14 C.F.R. § 31.45 Fuel cells.
Title 14 - Aeronautics and Space
If fuel cells are used, the fuel cells, their attachments, and related supporting structure must be shown by tests to be capable of withstanding, without detrimental distortion or failure, any inertia loads to which the installation may be subjected, including the drop tests prescribed in §31.27(c). In the tests, the fuel cells must be loaded to the weight and pressure equivalent to the full fuel quantity condition. [Amdt. 31–3, 41 FR 55474, Dec. 20, 1976]
Title 14: Aeronautics and Space
PART 31—AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS
Subpart D—Design Construction
§ 31.45 Fuel cells.