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Another airliner crashes.

This is your Captain Speaking…

Another airliner crash, this time in Greece with a Cypriot company. All aboard are lost, with a report that one of the passengers emailed his cousin that the pilots had passed out and they were about to die. A tragic story, made all the worse in that it could have been prevented.

The reason that pilots are so interested in crashes is the fact that all of us think, “There but for the grace of God, goes me.” We look for mistakes of the pilots or maintenance problems, anything that can be identified as a specific cause. We want to know so that it doesn’t happen to us, or if it does, what we can do in the cockpit to change the ultimate end of the incident. When all is said and done with this accident, there will be a cause that may tell us how to change things so it doesn’t happen again. Here is my initial outlook cause, and my recommendation on how to fix the problem.

The jet lost pressurization; the pilots became unconscious; and the jet, operating on autopilot, flew into a mountain. The first is a maintenance problem; this jet had a history of pressurization problems. It needed to be fixed, normally it is not that hard to isolate this kind of problem and clear it. Sometimes it is something that cannot be easily be fixed and you just have to fly with the problem as a possibility on every flight. It can be done; maintenance histories are available to the pilot on every sortie. Just be aware, and take proper preflight procedures to insure that the oxygen system is working, so this sort of thing does not end in a tragedy.

The second problem. The loss of pressurization in a modern jet (One of the pictures I saw was of a 737-700 or -800, the most modern examples of Boeing’s stable) should in no way cause the pilots to lose consciousness. Two possible problems: The pilots did not put on their oxygen masks, or they did not work when they did put them on. It is easy for the un- or undertrained pilot not to recognize the symptoms of hypoxia, which is the loss of oxygen to the brain. Everyone is different, and in the American Armed Services, every pilot who flies in an airplane capable of flying so high that hypoxia could be a problem undergoes training in a depressurization chamber every 3 years. That way they can recognize their personal symptoms and be prepared to go oxygen if they feel any of them. The other problem is complacency. A routine preflight will include checking the oxygen system, which always works. But checking the oxygen system involves putting your face into a clingy rubber mask that smells bad, and you never know who licked it last. Unpleasant, at best, and the system always works. People have been known to abbreviate the check. But, properly done, it shows that the system not only works but also is turned on, that the maintenance switch down below the cockpit has not been turned off in order to work on the O2 system itself.

I wonder what the investigation will tell us. What it will not say is that these pilots had been in a depressurization chamber lately, unless they were in the military. Civilian pilots are not required to do that. Did the O2 system work? It worked in the cabin; the masks were deployed. How high were they when the pressurization problem occurred? It makes a difference; the higher you are the less time you have to get on O2. If they were high, then the reaction is instantaneous, a lower altitude may not give the pilots the sense of urgency they would need to get on the O2 immediately. (That happened to me once. A story for another time.) Right now there are only questions.

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2 Responses

  1. Rereading the post, I noticed I had not made my recommendation. It is a simple, but expensive thing to make each airline pilot who flies jets to go through an altitude chamber, also called a hypobaric chamber. This would allow them to suffer hypoxia and learn their own individual symptoms, as well as show them that is imperative to get on the O2 as rapidly as possible. The altitude chamber “flight” entails trying to do a simple task while in an hypoxic state, and it sure gets hard to subtract 3 from 91 when your brain no longer works.

    Another thing. The loss of pressurization on an aircraft is no reason to lose the jet. I have lost pressurization twice while in the Air Force (well, three times). At United when I was there we lost pressurization one time that I recall, and there could have been more. It is a fairly routine emergency procedure, but it is one that cannot be put off while you are doing something else. At the normal altitudes we fly in current jets, the loss of pressurization gives the pilots between 35 to 60 seconds to get on O2, a simple task. But at least one pilot has to get on it in time; if they do not you will lose the jet.

    I was amazed that the loss of Payne Stewart in a bizjet caused no increase in the training within our pilot population. (His death was caused by pressurization failure.) Ex-military pilots have undergone this training, but at least half of our airline pilots come from a civilian background, and they have never been in a hypobaric chamber. It is time they all get the chance to do that.

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