On July 27, AINOnline reported that the Air Force will gradually lift the flight restrictions on the cutting-edge F-22 Raptor. Since 2008, F-22 pilots have been reporting problems with hypoxia, or oxygen deprivation, which have lead to several deaths. Apparently the Air Force and Lockheed have gotten to the root of the problem:
Two changes are being made to the F-22 cockpit life support system to improve the oxygen supply. 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,” Little said. The upper pressure garment was suspended from flight in June. Second, a filter installed to detect oxygen contamination has been removed, increasing the volume of air flowing to pilots. Oxygen contamination has been ruled out as an issue.