PRB
December 17th, 2009, 15:50
When I first flew the A-321 in FSX, I didn't understand why the rudder pedals seemed to have no effect of the plane. It was very difficult to control this way, and almost impossible to land. Then, after some questions here and some Googling, I found the culprit. Above the pilot, the FLT CTRL panel has a push button labeled SEC1 which, if turned off, allows the rudders to work. There are two other flight control related push buttons on that panel, and above the co-pilot's head there is another FLT CTRL panel, with a SEC2 and a SEC3 push button. I haven't tried these yet. I do know that turning off SEC1 above the pilot “enables” the rudders.
I'm betting this has something to do with an electronic “fly-by wire” FCS, but this can't be how the real airplane works. It's as though turning off SEC1 simulates the deactivation of the automatic coordination of the control surfaces, and places it in a manual mode of some sort. But even in “auto” mode, or whatever it's called, the pilot should be able to turn the airplane in a coordinated manner, even if the FCS does it for him. In the FSX A-321, leaving that system “on” appears to simply disable the rudder completely.
The other thing I'm wondering is if this system was added to the Airbus fleet after the accident of November 12, 2001, in which an American Airlines A-300 crashed over New York City after the tail broke off, apparently as a result of the co-pilot “walking” the rudder pedals too aggressively while trying to keep the ship under control after flying through some 747 wake turbulence. This was an “interesting” (if that's the right word) accident because “common sense” would tell us “office pilots” that the rudder should stay on, even if the co-pilot stomps on the pedals a couple of times. But as is so often the case, “common sense” is apparently wrong, and this issue is not limited to Airbusses. The issue, I'm told, wasn't simply that the pilot “pushed too hard” on the pedals, but it was the repeated back and forth with the pedals at maximum deflection, which set up an oscillation of the tail that over stressed it. I'm also told that the KC-135 has a warning about doing that very thing, and for the same reason. This I don't know, and maybe some KC-135 gurus can confirm or deny this.
I'm betting this has something to do with an electronic “fly-by wire” FCS, but this can't be how the real airplane works. It's as though turning off SEC1 simulates the deactivation of the automatic coordination of the control surfaces, and places it in a manual mode of some sort. But even in “auto” mode, or whatever it's called, the pilot should be able to turn the airplane in a coordinated manner, even if the FCS does it for him. In the FSX A-321, leaving that system “on” appears to simply disable the rudder completely.
The other thing I'm wondering is if this system was added to the Airbus fleet after the accident of November 12, 2001, in which an American Airlines A-300 crashed over New York City after the tail broke off, apparently as a result of the co-pilot “walking” the rudder pedals too aggressively while trying to keep the ship under control after flying through some 747 wake turbulence. This was an “interesting” (if that's the right word) accident because “common sense” would tell us “office pilots” that the rudder should stay on, even if the co-pilot stomps on the pedals a couple of times. But as is so often the case, “common sense” is apparently wrong, and this issue is not limited to Airbusses. The issue, I'm told, wasn't simply that the pilot “pushed too hard” on the pedals, but it was the repeated back and forth with the pedals at maximum deflection, which set up an oscillation of the tail that over stressed it. I'm also told that the KC-135 has a warning about doing that very thing, and for the same reason. This I don't know, and maybe some KC-135 gurus can confirm or deny this.