The FAA has proposed raising the altitudes at which a pilot must wear an oxygen mask, in a rulemaking directed by section 834 of the FAA Reauthorization Act of 2024. Current rules require oxygen masks to be worn from as low as 25,000 feet in some circumstances, thresholds largely unchanged since the 1960s and stricter than the international standards set by the International Civil Aviation Organization. The FAA says the case for change rests on a decade of new safety data: reviewing more than 20 million flight hours logged above 25,000 feet by general aviation and commuter and on-demand operators between 2015 and 2025, the agency found roughly 200 reported pressurization events, the great majority of which ended with the aircraft landing safely and without incident.

WHAT WOULD CHANGE

For commuter and on-demand operations under 14 CFR Part 135, the altitude at which at least one of two pilots at the controls must wear an oxygen mask would rise from 35,000 feet to 41,000 feet, and the altitude at which a single pilot alone at the controls must do so would rise from 25,000 feet to 35,000 feet. For general aviation under Part 91, the FAA is proposing a more substantial change: removing the current altitude ceiling altogether, so that a pilot would not need to wear a mask at any altitude for which the aircraft is certified, provided a quick-donning mask, one that can be put on with one hand within five seconds, is available. Where no quick-donning mask is fitted, a pilot would still need to wear a mask above 35,000 feet. The changes would not apply to Part 121 scheduled airline operations, which were already adjusted by Congress in a separate 2020 rule.

WHY THE FAA BELIEVES IT IS SAFE TO DO THIS

Of the roughly 200 pressurization events the FAA reviewed, only four were classed as rapid or explosive rather than gradual, and only one resulted in a fatal accident, a 2023 Cessna 560 crash that investigators attributed to the aircraft being flown in an unairworthy condition and to the pilot losing consciousness before reaching an altitude where oxygen use was even required, rather than to the altitude thresholds themselves. The agency also points to design changes since the 1980s, when a similar proposal was withdrawn for lack of data, including modern pressurised aircraft built to limit cabin altitude after a failure and improved checklist procedures introduced after a fatal 1999 Learjet 35 depressurisation accident that killed golfer Payne Stewart and five others. The FAA estimates the changes would save operators between 4.7 million and 18.6 million dollars a year in reduced oxygen-servicing costs, based on typical refill charges of 100 to 400 dollars, for every one percentage point of the roughly 4.7 million affected annual flights that no longer need servicing.

Note: This article summarises a Federal Register notice running to more than sixty printed pages, covering decades of regulatory history, detailed physiological research on hypoxia and time of useful consciousness, individual accident case studies, and a full regulatory impact analysis, none of which is reproduced here in full. Readers who need the complete technical detail, including the underlying safety data and the precise proposed rule text, should consult the original notice at the source link below. Comments on the proposal are due by 23 November 2026 (Docket No. FAA-2026-12145), submitted via regulations.gov.