F-22 Raptor Fleet Grounded Indefinitely

So the F-22 Raptor fleet has been grounded by Air Combat Command boss Gen. Robert Fraser due to problems with the aircraft’s oxygen generating system, the same flaw that has kept the jets restricted to flights under 25,000 feet since January. The system has been under investigation since shortly after the late November crash of an F-22 in Alaska. The total grounding was apparently due to numerous reports of pilots suffering from a lack of oxygen while flying the jet since the restriction was put in place. It should be noted that at 25,000 feet its almost impossible for an unacclimatized person to breathe normally. Capping flights at that altitude would theoretically allow a pilot to more quickly dive to a lower altitude where he could breathe without the oxygen system’s help. The jets have been gounded indefinitely until the problem is solved, according to numerous reports.  If they’ve been looking at this since November, it has to be a pretty tricky problem. You can also be sure that speculation will emerge that problems with the oxygen generator system played a role in the Air Force’s much-discussed decision to keep the F-22s out of the fight in Libya.

While the Air Force says it could scramble F-22 crews in case of an emergency that warrants the need for the jets, pilots will train on simulators until the restriction is lifted.

  • Strange

    told you you should have gone with YF-23

    • Not so Strange

      The YF-23 would have the same issues. OBOGS is a new development in an effort to remove the volatile liquid oxygen bottles from the aircraft. The technology is currently used on other platforms including the F-18 and E-2D. It has growing pains like anything else… the real culprit is the DOD hurrying these technologies into fleet use before they have all the bugs worked out.

      • Derrick

        Very true which is also why the F-18’s are also grounded aswell. But for some reason that parts not being published

    • JD1031

      The USAF pilots all wanted the YF-23. It was political, Lockheed had better lobbyists greasing the politicians bank accounts. The rule was to have a flying proto-type by a certain date, McDonnell/Northrup team had two, none for Lockheed so they pushed the date. See the result.

    • Entropy.

      Kind of reminds me of my verdict on the F-20 vs the F-16, though this time the reasons come in spades.

  • theman

    For such a sophisticated aircraft, I find it surprising that one of the most basic necessities does not work. Does anyone know exactly how the oxygen “generator” works on a Raptor?

    • Cunninglinguine

      Sodium chlorate, barium peroxied, and potassium perchlorate. Mix carefully. Oxygen is produced, but the reaction is exothermic and the chemistry container gets pretty hot.

      • asdf

        for how long is the reaction sustained? in the passenger ac it’s only for about 15min i think.

      • mike j

        No, that’s a chemical oxygen generator. The OBOGS is the military version of the portable breathing machine you’d give a patient with respiratory failure. “Pressure Swing Adsorption” is the technical name, zeolite in a matrix ‘soaks up’ the nitrogen.

    • Max

      No joke. I may be wrong, but it sounds like a case of the military trying to Rube-Goldberg some new technology when the old tried-and-true tech (that would have been a lot cheaper too!) would have worked just fine. Haven’t we seen this before?

    • British bull dog

      Long live eurofighter typhoon half the price twice as reliable And just as effective !

      • passingby

        shouldn’t you say ” more effective “???

  • Anthony

    Grab one from an F-15 and stick it in? Or do they need to have a multi million dollar stealth oxygen system. I’m glad we can still use them for emergencies at leasts, such as alien invasion, or even less likely, an attack from china or russia. Better be fixed in time for the Great New England Air Show this summer! I’ve been waiting since 1999 to see one of these babys in action.

    PS also sad that at 8 Billion spent a month in Afghanistan we could afford 40 more F22s…a month

    • Anthony

      Was thinking more today…we should take a Billion away from Pakistan and restart our Raptor program, even 5 planes a year would put tens of thousands of engineers (young and old) back to work. Even better we can park a dozen of the newly-built ones in Afghanistan in case Pakistan decides to build a mansion for any other mass murderers!

      • Oblat

        Pakistan is asking for more money. Otherwise they will let us lose in Afghanistan.

  • TJ Jones

    OBOGS works just fine on the F-15E. Oh, I forgot, that’s a McDonald Douglas/Boeing product.

  • Navy guy

    Been in F18’s since early 90’s…

    • Raptor tech

      Ya but the F-18’s are also under investigation

    • Steve

      You should get out more.

  • Friend of OBOGS

    OBOGS was first flown in 1978, fielded in 1983. There are over 20 platforms using OBOGS. It’s far from new.

    Each application is unique, it’s critical to have experienced suppliers providing experienced support to insure such a major safety system is implemented correctly.

    Imagine the results from a poor fuel system, or fire control system supplier

    • Oblat

      The F-22 OBOGS was never tested. They just ran a simulation and assumed it was ok. If it wasn’t well that just meant a heat profit for the contractor so they didn’t care.

  • SJE

    Can someone explain why oxygen supply is better than just providing air at sea-level pressure

    • SJE

      I mean, you just have to pressurize the air from the outside. You can even oxygen enrich with filters (see latest Boeing commercial aircraft). No need for chemicals or bottled oxygen, unless you have concerns about chemical weapons.

    • asdf

      because you don’t always fly at the sea level.

      • SJE

        And the solution is to pressurize the air to that at sea level. We do it abord commercial airliners. In fact the F-22 already contains 2 existing air compressors: the turbojet engines.

      • SJE

        You need an OBOG when you are in space or in the ocean, where there is no air. Not so in the atmosphere.

        • swissfreek

          There’s a rule in the book that says that if you fly higher than 25000 feet you have to have supplemental oxygen. If you don’t, you can’t fly above 25000, pressurized or not. So if your OBOGS is out (or flaky), you’re stuck below 25000. AND if you’re above that and OBOGS goes out, there’s a rule on how fast you have to be able to get back below 25000, too. I can’t remember what the reason was for why 25000 is the magic number. I assume it has to do with partial pressures and your blood’s ability to retain oxygen at certain pressures or some such, but the Crew Systems guys are the ones who get paid to worry about stuff like that.

          On commercial jets, cabin altitude is generally about 8000 feet (though Boeing and Airbus are both bragging that their new jets can maintain 6000, saying it adds to passenger comfort). On military jets it’s usually higher than that. Fighters are generally required to maintain a cockpit pressure of 25000 feet (there’s that magic number again), up to their service ceiling. In some cases it’s actually a limiting factor: the altitude at which the cockpit can no longer maintain a 25000 foot pressure is the aircraft’s ceiling. The interesting thing is I remember being told that at least part of the reason the Raptor had an unusually high ceiling for a fighter was the fact that its cockpit could maintain that 25000 feet higher than the average jet. Go figure.

          • SJE

            Thanks, I did not realize that they operated the cockpit pressure so low. With the enhanced oxygen demands under stress, I can see why enriching the air makes sense.

          • JimBob

            The other reason you have to look at is that pressurizing the cabin of a fighter (and commercial aircraft as well, that’s why they use 8000 feet) to sea level puts more stress on the pressure vessel (the cabin) and means you would have to use heavier structure or materials to keep it from rupturing. All of which can be better used on weapons and fuel. In addition, consider that the Raptor operates higher than most commercial aircraft service ceilings (therefore increasing the pressure delta)–that is when its OBOGS is working.

        • Nadnerbus

          Pulling this out of my butt, but I’d assume it’s because, even in the old model, they only had to compress the oxygen and bottle it. Oxygen in dry air (no water vapor) is something like 21 percent. So You’d have to carry almost five times as much compressed air to accomplish your plan, or you can just carry oxygen to supplement what is already in the air at or above 25000 feet. And since that oxygen bottle would be highly flammable in the event of an accident, I can see why generating it chemically as needed would be more desirable.

          At least that seems to be the question you were asking.

          • Nadnerbus

            Never mind, that wasn’t your point.

    • Josh

      And commercial airliners arent pulling 9 Gs on a consistent basis. pressurized and enriched air is an essential part of keeping a proper level of oxygenated blood in the pilots brain so they dont GLOC and crash the aircraft/die. Fighter aircraft are extremely physically demanding.

  • ew-3

    See what happens when you have to have a pilot. Go UAV.

    /mostly sarc.

    • Thunder350

      /Mostly true.

      • Don’t Judge Me

        /Mostly Implausible

  • Belesari

    Yes and watch 10 40mil UCAV’s (which no one can build because dog fights are HARD) to one enemy fighter.

    UCAV’s are atleast 15-20 years away even then i cant see them doing more than hauling missiles.

    Besides trusting the skys to a computer when you may have to fight the biggest hacking army in the world is insane.

    This as in most things is way more complicated than it apears.

  • seeker6079

    I think that when the USAF comes in looking for the next jillions to produce the 6gen fighter every senator and congressman should wear a t-shirt that just says “$65b and it can’t even let the pilot breathe”.

    Useless, money-sucking bastards.

  • Go Supersonic

    Nice Fighter but far to expensive. I don’t think the US will ever have such a project again. Go UAV, I agree with ew-3. Better save and spend on the lousy infrastructure.

    • Stratege

      UCAVs/UAVs are not able to replace manned air superiority fighter jets in close times. Period.

  • Go Supersonic

    But the airshows will become boring in a couple of decades!

  • steve

    Space based weapons lasers etc. plus rebuild nasa into the number one agency. phuck ALL treaties. and the g-ddamned un

  • steve

    Space based weapons lasers etc. plus rebuild nasa into the number one agency. ***** ALL treaties. and the g-ddamned un



    Read more: https://www.defensetech.org/2011/05/06/f-22-fleet-grou

    yes, censor. i said phock all treaties with All countries

    • Don’t Judge Me

      Obviously, your entire knowledge of warfare is based on Sci-Fi movies. As if laser Weapons are at all practical. A laser capable of causing damage from orbit would require a massive amount of power to operate. As for rebuilding NASA, it’s not that easy to redistribute funding. It takes major planning. Finish high school before making wild suggestions. America is not the Galactic Empire, Obama is not Darth Vader, and it is impossible to build a Death Star. Please consider how stupid you’re about to make yourself look before you submit a comment again. Thank You.

  • Oblat

    The F-22 is a failed design. Most of what the fan boys talk about is the brochure not the actual aircraft. Apart from the oxygen system and inability to fly above 25,000 feet. The communications system is broken, the software is bug ridden, there are structural flaws which have crippled the lifespan and the maintenance costs are going up not down as technicians learn more about how big a turkey the aircraft really is.

    Deliberately inadequate testing, poor project management and an emphasis on screwing the customer is the difference between the PR and the aircraft. It doesn’t matter how good the brochure makes the aircraft seem you cant go to war waving glossy brochures.

    • Tenn Slim

      Your comments are simply wrong.
      A failed design. Hardly. The F 22 is complex, tested, re designed multiple times, and is the best stealth actually in the field.
      I could count beans with you here, but to no avail. I was there, EMD phase and beyond, I know better.
      OBOGS is a liquid O2 generating system. Used extensively in all USAF Aircraft.
      Software may well be the current problem. A basic system, but the Raptor lives on computers. Nuff said.
      Semper FI

      • casual reader

        Tenn Slim

        The F-22 did not undergo thorough testing before entering production!! That’s commonly accepted among F-22 observers. The jet is complex, yes of course, but (and hence) ridden with unexpected problems and flaws.

        The “stealth coating” has problems. The software has problems (putting it mildly). The oxygen generating system, the communication system, the engines, the composite airframe, …

        Your claim about its stealth is highly suspect, considering how well the jets movements had been tracked by both the Chinese and the Russians over the course of their deployment in the Pacific.

  • Oblat

    The fighter mafias nostalgia for manned combat creates a huge opportunity for countries like China to leapfrog out capabilities. Air combat UCAVs are not only higher performance but can execute strategies that no manned aircraft would attempt because the pilots aren’t willing to take the risk.

    • Duuuuurrrrr

      You really have no idea what you are talking about do you?

  • Stratege

    Without A.I. (which still does not exist!) UCAVs can not adequately play any role of manned air superiority aircraft.

    • Don’t Judge Me

      Agreed. I can’t see AI ever replacing human pilots.

      • blight

        Why? Training is just a series of reinforced decision-making cycles. Developing AI is a software problem, not just a hardware one. If you’re trying to implement on old chips running off of Ada then expect to have issues.

  • Tenn Slim

    “Deliberately inadequate testing, poor project management and an emphasis on screwing the customer is the difference between the PR and the aircraft. It doesn’t matter how good the brochure makes the aircraft seem you cant go to war waving glossy brochures. ”
    Hardly a Tech Comment.
    Wrong on multiple counts.
    USAF folks were there EVERY step of the PDR, CDR and First Flight days.
    LM folks that built this aircraft are far better managed and employed than you indicate.
    A sorry post indeed.
    Semper FI

    • casual reader

      Sorry, but yours is hardly a tech comment by your own standard. Besides, deliberately inadequate testing involves nothing technical – it’s anything but technical. It may be political, commercial, financial, … but it’s not technical.

      USAF folks were there …??? How do you know? You were following them EVERY step of xxx, yyy, zzz?? Exactly what USAF folks means? pilots? engineers? administrators? clerical staff? secretaries? their boyfriends and girlfriends and kids and spouses? Where were they? Somewhere inside the building? Roof top? Parking lot? Swimming pool? The gyms? golf course? club lounge? or inside the labs? assembly lines? computer centers? these question would be a little bit more technical. Can you answer them in (technical) detail?

  • JimBob

    “at 25,000 feet its almost impossible for an unacclimatized person to breathe normally”

    While this is true, realize that the cockpit itself is pressurized to some altitude (typically 8000 ft MSL up to the mid 20’s and then a 5 psi delta between cockpit and ambient pressure above that. Obviously on an OBOGS-only equipped aircraft, the O2 portion of this pressurization would likely be compromised just like the mask supply.

    “played a role in the Air Force’s much-discussed decision to keep the F-22s out of the fight in Libya”

    The decision not to use F-22’s was most likely threat (or lack of) related. There is no need to use 5th generation fighters in a theater where the most robust air threats are Mirage F1, Mig-21 and Mig 23. This is especially true when you can have self-escort strikers that drop the bombs and clean up the air picture for themselves, or use F-15C’s to provide OCA.

  • JimBob

    EDIT: apparently “male rooster”-pit is edited out, so cockpit should read “cabin”

  • Storm1

    Oblat, the F-22 is an incredible piece of engineering period. The F-22 can fly like no other plane I’ve seen. There are always issues with highly technical/advanced aircraft. The Air Force/Navy/Marines have dominated the skies since the end of WWII. My nephew’s an aviation technician for the F-15E. Although, he still loves the F-15 platform, he’ll be the first to admit that the F-22 hands-down is the dominant aircraft. Obviously, you’ve never serviced in a branch of the United States military. Get your facts straight.

    • casual reader

      That’s sheer hype. “Air Force/Navy/Marines have dominated the skies since the end of WWII”????

      For a period during the Vietnam War, US jets were being floored by Soviet Migs or their Chinese variants in dogfights, to the tune of over 90% loss in dogfights. Their solution – run upon encountering enemy fighters and wait till they are low on fuel!!

      You might want to read it. Same for the Korean War.

      US jets are not as good as advertised. Same can be said about US pilots.

  • Don’t Judge Me

    I definitely agree with Storm1 and Tenn Slim. The F-22 is one of the best investments the US has made with its aircraft budget. I’d like to see Oblat come up with a better design than the Raptor. Just because it has some critical problems doesn’t mean anything about it’s worth, because ALL aircraft have problems at first. Give it some time.

    • passingby

      You have no basis to agree with them (idiots). This is NOT a matter of opinion. Facts are facts. And the facts are: the F-22 is colossally over-budget, over-hyped, seriously flawed, problem-ridden, and fatally dangerous to its pilots.

  • Павел

    The RFP was issued in 1985, first flight of the YF22 was 1990. The program is coming up fast on 30 years. As good a flier as the aircraft is it has been plagued with problems forever. 78 billion dollars is a lot on cash to spend on an aircraft that is reduced to flying training missions and patrols. Possibly a better option would have been to replace the F15/16/18 fleet with more of the same. Very capable aircraft and all that is needed.

  • OBOGS problem is fixable – but I would bet that we are not being told all the truth – F-22 is so stealthy that if it was flying over Libya a) we would not know b) they would not tell us.

    • passingby

      don’t hype something you don’t know, unless you get paid for it.

  • Qasrani

    Suppose if you have a PC or laptop which does not turn on or does not work properly when you switch it on, or when you want to play a game, or in the middle of game it breaks, how you feel about it? Or think of a gun when you are in face to face with your enemy. Suddenly your gun has A problem, no matter what, it does have a problem. If I need my weapon and I pay for it, I should have it working as and when needed.

    5th generation fighter jet is a weapon rather than a toy or mere gun. If you need one or more F-22 in the air to face a real challenge which can not be countered with any other available means, guess any single such fault can be fatal to not only aircraft or its pilot but TO THE DEFENCE OF A WHOLE NATION.

    Army and defence is not a thing to be played with. Either you are ready or not. That makes the difference when a real and urgent need arrives.

    I do not want to comment on F-22 as it is my favorite but when I see that a project costing over 65 Billion USD results in a fighter which is intended to be produced in mere figures of 187 total, don’t you think there might be something wrong? I accept everything about F-22 IS best available at this time, but when you can not count on it 100% when it will be able to work and what altitudes should be used to fly that plane and what possible problems might be facing it, I think it needs a bit better management than it has currently?

    PS: No offence meant to anyone!

  • joe manning

    Does anybody wonder why the oxygen system is now an issue and why this would be linked to crash in Alaska where “it just disappeared off radar”

    I want to know if it’s routine to send a pilot out on a solo training mission,and why they kept saying the F-22 only had one person aboard.
    They don’t make a two seater Raptor do they? Not putting down the military but I’m not buying the story I have much respect for the pilot that died in crash I just hope he was not sent on a one way mission if you know what I mean

    • Dhunter

      the f-22 only has the one version, a single seat aircraft. Pilots selected to fly and fight with this airframe are not being plunked in the seat straight off the street. Each has extensive flight time and training for the airframe.

      Sudden onset hypoxia incapacitates and then kills faster than the victim can understand what is going on. Payne Stewart and his entourage were all killed by this effect.

      the accident did not have the aircraft “just disappear”; it plunged from altitude and impacted the tundra in a near vertical attitude punching several meters into the muskeg.

  • iused2fly

    As of May 17th, 2011 there are parallel investigations taking place into the OBOGS systems in the A-10, F-16, F-35 and T-6 aircraft.” So a wide net is being cast to look for other problems with similar OBOGS installattions.

    Being around aviation for as long as I have, I expect an aircraft as complex as the F-22 to see some components than are less than fully robust. We all just have to wait until more information is available. Given the financial momentum of this very expensive program I expect the F-22 problem to be solved with a re-design and the F-22s back flying unrestricted some time late this year or early 2012.

    • F22 Pilot

      I fly an F22 and the advantage is amazing but I’ve had difficulty with the oxygen system as well

  • Rick

    As vezes é bom vcs verem que projetos caros nem sempre trazem beneficios a curto ou médio prazo, claro é sempre bom ter poderio bélico superior, mas as custas do povo de seu país que por muitas vezes nem sabem o que ocorre com o dinheiro publico que é gasto na defesa ! Existem forças ocultas por tras de tanto erro de projeto de um avião caríssimo desse ! Pensem nisso !

  • Robert R

    Typical Yanks. Spend billions on an aircraft that doesn’t work. OR is it all a big scam because they have something even more potent ( top secret flying out of Area 51)? Remember the Oxcart A-12 (CIA machine) versus the SR-71 (Air force version) and all the internal disputes. And, I wonder how the SR-71 replacement (Araura- or whatever) is performing??

  • stranger

    f22 is suck

  • truct

    as the USAF top brass have a consistant record of disregard for their pilots safety…and usually blame the pilots for any malfunction, the problem with the f22 must be serious, obviously too serious to sweep under the mat…its also serious for the defense of the west.

  • truct

    P.s. its no good saying…”.oh well any complicated kit is going to be troublesome ” when you have spent that much money,and bought so many f22 s, that excuse is an excuse and not a reason…..Someones head should roll.

  • Picard578

    F22 is made primarly as military-industrial complex’ money maker.

  • jake

    Bad thing is the OBOGS on all the aircraft has been tore apart so many times it’s not even funny they keep saying there is nothing wrong the current fix is a warning system to let the pilots know he is about ready to lose oxygen. The air force is not fixing the problem at all they can’t fix the problem. So pilots don’t lose their flying status they are not reporting the problem and going into hypoxia and trying to land and go on with life this is a fact. No one is even considering the extensive corrosion all over the jet. Come on stealth coatings are full of heavy metals some don’t go together very well. It’s going to be a huge cost to fix this it is the same for every aircraft in the air force fleet. All in all this aircraft is a waste of money its expensive to fix and the coatings has to cost a lot because you have to take them off just to get to the panel where the problem is. There are so many things being found out on a daily basis this jet should be put in the bone yard before more people die. If not from hypoxia from the chemicals on the aircraft itself.

  • F22 Pilot

    F22 Is really advanced in everything so why are they needing to sort the oxygen out?