Summary
On the day prior to the accident the aircraft was flown to Griffith by the pilot and was left with a
maintenance organization for a 100 hourly Inspection. The pilot has said that, on the following morning, the
licensed aircraft maintenance engineer responsible for the inspection drew his attention to a slight oil leak from
around the blanking plug at the forward end of the crankshaft and attempted to rectify the leak by using a hammer
and punch. This has been denied by the engineer. The aircraft departed Griffith and climbed to a cruising
altitude of 1000 to 1500 feet. After about 30 minutes a fine oil mist appeared on the windscreen and gradually
increased until forward visibility became impaired. The pilot decided to return to Griffith and changed heading
accordingly. Oil slicks were now appearing on the upper engine cowl and on the wings and forward vision became
completely obscured. The pilot selected a large field below the aircraft and prepared to execute a precautionary
landing. He obtained a limited amount of lateral vision by opening the canopy slightly. While the aircraft was
banking, he was able to choose an approach path over pine trees but as soon as the wings were leveled he was
unable to see ahead. He then became aware that the aircraft was on the point of stalling so lowered the nose and
opened the throttle but the engine failed to respond. The left wing tip struck a tree branch and the aircraft landed
heavily on the left main wheel and wing tip. The nosewheel entered rough ground and was torn off and the nose
strut dug progressively into the ground causing the aircraft to nose over to an Inverted position after which It
slid 46 metres. After the aircraft came to rest the pilot, with some difficulty, released himself and dragged his
passenger clear of the wreckage. Subsequent examination of the wreckage revealed that a blanking plug was
missing from the forward end of the crankshaft and this had allowed the inflight oil loss. The engine was
completely exhausted of oil and was approaching the point of seizure. The failure of the engine to respond to
throttle movement during the latter part of the approach was probably the result of complete blockage of the air
intake filter by oil.
