At the conclusion of night spraying operations the pilot departed for Mungindi. Witnesses at the town saw the aircraft overflying at a low height and heading towards the aerodrome, which is about 7 kilometres from the town. Engine noise was then heard to cease and sounds of impact followed. The aircraft had struck the ground 5 kilometres from the aerodrome, and a post-impact fire had engulfed the wreckage. No fault could be found with the aircraft or its systems that could have contributed to the accident. Specialist medical opinion indicated that the pilot had suffered a heart attack before the fire occurred. It was not possible to determine to what extent, if any, the pilot was able to control the aircraft prior to impact.