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  • #46
    Originally posted by 3WE View Post
    5a. I object to absolute statements
    5b. ESEPECIALLY when YOUR way is the ONLY way to fix human factors.
    Let me know when you spot the irony there.

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    • #47
      Originally posted by Evan View Post
      Let me know when you spot the irony there.
      Indeed, one little fat finger f-up on your beloved touch screen airplane and the plane may do wrong.

      Cue the fundamental that you almost always have your hands by a 'direct' control.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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      • #48
        The clock is still ticking: tic, toc, tipms, topms. It is a matter of time until we have the NEXT deaths.

        http://avherald.com/h?article=4cb53df5&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 ---

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        • #49
          Originally posted by Gabriel View Post
          The clock is still ticking: tic, toc, tipms, topms. It is a matter of time until we have the NEXT deaths.
          If we are going to use technological solutions, we also need planes to weigh themselves and enter that data automatically (or at least the flag a conflicting pilot entry).

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          • #50
            Originally posted by Evan View Post
            If we are going to use technological solutions, we also need planes to weigh themselves and enter that data automatically (or at least the flag a conflicting pilot entry).
            A320 family does that. At least the ones we have do.

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            • #51
              Originally posted by Evan View Post
              If we are going to use technological solutions, we also need planes to weigh themselves and enter that data automatically (or at least the flag a conflicting pilot entry).
              First of all, no we don't. You need to compare the actual acceleration with the acceleration used internally to compute the take-off performance.
              Second, you can have the plane weight itself without adding any hardware. The FADEC knows the thrust the engines are producing given the engine parameters and environmental factors like static pressure and temperature. In the beginning of the take-off roll, where drag is negligible, thrust/acceleration=mass.

              --- 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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              • #52
                Originally posted by Gabriel View Post
                First of all, no we don't. You need to compare the actual acceleration with the acceleration used internally to compute the take-off performance.
                Second, you can have the plane weight itself without adding any hardware. The FADEC knows the thrust the engines are producing given the engine parameters and environmental factors like static pressure and temperature. In the beginning of the take-off roll, where drag is negligible, thrust/acceleration=mass.
                I'm sorry, I meant we also need planes to weigh themselves to prevent (or at least flag) these data entry errors, not that we need them to do that in order for TOPMS to work.

                The mass calculation method is interesting. If it works it could extend that function to antique airframes like the 737.

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                • #53
                  The more I think about this- I am not sure how to get around a math error (yeah, sure, make auto weighing/auto everything, since MCAS works so awesome).

                  Double check all you want, but if a math error is made, the TOPMS is going to be telling you that a not_OK takeoff is fine.

                  And any human double-checking thing is going to be affected by the same math error.
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #54
                    Originally posted by 3WE View Post
                    The more I think about this- I am not sure how to get around a math error (yeah, sure, make auto weighing/auto everything, since MCAS works so awesome).

                    Double check all you want, but if a math error is made, the TOPMS is going to be telling you that a not_OK takeoff is fine.

                    And any human double-checking thing is going to be affected by the same math error.
                    I don't follow you. What kind of math error do you have in mind? For example?

                    --- 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


                    • #55
                      Originally posted by Gabriel View Post
                      I don't follow you. What kind of math error do you have in mind? For example?
                      Don't got over nit-picky black and white.

                      On rare occasions, we are taking out lights and walls and stuff. This comes from errors. Math errors, or brain farts, or bad data supply, whatever- the crews try to take off with inadequate power.

                      So, the same error, brain fart or bad data goes into your TOPMS system...OK...Maybe I have a brain fart…The TOPS will note that the plane is not speeding up like it should.
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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                      • #56
                        GA is not immune...

                        I will give some thought (engineering thought) to this 70% 50% rule. My instinct says it is not correct neither in the form stated by Dan nor in the form stated by the surviving pilot.

                        https://www.youtube.com/watch?v=ZNUvC5IbybQ

                        --- 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


                        • #57
                          Originally posted by Gabriel View Post
                          GA is not immune...

                          I will give some thought (engineering thought) to this 70% 50% rule. My instinct says it is not correct neither in the form stated by Dan nor in the form stated by the surviving pilot.

                          https://www.youtube.com/watch?v=ZNUvC5IbybQ
                          So I skimmed through the video. What was the 'probable cause'? Did they ever determine that? If it was degraded engine performance, I suppose another rule could be to watch your engine instruments and reject before V1 if they seem off (assuming your V1 calculation includes stop distance). He seems to have a well-developed instinct for what is normal performance on that plane but he refers to it as 'a feeling', not any actual indication.

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                          • #58
                            Originally posted by Evan View Post

                            So I skimmed through the video. What was the 'probable cause'? Did they ever determine that? If it was degraded engine performance, I suppose another rule could be to watch your engine instruments and reject before V1 if they seem off (assuming your V1 calculation includes stop distance). He seems to have a well-developed instinct for what is normal performance on that plane but he refers to it as 'a feeling', not any actual indication.
                            The accident is very recent, there is no result of the investigation. The pilot reported what was apparently the engine not producing enough power (as shown by it's inability to accelerate to lift-off speed in the distance it should have and then it's inability to accelerate and climb after lift off even when they were basically at sea level and below maximum weight) but according to the pilot, while now in hindsight he realizes he had a feeling that something was not good during the take-off roll, it was not strong or clear enough as to identify a slow acceleration, and all the engine instruments read normal (that is a bit hard to believe: while not impossible, there are very few ways in which the engine can have the right manifold and right RPM and not producing the useful power that it is supposed to be delivering)

                            There is no V1 in single-engine planes (and neither in light twins). There is no accelerate-stop distance in the manuals. Accelerate-stop is based on the decision making process around one engine failing. If an engine fails in a single, you stop at whatever speed that happens. Note that V1 is not useful as a go-nogo decision in multi-engine jets either for the case of reduced performance.

                            --- 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


                            • #59
                              Originally posted by Gabriel View Post

                              The accident is very recent, there is no result of the investigation. The pilot reported what was apparently the engine not producing enough power (as shown by it's inability to accelerate to lift-off speed in the distance it should have and then it's inability to accelerate and climb after lift off even when they were basically at sea level and below maximum weight) but according to the pilot, while now in hindsight he realizes he had a feeling that something was not good during the take-off roll, it was not strong or clear enough as to identify a slow acceleration, and all the engine instruments read normal (that is a bit hard to believe: while not impossible, there are very few ways in which the engine can have the right manifold and right RPM and not producing the useful power that it is supposed to be delivering)

                              There is no V1 in single-engine planes (and neither in light twins). There is no accelerate-stop distance in the manuals. Accelerate-stop is based on the decision making process around one engine failing. If an engine fails in a single, you stop at whatever speed that happens. Note that V1 is not useful as a go-nogo decision in multi-engine jets either for the case of reduced performance.
                              Well, TOPMS would be good for all planes and seems like a no-brainer in this gadget age when your watch can tell you if you are about to drop dead.

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                              • #60
                                I concur that Dan’s rule is BS.

                                Light planes need very different rules DEPENDING on the situation.

                                For the typical long runway- if your acceleration is off and you miss your liftoff point YOU STOP. The one engine really needs to be working right.

                                Now…for truly short fields where accelerate stop is an issue…you need a speed vs distance check THAT ALLOWS YOU TO STOP.

                                There’s also a top secret method of a nice check before you are too committed, that was alluded to by a respected airline pilot.

                                Of course, Boeing Bobby’s well-trained a$$ and sixth sense is also pretty darn good.

                                Footnote: It’s possible that Dan’s rule provides decent protection, but it’s based on nothing concrete. Perhaps the general disdain that one of our friends has for him is well founded?
                                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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