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Colgan 3407 - 10 years today

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  • #16
    Originally posted by Gabriel View Post
    ***3WE says that they were slowing down too quickly and how on Earth they did not add thrust to correct that***
    No, I do not say that.

    They leveled and dirtied up the plane and it slowed down quickly...(not too quickly).

    Quickly enough that some sleep deprived, allegedly flirtatious, pilots did not seem to notice...and went on to get a stall warning...I would expect that leveling AND dropping flaps AND dropping gear AND flattening the props, would definitely call for an airspeed check and almost definitely call for some more power...

    Your discussion that maybe they were somewhat aware of their airspeed as opposed to totally unaware (but shocked by the unexpected stick shaker): Plausible.

    It is also consistent with your plausible theory of the tail stall...(Which Evan disagrees with and which I think is slightly less likely than tired and inattention to speed).
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    • #17
      Originally posted by 3WE View Post
      Indeed, it was deliberate and incorrect and I want to think I would not do that. But don't forget your favorite phrase "startle factor" and your love of frequent recurrent, type-specific instant-memory-procedure regurgitation training...I can see her behavior as a result of repeated loss-of-control training. .
      Remember, I'm the one here who isn't blaming either one of them. I think the blame rests on poor training, lack of experience and lack of rest. I think this was the result of mental confusion brought on by type unfamiliarity and insufficient practice on approach-to-stall, and thus a flawed instinctive reaction. I think the F/O might have retracted flaps because the onset of stickshaker appeared to be tied to flap extension. I also think she might not have had a full grasp of the role and aerodynamics of flaps. But even if that is true, I don't blame her. She didn't put herself in the cockpit, nor did he. What I find so frightening about this one is that a major US- branded airline put them there (as was the case with the 'happy-feet' F/O of AA587). The ONLY way to defend yourself against this kind of end is to make smart choices about whom you trust. We need airlines that we can trust to maintain the highest standard in vetting, training, preparing and looking after their pilots. Including anything they are allowed to put their brand on.

      Comment


      • #18
        Originally posted by 3WE View Post
        Gabieee also likes to point out that less nose-up input by the hard-over pilots would have given them an upright and theoretically airborne aircraft.
        Technically it was possible. It actually requires a reduction of AoA rather than just "less nose-up input". And an increase of speed because if you just reduce the AoA and don't increase the speed, down you go. Asymmetric thrust to reduce the effect of the rudder would have helped a lot too.

        Now, humanly, it was almost impossible. Nobody knew about the crossover speed at that time. It took a second fatal crash (USAir Flight 427 at Pittsburgh) and then an incident (Eastwind Flight 517 at Trenton) for the NTSB to figure it out, and only then the procedures to recover were developed.

        Mr Magenta Teacher talks about this, and how if you have the ailerons fully rolled in one direction and when you pull up the airplane rolls in the opposite direction and when you push down it rolls in the intended direction, that's a symptom of a rudder hard over. That's a funny part of his presentation, when he takes the model plane with one hand and rolls it one way and the other in coordination whith his other hand doing pull-up and push-down mimics.

        The only reason why I said "almost" is because there is one chance, one way, that they could have figured it out. The hard over and cross-over issues were not know, but it was very well known that roll authority and controllability degrade with increasing AoA and slower speeds and improve by reducing the AoA and increasing the speed. So whenever you have roll issues, reducing the AoA and increasing the speed is a good idea.

        --- 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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        • #19
          Originally posted by Gabriel View Post
          I still think (in contrast with the NTSB that says it is unlikely) that an attempt to recover a non-existent tail stall (and wrongly executed) is the best explanation. We will never know for sure one way or another, but here is way I think that way:

          Two things:
          1) One thing I didn't see in what you wrote: wouldn't there have been an automated voice saying "stall, stall" through much of this event? If so, one thing that should be considered is whether that should have prompted the pilots to know the wing had stalled (or was about to). Presumably the stall warning would not activate in the event of a tail stall? On the other hand, maybe the voice was saying "stall, stall" and what the pilot(s) heard was "tail stall, tail stall".

          2) Here's the thing I don't get the most: with one exception that I'm aware of, adding power is beneficial when you think a stall is taking place. Especially when the engines are at a low power setting that normally would not be enough to keep the plane airborne! The exception being planes with engines under the wings that have a nose-up pitch tendency at high power settings... but these people were not flying a plane like that, and probably hadn't in the past (so can't say they reverted to old learned behavior).
          Be alert! America needs more lerts.

          Eric Law

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          • #20
            Originally posted by elaw View Post
            Two things:
            1) One thing I didn't see in what you wrote: wouldn't there have been an automated voice saying "stall, stall" through much of this event? If so, one thing that should be considered is whether that should have prompted the pilots to know the wing had stalled (or was about to). Presumably the stall warning would not activate in the event of a tail stall? On the other hand, maybe the voice was saying "stall, stall" and what the pilot(s) heard was "tail stall, tail stall".
            No. The stall warning in the Q-400 (and in the majority of the transport category planes) is the stick shaker, which is what triggered the reaction of the pilot (a fraction of a second after its activation) and remained shaking all the way to the crash (because the pilot reaction was to pull back and keeping pull back, which of course is the opposite to what you need to do to stop make the stickshaker stop.
            Go to YouTube and search for the NTSB's animation of this accident.

            2) Here's the thing I don't get the most: with one exception that I'm aware of, adding power is beneficial when you think a stall is taking place. Especially when the engines are at a low power setting that normally would not be enough to keep the plane airborne! The exception being planes with engines under the wings that have a nose-up pitch tendency at high power settings... but these people were not flying a plane like that, and probably hadn't in the past (so can't say they reverted to old learned behavior).
            And what is what you don't get?
            The pilot did add power. But the stall is a matter of angle of attack. Yes, planes with the engines above the center of gravity will product a nose-down pitching moment when you add power and hence tend to reduce the AoA. But pulling back on the yoke to the stop (as they did) will do the opposite and win. The pitch effect by the power is a secondary side effect, The elevator is DESIGNED TO change the AoA, and hence it is much more powerful and effective than the engines at doing so.

            --- 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 ---

            Comment


            • #21
              Originally posted by Gabriel View Post
              No. The stall warning in the Q-400 (and in the majority of the transport category planes) is the stick shaker, which is what triggered the reaction of the pilot (a fraction of a second after its activation) and remained shaking all the way to the crash.
              The stickshaker actually silenced for about a second during the upset. The yoke was not kept at the backstop either. At some moments, while reacting to roll, it was returned close to neutral. As I said long ago, while the initial pull and subsequent pulls seem deliberate reactions to the stick pusher activations, I think, when trying to control roll and yaw, he might have been mentally unaware of his column inputs. And it seems pretty likely that he wasn't watching the attitude indicator.

              Comment


              • #22
                Originally posted by Gabriel View Post
                And what is what you don't get?
                The pilot did add power. But the stall is a matter of angle of attack. Yes, planes with the engines above the center of gravity will product a nose-down pitching moment when you add power and hence tend to reduce the AoA. But pulling back on the yoke to the stop (as they did) will do the opposite and win. The pitch effect by the power is a secondary side effect, The elevator is DESIGNED TO change the AoA, and hence it is much more powerful and effective than the engines at doing so.
                I just rewatched the NTSB animation and guess I wasn't paying enough attention the first time I looked at it. My recollection was that after the stick shaker activated, there was a delay before the power levers were moved, and when they were it was fairly slowly. But when I looked at it just now, it did appear the power was added very soon after the stick shaker went off, and pretty quickly.
                Be alert! America needs more lerts.

                Eric Law

                Comment


                • #23
                  Originally posted by Gabriel View Post
                  ***the stall is a matter of angle of attack***
                  Hair splitting- but I still disagree: firewalling the throttles but not adjusting the pitch is an ok response to a stall warning.

                  It’s the relentless pull up in response to an actual stall that I object to...

                  Did it in 172 school and don’t object to airline pilots practicing it... just so they know that you are totally fixated on AOA and that technically you are correct and that they will at least consider some nose down input if it looks like you’ve really stalked.
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                  • #24
                    Originally posted by 3WE View Post
                    Hair splitting- but I still disagree: firewalling the throttles but not adjusting the pitch is an ok response to a stall warning.
                    Well, that depends on what is, for you, "not adjusting the pitch".

                    We discussed this ad-nauseum in the Stall thread. It went more or less like this:

                    - If by "not adjusting the pitch" you mean "leaving the yoke in its current position", you are wrong. And this little dot is a period. It really doesn't matter a lot whether you agree or not. You may very well disagree with the globe Earth, the existence of gravity, and that we went to the Moon.
                    - If by "not adjusting the pitch" you mean "keeping the current pitch attitude", then in many (but not all) of the cases that is ok. In the case of the Colgan accident, it is ok. Note, however, that if you are going to increase speed, the pitch will tend to increase by itself, so to keep the current pitch attitude you will to actively move the yoke forward of its current position. That is, you will be reducing the angle of attack. And that's why it works. Do you know why? Because stall is a matter of angle of attack and you will not recover from a stall or from an approach to stall without reducing the angle. And this little dot is another period.

                    If you have further doubts, please consult https://forums.jetphotos.com/showthread.php?50119-Stall.

                    --- 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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                    • #25
                      Originally posted by Gabriel
                      Blah, Blah, Blah
                      No acknowledgement of stall warning vs true full stall.

                      Yeah, 16 degree AOA = stall (on many many types) and sometimes you gotta drop the nose a bit...and still find Air France “incomprehensible”. (Little dot there)
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                      • #26
                        Originally posted by 3WE View Post
                        No acknowledgement of stall warning vs true full stall.
                        Acknowledgment:
                        - In a stall warning situation the angle of attack is too high (1). Any recovery needs to involve reducing the angle of attack or it doesn't make sense.
                        - In a true full stall situation the angle of attack is too high (2). Any recovery needs to involve reducing the angle of attack or it doesn't make sense. (3)





                        (1) At least dangerously close to the critical AoA, if not at or beyond the critical AoA.
                        (2) Beyond the critical AoA.
                        (3) A true full stall situation is a subset of the stall warning situations.


                        Happy?

                        --- 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 ---

                        Comment


                        • #27
                          Originally posted by Gabriel View Post
                          Acknowledgment:
                          - In a stall warning situation the angle of attack is too high (1). Any recovery needs to involve reducing the angle of attack or it doesn't make sense.
                          - In a true full stall situation the angle of attack is too high (2). Any recovery needs to involve reducing the angle of attack or it doesn't make sense. (3)





                          (1) At least dangerously close to the critical AoA, if not at or beyond the critical AoA.
                          (2) Beyond the critical AoA.
                          (3) A true full stall situation is a subset of the stall warning situations.


                          Happy?
                          No.

                          Adding full power and closely monitoring performance is an appropriate procedure.
                          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                          Comment


                          • #28
                            Originally posted by 3WE View Post
                            No.

                            Adding full power and closely monitoring performance is an appropriate procedure.
                            Does "closely monitoring performance" involves acting accordingly if the performance doesn't match expectation? (or even better, acting proactively to enforce a performance that matches the expectation).

                            Because, again, you are flying at 5 degrees nose-up pitch when the stickshaker activates. If you just firewall the throttles and just passively monitor the performance you very soon will monitor as the the pitch goes to 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 degrees. You've said:

                            firewalling the throttles but not adjusting the pitch is an ok response to a stall warning.
                            But, as you can see you are adjusting the pitch by inaction.

                            --- 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 ---

                            Comment


                            • #29
                              Originally posted by Gabriel View Post
                              But, as you can see you are adjusting the pitch by inaction.
                              I’m not adjusting pitch. It’s at 25 degrees nose up.

                              My powerful, trim neutral tail engine turbofan is accelerating away from the incipient stall.

                              I know my AOA got a bit high, but it stayed below 16 degrees and I’m not pulling up relentlessly and if I encounter a freak, severe speed loss shear (or some other mechanism causes a full stall) I will consider a nose down input.

                              As I gain speed, there may be nose down inputs to maintain pitch as I monitor things. Maybe I’m even on autopilot and in an Airbussy-style FBW plane.

                              Full power...fly away at max climb...no altitude loss...not an super genius skill.
                              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                              • #30
                                Originally posted by 3WE View Post
                                As I gain speed, there will be nose down inputs to maintain pitch as I monitor things.
                                Fixed and deal.

                                --- 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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