Although a formal test program to demonstrate testability features is not practical, full use must be made of all forms of other testing, including reliability demonstration tests and other development tests, to improve the testability design of the system. This requires, however, that the diagnostic system, such as BIT, be available prior to the testing taking place. Once again, close coordination between the individual(s) responsible for the diagnostic design and other disciplines within the IPD team is absolutely essential.
During all testing that includes diagnostics, all failures and the diagnostic system response to those failures, as well as the ability to detect and isolate faults using test support equipment, must be recorded and analyzed accordingly to identify problems and to develop corrective actions. This process includes collecting diagnostic performance data on both hardware and software faults. A training program should be instituted that disseminates to all individuals responsible for data collection the importance of testability information, and how to properly record such data. This form of verification and evaluation (i.e., using laboratory tests, development tests, etc.), as opposed to dedicated demonstration testing, is much more effective for testability features, as such testing provides a means for testing diagnostics for long periods of time without the need for unique diagnostic tests and extra assets.
Other methods regarding testability design and
testability improvement can be found in Appendix C , Design Guidelines.