The fighter jet fleet in which the Pentagon has staked its future is equipped with a "very different" oxygen system than the one that has plagued the F-22, its Lockheed Martin sibling.
After at least 12 cases where F-22 Raptor pilots reported losing consciousness, Defense Secretary Leon Panetta last week slapped flight restrictions on the Air Force's prized fighter amid concerns it is safe in all circumstances.
Panetta limited the distances the Air Force's F-22s can fly during a single mission, while also ordering a fleet-wide installation of an automatic backup oxygen system.
Lockheed officials have at times touted commonality between the F-22 and the F-35, which is being developed by the company for the Air Force, Navy and Marines, as well as some of Washington's closest allies.
So when the F-22 oxygen system flaws led Panetta to step in, there were whispers in defense circles that the F-35 might be prone to spawning the same pilot wooziness.
Lockheed Martin responded to DOTMIL after multiple requests for comment, sounding a confident tone.
"They are different systems," Lockheed spokesman Michael Rein says. "The F-35 and F-22 have common aircraft oxygen system suppliers but the systems are very different...The two systems each utilize a similar approach and architecture, but they are packaged and implemented differently.
"The F-35 program continuously monitors issues present in other aircraft assessing applicability to our current design," Rein says. "The program has leveraged the lessons learned from F-22 development to enhance the F-35 across all subsystems, including the Onboard Oxygen Generating System."
Loren Thompson, a defense analyst at the Lexington Institute and an industry consultant says the F-22 oxygen system flaw likely will not show up across the F-35 fleet.
"The F-35 is not aircraft, but three built for three services and three distinct missions," Thompson says. "That means if there are some carry over issues for the Air Force version of the F-35, it might not carry over to the Navy and Marine variants," he says.
Teal Group tactical aviation expert Aboulafia says the super-fast F-22 might be more prone to the oxygen issue than its slower sibling. "The F-22 system might be more vulnerable," he says, due to the aircraft's "faster speeds and higher-altitude capability."
John T. Bennett covers national security and foreign policy for U.S. News & World Report. You can contact him at email@example.com or follow him on Twitter.