VH-SPP departed Cloncurry on a low level aero-magnetic survey
flight at the estimated time of 0730 EST with an endurance of about
7 hours. The aircraft was due to return to Cloncurry by 1230 but
failed to arrive. Attempts were made to contact the aircraft
throughout the afternoon before it was declared overdue at about
2030. The burnt-out wreckage of the aircraft was found by search
aircraft the following morning about 9 km north of the survey area
and 30 km south of Cloncurry.
The aircraft had struck the ground in a nose-down, inverted
attitude. It bounced from this position and came to rest upright,
facing the opposite direction. At impact, the left propeller was in
the feathered position and fuel to this engine had been shut off.
The right engine was operating normally at impact, with fuel being
fed from the centre tank.
The investigation revealed that, apart from a 2-hour flight the
previous day, the pilot had no other experience in SPP. It was also
revealed that there were two significant differences between the
fuel system in SPP and that of other Aero Commander models the
pilot had flown. These differences concerned the time taken for the
outboard fuel tanks to empty and the orientation of the cockpit
fuel selector switches.
The analysis concludes that these differences probably led to
mismanagement of the fuel system by the pilot and to failure of the
left engine due to fuel starvation, followed a short time later by
failure of the right engine, also due to fuel starvation. It is
possible that the pilot realised what had happened and was able to
restart the right engine but not before the performance of the
aircraft had deteriorated to such an extent that control of the
aircraft with one engine operating could not be maintained.