Another Boeing 737 Max-8 crash

Discussion in 'General' started by SPL170db, Mar 10, 2019.

  1. speedluvn

    speedluvn On a Quest For Speed

    From my understanding, the world's leading authority on air crash investigation is the NTSB and BEA (French) and often times countries will invite them to assist or observe the investigation.
    BigBird likes this.
  2. HPPT

    HPPT Admin/Mod

    It's entirely up to the people who have jurisdiction, from what I understand.
    Even for a Boeing, there is no requirement for the NTSB to be there unless they are invited. They have no jurisdiction over there.
    The black boxes are at the BEA right now.
  3. Hooper

    Hooper Well-Known Member

    From American Airlines website:

    "American has flown more than 2.5 million passengers — during 46,400 operating hours encompassing nearly 18,000 flights — safely on our MAX 8 fleet since the first one was delivered Sept. 2017 and began commercial service later that November."

    That looks like quite a while too me.
  4. HPPT

    HPPT Admin/Mod

    That's not a good record for a modern aircraft.
  5. ChemGuy

    ChemGuy Harden The F%@# Up!

    I have also read an a couple of US flights pilots had issue with uncommanded pitch changes.
    Sounds like a hardware(sensor) or software issue may be causing of these pitch issues. Hopefully they figure it out and fix it asap.
  6. Hooper

    Hooper Well-Known Member

    Southwest Airlines is reporting more than double those hours and flight numbers with their Max 8 fleet with "no safety concerns being reported". I just think that seems to lend some credence to the lack of training and/or experience of the pilots on the doomed flights being a major contributor to the crashes.
    Last edited: Mar 14, 2019
    Jay305 likes this.
  7. HPPT

    HPPT Admin/Mod

    I heard on TV that one of the pilot reports after one of those incidents in the US last year described the flight training manual as "criminally insufficient."

    Here, I found an article that quotes it.

    If you fly the airplane by the book, and the book is inadequate, I'd say the manufacturer shares a large chunk of the responsibility.

    Anyway, we don't know what happened on this flight yet. The industry has historically leaned towards caution in these situation. You can find examples from the deHavilland Comet to the 787 Dreamliner.
  8. SteveThompson

    SteveThompson Banned by amafan

    Yet here we are... on post #228. :D
    _indy, ChemGuy and HPPT like this.
  9. Monsterdood

    Monsterdood Well-Known Member

    Yes, there is an Air Worthiness Directive which states that a failure of the angle of attack sensor can result in these pitch issues. The mitigation is to flip the trim cutoff switch and manually trim with the wheel and that’s a poor architecture. Especially when you didn’t put that explicitly in the manual originally and didn’t train for that scenario.

    They will decrease the authority of the MCAS, likely change the behavior in a single sensor fault scenario (alerting and automatic disabling) and make it so that you don’t have to flip the cut off switch to avoid a crash. Basically they have a switch you HAVE to flip to avoid crashing if a single sensor fails. That has to change and will change ASAP [captain obvious here].
  10. dieterly

    dieterly Well-Known Member

    Are you saying there’s no need for the cutoff switches after Boeing fixes the MCAS issue?
  11. SPL170db

    SPL170db Trackday winner

    Well, either way, I guess I'm glad my flight next week is on an "old" 737-900 then.
  12. Monsterdood

    Monsterdood Well-Known Member

    No, I think you would keep the cutoff switches for sure, but the new software should ensure that the cutoff switch is not needed to maintain safe control and authority over the pitch axis. Right now, the cutoff switch stops a slow runaway, and they need to decrease how far a slow runaway condition can go so that the column/elevator maintains sufficient authority to override an erroneous MCAS trim.

    Even more robust would be developing a dual channel AOA sensor with integrity monitoring that would automatically deactivate the system in a failure condition. I suspect that is too much architecture change at this point and the fix will be more on the software side with the manual cutoff mitigation remaining.
    busa99 likes this.
  13. Photo

    Photo Well-Known Member

    Boeing just bought fore flight on march 6th 2019.
  14. worthless

    worthless Well-Known Member

    Data storage is cheap. Satellite comms are already in place. I would think that the cost could be easily justified. Don’t know if there’s any way to calculate how much, but, I’m pretty sure this global grounding is costing some serious $. I get it that the risk of not being able to recover the data is low, but, it can and has happened and an electronic data logging would provide much quicker access to the data. They would not only have immediate access to the data, but, they could also have a database of past flights so they could compare data to possibly come up with possible causes. There have been reports of other pilots reporting similar issues, but, they were able to pull out of it. With electronic data logging and a history, they’d be able to look back at those incidents to see if they’re related. I have a feeling that the biggest fight would be over ownership of the data.
  15. Motofun352

    Motofun352 Well-Known Member

    The best analysis I've heard (still speculation at this point in time) is that in order to haul the bigger payload, They needed bigger engines. In order to fit the bigger engines they needed to relocate them lower that, in turn, changed the center of lift and the dynamics of the aircraft as it approached a stall condition. The electronics package is intended to prevent approaching this stall condition. If it's so bad that properly trained pilots can't control it I'm not sure that Boeing can eliminate the MCAS. Perhaps the airframe is just being asked to do too much?
  16. Motofun352

    Motofun352 Well-Known Member

    On another note, I'm not a frequent flier but I have been on flights where I was impressed with how fast the pilots would climb out and away from some airports. Is air traffic perhaps getting so congested that has become normal to climb steeply away? This would explain why there is a concern about approaching stall conditions.
    joec likes this.
  17. speedluvn

    speedluvn On a Quest For Speed

    Or noise restrictions around the airports?
  18. G 97

    G 97 What's my name

    Any guesses on the time frame to determine what happened? I would think by now, given if they have all of the data recordings, they have a pretty good idea of what exactly happened, at least as far as what the data is showing.
  19. speedluvn

    speedluvn On a Quest For Speed

    6-9 months for the public to be made aware. 45 days to 3 months for insiders to be informed. Just my guess.
  20. G 97

    G 97 What's my name

    Which also brings up another question. If you design and manufacture a plane that has to rely on a “computer program” to help avoid or avoid altogether a certain type f event outside of what they think the pilot is capable of doing, why keep the design? If you are that concerned with certain performance habits/events. At the very least, make it known to all pilots and carriers so they can provide adequate training etc.

    Way to early but as of now, pitch forks and 3 foot screw driver for Boeing. :D

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