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What (the heck) is it doing now???

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  • #16
    Boeing's version of "What is it doing now"?

    Aviation Herald - News, Incidents and Accidents in Aviation

    --- 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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    • #17
      Originally posted by Gabriel View Post
      Boeing's version of "What is it doing now"?

      http://avherald.com/h?article=4603ef59/0002&opt=0
      Bad instincts it seems. When applying nose-down pitch and not getting the expected response, I think the instinct should be to apply nose-down pitch trim and reduce power, am I wrong?

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      • #18
        Originally posted by Evan View Post
        Bad instincts it seems. When applying nose-down pitch and not getting the expected response, I think the instinct should be to apply nose-down pitch trim and reduce power, am I wrong?
        Well, the first problem was the jam vital flight control. That's not a good start.
        Then, they thought the AP had disconnected because the applied great force on the flight controls, even when they neither disconnected it nor had the AP disconnect warning. Think, as in believe or assume, is a dangerous thing in a plane. Don't think. Check.
        Third, we have the trim issue. I think that pilots of this kind of plane (and with that I mean where the trim is very powerful and is an independent surface from the elevator) should have a good instinct for using it as an "extension" of the elevator.
        Power, that is more tricky. I would leave it as a last resource only if elevator down and trim down is not effective. Reducing power has the obvious advantage of reducing the nose-up moment of the thrust, but with the plane 35° nose up it has the obvious disadvantage of making the loss of energy, especially speed, much more faster and hence rendering the aerodynamic controls even more useless.
        I have never seen one single case so far where elevator down + trim down would not have been enough.

        --- 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 have never seen one single case so far where elevator down + trim down would not have been enough.
          And we've seen plenty where an full ANU stab trim was cancelling out full downward elevator deflection. I think it would be instinctive by now to go to the trim switch. The other instinct I think would be to use rudder to induce roll. But I've also always thought reducing power was a commonly taught procedure with excessive, unresponsive pitch...

          Reducing power has the obvious advantage of reducing the nose-up moment of the thrust, but with the plane 35° nose up it has the obvious disadvantage of making the loss of energy, especially speed, much more faster...
          Is that true? How effective is thrust in generating airspeed at an AoA high enough for stall warning)?

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          • #20
            Originally posted by Evan View Post
            The other instinct I think would be to use rudder to induce roll.
            Noooo!!!!

            Use AILERON to induce roll, use rudder to keep the roll coordinated (avoid sideslip angles). Only if ailerons are ineffective too, use rudder, abi, with caution, to induce a sideslip and just initiate a roll. Risk of spin!!!

            [quote]But I've also always thought reducing power was a commonly taught procedure with excessive, unresponsive pitch...
            Yes, but I will not consider the pitch unresponsive until AFTER you have tried BOTH elevator AND trim (AND like in & and like in Aircraft Nose Down).

            [quoteIs that true?
            Absolutely.

            How effective is thrust in generating airspeed at an AoA high enough for stall warning)?
            Not much, but the same things that meke thrust not very effective in generating airspeed are EXTREMELY EFFECTIVE in DESTROYING airspeed in absence of thrust.

            --- 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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            • #21
              Originally posted by Gabriel View Post
              Noooo!!!!

              Use AILERON to induce roll, use rudder to keep the roll coordinated (avoid sideslip angles). Only if ailerons are ineffective too, use rudder, abi, with caution, to induce a sideslip and just initiate a roll. Risk of spin!!!
              Yeah, I meant the scenario in which you are at or above stall warning where aileron is not so effective. But of course, the first instinct I would expect to be STRONGLY present is pitch trim and as you say that should take care of it.

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