If the cockpit lost pressure while the aircraft was above the<unk> , even a positive pressure oxygen mask could not sustain pilot consciousness. The<unk>  or<unk> 's line is a measure of altitude above which atmospheric pressure is sufficiently low that water boils at the normal temperature of the human body. Exposure to pressure below this<unk>  results in a rapid loss of consciousness, followed by a series of changes to cardiovascular and neurological functions, and eventually death, unless pressure is restored within 60–90 seconds. On Earth, the<unk>  is around above sea level, above which atmospheric air pressure drops below 0.0618 atm (6.3 kPa, 47 mmHg, or about 1 psi). The U.S. Standard Atmospheric model sets the<unk>  pressure at an altitude of . The term is named after United States Air Force General Harry George<unk> , who was the first to recognize this phenomenon.
Armstrong limit
Place of articulation
Posselt's envelope of motion
Range of Motion
Trip 
Arm recoil
Range of motion
Jim 