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AeroUnion 6R-302 Final Report

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  • AeroUnion 6R-302 Final Report

    But I've been pushing down the whole time...

    Oh, right... pitch trim...

    PF: 16,754 hours

    http://avherald.com/h?article=42a18e75&opt=0

  • #2
    Definitely sounds like the pilot(s) are #1 to blame, but a strong #2 is the system that automatically applied full thrust on the engines which, without pilot intervention (in the form of adjusting the trim), is pretty much guaranteed to cause a crash.
    Be alert! America needs more lerts.

    Eric Law

    Comment


    • #3
      [QUOTE=elaw;668629 #2 is the system that automatically applied full thrust on the engines which, without pilot intervention (in the form of adjusting the trim), is pretty much guaranteed to cause a crash.[/QUOTE]



      There is a system that does that on the Airbus? ATL Please.

      Comment


      • #4
        Originally posted by elaw View Post
        Definitely sounds like the pilot(s) are #1 to blame, but a strong #2 is the system that automatically applied full thrust on the engines which, without pilot intervention (in the form of adjusting the trim), is pretty much guaranteed to cause a crash.
        Seriously? You give "strong #2" blame to a system that adds TOGA escape thrust well after a SPEED SPEED aural warning hasn't sufficed and then only after the AoA has reached a point just below stall? The fact is, it works perfectly well if the pilots are flying the plane, and flying the plane includes pitch trim.

        I give a strong #2 to pilots not well-trained in BLENDED automation, as in this case where autopilot was in use but thrust was being controlled manually... until it wasn't and the system had to step in.

        We've seen a lot of crashes and incidents that occurred in these blended states.

        Comment


        • #5
          Originally posted by BoeingBobby View Post
          There is a system that does that on the Airbus? ATL Please.
          It's not quite that simple, but, more to the point, this is the first I hear of the A300 (an early 300B rather than a 306 to boot) having alpha floor. I'm wondering if there is a Spanglish issue.

          Comment


          • #6
            Originally posted by Evan View Post
            The fact is, it works perfectly well if the pilots are flying the plane, and flying the plane includes pitch trim.
            If the pilots were flying the plane properly, the alpha floor function (if it in fact exists, see above) would not have engaged.

            To me there's a huge difference between an alpha floor system that works as described in the report, and a TOGA button. It's implicit that the function of the TOGA button is only to set engine thrust... the pilots are expected to manage everything else, including pitch trim. An alpha floor function to me is a very different beast... if it comes into play, it's presumably because the pilot(s) aren't paying attention. And in that case, having it do something that's intended to keep the plane from crashing but the thing it's doing also will *cause* the plane to crash if the pilots don't intervene (which would require them to be paying attention), is kind of illogical.
            Be alert! America needs more lerts.

            Eric Law

            Comment


            • #7
              Originally posted by elaw View Post
              ...but the thing it's doing also will *cause* the plane to crash if the pilots don't intervene (which would require them to be paying attention), is kind of illogical.
              Is it? The pilots are there to a) fly the plane and b) monitor the automation. In this case, under blended automation, they need to be doing both. If they don't, it crashes, regardless of whether it is an Airbus or a Boeing or a really deluxe Cessna.

              In my opinion, paying attention to the flight surface controls is always logical. And of course... airspeed...

              BTW: The onset of TOGA thrust does not cause the plane to pitch-up uncontrollably, but it requires some control compensation from the pilots. The pilots DID add forward column here to compensate, but this was ineffective with the pitch trim still at 10+ degrees. Inputs to both are needed. Previous incidents have already warned us that even pilots with some tall hours are not getting well-trained on the importance of pitch trim in upset recovery situations. Apparently, this is still being neglected.

              Comment


              • #8
                I agree with most of what you say but the feature the report mentions is there precisely to deal with the possibility that the pilots may not be doing their jobs. It is advertised as a "backup system" that will save the plane from a potentially fatal situation, if the individual(s) flying do not perform as they are supposed to. The fact that this "backup system" will in fact cause the plane to crash if the pilots do not perform as they are supposed to for just a few moments longer, maybe needs a little more emphasis.
                Be alert! America needs more lerts.

                Eric Law

                Comment


                • #9
                  Originally posted by elaw View Post
                  The fact that this "backup system" will in fact cause the plane to crash if the pilots do not perform as they are supposed to for just a few moments longer, maybe needs a little more emphasis.
                  Yes, it does, in pilot training. The fact that, if pilots do not do what they are supposed to be doing, the plane will crash, needs more emphasis. Particularly if the people being trained are morons.

                  Alpha floor is there to add thrust if the [potential morons] simply fail to manage airspeed even after the low speed protection has already [gently reminded] them (twice). There is no hard AoA protection on the A300, so the airplane, in a last-ditch-effort to save itself from the humans, adds TOGA thrust TRUSTING that this will get the attention of the pilots, who will then do their part with the flight control surfaces. In this last aspect, the airplane is a little naive. Newer Airbus jets (A320 and onward) seem to have a better idea of how much you can trust [certain pilots].

                  I suppose they could have automated the trim to be taken out with Alpha Floor activation. I'm sure they had a really good reason not to. Anyway, as it turned out, they redesigned their newer aircraft with far less margin for pilot error. And that made [certain pilots] bitter and deeply affronted.

                  Comment


                  • #10
                    And hopefully, by now, after so many incidents, most pilots have learned that if pitch commands alone are ineffectual, to INSTINCTIVELY adjust pitch trim.

                    Comment


                    • #11
                      Amazingly, I tend to agree with Evan here.

                      Almost identical incidents, in which sheer luck was a main factor for these incidents not being accidents, happened in Boeing 737s at least twice, after a Go Around was initiated almost simultaneously with the stickshaker, by either pushing the TOGA buttons or manually adding thrust, after the plane had been approaching in a decaying speed condition. The truth is, the only ways to avoid this behavior would be to have an active angle-of attack protection that includes automatically adjusting the trim (since the elevator alone would not be enough regardless of whether the one pushing down is Joe or Otto) or to redesign the airplane completely in a way that places the engines' line-of-thrust closer to the CG, because nothing will change the facts that the slower the plane, the less effective the elevator and the stronger the thrust / pitching moment coupling.

                      If the pilots are not flying the plane, or are flying the plane with gross incompetence, the plane will crash, eventually. Even the ones mentioned by Evan that put less reliance on the pilot, as the A320 or A330, will crash. Or look at AF 296 and AF 447.

                      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                      --- Defend what you say with arguments, not by imposing your credentials ---

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