The Air Force is correcting oxygen troubles on Lockheed Martin Corp.’s F-22 fighter by replacing a valve in pressure vests worn by pilots at high altitudes.
The announcement yesterday by Pentagon spokesman George Little was aimed at resolving a yearlong mystery over why at least a dozen pilots flying the F-22 Raptor became dizzy and disoriented, a condition called hypoxia.
After studying everything from hoses and masks to the planes’ radar-absorbing stealth skin, the Air Force determined the trouble was a valve in the pressure vest, Little said.
“The valve was causing the vest to inflate and remain inflated under conditions where it was not designed to do so, thereby causing breathing problems for some pilots,” Little said.
The valve is made by Gentex Corp., according to Lieutenant Colonel Edward Sholtis, a spokesman for the Air Combat Command. Lee Ann Spaulding, an executive assistant at closely held Gentex based in Simpson, Pennsylvania, said she would attempt to determine whether the company had any comment.
In May, Defense Secretary Leon Panetta ordered pilots flying the plane made by Bethesda, Maryland-based Lockheed to stay at low altitudes and within proximity to a landing strip. The pressure vests haven’t been worn since June because of indications they may have been at fault.
Senator Mark Warner, a Virginia Democrat, and Representative Adam Kinzinger, an Illinois Republican, expressed concern two weeks ago that the mystery still hadn’t been solved because of two recent incidents that occurred when pilots weren’t wearing a vest.
Those cases have since been explained and aren’t related to the early incidents, Little said. A June 26 incident at Langley Air Force Base in Virginia was caused by a faulty valve in the cockpit. A July 6 incident at Hickham Air Force Base in Hawaii had initially been thought to be a potential oxygen problem “but the issue resolved itself in flight,” Little said.
Warner and Kinzinger, who have been pushing the Air Force for safety fixes, issued a joint statement yesterday that stopped short of calling the problem solved.
“It is promising that consultation with NASA and the Navy appears to be pointing the Air Force toward a potential solution to the F-22 oxygen-deprivation issues,” the lawmakers said, while urging that disciplinary actions pending against pilots who went public with their concerns be rescinded.
During the Air Force’s inquiry, officials had also studied whether toxins from the plane’s stealth skin had contaminated the oxygen breathed by pilots.
“Oxygen contamination was ruled out,” Little said at a Pentagon news briefing.
Air Force Chief of Staff General Norton Schwartz said the problem wasn’t caught during years of testing because of the plane’s complexity and a lack of expertise about what he called “the man-machine interface.”
“We missed some things, bottom line,” Schwartz said yesterday at a separate news conference. “There were aspects of this, from a physiological point of view for the aviator, that were not well-understood.”
The Pentagon has spent $67 billion buying 188 of the supersonic jets from Lockheed, the world’s largest defense contractor. It plans to spend $11.7 billion to upgrade the planes at a time when the military is cutting spending after a decade of war in Iraq and Afghanistan.
The F-22 Raptor, which has never flown in combat, has been called “the most expensive, corroding hangar queen ever” by Arizona Senator John McCain, the top Republican on the Senate Armed Services Committee.
In a sign of the military’s confidence in the plane, Panetta authorized the deployment of a squadron of F-22s to Kadena Air Base in Japan, Little said yesterday. Those planes will fly at a low enough altitude so that pressure vests won’t need to be worn, he said.
As another precaution, the squadron, which will depart within days, will be accompanied by a tanker with an F-22 pilot on board for additional support, Schwartz said. The flight route will keep the aircraft within 90 minutes between potential landing points, he said.
No unexplained hypoxia incident has occurred since March 8, Little said. The Air Force also is installing a new emergency oxygen system on the F-22.
As corrective steps are taken, flight restrictions on the F-22 will be removed in phases, Little said.
Schwartz said the deployment to Japan is needed now even though the corrective actions will take more time.
“There’s an operational requirement, and the birds are ready to go,” he said.
Asked what lesson he drew from the F-22 probe, Schwartz, who is retiring, said, “Test. Test deep. Test continuously. There’s no such thing as engineering perfection.”