On this day, 52 years ago, a tragic helicopter crash at Circular Quay in the middle of Sydney's CBD killed three people and changed Australian aviation.

"Imagine flying over Sydney Harbour on a beautiful sunny day, and then the world starts to spin out of control," historian Peter Hobbins told 7.30.

On board were cameraman Frank Parnell, ABC producer Patricia Ludford and pilot James Reilly.

Helicopter pilot Jim Reilly while serving with the RAF in Malaysia. ( Supplied: Bruce Reilly )

It's thought that Mr Parnell kept filming, even in the distressing moments before his death, and the footage was later found amongst the debris of the crash.

The accident was witnessed by many bystanders in the city and widely reported on the news, creating increasing pressure for something to be done to ensure safe flying.

'The tragic story that I can always recall'

Ross Symonds was called in to read the newsflashes about the chopper crash. ( ABC News )

Veteran news presenter Ross Symonds, who presented ABC News in Sydney at the time, still vividly recalls the tragedy.

"The ABC hired this helicopter to take some documentary footage of the harbour and they planned to land on the top of the AMP building," he told 7.30.

"The helicopter ran into trouble and lost the rear rotor and it just started spinning."

Mr Symonds was at home that day when he received the call.

"I got a call from [an ABC colleague] and he said: 'Mate we've just had a big tragedy'. It was a helicopter crash," he said.

"It was one that we were hiring and our cameraman has been killed in it."

He was called in to do the news flashes.

The next day the footage shot by Mr Parnell was discovered.

Cameraman Frank Parnell. ( ABC News )

"The camera was found in the crash but nobody thought to look for the film," Mr Symonds said.

"It was only when we contacted the film hire company, where we hired cameras, that they found this little package that was in a rubbish bin, would you believe.

"They said, 'oh yeah, we found this in the wreckage and just dumped it', and they pulled it out of the rubbish bin and there was the film that had been shot from the interior while the helicopter was crashing.

"It was just amazing stuff."

A bad year for Australian civil aviation

Historian Peter Hobbins says the helicopter crash had a major impact on air safety. ( ABC News )

The incident was not the only aviation tragedy in Australia in 1966.

Earlier that year, 24 people died when a plane crashed in Winton, in central-west Queensland.

"This was a huge story in late 1966," said Peter Hobbins, historian at the University of Sydney.

"Not only was it front-page news in newspapers around the country, but it was also featured in news reels and television reports around the world."

"The prominence of a crash right over Sydney on a busy Saturday afternoon before Christmas, and the fact that we could feel what it must have been like to be inside the helicopter or to be a witness on the ground watching these people obviously about to die, had a major impact on our culture and on the way we continued to think about air safety in Australia."

After the crash, aviation safety authorities changed the laws to restrict single-engine aircraft and helicopters access over built-up areas and instead create air corridors over waterways and coastlines where possible.

That rule still applies today.

Producer Patricia Ludford. ( Supplied: ACP )

And while the accident behind the rule change may have been forgotten by many, it's something that Mr Symonds will always remember.

"It is just something that has remained in my memory all these years," he said.

"It's so long ago but for me it's just like yesterday."