Announcement

Collapse
No announcement yet.

Breaking news: Ethiopian Airlines flight has crashed on way to Nairobi

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by TeeVee View Post
    ok, i'll chime in....

    sorry BB, i ain't buying that this was simply shit happens. boeing engineers are far too good (for the most part) for them to be at fault (except for not blowing every fucking whistle in the universe BEFORE 300+ people died).

    on the other hand, boeing execs are just whores for wall street. safety is not their primary nor secondary concern. only stock price and making or exceeding projected profits. it is they who are truly to blame.

    the blame i lay at the feet of the engineers is their silence. and insofar as they likely could have prevented these two tragedies, are equally to blame.
    You know things are getting serious when lawyers start throwing words like "insofar" around.

    Comment


    • Originally posted by Gabriel View Post
      All airplanes with underslung engines have this "feature". It actually happened in Boeing and Airbus planes in the past, before there was a thing called MAX. That's why the stall procedure calls for reducing thrust (to my dismay, since I would prefer to manually add nose-don trim if up to full nose-down elevator is not enough).
      Boeing is, of course, playing this card close to the vest, so I can't find an entirely detailed description, but apparently the problem with the -MAX is an aerodynamic one. It goes beyond the normal pitch-thrust coupling issue because the size/shape/placement of the engine nacelles create additional lift in a way that results in an upward pitching moment at high angles of attack (and I think particularly at higher weights). I'll leave it to you to try to form a theory as to why. Hopefully the next report will go into some detail about this. But the short of it is, this was apparently an aerodynamic issue that exacerbated the pitching moment that the NG would have experienced and the powers that be felt it was unsafe without some mitigating solution.

      The new MCAS will only engage when the two AoA sensors are within 5.5° of disagreement, it will only command a single actuation of the stabilizer and the amount of stabilizer input will not exceed manual trim pilot force expectations. So that should solve the erroneous activation problem.

      However, if there is a bad AoA vane input, the MCAS system will be inoperative and the aircraft will revert to its vulnerable state at high angles of attack. So the next crash we see might involve a combination of a failed AoA sensor and pilot error combined with the aerodynamic pitching effects of the aircraft resulting in a stall.

      Boeing never should have gotten themselves into this awkward patchwork problem. Now it's just about trading one threat scenario for another (albeit more remote) one.

      Comment


      • Originally posted by Gabriel View Post
        Blah blah blah single source of information blah blah failure modes blah blah OBVIOUS.
        We may never know what folks were thinking. Perhaps they thought it was a simple push over augmentation for stallish scenarios with several robust override mechanisms?

        Who doesn't like a little push over if you're stalling and who's going to just sit there while the plane trims itself into a dive?

        In hindsight, sure, but there is that insidious Swiss cheese that may not have been obvious early on.
        Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • Originally posted by 3WE View Post
          We may never know what folks were thinking. Perhaps they thought it was a simple push over augmentation for stallish scenarios with several robust override mechanisms?

          Who doesn't like a little push over if you're stalling and who's going to just sit there while the plane trims itself into a dive?

          In hindsight, sure, but there is that insidious Swiss cheese that may not have been obvious early on.
          Again, that's the point: I don't think so. This is too basic and too obvious. Boeing is better than not realizing this.

          --- 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
            I don't think so. This is too basic and too obvious.
            Noted.

            I doubt we will ever know.
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

            Comment


            • Originally posted by 3WE View Post

              In hindsight, sure, but there is that insidious Swiss cheese that may not have been obvious early on.
              The swiss cheese model applied to a single point of failure:

              Click image for larger version

Name:	08978be42c8a996bff30f2918b3aeb13.jpg
Views:	1
Size:	11.1 KB
ID:	1035355

              Comment


              • Originally posted by Fear_of_Flying View Post
                The swiss cheese model applied to a single point of failure:
                I totally agree that there's some painfully lacking redundancy...

                HOWEVER

                this is NOT a single point of failure. It has numerous layers of swiss cheese.

                It needs:
                -AOA failure
                -Pilots totally forget the way most pilots adjust trim during 99% of their hand flying
                -Pilots not noticing (or not responding to) big-ass, noisy trim wheel zooming along in the nose-down direction.
                -Pilots, after 15 min suddenly deciding to LET the plane trim into full nose down (Lion Air)
                -Pilots too slow to hit Bobby's cut off switches.
                -To happen at the worst possible time
                -Needs to happen to pilots who lack confidence that their power and attitude are healthy
                -Needs to run long enough to get the trim wheel mechanically friction locked
                -Needs to trigger an airspeed uncertainty

                As much as I don't like the design (especially when Gabriel trashes it), I think there may be a valid argument that the plane probably would not have crashed if Boeing Bobby or maybe even one of us over-pontificating-PPL-amateurs was flying...

                On the one hand, you can argue that it was a crash waiting to happen; however, I think you need a semi-rare dual mental brain lock to crash (NO CREW ADMONISHMENT INTENDED- I give myself 70:30 odds if Gabriel was flying- I'll let him give my value)
                Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                Comment


                • And the bad hits just keep coming:

                  For the second time in two weeks, Boeing has been named in a wrongful termination lawsuit filed by a former employee at the company’s plant in North Charleston.


                  NORTH CHARLESTON, S.C. (WCSC) - For the second time in two weeks, Boeing has been named in a wrongful termination lawsuit filed by a former employee at the company’s plant in North Charleston....

                  Hollensteiner protested the practice of the alleged parties but participated in fear of losing his job, according to the lawsuit. The lawsuit details one incident in which Hollensteiner claims a senior manager told him, “Kurt, I need you to get these stamps back into compliance" which he claims the manager knew was a violation of FAA compliance.

                  That same manager would later fire Hollensteiner for falsifying company records, according to the lawsuit. Hollensteiner claims he was fired for his safety complaints regarding tool accountability and involvement in the union.

                  He is seeking actual, compensatory and punitive damages.

                  Hollensteiner becomes the third former flight line worker at the North Charleston plant to sue Boeing in 2019, joining Rich Mester and Liam Wallis.

                  Comment


                  • Was watching the Weather Channel yesterday which regularly have plane crash shows on which are pretty good. Anyway I was somewhat thunderstruck to watch a show about Scandinavian Airlines Flight 751 as there seems to have been a very comparable issue as with the MAX and MCAS.

                    While not a direct cause of the accident, the fact that the crew was insufficiently knowledgeable in how to handle engine surging due to an unknown (to them) feature of the aircraft seems like deja-vu-all-over-again:

                    "Another contribution to the accident was insufficient training of the crew: they were not trained in restoring engine operation after they repeatedly surged. There was no simulator or other training on the engine surging problem. Secondly, they were not informed about a pre-installed automatic thrust system (Automatic Thrust Restoration or ATR). The reason for this lapse of information was that there was no knowledge of ATR within SAS. However, ATR was described in manuals by the aircraft manufacturer which every operator is obliged to know. Even though the system was developed for use in procedures not applied by SAS, a sufficiently careful study of the manuals should have led to SAS noting the system and training its pilots in its function."

                    Full Wiki on the accident is at:



                    I guess this bolsters my confidence that the MAX issues can be resolved since obviously the MD-81 and its off-spring survived quite successfully after this accident (although admittedly there were no casualties in this one which is amazing in and of itself).

                    Chris

                    Comment


                    • Originally posted by Chris K View Post
                      Was watching the Weather Channel yesterday which regularly have plane crash shows on which are pretty good. Anyway I was somewhat thunderstruck to watch a show about Scandinavian Airlines Flight 751 as there seems to have been a very comparable issue as with the MAX and MCAS.

                      While not a direct cause of the accident, the fact that the crew was insufficiently knowledgeable in how to handle engine surging due to an unknown (to them) feature of the aircraft seems like deja-vu-all-over-again:

                      "Another contribution to the accident was insufficient training of the crew: they were not trained in restoring engine operation after they repeatedly surged. There was no simulator or other training on the engine surging problem. Secondly, they were not informed about a pre-installed automatic thrust system (Automatic Thrust Restoration or ATR). The reason for this lapse of information was that there was no knowledge of ATR within SAS. However, ATR was described in manuals by the aircraft manufacturer which every operator is obliged to know. Even though the system was developed for use in procedures not applied by SAS, a sufficiently careful study of the manuals should have led to SAS noting the system and training its pilots in its function."

                      Full Wiki on the accident is at:



                      I guess this bolsters my confidence that the MAX issues can be resolved since obviously the MD-81 and its off-spring survived quite successfully after this accident (although admittedly there were no casualties in this one which is amazing in and of itself).

                      Chris
                      One thing it has in common is that the incident occurred at very low altitude where there is not very much time and pilots cannot be expected to always think and act reliably. You could argue that, regardless of the specifics of the MD-81, the initial goal in a compressor stall is to reduce the EPR, and CRM dictates that while one pilot is concentrating on flying, the other is working the engine problems (as Sullenberger and Skiles did). Therefore the PNF should be closely monitoring the engine instruments, so if the N1 comes back up despite the thrust reduction (due to the unknown ATR system) or the EPR is not reducing as expected, the throttles need to be brought back further to avoid destruction. More training on engine recovery procedures might have prevented it, but I think that assumption is going to vary by the specific pilot's ability to maintain a clear head in a critical situation at such low altitude. Essentially, ATR was a stealth factor and you don't wan't stealth factors, but the goal of any compressor stall is to obtain a result in the engine instruments so the focus must be placed there and thrust must continue to be modified, for whatever reason, until the goals are achieved. Otherwise, you break the engines.

                      The main dissimilarity here is that the system WAS described in the FCOM. I really can't fathom why a person entrusted with a passenger airliner wouldn't study the FCOM and professionally familiarize themself with ALL the aircraft systems, but it seems there are a good number of pilots who just want to skip the homework and jump in and fly the damn thing with their almightly universal airmanship. IMHO, there is no excuse for a MD-81 pilot to not be aware of an MD-81 system behavior that is described in the FCOM, even if that pilot is never given training on it. IMHO, there is an inherent responsiblity for a pilot to take it upon themselves to study the manual as if they were monks and it were was the bible and know the aircraft they are commanding. IMHO this is not asking too much.

                      But in the case of the 737-MAX, the stealth factor wasn't to be found in the scriptures.

                      Comment


                      • i don't totally disagree with you evan, but you also have to keep in mind the "information overload" factor. in the last month or so, i heard some aviation "expert" rambling on about what if anything boeing did wrong. he agreed that boeing should've disclosed mcas more clearly and develop a training program for it. he also defended boeing by saying that while aircraft have become incredibly complex, there really is no need for pilots to be taught and expected to recall the function of every single system down to the bits and bytes. for example, does an airbus pilot really need to understand the details and decision process the flight computers go through in prohibiting a her/him from going ballistic? i doubt it. but the pilot does need to be told, "hey, no matter how hard you yank that sidestick back, you will never achieve more than x degrees of nose up attitude, and the FCC will decide what that degree will be given the then current situation."

                        the real question is, at what point does overload begin?

                        Comment


                        • Originally posted by TeeVee View Post
                          i don't totally disagree with you evan, but you also have to keep in mind the "information overload" factor. in the last month or so, i heard some aviation "expert" rambling on about what if anything boeing did wrong. he agreed that boeing should've disclosed mcas more clearly and develop a training program for it. he also defended boeing by saying that while aircraft have become incredibly complex, there really is no need for pilots to be taught and expected to recall the function of every single system down to the bits and bytes. for example, does an airbus pilot really need to understand the details and decision process the flight computers go through in prohibiting a her/him from going ballistic? i doubt it. but the pilot does need to be told, "hey, no matter how hard you yank that sidestick back, you will never achieve more than x degrees of nose up attitude, and the FCC will decide what that degree will be given the then current situation."

                          the real question is, at what point does overload begin?
                          I guess the answer to that question is: how much intellectual ability can we expect from pilots?

                          If I had it my way, becoming an airline pilot (and thus the protector of hundreds of live every day) would require a strenuous discipline both in traditional piloting knowledge and engineering knowledge. The reason for this lies in the new reality of the job. There is no longer a flight engineer. The decision to remove the flight engineer involved the assumption that the pilots could take over those responsibilies through the digital flight deck provisions. Those provisions are meaningless if the pilots do not also have the flight engineering knowledge that has been removed with the flight engineer.

                          Case in point: In the aforementioned MD-81 incident, I feel pretty certain that a dedicated and competent flight engineer would have been aware of the ATR issue and would not have blown those engines.

                          Where do you draw the line? In terms of systems and architecture, pilots should know everything that is contained in the FCOM (MCAS should have been contained in the FCOM). Therefore, the FCOM (and FCTM's) has to be written to include everything pilots must know for both normal and abnormal operations. Knowing the FCOM from cover to cover cannot be considered "too much information". Before being given a type-rating, pilots should be extensively tested on FCOM knowledge. In addition to checkrides, pilots should be periodically quizzed on systems as described in the FCOM and the ramifications they have in abnormal situations. Moreover, pilots should feel a moral responsibility to be constantly augmenting their training with a general study of the aircraft and abnormal ops and upset recovery piloting techniques. I can't say it enough, piloting should come with a dreadful sense of responsibility.

                          That said, with an apparent pilot shortage around the world, and with intellectually-driven people preferring other paths in life, this could prove to be a problem. But the solution lies in vetting pilots as best we can for intellectual ability and training them well beyond the minimal 'need to know' standard of the puppy-mills and third-world flight schools.

                          Comment


                          • Originally posted by Evan View Post
                            I guess the answer to that question is: how much intellectual ability can we expect from pilots?

                            If I had it my way, becoming an airline pilot (and thus the protector of hundreds of live every day) would require a strenuous discipline both in traditional piloting knowledge and engineering knowledge. The reason for this lies in the new reality of the job. There is no longer a flight engineer. The decision to remove the flight engineer involved the assumption that the pilots could take over those responsibilies through the digital flight deck provisions. Those provisions are meaningless if the pilots do not also have the flight engineering knowledge that has been removed with the flight engineer.

                            Case in point: In the aforementioned MD-81 incident, I feel pretty certain that a dedicated and competent flight engineer would have been aware of the ATR issue and would not have blown those engines.

                            Where do you draw the line? In terms of systems and architecture, pilots should know everything that is contained in the FCOM (MCAS should have been contained in the FCOM). Therefore, the FCOM (and FCTM's) has to be written to include everything pilots must know for both normal and abnormal operations. Knowing the FCOM from cover to cover cannot be considered "too much information". Before being given a type-rating, pilots should be extensively tested on FCOM knowledge. In addition to checkrides, pilots should be periodically quizzed on systems as described in the FCOM and the ramifications they have in abnormal situations. Moreover, pilots should feel a moral responsibility to be constantly augmenting their training with a general study of the aircraft and abnormal ops and upset recovery piloting techniques. I can't say it enough, piloting should come with a dreadful sense of responsibility.

                            That said, with an apparent pilot shortage around the world, and with intellectually-driven people preferring other paths in life, this could prove to be a problem. But the solution lies in vetting pilots as best we can for intellectual ability and training them well beyond the minimal 'need to know' standard of the puppy-mills and third-world flight schools.

                            Spoken like the professional that you are right?

                            Comment


                            • Originally posted by BoeingBobby View Post
                              Spoken like the professional that you are right?
                              Spoken like a person who puts his life in the hands of professionals. Feel free to add your own wisdom.

                              Comment


                              • Originally posted by Evan View Post
                                Spoken like a person who puts his life in the hands of professionals. Feel free to add your own wisdom.
                                I will have to discuss it with LH, I'll get back to you.

                                Comment

                                Working...
                                X