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Dash 8 near crash when recovers from stall at 75ft

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  • Dash 8 near crash when recovers from stall at 75ft

    A Dash 8 is in a visual approach, in a descending turn downwind to base, when it loses speed and stalls. The captain (PF) freezes, the FO takes over at 250ft and lowers the nose to recover from the stall and then pulls up 2.7G, finally managing to arrest the descent and climb to safety after reaching as low as 75 ft AGL.

    And this is not most amazing part!

    This is a masterpiece of journalism by Simon Hradecky and his The Aviation Herald that deserves that you go and read the story from the source.

    http://avherald.com/h?article=487ffab8&opt=0

    --- 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 ---

  • #2
    Originally posted by Gabriel View Post
    This is a masterpiece of journalism by Simon Hradecky and his The Aviation Herald that deserves that you go and read the story from the source.

    http://avherald.com/h?article=487ffab8&opt=0
    Seconded!

    It's nice to see there's still at least one investigative journalist out there doing good work for the right reasons.
    Be alert! America needs more lerts.

    Eric Law

    Comment


    • #3
      Slowing for landing.
      Adding draggy stuff.
      Making a turn at low altitude.
      Gusty, turbulent conditions.

      Watch airspeed, be ready on the power and willing to give small, nose down inputs.

      Definitely do not sit there mindlessly and complacently driving the plane down to the same landing you've done a thousand times before with a total mental block to where you freeze and can't address a stall warning...

      But, WTF do I know, that's just a general, fundamental, cowboy checklist, and absolutely nothing specific to do with a Dash-8--236A (or was it a 233B?)
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #4
        A few particularly remarkable things...

        As soon as the stickshaker starts, the captain applies full power and pitches 10° nose-up. Wasn't that the standard stall recovery procedure "by the book" back then? The plane still stalls. Here we go with the "power (alone) to recover a proximity to stall".

        So, the plane fully stalls and consequently starts to descent. The plane is as low as 250ft AGL and descending in a way that cannot be arrested. What does the FO does? LOWER THE NOSE!!! Even when ground contact was evidently of concern, the FO had the clarity of mind to react as required. Even with the ground so close and coming to you so fast, the descent could have not been arrested if not by reducing the AoA first.

        And not only that, before doing the above, the FO had to decide that the captain was not able to perform his duties anymore and take over. That´s never an easy decision.

        The AvHerald doesn't mention the experience of the crew, but I have a feeling (I cannot say that I suspect or guess even) that we'll find a fresh FO, the hypothesis being that, at a point, much experience in airline operations take the pilots away from the basics learnt in the primary instruction.

        --- 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


        • #5
          Originally posted by Gabriel View Post
          As soon as the stickshaker starts, the captain applies full power and pitches 10° nose-up. Wasn't that the standard stall recovery procedure "by the book" back then?
          An excellent procedure to minimize the loss of precious altitude (and they were quite low!) that works the vast majority of the time...

          It's just a good idea to not blindly follow procedure and instead know all that fundamental background cowboy "BS" about AOA, any attitude and airspeed and lowering the nose a bit, just like in your first hour of flight training.
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • #6
            Originally posted by 3WE View Post
            An excellent procedure to minimize the loss of precious altitude (and they were quite low!) that works the vast majority of the time...

            It's just a good idea to not blindly follow procedure and instead know all that fundamental background cowboy "BS" about AOA, any attitude and airspeed and lowering the nose a bit, just like in your first hour of flight training.
            The stick shaker starts. I give you one second to react and another second to make it stop. If it doesn't, whatever you are doing is not working.

            I mentioned this back then (stall rant thread), but what the old procedure didn't mention is that, in a low altitude approach to stall scenario (and as long as the plane is not actually stalled), it requires PUSHING DOWN after applying full power to prevent the nose from raising beyond 10°. It is that pushing down (i.e. reducing AoA), and not the full power, what gets you away from the stall.

            Pushing down first, if only barely enough to make the stickshaker stop, and then (which is almost simultaneously) adding full power, will be more effective to minimize altitude loss. Because stall (full or proximity) is a matter of too much AoA, reduce AoA must come as the first action. Then (which can be a split second later) you care about power, levelling the wings, etc...

            --- 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


            • #7
              Originally posted by Gabriel View Post
              The AvHerald doesn't mention the experience of the crew, but I have a feeling (I cannot say that I suspect or guess even) that we'll find a fresh FO, the hypothesis being that, at a point, much experience in airline operations take the pilots away from the basics learnt in the primary instruction.
              ...and over-familiarity...good training in stall avoidance and nailing airspeed means almost never ever ever ever ever ever ever ever (almost) see a stall warning after thousands upon thousands upon thousands of landings...
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

              Comment


              • #8
                Originally posted by Gabriel View Post
                The stick shaker starts. I give you one second to react and another second to make it stop. If it doesn't, whatever you are doing is not working.

                I mentioned this back then (stall rant thread), but what the old procedure didn't mention is that, in a low altitude approach to stall scenario (and as long as the plane is not actually stalled), it requires PUSHING DOWN after applying full power to prevent the nose from raising beyond 10°. It is that pushing down (i.e. reducing AoA), and not the full power, what gets you away from the stall.

                Pushing down first, if only barely enough to make the stickshaker stop, and then (which is almost simultaneously) adding full power, will be more effective to minimize altitude loss. Because stall (full or proximity) is a matter of too much AoA, reduce AoA must come as the first action. Then (which can be a split second later) you care about power, levelling the wings, etc...
                ...or at least spend 5 min at every other recurrent training, right after the V-1 engine cut, to discuss full stalls, recognizing them, and all of the basic, fundamental, cowboy BS along with mentioning some of the near-total disasters that have almost occurred and they didn't died and the actual total disasters that actually occurred and they did died...

                ...just to drive home that on rare occasions, this stuff is a matter of life and death.
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • #9
                  Originally posted by 3WE View Post
                  ...and over-familiarity...good training in stall avoidance and nailing airspeed means almost never ever ever ever ever ever ever ever (almost) see a stall warning after thousands upon thousands upon thousands of landings...
                  Concur, but this was a tricky non-straight visual approach in tricky terrain, tricky darkness and tricky meteorological conditions (low ceilings, low vis, high gusting winds) which increase the chances of "shit happens".

                  So, I fully endorse the above, but be prepared for that (almost).

                  --- 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


                  • #10
                    Originally posted by Gabriel View Post
                    I mentioned this back then (stall rant thread), but what the old procedure didn't mention is that, in a low altitude approach to stall scenario (and as long as the plane is not actually stalled), it requires PUSHING DOWN after applying full power to prevent the nose from raising beyond 10°. It is that pushing down (i.e. reducing AoA), and not the full power, what gets you away from the stall.
                    Really, even for a t-prop? I thought the old procedure was to first add full power and to maintain (manage) pitch so as not to lose altitude but not to allow it to increase (maintaining forward pressure, but not pushing down).

                    Comment


                    • #11
                      I think the best answer is "it depends on the aircraft". I think in most aircraft, when power is increased the AoA tends to increase if you don't move or retrim the elevator.

                      Of course an AoA-increase tendency will only make a stall worse *if the pilot does not correct for it*. But as we've seen pilots sometimes don't correct for it. Probably in most cases due to the poor skills / lack of SA / lack of alertness that got them into a stall in the first place.
                      Be alert! America needs more lerts.

                      Eric Law

                      Comment


                      • #12
                        Originally posted by Evan View Post
                        Really, even for a t-prop? I thought the old procedure was to first add full power and to maintain (manage) pitch so as not to lose altitude but not to allow it to increase (maintaining forward pressure, but not pushing down).
                        Yes, really. And what you say makes no sense. In a low altitude stall proximity scenario, "applying forward pressure to avoid that the latitude increases" after applying full power means reducing pitch and AoA. First of all, that very much is "pushing down" so your "not pushing down" is self-contradictory. Second, you can do better than that. You can let the nose go up 10, 15, 20 degrees AFTER the stickshaker stopped.

                        I already mentioned this several times, but REDUCING THE AOA (together with adding thrust) is conductive to, simultaneously, increase airspeed, improve controllability, increase climb rate, climb gradient, and pitch. It might seem paradoxical that you will increase climb rate, climb gradient and pitch by "pushing down" (or applying forward pressure, if you will), but that's what happens if you manage it correctly (which includes not pushing too much down).

                        --- 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


                        • #13
                          Originally posted by Gabriel View Post
                          Yes, really. And what you say makes no sense. In a low altitude stall proximity scenario, "applying forward pressure to avoid that the latitude increases" after applying full power means reducing pitch and AoA. First of all, that very much is "pushing down" so your "not pushing down" is self-contradictory.
                          FIrst of all, we are talking about OLD procedure and secondly we are talking about stickshaker, not stall, in a t-prop. I'm pretty sure, in a t-prop, the old SOP was to get on full power while PRESERVING a positive pitch with only forward PRESSURE, so not letting the pitch increase as the airspeed does, but also NOT PUSHING DOWN to sacrifice altitude, this being an aircraft that is not yet stalled and without underslung thrust or thrust lag issues. The other way I read it was to MANAGE pitch, meaning to preserve altitude—not sink—but only once the stall warning has been extinguished. The OLD mentality was to preserve altitude and climb out as soon as possible. The new mentality favors giving up altitude to assure stall avoidance. RIght?

                          Would that not have worked here, before the 10° pitch increase and the subsequent stall? If you are not yet stalled in a Dash-8 and you don't let the pitch increase above stickshaker (and hopefully lowering it a tick), shouldn't you be able to power out of the situation?

                          Comment


                          • #14
                            Old mentality: Engines are big and powerful and using them to power out of an incipient stall is a great way to have no altitude loss.

                            New mentality: Pulling up relentlessly while going slow is a good way to stall a plane.
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                            Comment


                            • #15
                              Originally posted by Evan View Post
                              FIrst of all, we are talking about OLD procedure and secondly we are talking about stickshaker, not stall
                              Yes Evan, I have stopped answering because I am tired of repeating the same thing, but I will do it once more:

                              Stick shaker: too much AoA
                              Stall: too much AoA (even more than before).
                              Recovery: Reduce AoA.

                              There is no difference in the recovery procedure because:
                              Both of them are too much AoA and hence both of them require an AoA reduction to recover.
                              The zone between the stickshaker onset and the full stall is very unsafe and of vary bad performance. There is no gain not reducing the AoA to silence the stickshaker.
                              You cannot tell the difference anyway, not until it is too late. And you cannot sense if the situation is worsening or improving until you are falling out of the sky or the stickshaker stopped.

                              I could care not less if we are talking new procedure, old procedure, stickshaker, approach to stall, during take off, cruise, landing, power on, power off, accelerated, or whatever.

                              The problem is too much AoA.
                              Any procedure that doesn't involve reduction of AoA until all any signs of stall stop makes no sense whatsoever.

                              --- 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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