What happened
On July 7, 1963, a Pilatus Porter PC-6, registration HB-FAO, was performing a series of shuttle flights to transport members of the Biel section of the Swiss Alpine Club to a mountain hut. The mission, operated by ALPAR A.G., involved two taxi flights to the Oberaarjoch at approximately 3,270 meters altitude. While the initial landing at 07:40 was successful, the second attempt at 09:23 resulted in an incident.
Upon landing on the western slope of the pass, the heavily loaded aircraft failed to stop on the small plateau. Instead, the plane began to slide toward the Oberaar Glacier. The pilot attempted to execute a go-around; however, the engine reportedly did not respond immediately. As the aircraft veered to the right, the pilot maneuvered the plane uphill to prevent further sliding, using full power to arrest the movement. During this maneuver, the left wingtip made contact with the ground.
The investigation
The investigation examined the aircraft's configuration, noting it was equipped with a wheel-ski combination and was operating within weight and balance limits. The weather at the time of the second landing included convective clouds and moderate thermal turbulence near the cliffs, with winds of 15–20 knots at higher altitudes and potential downdrafts over the glacier.
Findings
Investigators determined that the accident was caused by a glacier landing that was too long for the available space. The heavy weight of the aircraft in difficult terrain made the landing particularly challenging. The investigation also noted that the pilot's attempt to perform a go-around was complicated by the terrain, as the path for such a maneuver required flying at an angle to the slope to avoid crevasses, and was further hindered by the reported delay in engine response.
Safety action
There were no injuries to the pilot or the seven passengers. The aircraft sustained significant damage to the left landing gear strut and ski, along with minor damage to the left wing and aileron.