The OH-58D Kiowa Warrior helicopter has been a workhorse for the U.S. Army for decades and is projected to continue to accrue flight hours for years to come as a highly capable platform applied against various mission profiles. The U.S. Army is interested in the implementation of condition based maintenance (CBM) for this platform to increase operational availability of the aircraft, reduce the required number of maintenance activities and increase the inspection interval period. The CBM methodology and these objectives are directly dependent upon the capability of the health and usage monitoring system and its ability to detect diagnose and provide an estimate of remaining useful life (RUL). The Applied Research Laboratory at The Pennsylvania State University (ARL Penn State) has developed prognostic technologies for helicopter electrical power systems that can be integrated into an existing on-board Health and Usage Monitoring System (HUMS). The goal of the program was to develop a capability to monitor, detect and provide an estimated remaining useful life RUL for the starter/generator, battery and power inverter. The focus of this effort was to develop technologies that provide actionable prognostic information for forecasting part replacement and to extend existing time and usage-based maintenance intervals.