[Code of Federal Regulations] [Title 14, Volume 1] [Revised as of January 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR31.31] [Page 762] 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. 31.31 General. The suitability of each design detail or part that bears on safety must be established by tests or analysis.