After six years and 46 planes, the F-22 Raptor program at Langley is complete. One of the last of the pricey, single-seat Air Force fighter jets to roll off Lockheed Martin's production line arrived in Virginia on Friday.
But top brass at the Hampton base, home to the service's Air Combat Command and two Raptor squadrons, aren't really celebrating the milestone. They're too busy trying to figure out why some F-22 pilots aren't getting enough oxygen in the cockpit.
"We're leaving no stone unturned," said Maj. Gen. Charles Lyon, who is leading a team of dozens of experts examining possible causes of "hypoxia-like" symptoms among Raptor pilots.
The Air Force grounded its entire fleet of about 180 Raptors last May after a spike in the number of pilots reporting problems during flights. Hypoxia occurs when the body doesn't get enough oxygen, resulting in dizziness and altitude sickness, or in severe cases, death.
In November 2010, Capt. Jeff Haney died in a crash during a training mission in Alaska. A malfunction caused the plane's oxygen system to shut off, and Haney wasn't able to start a back-up system before losing control of the $147 million plane.
No Raptors flew for almost five months. After extensive research did not pinpoint a cause, the Air Force began lifting flight restrictions in September.
During 12,000 sorties and 15,000 hours of flight since then, there have been 11 instances of unexplained hypoxia, Lyon said.
Researchers have moved away from focusing on the aircraft or a piece of equipment as a cause. They're now following two theories - that something toxic in the cockpit air is interfering with a pilot's oxygen absorption, or that, for certain people, a combination of gravity forces at certain altitudes could be to blame.
Since ending the "stand-down" in September, the Air Force now requires every F-22 pilot to fly with a pulse oximeter strapped to a finger, measuring oxygen saturation in the blood. If it dips below a certain level during training missions, pilots are required to return to base.
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