14 C.F.R. § 23.954 Fuel system lightning protection.
Title 14 - Aeronautics and Space
The fuel system must be designed and arranged to prevent the ignition of fuel vapor within the system by— (a) Direct lightning strikes to areas having a high probability of stroke attachment; (b) Swept lightning strokes on areas where swept strokes are highly probable; and (c) Corona or streamering at fuel vent outlets. [Amdt. 23–7, 34 FR 13093, Aug. 13, 1969]
Title 14: Aeronautics and Space
PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES
Subpart E—Powerplant
Fuel System
§ 23.954 Fuel system lightning protection.