According to ABC News, the Air Force says a faulty valve was the source of the potentially deadly oxygen problem that has bedeviled America's most expensive fighter jet, the F-22 Raptor, for years, Pentagon spokesperson George Little said Tuesday.
On Tuesday, flight restrictions that had grounded the $79 billion fleet since May were lifted in the wake of the findings.
"I think we have very high confidence that we've identified the issues," Little said. "This is a very prudent way to ensure that we, in a very careful manner, resume normal flight operations."
The mystery problem with the F-22 Raptor was the subject of an ABC News "Nightline" investigation, which found that since 2008, F-22 pilots have experienced unexplained symptoms of oxygen deprivation -- including confusion, sluggishness and disorientation -- while at the controls of the $420 million-a-pop jets on more than two dozen occasions.
Back in November of 2010, a crash northeast of the Interior Alaska city of Cantwell killed Capt. Jeffrey Haney of Joint Base Elemendorf-Richardson. Combined with numerous other reports of pilot disorientation in the F-22 fleet, the incident grounded the entire U.S. fleet for four months while the Air Force looked for the cause of the problem.
Carbon monoxide entering the cockpit was one suspected cause of Haney's crash and the other reports of pilot disorientation. It was reported that the majority of the 14 incidents of "hypoxia-like symptoms" in the F-22 pilots were in Alaska, leading some to suggest that carbon monoxide mixed with the jets' oxygen supply as the aircraft warmed up in the hangar during the winter months was a factor.
A subsequent Air Force investigation said that there was a malfunction with the oxygen supply in the jet piloted by Capt. Haney, but also that while Haney was focusing his attention for 50 seconds on re-establishing the flow to his oxygen mask, he inadvertently moved the aircraft, resulting in "spatial disorientation" that led to an unrecoverable dive. Procedure called for the activation of the Emergency Oxygen System or for Haney to lower his mask from his face. The investigation found that he did neither.
Haney's sister, Jennifer Haney, strongly disagreed with the Air Force assessment.
"I'd like to think it's easier to blame Jeff. He's not here to defend himself," she told ABC News in an exclusive interview. "To them, Jeff was a number, it feels like sometimes. But those jets are worth a lot of money."
On Tuesday, the Pentagon said the source of the hypoxia is believed to be a faulty valve in the high-pressure vest that is worn by the pilots at extreme altitudes -- one that Air Force officials believe was constricting the pilots' ability to breathe.
"To correct the supply issue and reduce the incidence of hypoxia-like events, the Air Force has made two changes to the aircraft's cockpit life support system," Little said, according to ABC. "First, the Air Force will replace a valve in the upper pressure garment vest worn by pilots during high-altitude missions. 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... Second, the Air Force has increased the volume of air flowing to pilots by removing a filter that was installed to determine whether there were any contaminants present in the oxygen system. Oxygen contamination was ruled out."
The Air Force first ordered its pilots to stop wearing the vests last month.
When asked at a press conference if the new solution could also account for the at least five instances in which the Air Force said ground crews working on the F-22s experienced their own hypoxia-like symptoms, Little said he "did not have specifics" on those incidents.
The defense contracting giant Lockheed Martin built 187 of the F-22s for the Air Force, costing U.S. taxpayers an estimated $79 billion. Including research, development and production among other costs, each plane has a price tag of more than $420 million.
Read more, at ABC News.
Contact Mike Campbell at mike(at)alaskadispatch.com