Defense Secretary Leon Panetta has ordered the Air Force to restrict flights of its new F-22 stealth fighters because of continuing problems with the aircraft's oxygen system.
At least 22 pilots have suffered from oxygen deprivation while in flight since April 2008.
Panetta on Tuesday ordered that all F-22 flights remain within a "proximate distance" of an airfield in case a pilot should suffer from a hypoxia event and be forced to land. That will force an immediate end to F-22 patrol missions over Alaska.
Panetta also ordered the Air Force to accelerate installment of a backup oxygen system in all F-22s and provide monthly progress reports on efforts to identify the problem with the current oxygen system. The Air Force does not expect to begin installing automatic backup oxygen systems until December of this year.
A F-22 Raptor fighter jet flies in a training mission during Red Flag 12-3 over the Nevada Test and Training Range.
The Air Force has been unable to determine the cause of the 12 incidents of hypoxia suffered by pilots of the F-22. Pilots have reported wooziness while flying the supersonic jet, considered the most advanced fighter plane in the world.
Some of the military's top aviators have refused to fly the radar-evading planes because of the oxygen system problems.
The supersonic plane has also been criticized in the past for its high-maintenance costs.
The Air Force reports that each of the aircraft costs $143 million. The U.S. Government Accountability Office, however, estimates that each F-22 cost taxpayers $412 million, if upgrades and research and development expenses are included.