TOKYO (AP) -- The deployment of a dozen F-22 stealth fighters to Japan has so far gone off without a hitch as the aircraft are being brought back into the skies in their first overseas mission since restrictions were imposed over incidents involving pilots getting dizzy and disoriented, a senior U.S. Air Force commander told the Associated Press on Thursday.
The six-month mission is a key test for the fighters, which have been the focus of intensive investigations over potentially deadly breathing problems in the cockpit.
Following more than a dozen incidents in which pilots said they were having symptoms suggesting they were not getting enough oxygen, and a fatal crash in 2010 that has since been ruled primarily a case of pilot error, the F-22 fleet was grounded for several months last year. It was put under restrictions again in May after two pilots came forward with claims that the aircraft weren't safe to fly.
Brig. Gen. Matthew Molloy, commander of the 18th Wing at Kadena Air Base on the island of Okinawa, said there have been no incidents with the F-22s since they arrived in Japan late last month, just days after U.S. Defense Secretary Leon Panetta announced he was easing the restrictions. The planes have been flying almost daily since then, weather permitting.
"We won't ever bury anything if there are issues, but so far, none," Molloy, who is also an F-22 pilot, told The AP in a telephone interview. "It's delivering safely."
In giving the green light to send the stealth fighters to Okinawa, the Air Force said it had identified the main problem as a faulty valve in its "Combat Edge" flight vest and said it was taking a series of measures to ensure pilot safety. The measures should be complete by the end of the year.
In the meantime, the pilots in Japan are operating under altitude ceilings so they do not need to use flight vests. They are also on a "tether," meaning they must remain close to an emergency landing site.
"The Air Force has been aggressively looking at this very complex issue," Molloy said. "I'm glad that we are getting back on the road."
Some critics have questioned the Air Force's decision to deploy the F-22s to Japan before all of the life support fixes have been finished.
The choice of Okinawa is also sensitive because of an uproar over plans by the Marines to deploy their MV-22 Osprey at another base there as early as next month. Despite reassurances from Washington, opposition to the Osprey, which can take off and land like a helicopter but fly like an airplane, is strong on Okinawa because of two recent crashes elsewhere.
Molloy said he is "100 percent" confident that the F-22s are safe to fly. He said sending them to Japan was justified because they boost U.S. capabilities in a key region and reassure U.S. allies of Washington's commitment to them.
"I think this is very much appreciated by Japan," Molloy said. "It strengthens our alliance, it shows that we are very committed."
The problems with the F-22 have been particularly troubling for the Air Force because the fighter is in many ways its showcase aircraft — and possibly its most controversial.
The F-22, manufactured by Lockheed Martin Corp., can evade radar and fly at faster-than-sound speeds without using afterburners, capabilities unmatched by any other nation. But at $190 million apiece, not counting development costs, it was lambasted in Congress as an overpriced luxury item not suited to current conflicts. Its production was halted last spring and the aircraft has never been used in combat.
Nevertheless, Molloy said the Japan deployment shows that the F-22 remains an important part of the U.S. air arsenal because it gives the Air Force the capability to get into contested areas against adversaries that have better air defenses than countries like Iraq or Afghanistan.
"It's a game-changer. It does air superiority on steroids," he said. "It's a strategic gem, a national treasure."