Thursday, September 08, 2011

Air system failure caused fatal Alaska F-22 crash, report says

Last November's fatal crash of an Air Force F-22 north of Anchorage was caused by a problem in the jet's bleed air system, according to an industry crash report cited by unnamed sources to Defense News. The system feeds air from the jet engine compressor to cockpit environmental and oxygen systems. A systems failure could have been survivable, and it's unknown why Capt. Jeff Haney of Joint Base Elmendorf-Richardson was unable to take actions to prevent the crash. 

From Defense News:
It is unclear whether the pilot had switched to his emergency oxygen supply, the industry source said.

"The rate at which he descended, though, he would have been at a hypoxia-safe altitude within time to have not fully succumbed to hypoxia and should have only had symptoms versus unconsciousness," the pilot source said. 

"The green ring [emergency oxygen bottle] in the Raptor is a tough pull, and it was altered to give the pilot some pressure."

Activating the emergency oxygen system is tricky in the Raptor, the source continued. 

"It is a double pull that has to be practiced and experienced a few times before you end up in that bad situation, or you will panic," he said.

The Defense News source isn't convinced the report is totally accurate. Other reports have indicated suspicions that F-22 pilots, especially at JBER, are breathing airborne toxins somehow getting into the cockpit.

It could be that other physiological factors with pilot's g-tolerance and the oxygen levels in his body could have played a role in the crash. Haney was attempting a maneuver called a "rejoin" and made a fairly aggressive turn during the procedure, the pilot source [told Defense News].

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