Circumstances:
The pilot had commenced operations with full fuel tanks and was expecting a safe endurance of four hours. After three and a half hours the pilot was flying the aircraft in a right hand turn at 500 feet above ground level when the engine lost power, regained it momentarily and then stopped completely. The pilot rolled the wings level and commenced a forced landing approach. The aircraft touched down on a rocky ridge and collided with a number of trees. Twelve litres of fuel were drained from the right hand wing tank. The left hand wing tank was empty. The aircraft's capacity is 96 litres of which six litres are unusable. At normal fuel usage rates, a safe endurance of 240 minutes can be expected. As the pilot was operating at medium power settings, with flap selected much of the time and the mixture selected to rich, the endurance achieved was probably correct. The most probable explanation for the engine malfunction is that the fuel feed lines were unported from the limited amount of fuel remaining in the right wing during the right hand turn. There was insufficient time for the engine to restart, once the wings were levelled, before the pilot had to land the aircraft.
