The investigation by the Australian Transport Safety Bureau (ATSB) found that the pilot most likely fell victim to spatial disorientation and lost control of the aircraft.

The aircraft departed from the Norra-Aus Fly-In airshow in Monto a few minutes after 11:00 on a direct track towards Caboolture carrying the pilot and five non-paying passengers.

At 13:15, the aircraft contacted air traffic control, reporting an approximate position 69 km north of Caboolture and requesting assistance with navigation.

A friend of one of the passengers aboard Riama received a phone call from the aircraft, reporting that they were lost in cloud and unable to maintain altitude at around 13:20.

[1] A major search and rescue operation was coordinated by the Australian Maritime Safety Authority (AMSA), involving as many as 15 helicopters as well as a specialized fixed wing aircraft flown in from Melbourne.

The wreckage was discovered just below a ridge line near Lake Borumba, 36 km south west of Gympie on 3 October with none of the occupants having survived the crash.

[5] It was reported that on the weekend prior to the accident, Porter had raised some $15,000 for a Bundaberg based rescue helicopter service by offering joy-flights in Riama.