Originally Posted by
Tree
A point of interest:
The 737 rudder hard-overs did not cause the fin to separate.
The regulations for rudder load manoeuvres DO require that you be able to sustain a single full authority control application, so it's not surprising that the 737's didn't suffer fin failures in that event.
Oscillatory/reversing rudder inputs are outside the regulatory requirements, aircraft are not designed to withstand them, and that is unfortunately what happened in this accident.