Pitch is defined as the motion of the longitudinal axis about which axis?

Pitch refers to the rotation of an aircraft about its lateral axis. This axis runs from wingtip to wingtip, allowing the nose of the aircraft to move up or down relative to the horizon. When an aircraft pitches, it climbs or descends, affecting its angle of attack and, consequently, its flight dynamics.

Understanding the relationship between the axes is crucial in aviation. The longitudinal axis runs from the nose to the tail, while the vertical axis intersects the aircraft from top to bottom. The term "horizon" describes the visual reference point rather than an axis of rotation. Therefore, the lateral axis is indeed the correct choice, as it directly relates to the motion of pitch, distinguishing it from the other axes involved in an aircraft's movement.