Evaluation of a Novel Adaptive Thresholding and Trend Alert Generation Technology on a HUMS Equipped Fleet

The US Army Condition Based Maintenance Program has utilized static thresholding techniques to monitor the con-dition of gearboxes, bearings, and shafts on nearly 2000 aircraft over the last decade. In some cases, vibration based diagnostics thresholds do not produce the targeted detection or accuracy rates prescribed by Aeronautical Design Specification 79C. The US Army Aviation Engineering Directorate has evaluated a dynamic thresholding technique produced by HUMAWARE. This paper discusses the selection of a ground truth data set for this evaluation and presents the results of the new technique when applied to a small fleet of Apache rotorcraft.