Gearbox is a mechanical power transmission device, most commonly used to get the mechanical benefits
in terms of speed and torque. The gearbox is made up of different types of gears assembled in a cascading order to
perform the intended task. Failure of any rotating component inside the gearbox will terminate the working condition
of the mechanical system associated with it. This causes interrupted services to the industries, which lead to expensive compensation. Especially, in an aircraft engine, it is used as an accessory drive, which provides power for hydraulic,pneumatic and electrical systems. This motivated to monitor the gearbox health condition. This paper presents a brief review of GHCM (gearbox health condition monitoring), gearbox faults, overview of time-domain features, frequency-domain features, time-frequency domain; feature extraction techniques, and fault classification techniques.The outcome of this study is to provide brief information regarding gearbox health condition monitoring
