A hierarchical approach to system-level diagnostics (avionics)

A hierarchical approach to system-level diagnosis has been developed which sets aside the detailed physical knowledge of the system and analyzes the information flow through the system using information theory and dependency modeling. Diagnostic tests are considered information sources, and possible failures are considered conclusions. Tests are chosen from the model for evaluation on the basis of the amount of information they provide. Test results are then combined in a data fusion algorithm so that diagnostic conclusions may be drawn. This hierarchical approach can be applied to any level of system complexity. The techniques used in the hierarchical approach are embodied in the ARINC Research System Testability and Maintenance Program (STAMP), and have been applied to a large number of complex systems with outstanding results. System-level testability and fault isolation are discussed, and the successful uses of the STAMP analysis approach are summarized