Which control input primarily affects yaw motion of the aircraft?

• A. Cyclic stick
• B. Collective lever
• C. Tail rotor pedals
• D. Throttle

Answer: (C)

Yaw motion in a helicopter is a rotation about the vertical axis, controlled mainly by the anti-torque system. In a single-rotor helicopter, the engine spin of the main rotor creates a torque that would turn the fuselage in the opposite direction. The tail rotor provides the counter-torque, and changing its thrust changes the helicopter’s heading. The pedals adjust the pitch of the tail rotor blades, increasing or decreasing that thrust to yaw left or right.

Cyclic stick tilts the rotor disk to pitch or roll the aircraft, not to rotate around the vertical axis. The collective lever changes the overall lift of the rotor blades, affecting altitude and climb or descent, but not the heading. Throttle changes engine power and rotor speed, which can influence performance and overall torque somewhat, but the direct, primary control of yaw is the tail rotor pedals.