A deadly F-22 crash on November 16 last year prompted the Air Force to begin investigating the On-Board Oxygen Generation Systems (OBOGS) aboard the F-22, F-35 Lightning II Joint Strike Fighter (JSF) and other tactical aircraft and trainers. The service last week stood down all F-22s after a spike in incidents potentially related to hypoxia.
"No other airframes have been stood down due to this investigation; however, a parallel investigation is taking place on the on-board oxygen generation systems on the A-10, F-15E, F-16, F-35 and T-6 aircraft," said Captain Jennifer Ferrau, an Air Force spokeswoman for Air Combat Command (ACC).
Since January, Raptors have been kept at altitudes below 25 000 feet during the ongoing investigation in order to lessen the risk in case their oxygen systems malfunctioned. If the OBOGS failed at 25 000 feet pilots would have time to recover to lower altitudes where there is enough oxygen in the atmosphere. This is not the case when the aircraft flies at its 50 000 feet ceiling, as the pilot would only have ten seconds of consciousness.
As the Air Force could not say when the F-22 would be flying again, the entire fleet is standing down indefinitely.
"We are still working to pinpoint the exact nature of the problem. It is premature to definitively link the current issues to the OBOGS system," Ferrau said. "The safety of our airmen is paramount and we will take the necessary time to ensure we perform a thorough investigation."
There have been nine suspected cases of hypoxia during F-22 operations since mid-2008, and recently there have been 14 recorded OBOGS incidents.
"Over the last week, we have experienced five additional F-22 'Physiological-Hypoxia Like' events across the Air Force, which led Commander of Air Combat Command to establish the current F-22 stand-down," Ferrau said. Ferrau reports "increased frequency of pilot reported physiological incidents such as hypoxia and decompression sickness."
F-22 manufacturer Lockheed Martin has deployed a team to assist the Air Force during its OBOGS investigation, according to company spokesperson Stephanie Stinn.
Air traffic networks across SA modernised
24 May 2013 - Thales and Air Traffic Navigation Services (ATNS) Company of South Africa longstanding partners in air traffic management (ATM) systems are immensely proud to announce the recent signature of several significant ...
defenceWeb shines at Air Capability Demonstration
21 May 2013 - defenceWeb, Africas leading defence and security news portal, was invited by the South African Air Force to attend its annual Air Capability Demonstration a spectacular live-fire showcase of the ...
Airbus Military, EADS North America deliver HC 144A Maintenance Training Unit to US Coast Guard
16 May 2013 - The US Coast Guard Aviation Logistics Center has purchased the prototype CN235 aircraft and plans to transform it into an HC-144A maintenance training unit. The HC-144A is based ...