A delicate salvage operation has begun after two helicopters collided mid-air on the Gold Coast, killing four people and critically injuring three others yesterday.

One Sea World aircraft plunged onto a sand bank face down and the other managed to land, in a busy area near the theme park.

The high tide has swallowed some of the sand bank but once the water recedes, the wreckage will be moved onto a police barge.

Aviation law expert Professor Ron Bartsch has told John Stanley, the Australian Transport Safety Bureau is seeking to work out the cause, rather than attribute blame.

“They’ll be looking at a variety of different conditions.”

“The airspace is extremely congested there.”

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The crash killed four people, the pilot, two British tourists, and a 36 year old woman from Sydney.

Her ten-year-old son remains in critical condition.

A woman and boy from Geelong were also on the helicopter that crashed — they’re in hospital too.

Nine News QLD Reporter Josh Bavas provided an update to James Willis