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Thread: Lion Air Flight 610 Crash

  1. #151
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    Once again, as I understand it, the center of gravity not an issue here. My retired pilot friend explained that when the loading of cargo and fuel was completed, he was notified of the weight distribution and he set the trim accordingly just before takeoff in accordance with a table in the flight manual. Of course they did the best they could to locate the c/g so it could be trimmed with the least amount of drag. He said that the distribution of passengers in a large airliner was not a problem.

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    Quote Originally Posted by Hornblower View Post
    My educated guess is that changing it to a tri-jet would have made it a different enough airplane that the need for new type certification for the crew would have been ruled out.
    A tri-jet derivative of a 737 would be a new aircraft; it would need its own type certificate. If I remember my terms correctly, pilots get endorsements for different aircraft; aircraft get type certificates. The various 737 models have amended versions on the same type certificate. A new endorsement may be needed for anything that changes a pilot’s interaction with the aircraft, even something with no aerodynamic impact, such as a different avionics suite.
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  3. #153
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    The type certification is a strict system. A nearby reviver of antique aircraft bemoans that the cork based carb. floats of his Tiger Moth cannot be changed for a better modern material. So avoiding a type change must have been a big factor in the Boeing decision.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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    Quote Originally Posted by profloater View Post
    cork based carb. floats of his Tiger Moth
    Just an innocent question, but what in the world is a carb. float? It sounds like a newfangled kind of ice cream soda made out of graphite...
    As above, so below

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    Quote Originally Posted by Jens View Post
    Just an innocent question, but what in the world is a carb. float? It sounds like a newfangled kind of ice cream soda made out of graphite...
    Ha, I like that, a black cream soda float would be interesting to try, I mean a carburettor float and those old biplanes, which still fly around, have one made of varnished cork, a rather specialised design, and not without problems. But it's part of the approved and proscribed type.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  6. #156
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    Check out this site:
    https://www.theverge.com/2019/5/2/18...error-mcas-faa
    If their accounts are accurate, it appears that in each case use of the stab trim switches on the yoke was overriding MCAS and correcting the trim. It would appear that the pilots could have recovered by using the switches and then immediately pulling the cutout switches, before MCAS could kick in again. Apparently the crew on the previous flight in the Lion Air plane had successfully done just that, and that confusion precluded similar action with the flights that went down.

  7. #157
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    Quote Originally Posted by profloater View Post
    Ha, I like that, a black cream soda float would be interesting to try, I mean a carburettor float and those old biplanes, which still fly around, have one made of varnished cork, a rather specialised design, and not without problems. But it's part of the approved and proscribed type.
    My educated guess is that this is a tiny niche market, and that the part manufacturer considers it not worth the expense of getting an airworthiness certificate for a float made of modern material.

  8. #158
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    Quote Originally Posted by Hornblower View Post
    It would appear that the pilots could have recovered by using the switches and then immediately pulling the cutout switches, before MCAS could kick in again. Apparently the crew on the previous flight in the Lion Air plane had successfully done just that, and that confusion precluded similar action with the flights that went down.
    Perhaps they could have mentioned it as they passed off the plane! But just imagine this intricate dance of back-and-forth between the yoke and the cut-out switches, just to fly a plane that is supposed to be designed to fly. Should this really be viewed as such a routine part of flying an airplane that one crew wouldn't even mention it to the next? The killing problem seems to be that by the time the doomed crew knew they were dealing with a faulty AoA sensor and a malicious MCAS as a result, they could no longer use the stab trim switches on the yoke, because those are purely manual. and the airspeed had gotten too high. I still can't get over pilots feeling like their own safety provisions are trying to kill them, and quite successfully at that.

  9. #159
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    I'm hearing a lot about the flight crew retracting the flaps with a stick shaker which is against the published procedures. But the thing is, the stick shaker was false so that decision should not have doomed the flight. The aircraft was heading to an overspeed, which is why they retracted the flaps, so they had plenty of energy to fly clean. Also, only one stick shaker was going off so that probably made them judge that the stick shaker was false, not the overspeed, which was consistent between the two sides.

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    Here are two links from earlier in the thread, pasted here for convenience.

    https://www.youtube.com/watch?v=zGM0...youtu.be&t=149
    https://www.youtube.com/watch?v=9jNbayma9dM&app=desktop

    Mr. Brown's opinion is that the Max in not inherently unstable, contrary to impressions created by possibly ill-informed news media people, and that pilots in simulators barely felt the difference with and without MCAS in high AoA situations. Perhaps FAA was overzealous in requiring it for a common type rating, but erring on the side of caution is fine if the measures are executed properly.

    It appears to me that fixing the software faults in the Max is going to be the relatively easy part. Reversing the evolution of institutional bad habits at Boeing and FAA will be harder, as will restoring public confidence in them, and the way some of Boeing's top people have talked to date seems to be making it worse. Their attorneys must be cringing, unless they are part of the problem and are giving poor legal advice, a possibility about which we can only speculate at this point.

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    Quote Originally Posted by profloater View Post
    The type certification is a strict system. A nearby reviver of antique aircraft bemoans that the cork based carb. floats of his Tiger Moth cannot be changed for a better modern material. So avoiding a type change must have been a big factor in the Boeing decision.
    Is anyone trying to get a STC for an alternative carburetor float?

    The 737Max is probably still on the same type certificate as earlier 737s; they wanted to avoid pilot having to be endorsed tor a 737Max vs a 737NG. They almost certainly need a different type endorsement than for the original 737.
    Last edited by swampyankee; 2019-May-10 at 08:42 PM.
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  12. #162
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    Quote Originally Posted by swampyankee View Post
    Is anyone trying to get a STC for an alternative carburetor float?

    The 737Max is probably still on the same type certificate as earlier 737s; they wanted to avoid pilot having to be endorsed tor a 737Max vs a 737NG. They almost certainly need a different type endorsement than for the original 737.
    My bold. That is the "difference training" my pilot friend had when he switched from the original model 200 to the NG series. I don't remember how long he said it took, but it was far short of the expensive classroom and simulator time needed for switching to the MD-88 when he went to another airline.

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    Quote Originally Posted by Hornblower View Post
    Mr. Brown's opinion is that the Max in not inherently unstable, contrary to impressions created by possibly ill-informed news media people, and that pilots in simulators barely felt the difference with and without MCAS in high AoA situations.
    I don't think the problem is so much the inherent instability of the plane, it was overlooking two basic principles that seem to me by basic common sense should always be in place any time a system is designed to take control of the plane away from the pilots for their own good:
    1) the system should utilize at least as much information about what is happening to the airplane as what the pilots are using, and
    2) if the system is broken in some obvious way (like it is trying to fly the plane into the ground), it should be simple for the pilots to turn it off without losing some essential function for flying the plane themselves.

    MCAS was built to violate both those principles. It took all its input from a single AoA sensor (it didn't even take into account that the airspeed was redlining-- is that really a stall risk situation?), and turning it off requires replacing hydraulic control of the stabilizers with manual control. Both of these violations are particularly dangerous during liftoff, when high thrust is advisable and a low AoA is especially fatal. If pilots in the simulators hardly noticed the MCAS, that may be because it wasn't malfunctioning during takeoff, in a situation where they did not know which system was failing until they couldn't fly the plane without hydraulic assistance.

    You can kind of imagine the conversation: "Oh yeah, these planes add an MCAS system which you won't hardly feel, it just makes it harder to stall the aircraft. Er, did I forget to mention it will fly the plane right into the ground if the AoA sensor breaks on takeoff?"
    Last edited by Ken G; 2019-May-11 at 11:57 PM.

  14. #164
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    Lion Air Flight 610 Crash

    Quote Originally Posted by Ken G View Post
    I don't think the problem is so much the inherent instability of the plane, it was overlooking two basic principles that seem to me by basic common sense should always be in place any time a system is designed to take control of the plane away from the pilots for their own good:
    1) the system should utilize at least as much information about what is happening to the airplane as what the pilots are using, and
    2) if the system is broken in some obvious way (like it is trying to fly the plane into the ground), it should be simple for the pilots to turn it off without losing some essential function for flying the plane themselves.

    MCAS was built to violate both those principles. It took all its input from a single AoA sensor (it didn't even take into account that the airspeed was redlining-- is that really a stall risk situation?), and turning it off requires replacing hydraulic control of the stabilizers with manual control. Both of these violations are particularly dangerous during liftoff, when high thrust is advisable and a low AoA is especially fatal. If pilots in the simulators hardly noticed the MCAS, that may be because it wasn't malfunctioning during takeoff, in a situation where they did not know which system was failing until they couldn't fly the plane without hydraulic assistance.
    Picking a nit but the stabilizer trim system electrically moves a jack screw and the manual trim wheels do so with cables. Not hydraulic.

    That said your use case is on point.

    To me there are three glaring issues in this mess;

    1. Single sensor dependency
    2. Inadequate training and notification
    3. Inability to disable MCAS

    It also sounds like the 737 flying cohort could use refresher training on manual trim systems and procedures.
    Last edited by schlaugh; 2019-May-12 at 02:47 AM.

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    Quote Originally Posted by schlaugh View Post
    Picking a nit but the stabilizer trim system [i]electrically [/]moves a jack screw and the manual trim wheels do so with cables. Not hydraulic.
    Point taken.

    To me there are three glaring issues in this mess;

    1. Single sensor dependency
    2. Inadequate training and notification
    3. Inability to disable MCAS

    It also sounds like the 737 flying cohort could use refresher training on manual trim systems and procedures.
    I agree, those three things shouldn't be too hard to fix but there would appear to be a deeper problem as to why they were allowed through the door in the first place.

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    Quote Originally Posted by schlaugh View Post
    Picking a nit but the stabilizer trim system electrically moves a jack screw and the manual trim wheels do so with cables. Not hydraulic.

    That said your use case is on point.

    To me there are three glaring issues in this mess;

    1. Single sensor dependency
    2. Inadequate training and notification
    3. Inability to disable MCAS

    It also sounds like the 737 flying cohort could use refresher training on manual trim systems and procedures.
    Is it known (well, publicly) yet why the MAX was certified, given that MCAS relied on one sensor only?

    Not to put too fine a point on this, but to me that’s close to criminal negligence.

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    My interpretation is that the single sensor design was a case of force fitting the argument to meet the desired conclusion.

    If the MCAS was designated safety critical, it would have required more pilot awareness, which may have required training. Since the goal was no training, MCAS had to be designated not safety critical.

    If it is now not safety critical, it doesn't need two sensors.

    And if they did put in two sensors, that would only have given it the opportunity to identify an input fault and cut out. If MCAS cuts out, the handling characteristics are no longer NG-like and so pilots need to be trained for that. So not giving the MCAS the opportunity to identify it is wrong, means it will not cut out.

    Disclaimer: I have not worked on this plane so the above is not based on expert knowledge but based on what I have read around and we all know how trustworthy the Internet is.

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    I think Glom got it: MCAS was added so the aircraft handling matched that of the 737NG, not to deal with nasty stall-spin characteristics, as would be the case with stick pusher or a stick shaker. The articles I’ve seen say that MCAS was added so the 737Max had the same stick force vs AoA as the 737NG, not that the Max became unstable. In general, swept wing aircraft have to be carefully designed, as the tips of swept wings tend to stall first, meaning the part of the wing is ahead of the C/G, and the amount of stick force required to further increase AoA decreases, sometimes becoming negative, leading to uncontrollable pitch-up.
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    But what I don't get is, at what point does pointing the plane down every few minutes get interpreted as a different "feel" for flying the plane? Isn't feel something that happens in the moment, not every nine minutes?

    I get that airlines need to make profits to stay in business, and the shareholders always want more, but obviously poor safety decisions always end up costing more (in money, not just lives) than they save. An airline should know that better than anyone, for crying out loud. So if it's true that the whole MCAS fiasco was either a complete breakdown in communication or worse, a purposeful effort to deceive, then it's pretty clear that the existing lines of communication between the airline, the pilots, and the FAA need serious overhaul-- in the best interests of not only the passengers, but also the shareholders. Not to mention the fact that shareholders fly in planes too, probably more than most. The job of the FAA is to save airlines from their own short-sighted decisions, not to be complicit partners in short-sighted decisions.

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    CNN Business goes over the gantlet that the Boeing 737 Max must roll through before it flies again. Also, the FAA's gantlet.

    https://www.cnn.com/2019/05/13/busin...val/index.html
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

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    Quote Originally Posted by Roger E. Moore View Post
    CNN Business goes over the gantlet that the Boeing 737 Max must roll through before it flies again. Also, the FAA's gantlet.

    https://www.cnn.com/2019/05/13/busin...val/index.html
    thanks for introducing "gantlet" to the lexicon of punishment that Boeing and the FAA now face. That report says that since the crashes Boeing has spent a billion dollars on software changes, can that be right? And how can a warning system be "accidentally" turned into an option? This gets more curious and my guess is that more internal conflict between engineers and higher management may start to emerge.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Thanks Glom and swampyankee (caveat/disclaimer acknowledged).

    Yeah "criminal" requires a fine appreciation of the relevant laws; perhaps "gross negligence"? On the part of the FAA as well as Boeing.

    Is there no one - in Boeing or the FAA - whose real job it is to relentlessly look for critical safety issues (such as MCAS relying on just one sensor, and no account taken - in MCAS - of the possibility of a faulty sensor), irrespective of the (profit driven) design approach?

    I may be mis-remembering, but didn't Toyota (or some other Japanese car maker?) have a "anyone can stop the line" rule (a rule which was actually implemented)? Sure, the failure here isn't, strictly speaking, part of "the line", but it's easy to generalize to allowing a "critical safety software review team" to call for a halt.

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    Quote Originally Posted by Jean Tate View Post
    I may be mis-remembering, but didn't Toyota (or some other Japanese car maker?) have a "anyone can stop the line" rule (a rule which was actually implemented)? Sure, the failure here isn't, strictly speaking, part of "the line", but it's easy to generalize to allowing a "critical safety software review team" to call for a halt.
    "Stop the Line" manufacturing is explained below at the link. It was a Toyota principle.

    https://leanbuilds.wordpress.com/tag/stop-the-line/
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

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    the Toyota method was adopted as a quality raising strategy. Other companies have followed although it is a brave starting point. The reason the stop has to be drastic is that while some errors require minor change, some require rethinking the whole process or the whole design. It does work and is relevant mainly where production is unchanging. Change is the issue that requires even more drastic thinking because reliability cannot be theoretically assessed. It is experiential. That is why simulators are so important in aircraft design, An approach where a change is deemed necessary but retraining is deemed undesirable is a priori a bad idea for an aircraft although the commercial reasons are clear enough. So it is right that the FAA are getting criticism because someone should have done the due diligence on the changes required for the new version. I see no special difficulty in simulating the new "stick feel" hardware/software and loss of a sensor would be standard protocol in the simulator. Will we hear about that?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    This NYT article, from yesterday, is consistent with what Glom wrote, in an earlier post. Before Ethiopian Crash, Boeing Resisted Pilots’ Calls for Aggressive Steps on 737 Max

    This is particularly shocking, IMHO, in light of what subsequently happened (the Boeing-pilots meeting happened after the Lion crash but before the Ethiopian one): "He [Mike Sinnett, a Boeing vice president] added that he felt confident that pilots had adequate training to deal with a problem, especially now that pilots — who were not initially informed about the new system — were aware of it." (yes, we have only the NYT's account, so salt grains are appropriate). The arrogance! The insouciance! It now seems that even Boeing itself did not know what bad "problems" could arise, caused by MCAS+faulty sensor, so there's no way they could have had any certainty that "pilots had adequate training to deal with" bad MCAS problems!

    I'm wondering what impact this will have on FAA certifications. I do not know how rigorously the equivalents in other countries do independent investigations before they certify a plane (e.g. to what extent do they "take the FAA at its word"), but there surely must be a lot of pressure - in Europe say - for a much more independent and rigorous process.

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    Yes, I think the main thing that has happened here, going forward, is that words by Boeing like "pilots have adequate training to deal with a problem," and by the FAA like "Safety is FAA's top priority," have come into serious doubt. Not just doubt that the words are correct, even doubt that the person saying them has any basis for them other than the desire that they be true. Words like that used to mean something, and a lot of how that whole process functions relies on those words being able to be taken at face value. Once there is a suspicion of insincerity, the relationship of the FAA and Boeing to the common airline traveler is seriously undermined and hard to recover in the near term. It certainly appears that 346 people died as a result of wishful thinking and an "if you say it enough times it may as well be true, even if it isn't" attitude. As everyday people we know it is rather easy to pull the wool over the eyes of those you want to convince, but as science students we also know there is nothing more futile in the long run than trying to pull the wool over the eyes of nature. This certainly seems to be a growing theme in modern times.
    Last edited by Ken G; 2019-May-15 at 02:07 PM.

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    the lesson after the crashes, it seems to me, not yet learned is that these days it will all come out in the court of public opinion (as well as in law courts) and the tardiness in admitting and eating the humble pie and getting ready to spend the necessary, the drawn out denials will do extra damage which might last for years. This is not a blip on the figures. No one can believe the second crash is just bad luck after the similarities with the first came out, and then the anger of the grounded airlines, then the stories about internal memos, the drawn out technical reports that will be too late and will add fuel to the flames. Not answered yet is whether the type continuity will be allowed in the long run, while market wise a new name for the plane is going to be essential, surely? They should accept the seemingly obvious, who wants to fly in a max 8 now?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Tense argument revealed between American Airlines pilots and Boeing rep in recording from Nov 2018. Pilots were not aware of MCAS system aboard plane, 1st crash had already happened.

    https://www.cnn.com/2019/05/15/us/bo...ots/index.html

    NYT version: https://www.nytimes.com/2019/05/14/b...ane-crash.html
    Last edited by Roger E. Moore; 2019-May-15 at 06:44 PM.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

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    Quote Originally Posted by Roger E. Moore View Post
    Tense argument revealed between American Airlines pilots and Boeing rep in recording from Nov 2018. Pilots were not aware of MCAS system aboard plane, 1st crash had already happened.

    https://www.cnn.com/2019/05/15/us/bo...ots/index.html

    NYT version: https://www.nytimes.com/2019/05/14/b...ane-crash.html
    Is there any difference in the two versions?

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    Quote Originally Posted by bknight View Post
    Is there any difference in the two versions?
    CNN version is a bit longer.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

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