I'm asking this question having watched a documentary about Northwest Flight 85 in 2002, during which a 747-400 experienced a lower rudder hardover at an angle of 17 degrees to the left.
The pilots were able to recover by taking over manual control and using the ailerons, the upper rudder and asymmetrical engine thrust to oppose the forces being generated from the lower rudder hardover.
During the doco, I believe the pilot in control immediately turned off the autopilot as he realised it wasn't going to be able to recover from the initial roll.
I just wondered if an autopilot would be able to recover from such an event - i.e. is it technically possible? It seems like the sort of thing an autopilot could achieve easier than a pilot, assuming it was programmed correctly.