202.1 PURPOSE. To
incorporate testability design practices into the design of a system or
equipment early in the design phase and to assess the extent to which
testability is incorporated.
Institute testability design concepts as an integrat part of
the system or equipment design process. Guidance is provided in Appendix
A, paragraph 50.6, on the use of these concepts.
Incorporate appropriate testability design concepts into the preliminary
design for each item. Develop BIT hardware, software and firmware as an
integral part of the design effort.
and evaluate the selected testability concepts of the system or equipment
design in a qualitative manner to ensure that the design will support the
required level of testing. Conduct an analysis of the inherent (intrinsic)
testability of the preliminary design. The analysis identifies the presence
or absence of hardware features which facilitate testing and identifies
problem areas. The method of Appendix B
shall be applied to each item identified for inherent testability assessment
by the requiring authority. The inputs required by Appendix B shall be determined by the
performing activity and approved by the requiring authority.
the design, as necessary, until the inherent testability equals or exceeds
the threshold value. If the performing activity concludes that achieving the
threshold is not possible or cost effective, but that the fault detection
and fault isolation requirements will be met, the performing activity shall
provide supporting data for review by the requiring authority.
a methodology for Task
203 for predicting fault detection and fault isolation performance
or equipment design data.
Identification of items to be included in inherent
testability analysis (Appendix B).*
202.3.3 For each
item, inherent testability threshold value to be
achieved. Guidance for establishing a threshold value is given in Appendix A,
or equipment design which incorporates testability features. (202.2.1,
202.2.2 and 202.2.4)
Description of testability design tradeoffs and testability features
selected for implementation; documented in accordance with DI-T-7199.
(202.2.2 and 202.2.4)
202.4.3 For each
item, assignment of weighting factor and scoring method for each testability
criterion (Appendix B). (202.2.3)
testability assessment; documented in accordance with DI-T-7199.
Description of methodologies, models and tools to be used in
203; documented in accordance with DI-T-7199. (202.2.5)
*To be specified by the requiring