14 C.F.R. § 25.959 Unusable fuel supply.
Title 14 - Aeronautics and Space
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. 25–23, 35 FR 5677, Apr. 8, 1970, as amended by Amdt. 25–40, 42 FR 15043, Mar. 17, 1977]
Title 14: Aeronautics and Space
PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart E—Powerplant
Fuel System
§ 25.959 Unusable fuel supply.
