Dynamic fault monitoring and fault-based decision making in vehicle health management systems

Abstract

Vehicle Health Management Systems (VHMS) are used throughout commercial, military, and aerospace platforms to assess the current operational status of individual assets and entire fleets. One of the most common functions within most VHMS implementations is the collection and reporting of fault conditions and trouble codes. The management of this fault data, particularly its representation to a user, has become more complex as built-in-test (BIT) and fault detection sophistication have continued to grow. Often times, multiple fault indications or diagnostic trouble codes may exist simultaneously as the result of the failure of a single line replaceable unit (LRU). This can result in operator confusion that is compounded by the appearance of nuisance faults, which may appear even though no failure is present. This paper describes a dynamic subscription-based method for simplifying the presentation of fault data as implemented on the Diagnostics And System Health (DASH) VHMS. The implementation described provides an efficient solution for dynamic fault monitoring and fault-based decision making, which can identify and mask nuisance and secondary fault conditions. By analyzing reported faults, LRU data, and platform events, DASH can automatically filter a fault list to display high priority and primary fault conditions, thus assisting maintenance personnel in quickly identifying the primary failure mode in an environment where multiple fault indications exist simultaneously. The DASH system further expands on this capability by automatically isolating certain failure modes to reduce their ambiguity groups to a single failed LRU. DASH can also reduce operator confusion by limiting the appearance of nuisance fault codes to situations in which the fault condition they represent has been confirmed. This results in more efficient diagnostic troubleshooting and more focused maintenance activity, thus reducing a system's mean time to repair (MTTR).