Continued Evaluation and Spectrum Development of a Health and Usage Monitoring System

摘要

This report describes the results of a research project to evaluate structural usage monitoring and damage tolerance methodology using data collected on a Bell Model412 helicopter that was equipped with a health and usage monitoring system (HUMS). The helicopter was operated by Petroleum Helicopters Inc., from its base in Morgan City (UMMC). The usage spectrum data from the UMMC were compared to certification data and to data from previous HUMS studies. The previous HUMS studies included the Atlanta short haul mission (ASHM), which was considered severe usage because it involved many short maneuvering flights to provide pickup and delivery services at the Olympics, and the Gulf Coast mission (GCM), which was considered mild usage because it primarily involved long cruise flights. The results of the different missions showed that usage monitoring could provide benefits in extending retirement times or inspection intervals compared to those set during certification, especially if high- and low-altitude effects are considered. In addition to usage monitoring evaluations, simplified mini-HUMS approaches were reviewed that could potentially provide low-cost HUMS with high paybacks. Also, guidelines were developed for HUMS certification and qualification and for the integration of HUMS into the operator's maintenance program. These guidelines are also discussed in the report. Finally, the usage data that were collected were used to perform fatigue-life calculations and theoretical redesigns fo four selected rotor system components known as principal structural elements to meet damage tolerance requirements.