On his previous two refuelling stops the pilot filled both the main and auxiliary tanks. At his final refuelling stop the pilot filled the main tank only as he expected to be airborne for no more than a further 30 minutes. The pilot normally used elapsed time in conjunction with the fuel gauge indications to determine his safe endurance. He did not note the time following his last refuel. The final flight lasted considerably longer than expected and the pilot forgot to monitor the fuel usage. Shortly before the accident the pilot noted that the fuel gauge was reading between empty and one quarter full. At that point the pilot had less than his minimum fuel reserve on board the aircraft. He was aware that the low fuel warning system was unserviceable and he could have established radio contact with his home base to arrange for fuel. Suitable areas existed in the vicinty where a precautionary landing could have been carried out. He decided, however, to continue flying towards a stock yard where fuel was located. Approximately 5 minutes later the engine stopped, from fuel exhaustion, with the helicopter at a low height above the ground.