1966 Piper PA-18 HB-OLB Mountain Collision in Glarus

Accident Overview and Investigation Findings On the morning of Sunday, 24 July 1966, a Piper PA-18 Super-Cub, registration HB-OLB, was conducting free passenger flights from Mollis airfield to the Planurahütte. During the second flight, the aircraft collided with a rock wall on the north flank of the Bifertenstock, near the Bifertenlücke, while apparently attempting to cross a ridge saddle from the Glarnerland into the Vorderrheintal. The aircraft was destroyed, and all three occupants—the pilot and two passengers—were killed. The Swiss Federal Aircraft Accident Investigation Commission concluded that the accident was most likely caused by the pilot using an inappropriate tactic while attempting to cross a ridge saddle under unfavorable conditions. ## Aircraft, Crew, and Operational Context The aircraft was a 1964 Piper PA-18 Super-Cub, serial number 18-3096, powered by a 150 hp Lycoming O-320-A engine. It was owned and operated by the pilot, who held a private pilot license and a special permit for mountain landings. The pilot had approximately 677 flight hours and 2,739 landings, including 1,209 mountain landings. The two passengers were members of the Tödi section of the Swiss Alpine Club and had no flight experience. The aircraft was reported to be in excellent condition, with no evidence of mechanical failure. ## Search, Recovery, and Site Evidence The accident was not witnessed. The pilot made a position report over the Bifertengletscher about half an hour after takeoff, after which the aircraft was lost. A search began the same evening, and the wreckage was discovered on 26 July 1966 by an army helicopter on the Bifertenfirn. Recovery was complicated because much of the white aircraft debris was covered by a snow avalanche triggered by the crash. The main wreckage field was found on a steep glacier slope at 2,480 m, in the fall line of the Bifertenlücke at the foot of a rock wall about 500 m high. Sliding tracks in the snow indicated the initial impact occurred about 600 m higher, near the Bifertenlücke, where the aircraft struck a rock, slid down a steep firn field, triggered a small avalanche, and then fell over the rock wall onto the glacier.