Bateman's Bay Marine Rescue volunteers had just finished a training exercise, searching for an imaginary crashed plane, when the real thing happened on Sunday afternoon.
The marine rescue regional co-ordinator for the Illawarra, Bruce Mitchell, drove to Batemans Bay to help with the operation after the light aircraft came down about 12.30pm.
The plane crashed into the ocean off Barlings Beach south of Batemans Bay, and a sea and air search began shortly after.
Graham White, believed to be in his 60s, was found floating in the water later that day.
He could not be revived.
A second man remains missing. Both have been described as popular within the local community.
Mr Mitchell said Marine Rescue boats had just returned from the training exercise when the crash happened.
He said visibility and weather conditions had so far aided the search.
"They could just make out the wreckage on the bottom and also they ran the sounding equipment over it - there was something of a reasonable size there," he said.
The search has focused in an area of water about 22 metres deep, Mr Mitchell said.
"From the wreckage I saw brought back in last night, it must've been a hard impact."
Police divers from Sydney were searching the wreck to locate the body of the man still missing on Monday afternoon.
Marine Rescue boats were on standby, while the police boat from Eden was being used on the water.
Five Marine Rescue boats were used during the initial search.