The ATSB investigation into the fatal Aero Commander accident on 19 February 2004, 58 km NNW of Hobart is focusing on the reason for an overload failure of the wings in flight.
The ATSB interim factual report finds that the wreckage pattern was consistent with the aircraft having sustained an in-flight structural failure of both wings and the tailplane. The outboard left and right wing sections had separated from the aircraft at similar positions along the respective wings and in a downward direction. However, there was no evidence of corrosion, fatigue cracking or airframe modifications that could have degraded the strength of the wing or tailplane structures.
The aircraft was being operated on a visual flight rules ferry flight to Devonport. The pilot, the sole occupant, reported an intention to climb the aircraft to a cruising altitude of 8,500 ft. The aircraft was not required to be fitted with a flight data recorder or cockpit voice recorder and there was no other recorded information available.
The main parts of the aircraft, consisting of the forward and aft fuselage, inboard wing sections and flaps were found upside down in undulating terrain at 560 metres above mean sea level. Both engines and propellers were with the main wreckage. The remainder of the aircraft structure was scattered to the east-north-east of the main wreckage, with some less heavy items up to 1,300 m away.
The investigation is continuing and is examining aspects of the aircraft's structures, automatic flight control system, flight operations, air traffic control, meteorological conditions and human performance.