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

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  • #31
    Originally posted by TeeVee View Post
    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.
    Define "performance envelope".

    Yes, they didn't lose control and the plane didn't break, so it was within it's "physical" performance. Well within? I highly doubt it but cannot prove it otherwise.

    Now, there is an operative approved envelope that says, for example, you shall not bank past 30° (what they did), and as soon as you reach 35°, a "bank angle, bank angle" alarm will sound in the cockpit. Not only that, but banks at low speed and altitudes are proceduraly more restricted than that. Yes, it's a "legal" or "procedural" limitation to the performance. But do you think that they established it just because they were too bored and had nothing better to do?

    --- 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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    • #32
      This kind of things don't need to go wrong and are not inherently unsafe, meaning that it is well within the physical possibilities of the airplane.

      ... an airline pilot who was flying a Bombardier Dash 8 carrying 24 passengers and three crewmembers intentionally flew at a very low altitude at high speed over his house and a local mall.


      That is, as long as the pilots know very VERY well what they are doing. Until sometime they make a mistake. Then we blame the stupid pilot:

      Courtesy 365 NEWSDramatic video has emerged showing the moment a plane crashed into the drag strip of a racing club in Iceland, killing two of its three occu...


      This was also VERY WELL within the airplane performance capabilities, except the part of contacting the ground, of course.

      Before you say "hey, pilots are good" question this (specifically for the case of the 747F in this thread): Do you think that your usual pilot is fully aware of the list of things I mentioned earlier in this post and the exact effect on this particular airplane, this particular day, with this particular weight and CG? DO you think that pilots cover this maneuver in type, initial LOFT or recurrent training? The answer to both questions is NO.

      And before you go back to the airshow display scenario, again, these flights are well planned in advance, with the participation of pilots and operations engineers, where all the risks are assessed before hand, where the parameters are well defined beforehand. Example:

      You will rotate at this speed, pitch up 3 deg per second until 15° nose up, climb to 200 ft, ensure that you have at least 180kts and at least +2000fpm of vertical speed, then apply 50% of left aileron until 40° of bank, then 50% right aileron until 40° of right bank, then 50% left aileron to level the wings. During the maneuver the pitch target will be 15° and there will be no "pull up" as in typical turns to try to keep the vertical speed. The maneuver will be immediately aborted if bank reaches or exceeds 45°, if the pitch departs 3° from the target, if the speed decays below 180kts, if the vertical speed decays below +1000 fpm, if there is a still shaker or any airplane vibration or "mushy controls" indicative of stall proximity, if there is any alarm other than "bank angle" or any engine or system malfunction.

      This definitions are based on close study of the airplane performance and limitations, nut just "pulled out of a hat". It may be very well trained in the simulator firs. Also there are steps taken to free the critical area from persons, airplanes and other vehicles. And the emergency services are on stand-by. And yet, it goes wrong many times more often than normal operations (don't get me started posting videos of airshow accidents). The increased risk is first accepted because there is a valid purpose for it, and then managed as well as possible.

      Again, I highly doubt that all this was done here, but can't prove it otherwise.

      Aviation safety is all about prevention, risk management, and overkill safety margins. Or do you think that the amazing safety levels reached are the result of perfect "problem free" machines and excellent pilots? No. It's DESPITE technical problems with the machines and pilot errors.

      This was my last post in this thread because no deaf is worse than that who can hear but will not listen.

      --- 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


      • #33
        Originally posted by Gabriel View Post

        Before you say "hey, pilots are good" question this (specifically for the case of the 747F in this thread): Do you think that your usual pilot is fully aware of the list of things I mentioned earlier in this post and the exact effect on this particular airplane, this particular day, with this particular weight and CG? DO you think that pilots cover this maneuver in type, initial LOFT or recurrent training? The answer to both questions is NO.


        This was my last post in this thread because no deaf is worse than that who can hear but will not listen.
        While I understand and much regret the fact that you will not be posting in this thread again due to the persistent deafness issue, I would, nevertheless, be curious to know when and/or how you became familiar with Cargolux's training program, specifically as regards what sort of unusual attitudes/maneuvers they do or don't train. Since you wrote NO in caps, I am led to believe you have some definitive knowledge on the subject.

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        • #34
          Originally posted by Gabriel View Post
          {Airshow blah blah blah}...The increased risk is first accepted because there is a valid purpose for it, and then managed as well as possible.

          Again, I highly doubt that all this was done here, but can't prove it otherwise...

          ...Deafness...
          Deafness?

          ...did you hear anything subtle on the video...

          ...like lots of camera sounds perhaps?

          For the sake of argument- this WAS an airshow.

          It's all arm chair parlour talk, but as they were running various pre-start checklists, I can just hear the pilots saying, "this departure is going to be a show, the press is there, the bosses suggested a wing wave and the chief test pilot and I were already thinking the same thing, so we all agreed to do it with robust safety margins. I plan to dip the wings twice- maybe up to 45 degrees. We're light, after we lift off, I'll pull up more slowly and build 25 extra knots of speed and then first go left and then right. We'll both watch the airspeed and attitude and stick shaker, and if we get slower than X or the shaker goes off, I'll immediately level the wings and lower the nose...

          (...but only an appropriate, carefully-measured little bit of nose-down while still maintaining a healthy climb attitude for the powerful engines, or maybe not lower the nose at all, but I'll at least think about it and not pull up relentlessly.)"

          [Insert all the other standard preflight briefing stuff]

          ..."any questions?"...

          I can't prove it either, but I bet a beer the pilots discussed the maneuver and made appropriate performance considerations before they reached the runway.

          The main reason I think this is as you say, the safety culture and outstanding safety record in aviation is, {quote=Gabe} "...all about prevention, risk management, and overkill safety margins." {/quote}

          The second reason I think it's true is that companies know that there's now weirdos with smart-phone cameras everywhere, who can't wait to capture something non-normal, slap it on YouTube and generate all sorts of snot-nosed, uninformed, over-analytical parlour talk on an obscure discussion forum somewhere.

          There's a lot of reasons for them to have done this maneuver right.
          Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

          Comment


          • #35
            I recently visited the Boeing factory. in Seattle I was told that the delivery of an aircraft is a major event, with the employees coming out to wave good by. The planes wave good by circle the airport a few times in a slow and in a dirty configuration. I didn't know that Boeing field was a regular airport and Boeing only leases one runway!

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            • #36
              Originally posted by Gabriel View Post
              That is, as long as the pilots know very VERY well what they are doing. Until sometime they make a mistake.
              Gabriel, pilots who prang airplanes ALWAYS know very well what they are doing. That IS the mistake they make.
              The investigation report into the crash was released on 13 December 2010. It blamed pilot error, stating that the pilot's overconfidence in executing an aggressive right-turn maneuver led to a low-altitude stall and subsequent crash.
              But, all's well that ends well. Until it doesn't.

              Comment


              • #37
                Safety issues aside, the maneuver was not even aesthetically pleasing. If it was the delivery departure it must have been flown by Cargolux pilots.

                Comment


                • #38
                  btw I just realized BoingBobby is probably the only person on this forum actually qualified to answer this question...is he around?

                  Comment


                  • #39
                    Originally posted by Leftseat86 View Post
                    btw I just realized BoingBobby is probably the only person on this forum actually qualified to answer this question...is he around?
                    exactly what i was thinking...

                    come on BB weigh in on this

                    Comment


                    • #40
                      Originally posted by TeeVee View Post
                      exactly what i was thinking...

                      come on BB weigh in on this

                      Sorry, actually had a real vacation with the wife for the last 2 weeks driving around Italy. Just looked this morning and saw this along with a pm from Gabriel about it. Policy at our company, no turns below 400' agl. Was this a little extreme? Maybe, was it safe? mostly. I just flew the LCF out of Boeing field last month. The runway is plenty long enough (10000') and there is not really any terrain in close proximity to the field. It is not unusual to to a little "fun" stuff when picking up a new aircraft from the delivery center. He would have been empty with enough fuel to go to Luxembourg. Not really that big of a deal.

                      Comment


                      • #41
                        Originally posted by BoeingBobby View Post
                        Sorry, actually had a real vacation with the wife for the last 2 weeks driving around Italy. Just looked this morning and saw this along with a pm from Gabriel about it. Policy at our company, no turns below 400' agl. Was this a little extreme? Maybe, was it safe? mostly. I just flew the LCF out of Boeing field last month. The runway is plenty long enough (10000') and there is not really any terrain in close proximity to the field. It is not unusual to to a little "fun" stuff when picking up a new aircraft from the delivery center. He would have been empty with enough fuel to go to Luxembourg. Not really that big of a deal.
                        Well, that's not exactly what I thought you were going to say.

                        Of course I respect your answer, not only (nor mostly) because you fly this things for a living (all the pilots that crashed with terrible airmanship were doing that for a living), but also because you've shown to be very conservative and strongly biased towards safety with your answer in all previous discussions.

                        However, this video still make me shiver and not because it "looks" a little extreme, but because there were too many things against it, even if the plane rotated a bit past Vr.

                        - The plane was not just "flying" at that speed. It was in the middle of pitching up and increasing its climb rate, which means that the load factor was more than 1, and that the AoA was greater than the one needed to fly "steadily" at that speed.
                        - The bank angle tilts your lift vector so it also increases your need of lift to have the same amount of lift in the "up direction than without a bank, This is again a higher AoA.
                        - The roll motion increases the AoA of the down-going wing, especially at the tips.
                        - The roll spoilers are still spoilers which have "spoil" in it for a reason, They spoil the airfoil and airflow, effectively stalling the zone of the wing behind them and reducing lift and increasing drag. Something not very healthy in the middle of the rotation.
                        - Swept wings have a natural tendency to stall tip first, and that is especially true when that wing is going down and you have spoilers deployed.
                        - All wings, and especially swept wings, have a natural tendency to lose roll damping at high AoA. At the same time, at high AoAs ailerons lose effectiveness and increase their adverse yaw.

                        In the videos that I posted the links, both of them swept wings jet transport, the planes crashed despite the fact that they were flying at a speed well above the nominal Vs, and in both cases they could not level the wings despite applying full aileron input to do so.

                        It is also common see airplane "wobbling" the wings when they approach the stall. The Detroit accident where MD-80 took off with no flaps/slats is a clear case where the pilot did a remarkable job at flying the plane at the onset of the stall warning, and keeping the wings level ON AVERAGE, however the loss of aileron authority and roll damping had the plane rolling from side to side (hence with the lift to pointing up all the time) and requiring the pilot to do large roll inputs (including roll spoiler inputs) that added drag and reduced lift, which undermined the performance enough to make the climb gradient too shallow and the plane impacted light poles.

                        I guess that what I mean is... Yes, it was safe, as we can see that the pilot managed to control the situation and fly away with no problem. My issue is if he was not sort of "test flying" the plane and was really aware of all of the factors that I mentioned above and took them into account and had practiced this kind of high-bank, high-roll rate, sustained full aileron command (including 5 seconds of continuous full spoiler deflections in one wing), slow speed, more increasing pitch and increasing climb rate enough times in the simulator (or at several thousand feet) before doing it for real.

                        And Boeingbobby, another question. If you are at say V2+10 established in the climb at 400 feet (pitch, speed & climb rate stable, which this plane was not) with take-off flaps, do you have any procedure limit to your bank angle or the usual 30° is ok? (and I will not even ask if you'd use full ailerons to establish the desired bank angle).

                        --- 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


                        • #42
                          I just finally watched that video on a large screen. What I find crazy is that the full left roll spoiler deflection happens the moment after lift-off, when the mains are only 15' on a 225' wingspan aircraft, and the left wingtip stays at around 50' until the roll is arrested. Are we even sure this was intentional?

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                          • #43
                            Originally posted by BoeingBobby View Post
                            Not really that big of a deal.
                            BB...

                            I can only imagine that you are still in "vacation mode" or perhaps forgot where you are posting.

                            This is the JP.net forums, where *everything* is a big deal!
                            Be alert! America needs more lerts.

                            Eric Law

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                            • #44
                              Originally posted by Evan View Post
                              Are we even sure this was intentional?
                              Surely you must know there's only one person in the world who can answer that question, and (s)he most likely is not a member of this forum...
                              Be alert! America needs more lerts.

                              Eric Law

                              Comment


                              • #45
                                How could this have been not intentional? I can't imagine a (sensible) non-intentional sequence of events that leads to what we see in the video.

                                --- 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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