Read more about the story on CNN affiliate KTVU.
San Francisco, California (CNN) -- A Qantas Airlines flight bound for Sydney, Australia, from San Francisco, California, was forced to return to San Francisco early Tuesday after experiencing problems with one of the plane's engines, the airline said.
Flight 74, with 212 passengers and 18 crew members, left San Francisco at about 11:30 p.m. Monday, said Qantas spokesman Simon Rushton.
About 45 minutes into the flight, he said, the plane's No. 4 engine experienced some vibrations and mechanical problems. Pilots shut the engine down and sought clearance to return, Rushton said. The flight landed at about 12:45 a.m. Tuesday without incident, he said.
Mechanics determined the engine needs replacing, but do not know the cause of the problems, Rushton said.
"We were about half an hour into the flight and there was a very strong shudder on the right-hand side of the plane," passenger Neil Duffy told CNN affiliate KTVU-TV. "It wasn't turbulence. It seemed that there was some pretty serious damage. People on the right-hand side of the plane seemed very shocked. Apparently, there were flames coming out of the engine."
"I heard a thud, a bump and the plane veered off to the left," passenger Nolan Goldstein told the station. "It was very uncertain for a period of time until the captain announced that we had an engine that blew up. ... It was a real uncomfortable vibration at first and then the plane began to shake a bit."
Duffy told KTVU the captain "came on and assured everybody that the plane was still relatively safe. [He said] there was serious damage in one of the engines. We jettisoned some fuel and turned around. The captain made a very good landing. We all cheered."
All the passengers were put up in hotels, Rushton said. The airline was working on getting them on other flights, he said.
CNN's Rosalina Nieves contributed to this report.