Four people died when the two Sea World choppers collided above the Gold Coast Broadwater in January 2023 during the busy summer holiday season.
Almost three years later, coroner Carol Lee opened an inquest in Brisbane on Monday into 11 critical issues surrounding the devastating crash.
Counsel assisting Ian Harvey played videos of the collision as part of his opening address.
Multiple passengers used their phones to film one of the helicopters taking off, followed five minutes later by their own chopper's flight on a bright sunny day above turquoise water.
Just 25 seconds after the second helicopter took off, it collided with a fellow Sea World-branded chopper at an altitude just under 40 metres.
At least one passenger in the second helicopter is shown on video trying to get a pilot's attention and point out the other aircraft is closing in on them.
"It's inescapable that neither pilot saw the other pilot's helicopter," Mr Harvey said.
"How could that happen? They were two experienced pilots in modern, relatively sophisticated helicopters."
Security camera footage showed the helicopter piloted by Ashley Jenkinson crash onto a sandbar near Sea World and roll onto its roof.
Mr Jenkinson, 40, died as well as British newlyweds Ronald and Diane Hughes - aged 65 and 67 - and Sydney mother Vanessa Tadros, 36.
Ms Tadros' husband Simon was present at the inquest in Brisbane on Monday.
CCTV on a nearby helipad also captured the helicopter piloted by Michael James come to a controlled landing near the first chopper's crash site.
Mr James and nine passengers across both aircraft were injured, most of them seriously.
Last year Mr James died from an unrelated medical condition, Mr Harvey said.
Pilot training and safety systems by the company operating the helicopters - which provided short flights for tourists and theme park guests - will be among a string of issues to come under scrutiny at the inquest.
The coronial probe comes months after a damning safety bureau report into the mid-air collision.
A litany of factors led to the crash including limited visibility, failed radio transmissions and a lack of safety protocols, the Australian Transport Safety Bureau's final report revealed in April.
Mr Harvey said at the time of the crash the volume of flights had been double for the peak holiday season.
"It was one of the busiest air corridors in the country," he said.
The inquest will look at how the crash occurred and its most likely cause, including whether safety management systems involving ground and air crew were adequate and appropriate.
The two helicopter pilots could not communicate with each other by radio and did not have an electronic tablet map to track each other's movements, Mr Harvey said.
"Management intended to install the equipment. It had arrived. They needed to source suitable mounts," Mr Harvey said.
The inquest is due to run for three weeks.
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