Hi HN39;
Thanks for the reply. I will answer the PM in due course.
Looking at the Yaw Damper trace, I believe that the maximum rudder angle allowed by the Yaw Damper (+/-4°) was not exceeded, but whether the damper was acting correctly is another matter.
The DA displayed by the TLU is rather puzzling. Perhaps the TLU angle doesn't represent the actual rudder angle, but there doesn't seem to be a valid reason for that to happen. As the AMM doesn't shed any light on the situation, we may just have to wait for the BEA to explain exactly what was happening.
As you have already pointed out, if the deviations shown in the TLU traces are to believed, where did this Mach data come from?
Having searched the various definitive sources and found nothing, I reverted to the Cathay Pacific notes originally compiled by Andy Tracey and came up with this for
Yaw and another for
ALT-2.
EDIT : Basic control schematic
