On August 14, 2005, 121 people died in the crash of Helios Airways Flight 522 after the aircrew became hypoxic due to the air pressurization system being incorrectly set to manual.
On April 1, 2011 a glider flight from Boulder, CO ended in a fatal accident after the pilot had spent 14 minutes above 22,000 feet. From there the sailplane spiraled to the ground. The accident report found hypoxia of the pilot to be the most likely cause.
These accidents were on my mind when I attended yesterday’s Hypoxia Simulation Training session, provided by AirCare Facts at Independence Aviation in Centennial, CO.
After an hour of classroom training covering the causes as well as the potential signs and symptoms of Hypoxia, I had the opportunity to participate in a simulation of low pressure conditions at up to 28,000 feet. This was accomplished by breathing through a mask feeding reduced levels of oxygen into the respiratory system.
Hypoxia is an insidious killer because it is often very difficult to recognize any symptoms before it is too late. The potential symptoms even include feelings of wellbeing and euphoria, which may make it even less likely that a pilot would take corrective action before passing out (and eventually dying – either due to oxygen deprivation or due to the plane crashing in uncontrolled flight).
The only good news is that the symptoms of hypoxia tend to be specific to each individual and relatively constant over time. Hence, it is possible for everyone to experience and “get to know” their early indications that something may be amiss. Recognizing these indications early is likely one’s best (and maybe only) chance to take the necessary actions.
At the earliest onset of hypoxia symptoms at altitude it is vitally important to act immediately (while still being “usefully conscious”). Normally this means beginning a rapid descent to lower altitudes where the air pressure is higher and normal oxygen saturation levels are restored relatively quickly (normally within a few minutes).
I took the following video during my own training session so that I would be able to see my own reaction and be able to remember my specific symptoms.
I can recommend to any pilot to participate in such a simulation. Knowing your individual symptoms may one day safe your life.