A method of engaging a drive system with a rotating wheel of an aircraft landing gear is disclosed. A motor is operated to apply torque to a pinion so the pinion rotates. An engagement command is issued to an actuator at an engagement time, and the actuator operates the actuator in response to the engagement command to move the pinion from a neutral position to a contact position in which it contacts a rotating driven gear at an initial contact time, the rotating driven gear being mounted to a rotating wheel of an aircraft landing gear; then after the initial contact time operating the actuator to move the pinion further to a meshing position where the pinion meshes with the driven gear. A centre-to-centre distance between the pinion and the driven gear reduces as the pinion moves to the contact position and to the meshing position.