Why hypoxia training?
The airplane cabin is pressurized to create an environment which is physiologically suitable for humans. A loss of cabin pressure can be caused by for example structural failures in the cabin, malfunction of the pressurization system or by incorrect activation of pressurization control.
Loss of the cabin pressure can very soon lead to incapacitation of the crew due to hypoxia, with inability to perform the right maneuvers in time. Once you or your passengers experience early hypoxia symptoms you must increase the oxygen amount. There are two options: descent to lower altitude or use supplemental oxygen.
Suspicion of hypoxia? No question! Action!!!
Hypoxia is a well-known risk in both military and civil aviation and is for example considered the number one flight safety issue in US Navy today. Due to this fact, yearly normobaric hypoxic training is mandatory for US Navy pilots. In military aviation hypoxia awareness training has been a part of the flight safety education since long. Until recently hypobaric chamber training has been the golden standard.
As recent research has shown severe medical complications due to longstanding hypobaric exposure, there is a growing interest in normobaric training, with the hypoxia demonstration performed on ground level without altitude chamber. For most commercial aircrew this has not been an option – until today. Is hypoxia then just a military problem? No, unfortunately every year there are hypoxia incidents and accidents also in civil aviation, the most tragic and well-known was the Helios Airways 522 flight from Larnaca to Athens in 2005. The Boeing 737 flight ended up in the mountains near Athens due to crew hypoxia.
The report from the Greek Air Accident Investigation and Aviation Safety Board included a recommendation that EASA/JAA should require practical hypoxia training as a mandatory part of flight crew and cabin crew training. Ever since there has been discussions in the aviation authorities around the globe about implementing hypoxia training.