Over at the Danger Room, David Axe is making noise about the USAF’s official investigation into the loss of an F-22A Raptor and its pilot up in Alaska in November 2010:
When an F-22 Raptor malfunctioned in mid-flight, leading to a crash that killed its pilot, the Air Force went into damage-control mode. Gen. Norton Schwartz, the chief of staff, insisted there was no way that the oxygen generator on his prized stealth jet — a system widely suspected of being dangerously flawed — caused the crash. And even now that an internal inquiry seems to contradict Schwartz, the Air Force is still blaming (the mishap pilot) for the crash that cost (him) his life.
The most important discovery in the Air Force’s official report on the Nov. 10, 2010 accident in Alaska: The oxygen system in (the) F-22 failed in mid flight. Haney was running out of air. And yet the report concludes the crash was Haney’s fault, not the plane’s.
I plead guilty to actually having followed the link (pdf), and I think David is off base here. Despite the fact that the OBOGS system onboard the F-22 has proven to be at least potentially responsible for a number of mishaps and near-mishaps, the sequence of events in this particular event indicates a controlled shutdown of the environmental system (ECS) following an engine bleed air warning. The interesting thing about jet engines is that they’re always on fire, but the truly fascinating bit is where the fire is located. A bleed air warning means that fire – or fiercely hot gasses, at any rate – are mucking about where they ought not be. The OBOGS and cabin pressurization system – both necessary to sustain useful O2 uptakes at altitude the mishap pilot was flying – are a part of the associated ECS. They didn’t fail. They were – considering the bleed air warning – purposefully, albeit automatically, shut down.
At OBOGS shutdown, the mishap pilot’s mask was not receiving oxygen. The two choices he had were to activate the emergency oxygen system, and/or remove his mask while doing so. His time of useful consciousness would not have been great with the cabin depressurized, but neither would he have instantly lost consciousness. Contributing factors to the mishap pilot’s failure to activate the EOS were probably his winter weather gear and NVDs, and perhaps the location of the EOS actuation ring.
But any pilot’s first responsibility in extremis is to “maintain aircraft control.” The mishap pilot was coming down from high altitude at a very high rate of descent, and at one point – possibly while straining to activate the EOS – he actually went inverted. At night. In a single-seat fighter. And was sufficiently conscious to execute a sadly delayed dive recovery from an unusual attitude just prior to impact.
I hold no brief for the USAF mishap investigation team, and I’m withholding judgement on the Raptor’s OBOGS implementation. That said, while it’s no doubt tempting to put this particular mishap at the feet of some monstrous military/industrial complex golem, the facts and sequence of events as listed in the mishap report just don’t support that theory.
Sometimes bad things happen.
Lefty Defense gadflys always see the “Complex” at work. The loss of Capt. Jeffrey Haney is a tragedy. You’re right Lex, board must look at every angle. Sadly the “press” will twist this to “prove” that the F-22 is flawed.
There was no cry of a coverup when the wings fell off an F-15 a few years ago. Nope, no aging fleet here. Just a blurb and not even a mention in Wired.
Both Air Force and Army have a distinct tendency to automatically blame the pilot if things go bad. I agree that the pilot has the duty to first “fly the airplane.” There is too much of a tendency to get distracted by other things and lose sight of where you need to keep the sky relative to the ground in the cockpit.
The question I have deals with the pilots mental ability as his brain is starved of oxygen. The lights don’t have to go out before you are disabled to the point of being unable to act rationally. We know that it doesn’t take much oxygen deprivation to read that point either. And, as with so many things, people have varying levels of tolerance to such situations.
Another factor. If the cockpit depressurized at 30K+ feet is onset of bends. Bends can be very disabling, not to mention distracting as it can be quite painful. Many don’t consider this possibility, but Henry’s Law affects Pilots just as does Divers. Brooks AFB used to have the only decompression chamber in Texas, and although divers used it, it was kept around because pilots were subject to pressure diseases just as divers were, particularly back in the days of unpressurized cockpits. Half the atmosphere is below 18,000′.
Looking at the timeline, Bends could have become an issue just before impact if the cockpit did depressurize. The acts of the pilot, however, tells me the biggest issue for the pilot was hypoxia and his fogged brain killed him.
Your second paragraph is where I immediately went. I know that in one of the mishaps… the pilot doesn’t remember anything. I don’t even think he remembers landing. That blew me away when I read that. Is training so great that the subconscious kicks in or is it as you stated… that some people’s tolerance is far greater than others? Perhaps a combination.
Back in the day when I was in Lex’s first adversary squadron, there was a tape that was “funny” to listen to. A four-ship of adversaries was turning to engage. “One’s in.” Two’s in. Thresssssssiinnnnnnnnnnnnnnnn, fading out, followed quickly by “Knock it off.” Pilot recovered full consciousness, had no recollection whatsoever of what happened, only the tape convinced him.
The AAF didn’t know the facts about hypoxia in the 30s. LeMay, in his autobiography, told of flying to Latin America and taking occasional puffs of O2 from an oxygen bottle when he would feel a bit light headed.
By WW2 they had learned and had started issuing oxygen masks. Bad things could still happen. A formation of P-38s over the North Sea lost one of their number when suddenly the AC dove for the drink. They were at 30,000 or so feet when the incident and it had all the hallmarks of a pilot passed from lack of O2.
In my reading one guy stated the 8th AF placed an emphasis on close shaving before a mission to improve Oxygen mask sealing to the face.
The mental acuity effects from hypoxia are real and dangerous, as you’ve described. I had a pilot under my control in a test squadron who went hypoxic. Here, hypoxia was assessed by his flying a difficult data collection profile, and repeatedly missing the data points at a moderate altitude of 20-25k. This would not have been noticed had he not already flown that profile on a prior mission and nailed the data points. This mission terminated early (successfully), and on the ground, the pilot saw his error. It had been his procedure (corrected by this incident) not to plug in his O2 hose until he took no. 1 on the runway. This time, he’d forgotten to plug in.
Eric Hines
There is of course the question of having an 02 generator which shuts down in an engine casualty, and then making shifting to the 02 bottle backup a pilot initiated event, rather than making shutdown of the former and cutting in the latter simultaneous and automatic. You could cue a backup alarm and light if the the bottle didn’t automatically cut in, and put the @%&^* manual start button where you could bang on it and initiate manual start quickly while wearing the maximum amount of personal kit for the worst environment possible on the planet.
Or so it seems to me knowing nothing about design and operation of AF airplanes.
Sometimes stuff happens, find out why, and then figure out what to do to keep it from happening again. Or so I think.
Concur. Having the OBOGS shut down automatically is understandable, but the backup should be kicking in automatically.
I’d bet money the test team raised the issue fifteen years ago…and the program managers and LM refused to do anything about it.
Agreed. The entire chain of “aviate, navigate, communicate” is predicated on respirate.
I worked on the simulators for the F-22. There’s lots of room in the cockpit (it’s as roomy as my living room), and lots of empty space on the right console for stuff to be added. Another neat feature, discovered while the simulator was being developed (certainly the design specs said to ape the cockpit in every respect), was a parking brake switch to be used when the aircraft was being towed by maintenance–after towing, the maintainer in the cockpit could flip this switch and the parking brake would be set, without needing to power up the aircraft. The switch was on the back of the console in that empty real estate, where a pilot might toss his stuff as he mounts up. Initially, this switch was unguarded and the “brake on” position was to the outboard side. Just where the switch would be knocked on being hit by the tossed stuff.
Eric Hines
Perhaps, since these birds cost just shy of a train load of dollar bills, we as taxpayers should expect that either some automatic work around to this situation had been incorporated into the system or the AF put pilots in the AC who had been thoroughly trained to deal with it. Either way, to blame only the guy who paid the ultimate price for his alleged error, the designers apparent error, and the pilot training/selecting system for its possible error stinks.
Whew. The pilot has an overheat, his oxygen is automatically cut off. It’s dark, he’s moving fast. Has to (while wearing a bulky flight suit and clunky big night vision goggles) reach to his left, low and behind his position, to pull a ring to breath again. I can sit here at the laptop and attempt those same actions and my right hand and leg push forward and away from me as a natural reaction. Already in a right wing down/nose down attitude, the act of the pilot reaching for air to breathe put the aircraft further into an unrecoverable dive.
Sad. Has to be a redesign of some sort here. The backup system should be automatic, as Grandpa and Mike M. have stated. At the least, put an oxygen backup system switch right in front of the pilot. The OBOGS may not be flawed,
but the system as a whole isn’t quite complete. As was my sentence…
Did you hit the emergency O2 button?
The system is more flawed then you realize. (You does not equal Lex. He knows the system.) There isn’t anything tied into the system logic-wise that indicates there is no O2 getting to the pilot. Only at the end, when there is a big hole, and you pull the black box can you see ‘oh, he didn’t have O2′. A pilot can be flying and be getting contaminated air or intermittently be getting no air, and a fault isn’t tripped anywhere. It’s a stand alone system that doesn’t report to anything.
And I understand what the accident report says and I understand your opinion, Lex, I do, but I don’t think this falls into that category. I think this falls into system flaw and a young man died and I STILL think he died needlessly. Busbob and QM made good points as well as Grandpa and Mike M. Unless someone finds a suicide note in this young man’s belongings, you’ll never hear me utter the words it was his fault.
I’m stunned that the normal mode failure shuts off your oxygen. I guess someone decided that hypoxia wouldn’t sneak up on you that way. Bou, as I read the report, flow stops to the mask, causing a feeling of suffocation. Are you saying the system provides unpressurized air? Having been in the altitude chamber many years ago, I don’t recall any discomfort going hypoxic due to “thin air”.
I do understand the reports conclusions. That doesn’t mean there aren’t system issues as well.
Lex, if you have some extra time one day, how about a write up on the trials and tribulations of NVG ops in single seat fighters. I’ve got about 150 NVG hours as a Blackhawk crewchief now, and even a simple thing like strapping in is a chore with them. Something about having your eyes out on 6 inch stalks combined with tunnel vision. We rely on a _lot_ of crew coordination when goggled. How much time is spent doing emergency procedures under goggles? ( I assume in the simulator!)
They were still pretty new when I was leaving the cockpit. and there wasn’t much “crew coordination” apart from a reminder “goggles, goggles” prior to a deliberate ejection. The thinking being that that weight forward of your spinal column could break your neck when the seat fired.
Ours were designed so that you could see “under” the goggles for in cockpit tasks like handling an EP. Don’t recall that I ever did any simulator EPs. One of the good things about the Hornet – as you’ll see if you watch today’s airshow demo – is that she’s pretty low maintenance on the flight controls. So long, of course, as the flight control system is not the source of your emergency.
They were nice to fly with on a good night with the proper lumens. I always sorta sighed when I took them off, especially behind the ship. You had to give your eyes a good 15 minutes to re-adjust, and even then it was always dark “down there.”
I don’t know what the system is providing, since that part is not my system, nor where the flow stops. But I do know that sometimes someone not receiving O2 could also mean that he’s getting something, just not O2. There could be contaminated air.
In what I’ve read, I never read that the pilot experienced a period of suffocation before the incident. When the guy augered in, bark in the wheels and scratches in the intake, I didn’t read that he felt like he was suffocating. But I read… that he doesn’t remember.
I also have heard, this has not been duplicated.
Good articles about hypoxia in current APPROACH magazine PDF (2.2Mb) http://www.public.navy.mil/navsafecen/Documents/media/approach/App_Nov-Dec11.pdf
Beat me to that cite ! ! Indeed interesting reading: OBOGS degrade/failures, Bleed air fails, can’t pull the green ring, can’t find the green ring, didn’t manually turn off O2, other issues/reasons. Seems the systems are working as designed; however, to this former avionics designer: perhaps that design needs to be refined/revisited/revised. Something just ain’t quite right.
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