Ministry of Defence
Defence Standard 00-42 Part 1
Issue 2 Publication Date 15 February 2008
Reliability and Maintainability
(R&M) Assurance Activity
Referenced standards and/or methodologies
Status (as a standard document)
Replaced/Superseded by document(s)
This standard is raised to Defence Standard 00-42, Part 1 Issue 2 to update its content.
This standard supersedes the following:
Defence Standard 00-42, Part 1 Issue 1
One-shot devices and one-shot systems, either electronic, mechanical or structural, by definition, cannot be
fully tested prior to use because testing in the full mode of operation usually results in their total or partial
destruction; or an irreversibility of a discrete part. One-shot devices for military applications are,
conventionally, stored for long periods, often in excess of 10 or 20 years and, during this time, may be
transported between and stored in different climatic conditions before being finally expended in the manner
for which they are designed.
Reliability can, therefore often only be demonstrated statistically by sampling some of the items and fully
testing these. This leads to: a need to identify discrete parts of production by batch or lot; a requirement to
apply sampling knowledge; and the necessity to apply viable probability theory to deduce correct statistical
inferences. The requirements of Def Stan 00-40, Part 1 in whole or tailored, can be made contractual during
the design and development stages of the acquisition cycle however it will need to be conducted with a
detailed understanding of the solution and it’s associated R&M specification.