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  • #16
    Originally posted by ATLcrew View Post
    He has plenty of apostles at AA. Whether or not that's a good thing, I won't comment.
    Yeah, he's good looking, has good stage presence and gives a good presentation.

    BUT, do the methods he's preaching have a reasonable value to truly be implemented and meaningfully improve safety?

    Sure, it makes perfect sense, but calmly flying a little plane on the end of a stick while laying out 'the obvious answer' strikes me as a little sterile and devoid of reality.

    No harm talking about stuff and learning, but those stories of planes going Y2K (albeit mechanically) are disturbing and can we expect crews 'simply do the exact right thing as trained' at the fancy seminar.

    Care to comment on that?
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

    Comment


    • #17
      Originally posted by Evan View Post
      I have no sense of humour.
      Fixed
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #18
        AOA where rudder = ailerons.

        Gabriel:

        Can you explain this in one paragraph?

        I'm struggling to understand.

        If you double the speed you get 4X more of "potential" everything, right? 4X drag, 4X potential lift, I'd think 4X more ailerons AND 4X more rudder.

        Why do the ailerons become more powerful and the rudder weaker? (that's in relative terms)

        Not only that, when you get slow/high AOA, the tail and rudder often operates in some of the "wash" of the aircraft fuselage and loses even more effectiveness...
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • #19
          Originally posted by 3WE View Post
          Yeah, he's good looking, has good stage presence and gives a good presentation.

          BUT, do the methods he's preaching have a reasonable value to truly be implemented and meaningfully improve safety?

          Sure, it makes perfect sense, but calmly flying a little plane on the end of a stick while laying out 'the obvious answer' strikes me as a little sterile and devoid of reality.

          No harm talking about stuff and learning, but those stories of planes going Y2K (albeit mechanically) are disturbing and can we expect crews 'simply do the exact right thing as trained' at the fancy seminar.

          Care to comment on that?
          for what i'ts worth, he claimed to have used those techniques on the sims for every plane in AA's fleet at the time and he claimed they worked.

          now, how accurate are sims as far as structural integrity goes? i would hope fairlly accurate but i have no clue.

          Comment


          • #20
            Originally posted by TeeVee View Post
            for what i'ts worth, he claimed to have used those techniques on the sims for every plane in AA's fleet at the time and he claimed they worked.

            now, how accurate are sims as far as structural integrity goes? i would hope fairlly accurate but i have no clue.
            Sorry, I wasn't clear...

            How valid are the procedures for regular pilots flying fat, dumb and happy on a mundane flight?

            Not sure I trust a chief pilot on a simulator in the middle of an upset recovery research program. His mindset might be a bit more cocked, primed, prepared and rehearsed.
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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            • #21
              Originally posted by 3WE View Post
              Gabriel:

              Can you explain this in one paragraph?

              I'm struggling to understand.

              If you double the speed you get 4X more of "potential" everything, right? 4X drag, 4X potential lift, I'd think 4X more ailerons AND 4X more rudder.

              Why do the ailerons become more powerful and the rudder weaker? (that's in relative terms)

              Not only that, when you get slow/high AOA, the tail and rudder often operates in some of the "wash" of the aircraft fuselage and loses even more effectiveness...
              Sure. There is a point, at high AoA, where you cannot extract more lift from the airfoil, be it by increasing the AoA further or equivalent means like increasing the chamber (i.e. lowering an aileron). The down-going aileron stalls and compensates the reduction of lift of the up-going one in the opposite wing.

              The tail is always at zero AoA (before you press a pedal), even if the wing is at high AoA, and hence the rudder retains the power to increase the CL of the fin (not the lift of the fin itself, because slower speed will mean lower lift for the same CL.

              At the same time, the effect of increasing speed of the forward-going wing vs reduction in the back-going wing (yaw) is relatively more important at slow speeds compared with the "base" airspeed.

              But basically paragraph 1 explains it, so I consider I met your 1-paragraph requirement.

              --- 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


              • #22
                Originally posted by Gabriel View Post
                But basically paragraph 1 explains it, so I consider I met your 1-paragraph requirement.
                No you didn't

                I find it hard to believe that in the 737 hard over crashes they were so slow that the ailerons stalled.

                I would think that they had good airspeed when the rudder kicked over.

                I understand the concept of aileron stalls but am troubled that they can happen to an airliner which is 'always' flown with a nice safety buffer from a stall. I do not recall the planes in hard over crashes being on the slow side.

                I do get it that the 737 hard overs involved planes that had slowed some- but (getting redundant) slow enough that the ailerons stall? Do we need to ban all ailerons and only use spoilers for roll? (Said tounge-in-cheek)

                Thanks in advance for additional paragraphs.
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • #23
                  Ok, here we go again. First of all, who (other than you) said anything about speed? It's AoA. Didnt you see how this pilot/instructor uses the ELEVATOR as roll control? (with the rudder fully deflected to one side and the ailerons fully deflected to the other).

                  So I have more than one paragraph. Thanks. I could get away with it by saying, in one line, look at the video again, but this time pay attention. But I'll take it.

                  So speed and AoA are related, sure, but not perfectly correlated.

                  You are flying at a typical approach (which is a somehow slow) airspeed.

                  Bam! Full left rudder deflection. Now lets go slow motion:

                  The right wing moves forward increasing its speed, the left wing moves back diminishing its speed. Note that this delta speed is a bigger proportion of the nominal speed the slower you go in the first place. The lift increases in the right wing and diminished in the left wing. You start to roll left.

                  Now, because of the dihedral effect (caused by geometrical dihedral, wing placing -which is negative in this low-wing case-, and wing sweep), the wing that is forward makes more lift than the wing that is back. Even if the sideslip stopped increasing, the now steady sideslip still creates left roll.

                  The plane banks left, you apply full right yoke. The roll stops. Additionally, a good bunch of the lift in the right wing (wich was making more lift than the left wing to begin with) is lost with the full deflection of the roll spoilers.

                  So, You are in a bank,you have not pulled up yet, you need more than 1G to keep the nose up so the nose goes down, you have full left rudder in a left bank so the yaw also takes the nose down, you have killed a good bunch of your lift filling your best lifting wing with spoilers, so now you don't even have 1G, hence the nose goes down. (note however that none of these effects reduce the AoA)

                  Bottom line: THE NOSE GOES DOWN! What is down? The ground (and not so far).
                  What does a "reasonable" pilot does: Pull up. What happens then? The AoA increases.... AT THE SAME SPEED!!!!!!!!

                  Look again at the videos: The pilots lose it when they pull up. In every single case. Both in the animations of the real accidents and in the Boeing flight tests. In the real accidents this is aggravated by the pilots still pulling up after rolling inverted. Now up is down and 1G is 2g down (note G, the load factor, vs g, the acceleration in free fall). Not to mention that they always got stickshaker, very likely fully stalling the plane, and now yes you can forget of any roll stability and authority that you might have had left.

                  (Side rant: I hate the "G" nomenclature. I use it just because it's so standard that it's almost impossible to communicate without using it. Now, what is G? The acceleration of gravity, is the usual answer. BULSHIT! How many Gs does an unaccelerated flight have? Zero G? No. One G. The Gs are no acceleration, unless you refer the position of the plane to a free-falling frame of reference. Then yes, while the frame free falls toward the ground with an acceleration g -the small g, the acceleration due to the gravity, which is not the big G- your plane flying straight and level at 1G is accelerating up in this frame at 1g. When you are at 1G straight and level, you are in steady flight with an acceleration of zero g. If you are at zero G, you are in free fall accelerating 1g down. If you are inverted straight and level, you need -1G to keep zero g -unaccelerated flight-, if you have zero G you are again at free fall, if you are at 1G, now you are accelerating down at 2g twice the acceleration of the gravity, twice worse than free flight. So what is "G". In a dimensionless unit. The best term would be "a load factor of 1" or "N=1", not "1G". And what is the load factor? Very easy: The ratio of lift/weight. Two forces than don't need to be in the same axis (that's why you can be at 1G in a turn, when the the lift is tilted and the weight always points to the center of the Earth). And because it's the ratio between two entities of the same kind (forces in this case), the ratio is dimensionless.)

                  Ok, now let's change the experiment. Fly at approach speed, smoothly add rudder and use ailerons to keep the wings level. Also keep the altitude.

                  So, a bit of left rudder, a bit of right aileron, a more of left rudder, more of right aileron, full left rudder, somewhere near full right aileron. Good, we made it!!! Except.... We have near full roll spoilers in one of the wings. Now the lift < weight and the nose goes down, we have or second goal, so we pull up to hold the altitude. Great, this stopped the nose-down movement (nose is still down but not going any lower), we hat to pt more ailerons because we now are at a higher AoA, but we've got it. Full rudder, full opposite aileron, we keep 1G at higher AoA that what we would normally required at this speed if we hadn't all those spoilers deployed. Except that we are still descending. At 1G but descending. If we want to stop the descent, and even more climb to return to our original altitude, what do we do? Pull up, increase AoA a little bit more, and up... ehm... sorry, left we go. And that's at the same speed (but higher AoA) that you had at the beginning.

                  In other words, the crossover speed doesn't take into account the AoA you need to keep 1G at that speed, but the AoA you need to keep 1G at that speed with full aileron input (including all the roll spoilers fully deployed in one wing), which is a higher AoA than the normal one you would need to fly at that normal speed.

                  Let's go back to the aileron stall. The FARs require that the ailerons must be responsive (and not reversed, which would be another kind of "resposniveness") all the way to the stall. (but they don't require the same of the roll stability, that's why it's an awful idea to do ailerons inputs after the stall warning). At this crossover speed the plane will not be at stall AoA even considering more AoA to compensate the loss of lift due to full roll spoilers deflection in one wing. So why did the ailerons became irresponsive? They didn't. If you think that they are irresponsive because you have full right aileron and the plane still slowly banks left, try to neutralize the ailerons and look how quickly it rolls inverted left. They just lost some of its resposiveness, enough so that now full rudder in one direction can overcome in roll power full ailerons in the other.

                  And why, as AoA increases, do ailerons lose resposniveness faster than the rudder? Any control surface loses resposiveness at higher AoA when they deflect in a direction that would increase the lift of its main fixed surface (like the aileron deflected down in the up-going wing).
                  I used the term "aileron stall" somehow losely before. What is an "aileron stall"? There is no such a thing until you start to consider stall = detached airflow. The airflow will detach from one of the sides (the obvious one) of the control surface at a somehow small angle of deflection, say 15 degrees. At that point, the pressure on that side of the control surface stops dropping with increased deflection, as it had been doing before that limit. However, increasing deflection still makes sense because the pressure keeps increasing in the other side of the control surface (and not only there, the pressure will increase on that side of all the airfoil, even ahead of the control surface, I mean if the flow is not supersoning because then it cannot know let alone care what happens downstream of if the aileron is deflected at all before reaching it). However, its effectiveness per added degree of deflection will diminish compared to what it was when the flow was attached at both sides.

                  But if the main surface was already flying at a somehow high AoA, the separation on one side of the control surface (and the reduction of effectiveness) begins at smaller angles of deflection.

                  So this is why the ailerons are less effective when the wing is at a high AoA, and why the crossover speed is slower with a higher flaps setting (because you can have the same AoA at a slower speed).

                  On the other hand, note what happens with the fin+rudder. You apply full left rudder, the airplane yaws left and the wind starts hitting the fin from the right. So the rudder is deflected in a lift-diminishing direction, and it doesn't lose effectiveness, like the aileron deflected up in the down-going wing.

                  The video:
                  Audio and video restored versions of this video:Part One: https://youtu.be/hTA3xE_tl6UPart Two: https://youtu.be/Sk1dlwX40DIAn American Airlines Advanced Air...


                  Look again the animation of the accident starting at 5:50 - 8:10. pay attention to what the instructor says to pay attention: the relationship between AoA (yoke pull-up) and roll. Look in particular the last 10 seconds between 8:00 and 8:10.
                  Also look at his introduction of the Boeing videos at 8:30 when he say "... to show crossover alpha, now they call it crossover speed because they don't have an angle of attack indicator, but it's really an lapha issue, you can use speed only to correlate to AoA if you keep the plane all the time at 1G, and I don't know what you think but these accidents looked quite dynamic to me."

                  Finally check, 17:45 - 19:15, especially the 10 seconds in 18:30 - 18:40.

                  And, please, speed is very important, but be careful how you use that word. Because speed is related to AoA but is NOT AoA.

                  --- 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


                  • #24
                    Oh &&&&)!

                    I asked for it. Probably need to re read it, but I get it that several things 'conspire' to kill that safety buffer.

                    My bad for asking for the paragraph limit.

                    Thanks....I think
                    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #25
                      Really cool stuff. Vanderburgh's presentations are interesting and I think they contain some very useful material. It would be such a pity if what this guy did contributed to the AA587 disaster. Or maybe things were just taken out of context somehow down the hierarchy.

                      I didn't see Vanderburgh talk about wake turbulence and advising aggressive use of the rudder, or leveling the wings off using the rudder by default, but somehow that is what some pilots took away from the AAMP. So I found this relevant information, even though I couldn't find Vanderburgh's opinion on AA 587:





                      About the previous incident cited in the above link:


                      USA TODAY delivers current national and local news, sports, entertainment, finance, technology, and more through award-winning journalism, photos, and videos.


                      Comment


                      • #26
                        Originally posted by 3WE View Post
                        Yeah, he's good looking, has good stage presence and gives a good presentation.

                        BUT, do the methods he's preaching have a reasonable value to truly be implemented and meaningfully improve safety?

                        Sure, it makes perfect sense, but calmly flying a little plane on the end of a stick while laying out 'the obvious answer' strikes me as a little sterile and devoid of reality.

                        No harm talking about stuff and learning, but those stories of planes going Y2K (albeit mechanically) are disturbing and can we expect crews 'simply do the exact right thing as trained' at the fancy seminar.

                        Care to comment on that?
                        I'd love to, except that I'm not real clear on what you're actually asking.

                        Comment


                        • #27
                          3-dubya, i think you're missing something here. vandenberg's lectures were just part of the training these guys got. the methods he lectured on were taught, and tested in the sims as well. if you listen to him carefully you'll ear him talk about doing some of this stuff by memory--a la evan, if you will.

                          he also talks about the need to react and then think. a valid point--to an extent anyway.

                          i watched this video about some danish (i think) thrill/challenge me type guy, who learned to fly from zero and in one month, flew a 737--taxi, takeoff, landing, takeoff, landing.

                          his instructor told him flat out, "in a jet, things go wrong VERY fast. you have no time to think. you REACT. or, you die.

                          goes back to memory items evan is so fond off. but perhaps a step further.

                          i think vandenberg's goal was to identify seriously effed up flight regimes, teach pilots how to recognize them, how to react, and how to save their asses, not to mention the self-loading cargo in the back.

                          where's bobby when you need him???????

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                          • #28
                            Originally posted by TeeVee View Post
                            where's bobby when you need him???????
                            Upsetting.... errr.... flying a deformed 747?

                            --- 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
                              Tee Vee, that is what the cartoon Pink Panther is all about. As a James Bond "karate" take off, note the diminutive assistant who continually lurks in the shadows, above and below and launches attacks that the panther effortlessly wards off without blinking an eye or showing any emotion.

                              This is from an old martial arts concept called "Mu Shin" .... or "No Mind", and the one way achieves that state is to practice, practice and practice some more. That is why a fight seems slower to a skilled fighter. A truly great pilot or fighter could develop this to the point where they are working out a dinner guest list in the middle of the fray ... ok, not quite but you get the idea. This started with a swordsman "Mushashi" who's mantra on the secrets of greatness ended each lecture with "practice this daily".
                              Live, from a grassy knoll somewhere near you.

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                              • #30
                                yes, i am aware of this concept. all humans have it to an extent. walking for example, is not just a matter of learning how to move one foot forward then the other. it is balance, which your body constantly adjusts, most of the time without you being aware of it. hitting the brakes when even in your peripheral vision your brain sees brake lights in front of you. typing without looking at the keyboard (mostly just muscle memory but includes a spatial factor as well).

                                and just as each martial arts practitioner will not achieve the highest level, it is quite expected that not every pilot will. moreover, top level martial artists literally spend their entire lives dedicated to training while it is not practical for pilots to do so.

                                sure, it would be nice, and evan would be ecstatic, if every airline was forced to pay its pilots for 2 full months of training every year. where pilots practiced every conceivable upset in sims and maybe a few real life ones as well, all while getting paid their full salaries. ever gonna happen? not in 200,000,000 years.

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