AH-64D Main Transmission Accessory Drive Spur Gear Installation Fault Detections

The US Army has launched an aggressive program to implement Condition Based Maintenance on its rotary wing assets. Condition Based Maintenance takes advantage of technology developments in the areas of machinery monitoring, signal processing and fault modeling to reduce the cost of ownership through improved maintenance procedures. Documented reduction in maintenance burden, cost savings and increased safety through early detection of helicopter faults are an important step in justifying the program. This paper describes several instances of one type of fault detection in the accessory section of the main transmission of the AH-64D Apache with a serious flight safety impact.