Which control surface is primarily responsible for yaw motion?

• A. Rudder
• B. Aileron
• C. Elevator
• D. Spoilers

Answer: (A)

Yaw is the rotation of an airplane around its vertical axis, turning the nose left or right. The surface that produces the needed side force at the tail is the rudder, a movable vertical surface on the tail. When you deflect the rudder, air is pushed to one side, creating a yawing moment that makes the nose swing toward that side. The elevator controls pitch (nose up/down about the lateral axis), and the ailerons control roll (wing bank about the longitudinal axis). Spoilers mainly reduce lift and can affect yaw only as a secondary effect in some configurations, but they are not the primary device for yaw control. So the rudder is the component specifically designed to produce yaw motion.