Pressure Vests Not Cure-All to F-22 Oxygen Problems

Air Force and Navy engineers might not have solved the riddle after all to what’s causing F-22 pilots to suffocate when flying the vaunted fifth generation fighter jet.

F-22 pilots stopped wearing pressure vests in June after it was discovered the vests that prevent pilots from blacking out chronically failed and restricted the pilots’ breathing. Air Force officials claimed to not have any documented cases of hypoxia since ditching the vests that maintain blood flow during the high-G maneuvers the pilots perform.

The Air Force thought it finally had found the “root cause” that had long escaped the Air Force’s investigative team.

That is until the Air Force agreed to escort Elisabeth Bumiller of the New York Times to Joint Base Langley-Eustis, Va., to watch F-22 operations. Bumiller writes in this morning’s story that she witnessed a pilot pull the emergency oxygen handle.

“But last week, as Air Force officials escorted a reporter and a photographer to the Langley flight line to watch F-22s roaring on and off the runway for an ostensible good-news story, it happened again. A pilot pulled his emergency oxygen handle sometime after landing because of what the Air Force characterized as “discomfort” from intermittent air flow into the pilot’s mask during flight. The Air Force is investigating but so far has said little.”

The oxygen issues have stumped the Air Force for almost two years now. An issue that sort of flew under the radar while Congress and the media were distracted by the problems with the F-35’s development, two F-22 pilots brought the oxygen problems out into the national spotlight with their appearance on 60 Minutes.

Air Force leaders have intermittently grounded the F-22 fleet as they have explored the problems and restricted the distance pilots can fly from base and the altitude the fighters reach. Defense Secretary Leon Panetta has instructed the Air Force not to fly F-22s more than a 30-minute flight away from base and pilots must stay under a 44,000 foot ceiling.

This has not kept the Air Force from deploying an F-22 squadron, which it did in April when it sent the fighters to United Arab Emirates’ Al Dafra Air Base. Capt. Phil Ventura, an Air Force spokesman, declined back in April that the deployment was a threat to Iran as many speculated.

“Such deployments strengthen military-to-military relationships, promote sovereign and regional security, improve combined tactical air operations and enhance interoperability of forces, equipment and procedures,” Ventura said.

Engineers and scientists will go back to the drawing board it appears as the pressure to find the “root cause” increases. Senator Mark Warner told the New York Times that he’s been “pressing” the Air Force “about the explanation for this, and we still don’t have an answer.”

Do the inspectors go back and re-examine the F-22’s On-board Oxygen Generation System and questions still loom when the service can install an automatic backup oxygen system to protect pilots. A team of doctors and engineers remain on call to collect data after any pilot feels light headed after an F-22 flight. The question is: When will it lead to answers and save the F-22 from itself?

About the Author

Michael Hoffman
Michael Hoffman is the executive editor at Tandem NSI and a contributor to He can be reached at
  • blight_

    Get some F-22 parts, heat them in an oven and vent the gases into a cage full of rabbits, gerbils, guinea pigs or model organism of choice. Assess for hypoxia. Perform necropsy after sacking.

    • mi96romeo

      The manufacturer knows what chemicals are used to manufacture the parts, coatings, adhesives, etc. etc. We don’t need to slaughter animals we can heat parts and collect air samples and analyze these with any number of laboratory gear such as a GC-MS or FID, TOF-MS, and HPLC hypenated technique…….

      • blight_

        Previuosly I’ve thought about going straight for purge and trap and Gas Chromatography techniques, or maybe even headspace gas chromatography coupled to a FID as you suggest. Plus mass-spec for definitive identification.

        There’s a time and a place for in vivo models to assess physiology, not just presence/absence/quantity of certain analytes. Assessing offgas using analytical chemistry techniques is the first step if they haven’t tried it already: and if they still have problems, perhaps it’s time to look for new volatiles and high-temp byproducts which aren’t known in the literature and test them in vivo.

        • Dfens

          I believe it is about time to start the propaganda about the F-22 pilots all being crazy. That was both Boeing and Lockheed’s solution to the breathing problems workers were having when laying up composite parts for the B-2 and F-22. After all, airplanes are important. People are replaceable. At least, that’s the way it is in the inverse world of the US Air Force.

          • blight_


            Which mentions global composites. And when you go to the vendor’s page:

            “We have experience in designing and producing materials and/or parts for Military and Defense Applications:

            Acoustic signature reduction materials
            Electromagnetic signature reduction materials”

            Latter sounds like RAM to me. That said, OSHA is probably aware of worker safety issues, but has elected to issue pathetic fines.

            That said, you can outsource the health problems to the guys at Global Composites, and just stick the RAM onto your aircraft.

      • prairiewinds

        has any one checked the supplied chips that china has sliped n from r supply folks

  • leeretarmy

    I can’t help but wonder if this doesn’t have something to do with all of the reliable Chinese parts we are using in or tech heavy equipment.

    • blight_

      -22’s prototyped and rolled off the line before the PRC occupied our supply chain.

      • Brian

        China has been in the supply chain since the 90’s

        • blight_

          The peace dividend!

  • usmc

    just a thought here. as the old saying goes to much of a good thing is a bad thing. could the obogs be generating to much oxygen therefore leading to oxygen poisening?

    • blight_

      Other way around. They’re calling it hypoxia (lack of oxygen).

      • OldA4Guy

        Too much of a good thing is not the case with oxygen. I flew jets for over 20 years, and breathed 100% oxygen from a liquid oxygen tank the whole time (what we used to do before OBOGS was invented). Never had a problem. I’m wondering if the same problem happens with other OBOGS jets, like the FA-18 or AV-8B.

        • Jim

          OldA4Guy….Had you breathed oxygen from a lox tank the whole time for over 20years (or even just while you were flying) you would not have been on pure 100% oxygen. As an E&E guy… not sure the Navy equivalent… I can tell you the O2 regulators in the jets are designed to ‘mix’ your O2 with normal air. The concentration you breath is not 100% under ‘normal’ conditions. When the diluter lever is placed in “normal” as it should be under normal conditions the air is mixed.with ambient air below FL320 (could vary between airframes) Above FL 320 the ambient air port closes on the regulator automatically and it’s 100%.. Other than that it’s not 100% below that FL and ‘shouldn’t’ be placed there unless a certain condition requires it. It’s detrimental to your health to breath 100% O2 for extended periods of time and can cause death.

    • Navyair

      Oxygen only becomes too toxic under pressure, not lack of pressure. IE a scuba diver encounters oxygen toxicity at approximately 2 atmospheres or 66 feet. In aircraft, pressure lessens as you go up.

      As the old A4 guy points out, thousands of Navy and Marine aviators use straight oxygen from LOX (liquid oxygen) bottles every day. Unlike USAF (which uses straight 02 only for emergencies) the Navy/Marines use straight 02 from engine start to shut down because they never could come up with a diluter demand (mixes 02 with ambient air) regulator that would seal up effectively if the aircraft ended up in the water.

      OBOGS has been a great system. One of the other articles suggests that there may be an outgassing problem from the glues used in the low observable materials that is causing these problems. Quite obviously, if you are injecting a poison into the 02 system, it is gonna cause problems for the pilots.

  • mpower6428

    i thought all the smart kids went to the airforce….

    • Ben

      It’s not just the Air Force. Nobody can figure it out.

      • Juuso

        Pierre Sprey thinks that problem might be stealth coating of the F-22. I wonder if there has been any research about long term health effects, wouldn’t be too suprised if F-22 pilots have risk of getting lung cancer.

        • Ben

          Yes, with the exception of Sprey’s speculation. I’m honestly inclined to believe that may be the problem, however just as he pointed out, the USAF is likely turning a blind eye to it simply because a fix would be too costly. That being said, we may never know if Sprey is right.

        • William C.

          Problem with Sprey is that he is quite… say “motivated” against the F-22 and stealth aircraft in general. If he had his way the USAF would be flying F-16s without anything more than an IRST system and range-only radar.

          • Tyree Mitchell

            Kind of like BlackTailDefense(Mike Sparks) who is against most of the modern armored vehicles… and if he were in charge of the Army we would be riding in Gavins as APCs, IFVs, and tanks.

          • Jason

            Stop using the term Gavin, it only reinforces the myth someone other than Sparks uses it

    • WRG01

      I suspect you’re just being funny. Ok, I’ll bite….In response to your quip, I must point out that USAF personnel are smart enough not to have enlisted in one of the other services. (Disclaimer: Former soldier and a former airmen…served as NCO in both services).

      • mpower6428

        i was being funny or rather, trying to be. did it work?

  • Rod

    Interesting that the intermittent air flow into the pilot’s mask was during flight, but he didn’t pull the emergency oxygen handle until after landing. Can anyone shed some light as to why he would wait?

    • blight_

      Perhaps the fear of multi-tasking and possibly flying into the terrain, like the Elmendorf pilot.

      Pilot probably decided he was close enough to attempt a landing and landed early out of an abundance of caution.

    • Rod

      Thanks blight.

      If the air the pilot is breathing is drawn externally from the atmosphere, it would be before the combustion process, and is therefore unlikely that the problem is from the exhaust.

      Since the ground crew experienced similar symptoms, it makes sense to say it’s the aircraft’s coating that caused the problem because the coating is in front of the intake and within the proximity of where the ground crew would be working.
      The problem with this conclusion is that why can’t they detect it when the aircraft is sitting in the hangar?

      I wonder if the coating is being volatized by thermodynamic changes experienced in flight (ie pressure, temperature changes) and continues to behave like so for a short period of time after. If that is the case, it would explain why the hypoxia like symptoms being reported are so isolated in time but not space. It would also explain why he still felt the need to pull the handle after landing (which a faulty compressor wouldn’t at standard temperatures and pressures).

      Just applying another scientific discipline to a field I know nothing about. Take it easy on flaming my $0.02.

      • James

        Can you email a General? This sounds like the kind of good plausible logic people should listen to.

        • Rod

          I tried to but it never reached them. After extensive investigation by Gmail, it was determined that it was due to user error.

    • adam

      assuming your talking about the 60 min story. watch that segment again, and the effects of hypoxia. he knew he needed pull the emergincy handle, but he could not remember ware it was. could not remember. hypoxia can be some scarry stuff.

  • Mark

    rod don’t no if it has something to do with the way it is pulled To manually activate the oxygen system, pilots are required to first pull the green ring up and out of its slot, before pulling it directly towards them. According to the Air Force, this action can be the equivalent of pulling a 40lb weight, or more. maybe he did not feel the effects until he landed

    • Tom

      Most bailout bottles pull at 15-25 lbs. Granted I only see them on a bench, and have never pulled one while under G’s. Unless they drastically changed the mechanics of an F-22 bottle, I couldn’t imagine it would be much more than that. 40lbs seems a bit much to be pulling one handed while trying to fly a plane.

  • 4FingerOfBouron

    Probably needs 12 volts instead of 9 volts. Typographical error in assembly manual.

  • Uranium238

    In the end, they should just invent some high-G space suit and incoporate LOx. Whether the coatings are toxic or not, at least the pilot would be protected from both the altitude and chemicals.

    • blight_

      A redesign of the F-22s for LOX would set the program back considerably.

      As noted by others, OBOGS systems are in use in other aircraft. The question is whether or not OBOGS cannot perform in the same performance envelope as the F-22, or if it is the RAM coating, or as Sprey thought the glues to hold RAM (epoxide epoxy?)

      Would it be possible to have a RAM-less F-22?

      • Ben

        Taking away the F-22’s RAM is like cutting off it’s strong arm. You’d essentially have 186 insanely expensive, super maneuverable F-15’s. I just don’t see how you’d be able to justify the cost anymore.

        • blight_

          Depends. I imagine only Lockheed knows how much of the stealth is attributed to shape and how much to the RAM.

          • Dfens

            The F-22 more than the F-35 depends primarily on shape stealth, and not so much on coatings. It would actually considerably increase the mission availability of the F-22 to get rid of the coatings. That said, it is really not fast enough to survive very long without coatings. The F-23 would have been, but that’s water under the bridge now. The F-35 would be nothing without the coatings. Even so, I doubt it is the coatings alone causing these breathing problems. Outgassing from the composite parts themselves is known to cause breathing issues.

      • Matt

        Set the program back from what exactly? There are no future upgrades or goals for the platform as far as the eye can see. The USAF has effectively abandoned this plane.

      • adam

        if i remember right, the reason jets switch to OBOGS from LOX, was that LOX has a limited amount of O2, as OBOGS does not. with air to air refuling you can run out of air, also i think OBOGS is a smaller, lighter system, thou i never worked on it myself as I’m an electrician. as for the RAMless 22, that would kill a lot of the stealth, not all, and i cant say what % as stealth is from SHAPE, and materials. As OBOGS feeds from the engines, or the intake, cant remember wich, youd only have to take the RAM away from the intakes. problem is with that, is most of the stealth from the intake area is from the RAM, not RAS. (Radar Absorbing Structure or Shape) so, could you? yes, question is, what are you willing to pay for it, and is the epoxy the real problem? take a couple test modle 22s and fly them for a month straight with no RAM in the intaks?

  • JackBlack

    So tinfoil hats didn’t help?

  • Tad

    Really, nothing to worry about, it’s merely “discomfort”, according to the AF.

  • Lance

    Easy fix to this. Modify the F-15s oxygen system to the F-22 and NO Chinese made parts!

  • McPosterdoor

    Why did the pilot have his oxygen on while landing… at sea level @ Langley?

    • Chops

      I would imagine the discomfort was a bit more than he wanted to admit to the reporter.

    • Sir Sapo

      You wear your mask regularly on the ground, even before engine start…

  • Chops

    So with the oxygen being conditioned engine bleed air, I wonder if it couldn’t be a engine coating or wiring coating causing the problem when it reaches a certain temperature?

    • PlaneGuyB1B

      Jet aircraft have been using engine bleed air to pressurize cabins for years. There is always the possibility of contamination, but the technology is proven.

  • Chuck

    The problem now is how do you differentiate a real problem from the nocebo effect (same thing as placebo effect, except you use “nocebo” when it is a detrimental effect)? In other words, there may be (or may have been) a real problem with the oxygen system. But even if they have fixed it (or fix it in the future), pilots are going to be a little paranoid and tend to think any unusual feeling is from lack of oxygen.

  • Howe


    I bet the the USAF is wishing they would have chosen the (better) YF-23 now…
    So I think, unless Lockheed comes up with an amazing aircraft…the AF wouldn’t give them the next fighter contract, if nothing else, simply because they can’t fix the overpriced raptor.

    • HoweFan

      It’s all political

    • James

      Do you work at Embry Riddle?

    • Dfens

      It’s funny how everyone forgets that the F-23 was the MD entry into the ATF competition, though it was not designed by anyone at MD. They had to contract out the design. In fact, that was why the Phantom Works was started.

  • paperpushermj

    Just curious … Do the Chinese have the same problem?

    • Ben

      That’s trying to compare apples to oranges.

      • B.E. McCormick

        Mandarin oranges?

      • hellbound1339

        Why not, they’re still fruit. ;P
        More seriously, the Chinese wouldn’t say if they did, and this problem isn’t due to the Chinese parts.

  • B.E. McCormick

    Did some moron just choose to forget that we had ground crew problems around this puppy when the engines were running also? Or were they just “hoping” we would forget and buy into the pretend solution.

  • citanon

    It seems to me the intermittent air-flow during that flight is a separate and different problem from the hypoxia.

    In case of the hypoxia symptoms, the issue was not that airflow was interrupted, but that the pilots experienced hypoxia anyways.

    I do agree that an automatic backup system might be a good idea at this point.

  • Rob Damon

    Don’t pilots in other high altitude planes (SR-71,U-2,X-15) wear what amounts to a full space suite?? And these things are flying at 60-70K altitudes.

    How about converting one or two the F-22’s to accommodate a pilot in a “David Clark S1030 gold suit” and run around the clock ops and see what happens?

  • mpower6428

    this problem will be solved in january 2013, right after christmas bonus’s come in.

  • Politically Correct

    Why not just replace the OBOGS with Liquid lox converters? Obviously the current oxygen system is worthless and broken. How often do you hear of pilots in aircraft with lox converters getting hypoxia.

    • Dfens

      Even if you did that, the pilot does not breathe 100% O2 while flying. He’d still be breathing mostly bleed air siphoned off the engine compressor whose O2 content was supplemented by the LOX. In my opinion they need a separate dedicated intake for the environmental system with it’s own compressor.

  • nchie

    May the F22 stealth coating is much tha it coats the oxigen. I guess Russians can assist. Swallow tour pride and call for help

    • William C.

      You type like your suffering from hypoxia.

    • blight_

      I’ll coat your oxygen atoms with…smaller atoms!

  • Zhongnanhai

    This is a joke.

  • Rob

    B2 and F117s have the same prob?

  • dockem

    30 minutes from a base?????? Geee, no in flight refueling, no combat or escort duties. GREAT plane!! Let’s more money. Contractors love it!!

  • traindodger

    I read an article a while back that said that they’d found burned polyalphaolefin in the pilots’ bloodstreams. The power supplies for the avionics on this bird are cooled with liquid polyalphaolefin. Put two and two together, and there you go.

    • B.E. McCormick

      And that would explain the problem with the ground crews also.

      I just don’t understand why they would point to such a red herring that does not fit the known facts instead of making up a more plausible lie. It is too obviously wrong, so it has to be intentional. I would hate to think our people are that stooopid.

  • aaron

    This is my theory…and just a theory.

    The obogs system used on the raptor is probably driven by a accessory drive off the engine turbine, taking in intake air for obogs as well as some stealth coating that is used in the airplanes weeping skin. or possibly some kind of chemicle from the engine components. The obogs intakes the stealth coating and the prolonged exposure to this is exacerbated by descending back down to altitude forcing these chemicals into the blood stream leading to some other type of hypoxia besides hypoxia hypoxia or possibly a new kind of physiological condition altogether.

    on a side not I remember reading about some groom lake employees who suffered from illnesses when working on have blue.

  • Geoff.

    Hi All,
    Why can’t they have continued using the F-15 Oxygen system after all the F-22 is just a pumped version of that aircraft when getting down to basics ?


    • P&Wjjg

      The F-15 has zero in common with the F-22 In materials, manufacturing and performance. The young buck can fight at over 70,000′ while the elder fights at up to 60,000′.

  • TomUK

    Can’t anyone spell or punctuate any more ?

  • Matt

    Durrr… we fixed it with this here carbon canister… see?

    Wait, no! Wait…

    Durrr we fixed it with this magic vest, see?


  • Gunnie

    Hate to think that the F-35 might use the same systems ? What’s the bet ?

  • hellbound1339

    Seriously, does anyone have ANY MORE info??? It’s a little sketchy here…

  • DeeJay

    Instead of selecting the American OBOGS supplier, Lockheed selected a British vendor. The US vendor’s OBOGS has been used successfully in the T-45, AV-8B, F-15, F-16, and F-18 jets and several more since the 1980’s. Could false pride of ownership prevent trying the US system?

  • kittyhawk

    Why not have the manufacturer send in the designer, engineer, etc to see if the product we got is the system they designed? Have them check the computer system/program which controls it - Are the materials used, standing up to the flight conditions?
    Remember the mars flight that missed the planet because someone fed in kilometers rather than miles to the program? Why not put in a sensor system to measure airflow to see if oxygen is being supplied as needed at all times?
    For want of a nail…..

  • PlaneGuyB1B

    How about temporarily fitting pilots with bio-sensors that measure and record vital information, such as heartbeat, blood pressure… BLOOD OXYGEN LEVEL. When a “hypoxia” incident happens, download the bio-sensor to see if it is hypoxia… or something else.

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