14 C.F.R. § 125.147 Cowling.
Title 14 - Aeronautics and Space
(a) Cowling must be made and supported so as to resist the vibration, inertia, and air loads to which it may be normally subjected. (b) Provisions must be made to allow rapid and complete drainage of the cowling in normal ground and flight attitudes. Drains must not discharge in locations constituting a fire hazard. Parts of the cowling that are subjected to high temperatures because they are near exhaust system parts or because of exhaust gas impingement must be made of fireproof material. Unless otherwise specified in these regulations, all other parts of the cowling must be made of material that is at least fire resistant.
Title 14: Aeronautics and Space
PART 125—CERTIFICATION AND OPERATIONS: AIRPLANES 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
Subpart E—Special Airworthiness Requirements
§ 125.147 Cowling.
