ANCHORAGE, Alaska — Air Force investigators are looking into whether engine startup procedures for F-22 Raptor jets at Joint Base Elmendorf-Richardson could be responsible for reports of hypoxia related to the stealth fighters' oxygen-supply system.
According to the Air Force Times, most of the hypoxia incidents have occurred at JBER, where F-22s are often started up inside hangars due to harsh weather outside. Investigators believe carbon monoxide generated by the Raptors’ own jet engines could be getting ingested back into the engines’ bleed air intakes. Those intakes supply the on-board oxygen generation system, or OBOGS, which provides oxygen to the pilot.
JBER officials had no comment on the issue Thursday.
The Air Force barred the 158-aircraft Raptor fleet from flying above 25,000 feet in January after receiving nine reports of symptoms similar to hypoxia, a form of oxygen deprivation. The fleet later received a May stand-down order to investigate OBOGS concerns, following five more reports of similar symptoms within a week.