During the climb, in a turn, the glider rose higher than the tug plane. The glider pilot was unable to operate the release control, possibly due to an improperly locked seat adjuster. The tug pilot decided not to release the cable, thinking that the glider pilot would do so after he had notified her of the situation. Due to the failure to quickly release the cable, the tug pilot lost control of the aeroplane and the combination nose-dived. The tow cable was subjected to abnormal tension, causing it to break at the tug-side knot. The tug pilot managed to regain control of the aeroplane. At the same time, the glider collided with the vegetation, then the ground.