The pilot and an assistant had rigged a launching device which
utilized a bungee assembly of motor tyre tubes, and a vehicle and
cable to launch a glider over the slope of Big Talbingo Mountain.
It was intended that when the glider was released, sustained
acceleration was to be obtained by the vehicle and cable moving
away from the glider. The weather conditions were favourable with
the glider facing into a wind of 10-15 knots. The assistant
positioned the vehicle such that the slack in the system was taken
up before he spoke to the pilot who was now in the cockpit and who
briefed him again on the required procedure. The vehicle was driven
away, stretching the bungee assembly, but at a speed too slow to
sustain acceleration of the glider after automatic release. The
pilot was aware of the situation, but was committed to the launch
and when further movement of the vehicle automatically released the
cable retaining the glider, the launch commenced and the glider
moved forward without continuing to accelerate and rolled over the
edge of the clearing. The left wing dropped and the aircraft
continued to sink until it struck the rocky cliff face. The
launching system, modified from one used previously by the pilot,
was untried and the procedures to be used had not been
practised.
