This International Standard lays down the general specifications for constant displacement hydraulic motors to be installed in aircraft, which transform hydraulic power into mechanical energy in the form of a rotational torque. Primary and secondary function motors (see clause 3) are covered in this International Standard; actuators with internal rotation angle limits and low-speed motors are not covered in this International Standard. This International Standard shall be used in conjunction with the detail specification particular to each application. NOTE — A schematic summary is provided in annex A for easy reference to the contents of this International Standard.