A Model-Based Approach to MIL-STD-1553 Verification and Diagnosis

This paper describes an approach to production testing of the McDonnell Douglas Helicopter Company AH-64A Apache MIL-STD-1553 multiplex bus utilizing concepts derived from automatic testing and expert system technology. The increasing complexity of modern military aircraft systems requires the development of enhanced automation techniques for aircraft production, maintenance and operation. The Multiplex Expert System is designed as an intelligent assistant for Apache production test personnel to reduce the time and costs incurred during the production test and troubleshooting cycle. This project investigates the usefulness of t model-based reasoning applied to 1553 multiplex diagnostics and as a diagnostic technique for aircraft systems in general. A structural model of the Apache multiplex system has been implemented allowing the expert system to reason at a functional level about frequently encountered problems. This model provides the mechanism from which troubleshooting heuristics are automatically generated to guide the tester through a series of diagnostic steps until all failures have been isolated. Model-based reasoning is a promising technique for the domain of aircraft diagnostics not only on the manufacturing floor, but also in the field and in flight.