ATSB investigators to examine Rottnest seaplane wreckage in search for cause of crash

By Phoebe Pin and Rebecca Trigger for the ABC

Investigators are hopeful wreckage to be recovered from a seaplane that crashed and killed three people near Rottnest Island could hold clues about the cause of the tragedy.

Police divers worked through Tuesday night to recover the bodies of two tourists and the aircraft's pilot, who has now been identified as 34-year-old James Wong.

Another three passengers of the Cessna 208 were injured, while another was unscathed.

Attention has now turned to understanding what went wrong before the plane hit the water.

Vital seconds

Speaking from Rottnest Island on Wednesday, Australian Transport Safety Bureau (ATSB) chief commissioner Angus Mitchell said the first priority was to recover the submerged fuselage, cabin and engine.

"We do quite often get a lot of information from onboard aircraft, even after they've been in catastrophic collisions," he said.

"We already know there is a lot of footage that's in the hands of both media and the police, and we use all of that to piece together what happened.

"We only have a number of seconds of the aircraft was in flight, so we'll be focusing very heavily on what occurred in those seconds."

Mitchell said investigators from the ATSB - the national body responsible for investigating transport-related incidents - would also assess weather conditions, pilot history and training, the aircraft's maintenance logs and witness statements as part of the probe.

"There's a lot of things that happen before these flights take place, and there's processes that we get digital records of, so we'll be looking at all that information to see what is applicable to this particular incident and what does it mean," he said.

Police initially said the plane - which was built in 2016 and was recently acquired by Swan River Seaplanes - struck a rock formation in Thomson Bay before it hit the water at 4pm AWST on Tuesday.

Later, the ATSB said it had received reports the plane collided with the water during take-off.

On Wednesday morning, WA Premier Roger Cook said it had not been confirmed whether the plane had made contact with the rocks before crashing.

Plane 'tried and tested'

After assessing vision of the seaplane in the moments before it crashed, aviation safety expert Tim Collins said there was "nothing unusual" to indicate a tragedy was about to occur.

He said the incident could be the result of human error.

"The pilot potentially rotated too early with insufficient airspeed, and that's allowed the airframe, or the wing, to stall," he said.

"That's why it's dropped a wing and flipped into the water."

Collins said the wrecked Cessna 208 was one of more than 3000 built for use in freight transport and light passenger operations.

He said the plane's airframe and engine were "extremely reliable and very well tried and tested".

"In terms of a maintenance or mechanical issue, it's always possible, but my professional opinion here [it] would be highly unlikely," he said.

In a statement, Swan River Seaplanes director Kristy Bailey described Wong as a "talented and dedicated pilot who was an integral and deeply cherished member of our team".

Wong would have been required to undertake additional training before being allowed to operate a seaplane, according to Collins.

"In order to gain a float plane endorsement, you have to satisfy an examiner that you're competent to fly the aircraft on and off the water and operate the aircraft as a float plane," he said.

"It's not a tick and flick box, it's something where you actually have to go and train."

Mitchell said the ATSB would aim to deliver its preliminary report in the next two months, with findings and recommendations expected at a later date.

"Certainly, our job is ahead of us now, over the next weeks and months, to uncover exactly what went wrong and what we can recommend to ensure that these things are a lot less likely to happen into the future," he said.

-ABC