Rudder stabilizes which stability?

• A. Directional
• B. Lateral
• C. Longitudinal
• D. Vertical

Answer: (A)

Rudder primarily affects directional stability, the tendency of the aircraft to maintain or return to a straight path about the vertical axis. When the airplane begins to yaw, the vertical tail and rudder create a restoring yawing moment that opposes the deviation, helping to realign the nose with the flight path and dampen the sideslip. In practice, using the rudder to counteract yaw is essential for coordinated flight and for stabilizing the aircraft in crosswinds or when there’s uncoordinated input. Lateral stability deals with roll about the longitudinal axis (managed by dihedral, wing shape, and ailerons), and longitudinal stability deals with pitch about the lateral axis (managed by the horizontal stabilizer and elevator).