What happened
On the afternoon of August 26, 1962, a Rhönlerche II glider, registration HB-666, was conducting a ridge soaring flight near Walenstadt as part of the Churfirsten Gliding Group's operations. The flight, which included a passenger, was intended to utilize the rising air along the local slopes.
As the afternoon progressed, the available updraft began to diminish. To maintain altitude, the pilot flew closer to the steep terrain. While navigating the area near the Gilbiwand, the aircraft struck the cables of the Gela-Schlums material cableway. The impact caused the left wing to detach from the fuselage, leading to a loss of control. The glider plummeted approximately 50 to 70 meters, striking a rocky outcrop. The collision resulted in two fatalities: the pilot died at the scene, and the passenger passed away during transit to a hospital. The aircraft was completely destroyed.
The investigation
The investigation examined the flight path, the weather conditions, and the visibility of obstacles in the area. It was established that the pilot had been briefed earlier that morning regarding the presence of hazards in the Berschis area and had been specifically advised not to fly past the village of Tscherlarch to avoid these obstacles.
Investigators also reviewed the technical state of the Rhönlerche II, finding no evidence of mechanical failure. The weather was reported as clear with light clouds and good visibility, though the updrafts were weakening. The investigation also looked into the operational nature of the flight, noting that while passenger flights were being conducted, the group lacked specific authorization for commercial transport.
Findings
- The primary cause of the accident was that the pilot entered a zone containing significant obstacles while flying at a dangerously close distance to the slope due to diminishing updrafts.
- The pilot failed to detect the cableway wires in time to avoid the collision.
- The aircraft was flying in a manner that placed it too close to the terrain, likely an attempt to find remaining lift near the cliff face.
- The cables themselves were extremely difficult to see against the sky, even under good visibility conditions.
- The pilot had exceeded the previously established safety boundary (the village of Tscherlarch) despite earlier warnings and successful adherence to that boundary in previous flights that day.