What happened
On July 16, 1966, a Rhönlerche II glider, registration HB-576, was engaged in a dual instruction flight at the Birrfeld airfield in the Canton of Aargau. During the flight, the student pilot performed an evasive maneuver which resulted in the left wingtip making contact with the ground. This initial contact led to the aircraft striking the ground, causing substantial damage to the airframe.
The investigation
An investigation into the incident established that the contact with the terrain occurred as a direct result of the student pilot's maneuvering. The investigation examined the sequence of the flight and determined that the instructor, who was operating the aircraft in a dual-control capacity, was unable to intervene in time to prevent the wingtip from striking the surface.