The pilot conducted a daily inspection of the helicopter prior to meeting another company pilot to fly two helicopters to a mustering camp. After start he reported by radio to the pilot of the lead aircraft that he was ready to depart. Ground witnesses saw the two helicopters depart in company. The lead pilot proceeded to Hell's Gate and landed but the second aircraft did not arrive. The second helicopter was found one day later about 7 km from Doomadgee and on the extended centre-line of the runway. Examination of the wreckage indicates that the helicopter struck the ground inverted and with a high rate of descent. No pre-existing defects were found in the helicopter. No evidence to indicate that the pilot was other than healthy or suffered from any incapacitation was found during a post-mortem examination. While the factors associated with the cause of this accident were not determined, one possibility is that the pilot suffered a flicker induced seizure. This phenomenon can be caused by the passage of sunlight through the main rotor creating a strobe effect in the cockpit. It may have resulted in control inputs, by the pilot, which could have caused the helicopter to become inverted and crash.