On October 21, 1978, 20-year-old Frederick Valentich disappeared over Bass Strait in a Cessna 182L (registration VH-DSJ) while radioing Melbourne Flight Service about a UAP tracking him. At 19:12, his final transmission: “That strange aircraft is hovering on top of me again… it’s not an aircraft.” Followed by 17 seconds of metallic scraping sounds. Then silence. Neither Valentich nor his aircraft were ever found. The official Department of Transport investigation report (1982) concluded: “The reason for the disappearance of the aircraft has not been determined.” Critical context: Valentich had been permitted to view the RAAF’s confidential UFO files at East Sale and Laverton air bases before his final flight. The official file (NAA reference B1497, V116/783/1047) was declared “lost or destroyed” to researchers in 2004 — until researcher Keith Basterfield found it in NAA online archives in 2012. The file reveals: radar plots of the area, a broader radio transcript than publicly released, a Department of Defence water sample analysis from Bass Strait, a report on metallic “scintillations” seen over the area, and — crucially — that aircraft wreckage with partial matching serial numbers was found in Bass Strait five years after the disappearance. Multiple UAP sightings were reported across Victoria, NSW, Tasmania, and South Australia on the same evening. The file also contains a photo taken 20 minutes before Valentich’s disappearance showing a dark object over Bass Strait.