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

  1. #241
    Senior Member Gabriel's Avatar
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    I though that I had seen that somewhere. It is there in the official interim report. Both Lion Air flights (the one previous to the crash and the crash one) had stickshaker shaking from rotation and throughout most of the flight.

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  2. #242
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    Quote Originally Posted by Gabriel View Post
    I though that I had seen that somewhere. It is there in the official interim report. Both Lion Air flights (the one previous to the crash and the crash one) had stickshaker shaking from rotation and throughout most of the flight.
    Stickshaker was most definitely on for most of the Lion Air fligt. I know this because a guy named Gabriel posted this
    https://forums.jetphotos.com/showthr...l=1#post674174

    Direct link - see graphs
    https://avherald.com/h?article=4bf90724&opt=0

    Click image for larger version. 

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  3. #243
    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    I though that I had seen that somewhere. It is there in the official interim report. Both Lion Air flights (the one previous to the crash and the crash one) had stickshaker shaking from rotation and throughout most of the flight.
    Yes, and to make it just slightly more confusing, only on the one side.

  4. #244
    Junior Member HansPeter's Avatar
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    Regarding the Lion Air fligt data from my last post.

    One thing I would like views on/I don't fully understand in the Lion Air flight data is the 'CCFORCE_PITCHCWSLOCAL' and CCFORCE_PITCHCWSFOREIGN'.

    During most of the flight 'local' and 'foreign' follow each other but at the end 'foreign' goes way above anything seen earlier in the flight. It is followed by an even more aggressive 'local' until the end.

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    Quote Originally Posted by Evan View Post
    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)
    I find that to be a very interesting conjecture. In other words, the so-called "software enhancement" proposed by Boeing might just be about making the software work the way it was supposed to work in the first place?

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    This article has a nice visual of the two satellite plots that the US and Canadian authorities were using: https://www.theglobeandmail.com/opin...define-safety/

  7. #247
    Senior Member Evan's Avatar
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    Quote Originally Posted by flashcrash View Post
    I find that to be a very interesting conjecture. In other words, the so-called "software enhancement" proposed by Boeing might just be about making the software work the way it was supposed to work in the first place?
    Wouldn't be the first time.

  8. #248
    Senior Member Evan's Avatar
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    New York Times reporting that the pilot requested a return after three minutes in a panicked tone of voice. They are also reporting that it "accelerated to abnormal speed". It also apparently turned back while in a climb.

    I get the impression it was never stabilized on autoflight. But why the speed?

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    If I understand this correctly, MCAS was introduced because the new 737 MAX with its bigger engines had a tendency to pitch up in certain circumstances. In fact, it's been reported that the plane would not have received certification without this software add-on. However, when MCAS goes on the blink we are led to believe that the solution is for the pilot to disable it, take over and fly the bloody thing. If the pilot can be relied on to do this in an emergency situation, why is MCAS there in the first place? At the same time, MCAS only kicks in when the 737 is being flown manually. Typically, this is most likely at a low altitude. So this "helpful software"when things go wrong can throw up distractions and potential confusion at the precise moment when only seconds are available to sort it out.
    Crazy or what?

  10. #250
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    sensor error readings rendered autopilot unusable, while on switching to manual mode the MACAS starts to kick in which confuses the pilot. plus pilots used to drive 737 plane previous to the MAX model which requires different skills to recover the airplane might be the cause of the accidents imho.

  11. #251
    Senior Member Evan's Avatar
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    Quote Originally Posted by pegasus View Post
    However, when MCAS goes on the blink we are led to believe that the solution is for the pilot to disable it, take over and fly the bloody thing. If the pilot can be relied on to do this in an emergency situation, why is MCAS there in the first place?
    Excellent point. MCAS is provided to compensate for pilot error, yet the ONLY redundancy provided for a single point sensor failure is flawless pilot response. Irony.

    Crazy or what?
    No, I think this is just a developmental flaw in a rushed process with insufficient testing. I think it was designed to be redundant but didn't work as designed. However, the initial response from Boeing, that the system is safe simply because pilots have a shutdown procedure, is nuts.

  12. #252
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    Quote Originally Posted by Gabriel View Post
    [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.

    Pretty sure stickshaker was mentioned as one of the things the Lion Air crew were dealing it - I remember it for at least one of the flights, but probably it was on all of them. There was a lot going on, and that's why I said I thought the crew that didn't crash almost got kinda lucky. Or they were just really good at CRM and had more experience. A combination of factors, probably.


    EDIT: never mind, I see stickshaker has been confirmed.

  13. #253
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    Quote Originally Posted by pegasus View Post
    If I understand this correctly, MCAS was introduced because the new 737 MAX with its bigger engines had a tendency to pitch up in certain circumstances. In fact, it's been reported that the plane would not have received certification without this software add-on. However, when MCAS goes on the blink we are led to believe that the solution is for the pilot to disable it, take over and fly the bloody thing. If the pilot can be relied on to do this in an emergency situation, why is MCAS there in the first place? At the same time, MCAS only kicks in when the 737 is being flown manually. Typically, this is most likely at a low altitude. So this "helpful software"when things go wrong can throw up distractions and potential confusion at the precise moment when only seconds are available to sort it out.
    Crazy or what?

    This story discusses the history of the 737 aircraft https://www.msn.com/en-us/travel/new...cid=spartanntp

  14. #254
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Black Ram View Post
    ***the crew that didn't crash almost got kinda lucky. Or they were just really good at CRM and had more experience. A combination of factors, probably.***
    Exactly WHEN HAL goes Y2K probably has a big influence.

    If you are crusing along fat, dumb and happy at mach point something and with 30K feet of altitude to burn- it may be easier to say, "the computer is [naughty word] let's keep flying at healthy attitude and power settings"

    Conversely, you are taking off- with the nose pointed WAY in the sky and flying a little bit slow and airspeed goes away and a stall warning goes off and you have 2000 feet to play with...

    Dare I say that you are behind on the comprehension curve with less buffer to work out of some really dire warnings...

    (Not to say that another crew on another day might have persevered (should have?)...but also, we are hearing that this isn't something you "trained on" either.)

    With several of my bicycle crashes the time between fat dumb and happy and too-late-to-do-anything is pretty quick.

    Conversely- with Lion air, the question if tough- they seemed to be managing things OK for a few minutes and then "just" dove in...

    IF this crash is related, these guys did have a shorter time to work through things.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  15. #255
    Senior Member Evan's Avatar
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    Was hoping to get some further clarity today on the abnormal speed issue.

    What would cause a speed 'runaway'? EEC? Not on both engines at the same time. Unless... something... else... got... left... out of... the... manual,,,

    No idea, really. Boggling development.

  16. #256
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Evan View Post
    ***What would cause a speed 'runaway'?***
    Can you clarify?

    My first reaction is "leveling off at high power settings" or "the push-over from MCAS while at high power settings".

    (Sarcasm level is only at 20% here- my understanding is that these planes were both in takeoff/climb out types of settings where traditionally you might need to throttle back if you level off...and the MCAS is supposedly pushing them over while they are not getting airspeed data- I want to believe that Bobby would throttle back the exact right amount, but I also have sympathy for confusion when your computer AND the airplane BOTH go crazy).
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  17. #257
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by 3WE View Post
    Exactly WHEN HAL goes Y2K probably has a big influence.
    The stickshaker started as soon as they rotated. The MCAS push down started as soon as they retracted the flaps. In both Lion Air flights.

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  18. #258
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Gabriel View Post
    stickshaker...rotated...both Lion Air flights.
    10-4....and wow- forgot that and just ASS umed it went off somewhere in -flight.

    Credit crew 1 with "continuing to fly the GD airplane" vs. Crew 2 who at some apparently let it have its way.

    Foul on crew 1 because I'd THINK you want to promptly turn around and land (while continuing to fly the GD airplane).

    (And yes, foul on them? or the whole airline? for not reporting and fixing it overnight).
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  19. #259
    Senior Member Evan's Avatar
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    Quote Originally Posted by 3WE View Post
    Can you clarify?

    My first reaction is "leveling off at high power settings" or "the push-over from MCAS while at high power settings".
    That's actually what I thought at first. Because apparently the flight was initially flying below MSA. But...

    Quote Originally Posted by NY Times
    Then the controllers observed the plane going up and down by hundreds of feet, and it appeared to be moving unusually fast, the person said.
    Flight 302 was just three minutes into its flight, the person said, and appeared to have accelerated to even higher speeds, well beyond its safety limits.
    By 'well beyond its safety limits', should we assume they mean overspeed, as in, Vne?

    This 'person' is apparently one of the flight controllers. However, I afford at least 50% speculation to lost-in-translation or daft-media-reinterpretation.

    But then...
    Quote Originally Posted by NY Times
    “The speed is very high,” said Mr. Cox, a former executive air safety chairman of the Air Line Pilots Association in the United States. “The question is why. The plane accelerates far faster than it should.”

  20. #260
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by 3WE View Post
    10-4....and wow- forgot that and just ASS umed it went off somewhere in -flight.

    Credit crew 1 with "continuing to fly the GD airplane" vs. Crew 2 who at some apparently let it have its way.

    Foul on crew 1 because I'd THINK you want to promptly turn around and land (while continuing to fly the GD airplane).

    (And yes, foul on them? or the whole airline? for not reporting and fixing it overnight).
    According to the interim report, this is what crew 1 did (it sounds like a good job overall but nothing heroic or super difficult):

    - On 28 October 2018, a Boeing 737-8 (MAX) aircraft registered PK-LQP was operated as a scheduled passenger flight from Denpasar to Jakarta. Prior to the flight, the Angle of Attack (AoA) sensor had been replaced and tested.

    - The DFDR showed the stick shaker activated during the rotation and remained active throughout the flight. About 400 feet, the PIC noticed on the Primary Flight Display (PFD) that the IAS DISAGREE warning appeared.

    - The PIC cross checked both PFDs with the standby instrument and determined that the left PFD had the problem. The flight was handled by the SIC.

    - The PIC noticed that as soon the SIC stopped trim input, the aircraft was automatically trimming aircraft nose down (AND). After three automatic AND trim occurrences, the SIC commented that the control column was too heavy to hold back. The PIC moved the STAB TRIM switches to CUT OUT.

    - The pilot performed three Non-Normal Checklists (NNCs) consisting of Airspeed Unreliable, ALT DISAGREE, and Runaway Stabilizer. None of the NNCs performed contained the instruction “Plan to land at the nearest suitable airport”.

    - After parking in Jakarta, the PIC informed the engineer about the aircraft problem and entered IAS (Indicated Air Speed) and ALT (altitude) Disagree and FEEL DIFF PRESS (Feel Differential Pressure) light problem on the Aircraft Flight Maintenance Log (AFML).

    - The PIC also reported the flight condition through the electronic reporting system of the company A-SHOR.

    - The engineer performed flushing the left Pitot Air Data Module (ADM) and static ADM to rectify the IAS and ALT disagree followed by operation test on ground and found satisfied. The Feel Differential Pressure was rectified by performed cleaned electrical connector plug of elevator feel computer. The test on ground found the problem had been solved.

    - At 2320 UTC, (29 October 2018, 0620 LT) the aircraft departed from Jakarta using runway 25L and intended destination Pangkal Pinang. The DFDR recorded a difference between left and right Angle of Attack (AoA) of about 20° and continued until the end of recording. During rotation the left control column stick shaker activated and continued for most of the flight.

    - According to the weight and balance sheet, on board the aircraft were two pilots, five flight attendants and 181 passengers consisted of 178 adult, one child and two infants. The voyage report showed that the number of flight attendant on board was six flight attendants.

    - During the flight the LNI610 SIC asked the TE controller to confirm the altitude of the aircraft and later also asked the speed as shown on the TE controller radar display. The LNI610 SIC reported experienced „flight control problem‟.

    - After the flaps retracted, the FDR recorded automatic aircraft nose down (AND) trim active for 10 seconds followed by flight crew commanded aircraft nose up (ANU) trim. The flaps extended to 5 and the automatic AND trim stopped.

    - At 23:25:18 UTC, the flaps retracted to 0 and several seconds later, the automatic AND trim and flight crew commanded ANU trim recorded began again and continued for the remainder of the flight.

    - The LNI610 PIC advised the controller that the altitude of the aircraft could not be determined due to all aircraft instruments indicating different altitudes and requested to the controller to block altitude 3,000 feet above and below for traffic avoidance.

    - The flight crew and the flight attendants held valid licenses and medical certificates and certified to operate B737.

    - The Aircraft Flight Maintenance Log (AFML) recorded that since 26 October 2018 until the occurrence date, several problems occurred related to airspeed and altitude flag appeared on Captain (left) Primary Flight Display (PFD) three times, SPEED TRIM FAIL light illumination and MACH TRIM FAIL light illumination two times and IAS (Indicated Airspeed) and ALT (Altitude) Disagree shown on the flight Denpasar to Jakarta the day before the accident flight.

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