US investigators have identified a new trend in drug smuggling: South American gangs are buying old jets and flying the cocaine across the Atlantic to meet European demand.
At least three gangs have struck deals to fly drugs to West Africa and from there to Europe, according to court statements in the US.
One trafficker claimed he already had six aircraft flying. Another said he was managing five planes.
Because there is no radar coverage over the ocean, big aircraft can cross the Atlantic virtually undetected.
"The sky's the limit," one Sierra Leone trafficker boasted to a Drug Enforcement Administration (DEA) informant, according to court documents.
The new air route is remarkable because of the distances involved and the complexity of flying big jets, said Scott Decker, a criminology professor at Arizona State University who studies smuggling methods. A trip from Venezuela to West Africa is about 3,400 miles.
The UN Office on Drugs and Crime began warning about transatlantic drug planes after 2 November, 2009, when a burned-out Boeing 727 was found in the desert in Mali. Drug smugglers had flown in from Venezuela, unloaded the aircraft and then torched it, investigators said.
In some cases, executive jets have been used, including a Gulfstream II that landed in Guinea-Bissau in 2008 and another Gulfstream seized in 2007 as it tried to leave Venezuela, heading for Sierra Leone.
In the last year, a wave of arrests has begun shedding light on how the air routes work. The cases are being prosecuted in a New York federal court because some of the cocaine was supposed to have been sent to the US.
"The quantity of cocaine distributed and the means employed to distribute it were extraordinary," prosecutors wrote in one case. They warned of a conspiracy to "spread vast quantities of cocaine throughout the world by way of cargo aeroplanes".
In some ways it is a throwback to the 1970s and 80s, when drug pilots flew freely between Colombia and staging areas near the US border, Decker said.
Back then, drug lords such as Amado Carrillo Fuentes, nicknamed the Lord of the Skies, sent jets with as much as 15 tonnes of cocaine from Colombia to northern Mexico.
Several factors have made transatlantic air routes more attractive, said Carlos Moreno, an expert on trafficking at Icesi University in Colombia.
Cocaine use has been rising over the last decade in Europe, unlike in the US, where demand has remained flat, he said.
Also better radar coverage has made it harder to move cocaine to the States.
"Going that way, especially from South America, really gets you outside the majority of the security envelope for air traffic," said Decker.
President Hugo Chávez's decision to sever ties with most US law enforcement agencies in 2005 has made it easier to bring cocaine to staging sites on the Venezuelan coast, said Vanda Felbab-Brown of the Brookings Institution, a Washington-based thinktank.
"The DEA is not present there, the Venezuelan military is making money off it, and much of the territory is just not controlled by the government," she said.
The global economic slump has also left hundreds of cargo jets idle and these can thus be bought cheaply. Ads on websites such as Planemart.com offer Douglas DC-8s – four-engined jets –for as little as $275,000 (£170,000).
The court statements show the extraordinary lengths to which traffickers are going to exploit the new air routes.
The Valencia-Arbelaez gang used detailed spreadsheets to compute flight costs and distributed codebooks to conceal their plans.
Planning sessions were held in Denmark, Spain, Romania and Manhattan. At one meeting, gang leader Jesús Eduardo Valencia Arbelaez sketched a map of West Africa showing points where the drugs would be delivered.
Fuel and pilots were paid for through wire transfers, suitcases filled with cash and, in one case, a bag containing €260,000 (£220,000) left at a hotel bar. The gang hired a Russian crew to move a newly acquired plane from Moldova to Romania, and then to Guinea.
Most of the cocaine was destined for Europe, but part of each shipment was supposed to go on to New York.
"I sold airplanes to these people so I knew what was going on," Manuel Silva-Jaramillo, an American aeronautical engineer, told a judge. "I knew that they were bringing the drugs to the United States."
The gang also discussed setting up a methamphetamine lab in Liberia and exporting the drug to Japan and the US.
The gang had access to a private airfield in Guinea, was considering buying its own airport and had sent a team to explore whether it could send direct flights from Bolivia to West Africa, Valencia Arbelaez said in recorded conversations.
A plane seized in Sierra Leone in July 2008 with 600kg of cocaine belonged to the group, the DEA says.
The European drug market was hugely profitable. Silva-Jaramillo claimed the gang had as much as €60m stashed in Spain that it needed to launder.
Valencia Arbelaez admitted cocaine trafficking and was sentenced in July to 17½ years in prison. A conspirator, Javier Caro, received 3½ years. Silva-Jaramillo and two other men have pleaded guilty and are awaiting sentencing.
Drug trafficking is especially dangerous to West Africa because of the corrupting effect it has on already weak governments, Felbab-Brown said.
In the Liberia case, traffickers offered bribes to Fumbah Sirleaf, the head of the Liberian security agency and son of the country's president. Sirleaf was secretly co-ordinating with the DEA.
The flights were to come from Venezuela and Panama. The ring had already sent aircraft into Liberia, Guinea and Guinea-Bissau, one of the traffickers was recorded saying.
The case has attracted attention in Russia because one of the defendants, a Russian pilot, Konstantin Yaroshenko, says he was tortured by Liberian police before being handed over to the DEA. He and the other five defendants deny the charges against them.
The Russian foreign ministry accused the US of "kidnapping" Yaroshenko. Russia's prime minister, Vladimir Putin, called his arrest an example of the US overstepping its bounds.
The DEA denies Yaroshenko was abused and the US state department said it mistakenly faxed Yaroshenko's arrest notice to the wrong embassy.