The FAA has amended its regulations to facilitate certification of Part 25 air transport aircraft, cabin-pressurization systems, and oxygen-dispensing equipment for operation at high-elevation airports—namely those above 8,000 feet msl.

Current regulations require that the cabin pressure altitude on transport airplanes remain at or below 8,000 feet in normal operating conditions. The new amendments, effective on July 17, eliminate a burden on industry by removing a rule that calls for applicants to meet specialized design-modification requirements under an equivalent level of safety finding and file a petition for exemption when seeking to operate above 8,000 feet.

Under the new rules, when aircraft are operating at airports at or above 8,000 feet, cabin altitude may be up to or greater than the airport elevation by 2,000 feet, provided that in the event of a “probable failure” of the pressurization system, “the cabin altitude must not exceed 15,000 feet, or 2,000 feet above the airport elevation, whichever is higher.” Also, “the cabin pressure high altitude warning alert may be provided at up to 15,000 feet, or 2,000 feet above the airplane’s maximum takeoff and landing altitude, whichever is greater.”

Regarding passenger oxygen-dispensing units, the new rules require that when operating at airports with elevations above 13,000 feet, dispensing units must be deployed automatically at cabin pressure altitudes no higher than 2,000 feet above the airplane’s maximum takeoff and landing altitude.