RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 3:54 am

speedbird52 wrote:
planecane wrote:
speedbird52 wrote:
Ah yes when a plane is trying to pitch itself into the ground and kill you the first thing you will think about is running the airspeed unreliable checklist. On another note, wasn't there a discussion about the 737 MAXs trim wheel being more difficult to use than the NG, and that's why they kept electric trim on? Or was that disproven.


The discussion was speciation that the NG trim wheel was more difficult to use than the classic. It was based on the wheel being smaller but nobody knew if the gearing was changed to compensate.

The wheel was used for over an hour by Lion Air 043 after cutting off electric trim.

Then the ET crew not using it doesn't make sense


Mentour pilot shows what it is like to try to deal with a simulated trim runaway. The Boeing EAD states that it may get harder to use the control column to maintain level flight. It becomes arm wrenchingly hard. That puts one pilot out of commission. The trim wheel is then the job of the other pilot. It is also arm wrenchingly hard to use. That puts the other pilot out of commission. It more or less gives the pilots a very limited opportunity to get it right.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 9:26 am

zoom321 wrote:
planecane wrote:
mysfit wrote:
It's lousy engineering and safety practice to EXPECT pilots to successfully counteract emergency which is caused by a single point failure resulting in a software fix for a mechanical issue going haywire during a heavy workload portion of flight.

Argue all you want about how pilots, with all hell breaking loose, should have responded. That really isn't even the point.

Crappy engineering of an issue handed pilots an accident waiting to happen. Single point failure. Non disclosure of a system which took control from them. The decision to make sure nothing more than an hour on an IPAD was needed. The reports by American pilots that the training manual was criminally negligent and lacking information on items unrelated to MCAS.

I don't hate Boeing but as an engineer, this was poorly executed and poorly designed. Engineers are responsible for limiting points for human error. Not to count on humans to overcome an intentionally introduced weak point. And then hide it.


Nobody can argue against the fact that MCAS 1.0 was a horrifically bad design. That said, the key reason for pilots to exist is to get the aircraft on the ground when things go wrong. It doesn't matter if the emergency is caused by a single failure or a chain of 65 events. The job of the pilots is to respond to the emergency.

The old "two wrongs don't make a right" saying cones into play here. The bad design of MCAS by Boeing doesn't excuse the crews from being capable of recovering.

Especially when they were able to do things that counteracted MCAS. Even if there was no checklist, if the trim goes nose down uncommanded but you can get back in trim with the thumb switch every time, why stop using the trim switch? I would like to think that pilots have some level of logic. If the Lion Air crew just kept trimming nose up they would have accidentally fixed the problem when they deployed flaps on approach.

Based on the preliminary report on the ET crash, it seems like they got tunnel vision about the cutoff switches which caused them to disable electric trim too soon. When they turned it back on, they didn't even try to counteract MCAS which they had done earlier.

I will reiterate, if Boeing had designed MCAS properly, neither crash would have happened. However, despite the bad design, the crews should have been able to recover. The fact that they didn't leads me to fear training deficiencies quite possibly on many aircraft and it has just been luck that the improperly trained crews have been lucky not to face emergency situations since the failure rates are so low.

Simulations have shown the ET coud not have recovered, so to say they should have been able to recover is based largely just on wishful thinking. Especially given the pilots were just following B procedures.
Training can/should be improved, but the most important steps to achieve this is B has to provide full disclosure on mcas, correct procedures to follow, working simulators & fix the manual trim so that pilots can be trained correctly, instead of continuing to provide half baked procedures whose main aim is to portray the steps as 'simple' & 'existing' over providing as much info as possible to ensure safety.

Simulations have NOT shown this. The one you are referring to I assume is the aviation week simulation. They started the simulation AFTER the electric trim was cut off.

The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

The aircraft was recoverable if they had used electric trim to balance out the control column forces before cutting off electric trim Lion Air 043 recovered from MCAS runaway and used the manual trim wheel for over an hour.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:29 am

planecane wrote:
The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

At some point, you could evolve you mindset from repeating the same over and over again and go the next step: contributing to understanding why ET302 was unable to save there lives.There did not committed a collective suicide to save Boeing from blames. There wanted to live. Something was so wrong that there failed to survive in that situation. Please respect the terrific facts from a human point of view. It's pointless to say that there could have survived just by there action, because there was a very large number of actions that others peoples could have done before to prevent that tragedy. There was only the last on that long chain of failure, under the focus of guys like you, but don't forget that there was a lot of peoples that could have saved the 737-8/9 MAX if there where doing the right action before.

From the ET302 preliminary report FDR trace, you can observe that the pilots already faced a master caution and a stick shaker on the left (and probably IAS disagree) at the rotation when about a single minute later there faced a MCAS AND and a GPWS warning while many of the previous issues was not cleared. In that untrained workload, there probably missed to notice the first trim wheels rotation period as there where busy at the beginning of the climb, to identify what the problem is, and to make strong aft column inputs. In that confusion there only partially corrected the first MCAS action. Then the MCAS killer generate an other AND command that the pilots fully corrected (en even a bit more) to the state before that second MCAS command. The correction there applied was probably based on the duration that there observed on the MCAS automatic wheels rotation. There wanted to cut that deadly MCAS without delay and used the cutoff switches to do so. Only then, there discovered that there can't use the trim wheels. For some minutes there was so confused that there did not found a way to solve there problem, but the situation was almost stable while some alerts, a stick shaker and strong aft column inputs remains. There wanted to solve the out of trim problem and since the wheels was not usable, there decided to reactivate the electric stab trim after an another master caution. There initially used the manual electric stab trim but a warning raised at the same time, that new confusion sopped there action, then MCAS killed all of them with a unrecoverable extreme out of trim.

The pilots was confused in a situation not well described in the documents there have access to, and that didn't match any training there followed. I still call for more 737 pilots out there to share a description in detail of a simulator runaway stabilizer training session at his airline.
 
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speedbored
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:29 am

planecane wrote:
zoom321 wrote:
planecane wrote:
The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:54 am

morrisond wrote:
xmp125a wrote:
planecane wrote:
2) MCAS does not introduce a new failure mode, it adds another source of runaway stabilizer.
3) MCAS appears to increase the likelihood of runaway stabilzer on a 737 by a few orders of magnitude.


MCAS-sourced runaway stabilizer presents much different symptoms. It is strictly periodical, and relentless. It is a failure mode no well trained pilot without MCAS knowledge would anticipate. Some would recognize it as runaway stabilizer, some would not. Because some didn't, 350 people were killed. And, for the cherry on top, MAX branded simulators actually did not include MCAS-induced variant of runaway stabilizer for the pilots to get familiar with the MCAS-variant of it.

The outcry of AA pilots after LionAir crash which has only now become public knowledge had a reason. Probably many of well trained pilots had their "oh (beep)" moment, realizing that what happened to LionAir **could** potentially hapen to them, experience and training notwithstanding.


So what is ETs excuse then - they knew all about it - Supposedly - I don't believe there airline actually told them so I hold the Pilots blameless if they were never told about it - however you think they would have done some independent research after Lionair


Pilots are not blameless here, but if I would be asked for numbers it would be 10% pilots, 90% Boeing. Independent research? Is that a joke? Pilots should get all the info in their hands, not relying on googling it... and even if, the fact that MCAS behaves differently than runaway stabilizer was not widely known to the public.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:06 pm

PixelFlight wrote:
planecane wrote:
The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

At some point, you could evolve you mindset from repeating the same over and over again and go the next step: contributing to understanding why ET302 was unable to save there lives.There did not committed a collective suicide to save Boeing from blames. There wanted to live. Something was so wrong that there failed to survive in that situation. Please respect the terrific facts from a human point of view. It's pointless to say that there could have survived just by there action, because there was a very large number of actions that others peoples could have done before to prevent that tragedy. There was only the last on that long chain of failure, under the focus of guys like you, but don't forget that there was a lot of peoples that could have saved the 737-8/9 MAX if there where doing the right action before.

From the ET302 preliminary report FDR trace, you can observe that the pilots already faced a master caution and a stick shaker on the left (and probably IAS disagree) at the rotation when about a single minute later there faced a MCAS AND and a GPWS warning while many of the previous issues was not cleared. In that untrained workload, there probably missed to notice the first trim wheels rotation period as there where busy at the beginning of the climb, to identify what the problem is, and to make strong aft column inputs. In that confusion there only partially corrected the first MCAS action. Then the MCAS killer generate an other AND command that the pilots fully corrected (en even a bit more) to the state before that second MCAS command. The correction there applied was probably based on the duration that there observed on the MCAS automatic wheels rotation. There wanted to cut that deadly MCAS without delay and used the cutoff switches to do so. Only then, there discovered that there can't use the trim wheels. For some minutes there was so confused that there did not found a way to solve there problem, but the situation was almost stable while some alerts, a stick shaker and strong aft column inputs remains. There wanted to solve the out of trim problem and since the wheels was not usable, there decided to reactivate the electric stab trim after an another master caution. There initially used the manual electric stab trim but a warning raised at the same time, that new confusion sopped there action, then MCAS killed all of them with a unrecoverable extreme out of trim.

The pilots was confused in a situation not well described in the documents there have access to, and that didn't match any training there followed. I still call for more 737 pilots out there to share a description in detail of a simulator runaway stabilizer training session at his airline.


You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:13 pm

planecane wrote:
You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.

Not to mention MCAS wouldn't have been a factor at all if they had remembered the memory item that says do not lower the flaps with the stick shaker active.
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planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:28 pm

speedbored wrote:
planecane wrote:
zoom321 wrote:

Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.


Step 4 is:

4 If the runaway continues:
STAB TRIM CUTOUT
switches (both) . . . . . . . . . . . . . . . . CUTOUT


At the time the ET pilots moved the switches to cutout, the runaway wasn't continuing becuase they were trimming nose up at the time and the stabilzer was moving as they were commanding it.

The proper thing for them to have done would have been to continue the trim inputs until neutral. Then, when MCAS kicked in again, immediately moved the switches to cutout because the runaway would have continued at that point.
Last edited by planecane on Mon May 20, 2019 12:36 pm, edited 1 time in total.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:35 pm

duplicate, please delete
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:48 pm

planecane wrote:
speedbored wrote:
planecane wrote:

Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.


Step 4 is:

4 If the runaway continues:
STAB TRIM CUTOUT
switches (both) . . . . . . . . . . . . . . . . CUTOUT


At the time the ET pilots moved the switches to cutout, the runaway wasn't continuing becuase they were trimming nose up at the time and the stabilzer was moving as they were commanding it.

The proper thing for them to have done would have been to continue the trim inputs until neutral. Then, when MCAS kicked in again, immediately moved the switches to cutout because the runaway would have continued at that point.
A little time on the simulator would have everyone sorted on that.
 
THS214
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 12:52 pm

[quote="planecane"]

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact./quote]

That was Air Florida 90 (Palm 90) and they were not calm nor professional.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 1:13 pm

RickNRoll wrote:
planecane wrote:
speedbored wrote:
Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.


Step 4 is:

4 If the runaway continues:
STAB TRIM CUTOUT
switches (both) . . . . . . . . . . . . . . . . CUTOUT


At the time the ET pilots moved the switches to cutout, the runaway wasn't continuing becuase they were trimming nose up at the time and the stabilzer was moving as they were commanding it.

The proper thing for them to have done would have been to continue the trim inputs until neutral. Then, when MCAS kicked in again, immediately moved the switches to cutout because the runaway would have continued at that point.
A little time on the simulator would have everyone sorted on that.


Seeing as this is part of a memory item NNC, I would agree. However, this has nothing to do with the MAX or MCAS. This is the same runaway stabilizer NNC that applies to all 737s going back to the -100. This is why my opinion is that the training issues that exist are not specific to the MAX. I don't believe that it is likely that either of these crews (and many others worldwide) would have recovered from a non-MCAS induced runaway stabilizer. Luckily, it seems that non-MCAS induced runaway stabilizer is extremely rare so my theory hasn't been put to the test.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 1:30 pm

planecane wrote:

You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.

In the first part you blame the ET302 pilot to not perform exactly a procedure, then in the second part you take as an example US1549 that deliberately avoided to follow exactly the procedure. Talking about US1549 the final report analyse in deep the procedures and explain how Airbus improved them because "crewmembers stated that it was not easy to jump from one procedure to another" (page 52). This show how much the manufacturer have to take care of procedures and to improve them, instead of simply assume that everything is like the previous model.

Did you listen to the ET302 CVR ? What prove did you have to claim that ET302 was not calm and professional in a never trained situation and deliberately badly redacted procedure ?
 
mjoelnir
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 1:33 pm

Revelation wrote:
planecane wrote:
You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.

Not to mention MCAS wouldn't have been a factor at all if they had remembered the memory item that says do not lower the flaps with the stick shaker active.


Is the stick shaker active is due to a faulty AoA and therefore active due to an error only, would memory items regarding stick shaker apply? The frame was clearly not stalling at that time.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 1:36 pm

PixelFlight wrote:
planecane wrote:

You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.

In the first part you blame the ET302 pilot to not perform exactly a procedure, then in the second part you take as an example US1549 that deliberately avoided to follow exactly the procedure. Talking about US1549 the final report analyse in deep the procedures and explain how Airbus improved them because "crewmembers stated that it was not easy to jump from one procedure to another" (page 52). This show how much the manufacturer have to take care of procedures and to improve them, instead of simply assume that everything is like the previous model.

Did you listen to the ET302 CVR ? What prove did you have to claim that ET302 was not calm and professional in a never trained situation and deliberately badly redacted procedure ?

There are couple of interesting comments regarding procedures in US1549 report. Actually things could be much worse if they followed procedures, smart deviation was the key. But quod licet Iovi, non licet bovi.
 
zoom321
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 2:08 pm

planecane wrote:
zoom321 wrote:
planecane wrote:

Nobody can argue against the fact that MCAS 1.0 was a horrifically bad design. That said, the key reason for pilots to exist is to get the aircraft on the ground when things go wrong. It doesn't matter if the emergency is caused by a single failure or a chain of 65 events. The job of the pilots is to respond to the emergency.

The old "two wrongs don't make a right" saying cones into play here. The bad design of MCAS by Boeing doesn't excuse the crews from being capable of recovering.

Especially when they were able to do things that counteracted MCAS. Even if there was no checklist, if the trim goes nose down uncommanded but you can get back in trim with the thumb switch every time, why stop using the trim switch? I would like to think that pilots have some level of logic. If the Lion Air crew just kept trimming nose up they would have accidentally fixed the problem when they deployed flaps on approach.

Based on the preliminary report on the ET crash, it seems like they got tunnel vision about the cutoff switches which caused them to disable electric trim too soon. When they turned it back on, they didn't even try to counteract MCAS which they had done earlier.

I will reiterate, if Boeing had designed MCAS properly, neither crash would have happened. However, despite the bad design, the crews should have been able to recover. The fact that they didn't leads me to fear training deficiencies quite possibly on many aircraft and it has just been luck that the improperly trained crews have been lucky not to face emergency situations since the failure rates are so low.

Simulations have shown the ET coud not have recovered, so to say they should have been able to recover is based largely just on wishful thinking. Especially given the pilots were just following B procedures.
Training can/should be improved, but the most important steps to achieve this is B has to provide full disclosure on mcas, correct procedures to follow, working simulators & fix the manual trim so that pilots can be trained correctly, instead of continuing to provide half baked procedures whose main aim is to portray the steps as 'simple' & 'existing' over providing as much info as possible to ensure safety.

Simulations have NOT shown this. The one you are referring to I assume is the aviation week simulation. They started the simulation AFTER the electric trim was cut off.

The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

The aircraft was recoverable if they had used electric trim to balance out the control column forces before cutting off electric trim Lion Air 043 recovered from MCAS runaway and used the manual trim wheel for over an hour.

There are reasons real pilots from Mentour Pilot to those who did the ET simulation simulated the way they did. Hint, it's not because they know less than you or has a hidden agenda.
It's because that's how most pilots would read the procedure, especially in an emergency & in light of how B broadcast to the world how simply electric trim cut off would save the day. No extra training or roller coaster mumbo jumbo needed.
B put in a half baked procedure with cursory mention of 'balance out the control column forces' when it is in fact a life and death critical step.
If there is indeed blame here, logical people would blame B for having all the time in the world yet failed to put in clear & correct English words, can they do anything right ?, instead of pilots who have seconds to react in a life/death situation with little/confusing info.
For those interested in the pilots' role, here are some nice consolidations of the facts.

https://www.zerohedge.com/news/2019-05- ... ilot-error
https://www.youtube.com/watch?v=ZtHBz2-YpWE
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 2:11 pm

zoom321 wrote:
planecane wrote:
zoom321 wrote:
Simulations have shown the ET coud not have recovered, so to say they should have been able to recover is based largely just on wishful thinking. Especially given the pilots were just following B procedures.
Training can/should be improved, but the most important steps to achieve this is B has to provide full disclosure on mcas, correct procedures to follow, working simulators & fix the manual trim so that pilots can be trained correctly, instead of continuing to provide half baked procedures whose main aim is to portray the steps as 'simple' & 'existing' over providing as much info as possible to ensure safety.

Simulations have NOT shown this. The one you are referring to I assume is the aviation week simulation. They started the simulation AFTER the electric trim was cut off.

The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.

The aircraft was recoverable if they had used electric trim to balance out the control column forces before cutting off electric trim Lion Air 043 recovered from MCAS runaway and used the manual trim wheel for over an hour.

There are reasons real pilots from Mentour Pilot to those who did the ET simulation simulated the way they did. Hint, it's not because they know less than you or has a hidden agenda.
It's because that's how most pilots would read the procedure, especially in an emergency & in light of how B broadcast to the world how simply electric trim cut off would save the day. No extra training or roller coaster mumbo jumbo needed.
B put in a half baked procedure with cursory mention of 'balance out the control column forces' when it is in fact a life and death critical step.

If there is indeed blame here, logical people would blame B for having all the time in the world yet failed to put in clear & correct English words, can they do anything right ?, instead of pilots who have seconds to react in a life/death situation with little/confusing info.
For those interested in the pilots' role, here are some nice consolidations of the facts.

https://www.zerohedge.com/news/2019-05- ... ilot-error
https://www.youtube.com/watch?v=ZtHBz2-YpWE

when it is in fact a life and death critical step requiring diagnostics of MCAS runaway (everything in trim system works perfectly, take your time to settle things down) vs true runaway (relay failed - you're wasting time and precious trim playing with that switch, hit those cutoffs ASAP)
 
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speedbored
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 2:35 pm

planecane wrote:
speedbored wrote:
planecane wrote:

Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.



The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 2:49 pm

speedbored wrote:
planecane wrote:
speedbored wrote:
Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.



The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.


First of all, the pilots follow the NNC, not the AD. Second, the part you are referring to is describing what trim is available depending on the position of the switches. It is not directing an action.
 
AirBoat
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 2:55 pm

agree with above.
I was taught to fly where trim is used to enable the plane to fly hands off, not to reduce forces.
The 737 has software protection to prevent overstress of the elevators, which shows itself has higher control forces. The parts of the flight envelope where this happens should be pointed out very clearly (high speed) or Vne should be pulled back to a much lower value.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 3:15 pm

planecane wrote:
zoom321 wrote:
Simulations have shown the ET coud not have recovered, so to say they should have been able to recover is based largely just on wishful thinking. Especially given the pilots were just following B procedures.
Training can/should be improved, but the most important steps to achieve this is B has to provide full disclosure on mcas, correct procedures to follow, working simulators & fix the manual trim so that pilots can be trained correctly, instead of continuing to provide half baked procedures whose main aim is to portray the steps as 'simple' & 'existing' over providing as much info as possible to ensure safety.

. . . . They started the simulation AFTER the electric trim was cut off.
The ET crew did not follow the runaway stabilizer NNC exactly because they cut off electric trim before they balanced the control column forces.
The aircraft was recoverable if they had used electric trim to balance out the control column forces before cutting off electric trim Lion Air 043 recovered from MCAS runaway and used the manual trim wheel for over an hour.


At this point, that is stil an assumption. We do not know why the uptrim stopped. The prelim report does not state that the uptrim stopped because of that. It does not stat ethat the uptrim was cut short/interrupted by the switches.

It may very well be because they flipped the switchers. But it may also be that they flipped the switches because/after the uptrim stopped for reasons not yet understood.
I find it (very) remarkable that ALL four manual electric uptrim actions (after MCAS became alive) stopped at the very same stabelizer angle. That could suggest that some other factor was going on, aside from crew intervention.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
AirwayBill
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 3:35 pm

As suspected before, a hypothetical quick re-entry into service of the MAX is looking grimmer with every day that passes, despite reassuring news about the "fix". Possibly a new hint:

Ryanair has confirmed it will not take delivery of its first B737 Max aircraft until this winter, while stressing that “we continue to have utmost confidence in these aircraft”.


https://www.businesstraveller.com/business-travel/2019/05/20/ryanair-delays-first-b737-max-delivery-until-winter/
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 3:35 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:

So how many MAX's do you think would actually get into a stall and crash if they didn't have MCAS? They would have to pull through this slightly light area of control force, ignore the stick shaker, the warning alarms and the frame buffeting for probably 10-20 seconds before entering an actual stall and then not be able to recover it - which should be achievable by any commercial pilot.

I have no idea. Do you?
What is the certification standard for such event? 1 E-10 or something like that?
How would you go about convincing FAA (and EASA, TCCA etc) that such event is so extremely rare, that it doesn not need to be taken into account in the design?
Again, I don't know. Do you?
But the FACT that 1) a FAR was devised for such condition, and 2) Boeing did not request a waiver on said FAR, but instead went through the trouble of designing and implementing MCAS, tells me it is not an acceptable situation against today's standards. Perhaps 25 years ago it was acceptable, today it is not.

I would say the odds of a crash of a MAX without MCAS due to a stall would be about Zero. A non-pilot could learn in about 5 minutes how to avoid the stall - it is the most basic and easily achieved maneuver - easier than keeping the plane straight and level..


Avoiding a stall in banking turn, in turbulence, close to MTOW, with aft CoG, in a high work load environment, may be a bit more complicated.
Add to that picture a lack of (natural) pitch stability margin (like the MAX), things might get out of your hands pretty quickly.

I tend to believe that he FAR's are there for a good reason. And fact is that the MAX does not meet (some of) them without MCAS. It is that simple.

If a non-pilot could learn that in five minutes, then surely a 250 hr ATP rated 737 pilot should have no problem with that, at all. However FAA and EASA have reasons to believe otherwise.
But hey, good luck convincing FAA (or better, EASA) that that specific FAR is rubbish and should not apply to 737 MAX.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 3:37 pm

Jamie514 wrote:
morrisond wrote:
MartijnNL wrote:
There is a serious flaw in the Boeing 737 MAX and that is the MCAS system.


I totally agree.

And the FAA certification system as well as the training system - all three are deficient.


The training system is just fine.

I agree, the training system is good enough (= worldwide safety records of all aircraft except the MAX are good enough).

The MAX on the other hand has the safety record of a plane from the sixties. It is grounded because it had serious and dangerous flaws. Nothing similar happened with any other aircraft ever. The crucial points are:
- Two MAX crashes shortly after EIS with one big common contributing factor are a strong indication, that the aircraft is at fault. Singular events decades after EIS not.
- The crash rate is astronomically high compared with other aircraft. There would be dozens of A320 and NG crashes per year, if they would crash as frequent.
- So even all the bad pilots of this world are not damaging the supreme safety record of the NG and the A320.

Maybe only US pilots should be qualified to fly the MAX?

OldAeroGuy wrote:
1) American Airlines operates about 12 times as many 737 NG's as Ethiopian (304 vs 26) but none of them has been involved in a loss of control crash. Likewise for Delta (203 737 NG's) and United (329 737 NG's), there have been no loss of control accidents.

Even in total absence of bad pilots, the MAX is grounded in the US too. So your remark must be off topic in this thread (which is called Boeing 737MAX Grounded Worldwide Q2 2019).
Many things are difficult, all things are possible!
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 4:39 pm

7BOEING7 wrote:
RickNRoll wrote:
planecane wrote:

The discussion was speciation that the NG trim wheel was more difficult to use than the classic. It was based on the wheel being smaller but nobody knew if the gearing was changed to compensate.

The wheel was used for over an hour by Lion Air 043 after cutting off electric trim.


They also had to add a damper to the NG, which added to the force required to operate it.


Which is not an issue during normal operations.


This whole discussion has been about non normal operations. Just when you need it you find it is very difficult to use if trim is not in balance and over time Boeing has made it more difficult to use the manual trim as a compromise to allow new systems to be installed. Which appears to be history of some critical 737 systems. No emergency window evacuation slides, for example.

Just as well this wasn't a real bomb.

https://www.express.co.uk/travel/articl ... air-flight
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 5:21 pm

PW100 wrote:
morrisond wrote:
PW100 wrote:
I have no idea. Do you?
What is the certification standard for such event? 1 E-10 or something like that?
How would you go about convincing FAA (and EASA, TCCA etc) that such event is so extremely rare, that it doesn not need to be taken into account in the design?
Again, I don't know. Do you?
But the FACT that 1) a FAR was devised for such condition, and 2) Boeing did not request a waiver on said FAR, but instead went through the trouble of designing and implementing MCAS, tells me it is not an acceptable situation against today's standards. Perhaps 25 years ago it was acceptable, today it is not.

I would say the odds of a crash of a MAX without MCAS due to a stall would be about Zero. A non-pilot could learn in about 5 minutes how to avoid the stall - it is the most basic and easily achieved maneuver - easier than keeping the plane straight and level..


Avoiding a stall in banking turn, in turbulence, close to MTOW, with aft CoG, in a high work load environment, may be a bit more complicated.
Add to that picture a lack of (natural) pitch stability margin (like the MAX), things might get out of your hands pretty quickly.

I tend to believe that he FAR's are there for a good reason. And fact is that the MAX does not meet (some of) them without MCAS. It is that simple.

If a non-pilot could learn that in five minutes, then surely a 250 hr ATP rated 737 pilot should have no problem with that, at all. However FAA and EASA have reasons to believe otherwise.
But hey, good luck convincing FAA (or better, EASA) that that specific FAR is rubbish and should not apply to 737 MAX.


The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.

Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.
 
OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:07 pm

rheinwaldner wrote:

OldAeroGuy wrote:
1) American Airlines operates about 12 times as many 737 NG's as Ethiopian (304 vs 26) but none of them has been involved in a loss of control crash. Likewise for Delta (203 737 NG's) and United (329 737 NG's), there have been no loss of control accidents.

Even in total absence of bad pilots, the MAX is grounded in the US too. So your remark must be off topic in this thread (which is called Boeing 737MAX Grounded Worldwide Q2 2019).


If you're going to quote me, please do so in the proper context.

The claim was made in this thread that ET , other than ET 302, had not had a loss of control crash in the last 15 years.

I pointed out that ET had had a 737 NG loss of control crash 10 years ago.

The original poster then claimed that one loss of control crash in 10 years was a good safety record.

My response, that you quoted, noted that several airlines, all operating many more 737 NG's than ET, had not had a 737 NG loss of control in the past 10 years.

ET's 737 NG loss of control accident rate is not exceptional.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:12 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:
I would say the odds of a crash of a MAX without MCAS due to a stall would be about Zero. A non-pilot could learn in about 5 minutes how to avoid the stall - it is the most basic and easily achieved maneuver - easier than keeping the plane straight and level..


Avoiding a stall in banking turn, in turbulence, close to MTOW, with aft CoG, in a high work load environment, may be a bit more complicated.
Add to that picture a lack of (natural) pitch stability margin (like the MAX), things might get out of your hands pretty quickly.

I tend to believe that he FAR's are there for a good reason. And fact is that the MAX does not meet (some of) them without MCAS. It is that simple.

If a non-pilot could learn that in five minutes, then surely a 250 hr ATP rated 737 pilot should have no problem with that, at all. However FAA and EASA have reasons to believe otherwise.
But hey, good luck convincing FAA (or better, EASA) that that specific FAR is rubbish and should not apply to 737 MAX.


The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.


Gentlemen, perhaps it is a little simpler. Perhaps either a FAR waiver/noncompliance or a dual sensor MCAS (competent design) would push MAX toward a new type approval that would contrary to the commercial imperative.

Ray
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:17 pm

XRAYretired wrote:
morrisond wrote:
PW100 wrote:

Avoiding a stall in banking turn, in turbulence, close to MTOW, with aft CoG, in a high work load environment, may be a bit more complicated.
Add to that picture a lack of (natural) pitch stability margin (like the MAX), things might get out of your hands pretty quickly.

I tend to believe that he FAR's are there for a good reason. And fact is that the MAX does not meet (some of) them without MCAS. It is that simple.

If a non-pilot could learn that in five minutes, then surely a 250 hr ATP rated 737 pilot should have no problem with that, at all. However FAA and EASA have reasons to believe otherwise.
But hey, good luck convincing FAA (or better, EASA) that that specific FAR is rubbish and should not apply to 737 MAX.


The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.


Gentlemen, perhaps it is a little simpler. Perhaps either a FAR waiver/noncompliance or a dual sensor MCAS (competent design) would push MAX toward a new type approval that would contrary to the commercial imperative.

Ray

One thing I don't understand: 737 already has artificially applied elevator feel force, and even has separate set of Pitot tubes for that.
Why on earth tweaking that part, or a stick pusher, was not sufficient for force emulation, why aerodynamic solution?
"Just a little lighter controls" is not really an answer for that, there should be much more behind MCAS approach.
 
IADFCO
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:24 pm

morrisond wrote:
[...]
Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.
[...]


You don't know that.

That is your speculation, unless you are a 737 MAX pilot who has flown a MAX with MCAS inactive, or have looked at flight test, or wind tunnel test, or at least computational Boeing data concerning that flight condition, and you have told us explicitly in your posts that you are none of the above.

It may very well be that the situation is exactly as you say, but yours is a personal opinion, not fact. On the other hand, it may be just as possible that in fact stall on the MAX is quite different than on the NG, and much harder to recover from, due for example to much worse flow separation on the wing induced by engine physical size and placement. At this stage, you don't know it for a fact and neither do I.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:33 pm

kalvado wrote:
XRAYretired wrote:
morrisond wrote:

The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.


Gentlemen, perhaps it is a little simpler. Perhaps either a FAR waiver/noncompliance or a dual sensor MCAS (competent design) would push MAX toward a new type approval that would contrary to the commercial imperative.

Ray

One thing I don't understand: 737 already has artificially applied elevator feel force, and even has separate set of Pitot tubes for that.
Why on earth tweaking that part, or a stick pusher, was not sufficient for force emulation, why aerodynamic solution?
"Just a little lighter controls" is not really an answer for that, there should be much more behind MCAS approach.


You may be right. Either way, dont think FAR waiver would ever have been on the cards.

Ray
 
GalaxyFlyer
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 6:49 pm

speedbored wrote:
planecane wrote:
speedbored wrote:
Please do show us exactly where in the NNC it tells pilots to "balance the control column forces".



2 Autopilot (if engaged) . . . . . . . . . . . . .Disengage

Do not re-engage the autopilot.

Control airplane pitch attitude manually with
control column and main electric trim as
needed.



The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.


You clearly don’t understand how pitch is controlled—apply stick forces to achieve the desired pitch and airspeed, then use the trim to neutralize the stick force. One never holds the control force and not trim.


Gf
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 7:20 pm

OldAeroGuy wrote:
rheinwaldner wrote:
Even in total absence of bad pilots, the MAX is grounded in the US too. So your remark must be off topic in this thread (which is called Boeing 737MAX Grounded Worldwide Q2 2019).


If you're going to quote me, please do so in the proper context.

The claim was made in this thread that ET, other than ET 302, had not had a loss of control crash in the last 15 years.

Then that claim was off topic too.
Many things are difficult, all things are possible!
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 8:16 pm

GalaxyFlyer wrote:
speedbored wrote:
planecane wrote:




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.


You clearly don’t understand how pitch is controlled—apply stick forces to achieve the desired pitch and airspeed, then use the trim to neutralize the stick force. One never holds the control force and not trim.


Gf

Thank you for posting this. It is frustrating trying to have a discussion and people posting authoritative sounding posts when they don't have an understanding of how an aircraft is actually flown.
 
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AirlineCritic
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 9:14 pm

rheinwaldner wrote:
Jamie514 wrote:
morrisond wrote:

I totally agree.

And the FAA certification system as well as the training system - all three are deficient.


The training system is just fine.

I agree, the training system is good enough (= worldwide safety records of all aircraft except the MAX are good enough).

The MAX on the other hand has the safety record of a plane from the sixties. It is grounded because it had serious and dangerous flaws. Nothing similar happened with any other aircraft ever. The crucial points are:
- Two MAX crashes shortly after EIS with one big common contributing factor are a strong indication, that the aircraft is at fault. Singular events decades after EIS not.
- The crash rate is astronomically high compared with other aircraft. There would be dozens of A320 and NG crashes per year, if they would crash as frequent.
- So even all the bad pilots of this world are not damaging the supreme safety record of the NG and the A320.


I also agree. By the numbers, we're doing fine. Except when a new aircraft model is designed with split-second reaction requirements for a multi-symptom issue.

This isn't to say improvements shouldn't be done on the training and crew side. But... first things first, lets fix the planes so that their failure rate is much reduced and behaviour under failure becomes less severe.

I predicted planes back in the air in the fall some time. I still believe that's a likely time table. This isn't a super hard problem to solve, but it needs a serious effort, and may need more than a software fix, e.g., working manual backup.
 
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speedbored
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 9:19 pm

GalaxyFlyer wrote:
speedbored wrote:
planecane wrote:




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.


You clearly don’t understand how pitch is controlled—apply stick forces to achieve the desired pitch and airspeed, then use the trim to neutralize the stick force.

Oh but I do understand. I qualified as a commercial pilot many years ago and have flown 737s (classics). I had to give it up on medical grounds after a car crash.

Unlike you, apparently, I also understand human factors, especially those involved in high stress situations such as these.
GalaxyFlyer wrote:
One never holds the control force and not trim.

Agreed. But how do you know that that is not what the pilots tried to do? There is no reason why it has to be immediate unless the control column forces are excessive.

Have you even entertained the possibility that they might just have decided to prioritise disabling MCAS over correcting the trim? After all, Boeing explicitly told them in the AD that they WOULD be able to correct adverse trim using the manual trim wheel. IMO, the fact that they later tried re-enabling electric trim suggests that this is actually what happened.

planecane wrote:
Thank you for posting this. It is frustrating trying to have a discussion and people posting authoritative sounding posts when they don't have an understanding of how an aircraft is actually flown.

Just because people disagree with your assumptions about what happened does not mean that they do not understand what they are talking about. Until the final report comes out, you are only guessing, like everyone else. Some of us, however, are doing so without bias.
 
Edax
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 9:25 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:
I would say the odds of a crash of a MAX without MCAS due to a stall would be about Zero. A non-pilot could learn in about 5 minutes how to avoid the stall - it is the most basic and easily achieved maneuver - easier than keeping the plane straight and level..


Avoiding a stall in banking turn, in turbulence, close to MTOW, with aft CoG, in a high work load environment, may be a bit more complicated.
Add to that picture a lack of (natural) pitch stability margin (like the MAX), things might get out of your hands pretty quickly.

I tend to believe that he FAR's are there for a good reason. And fact is that the MAX does not meet (some of) them without MCAS. It is that simple.

If a non-pilot could learn that in five minutes, then surely a 250 hr ATP rated 737 pilot should have no problem with that, at all. However FAA and EASA have reasons to believe otherwise.
But hey, good luck convincing FAA (or better, EASA) that that specific FAR is rubbish and should not apply to 737 MAX.


The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.

Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.

I am not a pilot, just a regular flier. I take your word that a stall in this situation is easy to prevent, ( obviously but I would much rather have the pilots explore the limits of the aircraft in a simulator than with me in the back:-))

There is something which is bothering me and lurking trough 175 or so pages of this thread has not not sorted it. It is apparently not an imminent emergency, but it is kind of a grey zone and A 737 in a normal commercial flight should should not be in this position. Or as boeing puts it a MCAS intervention should be a very rare event, right?

And yet there are a number of pilots who have claimed to have experienced just that. Some of these may well be due to the post crash hysteria, but some of reports predate the crashes and seem to suggest that these interventions are not that rare considering the limited fleet and operational period.

Surely there are better, safer, implementations of MCAS. But the impression that it is needed with some apparent regularity frightends me. Makes me wonder whether when you fly a Max like a NG you may bring it closer to the stall limit than you intend to. Stability may be good but is it really as good as the NG?
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 9:34 pm

Revelation wrote:
planecane wrote:
You could also evolve your mindset. I do not think it is unreasonable to expect that pilots can perform a NNC, especially one that is a memory item. It shouldn't matter that there are other alerts and confusion. They should be trained to handle non-normal situations (hence the name of the checklist) and should remain calm and do their job.

Listen to the calmness in Sully's voice on the ATC communications. That is the frame of mind that is required by a professional pilot. I've even heard a CVR recording from a crash in the 70s or early 80s where one pilot calmly said "we're going down" and the other calmly responded "I know it." Just before impact.

The ET crew got "frazzled" and threw the cutout switches. I understand all of the alarms and instrument disagreement but they identified the problem. Had they remained calm and professional, the aircraft was recoverable without much skill required.

How many times will an emergency only have one single problem and no other distractions? I wouldn't think many real emergencies.

Not to mention MCAS wouldn't have been a factor at all if they had remembered the memory item that says do not lower the flaps with the stick shaker active.


The EAD says MCAS "could" experience a stick shaker event but makes no mention at all of not lowering the flaps as a means of avoiding nose diving into the dirt. The only option it gives is the Trim Runaway.
 
OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:05 pm

rheinwaldner wrote:
OldAeroGuy wrote:
rheinwaldner wrote:
Even in total absence of bad pilots, the MAX is grounded in the US too. So your remark must be off topic in this thread (which is called Boeing 737MAX Grounded Worldwide Q2 2019).


If you're going to quote me, please do so in the proper context.

The claim was made in this thread that ET, other than ET 302, had not had a loss of control crash in the last 15 years.

Then that claim was off topic too.


The claim was being made to illustrate the efficacy of ET pilot training. As pilot training levels have been discussed extensively in this thread, it was relevant to the general topic.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Jamie514
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:21 pm

OldAeroGuy wrote:
rheinwaldner wrote:

OldAeroGuy wrote:
1) American Airlines operates about 12 times as many 737 NG's as Ethiopian (304 vs 26) but none of them has been involved in a loss of control crash. Likewise for Delta (203 737 NG's) and United (329 737 NG's), there have been no loss of control accidents.

Even in total absence of bad pilots, the MAX is grounded in the US too. So your remark must be off topic in this thread (which is called Boeing 737MAX Grounded Worldwide Q2 2019).


If you're going to quote me, please do so in the proper context.

The claim was made in this thread that ET , other than ET 302, had not had a loss of control crash in the last 15 years.

I pointed out that ET had had a 737 NG loss of control crash 10 years ago.

The original poster then claimed that one loss of control crash in 10 years was a good safety record.

My response, that you quoted, noted that several airlines, all operating many more 737 NG's than ET, had not had a 737 NG loss of control in the past 10 years.

ET's 737 NG loss of control accident rate is not exceptional.



Sorry, Nope! If you're going to refer to my original post, please don't further distort my responses to suit your agenda.

See post #1030 where I did not claim anything but rather asked how many loss of control crashes ET has had in the last 15 years.

How many other planes has ET lost in the last 15 years due to mishandling?


You did bring up ET409 as a response, and I did acknowledge it. However I took issue with your decision to suddenly narrow the analysis to only the 737 fleets when comparing airlines since it obviously allows to skew ET's crash rate far higher than the overall fleet.


OldAeroGuy wrote:
Just two comments:

1) American Airlines operates about 12 times as many 737 NG's as Ethiopian (304 vs 26) but none of them has been involved in a loss of control crash. Likewise for Delta (203 737 NG's) and United (329 737 NG's), there have been no loss of control accidents.

ET's 737 NG accident rate has not been exceptional.


Post #1074 for my reply, quoted here:

Fine then. When examining the airlines safety record it would be smart to not cherry pick an analysis to a specific type like just the NG.

ET also havent crashed any of their other types since 2010.

If you can find another clear case of pilot error on ET after the late 70's or early 80's, let us know. *to be fair to USA, lets not count landing errors like ovverruns cuz the likes of AA and WN suck at those.


So to summarize, I never suggested ET as an airline had an overall crash record other than their real one. You elected to conflate crash rate of one type, with a rate for the entire airline's fleet, which will obviously have a distorting effect on their safety record.

Since you seemed, and indeed still seem, very hung up on restricting your look at just that ten year window to support the argument that they are "not exceptional", I asked you to look farther.

Rather than do this, you chose to drop the conversation. I can only assume that you reason to do this is that because as far as Ethiopian is concerned, there do not appear to be ANY OTHER CRASHES IN THE LAST 30 ODD YEARS RELATED TO TRAINING. Since you happily brought up AA and DL in your post about safety records, I did go on to point out later that the american carriers you happily point to as vaunted examples of safe ops have experienced their share of dangerous excusions and hard landing write offs the last decade. Not to mention things like AA587 when ET was busily not mishandling their planes.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:23 pm

RickNRoll wrote:
The EAD says MCAS "could" experience a stick shaker event but makes no mention at all of not lowering the flaps as a means of avoiding nose diving into the dirt..

Right, but I'm talking about the stick shaker that happened right after take off, a minute or more before MCAS activated, whereas you (like 60 Minutes Australia) start the timeline once MCAS was activated. It was a memory item to not lower the flaps when the stick shaker is active, yet that's what the pilots did. Given that MCAS is inhibited if the flaps are down, we would not get the result we did get if the pilots remembered their memory items. This is a key item with regard to Boeing's "plausible deniability", which so far is still intact from the legal point of view.
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OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:27 pm

RickNRoll wrote:

The EAD says MCAS "could" experience a stick shaker event but makes no mention at all of not lowering the flaps as a means of avoiding nose diving into the dirt. The only option it gives is the Trim Runaway.


The point is: Why were the Flaps retracted with an active stick shaker, contrary to the "STALL RECOVERY" NNC ?

https://imgur.com/JyM0nKQ

No Flap retraction -> No MCAS and need to run the "STAB RUNAWAY" NNC.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:45 pm

kalvado wrote:
XRAYretired wrote:
morrisond wrote:

The controls getting light is not a lack of pitch stability margin. The MAX is sufficiently stable according to the FAR's as discussed previously.

Avoiding a stall in the situation like you described above is more difficult but not some insurmountable task like you are trying to make it. You still have all the warnings and it's not like you will go from flying to full stall in a split second - you will really have to screw up for a good 5-10 seconds and then the correction is quite simple - push the control column forward.

Yes - even you could learn that in about 5 minutes.

It's a good idea to have the FAR that requires increasing stick force as you get close to stall as it's an additional clue - but in practise it won't really make anything safer.Unless you are assuming that current state of pilot competence is so bad they can't even keep a plane out a stall in normal flight (Yes conditions as you described above is normal flight) with all systems working.


Gentlemen, perhaps it is a little simpler. Perhaps either a FAR waiver/noncompliance or a dual sensor MCAS (competent design) would push MAX toward a new type approval that would contrary to the commercial imperative.

Ray

One thing I don't understand: 737 already has artificially applied elevator feel force, and even has separate set of Pitot tubes for that.
Why on earth tweaking that part, or a stick pusher, was not sufficient for force emulation, why aerodynamic solution?
"Just a little lighter controls" is not really an answer for that, there should be much more behind MCAS approach.


Why go for the 500lb gorilla option of 2.5 degrees horizontal stabiliser to tweak the control column feel? It is a bizarre concept.If a tweak was all that was needed why was the proposed 0.6 degree max movement quadrupled to 2.5 degree? Not my definition of a tweak.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:49 pm

GalaxyFlyer wrote:
speedbored wrote:
planecane wrote:




The exact quote of balancing the forces is in the FCOM I think. However, the NNC says to use the main electric trim to control the pitch attitude in step 2.

No, it does not. If the pilots could adequately control "airplane pitch" with just the control column, there would be no need to even touch the electric trim, if following what the NNC actually says. The wording "as needed" is negligently vague.

Also, the note at the bottom of the AD says:
Note: Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before <using the cutouts>. Manual stabilizer trim can be used after <using the ciutouts>.


The use of "may" and "can" clearly makes all of this optional. If the pilots had what they perceived to be adequate control just using the control column, then there is no reason for them to use electric trim. And why would they if MCAS keeps adding nose-down? The urgency would be on stopping that happening. They would then be able to remove any adverse trim afterwards using the manual trim wheel - the AD clearly says that they will be able to do so ("can"), though this is also negligently incorrect in some circumstances, it seems.


You clearly don’t understand how pitch is controlled—apply stick forces to achieve the desired pitch and airspeed, then use the trim to neutralize the stick force. One never holds the control force and not trim.


Gf


Or in this case, use MCAS to simultaneously change control force so your arms are being pulled out of their sockets and trim down to planet earth for you when you are not in auto pilot.
 
OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 10:49 pm

Jamie514 wrote:
Since you happily brought up AA and DL in your post about safety records, I did go on to point out later that the american carriers you happily point to as vaunted examples of safe ops have experienced their share of dangerous excusions and hard landing write offs the last decade. Not to mention things like AA587 when ET was busily not mishandling their planes.


Please recall you were the party that brought up ET's accident history and focused on Loss of Control incidents.

How many fatalities in the past 10 years for American, Delta and United? Or Southwest that had a single fatality caused by an unconfined engine failure, not related to Loss of Control. Or Ryan Air, another airline with a large 737 NG fleet?

Remember, these airlines have have Hundreds of 737 NG's apiece while ET has dozens in their fleet.
Last edited by OldAeroGuy on Mon May 20, 2019 11:03 pm, edited 1 time in total.
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:00 pm

OldAeroGuy wrote:
RickNRoll wrote:

The EAD says MCAS "could" experience a stick shaker event but makes no mention at all of not lowering the flaps as a means of avoiding nose diving into the dirt. The only option it gives is the Trim Runaway.


The point is: Why were the Flaps retracted with an active stick shaker, contrary to the "STALL RECOVERY" NNC ?

https://imgur.com/JyM0nKQ

No Flap retraction -> No MCAS and need to run the "STAB RUNAWAY" NNC.

ET302 _DID_NOT_STALL_ !!!!! How hard is that to understand, really ? :banghead:

There no point to do a NCC that do not correspond to the situation. Only the left AoA + MCAS erratically believed that a stall occurred and there where completely wrong.
You can't blame the pilots to not make the same mistake as the MCAS !!!
The rationality on this thread is going as low as some 737-8/9 MAX...
Last edited by PixelFlight on Mon May 20, 2019 11:09 pm, edited 3 times in total.
 
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SheikhDjibouti
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:02 pm

OldAeroGuy wrote:
The point is: Why were the Flaps retracted with an active stick shaker, contrary to the "STALL RECOVERY" NNC ?

Because they looked out of the window and could see they were clearly not in a stall situation?
Morrisond assures us that the numerous clues on approach to stall are so blindingly obvious that they cannot be missed. He has stalled a Cessna dozens of times. :yes:
Apart from the stick shaker, what indications of an approaching stall did they have?

No Flap retraction -> No MCAS and need to run the "STAB RUNAWAY" NNC.

Yeah, I get that.
Hindsight is a such a beautiful thing.
Nothing to see here; move along please.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:06 pm

OldAeroGuy wrote:
RickNRoll wrote:

The EAD says MCAS "could" experience a stick shaker event but makes no mention at all of not lowering the flaps as a means of avoiding nose diving into the dirt. The only option it gives is the Trim Runaway.


The point is: Why were the Flaps retracted with an active stick shaker, contrary to the "STALL RECOVERY" NNC ?

https://imgur.com/JyM0nKQ

No Flap retraction -> No MCAS and need to run the "STAB RUNAWAY" NNC.


Why are we discussing this? It should be all in the EAD.The full story so that pilots are fully informed of all aspects of MCAS failure mode and how to deal with it at take off, one of the most critical parts of a flight when the pilots are already experiencing a significant workload.

The first Lion Air flight the pilot felt a stick shaker but only on one side. It could mean a stall was imminent but knew the plane was flying perfectly with pitch and power, it was climbing with no other indication that it could stall. There you instantly have a critical point in time where there is only a short window of time to act correctly with a mass of conflicting information. Now you have a situation where subjective rather than objective opinions come into play and it because is now a game of odds, some pick right and some pick wrong.

Boeing should have had an addition to the EAD to say that if this happens at take-off, where a failed AoA condition will make itself known, perform the "STALL RECOVERY" NNC rather than wait for the MCAS to go berserk and perform the "RUNAWAY TRIM" NNC. Reading the EAD makes it clear Boeing already knew all this.
 
OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:15 pm

PixelFlight wrote:
ET302 _DID_NOT_STALL_ !!!!! How hard is that to understand, really ? :banghead:

There no point to do a NCC that do not correspond to the situation.


I understand perfectly well that ET 302 did not stall.

But the sticker shaker was active through out the ET 302 flight.

With an active stick shaker, why were the Flaps retracted?

Please do not say to avoid the Flaps 5 placard. The ET crew had complete control of pitch and power at Flaps 5.

Speed was controllable below the Flaps 5 placard by referencing either Left or Right Airspeed indicators.

It was the perfect set up to conduct the "Airspeed Unreliable" NNC.
Last edited by OldAeroGuy on Mon May 20, 2019 11:42 pm, edited 1 time in total.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 20, 2019 11:28 pm

OldAeroGuy wrote:
PixelFlight wrote:
ET302 _DID_NOT_STALL_ !!!!! How hard is that to understand, really ? :banghead:

There no point to do a NCC that do not correspond to the situation.


I understand perfectly well that ET 302 did not stall.

But the sticker shaker was active through out the ET 302 flight.

With an active stick shaker, why were the Flaps retracted?

Please do not say to avoid the Flaps 5 placard. The ET crew had complete control pitch and power at Flaps 5.

Speed was controllable below the Flaps 5 placard by referencing either Left or Right Airspeed indicators.

It was the perfect set up to conduct the "Airspeed Unreliable" NNC.


The Boeing EAD didn't think so.

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