The compensatory cost method of determining rates and charges
was used in Example Problem 13-1. It is likely that very different rates
and charges would be realized if the residual cost method were used.
This is shown in Example Problem 13-2.
Example Problem 13-2 Estimate the landing fees required to support the capital
costs of the airfield development in Example Problem 13-1 if a passenger facility
charge is imposed at the rate of $2 per enplaned passenger for 10 years. This passenger facility charge is dedicated to airfield development. Solve this problem,
using the residual cost method of determining rates and charges and assuming
that the passenger facility charge is the only additional revenue received by
the airport (Table 13-2). As before, the airport is being developed for an initial
annual enplaned passenger level of 2 million, and it is expected that the annual
demand will increase to 3 million enplaned passengers in 10 years. Therefore,
the total revenue gained from the passenger facility charge is $2 × 25,000,000 =
$50,000,000. The net cost of airfield development, including interest over the
20-year period, becomes $117,802,100 − $50,000,000 = $67,802,100. The average
landing fee to support airfield development over a capital recovery period of
20 years will be determined.
Since the air carrier demand doubles over the 20-year span, the total number
of air carrier aircraft landings using the airport over a 20-year period will still
be about 720,000. The average landing weight of the air carrier aircraft is still
equal to 165,500 lb and the total landed weight of all air carrier aircraft over the
project life is still 119,160,000,000 lb.
To recover the net airfield development cost through air carrier landing fees,
the average rate per 1000 lb of landed weight is then found to equal $67,802,100
÷ 119,160,000 = $0.57. Therefore, the landing fee that must be assessed to air carrier aircraft to recover the airfield costs is computed for the Boeing 767-200 as
$0.57 × 272 = $155.04 and for the MD-87 as $0.57 × 130 = $74.10. As in Example
Problem 13-1, to account for land acquisition and ground access system costs,
and coverage, these landing fees must be increased by 33 percent. Therefore, a Boeing
767-200 aircraft would be assessed a landing fee of $206 and an MD-87 aircraft would
be assessed a landing fee of $99. The cash flow is shown in Table 13-3.
As may be observed, the residual cost method of determining rates and
charges results in a decrease in cost to the airlines.
569
570
Landing
Fee
Revenue $
Capital Recovery Fund
Year
Aircraft
Landing
Demand
Enplaned
Passenger
Demand
1
24000
2000000
2260068
4000000
6260068
4335900
1924168
1924168
2
25263
2111111
2379019
4222222
6601241
4335900
2265341
4304959
3
26526
2222222
2497970
4444444
6942415
4335900
2606515
7169772
4
27789
2333333
2616921
4666667
7283588
4335900
2947688
10547646
5
29053
2444444
2735873
4888889
7624761
4335900
3288861
14469366
6
30316
2555556
2854824
5111111
7965935
4335900
3630035
18967563
7
31579
2666667
2973775
5333333
8307108
4335900
3971208
24076825
8
32842
2777778
3092726
5555556
8648282
4335900
4312382
29833816
9
34105
2888889
3211677
5777778
8989455
4335900
4653555
36277400
10
35368
3000000
3330628
6000000
9330628
4335900
4994728
43448772
PFC
Revenue, $
Total
Revenue $
Bond
Interest $
Deposit $
Accumul $
11
36632
3100000
3449579
0
3449579
4335900
−886321
45169378
12
37895
3200000
3568531
0
3568531
4335900
−767369
47112172
13
39158
3300000
3687482
0
3687482
4335900
−648418
49290484
14
40421
3400000
3806433
0
3806433
4335900
−529467
51718445
15
41684
3500000
3925384
0
3925384
4335900
−410516
54411036
16
42947
3600000
4044335
0
4044335
4335900
−291565
57384134
17
44211
3700000
4163286
0
4163286
4335900
−172614
60654568
18
45474
3800000
4282237
0
4282237
4335900
−53663
64240180
19
46737
3900000
4401189
0
4401189
4335900
65289
68159879
20
48000
4000000
4520140
0
4520140
4335900
184240
72433711
720000
60500000
$67802100
$50000000
$117802078
$86718000
$31084078
$72433711
Total
TABLE 13-3 Landing Fee Cash Flow Analysis with Passenger Facility Charge for Example Problem 13-2
Finance Strategies for Airport Planning
Evaluation of the Financial Plan
Criteria for measuring the financial effectiveness of an airport plan
are usually determined by considering various evaluative measures
including these [21]:
1. The effectiveness of functional areas as measured by the ratios
of the amount of public space, revenue space, airline exclusive space, and concession space to the total space within the
terminal building
2. The relative effectiveness of areas within the terminal building, as indicated by the ratio of airline exclusive space to the
number of gates and the ratio of the ramp area to the total
building area
3. An evaluation of annual costs and revenues for various items
in each of the cost-center categories, as shown by the cost and
revenue per enplanement, per operation, per 1000 lb of aircraft landing weight, and per square foot of building space
4. The effectiveness of the schedule plan of the airline, as indicated by the number of departures per gate and enplaned
passengers per unit of airline exclusive space
The final determination of the most effective plan is made through
the process of discussion and negotiation between airport managers
and users. Various assumptions are made concerning the allocation of
costs and revenues between cost centers until a consensus is reached.
At this point airline lease agreements and concession policies are
developed which result in long-term commitments by the airlines and
tenants to the airport project. In the final analysis, airport expansion
plans must address not only the needs for changes in physical facilities but also the economic, environmental, and financial feasibility
associated with such development. It can be expected in this age of
limited financial resources, with energy and aircraft equipment needs
foremost in the management of airlines, that a clear determination of
the feasibility of airport expansion projects will be required before
long term commitments for support by the airline will be made.
References
1. AOCI Uniform Airport Financial Statement, Airport Operators Council
International, Inc., Washington, D.C.
2. Airport Administration and Management, John R. Wiley, Eno Foundation for
Transportation, Inc., Westport, Conn., 1986.
3. Airport Economics Manual, Doc. No. 9562, International Civil Aviation
Organization, Montreal, Canada, 1991.
4. Airport Finance, Norman Ashford and Clifton A. Moore, Van Nostrand Reinhold,
New York, N.Y., 1992.
571
572
Special Topics in Airpor t Planning and Design
5. Airport Planning and Management, D. F. Smith, J. D. Odegard, and W. Shea,
Wadsworth Publishing Company, Belmont, Calif., 1984.
6. Airport Economic Planning, Airport Revenues and Expenses, G. P. Howard,
Editor, MIT Press, Cambridge, Mass., 1974.
7. Economics of Airport Operation, Calendar Year 1972, J. A. Neiss, Federal Aviation
Administration, Washington, D.C., April 1974.
8. Eleventh Annual Report of Operations Under the Airport and Airway Development
Act, Fiscal Year Ended September 30, 1980, U.S. Department of Transportation,
Federal Aviation Administration, Washington, D.C., 1981.
9. Fort Lauderdale-Hollywood International Airport Economic Feasibility, Preliminary
Report, Aviation Planning Associates, Inc., Cincinnati, Ohio, April 1981.
10. General Aviation and the Airport and Airway System: An Analysis of Cost Allocation
and Recovery, National Business Aircraft Association, Inc., Washington, D.C.,
April 1981.
11. Hearings before the Subcommittee on Aviation of the Committee on Commerce, U.S.
Senate, Washington, D.C., July 1969.
12. National Airport System Plan, 1978–1987, Federal Aviation Administration,
Department of Transportation, Washington, D.C.
13. National Airspace System Plan, Federal Aviation Administration, Washington,
D.C., 1989.
14. National Plan of Integrated Airport Systems (NPIAS) 1990–1999, Federal Aviation
Administration, U.S. Department of Transportation, Washington, D.C., 1991.
15. Passenger Facility Charges, Part 158, Federal Aviation Regulations, Federal
Aviation Administration, Washington, D.C., June 1991.
16. Planning for Airport Access: An Analysis of the San Francisco Bay Area, Conference
Publication 2044, National Aeronautics and Space Administration, Ames
Research Center, Moffett Field, Calif., May 1978.
17. Reauthorizing Programs of the Federal Aviation Administration, Future Capacity
Needs and Proposals to Meet Those Needs, Subcommittee on Aviation, Committee
on Public Works and Transportation, House of Representative Report No. 101-37,
U.S. House of Representatives, Washington, D.C., 1990.
18. Senate Report No. 97–97, Airport and Airway System Act of 1981, Committee on
Commerce, Science, and Transportation, U.S. Senate, Washington, D.C., May 15,
1981.
19. State Funding of Airport and Aviation Programs, National Association of State
Aviation Officials, Washington, D.C., 1981.
20. Tenth Annual Report of Accomplishments Under the Airport Improvement Program,
Fiscal Year 1991, Federal Aviation Administration, Washington, D.C., 1992.
21. The Apron-Terminal Complex, The Ralph M. Parsons Company, Federal Aviation
Administration, Washington, D.C., September 1973.
22. The States and Air Transportation: Expenditures and Tax Revenues, Center for
Aviation Research and Education, National Association of State Aviation
Officials, Silver Spring, Md., 1991.
23. Airport Planning and Management, 5th ed., Alex Wells and Seth Young,
McGraw Hill Publishing, New York, N.Y., 2003.
24. Innovative Finance and Alternative Sources of Revenue for Airports, Cindy Nichol,
Transportation Research Board, ACRP Synthesis 1, Washington, D.C., 2007.
CHAPTER
14
Environmental
Planning
Introduction
The current concern for an assessment and understanding of the
environmental, ecological, and sociological consequences of development actions has resulted in the emergence of a holistic approach to
planning. This approach views all actions as being undertaking in a
single system and examines the consequences of these actions in
terms of the entire system. Traditionally, proposals for transportation
facilities have been evaluated in terms of sound engineering and
technological principles, economic criteria, and benefits to the users
and community. However, policy decisions today are being made
with a more complete awareness of the impacts of these decisions on
both users and nonusers from economic, social, environmental, and
ecological viewpoints.
Airports must be planned in a manner which ensures their
compatibility with the environs in which they exist. There are many
serious compatibility problems which presently exist in the vicinity
of airports which represent a serious confrontation between two
important characteristics of urban economics, the need for airports
to meet transportation needs and the continuing demand for community expansion. Airport planning must be conducted within
the context of a comprehensive regional plan. The location, size,
and configuration of an airport must be coordinated with the existing and planned patterns of development in a community, considering the effect of airport operations on people, ecological systems,
water resources, air quality, and the other areas of community
concern [9].
This chapter presents an overview of the factors which must be
considered to assess and evaluate the impact of airport development
decisions in the context of a system’s approach to planning.
573
574
Special Topics in Airpor t Planning and Design
Policy Considerations
In the United States, the overall basis for policies related to the consideration of the environmental, ecological, and social impacts of airport development is rooted in the National Environmental Policy Act
of 1969 (Public Law 91-190). The policy of the Department of Transportation (DOT) is
To integrate national environmental objectives into the missions and
programs of the department and to:
1. Avoid or minimize adverse environmental effects wherever possible;
2. Restore or enhance environmental quality to the fullest extent
practicable;
3. Preserve the natural beauty of the countryside and public park and
recreational lands, wildlife and waterfowl refuges, and historic sites;
4. Preserve, restore, and improve wetlands;
5. Improve the urban physical, social and economic environment;
6. Increase access to opportunities for disadvantaged persons; and
7. Utilize a systematic, interdisciplinary approach in planning and decision making which may have an impact on the environment. [43]
To implement this policy the FAA has established an environmental assessment and consultation process which provides the relevant
officials, policy makers, and the public with an understanding of the
potential environmental consequences of proposed actions and ensures
that the decision-making process includes environmental assessments
as well as economic, technological, and other factors relevant to the
decision. It requires that environmental impact statements and negative declarations serve to document and record compliance with this
policy and reflect a thorough study of all relevant environmental factors using a systematic, comprehensive, and interdisciplinary approach.
The National Environmental Policy Act (NEPA) requires
All agencies of the Federal government to include in every recommendation or report on proposals for legislation and other major Federal
actions affecting the quality of the human environment, a detailed statement on:
1. The environmental impact of the proposed action;
2. Any adverse environmental effects which cannot be avoided should
the proposal be implemented;
3. Alternatives to the proposed action;
4. The relationship between local short-term uses of man’s environment and the maintenance and enhancement of long-term productivity; and
5. Any irreversible and irretrievable commitments of resources which
would be involved in the proposed action should it be implemented.
Environmental Planning
Complementing this overall policy statement, the FAA also
established an Aviation Noise Abatement Policy (Public Law 96-193
and Public Law 101-508) to significantly reduce the adverse impacts
of aviation noise on existing land uses and to achieve a substantial
degree of noise compatibility between airports and their environs.
It has endorsed coordinated actions between aircraft operators and
owners, the FAA, the airport owners and sponsors, and the community. It proposed several actions to achieve airport noise control
and land-use compatibility including source noise reductions
through aircraft retrofit and replacement, modifications of landing
and takeoff procedures, and compatibility plans which have the
objective of containing severe noise impacts within airport controlled areas.
Noise is the most apparent impact of an airport upon the community but due consideration is required for all of those social,
economic, environmental, and ecological factors which are influenced by airport activity. These factors may be grouped into four
categories which can be identified as pollution factors, social factors, ecological factors, and engineering and economic factors [22].
The pollution factors include air and water quality, noise, and construction impacts. The social factors include land development,
the displacement and relocation of businesses and residences,
parks and recreational areas, historic places and archeological
resources which may be impacted, areas which are unique because
of natural or scenic beauty, and the consistency of the proposed
development with local planning. The ecological factors include
the impact on wildlife and waterfowl, flora and fauna, endangered
species, and wetlands or coastal zones. The engineering and economic factors include a consideration of flood hazards, costs of
construction and operation, benefits of implementation, and energy
and natural resource use.
The FAA has identified the requirements for environmental impact
assessment (EA) reports, environmental impact statements (EIS), and
findings of no significant impact (FONSI) for various types of projects,
and has also categorically excluded certain types of projects from the
requirements of a formal environmental assessment [2, 43]. Table 14-1
lists a breakdown of the type of environmental study required for
some common airport planning actions.
The general format for an environmental study consists of a
statement of need for the proposal, an inventory of problems and
issues, an identification of constraints and opportunities, an identification of the improvement components including physical and nonphysical entities, measures to increase benefits and reduce harm, a
discussion of the alternatives and their impacts, and the manner and
degree of community and public agency involvement in the process
[2, 36, 43].
575
576
Special Topics in Airpor t Planning and Design
Typical actions normally requiring environmental assessment:
Airport location
New runway
Major runway extension
Runway strengthening to permit use by noisier aircraft
Major expansion of terminal or parking facilities
Establishment or relocation of instrument landing system
Land acquisition
Required for facility modifications
Relocation of business or residences
Affecting historical, recreational, or archaeological resources
Affecting wetlands, coastal zones, or floodplains
Affecting endangered or threatened species
Typical actions normally requiring environmental impact statement:
Adoption of a new airport system plan if criteria are
substantially different from former plan
First-time airport location or airport layout planned
New runways capable of serving air carrier traffic in metropolitan areas
∗
See Federal Aviation Administration [43].
Source: Federal Aviation Administration [2].
TABLE 14-1 Environmental Study Requirements of Airport Development
Project
*
Pollution Factors
Air Quality
Many of the larger, more densely populated urban areas are facing
serious difficulties associated with the emission of dangerous gaseous and particulate matter into the atmosphere due to industrial
processes, combustion, and transportation. Air pollution affects the
public welfare including the personal comfort and health of man,
causes damage to soil, water, vegetation, wildlife, animals, deterioration of property and the erosion of property values, and a reduction
in visibility resulting in losses of aesthetic appeal and increased hazards in transportation. Air pollution is defined as the introduction of
foreign substances or compounds into the air or the alteration of the
concentrations of naturally occurring elements. Hub airports with a
considerable volume of commercial jet aircraft traffic may contribute
substantially to this problem.
Air quality is defined by the concentration level of six pollutants
for which standards have been adopted, namely, carbon monoxide,
Environmental Planning
hydrocarbons, nitrogen oxides, sulfur dioxide, suspended particulates, and photochemical oxidants. The standards are specified in the
Clean Air Act and consist of two categories, primary standards related
to health and secondary standards related to welfare.
The amount of a particular pollutant produced by an aircraft is a
function of the type of engines and the mode of operation of the aircraft [17]. An analysis must include a consideration of aircraft idling
at the gate and runway threshold, engine power run-ups, taxiing,
takeoff, climb-out, approach, and landing. The dispersion of the pollutants is studied through the use of either emission models or diffusion models. The emission model assumes a uniform dispersion of
the pollutants within the atmosphere of concern, whereas the diffusion model uses emissions or emission rates together with physical
and meteorological conditions to determine concentrations of pollutants. A study of the air quality impacts for an airport project requires
a determination of ambient air quality, local meteorological conditions, the mix, number, and paths of aircraft using the airport, and
the emission rate of the aircraft in different operating modes. It also
requires a knowledge of the operating characteristics and volume of
ground transportation modes providing access to and services at the
airport, and the point sources of pollution occasioned by the normal
operation of an airport. A flow chart of the interaction of those factors
which are normally considered in an air quality study at an airport is
given in Fig. 14-1. The results of an air quality study are typically
displayed on maps which show the before and after concentration of
pollutants in the area of the airport, together with charts indicating
the level of compliance with air quality standards.
Water Quality
Water is one of the most valuable resources on earth. Not only is it essential for the maintenance of life itself but it is also used by man in nearly
all daily activities. As the population has grown, so has the demand for
water, and today, that need is so great that in many areas of the world the
need has outpaced the supply. The construction and operation of airport
facilities can contribute to the degradation of the quality and reduction
of the quantity of groundwaters or surface waters. Water quality can be
affected by the addition of soluble or insoluble organic or inorganic
materials into rivers, streams, and aquifers resulting in a water source
which is inadequate to support aquatic life and other uses such as fishing, swimming, and water supply needs. Changes in the cover, composition, and topography of the ground in the vicinity of airport sites can
cause changes in the amount, peaking, routing, and filtration of runoff
and the recharge area of aquifers. Construction-related activities may
cause the introduction of materials and wastes into streams and water
sources, increases in the volumes of sanitary wastes and water supply
demand, and increases in storm water management systems.
577
578
Special Topics in Airpor t Planning and Design
AIRPORT CONFIGURATION
Flight Paths
Runways
Taxiways
Aprons
Fuel Farms
Maintenance
Access Roads
Service Roads
TRAVEL DEMAND
Aircraft
Access Vehicles
Service Vehicles
Number
Type
Mix
NETWORK OPERATIONS
Flow Rates
Speeds
VEHICLE
CHARACTERISTICS
EMISSIONS
METEOROLOGICAL
CONDITIONS
DIFFUSION
CHEMICAL REACTIONS
AMBIENT
CONDITIONS
AIR
QUALITY
IMPACTS
PLANT LIFE
ANIMAL LIFE
HEALTH
FIGURE 14-1 Flow chart illustrating air quality study process for airports.
A water quality study for an airport facility should address both
the direct and indirect effects of the project on water quality [8, 21].
The direct effects include soil erosion, the amount and composition of
runoff from the facility, infiltration, spills, turbidity, and the quantities of water supply and sewage disposal needs. Indirect effects
include the accelerated weathering of exposed geologic and construction materials, disruption of nutrient cycles for the support of life,
and the extraction of construction materials which may alter natural
filtering, the degree of imperviousness of soils, and water storage
capacity. Typically, a water quality study will identify the source and
receptors of pollutants, and the amount of degradation which the
introduction of pollutants will cause. It will also address the impact
on the quantity of water sources through a determination of flow
rates, flow and recharge areas, permeability, infiltration, and flow
interruptions. Construction measures utilized to minimize degradation of water quality and supply include the construction of check
dams, sediment traps, berms, dikes, channels, and slope drains, sodding
Environmental Planning
and seeding, brush barriers, and paving. Wastewater management
plans are usually prepared integral with a review of this impact area
[8, 21, 30].
Aircraft and Airport Noise
The effects that noise from aircraft have on communities surrounding
airports present a serious problem to aviation. Since commercial jet
transport operations began in 1958, the public reaction to aircraft
noise has been vigorous. Because of these reactions much has been
learned about the generation and propagation of noise and about
human reactions to noise. On the basis of this knowledge, procedures
have been developed which permit the planner to estimate the magnitude and extent of noise from airport operations and to predict
community response. Several of these procedures are outlined here.
The impact of aircraft noise on a community is dependent upon several factors including the magnitude of the sound, the duration of the
sound, the flight paths used during takeoff and landing, the number
and types of operations, the operating procedures, the aircraft mix,
the runway system utilization, the time of day and season, and meteorological conditions. The response of communities to exposure to
aircraft noise is a function of the land and building use, the type of
building construction, the distance from the airport, the ambient noise
level, and community attitudes [9, 45].
Quantifying Aircraft Noise
Like most other environmental issues, aircraft noise has many dimensions. Most of these dimensions relate to the reaction of people to
aircraft noise. These reactions relate to the sound level, the varying
sensitivity of the human ear to different frequencies or pitches of sound,
the frequency of occurrence of aircraft noise intrusions, the time of day
these intrusions occur, and the number of intrusions that occur over a
period of time such as a day. Given this range of dimensions, it is not
surprising that several metrics of aircraft noise have been developed
over the years. While some were built into the first sound meters over
a half century ago, most have been developed since the introduction of
the first transport category turbojet aircraft in the late 1950s.
Many metrics have been developed over the years to describe aircraft noise. Some of the more common ones are presented in the following paragraphs. The goal of these metrics is to quantify aircraft
noise in a manner which relates the physical aspects of sound to
human assessments of loudness and noisiness. These metrics are
the basis of most noise analyses conducted at airports throughout
the United States and elsewhere. In addition, there are other similar
noise metrics with specialized purposes and these are also discussed.
These are effective perceive noise level (EPNL), composite noise rating
(CNR), and noise exposure forecast (NEF).
579
580
Special Topics in Airpor t Planning and Design
Sound Pressure and Sound Pressure Level
All sounds come from a sound source such as a musical instrument,
a voice speaking, or an airplane passing overhead. Sound energy
radiated by such sources is transmitted through the air in sound
waves which are tiny pressure fluctuations just above and below
atmospheric pressure. These pressure fluctuations, called sound pressures, impinge on the ear, creating audible sound. Sound pressures
are quantified by the root-mean-square (RMS) value, that is, the
square root of the average squared pressure fluctuation over some
brief period of time (about 1 s for aircraft noise purposes) as shown in
Eq. (14-1).
⎛1
prms = ⎜
⎝T
⎞
∫t = 0 p(t)2 dt⎟⎠
T
1/2
(14-1)
where prms = root mean square sound pressure
p(t) = deviation from atmospheric pressure at time t
T = averaging time, 1 s for airport noise purposes
The human auditory system is sensitive to a very wide range of
RMS sound pressures. The loudest sounds people can hear without
pain have about 1 million times the RMS sound pressure as the faintest sounds people can hear. Equally remarkable is the way the auditory system perceives changes in loudness. To a first approximation,
equal percentage changes in RMS sound pressure are perceived as
equal changes in loudness. Hence, at higher RMS sound pressures,
larger absolute changes in RMS sound pressure are required to make
a noticeable difference in loudness than at lower RMS sound pressures. The smallest difference in RMS sound pressure the human
auditory system can detect is about 10 percent.
For these reasons a logarithmic, or decibel scale, is well suited for
quantifying sound in a manner which relates to human perception. In
its logarithmic form, RMS sound pressure is called the RMS sound
pressure level (SPL). Sound pressure level is the logarithm of the ratio
of two squared pressures, the numerator containing the pressure of
the sound source of interest and the denominator containing a reference pressure, as shown in Eq. (14-2). The units of sound pressure
level are decibels (dB).
⎛ p2 ⎞
L p = 10 log ⎜ rms
2 ⎟
⎝ p0 ⎠
(14-2)
where Lp = RMS sound pressure level
prms = RMS sound pressure
p0 = reference pressure of 20 × 10−6 newtons per square
meter or 2.90 × 10−9 pounds per square inch
log = logarithm to the base 10
Environmental Planning
The value of p0 has been chosen to approximate the lowest RMS sound
pressure a healthy young adult can hear. Substituting this barely
audible RMS sound pressure for prms in Eq. (14-2) produces a sound
pressure level of 0 dB. In contrast, an RMS sound pressure 1 million
times greater produces a sound pressure level of 120 dB. Most sounds
in our day-to-day environment have sound pressure levels on the
order of 30 to 100 dB. Two useful rules of thumb for comparing sound
pressure levels are that, on an average, people perceive a 6 to 10 dB
increase in the sound pressure level as a doubling of subjective loudness and changes of less than 2 or 3 dB are not readily detectable
outside of a laboratory environment.
The A-Weighted Sound Level
Another important attribute of sound is its frequency, or pitch. For a
pure tone this is the number of times per second the sound pressure
oscillates back and forth about atmospheric pressure. The unit of frequency is hertz (Hz) but may also be referred to as cycles per second
in references predating the adoption of hertz as an international
standard. Virtually all sounds contain energy across a broad range of
frequencies. Even a single note of a musical instrument contains a
fundamental frequency plus a number of overtones.
The normal frequency range of hearing for a young adult extends
from a low of 16 Hz to a high of about 16,000 Hz. However, the human
auditory system is not equally sensitive across this entire range. Frequencies in the range of 2000 to 4000 Hz sound louder than lower or
higher frequencies when heard at the same RMS sound pressure
level. Thus, it is possible for two different sounds with the same
sound pressure level to sound different in loudness.
For this reason the A-weighted sound level (A-level) was developed.
Incorporated in almost every commercially available sound level
meter, a standardized A-weighting filter adds gain or attenuation to
different frequencies in a manner approximating the sensitivity of the
human ear. The frequency response of the filter has a ±3 dB effect in the
midfrequency range between 500 and 10,000 Hz and increasing attenuation outside this range. Although the A-weighting filter is only an
approximation to a complex physiological process, one sound judged
louder than another will generally have a higher A-weighted sound
level. Similarly, two sounds judged equally loud will generally have
nearly the same A-weighted sound levels. A range of commonly
encountered A-weighted sound levels is shown in Fig. 14-2.
For environmental assessment purposes, the A-weighted sound
level represents a significant improvement over the overall
(unweighted) sound pressure level. Unweighted sound pressure
levels are rarely, if ever, used in environmental analyses. All federal
agencies dealing with community noise, including transportation,
have adopted the A-weighted sound level as the basic unit for analysis
of environmental impacts.
581
582
Special Topics in Airpor t Planning and Design
A-Weighted
Sound Level (dB)
CONCORDE, LANDING 1000 m. FROM RUNWAY END
110
747-100 TAKEOFF 6500 m. FROM START OF TAKEOFF ROLL
100
727-200 6500 m. FROM START OF TAKEOFF
DIESEL TRUCK AT 50 ft.
90
NOISY URBAN DAYTIME
80
GARBAGE DISPOSAL AT 3 ft.
SHOUTING AT 3 ft.
757-200 6500 m. FROM START OF TAKEOFF
70
VACUUM CLEANER AT 10 ft.
COMMERCIAL AREA
CESSNA 172 LANDING 1000 m. FROM RUNWAY END
60
Rock Band
INSIDE SUBWAY TRAIN (New York)
FOOD BLENDER AT 3 ft.
NORMAL SPEECH AT 3 ft.
LARGE BUSINESS OFFICE
QUIET URBAN DAYTIME
50
DISHWASHER NEXT ROOM
QUIET URBAN NIGHTTIME
40
SMALL THEATRE, LARGE CONFERENCE
(Background)
QUIET SUBURBAN NIGHTTIME
LIBRARY
30
BEDROOM AT NIGHT
CONCERT HALL (Background)
QUIET RURAL NIGHTTIME
20
BROADCAST & RECORDING STUDIO
10
THRESHOLD OF HEARING
0
FIGURE 14-2 Common environmental A-weighted sound levels in decibels (Harris
Miller Miller Hanson).
A-weighted sound levels are measured in decibels as are
unweighted sound pressure levels and several other metrics discussed in this chapter. Thus, the measurement units themselves do
not identify the quantity being reported. To avoid ambiguity the
quantity, in this case the A-weighted sound level, should always be
reported along with the units. An example would be an A-weighted
sound level of 85 dB. [Although not meeting current acoustical terminology standards, A-weighted sound levels may be reported in
the literature as dBA, dB(A), or simply A-weighted.]
Maximum A-Weighted Sound Level
In addition to sound level, another important dimension to environmental sound is its variation over time. For example, a distant
highway with relatively steady traffic produces a fairly continuous
background sound level with moment-to-moment variations of only
Environmental Planning
90
80
70
60
50
40
30
0
50
100
150
200
Time, seconds
250
300
350
FIGURE 14-3 Typical A-weighted sound level time history of an aircraft pass-by
(Harris Miller Miller Hanson).
a few decibels. In contrast, an aircraft pass-by produces a distinct,
transient noise event. During an aircraft pass-by, the sound level
emerges out of the fluctuating background environment, continues
to increase until the aircraft passes the observer, and then decreases
to blend in with the background as the aircraft recedes into the distance. Figure 14-3 illustrates this phenomenon.
For reporting as well as comparison purposes it is desirable to use
a single number for describing the sound level of such a noise event.
A convenient metric is the maximum A-weighted sound level. This
value is convenient to measure as it requires an observer to simply note
the maximum reading on a sound level meter. It is also convenient to
describe since most people can relate to the loudest part of a noise
event. In Fig. 14-3 the maximum A-weighted sound level is 85 dBA.
Sound Exposure Level
While being a very useful metric of aircraft noise events, the maximum level does not address the time element, or duration, of the
event. During the late 1960s and early 1970s several psychoacoustic
listening studies were conducted to investigate how people assessed
the relative noisiness of noise events with differing durations. All
other things being equal, it was found that increased duration resulted
in greater perceived noisiness. On average, the studies determined
that people were willing to trade a doubling of duration for a 3-dB
reduction in maximum A-level sound. This finding supported a
simple model for subjective noisiness, noise events with equal timeintegrated A-weighted sound energy are rated as equally noisy.
583
584
Special Topics in Airpor t Planning and Design
Developed to address this finding, the sound exposure level (SEL) is
defined as the total A-weighted sound energy contained in the noise
event. Its description as a continuous integral is shown in Eq. (14-3).
The units are decibels. Theoretically, this integral could approach
infinity as T becomes large. If the integration takes place over the top
20 dB, the computation will be only 0.1 dB less than the theoretical
maximum.
⎛1
L AE = 10 log ⎜
⎝ T0
T
∫t = 0 10 L
At /10
⎞
dt⎟
⎠
(14-3)
where LAE = sound exposure level
T 0 = 1 s to maintain a dimensionless argument for the
logarithm
LAt = continuous A-weighted sound level function describing
the noise event time history. The limits of t from 0 to T
are sufficient to encompass the top 10 to 20 dB of the
noise event.
For measurement purposes, the continuous integral presents two
difficulties, namely, a continuous, mathematical function for the
A-weighted sound level time history is never known, and the time
limits of integration are nebulous since there is no precisely defined
beginning or end to an aircraft noise event which slowly emerges
from, and then blends back, into a time-varying background. These
difficulties are circumvented using discrete samples of A-weighted
sound level, the summation approximation of Eq. (14-4) and empirically derived guidelines for the limits of i from 1 to N.
⎛1
L AE = 10 log ⎜
⎝ T0
N
∑ 10 L
i=1
A ,i /10
⎞
Δt⎟
⎠
(14-4)
where LA,i is the instantaneous, ith A-weighted sound level measured
every 0.5 s and Δt is 0.5 s. The limits of i from 1 to N are sufficient to
perform the summation over at least the top 10 dB of the noise
event.
An accepted sampling interval Δt is 0.5 s. If the summation
starts, i equal to 1, with the first sample to come within 20 dB of
the maximum value and continues until the last sample, i equal to
N, is within 20 dB of the maximum, this approximation will be
about 0.1 dB lower than the theoretical value. If the summation is
performed only over the top 10 dB of the time history, the discrepancy will be less than 1 dB. This discrete summation approximation
to the integral is used in all sound level meters and monitoring
devices. The use of Eq. (14-4) in computing SEL is illustrated in
Example Problem 14-1.
Environmental Planning
Example Problem 14-1 The following sample of A-weighted sound levels was
measured at 0.5-s intervals during an aircraft flyover: 64.5, 66.7, 67.1, 69.2, 71.3,
73.2, 74.1, 75.6, 77.8, 79.1, 78.6, 77.2, 75.7, 74.5, 72.6, 71.1, 69.7, 68.6, 68.0, and
66.4 dB.
To determine the SEL of this noise event, we must substitute into Eq. (14-4)
obtaining
⎡1
⎤
L AE = 10 log ⎢ (1064 . 5/10 + 1066 . 7/10 + ⋅ ⋅ ⋅ + 1066 . 4/11 0 )0 . 5]⎥
⎣1
⎦
= 10 log(253, 734, 091) = 84 . 0 dB
It will be observed that even though none of the individual sound events had
an A-weighted sound level in excess of 79.1 dB the effect of the duration of the
noise event leads to a numerically higher value for the SEL.
Because of the sound level durations involved with typical aircraft
pass-bys, the SEL will always be numerically larger than the maximum A-weighted sound level of the event. For most aircraft overflights, the difference is on the order of 7 to 12 dB. Factors affecting this
difference are aircraft speed (the greater the speed, the smaller the difference) and the distance to the aircraft at its closest point of approach
to the observer (the greater the distance, the greater the difference).
Equivalent Steady Sound Level
The preceding discussion focused on measures of sound associated
with individual events. However, it is frequently necessary to quantify sound levels over longer periods of time, such as an hour, several
hours, or even a day. Such needs arise when tracking diurnal patterns, describing cumulative exposure over intermediate exposure
periods (such as during school or office hours), or cumulative exposure over a 24-h day. In contrast to the energy summation metrics used
for individual noise events, energy average metrics are used for longer
time periods. One such metric is the equivalent steady sound level (QL).
Although not meeting current acoustical terminology standards, the
equivalent steady sound level reported in the literature as energy
average sound level, Leq or LEQ and the units are decibels. Mathematically, the equivalent steady sound level is the sound pressure level
shown in Eq. (14-2) calculated using a long-term RMS sound pressure
(T in Eq. (14-1) equals to the time period of interest). As a practical
matter, the equivalent steady sound level is almost always calculated
from a time series of A-weighted sound levels acquired with a sound
level meter with readings taken at 0.5 s intervals or less. Equation
(14-5) shows the manner in which the equivalent steady sound level
is computed from a discrete time series of data.
⎛1 N
⎞
Leq = 10 log ⎜ ∑ 10 L A ,i /10 Δt⎟
⎝ T i=1
⎠
(14-5)
585
586
Special Topics in Airpor t Planning and Design
where Leq = equivalent steady sound level
LA,I = instantaneous ith A-weighted sound level measured
every 0.5 s
T = time period of interest (e.g., 1 h)
Δt = typically 0.5 s or less
N = T/Δt, where T and Δt must be in the same units
An equivalent and computationally more efficient manner of expressing Eq. (14-5) is
⎛1
Leq = 10 log ⎜
⎝N
N
∑ 10 L
i=0
⎞
⎟
⎠
A ,i /10
(14-6)
where LA,i is the instantaneous ith A-weighted sound level measured
every 0.5 s and N is total number of sound level samples.
The computational process described in Eqs. (14-5) and (14-6)
does not make any distinction between sources, that is, it accumulates sound levels produced by both aircraft and nonaircraft sources.
When QL is computed in this manner it is called total QL. However, it
is often useful to know only the aircraft component. The aircraft component can be calculated from the sound exposure levels of individual
events using Eq. (14-7).
⎛ 1 M L /10⎞
Leq = 10 log ⎜ ∑ 10 AE , j ⎟
⎠
⎝ T j=1
(14-7)
where LAE,j = sound exposure level produced by the jth aircraft passby during the time period
T = time period of interest (e.g., 1 h) measured in seconds
M = number of aircraft noise events during the period T
Functionally, this equation accumulates all of the aircraft sound energy
from multiple events, then spreads it out uniformly over the time
period by dividing by the length of the period (not just the length of
time that aircraft were present).
The computation of hourly average sound level is illustrated in
Example Problem 14-2.
Example Problem 14-2 The following sound exposure levels for four aircraft
flyovers were measured in a 1-h period: 84.0, 89.1, 90.2, and 86.6 dB.
To compute the hourly average sound level, we must substitute into
Eq. (14-7) obtaining
⎡ 1
⎤
(1084 . 0/10 + 1089 . 1/10 + 1090 . 2/1 0 + 1086 . 6/10 )⎥
Leq = 10 log ⎢
⎣ 3600
⎦
= 10 log 713 . 339 ≈ 58 . 5 dB
Environmental Planning
It will be observed that even though the sound exposure level of each aircraft
flyover was greater than 58.5 dB the averaging process reduces the hourly average sound exposure level.
Experience has shown the concept of an average sound level is
often misinterpreted by the affected public as an underreporting or
understatement of their noise environment. Their concern is that the
metric does not report the total noise energy over the time period. As
can be seen in Eqs. (14-5), (14-6), and (14-7), this metric, as well as
other average metrics, does indeed include all of the noise energy.
Each and every noise event, no matter how high or low the sound
level, increases the value of the metric. Viewed another way, the average value is the total noise energy adjusted by a constant, 10 log T.
The local community component of the equivalent steady sound
level is also a frequently reported statistic which serves as a basis of
comparison for the aircraft component. It may be estimated using a
variant of Eq. (14-6) which accumulates sound levels only during subintervals of the total period when no aircraft are present. It is an estimate because there is no way of knowing the community sound level
contribution during periods when aircraft are present. Equation (14-8)
shows the basic summation process. Each summation in the equation
represents a nonaircraft subinterval.
Nn
N2
⎡ 1 ⎛ N1
⎞⎤
Leq = 10 log ⎢ ⎜∑ 10 L A ,i /10 + ∑ 10 L A ,i /10 + ⋅ ⋅ ⋅ + ∑ 10 L A ,i /10⎟ ⎥ (14-8)
⎢⎣ N ⎝ i = 1
i=1
i=1
⎠ ⎥⎦
where
LA,i = instantaneous ith A-weighted sound level measured every 0.5 s
N1, N2, Nn = number of sound level samples in each subinterval
containing no aircraft noise
N = total number of samples which is equal to (N1 +
N2 + · · · + Nn)
This metric is referred to as the hourly average sound level when
1 h of averaging time is used. (Although not meeting current acoustical
terminology standards, the hourly average sound level may be reported
in the literature as the hourly noise level, HNL, hourly Leq or 1-h Leq.) In
airport applications, hourly average sound levels may be used for plotting and visualizing diurnal trends. Eight and twenty-four hour periods
are referred to as 8-h and 24-h average sound levels. The symbol Leq is
generic referring to any arbitrary period of time. To avoid ambiguity,
the subscript is replaced by the appropriate time frame. Thus, the symbols L1 h, L8 h, and L24 h, are used for 1-, 8-, and 24-h periods, respectively.
Day-Night Average Sound Level
As the name implies, the day-night average sound level, DNL, is a
metric used to describe sound exposure over a 24-h period and the units
587
588
Special Topics in Airpor t Planning and Design
are decibels. Computationally it is identical to the 24-h average sound
level with one important difference. The DNL incorporates a time-ofday weighting which adds 10 dB to sound levels occurring between 10
p.m. and 7 a.m. While the magnitude of the weighting periodically
becomes a topic of discussion within the scientific community, the
intent is to account for a presumed increase in human sensitivity to
noise during nighttime hours. While the formal definition is a continuous integral, Eq. (14-9) shows the formula for computing the total
(aircraft plus community sources) DNL from discrete samples of the
A-weighted sound level.
N
⎛ 1
⎞
10( L A ,i + Wi )/10 Δt⎟
Ldn = 10 log ⎜
∑
86
400
,
⎝
⎠
i=1
where
(14-9)
Ldn = day-night average sound level for 1 day
LA,i = instantaneous ith A-weighted sound level measured
every 0.5 s
86,400 = number of seconds in a day
Wi = time-of-day weighting for the ith A-weighted sound
level (0 dB if it occurred between 7 a.m. and 10 p.m.,
10 dB if it occurred between 10 p.m. and 7 a.m.)
Δt = typically 0.5 s or less and the units must be in seconds
N = equal to 86,400/Δt
The aircraft component of DNL may be computed from sound
exposure levels of individual events using Eq. (14-10).
M
⎛ 1
⎞
W )/
(L
10 AE , j + j 10⎟
Ldn = 10 log ⎜
∑
,
86
400
⎠
⎝
j=1
(14-10)
where LAE,j = sound exposure level produced by the jth aircraft passby during the day
Wj = time-of-day weighting for the jth aircraft pass-by (0 dB
if it occurred between 7 a.m. and 10 p.m., 10 dB if it
occurred between 10 p.m. and 7 a.m.)
M = number of aircraft noise events during 24-h period
The application of this equation to determine the DNL of several
aircraft flyovers at various times during the day is illustrated by
Example Problem 14-3.
Example Problem 14-3 The following sound exposure levels of five aircraft
flyovers were measured over the course of a 24-h period: 81.2 dB at 6:03 a.m.,
95.1 dB at 10:32 a.m., 79.2 dB at 2:15 p.m., 88.8 dB at 7:33 p.m., and 71.2 dB at
10:05 p.m.
Environmental Planning
To compute the DNL, we must substitute into Eq. (14-10). The sound exposure
levels at 6:03 a.m. and 10:05 p.m. must be increased by the time of day weighting
of 10 dB since these flyovers occurred between 10:00 p.m. and 7:00 a.m.
⎡ 1
⎤
Ldn = 10 log ⎢
(1091 . 2/10 + 1095 . 1/10 + ⋅ ⋅ ⋅ + 108 1 . 2/10 )⎥
⎣ 86, 400
⎦
= 10 log 63,978.85 = 48.1 dB
To find the aircraft which has the greatest and least contribution to the daynight average sound level the (LAE,j + Wj)/10 value of the quantity 10 must be
evaluated for each aircraft. Clearly, by adding the time of day weighting, we see
that the aircraft flyover at 10:32 a.m. is the greatest contributor and the aircraft
flyover at 2:15 is least contributor to the day-night average sound exposure
level.
A useful rule of thumb for estimating the contribution of DNL to
a single daytime (7 a.m. to 10 p.m.) noise event may be obtained by
simplifying Eq. (14-10) for the condition, where M is equal to 1. The
approximation shown in Eq. (14-11) is accurate to within 0.5 dB.
Ldn ≈ LAE − 50
(14-11)
where LAE is the sound exposure level of a single aircraft pass-by.
The use of Eqs. (14-10) and (14-11) to compute the DNL of a single
daytime noise event is illustrated by Example Problem 14-4.
Example Problem 14-4 Let us determine the DNL produced by a single daytime
noise event with a sound exposure level of 105 dB.
Using Eq. (14-10), we have
⎡ 1
⎤
Ldn = 10 log ⎢
(10105 . 0/10 )⎥
⎣ 86, 400
⎦
= 10 log 366,004 = 55.6 dB
Using Eq. (14-11), we have
Ldn ≈ 105 − 50 ≈ 55 dB
If this noise event were added to the noise events in Example Problem 14-3,
we would find that the DNL was increased to 56.3 dB or there would be an
increase of 0.7 dB.
Environmental reporting criteria often require annual average
values of DNL. Both airport and atmospheric factors contribute to
day-to-day variability in the DNL observed at a particular location
near the airport. In cases where average values must be computed
from measurements, the averaging must be done on a sound energy
589
590
Special Topics in Airpor t Planning and Design
basis. Equation (14-12) shows the formula for computing the annual
average value.
⎛ 1 365 L /10⎞
Ldn , annual = 10 log ⎜
∑ 10 dn ,i ⎟⎠
⎝ 365 i = 1
(14-12)
where Ldn,i is the DNL for the ith day of the year.
This equation assumes 365 individual DNL values are to be used
in the averaging process. For conditions where the number of days
differs from 365 (leap years, missing data, etc.) the available number
of data points should be used in the summation and the number 365
replaced by the actual number of data points used.
Representative values of DNL range from a low of 40 to 45 dB in
extremely quiet isolated locations to highs of 80 or 85 dB immediately
adjacent to a busy truck route or just off the end of a runway at an
active military air base. The U.S. Environmental Protection Agency
(EPA) identified this measure as the most appropriate means of evaluating community (including aircraft) noise in 1974 [28]. Most other
public agencies dealing with noise exposure, including the FAA, the
Department of Defense, and the Department of Housing and Urban
Development (HUD), have also adopted DNL in their guidelines and
regulations.
Time Above Threshold Level
The preceding metrics quantify noise exposure in terms of sound
level or sound energy. An alternate descriptor uses duration, or time,
as the basic metric. The metric is time above (TA), defined as the length
of time that the A-weighted sound level exceeds a specified threshold
level over a given period of time. Typically TA is reported as the numbers of minutes per day that the A-weighted sound level exceeds values of 55, 65, 75, 85, 95, and 105 dB. The historical appeal of TA has
generally been one of simplicity, that is, TAs are arithmetically additive. TAs for single noise events can be arithmetically added to compute hourly TAs, and hourly TAs can be arithmetically added to form
24-h values. Proponents of TA argue that the arithmetic addition
process allows easy-to-understand assessments of major contributors
to 24-h totals. TA may be required for some environmental analyses.
However, at the present time there are no accepted criteria or landuse compatibility guidelines using TA.
Other Single-Event Sound-Level Metrics
The perceived noise level (PNL) and effective perceived noise level (EPNL)
are quantities similar to A level and sound exposure level, respectively. They were developed specifically to correlate with subjective
response to aircraft sound. The perceived noise level, in units of
PNdB, is a quantity which varies from moment to moment, just like
the A-weighted sound level. As a general rule, the perceived noise
Environmental Planning
level is approximately 13 dB greater than the A-weighted sound
level.
The effective perceived noise level, in units of EPNdb, is a single
event metric which sums the perceived noise level in a manner similar to the way SEL sums A-level. EPNL, however, also incorporates a
tone correction adjustment to account for the increased subjective
noisiness of sounds containing discrete frequency tones (like those
produced by turbofan engine compressor blades). The formula for
computing EPNL is shown in Eq. (14-13) [39].
⎛1
LEPN = 10 log ⎜
⎝ T0
N
∑ 10( L
PN ,i
i=1
+ TCi )/10
⎞
Δt⎟
⎠
(14-13)
where LEPN = effective perceived noise level
LPN,i = instantaneous ith perceived noise level measured every
0.5 s
TCi = instantaneous ith tone correction
Δt = 0.5 s
T0 = 10 s. The limits of i from 1 to N are sufficient to perform
the summation over the top 10 dB of the noise event.
Both the PNL and the tone correction are computed from sound
pressure levels measured in individual one-third octave bands from
50 to 10,000 Hz. The magnitude of the tone correction ranges from 0
to 6 dB depending upon the frequency where the tone occurs and the
sound pressure level of the tone relative to the broadband noise in the
same frequency range. As a general rule, the EPNL is about 3 dB
greater than SEL but can be more if very noticeable pure tones are
present, or less at very large distances.
Because of the complexity involved in measurement, sophisticated frequency analyses and nonlinear amplitude adjustments are
required, they are not used in the United States for routine environmental analyses. Their current use is limited to aircraft airworthiness
certification under Federal Aviation Regulations, Part 36 [39].
Other 24-h Sound-Level Metrics
The community noise equivalent level (CNEL) adopted in California airport
noise standards was actually a forerunner of DNL. The computation
procedure is virtually identical to DNL. Equations (14-9) and (14-10) can
be used to compute CNEL, the only difference is the use of 3 weighting
periods instead of 2. For 7 a.m. to 7 p.m. the weighting is 0 dB, for 7 p.m.
to 10 p.m. the weighting is 4.77 dB (the actual weighting is a factor of 3 in
sound energy and 10 log 3 or 4.77 dB), and for 10 p.m. to 7 a.m. the
weighting is 10 dB. The only difference between the two metrics is the
approximately 5 dB weighting during the three evening hours from
7 p.m. to 10 p.m. Numerically, CNEL is always greater than DNL but
from a practical standpoint this difference is rarely more than 1 dB.
591
592
Special Topics in Airpor t Planning and Design
Before the adoption of DNL, two other descriptors of daily noise
exposure were used to quantify noise impacts around airports. Neither is still in active use in the United States today. The composite noise
rating (CNR) was one of the first 24-h metrics to embody individual
aircraft sound levels, their frequency of occurrence, and their time-ofday in a single number rating. Predating the development and use of
personal computers by more than two decades, CNR calculations
were performed using a handbook procedure published in 1963
under a joint effort by the U.S. Air Force and the FAA. CNR used the
maximum perceived noise level as the single event sound level
descriptor.
The noise exposure forecast (NEF) was developed in 1967 and
quickly replaced CNR. The NEF uses EPNL as the single event sound
level descriptor and a sound energy summation process similar to
DNL. Equation (14-14) shows the formula for computing NEF.
Because of the computational complexities involved in their underlying single event metrics, both CNR and NEF fell into disuse with the
adoption of DNL.
⎛M
⎞
L
W )/10
NEF = 10 log ⎜∑ 10( EPN,j + j ⎟ − 88
⎠
⎝ j=1
(14-14)
where LEPN,j = EPNL produced by the jth aircraft pass-by during the
day
Wj = time-of-day weighting for the jth aircraft pass-by (0 dB
if it occurred between 7 a.m. and 10 p.m., 12 dB if it
occurred between 10 p.m. and 7 a.m.)
88 = adjustment factor designed to shift the metric to a
lower numeric range not occupied by any other thencurrent 24-h metric
Because of differences in frequency weightings, differences in
accounting for the durations of individual events, and differences in
the evening and nighttime weightings, there is no exact functional
relationship between these three metrics. Within ±3 dB, however, the
relationship shown in Eq. (14-15) has been found to be valid. Thus,
for DNL and CNEL values of 65, an NEF value of 30, and a CNR
value of 100, all indicate approximately the same degree of noise
exposure, within ±3 dB.
Ldn ≈ NEF + 35 ≈ CNR − 35
(14-15)
Aircraft Noise Effects and Land-Use Compatibility
The effects of noise on people can be classified into one of two
categories, namely, behavioral effects and health or physiological
effects. Behavioral effects are those that are associated with activity
Environmental Planning
interference. These effects include annoyance, interference with communication, mental activity, rest, and sleep. Health effects are those
that produce hearing loss or nonauditory effects such as cardiovascular disease and hypertension.
Various federal agencies have developed guidelines for assessing
the compatibility of noise with land uses, including the EPA, HUD, and
the FAA. All of the guidelines are based on the day-night average sound
level (DNL) and were designed to protect public health and welfare, but
also take into account the feasibility of controlling noise [28, 44].
Speech Interference
One of the primary effects of aircraft noise is its tendency to drown out
or mask speech, making it difficult or impossible to carry on a normal
conversation without interruption. The sound level of speech decreases
as distance between a talker and listener increases. As the level of
speech decreases in the presence of background noise, it becomes
harder and harder to hear. Figure 14-4 presents typical distances
between a talker and listener for satisfactory outdoor conversations in
the presence of different steady A-weighted background sound levels
for three degrees of vocal effort, namely, raised, normal, and relaxed.
As the background level increases, the individuals must either talk
louder or must get closer together to continue their conversation.
Steady A-Weighted Sound Pressure in Decibels
90
Rai
80
sed
Nor
70
Voic
e
ma
l Vo
ice
Rel
axe
60
Rel
isfa
ctor
Sat
isfa
ctor
yC
onv
ersa
onv
ers
atio
onv
ers
atio
dC
onv
ers
n (S
atio
40
tion
yC
dC
axe
50
Sat
ent
n (S
ntel
enc
telli
e In
ce I
ent
e In
enc
nten
n (S
enc
ent
(Se
ligib
gibi
e In
lity
ility
telli
gibi
lity
95%
)
95%
)
99%
telli
)
gibi
lity
30
100
%)
20
0.3
0.4
0.6 0.8 1
1.5
2
3
4
6
8 10
15
20
Communicating Distance in Meters
FIGURE 14-4 Maximum distances outdoors over which conversation is satisfactorily
intelligible outdoors in a steady noise environment (Adapted from Environmental
Protection Agency [28] ).
593
594
Special Topics in Airpor t Planning and Design
As indicated in the figure, satisfactory conversation does not always
require hearing every word, 95 percent intelligibility is acceptable for
many conversations. This is because a few unheard words can be
inferred when they occur in a familiar context. However, for relaxed
conversation, people have higher expectations of hearing speech and
require complete 100 percent intelligibility. Any combination of talkerlistener distances and background noise that falls below the bottom
line in Fig. 14-4, thus ensuring 100 percent intelligibility, represents an
ideal environment for outdoor speech communication and is considered necessary for acceptable indoor conversation as well.
One implication of the relationships in Fig. 14-4 is that for typical
communication distances of 3 or 4 ft (1 to 1.5 m), acceptable outdoor
conversations where 95 percent intelligibility is acceptable can be carried on in a normal voice as long as the background A-weighted
sound level is less than about 65 dB. In other situations, where greater
speech intelligibility is required, background levels must be lower.
For example, indoors, where 100 percent intelligibility is desired, the
background A-weighted sound level must be less than about 45 dB. If
the noise exceeds either of these levels, as might occur when an aircraft passes overhead, intelligibility is lost unless vocal effort is
increased or communication distance decreased.
A second implication of these relationships is that an acceptable
A-weighted background level of 60 to 65 dB outdoors does not guarantee an acceptable background level indoors. This is because most
housing construction typically provides about 15 dB of sound attenuation from outside to inside the building when windows are open.
Thus, only if the outdoor A-weighted sound level is 60 dB or less is
there a reasonable chance that the resulting indoor sound level will
afford acceptable conversation inside.
Sleep Interference
The disruptive effects of noise on sleep can be of concern in communities
exposed to aircraft overflights during nighttime hours. Over the past
two decades, many investigations of noise-induced sleep disruption
have been conducted worldwide. The functional relationship most often
evaluated has been the probability of a sleep disruption created by a
single noise intrusion of a given sound level. Four major research review
studies [10, 32, 37, 46] all support the same general finding that increased
sound exposure level (SEL) results in higher probabilities of sleep disruption. Currently, however, there are no guidelines or acceptability
criteria for assessing the cumulative impact of many aircraft noise intrusions of various SELs over the course of a nighttime sleeping period.
The aforementioned reviews provide some insight as to why such
guidelines and criteria have not been forthcoming. Data acquisition
methodologies, the treatment of mitigating variables, and the choice
of both dose and disruption metrics are far from standardized, even
for studies limited to short-term, transient noise events similar to
those produced by aircraft overflights.
Environmental Planning
Despite all of this variability, first order dose-response curves have
been developed which attempt to relate the probability of an arousal,
either a sleep stage change or an actual awakening, to the sound exposure level of a single noise event [11, 26]. At the present time caution
should be exercised in drawing inferences from such curves. Among
other things, the preponderance of underlying data generally represents
laboratory listening conditions. Thus the curves could be expected to
better predict reaction to new and unfamiliar sounds rather than older,
more familiar ones. When compared with in-laboratory studies, the
limited data available from in-home investigations using familiar sound
sources suggests that arousal probabilities may be on the order of only
one-eighth those observed from unfamiliar sources. In addition to these
adaptation issues, uncertainty still remains on important questions such
as the cumulative effects of multiple noise intrusions, the effects of noise
on falling asleep as opposed to awakening, and the extent to which
sleep deprivation represents a quantifiable physiological problem.
Community Annoyance
Social survey data have long made it clear that individual reactions to
noise vary widely for a given 24-h average sound level. As a group,
however, the aggregate response of people to factors such as speech
and sleep interference and desire for an acceptable environment is
predictable and relates well to measures of cumulative noise exposure such as DNL. Figure 14-5 shows the most widely recognized
Percentage of People Highly Annoyed
100
80
Range for 90%
of Survey Points
60
40
20
0
40
50
60
70
80
90
Day-Night Average Sound Level (decibels)
FIGURE 14-5 Percentage of people highly annoyed as a function of day-night
average sound level (Adapted from Schultz, Journal of the Acoustical Society
of America [49] ).
595
596
Special Topics in Airpor t Planning and Design
relationship between day-night average sound level and the percentage of people highly annoyed, regardless of the noise source. Based on
data from 18 studies of the attitudes of people toward noise conducted
worldwide, the curve indicates that the relationship between group
reaction and 24-h exposure is quantifiable. The curve shows that at
DNLs as low as 55 dB, approximately 5 percent of the people will still
be highly annoyed with their noise environment. The percentage
increases more rapidly as the DNL increases above 65 dB [49].
Separate work by the EPA suggests that overall community reaction to a noise environment is also dependent on the level of the
intruding noise as compared with the level of the existing noise.
Research was conducted to determine the relationship between
intruding noise level and community reaction for 55 cases of community noise intrusion where reactions were known [16]. The data
were normalized to the same set of conditions so that the cases were
comparable. In particular, the conditions were adjusted to an existing
noise environment, without the intruding noise, of about 60 dB. The
data show that sporadic complaints occurred when the intruding
equivalent noise level was between about 59 to 65 dB, and widespread complaints occurred when the intruding noise fell between
about 63 and 75 dB.
The implication of this research is that complaints may begin to
occur when aircraft DNL is approximately equal to the background
DNL, and that widespread complaints start to occur when the aircraft
DNL exceeds the background DNL by 3 to 5 dB. Such a conclusion
provides some assistance in anticipating what community reaction
could be to a change in the noise level of an intruding source, such as
an airport. If the change is likely to result in an increase above existing noise levels of 3 to 5 dB, some community reaction may be
expected [16].
Noise-Induced Hearing Loss
Hearing loss is measured as threshold shift. Threshold refers to the quietest sound a person can hear. When a threshold shift occurs, the
sound must be louder before it can be heard. For hundreds of years it
has been known that excessive exposure to loud noises can lead to
noise-induced temporary threshold shifts, which in time can result in
permanent hearing impairment. With a threshold shift of 25 dB a
person could correctly understand only about 90 percent of the
sentences spoken in a conversational level at a 3 ft (1 m) distance in
a quiet room [42].
Research over the last 40 years on industrial and military populations provides an understanding of the development of noise-induced
hearing loss and its relationship to noise level, spectral content and
length of exposure. Detailed international criteria have been developed
that identify maximum noise exposures that do not produce noiseinduced hearing loss in any segment of the population exposed [1].
Environmental Planning
The U.S. Occupational Safety and Health Administration (OSHA) regulation [41] identifies the maximum permissible A-weighted sound
exposure of 90 dB for 8 h.
It is extremely unlikely that aircraft noise around airports could
ever produce hearing loss. For example, it would take continuous
exposure to more than 1000 overflights per day with an SEL of 100 dB
each to produce a time-weighted average sound level of 85 dB. If this
occurred 5 days a week for 40 years, and if people were exposed to
this outdoors without any attenuation from buildings, the resultant
noise exposure would start to produce a noise-induced permanent
threshold shift (NIPTS) of less than 10 dB in the most sensitive 10
percent of the population.
Nonauditory Health Effects
Concern is often raised that noise has adverse effects on human health
other than hearing. In spite of considerable worldwide research,
however, no unambiguous scientific evidence to relate quantitatively
any noise environment with the origin of or contribution to any clinical nonauditory disease. Even the most recent research, conducted at
levels above the limits for conservation of hearing, failed to give consistent results. Most authoritative reviews, such as the World Health
Organization Environmental Health Criteria Document on noise [33],
agree that “research on this subject has not yielded any positive evidence, so far, that disease is caused or aggravated by noise exposure,
insufficient to cause hearing impairment.” For practical noise control
considerations, the present status of our knowledge means that by
using criteria that prevent noise induced hearing loss, minimize
speech and sleep disruption, and minimize community reactions and
annoyance, any effects on health will also be prevented. In general,
these guidelines should not be regarded as identifying levels of exposure that are desirable but rather as a balancing of what is desirable
with what is feasible.
Noise and Land-Use Compatibility Guidelines
Based on the relationships between noise and the collective response
of people to their environment, DNL has become accepted as a standard for evaluating community noise exposure and as an aid in decisionmaking regarding the compatibility of alternative land uses.
In their application to airport noise in particular, DNL projections
have two principal functions:
1. To provide a means for comparing existing noise conditions
with those that might result from the implementation of noise
abatement procedures or from forecast changes in airport
activity
2. To provide a quantitative basis for identifying and judging
potential noise impacts
597
598
Special Topics in Airpor t Planning and Design
Both of these functions require the application of objective criteria.
Government agencies dealing with environmental noise have devoted
significant attention to this issue and have developed noise and landuse compatibility guidelines to help federal, state, and local officials
with the noise evaluation process.
In FAR Part 150 [6], which defines procedures for developing airport noise compatibility programs, the FAA has established DNL as
the official cumulative noise exposure metric for use in airport noise
analyses, and has developed guidelines for noise and land-use compatibility evaluation. Table 14-2 presents these guidelines.
The guidelines represent a compilation of extensive scientific
research into noise-related activity interference and attitudinal response.
However, reviewers of DNL contours should recognize the highly
subjective nature of response to noise and the special circumstances
that can either increase or decrease the tolerance of an individual. For
example, a high nonaircraft background or ambient noise level, such
as from ground traffic, can reduce the significance of aircraft noise.
Alternatively, residents of areas with unusually low background levels
may find relatively low levels of aircraft noise very annoying. Response
may also be affected by expectation and experience. People often get
used to a level of noise exposure that guidelines suggest may be unacceptable, and similarly, changes in exposure may generate a response
that is far greater than that which the guidelines might suggest.
Finally, the cumulative nature of DNL means that the same level
of noise exposure can be achieved in an essentially infinite number of
ways. For example, a large increase in relatively quiet flights can
counter balance a smaller reduction of relatively noisy operations,
with no net change in DNL. The increased frequency of operations
can annoy residents, despite the apparent unchanged status quo of
the noise. With these cautions in mind, the guidelines of the FAA for
compatible land use can be combined with DNL contours indicating
points of equal exposure to identify the potential types and locations
of land uses and the degree of their incompatibility. Note that, by
these guidelines, all land uses are considered compatible with aircraft
day-night average sound levels below 65 dB. This does not mean that
people will not complain or otherwise be disturbed by aircraft noise
at lower levels, as has been shown earlier, nor does it preclude individual communities or other jurisdictions from adopting lower standards to meet local needs.
Determining the Extent of the Problem
The extent of a potential or ongoing airport noise problem is generally quantified in one of two ways:
1. Prediction using computer-based simulation models
2. Measurement through portable or permanent monitoring
systems
Environmental Planning
Yearly Day-Night Average Sound Level, DNL, dB
Below
Over
65
65–70 70–75 75–80 80–85 85
Residential Use
Residential other than Y
mobile homes and
transient lodgings
Mobile home park
Transient lodgings
Public Use
Schools
Hospitals and
Y
nursing homes
Y
Churches,
auditoriums, and
concert halls
Y
Governmental
services
Transportation
Parking
Commercial Use
Offices, business
Y
and professional
Y
Wholesale and
retail—building
materials, hardware,
and farm equipment
Retail trade—general Y
Utilities
Communication
Manufacturing and Production
Manufacturing general Y
Photographic and
Y
optical
Agriculture (except
Y
livestock) and
forestry
Livestock farming
Y
and breeding
Mining and fishing,
resource production
and extraction
N
N
N
N
N
Y
Y
N
N
N
N
N
N
N
N
N
N
Y
25
N
30
N
N
N
N
N
N
N
25
30
N
N
N
Y
25
30
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
25
30
N
N
Y
Y
Y
Y
N
Y
Y
Y
25
Y
Y
30
Y
25
N
Y
30
N
Y
N
Y
Y
Y
25
Y
30
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
N
N
N
Y
Y
Y
Y
Y
TABLE 14-2 FAA Noise and Land-Use Compatibility Guidelines
Y
N
N
N
Y
599
600
Special Topics in Airpor t Planning and Design
Yearly Day-Night Average Sound Level, DNL, dB
Below
Over
65
65–70 70–75 75–80 80–85 85
Recreational
Outdoor sports
arenas and
spectator sports
Outdoor
music shells,
amphitheaters
Nature exhibits and
zoos
Amusements, parks,
resorts and camps
Golf courses, riding
stables and water
recreation
Y
Y
Y
N
N
Y
N
N
N
N
N
Y
Y
N
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
25
30
N
N
N
Notes:
Y(Yes) Land use and related structures compatible without restrictions
N(No) Land use and related structures are not compatible and should be
prohibited
25, 30, or 35 Land use and related structures generally compatible; measures to
achieve outdoor-to-indoor Noise Level Reduction of 25, 30, or 35 dB
must be incorporated into design and construction of structure.
There are special provisions pertaining to many of the compatibility designations that are
not included here; refer to FAR Part 150 [6] for details.
Source: Federal Aviation Administration [36]
TABLE 14-2 FAA Noise and Land-Use Compatibility Guidelines (Continued)
The simulation models produce maps depicting contours of equal
sound level such as DNL. Measurements are used to provide or confirm input to the simulation models as well as to confirm model predictions at specific ground locations.
The Integrated Noise Model (INM) and NOISEMAP
Two computer-based simulation models are currently used in the
United States. Both produce maps showing contours of equal daynight average sound level. Developed by the FAA, the integrated
noise model (INM) is most often used for civil airports [29]. NOISEMAP,
developed by the U.S. Air Force, is generally used for military airbases
but is also used for civil and joint-use airports. The FAA has approved
both models for use in airport noise studies. The two models require
the same basic input parameters but formats differ.
Environmental Planning
Use of either model requires inputs in two principal categories,
namely, aircraft noise and performance data, and aircraft operational
data. The major difference between the two categories of input is that
the first is generally not airport dependent while the second is airport
specific and must be individually developed for each airport.
Aircraft Noise and Performance Data
The INM uses a standard, internal noise and performance data base
containing a large number of aircraft types. The model uses the noise
data to determine the SEL of specific aircraft types as a function of
thrust and distance from the observer. The performance data used by
the model define the length of the takeoff roll, climb rate, speed, and
thrust management for both departures and arrivals.
Aircraft Operational Data
The INM also requires operational input data specific to the airport under
study. These data are often difficult to obtain as they are not routinely collected by either the airport or the FAA. To address this problem, airports
are beginning to develop specific data collection procedures for this specific purpose. Operational inputs describe activity at the airport using
average values during the period of interest and include the following:
1. Physical description of the airport runways, including any
displaced takeoff or landing thresholds
2. Runway utilization percentages
3. Number of aircraft operations by aircraft type for all noisesignificant aircraft types in the fleet mix
4. Day-night split of operations by aircraft type
5. Flight corridor descriptions
6. Flight corridor utilization percentages
Noise Model Output
Both the INM and NOISEMAP produce output in two forms, namely,
contour maps of equal day-night average sound level, and detailed
tabular analyses for user specified ground locations. Figure 14-6 shows
an example of a DNL contour map. A typical map shows contours
from 60 to 80 dB at 5-dB intervals. For presentation purposes, these
contours are superimposed graphically on a good quality base map or
aerial photograph.
In addition to DNL contours, SEL contours can also be helpful in
addressing issues of sleep and speech interference and for analyzing
the effects of noise abatement procedures, such as proposed noise
abatement flight tracks. Graphical comparisons of SEL contours of
various aircraft types can also provide powerful images for comparing noise emissions of differing aircraft types.
601
602
Special Topics in Airpor t Planning and Design
FIGURE 14-6 Sound exposure level contour map for Greater Pittsburgh International
Airport (Aviation Planning Associates, Inc. [7] ).
Tabular listings for user-specified ground locations show not only
the predicted DNL but also the SEL and DNL contribution of individual aircraft by runway and flight corridor. This information is
invaluable for understanding the major contributors to the total DNL.
It can also be used to compare the model predictions with data from
noise monitoring locations. Such comparisons often provide the basis
for fine-tuning model inputs as well as promoting public confidence
in the computer model and the contours it produces.
Aircraft Noise and Operations Monitoring
Many civil aviation airports in the United States have installed aircraft
noise monitoring systems to assist in managing airport-community
relations. The first systems, installed 20 or more years ago, performed
strictly sound level monitoring. Current technology systems have
evolved into complete noise monitoring systems capable of providing information on both aircraft sound levels and aircraft operations.
The primary uses of airport noise and operations monitor systems are
to help establish and monitor compliance with noise abatement procedures, verify trends in overall fleet noise, and provide input and
validation data for computer-based airport noise simulation models.
When people complain about aircraft noise the complaint is often
followed by a reference to some operational characteristic of the aircraft which differed from their expectations, For example, “they’re not
Environmental Planning
supposed to fly directly over my house,” “that aircraft flew too low,” or
“they never used to use that runway so often.” While admittedly anecdotal in nature, such informative complaints can be extremely helpful
in pinpointing the operational source of the complaint and in starting a
process of noise mitigation and community education.
The operations side of the monitoring system provides airport
managers with the tools to verify the underlying cause of complaints,
determine the extent of identified problems, and provide an objective
basis for seeking solutions. The primary source of information for
modern systems is data routinely collected by the FAA with their
Automated Terminal Radar System (ARTS). The ARTS retains information sufficient to reconstruct the three-dimensional flight trajectory,
aircraft type, airline, flight number and type of operation (departure
or arrival) for every commercial aircraft movement. Modern, computerbased operations monitoring systems access these data, provide extensive on-line data storage capacity, and embody sophisticated data base
management systems for retrieving, sorting, and reporting the enormous volumes of data they acquire.
Useful, long-term summary statistics from operations monitoring
systems include the percentage runway utilization, with breakdowns
by departures and arrivals and by aircraft type, and overall traffic
counts, with breakdowns by aircraft type and by time-of-day. Detailed
presentations of actual aircraft flight tracks, such as those shown
in Fig. 14-7, are extremely helpful for examining noise abatement
O’HARE ARRIVALS
O’HARE DEPARTURES
MIDWAY ARRIVALS
MIDWAY DEPARTURES
FIGURE 14-7 Radar derived air carrier departure flight tracks in Chicago area
terminal airspace (Landrum and Brown Aviation Consultants [14] ).
603
604
Special Topics in Airpor t Planning and Design
alternatives. The data from operations monitoring systems are also
one of the few objective data sources for preparing accurate and
defensible airport noise contours.
The sound level monitoring side of the system consists of a
number of remote microphones located in the community surrounding the airport and a central processing site usually located at airport
administrative offices. Microphones are located on top of 7-m-high
poles and the microphone signal processed in real time at the pole to
compute and store most all of the sound level metrics of interest. Data
are then transmitted digitally from the microphone site to the central
station using a modem and voice-grade telephone lines.
Finding Solutions
Table 14-3 presents a matrix of aircraft-related noise problems and
potential solutions. In general, solutions to mitigate noise impacts
seek to increase distance between the aircraft and noise-sensitive
elements of the community, reduce noise levels at the source, or
reduce the numbers of noise events in noise-sensitive areas. Some
specific solutions require FAA expertise and approval and hence,
the involvement of the agency should be sought at the earliest possible opportunity. Details of some solutions are discussed in the following paragraphs.
Noise Barriers
Noise barriers offer opportunities for controlling ground-based noise
sources such as takeoff and landing roll, taxiway and apron movements, aircraft power-backs, auxiliary power units (APUs), and maintenance engine runs. To be effective, the barrier must break the line of
sight between the noise source and the receiver. Hence, they provide
no benefit once the aircraft is airborne and is visible above the barrier.
Maximum effectiveness is achieved when a barrier is close to either
the source or the receiver, rather than halfway between them.
Typical barriers are walls, earth berms or wall-berm combinations. Long buildings, such as the terminal itself, also make effective
barriers. Blocking the line of sight to APUs and low engine aircraft
such as the Boeing 737 usually requires barriers of only modest height,
assuming flat terrain. Blocking the line of sight to high tail-mounted
engines, such as those on the DC-10 or L-1011, presents a greater challenge. Barriers just blocking the line of sight generally provide about
5 dB of noise reduction. Higher barriers provide more.
For maintenance runups, a barrier is often in the form of a pen or
series of walls. A pen surrounds the aircraft as closely as possible but
allows entry through the front. It also contains a blast shield to prevent
engine exhaust damage to the barrier. Complete enclosures, often referred
to as hush houses, feature doors, roofs and exhaust silencing treatment.
They are used where large amounts of noise reduction are required.
∗These are examples of restrictions that involve the FAA’s responsibility for safe implementation. They should not be set in place unilaterally by the airport operator.
Source: Federal Aviation Administration [36].
TABLE 14-3
Matrix of Noise Control Actions
605
606
Special Topics in Airpor t Planning and Design
Along the runway sideline, especially in the vicinity of start-oftakeoff roll, barriers are most effectively placed near the residences
they are meant to protect. Obstruction height clearance requirements
usually preclude placing barriers close enough to the runway to be
effective in these locations.
Barrier performance can be degraded by temperature inversions
and winds with a component blowing in the direction of source to
receiver. This is especially true if the barrier cannot be located as close
as desired to the source or receiver. Under these atmospheric conditions, refracted sound travels a higher curved path from the source to
receiver, and sound attenuation is reduced or eliminated under extreme
conditions such as in high wind.
Sound Insulation
Sound insulation of structures, such as residences, seeks to improve
the environment indoors through treatment of the structure itself.
FAA funding criteria for sound insulation projects seek a 5-dB transmission loss improvement and a day-night average sound level
(DNL) goal of 45 dB indoors. Windows are usually the weak link in
the sound attenuation properties of structures. With windows open
the noise reduction properties of other parts of the structure are
largely irrelevant and a noise reduction up to 14 dB is all that can be
expected. With windows closed noise reduction is greater, but the
additional reduction is dependent on the extent of
1. Any remaining air gaps such as around windows and doors,
and through attic and basement vents
2. The thickness and number of panes of glazing
3. The weight of exterior doors
4. The weight of roofing and walls
Cost-effective sound insulation programs can achieve 25 to 35 dB
of noise reduction through attention to air gaps (caulking around
door and window frames, insulation of walls and attics, sound
absorbing material around attic vents and soffits), window treatment
(replacement of jalousie or poorly fitting windows, and use of double
strength or double pane glass in the form of special acoustical windows or storm windows), and doors (replacement of hollow core
with solid core units). In order to be effective during the summer
months, central air conditioning must also be part of a basic noise
insulation package so proper ventilation can be achieved with windows closed.
Enhancing roof and wall weight can provide additional benefit
once the aforementioned items are no longer the weak link. However,
the cost of ensuring that other elements are not the weak link, such as
installing triple instead of double glazing and sophisticated air duct
Environmental Planning
treatment, added to the cost of the structural enhancements themselves generally increases the cost significantly.
Preferential Runway System
The preferential runway concept is based on optimizing runway utilization under wind, weather, demand, and airport layout constraints to
minimize population impacts by taking advantage of uneven population
distribution around the airport. Preference is given, weather permitting,
to those runways for which arrivals or departures affect the fewest people. Considerable effort can be devoted to determining which runway
flight track combinations create the least noise impact and to developing
with the FAA a workable plan that can be implemented. Monitoring the
effectiveness of any preferential runway use program is important and
can also require significant effort to develop and implement.
Noise Abatement Departure Procedures and Flight Tracks
The FAA has developed a recommended noise abatement takeoff
procedure involving power settings and profile characteristics for
turbojet-powered aircraft with maximum certificated gross takeoff
weights in excess of 75,000 lb [34]. Most domestic airlines have incorporated this procedure or an equivalent in their flight manuals. The
National Business Aircraft Association (NBAA) has also developed
and recommended noise abatement procedures for turbojet business
aircraft. The objectives of the NBAA program are to ensure that jet
aircraft noise abatement procedures are safe, standardized and uncomplicated while at the same time being effective at reducing noise levels
in the community. Noise abatement departure procedures can also
include use of specific headings and turns to avoid populated areas.
The INM may be used to assess the effectiveness of such procedures.
Noise abatement flight paths can offer significant opportunities
for noise abatement where distribution of incompatible land uses is
uneven. Typically, noise abatement flight paths are designed to avoid
the noise sensitive areas and route air traffic over less sensitive areas.
Implementation of these kinds of flight paths will also require extensive interaction with the FAA. Again, the INM may be useful in
assessing the noise impacts of various flight tracks.
Airport Use Restrictions
Noise-based airport use restrictions address noise control through
reductions in the average noisiness of the aircraft that use the airport.
Use restrictions have come under court challenge, especially by the
FAA, as unduly restrictive of interstate commerce. In general, the
courts have found restriction of an airport to be legal if they are
1. Reasonable in the circumstances of the particular airport
2. Carefully tailored to the local needs and to community
expectations
607
608
Special Topics in Airpor t Planning and Design
3. Based upon data which support the need and rationale for
the restriction
4. Not unduly restrictive of interstate commerce
Several types of restrictions may be considered, particularly if they
are considered “voluntary.” Curfews or other nighttime use restrictions
are designed to reduce or eliminate noisy operations during late-night
hours when people may be particularly sensitive to noise. Such restrictions can have large DNL benefits relative to the number of aircraft
operations affected because of the 10-dB penalty added to noise between
10:00 p.m. and 7:00 a.m. when computing DNL. Aircraft operators may
react by canceling operations by restricted aircraft types, switching to
quieter aircraft types, or rescheduling.
Full curfews, such as eliminating all nighttime flights, have been
found to be overbroad and to impose undue burden on interstate commerce, and are often viewed as arbitrary and capricious. The overbroad
issue has to do with the fact that a full curfew may deny access to the
airport by users who, in fact, could operate quietly at night without
significant disruption to sleep. A full curfew might have interstate
commerce implications because of nighttime activity to and from outof-state destinations. The arbitrary and capricious test has to do with
whether or not a use restriction can be justified in terms of its noise
benefits. Perhaps the most important point to be made is that a
detailed quantitative noise analysis should be developed to provide
justification for any noise-based use restriction.
Use restrictions can also be based on FAA noise certification categories. These categories are identified in FAR Part 36 and discussed
later. These restrictions limit the use of the airport based on the
noise certification stage of the aircraft. For example, an airport may
adopt a restriction that limits the use of the airport to stage 3 aircraft
at night.
As part of the certification process specific noise levels are measured
for each aircraft [38] and use restrictions can be based on these specific
levels. For example, an airport could prohibit nighttime departures by
aircraft with certified noise levels exceeding 108 EPNdb.
Use restrictions do not have to be based on certified noise levels.
Certified noise levels may not be available for some older transport
category aircraft or for many general aviation aircraft. Certified noise
levels may also be deemed unrepresentative of the sound levels produced under actual local operating conditions. In such cases, it may
be preferable to set limits based on other published data [25] or on the
noise levels measured at the airport itself.
Noise-based landing fees provide an economic incentive to discourage the operation of noisier aircraft, especially during noisesensitive times of the day. Noise-based landing fees are proportional
in some way to the noise produced by the aircraft. For example, an
Environmental Planning
operator may be charged more for a takeoff by a stage 2 aircraft than
for the same operation by a stage 3 aircraft. Alternatively, the fee may
be higher for a night departure than for a day departure by the same
aircraft. To be effective, however, the fee structure must be set high
enough to affect airport user decision making.
Noise Regulations
Federal aviation noise regulations are identified in a number of forms.
The highest form of regulations are those set forth in various parts of
Title 14 of the Code of Federal Regulations (14 CFR). This section of
the federal code is called the Federal Aviation Regulations (FAR). The
FAA also publishes orders and advisory circulars. Orders are procedures to which FAA staff must adhere in performing their responsibilities. To the extent that FAA approves actions by others in the
aviation industry (airports, airlines, etc.), the orders apply to them as
well. Advisory Circulars are printed documents which provide useful
guidance and information often related to the FAR or FAA orders.
FAR Part 36
FAR Part 36 sets noise standards that aircraft must meet to obtain
type and airworthiness certificates for operation in the United States
[39]. First promulgated in 1969 for application to civil subsonic turbojets and large (over 12,500 lb) propeller-driven aircraft, the government subsequently amended the regulation to address civil
supersonic aircraft, small (not over 12,500 lb) propeller aircraft, and
rotary-wing aircraft such as helicopters. FAR Part 36 also prescribes
the procedures for aircraft manufacturers and others to use in measuring aircraft noise for certification purposes. The FAA publishes
companion Advisory Circulars which present measurement results
[25, 31, 38].
In 1977, the certification limits were made more stringent, leading
to the classification of aircraft into three groups known as stages. Stage 1
aircraft are those that were flying before the regulation was initially
adopted and were never required to meet level limits when they were
first issued. Stage 2 aircraft are those that met the original (1969) noise
emission limits but not the revised (1977) limits. Stage 3 aircraft are
those newest, quietest, types that must meet the revised limits.
The regulation requires that aircraft meet gross weight based
noise limits at three locations. Figure 14-8 shows the required measurement locations for turbojet and large propeller aircraft. These are
under the takeoff path 6500 m from brake release, under the approach
path 2000 m from runway threshold, and along the flight track sideline 450 m from the runway centerline (650 m for older turbojet aircraft). The sideline measurement is at the point of maximum sideline
noise. In practice this is normally to the side of takeoff, not landing.
609
610
Special Topics in Airpor t Planning and Design
SIDELINE MEASURING POINT
WHERE NOISE AFTER LIFTOFF
IS GREATEST
450 METERS
TAKEOFF
MEASURING
POINT
APPROACH
MEASURING
POINT
6500 METERS
2000 METERS
THRESHOLD OF RUNWAY OR
START OF TAKEOFF ROLL
FIGURE 14-8 FAR Part 36 noise measurement locations (Federal Aviation
Administration [39] ).
EFFECTIVE PERCEIVED NOISE LEVEL (EPNdB)
Figures 14-9 through 14-11 show the original Stage 2 noise limits
and the lower stage 3 limits for each of these three locations. Shown
with the limits are several examples of the actual certificated levels
for a variety of different aircraft. Note that some of the quieter types
include the McDonnell-Douglas DC-8-70 series, DC-9-80s (also
known as the MD-80), and the Boeing 757-200 and 767-200. FAR
Part 36 certification noise levels are published and regularly updated
in Advisory Circulars [25, 31, 38].
• CONCORDE
• DC-8-51
• 707-320B
120
110
STAGE 2 LIMIT
•
747SR
727-200
100
93
90
89
80
4-ENGINE
•
• DC-10-10
727-200-QN •
3-ENGINE
L-1011-500 • DC-10-30
•
DC-9-30 •
2-ENGINE
BAC-1-11-200
• • 737-200
• DC-5-71
• DC-9-50 • A-300B4
F-25 •
• BA• 148-200
• 757-200
• 757-200
• FALCON 20
CITATIONS
• • DHC-7
0
100
200
300
400
500
600
108
106
104
• 747SP
• 747-200 101
STAGE 3 LIMITS
700
800
900
MAXIMUM GROSS TAKEOFF WEIGHT (x 1000 LBS)
FIGURE 14-9 FAR Part 36 certification levels for takeoff noise (Federal Aviation
Administration [38] ).
EFFECTIVE PERCEIVED NOISE LEVEL (EPNdB)
Environmental Planning
120
• 707-320B
• CONCORDE
DC-5-51 •
737-200 •
DC-9-30 •
110
102
100
98
90
STAGE 2 LIMIT
• 727-200
DC-10-30 •
737-200QN •
•
727-200QN
•
• A-300B4
F-28 •
DC-9-30QN •
• 757-200 757-200
• DC-5-71
• BAC-1-11-200
•
• BA • 145-200
FALCON 20
DC-9-50
• DHC-7 •
• CITATION II
106
• 747SR
• 747-200
105
• 747SP
• DC-10-10
• L-1011-500
STAGE 3 LIMIT
80
0
100
200
300
400
500
600
700
800
MAXIMUM GROSS TAKEOFF WEIGHT (x 1000 LBS)
EFFECTIVE PERCEIVED NOISE LEVEL (EPNdB)
FIGURE 14-10 FAR Part 36 certification levels for approach noise (Federal Aviation
Administration [38] ).
120
STAGE 2 LIMIT
• CONCORDE*
110
DC-9-30
•
102
• 727-200
F-28
• • •• 727-200QN
100
DC-9-30QN
BAC-1-11-200
• 707-320B*
•DC-5-51*
• A-300B4
• DC-9-80 • 757-200• 757-200
• DC-5-71
94
106
STAGE 3 LIMIT
• 747-200
•
DC-10-30 • • 747SR*
• L-1011-500
• 747SP*
103
DC-10-10
FALCON 20
•
• BA • 146-200
• CITATION II
DHC-7
•
90
* 0.35 N. MI FOR STAGE 2
FOUR-ENGINE AIRPLANES
80
0
100
200
300
400
500
600
700
900
MAXIMUM GROSS TAKEOFF WEIGHT (x 1000 LBS)
FIGURE 14-11 FAR Part 36 certification levels for sideline noise (Federal Aviation
Administration [38] ).
FAR Part 91
FAR Part 91 limits civil aircraft operations in the United States based
on FAR Part 36 certification status. The noise elements of FAR Part 91
were first adopted in 1977. This regulation prohibits operation of civil
subsonic turbojet aircraft with maximum weights over 75,000 lb
unless they were certificated under FAR Part 36 Stage 2 or 3 limits.
FAR Part 91 has led to the elimination and ongoing prohibition of all
Stage 1 operations in the United States in civil subsonic turbojets over
611
612
Special Topics in Airpor t Planning and Design
75,000 lb but does not affect aircraft of 75,000 lb or less which are
primarily corporate aircraft.
In 1990, the federal government enacted the Airport Noise and
Capacity Act of 1990 (Public Law 101-508). This act called for the FAA
to develop a national aviation noise policy and regulations to implement the policy. This was accomplished, in part, by amending FAR
Part 91 to require the phased elimination of Stage 2 operations in civil
subsonic turbojets over 75,000 lb by the end of 1999 with limited
waivers through 2003. This will leave only Stage 3 aircraft operating
in the air carrier fleet in the near future.
The interim compliance schedule of FAR Part 91 required that aircraft operators remove 25 percent of their Stage 2 airplanes by the end
of 1994, 50 percent by 1996 and 75 percent by 1998 or, alternatively,
phase-in Stage 3 airplanes to achieve a fleet mix of 55 percent Stage 3
by 1994, 65 percent by 1996 and 75 percent by 1998. The balance of the
FAA national noise policy required by the Airport Noise and Capacity
Act is embodied in FAR Part 161 which is discussed later.
FAR Part 150
The Aviation Safety and Noise Abatement Act of 1979 (Public Law
96-193) required the FAA to establish regulations that set forth
national standards for identifying airport noise and land-use incompatibilities and develop programs to eliminate them. The FAA promulgated these regulations as FAR Part 150 [6].
FAR Part 150 prescribes specific standards and systems for
1. Measuring noise
2. Estimating cumulative noise exposure using computer
models
3. Describing noise exposure including instantaneous noise
levels, single event levels and cumulative exposure
4. Coordinating noise compatibility program development with
local land-use planning officials and other interested parties
5. Documenting the analytical process and development of the
compatibility program
6. Submitting documentation to the FAA
7. FAA and public review processes
8. FAA approval or disapproval of the submission
A full FAR Part 150 submission consists of two basic elements,
namely, a noise exposure map (NEM) and its associated documentation, and a noise compatibility program (NCP). It is possible, however,
to submit only the NEM. In addition to these elements, a critical
ingredient to a successful FAR Part 150 program is a thorough and
effective public involvement program.
Environmental Planning
Noise Exposure Map
The Noise Exposure Map (NEM) document describes the airport
layout and operation, aircraft-related noise exposure, land uses in
the airport environs, and the resulting noise-related land-use compatibility situation. It addresses the year of submission and five years
into the future. It includes graphic depiction of existing and future
noise exposure resulting from aircraft operations, and of land uses in
the airport environs. Documentation must accompany the noise
exposure map that describes the data collection and analysis undertaken in its development. The basic output of the map development
is identification of existing and potential future noise and land-use
incompatibilities. FAR Part 150 includes a table presenting noise and
land-use compatibility guidelines, shown earlier in Table 14-2.
Noise Compatibility Program
Following development of a NEM, which essentially defines the
extent of noise and land-use incompatibility, the airport proprietor
may elect to develop a Noise Compatibility Program (NCP). In developing a noise compatibility program, the airport proprietor must
consider all potential compatibility measures, including the airport
layout, operational and use alternatives, and land use alternatives.
FAR Part 161, discussed next, further regulates the evaluation and
adoption of airport use restrictions. The ultimately developed program is essentially a list of the actions the airport proprietor proposes
to undertake to minimize existing and future noise and land-use
incompatibilities. The noise compatibility program documentation
must recount the development of the program, including a description of all measures considered, the reasons that individual measures
were accepted or rejected, how measures will be implemented and
funded, and predicted effectiveness of individual measures and the
overall program.
Following FAA acceptance of the NEM and approval of the NCP
program submissions, the airport operator may apply for FAA funding of program implementation. Official FAA approval of the NCP
does not eliminate the requirements for a formal environmental
assessment of any proposed actions pursuant to requirements of the
National Environmental Policy Act (NEPA) [2, 43], however, acceptance of the submission is a prerequisite to application for funding of
implementation actions.
Public Involvement
At every stage of the FAR Part 150 planning process opportunities
exist to apprise airport neighbors, user groups, and local officials of
project alternatives, and to solicit their comments, criticism, and
support. A key objective is to utilize the broadest possible definition
of the airport public which includes more than just the residents of
areas around the airport. A balanced discussion of issues must
613
614
Special Topics in Airpor t Planning and Design
include representatives of the aviation industry including local, state,
regional, and national agencies with jurisdiction, the business community, and individual airport users. Successful public information
programs include the following elements:
1. Regular advisory committee meetings
2. Technical and other subcommittee meetings as required
3. Informational newsletters tailored for public distribution
4. Informal workshops open to the general public
5. A final public hearing
6. Briefings to local public officials
FAR Part 161
The second major element of the national noise policy enacted
through the Airport Noise and Capacity Act of 1990 is FAR Part 161.
It establishes requirements that an airport operator must meet prior
to promulgating any airport noise or access restriction on the use of
Stage 2 or Stage 3 aircraft [40].
Under FAR Part 161 an airport proprietor may impose restrictions on Stage 2 aircraft operations as long as two conditions are met.
First, the proprietor must prepare an analysis of the anticipated costs
and benefits of the proposed restriction. Second, the proprietor must
provide proper notice of the restriction to the public and to affected
parties. The cost-benefit analysis required by FAR Part 161 must
include
1. An analysis of the anticipated or actual costs and benefits of
the proposed restriction
2. A description of alternative restrictions which were considered
3. A description of the alternative measures considered that do
not involve airport restrictions
4. A comparison of the costs and benefits of the alternative
measures which were considered
FAR Part 161 imposes substantial impediments to local restrictions
on Stage 3 aircraft. No local Stage 3 restriction may become effective
unless it has been submitted to and approved by the FAA. The process
for FAA review and approval has three principal elements [5]:
1. The collection and analysis of data to justify the restriction
and to explain its environmental and economic impact
2. The notification of the public and allowance of adequate time
for comment on the proposed restriction
3. The submission of the restriction for FAA review and approval
Environmental Planning
An airport cannot implement a stage 3 aircraft restriction unless it
complies with each of the above elements.
FAR Part 161 stipulates that both types of restrictions may be
developed through the FAR Part 150 process. The benefit of using
FAR Part 150 as a mechanism for developing a rule restricting airport
access is the availability of federal funding. Since such federal funding may be used for the preparation of a FAR Part 150 NCP, this funding can be used for the preparation of any noise or access restriction
that is included in the FAR Part 150 study. The major disadvantage of
submitting Stage 2 restrictions to the FAA as part of the FAR Part 150
submission is that a formal submission will invoke the approval process which is otherwise not necessary under FAR Part 161. Stage 3
restrictions, on the other hand, require FAA review whether or not
they are developed during a FAR Part 150 process.
Construction Impacts
The construction of facilities at airports can result in temporary and
long-term impacts on the community and travelers. Those factors
which are of primary concern during the construction process include
soil erosion, water and air quality, noise due to construction equipment and methods, the source and quantity of construction materials,
disruption and relocation of businesses and residences, the continued
operation of existing facilities both on and off-airport during the
construction process, and the interference with other construction
projects [23].
A review of the environmentally sensitive areas and facilities
should be undertaken to identify those which will be subject to impact
and the likely duration and consequences of these activities. The location and quantity of cut and fill must be identified and methods to
minimize the effect of construction activities on soil erosion during
construction should be identified. Procedures for the handling of
construction materials and wastes to minimize the introduction of
particulate matter into the air and water resources are required. Those
land uses which will be adversely affected by noise from construction
activities should be identified and the optimal routing of construction
vehicles and timing of activities chosen to minimize damage. Obvious positive impacts of a major construction activity are the increases
in employment and payroll for personnel associated with the project
and the purchase of materials and supplies from local firms which
support the local economy. However, certain businesses and residences in the vicinity of the project may be subject to disruption due
to the possible rerouting and congestion of vehicular traffic and
restrictions on access to land uses.
The study of the direct and indirect socioeconomic impacts on the
community should include an identification of the location, timing,
and amount of impact throughout the entire construction period.
615
616
Special Topics in Airpor t Planning and Design
Social Factors
Land Development
The development of an airport can result in a change in the pattern
of land use activity both in the vicinity of the airport and in the
geographic region. These land development activities may result in
changes in the level of economic activity and population growth and
demography. The location of an airport generally results in the
inducement of land development in the vicinity of the of the airport
which may be measured in terms of the density of industrial, commercial, retail, agricultural and residential use. It usually impacts the
nature, magnitude, and operating patterns of other transportation
modes providing access to the airport and those land uses associated
with its development. The presence of the airport may induce industrial or commercial activities to move into or expand within the
region due to increased accessibility to markets and materials.
An airport will affect land development as a function of its direct
economic impact on the region. The following land development
activities should be studied [2, 43]:
1. Plant relocation from outside the region which will require
construction activities
2. Increases in the production or sales of existing business enterprises requiring new or expanded capital facilities
3. Increased expenditures in tourist and recreational facilities
resulting in requirements for new or expanded facilities and
increases in retail sales
4. Expansion of agricultural markets resulting in increased productivity and resource utilization
5. Increased demand for specialized facilities for such activities
as business or convention centers
6. Expansion of commercial and financial markets resulting in a
demand for additional facilities
The study of the land development impacts requires an analysis
of those factors which influence industrial, commercial, and residential location decisions including accessibility to raw materials, labor,
and markets, the costs of production and transportation, and those
quality of life and community factors associated with such decisions. The analysis is usually conducted through an examination of
historical trends for the area and similar locations and use surveys
and economic models to predict land development. The study
should identify the nature and extent of existing zoning ordinances
in the vicinity of the airport and recommend changes necessary to
Environmental Planning
accommodate the likely development in a compatible manner. The
study should also identify those requirements for regional policy
decisions needed to stimulate overall land development in accordance with the stated objectives of the communities affected.
Displacement and Relocation
The construction or expansion of an airport often creates a need for
additional land, the relocation of residences, businesses, and community facilities, a disruption in business activity and community
character and cohesiveness, the impairment of community service
functions, and an increased demand for public services. The assessment is directed toward determining the type, extent, characteristics,
and effects of displacement and relocation and mitigation measures
to minimize adverse consequences.
The boundaries of the areas affected are determined from area
maps. The community structure is usually defined in terms of population demography, growth, and density, housing and business characteristics such as the type, distribution, condition, value, occupancy
and vacancy levels, open land, recreational resources, and community services. The availability of relocation resources for those land
uses required for airport and ancillary activities are identified and the
changes in the demand for public services are quantified. Comparisons of the relative impact of project alternatives are usually made
which attempt to address the following items [43]:
1. The nature, location, and extent of the displacement of homes,
businesses, and community facilities
2. The creation of physical barriers or divisions
3. The impairment of mobility, accessibility, community services,
and community facilities
4. The disruption of homes, businesses, and community facilities during construction
5. The nature, availability, adequacy, and compatibility of relocation resources
6. The nature, location, and extent of land use changes
7. The aesthetic appeal of the design for the facility and surrounding environment
Parks, Recreational Areas, Historical Places, Archeological
Resources, and Natural and Scenic Beauty
Particular attention is required to determine the impact upon parks,
recreational areas, open spaces, cultural and historic places, archeological resources, and natural and scenic beauty. The analyst must
617
618
Special Topics in Airpor t Planning and Design
identify the type of facilities which will be impacted, their size and
use, and those measures which can be implemented to preserve the
nature, character, compatibility, and accessibility of the facilities. It is
particularly important to document the relative impact of project
alternatives on these types of facilities and to avoid the acquisition of
such lands for the implementation of a project alternative.
The assessment can be performed on the basis of a participatory
evaluation with those groups which possess expertise or interest
in this impact area. Suggested generalized evaluation criteria might
include [2, 43]:
1. The existence, nature, and extent of any physical alteration to
the facilities
2. The degree of conformity of the planned facilities with the
existing environment
3. The disruption of access
4. The disruption of the ambient environment
5. The compatibility of access induced development with the
facilities
Consistency with Local Planning
The planning and design of airports can have significant effects on
the economy, land use, infrastructure, and nature of community
development. The planning effort must be carried on in an environment which is compatible and coordinated with other local planning
efforts and guidelines. Care must be exercised from the inception of
planning to assess the impact of project alternatives and operations
on the goals and objectives of communities and to identify those facets of the project which may present conflicts between existing plans
or community goals. Modifications to airport project proposals which
will be in conformity with local policies and plans must be explicitly
examined. Policies required to preserve the overall development
objectives of the community should be identified and mechanisms to
implement such policies proposed.
The assessment of impacts in this area requires an identification of
and coordination with those federal, state, and local agencies which
have a concern or jurisdiction in matters related to airport and community development actions, the delineation of clear statements of goals
and objectives, the integration of airport plans with local comprehensive land use, economic, and transportation development plans, and
the establishment of a continuing dialogue on issues related to these
plans. The presentation of the results of planning efforts and development recommendations in public forums, with mechanisms for citizen
participation in the planning and review process, together with timely
and well documented responses to community concerns is essential.
Environmental Planning
Ecological Factors
Wildlife, Waterfowl, Flora, Fauna, Endangered Species
The consideration of the impact of airport development on changes
in the natural state of land and waterways is essential to protect ecosystems. Living and nonliving elements, plants, and animals all interact on land and in water to produce a highly interdependent system
of aquatic and terrestrial ecosystems. The relationship between species and the ecosystem is essential to maintain the life support system
for wildlife, waterfowl, flora, fauna, and endangered species [20, 51,
52]. Of particular importance is vegetation, plant and animal life. The
principal impacts which may occur are the loss of or injury to the
organisms or the loss or degradation of the ecosystem.
The use of land for airport development creates disturbances and
disruptions to flora and fauna. The specific project elements often
include the clearing and grubbing of land areas, changes in the composition and nature of the topography, and interferences with water
shed patterns. Thus airports can destroy the natural habitat and feeding grounds of wildlife and eliminate or reduce flora essential to the
maintenance of the ecological balance in the area. Particular hazards
may be presented to birds and aircraft due to striking birds, and care
must be exercised in choosing airport sites to avoid land which
attracts birds and natural migration routes. The protection for endangered species in the United States is legislated through the contents of
the Endangered Species Act of 1973 (Public Law 93-205) and lists of
endangered species are published [20, 51, 52]. Reference should also
be made to state and location regulations in this regard.
The assessment techniques used include the identification of the
important aquatic and terrestrial organisms present in the area and a
determination of the life support systems required for the different
species. An analysis is performed to determine the impacts on vegetation requirements, food chains, and habitats of these species, as
well as their tolerance to air and water pollution. Care must be taken
in the case of aquatic species to examine the effects of soil erosion,
flooding, and sedimentation on stream beds where food chains,
spawning grounds, and habitats exist.
Wetlands and Coastal Zones
Improperly planned or operated drainage systems at airports can
cause contaminants to enter streams, lakes, and waterways. The normal operation of an airport results in contamination potential through
aircraft and ground vehicle washing, servicing, and fueling, airport
and aircraft maintenance, and terminal services. In the construction
phase of a project there is a high potential for contamination through
clearing, grubbing, pest control, and changes in topography. Changes
619
620
Special Topics in Airpor t Planning and Design
in the natural drainage patterns of the area are very common due to
the nature of airport development projects. Preservation of recharge
areas and stream flows, the elimination of flooding and sedimentation problems, and the preservation of the quality and routing of
water resources are all vitally essential to the maintenance of water
quality and the protection of ecosystems.
Flood Hazards
The flood hazard potential of any development is a necessary consideration since alterations in the topography, cover, and soil characteristics on the property are inevitable. The storage capacity of local
rivers, streams, canals, and groundwater areas can be exceeded due
to changes in the magnitude and paths of runoff from storms and
high rainfall or thawing events. The analysis of the potential for
flooding is conducted by evaluating the characteristics of the ground
surface, soil materials, topography, and floodplains, the historical
frequency and intensity of storms, and storm water drainage and
retention facilities. The methods for conducting such analyses are
discussed in Chap. 9.
If it is found that the project design increases the potential for on
or off-site flooding, those areas subject to these effects are identified
and the mechanisms required to alleviate the hazards are incorporated into the project design. The construction of new or increased
capacity storm sewers and impounding areas, channels, and dikes
are most commonly indicated. Changes in the elevation of facilities
and the slope and cover of the ground surface at the site can also be
of considerable benefit in reducing flood hazards.
Engineering and Economic Factors
Costs of Construction and Operation
All engineering planning studies consider the capital, maintenance,
and operating costs of all feasible alternatives as an integral part of
the planning process. For airport projects these costs include land
acquisition, purchases of land leases and covenants to protect aircraft
operations and environmental quality, facility construction, operating, maintenance, and administrative costs. Typically, construction
costs are derived from quantity takeoffs of materials which are related
to locally appropriate cost indices for the various construction items
[13, 18, 19]. The relationship between the overall cost factor is related
by a concept of bench mark cost indices for various components of
the terminal building [50]. A tabulation of these indices is given in
Table 14-4. The capital costs usually include materials, supplies, labor,
and engineering.
Benchmark Index per Unit
Location
Terminal
Terminal
Terminal or
connector
Area Category
Type A:
Passenger-handling
facilities
Area Type
ft
Lobbies
Waiting rooms
Circulation
Rest rooms
Counter areas
Baggage claim facilities, including
claim device
7. Service and storage areas
1.
2.
3.
4.
5.
6.
1.
Type B:
2.
Airline/tenant
operations space, partly
finished
3.
4.
5.
Type C:
Airline operations
space, lower level
unfinished
Cost Unit Shell
Customer service offices
Agent supervisor offices,
checkout, and agent lounge
Toilets
VIP/IPR rooms
Lost and found
2
ft2
621
ft2
1. Offices
2. Tire shop (including equipment)
3. Storerooms
4. Ready and lunch rooms
5. Lockers
6. Toilets
7. Planning center and load planning
TABLE 14-4 Unit-Cost Indices for Space and Special Equipment at Airport Terminal Buildings
1.00
Tenant
NA
Total Cost
∗
2.00
0.50
3.00
1.50
NA
0.65
0.60
0.40
0.50
1.05
1.15
1.55
1.10
0.72
2.20
1.75
1.37
0.55
0.62
0.30
0.43
0.20
1.80
0.85
1.15
1.22
0.90
1.03
0.80
2.40
1.45
622
Benchmark Index per Unit
Location
Connector
Area Category
Type D:
Passenger-handling
Area Type
1.
2.
3.
4.
Corridors
Rest rooms
Service and storage area
Boarding areas
Cost Unit Shell
ft
2
0.80
∗
Tenant
Total Cost
NA
0.26
1.06
NA = not applicable.
These cost data have been compiled for new terminal and concourse construction, and they may not be applicable for remodeling or small additions to
existing facilities. They do not include installed equipment, such as loading bridges, claim devices, ramp utilities, and so on.
Source: Federal Aviation Administration [50].
TABLE 14-4 Unit-Cost Indices for Space and Special Equipment at Airport Terminal Buildings (Continued)
Environmental Planning
The construction costs for the various items are normally made at
different points in time and, therefore, for comparative and evaluative purposes these are brought back to some common point in time
in order that value may be properly attributed to the construction
needs. The operating, maintenance and administrative costs are usually annualized. These costs are normally estimated through comparisons with similar installations, historical trends, and economic
influences. The costs of capital and the required coverage are also
included to arrive at the total program cost.
An overview of the categories and items typically found in airport
projects for which capital, operating, maintenance, and administrative
cost estimates are required includes:
1. Airfield facilities
a. Runways, taxiways, and aprons
b. Fueling and fixed power systems, crash, fire and rescue
units
c. Air traffic control facilities, lighting, and navigational aids
2. Terminal building facilities
a. Terminal buildings and connectors
b. General aviation servicing buildings and hanger areas
c. Boarding devices, mechanical and electrical systems
d. Communications and security systems
e. Air cargo buildings
f. Maintenance and administrative buildings
g. Furnishings
3. Access facilities
a. Roadways, drives, and curb frontage
b. Rental car, limousine, and transit areas
c. Parking lots and garages
d. Graphics, signage, and lighting
4. Infrastructure facilities
a. Landscaping and drainage
b. Utilities including water supply, sewage disposal, power
supply systems
c. Land acquisition
For the purposes of evaluation these costs are usually related to passenger and aircraft traffic characteristics such as the cost per enplaned
passenger or cost per air carrier operation. The costs are also allocated
623
624
Special Topics in Airpor t Planning and Design
among the various users and nonusers of the project, normally tenants,
concessionaires, airlines, general aviation, cargo businesses, federal,
and state, and local governmental agencies as appropriate.
Economic Benefits and Fiscal Requirements
The evaluation of the economic and financial feasibility of the
project requires and identification of both the level and allocation of
the benefits and costs of the project, as well as a revenue analysis
performed for the various cost centers. Both direct and indirect benefits can accrue to the users of the airport and to the community in
which the airport is located. Generally user benefits include reductions in delay, fuel consumption, time, and other operating and
maintenance costs. These can usually be derived relative to dollar
value. Nonuser and community benefits take the form of increased
economic activity, rises in employment, and purchases of goods and
services. These can also be evaluated through classical economic
techniques [2, 8, 21].
Although it may be possible to justify expenditures from an economic standpoint, it may not be possible to generate or capture the
value of these benefits from a revenue viewpoint. A revenue analysis
seeks to identify the revenue requirements by cost center and the
level of revenue required to cover project costs. Normally, the costs
are allocated to facility users and rents, rate and charges, and concession agreements are negotiated on the principle that all users should
pay their fair and proportionate share of the costs of providing, maintaining, operating, and administering the facilities they use.
Various indices are used to determine the reasonableness of revenue requirements including the percentage of revenue generated
which is paid for terminal rents or landing fees, and the revenue
required per enplaned passenger. A comparison of the bonding
capacity of the governmental units concerned with the project is
vital in order to determine the influence of the project on other public
revenue requirements.
Energy and Natural Resources
The use of new technology in power generation systems at airports,
the efficient layout of apron areas and taxiing routes, improvements
in the capacity of runway systems, the installation of navigational
aids, and the effective uses of construction materials can substantially
reduce the costs and resource use of energy. A detailed examination
of the impact of airport design elements on energy consumption
should be performed. Typically comparisons between existing and
planned systems, and between alternative systems for proposed facility
modifications relative to fuel consumption of aircraft and terminal
systems may yield essential information concerning their feasibility
and merit.
Environmental Planning
Summary
Though the incentive for the study of environmental, sociological,
and ecological factors in the evaluation of engineering projects was
initially provided through national, state, and local legislation, the
state of the art has evolved to the point that a better and more complete understanding of the short- and long-term implications of these
projects is leading to more efficient engineering designs. True the
costs of planning have increased because of the need to study several
criteria in the evaluation of planning proposals, but the potential for
the overall reduction in the real costs of these proposals on the longterm requirements of society through the use of comprehensive planning approaches has also been increased.
References
1. Acoustic Determination of Occupational Noise Exposure and Estimation of NoiseInduced Hearing Impairment, Publication 1999, International Organization for
Standardization, Geneva, Switzerland, 1990.
2. Airport Environmental Handbook, Order No. 5050.4A, Federal Aviation
Administration, Washington, D.C., 1985.
3. Airport Landscaping for Noise Control Purposes, Advisory Circular AC
150/5320-14, Federal Aviation Administration, Washington, D.C., 1978.
4. Airport Master Plans, Advisory Circular AC 150/ 5070-6A, Federal Aviation
Administration, Washington, D.C., 1985.
5. Airport Noise: A Guide to the FAA Regulations under the Airport Noise and Capacity
Act, Cutler and Stanfield and Harris Miller Miller and Hanson, Inc., Lexington,
Mass., January 1992.
6. Airport Noise Compatibility Planning, Part 150, Federal Aviation Regulations,
Federal Aviation Administration, Washington, D.C., 1991.
7. Airport Noise Compatibility Study, Greater Pittsburgh International Airport,
Aviation Planning Associates, Cincinnati, Ohio, 1986.
8. Airport Planning and Environmental Assessment, Notebook Series, 4 Vols., DOT
P 5600.5, Department of Transportation, Washington, D.C., 1978.
9. Airport Planning Manual, Part 2, Land Use and Environmental Control, 2d ed.,
Document No. 9184-AN/902, International Civil Aviation Organization,
Montreal, Canada, 1985.
10. Analysis of the Predictability of Noise-Induced Sleep Disturbance, K. S. Pearsons,
D. S. Barber, and B. G. Tabachnick, Report No. HSD-TR-89-029, U.S. Air Force,
Washington, D.C., 1989.
11. “Applied Acoustical Report: Criteria for Assessment of Noise Impacts on
People,” L. S. Finegold, C. S. Harris, and H. E. Von Gierke, submitted to Journal
of Acoustical Society of America, New York, N.Y., 1992.
12. Aviation Noise Effects, S. J. Newman, Report No. FAA-EM-85-2, Federal Aviation
Administration, Washington, D.C., 1985.
13. Building Construction Cost Data, R. S. Means Company, Inc., Duxbury,
Mass.
14. Chicago Delay Task Force Technical Report, Vol. I: Chicago Airport/Airspace
Operating Environment, Landrum and Brown Aviation Consultants, Chicago, Ill.,
April 1991.
15. Citizen Participation in Airport Planning, Advisory Circular AC 150/5050-4,
Federal Aviation Administration, Washington, D.C., 1975.
16. Community Noise, Wyle Laboratories, Report No. DOT-NTID300.3, Office
of Noise Abatement and Control, U.S. Environmental Protection Agency,
Washington, D.C., 1971.
625
626
Special Topics in Airpor t Planning and Design
17. Compilation of Air Pollution Emission Factors, Report No. AP-42, Environmental
Protection Agency, Washington, D.C., Periodically Revised.
18. Dodge Guide for Estimating Public Works Construction Costs, McGraw-Hill
Information Systems Company, New York, N.Y.
19. Dodge Manual for Building Construction Pricing and Scheduling, McGraw-Hill
Information Systems Company, New York, N.Y.
20. Endangered and Threatened Wildlife and Plants, Fish and Wildlife Service, Department
of the Interior, Washington, D.C.
21. Environmental Assessment Notebook Series, Report No. DOT P5600.4,
7 Volumes, Department of Transportation, Washington, D.C., 1975.
22. “Environmental Considerations in Airport Planning,” C. V. Robart, Course
Notes for Airport Planning and Design Short Course, University of California,
University Extension, Berkeley, Calif., June 1977.
23. Environmental Impact Assessment Report for the Expansion of the Existing
Terminal Complex at the Fort Lauderdale-Hollywood International Airport,
Aviation Division, Broward County Department of Transportation, Fort
Lauderdale, Fla., 1980.
24. Environmental Protection, Annex 16 to the Convention on International Civil
Aviation, Vol. 1: Aircraft Noise, 2d ed., International Civil Aviation Organization,
Montreal, Canada, 1988.
25. Estimated Airplane Noise Levels in A-Weighted Decibels, Advisory Circular AC
36-3F, Federal Aviation Administration, Washington, D.C., 1990.
26. Federal Agency Review of Selected Noise Analysis Issues, Federal Interagency
Committee on Noise (FICON), Washington, D.C., 1992.
27. General Operating and Flight Rules, Part 91, Federal Aviation Regulations, Federal
Aviation Administration, Washington, D.C., 1992.
28. Information on Levels of Environmental Noise Requisite to Protect Public
Health and Welfare with an Adequate Margin of Safety, U.S. Environmental
Protection Agency, Arlington, Va., 1974.
29. INM Integrated Noise Model Version 3, User’s Guide, Report No. FAA-EE81-17, Office of Environment and Energy, Federal Aviation Administration,
Washington, D.C., 1982.
30. Management of Airport Industrial Waste, Advisory Circular AC 150/5320-15,
Federal Aviation Administration, Washington, D.C., 1991.
31. Measured or Estimated (Uncertified) Airplane Noise Levels, Advisory Circular AC
36-2C, Federal Aviation Administration, Washington, D.C., 1986.
32. Measures of Noise Level: Their Relative Accuracy in Predicting Objective and
Subjective Responses to Noise During Sleep, J. S. Lucas, Report No. EPA- 600/
1-77-010, Environmental Protection Agency, Washington, D.C., 1977.
33. Noise, Environmental Health Series No. 12, World Health Organization, Geneva,
Switzerland, 1980.
34. Noise Abatement Departure Profiles, Advisory Circular AC 91-53, Federal Aviation
Administration, Washington, D.C., 1978.
35. Noise Certification Handbook, AC 36-4B, Federal Aviation Administration,
Washington, D.C., 1988.
36. Noise Control and Compatibility Planning for Airports, Advisory Circular AC
150/5020-1, Federal Aviation Administration, Washington, D.C., 1983.
37. “Noise-Induced Sleep Disturbance and Their Effect on Health,” B. Griefahn and
A. Muzet, Journal of Sound and Vibration, Vol. 59, No. 1, New York, N.Y., 1978.
38. Noise Levels for Certified and Foreign Aircraft, Advisory Circular AC 36-1F, Federal
Aviation Administration, Washington, D.C., 1992.
39. Noise Standards: Aircraft Type and Airworthiness Certification, Part 36,
Federal Aviation Regulations, Including Changes 1 to 21, Federal Aviation
Administration, Washington, D.C., 1991.
40. Notice and Approval of Airport Noise and Access Restrictions, Part 161, Federal
Aviation Regulations, Federal Aviation Administration, Washington, D.C., 1991.
41. “Occupational Noise Exposure; Hearing Conservation Amendment,” Federal
Register 48(46), Occupational Safety and Health Administration, Washington,
D.C., 1983.
Environmental Planning
42. Physiological, Psychological and Social Effects of Noise, K. D. Kryter, Reference
Publication 1115, National Aeronautics and Space Administration, Washington,
D.C., 1984.
43. Policies and Procedures for Considering Environmental Impacts, Order No. 1050.1D,
Federal Aviation Administration, Washington, D.C., 1986.
44. Public Health and Welfare Criteria for Noise, U.S. Environmental Protection
Agency, Arlington, Va., 1973.
45. Recommended Method for Computing Noise Contours Around Airports, Circular-205
AN1/25, International Civil Aviation Organization, Montreal, Canada, 1988.
46. “Research on Noise-Disturbed Sleep Since 1973,” B. Griefahn, Proceedings,
The Third International Congress on Noise as a Public Health Problem, ASHA
Report No. 10, Frieburg, West Germany, 1980.
47. Special Report: Summary of Significant Provisions of the Final FAA Noise Rule, Airports
Association Council International-North America, Washington, D.C., 1991.
48. Study of Soundproofing Public Buildings Near Airports, Wyle Laboratories, Report No.
DOT-FAA- AEQ-77-9, Federal Aviation Administration, Washington, D.C., 1977.
49. “Synthesis of Social Surveys on Noise Annoyance,” T. J. Schultz, Journal of the
Acoustical Society of America, Vol. 64, No. 2, New York, N.Y., 1978.
50. The Apron and Terminal Building Planning Report, Report No. FAA-RD-75-191,
Federal Aviation Administration, Washington, D.C., July 1975.
51. Threatened Wildlife of the United States, Fish and Wildlife Service, Department of
the Interior, Washington, D.C.
52. United States List of Endangered Fauna, Fish and Wildlife Service, Department of
the Interior, Washington, D.C.
627
This page intentionally left blank
CHAPTER
15
Heliports
Introduction
A rotorcraft is a rotary winged aircraft that can lift vertically and sustain
forward flight by power-driven rotor blades turning on a vertical axis.
The helicopter is a vehicle which essentially can take off from and land
in a nearly vertical direction. This is known as vertical takeoff and
landing (VTOL). Since the helicopter is by far the most advanced and
utilized of the vertical takeoff aircraft, the emphasis on this chapter is on
ground facilities for helicopters and other rotary wing type aircraft,
referred to as heliports.
Heliports
A heliport is defined as an identifiable area on land, water, or structures,
including buildings or facilities, used or intended to be used for the landing and takeoff of helicopters or other rotary wing type aircraft [10]. A
helideck is a heliport located on a floating or an off-shore structure. A helistop is defined as an area developed and used for helicopter landings and
takeoffs to drop-off or pickup passengers or cargo. A helipad is defined as
a paved or other surface used for parking helicopters at a heliport.
The Nature of Helicopter Transportation
Helicopters are used for a variety of aviation activities including aerial
observation, sightseeing, agricultural application, law enforcement, fire
fighting, emergency medical services, transporting personnel and supplies to offshore oil rigs, traffic and news reporting, corporate and business transportation, personal transportation, and heavy lifting. Helicopters are also extensively used in military operations throughout the
world. Transportation by helicopter can generally be classified into two
general categories, namely, private operations and commercial operations. Private operations are of the same nature as general aviation and
commercial operations are similar to scheduled air carrier activity.
Most of the helicopters used in private operations have a capacity
of 1 to 5 persons and have maximum gross weights between 3000 and
6000 lb. Helicopters in commercial operations are of greater capacity,
629
630
Special Topics in Airpor t Planning and Design
typically between 10 and 50 passengers, and have maximum gross
weights between 10,000 and 50,000 lb. Primarily because of the difference in size, heliport facilities for private operations are normally
much smaller than those for commercial operations.
Private operations include construction, forest and police patrol,
crop dusting, advertising, emergency medical service and rescue, and
transport to off-shore oil well locations. Commercial operations may
be classified into two types. One is transportation in large metropolitan
areas between several airports in the region and between airports and
the business center in the region. The second is intercity transportation between cities not necessarily in the same metropolitan area.
Experience to date shows that the helicopter has achieved its
greatest success in the first type of service, the operating service area
being within a radius of about 50 mi. The continued development of
the second type of service will depend on the ability of helicopters to
compete favorably with fixed-wing aircraft with respect to speed and
economics over stage lengths up to about 300 mi.
Despite the growth of transport by helicopter, it only accounts for
a small percentage of the total number of persons traveling by air.
Helicopter operating costs have gradually been reduced but they are
still considerably higher than those for fixed-wing aircraft.
Characteristics of Helicopters
A helicopter is a powered aircraft which gains its lift from the rotary
motion of airfoil surfaces. The distinctive characteristic of a helicopter is
its ability to hover through application of power to the rotating airfoils.
The practical consequences of this characteristic are a much greater
range of flight speeds and flight attitudes than is the case with conventional aircraft and the ability to land on and takeoff from comparatively
small areas. When on the ground, helicopters have the ability of taxiing
under their own power. Helicopters in private operation typically have
cruise speeds between 90 and 130 kn, ranges between 300 and 400 nm,
and passenger capacities between 2 and 10. Helicopters in the transport
category typically have cruise speeds from 100 to 150 kn, ranges between
300 and 700 nm, and passenger capacities between 10 and 50.
While helicopters can ascend vertically from the ground, prolonged vertical ascents severely restrict load-carrying capacities. The
usual procedure is to employ vertical ascent only to initiate the takeoff. As with other aircraft, takeoffs are usually made into the wind.
The initial vertical rise for takeoff is aided by a ground cushion built
up by the pressure of the air directed against the ground by the
revolving rotors. After a few feet of vertical ascent, horizontal acceleration is begun until climb-out speed is reached. Prior to reaching
climb-out speed, the helicopter can be flown in a horizontal path or in
a slightly ascending path. Climb-out and descent speeds vary from 30
to 60 kn. Just before touchdown, the helicopter hovers momentarily 5
to 10 ft above the landing pad.
Heliports
From a safety standpoint, the operation of single-engine helicopters requires that emergency landing areas be available along the entire
flight path. In case of engine failure, safe landings using autorotation
can be made if space is available. Autorotation is the continuation of
rotor rotation in flight after cessation of power. Sufficient height must
be reached by the helicopter in order to utilize the principle of autorotation. Twin-engine helicopters, on the other hand, are designed to permit continuation of flight and even a moderate rate of climb in the
event once the engine fails. For these types of helicopters, it is not necessary from a safety standpoint to have space available for emergency
landing along the entire route. Virtually all small helicopters in private
operation are single engine. Most of the helicopters, with the exception
of a few models, are also single engine. Twin-engine helicopters are
not, however, designed to hover with only one engine in operation. On
takeoff, therefore, in the event an engine fails before the helicopter has
reached a one-engine-out flight speed, a landing must be made. To take
care of this eventuality, sufficient space must be provided ahead of the
landing area for an emergency landing. The single-engine helicopter
also needs this area, but in addition requires space for emergency landings all along the flight path. If helicopters are designed to hover with
one engine out, space ahead of the landing area is not required.
Because it is not economically practical for a helicopter to ascend
and descend vertically, unobstructed approach-departure paths leading to the heliport are required. To protect the approach-departure
path, obstructions are not permitted to extend above a prescribed
inclined plane, an approach surface, beginning at the heliport and
extending to specified distance from the heliport. The obstruction
clearance requirements specified by the FAA are discussed later and
ICAO has adopted similar recommendations.
Helicopters can be either single-rotor or tandem rotor and powered by one or two engines. The landing gear can consist of pontoons
for landing on water, skids, or wheels equipped with rubber tires.
When wheels are used, the landing gear normally consists of two main
wheels and a single nose or tail wheel, or four wheels. Figure 15-1
shows several small utility helicopters at the Port Authority of New
York and New Jersey heliport on the East River in New York City.
The principal dimensions of representative helicopters used for private and commercial operations are shown in Fig. 15-2 and tabulated
in Table 15-1.
Factors Related to Heliport Site Selection
The selection of a heliport site in an urban area requires the consideration of many factors, the most important of which are:
1. The best locations to serve potential traffic
2. The provision of minimum obstructions in the approach and
departure areas
631
632
Special Topics in Airpor t Planning and Design
FIGURE 15-1 Port Authority of New York and New Jersey heliport (Bell Helicopter
Textron, Inc.).
FIGURE 15-2
Dimensional definitions for helicopters.
Aircraft
Rotor
Diameter, ft
Overall
Length, ft
Height, ft
Wheelbase, ft
Aerosp 330J
49.5
59.8
16.9
13.2
Wheel
Tread, ft
7.9
Gross
Weight, lb
Maximum
Passengers
16,315
19
Aerosp 332L
51.2
61.4
16.2
17.2
9.8
18,410
24
Bell-212
48.0
47.3
13.0
7.6
8.3
11,200
14
Bell-214ST
52.0
62.2
13.2
8.1
8.3
17,500
18
B-Vertol 107II
50.0
83.3
16.9
24.9
12.9
20,000
25
B-Vertol 234
60.0
99.0
18.7
25.8
10.5
48,500
44
B-Vertol 360
83.7
49.7
19.4
32.7
11.4
36,160
30
Sikorsky S-61N
62.0
73.0
18.9
23.5
14.0
20,500
28
Sikorsky S-64
72.0
88.5
25.4
24.4
19.8
42,000
45
Sikorsky S-76B
44.0
52.5
14.5
16.4
8.0
11,400
12
Westland 30300
42.5
52.1
16.3
17.8
9.3
16,000
19
Sources: International Civil Aviation Organization and Federal Aviation Administration.
TABLE 15-1
Dimensions of Typical Commercial Helicopters
633
634
Special Topics in Airpor t Planning and Design
3. The provision of minimum disturbance from noise and desirable location with respect to adjacent land use
4. The provision of adequate access to surface transportation
and parking
5. The cost to acquire and develop
6. The provision of two approach paths separated by at least 90°
and oriented with respect to prevailing winds
7. The avoidance of traffic conflicts between helicopters and
other air traffic
8. The consideration of turbulence and visibility restrictions
presented by nearby buildings
9. The provision of emergency landing areas along the entire
route for single-engine helicopters
Final selection of a heliport site will usually require a compromise
among these various factors. The most severe problems can be
expected in large, highly developed metropolitan areas. In large
urban areas heliports should be planned on a regional basis. The first
step is to prepare an estimate of the demand for helicopter services
and the origins and destinations of this demand. The second step is to
select a heliport site or sites which can reasonably satisfy the demand
and yet meet the requirements cited above.
The principal market for commercial helicopter transportation has
been in large urban areas between one or more airports and the central
business district. Therefore, it is essential that the downtown heliport
be centrally located near the hotel area and the business district. Likewise adequate provision for helicopters should be made at airports. In
extremely large urban complexes, there may be outlying smaller
centers, and secondary heliports are needed so that the benefits of air
transportation can extend to these centers. A heliport must have good
access to streets, highways, and public transit facilities so that passengers using buses, personal vehicles, or mass transit can easily reach
the facility.
Noise
The noise caused by helicopter operations within or adjacent to builtup urban areas is and will continue to be an extremely important factor in planning for helicopter transport, as it has been with fixed-wing
aircraft. Manufacturers are aware of this problem and continue to
study ways in which noise can be minimized.
A heliport should be located so that the noise generated by helicopters will not cause excessive disturbance to surrounding developments. The noise factor is most critical underneath the flight path on
takeoff and landing. The amount of sound that can be tolerated by the
average person is dependent upon a number of factors, including the
Heliports
overall noise level, its frequency, and its duration, the type of development (residential, industrial, etc.) surrounding the source of the
noise, and the ambient sound level in the area. A greater amount of
noise can be tolerated in industrial areas than in residential areas.
Docks and other waterfront sites offer some of the best possibilities
for heliport location in large, congested urban centers. Approach and
noise problems can usually be overcome by making the use of water
areas for heliport location. The downtown heliport in New York City
is an example of such a facility.
Noise generated by small two- and three-seat helicopters can be
tolerated in business and industrial areas, but the noise generated
by large multiengine helicopters powered by turbine engines can
exceed tolerable levels even in business and industrial areas. It is
well to check with the manufacturers concerning the latest information on the levels of noise generated by the several transport type
helicopters.
To minimize the noise, it is desirable to orient the landing pad so
that landings and takeoffs are made over areas where noise would be
least objectionable. Considerably more latitude can be exercised in
this respect for helicopters than with fixed-wing aircraft.
Protection of Approach and Departure Paths
Zoning is necessary both to control the location of heliport sites for
maximum benefit to the community and to provide safety in helicopter operations by protection of the surrounding airspace. The
dimensions of the approach-departure paths for various types of
heliport operations are discussed below.
Turbulence and Visibility
Another factor which must be considered in the selection of a site for
a heliport is the effect of turbulence over roof surfaces and downdrafts near buildings. This factor is of particular importance for rooftop heliports. If there is doubt in the planner’s mind, the site should
be flight-checked with a helicopter.
Poor visibility can be an important factor to consider for sites on
tall buildings, that is, those of 100 ft or more in height. The cloud deck
seldom reaches the ground, but at higher levels the heliport might
find itself enveloped in fog when the ground is clear.
Physical Characteristics of a Heliport
A heliport is defined as a facility which is intended to be used for
the landing and takeoff of helicopters, and may include space for
helicopter parking, buildings, servicing facilities, and vehicular
parking. The final approach and takeoff (FATO) area is a defined area
over which the final phase of the approach maneuver to a hover or
635
636
Special Topics in Airpor t Planning and Design
a landing is completed and from which the takeoff maneuver is
commenced. The touchdown and liftoff (TLOF) area is a hard surfaced
load bearing area typically located within the final approach and
takeoff area on which a helicopter may touch down or lift off. Functionally, the terminal area requirements for the parking, servicing,
and fueling of helicopters and the processing of passengers and
ground vehicles are no different from the requirements for fixedwing aircraft.
Heliports are usually classified according to use as follows:
Military heliport: Facilities operated by one of the branches of the
armed services. The design criteria are specified by the branch of
the service and usually prohibit nonmilitary uses.
Federal heliport: Facilities operated by a nonmilitary agency or
department of the federal government. They are used to carry
out the functions appropriate to the agency.
Private-use heliport: Facilities which are restricted in use by the
owner. These may be publicly owned but their use is restricted,
as in police or fire department use.
Public-use heliport: Facilities which are open to the general public
and do not require the prior permission of the owner to land. The
extent of the facilities available may limit operations to helicopters
of specified sizes or weights.
Commercial service heliport: Public use and public owned facilities
which are designed for the use of helicopters in commercial passenger or cargo service which enplane 2500 passengers annually
and receive scheduled passenger service with helicopters.
Personal-use heliport: Facilities which are used exclusively by the
owner.
The principal components of a heliport are the final approach
and touchdown area, the touchdown and liftoff area, and, for large
heliports, taxiways, helicopter parking areas, and the terminal building area. The relationships between these components are shown
in Fig. 15-3.
Final Approach and Takeoff Area
The final approach and takeoff area (FATO) is a surface from which
the helicopter can land or take off. The FAA allows the FATO to be
any shape as long as it is enclosed by a square of the dimensions
indicated in Table 15-2. ICAO specifies that the FATO is a circle. Its
size depends primarily on the overall length of the largest helicopter to be accommodated by the heliport. Because of the dust that can
be created by the rotor of a helicopter, it is necessary to prepare the
surface of the landing and takeoff area so that it will be free of dust
Heliports
FIGURE 15-3
Typical heliport layout (Federal Aviation Administration).
(e.g., turf or pavement). It is recommended that paving or stabilizing
the soil of the takeoff and landing area to improve the load carrying
ability of the surface, minimize the erosive effects of rotor downwash,
and to facilitate surface runoff due to rain or snow.
The recommended dimensions of the final approach and takeoff
area are given in Table 15-2. For precision instrument operations the
final approach and takeoff area is 300 ft wide by 1225 ft long and incorporates a final approach reference area (FARA) which is an obstructionfree area 150 ft by 150 ft located at the far end of the final approach and
takeoff area.
637
638
ICAO
Private
FAA
Public Utility
Commercial Transport
Land
Length
1.5Lb
1.5Lb
200 ftb
1.5D h
1.5D + 10%i
Width
1.5L
1.5L
2R
1.5D
1.5D + 10%i
Clearance
1/3R c
1/3R c
30 ft
0.25D i
1.5U
1.0L
1.0Le
1.5U
1/3R g
30 ft
30 ft
l
1.5U
1.5U
l
Hover operations
R + 60 ft
R + 60 ft
2R
Ground operations
R + 40 ft
R + 40 ft
7.5–20 m j
Hover operations
R + 90 ft
R + 90 ft
Ground operations
R + 70 ft
R + 70 ft
2T
2T
Water
Final approach and takeoff area
b
b
d
h
Touchdown and liftoff area
Length and width
Parking area
Clearancef
Minimum width
One way taxiway route width
Parallel taxiway route width
Taxiway pavement width
Air transit route
7R k
0.25D i
a
L is overall length of design helicopter; R is rotor diameter of design helicopter; U is maximum of undercarriage length or width of design helicopter;
D is the overall length or width of the design helicopter, whichever is greater; T is wheel tread of design helicopter.
b
May need to be adjusted for elevation; see AC 150/5390-2B.
c
Minimum of 10 ft for private; minimum of 20 ft for public.
d
100 ft for public owned.
e
Position on major axis of FATO with its center at least 50 ft from end or edge of FATO.
f
Cannot lie under approach or climb path.
g
Minimum of 20 ft.
h
The overall length or width of the design helicopter, whichever is greater; for class 2 or class 3 helicopters on water heliports this is 2D; the FATO
described is circular with this diameter.
i
For VFR; for IFR the clearance should be at least 45 m on each side of the centerline and 60 m beyond the ends.
j
Depending upon the main gear span; separation between parallel taxiways should be 60 m on the side and 90 m on the ends of the final approach and
takeoff area.
k
For daytime operations; 10D for nighttime operations
l
The same as for an aircraft parking area; see Chap. 6.
Sources: Federal Aviation Administration [10] and International Civil Aviation Organization [3].
TABLE 15-2 Geometric Design Standards for Heliportsa
639
640
Special Topics in Airpor t Planning and Design
Touchdown and Liftoff Area
Within the final approach and takeoff area, an area is designated for
the normal everyday landing of helicopters. The TLOF area is usually
defined by a solid border painted on the pavement surface. The recommended dimensions of the touchdown and liftoff area are given in
Table 15-2.
Peripheral Area
A peripheral or clearance area surrounding the final approach and
takeoff area is recommended as an obstruction free safety zone. The
area should be kept free of objects hazardous to the operation of helicopters. The clearance from the edges of the final approach and takeoff area required for this area is also given in Table 15-2.
Effect of Wind
Although helicopters can maneuver in much higher crosswinds than
fixed-wing aircraft, the takeoff and landing area should preferably be
oriented as nearly as possible to permit operation into the wind. At
the present time it appears that the crosswind characteristics of the
helicopter will be such that for a majority of cases a rectangular takeoff and landing area need be oriented in one direction only.
Terminal Area
At heliports where the volume of traffic is relatively small, the loading
and unloading of passengers can be accomplished within the final
approach and takeoff area. As traffic increases, it becomes necessary to
provide additional space for the parking of helicopters and passenger
processing. This is usually accomplished on a helipad which is an area
adjacent to the terminal building for processing passengers. This area
provides for one or more parking spaces for helicopters and is similar
in nature and function to the gate or ramp area provided on the apron
adjacent to airport terminal facilities. Clearances between adjacent
helicopter parking positions are provided so that a separation is provided between the rotor planes of helicopters as shown in Table 15-2.
The helipad is connected to the final approach and takeoff area by
taxiways and taxilanes. Helicopters may traverse taxiways in a hover
or ground mode on single or parallel taxiway routes. The width of
these taxiway routes and the taxilanes adjacent to the helipad are
given in Table 15-2. The taxilane widths are the same as the taxiway
routes in a ground mode of operation.
Approach and Takeoff Climb Path
There is a requirement that heliports have at least one approach and
takeoff climb path which is free of obstructions that should be established on the basis of the direction of prevailing winds and the access
route that has the fewest obstacles in the flight path. As conditions
permit, additional approach and takeoff climb paths should be established to facilitate operations at times when winds are from other
directions. At private use heliports, it is recommended that these
Heliports
paths flare out in the horizontal plane from the final approach and
takeoff area at the rate of 1:20 and slope upward at the rate of 8:1.
These paths terminate when the design helicopter attains a safe en
route altitude. These paths may curve to avoid objects or noise sensitive areas when necessary. The FAA is in the process of developing
design criteria for curved visual approaches and recommends that the
FAR Part 77 specifications be applied until these criteria are developed.
For a commercial service airport it is recommended that at least one
instrument approach and takeoff climb path be established. For public
use heliports the dimensions of the final approach and climb paths correspond to those specified under FAR Part 77 as discussed below.
Obstruction Clearance Requirements
Imaginary obstruction clearance surfaces are established for each
class of heliport in FAR Part 77 [10]. For heliports, the principal surfaces are the approach and departure surfaces, the transitional surfaces, and the heliport protection zone. The heliport protection zone is
the area on the ground below the approach surface from the edge of
the final approach and takeoff area to the point where the approach
surface is 35 ft above the elevation of the final approach and takeoff
area. The horizontal surface required for airports is not necessary for
heliports. The approach surface requirements for visual, nonprecision instrument and precision instrument operations specified by
the FAA are given in Table 15-3. Similar requirement are specified
Types of Approach
Visual
Nonprecision
Precision
Length
4,000
10,000
25,000∗
Inner width
†
500
1,000
Outer width
500
5,000
6,000
Slope
8:1
20:1
34:1
Inner width
†
†
600
Outer width
250
600
1,500
Slope
2:1
4:1
7:1
‡
Transitional
∗
Begins 1225 ft from the far end of the final approach and takeoff area.
Width of final approach and takeoff area.
‡
For a 3° glide slope; 22.7:1 for a 4.5° glide slope; 17:1 for a 6° glide slope; glide
slope can be increased in 0.1° increments with corresponding corrections to
approach slope.
Source: Federal Aviation Administration [10].
†
TABLE 15-3 FAR Part 77 Approach Surface Dimensions for Heliports, ft
641
642
Special Topics in Airpor t Planning and Design
FIGURE 15-4 Obstruction clearance requirements for heliports (Federal
Aviation Administration [10] ).
by ICAO [3]. Precision instrument operations by commercial helicopters are very limited and thus visual or nonprecision instrument
operation criteria will suffice for most heliports. The various FAR
Part 77 surfaces are shown in Fig. 15-4. It should be noted that curvedpath approaches and departures are currently not permitted under
IFR conditions but with the implementation of microwave landing
systems (MLS) this is subject to change. The FAA has developed specifications for the MLS critical areas and siting requirements which
should be consulted if the installation of an MLS is contemplated. The
specifications for IFR are a function of the nature of the navigational
aids and references [10] should be consulted prior to establishing
landing and takeoff paths.
The various dimensions specified by the FAA for a commercial
service heliport are illustrated in Example Problem 15-1.
Example Problem 15-1 Let us design the layout of a commercial service heliport
for operations with a Boeing-Vertol 234 design helicopter. Let us assume that
the helipad or parking apron adjacent to the passenger terminal building will
require space for four helicopters. Let us assume that the heliport elevation is
800 ft above mean sea level. A ground taxiway route is to be provided from the
touchdown and liftoff area to the helipad.
From Table 15-1 the design helicopter has a rotor diameter D of 60 ft, an
overall length L of 99 ft, a height of 18.7 ft, a wheelbase of 25.8 ft, a wheel tread
of 10.5 ft, a maximum gross weight of 48,500 lb, and a maximum capacity
44 passengers.
For a commercial service heliport, from Table 15-2 the final approach and
takeoff area is required to have a minimum length of 200 ft and a minimum width
of 2 times the rotor diameter or 2(60) or 120 ft. An object-free clearance width of at
least 30 ft from the edges of the final approach and takeoff area is also required.
The length and width of the liftoff and touchdown area is equal to the overall
length of the design helicopter or 99 ft. Let us use 100 ft for these dimensions. To
provide for the length of the helicopter and the minimum object-free area distance from the final approach and takeoff area, the minimum length of the taxiway leading to and from the touchdown and liftoff area is 100 + 30 or 130 ft.
Heliports
Parking positions must have a minimum width of 1.5 times the undercarriage length or undercarriage width whichever is greater. The greater of these
two dimensions is the wheelbase and therefore, the required minimum width
of a parking position is 1.5 (25.8) or 39 ft. Let us provide 40 ft. However, since
the rotor diameter of the design helicopter is 60 ft, the minimum width of the
parking position must be 60 ft of which 40 ft will be paved. There must also be
a clearance between the edges of adjacent parking positions 30 ft. This results
in the minimum distance between the centerlines of adjacent parking positions
being 90 ft.
A paved ground taxiway will be provided and this must have a minimum
width of 2 times the wheel tread or 2(10.5) or 21 ft. The ground taxiway route
is also required to have a safety area width of the rotor diameter plus 40 ft or
60 + 40 or 100 ft. Taxiways or taxilanes in the vicinity of the terminal building
must also have this safety area to provide clearances between the building and
parked helicopters. Therefore, the minimum distance from the centerline of the
taxiway or taxilanes is 50 ft.
The layout of the heliport with the corresponding dimensions is shown
in Fig. 15-5.
FIGURE 15-5
Commercial service heliport layout for Example Problem 15-1.
643
644
Special Topics in Airpor t Planning and Design
Marking of Heliports
The primary purpose for marking heliports is to identify the area
clearly as a facility for the use of helicopters. The requirements for
marking heliports are specified by the FAA and the ICAO. Essentially
these requirements consists of painting an equilateral square with an
“H” in the center of the touchdown and liftoff area. For hospital heliports a white cross is also inscribed within the square along with the
letter “H” as shown in Fig. 15-6 for the heliport located at the Alexian
Brothers Medical Center in Dade County, Florida. Marking delineating the edges of the final approach and takeoff area should be broken
white lines whereas on the touchdown and liftoff area the edges
should be delineated by continuous white lines. Taxiway centerlines
are delineated by solid yellow lines and taxi route centerline and
apron edge markings should be solid yellow lines. Taxiway edges
should be marked by a double solid yellow line. A painted yellow
line is also recommended to define the centerline of parking positions
and when these positions vary in the amount of clearance provided a
number enclosed by a circle should be painted on the entrance to the
parking position to indicate the largest helicopter that can be accommodated.
Lighting of Heliports
For operation during hours of darkness various types of lights are
suggested [10]. The amount of lighting depends on the character and
FIGURE 15-6 Heliport located at Alexian Brothers Medical Center in Dade County,
Florida (Howard Needles Tammen & Bergendoff and Alexian Brothers Medical Center ).
Heliports
volume of operations. More lighting is required for scheduled air
carrier operations than for private heliports with occasional use.
The minimum recommendations for private use and public use
heliports consist of lighting of the perimeter of either the final approach
and takeoff area or the touchdown and liftoff area with lights with
yellow lenses uniformly spaced at 25-ft intervals. At public use heliports green lights are used to define the taxiway and taxilane centerlines. For commercial service heliports the touchdown and liftoff area
is delineated by yellow lights located 10 ft from the outside edge. At
such heliports in-pavement green lights are recommended for taxiway and taxilane centerlines. Blue retroreflective markers are also
used at these airports to identify taxiway entrance and exit points and
to define taxiway edges. Perimeter lighting defining the touchdown
and liftoff area of a commercial service heliport is shown in Fig. 15-7.
All objects that penetrate the obstruction clearance surfaces should be
lighted with red colored lights.
Other useful lighting aids are the landing direction lights, visual
glide path indicators, and heliport identification beacons. The landing direction lights are miniature approach lights since they extend
only 75 ft. The color is yellow. Visual glide path indicators are also
recommended for visual operations at commercial service heliports.
The lowest on-course signal should provide a 1° clearance over any
object in the approach path within 10° horizontally on either side of
the approach path centerline. The optimal location is on the extended
runway centerline of the approach path such that it will bring the
FIGURE 15-7 Helipor t lighting configuration (Federal Aviation
Administration [10] ).
645
646
Special Topics in Airpor t Planning and Design
helicopter to between a 3- and 8-ft hover distance over the touchdown and liftoff area. Heliport identification beacons, alternate flashing white-green-yellow lights should be located with one quarter of a
mile from a commercial service heliport.
Elevated Heliports
When ground level sites are not available or are unsuitable, an elevated site may be practical. Elevated heliports may be located on
piers or other structures over water, as well as on buildings. The
dimensions of the touchdown and liftoff area are the same as for
heliports on the ground, but the final approach and takeoff area
can be smaller and there is no need for peripheral areas. When
planning a rooftop heliport, a thorough study should be made
of the air currents caused by the presence of adjacent buildings.
Roof areas make it possible to locate the heliport closer to the center
of business activities in a city, provided the facility is environmentally acceptable. Another advantage is that the land cost is partially
absorbed by the tenancy of the lower floors of the building.
However, it should be realized that of the operations of any size,
space on the floors below the takeoff and landing area may have to
be devoted to uses such as lobby, freight, and baggage handing.
The possible disadvantage of height with respect to visibility was
mentioned earlier. A heliport 100 ft or more above the ground
would require a higher cloud base than a ground heliport to provide
the same operating safety. A downtown commercial heliport would
require, in addition to lobby space, car parking facilities relatively
close by.
Where heliports are built on elevated structures, the strength of
the floor should be greater than the strength of the landing gear of the
helicopter. The loads imposed by helicopters and recommendations
concerning the structural design of elevated structures are discussed
in the next section.
Structural Design of Heliports
Helicopters using facilities on land are usually supported on tubular skids or wheels equipped with rubber tires. Helicopters
equipped with conventional landing gear wheels are normally supported by two main wheels and one tail or nose wheel. For larger
helicopters each main landing gear consists of two wheels. Each
main gear typically supports 40 to 45 percent of the weight of the
helicopter and the tail or nose wheel supports the remainder of the
weight, approximately 10 to 20 percent. If the helicopter is supported by tubular skids, 50 percent of the weight is supported by
each skid.
Heliports
The strength requirements for the touchdown and liftoff area are
determined by considering the static load, dynamic load, and downwash load of the helicopter. Both the static load and the dynamic load
are applied through the landing gear contact area whereas the downwash load is applied over a contact area defined by the diameter of
the rotors. The FAA recommends that for design purposes the touchdown and liftoff area should be capable of supporting 150 percent of
the maximum takeoff weight of the design helicopter.
Heliports at Airports
A large number of helicopters will operate into airports to serve
traffic from the downtown area and surrounding communities.
Accordingly, provisions should be made at an airport for the landing and takeoff of helicopters. The takeoff and landing area should
be located to
1. Provide maximum separation from fixed-wing aircraft traffic
patterns so as to avoid creating a conflict in takeoff and landing operations.
2. Be as close as possible to passenger check-in areas for fixedwing aircraft to avoid long walking distances for passengers.
3. Avoid as much as possible the mixing of taxiing fixed-wing
aircraft and helicopters, since helicopters taxi at relatively
low speeds.
It is recommended that if simultaneous same direction diverging
helicopter and fixed-wing aircraft operations are to be conducted
under visual flight rule conditions, a runway centerline to a final
approach and takeoff area and a touchdown and liftoff area centerline separation of 700 ft be provided. A 2500-ft minimum separation
is required for radar departures under instrument flight rule conditions [10]. Helicopter parking apron areas should meet the same runway clearance standards as those required for fixed-wing aircraft
parking [5].
Alternative locations for heliports at an airport are the roof of the
terminal building, the apron adjacent to the terminal building used
by fixed-wing aircraft, and the area adjacent to the terminal building
separate from the fixed-wing aircraft apron. There are advantages
and disadvantages to all three locations. Normally, a ground-level
site is preferred. The most convenient and least expensive method for
accomplishing this is to reserve a part of the fixed-wing aircraft apron
for the takeoff and landing of helicopters. If this is not convenient, a
special pad for helicopter operations on the aircraft side of the terminal building should be provided.
Figure 15-8 shows the heliport at Miami International Airport.
647
648
Special Topics in Airpor t Planning and Design
FIGURE 15-8 Heliport at Miami International Airport (Howard Needles Tammen and
Bergendoff & Miami International Airport).
References
1. A Canadian STOL Air Transport System—A Major Program, Report No. 11,
Canadian Science Council, Ottawa, Canada, 1970.
2. Aerodrome Design Manual, Part 2: Taxiways, Aprons, and Holding Bays, 2d ed.,
International Civil Aviation Organization, Montreal, Canada, 1983.
3. Aerodromes, Annex 14 to the Convention on International Civil Aviation, Vol. II,
Heliports, International Civil Aviation Organization, Montreal, Canada, 1990.
4. A Guide to STOL Transportation System Planning, The DeHavilland Aircraft of
Canada, Limited, Ottawa, Canada, January 1970.
5. Airport Design, Advisory Circular AC 150/5300-13 Federal Aviation
Administration, Washington, D.C., 1989.
6. Canadian STOL Demonstration Service Montreal STOL Port Master Plan, ST-71-8,
Canadian Air Transportation Administration, Ottawa, Canada, March 1972.
7. Certification and Operations of Scheduled Air Carriers with Helicopters, Part 127,
Federal Aviation Regulations, Federal Aviation Administration, Washington,
D.C., 1974.
8. Guide for the Planning of Small Airports, Roads and Transportation Association
of Canada, Ottawa, Canada, 1980.
9. Helicopter Annual, Helicopter Association International, Alexandria, Va., 1992.
10. Heliport Design, Advisory Circular AC 150/5390-2B, Federal Aviation
Administration, Washington, D.C., September 2004.
11. Objects Affecting Navigable Airspace, Part 77: Federal Aviation Regulations,
Federal Aviation Administration, Washington, D.C., 1989.
12. Planning and Design Criteria for Metropolitan STOL Ports, Advisory Circular AC
150/5300-8, Federal Aviation Administration, Washington, D.C., April 1975.
13. “Planning STOL Facilities,” L. Schaefer, Paper No. 690421, Proceedings, Society
of Automotive Engineers, New York, 1969.
Heliports
14. Provisional Criteria for STOL Port Zoning, Canadian Air Transportation
Administration, Ottawa, Canada, August 1973.
15. Quiet Turbofan STOL Aircraft for Short-Haul Transportation, Contractor Report
Nos. NASA CR 114612 and CR 114613, National Aeronautics and Space
Administration, Washington, D.C., June 1973.
16. Rotorcraft Master Plan, Federal Aviation Administration, Washington, D.C.,
November 1990.
17. STOL Aircraft Future Trends, Transport Aircraft Council, Aerospace Industries
Association of America, Inc., Washington, D.C., May 1971.
18. STOL Port Manual, 1st ed., Doc 9150-AN/899, with Amendment 1, International
Civil Aviation Organization, Montreal, Canada, 1988.
19. STOL-VTOL Air Transportation Systems, C. Hintz, Jr., Civil Aeronautics Board,
Washington, D.C., 1970.
20. Studies in Short Haul Air Transportation—Effects of Design Runway Length,
Community Acceptance, Impact on Return on Investment and Fuel Cost Increases,
R. S. Shevell and D. W. Jones, Jr., Stanford University, National Aeronautics and
Space Administration, Ames Research Center, Moffett Field, Calif., July 1973.
21. Study of Aircraft in Intraurban Transportation Systems, San Francisco Bay
Area, Boeing Company, Contractor Report No. NASA CR-114347, National
Aeronautics and Space Administration, Ames Research Center, Moffett Field,
Calif., 1970.
22. Study of Quiet Turbofan STOL Aircraft for Short-Haul Transportation, McDonnellDouglas Corporation Report No. MDC-J4371, for National Aeronautics and
Space Administration, Moffett Field, Calif., June 1973.
23. Study of Short-Haul Aircraft Operating Economies, Contractor Report No. CR137685, Ames Research Center, National Aeronautics and Space Administration,
Moffett Field, Calif., September 1975.
24. United States Standard for Terminal Instrument Procedures (TERPS), FAA Order
8260.3B, with Changes 1 through 12, Federal Aviation Administration,
Washington, D.C., 1992.
25. Vertiports, Advisory Circular AC 150/5390-3, Federal Aviation Administration,
Washington, D.C., 1991.
26. “V/STOL Aircraft: The Future Role in Urban Transportation as a Pickup and
Distribution System,” R. H. Miller, Proceedings of Symposium on Transportation
and the Prospects for Improved Efficiency, National Academy of Engineering,
Washington, D.C., October 12, 1972.
649
This page intentionally left blank
Index
Note: Page numbers followed by “f ” or “t” indicate figures or tables, respectively.
A
AAAE. See American Association of Airport
Executives
above mean sea level (AMSL), 101
above the ground (AGL), 100
absolute zero, 71
accelerate-stop distance (DAS), 85
accelerate-stop distance available (ASDA),
88
access interface
ground access system of, 384
of passenger terminal system, 384
system, 401
access modes/modal splits, 393
ACI. See Airports Council International
ACs. See Advisory Circulars
ADAP. See Airport Development Aid
Program
ADF. See arrival delay factor; automatic
direction finder
ADG. See airplane design group
ADI. See arrival delay index
ADOs. See Airports District Offices
ADS. See automated dependent
surveillance
ADS-A (address), 126
ADS-B (broadcast), 126–127
ADSIM. See airport delay simulation model
Advisory Circulars (ACs), 41
aerodrome reference code, 175–176,
176t
“Aerodromes,” 45
Aerospace Industries Association
of America (AIA), 45
aggregate forecasting, 151–152, 162
AGL. See above the ground
AIA. See Aerospace Industries Association
of America
aiming points, 320–321
AIP. See Airport Improvement Program
air cargo, 8–10
six regions for, 9
world wide, 9f
worldwide distribution of, 10t
air carriers, 32–33, 603f
commercial, 7
commuter, 7, 8t
international, 7
passenger, 7, 60t
regional, 7, 8t
air charter services, 7
Air Commerce Act of 1926, 17–18, 96
air density, 70
Air Line Pilots Association, International
(ALPA), 45
Air Mail Act of 1925, 17
air navigation, obstructions to,
216–218, 220–221
air operations area (AOA), 469, 470
air pressure, 70
air quality, 576–577, 578f
air route surveillance radar (ARSR), 98, 118,
128f
air route traffic control centers (ARTCC),
97–98
Air Services Australia, 96
air taxi operators, 7
air temperature, 70
air traffic, 135, 511t
air traffic control
growing need for, 25
minimum separation rules used by,
504
radar-based surveillance of, 118,
127–129
voice communication and, 127
Air Traffic Control System Command
Center (ATCSCC), 97
air traffic management
history of, 96
modernization of, 127–130
organizational hierarchy in, 97–100
rules of, 100–101
understanding of, 95
air traffic separation rules, 110–114,
493, 494t
Air Transport Association of America (ATA),
45
651
652
Index
air transportation
civil/passenger traffic, 8f
commercial, 3
forecast variables, 163t
government agencies and, 18
international, 7–8
regulation of, 18–19
sociological changes from, 4
in United States, 5
AIR-21, 34
Airborne Instruments Laboratory, 507
aircraft, 176
airfield separation criteria by, 212t, 213,
214t, 215t
airport classification by, 174–177
airport demand of, 529–531, 529f
annual departures and, 269t
apron circulation of, 457
arrival distribution of, 445t, 446f
arrival v. time of, 530f
average delay of, 522f
A-weighted sound level of, 583f
centerline curve tracking of, 247
crab angle and, 74
critical, 174, 194
delay, 535f
dimensional standards of, 57–59, 58f
dry runway exits and, 242t
efficiency focus on, 57
engine categories of, 63
flight altitudes of, 111
fuel consumption of, 64–65, 67
fueling of, 458–460
general aviation, 55t–56t
GPS systems on, 125f
grounding facilities of, 460
height information in, 294–295
horizontal separation of, 113t
landing critical point of, 122–123
landing fees of, 567
landing operations of, 293
landing process of, 240–241
large, 176
light, 286–287, 286f
loading bridge, 458f
minimum longitudinal separation of, 112
minimum time separation decreasing of,
501–502, 504–505
minimum time separation increasing of,
499–501, 505–507
minimum time separation of, 500f, 503f
new technologies in, 49–50
noise influence of, 592–593
noise monitoring systems on, 602–604
noise/performance data of, 601
nose wheel tracking of, 244–246
occupancy time exiting of, 245t
100 percent of fleet, 196t
operational data of, 601
parking type, 455–457, 455f
pollutants produced by, 577
pollution, 579
runway capacity/arriving, 498
runway demand of, 523t
runway length and, 198–201
servicing activity time schedule of, 443f
aircraft (Cont.):
75 percent of fleet, 195t
size/speed greater of, 135
small, 176, 192–193
sound exposure levels of, 588–589
specifications, 49, 50
speed of, 75–77
stand taxilane centerline, 233
terminal aprons/ramps minimum
clearance and, 252t
track/heading/crosswind influencing,
74–75
turning radius of, 58–59, 59f
type/operating characteristics of, 510t
United States registration of, 10–11
weight, 61–63
wide-bodied, 301–302
aircraft approach category, 75, 174, 175t
Aircraft Mix Index, 517t
Aircraft Owners and Pilots Association
(AOPA), 45, 481
aircraft performance, 75–90
air density influencing, 70
aircraft speed and, 75–77
atmospheric conditions influencing, 69–75
declared distances and, 82–89
field elevation influence on, 80
payload/range and, 77–79
runway gradient influencing, 80–81
runway length and, 79–80
runway surface conditions influencing,
81–82
stalling and, 76
surface wind influencing, 80
V-speeds in, 77
wing tip vortices influencing, 89–90, 90f
airfield
capacity, 487–489
capacity/delay planning for, 485–486
costs, 566–567
drain inlet capacities, 366t–367t, 368t–369t
drainage system with ponding and, 350–
358
marking/signage, 291–292, 329, 341f
pavement, 257, 258f
separation criteria, 212t, 213, 214t, 215t
underground storm drains, 366t–367t
“Airfield Pavement Design and Evaluation,”
257, 285
Airline Deregulation Act of 1978, 31–32
airlines
activities planning, 415
deregulation, 32–33
objectives, 392
schedule, 444t
simulated schedule of, 449t
air-mail route, 17
airplane design group (ADG), 174, 175t
airport(s). See also commercial service
airports; runway(s)
activity, 150
air quality study process of, 578f
annual traffic of, 165
assistance programs, 28
baggage claim facilities in, 411–414, 411f
beacon, 293
Index
airport(s) (Cont.):
CAA recommendations for, 19–21
capital development costs of, 565t
categories of, 551–552
civil aviation, 11–17
Class B airspace around these,
102–104, 103f
classification, 174–177
connecting, 396
controlled, 104
data/databases/studies of, 168
demand forecast of, 155t
design objectives for, 392
drainage design details for, 351f
drainage layout of, 364f
drainage systems at, 619–620
federal aid programs for, 545–547
financing capital improvements of, 146
fiscal policies of, 563
further CAA recommendations for,
21–23
future security of, 481–482
general aviation, 11, 481
heliports at, 647
hourly aircraft demand at, 529–531, 529f
hub classification of, 13t
improvements financing of, 557–558
international, 300
management objectives, 392
navigational chart of, 110f
noise, 579
noise problem from, 598–600
noise-based use restrictions of, 607–609
operations/services of, 416
performance/demand patterns and,
149–150
PMS used at, 287–288
primary, 11
primary service, 552
privatization of, 561–562
project plan, 141–142, 623–624
public, 21–22, 30
public ownership of, 543
reference code, 174–175
reference point, 221
reliever, 12–13
runway capacity studies of, 241
secure area of, 470, 471f
security history of, 468–470
site selection, 137–138
state role in, 36–37
surface runoff of, 347
survey, 21
terminal buildings costs, 621t–622t
terminal projects, 439–441
transport, 177
utility, 176–177
vulnerability assessment of,
477–481, 478f
world’s busiest, 14t–16t
Airport and Airway Development Act of
1970, 27–30, 547, 549
Airport and Airway Improvement Act of
1982, 33, 143, 553
Airport and Airway Revenue Act of 1970,
28, 548
Airport and Airway Trust Fund, 28,
554t–555t
airport annual enplanement (ENP), 160
airport delay simulation model (ADSIM),
537
airport design standards
concepts for, 426f
FAA guidelines for, 173–174
airport development
bond sales for, 23–24
capital costs of, 563, 565–566
environmental study requirements in,
576t
organizations and, 37–46
state sharing in, 557–558
Airport Development Aid Program (ADAP),
547–556, 548, 551
Airport Improvement Program (AIP), 33,
551–552, 553
Airport Layout Plan (ALP), 140
airport master plan, 138–140,
164–168
flowchart for, 139f
future development guidelines of,
138–139
organization of, 139–140
airport movement area safety system
(AMASS), 124
Airport Noise and Capacity Act of 1990, 612
airport operations
early days of, 133–134
major components of, 133, 134f
mathematical models of, 487
obstructions to, 134–135
in terminal planning process, 416
airport planning/design, 41–42. See also
airport master plan; terminal planning
process
air transportation forecast variables in,
163t
aircraft dimensions important to, 57–59
aircraft specifications and, 50
airfield capacity in, 487–489
community development and, 618
continuous planning process in, 146–147
displacement/relocation in, 617
ecological factors in, 619–620
energy consumption and, 624
engineering/economic factors in, 620–624
forecasting and, 166t–167t
future demand forecast items and,
149–150
natural beauty/history impact and,
617–618
runway end siting requirements in,
223–227, 224t–225t, 226t, 228t
social factors involved in, 616–618
studies performed for, 135–146
Airport Security Program (ASP),
470–472
airport surface detection equipment (ASDE),
124
airport system plan, 135–137
elements of, 136–137
forecasting requirements for, 164
objectives of, 136
653
654
Index
airport traffic control tower (ATCT),
99, 99f
Airports Council International (ACI), 45
Airports District Offices (ADOs), 39, 550
airside building concourse level, 391f
airspace
lateral separation in, 113–114
longitudinal separation in,
111–113
uncontrolled, 106
United States classes of, 101–106, 101f,
103f, 105f
vertical separation in, 111
airspeed, 73, 75
Airway Safety and Capacity Expansion Act
of 1990, 33
airways, 106–110
area navigation in, 108–110
colored, 107
jet routes and, 108
navigational chart of, 110f
victor, 106, 108
Airways Modernization Act of 1957, 26
Airways Modernization Board, 25
Alexian Brothers Medical Center, 644f
alignment guidance, 294
ALP. See Airport Layout Plan
ALPA. See Air Line Pilots Association,
International
ALS. See approach lighting systems
ALS with sequenced flashers (MALS), 298
ALS with sequenced flashing lights
(ALSF-2), 297–298
ALS with sequential flashers (MALSF),
298
ALSF-2. See ALS with sequenced flashing
lights
altitudes, higher, 60
AMASS. See airport movement area safety
system
ambient temperature, 72
American Association of Airport Executives
(AAAE), 45
AMSL. See above mean sea level
analysis models, 427
analytical queuing models, 428–438
angled nose-in parking, 455–456
angled nose-out parking, 456
annual delay, 536
annual demand, 535f
annual departures, 269–270, 269t
annual service volume
annual demand/aircraft delay
relationship with, 535f
average delay and, 536
simulation models of, 537–538
technique application for, 532–538
AOA. See air operations area
AOPA. See Aircraft Owners and Pilots
Association
approach
heliports surface dimensions and, 641t
procedure, 123f
speed, 295
surface, 218
threshold lighting in, 303
approach lighting systems (ALS), 123,
296–301
Calvert, 296–297, 297f
CAT II-III, 297f
configurations of, 296–301, 299f, 300f
high intensity, 298
medium intensity, 298
apron gate system, 442–461
aircraft circulation in, 457
aircraft parking type in, 455–457, 455f
apron lighting/marking in, 460–461
electrical power in, 460
gate position painted guidelines in, 461f
gate size in, 453
layout of, 456–457
nose-in parking in, 455–456
number of gates in, 442–448
parking envelope dimensions in,
454
passenger-to-aircraft conveyance in,
457–458
ramp charts in, 448–453, 451t, 452t
simulated airline schedule in, 449t
utility requirements in, 458–461
aprons, 250–254. See also apron gate system;
terminal aprons/ramps
aircraft circulation on, 457
holding, 250–252
inlets and, 369
lighting/marking, 460–461
terminal, 252–254
area navigation (RNAV), 108–110
arrival delay factor (ADF), 521
arrival delay index (ADI), 520, 521f
arrivals
aircraft distribution, 445t, 446f
capacity, 499
exit locations and, 243, 515–516
position error/runway capacity and,
506
threshold/exits, 245t
ARSR. See air route surveillance radar
ARTCC. See air route traffic control centers
ARTS. See Automated Terminal Radar
Systems
ASDA. See accelerate-stop distance available
ASDE. See airport surface detection
equipment
ASP. See Airport Security Program
ATA. See Air Transport Association of
America
ATCSCC. See Air Traffic Control System
Command Center
ATCT. See airport traffic control tower
atmospheric conditions
aircraft performance influenced by,
69–75
runway length and, 79
wind speed/direction and, 73–75
automated dependent surveillance (ADS),
126
Automated Terminal Radar Systems (ARTS),
603
automatic direction finder (ADF),
114, 115f
average delay, 536
Index
aviation. See also civil aviation
demand/capacity analysis of, 140
federal government’s relationship with,
24–25
future forecasting in, 168–169
general, 3, 10–11, 11f
organizations involved in, 37–46
professional organizations involved in,
45–46
short-term forecasting in, 152, 169
state role in, 36–37
Aviation and Transportation Security Act,
34–35, 470, 472
Aviation Noise Abatement Policy, 575
Aviation Safety and Capacity Act of 1990,
33–34
Aviation Safety and Capacity Expansion Act
of 1990, 556
Aviation Safety and Noise Abatement Act of
1979, 29–30, 548
Aviation System Capacity Plan, 38
A-weighted sound level, 581–582, 582f, 583f
B
baggage claim facilities, 411–414, 411f
linear claim footage of, 412f
passenger delay at, 431
total area estimating of, 413f
baggage screening, 474–476
EDS equipment for, 476f
in-line, 475f
TSA mandates for, 475
balance field concept, 84f, 88
barometric pressure, 72
base course, 258, 271–272
base drainage, 376
belly cargo, 9
bituminous materials, 258
bituminous overlay, 283
blast pad, 202
blast pad markings, 322–323, 323f
Boeing 737-900
general airplane characteristics of, 199f
landing runway length for, 200f
takeoff runway length for, 201f
Boeing 767-200, 253
bonds, 23–24, 558–560
BOT. See build, operate and transfer
boundary lights, 303
buffer time, 503
build, operate, and transfer (BOT), 562
building space requirements, 417t
Bureau of Air Commerce, 96
bypass ratio, 67
C
CAA. See Civil Aeronautics Administration
CAAA. See Commuter Airline Association
of America
CAB. See Civil Aeronautics Board
California Bearing Ratio. See CBR method;
CBR test; field CBR value
Calvert, E. S., 296
Calvert system, 296–297, 297f
capacity, 484. See also discharge capacity;
runway capacity; ultimate capacity
airfield planning for, 485–486
analysis approaches to, 486–489
for arrivals, 499
delay/cumulative demand and, 531t
delay/demand and, 488f
demand analysis with, 140
different definitions of, 488
gate, 538–541
gate/analytical models for, 539–541
of intersecting runways, 517
of mixed operations, 509
mixed operation’s hourly, 513–514
runway (IFR), 519f
runway (VFR), 518f
runway studies of, 241
runway system departure only, 512–513
of runway systems, 517
runway system’s hourly, 514–519
capital costs, 563, 565–566
capital development costs, 565t
capital improvements, 146
Castro, Fidel, 469
CAT II-III, 297f
CBR method, 272, 273f
CBR test, 263
CDF. See cumulative damage factor
CDFU. See cumulative damage factor used
centerline curve tracking, 247
centerline intersections, 241–242
centerline markings, 320, 323–325
centerline spacing, 313t
centralized passenger processing, 416–417
CFCs. See customer facility charges
charts, for runway capacity, 516
check-in counter configurations, 406f
check-in facilities, 399f, 405–408
chemical stabilization, 268
Civil Aeronautics Act of 1938, 18–21
Civil Aeronautics Administration (CAA),
19–23
Civil Aeronautics Authority, 19
Civil Aeronautics Board (CAB), 31–32
civil aviation
Air Commerce Act of 1926 and, 17–18, 96
Airline Deregulation Act of 1978 and,
31–32
airline deregulation’s impact in,
32–33
Airport/Airway Development Act of 1970
and, 27–30
airports, 11–17
Aviation Safety and Capacity Act of 1990
and, 33–34
Civil Aeronautics Act of 1938 and, 18–21
commercial service in, 3
DOT creation and, 26–27
FAA regulations for, 39–42
Federal Airport Act of 1946 and, 21–24
Federal Aviation Act of 1958 and, 24–26
legislative actions influence on, 17–36
state agencies involved in, 43–44
three sectors of, 4
trade organizations involved in, 45–46
655
656
Index
Civil Works Administration (CWA), 544
CL. See clearway
class A airspace, 101–102, 101f
class B airspace, 101f, 102–104, 103f
class C airspace, 101f, 104, 105f
class D airspace, 101f, 104–105, 105f
class E airspace, 101f, 105–106
class G airspace, 101f, 106
clearway (CL), 83
climb-out speed, 630
Clinton, Bill, 124
closed markings, 328–329
CNEL. See community noise equivalent
level
CNR. See composite noise rating
coarse-grained soils, 259–260
coastal zones, 619–620
cockpit cutoff angle, 294
coefficient of roughness, 376t
coefficient of runoff, 348–349, 349t
colored airways, 107
combined concepts, in terminal planning
process, 419–422, 420f
commercial air carriers, 7
commercial air transportation industry, 3
commercial service aircraft, 51t–54t
commercial service airports, 3, 4–6, 11, 552
air cargo in, 8–10
baggage screening in, 474–476
employee identification in, 476–477
international air transportation in, 7–8
passenger air carriers in, 7
passenger screening at, 473–474, 473f, 474f
perimeter security at, 477
security at, 472–477
commercial service heliports, 642–643, 643f
common use self-service kiosks (CUSS),
408
common-use gates, 448, 452f
community annoyance, 595–596, 595f
community development, 618
community noise equivalent level (CNEL),
591–592
community objectives, 392
commuter air carriers, 7, 8t
Commuter Airline Association of America
(CAAA), 46
compensatory cost method, 565, 569
composite noise rating (CNR), 579, 592
compound curves, 234–235
concept development, 399, 400, 416–417
concession area costs, 564
conical surface, 218
connecting airport, 396
constrained forecasting, 165
construction
costs, 620
environmental impact of, 615
joints, 278
Continuing Appropriations Act of 1982, 33
continuous planning process, 146–147
continuously reinforced concrete pavements
(CRCP), 279–282
contraction joints, 277–278
control tower, visibility requirements of,
254–255
controlled access gates, 477
controlled airports, 104
Controller Pilot Data Link Communicators
(CPDLC), 98
conversations, sound levels of, 593f, 594
Corps of Engineers, 358–359, 360–365
corridors, 410
CPDLC. See Controller Pilot Data Link
Communicators
CPM. See critical path model
crab angle, 74
CRCP. See continuously reinforced concrete
pavements
criminal behavior, 468
critical aircraft, 174, 194
critical engine-failure speed/decision speed,
85
critical path model (CPM), 428
crosswinds, 73, 74–75, 74f, 80, 185–186
cumulative damage factor (CDF), 270
cumulative damage factor used (CDFU),
285, 285f
cumulative damage failure method, 270
cumulative demand, 531t
cumulative probability distribution, 445
Curtis, Edward P., 25
curvature dimensional standards, 239t
curved path, landing gear, 246f
curves
design parameters, 248–249
entrance, 236f
intersection design, 244–249
overland flow, 363f
sections of, 311f
standard supply, 360, 361f, 362f
CUSS. See common use self-service kiosks
customer facility charges (CFCs), 560
CWA. See Civil Works Administration
D
DAS. See accelerate-stop distance
day-night average sound level (DNL),
587–590, 595f, 606
Daytona Beach International Airport, 104,
105f
DCLA. See development of civil landing
areas
DDF. See departure delay factor
DDI. See departure delay index
decentralized passenger processing, 416–417
decibel scale, 580
declared distances, 82–89, 84f
defense landing area (DLA), 544
delay, 484, 535f
aircraft’s average, 522f
airfield planning for, 485–486
analysis approaches to, 486–489
annual, 536
average, 536
capacity/demand and, 488f
cumulative demand minus capacity with,
531t
graphical methods approximating,
525–531
hourly tabulation of, 526t–527t
Index
delay (Cont.):
mathematical formulation of, 490–492
passenger, 431
in passenger processing systems, 437t
runway system computation of, 520–531
saturated conditions/overload period
and, 525f
demand
of aircraft, 529–531, 529f
annual, 535f
capacity analysis, 140
cumulative, 531t
delay/capacity and, 531t
levels, 484
passenger component, 394
of runway, 523t
terminal, 393
terminal parameters of, 393
demand profile factor (DPF), 522
density altitude, 72
Department of Homeland Security, 470
Department of Transportation (DOT), 26–27,
486
departure delay factor (DDF), 521
departure delay index (DDI), 520, 521f
departures. See also annual departures
annual, 269–270
flight tracks, 603f
heliport paths of, 635
lounges for, 409, 410f
model for, 507
noise abatement procedures and, 607
obstacle identification surfaces, 226f
runway system capacity of,
512–513
separation, 113t
depth of cover, pipes, 375t
design development, 387–393, 399,
441–442
design objectives, for airports, 392
design-day schedule, 443–448, 444t
destination signs, 332, 335, 335f, 338
deterministic queuing model, 525, 528f
development of civil landing areas (DCLA),
544
development plan, O’Hare International
airport, 141f
diesel fuel, 63
dimensional standards, of aircraft,
57–59, 58f
direction signs, 332, 334–335, 334f, 338
disaggregate forecasting, 151–152
discharge capacity, 356–358, 363f
displaced threshold markings,
321–322, 322f
displacement, 617
distance measuring equipment (DME), 115–
117
distance remaining signs, 330–331, 330f, 331f
DLA. See defense landing area
DME. See distance measuring equipment
DNL. See day-night average sound level
domestic passenger traffic, 5f
DOT. See Department of Transportation
dowels, 279
downwind bar, 301
DPF. See demand profile factor
drain inlet capacities, 365
airfield, 366t–367t, 368t–369t
maximum surface storage v., 370f, 371f
drainage systems
airfield with ponding and, 350–358
airport design details for, 351f
airport layout of, 364f
at airports, 619–620
base, 376
design data of, 355t
intercepting, 376
pavement sections and, 372f
pipe types for, 377–378
ponding layout and, 356f
purpose of, 343
rainfall intensity and, 344–347
storm severity and, 343–344
subsurface/grade, 376, 377f, 379
surface drainage and, 368–376
surface runoff computation/no ponding
and, 360–365
dry runway exits, 242t
dual-tandem landing gear, 59
dual-wheel landing gear, 59
dwell times, 401
E
E value, 266
ecological factors, in airport planning,
619–620
econometric modeling, 153, 158–162
economic benefits, 624
economic factors, in airport planning,
620–624
economic/financial feasibility, 145–146
edge markings, 323–325, 327f
EDS. See explosive detection system
effective perceived noise level (EPNL),
590–591
efficiency, of aircraft, 57
Eisenhower, Dwight D., 25
electrical power, 460
elevation
field, 80
of heliports, 646
runway length and, 198
small aircraft /temperature and, 193f, 194f
EMAS. See engineered material arresting
systems
empennage, 57
employee identification, 476–477
endangered species, 619
Endangered Species Act of 1973, 619
end-around taxiways, 249–250, 250f
ending signs, 336–337
energy average sound level (LEQ),
585
energy consumption, 624
engineered material arresting systems
(EMAS), 85
engineering factors, in airport planning,
620–624
engine-failure, 85–86
engines, 63–69
657
658
Index
enhanced markings, taxiways/taxilanes,
328–340, 329f
ENP. See airport annual enplanement
enplanement data, 155t
entitlement funds, 548
entrance curves, 236f
entry gates
aircraft separation, 500f
arrival threshold, 501
entryways, 404–405
environment. See also noise; pollution
conditions, 79–80
construction impacts on, 615
impact overview on, 140
noise problem to, 143–144
policy considerations related to, 574–576
public concern for, 29–30
sound levels found in, 582f
study of, 576t
waste/pollution in, 144
Environment Data and Information Service,
186
environmental impact assessment, 143–145
environmental impact statement,
29–30, 144–145, 575
Environmental Policy Act of 1969, 143
Environmental Protection Agency (EPA), 37,
42–43
EPA. See Environmental Protection Agency
EPNL. See effective perceived noise level
equivalent steady sound level (QL), 585–587
Erlang distribution, 431
error-free interarrival spacing,
496f, 500f
error-free matrix, 498
estimating runway length, 191–201
Eurocontrol, 96
excise taxes, 28
exclusive area, 472
exclusive-use gates, 448, 450, 451f
exits. See also taxiway exit
arrival threshold, 245t
dry runway, 242t
locations, 243, 515–516
range, 243t
explanatory variable sensitivity,
159–160
explosive detection system (EDS),
475, 476f
F
FAA. See Federal Aviation Administration
FAA Reauthorization Act of 2009,
35–36
FAARFIELD software, 270, 273–275, 274f,
277f
light aircraft pavements and,
286–287, 286f
pavement overlays considered in,
283–284
rigid pavement bases and, 277f, 285
facility classification, 394–396
FARA. See final approach reference area
farm tile, 378
FARs. See Federal Aviation Regulations
FATO. See final approach and takeoff
FBOs. See fixed-base operators
federal agencies, 37
federal aid programs, 545–547
Federal Airline Deregulation Act, 5–6
Federal Airport Act of 1946, 21–24, 545–546,
548
Federal Aviation Act of 1958, 24–26, 27
Federal Aviation Administration (FAA), 12,
27, 37–42
airfield pavement guidance of, 257, 258f
airport design guidelines from,
173–174
econometric models used by, 162
functions of, 38–39
mission of, 96
organizational chart of, 40f
pavement design methods of,
268–270
regions of, 41f
runway length estimating procedures of,
191–192
runway signing conventions of,
337–338
taxiway guidance sign system
recommendations from,
336–337
Federal Aviation Regulations (FARs), 39–42,
82
Part 36, 609–610, 610f, 611f
Part 77 of, 216–221, 219f, 641
Part 91, 611–612
Part 107, 469
Part 150, 612
Part 161, 614–615
Federal Emergency Relief Administration
(FERA), 544
federal funding programs, 544–557
federal government. See also government
agencies; state government
air carriers applying to, 32–33
aviation’s relationship with, 24–25
integrated airport system planning and,
552–553
federal-aid program, 22–23
FERA. See Federal Emergency Relief
Administration
ferry range, 78
field CBR value, 261–263
field elevation, 80
field length (FL), 85, 87
fillet design geometry, 247f, 248
filter material, 378–379, 380f
final approach, of heliports, 636–637,
640–641
final approach and takeoff (FATO), 635
final approach reference area (FARA), 637
financial planning, 562–570, 571
financing, of airport improvements,
557–558
fine grain soils, 261
finite element theory, 276–277
fiscal policies, 563
fiscal requirements, 624
fixed-base operators (FBOs), 472
Index
FL. See field length
fleet percentage, 197f
flexible overlay, 283
flexible pavement, 258
base course of, 271–272
CBR method used in, 272, 273f
designing, 271–275
FAARFIELD software and, 274f
pipe coverage and, 373t–374t
subbase course of, 272
flight
altitudes assigned, 111
following, 100–101
gate occupancy duration, 447f
hours, 11f
interface, 386–387
late arriving/canceled, 486f
nighttime, 608
schedule frequency distribution,
445
temporary restrictions on, 106
tracks, 603f, 607
visual rules for, 180–181
flight service stations (FSS), 100
flood hazards, 620
floodlighting, 303, 460
flow-through bypass holding pad, 251–252,
251f
flush lights, 460
forecasting
aggregate, 151–152, 162
air transportation variables in, 163t
airport planning/growth,
166t–167t
airport system plans and, 164
annual airport traffic, 165
constrained, 165
disaggregate, 151–152
econometric modeling, 158–162
explanatory variable sensitivity in,
159–160
four types of, 152
future aviation, 168–169
judgmental, 153–154
levels of, 151–152
market share, 153, 156–158
methods of, 152–162
redundancy in, 161
requirements/applications in,
162–168
short-/medium-/long-term, 152, 169
time series method of, 154–156
unconstrained, 165
Fort Lauderdale-Hollywood International
Airport, 439, 441f
4D RNAV, 109
foyers, 404–405
frost design soil classification, 268t
frost influence, 266–267
FS. See full-strength pavement
FSS. See flight service stations
fuel
for aircraft, 458–460
farm, 459
prices/jet, 69f
trucks, 458
fuel consumption, 64–65, 67
in gallons per seat-mile, 68f
of jet aircraft, 68t
full-strength pavement (FS), 82, 85
fuselage, 57
future activity, 162
future demand patterns, 149–150, 155t
future development guidelines,
138–139
G
gallons per seat-mile, 68f
GAMA. See General Aviation Manufacturers
Association
GARBs. See general airport revenue bonds
gate position painted guidelines,
461f
gates
arrivals concept, 419, 421f
capacity, 538–541
capacity analytical models for,
539–541
common-use, 448, 452f
controlled access, 477
exclusive-use, 448, 450, 451f
number of, 442–448
occupancy distribution, 445
occupancy time, 442
restricted use of, 540
shared use of, 452f
simulation, 447t
sizes, 453
use strategy, 443, 539
wide-bodied, 448
general airport revenue bonds (GARBs),
559
general aviation, 3, 10–11, 11f
general aviation aircraft, 55t–56t
general aviation airports, 11, 481
General Aviation Manufacturers Association
(GAMA), 45
general obligation bonds, 558–559
Geneva Intercontinental Airport, 387,
407, 420f
geometric design standards, 638t–639t
glide slope facility, 122, 294f
global positioning systems (GPS), 109,
124–126, 125f
global regions, 9
governing bodies, of ICAO, 44–45
government agencies, 18
GPS. See global positioning systems
gradient standards
aircraft performance and, 80–81
runway surface, 209t, 211t
of taxiways/taxilanes, 230t, 232t
Graham, Jack, 468
granular material, 378–379
graphical methods, delay, 525–531
gravity models, 159
Greater Pittsburgh International Airport,
385f, 388f–390f, 414f, 602f
gross terminal area space requirements,
396, 397f
ground access system, 384, 385f
659
660
Index
ground radar, 124
ground-based systems, 114–124
grounding facilities, aircraft, 460
groundspeed, 73
guidance sign system, 331
guidance signs, 338–340, 338f
H
HAI. See Helicopter Association
International
Hartsfield-Jackson Atlanta International
Airport, 99f
heading, 74–75
headwind, 73
hearing loss, from noise, 596–597
height information, 294–295
Helicopter Association International
(HAI), 46
helicopters
characteristics of, 630–631
commercial dimensions of, 633t
dimensions of, 632f
nature of, 629–630
noise caused by, 634–635
single/twin engine, 631
helideck, 629
helipad, 629, 640
heliports, 629–647, 648f
at airports, 647
at Alexian Brothers Medical Center,
644f
approach surface dimensions of,
641t
approach/departure paths of, 635
commercial service layout of,
642–643, 643f
elevated, 646
final approach of, 636–637, 640–641
geometric design standards of,
638t–639t
layout of, 637f
lighting of, 644–646, 645f
marking of, 644
obstruction clearance requirements of,
641–643, 642f
peripheral area of, 640
physical characteristics of, 635–636
port authority, 632f
protection zone of, 641
site selection factors of, 631–634
structural design of, 646–647
takeoff area of, 636–637, 640–641
terminal area of, 640
helistop, 629
hertz, 581
high-speed exit taxiways, 237f
Highway Capacity Manual, 402
historical places, 617–618
hold markings, taxiways/taxilanes,
325–326
hold short markings, 327f
holding aprons, 250–252
holding line/runway separation criteria,
215t
holding pads, 251–252, 251f
holding position markings, 326, 339t
horizontal distribution concepts,
417–422, 418f
horizontal segment, 295
horizontal separation, of aircraft, 113t
horizontal surface, 218
hourly noise level, 587
hub and spoke, 12
hub classifications, 12, 13t
human health, 597
hydrant system, 459
hydroplaning, formula for, 81
I
IAS. See indicated airspeed
IATA. See International Air Transport
Association
ICAN. See International Commission for Air
Navigation
ICAO. See International Civil Aviation
Organization
ice lenses, 267
ice segregation, 266, 267f
identification, site, 137
IFR. See instrument flight rules
ILS. See instrument landing system
IM. See inner marker
imaginary surfaces, 218–221, 219f
IMC. See instrument meteorological
conditions
indicated airspeed (IAS), 75
infiltration rate, 359–360
information signs, 336, 338
inlet time, 347, 348f, 352t–354t
inlets, 369
in-line baggage screening, 475f
INM. See integrated noise model
inner approach obstacle-free zone,
203
inner marker (IM), 120
inner transitional obstacle-free zone,
203
instrument flight rules (IFR), 101,
180–181, 519f
instrument landing system (ILS),
118–123
approach procedure with, 123f
capabilities, 122t
configuration of, 120–121, 121f
RVR equipment with, 122
instrument meteorological conditions (IMC),
186
integrated airport system planning,
552–553
integrated noise model (INM), 600–602
interarrival spacing, of mixed operations,
508f
interarrival time, 497
intercepting drainage, 376
intercity travel, 4
intermediate range planning, 397f
international air carriers, 7
International Air Transport Association
(IATA), 46, 453
international air transportation, 7–8
Index
international airports, 300
International Civil Aviation Organization
(ICAO), 7, 96
aerodrome reference code used by,
175–176, 176t
annex 14 of, 221–222
category II system of, 297
design standards of, 173
governing bodies of, 44–45
objectives of, 44
separation criteria adopted by, 232–233
International Commission for Air
Navigation (ICAN), 96
international facilities, 415
intersecting runways, 181, 182f, 207, 208f,
517
intersection configurations, 238f
intraairport transportation systems, 414–415
isolation joints, 277
J
jet aircraft, 68t
jet fuel prices, 69f
jet routes, 106–107, 108
Joint Planning and Development Office
(JPDO), 129
joints/joint spacing, 277–279, 278f, 279f, 280t
JPDO. See Joint Planning and Development
Office
judgmental forecasting, 153–154
judgmental oversteering tracking, 247
K
k value, 263
Kay Larkin Airport, 106, 107f
L
LaGuardia Airport, 182f
land development, 616–617
landing critical point, 122–123
landing distance (LD), 83
landing distance available (LDA), 88
landing fee cash flow analysis, 570t
landing gear
annual departures and, 269–270
complex configuration of, 62f
configurations of, 59–61
curved path of, 246f
dual-tandem, 59
dual-wheel, 59
main, 57
single-wheel, 59
traditional configurations of, 60f
landing process, 240–241, 293
alignment guidance during, 294
approach speed in, 295
REIL in, 309–310
runway centerline in, 304–307, 308f
runway edge lights in, 304
runway lighting during, 303–304
threshold lighting in, 303, 309f
touchdown zone lights in, 308–309
landside building enplaning level, 388f–390f
land-use compatibility, 592–593,
597–598, 599t–600t
land-use planning, 142–143
lateral forces, 235
lateral separation, in airspace, 113–114
layered elastic design, 273–275, 274f
LBO. See lease, build, and operate
LCC. See low-cost carrier
LD. See landing distance
LDA. See landing distance available
lease, build, and operate (LBO), 562
legislative actions, 17–36
LEQ. See energy average sound level
level of service criteria, 397–398
LF. See low-frequency radio ranges
liftoff distance (LOD), 83
light aircraft, pavements for, 286–287, 286f
lighting. See also approach lighting systems
apron, 460–461
flood, 303, 460
of heliports, 644–646, 645f
during landing process, 303–304
obstructions, 293
runway, 303–304
runway centerline, 308f
security, 477
systems, 291
taxiway, 310–314, 311f, 313f
threshold, 303, 307f, 309f
linear claim footage, 412f
linear terminal concept, 419, 421f
loading bridge, aircraft, 458f
lobby area, 405
location signs, 332, 334, 334f, 338
LOD. See liftoff distance
LOM. See outer marker
Long Range Aerospace forecasts, 162
longitudinal embedded steel, 282
longitudinal gradients, 208–212, 210f, 213f
longitudinal profiles, 234
longitudinal separation, in airspace,
111–113
long-range fiscal plans, 136
long-term forecasting, 152
long-term parkers, 403
low-cost carrier (LCC), 6
low-frequency radio ranges (LF), 107
M
Mach 1, 76
magnetometer, 473
main landing gear, 57
MALS. See ALS with sequenced flashers
MALSF. See ALS with sequential flashers
MALSR system, 298
mandatory instruction signs, 332–333
market share method, 153, 156–158
marking patterns
apron gate system and, 460–461
of heliports, 644
runway, 292, 315
marking/signage, 291–292, 329, 341f
mathematical formulations, 490–492, 497
mathematical modeling techniques, 162
661
662
Index
mathematical models, of airports, 487
mathematical theory, 490–492
maximum A-weighted sound levels,
582–583
maximum gross takeoff weight (MGTOW),
62, 112
maximum ramp weight, 62
maximum structural landing weight (MLW),
62–63
maximum structural takeoff weight
(MSTOW), 62, 78
maximum surface storage, 370f, 371f
mean daily temperature, 192–193
mean service rate, 492
mechanical stabilization, 268
medium-frequency radio ranges
(MF), 107
medium-term forecasting, 152
MF. See medium-frequency radio ranges
MGTOW. See maximum gross takeoff
weight
Miami International Airport, 648f
Michigan Regional Aviation System Plan,
135
microwave landing system (MLS), 642
middle marker (MM), 119
midfield terminal complex, 414f
military landing areas, 21
military operations areas (MOAs), 106
Miner’s rule, 270
minimum interarrival separation,
508–509
minimum longitudinal separation, 112
minimum separation rules
air traffic control using, 504
position errors calculated with,
503–504
minimum time separation
air traffic and, 511t
of aircraft, 500f, 503f
aircraft’s decreasing, 501–502,
504–505
aircraft’s increasing, 499–501,
505–507
at runway threshold, 504–505
mix index, 515
mixed operations
capacity of, 509
hourly capacity with, 513–514
model for, 507–514
runway system interarrival spacing with,
508f
runway/equations for, 509–510
time-space concept for, 495f
MLS. See microwave landing system
MLW. See maximum structural landing
weight
MM. See middle marker
MOAs. See military operations areas
mobile conveyance concept, 419
modeling techniques, 427
modernization, of air traffic management,
127–130
modulus subgrade of reaction, 263, 275
money, time value of, 146
MSTOW. See maximum structural takeoff
weight
multilevel passenger processing systems,
425f
multiple linear regression analysis, 159
multistation queuing system, 429
N
NAS. See National Airspace System
NASAO. See National Association of State
Aviation Officials
NASP. See National Airport System Plan
National Aeronautical Charting Office, 110
National Air Traffic Services Ltd. (NATS), 96
National Airport System Plan (NASP), 29,
30, 551
National Airspace System (NAS), 97, 106
National Airspace System Plan, 38
National Association of State Aviation
Officials (NASAO), 44
National Environmental Policy Act (NEPA),
42, 574, 613
National Plan of Integrated Airport Systems
(NPIAS), 12, 12f, 33, 135, 551
National Transportation Safety Board
(NTSB), 27, 43
NATS. See National Air Traffic
Services Ltd.
natural resources, 29–30, 624
navigational aids, 114–127
airway/airport charts as, 110f
ARSR as, 118
DMEs as, 115–117
GPS, 125f
ground-based systems as, 114–124
ILS with, 118–123
NDBs as, 114, 114f
NextGen as, 129
NNEW as, 130
obstructions and, 216–218, 220–221
satellite-based systems as, 124–126
SWIM as, 129–130
VORs as, 108, 115, 116f, 120f
NCP. See noise compatibility program
NDB. See nondirectional beacons
NEF. See noise exposure forecast
NEM. See noise exposure map
NEPA. See National Environmental Policy
Act
net present value (NPV), 146
network models, 427–428, 432
NextGen, 129
NextGen Financing Reform Act of 2007,
35–36
NextGen network enabled weather
(NNEW), 130
nighttime flights, 608
NIPTS. See noise-induced permanent
threshold shift
NNEW. See NextGen network enabled
weather
noise. See also pollution
abatement departure procedures, 607
abatement regulations, 27
aircraft, 592–593
aircraft/airport, 579
aircraft/performance data of, 601
airport problems with, 598–600
Index
noise (Cont.):
barriers, 604–606
-based use restrictions, 607–609
community annoyance and,
595–596, 595f
control actions against, 605t
environmental problem of, 143–144
FAR Part 36 and, 609–610, 610f, 611f
hearing loss from, 596–597
helicopters causing, 634–635
hourly levels of, 587
human health influenced by, 597
land-use compatibility guidelines and,
597–598, 599t, 600t
land-use planning minimizing, 143
model outputs for, 601–602
monitoring systems, 602–604
public involvement controlling,
613–614
regulations, 609
-sensitive land, 189
sleep interference and, 594–595
solutions to, 604–615
Noise Abatement Act of 1979, 33
noise compatibility program (NCP),
613
noise exposure forecast (NEF), 579, 592
noise exposure map (NEM), 612, 613
noise-induced permanent threshold shift
(NIPTS), 597
NOISEMAP, 600, 601–602
nondirectional beacons (NDB), 114, 114f,
119f
nose gear, 57, 246–248
nose wheel tracking, 244–246
nose-in parking, 455–456
NPIAS. See National Plan of Integrated
Airport Systems
NPV. See net present value
NTSB. See National Transportation Safety
Board
O
object-free area (OFA), 203
OBS. See omnibearing selector
observed service times, 433t
obstacle clearance surface (OCS),
222, 222f
obstacle identification surfaces,
226f, 227f
obstacle-free zone (OFZ), 202f, 203
obstructions
to air navigation, 216–218, 220–221
to airport operations, 134–135
clearance requirements, 641–643, 642f
lighting of, 293
occupancy time, 243–244, 245t
Occupational Safety and Health
Administration (OSHA), 597
OCS. See obstacle clearance surface
OEW. See operating empty weight
OFA. See object-free area
Office of Noise Abatement, 27
OFZ. See obstacle-free zone
O’Hare International Airport, 141f, 183, 184f,
185f, 421f
omnibearing selector (OBS), 115, 116f
Omnibus Budget Reconciliation Act of 1990,
28–29
one way travel distance, 6f
open-V runways, 181, 183f
operating empty weight (OEW), 61
operational data, of aircraft, 601
opportunity cost of capital, 146
organizational chart, of FAA, 40f
organizations
airport development and, 37–46
professional, 45–46
trade, 45–46
originating/terminating station
process, 394
OSHA. See Occupational Safety and Health
Administration
outer marker (LOM), 119
overland flow curves, 363f
overlay pavement, 282–285
bituminous, 283
flexible, 283
rigid pavement covered by, 284, 284f
types of, 283
typical, 283f
overloaded hours, 524, 524t, 525t
P
PAPI. See precision approach path
indicator
parallel parking, 456
parallel runways, 178–181, 179f
spacing of, 205–207
wake turbulence and, 206
parallel taxilane centerline, 231
parallel taxiway centerline, 233
parking
aircraft type, 455–457, 455f
angled nose-in, 455–456
angled nose-out, 456
envelope dimensions, 454
garages, 404
parallel, 456
in terminal planning process,
403–404, 403f, 425f, 441f
partial privatization, 561–562
passenger air carriers, 7, 60t
passenger amenities, 415–416
passenger component demand, 394
passenger delay, 431
passenger facilities, 395t, 570t
passenger facility charges (PFCs),
556–557
passenger objectives, 392
passenger processing systems, 404, 432
average delay times in, 437t
enplaning, 435f
layout of, 432f
multilevel, 425f
observed service times in, 433t
passenger/visitor flows in, 435f
service processor characteristics in,
436t
typical arrival distribution in, 438t
passenger screening, 473–474, 473f, 474f
passenger service processors, 434
663
664
Index
passenger terminal system, 383–387, 418f
access interface of, 384
access modes/modal splits in, 393
components of, 383–384, 387f
design considerations of, 387–393
facility classification in, 394–396
flight interface of, 386–387
intermediate range planning of, 397f
level of service criteria of, 397–398
passenger component demand access in,
394
passenger volumes/types in,
393–394
processing system of, 384–386
space approximations of, 396–397
terminal demand parameters of, 393
passenger travel, 6f
passenger volumes/types, 393–394
passenger-to-aircraft conveyance,
457–458
passenger/visitor flows, 435f
pavement management system (PMS), 287–
288
pavements. See also flexible pavement;
overlay pavement; rigid pavement
airfield, 257, 258f
continuously reinforced concrete, 279–282
database, 288
design, 261–263
drainage sections of, 372f
FAA design methods of, 268–270
full-strength, 82, 85
joint types in, 280t
for light aircraft, 286–287, 286f
overlay, 282–285
steel placed in, 280–282
structural, 202
structure, 257–258
payload, 62
aircraft performance and, 77–79
computing, 78–79
maximum structural, 62
range relationship with, 78f
PC. See point of curvature
PCC. See portland cement concrete
perceived noise level (PNL), 590
perimeter security, 477
peripheral area, of heliport, 640
PFC bonds, 560
PFCs. See passenger facility charges
PGP. See Planning Grant Program
pier/finger concept, 417–418, 421f
pipes
depth of cover for, 375t
flexible pavement coverage and, 373t–374t
porous concrete, 378
skip, 378
soil drainage/sizes/slopes and, 378
subdrainage, 377–378
types of, 377–378
piston engine, 63, 82
pitch, 581
pitot tube, 75
Planning Grant Program (PGP), 548, 551
plate bearing test, 263
PMS. See pavement management system
PNL. See perceived noise level
point of curvature (PC), 313
Poisson arrival distribution, 429–430
Poisson’s ratio, 273
policy considerations, environmental,
574–576
pollution, 144, 576–615, 577
air quality and, 576–577
aircraft/airport noise and, 579
A-weighted sound level and,
581–582
day-night average sound level and,
587–590
maximum A-weighted sound levels and,
582–583
QL and, 585–587
sound exposure level and, 583–585
sound pressure levels and, 580–581
time above threshold level and, 590
water quality and, 577–579
ponding, 350–358, 356f, 357f, 357t,
360–365
POP. See study area population
porous concrete pipe, 378
port authority heliports, 632f
portland cement concrete (PCC), 258, 275,
283
position errors, 503–504
precision approach path indicator (PAPI),
294, 302–303, 303f
preferential runway concept, 607
pressure altitude, 72
primary airports, 11
primary service airports, 552
primary surface, 218
private automobiles, dwell times for, 401
privatization, of airports, 561–562
probability of violation, 511
processing system, 384–386
programming phase, 399, 400
prohibited areas, 106
propfan engine, 64
protection zones, of runways, 213–216, 216f,
217t
public airports, 21–22, 30
public involvement, 613–614
public ownership, of airport, 543
Public Works Administration (PWA),
544
PWA. See Public Works Administration
Q
QL. See equivalent steady sound level
queuing theory, 428
R
RAA. See Regional Airline Association
radar-based surveillance, 118, 127–129
radii of curvature, 236f, 237t
RAILS. See runway alignment indicator
lights
rainfall intensity, 344–347, 345f, 346f
infiltration rate and, 359–360
runoff computation and, 349–350, 350f
Index
ramp charts, 448–453, 451t, 452t
range, 77–79, 78f
Rankine units, 71
rate setting, 564–570
ratio models, 156
rational method, 347
RDSIM. See runway delay simulation
model
recreational areas, 617–618
reduced vertical separation minima
program (RVSM), 111
redundancy, 161
reference field length, 175
regional air carriers, 7, 8t
Regional Airline Association (RAA), 46
regional annual enplanements,
157f, 158f
regression analysis, 159
regulations. See also Federal Aviation
Regulations
of air transportation, 18–19
deregulation and, 32–33
FAA, 39–42
noise, 609
noise abatement, 27
piston engine, 82
security, 469
Title 49 Code of Federal, 470
Transportation Security, 42
turbine-powered transport, 83
REIL. See runway end identifier lights
reliever airports, 12–13
relocation, 617
Reorganization Act of 1939, 19
required navigation performance (RNP),
125, 126f
required obstacle clearance (ROC), 222
residual cost approach, 564, 565
restricted areas, 106
restricted gate use, 540
retardance coefficient, 359, 359t
retroreflective markings, 340
RGLs. See runway guard lights
rigid pavement, 258
CDFU estimation for, 285f
designing, 275–277
FAARFIELD software and, 277f, 285
joint structure locations of, 278f, 279f
overlays over existing, 284, 284f
slab thickness of, 276f
steel dowels in, 281t
subbase of, 275
risk assessment process, 478–480
RMS. See root-mean-square
RNAV. See area navigation
RNP. See required navigation performance
roadways elements, 402–403
ROC. See required obstacle clearance
Ronald Reagan Washington National
Airport, 116f, 126f
Roosevelt, Franklin D., 19
root-mean-square (RMS), 580
roughness factors, 361
RPZ. See runway protection zone
RSA. See runway safety area
runoff. See surface runoff
runway(s). See also parallel runways;
taxiways/taxilanes
aiming points on, 320–321
aircraft demand for, 523t
airfield separation requirements and, 212t,
213, 214t, 215t
alignment guidance on, 294
approach category dimensional standards
of, 205t
blast pad markings on, 322–323
blast pad of, 202
centerline markings of, 320
closed markings of, 328–329
consecutive departures separation on, 113t
declared distances for each, 88
designators, 315–319, 319f
dimensional standards of, 204t, 206t
displaced threshold markings on, 321–
322, 322f
distance remaining signs on,
330–331, 330f, 331f
edge lights, 304, 305f, 306f, 307f
end siting requirements, 223–227, 224t–
225t, 226f, 228f
exit range to, 243t
exits/arrival threshold of, 245t
FAA signing conventions of, 337–338
four components of, 243–244
gradient, 80–81
holding line/airfield separation criteria
with, 215t
hourly capacity (IFR) of, 519f
hourly capacity (VFR) of, 518f
layout of, 516f
lighting, 303–304
longitudinal gradient of, 210f, 213f
marking patterns on, 292, 315
markings on, 316t, 317t, 318t
mix index of, 515
mixed operation equations of, 509–510
occupancy time, 497
orientation, 183–190
protection zone dimensions of, 217t
protection zone of, 213–216, 216f
RSA of, 202–203
separation criteria and, 212t
shoulder markings of, 324f
shoulder of, 202
side stripes on, 321
sight distances on, 207–213
slope changes of, 212
stop bar, 314, 314f
surface conditions, 81–82
surface gradient standards for, 209t, 211t
taxiway edge lights on, 311–313, 312f
taxiway lighting on, 310–314
taxiway/airfield separation criteria with,
215t
threshold, 504–505
threshold markings of, 320
time-space concepts used on, 493f
touchdown zone markings on, 321, 321t
transverse grooved, 82
utilization, 73
wind data for, 190f, 191f
wind rose and, 187–188
665
666
Index
runway alignment indicator lights (RAILS),
298
runway capacity
arrivals position error and, 506
for arriving aircraft, 498
charts used for, 516
mathematical theory formulating, 490–492
parameters required in, 514–519
studies, 241
time-space concept formulating, 492–497
runway centerline, 304–307, 308f
runway configurations, 177–183
combinations of, 181–183
exit locations and, 243
intersecting, 181, 182f, 207, 208f, 517
O’Hare airports complex, 183, 184f
O’Hare airports planned simplified, 185f
open-V, 181, 183f
parallel, 178–181, 179f
single, 178, 178f
spacing in parallel, 205–207
VFR/IFR conditions and, 180–181
runway delay simulation model (RDSIM),
537
runway end identifier lights (REIL),
309–310, 310f
runway guard lights (RGLs), 311, 313, 314f
runway length, 57, 87
for <12,500 lb MGTOW aircraft and,
192–193
for >12,500 lb but <60,000 lb, MGTOW
aircraft and, 193–198
for >60,000 lb MGTOW aircraft and,
198–201
aircraft performance and, 79–80
atmospheric conditions and, 79
average high temperatures and, 196
Boeing 737-900 landing, 200f
Boeing 737-900 takeoff, 201f
elevation and, 198
environmental conditions and, 79–80
estimating, 191–201
estimating procedure for, 198–201
FAA’s procedures estimating, 191–192
small aircraft and, 176
“Runway Length Requirements for Airport
Design,” 191
runway protection zone (RPZ), 203
runway safety area (RSA), 202–203
runway systems, 517
approach category dimensional standards
of, 205t
delay computed on, 520–531
departure only capacity of, 512–513
dimensional standards of, 204t, 206t
dimensions of, 202f
geometric specifications of, 201–204
hourly capacity of, 514–519
mixed operations interarrival spacing of,
508f
ultimate hourly capacity of, 514
runway visual range equipment (RVR), 122
runway-use strategies, 515
RVR. See runway visual range equipment
RVSM. See reduced vertical separation
minima program
S
satellite concept, 418–419, 421f, 422f
satellite-based systems, 124–126
saturated period, 524, 524t, 525t
scenario analysis, 480–481
schematic design, 399
schematic design process, 426–427
screening, site, 137–138
SD. See stop distance
secure area, 470, 471f
security, 467
of airports, 481–482
airports history of, 468–470
at commercial service airports,
472–477
at general aviation airports, 481
lighting, 477
perimeter, 477
regulations, 469
as risk assessment process, 478–480
Security Guidelines for General Aviation
Airports, 481
security identification display area (SIDA),
472, 476
SEL. See sound exposure levels
selection, site, 138
selective availability, 124
self-service check-in kiosks, 408
separation criteria, 212t, 213, 214t, 215t,
232–233
service processor characteristics, 436t
service time distribution, 431
servicing activity time schedule, 443f
severe weather avoidance program (SWAP),
109
shared gate use, 452f
short takeoff and landing aircraft (STOL),
192
short-term forecasting, 152, 169
short-term parkers, 403
shoulders
of runway, 202
runway markings of, 324f
of taxiways/taxilanes, 326, 328f
SIDA. See security identification display
area
side stripes, runways, 321
sight distances
on intersecting runways, 207
longitudinal profiles and, 234
on runways, 207–213
sign illumination, 340
signing conventions, 337–338
simple linear regression analysis, 160
simplified short approach lighting system
(SSALR), 298
simulated airline schedule, 449t
simulation models, 153, 438–441, 440f
airport terminal projects with,
439–441
of annual service volume, 537–538
runway delay, 537
single runway configuration, 178, 178f
single server system, 429–430
single-wheel landing gear, 59
Index
site selection, heliports, 631–634
skip pipe, 378
sleep interference, 594–595
slope changes, 212
small aircraft, 176
elevation/temperature and, 193f, 194f
runway length and, 192–193
SMSA. See standard metropolitan statistical
areas
social factors, airport planning,
616–618
sociological changes, 4
soils
boring spacing/depths of, 260t
characteristics of, 264t–265t
classification of, 260t
coarse-grained, 259–260
drainability of, 379
drainage pipe sizes/slopes and, 378
fine grain, 261
frost design and, 268t
frost influence on, 266–267
groupings of, 261
investigation/evaluation, 259–266
stabilization, 268
sound exposure levels (SEL), 583–585, 588–
589, 602f
sound insulation, 606–607
sound levels, 582f
sound pressure levels (SPL), 580–581
Southwest Georgia Regional Airport, 104,
105f
space programming, 400
special facility bonds, 559–560
specific fuel consumption, 67
speech interference, 593–594
speed
of aircraft, 75–77, 135
approach, 295
climb-out, 630
critical engine-failure speed/decision, 85
ground, 73
of sound formula, 76
subsonic/supersonic, 76
touchdown, 240–241
turning radius v., 235–236
V-, 77
wind, 73–75, 188–189
SPL. See sound pressure levels
SSALR. See simplified short approach
lighting system
stalling, 76
standard atmosphere, 70, 71t
standard conditions/day, 71
standard metropolitan statistical areas
(SMSA), 12
standard pressure, 71
standard regression analysis, 160
standard supply curves, 360, 361f, 362f
state agencies, 43–44
State Block Grant, 558
state government, 557–558
steady noise environment, conversations in,
593f
steel, 280–282
steel dowels, 281t
steering angles, 246–248
sterile area, 472
STOL. See short takeoff and landing aircraft
stop bar, 314, 314f
stop distance (SD), 83
stopway (SW), 85, 322
stratosphere, 70
structural design, of heliports, 646–647
structural pavement, 202
studies
air quality, 578f
for airport master plan, 138–140
airport planning/design, 135–146
airport project plan, 141–142
for airport site selection, 137–138
for airport system plan, 135–137
of airports, 168
economic/financial feasibility,
145–146
of environment, 576t
for environmental impact assessment,
143–145
for environmental impact statement,
29–30, 144–145, 575
for land-use planning, 142–143
runway capacity, 241
study area population (POP), 160, 160f, 161f
subbase, 259
of flexible pavement, 272
of rigid pavement, 275
subdrainage, pipe types for, 377–378
subgrade drainage, 376, 377f
subgrade stabilization, 267–268
subsonic speed, 76
subsurface drainage, 376, 379
subsurface water, 377
suicide bombers, 468
supersonic speed, 76
surface conditions, 81–82
surface drainage, 368–376
surface gradient standards, 209t, 211t
surface gradients, 254
surface runoff, 343–344
of airports, 347
Corps of Engineers procedure for, 358–359
drainage computation/no ponding and,
360–365
ponding and, 357f, 357t
rainfall intensity computation and,
349–350, 350f
Surface Transportation Assistance Act, 33
surface wind, 80
SW. See stopway
SWAP. See severe weather avoidance
program
SWIM. See system wide information
management
system wide information management
(SWIM), 129–130
T
TACAN. See tactical air navigation
tactical air navigation (TACAN), 116
tail-wheel, 57
tailwind, 73
667
668
Index
takeoff, 85–86
takeoff area, of heliports, 636–637,
640–641
takeoff distance (TOD), 83, 85, 89
takeoff run (TOR), 83
takeoff run available (TORA), 88
Tampa International Airport, 103f, 422f
TAS. See true airspeed
taxiway edge lights, 311–313, 312f
taxiway exit, 234–238
centerline intersections and, 241–242
intersection configurations and, 238f
location of, 238–244, 241t
touchdown speeds and, 240–241
turnoff angle of, 237–238
taxiway guidance sign system,
336–337
taxiway intersection markings,
339t, 340t
taxiway lighting
centerline spacing of, 313t
on curved sections, 311f
on runways, 310–314
taxiway markings, 323, 325f
taxiways/airfields, separation criteria and,
215t
taxiways/taxilanes, 228–250
centerline/edge markings of,
323–325
closed markings of, 328–329
curvature dimensional standards of, 239t
curve design parameters of, 248–249
curve/intersection design of,
244–249
designations on, 331–332, 332f
dimensional standards of, 229t, 231t
end-around, 249–250, 250f
ending signs on, 336–337
enhanced markings on, 328–340, 329f
fillet design geometry, 247f
gradient standards of, 230t, 232t
guidance sign size/location on,
338–340, 338t
guidance sign system on, 331
hold markings on, 325–326
hold short/edge markings of, 327f
longitudinal profiles of, 234
parallel taxilane centerline and, 231
radii of curvature/entrance curves of, 236f
separation requirements for, 229–232
shoulders of, 326, 328f
sign illumination on, 340
sign types on, 333–337
visual aid requirements on, 310–311
widths/slopes of, 228
technology, of aircraft, 49–50
temperatures, 193f, 194f, 196
temporary flight restrictions (TFRs), 106
terminal approach control facilities
(TRACON), 98
terminal aprons/ramps, 252–254
aircraft minimum clearance of, 252t
requirements, 253f
surface gradients, 254
terminal area, of heliports, 640
terminal buildings costs, 621t–622t
terminal costs, 564
terminal curb, 401–402
terminal demand parameters, 393
terminal facilities, 400, 568
terminal instrument approach procedures
(TERPS), 222–223, 223f
departure obstacle identification surfaces
in, 226f
OCS and, 222f
terminal planning process, 399–442
access interface system in, 401
airline activities in, 415
airport operations/services in, 416
analytical queuing models in,
428–438
baggage claim facilities in, 411–414, 411f
building space requirements in, 417t
check-in counter configurations in, 406f
check-in facilities/ticket office in, 405–408
combined concepts in, 419–422, 420f
concept development for, 416–417
corridors in, 410
departure lounges in, 409, 410f
design development in, 441–442
entryways/foyers in, 404–405
horizontal distribution concepts in, 417–
422, 418f
international facilities in, 415
intraairport transportation systems in,
414–415
linear terminal/gate arrivals concepts in,
419, 421f
lobby area in, 405
multilevel passenger processing systems
in, 425f
network models in, 427–428
overall space requirements in, 416
parking in, 403–404, 403f, 425f, 441f
passenger amenities in, 415–416
passenger processing systems in, 404
pier/finger concept in, 417–418, 421f
programming/concept development
phase of, 400
roadways in, 402–403
satellite concept in, 418–419, 421f, 422f
schematic design process in, 426–427
simulation models in, 438–441, 440f
space programming in, 400
terminal curb in, 401–402
transporter concept/mobile conveyance
concepts in, 419
vertical distribution concepts in, 423–426,
423f
TERPS. See terminal instrument approach
procedures
terrorists, 467–468
Terzaghi, K., 378
TFRs. See temporary flight restrictions
3D-FF. See three-dimensional finite element
design theory
three-dimensional finite element design
theory (3D-FF), 276
threshold lighting, 303, 307f, 309f
threshold markings, 320
threshold shift, 596
through station, 396
Index
thrust-to-weight ratio, 64
ticket office, 405–408
time above threshold level, 590
time of concentration, 347
time of flow, 347
time separation
of aircraft, 500f, 503f
aircraft’s decreasing, 501–502,
504–505
aircraft’s increasing, 499–501,
505–507
time series analysis, 153
time series method, 154–156
time value of money, 146
time-space concept, 493f
for arrivals, 494f
error-free interarrival spacing and, 496f,
500f
for mixed operations, 495f
runway capacity formulated with,
492–497
tire inflation pressure, 81–82
Title 49 Code of Federal Regulations, 470
TLOF. See touchdown and liftoff
TOD. See takeoff distance
top-down models, 156, 157
TOR. See takeoff run
TORA. See takeoff run available
touch-and-go operations, 515, 517
touchdown and liftoff (TLOF), 636, 640
touchdown speeds, 240–241
touchdown zone lights, 308–309
touchdown zone markings, 321, 321t
track, 74–75
track-in, 246
TRACON. See terminal approach control
facilities
trade organizations, civil aviation,
45–46
transfer station, 396
transitional surface, 218
transport airports, 177
Transportation Security Administration
(TSA), 34–35, 37, 42, 470, 472–473, 475
Transportation Security Regulations (TSRs),
42
transportation system, 478f
transporter concept, 419
transverse embedded steel, 282
transverse gradient, 213
trend line analysis, 154, 155f
of regional annual enplanements, 157f,
158f
study area population in, 160f, 161f
tributary area, 347, 352t–354t
trip generation, 159
troposphere, 70, 71
true airspeed (TAS), 75
TSA. See Transportation Security
Administration
TSRs. See Transportation Security
Regulations
turbine-powered aircraft, 85–86, 89
turbine-powered transport regulations, 83
turbofan/jet engine, 63, 64, 65t–66t, 67t
turboprop engine, 63
turning radius
of aircraft, 58–59, 59f
passenger air carriers minimum, 60t
speed v., 235–236
turnoff angle, 237–238
TVORs (airfield VOR/NDB systems), 117,
117f
two bar/three bar VASI, 302f
typical arrival distribution, 438t
U
UDF. See unducted fan
UHB. See ultrabypass ratio
ultimate capacity
formulations of, 497–514
hourly/annual, 514, 533–534
mathematical formulations of, 497
ultrabypass ratio (UHB), 64
unconstrained forecasting, 165
uncontrolled airports, 104
uncontrolled airspace, 106
underground storm drains, 366t–367t
unducted fan (UDF), 64
Unified Soil Classification (USC),
259, 262f
United States
air transportation in, 5
aircraft registered in, 10–11
airspace classes in, 101–106, 101f, 103f,
105f
commercial service aviation in, 4–6
domestic passenger traffic in, 5f
federal agencies of, 37
federal funding programs in,
544–557
first air-mail route in, 17
general aviation in, 3
international airports in, 300
passenger travel in, 6f
protection zone requirements in, 213–216
rainfall intensity in, 345f
reliever airports in, 12–13
security regulations in, 469
total general aviation flight hours in, 11f
unrestricted gate-use strategy, 539
upwind bar, 301
USC. See Unified Soil Classification
useful load, 194, 197f
utility airports, 176–177
utility holes/risers, 378
utility requirements, apron gate system,
458–461
V
VASI. See visual approach slope indicator
vertical distribution concepts,
423–426, 423f
vertical separation, in airspace, 111
vertical takeoff and landing (VIOL), 629
very high frequency omnirange radios
(VORs), 108, 115, 116f, 120f
VFR. See visual flight rules
victor airways, 106, 108
VIOL. See vertical takeoff and landing
669
670
Index
visibility
control tower requirements of, 254–255
zone, 207–208, 208f
Vision 100 Century of Aviation Act of 2003,
35, 557
visual aids, 292–296, 295f, 310–311
visual approach slope indicator (VASI), 294,
301–302, 302f
visual flight rules (VFR), 180–181, 518f
visual meteorological conditions (VMC),
100, 186
VMC. See visual meteorological conditions
voice communication, 127
VORs. See very high frequency omnirange
radios
vortices, wing tip, 89–90, 90f
V-speeds, 77
vulnerability assessment, 477–481, 478f
W
WAAS. See wide area augmentation system
wake turbulence, 90f, 90t, 112–113
avoidance procedures for,
179–180
parallel runways and, 206
waste, 144
water quality, 577–579
Wendell Ford Aviation Investment Act. See
AIR-21
Westergaard, H. M., 275
Westergaard’s analysis, 275–276, 276f
wetlands, 619–620
wheel track, 57
wheelbase, 57
wide area augmentation system (WAAS),
109, 125
wide-bodied aircraft, 301–302
wide-bodied gates, 448
wildlife, 619
wind considerations, 184–185
wind data, 188–189, 188t, 190f, 191f
wind rose, 186–190
coordinate system/template,
187, 187f
graphical vector analysis using,
186–187
optimum runway direction from,
187–188
wind data formatted in, 188–189
wind speed/direction, 73–75, 188–189
wing tip vortices, 89–90, 90f
wingspan, 57
Works Progress Administration (WPA),
544
world economy, 3
WPA. See Works Progress Administration
Y
Yarnell, David L., 344
Young’s modulus, 266
Z
zero fuel weight (ZFW), 62
ZFW. See zero fuel weight
zoning, in land-use planning, 142
Kuliah Lapter