Originally Posted by
silverstrata
Think you are wrong there. Unlike all other aircraft, the 737 had a single rudder PCU. (A bit like MCAS only using one AoA sensor - you would have thought Boeing would have learned by now that two is the minimum).
The 737 rudder PCU was made into a dual system because of several incidents and two crashes, not because of Cat III operations. Seem to remember that one of those incidents was on a BA 747, which captured the error on data recorders (the 747 used the same PCU for the elevators).
https://en.wikipedia.org/wiki/Boeing_737_rudder_issues
Silver
Yes indeed you are correct and I did remember about the US air and other possible PCU problems I just plain forgot to add this before my brain fart, but thanks anyway
I believe that the flap tracks on the NG weren't good enough when they first designed because flap 40 position had too much axial movement.