F-22 hypoxia investigation continues as USAF fleet returns to the skies

摘要

The US Department of Defence (DoD) has contracted Lockheed Martin to conduct a hypoxia root-cause analysis on the F-22 Raptor's onboard oxygen generation systems (OBOGS), it announced on 26 September.News of the contract, which forms part of a wider support agree ment valued at USD24 million, came on the same day the company conducted its first flight since a four-month grounding order was rescinded on 19 September.The US Air Force (USAF) suspended flight operations of its Raptor fleet on 3 May after pilots reportedly suffered hypoxia-like symptoms. Although an investigation into the OBOGS system by the USAF Scientific Advisory Board (SAB) has failed as yet to identify the root cause of the problem, the air force has deemed it safe to return the aircraft to flight status with the proviso that pilots will receive additional emergency training and