The US Air Force has officially concluded that the Combat Edge upper-pressure garment and its associated breathing regulator/anti-g (BRAG) valve, hoses and connectors are to blame for more than a dozen "hypoxia-like" incidents that have plagued the service's Lockheed Martin F-22 Raptor fleet since 2008.
The USAF says it has a plan to test and implement fixes to the system by this September. But in the meantime, safety restrictions will remain in place on the Raptor. Based on USAF's conclusions, US Secretary of Defense Leon Panetta is allowing the USAF to deploy the aircraft to Kadena, Japan. That entails a far longer duration flight away from the safety of airfields than is normally allowed under Panetta's restrictions.
But while the USAF says it has found the root cause of the problem, a number of F-22 pilots and engineers are unconvinced. Some see the service's latest move as merely a means to show some sort of progress. As one F-22 expert points out, the problem with the Combat Edge, fingered as the primary culprit, has been a known issue since at least 2006. In its problem-solving zeal, the USAF might have focused too narrowly on one particular symptom: the so-called Raptor cough.
Because of that tunnel vision, there remains the possibility that the service may have missed the true culprit behind these incidents. If so, we'll be hearing about more "hypoxia-like" incidents for a while yet.
(This appears as the second leading article in Flight International 31 July)