Qantas vibration problem..
 

"About 15 minutes into the flight, the flight crew picked up on some excessive vibration in the number four engine," a Qantas spokesman said.

Explosion halts Qantas flight Today's News - The Mercury - The Voice of Tasmania

That wasn't very well contained. At least they had the good judgement to turn around rather than pressing on to Sydney :rolleyes:

Qantas Engine Failure
 

Video;