Air Force confident answer near in F-22 mystery

In this April 30, 2012, file photo, an Air Force F-22 Raptor displays it's weapons bays as it goes through maneuvers during a demonstration at Langley Air Force Base in Hampton, Va., Monday, April 30, 2012. / AP Photo/Steve Helber, File

(CBS/AP) WASHINGTON - The Air Force believes it is getting much closer to pinpointing the reason why pilots of its prized F-22 stealth fighters sometimes suffer an oxygen deficit during flight, a senior general said Thursday.

The problem prompted the Air Force to ground the aircraft for a period in 2011, and Defense Secretary Leon Panetta last month ordered new flight restrictions after CBS' "60 Minutes" program aired interviews with F-22 pilots who complained about the oxygen problem.

Maj. Gen. Charles Lyon, who is managing the Air Force's effort to resolve the mysterious problem, said in an Associated Press interview that it is likely that the pilots' symptoms are caused by previously unknown restrictions on their breathing.

"We're not ready to declare victory yet," he said, but this is the first time the Air Force has narrowed down the likely cause. Lyon said he also is close to ruling out another theory: That contaminants were getting into the pilot's lungs via the oxygen delivery system that is connected by hose to their flight helmets.

Is the Air Force's F-22 fighter jet making pilots sick?
The F-22 pilots who talked: Why they did it
Pentagon limits F-22 fighter flights

Lyon said he is satisfied, after extensive testing, that no harmful contaminants are moving through the oxygen system. He is the director of operations for Air Force Combat Command and has been leading the F-22 work since January.

Lyon said the root of the problem, which has caused some F-22 pilots to feel dizzy and experience other symptoms of hypoxia, or oxygen deprivation, may turn out to be linked to two issues:

CBS News correspondent David Martin reported that, according to the Air Force, there have been 22 unexplained cases over the past four years in which pilots experienced symptoms of oxygen deprivation.

Lyon said additional testing will be done before the Air Force can be certain that these restrictions are the root of the problem. (Watch full "60 Minutes" report at left.)

The Air Force has come under fire from some in Congress for not taking quicker action to fix the problem. Two leading critics, Sen. Mark Warner, D-Va., and Rep. Adam Kinzinger, R-Ill., told reporters Thursday they believe the Air Force needs to be more open with the public about the issue.

Warner and Kinzinger also said that information they received from the Air Force this week indicates that the oxygen-deficit problem is greater than the Air Force had previously believed.

New information also was released from a study done by Boeing on the issue and an internal survey of pilots, the majority of them who did not feel confident in the F-22's breathing system:

In the AP interview, Lyon acknowledged that there had been a higher rate of hypoxia-like incidents among F-22 pilots since the plane was returned to flight in September than in years past. He said there were 11 such incidents from September to March 8. But since then, over a period in which the F-22 has flown about 6,000 hours, there have been none, Lyon said.

"The trend line is very positive," the general said.

Lyon said he briefed senior Pentagon officials and congressional staff members this week, including the staffs of Warner and Kinzinger, on all aspects of his work to solve the F-22 problem.

The F-22, manufactured by Lockheed Martin, is the Air Force's most-prized stealth fighter. It was built to evade radar and is capable of flying at faster-than-sound speeds without using afterburners.

The 170-jet fleet is stationed at six U.S. bases: Joint Base Elmendorf-Richardson, Alaska: Joint Base Pearl Harbor-Hickam, Hawaii; Joint Base Langley-Eustis, Va.; Nellis Air Force Base, Nev.; Holloman Air Force Base, N.M.; and Tyndall Air Force Base, Fla.

F-22 pilots are trained at Tyndall. Flight testing is at Edwards Air force Base, Calif., and operational testing and tactics development is performed at Nellis.

[highiron999]

John782011 The pressure vest is not a flight suit that squeezes the extremities to keep blood in the head during sharp turns. It is used IF cabin pressure is lost SUDDENLY, like the canopy gets blown off at HIGH altitude. The pressure in the pilots lungs is much higher than the sudden new low cabin pressure. To stop the pilots lungs from being damaged or bursting, the vest applies instant pressure to hold everything in place while the now excess air leaves the lungs.

[John782011]

Thank You for the explination. That makes a lot of sense. Was a submariner so we did not worry about excessive over inflation unless we were doing a free assent as part of an escape at deep depths.

[nancy_naive]

The plane has an operational envelope that would turn a man into a pizza; the pilot is the limiting factor.

Time to stop letting the egos of a handful of men drive the costs up and the efficacy down.

[raymailhot]

You are correct. The F22 is the limit of what a person can take. But at the same time we don't have unmanned capabilities close to this amazing plane. So a new suit is in the making.

[John782011]

Used to be that G-Suits were to contain the blood from going to the extremities in high G maneuvers. I have never heard that the compression on the pilot at high altitude would improve their oxygen intake efficiency. Could someone help me out here?

[nancy_naive]

Should have just continued the F-15/16 lines.

F-22 and F-35 are colossal wastes of money and effort.

[KansasCity-2012]

It is extremely difficult to believe that the Air Force, who has built many high performance aircraft for decades, suddenly discovers a problem of this type. The F-16 uncovered blackout due to excessive G's and resolved this with a combination of reclining the pilot back and installing a software package that detected a dead control stick input and a diving condition that would take over the plane and discontinue the deadly dive. Oxygen delivery has been around since WW-II. High performance is newer.

I think the Air Force needs to look more into pilot pre-blackout research from physical distress of acrobat flying.