Gold Coast helicopter crash: Pilot flying Kiwi survivors didn't see or hear anything from second helicopter - report

A key factor in the deadly helicopter crash on the Gold Coast has been revealed. 

Australia's Transport Safety Bureau says the pilot flying the Kiwi survivors didn't see or hear anything from the second helicopter when it took off. 

A Kiwi passenger on board the deadly helicopter crash on the Gold Coast captured the footage of not only what the pilot couldn't see but what he apparently didn't hear. 

"He does not recall hearing that taxiing call but that doesn't mean it wasn't made," Australian Transport Safety Bureau's chief commissioner Angus Mitchell said.

A crucial call that would have come from the second helicopter ready to take off. 

"He did see it preparing for flight," Mitchell said.

Unfortunately, that was all. 

"The pilot of the arriving helicopter did not see the other helicopter actually depart the helipad," Mitchell said.

Investigators said just 23 seconds after the second helicopter took off the two helicopters collided.

Four people on board the first helicopter that took off died.

Miraculously, everyone on board the second helicopter, including two Kiwi couples, survived. "This certainly is a tragic accident," Mitchell said.

But investigators believed the accident was preventable. 

"I certainly wouldn't go as far as saying it was a freak accident," Mitchell said.

The preliminary report revealed the company operated five-minute sightseeing flights near SeaWorld.

The helicopters fly counterclockwise using different helipads that are 220 metres apart. 

From witness accounts and a dozen iPhone videos, investigators have built a 3D model of the scene recreating what the pilots could see during the fatal crash.

But the investigation is not just looking at individuals.

"We will look at every part that may have contributed not simply honing in on visibility or radio calls," Mitchell said.

The final report will answer what happened. 

But it will be the police who decide who if anyone will be held responsible.