Collision with terrain involving a Let National L13, VH-GGI, Formby Road South, Western Australia, on 17 July 1996

The aim of the flight was to check the front seat pilot's capabilities in assessing and flying slope-lift generated by mountain slopes. The area near the mountain became unsuitable for continued operations due to mist and the presence of other aircraft. As a result, the crew decide to return to their base. The instructor reported that as the glider passed through a saddle, with sufficient height and speed to reach the airfield, it was caught in a series of downdrafts. A significant amount of altitude was lost in the turbulence and the glider continued to lose altitude rapidly once it reached clear air. The air brakes were found in the fully deployed position. They had not been selected by either pilot. The glider was 300 ft above ground level and over trees when the air brakes were selected in. The glider had insufficient performance available to reach the airfield.

The pilots decided to complete an outlanding on a road. The space between the trees on either side of the road was less than the glider's wingspan and the right wing and canopy collided with trees during the landing. The glider came to a stop in the trees at the side of the road.

It is probable the airbrakes were deployed by the loadings encountered during the turbulence.