Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
The aeroplane pilot took off from runway 01 at Bagnères-de-Luchon aerodrome to tow the glider.
Shortly after take-off, at a height estimated by the witnesses to be about 50 m, the tow cable slackened before suddenly becoming taut again. The glider entered a nose-up attitude and rose to become higher than the aeroplane, which slowed the aeroplane and caused it to take a nose-down attitude.
The glider pilot and the aeroplane pilot released the tow cable simultaneously.
The glider pilot made a tight manoeuvre to the right and landed on the runway on the reciprocal QFU. At the same time, the aeroplane collided with the runway.
The take-off occurred with an airspeed higher than usual for a glider such as the Ka 6E (around
130 km/h). This may have induced a more dynamic and unstable performance of the glider flying in turbulent air with gusts of wind. The glider thus became more difficult to control. The glider pilot had intended to inform the aeroplane pilot of this high speed over the radio.
During the initial climb, in order to avoid rising higher than the tug plane, the glider pilot applied a nose-down action with the stick, which increased the glider’s speed. The aeroplane pilot probably reduced the engine power to keep the engine in its operating range. The aeroplane’s speed decreased. This decrease in speed combined with the increase in the glider’s speed may have caused the tow cable to slacken.
When the cable became taut again, the glider’s pitch attitude suddenly increased due to the position of the tow hook near the centre of gravity, which destabilised the pilot in her seat. It is possible that, in this phase, she unintentionally operated the stick rearward, amplifying the attitude adopted.
The glider rose around 10 metres higher than the tug plane, slowing it and causing it to take a nose-down attitude. During this sequence, the glider pilot and the aeroplane pilot released the tow cable. The aeroplane pilot initiated a pull-up manoeuvre but was unable to avoid collision with the ground. The glider pilot made a tight manoeuvre to the right and landed on the reciprocal QFU.