The aircraft had been refuelled the previous afternoon and hangared overnight. When the pilot and passengers arrived the following morning, the pilot loaded their baggage and freight into the aircraft. The aircraft was pushed out of the hangar and the pilot carried out a pre-flight inspection. After the passengers boarded the aircraft the engine was started and an engine check completed before the aircraft was taxiied to commence take-off from runway 15. About 12 minutes after take-off, the pilot reported that the engine was malfunctioning. It subsequently lost power completely and the pilot was committed to a forced landing. The sea conditions were unfavourable for the aircraft type, with estimated strong winds and about a 1.5 metre swell. The aircraft cartwheeled on touchdown and sank almost immediately. The pilot and two of the passengers were able to free themselves from the sinking aircraft and make their way to the surface. There they supported themselves on the floats which had become detached from the aircraft during the landing. Their subsequent attempts to locate the aircraft and rescue the other passenger were unsuccessful. The three men were later rescued by a police boat. An extensive search of the area, at the time, failed to locate the missing aircraft. About twelve weeks after the accident the engine was located by a trawler and salvaged. Some seven weeks later the airframe was located by another trawler, it was also salvaged. Following the salvage of each part of the aircraft it was washed down and subjected to extensive examination. The immersion of the wreckage in salt water and the growth of marine life on the wreckage inhibited this examination. However, no fault was found that may have contributed to the accident. The investigation did reveal that at the time of take-off the aircraft was approximately 300 kilograms in excess of the maximum allowable all up weight.