The ATSB has finalised its investigation into the loss of a Cessna 210 near Darwin in April this year.
VH-EFB crashed into the water after encountering thunderstorms en-route from Bullo River to Emkaytee.
The aircraft was one of a several traveling as a group, and disappeared off Cape Ford after deciding to track coastal. Other aircraft took an in-land route.
"The pilot of the Cessna 210 departed at about 1415 with three passengers to track via the coast," the report states.
"The pilots in the group were communicating by radio on a discrete frequency and the Cessna 210 pilot was heard to report at about 1510 that he was approaching Cape Ford and the weather ahead was gloomy, or words to that effect. That was the last radio transmission from the pilot.
"When the aircraft did not arrive at Emkaytee a search was initiated. Bodies and a small amount of wreckage were found on the southern shoreline of Anson Bay, about 10 km south-east of Cape Ford. There were no survivors."
Although the reason for the impact with the water was not determined, the ATSB attributes the accident to a thunderstorm.
"During the flight from Bullo River to Emkaytee, the pilot continued to track along the planned coastal route towards a thunderstorm, probably encountering conditions such as low cloud, reduced visibility and turbulence, and as a result of one or more of those factors the aircraft descended and collided with water."
The full report is on the ATSB website.