The pilot of the Gippsland Aeronautics GA-200C aircraft had been tasked to apply superphosphate fertiliser to a sloping paddock located close to steeply rising terrain. He reported that prior to commencing spreading operations he intended to conduct an aerial inspection of the area. The pilot had flown in the area before and was familiar with the general terrain.
The pilot reported that just before reaching the treatment area, his aircraft encountered sinking air. Although it appeared that adequate terrain clearance existed to fly the aircraft straight ahead and under powerlines spanning a valley between two hilltop poles, the pilot became concerned about the possibility of an unseen power line between a nearby group of buildings and the nearest hilltop pole. Accordingly, he applied full power and turned the aircraft toward higher terrain. To improve the climb performance of the aircraft, the pilot dumped the contents of the hopper, however he was unable to manoeuvre the aircraft to avoid colliding with the terrain.
A witness reported that he saw the aircraft fly out of a gully towards steeply rising terrain, and recalled that the engine had sounded normal up to the point of impact. The aircraft struck the ground in a wings level attitude, approximately 6 m below the hill-crest and stopped in a distance of less than 10 m.
While running to the aircraft, the witness noticed that a fire had broken out in the wreckage and was slowly spreading through the centre fuselage area. The witness assisted the pilot to move clear of the wreckage.
The pilot sustained burns to his face, both arms, and one hand. He also suffered a fractured skull, a depressed fracture to a cheekbone, spinal injuries and a broken ankle. At the time of the accident he was wearing a helmet, a shirt with cut-off sleeves and denim jeans. Impact forces and post-impact fire destroyed the aircraft.
It was reported that the fuel tanks located in each wing remained intact and contained a significant quantity of fuel, which was not burnt in the post-impact fire. The aircraft's battery was equipped with a 50 amp circuit breaker that had tripped during the accident, thereby removing power from the electrical system. A possible ignition source for the fire was a low-voltage electric livestock fence that was in contact with the wreckage. The fire was fed by fuel leaking from the fuselage mounted fuel collector tank.
The tethering cable for the pilot's upper body restraint was reported to have failed in a mode consistent with a load that had exceeded the design requirements of the harness restraint system. The front and rear supports for the pilot's seat had folded together and distorted the seat pan. The design of the seat and harness system had been tested and demonstrated to be compliant with the 25 G static test requirement.
The pilot subsequently reported that there was not a powerline between the buildings and the nearest hilltop pole as he had anticipated.
The Australian Transport Safety Bureau did not conduct an on-site investigation.