He said compensation could be sought for the nervous shock of the crash and dependency if relatives were financially reliant on the men killed.
Texan retirees Greg De Haven, Russell Munsch, Glenn Garland and John Washburn died on impact with Mr Quartermain when the plane hit the DFO.
They had been in Australia on a golfing "trip of a lifetime" with their wives, who were not on the flight.
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• Essendon crash pilot's seven 'mayday' calls
According to the report, Mr Quartermain made seven mayday calls before his Beechcraft King Air crashed but anything else uttered in the last moments on-board remains a mystery because the black box failed.
All the recovered audio was from a previous flight on January 3, 2017.
Investigators will now look at the propellers to determine the blade angles at impact, their pre-impact condition and to assess the impact damage.
The ATSB will release a final report in about 12 months.