Passengers who were onboard Qantas flight QF29 from Melbourne to Hong Kong recall mixed scenes from inside the fuselage during the 'stick shaker' incident that left 15 people injured.

Key points: One passenger described the turbulence as a distressing ordeal, says he witnessed people thrown from their seats

One passenger described the turbulence as a distressing ordeal, says he witnessed people thrown from their seats Another passenger did not see anyone injured on the flight

Another passenger did not see anyone injured on the flight The ATSB is investigating the incident

One passenger described distressing scenes of people being "tossed out of their seats" by severe turbulence, while another said it was "nothing out of the ordinary".

Financial adviser Adam Routledge was travelling to Hong Kong to attend the Rugby Sevens tournament.

Mr Routledge said he was sitting "in the thick of the incident" in row 63 and said the experience was "very distressing".

At one stage during the ordeal, Mr Routledge said he feared for his life.

"When the alarms went off and we were dropping, everyone was getting tossed around. I consider myself pretty relaxed, but there was a time there where I thought, 'This is it'."

Mr Routledge described seeing passengers being thrown from their seats during what he called "aggressive turbulence".

"There was basically two parties involved — those who were buckled up, and those who weren't," he explained.

"Those who weren't were unfortunately tossed around very seriously. I was sitting amongst some elderly ladies who were obviously not buckled up, and one in particular behind me actually hit the roof."

In video taken by Mr Routledge after the incident, a staff member can be heard updating passengers over the loudspeaker.

"I think in hindsight the pilot was good, and there were probably some circumstances where the air stewardesses were sort of running up and down the aisles in some ways creating more panic," Mr Routledge said.

"When the alarms went off that was almost scarier than the actual drop itself because they created a scene where you were asking: 'Could there be a fire? Is there a fire?'

"I was speaking to an air stewardess afterwards and she'd been an air stewardess for seven years and said they'd never, ever experienced anything like that."

'I've experienced worse'

Scott Browne, a sales director, was on his way to attend the HKTFC Electronics fair and the China Import and Export Fair.

Mr Browne was seated in economy near the centre of the aircraft.

Sorry, this video has expired Aviation specialist Peter Marosszeky talks about the problems the Qantas flight may have encountered

"There was a big 'dip' you could call it — kind of like being on one of those giant theme park slides," he said.

"It went down and up and down and up again. It did that once and everything was fine … and then it did it again.

"People screamed and yelled a little bit and let out a gasp, as they do when there's a sudden movement, but I've certainly experienced a lot worse."

Mr Browne said that from where he was seated on the aircraft, and after exiting the plane, he did not see any of the 15 injured passengers.

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"The descriptions sounded a bit overdramatic to me and I really just thought the staff did a fantastic job. They re-assured us that we were OK and made sure everyone on board was OK," he said.

"It certainly wasn't a 'near-death experience'.

"Anyone who has ever flown over the equator or into Melbourne on a hot day would have experienced a much bumpier ride," he said.

"These things happen."

Qantas under ATSB investigation

About an hour from their arrival, Qantas pilots detected airframe buffeting — a strong vibration usually associated with separated airflow.

According to the ATSB, an alert known in the industry as a "stick shaker" then occurred, where the controls vibrate as a warning to the pilots that they need to take action or the plane will stall.

The flight crew took manual control of the plane and landed safely at Hong Kong airport, where 15 people were treated for minor injuries.

"Two passengers were transferred to hospital for precautionary medical assessment as a result of their injuries and later released," Qantas said in a statement.