Bush Pilot

Carbon monoxide suspected in F-22 groundings

An investigation that has grounded the Air Force's F-22 Raptor fighter jet fleet since May has brought a possible culprit to light. The Air Force Times reports that carbon monoxide entering the jet pilots' oxygen supplies may be to blame for several cases of "hypoxia-like symptoms" in the pilots. One incident that led to the May 3 grounding of the fleet was the Nov. 16 crash near Cantwell that killed the F-22's pilot, Capt. Jeffrey Haney, although it is still unclear if that crash was caused by carbon monoxide. According the Air Force Times, the majority of the 14 reported incidents have taken place in Alaska, and the likely culprit now appears to be carbon monoxide that resulted from starting the twin-engine jets inside the hangars during cold temperatures, which then mixes in with the pilot's On-Board Oxygen Generation System (OBOGS).

From the Air Force Times:

Part of the problem may be the procedures used at Elmendorf Air Force Base, Alaska, where most of the known incidents have occurred. Because of the harsh climate, pilots often start their jet engines inside a hangar before taking off. Investigators suspect that exhaust gases are getting trapped in the building and subsequently sucked back into the engines, where they enter the bleed air intakes that supply the OBOGS, sources said.

The new report alleviates some blame from the OBOGS itself -- a problem with which had been considered a possible cause -- and does suggest that there may be a simple procedural fix, although further filtration modifications to oxygen systems may also be necessary. The investigation is still ongoing, and the grounding of the fleet continues. Read much more, including about similar problems in the F/A-18 Hornet, at the Air Force Times.

Craig Medred

Craig Medred is a former writer for the Anchorage Daily News, Alaska Dispatch and Alaska Dispatch News. He left the ADN in 2015.

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