The enemy is FA, CND, and RTOK (avionics testing)

Integrated diagnostic requirements of a modern avionic subsystem are identified. A conceptual integrated diagnostic approach to meeting these requirements is postulated. Its essential elements, layered onboard built-in test (BIT), flight-line BIT augmentation, depot automatic test equipment (ATE), and a diagnostic support information system are described. Modern maintenance concepts into which these must be embedded are outlined and discussed. Mechanisms for false alarm (FA), cannot duplicate (CND), and retest OK (RTOK) events are identified, and their adverse impact assessed using both historical data and analytical examples. Corrective approaches are identified and their potential effectiveness examined. Criteria for evaluating ID tradeoffs in this milieu are identified.<
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