[2] The purpose of the yaw damper is to make an aircraft easier to fly by eliminating the necessity for the pilot to act against such tendencies.
[1] A yaw damper may remove the necessity for a pilot to make any contact with the rudder pedals during turns on a range of aircraft, including jet-powered ones.
[2][3] Some aircraft, such as the Boeing 727 and Vickers VC10 airliners, are fitted with multiple yaw damper systems due to their operation having been deemed critical to flight safety.
[1][5] On a single-engine aircraft, the system is particularly useful at addressing the tendency to 'fishtail', smoothing out the left–right movements of the vertical stabilizer (fin), increasing ride comfort.
[2][1] Equally, the system is commonly disengaged prior to landing, as it could inhibit the control authority to the pilot at the critical moment of touchdown.