CFI Brief: Hypoxia

Monday’s ground school post had some great information on hypoxia; if you have not yet read it I would suggest doing so. Throughout your aviation training you will continually learn about aeromedical factors that affect pilots such as hypoxia which in my opinion is one of the most dangerous things a pilot can encounter. Just look at some of the common symptoms: euphoria, visual disturbances, dizziness, confused thinking, apprehension, sense of well-being…I mean, can you imagine as a pilot experiencing even just one of these symptoms? The big problem with hypoxia is that it sneaks up on you and as a pilot you may not realize you have become hypoxic.

In July 2008 the flight crew of Kalitta 66 on a cargo run to Ypsilanti, Michigan suffered hypoxia. If not for the quick thinking and assistance from ATC this flight could have had a tragic ending.  The ATC audio recording can be found below. Rather than continuing to talk about hypoxia, take a listen to the audio, that should put it in perspective for you.

http://media.natca.org/conferences/archieawards/2009/audio/greatlakes-region2.mp3 (link no longer active)

You can hear in the audio track the pilot’s slow speech and difficulty with communication. At one point he states that he is unable to control the altitude and airspeed of the aircraft and then seconds later proceeds to say “everything is A-OK!”—a prime example of the euphoria a hypoxic victim might experience.

A few years back, I was on a return flight home from Burbank airport in LA after spending the day at Six Flags with a few friends. We departed the airport VFR just after 10 PM en-route to San Diego. The planned route would take us about 4 miles off the coast at 7,500 MSL, and the weather was great, as usual for SoCal. About 30 minutes in, I noticed my two buddies in the aft seats laughing up a storm. I inquired as to what was so funny. They didn’t know, it just seemed like they were having the time of their lives. A few more minutes went by and they were still back there laughing when it finally dawned on me, I bet these two are getting hypoxic. Remember, hypoxia can occur as low as 5,000 feet when flying at night (symptoms will most likely first affect night vision). We had all just spent the day walking around six flags in the heat and we were all pretty worn out, this was also my buddies’ first time flying in a non-pressurized aircraft (all contributing factors). I initially thought to myself “this is pretty funny,” but began to realize the implications if I was to join them in their hypoxic state.

We ended up descending down to 5,500 and landed back home 20 minutes later. Once on the ground I explained to them what I thought may have happened causing them to have the backseat giggles. For me, this was a great learning experience and gave me a story to share with future and current pilots.

Do you have a story relating to hypoxia? Share in the comments section below, we would love to hear it.

1. Which statement best defines hypoxia?
A—A state of oxygen deficiency in the body.
B—An abnormal increase in the volume of air breathed.
C—A condition of gas bubble formation around the joints or muscles.

2. Susceptibility to carbon monoxide poisoning increases as
A—altitude increases.
B—altitude decreases.
C—air pressure increases.

Answers will be posted Monday in the comments section, good luck!

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