By Christine Jenkins | Bloomberg News

Airlines are continuing to pull out of Venezuela, and this time it’s not just about trapped cash but a whole series of grievances including staff held up at gun point, luggage theft, poor runway maintenance and low quality jet fuel.

United Airlines, Avianca and Delta Air Lines have either stopped flying to Venezuela or said they would leave the country, while three others canceled flights on specific days as the nation descends into chaos. Colombia’s pilots’ association says its members who have flown to Venezuela have had to deal with contaminated fuel and hours-long delays as the National Guard pulls suitcases off flights to loot them. This week, videos showed an apparent assassination of a man at the check-in desk of a local airline at the airport.

“Everything that’s part of the airport’s infrastructure started to get degraded,” Julian Pinzon, the head of security and technical issues at Colombian pilot association Acdac, said. “We started seeing problems in the runway, problems in the aircraft taxiway, problems with the airport’s electricity supply, in the fuel distribution trucks.”

The current round of carrier defections comes after routes had stabilized from the previous exodus triggered by the government’s halt of dollar payments, and leaves Venezuelans increasingly cut off from the rest of the world. A flight to Miami in coach class can cost about $1,000, in a country where the monthly minimum wage is about $20 at the black market rate.

The nation’s social and economic implosion has turned tasks as simple as busing flight crew to hotels into logistical challenges. Staff who once stayed overnight in Caracas, which is about a 45-minute drive away, took to sleeping in hotels near the airport to avoid the bandit-ridden highway. Even then, they’d get attacked, minutes outside the airport perimeter. Some carriers took to flying crew to spend the night in neighboring countries.

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Avianca hired bodyguards after shots were fired during a robbery of a bus carrying its crew. Although no one was injured, it wasn’t enough to calm nerves, and the overnight route was eventually canceled, according to Acdac.

Traffic in and out of Caracas dropped 40 percent in 2014 after cash piled up from local sales that couldn’t be repatriated – there’s still $3.8 billion that never made it out, according to international airline association IATA. The airlines that stuck it out were able to pay off local costs and fuel with bolivars – until Venezuela changed that rule, requiring payment in dollars.

Some carriers are refusing to throw in the towel. American Airlines, which still flies to Caracas and Maracaibo, said in a reply to emailed questions that it would not operate at any airport that didn’t meet the highest standards safety and security. Panama’s Copa Airlines, which flies to Caracas and two other Venezuelan cities, said it’s been able to overcome operational challenges and continues to monitor conditions in the country.

Venezuela’s aviation authority Inac said it didn’t have an official spokesperson who could talk about the sector. The U.N.’s International Civil Aviation Organization said that when it last visited Venezuela four years ago, the country delivered “exemplary results.”

Flights have found Venezuelan jet fuel to be contaminated due to poor conditions in distribution trucks and storage tanks, according to the Acdac. Planes that fill their tanks with the fuel sometimes require lengthy maintenance, the association said.

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“You don’t have the guarantee anymore that the fuel they’re putting on board isn’t contaminated,” Pinzon, the head of safety and technical issues at Acdac, said. “The engines that are getting that gas aren’t going to stop, but the internal system will start to degrade and the filters will start getting blocked up, or damaged.”

The official reasons for leaving have been varied. United said its Venezuela route wasn’t meeting financial expectations, while Avianca cited operational issues without providing too many details. Aerolineas Argentinas said it wants to continue flying to Caracas, but first needs reassurance that it would be viable and secure. After dropping off passengers from its its weekly Buenos Aires to Caracas flight, the airline takes its crew on to Bogota, rather than have them spend the night in Caracas. They return to Venezuela for the return leg the following morning.

Complaints about operational issues to Venezuelan authorities have been falling on deaf ears, according to Peter Cerda, IATA’s regional vice president for the Americas.

“It’s quite unfortunate, the airlines have done everything possible to maintain Venezuela connected to the rest of the world,” he said. “It’s more of a challenge every day.”

Bloomberg’s Michael Sasso and George Ferguson contributed.