What happened
On August 26, 2017, at approximately 14:27, a glider towing operation took place near the Schänis airfield in the canton of St. Gallen. The operation involved a HK 36 TTC aircraft, registered as HB-2328, acting as the tug, and a Discus-2b glider, registered as **D-9830$.
Shortly after departing from the Schänis airfield (LSZX), the pilot of the towing aircraft experienced a sudden loss of engine power accompanied by intense vibrations. In response to the mechanical failure, the pilot of the HB-2328 performed an emergency landing. During the sequence of events, the glider, D-9830, released from the towline and subsequently landed in the nearby terrain. The incident resulted in minor property damage to the aircraft, and no injuries were reported.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) initiated an investigation into the occurrence to determine the circumstances surrounding the engine failure and the subsequent release of the glider.