Which control surface is primarily used to roll the aircraft?

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

Answer: (C)

Roll involves rotating the airplane about its longitudinal axis, so the surface that mainly controls it is the ailerons. Each wing has an aileron, and they move in opposite directions: when you move the control stick to one side, one aileron goes up and the other goes down. This creates more lift on one wing and less on the other, making the aircraft roll toward the wing with the upgoing aileron. Rolling into a bank is how you initiate a turn. The rudder governs yaw (nose left or right about the vertical axis), the elevator controls pitch (nose up or down about the lateral axis), and flaps mainly increase lift during takeoff and landing, not roll control.