What happened
On July 22, 1971, a Ka-8 B glider, registration HB-663, was engaged in a cross-country flight intended to fulfill requirements for the FAI Silver Badge. After departing from Saanen airfield via aero-tow, the pilot completed a two-and-a-half-hour flight, reaching altitudes of approximately 2,600 meters near Marbach.
Upon reaching the target area near Schüpfheim, the pilot performed several circuits over the vicinity before selecting a small meadow west of the Kleine Emme river for an outlanding. The approach was conducted from the west. Due to the steep descent of the terrain, the aircraft touched down at a high rate of speed. During the landing roll, the glider bounced across two undulations in the uneven ground and, approximately 127 meters after the initial touchdown, the right wing struck a barn door.
The investigation
The investigation, conducted by the Swiss Transportation Safety Investigation Board in cooperation with the Lucerne Cantonal Police, examined the aircraft, the pilot's credentials, and the environmental conditions. The pilot held a valid glider license with towing privileges and had significant recent experience in similar aircraft types.
Technical inspections of the Ka-8 B revealed no mechanical defects or maintenance issues. The investigation also assessed the topography of the landing site, noting that while the valley floor east of the river offered much more suitable landing options, the pilot had instead chosen a field characterized by a steep slope and significant surface irregularities.
Findings
- The primary cause of the accident was the selection of an unsuitable landing site.
- The pilot failed to notice that the chosen field was situated at the foot of a steep slope, which necessitated a steep and high-speed approach.
- The unevenness of the terrain caused the aircraft to bounce during the landing roll, contributing to the loss of control.
- The impact with the barn resulted in a broken right wing and a broken spar on the left wing due to dynamic loading.
- A falling tile from the barn shattered the cockpit canopy during the collision.
There were no injuries to the pilot.