USAF Lockheed Martin F-22 Raptors based at JB Langley-Eustis in Virginia and JB Elmendorf-Richardson in Alaska have been cleared to return to the air after a four day grounding.
The aircraft were grounded on October 21 after a pilot experienced hypoxia-like symptoms on a recent flight. The issue is the same as that which forced a four month grounding of the entire USAF fleet from May to September, and which remains unresolved.
