The pilot of a Cessna 206, with one passenger, was tracking for Ceduna via Naracoorte and Kangaroo Island, SA.
At 1020 CSuT, the pilot advised air traffic control that the aircraft engine had failed and he would have to ditch the aircraft in the ocean. The controller asked the pilot to switch on the transponder and press the `ident' button. He subsequently identified the aircraft at about 33 NM south of Victor Harbor, SA at an altitude of 7,500 feet. The controller estimated that the aircraft was descending at about 1,000 feet per minute. Radar contact ceased at 1027 as the aircraft was descending through 1,400 feet.
After the first transmission from the pilot, the controller asked the crew of a Royal Australian Air Force (RAAF) aircraft to divert to the area to assist with search and rescue. The RAAF aircraft located the passenger in the ocean and remained in the area until a helicopter arrived and winched him aboard. The pilot was not found.
The Cessna 206 was not carrying a life raft, nor was it required to.
The passenger later said that the aircraft engine was operating normally until it suddenly made a loud grinding sound and the propeller stopped rotating. The cockpit then filled with smoke. The pilot tried unsuccessfully to restart the engine. The passenger fitted life jackets to himself and the pilot. On contact with the water the aircraft overturned and rapidly filled with water. The passenger was unable to sight the pilot so he made his way to the surface and inflated his life jacket.
Examination of the aircraft was not possible as it sank without trace.
The passenger said that, just before the engine failed, the aircraft fuel tank gauges indicated about 3/4 in the right tank and 1/4 in the left tank. Examination of fuel records indicated the aircraft should have had sufficient fuel at the time of the accident. Records also indicated the aircraft had not been refuelled with contaminated fuel in late 1999 and consequently was not subject to an airworthiness directive that required the complete cleaning and flushing of the fuel system.
Examination of the aircraft maintenance records indicated that on 10 April 1995, about 339 flight hours before the accident, the crankcase, sump, camshaft and a connecting rod assembly were replaced due to a connecting rod failure, with components assessed as serviceable by an engineer.
At about 132 flight hours before the accident, on 03 September 1998, a replacement engine cylinder assembly was fitted.
On 23 September 1999, a new propeller and two serviceable engine cylinder assemblies were fitted following a propeller strike. The aircraft had then flown for about 56 hours before the accident.
Four days prior to the accident, on 04 March 2000, the aircraft had undergone a routine 100 hourly maintenance check. At the time of the accident, the aircraft would have completed about six hours flight time since the maintenance check.
The reason for the reported engine failure could not be determined.