Accident Overview
At 1946 Eastern Standard Time on 31 July 2007, a Rockwell International Aero Commander 500S, registered VH-YJB, departed Essendon Airport, Victoria on a business flight to Shepparton. The flight was conducted at night under instrument flight rules (IFR) with a pilot and one passenger on board. At 1958, while cruising at 7,000 ft above mean sea level in Class C controlled airspace, radar and radio contact with the aircraft was lost simultaneously by air traffic control when the aircraft was approximately 25 NM north-north-east of Essendon. The air traffic controller declared a distress phase after multiple unsuccessful attempts to contact the pilot. At 2003, the Operations Director at Melbourne Centre declared the aircraft probably lost and advised AusSAR.
Search and Wreckage Location
A search was initiated using a helicopter, an aeroplane, and ground parties. No emergency locator transmitter signal was reported. At 2147, aircraft wreckage was located by a searching aircraft in timbered ranges near Clonbinane, approximately 50 km north of Melbourne. At about 2200, a ground search party confirmed the wreckage was that of VH-YJB and that there were no survivors.
Flight Sequence
Earlier that evening, the pilot had landed at Essendon at 1915 from a previous flight in another aircraft. He was then tasked to fly the company owner, who was also a licensed aircraft maintenance engineer, to Shepparton to replace an unserviceable starter motor. The pilot transferred to VH-YJB, which had been prepared for flight by another company pilot. At 1938, while taxiing for takeoff, the pilot advised the aerodrome controller of his intention to conduct the IFR flight and requested a favour to submit a flight plan with an urgent departure to Shepparton and return. The aerodrome controller sought assistance from a controller in the Melbourne air traffic control centre.
No eyewitnesses to the accident were identified. Residents in the vicinity reported difficulty hearing due to wind and foliage noise. One resident reported hearing a brief, loud engine noise described as constant, not spluttering or misfiring, lasting only a few seconds. Another resident thought it was a noisy vehicle. Moments after the engine noise ceased, some residents near the accident site reported hearing and feeling an impact.
Wreckage Examination
The aircraft was seriously damaged by excessive in-flight aerodynamic forces and impact with terrain. Vegetation near the main wreckage was slightly damaged as the aircraft descended nearly vertically through trees. A detailed examination by ATSB investigation staff found that all principal structural failures occurred under gross overstress conditions—stresses significantly exceeding the physical strength of the structures. No evidence of pre-existing cracking, damage, or material degradation was found that could have reduced strength. Original manufacture, maintenance, or repair processes were not contributory.
The break-up sequence involved a large negative (downward) loading on the wing structure, resulting in bending failure of both wings outboard of the engine nacelles. After separation, both wings moved aft and impacted the leading edges of both horizontal tailplanes, causing the empennage to separate from the fuselage. The left engine nacelle fairing likely lost due to contact with a wing leading edge. All control surfaces failed under overstress, with no evidence of flutter.
Findings
The following verified findings were made: all principal failures in wings, tailplanes, and empennage resulted from gross overstress; multiple in-flight structural failures occurred; the structural failure sequence was initiated by symmetric downward bending failure of both wing sections; empennage separation was initiated by impact from the separated outboard wings; no material or manufacturing abnormalities were implicated; no service-related degradation (corrosion, fatigue, environmental cracking) affected the aircraft structure in failure areas.