The U.S. Air Force has temporarily stopped flying its entire fleet of F-22 Raptor jets, due to concerns about the system that supplies oxygen to the stealth fighters’ pilots.
Air Combat Command chief Gen. William Fraser issued the stand-down order Tuesday. Since January, the 158-aircraft Raptor fleet has been barred from flying above 25,000 feet because of issues with the On-Board Oxygen Generating System.
Fraser emphasized in a statement that his order is not technically a grounding of the fleet, which is only done in the case of catastrophic technical issues. Stand-downs, by contrast, are voluntary and precautionary measures.
Fighter jets' oxygen systems provide an enriched flow of air to pilots during extreme maneuvers, which place major stresses on their bodies. If a pilot's oxygen supply is interrupted during such maneuvers or at high altitudes, it can cause loss of consciousness in seconds.
ACC’s Capt. Jennifer Ferrau, stationed at Langley Air Force Base in Virginia, said the 25,000-foot altitude restriction was put in place after an initial wave of reports from F-22 pilots experiencing symptoms of decompression sickness and hypoxia, a form of oxygen deprivation also experienced by climbers.“Between June 2008 and February 2011, there were nine physiological hypoxy-like events reported through Air Force safety channels,” Ferrau said. “But over the last week we’ve experienced five additional F-22 physiological hypoxia-like events across the Air Force, and that's what prompted the current stand-down.”
Air Force Capt. Jeffrey Haney, 31, was killed on impact Nov. 16 when his 525th Fighter Squadron F-22 lost contact with air traffic control and a partner aircraft, then crashed during a training exercise about 100 miles north of Anchorage. Military officials said parts of Haney’s flight suit and ejection seat were discovered in the Raptor’s wreckage.
Ferrau says there is no conclusive evidence to connect the OBOGS issue to the crash of Haney’s F-22, since the Air Force’s investigation of the crash has not been completed.
“We don’t know how long the stand-down will last, but we will take the necessary time to ensure we perform a thorough investigation to find out what the issues are and how to fix that,” Ferrau said.Contact Christine Kim at email@example.com