The panel proposed that the captain may have asked the supernumerary pilot to occupy the co-pilot seat during the flight to Essendon Airport. The supernumerary pilot was on his third flight with the company and had no prior experience flying the C-47 or DC-3. The panel considered that if the supernumerary pilot had occupied the co-pilot seat, and if the captain had called for fuel cross-feed to be turned ON to deal with a fuel pressure problem in one engine, it was possible the supernumerary pilot's lack of familiarity with the DC-3 cockpit caused him to inadvertently engage the automatic pilot. The panel used a DC-3 aircraft with a cockpit identical to that of VH-AET to carry out four flight tests with the gyroscope caged. When the automatic pilot was engaged the control wheel moved forward so strongly it was torn from the pilot's hands, and regaining control required use of both hands and significant force. Initial tests showed that when the pilot was unprepared, up to 600 ft (183 m) could be lost before he identified the problem and disengaged the automatic pilot. On the fourth test the pilot restricted the height loss to 300 ft (91 m). The panel considered the most likely explanation of the accident was inadvertent engagement of the automatic pilot with the gyroscope caged. The investigation panel's report to the Director-General made recommendations including:  On 24 April 1946 the Minister for Civil Aviation, Arthur Drakeford, appointed Mr Justice Simpson of the Supreme Court of the Australian Capital Territory to conduct an inquiry into the accident. Counsel assisting the inquiry was to be Henry Winneke. Justice Simpson examined the evidence in detail, including the evidence put forward in support of the 3 most likely causes identified by the investigation panel. He eventually found there was insufficient evidence to consider any of the theories proved. Justice Simpson's report of the findings of his inquiry was made public by the Minister on 11 June 1946. Simpson said he was satisfied the accident was not caused by failure of any part of the aircraft's structure, its engines or its controls; or failure to remove any of the flight-control clamps prior to takeoff. John Watkins, chairman of the investigation panel, told the inquiry the evidence supporting the theory that inadvertent engagement of the automatic pilot caused the accident was that its control box was recovered from the wreckage and its gyroscope was still caged. The speed valve unit was also recovered and it indicated the automatic pilot was operating at the time of impact.