[Code of Federal Regulations] [Title 14, Volume 1] [Revised as of January 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR31.51] [Page 755] 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. 31.51 Ballast. Each captive gas balloon must have a means for the safe storage and controlled release of ballast. The ballast must consist of material that, if released during flight, is not hazardous to persons on the ground.