ED Decision 2009/005/R

1. The suitability and durability of materials used for parts, the failure of which could adversely affect safety, must
   1. be established by experience or tests; and
   2. meet approved specifications that ensure their having the strength and other properties assumed in the design data. (See AMC 31HB.33(a)(2))
2. Envelope materials must be shown not to support continued burning if ignited by the heater when the balloon is inflated or in flight.

ED Decision 2009/005/R

Approved specifications here should be taken as being those produced by the applicant or those meeting internationally recognised standards as defined applicable in the type design data. Material specifications should be those contained in documents accepted either specifically by the Agency or by having been prepared by an organisation or person which the Agency accepts has the necessary capabilities. In defining design properties these material specification values should be modified and/or extended as necessary by the constructor to take account of manufacturing practices (for example method of construction, forming, machining and subsequent heat treatment). Also the effects of environmental conditions, such as temperature and humidity, expected in service should be taken into account.

→ CS 31HB.35