From kls Sun Mar  9 22:55:40 1997
Newsgroups: sci.aeronautics.airliners
Path: bounce-back
Date: 09 Mar 97 22:55:40 
From: Andrew Goldfinger <Andy.Goldfinger@jhuapl.edu>
Subject: 42,000 feet
Message-ID: <airliners.1997.686@ohare.Chicago.COM>
Approved: kls@ohare.Chicago.COM
Sender: kls@ohare.Chicago.COM
Organization: apl

     I recently flew at 41,000 feet in a commercial airliner (actually FL
410, I assume).  According to a friend, at around 42,000 feet free
flowing oxygen is no longer adequate for maintenance of life, and
pressure breathing is required.  Therefore, the emergency oxygen system
(as an SWA flight attendent put it: "these are not party hats") on
commercial aircraft would not be sufficient.  Does this limit the
practical ceiling of commercial flights?  What is done for emergency
oxygen on the Concord?