Valentich disappearance
A pilot with a Class Four instrument rating and 150 hours of flight experience, Valentich filed a flight plan from Moorabbin Airport, Melbourne, to King Island in Bass Strait on 21 October 1978. Visibility was good and winds were light. He was flying a Cessna 182-L, with a cruising speed of around 256 km/h (160 mph). He departed Moorabbin at 18:19 local time, contacted the Melbourne Flight Service Unit to inform them of his presence, and reported reaching Cape Otway at 19:00.
At 19:06, Valentich asked Melbourne Flight Service Officer Steve Robey for information on other aircraft at his altitude (below 5000 ft, 1524 m) and was told there was no known traffic at that level. Valentich said he could see a large unknown aircraft which appeared to be illuminated by four bright landing lights. He was unable to confirm its type, but said it had passed about 1,000 feet (300 m) overhead and was moving at high speed. Valentich then reported that the aircraft was approaching him from the east and said the other pilot might be purposely toying with him.
At 19:09 Robey asked Valentich to confirm his altitude and that he was unable to identify the aircraft. Valentich confirmed his altitude and began to describe the aircraft, saying that it was "long", but that it was traveling too fast for him to describe it in more detail. Valentich stopped transmitting for about 30 seconds, during which time Robey asked for an estimate of the aircraft's size. Valentich replied that the aircraft was "orbiting" above him and that it had a shiny metal surface and a green light on it. This was followed by 28 seconds silence before Valentich reported that the aircraft had vanished. There was a further 25-second break in communications before Valentich reported that it was now approaching from the southwest. Twenty-nine seconds later, at 19:12:09 Valentich reported that he was experiencing engine problems and was going to proceed to King Island. There was brief silence until he said "it is hovering and it's not an aircraft". This was followed by 17 seconds of unidentified noise, described as being "metallic, scraping sounds", then all contact was lost.
http://en.wikipedia.org/wiki/Valentich_Disappearance