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Dash 8 near crash when recovers from stall at 75ft

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  • #31
    Ok, I read it. The pitch moment/AoA factor is technically interesting but also momentary and I have to ask how significant a factor that is in contributing to a real-world fully developed stall. Is it really enough to silence stickshaker more than momentarilly or even at all?

    Also, does "the pitching moment of the the thrust may overpower the elevator" apply to the Dash 8 or any t-prop where the tractor propulsion is practically in-line with the wing?

    But mainly this:
    So, with this theoretical exception for which I have never seen a case, we must say that ELEVATOR CONTROLS AOA (again, including trim). Not pitch and power (which can affect AoA, but are not a direct means to control it).
    Whaat? If pitch and power are not a direct means to control AoA, what is? In wings-level flight, what does elevator control if not pitch? Is elevator not the main means of controlling the pitch axis? Have I had that wrong all along?

    Lets rewind. You wrote:
    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"
    To which I contended that, while not the optimized modern procedure, at proximity to stall (onset of stickshaker) in this aircraft (a Dash 8 ), when not pitching up 10° or even 1°, it should be possible to recover with power alone. I also added that this procedure (power first, then manage pitch) would involve a forward pressure to prevent pitching up (NOT hands-off) and ideally reduce pitch slightly but not so much that results in a significant loss of altitude.

    Since power=airspeed and airspeed lowers AoA if elevator (forward pressure) maintains current pitch, I can't find in your reply why this isn't true.

    EX: a Dash 8 is flying at 6° ANU and speed gradually falls off, thus increasing AoA to stickshaker (approach-to-stall margin below critical angle). Pilot first firewalls throttle, then applies yoke pressure as needed to maintain 6° ANU. Not the safest course of action but shouldn't that work?

    2ND EX: Same as the above but pilot applies forward yoke to maintain 4° pitch.

    Both with no configuration changes.

    In the end you are reaching the same conclusion I did when I read this, which is that the pilot probably overreacted in the full-stall recovery and put the aircraft much closer to terra firma than he should have. I agree that this is better than the opposite reaction (not enough) that would have put it squarely on terra firma.

    But isn't the problem in both cases flawed procedure? Why must we choose between these extremes, between stall and CFIT?

    And, of course, the real issue here is that the PF did not use any procedure to lower the AoA at stall warning, but rather let the airplane pitch up into a stall.

    Comment


    • #32
      Originally posted by guamainiac View Post
      Now gents, I wonder just how many details a fellow can process between 75' and the ground?
      I think I can handle five:

      1) If you are going slow...

      2) If you are pulling up a bit...(trimming up a bit (especially with your thumb switch and not a big tactile, visual wheel), letting Otto maintain altitude)

      3) If a warning thingie makes ugly noises and/or worse yet, you sense a sudden loss in lift...

      4) Power up and shove the nose over slightly (I don't give a rat what order, Gabe, in fact I lump it into "simultaneously")...

      5) Reevaluate and adjust attitude as appropriate...

      (Just basic cowboy stick and rudder stuff)
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #33
        Originally posted by Evan View Post
        Ok, I read it. The pitch moment/AoA factor is technically interesting but also momentary and I have to ask how significant a factor that is in contributing to a real-world fully developed stall. Is it really enough to silence stickshaker more than momentarilly or even at all?

        Also, does "the pitching moment of the the thrust may overpower the elevator" apply to the Dash 8 or any t-prop where the tractor propulsion is practically in-line with the wing?

        But mainly this:
        Whaat? If pitch and power are not a direct means to control AoA, what is? In wings-level flight, what does elevator control if not pitch? Is elevator not the main means of controlling the pitch axis? Have I had that wrong all along?

        Lets rewind. You wrote:
        To which I contended that, while not the optimized modern procedure, at proximity to stall (onset of stickshaker) in this aircraft (a Dash 8 ), when not pitching up 10° or even 1°, it should be possible to recover with power alone. I also added that this procedure (power first, then manage pitch) would involve a forward pressure to prevent pitching up (NOT hands-off) and ideally reduce pitch slightly but not so much that results in a significant loss of altitude.

        Since power=airspeed and airspeed lowers AoA if elevator (forward pressure) maintains current pitch, I can't find in your reply why this isn't true.

        EX: a Dash 8 is flying at 6° ANU and speed gradually falls off, thus increasing AoA to stickshaker (approach-to-stall margin below critical angle). Pilot first firewalls throttle, then applies yoke pressure as needed to maintain 6° ANU. Not the safest course of action but shouldn't that work?

        2ND EX: Same as the above but pilot applies forward yoke to maintain 4° pitch.

        Both with no configuration changes.

        In the end you are reaching the same conclusion I did when I read this, which is that the pilot probably overreacted in the full-stall recovery and put the aircraft much closer to terra firma than he should have. I agree that this is better than the opposite reaction (not enough) that would have put it squarely on terra firma.

        But isn't the problem in both cases flawed procedure? Why must we choose between these extremes, between stall and CFIT?

        And, of course, the real issue here is that the PF did not use any procedure to lower the AoA at stall warning, but rather let the airplane pitch up into a stall.
        You know...

        Some CRJ pilots seem to have an issue with this...

        Some Q-400 pilots seem to have an issue with this...

        Some A-300 pilots seem to have an issue with this...

        One Dash-8 pilot seems to have an issue with this...

        (Ask Gabe for a list of 10 more eye rollers).

        Maybe instead of splitting this out into multiple sub-procedures, it can be summarized and simplified into one procedure that works pretty damn good in Cessna 150's and A-380's. (See 5-step procedure above)

        THEN,

        MAYBE,

        LESS
        people will forget what to do.

        (I doubt we will ever achieve 100%, even if everyone adopts your screening and training suggestions)
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • #34
          Originally posted by 3WE View Post
          Maybe instead of splitting this out into multiple sub-procedures, it can be summarized and simplified into one procedure that works pretty damn good in Cessna 150's and A-380's.
          It really already is. They used to tell pilots to prioritize power and now they tell them to prioritize elevator. They used to tell pilots to prioritize altitude and now they tell them to prioritize AoA.

          Nowhere did it ever tell pilots to pull up relentlessly or not bring on power. That is where most of these accidents come from. Not so much wrong procedure as lack of procedure. The newer procedures have a greater margin of error but again, only if they are applied....

          Comment


          • #35
            Originally posted by Evan View Post
            Nowhere did it ever tell pilots to pull up relentlessly or not bring on power.
            Many procedures end with "climb" X-hundred feet straight ahead;" and in some cases reducing attitude was vehemently discouraged.

            I also know that in some cases, powering up while largely maintaining a climb attitude was trained with little or no mention of the old "any attitude and airspeed" mantra.

            I know that does not say "pull up relentlessly"

            However, climbing does require a pull up and it seems that some pilots supplied the relentless part (possibly due to a lack of training to reduce AOA ANU ETC.)
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

            Comment


            • #36
              Originally posted by Evan View Post
              Ok, I read it. The pitch rate/AoA factor is technically interesting but also momentary and I have to ask how significant a factor that is in contributing to a real-world fully developed stall. Is it really enough to silence stickshaker more than momentarilly or even at all?
              (slight fix above)

              Ok, let's neglect for a second the eventual pitching moment of the thrust and any pitching moment other than that of the lift of the wing and stabilizer and the "natural" pitching moment of the wing (due to it's camber). If you have enough power available to increase the speed, yes, this effect can be significant. And while it is correct that it is momentary, it can typically last a few dozens of second (about half a period of the long-period longitudinal oscillation mode, a.k.a. phugoid). This can buy a good bunch of time and altitude before its effect fades. This effect is the reason why you can "power out the stall" in the short term (hands off the yoke). When the airplane stops pitching up the effect disappears, the AoA returns to the original one and, even worse, the plane will start the second half of the phugoid, pitching down and increasing the AoA.

              Now, note that the above is caused by an increase of speed beyond the "trim" speed (that is what makes the plane pitch up). If you are in a 777 (underslung engines), the same excess thrust that will make the plane speed up will also make the plane pitch up. Who will win? Depends on too many factors.

              Also, does "the pitching moment of the the thrust may overpower the elevator" apply to the Dash 8 or any t-prop where the tractor propulsion is practically in-line with the wing?
              You are correct, I forgot to mention it. It was more aimed at the modern jets with the engines under the wings. Probably the engines of the Dash 8 are a bit above the CG, so the pitching moment will likely be nose-down (but tiny). That said, the vertical location of the engines is not the only factor. The longitudinal position also affects because the prop or jet at an AoA deflects the air from its original direction, so at positive AoA it makes an upwards force and at negative AoA it makes a downward force. That is destabilizing if the prop is ahead of the CG and stabilizing if it is aft. So I cannot answer with certainty but, in any event I don't expect any significant nose-up moment due to the thrust in the Dash 8.

              But mainly this:
              So, with this theoretical exception for which I have never seen a case, we must say that ELEVATOR CONTROLS AOA (again, including trim). Not pitch and power (which can affect AoA, but are not a direct means to control it).
              Whaat? If pitch and power are not a direct means to control AoA, what is? In wings-level flight, what does elevator control if not pitch? Is elevator not the main means of controlling the pitch axis? Have I had that wrong all along?
              Pitch axis is... an axis (perpendicular to the airplane's symmetry plane and passing through the CG).
              Pitch is an angle, the angle between the deck and the horizon.
              Pitch rate is an angular speed (the rate at which pitch changes).
              AoA is an angle, the angle between the deck and the relative wind.
              NONE OF THEM ARE CONTROLS.

              Yes, the elevator is the main mean to control all these things.
              So when I say "reduce AoA at least as needed to silence the stickshaker", I really mean "use the elevator to reduce the AoA at least..."

              The important thing is that you have to control AoA, not pitch, and it is NOT THE SAME, as demonstrated by the part that I highlighted in red in that post.

              Lets rewind. You wrote:
              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"
              To which I contended that, while not the optimized modern procedure, at proximity to stall (onset of stickshaker) in this aircraft (a Dash 8 ), when not pitching up 10° or even 1°, it should be possible to recover with power alone.
              I can reconcile "not pitching up" with "recovering with power alone". The short-term power-alone recovery that I explained earlier works because the plane pitches up, and in normal circumstances the plane will pitch up if the action taken is power alone.

              I suspect that you mean "add power and hold the pitch", which I would not call power alone, because it involves actively using the elevator to reduce the AoA. Yes, it works.

              I also added that this procedure (power first, then manage pitch) would involve a forward pressure to prevent pitching up (NOT hands-off) and ideally reduce pitch slightly but not so much that results in a significant loss of altitude.
              Ok, I suspected correctly.

              Since power=airspeed and airspeed lowers AoA if elevator (forward pressure) maintains current pitch, I can't find in your reply why this isn't true.
              It is true, it works.

              The problem is that the old procedure didn't mention AoA or stickshaker. The piltos didn't fully understand how this procedure worked, a lot of emphasis was put on preserving altitude rather that reducing AoA. AoA was not even mentioned, silencing the stickshaker was not even mentioned!!!

              Pilots failed the test if they lost more than 100ft. Even if the stall was initiated at 2000ft. Now, I understand that the old procedure would have worked most of the times, but imagine the mindset of the pilot with that kind of procedure, training and threats (not crashing, but failing the test).

              And how would that work if the stickshaker activates during a go around or take-off where you already had full power? Ah, that was a different procedure.

              And if it happened at cruise where there can be not enough power to recover in this way? Another procedure.

              And if the stickshaker happened in approach but as the result of a sudden tailwind, loss of headwind or widshear? Another procedure.

              And if it was not just a stickshaker but a real stall? Another procedure. Interstingly enough, this procedure typically warned that it can be hard to tell if the plane was fully stalled or not.

              All these procedures worked because they meant "reduce AoA". So why don't replace all them with one that says "reduce AoA"? They did.

              EX: a Dash 8 is flying at 6° ANU and speed gradually falls off, thus increasing AoA to stickshaker (approach-to-stall margin below critical angle). Pilot first firewalls throttle, then applies yoke pressure as needed to maintain 6° ANU. Not the safest course of action but shouldn't that work?
              As I said, yes it should work. Not only that, but perhaps that is the safest course of action... if the stall was exactly because of that and it is executed exactly as that.

              But again, the pilot would not know that the reason for the stall was the speed gradually decaying, or he would have stop that trend stop of the stickshaker. If the stall is because an important sudden loss of airspeed (combined with something else like the pilot, human or otto, pulling up to prevent the nose from going down, because loss of airspeed by itself, even below the "official" stall speed, doesn't increase the AoA and hence can't cause a stall), then hold the pitch may be not enough pitch reduction. It can even be pitch increase.

              But isn't the problem in both cases flawed procedure? Why must we choose between these extremes, between stall and CFIT?
              Well, in extreme cases you might be able to avoid either stall or terrain but not both.

              In any case, it would be flawed execution of the procedure, not necessarily flawed procedure.

              And, of course, the real issue here is that the PF did not use any procedure to lower the AoA at stall warning, but rather let the airplane pitch up into a stall.
              We don't know yet what the pilot did. They were in manual flight since before the event. I imagine that the pilot did something with the elevator but, as you say, not precisely reduce the AoA. If he had just applied full power, I would expect the plane to recover initially from the stickshaker and for this recovery to last well past 10° ANU. None of these two things happened.

              A final comment (for this post at least). I advocate to stop using the words "pitch", "nose" and "lower" as part of the stall recovery discussion (at least regarding the initial response). It tends to make people think that to reduce the AoA something other than the value of the AoA itself must go down (the pitch, the nose, the altitude, the airplane). Let's use "reduce AoA" instead and, if we want to speak about the control to effect that, let's say "move the elevator/yoke/stick forward", not push or push 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


              • #37
                Originally posted by Gabriel View Post
                A final comment (for this post at least). I advocate to stop using the words "pitch", "nose" and "lower" as part of the stall recovery discussion (at least regarding the initial response). It tends to make people think that to reduce the AoA something other than the value of the AoA itself must go down (the pitch, the nose, the altitude, the airplane). Let's use "reduce AoA" instead and, if we want to speak about the control to effect that, let's say "move the elevator/yoke/stick forward", not push or push down.
                But doesn't that go against the primary instrument mentality? You fly by the primary instruments. The procedures are written in that way. "Reduce pitch" is an instruction to achieve a goal on the instruments. I sincerely hope that anyone with a real pilot's license knows that this is done primarily with the elevator. The essential thing is to reduce AoA; the means to do this is to use elevator but the goal is to reduce the pitch indication on the artificial horizon (or the real one, if that's available). I think procedures need to be written in terms of primary instrument indications (and even if you have an AoA indicator, it is not a primary instrument). As we've exhaustively agreed, pilots need to know the relationship between AoA and stall before climbing into anything with wings but in that stressful, unexpected moment, the reflex must be to take simple actions with a clearly indicated goal: Reduce pitch indication with elevator: Push yoke (gently). Increase airspeed with power: Push throttle levers (smoothly).

                Comment


                • #38
                  Okay let me toss my $0.02 into this lively debate...

                  Gabriel, I think everything you wrote makes sense and is correct... from a particular perspective. If you're a skilled engineer on the ground analyzing something that happened in hindsight, it's very plausible to carefully examine airspeed, pitch, AoA, and the rates of change of all those things to determine exactly what would have do be done with the elevator and power to change the trends in those parameters to ones that will restore the aircraft to a proper flying situation. However in situations like the one that's the subject of this topic, you're going to have someone who probably is not a skilled engineer needing to make a decision on what to do, possibly in less time than it took me to write that last sentence! And skilled engineer or not, humans tend to be bad at making decisions in only a second or two, and the situation gets worse the more complex the factors to the decision are.

                  The upshot of all that being that while analyzing and formulating a detailed and accurate plan to reduce AoA may be the best option in theory, "push the nose down and add power" may be the best option in a practical situation where a human is having to make a decision in a split second. and yes I realize that doesn't address the question of how much to lower the nose! But IMHO "if the plane is about to stall, lower the nose" is a good starting point.

                  The other thing I'm surprised hasn't been brought up here is the rate at which different corrective actions take effect, and I think that's an important factor.

                  "Lowering the nose" or whatever you prefer to call it takes a moment to have an effect, but especially in turbine aircraft its action is a lot faster than increasing power. To reduce AoA by increasing power, first the engine(s) have to spool, then the airspeed needs to increase and both of those things take significant time. Lowering the nose of course isn't instant either as it requires the aircraft to rotate about its pitch axis, but that will almost always happen faster than an airspeed increase in response to a throttle change.

                  Here's another thing that came to mind as I wrote this: keeping with the theme that humans make better split-second decisions if the decisions are made simple, lowering the nose to stop or reverse a stall is the only option that will always work (assuming the aircraft is intact and the flight controls are working properly). While total loss of engine power is pretty unlikely in a 747, having the engine not respond in a piston single is a very real possibility. So while pitch and power (which combined make AoA) changes can both be used to stop or recover from a stall, changing pitch is the more reliable option if you only have enough working brain cells to do one.
                  Be alert! America needs more lerts.

                  Eric Law

                  Comment


                  • #39
                    Originally posted by Gabriel View Post
                    In any case, it would be flawed execution of the procedure, not necessarily flawed procedure.
                    Yes, I meant flawed execution of procedure. I thought that was obvious by the context.

                    Comment


                    • #40
                      Originally posted by elaw View Post
                      Okay let me toss my $0.02 into this lively debate...
                      The upshot of all that being that while analyzing and formulating a detailed and accurate plan to reduce AoA may be the best option in theory, "push the nose down and add power" may be the best option in a practical situation where a human is having to make a decision in a split second... lowering the nose to stop or reverse a stall is the only option that will always work (assuming the aircraft is intact and the flight controls are working properly)....
                      Indeed!

                      Yeah, there's all sorts of caveats (including whether you have a critical altitude situation or thousands of feet to burn).

                      But the overall management and underlying concepts are not all that complicated!

                      1) Punch yoke slightly forward
                      2) Power up
                      3) Check airspeed (and overall situation)
                      4) Evaluate if further attitude adjustments are appropriate.
                      (Including whether a careful-but-firm transition to a high-performance climb OR further nose-down inputs are appropriate)
                      5) Go to 4 (until you are established in fat, dumb and happy flight)

                      But in this situation or that situation or this twist...and "a little yoke shove" is the motion- regardless of the semantics for the occasional situation where you are actually "relaxing the pull up" or underslung slow responding turbofans or PT-6s at 100% RPM ready to dig in.
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #41
                        Originally posted by 3WE View Post
                        Many procedures end with "climb" X-hundred feet straight ahead;" and in some cases reducing attitude was vehemently discouraged.
                        I'm not aware of any procedures that require climbing before exit, but the Dash-8 approach-to-stall procedure at Colgan, for example, was to maintain altitude with a +/- 100ft margin of error to pass the checkride. With the benign characteristics and abundance of power of the Q400, this was demonstrated to be an effective procedure even with configuration changes as part of it. Reduction in pitch was not usually required but the stickpusher would kick in if it was.

                        Comment


                        • #42
                          Originally posted by Evan View Post
                          But doesn't that go against the primary instrument mentality? You fly by the primary instruments.
                          During a stall or approach to stall, nothing is more "primary instrument" than the AoA indicator, even if that AoA indicator is a rudimentary, binary on-off alarm that can indicate only 2 values: "AoA ok" and "too much AoA".

                          The procedures are written in that way. "Reduce pitch" is an instruction to achieve a goal on the instruments.
                          Yes, but it the wrong instruction in a stall or approach to stall.
                          As I am tired to repeat (and you said yourself), the pitch can be held or even increase while the AoA is reduced, and that would be perfectly ok for a stall or approach to stall recovery.

                          I sincerely hope that anyone with a real pilot's license knows that this [reduction of pitch] is done primarily with the elevator.
                          And I sincerely hope that reduction of AoA is primarily done with the elevator.

                          The essential thing is to reduce AoA; the means to do this is to use elevator but the goal is to reduce the pitch indication on the artificial horizon (or the real one, if that's available).
                          No. The goal is to silence the stall warning.

                          I think procedures need to be written in terms of primary instrument indications (and even if you have an AoA indicator, it is not a primary instrument).
                          If you have an AoA indicator, it should be a primary instrument, especially for slow flight. For example, you would not need to have variable approach speeds in function of the weight. All the escape maneuvers (CFIT escape, windshear escape) would be much easily done: You can pull up to the "red line" in the AoA indicator (which would match the stall warning). You don´t need to "modulate" the elevator to go in and out of the stickshaker to ensure that you don't go too up with the AoA but you aren't leaving "useable AoA" out either. The AoA indicator should be right in the PFD (in my view, it would be simply an "airspeed vector" cue, and the vertical distance from this "airspeed vector" to the airplane symbol is the AoA; as a side the lateral distance would be the sideslip and you can get rid of the "ball" or the sideslip indicator in the bank index). Airplanes fitted with a PLI (pitch limit indicator) already have basically that, except that it only indicates the max you can pull up (but it is variable: if you pitch up at constant AoA, the PLI keeps moving up).

                          If all you have is an on-off alarm, or even a natural alarm like stall buffet, that is the primary indicator during an approach to stall or stall recovery.

                          As we've exhaustively agreed, pilots need to know the relationship between AoA and stall before climbing into anything with wings but in that stressful, unexpected moment, the reflex must be to take simple actions with a clearly indicated goal:
                          Fully agree.

                          [quoteReduce pitch indication...[/quote]
                          Fully disagree. Reduce pitch to what value? What is the goal? Just to reduce? How much?

                          The goal is reduce the AoA at least as necessary to silence the stickshaker.

                          with elevator: Push yoke (gently). Increase airspeed with power: Push throttle levers (smoothly).
                          I would never say "gently" since in some cases it may take full forward yoke to the stops and then some nose-down trim to silence the stickshaker (and I am not necessarily talking about fully developed stalls, in extreme cases the above can be true for situations of just onset of the stickshaker too). The reduction of AoA must be at least as necessary to stop the stickshaker. And that can take anything between a slight relief of back pressure to a full forward yoke + nose-down trim.

                          If ground contact is NOT of immediate concern (and it is not 99.9% of the times, and this case was no exception at the onset), you don't need to be too cautious with the reduction of AoA. You can be liberal, reduce it quickly to a comfortable value, and once you recovered from the stickshaker, then recover the desired flight path by using normal pitch and power. A stickshaker with anything more than a few hundred feet should not be a stressful situation where you have the mindset that you need to be very precise to survive. Attempt to precision has the risk of failing to the "bad" side (there is only one "bad" side when ground contact is NOT of immediate concern, so better go comfortably away from that side).

                          If ground contact IS of immediate concern (you have two bad sides), then you have to take the risk and do all what you can to clear the ground while not stalling the plane at the same time. And that is to reduce the AoA just, barely as needed to silence the stickshaker (and then modulate the elevator to keep the AoA around the onset, i.e. intermittent sitckshaker) and simultaneously add full power. I would leave the "smoothly" part aside, I would rather say "immediately". The current consensus procedure puts too much caution on the power in my opinion (I made this comment as soon as it came out). The concern being the nose up moment of the thrust for airplanes with engines under low wings. But as I've said, I don't know of a single case where it would have not been possible to stop the stickshaker with proper use of elevator + trim.

                          --- 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


                          • #43
                            Originally posted by elaw View Post
                            Okay let me toss my $0.02 into this lively debate...

                            Gabriel, I think everything you wrote makes sense and is correct... from a particular perspective. If you're a skilled engineer on the ground analyzing something that happened in hindsight, it's very plausible to carefully examine airspeed, pitch, AoA, and the rates of change of all those things to determine exactly what would have do be done with the elevator and power to change the trends in those parameters to ones that will restore the aircraft to a proper flying situation.
                            I used no differential equation in any of my posts. Not even a 1+1=2. It was just aerodynamic concepts. Pilots should fully understand these concepts, and internalize them, not when reacting to a real-life stall situation but way in advance, in the ground school and the sim.

                            However in situations like the one that's the subject of this topic, you're going to have someone who probably is not a skilled engineer needing to make a decision on what to do, possibly in less time than it took me to write that last sentence! And skilled engineer or not, humans tend to be bad at making decisions in only a second or two, and the situation gets worse the more complex the factors to the decision are.
                            I fully agree. More than "decide" you have to "react". And you may have only one chance to do it right. So better you do it right the first time.

                            The upshot of all that being that while analyzing and formulating a detailed and accurate plan to reduce AoA may be the best option in theory, "push the nose down and add power" may be the best option in a practical situation where a human is having to make a decision in a split second.
                            I almost agree. Just make it clear that "push down" means "reduce AoA".

                            Man, if "Reduce AoA at least as needed to silence the stickshaker" is too much for a pilot, then something is very, very, VERY bad with the pilots.

                            ... and yes I realize that doesn't address the question of how much to lower the nose!
                            That´s a big point for MY procedure. It DOES address how much to reduce the AoA (and it may be that you don't need to lower the nose a single degree). See?

                            But IMHO "if the plane is about to stall, lower the nose" is a good starting point.
                            "Reduce AoA" is better. In many cases the nose will go down in the process, in some cases maybe not, but "reduce AoA at least as needed to silence the stickshaker" is universal, clear to execute, and has a clear goal.

                            It's as universal, clear, practical and effective as it gets and I am having a hard time trying to understand what is bad in it for you guys.

                            The other thing I'm surprised hasn't been brought up here is the rate at which different corrective actions take effect, and I think that's an important factor.

                            "Lowering the nose" or whatever you prefer to call it takes a moment to have an effect, but especially in turbine aircraft its action is a lot faster than increasing power. To reduce AoA by increasing power, first the engine(s) have to spool, then the airspeed needs to increase and both of those things take significant time.
                            I fully agree, and I never proposed that. I just said that it works (if the nose-up moment of the thrust doesn't cancel the nose-down moment of the pitch-up motion that comes after the increase of speed).

                            I've said once and again that the main means to control AoA is the elevator (including trim in airplanes with a movable horizontal stabilizer).

                            I've even said that the immediate application of power is only necessary (and let me clarify that it doesn't replace what was said in the previous sentence) if and only if ground contact is of immediate concern. If not, it's much easier, safer and comfortable to first reduce the AoA liberally, and then, once recovered from the stall or approach to stall, resume normal flight using normal pitch and power inputs.

                            --- 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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                            • #44
                              Maybe I haven't said this clearly enough...

                              ...maybe WE don't need procedural improvements and improved word-choice as much as WE need to do an occasional review of stalls and maybe even a take-it-past-the-stick-shaker-to-the-ragged-edge practice run on the simulator once a year.

                              not that WE actually know what we're talking about...
                              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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