CANBERRA, April 13 (Xinhua)​- Fifteen passengers on a Qantas flight from Melbourne to Hong Kong were injured after a "stick shaker" incident occurred on a Boeing 747 jet last week, the Australian Transport Safety Bureau (ATSB) confirmed on Thursday.

"Stick shaker" is a term used to describe when the control stick shudders to warn those in control of the plane that a stall could be imminent. It's a phenomenon one aviation expert described as "extremely rare" but "very serious."

In a statement released on Thursday, the ATSB said it would be conducting an investigation into the incident, which occurred last week.

"The ATSB is investigating a stick shaker activation involving a Qantas Boeing 747, VH-OJU, 110 kilometers southeast of Hong Kong on 7 April 2017," the statement said.

"While holding at flight level 220, the flight crew received a stick shaker activation and detected airframe buffeting. The flight crew disconnected the autopilot and maneuvered the aircraft in response. Fifteen passengers received minor injuries.

"As part of the investigation, the ATSB will interview the flight crew and gather additional information."

A Qantas spokesperson confirmed the incident late Wednesday, and said in addition to the ATSB investigation, the airline would conduct its own review of the stick shaker incident

"Customers on QF29 experienced unexpected in-flight turbulence when travelling from Melbourne to Hong Kong on Friday. We notified the ATSB of the occurrence, and our own teams are also reviewing the event," the spokesperson.

Meanwhile, aviation expert Geoffrey Thomas told News Corp that a stick shaker was an aerodynamic stall which occurs when "the angle of attack of the wing increases beyond a point such that the lift begins to decrease." He said they were both "extremely rare" and "very, very serious."

"The airflow over the wing begins to separate and it breaks up. There is a sudden decrease in altitude, which is why some passengers may have been injured," Thomas said on Thursday.

The ATSB has said that a report into the incident will be released "within several months."