Fault-Tolerant System Analysis: Imperfect Switching and Maintenance

摘要

This final report presents the results of research into two important areas of concern for fault-tolerant avionics systems: testability analysis and innovative repair policies. The algorithms developed from this research have been included in the Mission Reliability Model (MIREM) and verified by comparison with known results from several Integrated Communication, Navigation, and Identification Avionics architectures. The purpose of the testability analysis was to develop techniques for assessing the impact of imperfect switching on the overall reliability of fault-tolerant avionics. A method of quantifying the effects of undetected errors and false alarms has been developed and included in MIREM. Under the next phase of the program, three repair statistics were identified: Mean Time To Repair, Mean Time Between Maintenance Actions, and Inherent Availability. These were used to define four alternative repair policies: immediate repair, deferred repair, scheduled maintenance, and repairat degraded level. Also included in MIREM as model outputs, these four options offer greater flexibility in evaluating and developing avionics designs.