What happened
On August 6, 2014, at 17:35 local time, a Schleicher ASK18 glider, registration F-CLAN, was performing a winch launch from the unpaved runway 32 at the Chambéry - Challes-les-Eaux aerodrome. Shortly after takeoff, the aircraft entered an excessive pitch-up attitude. At an altitude of approximately 30 meters, the glider banked to the left and entered a stall. The pilot immediately released the winch cable and attempted to reduce the pitch. However, the left wing and the nose of the aircraft struck the ground, resulting in the destruction of the glider and one injury to the pilot.
The investigation
The investigation examined the wreckage and the pilot's experience. Examination of the debris confirmed the aircraft impacted the ground in a left turn with a nose-down attitude; no mechanical failures were identified. The status of the elevator trim setting could not be definitively determined from the wreckage.
The pilot had recently obtained his glider license in July 2014 and had accumulated 3eler 33 flight hours, with only 29 hours flown solo. This was his first flight since receiving his license. The pilot noted that during the initial acceleration of the winch launch, the force pressed him against the seat back, causing him to inadvertently pull back on the control stick. He also noted a potential error in the elevator trim setting, as he was unsure if he had verified its position during the pre-flight checklist.
An instructor present at the scene observed that while the initial acceleration felt normal, the climb gradient after rotation was excessive. The instructor also noted that the winch position typically creates a slight rightward pull at the start of the launch, which the pilot attempted to counter with left rudder.
Findings
- The primary cause of the accident was the involuntary rearward movement of the control stick by the pilot during the high-acceleration phase of the winch launch, which induced an excessive pitch-up attitude.
- The pilot's failure to verify the elevator trim position during the pre-flight checklist may have contributed to the aircraft departing from controlled flight with an incorrect trim setting.
- The pilot's rapid release of the winch cable prevented a more severe outcome during the stall.