An Air Force advisory panel has been unable to determine the cause of several incidents in F-22 Raptors that resulted in a lack of oxygen affecting pilots, but said in a Pentagon press conference on Thursday that they are confident that the fighter’s oxygen system does not pose any unnecessary risk.
There were 14 “physiological incidents” – with pilots experiencing hypoxia-like symptoms – involving F-22 Raptors from April 2008 to May 2011, said retired Gen. Gregory Martin, chair of a study on oxygen aircraft generation systems. Three of those incidents happened between late April and early May 2011.
These hypoxia-like symptoms can manifest themselves in different ways, Martin said. For example, the pilot might become lightheaded, get a headache or experience reduced color vision. No one died and no planes crashed in any of the 14 incidents, he said.
The Air Force grounded the supersonic fighters May 2011 and began looking into possible causes. Among the study’s findings: the F-22 life support system lacked an automatically activated supply of breathable air; there was no mechanism to prevent the plane from crashing if the pilot becomes temporarily impaired; and on-board oxygen systems had not been classified as “safety critical.”
After doing ground tests and flight tests, F-22s were cleared to return to flight in September 2010, though the cause of the symptoms was not clear.
Crew members now wear heart-rate and oxygen devices that are monitored and recorded, as well as carbon air filters during flights, said Maj. Gen. Charles Lyon, director of operations for Headquarters Air Combat Command.
Two months after the F-22s returned to flight, Capt. Jeff “Bong” Haney, 31, died when his fighter crashed during a night test mission in Alaska. An Air Force investigation found that Haney’s oxygen supply stopped automatically after onboard computer detected an air leak in the engines. The report also said Haney did not pull a small handle that would have activated an emergency oxygen system and did not eject.
The Air Force report blamed the crash on Haney’s failure to regain control of the plane. Haney’s widow has filed a wrongful-death lawsuit against F-22 manufacturer Lockheed Martin and other defense contracting companies.
Martin, Lyon and Maj. Gen. Noel “Tom” Jones all praised the pricey F-22 Raptor as the leading edge of technology.
“There is no other fighter in the world that can do what (the F-22) does,” Jones said.
But Lyon said they will working – with the Navy, which has experienced similar problems with their F-18s – to find out what is causing the planes to lose oxygen.