originally posted by bearfoil ...
The report states the RTLU was removed and tested; it was found to be "stopped" at 4 degrees each side of center.
The RTLU was tested and found locked at +/- 7.9° which is a value consistent with FL350 and M0.80 (could also be consistent with other altitudes and speeds ). A schematic of the basic rudder control follows:-
The mechanical limit is such that when the feedback angle from the rudder exceeds that set in the RTLU, further application of hydraulic pressure is inhibited to the rudder rams. Failure of the hydraulic system following impact equals loss of hydraulic rigidity, allowing the rudder to swing freely and beyond its normal maximum limit of +/-31.2°.
Now, the above is my understanding of the control system, and as usual I may be wrong.
mm43