By Larry Shaughnessy
CNN

Even as the Air Force searches for the reason pilots are getting sick flying the F-22, a new mystery about the troubled stealth fighter jet has come to light: Why are mechanics on the ground getting sick in the plane as well?

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.

The Air Force reports 25 cases of such systems, including 11 since September, when the service cleared the F-22 fleet to return to flight after a four-month grounding.

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.

"Early on in the return to fly we had five maintainers that reported hypoxia symptoms," Gen. Daniel Wyman, command surgeon for the Air Combat Command, said during a conference call with reporters Wednesday.

The maintainers are mechanics on the F-22's ground crews who sometimes have to be in the cockpit while the jet's engine is doing a ground run.

"The maintainers, when they are doing their ground run, are not on the mask, they are in the cockpit," Wyman said.

The problem with maintainers getting sick while on the ground throws a wrench into some of the theories about why at least 25 pilots have suffered hypoxia symptoms.

The Air Force experts trying to figure out the cause of the problem have pointed out that the F-22 flies higher and faster than its predecessors, the F-15 and F-16.

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Read more here: http://security.blogs.cnn.com/2012/05/09/mystery-of-f-22-illnesses-grows/?hpt=hp_t2

What makes the F22? Lockheed Martin.

Interesting story blue please keep us updated on any developments