Military limits F-22 flights after oxygen issues

The military is taking new measures as it tries to determine the root cause of possible oxygen-supply problems in the F-22 fighter jet.

Secretary of Defense Leon Panetta has mandated that all F-22 flights "remain within the proximity of potential landing locations" to ensure the ability to recover and land should a pilot run into "unanticipated physiological conditions," Pentagon spokesman George Little said on Tuesday.

In addition, the Air Force is speeding up the installation of an automatic backup oxygen system in all the fighters, Little also announced a Pentagon press conference.

Panetta also has requested a monthly progress report about the service's progress in finding the cause of the oxygen problems on the fighter jets.

The Air Force has been looking into a number of reports that pilots experienced "hypoxia-like symptoms" aboard F-22s since April 2008. Hypoxia is oxygen deficiency.

Even more mysterious, the Air Force has also been looking into a number of reports that mechanics have been getting sick as well.

The fleet was grounded in May 2011 so the service could check the hypoxia reports, but the order was lifted in September under a "return to fly" plan, with equipment modifications and new rules including daily inspections of the life-support systems.

Since then, five mechanics have reported hypoxia symptoms, according Gen. Daniel Wyman, command surgeon for the Air Combat Command.

The plane's manufacturer, Lockheed Martin, has started an online campaign to combat the negative publicity.

Here's more about the new measures from the Pentagon briefing:

QUESTION: George, on that topic, did the secretary consider grounding the aircraft again? And also, does this restriction on proximity of a landing site affect the deployment of the F-22s that are in the Middle East at the moment?

PENTAGON SPOKESMAN GEORGE LITTLE: The secretary believes that this is the prudent course of action to take at this time. As I indicated, he will be receiving regular updates, and all options remain on the table going forward.

In terms of the deployment in Southwest Asia, we believe that we can safely continue that deployment, given the geography of the region.

QUESTION: Why not just ground the fleet until you know what's causing the oxygen problem?

PENTAGON SPOKESMAN CAPT. JOHN KIRBY: Well, I think George said it well. The secretary believes this is the prudent course right now. It allows us to continue to examine the aircraft closely and to try to figure out what happened.

There's a trouble-shooting process that's going on right now. So the aircraft being in operation assists in that process. We believe we've mitigated the risks as much as possible.

And, again, safety of flight's paramount. The secretary's going to continue to get updates and if he has to make future decisions about the fleet, he'll do that. But right now he believes and he has - and he has been briefed very recently on this, very deeply on it, he believes that this is the right course right now.

QUESTION: Can I follow on that?

KIRBY: Sure.

QUESTION: The two "60" - the two pilots who flew the F-22 that were interviewed on "60 Minutes" addressed that issue about how the Air Force needs - says it needs to take, you know, tests from flights in the air to figure out what the problem is. They described themselves as guinea pigs.

How do you ensure that, you know, airmen who are flying the Raptor aren't being used as guinea pigs in this case.

KIRBY: I don't think we would ever refer to a fighter pilot in the United States Air Force as a guinea pig.

They are highly trained, highly skilled. We value their service and their expertise. And, frankly, that service and expertise is critical to helping us figure out what the problem is here.

QUESTION: On that same topic, this quick recovery issue, how - what is - how far can they fly, essentially, under that new guideline? You said that they don't do any long-duration flights, so what's their limitation now?

KIRBY: I believe it's situational more than anything. I don't - I don't believe there's a nautical-mile limit here. It's just about an appropriate level of proximity to strips so that if they needed to get down in an emergency, they could in a relatively easy, quick fashion.

But I don't - there hasn't been a - there's not a mile radius put on this.

QUESTION: So - so it's about proximity to strips in Alaska, let's say, so they have to be aware of landing strips there lengthy enough to accommodate their landing.

KIRBY: Well, certainly the strips have got to be - they have to be capable of handling that type of air - aircraft, absolutely. But it's about just general proximity here.

QUESTION: Is it indefinite until the problem is solved? And what about if (inaudible)