Landing gear drive system and method

A method of operating a drive system to rotate a wheel of a landing gear about a wheel axis, the drive system including:

• a drive assembly including an input gear rotatable about an input axis by an input shaft;
• an engagement assembly including a first intermediate gear meshed with the input gear and rotatable about a first intermediate axis by a first intermediate shaft and a first drive pinion mounted on the first intermediate shaft and arranged to rotate in tandem with the first intermediate gear, the engagement assembly being pivotable about the input shaft relative to the drive assembly;
• a locking device which is engageable to prevent rotation of the first intermediate gear about the first intermediate axis;
• and a driven gear attached to the wheel so as to be capable of rotating the wheel about the wheel axis, wherein one of the first drive pinion and the driven gear comprises a sprocket and the other of the first drive pinion and the driven gear comprises a series of rollers arranged to form a ring, each roller being rotatable about a roller axis at a fixed distance from an axis of rotation of the drive pinion or driven gear, respectively, the method including the steps of:
• engaging the locking device to prevent rotation of the first intermediate gear about the first intermediate axis;
• applying a torque to the input gear in a first direction to thereby pivot the engagement assembly about the input axis in the first direction to a position in which the first pinion gear is meshed with the driven gear and the locking device is disengaged;
• and
• continuing to apply the torque to the input gear in the first direction to rotate the driven gear in the first direction and thereby rotate the wheel about the wheel axis in the first direction.