On the evening of October 21, 1978, 20-year-old Frederick Valentich took off from Moorabbin in a Cessna 182 to fly 125 nautical miles across Bass Strait to King Island. Over the water he radioed Melbourne air traffic control that a large aircraft with four bright lights was about 1,000 feet above him and moving very fast.
For about six minutes Valentich described the object orbiting him, with a green light and a metallic shine. Then he reported that his engine was running rough. His last words were: "It's not an aircraft." The controller heard 17 seconds of metallic, scraping noise and then nothing.
A large air and sea search found no trace of Valentich or the plane. The Department of Transport thought he may have become disoriented and seen his own lights reflected in the water, or the lights of King Island, while flying upside down. Others have suggested he staged his disappearance. The case is still open.