temporarily oxygen supply system to survey.

According to xinhua U.S. air force 5 announced that F - 22 type "raptor" type warplanes grounded MBT Wave, temporarily oxygen supply system to survey.
The air force says, grounded, lifting to 3rd time issued a notice, grounded MBT Wingu will affect training routine and other tasks.
The air force is checking F - 22 all systems, but focus on oxygen supply system.
CNN television reports, the U.S. air force existing about 165 frame F - 22. Last November crashed a plane "raptor, air force after January, the aircraft in command only about 76 meters below the airspace flight. Beyond the level, the pilot may lose control of dizziness, from lack of oxygen plane ability.
F - 22 is the latest generation by aircraft, lockheed Martin and Boeing aircraft company,MBT Habari, has developed from radar detection and Seattle cruise etc. Various ability, but the price is expensive, a fight over 1.4 billion dollars.