Orders grounding the Air Force’s F-22 Raptor stealth fighter spread from Virginia to Alaska this weekend, briefly sidelining up to half of the roughly 170 Raptors. It’s becoming clearer by the day that the problems vexing America’s premier stealth fighter are neither minor nor temporary.
The current lock-down echoes a fleet-wide grounding between May and September that was prompted by a suspected flaw in the $150-million-a-copy jet’s onb0ard oxygen-generating system. Pilots had reported mid-flight blackouts and disorientation, possibly resulting from too much nitrogen in their air mix.
Despite an extensive investigation, the Air Force never found the flaw in the oxygen generator. The brass ordered an additional filter installed in the oxygen system, then sent the Raptors back into the air on Sept. 19. “We’re managing the risks with our aircrews, and we’re continuing to study the F-22’s oxygen systems and collect data to improve its performance,” said Gen. Norton Schwartz, the Air Force chief of staff.
http://www.wired.com/dangerroom/2011/10/stealth-fighters-oxygen-woes/