By Daily Mail Reporter
UPDATED:16:29 EST, 14 June 2012
The U.S. Air Force have advised its pilots to stop wearing pressure vests in the military’s bid to combat oxygen-deprivation problems on the F-22 Raptor.
Symptoms of hypoxia – a condition where the body is can’t get the oxygen it needs – have plagued the Raptor for the past two years – including one case that was fatal.
The flight suit alteration was recommended by the Air Force on Tuesday.
In a statement to Bloomberg, Lt Col Edward Sholtis, a spokesman for the Air Combat Command, said: ‘Recent testing has identified some vulnerability and reliability issues in the upper pressure garment worn by F-22 pilots’
As the Air Force works investigates the issue, it says the vest may not be the definitive cause, but it is a step in the right direction.
Lt Col Sholtis told Bloomberg: ‘We still have other variables to work through before we can determine what the major factors are and how they interact to produce the number of unexplained incidents we’ve seen.”
Since they were rolled out in 2005, F-22 Raptors – the most advanced and pricey fighters used by the U.S. military – have never been flown in combat.
The Air Force Times reported that at least nine pilots have voiced their concern to lawmakers about how safe the jets are – and at least 12 incidents where it appeared that oxygen had been cut off.
The F-22 is one of the fastest, most manoeuvrable jets in operation, and a single jet is priced at $143million, according to the U.S. Air Force.
In November 2010, U.S. Air Force Capt Jeff ‘Bong’ Haney was flying at Mach 1.1 over the Alaskan wilderness when his F-22 fighter jet flipped and slammed into the ground.
Crash investigators found a malfunction had cut off Capt Haney’s air supply but blamed the crash on his lack of attention, saying he was too distracted by his inability to breathe.
Capt Haney had been returning to Joint Base Elmendorf-Richardson, west of Anchorage, after a training flight when the accident happened.
According to a report by the Air Force’s accident investigation board, the plane suffered ‘an engine bleed air leak malfunction’, cutting off the air supply Captain Haney’s oxygen mask.
To save himself and the plane, the pilot should have engaged an ’emergency oxygen system’ by pulling a green ring beneath his left thigh, the report said.
Instead, unable to breathe, Captain Haney appeared to remain in control for a few seconds, taking the plane to a lower altitude in an attempt to get himself some air.
But his jet, still moving at more than the speed of sound, somehow lurched into a steep roll and plummeted towards the ground in a dive he was too slow to pull out of, the report said.
Three seconds later, Captain Haney, a veteran and award-winning airman, crashed into a valley in the snow-covered Talkeetna Mountains.
The jet was obliterated and he was killed instantly.