Friday, September 02, 2005

Ask the Pilot....Or Not!

Salon has a regular weekly feature called "Ask the Pilot" (may be subscription only). It's written by a real airline pilot by the name of Patrick Smith, and is quite interesting and informative...particularly for we plane sluts. Anyway, I ran across this particular question and thought it might be, in a morbid kind of way, a change of pace from the consistent awfulness that is New Orleans:
After the Helios Airways disaster in Greece, your article about the facts and fallacies of in-flight decompression included the following: "The time of useful consciousness after a full decompression at 37,000 feet can be less than 10 seconds." Why so short a time? Sitting here, even without inhaling first, I can hold my breath for a good 60 seconds with no danger of passing out, as can most people. Why should it be any different in an airplane?

At sea level, where the ambient pressure is about 14 pounds per square inch, a typical breath of air has enough oxygen to last you a minute or more (your body is still getting oxygen from your lungs). At 37,000 feet, or about half that ambient pressure, a rapid or explosive decompression results in all air exiting your lungs -- sucked out by the resulting vacuum -- leaving you, nearly instantaneously, only with the oxygen in your bloodstream. That's not enough to sustain you for very long. Time of useful consciousness will vary with individual physiology, but will always be a matter of seconds. Trying to hold your breath in this situation, not that you'd be able to, would be deadly, bringing on an embolic explosion of your lungs.

Interestingly, a sudden high-altitude decompression not only pulls the wind out of your lungs, but also -- and this is personally confirmed by somebody who experienced one -- out of your bowels.

Scary, and perhaps disgusting as well, but remember these descriptions pertain to the worst case. As pointed out in the original column, the vast majority of pressurization snafus aren't nearly as severe.
Why do I always run into this type of information just before I'm about to fly?


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