Boeing - Design Issues...

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

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  1. Oct 22, 2019 #301

    davidb

    davidb

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    The HSTA failed on a MD-83. Boeing ordered inspection of all similar HSTAs of Boeing aircraft. One 757 had corrosion. All Boeing HSTAs now get routine inspections and preventive maintenance. I’d say that’s pretty good proactive risk management since I’m not aware of any HSTA failures on Boeing aircraft.

    The Max now has an additional comparative computer that samples both AoAs as well as other inputs before it directs MCAS to move the trim. Trim movement is much more restricted on the redesign. Problem solved. I’m hearing the FAA is ready to sign off the redesign and put the Max back in service. The holdup now is most other countries are resistant. Feel free to speculate on motives for either. As an operator, I’m completely comfortable flying even the original design of the Max.

    What I am not comfortable with is knowing the world has thousands of pilots who could have handled the malfunctions safety and thousands of pilots who may have suffered the same fate. We need to effectively train for the known and unknown. And, there needs to be a global standard.

    I laud the FAA for upping experience minimums and putting a renewed emphasis on hand flying as well as fundamental aircraft control. For too long, training was focused on management of all the new automation. Until we remove the sticks, yokes, rudder pedals, and thrust levers from the cockpits...pilots should know how to use them. All pilots. Why the world accepts a 300 hour computer operator in the right seat is beyond rationale. The most important piece of equipment should have redundancy and reliability.
     
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  2. Oct 23, 2019 #302

    Wanttaja

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    According to the Seattle Times, this was probably an issue with the simulator itself, not the flight control logic.

    "The bottom line is that the erratic behavior described in the 2016 chat by 737 MAX chief technical pilot Mark Forkner revealed a software bug in the MAX flight simulator he was using, a pilot training machine that he and his colleagues were then fine-tuning to get it ready for the MAX’s entry into service.

    It was not evidence of the flaws that later showed up on the real airplane’s new flight-control system — known as the Maneuvering Characteristics Augmentation System (MCAS) — that caused the fatal crashes of the jets in Indonesia and Ethiopia."


    https://www.seattletimes.com/busine...sed-erratic-behavior-cited-in-pilot-messages/

    Ron Wanttaja
     
    Last edited: Oct 23, 2019
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  3. Oct 23, 2019 #303

    Himat

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    The trouble the FAA now have among other things is damaged reputation and lack of trust. Combined with politics, expect Boing to have to prove their design direct to European and Chinese authorities.

    Politics again, the FAA’s role to set worldwide standards are contested. Other regulating bodies may have different views. Differences in home market technology, business and culture may shape regulatory bodies view to favour own. This is a convenient opportunity to those who want to chip away at USA’s ability to define rules applicable to the world.
     
    Last edited: Oct 23, 2019
  4. Oct 23, 2019 #304

    flyboy2160

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    davidb, I have applauded your astute comments on this issue, save this one.

    It's unworkable. Who sets the standard? Some global commission? The UN? It would be FUBAR from the get go.

    It's not needed. For too long technically illiterate flying customers just assumed 'somebody is taking care of this.' Well, let flying customers become aware that safety and training standards vary across the globe. Do you want to pay extra to get Western trained pilots and maintenance crews or put up with locals from a country that has faith-based car repair shops? Let the airlines use their safety records and standards as a selling point in advertising in addition to puffball, feel good, la-la-la lightweight ads.
     
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  5. Oct 23, 2019 #305

    Vigilant1

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    And yet, here we sit in the US with all the 737MAX jets grounded. Why is that? Yes, the software can be improved (and that's happening), but there is a >very< strong case to be made that crews trained to a certain standard can fly the plane very safely. There have been no crashes attributable to the MCAS among western airlines. So, when planes crash in Africa or Asia, the public demands (and FAA agrees) to ground airliners flown by US crews.
    The 737 has a very good safety record. If we look at the record from 1959 through 2017 (the most recent I could find) hull-loss-rate with fatalities per departure rate for the 737-600 through 900s is commendable. If we compare their loss rate to other planes with statistically significant service periods (one million departures ar greater), the fatal accident rate for those 737s over that time period is less than 1/2 the rate of the 777s, 767s, 757s, A-300s, A-310s, and A-330s. In US service there has never been a fatal crash involving a 737 Max (but the service history is short). If US passengers who would have been on 737 MAX aircraft over the last year were instead put on other aircraft, or especially if they drove on the highway, they were probably at significantly greater risk than if they'd been aboard a 737 Max operated by a US carrier.

    upload_2019-10-23_18-3-18.png
     
    Last edited: Oct 23, 2019
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  6. Oct 24, 2019 #306

    plncraze

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  7. Oct 24, 2019 #307

    davidb

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    For the record, I realize there will never be a global agreement for safety driven standards and regulations. Economics certainly won’t drive an increase of safety. It’s hard to quantify and put a price premium on increased safety. You can’t market it like increased leg room.

    Perhaps global standards are unworkable but it is needed. We’ve seen airlines with atrocious safety records survive consumer scrutiny by simply changing their name.
     
  8. Oct 24, 2019 #308

    flyboy2160

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    We'll just have to agree to disagree. What I see as workable is a private, consumer advisory rating service that lists the safety records, training, and maintenance requirements of airlines in a manner that's digestible to the flying public.
     
  9. Oct 24, 2019 #309

    litespeed

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    But a consumer info led system is rife for abuse of marketing.

    Why should the consumer have to make a guess about if they are safe or not?
    Yes, publication of the stats is fine but that is not a solution to safety.

    The responsibility lies with regulation. Unregulated leads to a dog eat dog race to the bottom.

    Reducing active regulation and compliance is what got Boeing into this disaster.

    A few comments seem to find any argument to excuse Boeing and just blame the pilots. Or the Country flying it or the passengers for not flying American crewed flights.

    Lets get real and accept "Until proven otherwise" the Aircraft is manifestly to blame and its maker. The problem is so apparent, some seem unable to see it on the end of their nose.
     
  10. Oct 24, 2019 #310

    davidb

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    I just googled “airline safety records” in hopes of finding useful information like you describe. There is certainly no shortage of sites to peruse. IMO, they are useless. The various methods of ranking airlines’ safety all seem flawed. How would you ensure bribery and corruption couldn’t influence the ratings?

    It just seems impossible to objectively rate and rank safety. I could meaningfully assess the training and safety culture of an airline if I were hired, trained and employed with them for a year but I can’t do that for all airlines.
     
  11. Oct 24, 2019 #311

    Vigilant1

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    Thanks for the post. That article by Langeweische (direct link here) is the most thorough, accurate, and evenhanded account I've seen of the two accidents and the situation that led to them (at Boeing and the airlines). I don't agree with every line, but it's clear that someone who knows what he's talking about has done some good research--that's what journalism should be.
     
  12. Oct 24, 2019 #312

    davidb

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    That’s good to know should I ever run over a pedestrian with my automobile.
     
  13. Oct 24, 2019 #313

    flyboy2160

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    The method used by the private company, Underwriters Laboratory (UL), that certifies and labels many consumer electronic products: they realize that they will be out of business if they are corrupt because their label would mean nothing. (I went through getting UL approval for a consumer electronic device and asked them this very question.)

    Lolololol And we all know that government agencies are just automatically corruption and fraud free.

    To be clear, I'm NOT advocating doing away with the FAA. I want some way of judging whether some other countries' standards are any good. How do the Ethiopian or Malaysian equivalents of the FAA stack up against the FAA? I mean some of you already complained about the lack of training of the Max crash pilots.
     
    Last edited: Oct 24, 2019
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  14. Oct 24, 2019 #314

    Vigilant1

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    I understand and am sympathetic to your position. (For a semi-related point, see Milton Friedman's case against the licensure of physicians). Unfortunately (IMO), there's no chance that the public will accept the idea of shopping for airline safety as they would shop for other commodities ("Want a safer trip? Buy a ticket from a safer carrier. The private rating agencies give grades publicly.") From banks to food to cars to air travel, the public wants the government involved in setting standards and enforcing them.
     
  15. Oct 24, 2019 #315

    BBerson

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    The Boeing 737 Max Emergency Airworthiness Directive assumes the AOA sensor vane was defective in the Lion Air crash and simply warns the pilots to use a procedure to turn off the trim switches. But simply assuming the AOA was defective is illogical with no evidence. (see Langweishe article in New York Times)
    Logic would say that odds of three defective AOA sensors is unlikely (two at Lion Air and one on Ethiopia crash)
    If three AOA sensors were defective then someone should be inspecting AOA sensors in the fleet.
    It's far more likely something else was at fault. Mechanics often install new parts. If that doesn't fix it on the next flight such as happened with Lion Air, then that part likely wasn't the fault.

    quote from Langweishe article:"The MCAS as it was designed and implemented was a big mistake".
     
  16. Oct 24, 2019 #316

    Vigilant1

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    The AoA sensors do have a relatively high failure rate. They are sensitive mechanical devices that fail internally, get bumped by ground equipment, hit by birds and shedding ice, etc. The plane has redundant, independent AoA sensors and displays, and it has (traditionally) been part of the normal procedures and airmanship expected of crews to cross-check differing AoA readings. If only one stick shaker is going off, that's a very clear indication that at least one AoA sensor is wrong. That's exactly what happened on both of these flights. And it's pretty clear that Lion Air mechanics didn't actually fix and confirm the proper operation of the faulty AoA sensor (it had been bad for at least a few legs).

    Now, it would have been better if the MCAS had, from the start, used better logic to assure it was using the "best" AoA source OR if it had been designed to deliberately notify the crew of a conflict in the AoA readings on both sides of the plane. But, if crews demonstrate the degree of systems knowledge and fundamental airmanship that has traditionally been associated with commercial aviation, this would not be strictly required. The signs of disparate AoA indications/ a faulty AoA vane are clear, and the proper actions are also not difficult to implement--for crews trained to the traditional standards.

    Was MCAS, as it was designed and implemented, a big mistake? Clearly, if we judge from the impact this has had on Boeing, and on the lives lost in these two crashes, it was a big mistake--as it was implemented.
     
    Last edited: Oct 24, 2019
  17. Oct 24, 2019 #317

    BBerson

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    Unless they still have that two month old AOA vane they removed laying around to test, nobody knows exactly that it was defective.
    I read Boeing thought the chance of failure was quite high (one per billion or something) so they assume one was enough. But any defect in the AOA circuit could trigger the disaster, not just the AOA vane. In fact, since the replacement didn't change anything I would assume another fault.

    I really don't want to fly in this Max until some actual fault is found. And neither do others I talk to.
     
  18. Oct 24, 2019 #318

    Vigilant1

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    What do you find deficient in the explanation of the crashes as provided by Langweishe? It is consistent with the known information from the flight data recorders, from the information provided by radar, with the maintenance and flight history of the aircraft, and it can be replicated in the simulator. We know that some previous crews did a poor job of writing up the known faults in the aircraft when they left the planes, and that at least one previous flight of one of the same planes suffered the same problems and averted a tragedy when one (jumpseat) pilot applied proper published procedures for runaway trim (disconnect of the electric trim, use manual trim wheels).
     
  19. Oct 24, 2019 #319

    BBerson

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    If the fault was the three defective AOA vanes then why hasn't someone looked at the AOA company that makes them?
    As Langweishe said, these countries are not providing all the info. The primary cause of these MCAS disruptions has not been disclosed yet. I don't think Langweishe explained exactly why MCAS failed.
    The AD didn't help prevent the second crash either.
    So what's taking so long to announce what part was defective?
     
  20. Oct 24, 2019 #320

    litespeed

    litespeed

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    Well, you would if the new model car was banned from driving anywhere in the world, until they figured out why the computer chooses to " keep defaulting to 'Run over pedestrian' mode".

    That is the auto equivalent.
     

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