Sen. Mark R. Warner said Monday he wants an immediate briefing on the F-22 Raptor and called on the Air Force to avoid penalizing the two Virginia-based pilots who have gone public with their concerns.

His comments, relayed through a spokesman, came in response to Sunday's "60 Minutes" segment that featured two Raptor pilots from the Virginia Air National Guard based at Langley Air Force Base.

The pilots, both veterans of the 2003 Iraq War, said they were uncomfortable flying the aircraft because of an oxygen-supply problem in the cockpit. In at least 11 incidents since September, pilots have reported hypoxia-like symptoms that have no single root cause – at least none that investigators have yet found.

"We want better answers," said spokesman Kevin Hall. He said Warner wants a personal briefing this week.

Rep. Rob Wittman, R-Westmoreland, issued a statement: "We need to take the necessary actions to ensure the F-22s are safe for our pilots to fly and continue to be viable asset of our nation's air power."

Sen. Jim Webb's office had no comment on the report.

Last week, Rep. Randy Forbes, R-Chesapeake, said he did not discount the pilots' concerns, but stressed that the Raptor's speed and stealth would be needed as the U.S. military shifts its attention to the Asia/Pacific region. Forbes chairs the Readiness Subcommittee on the House Armed Services panel, and frequently points to the rising military power in China as a need for the U.S. to maintain a technological edge.

The problem, Air Force leaders say, is either a lack of oxygen in the cockpit or oxygen tainted with toxins. A probe had focused on the Raptor's oxygen-generating system, but it has since expanded to include an exhaustive look at the entire plane plus the pilots involved in the 11 incidents.

The Air Force grounded its Raptor fleet for four months last year while it investigated the problem. The jet was returned to flight in September even though no root cause was found.

Air Force leaders said that the risk of flying – while they wish it were lower – is considered acceptable, and that flying represents an inherent risk. Meanwhile, they continue to gather data and investigate.

Maj. Jeremy Gordon and Capt. Josh Wilson told "60 Minutes" they wanted to fly the aircraft, and its capabilities were superior. But the lack of oxygen causes disorientation and can sneak up without warning. They declined to say whether the F-22 should be grounded again. Gordon said he wanted to see the problem fixed and a root cause identified.

Wilson said there has been the "threat of reprisals." Warner, who did not see the news segment but was briefed on it, said, "there can't be reprisals against these pilots," according to Hall.

The two pilots spoke in the presence of Rep. Adam Kinzinger, R-Ill. A federal whistleblower law allows active-duty service members to come forward and talk with a member of Congress about serious concerns.

.In November 2010, Capt. Jeff Haney was killed when a malfunction in his Raptor's oxygen system caused him to experience a sensation similar to suffocation, Air Force investigators have said. That crash, while a tragedy mourned throughout the Air Force community, avoided massive losses because Haney crashed in the Alaskan wilderness, not a populated urban center like Hampton Roads.

In a video published by "60 Minutes" to supplement its Sunday segment, Maj. Jeremy Gordon talked about the consequences of a crash closer to home.

"We fly right over where my kids go to school – where my house is," he said. "A pilot not fully in his wits comes back and loses control or hits another aircraft . . . that's my family's biggest fear."