Which stability describes the aircraft's stability about its lateral axis?

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

Answer: (A)

Pitch stability is the aircraft’s tendency to return to its set pitch after a disturbance. The lateral axis runs from wingtip to wingtip, so rotations about it are nose-up or nose-down motions. When the aircraft has positive longitudinal stability, a nose-up disturbance creates restoring moments that push the nose back toward level flight, and a nose-down disturbance produces moments that bring the nose back up. The horizontal stabilizer provides the main restoring moment, and its effectiveness is influenced by the center of gravity position and tail design. This stability about the lateral axis is distinct from stability about the longitudinal axis (roll) and about the vertical axis (yaw).