Incident Overview
On November 25, 1965, a single-engine Piper PA-28-140 "Cherokee" with registration HB-OLD departed from Flughafen Kloten at approximately 15:15 local time. The pilot, a German citizen born in 1938, was flying solo under Visual Flight Rules (VFR). No specific route or destination was declared in the flight plan, although the intended duration was estimated at one hour and forty minutes.
Accident Reconstruction
The aircraft failed to return to Kloten as expected. After a search operation that initially covered areas from the Napf region to the Allgäu, debris was discovered on April 11, 1966, and positively identified on April 20, 1966, on the southeastern slope of the Goggeienberg in Toggenburg. The crash site was located at an elevation of 1,650 meters, approximately 10 to 15 meters horizontally from the mountain ridge. Witness reports allowed investigators to reconstruct a flight path totaling roughly 285 kilometers, which included circling over several towns before the final approach to the accident location.
Contributing Factors
The investigation identified severe weather conditions as a primary factor. At the time of the crash, strong foehn winds were present between altitudes of 1,000 and 2,500 meters, causing significant shear turbulence and downdrafts on the Toggenburg side of the ridge. A glider instructor in the vicinity had reported such intense turbulence that he was forced to abort his flight. The official report concludes with high probability that the pilot encountered a sudden loss of altitude due to this lee-side turbulence while flying at insufficient height above ground, resulting in a collision with trees and the terrain. The pilot sustained fatal injuries upon impact, and the aircraft was completely destroyed.