A China Eastern flight bound for Shanghai was forced to turn back to Sydney due to a mid-air emergency, a spokeswoman for the airline said on Monday, with pictures showing a gaping hole in the casing of one of the plane's engines.
The plane, which data from flight tracking website FlightAware showed was an Airbus A330-200 twin jet, landed without incident and there were no injuries, said Kathy Zhang, a general manager at China Eastern Airlines.
"The crew observed the abnormal situation of the left engine and decided to return to Sydney airport immediately. All passengers and crew members were landed safely," she said.
Huge hole in engine casing
Photographs published by several Australian media outlets showed a large gash well over a metre long in the casing of the plane's left engine.
Australian Television station Seven News reported that passengers heard a bang shortly after Flight MU736 took off and could then smell burning before the flight turned back.
"We went up in the air and all of a sudden we heard this noise ... it kind of smelt like burning. Oh, I was scared. Yeah, I was really scared. Our group was terrified," one unidentified passenger told Seven News.
Another passenger, identified only as Eva, said the cabin crew tried to calm passengers and told them to fasten their seatbelts after a noise was heard.
A spokeswoman for Rolls-Royce, which manufactured the plane's Trent 700 series engines, said in a statement: "We are aware of the incident and will be working closely with our customer and relevant partners to understand the cause of the issue."
The Australia Transport Safety Bureau said it was investigating the incident.
China Eastern's Zhang said a comprehensive investigation would involve aviation authorities from Australia and China.
"The engine for the aircraft is a big issue so we need to investigate with the governments, with the Rolls Royce company and with our headquarters as well," she said.