Astir CS collision with tree during ridge flight near Olten, Switzerland
On July 10, 1982, a Grob Astir CS was involved in an incident near Born bei Olten, Switzerland, during a private training flight. The glider collided with a tree while flying close to the ridge, leading to damage on one wing. This resulted in a loss of control and a subsequent crash into a forested area. The pilot sustained serious injuries, including facial soft tissue damage, a complex leg fracture, and a concussion. The glider was destroyed in the incident.
- Winch launch ridge flight: The pilot winch-launched the Astir CS from Olten and proceeded to fly ridge-soaring along the Born crest in weakening lift conditions.
- Weakening ridge lift: Around 1900 local time the ridge lift at Born was abating, making it difficult for gliders to maintain or exceed crest height according to other pilots.
- Low height near ridge: Witnesses observed the accident glider flying relatively low along the Born slope, with limited clearance above the trees.
- Collision with tree: While ridge-soaring close to the slope, the glider likely struck a tree, as suggested by a freshly broken treetop found above the accident site and subsequent wing damage.
- Wing damage loss of control: After the impact, witnesses saw one wingtip hanging down, indicating structural damage that led to loss of roll control and the onset of a spinning or rotating descent.
- Crash - serious injury: The uncontrollable glider descended in a turning motion into the forest near Borngrube, was destroyed, and the pilot sustained serious injuries including facial soft tissue damage, a complex leg fracture, and a concussion.