The U.S. Air Force is deploying a squadron of F-22s to Japan within days, a show of confidence that the service has identified the cause of oxygen problems that have forced pilots of the stealth fighters to fly only at lower altitudes and remain within 30 minutes of a landing strip.
Pilots will soon deploy to Kadena Air Base, Japan, Pentagon spokesman George Little said Tuesday.
The Air Force has determined the oxygen deprivation reported by pilots was caused by a faulty valve worn by pilots during high-altitude flights and a filter installed to measure air quality. Valves on the vests will be replaced and the filter has been removed, Little said.
Pilots will fly the cross-ocean flight to Kadena at low altitude, which does not require the vest to be worn, and will stay near landing strips as a precautionary measure.
“This is a phased approach, this is prudent, it is recommended by Air Force leadership, and the secretary approved the recommendations,” Little said.
Air Force Chief of Staff Gen. Norton Schwartz said Tuesday that an F-22 pilot will fly in a tanker along the route to be available to give advice to other pilots on the way.
Defense Secretary Leon Panetta ordered flight restrictions for all F-22s on May 15, following about a dozen unexplained hypoxia-like incidents among pilots since September. The plane was grounded from May until September last year.
Two more F-22 incidents — at Joint Base Langley-Eustis, Va., on June 26 and Joint Base Pearl Harbor-Hickam on July 6 — were caused by other problems, Little said. The incident at Langley was caused by a faulty air valve in the cockpit; the Hickam incident resolved itself with flight. Both the pilots and aircraft involved have resumed flight.
In addition to pilots, five F-22 maintainers also complained of wooziness, nausea and headaches that signal oxygen deprivation after working inside the cockpits.
Air Combat Command said those symptoms have been attributed to breathing ambient air during engine runs. Flight line procedures have been changed to rectify the exposure, and there have not been any additional maintainer issues since December, ACC spokesman Lt. Col. Tadd Sholtis said in an e-mail.
Problems with the F-22 came to light after a November 2010 crash killed Capt. Jeff Haney near Joint Base Elmendorf-Ricardson, Alaska. The Air Force's accident investigation board report stated that Haney did not react quickly enough to activate the Raptor's emergency oxygen system or recover from a dive as he struggled to breathe.
“I find the cause of the mishap was the MP's [mishap pilot] failure to recognize and initiate a timely dive recovery due to channelized attention, breakdown of visual scan and unrecognized spatial disorientation,” Brig Gen. James Browne, the president of the accident investigation board, wrote in the report.
On Tuesday, Schwartz said the crash was a “tragic event,” unrelated to the oxygen problems now being addressed.
“It was a complex emergency the likes of which I have never experienced,” he said. “And what we do know with certainty is it was not a hypoxia-related event, it was a complex emergency with multiple aspects and we respect his effort to save the aircraft. And again, the tragedy of this continues to affect us all.”