B4-PC11AF incident at Etzelstock east slope near Haslen, Switzerland involving stall and tree impact

On June 21, 1986, a Pilatus B4-PC 11AF took off from Schänis Airfield for a local flight. The pilot released the tow cable at 1900 meters and navigated through several mountain areas. While circling at 1600 meters near the east slope of Etzelstock, the glider stalled and collided with trees, causing a 430-degree right rotation. The impact with a rock face and trees resulted in the wings being torn off. The pilot sustained minor injuries, and the aircraft was destroyed.