14 Sep 97 15:09, Don Burke wrote to Jay Hanig:
 JH>> Whereas 1.5 psi of O2 may not be adequate for clear thinking, 7.5 psi
 DB> is more than enough.  You need to use O2, not compressed air in a
 DB> decompression incident.
 DB> One of the hot items in SCUBA diving is enriched oxygen mixtures,
 DB> generally called NITROX.  Do you suppose carrying a 50/50 O2/N2
 DB> mix would be signifigantly safer than 100% O2?
I'm operating under the limitation of not knowing what the total atmospheric 
pressure is at altitude.  I know that sea level is roughly 15 psi, and that 
the pressure drops to half that value at 18,000 feet.  The 50/50 nitrox 
mixture you suggested would have a partial pressure of oxygen of 3.75% at 
18,000 feet.... more than enough.  The problem is what happens at normal 
cruising altitudes for the average airliner:  I know it'll be less, but I 
don't know how much less.
Maybe some of our airline buddies might favor us with with some figures of 
altitude vs atmospheric pressure?
Jay
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