This specification describes the procedure governing the approval of proprietary materials and processes. It also includes Appendices listing all materials and processes approved under its terms together with the name and address of the manufacturer or proprietor, the trade name of the material or process, if any, and the approval serial number.

The terms ‘‘proprietary material" and "proprietary process" for the purpose of this specification are applicable to materials or processes not covered by a BS aerospace, DTD or other specification approved by the procurement Executive, Ministry of Defence.

As approval under this specification covers proprietary materials and processes, details of which may be divulged in confidence to the Design Authority and/or Procurement Executive, Ministry of Defence, no specifications for the individual items are available and enquiries should be addressed to the manufacturer or proprietor concerned.