From: Alan Cairns 

On 31/12/03 1:46 PM, in article 3ff34104{at}w3.nls.net, "Tony Ingenoso"
 wrote:

> At 30-40K feet where the long distance flights fly its very cold and the air
> is very thin.   I've been to 16K without oxygen for a
> few minutes in a jump plane as it climbed and prepared to make a jump run.
> You start to feel the effects rapidly once over 12-13K.
> The general guideline is oxygen is required for any significant length of
time
> if you're going over 10K


The point is precisely that you don't feel the effect. I got depressurized
to 30,000 feet at an RAF training camp. We sat in the chamber and wrote out
a passage. Meanwhile, we were depressurized. I felt nothing, no warning
that things were going badly. My writing had deteriorated rapidly, and
ended up as a line across the paper where I had passed out. But I had no
idea I was about to.

Alan

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