In some implementations, a controller may cause a gearbox coupled to a rotor to shift between a first gear ratio and a second gear ratio one or more times. The controller may obtain a first set of position data that identifies respective first positions of a gear selector of the gearbox for each shift to the first gear ratio, and a second set of position data that identifies respective second positions of the gear selector of the gearbox for each shift to the second gear ratio. The controller may determine a first calibrated position of the gear selector for a shift to the first gear ratio based on the first set of position data and a second calibrated position of the gear selector for a shift to the second gear ratio based on the second set of position data.