Maintainability verification testing is conducted
during Phase I of the overall system life cycle as defined in Appendix
E. Other maintainability testing (i.e., demonstration and evaluation)
follow verification testing during subsequent phases of the system life cycle.
Figure B-1 provides a time phased chart for the three kinds of maintainability
testing discussed in this appendix. Each of the life cycle phases shown in the
figure are defined in detail in Appendix
E , Phasing of Maintainability Elements.
Figure B-1 - Time Phasing of Maintainability
The effort to verify maintainability parameters that are developed during
Phase 0 (e.g., predicted values of MTTR), is incremental in nature commencing
with initial design and continuing through hardware development from
components to the configuration item. The basic objectives of maintainability
- To verify and update the contractor's
- To ensure economical correction of design
deficiencies and to provide assurance that maintainability requirements will
be achieved and demonstrated, if required, by performing early in the design
process, maintainability verifications such as limited low confidence
maintainability tests, time-motion measurements or such other tests as may
be proposed by the system developer.
- To provide progressive assurance that the maintainability requirements
can be achieved and demonstrated and that elements of the integrated support
plan directly related to maintainability are valid.
Maximum use should be made of data resulting from
maintenance performed in conjunction with such tests as development,
prototype, mock-up, qualification, and reliability tests. In this respect,
collection of maintenance task data must be planned for and coordinated with
other disciplines. (See Section 4.5
of this handbook for a discussion of maintainability data elements to be
collected as part of a Failure Reporting, Analysis and Corrective Action
System [FRACAS]). Further, specific maintenance tasks used in development of
the maintainability model and prediction must be clearly defined such that
when failures occur during development testing that result in a specific
maintenance task, the maintenance time can be compared to that used in the
prediction model. This must be done for both preventive (as applicable) as
well as corrective maintenance tasking.