Pentagon limits F-22 fighter jet flights Defense Secretary Leon Panetta on Tuesday ordered the Air Force to take new steps to address an undiagnosed safety problem with its F-22 fighter jet, including limiting the distances it can fly between landing zones. The new restriction does not affect the war effort in Afghanistan because no F-22s are deployed there. The fighter has never flown in combat with the only F-22s operating overseas in the United Arab Emirates, where they recently arrived for training missions. The limit on flight distances, however, means the routine mission of patrolling U.S. airspace in Alaska will be done by other aircraft, officials said. The Panetta order is an unusual intervention at the highest level of the Pentagon in a service-specific problem, and it may be seen by some -- including critics of the F-22 program on Capitol Hill -- as a sign of the program's political vulnerability. The Air Force acknowledged last week that some of its aviators are refusing to fly the radar-evading F-22 Raptor, whose pilots in some cases have complained about oxygen-deficit problems which have caused dizziness, blackouts and other symptoms that arise when the body doesn't receive enough oxygen. The Air Force has been unable to determine the root cause of the problem. Panetta's chief spokesman, George Little, told reporters that Panetta supports the Air Force's efforts to get to the bottom of the problem. "However, the safety of our pilots remains his first and foremost concern," Little said. Therefore, in addition to those measures already taken by the Air Force to mitigate risks to our pilots, he is directing the Air Force to take three additional measures. Panetta ordered an acceleration of an existing Air Force effort to install an automatic backup oxygen system in every F-22; directed that all F-22 flights remain "within the proximity of potential landing locations" so that they can land quickly in the event they encounter a physiological problem in the cockpit; and he told the Air Force to provide him with a monthly report on progress toward finding the root cause of the problem.