The pilot had refuelled the aircraft to full tanks the previous day and then flown a total of 1.6 hours. On the day of the accident he completed a flight from Darwin of 1.1 hours duration. Four minutes after leaving Cooinda, at an altitude of 1000 ft, the engine failed and the pilot's attempts to restart the engine were unsuccessful. A forced landing was attempted into a short clearing but the aircraft over-ran the clearing and collided with trees. Investigation established that the pilot used the left tank but mistakenly recorded flying on the right tank for 1.6 hours the previous day and used the left tank again for 1.1 hours on the trip to Cooinda. On-site investigation established that the intact left tank was empty and right tank, although leaking, contained a significant amount of fuel. Other evidence established that the fuel gauges were not serviceable and the pilot did not select the electric boost pump to ON after changing tanks in his attempt to restart the engine. A series of engine run tests carried out after the accident showed no fault with the engine, and that the engine would recover after fuel exhaustion on one tank if the electric boost pump was selected ON after changing tanks.