Hmm, I disagree, seems to be particular to the OBOGS in the F-22's design. Millions of safe flight hours with OBOGS on many other aircraft. I can't imagine the A-10, B-1, B-2, F-15E, F-16, T-6 investigations finding similar results, or at least not with the result of going back to LOX. What about the Harriers, Super Hornets... same standard, same manufacturer, but the navy is not jumping on this, right? Similar systems in the Rafale, Eurofighter, Gripen, Mirage2000, L159, by other manufacturers. I understand it's more complicated for fighters than airliners, and not sure if it's engine bleed air as you say in those cases, so I won't mention all the other planes that no longer need LOX servicing. My point is that it's far from just looking great on paper, it has already been proven.