The pilot departed the property strip with the apparent intention of flying to a position near a town some 16 kilometres to the North. Witnesses in the town subsequently observed the aircraft as it arrived in the area. It was evidently performing normally as the pilot completed a level turn and took up a southerly heading. The aircraft then entered a descent, which was described as being similar to a landing approach except that the engine was operating at high power. The aircraft then disappeared from sight behind a hill and the wreckage was subsequently sighted by the pilot of another ultralight aircraft. It was determined that the aircraft had struck the ground in about a 20 degrees nose-down attitude. The pilot had been restrained by a lap-type seat harness and the flexing of his body during the impact had resulted in the stretching and dislocation of his thoracic spine. Specialist medical opinion indicated that the accident would probably have been survivable had the pilot been restrained by a full harness. The area where the accident occurred was not suitable for a normal landing. The investigation did not reveal any defect or malfunction with the aircraft, or any pre-existing medical condition with the pilot that might have accounted for the accident. The precise causes of the occurrence could not be determined.