Hypoxia is a condition brought on due to inadequate oxygen and it can have dire consequences.  Pilots who fly at high altitudes are at risk of becoming hypoxic, and it is critical that they are properly trained on how to recognize the earliest symptoms both in themselves and in others.  In 2005, Helios flight 522, bound for Athens, Greece, crashed killing all 121 people on board.  Investigators determined that the cabin never pressurised during the ascent to 35,000 feet, the crew was incapacitated by hypoxia preventing them from flying to lower altitudes and attempting a landing.

When the body is deprived or starved for oxygen due to altitude, the impairment can prevent the pilot from recognizing the hypoxia and from reacting properly.  The below video shows the serious effect of hypoxia on a pilot undergoing training in an altitude chamber.

The initial symptoms include a general dulling of the senses, clumsiness or drowsiness.  Some compare the feeling to being slightly intoxicated.

Without suplemental oxygen or flying to lower altitudes, the symptoms then worsen.  Pilots may suffer from any combination of the following symptoms:

  • dizzyiness
  • tingling in the skin
  • headache
  • racing heart
  • changes in vision
  • bluish tint to the lips

Due to the effect on the brain, however, the pilot may be completely unaware that they are having any problems.

Next week, I’ll review the way that pilots are trained to recognize and respond to hypoxia using either an altitude chamber or a reduced oxygen breathing device (ROBD) system.