US Patent 10037040 Stability and control augmentation system

A Stability and Command Augmentation System (SCAS) for an aircraft, the SCAS including, a first input shaft providing a first rotational input; a second input shaft providing a second rotational input; and a device for summing the first and second rotational inputs to give a rotational output for controlling an actuator. A method of operating a SCAS on an aircraft, the method including providing a pilot input order in the form of a rotating first shaft, providing an augmentation input order in the form of a rotating second shaft, summing the rotation of the pilot input order and the augmentation input order to give an output order; and using the output order to control an actuator.