{"data":{"id":"us/14-cfr-31.12","jurisdiction":"us","citation":"14 CFR 31.12","heading":"Proof of compliance.","body":"(a) Each requirement of this subpart must be met at each weight within the range of loading conditions for which certification is requested. This must be shown by—\n(1) Tests upon a balloon of the type for which certification is requested or by calculations based on, and equal in accuracy to, the results of testing; and\n(2) Systematic investigation of each weight if compliance cannot be reasonably inferred from the weights investigated.\n(b) Except as provided in § 31.17(b), allowable weight tolerances during flight testing are + 5 percent and −10 percent.","path":["Title 14—Aeronautics and Space","CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER C—AIRCRAFT","PART 31—AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS","Subpart B—Flight Requirements"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-14.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:20Z","sha256":"688633805fc458f3c4bfb87216c0dd35fcae2579d33561a37d35b886e03e0584","source_id":"us-cfr","stale":true,"prev":"us/14-cfr-31.1","next":"us/14-cfr-31.14"},"notice":"GroundRules: Original legal text. Not legal advice."}