Originally Posted by
stoneeye
As someone with just offering a drivers license and therefore without any deeper knowledge about flying or planes I would like to ask a question regarding the behaviour of the lower and upper part of the rudder of that A380.
Look at the video.
Through approach the pilot or the autopilot manages to slip down smoothly and hold the course and so on with almost just using the lower part of the rudder. A split second before touch down the upper part of the rudder kicks in too and then the brutal force of that giant rudder working as a whole lets the plane swing heavily to the left.
Why is that? It seems that this kicking in of the upper rudder and its influence on the plane`s direction comes surprisingly to the pilot. Also when he tries to countermanage the direction it seems that he is not overreacting but does not know or expect that both upper and lower rudder work together. Therefore that PIO.
Thanks in advance.
I agree. During the approach the upper rudder is not moving in sequence with the lower rudder until a split second prior to touchdown when the upper rudder can then be seen to deflect to the left and therefore increasing the yaw rate. This must surely have been a most unwelcome surprise to the handling pilot who, under the circumstances, handled the situation as best he could. During the landing roll, both rudders are operating together until the final phase of rollout when the upper rudder can then be seen to misalign with the lower one (again). Might it conceivably be that there might be a fault within the speed sensing system (rudder limiter) which caused this upset. In any event, don't castigate the pilot until such time as it can be proven that there wasn't a problem with the rudder system.