14 C.F.R. § 121.261 Vent and drain lines.
Title 14 - Aeronautics and Space
All vent and drain lines and their fittings, that are located in a designated fire zone must, if they carry flammable fluids or gases, comply with §121.259, if the Administrator finds that the rupture or breakage of any vent or drain line may result in a fire hazard.
Title 14: Aeronautics and Space
PART 121—OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart J—Special Airworthiness Requirements
§ 121.261 Vent and drain lines.
