NBAA's Longtime Advocacy on Pilot Oxygen Requirements Leads to Proposed Rule Change

The FAA has proposed a change to rules requiring pilots to wear oxygen masks in response to NBAA-led provisions in the FAA Reauthorization Act of 2024. The proposed rule, Flight Operations: Pilot Requirements; Use of Oxygen, would relax the altitude requirements for pilots to wear oxygen masks, particularly for Part 91 general aviation operations involving pressurized aircraft.

For Part 91 aircraft operations, if each pilot has a qualifying quick-donning oxygen mask, the pilot would no longer be required to wear the mask at FL350 or FL410 simply because of altitude.

Section 834 of the FAA Reauthorization Act of 2024 directed the FAA to issue a formal NPRM raising the altitude thresholds in the Part 135 oxygen mask rules. NBAA and other organizations built the safety-data case that altitude-based mask thresholds set in the 1950s and 1960s don't reflect modern aircraft design.

This proposed rulemaking is in part a response to a 2021 petition from Merck to be exempted from 14 CFR § 91.211(b)(1)(ii) — the rule requiring a pilot to wear an oxygen mask above FL410. NBAA submitted comments supporting Merck's petition request, arguing that wearing an oxygen mask decreases overall safety, essentially making the case that modern aircraft design mitigations made the mask requirement obsolete for two-pilot crews with quick-donning masks available.

"NBAA has long been an advocate for ensuring regulations evolve with technology advancements," said NBAA's Senior Vice President of Operations. "The association is pleased to see its years-long advocacy bear fruit in the recent proposed rule."

The FAA's proposal:

• Raises the two-pilot mask threshold under Part 135 from FL350 to FL410
• Raises the single-pilot mask threshold from FL250 to FL350
• Revises Part 91 to let pilots fly at any certified altitude without a mask, if quick-donning masks are available

The proposal would also amend Part 135 requirements found in § 135.89. In short: for Part 91 operations in pressurized aircraft, no pilot must wear or use oxygen solely because of altitude if qualifying quick-donning masks are available; without qualifying masks, one pilot must still wear/use oxygen above FL350. For Part 135, the two-pilot threshold rises from FL350 to FL410 and the single-pilot threshold from FL250 to FL350.

The proposed rule relies on the existing FAA definition of quick-donning mask: the mask must be capable of being taken from its ready position with one hand, within five seconds, without disturbing eyeglasses or delaying emergency duties, and must allow for normal communications.

The FAA said this rulemaking is justified due to improvements in pressurization and warning systems in modern aircraft, the rare rate of pressurization failures at high altitude, and current FAA rules being more restrictive than International Civil Aviation Organization standards.

The FAA estimates that even a 1-percentage-point reduction in applicable servicing requirements could represent approximately $4.7 million–$18.6 million annually across the affected Part 91 and Part 135 fleet, considering reduced oxygen consumption, servicing frequency, maintenance burden and associated operating costs.

Comments are due Nov. 23. NBAA will coordinate comments on behalf of its member organizations.