Greatest Helicopter Altitude
Country: United States
Date: April 2006
How can helicopter fly up to Mount Everest where
the air is so thin?
The ability of a helicopter to fly is based in the density of the
air. The more dense the air the better it performs. As it seems
you know, at the higher parts of the atmosphere it is more
difficult. Ultimately, when the air has too little density, the
helicopter can not fly.
The density of air is mostly a function of two variables - pressure
and temperature. At the top of a high mountain the pressure is
greatly decreased (1/2 the sea level pressure at 18,000 feet), but
this is made up somewhat (but not completely) by the colder
temperatures (decreasing about 3.5 F for each 100 feet).
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Update: June 2012