Rudder

The rudder is the movable control surface on the vertical tail that controls yaw around the vertical axis. It is normally operated with the foot pedals and is used to keep the aircraft coordinated, especially in turns, crosswind take-off and landing, and when countering asymmetric effects. Too much or abrupt rudder can cause unwanted sideslip or yaw. You use it with smooth pedal inputs and coordinate it with aileron as needed.