What happened
On July 1, 1961, a Piper J3C, registration HB-OXC, departed from the Bad Ragaz airfield for a series of training flights. The aircraft was operated by a pilot with significant experience in this specific model, though he was currently behind on the flight hours required for license renewal. On this particular flight, the pilot was accompanied by a minor passenger.
After flying over the Flumserberge region, the aircraft proceeded toward Walenstadt at an altitude of approximately 400 meters. The flight path then took the aircraft over the center of Lake Walen, heading west. During the flight, the aircraft began to lose altitude. As the plane approached the steep northern shore of the lake, it entered a left-hand turn. At approximately 11:15, the aircraft struck the water with its left wingtip, propeller, and landing gear. The impact caused the propeller to shatter and the aircraft to sink rapidly into the lake, where it remained at a depth of over 100 meters. Both the pilot and the passenger, two fatalities, perished in the accident.
The investigation
Investigators examined the wreckage recovered from the lakebed in late September 1961. The examination of the HB-OXC revealed that the engine was running at the time of impact, the ignition was on, and the fuel valve was open. Notably, the trim was set in a heavily tail-heavy position.
While the investigation could not definitively determine if the pilot had handed control to the passenger via the dual controls—as had occurred on a previous flight—the physical evidence and the pilot's known flying habits provided a clear picture of the flight's final moments. The investigation also noted that the pilot had a documented tendency to fly at minimum speeds, even during critical phases of flight.
Findings
- The pilot was flying below the minimum required altitude prescribed by aviation regulations.
- The aircraft likely entered a stall due to the pilot flying below the minimum airspeed during a turn.
- The tail-heavy trim setting may have contributed to the loss of control.
- The pilot failed to maintain sufficient altitude margin, which would have provided the necessary buffer to recover from a developing emergency.