The Joint Strike Fighter (JSF) PHM concept: Potential impact on aging aircraft problems

The JSF Autonomic Logistics (AL) system is a new supportability concept that will enable the aircraft to be better utilized throughout the life of the platform, and at a lower cost as compared with legacy aircraft. Autonomic Logistics is, simply put, the automation of the logistics environment such that little human intervention is needed to engage the logistics cycle. Actions that will be automated within the JSF supportability concept include maintenance scheduling, flight scheduling, ordering spare parts, and the like. The cornerstone of Autonomic Logistics is an advanced diagnostic and Prognostics and Health Management (PHM) system. The PHM provides the data, information, and knowledge for initiating the AutoLog chain of events. PHM is the ability of the aircraft to do fault detection (FD), fault isolation (FI), and accommodation real-time on-board the aircraft. Along with this FD/FI capability, some of the other facets of PHM include fault prediction on selected components. parts life usage tracking, fault filtering and reporting, and recommended action to the pilot only when action is necessary. It is intended that in most cases, maintenance actions and lifing decisions will be based on the actual material condition of the equipment components. The proposed architecture of this PHM concept includes a hierarchical approach where data begins at the sensor level and is transported up to area reasoners that turns this data into information about a particular subsystem. From the area reasoner, the information is then passed up to a top level Air Vehicle Reasoner where subsystem information is then fused to give knowledge about the health of the entire air vehicle. Additionally, many of the technologies that are being developed for the JSF PHM suite could be applied to legacy aircraft and would show significant benefits in respect to LCC and maintainability issues. In many cases, the capability of PHM sensors and prognostic technologies will enable the ability to "see" incipient faults in subsystem components very early prior to their progressing to final system failure. These capabilities will enable accurate useful life remaining predictions and more aggressive health management of assets. Through very accurate tracking of the life usage data for component parts, the JSF PHM and AL will be able to anticipate many problems that plague current legacy aircraft; giving a lead time to provide fixes before the actual problems become fleet wide and catastrophic. The PHM architecture will directly interface with the Joint Distributed Information System (JDIS), the information system that will enable Autonomic Logistics functions. The JDIS could automatically forward to the Original Equipment Manufacturer (OEM) data on problems that arise within the fleet, thus alerting them to a developing situation sooner, and enabling them to provide faster, cheaper fixes to these problems. With these safeguards in place, the JSF will put itself in a position to quickly react to ageing aircraft problems, increase sortie generation rates, decrease mean time to diagnose faults and failures as well as drastically decrease maintenance costs.