Accident to the Schempp Hirth - Discus 2A registered F-CFDX on 30/07/2020 at Château-Arnoux Saint-Auban (Alpes-de-Haute-Provence)

Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.

The tug pilot took off from one of the tug strips at Château-Arnoux Saint-Auban aerodrome, facing south. He adopted a climb attitude whilst the ballasted glider was still on the ground. When the glider left the ground, it did not have enough speed and remained in the low tow position in relation to the tug aeroplane. The glider pilot stated this over the frequency, but the tug pilot continued to climb. The tug plane turned right. During the turn, the glider pilot released the cable and landed in a ploughed field located in front of him, avoiding obstacles.
When the cable was hooked to the glider, the tug microlight pilot did not identify in his rear-view mirror that the wings of the glider that he was preparing to tow were horizontal, indicating that it was ballasted. The tug pilot took off without knowing the characteristics of the glider, including its tow speed and the ballasting. This information would have enabled him to adapt the path of the microlight as well as the take-off and climb speeds.
The pilot of the tug microlight started the climb before the glider took off. The glider pilot then made a call over the frequency to draw the tug pilot’s attention to the situation. When the glider left the ground, it found itself in the low tow position with a speed below the recommended towing speed. The glider pilot did not release the cable as he was expecting the tug pilot to stop climbing to accelerate. He made several calls over the frequency to the tug pilot, who continued to climb. The glider remained in the low tow position.
The tug pilot then encountered difficulties holding the microlight’s path due to an unsuitable position of the microlight flaps that made it more sensitive to the pulling of the cable caused by the glider’s position deviations. The tug pilot did not release the cable, thinking that the glider pilot would manage to correct his position. The glider pilot released the cable when it slackened. The glider’s nose then dropped; during this movement, the pilot observed a lack of effectiveness on the controls. The glider lost approximately 30 m in height. Deeming it was not possible to reach the runway, the pilot decided to land in a field ahead of him.