A new NPRM would change the requirements for when pilots must wear oxygen masks in pressurized aircraft under Parts 91 and 135. The proposed flight-level limits are not yet in force.
Published: September 25, 2026 · Regulatory status: Notice of Proposed Rulemaking · Comment deadline: November 23, 2026. Proposal only — current requirements remain in force
Quick Answers
What is the FAA oxygen mask proposal?
The FAA proposes raising the oxygen-mask thresholds for some Part 135 operations and changing the Part 91 mask-wearing requirement. The central proposed thresholds are FL410 for two-pilot Part 135 operations and FL350 when only one pilot is at the controls. For Part 91, quick-donning masks available to each pilot could eliminate the requirement that a pilot wear one continuously.
Are the FL350 and FL410 thresholds effective now?
No. They are proposed amendments in an NPRM published September 24, 2026. Operators must continue following the existing regulations unless the FAA adopts a final rule with an effective date.
When are comments due?
The FAA must receive comments by November 23, 2026. The proposal is listed as FAA-2026-12145, Notice No. 26-17.
Quick Compliance Summary
| Item | What the NPRM says |
|---|---|
| Regulator | Federal Aviation Administration (FAA) |
| Instrument | Notice of Proposed Rulemaking: “Flight Operations: Pilot requirements; Use of oxygen” |
| Publication date | September 24, 2026 |
| Regulations addressed | 14 CFR Parts 91 and 135 |
| Part 135, two pilots | PROPOSED Above FL410, at least one pilot at the controls would wear a secured and sealed mask. |
| Part 135, one pilot at controls | PROPOSED Above FL350, the pilot at the controls would put on and use an approved mask. |
| Part 91, pressurized aircraft | PROPOSED Above FL350, a pilot would wear a mask unless each pilot has an available quick-donning mask. |
| Comment deadline | November 23, 2026 |
| Legal status | The NPRM is not a final rule. Existing requirements remain applicable. |
Do not update manuals or SOPs based on the proposed thresholds alone. The NPRM invites comments; it does not authorize operations under the proposed limits. Check the current text of 14 CFR 91.211 and 135.89, applicable aircraft documentation, and any later FAA action.
Who Should Read This
- Part 135 commuter and on-demand operators, including charter and air-taxi providers
- Part 91 general aviation and business-aviation operators of pressurized aircraft
- Chief pilots, flight-operations managers, and safety-management teams
- Training departments updating high-altitude and depressurization scenarios
- Maintenance and avionics teams responsible for oxygen-system readiness and mask availability
- Aircraft manufacturers, pilot associations, and operators preparing comments for the FAA docket
At a Glance: Current Rule Versus Proposal
| Operation | Current requirement (simplified) | FAA proposal |
|---|---|---|
| Part 135 — two pilots at controls | CURRENT At least one pilot wears a mask above FL350. | PROPOSED At least one pilot wears a mask above FL410. |
| Part 135 — one pilot at controls | CURRENT Existing rules include mask use above FL250 when a pilot leaves the duty station; the two-pilot threshold also applies in its stated circumstances. | PROPOSED The pilot at the controls wears a mask above FL350. |
| Part 91 — pressurized aircraft | CURRENT A pilot must wear a secured and sealed mask above FL410; above FL350, a mask is required if only one pilot is at the controls. The remaining pilot must also use a mask when the other leaves the controls above FL350. | PROPOSED With quick-donning masks available to each pilot, a pilot would not need to wear one continuously at any altitude for which the aircraft is certified. Without them, a pilot would wear one above FL350. |
The table summarizes the NPRM’s discussion and proposed regulatory text. It is not a substitute for the complete regulations, which include additional conditions and oxygen availability requirements.
What the FAA Wants to Change
The NPRM responds to Section 834 of the FAA Reauthorization Act of 2024. That provision directed the FAA to consider changes to the Part 135 oxygen-mask requirements. The agency also proposes amending Part 91, citing modern aircraft design, accumulated operational data, and differences between U.S. rules and ICAO standards.
For Part 135, the proposal draws a clear distinction between two-pilot operations and situations where only one pilot is at the controls. In a two-pilot operation, the proposed FL410 threshold would raise the altitude at which at least one pilot must wear a mask. When only one pilot is at the controls, the proposed threshold would be FL350.
For Part 91, the proposal would make the availability of quick-donning masks central. The proposed text would allow pilots to operate without continuously wearing a mask when each pilot has a qualifying quick-donning mask available. The FAA describes such a mask as one that can be placed, secured, sealed, and supplying oxygen with one hand within five seconds.
The NPRM also contains oxygen-supply requirements beyond the mask-wearing thresholds. In particular, its proposed Part 91 text retains an emergency oxygen-supply requirement for pressurized aircraft operating above FL250. Operators should review the complete proposed text before assessing how the proposal could affect their operations.
Why the FAA Says It Is Acting
The FAA says current U.S. requirements are more stringent than the relevant ICAO mask-availability standards. The proposal aims to reduce the operational burden while maintaining what the agency considers an appropriate level of safety. The FAA also says aircraft design and operational data have improved since earlier attempts to revisit the rules.
In its analysis, the FAA reviewed more than 20 million flight hours above FL250 across Part 91 and Part 135 operations between January 2015 and May 2025. It identified about 200 reported decompression events during that period. The agency classified four as possible rapid or explosive events; two rapid decompressions resulted in accidents, while the other events ended with safe landings.
That is the FAA’s risk assessment, not a guarantee that high-altitude depressurization is harmless. The NPRM discusses hypoxia, short time-to-act windows, and the importance of recognizing and responding to a loss of pressure. Operators should read the analysis and consider whether their aircraft, crews, and procedures align with the assumptions underlying the proposal.
Operational and Maintenance Impact
If adopted as proposed, the changes could reduce the time spent wearing masks and lower the frequency of oxygen servicing for some aircraft. The FAA notes that a tank refill can cost between $100 and $400. Its estimate says that each one-percentage-point reduction in servicing among roughly 4.7 million relevant Part 91 and Part 135 operations could correspond to $4.7 million to $18.6 million in annual savings.
That figure is a sensitivity estimate, not a guaranteed saving or a forecast that every operator will experience the same reduction. Actual effects would depend on operating profile, aircraft equipment, oxygen-system configuration, and whether the proposal is finalized as written.
Maintenance teams should not treat this as a reason to defer oxygen-system inspections or servicing. The proposal concerns when pilots must wear masks; it does not remove the broader need for serviceable oxygen equipment, emergency procedures, or compliance with current requirements.
What Operators Should Do Now
- Keep current compliance in place. Do not apply the proposed FL350 or FL410 thresholds until a final rule becomes effective.
- Map the affected fleet. Identify Part 91 and Part 135 aircraft with pressurized cabins, crew configurations, quick-donning mask capability, and relevant approved operating limitations.
- Review procedures and training. Check oxygen-mask donning, crew coordination, emergency descent, and depressurization training against the aircraft manuals and current rules.
- Assess safety assumptions. Compare the NPRM’s risk analysis with your own fleet data, maintenance history, crew workload, and operating environment.
- Model costs carefully. Treat the FAA’s servicing estimates as scenario inputs, not guaranteed savings or approved budget reductions.
- Submit evidence-based comments. Operators and technical stakeholders can comment on safety, feasibility, fleet differences, training, and implementation by November 23, 2026.
Key Dates
| Milestone | Date |
|---|---|
| FAA NPRM published in the Federal Register | September 24, 2026 |
| Comments due to the FAA | November 23, 2026 |
| Possible effective date | Not specified; depends on final agency action |
ARW Take
This proposal could matter most to pressurized business-aircraft and on-demand operators, but the headline thresholds are only part of the story. The key operational distinction is between two-pilot Part 135 operations, single-pilot-at-controls situations, and Part 91 aircraft equipped with quick-donning masks.
For now, the compliance message is simple: FL350 and FL410 are proposed limits, not new operating permissions. Keep current procedures in place, review the actual NPRM, and use the comment period to raise fleet-specific safety and implementation issues.
Source Documents
- FAA, Flight Operations: Pilot requirements; Use of oxygen — NPRM, Docket FAA-2026-12145, Notice No. 26-17.
- U.S. Government Publishing Office, Federal Register text, September 24, 2026.
- FAA, Recently Published Rulemaking Documents.
- Current regulations: 14 CFR 91.211 and 14 CFR 135.89.
FAA oxygen mask proposal: FAQs
Does this NPRM change what pilots must do today?
No. Until the FAA issues a final rule and its effective date arrives, operators must follow the current regulations and approved aircraft documentation.
What does “above FL410” mean in the proposal?
For the proposed two-pilot Part 135 provision, the requirement would apply when operating above FL410. The exact legal wording and applicability are in the proposed amendment to 14 CFR 135.89.
Would Part 91 pilots still need oxygen available?
The NPRM addresses mask-wearing and includes separate oxygen-availability requirements. It does not mean oxygen equipment or emergency supplies can be removed. Review the proposed text and current 14 CFR 91.211.
Can an operator start using the proposed thresholds after submitting comments?
No. Filing a comment does not change the rules. The proposal becomes actionable only if the FAA adopts a final rule and that rule takes effect.
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AviationRegWatch provides regulatory information for industry professionals. This article is an informational summary, not legal, medical, or airworthiness advice. Consult the official rule text, your regulator, aircraft manufacturer, and qualified compliance advisers before making operational decisions.