yawdemper

A yaw damper is an automatic control system in an aircraft that automatically applies rudder input to damp yawing motions of the airplane, most notably the Dutch roll. It uses sensors such as yaw rate gyros (and sometimes sideslip or other attitude signals) to detect yaw motion and generates corrective rudder deflections through hydraulic or electric actuators.

In operation, the yaw damper acts as a stabilization augmentation device within the aircraft’s flight control system. It can be part of the autopilot or a separate stability augmentation system. The control laws are designed to produce a small, continuous rudder movement proportional to the rate of yaw or to the observed yaw dynamics, counteracting sustained yaw oscillations without imposing large pilot-visible rudder commands. The system typically remains active in normal flight and can be disengaged by the pilot in some configurations.

Purpose and effects include reducing Dutch roll, limiting rudder activity required from the pilot, improving directional stability, and increasing passenger comfort. It also lowers structural loads from oscillatory yaw motions and helps maintain consistent flight characteristics in various flight regimes, including high speeds and swept-wing configurations.

Implementation varies by aircraft. Yaw dampers are common on airliners and many business jets, where they are integrated with the flight control system, and on some light aircraft as an optional or basic stabilization feature. A failure or disengagement can result in increased yaw instability and added pilot workload, and modern systems are designed to provide graceful degradation.