VC10 Triple Yaw Damper Indicator

A yaw damper is a device used on many aircraft (usually jets and turboprops) to damp (reduce) the rolling and yawing oscillations known as the Dutch roll mode. It consists of yaw-rate sensors and a processor that provides a signal to an actuator connected to the rudder. The use of a yaw damper helps provide a better ride by preventing the uncomfortable yawing and rolling oscillation. On some aircraft it is mandatory for the yaw damper to be operational at all times during flight above a specified altitude.

Modern digital yaw dampers are part of an integrated digital autopilot system. They use accelerometers and rate sensors to determine the aircraft's motion. It then runs the numbers through special algorithms to determine what rudder inputs need to be made in order to damp any Dutch roll and to coordinate a turn. It then provides those rudder commands to a servo or hydraulic system which operates the rudder. The yaw damper is also known as a Stability Augmentation System.