The Yaw Damper System provides airplane stabilization about the yaw axis. The Yaw Damper minimizes dutch roll during flight by providing rudder displacement proportional to, and opposing, the yaw rate of the airplane.
The Yaw Damper System is engaged by a switch on the flight control module through the AFC accessory unit (or IFSAU). When the system is engaged, a rate gyro in the coupler senses yaw rate of the airplane. The yaw rate signal is processed to generate a command to the rudder power control unit which moves the rudder. The signal is translated from electrical to mechanical in the rudder power control unit by a transfer valve. Position feedback is accomplished by an LVDT. A position indicator in the flight compartment indicates rudder movement due to yaw damper inputs. There is no feedback to the rudder pedals since a series hydraulic actuator is used in the power control unit