The pilot had engaged in gliding activities for more than thirty years. These activities were interrupted in December 1987 when he underwent coronary by-pass surgery. On receipt of a medical clearance from his coronary specialist, the pilot resumed flying gliders in February 1989. He had since accumulated 31 flights of which 18 were solo. On the day of the accident, the pilot arrived at the airstrip at about 0930 hours and during the day assisted with glider launch and recovery operations. Late in the afternoon the pilot was authorised by the duty officer for a solo flight. After a winch launch in a northerly direction in light wind conditions, the glider was observed to perform several steep turns before positioning for a right hand downwind leg for a landing in a northerly direction. The pilot reported his position by radio on the downwind leg in accordance with the gliding club's standard procedures. The flight was witnessed by numerous club members who were generally located at the southern end of the airstrip. They reported the approach appeared normal until the glider was established on base leg. The turn onto the final approach was delayed such that the glider lined up on the western side of the strip which is reserved for winch launches. Soon after, when the glider was at an altitude of about 150 feet above ground level, it commenced a turn to the left. The glider levelled out on a south-westerly heading and then entered a climb, from which it apparently stalled, and dived from view behind trees. The wreckage was found in timbered country about one kilometre from the southern end of the gliding strip. The wreckage distribution suggested the glider had rolled inverted and dived near vertically into the ground. A technical examination revealed no evidence of any pre-existing fault or defect. The manoeuvres following the turn onto final approach were consistent with the pilot being incapacitated. The autopsy revealed the pilot had suffered a heart attack.