KTUU.com

Chris Klint

ANCHORAGE, Alaska — The Air Force has determined that a valve in F-22 Raptor pilots’ pressure-suit vests are to blame for a string of hypoxia-related incidents, and is taking steps to replace the valves and relax flight restrictions placed on the stealth fighters.

According to an Air Force Times report Tuesday, the valves in the pressure suits will be replaced and a filter installed to measure pilots’ air quality will be removed.

A squadron of F-22s is expected to make a trans-Pacific flight to Kadena Air Force Base in Japan within the next few days, marking a show of confidence that the cause of the aircraft’s problems has been found. The flight will take place at low altitude, which doesn’t require that the vests be used, and an F-22 pilot will be on board a tanker to provide advice to other pilots if necessary.

Previous Air Force orders had temporarily grounded the Raptor fleet as investigators considered other possible causes of the hypoxia reports, including indoor engine start procedures at JBER. The most recent restrictions, issued in May, have forced F-22s to remain at low altitude and stay within 30 minutes of an airfield.

In a statement to Alaska media, Sen. Mark Begich hailed Tuesday’s news as a prudent step on the way to bringing F-22s back to full service.

“I’m pleased to hear the F-22, our nation’s greatest fighter, is expected to return to flight over the coming months,” Begich said. “I support the Air Force’s plan which includes incremental steps to ensure the safety of our pilots before full fleet flight restrictions are lifted.”

Sen. Lisa Murkowski echoed those thoughts in a Tuesday phone interview with Channel 2.

“My concern has always been for the safety of the airmen that are flying our F-22s,” Murkowski said. “I am very, very hopeful that the Air Force will work to ensure that any testing that this is, in fact, the flaw is very thorough -- so that all questions are resolved as to what has caused the problems with our capabilities of the F-22.”

The Air Force’s chief of staff, Gen. Norton Schwartz, told the Air Force Times Tuesday that investigators do not believe the November 2010 death of Capt. Jeffrey Haney in an F-22 crash near Cantwell was related to the hypoxia reports. An Air Force report last year blamed Haney for the crash, saying he failed to activate an emergency oxygen system after a malfunction of the jet's bleed air intakes shut down the primary oxygen system.

“It was a complex emergency the likes of which I have never experienced,” Schwartz said. “And what we do know with certainty is it was not a hypoxia-related event, it was a complex emergency with multiple aspects and we respect his effort to save the aircraft. And again, the tragedy of this continues to affect us all.”

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