The Directorate of Technical Development (DTD) was established by the UK Air Ministry in 1924 with a focus on research and application of emerging materials, technologies and processes for the Royal Air Force. It issued a series of DTD Standards until its functions were reorganised and absorbed after WW2 into Britain’s continuing defence research effort. DTD Standards persisted until being officially deemed obsolete in 1999.  Many interwar, WW2 and early jet age aircraft and engines use DTD specifications. Where a DTD Standard grew into extensive use, it was often promulgated as a British Standard. In general, new DTD Standards described newly invented and sometimes secret materials, while those that persisted in the DTD format in later years described rarely used but nevertheless important materials.


Where DTD Standards are revised, the later version will contain a sequential letter at the end of title, eg DTD36, DTD36B, DTD36C


DTD Standards are supported by an INDEX document, that often indicates a Standard’s later adoption as an equivalent British Standard.


More DTD Standards are available. A small number are presented here and the work of scanning the balance continues. Where you wish to secure a copy of a DTD Standard not yet listed here, please use the Contact button to enquire if it is available.


Where you have copies of any old aircraft Standards please use the Contact button to arrange scanning and sharing.