What happened
On July 1, 2006, at approximately 12:00 local time, a student pilot prepared a Grob Astir-CS glider for a training flight at Hilden-Kesselweier. Following a pre-flight inspection by an instructor, the student pilot initiated a winch launch. Shortly after takeoff, the glider began drifting to the left. During the ascent, the winch operator observed unusual flight movements and subsequently terminated the winch tow, causing the tow rope to detach from the aircraft.
At an altitude of approximately 80 meters, the glider began performing left-hand circles, with the bank angle increasing significantly. The aircraft completed a full circle before impacting a field adjacent to runway 06 at a bank angle exceeding 45 degrees. The impact, which first struck the left wing and then the forward fuselage, resulted in the destruction of the aircraft and left the student pilot with serious injuries.
The investigation
The BFU examined the wreckage and the flight sequence. The investigation found that the impact caused the fuselage and wing components to fracture multiple times, and the left wing was severed from the aircraft. Regarding the flight controls, the investigation determined that all control connections were severed due to the force of the impact, with the exception of one specific connection. The linkage for the left aileron showed no signs of pre-impact damage or mechanical failure; the connection was found in an open position, but the locking mechanism was properly secured with an additional safety device. Post-accident functional testing of the control systems showed no identifiable restrictions.
Findings
- The winch launch was terminated by the operator due to unusual flight movements observed in the glider.
- The aircraft entered a descending spiral with an increasing bank angle following the release of the tow rope.