220.127.116.11 Fault isolation
time. During maintenance actions using BIT or off-line test, the
time to fault isolate is often the largest and most unpredictable element of
repair time. The testability program should not only attempt to reduce the
fault isolation time but should also try to provide accurate predictions of
fault isolation times to maintenance planners per Task 205 of MIL-STD-470A.
The fault isolation time may be expressed as an average time, a maximum time
(at some percentile), or both. The time is based not only on the length of the
diagnostic test sequence but also must include an estimation of time
required for any manual intervention (e.g., the use of a sequential
substitution fault isolation procedure).