FAA proposes relaxed oxygen-mask rules for pressurised aircraft

The FAA is proposing changes to oxygen-mask requirements for pilots operating pressurised aircraft under Parts 91 and 135, according to AVweb. The proposal, published Thursday, would allow pilots to fly at higher altitudes without requiring continuous mask wear.

Under current Part 91 regulations, one pilot must generally wear and use an oxygen mask above FL350, although two-pilot crews equipped with quick-donning masks are exempt through FL410. Under the proposal, pressurised aircraft equipped with quick-donning masks could operate at any altitude for which the aircraft is certificated without requiring a pilot to continuously wear a mask. The FAA said in its notice that "the proposed amendments would allow the operation of airplanes at higher altitudes without requiring at least one pilot at the controls to wear and use an oxygen mask."

The FAA also said that "if adopted, these proposed changes would reduce regulatory and economic burdens on operators by changing certain requirements pertaining to pilots' use of oxygen masks."

Part 135 threshold changes

For Part 135 operations using more than one pilot, the proposal would raise the altitude at which at least one pilot must wear an oxygen mask from FL350 to FL410. The single-pilot operation threshold would also increase, from FL250 up to FL350. These updates come in response to a requirement in the FAA Reauthorization Act of 2024.

Estimated savings

The FAA estimates oxygen servicing costs between $100 and $400 per fill. Based on roughly 4.7 million annual Part 91 and 135 turbojet and multiengine turboprop operations, the agency estimates operators could save between $4.7 million and $18.6 million annually for every 1% of those operations that avoid an oxygen servicing event under the revised rules.

For Part 91 operators, the change removes the requirement to continuously wear an oxygen mask when equipped with quick-donning masks, which could reduce oxygen servicing events and associated costs. Part 135 operators face higher thresholds but are not affected by the continuous-wear requirement change. The reporting does not specify which operator category—or how many operations—would likely avoid servicing events under the revised rules.

Comments on the proposal are due 23 November.