Component Life Management Using HUMS Data and Probabilistic Structural Integrity

A Health and Usage Monitoring System (HUMS) records a large number of flight parameters that can be utilized for regime recognition and tracking of individual rotorcraft usage. The availability of this information from a fleet offers the additional opportunity to work with these large datasets within an Advanced Structural Integrity Framework (ASIF) developed to perform reliability-based design and maintenance, considering durability and damage tolerance. Probabilistic analytical techniques were explored using a sample of UH-60 Integrated Vehicle Health Monitoring System (IVHMS) fleet data that was analyzed for the horizontal stabilator in a case study to estimate the reliability associated with a specified component replacement time and inspection interval. Probabilistic sensitivity studies showed that the deterministic design and substantiation practices used for the horizontal stabilator very closely approximated the industry accepted reliability levels for fatigue and crack growth. The probabilistic methodology also effectively utilized the available IVHMS regime recognition output, but the reliability results depended greatly on assumptions used to describe statistical distributions of key random input parameters, especially loads, which were not available from the fleet data for this component. The ASIF was shown to be a powerful tool for reliability-based management of rotorcraft structural integrity. Further work is needed to confidently configure and fully exploit such methods.