No Fly Zone -- Update

Update:  The grounding of the F-35 test force has been lifted. A procedure for monitoring the valve in the integrated powerpack (IPP) has been approved, allowing test aircraft to continue flying before the USAF Safety Investigation Board completes its report.

But the F-22 grounding is well into its fourth month, and the investigation of possible problems with its onboard oxygen generation system (OBOGS) will continue into the fall, according to a new USAF release.

There is no specific word on when a return to flight could take place, although the USAF's Scientific Advisory Board will be releasing interim reports as the investigation continues.

"The zero-risk solution is not to fly, and that's not a long-term option; it's an inherently dangerous business to fly and fight wars," according to Lt Col Matthew Zuber, SAB executive director. "We want to make sure we mitigate risks to a level that's appropriate for the urgency of the mission." The F-22 force has not been flying to its full envelope since January, when a 25,000-foot altitude limit was imposed.

However, so far, the investigation has not determined whether it is a lack of oxygen, the presence of contaminants such as carbon monoxide, or other factors that is causing F-22 pilots to experience hypoxia-like symptoms at three times the rate of pilots on other aircraft. Zuber says that no possibilities have been eliminated.

On the F-35:  Production aircraft remain grounded and restricted from IPP and engine running on the ground until a permanent fix is found. This will affect pre-delivery testing at Fort Worth as well as the two aircraft already delivered to Eglin AFB. It is understood that the fix is likely to involve both hardware and software and there is no firm date for implementation as yet.

Tags: ar99, f-22, jsf, tacair