On the day of the accident the pilot commenced operations in VH-WLP at about 0630 hours and completed two flights from Mareeba to Kowanyama and return. He then refuelled the aircraft, probably to capacity, adding 184 litres of fuel. The aircraft departed from Mareeba bound for Dunbar at 1430 hours. No passengers or freight were carried and it was intended to uplift five passengers at Dunbar for return to Mareeba. Weather conditions over the route were fine. At 1513 hours the pilot established high frequency radio communications with Weipa Flight Service Unit and reported that his position at 1510 hours was abeam Gamboola, altitude below 5000 feet and estimated arrival time at Dunbar was 1539 hours. Radio communications in the area were adversely affected by ionospheric conditions. At 1520 hours the pilot advised 'returning to Gamboola, estimating Gamboola three zero, have a suspected broken exhaust pipe'. Following a request from Weipa he advised that 'operations normal this time' and 'suspect that I have a broken exhaust pipe by vibration and engine no other indications.' The next communication from the pilot was at 1525 hours when he broadcast 'mayday mayday mayday, whisky lima papa, five miles closing down engine failure partial engine failure.' At 1526 hours the last transmission received from the aircraft was 'whisky lima papa I'm ah all but there to Gamboola five miles short I'm going to have to put down.'