The Australian Transport Safety Bureau (ATSB) has released a preliminary report in relation to a mid-air crash between two sightseeing helicopters on the Gold Coast which resulted in the death of a British couple.

Diane and Ron Hughes, from Neston, Cheshire, died in the collision at around 2pm local time – 4am GMT – on Monday January 2 in Main Beach, not far from Sea World in the state of Queensland.

Queensland Police said the pilot and three passengers had died at the scene, including a pair travelling from the UK – a 57-year-old woman and a 65-year-old man – and a woman, 36, from Glenmore Park, New South Wales.

The report details factual information and the accident’s sequence of events but contains no findings.

The ATSB said the investigation will look closely at the issues both pilots faced in seeing the other helicopter, the nature of radio calls made, operator procedures and regulatory approvals.

The report said the two Eurocopter EC130 helicopters were being operated by Sea World Helicopters (a separate corporate entity to the theme park) on five-minute scenic flights.

One helicopter with a pilot and five passengers on board was on approach to land at a helipad adjacent to the Sea World theme park and the second, with a pilot and six passengers, had just departed a separate but nearby helipad within the theme park when they collided above the Broadwater, the ATSB said.

While video footage taken by passengers in both helicopters on mobile phones contained images of the other helicopter, the ATSB said this does not mean that the other helicopter was visible to either pilot.

Our findings as to the contributing factors to this accident, and the analysis to support those findings, will be detailed in a final report to be released at the conclusion of our investigation

ATSB Chief Commissioner Angus Mitchell said: “The ATSB has released this preliminary report to detail the circumstances of this tragic accident as we currently understand them, but it is important to stress that we are yet to make findings.

“Our findings as to the contributing factors to this accident, and the analysis to support those findings, will be detailed in a final report to be released at the conclusion of our investigation.”

He added: “The investigation will look closely at the issues both pilots faced in seeing the other helicopter.

“We have already generated a 3D model of the view from the pilot’s seat from an exemplar EC130 helicopter which we will use as part of a detailed visibility study to help the investigation determine the impediments both pilots faced in sighting the other helicopter.”

The report says that at 1.55pm the pilot of helicopter XKQ commenced their scenic flight and was climbing over water in the direction of the sandbar near the helipad.

The pilot of helicopter XH9 reported that they did not hear a taxi call over the radio from the pilot of XKQ.

Understanding the helicopter would only get closer, at least one passenger attempted verbal guidance to the pilot. As the verbal guidance did not work... one passenger physically alerted the pilot

“This does not necessarily mean that a taxi call was not made and this topic will be subject to detailed analysis by the ATSB investigation. The pilot of XH9 also reported that they did not see XKQ depart from the park helipad,” the report said.It adds that two passengers on board XH9 spotted XKQ.

“Understanding the helicopter would only get closer, at least one passenger attempted verbal guidance to the pilot.

“As the verbal guidance did not work, and anticipating a potential collision, one passenger physically alerted the pilot.

“The pilot of XH9 later recalled being alerted to the other helicopter by a passenger, but the pilot did not see XKQ approaching prior to the collision,” the report said.

The ATSB will also consider the operator’s procedures and practices for operating scenic flights in the Sea World area and the process for implementing the recently-acquired EC130 helicopters into operation

At a height of about 130 ft, and 23 seconds into XKQ’s flight, the helicopters collided.

Mr Mitchell said the investigation will look more broadly beyond the issues of radio calls and visibility.

“The ATSB will also consider the operator’s procedures and practices for operating scenic flights in the Sea World area and the process for implementing the recently-acquired EC130 helicopters into operation, and will review the regulatory surveillance of the operator and similar operators.”

He said it will be “a complex and comprehensive investigation”, adding that if the ATSB identifies a critical safety issue during the investigation, it will immediately alert the relevant parties so they can take appropriate action.