Cessna 172-N, VH-PJH, Proserpine QLD, 1 October 1988

The pilot reported that as the aircraft climbed through about 300 feet after takeoff, the engine RPM suddenly dropped by 350-400. This was accompanied by rough running. The pilot decided to land in a gravel pit just beyond the airfield boundary. The aircraft was stopped after a ground run of 150 metres but received substantial damage due to the rough surface. The engine problem was probably caused by sticking valve(s). This accident was not the subject of an on-site investigation.