Wear Sensors for Pitch Control Bearing Condition Based Maintenance

Self-lubricating rotor blade pitch control bearings are critical to safe operation and fleet readiness. However, detecting bearing liner wear can be subjective and time consuming. Standard measurement techniques could lead to unsafe operational conditions or poor bearing life utilization. Excessive inspections, unplanned downtime and poor part utilization may be driven for safety and result in increased cost. New Hampshire Ball Bearings (NHBB) has developed a novel new approach that provides clear indication of when a bearing should be replaced. An embedded bearing liner wear sensor is connected to an Ultra High Frequency (UHF) passive Radio Frequency Identification (RFID) communication device to communicate bearing status to a hand held reader. Status of each individual bearing is reported. This new technology will allow operators and maintainers to conduct bearing maintenance when it is required by actual bearing condition instead of a fixed schedule based on Condition Based Maintenance (CBM) systems. Application specific and component functional testing on the wear sensor system (conducted at NHBB) shows wear performance similar to traditional blade pitch control applications with no impact to overall system operational capabilities. NHBB and Bell Helicopter are collaborating to introduce this technology on the Bell 525 with flight testing tentatively planned for 2017. Future work on this project will focus on aircraft and maintenance system integration.