The pilot had recently finished modifying his Benson style Rotorcraft and he was attempting to have it ready to participate in the annual Sports Aircraft Association of Australia fly-in at Serpentine which was planned for the weekend following the accident. The pilot had not flown since he commenced work on the modifications over twelve months prior to the accident. The Technical Committee from the Rotorcraft Club of WA Inc. inspected the aircraft and its modifications on the day before the accident and they required some changes to be made before the aircraft was flown. Some of the committee members also advised the pilot that he should have an experienced, current pilot with him when he test flew the aircraft. A friend, who was not a Rotorcraft pilot, accompanied the pilot to the Club's flying area on the afternoon of the accident and helped prepare the aircraft for flight. The aircraft became airborne after spending some time taxying around on the ground. The pilot carried out a number of turns. In one turn, the aircraft was also seen to climb and descend, before entering what appeared to be a controlled, steep descent. The aircraft did not completely recover from the descent before it collided with the ground and the pilot was killed. The accident occurred after sunset and just prior to official last light on the dry bed of a salt lake. An inspection of the wreckage did not disclose any faults with the aircraft that may have contributed to the accident. The engine was delivering power at the time of impact.