The U.S. Air Force has stopped flying its fleet of F-22 Raptor jets because of concerns with the oxygen supply system onboard the stealth fighters.
Gen. William Fraser, the head of Air Combat Command at Langley Air Force Base in Virginia, issued the directive earlier this week.
Master Sgt. Pamela Anderson with the Command's public affairs office said Friday that the fleet is on stand-down because of "hypoxialike" events reported by some of pilots. Hypoxia is when the body receives too little oxygen.
Since January, the Raptor fleet has been restricted from flying above 25,000 feet because of concerns with the oxygen supply system aboard the fighter jets.
Last November, an F-22 pilot was killed in Alaska when he lost control of his jet during a training exercise.