14 CFR § 125.143 - Firewalls.

---
identifier: "/us/cfr/t14/s125.143"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 125.143 - Firewalls."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "125.143"
section_name: "Firewalls."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "G"
subchapter_name: "AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS"
part_number: "125"
part_name: "CERTIFICATION AND OPERATIONS: AIRCRAFT HAVING A SEATING CAPACITY OF 20 OR MORE PASSENGERS OR A MAXIMUM PAYLOAD CAPACITY OF 6,000 POUNDS OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44705, 44710-44711, 44713, 44716-44717, 44722."
regulatory_source: "Docket 19779, 45 FR 67235, Oct. 9, 1980, unless otherwise noted."
cfr_part: "125"
---


# 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.