How Hypoxic do You Fly?

At the 2002 15-meter Nationals in Tonopah, Nevada, Dr. Philippe was using his new pulse oximeter to test pilots' oxygen saturation while on the grid before takeoff. I remember his comments that many were so low he would not have let them out of his office.

(a) General. No person may operate a civil aircraft of U.S. registry—

(1) At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;

(2) At cabin pressure altitudes above 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and

(3) At cabin pressure altitudes above 15,000 feet (MSL) unless each occupant of the aircraft is provided with supplemental oxygen.

We were all tested on our knowledge of FAR 91.211, which effectively states that from 12,500ft to 14,000ft, we have 30 minutes without required oxygen, and above 14,000ft, we must use supplemental oxygen. However, is that regulation best for your personal minimums?

Many organizations recommend or require supplemental oxygen above 10,000ft. I believe oxygen is cheaper than brain power; therefore, I set my Mountain High EDS to start at 10,000ft and leave it all day with no adjustments.

The FAA Glider Flying Handbook doesn't mention hypoxia very well, but it does bring up a good point to consider:  "At 18,000 feet, air density is only one-half that at sea level. The purpose of breathing is to supply oxygen to the blood and remove carbon dioxide. In each breath at 18,000 feet, the pilot breathes in only half as much oxygen as at sea level. This is not enough to deliver an adequate supply of oxygen to the blood, and the situation worsens as altitude increases."

One of my favorite symptoms of hypoxia is 'Euphoria,' which describes half of my flight... My pre-takeoff oxygen checklist to help avoid hypoxia symptoms:

Here is a quick story of why I always remember the above checklist.

A pilot who will remain nameless was cruising in the wave when realizing he hadn't turned on the oxygen. This pilot, who we will only mention, was flying a Nimbus 2 at the time. He undid his belt, turned around in the seat, reached back, and turned on the oxygen, which many of you know is difficult on the ground, let alone at some unmentionable altitude. Perhaps not a choice he would have made if not already hypoxic. Luckily, he did not get stuck facing the wrong direction and returned to admit this tale.

 Garret Willat holds a flight instructor rating with over 8000 hours in sailplanes. His parents have owned Sky Sailing Inc. since 1979. He started instructing the day after his 18th birthday. Since then, Garret has represented the US Junior team in 2003 and 2005. He graduated from Embry-Riddle with a bachelor's degree in Professional Aeronautics. Garret represented the US Open Class team in 2008 and 2010 and the Club Class team in 2014. Garret has won 3 US National Championships.