While enroute to the treatment area the pilot noted a loss of engine power. After the load of superphosphate was dumped, he realised he would be unable to return to the DEPARTURE strip and selected a track as the most suitable landing area. During the landing roll the aircraft ran over a hump which caused it to slew off the track into the surrounding bush. Engine examination revealed that the fuel injector system was out of adjustment, producing a lean mixture at high power settings. The resulting high combustion temperatures produced abnormal engine wear and led to spark plug failure.
