Originally Posted by
wonkazoo
I'm sorry, I'm trying to pick my jaw up off the floor. The 737 has no redundancy in it's rudder control system?? I've had a rudder cable failure- trust me when I say it can end very badly!! Can any (ahem) 737 Driver confirm that this is in fact accurate, that there is either no or a lack of redundancy in the 737's rudder??
If that is true that is the most shocking thing I have read about aviation in a very long time- and that the airplane was granted its STC just three years ago makes this even more shocking.
This caught my attention as well. I'm not sure exactly which part of the system they are talking about. From my FCOM:
Each set of rudder pedals is mechanically connected by cables to the input levers
of the main and standby rudder PCUs. The main PCU consists of two independent
input rods, two individual control valves, and two separate actuators; one for
Hydraulic system A and one for Hydraulic system B. The standby rudder PCU is
controlled by a separate input rod and control valve and powered by the standby
hydraulic system. All three input rods have individual jam override mechanisms
that allows input commands to continue to be transferred to the remaining free
input rods if an input rod or downstream hardware is hindered or jammed.
My reading is that the Captain and First Officers rudder controls are completely independent (though linked) systems. As with virtual all controls in modern airliners, one side can override a jam on the other side.
That being said, Boeing's management of the MAX program is looking more dismal with each passing day.