10.8 System Reliability
Specification, Prediction and Demonstration
presented in great detail methods for specifying, predicting, and
demonstrating system reliability.
The methods and design procedures presented in Section
7 are directly applicable to system reliability parameters for the case of non-maintained
systems, e.g., missiles, satellites, “one-shot” devices, etc.
For maintained systems, the methods and procedures presented in
and  are directly applicable to system maintainability parameters.
When these are combined with the methods of Section
7 and the appropriate sections of this section, they provide a complete
capability for specifying, predicting, and demonstrating most system R&M
parameters, as well as trading them off to maximize system availability or
some other appropriate effectiveness parameter at minimum cost.
Perhaps the only area that may need some further discussion is
availability demonstration methods. At the present time no accepted test plans
exist for steady state availability; however, MIL-HDBK-781 describes two
availability demonstration tests; one for fixed sample size, the other a fixed
time test. The tests are based upon a paper presented at the 1979 Annual
Reliability and Maintainability Symposium (Ref. ). The
paper also provides a theoretical discussion of sequential test plans, but no
standardized plans are presented. Program managers or R&M engineers who
wish to consider using sequential availability tests should consult the
referenced paper. The proposed demonstration plans are described in the