The veteran pilot killed when a light plane carrying five passengers crashed into the Direct Factory Outlet shopping centre in Melbourne yesterday was already under investigation after a "near-collision" in 2015.
Max Quatermain was piloting the Beechcraft B200 King Air aircraft when it crashed just after 9am yesterday, causing a large explosion.
Mr Quatermain was the subject of an 18-month investigation by the Australian Transport Safety Bureau (ATSB) following a flight in Mount Hotham in September 2015, The Age reports.
At the time, he was reportedly flying a small aircraft with a faulty GPS and came within 1.8 kilometres horizontally and 90 metres vertically to another aircraft.
Mr Quatermain faced possible suspension of his licence over this incident after it was declared "unsafe".
The investigation is yet to be resolved, the newspaper reports.
However friends have rallied around the late pilot, remembering him as a "true aviator" with a "gentle, caring nature".
Mr Quatermain had been a charter pilot for more than 38 years and has a "impeccable safety record", according to his company's website.
Aviation expert Geoffrey Thomas told 9news.com.au the plane recently passed a safety check and that Mr Quatermain was re-endorsed as pilot.
A friend and fellow pilot said Mr Quatermain had been flying for a number of carriers for most of his life.
"Only in the last five or ten years he had his own little charter business for people on holidays.
"King Island has been a big hot spot lately, about a dozen flights there a day," the friend told nine.com.au.
Mr Quartermain's four passengers were US citizens, who were headed to Tasmania's King Island's on a golf trip.
Three of the passengers have been identified as Greg De Haven, 70, Russell Munsch, and Glenn Garland.
Social media posts from friends and relatives of passengers believed to be on board the aircraft are beginning to surface.
The plane had just taken off from Essendon Airport when it made two mayday calls shortly before crashing into the rear of DFO Essendon near the Spotlight and Focus on Furniture stores.
Victorian Premier Daniel Andrews today called the crash a "catastrophic" event.
"This is the worst single aviation accident Victoria has seen in 30 years," he said.
He praised the work of police and around 90 firefighters who extinguished the fireball and managed to quickly shut down the area to avoid injuries inside the centre.
Victoria's Police Minister Lisa Neville this morning confirmed five people were on board when the plane struck.
"It appears to be a very, very tragic accident that's happened out there," she said.
The Australian Transport Safety Bureau sent four investigators to the site yesterday to determine the cause of the crash.
ABC radio caller Jason was in a taxi when he looked out the window and saw what he thought was a twin-propeller plane.
"I saw this plane coming in really low and fast. It went just behind the barriers so I couldn't see the impact but when it hit the building there was a massive fireball," he said.
"I could feel the heat through the window of the taxi, and then a wheel - it looked like a plane wheel - bounced on the road and hit the front of the taxi as we were driving along.
"We kept driving and there was big fireball behind us."
A Spotlight store manager told 9news.com.au there were 20 staff members inside at the time of the crash, but said all were accounted for.
"The staff were in the premises when it happened. It hit the warehouse dispatch area at the back of the store. We can’t confirm if anyone was in that area at the time but no staff were injured. They were taken away for counselling," she said.
Did you witness the crash? Email contact@9news.com.au