Originally Posted by
barit1
Without having the reference before me, I believe that the rudder limiting approaches between Boeing and Airbus are quite different. IIRC Boeing reduces rudder gain (i.e. a given force on the pedals gives less rudder displacement as airspeed increases); whereas Airbus maintains a fixed gain but limits the pedal travel, thus less pedal force is needed to drive the rudder to the stops.
Pretty much exactly correct, according to my old teacher's RISK bulletins.
Also worth noting is that the A300 series has a very powerful rudder, with the moving parts taking up a significant percentage of the vertical stab's total area. The video from AA's training sessions implies that the primary focus was on the DC9/MD80 series, which was understandable given that it made up a significant portion of AA's fleet at the time. I don't have the relative sizes to hand, but I'd imagine that the active rudder section of the DC9's vertical stab would be significantly less.
While we will never be 100% sure, the PF was expecting significant wake turbulence and may have perceived the shortening of the rudder pedal's travel to have been a consequence of the JAL 747's wake rather than the rudder limiting kicking in. Either way no matter what aircraft was being flown, repeated rudder reversion in a sideslip would likely lead to the same structural failure that was seen in this incident.
IMO there were lessons to be learned by pilots, manufacturers and airlines as a result of the issues the AA587 accident brought to light and it's a shame that some of those lessons have been submerged due to territorial disputes (AA as a corporate entity, AA's pilots and Airbus were all a little to blame there).