- What is hypoxia? - Hypoxia is a condition where the human body is deprived of sufficient oxygen needed for normal bodily function.
- How can I get hypoxia? - Hypoxia is not a disease, but rather a temporary condition that can happen if your aircraft has a loss of cabin pressure.
- How do I avoid hypoxia while flying? - Modern airliners have a variety of systems that maintain cabin pressure at a safe level that will maintain cabin pressure and prevent you from experiencing hypoxia.
- What happens if cabin pressure is lost? - Should there be a loss of cabin pressure, emergency oxygen systems may be deployed automatically or by the flight crew, and the pilots will either restore cabin pressure or descend to a low enough altitude where the emergency oxygen system is needed.
- Why is hypoxia bad? - Hypoxia affects the central nervous system, and those effects may range from impaired judgment and decision making capability, to unconsciousness and death.
- Has hypoxia caused plane crashes?Hypoxia has been a factor in numerous crashes over the years, including a 2005 crash of a Helios Airways 737 in 2005. Perhaps the most famous hypoxia crash is the 1999 crash of a private jet that killed professional golfer Payne Stewart.
A brief overview of hypoxia
Hypoxia is a condition where the human body is deprived of sufficient oxygen needed for normal bodily function. Hypoxia affects the central nervous system, and those effects may range from impaired judgment and decision making capability, to unconsciousness and death.
Hypoxia is one of the risks faced by anyone who flies because it can occur at high altitudes. In fact, the FAA requires that aircraft that fly above 12,500 feet above sea level have equipment on board that can prevent aircraft occupants from experiencing hypoxia.
While commercial airliners routinely fly at altitudes well above 20,000 feet, and some may even fly above 40,000 feet, most airliners are pressurized at a much lower altitude, about 7,500 feet above sea level, which is about the same altitude as the city of Addis Ababa, Ethiopia, and about 50% higher than the altitude of Denver, Colorado.
Symptoms of mild hypoxia include impaired judgement and decision making ability. The longer someone is exposed to the low oxygen conditions that induce hypoxia, the more severe the effects may be, including unconsciousness and even death.
In a typical airliner, hypoxia can occur when the aircraft is flying at a relatively high altitude,and where there is also either a slow or a catastrophic loss of cabin pressure.
When an airliner experiences a sudden loss of cabin pressure, flight crews are trained to do three key things that will allow the crew to continue to fly the aircraft safely:
- Put on oxygen masks that provides supplemental oxygen,
- Ensure that the the emergency oxygen system is activated for passengers, and
- Descend to a low enough altitude, typically at or below 10,000 feet above sea level, that will allow the crew and passengers to breath normally without using any supplementary oxygen system.
The FAA also provides extensive and detailed guidance for pilots on the risks of hypoxia and how to avoid it while flying.
Additional medical information
http://airsafe.com/issues/medical/hypoxia.htm -- Revised 16 June 2015