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Lion Air 737-Max missing, presumed down in the sea near CGK (Jakarta)

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  • Originally posted by Gabriel View Post
    Once again, I disagree. Or more precisely, I agree with what you say but it is not enough to explain what happened.
    Say that in the office where you work one day they build a new wall in a place you usually walked through. Would you just walk into the wall that is there in plain sight, and that you do see it, and then blame that there was no memo informing of the new wall and that you were not properly trained in wall avoidance?
    Ok, let's run with that analogy, but fix it. Say that in the office where you work one day they build a new wall in a place you've never walked through before. It wouldn't make any difference. You'd just be lost anyway.

    How often do NG pilots get a runaway trim encounter that requires them to cut off the stab trim to regain control? I'm guessing these pilots had never encountered that. I'm also guessing they had never encountered training for that.

    ...and when the nose did go down and pulling up didn't fix it they thought that they were still in a stall and decided to not to make more nose-up trim inputs (but then why they kept pulling up as hard as they could?)
    Elapsed time: about five seconds. In those five seconds, with scrambled situational awareness and probably panic taking over, they didn't go to the pitch trim. It's happened before. It should be expected to happen.

    The key to avoiding these kinds of accidents is to avoid putting pilots in these kinds of situations. Nothing else is going to reliably work.

    Solid training on runaway trim procedure would have avoided this situation.

    Comment


    • Originally posted by Evan View Post
      The key to avoiding these kinds of accidents is to avoid putting pilots in these kinds of situations.
      So maybe no pilots in the cockpit at all?

      Comment


      • Originally posted by Evan View Post
        Ok, let's run with that analogy, but fix it. Say that in the office where you work one day they build a new wall in a place you've never walked through before. It wouldn't make any difference. You'd just be lost anyway.
        You mean these pilots never encountered nose-down tendency that required nose-up trim to avoid keep pulling back on the yoke? Actually they did, the last 12 minutes or so before the loss of control.

        How often do NG pilots get a runaway trim encounter that requires them to cut off the stab trim to regain control? I'm guessing these pilots had never encountered that.
        Your guess is probably right for that and about every emergency and abnormal situation. Most pilots never encounter engine failures at V1, engine fires, rapid depressurization, UAS, flaps disagree, severe windshear that requires evasive action, ur severe upset that requires upset recovery techniques... or trim runaway.
        I'm also guessing they had never encountered training for that.
        I hope but also guess that you'd be wrong with that guess.
        The key to avoiding these kinds of accidents is to avoid putting pilots in these kinds of situations. Nothing else is going to reliably work.

        Solid training on runaway trim procedure would have avoided this situation.
        Well, a more sound MCAS logic on disagreeing AoA (or a 3rd AoA vane, or a third AoA calculated based on other flight parameters like speed, weight and Gs) would have been helpful too. And more in line with "avoid putting pilots in these kinds of situations".

        --- 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


        • Originally posted by BoeingBobby View Post
          So maybe no pilots in the cockpit at all?
          My preference in the following order:

          1 - Extensively trained, experienced pilots

          2 - No pilots

          3 - Poorly trained, poorly chosen pilots.

          Comment


          • Originally posted by Gabriel View Post
            You mean these pilots never encountered nose-down tendency that required nose-up trim to avoid keep pulling back on the yoke? Actually they did, the last 12 minutes or so before the loss of control.
            I mean they probably never encountered a stealthy runaway trim situation, where the only real fix is to cut off the electric trim, and probably never used the trim cutout switches before.

            Well, a more sound MCAS logic on disagreeing AoA (or a 3rd AoA vane, or a third AoA calculated based on other flight parameters like speed, weight and Gs) would have been helpful too. And more in line with "avoid putting pilots in these kinds of situations".
            Indeed, but I was speaking more generally. Everything must be done to avoid placing pilots in disorienting, panic-prone situations, because once they get there they often don't come back.

            Comment


            • Originally posted by Evan View Post
              Everything must be done to avoid placing pilots in disorienting, panic-prone situations, because once they get there they often don't come back.
              Well...OK, then.
              Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

              Comment


              • Originally posted by BoeingBobby View Post
                So maybe no pilots in the cockpit at all?
                Do you use a West Bend, cheap composite, Stir Crazy popcorn popper with automatic heat control?

                OR

                A pot on a stove?

                OR

                A hot air popper?
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • Front page story on the New York Times today. It includes this revelation:

                  Originally posted by NY Times
                  In the older [737] versions, pilots could help address the problem of the nose being forced down improperly — a situation known as “runaway stabilizer trim” — by pulling back on the control column in front of them, the pilots say.
                  In the latest 737 generation, called the Max, that measure does not work, they said, citing information they have received since the crash.
                  Originally posted by Gabriel View Post
                  Why on Earth would the pilots do that? Why would they stop adding enough nose-up trim?
                  I think I might have found the answer to that one:

                  Originally posted by NY Times
                  The pilot had handed control of the plane to the co-pilot just before the plane went into its final dive.

                  Comment


                  • At this point there seems general agreement that the pilots screwed the pooch but I go back to my original point/post which is that a test flight should have been conducted given the circumstances. I've read on av-herald both a mechanic and pilot saying the plane should have been rejected to being returned to service given the circumstances. (For me, "test flight" and "rejected to return to service" are synonymous.)

                    It seems to me, as a lowly passenger, we're being asked to be guinea pigs with insufficient knowledge of the circumstances, at the mercy purely of the pilots skills, thereby eliminating a ginormous mountain of potentially mitigating safeguards. As I said before, if you give me Sulley or Boeing Bobby or Neil freaking Armstrong, I'll buckle up and take my chances, and same for a nearly brand new properly functioning plane with pilot(s) I assume are competent. But a "who knows?" pilot with an aircraft coming off a serious maintenance event? Very few people would sign up for that and rightfully so.

                    Comment


                    • In the older [737] versions, pilots could help address the problem of the nose being forced down improperly — a situation known as “runaway stabilizer trim” — by pulling back on the control column in front of them, the pilots say.
                      In the latest 737 generation, called the Max, that measure does not work, they said, citing information they have received since the crash.
                      I don't know, but I very much doubt it.

                      --- 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


                      • Originally posted by Chris K View Post
                        At this point there seems general agreement that the pilots screwed the pooch but I go back to my original point/post which is that a test flight should have been conducted given the circumstances. I've read on av-herald both a mechanic and pilot saying the plane should have been rejected to being returned to service given the circumstances. (For me, "test flight" and "rejected to return to service" are synonymous.)
                        You have a strange sense of semantics.

                        It seems to me, as a lowly passenger, we're being asked to be guinea pigs with insufficient knowledge of the circumstances, at the mercy purely of the pilots skills, thereby eliminating a ginormous mountain of potentially mitigating safeguards. As I said before, if you give me Sulley or Boeing Bobby or Neil freaking Armstrong, I'll buckle up and take my chances, and same for a nearly brand new properly functioning plane with pilot(s) I assume are competent. But a "who knows?" pilot with an aircraft coming off a serious maintenance event? Very few people would sign up for that and rightfully so.
                        Probably that's why in Europe and USA, where flight crews have a tendency to properly report issues and maintenance have a tendency to properly fix them, almost NEVER there is a death in a commercial flight, and that's out of millions of flights per year and hundreds of millions of pax per year. And in case I am not making myself clear, that almost never involves test flights.

                        --- 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


                        • Originally posted by Gabriel View Post
                          You have a strange sense of semantics.

                          Probably that's why in Europe and USA, where flight crews have a tendency to properly report issues and maintenance have a tendency to properly fix them, almost NEVER there is a death in a commercial flight, and that's out of millions of flights per year and hundreds of millions of pax per year. And in case I am not making myself clear, that almost never involves test flights.
                          Yes -- "almost" being the key word. Semantics indeed ....

                          Comment


                          • Originally posted by Chris K View Post
                            Yes -- "almost" being the key word. Semantics indeed ....
                            So what do you expect? Never ever a death? Is that a reasonable expectation?

                            --- 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


                            • Originally posted by Chris K View Post
                              It seems to me, as a lowly passenger, we're being asked to be guinea pigs with insufficient knowledge of the circumstances, at the mercy purely of the pilots skills, thereby eliminating a ginormous mountain of potentially mitigating safeguards.
                              The decision to be a guinea pig is yours to make. You want to fly on a corner-cutting Indonesian airline with an atrocious safety record, climb aboard, Mr. Guinea Pig.

                              Airlines with a proper safety culture, under the watchful eye of civil aviation authorities with a proper safety culture, ensure that their pilots and maintenance personnel are familiar with the procedures that prevent lowly passengers from ending up as dead guinea pigs. Most of that never requires test flights. Just proper ground tests.

                              It appears that the AoA vane here didn't fail due to a mechanical issue that would have only been revealed in flight, so it must have been either installed incorrectly, miscalibrated or something was off in the logic. Any of those things could have be detected on the ground, if, of course, anyone bothered to check these things properly.

                              Comment


                              • Originally posted by Evan View Post
                                Airlines with a proper safety culture, under the watchful eye of civil aviation authorities with a proper safety culture, ensure that their pilots and maintenance personnel are familiar with the procedures that prevent lowly passengers from ending up as dead guinea pigs.
                                And yet again I ask which airlines and "watchful authorities" do you mean? You did let now-defunct Air Berlin slip out in one post, which I still don't find credible.

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