The pilot of the Lancair had built the aircraft as an owner-builder. He and his passenger had intended to fly from Perth, Western Australia to an airshow at Mangalore, Victoria. On the day prior to the accident, the aircraft arrived early in the afternoon at Aldinga, South Australia, where it was refuelled in preparation for the next leg of the flight. The pilot and passenger then stayed overnight with a friend. The following morning, the aircraft departed for Murray Bridge, South Australia in order to meet up with another aircraft for the remaining flight to Mangalore.
When the aircraft was 3 km to the north-east of Aldinga aerodrome, witnesses heard the engine surge and lose power. The aircraft was then seen to enter a spin and crash into a dry creek bed. Both occupants were fatally injured. The accident was not considered to be survivable.
Traces of aviation fuel were found on the ground at the accident site under the wing fuel tanks. There was no evidence that a significant quantity of fuel had been released during the impact. There had been no post-impact fire.
The investigation established that the aircraft had been refuelled the previous day at Aldinga to a capacity of approximately 80L. It was operating within weight and balance limitations, close to its maximum weight, and close to the aft limit of its centre of gravity. There was no evidence to suggest that the aircraft was not airworthy prior to the accident, nor was there any indication that either the pilot or the passenger had been incapacitated immediately before the accident.
The aircraft utilised three fuel tanks: one was located in each wing below the level of the engine, while the third fuel tank was located in the fuselage, above the level of the engine. The engine could be fed with fuel directly from any one of these.
It was the pilot's normal policy to use fuel from the fuselage tank when priming the carburettor prior to starting the engine, and then to select a wing fuel tank once the engine had been started. During the flight from Western Australia, only the wing fuel tanks had been filled at all refuelling ports except for Ceduna, where it was not possible to ascertain how the aircraft had been refuelled. Investigation revealed that at the time of the accident, the low-fuel warning light for the fuselage tank was illuminated, indicating that only a small quantity of fuel remained in that tank.
The investigation found that aviation fuel had been spilled on the ground, chemically burning the grass, at the aircraft's overnight parking location at Aldinga aerodrome. The shape of the burnt grass area was consistent with fuel having been spilled over the sides of a 20 L fuel drum. Police reported that fuel had been stolen on other occasions from aircraft at Aldinga aerodrome. A road near the aerodrome was regularly used for car racing, and it is possible that fuel was siphoned overnight from the aircraft's fuel tanks.
Damage to the aircraft systems precluded a determination of the fuel tank that was selected at the time of the accident. A lack of both fire damage and evidence of fuel spillage at the accident site indicated that there was only a small quantity of fuel in the aircraft at the time of the accident, despite the aircraft having been refuelled the previous day. It was not possible to ascertain if the engine lost power due to fuel exhaustion from a wing fuel tank, or if the fuselage tank had been selected prior to take-off and that that tank had become exhausted.
The reason for the aircraft entering a spin after the engine lost power could not be determined.