"Danny Dot" wrote in message
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"Chris" wrote in message
...
snip


Upto 10,000 ft air only
10,000 - 33,700 ft Oxygen/air mix
33,700 - 40,000 ft 100% oxygen
40,000 + 100% Oxygen under pressure



I flew fighters for the Air Force (F-4E) and I recal going to pressure
breathing at about 25,000 feet cabin altitude. This was an emergency only
because the cabin pressure never got this high. I also recall a rule to
not go over 50,000 feet because of blood boiling (bends) IF the cabin
pressure was lost at greater than 50,000 feet.

Well the bends more commonly known as Decompression Sickness (DCS) is a
possibility from about 18,000 ft unpressurised and is caused by the nitrogen
in the blood coming out.

The received wisdom is that if you have been scuba diving and gone deeper
than 30 ft (ie breath under pressure) then flying should be avoided for 24
hours.

whilst we are on it, the 8 hour bottle to throttle rule is a bit of a
fallacy too. It depend of course on how much was drunk. The body only breaks
down about 15mg of alcohol an hour and if one has been eating heavy meal in
an attempt to hold back the alcohol then it can only put back the clock from
when the body starts the breakdown process. A big meal only slows down the
absorption of alcohol by the body, it has no effect on the breakdown.

I suspect that those pilots who have been busted recently either don't know
or don't care to know how alcohol works in the body.

Personally its no booze for me 24 hours before flying.