Boeing - Design Issues...

Discussion in 'Rules and Regulations / Flight Safety / Better Pil' started by TXFlyGuy, Apr 11, 2019.

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  1. Oct 8, 2019 #261

    BJC

    BJC

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    I have no problem with an industrialized country requiring that their defense budget be spent on domestically produced products. I do object to alliance member nations not contributing an equal percentage of their GDP to the alliance at the expense of US tax payers.

    My point is that the set of circumstances that have led to the current Boeing situation is much more complex than is being discussed on HBA.

    Running a business is much like designing a homebuilt airplane (or a type certificated one). It involves a series of interacting compromises, any one of which is subject to second guessing and criticism from participants and bystanders alike, many of whom are ready to say “I told you so ...” when something goes wrong.


    BJC
     
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  2. Oct 8, 2019 #262

    Speedboat100

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    I have notissed the hard way by making flying models that if anything can go wrong it certainly will go.

    Somewhere on the line the understanding of the aeroplane operating by 2 pilots was lost. This is very common in a business making that the real goal can be lost on the way.
     
  3. Oct 8, 2019 #263

    trimtab

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    There still seem to be people that think it is OK to design a mass transit aircraft that can be placed into an unrecoverable configuration by a automatic system controlling a primary flight control through the failure of a single unreliable sensor.

    That in itself is truly an astounding judgement.

    It also seems that many would blame average people (pilots) before they would blame such a judgement that was made to save time and money to get a product kicked over the wall with fingers crossed.

    The difference with the MCAS situation is that it would most likely deploy in one of the most critical phases of flight. The trim jack screw binding probability in the past was really not a factor for the takeoff portion of the flight to the degree that the MCAS exposed it to. And not disclosing the new input to the average people (pilots) was a deliberate act of negligence.

    All Boeing had to do to help prevent average people (pilots) from crashing their defective planes was allow an MCAS only disconnect, train the pilots for this mythical recovery maneuver that failed TWO consecutive reviews by test and evaluation research pilots to realize they had ridiculous expectations of human factors.

    All Boeing did was click the heels together of their ruby slippers three times and hand out bonuses to C-level execs. Their job was done.

    So- train average people to make up for an easily design-averted accident and expect some Gaussian distribution of successes and failures, or fix the defect and probably never see the problem in the first place.

    Aircraft for public transportation should not be needlessly designed to require exceptional skills to recover from failures in automation during relatively normal flight maneuvers. I class the recovery from a low altitude dive that requires an even more extreme dive at the ground to recover from due to primary flight control immobilization to be something falling into the realm of "exceptional maneuver" that has a substantial probability for problems. That isn't 20/20 hindsight. I think a majority of engineers and pilots would make the same conclusion as soon as it was presented.
     
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  4. Oct 8, 2019 #264

    BJC

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    Since you quoted no one, and that statement followed my post, you may be including me as one of those people. If you are, you are mistaken.


    BJC
     
  5. Oct 8, 2019 #265

    BJC

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    How much were their bonuses, and what, exactly, were they for?


    BJC
     
  6. Oct 8, 2019 #266

    davidb

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    There’s no one that thinks that is Ok. There are however plenty of people who believe the issue is as you have portrayed it.

    The “single failure” has to go through three phases of inappropriate pilot actions before it is unrecoverable. In my world, The crews involved were not average and did not do the things average pilots do.
     
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  7. Oct 8, 2019 #267

    trimtab

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    Nope. I was referring to the Gladwell piece. The half life of Gladwell pieces gets shorter with each overwrought effort.

    As for a flight crew needing to go " ...through three phases of inappropriate actions before it is unrecoverable", the solution to prevent the crew from having to "go through" anything was nearly certainly in the grasp of Boeing through the implementation of a) an MCAS disconnect, b) using more than one sensor to determine conflicts, c) actively training pilots to meet the requirement for more skill to avert disaster that the MCAS system presented. They felt that the design choices would mean endangering the promises the B-school boys made.

    It is far from certain or "firmly in the grasp" of a pilot population with human factors involved and a range of abilities to avert eventual disaster by training them to address the potentially fatal design defect. They chose the economic expedience. But even that choice isn't necessarily the issue. Many (if not most) socially acceptable engineering choices demand economic parameters. The difference here is that the company made the economically expedient choice apparently without considering the consequences of the fundamental engineering case at all.

    There is no way certification for a new GA aircraft could proceed if, through a combination of factors (including "three inappropriate actions"), a flight control system could become fixed in a position with a near certain fatal outcome in an episodic or repeatable manner, particularly through the failure of a single sensor with no ability to determine the health of said sensor. The certification requirements for transport category aircraft are more stringent.
     
  8. Oct 8, 2019 #268

    davidb

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    Trimtab, following your logic, no current airliner could pass certification. Engine failure? Is it ok or not to require certain pilot actions in order to safely recover an aircraft with engine failure?

    The scenario these crews faced, while a bit unusual, is arguably easier to handle than an engine failure. They get a pass on raising the flaps. Even though they should have left them at the takeoff setting, probably half the average pilots in my world would have raised them. That brings them into the second phase where MCAS does the trim thing. Nobody gets a pass here. It is just too intuitive. You simply keep it in trim and if it repeatedly tries to move, you turn it off. This really puts into question their training program and leads one to wonder what will happen when they are faced with any number of malfunctions.

    I suspect it is uncommon at these carriers to do much if any hand flying other than the bare minimum. That is unacceptable in any version of the 737 including the Max. It is a hands on airplane. Many malfunctions require hand flying as the autopilot is by design not available. Had they typically hand flown departures through to enroute climb as do all carriers I’m familiar with, the trim anomaly would likely been handled appropriately.

    That the second crew repeatedly tried to engage the autopilot given their indications is ironclad proof they were not qualified to be in the cockpit of a 737...in anyone’s world. Again, I’m not blaming the crew but I do blame whoever is or should be responsible for training and crew certification.

    Edit add: Again, I don’t give Boeing a pass for poor design implementation. They most certainly did unacceptable things with the system. I just want to point out that the aircraft itself is not the whole story behind these tragedies.
     
    Last edited: Oct 8, 2019
  9. Oct 18, 2019 #269

    trimtab

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    "...following your logic, no current airliner could pass certification. Engine failure? Is it ok or not to require certain pilot actions in order to safely recover an aircraft with engine failure?"

    The scenarios are entirely different. Are there automated systems that are dependent on a single error-prone sensor for output, where failure to take action will mean certain death for 340+ humans, when simple changes to that system avoid the entire problem?

    I'm interested. Those kinds of problems, deliberately incorporated into the design of the aircraft, would prevent certification. The Boeing example is more similar to the Ford Pinto fuel tank baffle debacle or the resistance to seat belts by the industry than what Boeing would like the public (and regulators) to believe.
     
  10. Oct 18, 2019 #270

    plncraze

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    The text messages from the former Boeing pilot are interesting. He seems very disturbed about the airplane's behavior in the simulator. This pilot now is a first officer with Southwest.
     
  11. Oct 18, 2019 #271

    Vigilant1

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    There are probably hundreds of such systems. It isn't unreasonable to expect that the crew perform in a competent manner. We can discuss what the definition of "competent" should be, but your definition amounts to "walk away safe," and it is unreasonable.

    Example: What if the cabin pressure sensor is faulty and results in a cabin pressure that is too low? By your standard, since the crew must actually do something and failure to do something could result in the loss of all on board-- it is unreasonably unsafe.

    Yaw dampers, electric trim, fuel system management, landing gear position, door interlock warnings, primary flight controls on the most sophisticated airplanes--failure of a single sensor results in a condition where the crew must recognize an anomalous situation and respond properly. The issue is: Has the system been designed so that an anomalous situation can be readily detected and the appropriate action can be taken by a properly trained crew?
     
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  12. Oct 19, 2019 #272

    Doggzilla

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    Enough of the crew blaming.

    As has been stated repeatedly, the jack on the trim tab would jam and move only one direction, further nose down. This made all procedures in the POH completely useless.

    Boeing knew this, as it was in the POH prior to 1982.

    According to Boeing’s own test pilots, the only way to fix the problem was to pull back with both pilots simultaneously and go into a nose up ballistic trajectory...then drop the controls
    to go zero G in order to relax pressure enough to get the stuck jack to move freely.

    That is not the same as a pilot having to flip a switch or some other basic responsibility.

    It was an extremely dangerous design with a difficult response, and no pilots after 1982 were taught proper responses.

    This is 100% fault of Boeing for knowingly hiding the issue and removing proper training from the manuals.
     
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  13. Oct 19, 2019 #273

    Doggzilla

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  14. Oct 19, 2019 #274

    plncraze

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    So this was the screwjack issue listed in the Lion Air crash? If I remember correctly the "hard over" issue was also hard for Boeing to admit even after two crashes. According to the "Flight 427" book the actuator was supposed to be impossible to lock up and under very cold conditions it would lock.
     
  15. Oct 19, 2019 #275

    Doggzilla

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    Yes the jackscrew was found jammed down in both aircraft.
     
  16. Oct 19, 2019 #276

    Vigilant1

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    We've been through this many times already. If the crew doesn't perform appropriate and very intuitive procedures (i.e. keep the airplane in trim), then pressures on the jackscrew can eventually become too great to be overcome with the electric trim or the manual trim wheels.

    Similar to:
    1 ) If you get an engine fire and don't take appropriate action in a timely manner (turn off the fuel, pull the fire handle), the fire can eventually burn through the nacelle and compromise the main spar. That's not a design flaw.

    2) If you have an engine failure and don't immediately apply appropriate controls, result may be a situation in which return to level flight is not possible, or cannot be accomplished without very great loss of altitude. That's not a design flaw.

    I am >not< saying that MCAS cannot be improved, or that all is fine. And, as I've stated before, I have great sympathy for the crews involved in what must have been a terrifying situation.
     
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  17. Oct 19, 2019 #277

    Wanttaja

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    Actually, Instant Messages, not emails.

    The only reason I point this out was that Boeing instructed its employees to NOT save emails. We were supposed to read and delete. I always assumed that this was in order to prevent leaving a liability trail.

    Don't know if IMs were subject to the same policy. Suspect so....

    Ron Wanttaja
     
  18. Oct 19, 2019 #278

    davidb

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    I’m not blaming the crews. I’m blaming crew training as well as Boeing. The jack screw loading issue will not go away as part of any retrofit to any model of the 737. You described the jack screw unloading procedure somewhat accurately but one doesn’t get to that point if one is adhering to the POH. It’s an extreme situation that is only reached if you don’t do the memory item response to runaway trim or if you don’t do the normal pilot thing of keeping it trimmed.

    The crews were certainly faced with a confusing mix of indications that would challenge the best pilots but the final outcome should not have occurred regardless of Boeing’s poor design oversight.

    I think some critics who aren’t pilots are missing some basic points in the discussion.
     
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  19. Oct 19, 2019 #279

    Doggzilla

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    There is no reasonable action the pilots could have taken. The entire issue is being vastly understated.

    Consider the entire picture of everything that was going on and not just the trim wheel.

    This was not just a slow tug on the controls, it was occurring while the pilots were also being screamed at by a near total instrument failure. The pilots were being told everything BUT what was actually occurring.

    The MCAS has no warning that it has failed and the other instruments were giving false alarms. The multiple false alarms screaming at the pilots would have naturally drawn their attention to the instrument failures and away from the trim system that is not indicating a failure.

    >>>>>>>The one flight that was saved a few days earlier was because a pilot riding jumpseat had noticed the trim wheel moving while both on duty pilots were paying attention to the rest of the cockpit instruments going crazy with false alarms.<<<<<<

    It was a complete fluke that the third flight was even saved. There is absolutely no way any pilot would have understood what was going on, since all of the information and alarms were showing wrong data, and the pilots were not even aware the trim system could even do that in the first place.
     
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  20. Oct 19, 2019 #280

    Vigilant1

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    Just wrong in too many ways to address.
     
    Last edited: Oct 19, 2019

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