Code of Federal Regulations

Title 14 - Aeronautics and Space
Volume: 1Date: 2023-01-01Original Date: 2023-01-01Title: Section 25.959 - Unusable fuel supply.Context: Title 14 - Aeronautics and Space. CHAPTER I - FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION. SUBCHAPTER C - AIRCRAFT. PART 25 - AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES. Subpart E - Powerplant. - Fuel System.
ยงโ€‰25.959 Unusable fuel supply. The unusable fuel quantity for each fuel tank and its fuel system components must be established at not less than the quantity at which the first evidence of engine malfunction occurs under the most adverse fuel feed condition for all intended operations and flight maneuvers involving fuel feeding from that tank. Fuel system component failures need not be considered. [Amdt. 25โ€“23, 35 FR 5677, Apr. 8, 1970, as amended by Amdt. 25โ€“40, 42 FR 15043, Mar. 17, 1977]