This photograph was taken off Cape Otway 20 minutes before pilot Frederick Valentich went missing. Picture: Supplied INVESTIGATORS have shed new light on one of Australia’s greatest aviation mysteries. Almost 36 years to the month that Victorian pilot Fred Valentich vanished without a trace, an independent researcher says there is evidence suggesting the 20-year-old’s Cessna was spotted in the sky over South Australia — attached to a UFO.The Victorian UFO Action group wants help to identify a farmer near Adelaide who reportedly witnessed the 30m craft hovering over his property the morning after Mr Valentich went missing.It is claimed...