A review of vibration-based techniques for helicopter transmission diagnostics

Over the past 25 years, much research has been devoted to the development of Health and Usage Monitoring (HUM) systems for rotorcraft gearbox and drivetrain components. The promise of HUM systems is the ability to provide accurate information regarding the condition of various flight critical components. This paper reviews the state of the art in vibration-based helicopter transmission diagnostics. The development of various damage detection techniques is discussed from a historical perspective, and the ability of these techniques to detect damage in helicopter transmissions is reviewed. Emerging research trends suggest that improvements in signal processing, sensor development and individual-tooth mesh waveform modelling could improve the performance of current and future helicopter transmission diagnostics.