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  • Seven years later and nothing has been learned?

    Jetstar A320 loses speeds at cruise and DESCENDS.

    http://avherald.com/h?article=49b0ffa9&opt=0


    The guys with the pointy heads who made the airplane and know the aerodynamics wrote a VERY SIMPLE memory procedure for this. Why has NOBODY EVER followed it?

    Why do pilots continue to improvise (wrongly)?

    Why would you EVER depart fat, dumb, happy, level flight without airspeeds?

    Do they not know that UAS is a transient thing that typically lasts one minute or less?

    Seven years after AF447, is anybody teaching pilots ANYTHING about UAS?

  • #2
    Originally posted by Evan View Post
    Jetstar A320 loses speeds at cruise and DESCENDS.

    http://avherald.com/h?article=49b0ffa9&opt=0


    The guys with the pointy heads who made the airplane and know the aerodynamics wrote a VERY SIMPLE memory procedure for this. Why has NOBODY EVER followed it?

    Why do pilots continue to improvise (wrongly)?

    Why would you EVER depart fat, dumb, happy, level flight without airspeeds?

    Do they not know that UAS is a transient thing that typically lasts one minute or less?

    Seven years after AF447, is anybody teaching pilots ANYTHING about UAS?
    [3WE's hat on] Did the pull up relentlessly? [/3WE's hat off]

    --- 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


    • #3
      Scenario:

      You encounter a flock of birds during climb and you get unreliable airspeed that you seriously suspect will be permanent.

      - AP/AT/FD: Off
      - TL: CLB
      - Picth: 10 deg ANU
      - Consult tables in the manual for fine-tuned thrust and pitch to keep level flight, in function of weight and FL.

      Next? Do the tables have pitch/thrust combos for climb and descent? What about approach and landing?

      --- 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


      • #4
        Originally posted by Gabriel View Post
        Scenario:

        You encounter a flock of birds during climb and you get unreliable airspeed that you seriously suspect will be permanent.

        - AP/AT/FD: Off
        - TL: CLB
        - Picth: 10 deg ANU
        - Consult tables in the manual for fine-tuned thrust and pitch to keep level flight, in function of weight and FL.

        Next? Do the tables have pitch/thrust combos for climb and descent? What about approach and landing?
        Climb or descend with unreliable airspeeds? You level off, stabilize, ride it out. Then, when the speeds come back, you go back to whatever you were doing.

        Of course, if you hit something that permanently damages the pitots, that's a different story. Like landing on the Hudson, the procedure is: use your head.

        Comment


        • #5
          Originally posted by Evan View Post
          Jetstar A320 loses speeds at cruise and DESCENDS.

          http://avherald.com/h?article=49b0ffa9&opt=0


          The guys with the pointy heads who made the airplane and know the aerodynamics wrote a VERY SIMPLE memory procedure for this. Why has NOBODY EVER followed it?
          Seriously? Can you produce documentation proving that nobody has ever followed a UAS procedure?

          Originally posted by Evan View Post
          Why do pilots continue to improvise (wrongly)?
          Because they're trained to fly airplanes and not just blindly follow a list of instructions like a 6-year-old? Granted that's becoming less true as time goes on but still...

          And here's another answer to that same question: unlike the pointy-head guys, the pilots in question are present in the aircraft at the time the situation is taking place. That means a) their lives may well depend on the right decision being made and b) they are aware of the specific circumstances of their situation, not the hypothetical situation the checklist was meant to cover. See next item for more info...

          Originally posted by Evan View Post
          Why would you EVER depart fat, dumb, happy, level flight without airspeeds?
          Just a couple of examples: the aircraft is on fire. Or it's about to run out of fuel. Or you're flying fat, dumb, happy, and level at an altitude lower than the top of the mountain that's in front of you.

          Originally posted by Evan View Post
          Do they not know that UAS is a transient thing that typically lasts one minute or less?
          There is a reason "typically" and "always" are separate words in the dictionary...
          Be alert! America needs more lerts.

          Eric Law

          Comment


          • #6
            Originally posted by Evan View Post
            Jetstar A320 loses speeds at cruise and DESCENDS.

            http://avherald.com/h?article=49b0ffa9&opt=0


            The guys with the pointy heads who made the airplane and know the aerodynamics wrote a VERY SIMPLE memory procedure for this. Why has NOBODY EVER followed it?

            Why do pilots continue to improvise (wrongly)?

            Why would you EVER depart fat, dumb, happy, level flight without airspeeds?

            Do they not know that UAS is a transient thing that typically lasts one minute or less?

            Seven years after AF447, is anybody teaching pilots ANYTHING about UAS?
            I don't see a problem here, and here is why:

            Let's recall what the memory item opens with. The top of the page states "If the safety of flight is impacted". If yes, then we play the whole 15/TOGA, 10/CLB, 5/CLB game.

            At FL370 the safety of flight is NOT immediately impacted (just like it wasn't with AF447). However, depending on the weight and the temp, their buffet margins were likely fairly narrow. With the loss of indicators, they also could no longer trust the barber pole and the tiger tail. Thus, they likely decided to proceed lower where:

            1. Said margins are considerably wider;

            2. Temperatures are warmer, so the tubes would unfreeze quicker (provided they were, in fact, frozen).

            Seems to me they properly relied on their remaining instruments, got the airplane into denser air and proceeded on their merry way. I'd buy them each a cup of Fourbucks.

            Comment


            • #7
              Originally posted by ATLcrew View Post
              Seems to me they properly relied on their remaining instruments, got the airplane into denser air and proceeded on their merry way. I'd buy them each a cup of Fourbucks.
              And this is what I mean by not learning anything in seven years. Yes, these pilots pulled off successfully a maneuver that could have gone very wrong with a less adept (or less lucky) crew. So what's the problem?
              Just like AF447, where many pilots had ignored procedure and relied on their improvised airmanship (in some cases resulting in a very white knuckle moment), sooner or later a poorly trained crew is going to do that and kill everyone on board. It's only a matter of time.

              vs

              You lose airspeeds: you STABILIZE the airplane WITHIN THE ENVELOPE using pitch and power settings established scientifically by the people who spent a decade in the wind tunnel designing it. This way, nobody, no matter how adept or inadept, every stalls or overspeeds.

              Departing flight level without airspeeds is departing stabilized flight. Not too clever actually.

              Comment


              • #8
                Airbus pilots are defending this crew's actions, saying that it is known from their training that, at high altitude, 0 deg pitch and idle thrust gives them a stable descent, within the envelope (no stall, no overspeed), providing a path towards a lower altitude with a bigger margin between stall and overspeed.

                I cannot say that it is wrong. They descend everyday from cruise. Every flight has this phase. If 0 deg and idle works with airspeed indicators operative, it also does so with UAS. Newton, Navier, Stokes and Bernoulli don't know what care what the ASI are or aren't indicating.

                --- 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


                • #9
                  Originally posted by Gabriel View Post
                  Airbus pilots are defending this crew's actions, saying that it is known from their training that, at high altitude, 0 deg pitch and idle thrust gives them a stable descent, within the envelope (no stall, no overspeed), providing a path towards a lower altitude with a bigger margin between stall and overspeed.

                  I cannot say that it is wrong. They descend everyday from cruise. Every flight has this phase. If 0 deg and idle works with airspeed indicators operative, it also does so with UAS. Newton, Navier, Stokes and Bernoulli don't know what care what the ASI are or aren't indicating.
                  If that is true and reliable, then make it an operator approved procedure and train pilots on it. I can see it done wrong... sooner or later... if it is left to improvisation.

                  Also, these ITCZ events tend to happen in close proximity to convective weather systems that launch those ice crystals into the upper atmosphere. If you are descending into nice, stable air, then maybe this works, but if you are descending into potential turbulence or windshear I can see it ending badly.

                  But the thing is, in all of those events recorded prior to AF447, the speeds came back in about a minute, so why descend at all?

                  And one more important thing not to be forgotten here: you are now descending without speeds AND without protections...

                  Comment


                  • #10
                    Originally posted by Evan View Post
                    If that is true and reliable, then make it an operator approved procedure and train pilots on it. I can see it done wrong... sooner or later... if it is left to improvisation.

                    Also, these ITCZ events tend to happen in close proximity to convective weather systems that launch those ice crystals into the upper atmosphere. If you are descending into nice, stable air, then maybe this works, but if you are descending into potential turbulence or windshear I can see it ending badly.

                    But the thing is, in all of those events recorded prior to AF447, the speeds came back in about a minute, so why descend at all?

                    And one more important thing not to be forgotten here: you are now descending without speeds AND without protections...
                    A few things:

                    1. The report doesn't actually say they didn't perform the memory items prior to the descent, it only says that they descended at some point after the malfunction. So, for all "we" know, they ran the memory items (even though according to the manufacturer-approved procedure they weren't required in this case), then descended. "We" also don't know how long it was before they descended. If the AS didn't come back after your "magic minute", how much longer would you have them wait?

                    2. You may be surprised (nay, shocked) to hear that there IS in fact true and reliable operator-approved procedure for descent with unreliable airspeed. In fact, there is a whole series of charts in the QRH on thrust and pitch settings for climb, cruise and descent with unreliable airspeed. In fact, after you run the memory items, you will be directed to those very charts. You do have a copy of the QRH, do you not? So, yes, the procedure exists and it IS trained.

                    And one more thing not to be forgotten here: between descending with no AS and no protections and staying at FL370 with no airspeed and no protection, I know which one I'll pick.

                    Comment


                    • #11
                      Originally posted by ATLcrew View Post
                      A few things:

                      1. The report doesn't actually say they didn't perform the memory items prior to the descent, it only says that they descended at some point after the malfunction. So, for all "we" know, they ran the memory items (even though according to the manufacturer-approved procedure they weren't required in this case), then descended. "We" also don't know how long it was before they descended. If the AS didn't come back after your "magic minute", how much longer would you have them wait?

                      2. You may be surprised (nay, shocked) to hear that there IS in fact true and reliable operator-approved procedure for descent with unreliable airspeed. In fact, there is a whole series of charts in the QRH on thrust and pitch settings for climb, cruise and descent with unreliable airspeed. In fact, after you run the memory items, you will be directed to those very charts. You do have a copy of the QRH, do you not? So, yes, the procedure exists and it IS trained.

                      And one more thing not to be forgotten here: between descending with no AS and no protections and staying at FL370 with no airspeed and no protection, I know which one I'll pick.
                      Ok, fair enough. If they FIRST stabilized in level flight and then got into the descent using the QRH values and they were not descending into anything threatening then I suppose this is probably safe enough. But the AV Herald report makes no mention of that.

                      Yes, I'm aware of the QRH charts for climb and descent with UAS. I see these as useful for pitot damage or other PERMANENT airspeed data issues, where obviously you have to complete the flight without speeds. With these TRANSIENT upper atmospheric speed loss issues, however, I don't see the wisdom in descending into warmer air where ice is more likely to be a problem and UAS is more common.

                      My impression was that they REACTED by descending, which would be inherently risky. We may never know.

                      Comment


                      • #12
                        Originally posted by Evan View Post
                        My impression was that they REACTED by descending, which would be inherently risky. We may never know.
                        you mean your 2 dimensional thinking, right? evan's way or no way.

                        perhaps you should read other fora where there tend to be more professional pilots that have been discussing this topic for YEARS. no disrespect to those pilots on this board, but maybe, just maybe, evan will learn from a much larger group of these folks, since all he ever seems to do here is argue with you guys.

                        Comment


                        • #13
                          Not gonna pretend to be smart here. Too risky. But since the premise seems to be "pilots are improvising", does that imply they did other than what they were trained to do? I mean, if they were simply following training, that seems like a big improvement over what I read in the discussion here about AF447 where at least a few here said the pilots did NOT do what pilots are trained to do.

                          Comment


                          • #14
                            Originally posted by Gabriel View Post
                            [3WE's hat on] Did the pull up relentlessly? [/3WE's hat off]
                            I usually apply that to instances where the loss of altitude seems unintended followed by other undesirable outcomes like engine flameouts, and, in-particular, large-magnitidue, wallowing descents to bad landings.

                            Originally posted by Evan
                            You lose airspeeds: you STABILIZE the airplane WITHIN THE ENVELOPE using pitch and power settings established scientifically by the people who spent a decade in the wind tunnel designing it.
                            1. Is there evidence that the plane was not_stabilized in a reasonably fat, dumb and happy envelope?

                            2. Wait a second, I thought using known power and pitch settings was a major trigger for an Evan rant on what not_to do when you don't know your airspeed?

                            PS, I see the little Evan-World comment that only engineers can scientifically establish them, because operating a plane for a few thousand hours (with some perfectly valid, scientific, large-n, observations by the idiot pilots (along with reading the book once or twice) doesn't count for anything at all whatsoever.

                            Originally posted by elaw
                            There is a reason "typically" and "always" are separate words in the dictionary...
                            Careful, you're getting into the realm of logic...

                            Originally posted by AirbusCrew&Worshiper
                            I don't see a problem here...
                            I tend to agree with your assessment and know you will be glad to hear that.
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                            Comment


                            • #15
                              Originally posted by EconomyClass View Post
                              Not gonna pretend to be smart here. Too risky. But since the premise seems to be "pilots are improvising", does that imply they did other than what they were trained to do? I mean, if they were simply following training, that seems like a big improvement over what I read in the discussion here about AF447 where at least a few here said the pilots did NOT do what pilots are trained to do.
                              The AF447 pilots WERE NOT TRAINED to do anything, that was and still is the problem. Hopefully this is not true of JetStar.

                              Originally posted by 3WE
                              2. Wait a second, I thought using known power and pitch settings was a major trigger for an Evan rant on what not_to do when you don't know your airspeed?
                              MEMORIZED pitch and power settings. Not IMPROVISED pitch and power settings. That is to stabilize. Again, if this crew did that first and then descended using pitch and power settings established by airbus engineers, then I am not nearly as concerned. But I still question of the wisdom of the descent (question, as in, I would llike to know more details about the incident, which hopefully will be released some day soon).

                              On the other hand, if they simply reacted by descending without first stabilizing and consulting the QRH (or having the safe pitch setting memorized), I am very concerned.

                              Comment

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