Boeing - Design Issues...

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

Help Support HomeBuiltAirplanes Forum by donating:

  1. Oct 4, 2019 #241

    jedi

    jedi

    jedi

    Well-Known Member

    Joined:
    Aug 8, 2009
    Messages:
    1,780
    Likes Received:
    402
    Location:
    Sahuarita Arizona, Renton Washington, USA
    Come on out to Bergseth Field in Enumclaw on a nice summer weekend and take a demo flight with PSSA (Puget Sound Soaring Association). I would love to fly with you and enjoy all of your posts.

    Enumclaw (/ˈiːnəmklɔː/ ( listen) EE-nəm-klaw) is a city in King County, Washington, United States. ... The City of Enumclaw says the name means "thundering noise".
     
  2. Oct 4, 2019 #242

    jedi

    jedi

    jedi

    Well-Known Member

    Joined:
    Aug 8, 2009
    Messages:
    1,780
    Likes Received:
    402
    Location:
    Sahuarita Arizona, Renton Washington, USA
    A large part of the problem was that the pilots were not told that there was a "computerized flight control system" that could take over control of the trim system. The procedure that Boeing expected the pilots to use was titled "Runaway Trim". They did not have a runaway trim. They had an uncomanded trim that repeated itself via an automated system that was unknown to exist by the flight crew.

    I believe it was mentioned here that if they had turned on the automatic flight control system, AKA auto pilot, it would have overruled the faulty MCAS system they did not know existed.
     
    BBerson likes this.
  3. Oct 4, 2019 #243

    jedi

    jedi

    jedi

    Well-Known Member

    Joined:
    Aug 8, 2009
    Messages:
    1,780
    Likes Received:
    402
    Location:
    Sahuarita Arizona, Renton Washington, USA
    Boeing problems did not start in the 90's and the problems are not specific to Boeing. Boeing can be slow to admit to or recognize a problem when one exists. There are numerous examples but a good parallel example is the B-737 rudder hard over problem. PBS just replayed a documentary on that last evening on Modern Marvels or as it should have been titled, Modern Major Screwups; the Cal Tech Nuclear Reactor melt down, gigantic PA oil spill, and the loss of two B-737s killing all aboard.

    There were many other 737 incidents of rudder hard overs that did not result is loss of the plane and all passengers. My first knowledge was in 1972. The rudder problem was not taken seriously until about 1978 after the UAL and Northwest accidents . It took Boeing about 10 years to admit to the problem and propose a fix. Prior to that the problem was explained as something external to the aircraft or flight crew issues.

    Does anything sound familiar here?
     
  4. Oct 4, 2019 #244

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    9,548
    Likes Received:
    6,321
    Location:
    97FL, Florida, USA
    Pilot: “We have a problem.”
    Co-pilot: “What is it, captain?”
    Pilot: “The trim keeps trimming for nose down.”
    Co-pilot: “Trim system disabled. I’ll put it on the squawk list.”
    ....... later ....
    Pilot: “That was a difficult approach and landing.”
    Co-pilot: “Yes, but, as then say, ‘any landing that you can walk away from ...’”


    BJC
     
  5. Oct 5, 2019 #245

    Heavy Iron

    Heavy Iron

    Heavy Iron

    Member

    Joined:
    Aug 27, 2011
    Messages:
    7
    Likes Received:
    5
    Location:
    Dundalk, Ontario / Canada
    Uncommanded trim that is trying to hurt you is basically the definition of runaway trim. The runaway stabilizer procedure (which is a memory item, not something you are expected to look for in a checklist) has existed all 737 models since the 737-100 in 1967. The stab trim cutout switches have been in the same general area on the control pedestal since 1967.

    In both cases the AOA sensor failure caused erroneous MCAS activation but the electric stab trim was still fully functional and according to the FDR readouts did trim nose up when the pilots used it except for a short time when the stab trim cutout switches had been selected to cutout in the second accident.

    The autopilot on a 737NG or 737MAX cannot be engaged when there is an air data disagreement so it would not have been possible for them to use it. If an autopilot had been engaged before the AOA sensor failed, the autopilot would have immediately disengaged.

    I am not defending Boeing here, the MCAS system as designed had a lot of issues that should not have made it through a design review but the existing runaway stab procedure and the still operational electric trim and manual trim should have allowed a better outcome to those flights. There was a lot going on in the flight decks with the continuous stall warning/stick shaker, the airspeed and altimeter disagreement and the elevator feel shift module (activated by the stall warning) increasing the elevator column force required to pull the control wheels back.

    I agree fully with earlier posts by davidb, these accidents were crew training failures. The AOA sensor failure was the factor that started a chain of events that the crew was not prepared for and the MCAS design was a major contributor to the chain of events. I personally don't believe that including MCAS in the flight crew training presentation would have made any difference here. The training issue was of a more basic nature than one about details of MCAS.

    R.I.P. to the victims and my thoughts to their families and friends.

    Ron
     
    bmcj and PagoBay like this.
  6. Oct 5, 2019 #246

    PagoBay

    PagoBay

    PagoBay

    Active Member

    Joined:
    Nov 17, 2013
    Messages:
    41
    Likes Received:
    6
    Location:
    US Territory of Guam
    Have not been following this thread for a while, but surely the NY Times opinion piece by Wm. Langewiesche has come up.

    Here is a very detailed commentary explaining where the opinion piece failed to address the case in a factually correct manner. An excellent article and a must read for those who are attending to this controversy.

    14,000 Words Of "Blame The Pilots" That Whitewash Boeing Of 737 MAX Failure
    https://www.moonofalabama.org/2019/...that-whitewash-boeing-of-737-max-failure.html

    RMM - Guam
     
  7. Oct 6, 2019 #247

    trimtab

    trimtab

    trimtab

    Member

    Joined:
    Apr 30, 2014
    Messages:
    10
    Likes Received:
    6
    Location:
    rocky mountains, rocky, usa
    My CFI a few decades ago was a FO for USAir. He gave me a 737 POH from 1982. There is a procedure to recover from a runaway nose down trim condition where the aircraft is significantly out of trim (fast). The procedure is to push forward to dive the aircraft to unload the stab enough to move the trim wheel manually. In other words, the trim wheel is very difficult to potentially impossible to move when the servo is disabled and out of trim.

    My CFI confirmed this to me when I was 15, going so far as to say that "a lady would have great difficulty with trying to move the trim wheel if things really got out of whack". Apparently this was demonstrated in an actual flight test to him.

    Mr. Langewiesche clearly and directly mentions this issue in his article. It is nearly unnoticed in the popular press. It has been noticed, mentioned, and emphasized in other, more informed places.

    The only way out of the problem with a malfunctioning MCAS is to disable the servo. If the problem has progressed too far, disabling the servos may mean you die just as quickly as with the servos driving the plane into the ground. If you are going to die either way, it would seem to me to be logical to try something different....namely, turning on the servos since the pilots do not know that the MCAS was the issue. You know...to try something different instead of certain death.

    I have the POH mentioned in front of me.
     
  8. Oct 6, 2019 #248

    PagoBay

    PagoBay

    PagoBay

    Active Member

    Joined:
    Nov 17, 2013
    Messages:
    41
    Likes Received:
    6
    Location:
    US Territory of Guam
    @trimtab... I would very much like to hear your impressions after reading both the NYTimes piece and the response referenced in my post #246 above. Hard for me to sort out the key elements by which fault could be assigned. What is your view?
    AND... what exactly would restoring the servos accomplish? Please clarify.
    thanks
    RMM
     
  9. Oct 6, 2019 #249

    Voidhawk9

    Voidhawk9

    Voidhawk9

    Well-Known Member HBA Supporter

    Joined:
    Mar 26, 2012
    Messages:
    250
    Likes Received:
    138
    Location:
    Timaru, NZ
    Restoring electric pitch trim, obviously. Manual trim could not be used due to it being overwhelmed by aerodynamics forces, and the aircraft was way out of trim at this point.
     
  10. Oct 6, 2019 #250

    trimtab

    trimtab

    trimtab

    Member

    Joined:
    Apr 30, 2014
    Messages:
    10
    Likes Received:
    6
    Location:
    rocky mountains, rocky, usa
    The response to Mr. Langewiesche is spot on, of course. There is a fundamental defect that threatens lives in the 737 trim system when used with an MCAS system. The trim system is dangerous as well by itself, according to the POH maneuver (a maneuver that would be impossible or doubtful to execute in the takeoff phase), since the trim system can become hopelessly bound up when well out of trim. It needed the mysterious, undocumented MCAS system to create the problem in a critical flight phase, twice in a row.

    Airbus has a similar system to do what MCAS was meant to do on their A32x series. The difference is that the inhibit switch simply disconnects the system from the trim system or primary flight control system inputs. No harm, no foul. The Airbus system allows the servos (needs them, actually) to continue to operate with other inputs.

    The Boeing approach was to acknowledge that such a move would mean new pilot training or even threaten the grandfathered TC of the aircraft, so they did the dumb thing. There is no excuse outside of a B-school accounting class for the decision, and b-school judgments remain the primary drivers at Boeing and other technically complex product companies. If the faulty trim system was not made positively fatal by the new MCAS system, close to 346 people would probably still be alive, and the MAX program might still be flying.

    As for the comment about flipping on the servos again, perhaps it is better to imagine yourself less than a minute from impact, seeing the ground come up at you, the trim wheel frozen with the servos turned off. While you struggle to hold the elevator up, your FO is unable to budge the trim wheel. You realize that you and everyone else are about to be killed while you watch it happen, as if the horizontal stab were literally welded in place. There is nothing you can do. Since doing the same thing and hoping for a different result is a dumb idea, why not try something new and hope for a different result? Flip the servos on to see if you can clear the problem with the trim wheel? Nope. Now you are simply closer to certain, violent immolation. Turn it off. Ok? What else? maybe try again?

    I submit this is what happened to those people on board the planes- the pilots of the second flight repeatedly activated and deactivated the servos. Their fate was sealed from the start, their screams contained in their aluminum coffin mis-designed and sold and denied and covered up by Boeing. Their management (b-school boys, all) were repeatedly given promotions and bonuses to navigate out of the political flack in the early days of the crisis, and golden parachutes later when people had to be shown to be booted. Negligence is not something they teach in B-school, nor human safety engineering, nor much of anything really beyond accounting, finance, operations, "leadership" and recognizing a nice suit.

    Blame the pilots? Fine. Pilots are average people, by and large. Blaming the problem on pilots for a product that requires exceptional skills from exceptional people to avoid mass killing due to relatively known and plausible irreversible scenarios initiated automatically from stable flight conditions ---

    ---is a reasonable definition of a flagrant sociopathy.

    It is clear to me this problem would have killed more people if the consensus were that it was all pilot error. Looking at it from a Boeing fault point of view, it is likely that nobody would have died. That spells out where the changes should happen. For me, that spells out where the blame lies, as well.

    I've talked to a few 737 drivers about this in recent months, and some commented early on they would have been able to save everyone for sure if it had happened to them. They did not acknowledge the trim wheel binding issue. Perhaps, but I surmise from this that, if they had been in the same position as those unfortunate pilots, their own passengers and crew would be just as dead as the ones that did die.
     
    Last edited: Oct 6, 2019
    litespeed and Voidhawk9 like this.
  11. Oct 7, 2019 #251

    PagoBay

    PagoBay

    PagoBay

    Active Member

    Joined:
    Nov 17, 2013
    Messages:
    41
    Likes Received:
    6
    Location:
    US Territory of Guam
    @trimtab..
    Thanks for the thoughtful reply. Corporate culture / Profits First / Group Think / Human nature all combining for very unfortunate and, sadly, life consuming losses. Wish Mr. Langewiesche could be asked to respond to that blog point by point. That is a big problem in media today, on both sides of key issues, the big and loud voices get heard, while others with knowledge and detailed facts are off screen.

    Not to deflect from Boeing's Internal issues, but Socio-Cultural factors are always worth consideration by management including the cockpit. After Korean Air Flight 801 crashed on Guam in 1997, the airline hired a Canadian science writer, Malcolm Gladwell, to review the underlying internal factors that contributed to the crash. The result was a redo of corporate and specifically cockpit culture. See:
    https://www.theatlantic.com/nationa...-theory-everywhere-after-asiana-crash/313442/
    This theory was again brought up in the Asiana Airline 2013 crash in San Francisco. See:
    https://www.cnbc.com/id/100869966
    For a critique of Gladwell's "Ethnic Theory of Plane Crashes" See:
    https://www.businessinsider.com/blo...ladwell-ethnic-theory-of-plane-crashes-2013-7

    Really appreciate the expertise available on this forum. My first experience here some months back was not good at all. I was repeatedly bashed by forum stalwarts for speaking out about facts regarding a particular auto engine conversion company. I was even accused of being a shill and was sent a really vulgar animated cartoon reply by a "Well Known Member" telling me to GET OUT. A similar flaw in "Forum Culture" here where the old crew gets all aggressive with newcomers who have honest and fair views to present.

    I hope those guys will read this and do better in the future. That reply was deleted but I was left very cautious about posting here. So for me, as a fellow new member, your well considered thoughts and contribution here are doubly appreciated.
     
    jedi likes this.
  12. Oct 7, 2019 #252

    davidb

    davidb

    davidb

    Well-Known Member

    Joined:
    Jun 3, 2008
    Messages:
    1,663
    Likes Received:
    452
    Location:
    Vacaville, CA
    I don’t like the term “pilot error” but the pilots certainly didn’t do the correct things and in fact did some things I find counterintuitive as a 737 driver. I say they were situationally ignorant. That is not meant as a slam to those pilots but is a slam to the training they received.

    Boeing is guilty of allowing a design where a single failure, if handled incorrectly, can snowball into an unrecoverable situation. That should not have happened but it did. The aircraft system has been modified to prevent the same circumstances but...

    Situational ignorance (pilot error) is still lurking and waiting for the next thing engineers failed to account for. The pilots who are confident of being able to handle the situations these pilots faced are those who are somewhat if not intimately familiar with the stab trim system that started with the 707. Jack screw loading was a known, trained thing back in the 1950s. Everything the pilots of these tragedies needed to know was knowable since the 1950s.

    Boeing allegedly assumed pilots would know how to handle a trim malfunction. Most of us do. If we really want to fault Boeing for corporate greed, we can say they should not have sold aircraft to air carriers that have a substandard commitment to training.

    Few will acknowledge that the Max with the given MCAS and the given malfunctions was in fact controllable. Blame the manufacturer or blame the training? It’s not popular to accept that we had pilots ill trained to fly any version of the 737. Who’s responsible for the training? It’d be impractical to put the long term burden of training on the manufacturer.
     
    Vigilant1, PagoBay and BJC like this.
  13. Oct 7, 2019 #253

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,894
    Likes Received:
    397
    Location:
    Everywhere USA
    Remember, the trim tab becomes one directional above certain speeds. The jack jams.

    This was a known issue included in the POH until the early 1980s. For some reason Boeing removed the section about how to overcome it.

    It requires the pilots to pull up and then let go of the controls and basically coast ballistically to take pressure off the jack.

    So even if they had not cut power and had the trim motors, it was useless at those speeds.

    Also keep in mind the military tanker variant has a different system that has the same purpose but is safe to use. Boeing had a working system already and managed to screw it up on the Max.
     
    davidb likes this.
  14. Oct 7, 2019 #254

    davidb

    davidb

    davidb

    Well-Known Member

    Joined:
    Jun 3, 2008
    Messages:
    1,663
    Likes Received:
    452
    Location:
    Vacaville, CA
    Which tanker are you referring to and are you referring to an MCAS feature or the stab trim system? I know the stab trim system of the KC-135A is basically the same thing as all models of the 737 including the Max. Does the KC-135R model have some sort of MCAS that would have worked on the Max?
     
  15. Oct 7, 2019 #255

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,894
    Likes Received:
    397
    Location:
    Everywhere USA
    BBerson likes this.
  16. Oct 8, 2019 #256

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,894
    Likes Received:
    397
    Location:
    Everywhere USA
    Also, the MAX has a slightly different trim system. The two trim control switches are duplicates instead of pilot/autopilot separation switches like all older 737 variants have.

    So on older models the pilots can disable the automatic trim and keep their own. On the MAX this is not possible because both switches are exact duplicates (primary and backup) that control the entire system. This means the pilots have to turn off the entire trim motor system or nothing at all. No way to separate the pilots trim from autopilot trim.
     
  17. Oct 8, 2019 #257

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,894
    Likes Received:
    397
    Location:
    Everywhere USA
  18. Oct 8, 2019 #258

    davidb

    davidb

    davidb

    Well-Known Member

    Joined:
    Jun 3, 2008
    Messages:
    1,663
    Likes Received:
    452
    Location:
    Vacaville, CA
    Doggzilla, thanks for the clarification and source references. I have yet to read an article that doesn’t contain some misinformation and faulty analysis. We shouldn’t put too much faith in these articles. Even if we had a reporter in on the meetings between the engineers, test pilots and the FAA, I doubt the reporter could accurately present all the information.

    We have a reporter that notices the cutout switches are labeled different on the Max and assumes a functional option was taken away from the pilots. That’s false from a pilot’s perspective. Nothing changed operationally. The switches still do the same thing and the “old” thing he assumes was never an option.

    The KC-46 article has a point but is misleading. There’s no plug and play MCAS that could have been taken from it and installed on the Max. The author could have been clearer in that the concept of auto trimming stopping with opposing control column force should have been incorporated into the Max MCAS.
     
    BJC likes this.
  19. Oct 8, 2019 #259

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,894
    Likes Received:
    397
    Location:
    Everywhere USA
    If you read the article it actually has a former Boeing engineer confirm that the switches have been changed. The engineer confirmed this by checking the production change logs.

    I have personally talked to several former Boeing engineers who stated that the company made it nearly impossible to do their jobs properly, and that their complaints were ignored. And which resulted in them being threatened.

    Their standards have dropped so greatly in the last few years that the military ordered a halt in production due to the huge number of defects present in brand new aircraft.
     
    litespeed likes this.
  20. Oct 8, 2019 #260

    litespeed

    litespeed

    litespeed

    Well-Known Member

    Joined:
    May 21, 2008
    Messages:
    1,480
    Likes Received:
    293
    Location:
    Sydney
    I have absolutely no confidence in Boeing anymore nor the system of regulation in business and safety.

    A disaster designed and directed by the red right hand of greed.

    I note the problem airtankers are the ones Airbus should be supplying but for the losing bidder getting the rules changed. And now using trade wars to harm Airbus.

    If they spent as much effort aa they do gaming the system on designing and building aircraft, this would never had happened.
     

Share This Page

arrow_white