Pilot George Braly recalls a flight in which his portable oxygen line becomes kinked and he ultimately loses conciousness. George is awakened by ATC and is able to increase the oxygen flow and safely descend from the high-altitude flight. In this episode AIN delves into the issue of hypoxia by examining both portable and built-in oxygen systems. Additionally we discuss the FAA regulations that require one pilot when flying in a pressurized aircraft above 41,000 to use an oxygen mask at all times. Studies have shown that 82 percent of business aircraft pilots openly disregard this rule, and this episode discusses the human factors involved in oxygen mask use on long flights and possible solutions to this problem.