AF Still Reviewing Oxygen Levels for F-22 Cockpit

The U.S. Air Force will continue to investigate the oxygen concentration levels in F-22 Raptor cockpits in the wake of reports about fluctuations of those numbers noted during studies of recent pilot breathing problems.

“We also will study and as necessary revise the schedule by which the Obogs (On-Board Oxygen Generation System) adjusts the oxygen concentration delivered to the pilot to better mitigate against the identified effects of too low or too high a concentration,” says service spokesman Lt. Col. Edward Sholtis.

Oxygen concentration level fluctuations were noted in the Air Force Scientific Advisory Board (SAB) Report on Aircraft Oxygen Generation, which delved into the recent Raptor pilot breathing problems and was released last month.

“As the aircraft descends and the pilot puts eight Gs on the aircraft, the percentage of oxygen produced by the Obogs is reduced,” the report says. “As the pilot reduces the G load, the Obogs begins to recover and then the percentage of oxygen produced by the Obogs is reduced again when the pilot reapplies the Gs.”

The report says, “The amount of oxygen being produced does decrease to between 60 percent and 70 percent.”

A software “deep dive” is under way, the report says, as well as a further assessment of the reasons for the drop in oxygen concentration noted under G-loads.

By design, the Obogs oxygen level for the F-22 is lower by five or six percentage points than levels required for earlier-type fighters, and the SAB report says there is “limited understanding of the aviation physiology implications of accepting a maximum 93-94 percent oxygen level instead of the 99+ percent previously required.”

The report says, “Given the F-22’s unique operational envelope, there is insufficient feedback to the pilot about the partial pressure of oxygen in the breathing air,” adding there is “no indication of pilot oxygen saturation throughout the F-22 flight envelope.”

The report also cautions that “ECS (environmental control system) shutdowns are more frequent than expected and result in Obogs shutdown and cessation of breathing air to the pilot.”

Noting “some anomalies in the performance of the F-22 oxygen and anti-G delivery systems when the ECS cuts back or shuts down in-flight, or during the onset of High-G forces,” the report says the incidents “merit further analysis and testing.”

Obogs efficiency is key for flight operations, the report says. “Unlike most other aircraft oxygen generation systems, the breathing air to the F-22 pilot is not diluted with cockpit air to obtain the appropriate oxygen partial pressure (PPO2) necessary to maintain physiological function at a particular altitude, but rather it is concentrated to the necessary PPO2 by controlling the cycling of the Obogs.”

- This aticle first appeared in Aerospace Daily & Defense Report.

- By Michael Fabey


  • Anonymous

    But but I thought it was the pilot’s fault?

    • Kole

      I know right!

    • Mastro

      Stupid pilots can’t grab handle (when their blood oxygen levels flatline)

    • Steve

      it was , he got on the damn thing didnt he ? -then it must be the pilots error (in judgment)

  • BlackOwl18E

    Ground them. Dissect them. Find the problem. Until they find the problem the F-22 shouldn’t be active.

  • HeavyArrow

    Or install a system that works. Take the F-15’s system, and use it in the F-22.

    • Lance

      word up

  • wait-whut?

    wait, I thought it was the g-suit…..

    • Nick

      They’ve forgotten the most important part of lying, which is to always tell the same lie.

  • Lance

    Seems the USAF covered up crappy production of F-22s and faulty systems more than just fix the problem.Overall installing F-15 oxygen and some avionics packages to the F-22 can fix the problem.

    As well as saving billions by scrapping lightweight fighter ie F-16 and F-35 all together and go for a all heavy fighter force of F-22s and soon upgraded F-15Cs with new AESA radars and new computers.

    The RAF did similar in 1940 with the new Spitfire (like the F-22) and Hawker Hurricane (like F-15C) both did air superiority and the Hurricane also was a interceptor. It worked superbly for the Battles for Britain, North Africa, and lasted till the end of the war fine till jet fighter came.

    We should invest in new strategy and upgrades rather than a light fighter which does crap.

    • Mastro

      I don’t get the Spitfire comparison at all- the Spit was absolutely a lightweight fighter- based on a racer.

  • Rational Rob

    You just need an air superiority fighter to clear the skies. Longer ranges on Radars and AA missiles will win future wars. It doesn’t have to be an F-22.

    Light fight attack aircraft that are slow and can deliver munitions to the battlefield are a perfect alternative for the A-10.

    As for SEAD/DEAD, just use drones.

  • Ron

    Until this plane kicks butt in the skies—it’s still CRAPTOR

  • wolfvines

    G-Suit and Oxygen. Come on.This plane is bad ass. NEVER GIVE UP. #^&*$$$ fix it.

  • Big-Dean

    God almighty, is there not one “man” left in leadership position in any service? AirForce, Navy, Army? (The Marine Corp is not quite castrated yet but they are turning in PC pussies like everyone else).

    Someone needs to step up and simply say to Congress “yes, we’ve know about this problem since the beginning and I take full responsibility for not being forthright and honest and I offer to turn in my commission if you wish me too. If not, then I will uncover the veil on the problem and tell you what’s going on and what the plan is for fixing it within the next six months or I promise that I will retire even if it asked not to.”

    Our leaders, in all services, need to man up and quit acting like the service is simply just a stepping stone to the corporate boardroom job.

  • Sonny S Sulit

    Help fast!all over the world’s