In a new post at his UFOs - Scientific Research blog, Keith Basterfield writes:
"The disappearance of Australian pilot Frederick Valentich, on 21 October 1978, over Bass Strait, Australia, has always intrigued global UFO researchers. Valentich, flying a light aircraft, registration VH-DSJ, disappeared on a flight from Moorabbin airport, Melbourne, Victoria, to King Island in Bass Strait. Neither he, nor his aircraft, have been seen since. He reported seeing an unusual object in the sky, during the flight."
Well, now the official files on the affair have been declassified, and you can find the full story right here.