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New 747F waves Boeing field goodby. Safe? Sane?

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  • #16
    Originally posted by Evan View Post
    One thing transport aircraft are not intended to do is roll reversals. Is this as dangerous as rudder reversals?
    You mean from a structural point of view?

    Yes, they are equally dangerous since the structural requirement for the ailerons and wings don't ask for, for example, to be established in a max roll rate in one direction and apply full roll input in the other direction.

    That said, at that speed the risk of structural failure for such an aileron reversal (or rudder reversal) is nonexistent.

    --- 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 elaw View Post
      So you're saying you can't turn right after you've turned left?

      I'm pretty sure if airplanes could ever only turn in one direction they would not be considered as useful as they are, except maybe in NASCAR.
      He said roll reversal, not bank reversal.

      --- 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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      • #18
        Originally posted by elaw View Post
        I'm with 3WE on this.

        Airplanes don't stall (and therefore crash) because of safety, insanity, risk, or violation of rules (or the appearance thereof). They stall because of physics. If the wing on your plane will stall at an AoA of 12.5 degrees, and you can perform a maneuver like the one in the video without ever exceeding 12.5 degrees AoA, the plane will not stall. Which seemingly was the case here because the plane remained airborne.
        Yes, that's correct.
        And an airplanes doesn't crash until it hits the ground so contouring the landscape at 400 MPH 20 ft above the ground I guess it's just ok... until you are not longer 20 ft above and crash.

        So... the plane won't stall until it exceeds 12.5 deg of AoA, but it does stall when it exceeds it. And certain maneuvers increase the risk.

        --- 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 TeeVee View Post
          why is this even being discussed? the guy knew what he was doing and did it. end of story.
          Guys, what's up with all you today?

          You meant that if a pilot buzzes the barn 100 times with no issues we only criticize him for being dangerous when he crashes in the 101th attempt?

          Thanks God that you are not the ones making the rules and dictating policies 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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          • #20
            Originally posted by 3WE View Post
            I watched the video again closely, but could not make out the yoke position. You have some good eyes.

            That being said, the maneuver looked rather smooth to me.
            When you have a 400 tones airplane flying somehow close to the minimum airspeed it would fly, response to control inputs is not the quickest, especially not with the ailerons that loose effectiveness at high (eve pre-stall) AoAs.

            That's bad for control authority, but good for overload prevention.

            --- 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 3WE View Post
              Well...

              Of the zillions of rules (and rules of thumb) on how to fly an airplane, you are generally supposed to gain 300 to 500 feet of altitude (at least that's the light plane version) before doing much banking, and even then...keep it gentle down low.

              So Gabe probably does have himself a violation here.

              As to whether it's safe or not or whether the violation is of a real rule or a rule of thumb...

              ...that and I guess maybe discussing aviation is what you do on an aviation discussion forum.
              The saying goes:

              There are three kinds of rules:
              1- Rules that you should not violate (common sense, good practices, etc...)
              2- Rules that you must not violate (laws, regulations, procedures)
              3- Rules that you can not violate, even if you try hard (laws of Physiscs)

              Note that while can not is stronger than must not which in turn is stronger than should not, all three are negative.

              --- 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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              • #22
                And by the way,

                Note that you don't need to violate any written rule to be in violation with the FAA. If you do something that the FAA judges an unjustified risk for no good operative or safety reason, then you are flying carelessly recklessly, which is forbidden by the federal regulations (well, it seems that you will be violating a written rule after all).

                So even the type-I rules (... shall not...), including the rules of thumbs, can put you in legal problems if you don't comply with them.

                --- 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


                • #23
                  Originally posted by Gabriel View Post
                  When you have a 400 tones airplane flying somehow close to the minimum airspeed it would fly, response to control inputs is not the quickest, especially not with the ailerons that loose effectiveness at high (eve pre-stall) AoAs.

                  That's bad for control authority, but good for overload prevention.
                  I concur that he violated the rules of comfortable passenger hauling, and maybe even some rules of thumb...

                  That being said, landing in a gusty cross wind's going to get some quick and moderately intense control inputs...all of which take place with higher-end AOA's and lower-end airspeeds and minimal extra altitude.

                  Until you run the numbers and can show me he's significantly closer to "the edge" than Flyboy turning final on speed on the Carnsie/Whatever visual approach on a gusty night, I'm going to say maybe he was light and had a little extra speed and let him have his little wave and call it cool.
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #24
                    Originally posted by 3WE View Post
                    I concur that he violated the rules of comfortable passenger hauling, and maybe even some rules of thumb...

                    That being said, landing in a gusty cross wind's going to get some quick and moderately intense control inputs...all of which take place with higher-end AOA's and lower-end airspeeds and minimal extra altitude.
                    Any pilot that, during final approach / landing and at very low altitude, finds himself either

                    a) having to keep 4 seconds on full roll input to control the plane, or
                    b) exceeding 20 degrees of bank at very low altitude., and especially
                    c) both a) and b) at the same time

                    and doesn't immediately start a go-around is a criminal.
                    Yes, you can say that this pilot sort of did start a go-around after the maneuver. But the go-around that I say is the unintended result after something went very wrong during the approach, not the intended maneuver itself where you intentionally insert the upset.

                    Until you run the numbers and can show me he's significantly closer to "the edge" than Flyboy turning final on speed on the Carnsie/Whatever visual approach on a gusty night, I'm going to say maybe he was light and had a little extra speed and let him have his little wave and call it cool.
                    There are some cues that show that the plane was not going that fast.
                    The somehow normal rotation before the plane lifts off.
                    The fact that the plane doesn't skyrocket after lift-off (despite a good pitch angle).
                    The slow reaction to full aileron inputs.

                    In any event, I don't care.
                    Since this was way out of the book, the only way that I would approve this (not that anybody cares) is if the maneuver was planned, the risks and safety margins calculated in advance, the parameters and required performance calculated in advance too, approved by the airline competent authorities, and briefed. As airlines do (or should do) for airshow performances.

                    I can be wrong, but I have the strong feeling that this was not the case.

                    But I give up. If you want to think that this was safe and cool, I won't stop you (anymore).

                    --- 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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                    • #25
                      Interesting points, Gabriel.

                      With everything you say, how is it that there are Air Shows and Air Races?

                      At these events, numerous things take place which increase hazards compared to normal and provide no additional operational or safety advantage and violate the FAR you cite.

                      Originally posted by Gabriel Aviation Rules
                      ...If you do something that the FAA judges an unjustified risk for no good operative or safety reason, then you are flying carelessly recklessly, which is forbidden by the federal regulations (well, it seems that you will be violating a written rule after all).
                      It's amazing at airshows when a plane takes off and almost immediately goes into a barrel roll...Must have something to do with good energy and attitude management...the kind you might use to rock the wings on a 747 just after takeoff.

                      ...and apologies, I missed your air-show comment. I also missed the part of the film that shows how they did not discuss the performance parameters and brief for the maneuver.
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #26
                        Yes.

                        --- 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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                        • #27
                          Originally posted by brianw999 View Post
                          Tex Johnson. B707. Full barrel roll. Nuff said ?

                          http://m.youtube.com/watch?v=Ra_khhzuFlE
                          It's important to note that it's not Tex Johnson, but Tex Johnston, with the "t" in Johnston. This poor guy has had his name misspelled so many times.

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                          • #28
                            Originally posted by Gabriel View Post
                            And by the way,

                            Note that you don't need to violate any written rule to be in violation with the FAA. If you do something that the FAA judges an unjustified risk for no good operative or safety reason, then you are flying carelessly recklessly, which is forbidden by the federal regulations (well, it seems that you will be violating a written rule after all).

                            So even the type-I rules (... shall not...), including the rules of thumbs, can put you in legal problems if you don't comply with them.
                            Do those "unwritten rules" apply to ferry flights or demonstration flights? Certainly test flights for certification involve things that would be considered too risky for a revenue flight.

                            I would worry that, with weight-saving as such a primary concern, airframes may not be as overbuilt as they used to be. Built to exceed the operational envelope by the required margin, yes, but maybe not by anything beyond that. And then there's the outsourced assembly to less experienced non-union labor degrading that margin a bit. So maybe they are less forgiving to pilots who are used to four-oh-oneing them a bit on ferry flights, just for kicks. Maybe not.

                            One thing is for sure (unless it's a trick of the telephoto lens): as an empty can that monster can climb!

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                            • #29
                              ok boys, settle down.

                              consider this: they're flying an aircraft designed to takeoff and fly carrying many, many tons of freight. assuming (safely) that this aircraft was empty, they certainly had plenty of wiggle room as it relates to thrust and performance in general.

                              without having the knowledge of gabriel, or the experience of ANYONE who actually flies these things in real life, i'm fairly convinced that the plane was well within the range of its performance envelope at the time.

                              having said that, if you wanna have an academic debate over whether what was done was a) legal b) wise, go ahead.

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                              • #30
                                Originally posted by Evan View Post
                                Do those "unwritten rules" apply to ferry flights or demonstration flights? Certainly test flights for certification involve things that would be considered too risky for a revenue flight.
                                Yes. What does change is:
                                - What is "necessary for the mission".
                                - The risk management process and planning.

                                I would worry that, with weight-saving as such a primary concern, airframes may not be as overbuilt as they used to be.
                                Regardless of how valid your concern might be, structural integrity was not at risk here at all (not, until we test it against the solid ground): the plane was flaying way too slow to have the "power" to damage itself from aerodynamic loads.

                                --- 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

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