10 ms·

> The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operati

> The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working. This is very damning to Boeing. It's precisely the procedure they prescribed and intended to mitigate possible MCAS caused trim runaway. In light of the fact that they put this in place as a justification for moving the engines forward without reclassifying the plane, I don't see how they can get around fault here. What a tragedy. I can't imagine the emotion those pilots must have felt after attempting to do exactly what they were told to do to keep the aircraft in the air, only to have the nose lurch back downwards. Godspeed, gentlemen. It wasn't your fault.

smaili 8y ago
Just out of curiosity, will there actually be any punishments handed out beyond just a slap on the wrist? Or is Boeing far too large of a corp to take on?
- geofft 8y ago
  Incidentally, Boeing has received billions of dollars in illegal tax subsidies from the US (as in, anti-competitive with non-US manufacturers like Airbus): https://www.bbc.com/news/business-38131611 https://www.bbc.com/news/business-38131611 So it's hard to imagine fines or market penalties actually conveying any productive sense of punishment.
  - CompelTechnic 8y ago
    >This marks a victory for Airbus in a war without end. >Back in September the European aerospace giant, which employs 15,000 people in the UK, was on the receiving end when it was found that billions of euros in low interest loans amounted to illegal subsidies. >Boeing celebrated that moment as a comprehensive victory which would deal a mortal blow to Airbus and result in more US jobs. >The reality is that neither of these companies can exist without government subsidies. Both of these companies are strategic assets to the countries that have them. So no surprise here. I'm not even upset at it- it's realpolitik.
- mgazzer 8y ago
  Still too early to tell, this report is just the first step and inevitably will invoke conversation around who's to blame. Boeing's bottom line would like this is be crew or operating procedure.
- AnabeeKnox 8y ago
  This is an absurd comment. The rule of law works in the USA as much as it does in other developed countries. There is no such thing as "too large to take on". I note though that there is not yet any evidence of a crime having been committed.
  - mpweiher 8y ago
    > There is no such thing as "too large to take on" Let me get you up to date: "The deal — four years after the 2008 collapse of Lehman Brothers nearly brought down the financial system — was criticized at the time, raising concerns about whether some banks had grown too big to face criminal indictment." "Citing anonymous officials close to the case, the New York Times reports that federal prosecutors spent months debating whether to issue criminal indictments for money laundering. Authorities eventually ruled it out as such charges could ultimately cost HSBC its charter to operate in the US, seriously undermining the country’s fragile economic recovery." https://www.nytimes.com/2017/12/11/business/dealbook/hsbc-us-charges.html https://www.nytimes.com/2017/12/11/business/dealbook/hsbc-us...
    - proctor 8y ago
      and the recent snc-lavalin case in canada[0] [...Quebec Premier François Legault said that SNC-Lavalin was one of ten publicly-traded companies headquartered in Quebec that the province considers to be "strategic" and therefore in need of protection from a takeover that would force the company to leave the province....] https://en.wikipedia.org/wiki/SNC-Lavalin#SNC-Lavalin_affair_(2019) https://en.wikipedia.org/wiki/SNC-Lavalin#SNC-Lavalin_affair...
- Arnt 8y ago
  I've read a couple of these things (strongly recommended — aviation postmortems are a model for us all) and my impression is that "too large" or "slap" are foreign terms in their debugging culture. Their priority list is, AFAICT: 1. Find out what happened. 2. Find out why. 3. Find out how to make sure it doesn't happen again. 4. See point 3. 5. See point 3.
  - AnimalMuppet 8y ago
    If "why" turns out to be "runaway corporate greed", what do you do for steps 3, 4, and 5? Not that I think that's going to be the result of step 2. It was a contributing factor, probably, but it's not the whole story by any means.
    - Arnt 8y ago
      I don't think you would say that if you had read such a report. The ones I have read do not feature three-word explanations, but rather say things like "the chain of events that led to the accident could have been stopped at any of these single points: <seven items> and would also have been stopped if both a&b had been done, or if both c&d, or both c&e" and then discuss how each of the many might be changed. They don't say "five of the links in the event chain were at a profit-hungry corporation, whose CEO should be thrown in gaol, then they'll know to do that differently in the future". "Runaway corporate greed" is fine reason for a quick and angry post on a social network, but aviation postmortems are a different kind of beast, heavy on analysis and prevention, light on anger.
      - chopin 8y ago
        As the Seattle Times reported, the MCAS system was mis-characterized by Boeing. Rules don't help if you don't go by them. This postmortem must include "runaway corporate greed" absolutely. Not sure what can be done about it as the FAA is not trustworthy anymore.
  - nutjob2 8y ago
    What happened is that they hacked on an inappropriate engine onto an old airframe, then they hacked a hidden automation to fix the prior hack. The engineering fix is obvious, but management is the problem.
- drstewart 8y ago
  What charges do you recommend? Links to the US code here: https://www.law.cornell.edu/uscode/text https://www.law.cornell.edu/uscode/text
- jhayward 8y ago
  We are at the 'accident investigation' stage. Accident investigators do not hand out punishments. That comes later, during civil or criminal procedures in the various courts of jurisdiction, and by the regulators. It is certainly within the realm of possibility that there will be severe consequences, up to and including criminal charges.
- zaroth 8y ago
  My predictions? - Boeing will lose 10s of billions of dollars because of this in damages, lost contracts, and redesign costs. - Their CEO will resign. - The FAA will revamp many procedures to vastly increase certification costs and not allow these types of same-class-rating bullshit. - The FAA or similar EU agencies may slap some fine against Boeing - The families will sue and win a large settlement. - One or more engineers may commit suicide. (which would be itself tragic) - Middle management will pay zero or nearly zero price. - No one will be internally fired by Boeing as the problem is systemic. - No criminal charges. Many of these things will only happen with a sustains public relations compaign against Boeing, congressional hearings, persistent news articles, documentaries highlighting the harrowing crash, etc. EDIT: I’d say there’s a small chance even that a system called MCAS never flies again, even if that means the entire MAX concept has to be shelved. If the MAX can fly without MCAS but just under a new type rating, that could be the way they go. Boeing simply has not been successful introducing computer-moderated flight controls and envelopes the way that Airbus has over the last decade (and those lessons were hard learned too).
fgonzag 8y ago
This means that Boeing is now 100% liable for the crash, as there was nothing the airline could've done in this scenario. It also means that the aircraft will have to be re-designed and re-classified before it ever flies again (it's now a very clear design error, not a training or communication error)
- weaksauce 8y ago
  Thechnically they could have used the thumb switch and regained level flight to override the mcas system temporarily and then shut off the electrical system to the stab and trim manually thereafter. However, they didn’t know about the mcas system and the troubleshooting steps that Boeing has for that mode of failure were insufficient for this precise scenario.
  - fgonzag 8y ago
    At 05:43:20, approximately five seconds after the last manual electric trim input, an AND automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds. The aircraft began pitching nose down. Additional simultaneous aft column force was applied, but the nose down pitch continues, eventually reaching 40° nose down. The stabilizer position varied between 1.1 and 0.8 units for the remainder of the recording. It seems they tried it but MCAS kicked 5 seconds after they turned on the electrical trim. They didn't have enough time to correct the stabilizer. I don't know how fast returning a stabilizer to neutral position can be done, but they probably thought they had more than 5 seconds. They were probably going to turn off electronic trim control afterwards.
    - cjbprime 8y ago
      I've read that it takes the trim motor 30 seconds to move the jackscrew completely along its path. It was found all the way at one end in the wreck. So naively, it takes up to 15 seconds of continuous motor operation to recover level flight.
    - JRKrause 8y ago
davepage 8y ago
It does not appear to be "precisely" the procedure, in that sufficient nose up trim was not selected by the yoke manual trim switch prior to pulling the trim cutouts. And then they did not work the mechanical trim wheel hard enough to reset the residual nose down trim. And, the crew left the power setting at climb throughout almost the entire sequence, so they oversped the airframe. And, when they (against procedure) (apparently) turned the electric trim system back on, they did not use the yoke manual trim switch to fix the nose down trim problem -- which is a big mystery. The MCAS design inhibits its FCC trim down output when manual trim is utilized. So, if they had just continuously pushed the nose up manual trim switch on the yoke until they got the trim to neutral, then pulled the cutout (either the first time or second time), the accident could have been avoided. History shows this is not a good human factors design on the part of Boeing, but the crew does not look good, either, IMO.
- cjbprime 8y ago
  > sufficient nose up trim was not selected by the yoke manual trim switch prior to pulling the trim cutouts The EAD/service bulletin doesn't talk about sufficient nose up trim or caution against performing the cutout with even a slight mistrim. > And then they did not work the mechanical trim wheel hard enough to reset the residual nose down trim. It's possible that aerodynamic load (of the stabilizer opposing the elevator) made it physically impossible to manually trim given any mistrim at the time the cutout happened, given the airspeed they had. And, the captain is pulling back on the yoke as hard as he can, so he's unavailable to let go of it and grab a trim wheel instead without immediately losing altitude. > And, when they (against procedure) (apparently) turned the electric trim system back on It seems sensible to assume -- and the report states -- that they did this because they found that manual trim was impossible in these circumstances.
  - kayfox 8y ago
    > It's possible that aerodynamic load (of the stabilizer opposing the elevator) made it physically impossible to manually trim given any mistrim at the time the cutout happened, given the airspeed they had. Its been noted in previous discussions that while it would be difficult, the load can be overcome if both pilots were to operate the manual trim wheel at the same time. Not that its a good situation to be in.
cjbprime 8y ago
> The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working. Are they talking about manual electric trim, or physically moving the trim wheel with its handle? I would expect manual electric trim to stop working after you STAB TRIM CUTOUT, since that kills the trim motor. Did the pilots try physically moving the trim wheel?
fuckyah 8y ago
"After the autopilot disengaged, the DFDR recorded an automatic aircraft nose down (AND) trim command four times without pilot’s input." This seems to be key imo, why is there no master switch to completely turn off any computer assisted steering?
crimsonalucard 8y ago
Even if this wasn't successfully done they would still be at fault. A plane is suppose to operate without have to have to do this, the procedures are a safety protocol. For the MCAS and safety protocol to fail is a double whammy.
dboreham 8y ago
Wondering why Boeing stock went up today...
- ars 8y ago
  Because this report does not indicate a new problem, but rather the same one as before, which has already been accounted for in the stock price. It's a truism of stocks that they move opposite of what you would expect when the final result comes in, and that's because they have already moved when news of whatever it is is released. Eg: Company announces we will get 1 billion cash for free, stock goes up. when they actually get the cash, stock will go down. Replace that scenario with whatever is making news about the company (mergers, new sales, personal changes, etc, etc).
tmd83 8y ago
I'm not versed in the terminologies. What I understood was told previously is that In similar condition (nose down) in other plane just pulling the stick would work but with MCAS you have shut it down using some switch and just the stick won't work. And now the report is saying even that switch doesn't work? That one MCAS goes bonkers there's essentially no recourse?
- cjbprime 8y ago
  The switch works to disable MCAS, but at the cost of also disabling the trim motor, which is what you need to use to recover from what MCAS was doing before you disabled it. It is as ludicrous as it sounds.
calecon323 8y ago
Except they didn't "follow procedure." MCAS trimmed down repeatedly on one instance for 9(!) seconds and yet the pilots waited 3 seconds longer to counteract that with an electric trim up command on the yoke. The procedure is not 1. Let MCAS do its thing 2. Pull back on the stick 3. Hit the stab trim cut off when you have had enough. Attempting to counteract the the trim down command with manual trimming commands should occur continuously "as needed." If you don't attempt to override the trim runaway with manual trim up commands on your control yoke you aren't following the checklist. On the 737 you can see the trim wheels move and if unintended follow the checklist. The pilots didn't do that at all. Sustained manual trim only occurred after MCAS kicked in again at 5:40:27 and the pilots still waited before invoking the trim up command. The pilots never invoked sufficient trim up to counteract the automatic trim down command. Again, there is a reason the trim controls are on the control yoke in the first place. Of the three major MCAS trim down commands the pilots only stopped the second one with manual commands after it had already pushed the nose dangerously low. If the pilots had simply invoked manual trim promptly and counteracted the erroneous trim manual trim would have been successful after invoking a STAB CUT out. If you think the pilots are following procedure why at 05:41:46 did: "the Captain ask[ed] the First-Officer if the trim is functional." ? That doesn't make sense, of course the trim doesn't work, the STAB TRIM cut out switches were engaged! But the response by the first officer was that "The First-Officer [has] replied that the trim was not working and asked if he could try it manually." which again doesn't make sense. But it gets worse because this happened a FULL MINUTE after the stab cut out switch was engaged, which means that neither pilot tried to manually trim the aircraft during that time at all! But it gets better: "At 05:40:27, the Captain advised the First-Officer to trim up with him. " Which again doesn't make sense because it wouldn't make any difference if the both pilots were trimming up or not, the stabilizer doesn't move any faster. My conclusion is that the pilots didn't know the checklist but its hard to tell because the CDR isn't presented completely.

smaili 8y ago

Just out of curiosity, will there actually be any punishments handed out beyond just a slap on the wrist? Or is Boeing far too large of a corp to take on?

geofft 8y ago
Incidentally, Boeing has received billions of dollars in illegal tax subsidies from the US (as in, anti-competitive with non-US manufacturers like Airbus): https://www.bbc.com/news/business-38131611 https://www.bbc.com/news/business-38131611 So it's hard to imagine fines or market penalties actually conveying any productive sense of punishment.
- CompelTechnic 8y ago
  >This marks a victory for Airbus in a war without end. >Back in September the European aerospace giant, which employs 15,000 people in the UK, was on the receiving end when it was found that billions of euros in low interest loans amounted to illegal subsidies. >Boeing celebrated that moment as a comprehensive victory which would deal a mortal blow to Airbus and result in more US jobs. >The reality is that neither of these companies can exist without government subsidies. Both of these companies are strategic assets to the countries that have them. So no surprise here. I'm not even upset at it- it's realpolitik.
mgazzer 8y ago
Still too early to tell, this report is just the first step and inevitably will invoke conversation around who's to blame. Boeing's bottom line would like this is be crew or operating procedure.
AnabeeKnox 8y ago
This is an absurd comment. The rule of law works in the USA as much as it does in other developed countries. There is no such thing as "too large to take on". I note though that there is not yet any evidence of a crime having been committed.
- mpweiher 8y ago
  > There is no such thing as "too large to take on" Let me get you up to date: "The deal — four years after the 2008 collapse of Lehman Brothers nearly brought down the financial system — was criticized at the time, raising concerns about whether some banks had grown too big to face criminal indictment." "Citing anonymous officials close to the case, the New York Times reports that federal prosecutors spent months debating whether to issue criminal indictments for money laundering. Authorities eventually ruled it out as such charges could ultimately cost HSBC its charter to operate in the US, seriously undermining the country’s fragile economic recovery." https://www.nytimes.com/2017/12/11/business/dealbook/hsbc-us-charges.html https://www.nytimes.com/2017/12/11/business/dealbook/hsbc-us...
  - proctor 8y ago
    and the recent snc-lavalin case in canada[0] [...Quebec Premier François Legault said that SNC-Lavalin was one of ten publicly-traded companies headquartered in Quebec that the province considers to be "strategic" and therefore in need of protection from a takeover that would force the company to leave the province....] https://en.wikipedia.org/wiki/SNC-Lavalin#SNC-Lavalin_affair_(2019) https://en.wikipedia.org/wiki/SNC-Lavalin#SNC-Lavalin_affair...
Arnt 8y ago
I've read a couple of these things (strongly recommended — aviation postmortems are a model for us all) and my impression is that "too large" or "slap" are foreign terms in their debugging culture. Their priority list is, AFAICT: 1. Find out what happened. 2. Find out why. 3. Find out how to make sure it doesn't happen again. 4. See point 3. 5. See point 3.
- AnimalMuppet 8y ago
  If "why" turns out to be "runaway corporate greed", what do you do for steps 3, 4, and 5? Not that I think that's going to be the result of step 2. It was a contributing factor, probably, but it's not the whole story by any means.
  - Arnt 8y ago
    I don't think you would say that if you had read such a report. The ones I have read do not feature three-word explanations, but rather say things like "the chain of events that led to the accident could have been stopped at any of these single points: <seven items> and would also have been stopped if both a&b had been done, or if both c&d, or both c&e" and then discuss how each of the many might be changed. They don't say "five of the links in the event chain were at a profit-hungry corporation, whose CEO should be thrown in gaol, then they'll know to do that differently in the future". "Runaway corporate greed" is fine reason for a quick and angry post on a social network, but aviation postmortems are a different kind of beast, heavy on analysis and prevention, light on anger.
    - chopin 8y ago
      As the Seattle Times reported, the MCAS system was mis-characterized by Boeing. Rules don't help if you don't go by them. This postmortem must include "runaway corporate greed" absolutely. Not sure what can be done about it as the FAA is not trustworthy anymore.
- nutjob2 8y ago
  What happened is that they hacked on an inappropriate engine onto an old airframe, then they hacked a hidden automation to fix the prior hack. The engineering fix is obvious, but management is the problem.
drstewart 8y ago
What charges do you recommend? Links to the US code here: https://www.law.cornell.edu/uscode/text https://www.law.cornell.edu/uscode/text
jhayward 8y ago
We are at the 'accident investigation' stage. Accident investigators do not hand out punishments. That comes later, during civil or criminal procedures in the various courts of jurisdiction, and by the regulators. It is certainly within the realm of possibility that there will be severe consequences, up to and including criminal charges.
zaroth 8y ago
My predictions? - Boeing will lose 10s of billions of dollars because of this in damages, lost contracts, and redesign costs. - Their CEO will resign. - The FAA will revamp many procedures to vastly increase certification costs and not allow these types of same-class-rating bullshit. - The FAA or similar EU agencies may slap some fine against Boeing - The families will sue and win a large settlement. - One or more engineers may commit suicide. (which would be itself tragic) - Middle management will pay zero or nearly zero price. - No one will be internally fired by Boeing as the problem is systemic. - No criminal charges. Many of these things will only happen with a sustains public relations compaign against Boeing, congressional hearings, persistent news articles, documentaries highlighting the harrowing crash, etc. EDIT: I’d say there’s a small chance even that a system called MCAS never flies again, even if that means the entire MAX concept has to be shelved. If the MAX can fly without MCAS but just under a new type rating, that could be the way they go. Boeing simply has not been successful introducing computer-moderated flight controls and envelopes the way that Airbus has over the last decade (and those lessons were hard learned too).

fgonzag 8y ago

This means that Boeing is now 100% liable for the crash, as there was nothing the airline could've done in this scenario. It also means that the aircraft will have to be re-designed and re-classified before it ever flies again (it's now a very clear design error, not a training or communication error)

weaksauce 8y ago
Thechnically they could have used the thumb switch and regained level flight to override the mcas system temporarily and then shut off the electrical system to the stab and trim manually thereafter. However, they didn’t know about the mcas system and the troubleshooting steps that Boeing has for that mode of failure were insufficient for this precise scenario.
- fgonzag 8y ago
  At 05:43:20, approximately five seconds after the last manual electric trim input, an AND automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds. The aircraft began pitching nose down. Additional simultaneous aft column force was applied, but the nose down pitch continues, eventually reaching 40° nose down. The stabilizer position varied between 1.1 and 0.8 units for the remainder of the recording. It seems they tried it but MCAS kicked 5 seconds after they turned on the electrical trim. They didn't have enough time to correct the stabilizer. I don't know how fast returning a stabilizer to neutral position can be done, but they probably thought they had more than 5 seconds. They were probably going to turn off electronic trim control afterwards.
  - cjbprime 8y ago
    I've read that it takes the trim motor 30 seconds to move the jackscrew completely along its path. It was found all the way at one end in the wreck. So naively, it takes up to 15 seconds of continuous motor operation to recover level flight.
  - JRKrause 8y ago

davepage 8y ago

It does not appear to be "precisely" the procedure, in that sufficient nose up trim was not selected by the yoke manual trim switch prior to pulling the trim cutouts. And then they did not work the mechanical trim wheel hard enough to reset the residual nose down trim. And, the crew left the power setting at climb throughout almost the entire sequence, so they oversped the airframe. And, when they (against procedure) (apparently) turned the electric trim system back on, they did not use the yoke manual trim switch to fix the nose down trim problem -- which is a big mystery. The MCAS design inhibits its FCC trim down output when manual trim is utilized. So, if they had just continuously pushed the nose up manual trim switch on the yoke until they got the trim to neutral, then pulled the cutout (either the first time or second time), the accident could have been avoided. History shows this is not a good human factors design on the part of Boeing, but the crew does not look good, either, IMO.

cjbprime 8y ago
> sufficient nose up trim was not selected by the yoke manual trim switch prior to pulling the trim cutouts The EAD/service bulletin doesn't talk about sufficient nose up trim or caution against performing the cutout with even a slight mistrim. > And then they did not work the mechanical trim wheel hard enough to reset the residual nose down trim. It's possible that aerodynamic load (of the stabilizer opposing the elevator) made it physically impossible to manually trim given any mistrim at the time the cutout happened, given the airspeed they had. And, the captain is pulling back on the yoke as hard as he can, so he's unavailable to let go of it and grab a trim wheel instead without immediately losing altitude. > And, when they (against procedure) (apparently) turned the electric trim system back on It seems sensible to assume -- and the report states -- that they did this because they found that manual trim was impossible in these circumstances.
- kayfox 8y ago
  > It's possible that aerodynamic load (of the stabilizer opposing the elevator) made it physically impossible to manually trim given any mistrim at the time the cutout happened, given the airspeed they had. Its been noted in previous discussions that while it would be difficult, the load can be overcome if both pilots were to operate the manual trim wheel at the same time. Not that its a good situation to be in.

cjbprime 8y ago

> The crew performed runaway stabilizer checklist and put the stab trim cutout switch to cutout position and confirmed that the manual trim operation was not working. Are they talking about manual electric trim, or physically moving the trim wheel with its handle? I would expect manual electric trim to stop working after you STAB TRIM CUTOUT, since that kills the trim motor. Did the pilots try physically moving the trim wheel?

fuckyah 8y ago

"After the autopilot disengaged, the DFDR recorded an automatic aircraft nose down (AND) trim command four times without pilot’s input." This seems to be key imo, why is there no master switch to completely turn off any computer assisted steering?

crimsonalucard 8y ago

Even if this wasn't successfully done they would still be at fault. A plane is suppose to operate without have to have to do this, the procedures are a safety protocol. For the MCAS and safety protocol to fail is a double whammy.

dboreham 8y ago

Wondering why Boeing stock went up today...

ars 8y ago
Because this report does not indicate a new problem, but rather the same one as before, which has already been accounted for in the stock price. It's a truism of stocks that they move opposite of what you would expect when the final result comes in, and that's because they have already moved when news of whatever it is is released. Eg: Company announces we will get 1 billion cash for free, stock goes up. when they actually get the cash, stock will go down. Replace that scenario with whatever is making news about the company (mergers, new sales, personal changes, etc, etc).

tmd83 8y ago

I'm not versed in the terminologies. What I understood was told previously is that In similar condition (nose down) in other plane just pulling the stick would work but with MCAS you have shut it down using some switch and just the stick won't work. And now the report is saying even that switch doesn't work? That one MCAS goes bonkers there's essentially no recourse?

cjbprime 8y ago
The switch works to disable MCAS, but at the cost of also disabling the trim motor, which is what you need to use to recover from what MCAS was doing before you disabled it. It is as ludicrous as it sounds.

calecon323 8y ago

Except they didn't "follow procedure." MCAS trimmed down repeatedly on one instance for 9(!) seconds and yet the pilots waited 3 seconds longer to counteract that with an electric trim up command on the yoke. The procedure is not 1. Let MCAS do its thing 2. Pull back on the stick 3. Hit the stab trim cut off when you have had enough. Attempting to counteract the the trim down command with manual trimming commands should occur continuously "as needed." If you don't attempt to override the trim runaway with manual trim up commands on your control yoke you aren't following the checklist. On the 737 you can see the trim wheels move and if unintended follow the checklist. The pilots didn't do that at all. Sustained manual trim only occurred after MCAS kicked in again at 5:40:27 and the pilots still waited before invoking the trim up command. The pilots never invoked sufficient trim up to counteract the automatic trim down command. Again, there is a reason the trim controls are on the control yoke in the first place. Of the three major MCAS trim down commands the pilots only stopped the second one with manual commands after it had already pushed the nose dangerously low. If the pilots had simply invoked manual trim promptly and counteracted the erroneous trim manual trim would have been successful after invoking a STAB CUT out. If you think the pilots are following procedure why at 05:41:46 did: "the Captain ask[ed] the First-Officer if the trim is functional." ? That doesn't make sense, of course the trim doesn't work, the STAB TRIM cut out switches were engaged! But the response by the first officer was that "The First-Officer [has] replied that the trim was not working and asked if he could try it manually." which again doesn't make sense. But it gets worse because this happened a FULL MINUTE after the stab cut out switch was engaged, which means that neither pilot tried to manually trim the aircraft during that time at all! But it gets better: "At 05:40:27, the Captain advised the First-Officer to trim up with him. " Which again doesn't make sense because it wouldn't make any difference if the both pilots were trimming up or not, the stabilizer doesn't move any faster. My conclusion is that the pilots didn't know the checklist but its hard to tell because the CDR isn't presented completely.