Originally Posted by
Sailvi767
It’s also unlikely a rudder hard over would cause a upset as rudder travel is limited by dynamic pressure at cruise speeds. Rudder hardcovers normally are a problem at low speeds where full throw is available.
Correct. The accidents after the rudder hard over with the 737 happened at rather low speed during the approach. At higher speeds there is enough aileron authority to overcome the rolling moment caused by the rudder. One of the "fixes" was to apply higher speeds for flaps 1-10 to avoid the speed envelope where a hard over could not be counteracted by the ailerons (called crossover speed).
There were also some incidents with the rudder PCU that happened in cruise flight. They were recoverable.