Correction: An earlier version of this article incorrectly said that the Air Force has 188 F-22 Raptors. It has 187. The article also incorrectly said that the Air Force had deployed F-22s to the Middle East for the first time this spring. In fact, some of the aircraft participated in a training exercise there in 2009. This version has been corrected.
Defense Secretary Leon E. Panetta ordered the Air Force on Tuesday to curtail flights of its F-22 Raptor fighter jet and accelerate the installation of backup oxygen generators in response to pilot complaints of wooziness and fainting spells in the cockpit.
Panetta’s intervention was spurred by the public refusal of some F-22 pilots to fly the aircraft despite the insistence of Air Force leaders that the radar-evading plane is safe. Some members of Congress have also expressed concerns that the Air Force has failed to take warnings from its pilots seriously enough.
In what amounts to a rebuke of the Air Force’s handling of the issue, Panetta directed that F-22 flights be limited in distance so pilots can easily make an emergency landing at any given time. He also told the Air Force to speed up its plans to add backup oxygen supplies to the aircraft and to report to him monthly about efforts to pinpoint the cause of the problems.
“The secretary wants to add his muscle to this,” George Little, the Pentagon press secretary, told reporters. “He takes very seriously the concerns raised by the pilots.” An Air Force spokesman declined to comment on Panetta’s directive.
The F-22, manufactured by Lockheed Martin, is considered the world’s most advanced fighter jet. It can fly at supersonic speeds and engage in air-to-air combat but also drop bombs on surface targets. The Air Force has 187 of the planes.
The aircraft entered military service in 2005 but has sat on the sideline during the wars in Afghanistan and Iraq. However, some F-22s participated in training exercises in the Middle East in 2009, and in April, the Air Force acknowledged that it had deployed some of the aircraft to the region, basing them in the United Arab Emirates.
The Air Force grounded the plane last year for five months after pilots reported cases of hypoxia, or symptoms resulting from a lack of oxygen, such as nausea and blackouts. Officials were unable to find the root cause of the problem, however, and returned the aircraft to duty in September.
Since then, Air Force commanders have said that they are continuing to investigate but that the aircraft is safe to fly.
On April 30, the head of the Air Combat Command at Joint Base Langley-Eustis, who oversees the F-22 and other fighter jet programs, told journalists that the risks of oxygen deficiency in the cockpit were small and manageable.
“Right now, we believe that risk — although it’s not as low as we would like it — is low enough to safely operate the airplane at the current tempo,” said the officer, Gen. Mike Hostage.
A week later, however, two F-22 pilots took the extraordinary step of appearing on CBS’s “60 Minutes” to declare that they were refusing to fly the aircraft because of oxygen deprivation in the cockpit.
One of them, Capt. Josh Wilson, a Virginia Air National Guard pilot based at Langley, said he suffered a severe case of hypoxia during a training flight in February 2011 and had to be treated afterward in a hyperbaric chamber.
The television appearances privately angered some Air Force officials, but commanders later acknowledged to Congress that they were legally required to grant military whistleblower status to the pilots and would not punish them for refusing to fly.