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

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  • Hello all! I'm glad there is a thread on this. I read the entire 322 page crash report and found a few things interesting I thought I would share.

    There were four main factors in the crash.

    1) Design Flaw (MCAS)
    2) Pilot Error
    3) Failure to Complete Maintenance-
    The report states that Lion Air failed to maintain an airworthy aircraft. There were known issues with the AOA sensors that were never addressed or fixed. These problems persisted for several flights leading up to the accident flight.
    4) Improper Maintenance Procedures-
    Lion Air outsourced their minimal maintenance done on the original problems with the AOA sensors to a third party company. This company implemented unapproved procedures and installed uncertified parts in order to "fix" the AOA sensors. This fix was nullified almost immediately as the repaired sensors quickly failed again. With the sensors failing again, as stated in #3, Lion Air neglected to put the aircraft in maintenance to fix the problem. Instead, flying a plane with paying passengers that was not airworthy.

    Comment


    • Originally posted by Cleveland.Spotter View Post
      Hello all! I'm glad there is a thread on this. I read the entire 322 page crash report and found a few things interesting I thought I would share.

      There were four main factors in the crash.

      1) Design Flaw (MCAS)
      2) Pilot Error
      3) Failure to Complete Maintenance-
      The report states that Lion Air failed to maintain an airworthy aircraft. There were known issues with the AOA sensors that were never addressed or fixed. These problems persisted for several flights leading up to the accident flight.
      4) Improper Maintenance Procedures-
      Lion Air outsourced their minimal maintenance done on the original problems with the AOA sensors to a third party company. This company implemented unapproved procedures and installed uncertified parts in order to "fix" the AOA sensors. This fix was nullified almost immediately as the repaired sensors quickly failed again. With the sensors failing again, as stated in #3, Lion Air neglected to put the aircraft in maintenance to fix the problem. Instead, flying a plane with paying passengers that was not airworthy.
      Noted.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • Originally posted by Cleveland.Spotter View Post
        Hello all! I'm glad there is a thread on this. I read the entire 322 page crash report and found a few things interesting I thought I would share.

        There were four main factors in the crash.

        1) Design Flaw (MCAS)
        2) Pilot Error
        3) Failure to Complete Maintenance-
        The report states that Lion Air failed to maintain an airworthy aircraft. There were known issues with the AOA sensors that were never addressed or fixed. These problems persisted for several flights leading up to the accident flight.
        4) Improper Maintenance Procedures-
        Lion Air outsourced their minimal maintenance done on the original problems with the AOA sensors to a third party company. This company implemented unapproved procedures and installed uncertified parts in order to "fix" the AOA sensors. This fix was nullified almost immediately as the repaired sensors quickly failed again. With the sensors failing again, as stated in #3, Lion Air neglected to put the aircraft in maintenance to fix the problem. Instead, flying a plane with paying passengers that was not airworthy.
        If the passengers were not paying, would it have been okay?

        Comment


        • Originally posted by Gabriel View Post
          Even the NTSC's report on Lion AIr's accident (which is being praised by the industry at great) is ambiguous on the matter:
          It certainly isn’t ambiguous on what matters here: it was needed and is needed to certify the aircraft as safe to operate in commercial aviation. Yet one, not so unforeseeable, single sensor failure removes it from functioning. And that’s ok?

          Comment


          • Originally posted by Evan View Post
            Yet one, not so unforeseeable, single sensor failure removes it from functioning. And that’s ok?
            Why single?

            --- 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
              Why single?
              What is the probability of a double AoA vane failure?

              Comment


              • There is another possibility here. An AoA sensor disagree might be resolved by voting against the IR data, with the system choosing the a vane closest in alignment. If that works, the system could remain functional with a single vane. I wonder about that though, as a single degree of error can make a big difference where MCAS is designed to operate.

                Comment


                • Originally posted by Schwartz View Post
                  Defend at all costs, please. Instead of waxing poetic why don't you point out the flaw in the logic? Or is that just rhetoric?
                  The flaw in whose logic? I've been waiting to read real arguments from the likes of BoeingBobby, but instead I see mostly jabs and attacks at anyone who points out the seriousness of the MCAS mess and how it relates to the two MAX crashes. And in my book, this is flawed logic - saying ambiguous stuff about the author of a post instead of constructing an argument that debates what is being said in the post.

                  Comment


                  • Originally posted by Schwartz View Post
                    That logic is predicated on MCAS being considered an essential safety system (vs a safety hazzard as it clearly was initially implemented). I have a feeling it is not considered such. I believe it was added to make it feel more like the old models. More sensors increases the odds of a failure and depending on the nature of typical failures for this type of sensor, perhaps it isn't all that unlikely that 2 fail close together.
                    I think as it stands now, MCAS was needed for certification. We can debate how essential the system is (or was), but the 737 MAX was certified as just another 737, for which it needed to feel just like the old 737 models. That new training you mentioned that you expect to see implemented - the lack of such training was a main selling point of this airplane. And to be able to be certified without such training, MCAS was needed for safety. So it would seem pretty essential when it comes to safety, unless the training is changed, which changes the acquisition/operation costs for the airlines.

                    Now I don't see how more sensors leads to a system that is more prone to failure. More sensors equals more redundancy, and having redundant systems has been the safety standard in aviation for a long time, as opposed to having systems with only single components. Whether more sensors leads to more failure can be determined by studying different airplanes and comparing the frequency of failures they experience. You have planes with 2 AoAs, with 3 AoAs and with 4 AoAs. And I was also saying 2 is insufficient for redundancy. Having a system with 2 AoAs designed in a way that the system can just act upon wrong data when one of those two AoAs has failed is straight criminal in my book.

                    Comment


                    • Originally posted by Black Ram View Post
                      The flaw in whose logic? I've been waiting to read real arguments from the likes of BoeingBobby, but instead I see mostly jabs and attacks at anyone who points out the seriousness of the MCAS mess and how it relates to the two MAX crashes. And in my book, this is flawed logic - saying ambiguous stuff about the author of a post instead of constructing an argument that debates what is being said in the post.
                      Welcome to the internet in general and to aviation fora specifically.

                      Comment


                      • Originally posted by Black Ram View Post
                        I think as it stands now, MCAS was needed for certification. We can debate how essential the system is (or was), but the 737 MAX was certified as just another 737, for which it needed to feel just like the old 737 models. That new training you mentioned that you expect to see implemented - the lack of such training was a main selling point of this airplane.
                        I don't think that was the MAIN selling point of the airplane, but carry on.

                        Comment


                        • Originally posted by ATLcrew View Post
                          I don't think that was the MAIN selling point of the airplane, but carry on.
                          The main selling point of the -MAX was “Whoa... wait! Don’t buy the A320NEO! We can get those LEAP engines on the same airplane you are already using (somehow).” It was fleet commonality and deep discounts. I see cockpit commonality as part of fleet commonality. Not having to type-transition pilots was part of that selling point.

                          Seriously, with acquisition and operating costs being essentially the same, why else would you choose the 737-MAX over the A320NEO?

                          Comment


                          • Originally posted by Black Ram View Post
                            The flaw in whose logic? I've been waiting to read real arguments from the likes of BoeingBobby, but instead I see mostly jabs and attacks at anyone who points out the seriousness of the MCAS mess and how it relates to the two MAX crashes. And in my book, this is flawed logic - saying ambiguous stuff about the author of a post instead of constructing an argument that debates what is being said in the post.
                            Read my original post. A: 2 switches. B: You did not see either of the two accidents happen in the US or Canadian, European country. C: Did Boeing f**k up? Yes, but you still have to know your aircraft and how to fly by hand. Evan wants every aircraft flying passengers to have so many redundant systems that they can only carry 5 pax with their bags.

                            Comment


                            • Originally posted by BoeingBobby View Post
                              Read my original post. A: 2 switches. B: You did not see either of the two accidents happen in the US or Canadian, European country. C: Did Boeing f**k up? Yes, but you still have to know your aircraft and how to fly by hand. D: Evan wants every aircraft flying passengers to have so many redundant systems that they can only carry 5 pax with their bags.
                              A: Agree.
                              B: I tend to agree. However, I don't know of any MCAS runaway happening in one of those countries. This is in part good: These countries also tend to have much better maintenance, which was a critical factor in Lin Air (however it doesn't seem to have been an issue in Ethiopian where the AoA sensor was working ok until they rotated the plane for take-off and then it suddenly failed, presumably because of an impact). The only other case of MCAS runaway was the Lion Air flight previous to the accident flight where, with the help of a 3rd pilot that was jumpseatting, they eventually used the 2 switches that you mentioned in point A and started using the manual wheel for trim. And they still performed horribly (but survived). I would love to know of other instances of this case of MCAS incidents elsewhere.
                              C: Agree and agree.
                              D: For Evan's ideal solution, you need to add hardware and hence wight. But, as a side note, for the solution that Boeing is certifying now, no additional piece of hardware being added. Just software which doesn't weight at all.

                              --- 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
                                If the passengers were not paying, would it have been okay?
                                No, but maybe a little less insulting...sort of sucks to pay good money to get killed.
                                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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