scope:

This Defence Standard specifies requirements for procedural and technical aspects and guidelines to be followed during development of equipment procured for the UK armed forces. 

The Standard provides a description of the principles of Testability and provides guidance on the related document content (usually Testability policy is part of the Project Reliability Programme Plan) and the ownership through the life of a system. The Testability policy is intended to be used throughout the procurement chain from prime contractor down to individual sub-contractors including suppliers of COTS (Commercial Off The Shelf) and GOTS (Government Off The Shelf) equipment. 

The activities required for the achievement of Testability will depend on the type and development stage of the equipment, and will be specific to each project. Significant variations may be noticed between mechanical, electro-mechanical, or electronic (with or without software) or combinations of these. Testability characteristics may be largely predetermined by state-of-the-art and/or COTS and GOTS. The guidelines given in this Defence Standard shall not be considered as being prescriptive in nature; they are generic and do not attempt to be exhaustive.

Fig 1 in this Part of the standard illustrates the process diagram that can be adopted in identifying the attributes to be considered at any stage of a project, and at any point in the hierarchy of the design, in order to maximise Testability of critical system functions.