Australian officials said that the reason for the catastrophic mid-air collision between two helicopters on the Gold Coast is still being investigated.
Two Australians and a British couple died in a crash on Monday in Queensland near the Sea World resort.
Three more victims of the crash, in addition to the two children, suffered serious injuries.
Officials claim that the event took place less than 20 seconds after one chopper took off from a sandbar and collided with another that was approaching land.
"What we do need to know quickly is what was going on inside those two cockpits at that time," said Angus Mitchell, commissioner of aviation safety.
The ascending helicopter, which collapsed seconds after its main rotor blade struck the other aircraft's cockpit, was where all of the deaths and major injuries took place.
The second helicopter landed upright on the sandbank. Five of the six people on board sustained minor wounds.
The landing was an "incredible performance," according to Mr. Mitchell, considering that the helicopter was destroyed "where the pilot was sitting."
"We are incredibly fortunate that we are not standing here with much more casualties," he told reporters on Tuesday.
The two married Merseyside residents Ron and Diane Hughes, aged 57 and 65, who died in the UK have relatives in Australia.
According to Australian media, Vanessa Tadros' 10-year-old son was one of the survivors who was taken to the hospital in critical condition. Vanessa Tadros was 36 years old.
The fourth fatality was local Sea World Helicopters pilot Ashley Jenkinson, 40. The Brisbane Times reports that he was born in England.
Ritchie Gregg, a close friend of Mr. Jenkinson, called him a "silent hero" and a "gentle giant" to the BBC.
From the bushfires a few years ago to the flood waters last year, the witness said, "he was always out there helping the people."
"What we achieved with the NSW floods last year was without a doubt one of the pleasures of my life. If not for him, many people might not have gotten the assistance they did.
Devastating floods struck New South Wales last year, particularly those around Lismore.
According to the police, a 33-year-old woman with serious injuries was hospitalized but was in stable condition, while her nine-year-old child remained in critical condition. Along with the 10-year-old child, they were the sole survivors of the helicopter accident.
Both helicopters were leased by SeaWorld, one of the several well-known amusement parks on the Gold Coast, to offer flights for visitors. According to the company's owner, Village Roadshow Theme Parks, who also extended their condolences, Sea World Helicopters is an independent operator.
It's difficult to accept that despite how beautiful and serene that part of The Broadwater on the Gold Coast is, it is now the scene of a serious incident. The lake is very clean, and there are boats and jet skis everywhere.
Just across the street lies the sandbank where the helicopter crash took place. The tide previously made it impossible for authorities to remove the chopper wreckage. Several police boats are still there, and detectives are searching the area for further proof. At least three divers have been seen peering down at the ocean bottom.
It's not far from the Sea World amusement park, where riders may be heard. One of the helicopters was trying to land, and while it hovered over the park, a witness reportedly feared one of the aircraft may crash into the crowd. Thousands of individuals have come during this hectic Christmas season with their children.
"If you know the Gold Coast, you know Sea World helicopters," a resident said to me. Many tourists ride them for quick trips throughout the area since they are a common sight.
Why one helicopter took off so near to another that was trying to land is the most crucial problem that the investigators are still trying to answer.
The ATSB said that it would speak with witnesses and extensively investigate the area, helicopters, video, and other evidence before deciding as to what caused the tragedy. Any potential witnesses were asked to come forward.
At about 14:00 local time (04:00 GMT), boat operators reportedly reacted immediately to the event by performing CPR and other first aid procedures.
Tidal changes reportedly made it difficult for investigators to get access to the sandbank and consequently gather evidence.
The preliminary report from the ATSB is anticipated in six to eight weeks.
The "terrible and horrific tragedy," according to Prime Minister Anthony Albanese, left the country in disbelief.
According to the UK Foreign Office, it is assisting the victims' families and will stay in contact with local authorities.