Oxygen basics for pilots

Did you know that not all oxygen is the same?

Supplemental oxygen is used to prevent hypoxia during flying.

Supplemental oxygen is used to prevent hypoxia during flying. Reduced atmospheric pressure means less oxygen in your lungs and less oxygen in your tissue. Symptoms of hypoxia are cyanosis (a blue tint to the tissue around the tips of your extremities and lips), tingling or numbness in the extremities, and a feeling of euphoria. As hypoxia progresses you become sleepy

If not corrected it will lead to unconsciousness and death.

FAR 91.211 (supplemental oxygen) provides oxygen use requirements including the altitudes at which pilots must use supplemental oxygen and provide oxygen for passengers. Oxygen is also recommended when flying at night at above 5000 feet (see this post on the oxygen use requirements at Sportys.com/blog.)

Pilots can monitor their oxygen saturation, or SPO2, which is the percentage of oxygen their blood cells are carrying, via a pulse oximeter. Normal oxygen saturation is 96% or higher when breathing the air on the ground. This saturation number will decrease as altitude increases due to the atmosphere becoming less dense the higher we fly.

Our atmosphere is made up of 21% oxygen and 78% nitrogen; the remaining 1% is small amounts of different gases.

The most common way to deliver oxygen is from an installed system or a portable system. Both systems consist of a tank, a regulator (controls the flow), and either a mask or nasal cannula that the pilot and passengers wear. Oxygen cannulas are not approved for use above 18,000 feet. Above this altitude, you must wear a mask. Some systems also include a directional flow indicator to indicate that oxygen is moving from the tank to the mask or cannula.

The most common way to deliver oxygen is from an installed system or a portable system.

All oxygen is not the same.

There are three grades of oxygen: medical oxygen, aviator oxygen, and industrial oxygen.

Medical and aviator oxygen is 99.5% pure, and industrial, or welders oxygen, is 99.2% pure. The biggest difference between medical and aviator oxygen is the moisture content. Medical oxygen can contain 67 ppm of moisture. Industrial oxygen can contain 50 ppm of moisture. Aviation oxygen can contain 7 ppm of moisture—this is very dry oxygen as moisture in an oxygen system can freeze at altitude and prevent the system from working correctly. Another difference is that medical oxygen typically requires a prescription from a physician.

The last grade is industrial oxygen which is used for welding purposes. This grade of oxygen typically has a high percentage of moisture and is not filtered for very small particulates and is not as pure.

You should always ensure that you are using aviator oxygen when flying. Use of other grades can lead to hypoxia.

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Eric Carnahan

Eric has always been interested in flying, and his father paid to have him and his brother go up in a Cessna when they were kids. After retiring from the Navy, he decided that it was time to learn to fly real aircraft. His only regret is that he did not learn sooner. The real pleasure of flying for Eric is flying kids for EAA’s Young Eagles program. Nothing gives him more satisfaction than taking a young person up for their first GA flight, usually in his Piper 235. Now he feels lucky to work on Sporty’s customer service team and teach at Sporty’s Academy.

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