Pilot under investigation
The pilot of the plane which crashed into a shopping mall in Melbourne on Tuesday morning, killing five on board, was under investigation over his "unsafe" flying - which another pilot says nearly killed 18 people.
Sixty-three-year-old pilot Max Quartermain, the owner of the charter company that arranged the plane trip, died in the crash.
At the time of the crash the Australian Transport Safety Bureau had placed him under investigation after he came within 90 metres vertically and 1.8 kilometres horizontally of another plane in an earlier incident.
The other pilot told the bureau that Mr Quartermain's actions were "unsafe".
"If this event did result in a mid-air collision, two aircraft would have been destroyed and 18 people would have been killed," he claimed in his report.
However the draft investigation report was delayed for over eight months because of the "competing priorities and workload of the investigator in charge", the Australian Transport Safety Bureau says.
"Completion of the draft investigation report has been further delayed by the involvement of the investigator in charge on other aviation safety investigations and tasks."
Mr Quartermain faced the possible suspension of his aviation licence and referral to the Civil Aviation Safety Authority over the near collision.
The report into the incident is now expected to be finalised by May 2017.
Eyewitness accounts of the blaze
It's understood the plane took off just before 9am (local time) carrying four American golfers on a charter flight scheduled to take 45 minutes. It reached 50m altitude and then suffering engine failure.
Steven Leane, Victoria's Assistant Police Commissioner, says the pilot tried to turn back after realising there was a problem with the engine, but couldn't.
Authorities confirmed the pilot sent a mayday call before the crash, describing a "catastrophic engine failure".
Witnesses recalled seeing a fireball, explosions and billowing black smoke.
"All we could see was just a big fireball and what was left at this point, I mean there's pretty much nothing left on impact," witness Ash Mayel says.
Another witness said he saw the plane nose dive into the building.
"There was nothing we could do. The flames were just too big and too high," he added.
Paul Edwards also saw it unfold and described the sound of the plane crashing as like an atomic bomb going off.
"I was driving to work and it's surreal because it was like an atom bomb going off right next to you. You don't realise what you're actually witnessing.
"Then a massive explosion and a wheel went flying right into Tullemarine [Freeway ... if there's any saving grace for this it's that the plane didn't go onto the freeway."
The crash has left a large hole in the roof of the shopping centre.
There are more than 100 stores at the outlet mall, but it was not due to be opened to the public until 10am local time - an hour after the accident.
Major roads nearby, including the Tullamarine Freeway were closed, but have since been re-opened.
The airport, which is largely used for freight, has been closed until further notice.