Air Force pilots employed to fly the US military’s F-22 warplanes are experiencing breathing problems and coughing fits caused by plane’s oxygen system – and officials say they have no solution for this problem.

Despite at least one fatal crash that may have resulted from a pilot’s crippling health condition, the government has refused to acknowledge the danger of keeping these planes in service without making any fixes to its oxygen system.

During a Sept. 2012 congressional hearing concerning health effects of flying F-22 Raptor stealth fighters, members of the Air Force described suffering from physiological conditions that have been considered “a normal part of flying the Raptor, such as the difficulty in breathing and the Raptor cough.”

The NASA Engineering and Safety Center (NESC) found that these health problems were directly related to flying the F-22s, since pilots first experienced the symptoms while flying the plane.

The hypoxia-like symptoms, which are triggered if the air contains more than 60 percent oxygen, include breathing problems, choking, coughing, confusion, memory loss and blackouts. These symptoms, all of which were at some point exhibited by pilots in the F-22 cockpits, can lead to a condition known as ‘acceleration atelectasis’, which is the collapse of alveoli in the lungs.

But despite the health and safety risks facing F-22 pilots, the Air Force refuses to address the problem.

During the congressional hearing, Rep. Roscoe Bartlett (R-MD), referenced a press report in which Air Force medical experts linked the Raptor cough to flaws in the plane’s design, but that “the Air Force decided in 2005 not to make a fix to the F-22 oxygen system.”

And since 2008, pilots have reported choking, confusion, memory loss and blackouts, which may have contributed to at least one fatal crash, Wired reports. Additionally, ground crews have reported growing sick while in the proximity of F-22s with running engines.

Maj. Gen Charles Lyon, who headed the investigation, told Wired that “the Air Force will continue to explore further potential causes through long term breathing air analysis and human systems integration efforts”, but that it will no longer investigate claims of coughing fits from F-22 ground crews.

Air Force officials claim that ground crew members could not have possibly gotten sick from the F-22s and that “factors other than the life support system or the aircraft caused the ground incidents,” Lyon said.

But even though NASA has linked the F-22s to the hypnoxia-like symptoms and the Air Force has already acknowledged the problem, Lyon had no solution to the condition and pilots now consider this a regular part of flying the jets.

“Apparently, from the Air Force’s point of view, coughing is the cost of sitting in the world’s most high-tech fighter cockpit,” writes Wired’s David Axe.