OXYGEN REGULATIONS FOR PRIVATE PILOTS AND UNPRESSURIZED AIRCRAFT
There is a lot of confusion regarding the regulations surrounding oxygen use and oxygen systems in aircraft. Within Title 14 of the Code of Federal Regulations (CFRs), there are regulations regarding airmen use of oxygen for both Part 91 operations and Part 135 operations and then additional regulations regarding installation of oxygen systems for type certificated aircraft under Part 23. So, the lack of clarity is understandable.
The regs can be summarized as follows: (1) for non-commercial private pilots in unpressurized aircraft, you must use oxygen above 12.5k MSL for more than 30 minutes and always above 14k MSL; and (2) for experimental aircraft there are NO limitations on oxygen system installation; and (3) for type certificated aircraft approved for flight above 14k MSL, an oxygen system with minimum requirements must be installed as part of the certification of the aircraft. If interested, you can find more background at 14 CFR 91.211 and 14 CFR 23.1441.
PILOT USE REQUIREMENTS – RULES ARE VAGUE AND MINIMAL
For non-commercial operations in unpressurized aircraft, the private pilot must use oxygen above 12.5k MSL for more than 30 minutes and above 14k MSL. All passengers must use oxygen above 15k MSL. Contrary to popular opinion, there is NO actual requirement for a specific amount of oxygen, NO requirement for a mask, and NO requirement for the source of the oxygen. The specific oxygen concentration requirement and the mask requirement are actually only part of certificated aircraft systems requirements and have nothing to do with the pilot use requirement. Surprisingly, there is also no requirement for any high altitude training or endorsements for piloting an unpressurized aircraft at any altitude.
OXYGEN SYSTEM REQUIREMENTS
For experimental aircraft, oxygen systems can be portable, built-in, or semi-built-in. There are no limitations for oxygen systems in experimental aircraft. For type certificated aircraft in private non-commercial operation, any portable system may be used to satisfy the rules. However, for type certificated aircraft that are approved for operation above 14k MSL, these aircraft must have an oxygen system installed as part of the certification process. While that oxygen system cannot be uninstalled or removed, for private non-commercial operations in unpressurized aircraft there is actually no requirement to use that oxygen system. In private settings, a pilot can use a portable system to satisfy the oxygen use rules even with an installed system present in the aircraft. With advances in oxygen delivery technology, this is analogous to using an iPAD for situational awareness to supplement an old VOR navigational aid required for IFR flight.
