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1978 · Bass Strait, between Cape Otway (Victoria) and King Island (Tasmania), Australia

Valentich: the Cessna that vanished over Bass Strait

On the record
Strength A · 10/10 · 5 independent
Evidence 4/4 · Witnesses 3/3 · Backing 3/3

A pilot's recorded radio reports, an official search file and coastal witnesses back the encounter, and no explanation has been shown.

Plausibility High
Score 12 · 7 factors for, 0 against

A pilot's recorded radio reports, an official search file and coastal witnesses; no explanation shown.

See the factors ↓

Natural cause proposed, not demonstrated
NAA A4703, 1978/1205 (DoT SAR file, mirror) · page 1 of 217 · war.gov file, via the ufotransparency.com mirror
When21 October 1978, about 19:06-19:12 local (0906-0912Z)
WhereBass Strait, between Cape Otway (Victoria) and King Island (Tasmania), Australia
Backing5 independent
Witnesses2 named
Evidenceofficial records, sensor data

In their own words

“it is hovering and it's not an aircraft”
Frederick Valentich, Cessna 182 pilot, radio call to Melbourne Flight Service, 21 October 1978 · source

On the evening of 21 October 1978, Frederick Valentich, a 20-year-old pilot, was flying a Cessna 182L, registration VH-DSJ, from Moorabbin to King Island. Over Bass Strait, he radioed Melbourne Flight Service that a large aircraft with lights was manoeuvring around and above him. He said it was "not an aircraft". He then reported his engine rough-idling and running rough. After 17 seconds of open-microphone noise, contact was lost. An air and sea search over several days found an oil slick but no confirmed wreckage. The Department of Transport (DoT) search-and-rescue file records the UFO report alongside the engine problem. The DoT accident investigation summary report of 27 April 1982 reportedly concluded only: "The reason for the disappearance of the aircraft has not been determined." Explanations range from disorientation, to deliberate disappearance or suicide, to an encounter with an unknown object. None has been demonstrated.

Evidence, in date order (5)

  1. 1978Coastal witnesseswitness
    saw a green light near the aircraft's track FAB CENDOC Envelope 09 – 1978 (IUR Dec 1978; mirror page)
  2. Oct 1978Department of Transportofficial
    search-and-rescue file recording the UFO report and the rough engine NAA A4703, 1978/1205 (DoT SAR file, mirror)
  3. 21 Oct 1978Melbourne Flight Service recordingsensor data
    audio of Valentich's transmissions Mirror audio file pages (Valentich ATC audio and last words)
  4. 21 Oct 1978Melbourne Flight Service controller (Steve Robey)witness
    received the transmissions live David Clarke, "Flight into Oblivion" (1 July 2012)
  5. 27 Apr 1982Department of Transportofficial
    1982 summary report: reason for the disappearance not determined ATSB-hosted summary report PDF (not readable from here)

How plausible · High

A pilot's recorded radio reports, an official search file and coastal witnesses; no explanation shown.

  • ●●
    Access Direct observation or instruments.
  • ●●
    Cost of speaking Named on record.
  • ●●
    No gain sought Nothing to gain.
  • ●●
    Checkable details check out Released official records.
  • ●●
    Physical traces or official reaction Instrument data or physical traces.
  • ●○
    Character record Trained professionals.

Plausibility weighs how well an account fits where secrecy hides the documents by design, so missing records never count against it. Strength measures what is documented. Assessed 2026-10-23.

On the record

  • Item 1: Airways Operations Melbourne advised that a distress phase had been initiated for a Cessna 182 overdue at King Island, on a flight from Moorabbin. "The aircraft had reported a rough running engine prior to communications being lost."Westall High
  • Item 5: "SOC AMML said the aircraft reported seeing things (perhaps a UFO) shortly after departing Cape Otway at 0903Z", and asked for drift calculations around the northern tip of King Island.
  • The vessel *Nancy Heath* searched along the intended track with negative results (items 3-4, 11).
  • Item 13: an Orion aircraft reported an oil slick at about 39°S 144°04'E (OCR partly garbled). Fishing vessels stayed at the slick, which appeared to come from a stationary source. The vessel *Nomad* collected an oil sample (item 17).
  • King Island crayfishermen took part, including Graham Oliver (*Helen D*), Hugh Martin (*Nautilus 1*) and John Henderson (*Balamara*) (names from my earlier reading of the file).
  • Item 16: several reports came in of a fast-moving brilliant white light. Mt Stromlo Observatory advised that the night of the 21st was the peak of a meteor stream, with 10-15 sightings per hour.

Claims

A large aircraft with a green light and a shiny metallic exterior orbited above him: "it is hovering and it's not an aircraft (radio transmissions to Melbourne Flight Service (controller named in the literature as Steve Robey), recorded by the DoT. The DoT radio log is the record. I know the transcript text through David Clarke and the IUR as summarised by the mirror; I did not verify it against the tape or the original DoT transcript)firsthandSourced, unconfirmedFrederick Valentich
The engine was rough-idling and coughing just before the final transmission (DoT record (A4703 item 1 confirms "rough running engine"))firsthandSourced, unconfirmedValentich
An oil slick, and later cowling parts with a serial number in VH-DSJ's range, were foundsecondhandSourced, unconfirmedDavid Clarke (2012), from the DoT file. The oil-slick sample was identified as marine diesel, not aviation fuel, according to the IUR as summarised by the mirro
Witnesses on the coast saw a green light near the aircraft's tracksecondhandSourced, unconfirmedlater ufological literature (the IUR lists Paul Norman and Dr Richard Haines among its field sources, per the mirror summary); not verified here.
Valentich was interested in UFOs, had said he feared them, and his father believed a UFO took him (DoT record item 22 confirms the father's belief)firsthandSourced, unconfirmedthe pilot's father

Where

Bass Strait, between Cape Otway (Victoria) and King Island (Tasmania), Australia
39.4°S 144.2°E

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