Ah Catchpoint afew minor corrections.
Teh Alaskan aircraft was a DC-9 type derivative (MD-80 or similar) and appears to have lost its hoirizontal stabilizer after a trim screw jack failure allowing the whole assembly to pivot about its aft attach point and separate from the aircraft - nothing to do with 737 rudder failures.
The 737 rudder servo has undergone modification and there is a program to retrofit. Pilots have been trained and use procedures and techniques to overcome an upset caused by possible erroneous rudder inputs in the meantime.
Hope this helps.
