Regulations last checked for updates: Feb 06, 2026

Title 14 - Aeronautics and Space last revised: Dec 19, 2026
§ 125.143 - Firewalls.

Each engine, auxiliary power unit, fuel-burning heater, or other item of combusting equipment that is intended for operation in flight must be isolated from the rest of the airplane by means of firewalls or shrouds, or by other equivalent means.

authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44705, 44710-44711, 44713, 44716-44717, 44722
source: Docket 19779, 45 FR 67235, Oct. 9, 1980, unless otherwise noted.
cite as: 14 CFR 125.143