Possible causes
Whilst flying back to Liverpool yesterday from Carcassonne the plane suddenly rolled (approx 45deg) to the left quickly enough to cause the cabin crew to stumble and grab on something. The plane then recovered and all seemed normal. Whilst we disembarked two mechanics were looking at the fan blades inside the left hand engine. Is it possible that an engine surge caused the plane to roll suddenly or is it most likely a wake encounter?