Wino Thanks for the pedal momentum info. If you are busy with a wake encounter in a climbing 25º bank with accelerations on all three axes it must be easy to pass through the zero position the second and third time.
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Wino Airbus said on the witness stand that the rudder load limiter could be overpowered. …….…. rudder gets exponentially more sensitive the faster you go, AND it is possible to have no limits. …..
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I am curious as to exactly what Airbus said at the hearing about their rudder system. Did they say that the rudder PEDAL limiter could be overpowered, or did they say the RUDDER limiter could be overpowered, or both?
The reason for asking is that so far as I can see, although the AA587 Reconstruction video (Rv) shows that the PEDAL limits were exceeded, it also shows that the RUDDER limits were NOT exceeded.
Here is a frame from the Rv during the second wake encounter. Red lines indicate the limits for the pedals and the rudder. The pedal limit has been overpowered, but the rudder limit has NOT. In fact, so far as I can see, in neither the filtered nor the estimated un-filtered RUDDER positions, in either the Rv or the FDR traces, does the RUDDER go outside the limits. So it might be of interest to look and see exactly what Airbus said according to the NTST hearing transcript (I don‘t have a copy)?
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Wino …. nor could Captain States have known that he was banging off the stops. …
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The witness captain said that the reason that he became aware of aggressive use of the rudder was that he had the habit of keeping his feet on the pedals when he was PNF. How common is this method of checking? Could other Captains have missed something?
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Wino It looks like they were in the turn when they hit the first wake which served to level the aircraft. … They were rolling back into the turn when they hit the second wake further rolling the aircraft in the direction of the turn. ….
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Just being Picky, but I don’t think either of these statements are quite right.
The FDR shows the a/c was climbing with no roll and on a constant heading when it encountered the first wake, though it started to turn left soon afterwards.
The FDR also shows that the a/c had been in a climbing left-hand turn for at least 10 seconds and had changed heading by about 15 degrees when it encountered the second wake, .The (filtered) bank angle decreased as soon at the a/c hit the wake.
So the a/c hit the first wake wings level, but it was in a climbing 25º left-hand bank when it hit the second wake.
Maybe just details, but also, maybe, it might turn out to be a significant difference.