Onboard diagnostics of avionics for fault tolerance and maintenance

Summary form only given. Emerging modular avionics systems will require excellent onboard fault diagnosis, both to support flight critical functions and to provide for cost effective maintenance. The approach to fault isolation discussed makes use of multiple indications of failures, known as failure signatures or syndromes. A computer-aided design tool that can analyze the architecture and generate syndrome data for inclusion in embedded software algorithms has been developed. This tool performs automatic failure dependency analysis using as input a graphical schematic of the system to be analyzed. A further complication arises with the syndrome approach when detection tests fail to operate correctly. A method of mitigating this problem using partial pattern matching techniques on the pattern of test failure indication has also been developed. Other benefits of this approach are outlined.<>