Investigators today said the Robinson R44 helicopter was seen hovering less than 10m off the ground after takeoff when it lost control and crashed at Jaspers Brush on Saturday.

Australian Transport Safety Bureau (ATSB) investigators have spoken to witnesses and expect to finish their on-scene work today.

The horror crash, south of Berry, claimed the lives of Andrew Wight, 52, and 60-year-old Mike deGruy.

The downed chopper was ablaze when emergency services arrived on the scene about 4pm, police said. The fire was so intense witnesses said helpers struggled to even approach the wreckage.

The victims had not been formally identified yesterday as police prepared a report for the coroner.

The ATSB will also examine the wreckage and seized maintenance records at the weekend. Bureau duty officer Joe Hattley said a final report may take up to nine months.

Shoalhaven councillor David Bennett, who witnessed the accident, said the tail rotor struck the ground causing the helicopter to crash and burst into flames.

“It was no more than 15 to 20 seconds from that happening and the people on board being incinerated,” he said.

“It was pretty instant.”

Anthony Bowie, who owns the airstrip at Jasper’s Brush and spoke to witnesses, said the accident was all over in 40 seconds and claimed the chopper was less than a metre off the ground before it crashed.

‘‘The helicopter got about 2-3 feet off the ground. It started initiating a left-hand turn when there was a loud bang,’’ he said.

‘‘The helicopter reared nose up and slammed its tail into the ground.’’

He said intense heat kept rescuers from the wreckage.

Mr Wight and Mr deGruy, both renowned documentary film-makers, were working on a new documentary with National Geographic and James Cameron, director of Hollywood blockbusters Titanic and Avatar.

Mr Cameron paid his respects to the pair yesterday.

‘‘Their deaths are a tremendous loss for the world of underwater exploration, conservation, and film-making,” he said.

(with John Hanscombe)