What happened
On June 3, 1966, a Ka-6 glider, registration HB-634, was performing a landing in a field near Petit-Martel, Switzerland. During the final stages of the approach, the pilot observed a stake positioned in the landing area at the last moment. The stake was difficult to detect because it was obscured by tall grass.
In an attempt to avoid the obstacle, the pilot executed a maneuver to the left. However, during this evasive action, the low wing of the aircraft made contact with the ground, hindered by the thick vegetation. This contact resulted in a loss of control, causing the glider to crash into the field. The pilot sustained no injuries during the incident.
The investigation
The investigation focused on the circumstances of the landing and the visibility of obstacles within the landing site. The inquiry established that the primary obstacle was a stake that remained hidden from the pilot's view until the very end of the landing sequence due to the height of the surrounding grass.