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Thread: Breaking news: Ethiopian Airlines flight has crashed on way to Nairobi

  1. #221
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    This is from todays AW newsletter:
    A point of clarification we have reported previously that I should have included in the original story above: while the Maneuvering Characteristics Augmentation System (MCAS) is not triggered via pilot input, it is only active during manual flight with flaps up.
    Thought it might of interest to some of you.

  2. #222
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Highkeas View Post
    This is from todays AW newsletter:
    A point of clarification we have reported previously that I should have included in the original story above: while the Maneuvering Characteristics Augmentation System (MCAS) is not triggered via pilot input, it is only active during manual flight with flaps up.
    Thought it might of interest to some of you.
    Yes, we already mentioned that earlier. And even then, in manual flight with flaps up, "active" is perhaps not the best term. It is armed but doing nothing under normal conditions, unless certain parameters are abnormally exceeded (or there is a single sensor failure sending incorrect information for one of those parameters).

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    Quote Originally Posted by Gabriel View Post
    Only yesterday the Ethiopian authorities requested BEA's help to read out the CVR and FDR, and BEA accepted. They might just arrived to BEA or even be on their way at this moment.

    The Canadian authorities did not have any information on the contents of the recorders when they took the decision, and neither did Trump or the FAA.
    The FAA and the Canadians did apparently have information from the Aireon ADS-B satellite tracking system. This was the "additional information" the Canadians mentioned yesterday, which led them to ground their Max airframes, and subsequently the US as well. The data seemed to confirm that the flight characteristics of the Ethiopian were very similar to the Lion Air. I have no idea how credible this is.

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    Okay I am sure you have been inundated but tell me what you know about MCAS and if you think this is what caused either of the two

    Sup, yes, I think it definitely causes the accidents, at least the Lion Air. The MCAS pushes the nose over when aircraft thinks it’s stalling to help break the stall. So those guys had a failed airspeed indicator and the airplane thinks it’s stalling, so it trims down, even with auto pilot off. These guys are crashing them in VMC, imagine getting this in IMC.

    No way to disconnect the system?

    The worst part, the most fucked up thing, is that Boeing put the system in the aircraft and did not tell the companies, pilots, maintenance, put in the manuals. We had no idea the system was even installed until the Lion Air crash.

    Yes, you disconnect the trim, like a runaway stabilizer.

    So now you’re manually flying it, manually trimming the aircraft, with no air speed indication.

    Have you flown the max?


    Yes. Also, you have to recognize this problem, when you have a loss of reliable airspeed. Which is a handful to begin with.

    This is what I got from my friend who is a Captain at Southwest.

  5. #225
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    Quote Originally Posted by BoeingBobby View Post
    So now you’re manually flying it, manually trimming the aircraft, with no air speed indication.
    Also, you have to recognize this problem, when you have a loss of reliable airspeed. Which is a handful to begin with.
    Again, I think this is key to understanding the apparent pilot error we are seeing. Scrambled situational awareness. Human factors.
    Thanks for posting that.

  6. #226
    Senior Member 3WE's Avatar
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    Quote Originally Posted by BoeingBobby View Post
    […]

    you disconnect the trim, like a runaway stabilizer.

    So now you’re manually flying it, manually trimming the aircraft, with no air speed indication But with a perfectly OK attitude indicator, right?...nose down ain't good...Actually, to recite the light plane version- Use the control yoke to maintain the proper attitude and trim to remove the control forces..
    […]
    Acknowledgement- your slick powerful aeroplanies might overspeed a lot faster that I imagine- yes, I have no 737-Minlav time and yes trim is more than just a force reliever on transport jets...still, the broad procedure has reasonable applicability, yes?

    Although- the comment: No notification/Nothing in the manuals (Combined with Evan's list of how you can over-ride the autopilot vs. how you cannot override this MCAS stuff...and only one single sensor signals you are near-stalling...sure seems to go against common sense).
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    Quote Originally Posted by birdguts View Post
    maybe plane hacking? 3 boeings in 1 year? that's crazy
    Um, no.

  8. #228
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    Quote Originally Posted by Evan View Post
    So you think that Lion Air didn't promote their brand new MAX fleet to potential customers as a brand asset and an indicator of progressive (and thus safe) brand values?

    Sure, there are those who ONLY look at price, but I think many people who are flying to marginal parts of the world or on low cost carriers ask themselves the safety question. "What is Lion Air? Never heard of them... Are they safe to fly on?" And then they might ask around or go to the airline website. A brand new fleet of Boeing's latest, cutting-edge 737's is certainly going to make them feel better about that mystery airline. In fact, I think it might make them feel completely confident. I have friends who ask me about particular airlines when travelling in dubious parts of the world. Ironically, one of them asked me about Ethiopian several years ago. She was seriously concerned. I reassured her that they were considered one of the safest options...
    of course, you would have a deflective answer.

    i can tell you that i havn't seen much in the way of marketing those sardine cans in the US. they absolutely suck donkey-ass from a confort perspective. even biz class lost 5 inches of pitch. "OOOOOOO we have the boeing 800MAX(discomfort) come check out our torture chambers for the same price you paid for a seat on a far more comfortable (and safer) NG."

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    What we all seem to be forgetting here is that in BOTH cases it appears that neither aircraft stalled. MCAS performed flawlessly!

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    Quote Originally Posted by vaztr View Post
    What we all seem to be forgetting here is that in BOTH cases it appears that neither aircraft stalled. MCAS performed flawlessly!
    [sarcasm: off]

    Did the pilots know that the plane did not stall? I have been having second thoughts in the last few hours. With he AoA that was being indicated in the Lion Air crash, I would expect the sticksahker to be shaking. Picture a scenario where the airspeed crap, the stick shaker activated, and the plane is pitching down by itself. Is it stalling or what? I can picture a scenario where the avalanche of seemingly contradictory and apparently nonsensical information can overwhelm the pilots' brain.

    I suppose that it is time to wait for at least the interim report of the Lion Air crash to at least have a clearer picture of what the pilots faces and what transpired in that cockpit.
    As for the Ethiopian one... I guess we need to wait for ANY factual information beyond what it is publicly known today to make any informed speculation.

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    Quote Originally Posted by HalcyonDays View Post
    The FAA and the Canadians ... have information from .. ADS-B ... The data seemed to confirm that the flight characteristics ... were very similar to the Lion Air. I have no idea how credible this is.
    Confirmed by Elwell last night (#187) and again this morning (link below). He also referred to corroborating "evidence we found on the ground".

    https://arstechnica.com/information-...oeing-crashes/

  12. #232
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    Quote Originally Posted by flashcrash View Post
    He also referred to corroborating "evidence we found on the ground".
    I can only think of that being evidence of flaps retracted and stabilizer fully nose-down.

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  13. #233
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    Quote Originally Posted by Gabriel View Post
    ***Did the pilots know that the plane did not stall? I have been having second thoughts in the last few hours. With he AoA that was being indicated in the Lion Air crash, I would expect the sticksahker to be shaking. Picture a scenario where the airspeed crap, the stick shaker activated, and the plane is pitching down by itself. Is it stalling or what? I can picture a scenario where the avalanche of seemingly contradictory and apparently nonsensical information can overwhelm the pilots' brain.***
    Edit: Upon further review- it's not clear: Was Lion Air getting a stick shaker, or was it "just" airspeed problems + nose over? You may adjust my "tip the scale" comments however you see fit.

    Objective: Pure discussion- no strong statements of disagreement.

    Along with your thoughts was a comment from Dummy Pilot long ago- that Swept Wing airliners ease into stalls...no real buffet/break...you may not realize WHEN you are stalling.

    Based on all of our parlour talk on the importance of a little nose over...you may really have hit on something that "wow, maybe the plane IS stalling" cuz I WAS going a LITTLE slow and now I don't have Airspeed...but crap, it doesn't seem to be recovering, I GUESS we could be like AirFrance in a reasonably level attitude, but mushing downward.

    Ok, in a perfect world YOU MAINTAIN ATTITUDE during this MCAS push over....the attitude IS what it SHOULD be, the power IS what it SHOULD be, the airspeed WAS what it SHOULD have been and the VS IS what it SHOULD be, I felt NOTHING else that SHOULDN'T be...

    You have to have that tip the scale on "wow, maybe? the airplane is pitching over in a stall". I want to belive the evidence is much heavier that you aren't stalling and that your AOA never varied from a healthy value because you were flying the GD plane (or at least monitoring it like a hawk).

    Stupid question-do you get ANY other indication of stall other than I wasn't flying super fast and the nose is dropping?

    Now, back to a most touchy subject...there is almost no practice of FULL STALLS in airliners (For one they can be dangerous- CRJ's like to flame out, T-tail aeroplanies may deep stall, yada yada yada...so I'm not sure that current transport pilots have any idea what a stall SHOULD feel like...

    ...Your time is BETTER spent never getting anywhere CLOSE to a stall WARNING (and then IMMEDIATELY addressing the WARNING (with a full-performance climb out))
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  14. #234
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by 3WE View Post
    Stupid question-do you get ANY other indication of stall other than I wasn't flying super fast and the nose is dropping?
    Saltshaker, mushy controls, loss or roll authority and stability (that causes or tends to cause roll PIO), a sink rate that looks too high for the pitch... and buffeting.

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  15. #235
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Gabriel View Post
    Saltshaker, mushy controls, loss or roll authority and stability (that causes or tends to cause roll PIO), a sink rate that looks too high for the pitch... and buffeting.
    Sorry- I phrased my question wrong...

    Did the Lion Air pilots get any other indication of a stall other than the nose dropped and they were a tiny bit slow (meaning climbing or low altitude vs high-speed cruise).

    It's not clear in your original comment if they received "official" stall warnings.

    Just because I believe in the max performance incipient stall recovery (except don't do it mindlessly) doesn't mean that I don't know the characteristics of a stall- it's not something the chief instructor at SMRFSDN needs to be lectured on.
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  16. #236
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    Quote Originally Posted by 3WE View Post
    Sorry- I phrased my question wrong...

    Did the Lion Air pilots get any other indication of a stall other than the nose dropped and they were a tiny bit slow (meaning climbing or low altitude vs high-speed cruise).

    It's not clear in your original comment if they received "official" stall warnings.

    Just because I believe in the max performance incipient stall recovery (except don't do it mindlessly) doesn't mean that I don't know the characteristics of a stall- it's not something the chief instructor at SMRFSDN needs to be lectured on.
    In my previous previous last post I was speculating that perhaps the stickshaker, since one of the AoA sensors was providing a way-too-high AoA .

    I will pass your feedback to the headquarters of SMRFSDS.

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  17. #237
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    Quote Originally Posted by Gabriel View Post
    Did the pilots know that the plane did not stall? I have been having second thoughts in the last few hours. With he AoA that was being indicated in the Lion Air crash, I would expect the sticksahker to be shaking. Picture a scenario where the airspeed crap, the stick shaker activated, and the plane is pitching down by itself. Is it stalling or what? I can picture a scenario where the avalanche of seemingly contradictory and apparently nonsensical information can overwhelm the pilots' brain.
    I think you are beginning to see the light! Loss of autoflight (if it was ever engaged), UAS, AoA disagree warnings, Altitude disagree warnings, stickshaker and a FEEL DIFF PRESS warning are all expected consequences of an erroneous AoA input. That plus uncommanded pitch excursions. Nuts!

    You can't just expect pilots to correctly deal with that situation as your ONLY redundancy.

    I still suspect that the system was supposed to compare inputs, detect the AoA anomaly and rule it out, but didn't work as designed. (See: Turkish 1951, specifically the DSB report, appendix Q)

  18. #238
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    Quote Originally Posted by Gabriel View Post
    I was speculating that perhaps the stickshaker, since one of the AoA sensors was providing a way-too-high AoA.
    Teeth-clenched-head-nod emoji that your unsubstantiated speculation at what's on the thought process recorder is kind of plausible...
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  19. #239
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    Quote Originally Posted by Evan View Post
    ***Altitude disagree warnings***
    Time out...

    I thought a key complaint was that there was only ONE thingie that triggered the ELCAS (plus the crappy, inconsistent auto disconnect mechanisms).

    Now you are saying: Speed was off, AOA was off Altitude was off AND some goofy thing in the rear differential between the axles and drive shaft has low oil pressure....

    (Gabriel, please do not explain the sensors that provide AOA, airspeed, altitude and VS readings- they are different thingies towards the front of the plane- yes it's part of the Del Norte curriculum.)
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    In a prior post I wondered what the flight history was for US airlines 737Max aircraft.
    I just received a public relations email from SWA that contains some flight history:
    34 aircraft
    40,000 flights
    90,000 flight hours

    That "averages" 1,176 flights per aircraft.

    No details on any inflight upsets.

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