What happened
On 17 June 2018, a DG Flugzeugbau DG-808 S glider, registered F-CTZT, was performing a local flight at the Chartres Métropole aerodrome. The aircraft was positioned at the threshold of the unpaved runway 09, prepared for a winch launch. As the launch commenced, the wing assistant held the left wing for the first few meters of the takeoff run before releasing it.
During the initial acceleration, the pilot experienced a sudden drop in the right wing accompanied by a rightward yaw. The pilot attempted to correct the flight path using left rudder and control stick inputs; however, the right wing made contact with the ground. Upon noticing that the winch cable was angled at approximately 30 degrees relative to the fuselage axis, the pilot activated the release handle. This action caused the glider to rotate around the right wing, lifting the fuselage into a near-vertical, nose-down position before it fell back onto the runway, resulting in severe damage to the aircraft.
The investigation
The investigation relied on pilot statements and video footage captured by a bystander near the runway. The video analysis revealed that while the wings were relatively level at the start of the launch, the left wing tip was moving upward at the moment the assistant released it. The investigators established that approximately five seconds elapsed between the start of the takeoff run and the cable release.
Findings
- The wing assistant's failure to maintain wing levelness may have contributed to the loss of directional control.
- The pilot's delayed reaction time in activating the release handle after the wing hit the ground led to the cartwheel motion.
- The aircraft was operating in calm to moderate winds (approximately 5 knots) from the left.