[Code of Federal Regulations] [Title 14, Volume 1] [Revised as of January 1, 2007] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR31.45] [Page 766] TITLE 14--AERONAUTICS AND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 31_AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS--Table of Contents Subpart D_Design Construction Sec. 31.45 Fuel cells. 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 Sec. 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]