Sequence of Events
The glider was aligned at the start of the west-northwest takeoff axis on the restricted-use aerodrome of La Tour du Pin Cessieu (38) for a towed takeoff. The tow rope was attached to the glider's front hook. The pilot signaled readiness to the ground crew and applied operational procedures specific to this glider type: he kept his left hand on the airbrake control to keep them partially extended and maintained a slight back pressure on the control stick. These actions are recommended for this type at the start of the roll to keep the tail wheel on the ground and stabilize the glider in crosswind.
The ground crew raised the right wing to signal the tow pilot to start. During the first tens of meters, the pilot kept the wings level and the glider aligned. He then noticed an increase in yaw to the right. He applied left inputs on the stick and rudder but observed no effect. The tow rope formed an angle greater than 20° relative to the takeoff axis and the tug's trajectory.
The pilot released the airbrake control to pull the release handle. The airbrakes retracted, and the glider lifted about one meter. Due to the control deflections and lateral pull from the rope, the glider quickly banked left and turned left. The tow rope detached during this motion. The glider fell back at 90° across the initial path, and the tail boom broke upon impact of the main wheel with the ground.
Additional Information
The pilot had 82 hours of glider flight time, including 31 hours on type, and six hours in the previous 30 days. The estimated wind was northwest at 5 to 10 knots.
According to the pilot, the deviation may have been caused by the tug's propeller wash or a wind gust. Less than two seconds elapsed between the realization of an unrecoverable deviation and the release.
Conclusion
During this accident, the sudden change in glider behavior on two axes after airbrake retraction and the proximity to the ground made recovery difficult. The pilot's prior roll input to correct the trajectory may have complicated the situation.