WCSH-TV recently reported on a serious engine problem that forced a Southwest flight to return to Love Field in Dallas on Nov. 17.
A Southwest spokeswoman told the station that "our pilot did notice a vibration in the right engine." Some passengers described it a little differently – they said the engine, well, exploded, according to the FlightStory aviation blog. Which would explain the big hole in the engine casing.
I guess you could describe an explosion as a whole lot of vibrations, but I think this discrepancy may be more than semantic.