Abstract:
Structural usage and loads monitoring can enhance safety, by identifying unusual usage patterns by individual aircraft or sub-fleets (e.g. operators, missions, or locations), and provide benefit to operators by enabling extended retirement times of life-limited components. While flight regime recognition (RR) algorithms have been demonstrated and partially validated, the use of existing onboard generic RR software provided in legacy Health and Usage Monitoring Systems (HUMS) remains a challenge for achieving airworthiness approval of retirement time extensions using archived fleet data in compliance with existing guidance, such as the U.S. Army ADS-79E Handbook for Condition-Based Maintenance. The U.S. Army and Sikorsky Aircraft, a Lockheed Martin Company, conducted a joint Fatigue Life Management (FLM) project to configure, validate, and apply processes and methods for extending the retirement times of six high-value components for the Army's Black Hawk helicopter fleet, which is equipped with a state-of-the-art HUMS, known as the Integrated Vehicle Health Management System (IVHMS). A RR post-processing process for addressing key technical challenges associated with the use of legacy onboard RR software was configured and verified against existing UH-60 flight test data. These post-processing methods were then applied to a two year population of UH-60 fleet data to calculate usage statistics for individual aircraft within several sub-fleet populations associated with either different global deployment locations and/or missions. The fleet statistics were then used by the Army Aviation Engineering Directorate (AED) to establish a conservative update to the existing usage spectrum, which was applied by Sikorsky to calculate updated retirement times. The focus of this paper is on the successful configuration and verification of RR software used in compliance with ADS-79E to establish UH-60 A/L/M IVHMS fleet usage statistics. A companion paper, also published within proceedings of the AHS 74th Annual Forum, provides details on using the fleet statistics to define an updated UH-60 usage spectrum.