Incident Overview
A flight instructor and a pilot were conducting a landing when the instructor decided to demonstrate adverse yaw. During the landing roll, the instructor maintained control of the ailerons and the pilot maintained control of the rudder. The instructor applied left aileron input, which caused the airplane to drift to the right. In response, the pilot applied left rudder, but the airplane continued drifting right and turned approximately 90 degrees from the runway heading. As the airplane turned right, the left wingtip contacted the ground, resulting in substantial damage to the left wing.
Details
The flight instructor intended to demonstrate the effect of adverse yaw during the landing. The specific sequence of control inputs led to an uncommanded turn during the ground roll. Despite the pilot's corrective rudder input, the airplane's deviation from the runway heading could not be corrected. The ensuing ground contact with the left wingtip caused structural damage.
Probable Cause
Not specified in the source.