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morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:48 pm

767333ER wrote:
morrisond wrote:
flipdewaf wrote:
But that’s the point, the Likelihood of stalling increases with the nonlinear (in the form reducing force per g) stick forces vs linear or positive increase per g. It’s like saying you don’t need engine fire suppression, just make sure the engines don’t catch fire.

If the nonlinearity is slight it may be a trivial increase in risk. But the regs are there for good reason.

Fred



Sent from my iPhone using Tapatalk



If the non-linearity is slight yes it is a slight increase in risk. But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier. You also have multiple other types of warnings triggering as well (stick shaker, audio alarms, frame buffeting) hopefully the Pilots would pay attention to one of them.

If not do they really don't belong in a ...........? I'll let you fill in the missing word.

MCAS is not the equivalent of a stick pusher that will prevent a stall.

morrisond wrote:
PixelFlight wrote:
https://www.faa.gov/uas/commercial_operators/part_107_waivers/waiver_safety_explanation_guidelines/
Waiver Safety Explanation Guidelines for Part 107 Waiver Applications

Maybe a scenario, but not going to make a safer aircraft even safer...


No it wouldn't be quite as safe as an NG but if an NG crashes in 1 in 100 million flights a Max may crash in 1 in 99,999,999 flights without MCAS due to a stall.

If that 1 in 10,000 pilot or co-pilot gets into a Scenario where they are in a stall situation and ignore all the other warnings and they don't know enough to push the Control column forward and the Pilot/Co-pilot doesn't catch it either following along with the movement in the control column (impossible to do on an FBW aircraft that has controls that are not back driven) then yes it would be less safe than an NG.

I'm exaggerating my point above - but you are most likely talking about a very minor decrease in safety.

You cannot say such a thing if you do not know how a 737 MAX behaves approaching a stall without MCAS and until Boeing shows us what happens (that’s starting to get like Trump’s tax returns?) we can’t say it’s for sure a small increase in risk. The only sort of evidence we have is the apparent authority MCAS has AND the fact that they increased the authority it has during the development period. Take all this into account and we can’t say anything is likely or not likely, but we can make an inference and to me it looks like there is something sinister about the stall characteristics of the MAX. I don’t know for sure, nor do you, but to me these things make it look worse than it is “said” to be. Would they increase that authority if it was just a small risk of stick force lightening?

Now for the love of all things holy stop referring to pilot and co-pilot. A captain and a first officer are both pilots. Co-pilot is an inaccurate term.

Back driven controls Have zero relevance in this discussion. Arguing off point again.


Yes you are right - we don't know if the MAX has some unknown handling quirk. I just forgot to put that qualifier on this one post - but I have been doing that repeatedly.

I think I said yesterday that if it does have handling quirks that are impossible to offset without augmentation - it's time to put a bullet in it.

OK - on the First Officer/Co-Pilot thing - I get your point and that is a better way to describe the roles.

On the back driven vs non-back driven FBW systems I was just preempting one of the normal refrains we hear on this thread - the MAX should be redesigned with a full FBW system or not be RTS at all. Sure as long as it's back driven.

Non-back driven systems have been one of the primary causes of more fatalities than MCAS.
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:51 pm

morrisond wrote:
But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier.

For the hundredth time, MCAS is not a warning system. It exists so the muscle memory of pilots is not fooled by the easing control force. MCAS is all about behavior and nothing about informing the pilots.
Many things are difficult, all things are possible!
 
DenverTed
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:51 pm

XRAYretired wrote:
DenverTed wrote:
So now that Transport Canada has floated the idea of simply changing the FAA rules, the rules are just a subjective attempt to quantify safety, so I don't disagree with that, but. Which is statistically safer? Removing MCAS 2.0 and just dealing with the pitch behavior before stall, or leaving MCAS 2.0 on there? Seems like it is one very low probability event versus another. Flip a coin and choose either.

Misrepresentation. Mr Markos strawman is to demonstrate compliance with the Longitudinal Stability requirements and to modify the FCC software to comply with the Stall Characteristics requirement - not to change the requirements.

The regulations are not a subjective attempt to quantify safety. The have been developed to improve safety (on the graves of many) and that is what they do.

Ray

Subjective as in a judgement call. 9G or 16G, people per exit, it's a judgement with a number on it.
What's the stick force increase per G? It's some number somebody liked. Not sure what the low speed stall test runs on. Or an Airbus sidestick isn't stick force per G. How did they pass this test?
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:53 pm

aerolimani wrote:
PW100 wrote:
XRAYretired wrote:
Misrepresentation. Mr Markos strawman is to demonstrate compliance with the Longitudinal Stability requirements and to modify the FCC software to comply with the Stall Characteristics requirement - not to change the requirements.

The regulations are not a subjective attempt to quantify safety. The have been developed to improve safety (on the graves of many) and that is what they do.

Ray


. . . and to modify the FCC software to comply with the Stall Characteristics requirement . . .

In other words, put in software coding into the FCC introducing some level of FBW functionality for manual flight . . . that sounds like real a can of worms to me.
Not to mention that the the same FCC seemingly can't handle MCAS 2.0 coding and manual electric trimming at the same time, under certain conditions.

I'm sorry. I'm not following this, as it relates to the Jim Marko email. From what I read, he is advocating for a waiver. He doesn't say anything about changing regulations, nor about changing the way the software works. Regarding the software, he says that the version 12.1 MCAS is still not effective, as it does not meet the requirements of a more recently changed hazard assessment. As to the regulations, he says that eliminating MCAS brings about issues with handling and compliance, but that it looks like something they "could easily find a way to accept." I highly doubt that "accept" means changing regulations. It sounds like more of a "look the other way" policy, which in regulatory terms means a waiver.

The Block Diagram clearly states 'Prove Safe Handling Characteristics' not waive them. (keep watching out for the story tellers).

Ray
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:56 pm

XRAYretired wrote:
This includes a recognition that atmospheric disturbances occur that do not require the pilots assistance to push the airframe thought to stall rapidly.

Ray


And those atmospheric conditions that can cause those controls to get lighter than allowed by regulation are why you can't just rely on feel alone and why if the controls are just a little lighter than allowed by the regs it shouldn't really lead to a material decrease in safety. You must be constantly monitoring your instruments or your planes attitude with reference to something outside when you are at elevated angles of attack, and respect the stick shaker, the audio alarms the frame buffeting, etc...
 
Planetalk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:56 pm

rheinwaldner wrote:
And as images tell more than 1000 words, I quickly have drawn in the safety level of the MAX in the above diagram. To do this I even had to extend the scale of the diagram, as the safety level of the MAX reaches to heights not known after 1970 (where the diagram starts). The shown value for the MAX is 4550 fatalities per trillion RPKs:
Image

I get this number as follows:

- km per average flight: 2000
- MAX total flights: 250k
- pax on average: 150

This gives 75000000000 RPK.

Which is 1/13 of a trillion. 13 times the 350 fatalities yield the 4550 fatalities per trillion RPK.

This should answer, why we really should not focus on anything else than the MAX in this thread.


I have written many posts in this thread criticising those who repeatedly try to attach substantial blame to the pilots. I wholeheartedly disagree with morrissond.

However, I can't agree with your post here. You appear to be saying that because aviation is already extremely safe, we needn't worry about that small proportion of accidents that training could remedy. That attitude is not how aviation became as safe as it is.

The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

Yes Boeing rightly gets the blame for these crashes. They would not have happened if not for MCAS. However, in the spirit of avoiding future accidents, it would seem bizarre to me to insist that because of that, we should not apply any lessons about pilot training whatsoever, or seek to improve the standard of pilots. And I am quite sure the relevant authorities will not be thinking that way. Issues at LionAir have long been known, and while not the cause of this crash, it does shine a light on some deficiencies. Saying that takes nothing away from Boeing being culpable.

Now perhaps you would be perfectly happy getting on a Lionair flight. However, I avoided them based on what I knew before the crash, and I would still avoid them now unless I saw them making substantial changes. I really struggle to believe you genuinely think there is absolutely nothing to learn about pilot training or standards at the airline in the LionAir report.

Also worth noting that discussing pilot training is itself a criticism of Boeing because it was they that decided to deny pilots training on MCAS. This will obviously be changed with ungrounding, so it is a part of this. So if it helps, we can discuss Boeing and still be blaming Boeing ;)
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 9:59 pm

rheinwaldner wrote:
morrisond wrote:
But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier.

For the hundredth time, MCAS is not a warning system. It exists so the muscle memory of pilots is not fooled by the easing control force. MCAS is all about behavior and nothing about informing the pilots.


And for the hundreth time as Ray rightly pointed out above you can't rely on feel alone as atmospheric conditions can cause the controls to go light all by themselves. You must monitor your flight path to make sure it as intended.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:01 pm

Planetalk wrote:
rheinwaldner wrote:
And as images tell more than 1000 words, I quickly have drawn in the safety level of the MAX in the above diagram. To do this I even had to extend the scale of the diagram, as the safety level of the MAX reaches to heights not known after 1970 (where the diagram starts). The shown value for the MAX is 4550 fatalities per trillion RPKs:
Image

I get this number as follows:

- km per average flight: 2000
- MAX total flights: 250k
- pax on average: 150

This gives 75000000000 RPK.

Which is 1/13 of a trillion. 13 times the 350 fatalities yield the 4550 fatalities per trillion RPK.

This should answer, why we really should not focus on anything else than the MAX in this thread.


I have written many posts in this thread criticising those who repeatedly try to attach substantial blame to the pilots. I wholeheartedly disagree with morrissond.

However, I can't agree with your post here. You appear to be saying that because aviation is already extremely safe, we needn't worry about that small proportion of accidents that training could remedy. That attitude is not how aviation became as safe as it is.

The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

Yes Boeing rightly gets the blame for these crashes. They would not have happened if not for MCAS. However, in the spirit of avoiding future accidents, it would seem bizarre to me to insist that because of that, we should not apply any lessons about pilot training whatsoever, or seek to improve the standard of pilots. And I am quite sure the relevant authorities will not be thinking that way. Issues at LionAir have long been known, and while not the cause of this crash, it does shine a light on some deficiencies. Saying that takes nothing away from Boeing being culpable.

Now perhaps you would be perfectly happy getting on a Lionair flight. However, I avoided them based on what I knew before the crash, and I would still avoid them now unless I saw them making substantial changes. I really struggle to believe you genuinely think there is absolutely nothing to learn about pilot training or standards at the airline in the LionAir report.

Also worth noting that discussing pilot training is itself a criticism of Boeing because it was they that decided to deny pilots training on MCAS. This will obviously be changed with ungrounding, so it is a part of this. So if it helps, we can discuss Boeing and still be blaming Boeing ;)


Good post.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:08 pm

morrisond wrote:
flipdewaf wrote:
morrisond wrote:

Great post - as yes as long as they can keep from stalling an aircraft they should be safe flying a MAX even without MCAS. I believe US based pilots are now required to do stall training and Sims in the US have to be able to be stall capable.


But that’s the point, the Likelihood of stalling increases with the nonlinear (in the form reducing force per g) stick forces vs linear or positive increase per g. It’s like saying you don’t need engine fire suppression, just make sure the engines don’t catch fire.

If the nonlinearity is slight it may be a trivial increase in risk. But the regs are there for good reason.

Fred



Sent from my iPhone using Tapatalk



If the non-linearity is slight yes it is a slight increase in risk. But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier. You also have multiple other types of warnings triggering as well (stick shaker, audio alarms, frame buffeting) hopefully the Pilots would pay attention to one of them.

If not do they really don't belong in a ...........? I'll let you fill in the missing word.

MCAS is not the equivalent of a stick pusher that will prevent a stall.

Mr Lemme does not agree.
https://www.satcom.guru/2019/10/flawed- ... aster.html

'....Stall identification (augmentation) is an action - it is doing something to the airplane to push the nose down. Stick pushers and stick nudgers are commonly used for stall identification. A stick nudger would have performed nicely in place of MCAS, but that would have required redesign of the feel system. Speed Trim is performing a stall identification function.....'

Ray
 
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scbriml
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:08 pm

morrisond wrote:
scbriml wrote:
morrisond wrote:
Or why is there not a worldwide grounding of the frame until the issue is fixed?


You know why it hasn't been grounded.


Because it hasn't killed anyone yet? It sounds like they might have come close though. Is that really the standard now - people have to die before something that should be fixed it taken out of service?


Not even close. Think about why the MAX is grounded and the A320 isn't.
Time flies like an arrow. Fruit flies like a banana!
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kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:14 pm

Planetalk wrote:
The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

It is called cost efficiency.
Line pilots at airlines cannot be trained like astronauts, who spend months and years preparing for a single mission. And, while we're at it, as far as I know, exactly zero time of that training is spent dusting crops or towing banners in Cessna.
With the current aviation safety record, efficiency of any extra training has to be very high, and cost pretty low, to justify marginal improvement in safety. And yes, human life - as a risk of casualty - has a cost in engineering terms - as in amount of money we're willing to pay for reducing that risk, and that cost is not very high.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:27 pm

XRAYretired wrote:
morrisond wrote:
flipdewaf wrote:
But that’s the point, the Likelihood of stalling increases with the nonlinear (in the form reducing force per g) stick forces vs linear or positive increase per g. It’s like saying you don’t need engine fire suppression, just make sure the engines don’t catch fire.

If the nonlinearity is slight it may be a trivial increase in risk. But the regs are there for good reason.

Fred



Sent from my iPhone using Tapatalk



If the non-linearity is slight yes it is a slight increase in risk. But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier. You also have multiple other types of warnings triggering as well (stick shaker, audio alarms, frame buffeting) hopefully the Pilots would pay attention to one of them.

If not do they really don't belong in a ...........? I'll let you fill in the missing word.

MCAS is not the equivalent of a stick pusher that will prevent a stall.

Mr Lemme does not agree.
https://www.satcom.guru/2019/10/flawed- ... aster.html

'....Stall identification (augmentation) is an action - it is doing something to the airplane to push the nose down. Stick pushers and stick nudgers are commonly used for stall identification. A stick nudger would have performed nicely in place of MCAS, but that would have required redesign of the feel system. Speed Trim is performing a stall identification function.....'

Ray


Umm - I would agree with him - if you wanted a stall prevention system a stick pusher would have been a better solution.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:29 pm

kalvado wrote:
Planetalk wrote:
The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

It is called cost efficiency.
Line pilots at airlines cannot be trained like astronauts, who spend months and years preparing for a single mission. And, while we're at it, as far as I know, exactly zero time of that training is spent dusting crops or towing banners in Cessna.
With the current aviation safety record, efficiency of any extra training has to be very high, and cost pretty low, to justify marginal improvement in safety. And yes, human life - as a risk of casualty - has a cost in engineering terms - as in amount of money we're willing to pay for reducing that risk, and that cost is not very high.


But in this case it would probably require less training time to make sure pilots are proficient in stall recovery than how to deal with MCAS failures and multiple alarms going off.
 
flipdewaf
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:32 pm

morrisond wrote:
XRAYretired wrote:
morrisond wrote:


If the non-linearity is slight yes it is a slight increase in risk. But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier. You also have multiple other types of warnings triggering as well (stick shaker, audio alarms, frame buffeting) hopefully the Pilots would pay attention to one of them.

If not do they really don't belong in a ...........? I'll let you fill in the missing word.

MCAS is not the equivalent of a stick pusher that will prevent a stall.

Mr Lemme does not agree.
https://www.satcom.guru/2019/10/flawed- ... aster.html

'....Stall identification (augmentation) is an action - it is doing something to the airplane to push the nose down. Stick pushers and stick nudgers are commonly used for stall identification. A stick nudger would have performed nicely in place of MCAS, but that would have required redesign of the feel system. Speed Trim is performing a stall identification function.....'

Ray


Umm - I would agree with him - if you wanted a stall prevention system a stick pusher would have been a better solution.

What does a stick pusher do? How is it triggered? I feel like that story winds it’s way the same as MCAS...


Sent from my iPhone using Tapatalk
Image
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:32 pm

morrisond wrote:
XRAYretired wrote:
This includes a recognition that atmospheric disturbances occur that do not require the pilots assistance to push the airframe thought to stall rapidly.

Ray


And those atmospheric conditions that can cause those controls to get lighter than allowed by regulation are why you can't just rely on feel alone and why if the controls are just a little lighter than allowed by the regs it shouldn't really lead to a material decrease in safety. You must be constantly monitoring your instruments or your planes attitude with reference to something outside when you are at elevated angles of attack, and respect the stick shaker, the audio alarms the frame buffeting, etc...

Partial quotes are the province of the game players. Otherwise usual ignoring a significant reason for the regulations.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:48 pm

morrisond wrote:
kalvado wrote:
Planetalk wrote:
The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

It is called cost efficiency.
Line pilots at airlines cannot be trained like astronauts, who spend months and years preparing for a single mission. And, while we're at it, as far as I know, exactly zero time of that training is spent dusting crops or towing banners in Cessna.
With the current aviation safety record, efficiency of any extra training has to be very high, and cost pretty low, to justify marginal improvement in safety. And yes, human life - as a risk of casualty - has a cost in engineering terms - as in amount of money we're willing to pay for reducing that risk, and that cost is not very high.


But in this case it would probably require less training time to make sure pilots are proficient in stall recovery than how to deal with MCAS failures and multiple alarms going off.

Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not. In other words: there are no instructions available on increasing the winning chances in Russian roulette, but most places implement some flavor of weapon control.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 10:58 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
It is called cost efficiency.
Line pilots at airlines cannot be trained like astronauts, who spend months and years preparing for a single mission. And, while we're at it, as far as I know, exactly zero time of that training is spent dusting crops or towing banners in Cessna.
With the current aviation safety record, efficiency of any extra training has to be very high, and cost pretty low, to justify marginal improvement in safety. And yes, human life - as a risk of casualty - has a cost in engineering terms - as in amount of money we're willing to pay for reducing that risk, and that cost is not very high.


But in this case it would probably require less training time to make sure pilots are proficient in stall recovery than how to deal with MCAS failures and multiple alarms going off.

Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not. In other words: there are no instructions available on increasing the winning chances in Russian roulette, but most places implement some flavor of weapon control.


You are being overly dramatic - it is not Russian Roulette - stall should not be unrecoverable in any certified aircraft.

Recovery is actually now Mandated in the US - I think it is a good idea - in a sim.

If you feel the stick shaker, hear the alarms or feel the frame buffeting you probably have a good 10-30 seconds before you actually enter a stall - it won't happen in a split second. You have lots of time to prevent one.

Here is a great Video from Aviation Week detailing stalls in a 737. It's a 4 hour course with 15 stall recoveries that has to be completed by all US pilots by March next year I think.

https://www.youtube.com/watch?v=zCJco59tqoQ

If the MAX stalls like this I don't see what the problem is in deleting MCAS - it's takes an awful lot to get to full stall.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 11:10 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

But in this case it would probably require less training time to make sure pilots are proficient in stall recovery than how to deal with MCAS failures and multiple alarms going off.

Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not. In other words: there are no instructions available on increasing the winning chances in Russian roulette, but most places implement some flavor of weapon control.


You are being overly dramatic - it is not Russian Roulette - stall should not be unrecoverable in any certified aircraft.

Recovery is actually now Mandated in the US - I think it is a good idea - in a sim.

If you feel the stick shaker, hear the alarms or feel the frame buffeting you probably have a good 10-30 seconds before you actually enter a stall - it won't happen in a split second. You have lots of time to prevent one.

Here is a great Video from Aviation Week detailing stalls in a 737. It's a 4 hour course with 15 stall recoveries that has to be completed by all US pilots by March next year I think.

https://www.youtube.com/watch?v=zCJco59tqoQ

If the MAX stalls like this I don't see what the problem is in deleting MCAS - it's takes an awful lot to get to full stall.

1. How many injuries there would be in the back?
2. would pickle forks - or other force bearing components - survive such treatment?
3. Likely MAX is harsher anyway.
last, but not the least.. How many extra crashes we expect (optimistically) assuming 95% recovery success rate?
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Nov 25, 2019 11:15 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not. In other words: there are no instructions available on increasing the winning chances in Russian roulette, but most places implement some flavor of weapon control.


You are being overly dramatic - it is not Russian Roulette - stall should not be unrecoverable in any certified aircraft.

Recovery is actually now Mandated in the US - I think it is a good idea - in a sim.

If you feel the stick shaker, hear the alarms or feel the frame buffeting you probably have a good 10-30 seconds before you actually enter a stall - it won't happen in a split second. You have lots of time to prevent one.

Here is a great Video from Aviation Week detailing stalls in a 737. It's a 4 hour course with 15 stall recoveries that has to be completed by all US pilots by March next year I think.

https://www.youtube.com/watch?v=zCJco59tqoQ

If the MAX stalls like this I don't see what the problem is in deleting MCAS - it's takes an awful lot to get to full stall.

1. How many injuries there would be in the back?
2. would pickle forks - or other force bearing components - survive such treatment?
3. Likely MAX is harsher anyway.
last, but not the least.. How many extra crashes we expect (optimistically) assuming 95% recovery success rate?


You would never do this if people were in the back or practise this outside a SIM - you have 10-30 seconds before you even got to this point to push the control column forward.

They are practising this on A320 sims in the US as well.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 1:18 am

morrisond wrote:
kalvado wrote:
morrisond wrote:

But in this case it would probably require less training time to make sure pilots are proficient in stall recovery than how to deal with MCAS failures and multiple alarms going off.

Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not. In other words: there are no instructions available on increasing the winning chances in Russian roulette, but most places implement some flavor of weapon control.


You are being overly dramatic - it is not Russian Roulette - stall should not be unrecoverable in any certified aircraft.

Recovery is actually now Mandated in the US - I think it is a good idea - in a sim.

If you feel the stick shaker, hear the alarms or feel the frame buffeting you probably have a good 10-30 seconds before you actually enter a stall - it won't happen in a split second. You have lots of time to prevent one.

Here is a great Video from Aviation Week detailing stalls in a 737. It's a 4 hour course with 15 stall recoveries that has to be completed by all US pilots by March next year I think.

https://www.youtube.com/watch?v=zCJco59tqoQ

If the MAX stalls like this I don't see what the problem is in deleting MCAS - it's takes an awful lot to get to full stall.


Thinking about this if stall recovery training is complete by March of next year in the US and the MAX has no undiscovered handling issues without MCAS then you are basically good to go on removing MCAS and returning to service at least in the US. I would assume a great number of Pilots have taken the training already as it is required for all airliner types.

Probably making it a recurring thing (if not already mandated) every 2 or 3 years wouldn't be a bad idea.
 
JayinKitsap
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 1:49 am

beechnut wrote:
I'm beginning to wonder if even the end of 2020 is a realistic timeline for the re-certification of the MAX.

Clearly the MAX has some serious built-in aerodynamic deficiencies, and band-aid solutions so far do not seem to be working. The Transport Canada memo seems to be saying that either way it goes (MCAS or no MCAS), the MAX won't meet certification standards, but by removing MCAS, it will not be meeting standards in a somewhat less dangerous manner.

That is one big chunk to digest: half of the new-build narrow-bodies plying the skies would not meet certification standards.

If the TC engineer's analysis is correct, then hello Houston, we have a BIG problem. Or at least Boeing does, and I can't see how it can get past it.

That leaves two possibilities for the MAX to start carrying passengers again:

1) The TC engineer is wrong and it is possible to polish a turd;

2) The TC engineer is correct but the MAX returns to the skies on a non-technical (i.e. commercial) basis.

For Boeing's sake and for the sake of the industry, we'd better hope it's 1. And perhaps Boeing had better pull the NG blueprints out of the archives... they'd sell them simply because the market needs aircraft and Airbus can't fulfill all the market needs.

I have a hunch the MAX is dead. I would not have said that in March...

Beech


If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.
 
frmrCapCadet
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:09 am

Months ago it was obvious to many of us that MCAS could be just one of many safety features that created more hazards than it corrected. And equally obvious it wasn't the first and it won't be the last.
Buffet: the airline business...has eaten up capital...like..no other (business)
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:26 am

morrisond wrote:
flipdewaf wrote:
morrisond wrote:

Great post - as yes as long as they can keep from stalling an aircraft they should be safe flying a MAX even without MCAS. I believe US based pilots are now required to do stall training and Sims in the US have to be able to be stall capable.


But that’s the point, the Likelihood of stalling increases with the nonlinear (in the form reducing force per g) stick forces vs linear or positive increase per g. It’s like saying you don’t need engine fire suppression, just make sure the engines don’t catch fire.

If the nonlinearity is slight it may be a trivial increase in risk. But the regs are there for good reason.

Fred



Sent from my iPhone using Tapatalk



If the non-linearity is slight yes it is a slight increase in risk. But we have to remember that it (MCAS) would not actually prevent a stall - it is just one more warning system that you are getting close to one by making the controls heavier. You also have multiple other types of warnings triggering as well (stick shaker, audio alarms, frame buffeting) hopefully the Pilots would pay attention to one of them.

If not do they really don't belong in a ...........? I'll let you fill in the missing word.

MCAS is not the equivalent of a stick pusher that will prevent a stall.

Now I am seriously confused. Till now I thought mcas was a positive input system during manual flight and not just a warning system? I thought mcas would trim the nose to prevent stall, if It senses AOA is high, like happened in the 2 crashes ?
Boeing should just replicate the 2 similar incidents in actual flight by taping the AOA sensor over, in a unmodified max. Just calibrate the AOA sensor to show a higher than normal AOA.
Sims can't really cover everything. Remove all this useless guess work.
The pilots should of course be American.
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:34 am

JayinKitsap wrote:
beechnut wrote:
I'm beginning to wonder if even the end of 2020 is a realistic timeline for the re-certification of the MAX.

Clearly the MAX has some serious built-in aerodynamic deficiencies, and band-aid solutions so far do not seem to be working. The Transport Canada memo seems to be saying that either way it goes (MCAS or no MCAS), the MAX won't meet certification standards, but by removing MCAS, it will not be meeting standards in a somewhat less dangerous manner.

That is one big chunk to digest: half of the new-build narrow-bodies plying the skies would not meet certification standards.

If the TC engineer's analysis is correct, then hello Houston, we have a BIG problem. Or at least Boeing does, and I can't see how it can get past it.

That leaves two possibilities for the MAX to start carrying passengers again:

1) The TC engineer is wrong and it is possible to polish a turd;

2) The TC engineer is correct but the MAX returns to the skies on a non-technical (i.e. commercial) basis.

For Boeing's sake and for the sake of the industry, we'd better hope it's 1. And perhaps Boeing had better pull the NG blueprints out of the archives... they'd sell them simply because the market needs aircraft and Airbus can't fulfill all the market needs.

I have a hunch the MAX is dead. I would not have said that in March...

Beech


If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.

Too pessimistic. Boeing is going nowhere. It's in a sellers market. For comparison, VW has lost 18 b usd due to the pollution scandal. Its around 10 b usd for Boeing till now. And Boeing has a captive defence arm, with assured contracts.
Boeing just has to ensure that the max is as foolproof as its contemporaries before entering service. It has zero room for maneuver.
 
JayinKitsap
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:43 am

maint123 wrote:
JayinKitsap wrote:
beechnut wrote:
I'm beginning to wonder if even the end of 2020 is a realistic timeline for the re-certification of the MAX.

Clearly the MAX has some serious built-in aerodynamic deficiencies, and band-aid solutions so far do not seem to be working. The Transport Canada memo seems to be saying that either way it goes (MCAS or no MCAS), the MAX won't meet certification standards, but by removing MCAS, it will not be meeting standards in a somewhat less dangerous manner.

That is one big chunk to digest: half of the new-build narrow-bodies plying the skies would not meet certification standards.

If the TC engineer's analysis is correct, then hello Houston, we have a BIG problem. Or at least Boeing does, and I can't see how it can get past it.

That leaves two possibilities for the MAX to start carrying passengers again:

1) The TC engineer is wrong and it is possible to polish a turd;

2) The TC engineer is correct but the MAX returns to the skies on a non-technical (i.e. commercial) basis.

For Boeing's sake and for the sake of the industry, we'd better hope it's 1. And perhaps Boeing had better pull the NG blueprints out of the archives... they'd sell them simply because the market needs aircraft and Airbus can't fulfill all the market needs.

I have a hunch the MAX is dead. I would not have said that in March...

Beech


If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.

Too pessimistic. Boeing is going nowhere. It's in a sellers market. For comparison, VW has lost 18 b usd due to the pollution scandal. Its around 10 b usd for Boeing till now. And Boeing has a captive defence arm, with assured contracts.
Boeing just has to ensure that the max is as foolproof as its contemporaries before entering service. It has zero room for maneuver.


I for one expect the MAX to have RTS in the next few months. The Tech Advisory Board indicated the first step of certification is acceptable. Yes a lot needs to be cleaned up.

I was replying to beechnut that indicated that the MAX cannot be fixed and would not return to service for a long long time. If the MAX does not RTS, it would bankrupt Boeing. 4,000 planes x $50M of damages average per plane is $ 200B and Boeing is DEAD. In the cratering that follows possibly a dozen airlines would also collapse.
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 3:23 am

JayinKitsap wrote:
maint123 wrote:
JayinKitsap wrote:

If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.

Too pessimistic. Boeing is going nowhere. It's in a sellers market. For comparison, VW has lost 18 b usd due to the pollution scandal. Its around 10 b usd for Boeing till now. And Boeing has a captive defence arm, with assured contracts.
Boeing just has to ensure that the max is as foolproof as its contemporaries before entering service. It has zero room for maneuver.


I for one expect the MAX to have RTS in the next few months. The Tech Advisory Board indicated the first step of certification is acceptable. Yes a lot needs to be cleaned up.

I was replying to beechnut that indicated that the MAX cannot be fixed and would not return to service for a long long time. If the MAX does not RTS, it would bankrupt Boeing. 4,000 planes x $50M of damages average per plane is $ 200B and Boeing is DEAD. In the cratering that follows possibly a dozen airlines would also collapse.

Got your point. Frankly everyone is just guessing at this point and Boeing has not exactly been very upfront with its remedial actions. Until the plane again reenters service in large numbers, no one can make a informed judgement on its reliability. 700 odd max have been manufactured till date. And NG has a 20 % lower fuel efficiency than Max, so customers won't like changing over. Tough situation all over.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 4:18 am

JayinKitsap wrote:
maint123 wrote:
JayinKitsap wrote:

If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.

Too pessimistic. Boeing is going nowhere. It's in a sellers market. For comparison, VW has lost 18 b usd due to the pollution scandal. Its around 10 b usd for Boeing till now. And Boeing has a captive defence arm, with assured contracts.
Boeing just has to ensure that the max is as foolproof as its contemporaries before entering service. It has zero room for maneuver.


I for one expect the MAX to have RTS in the next few months. The Tech Advisory Board indicated the first step of certification is acceptable. Yes a lot needs to be cleaned up.

I was replying to beechnut that indicated that the MAX cannot be fixed and would not return to service for a long long time. If the MAX does not RTS, it would bankrupt Boeing. 4,000 planes x $50M of damages average per plane is $ 200B and Boeing is DEAD. In the cratering that follows possibly a dozen airlines would also collapse.


Why would they have to pay 4,000 frames times $50 million? I'm just curious about the logic behind your assumption? They could always build NG's.

However I do believe MAX does return to service - it's just whether or not it has no MCAS or MCAS V2.0
 
Chemist
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 5:05 am

It seems the problem for Boeing is that their point of view was "fix the offending MCAS". Which they have supposedly done.
But the fallout from the accidents and grounding is that investigators from all over are peeling back the onion and getting picky about a lot of other aspects of the aircraft and its certification. And that is taking more time and apparently increasing the scope of what Boeing needs to do to get the aircraft certification restored.

It will be interesting to see if they end up needing hardware changes in addition to software changes.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 6:14 am

morrisond wrote:
par13del wrote:
flipdewaf wrote:
Oh-good-fu*king-lord!!! If you can avoid having to comply with regulations because your solutions are bad then what’s the point in the regulations?

There has just been another fume event on the A320 I believe. If the Airbus solution of putting a sock in the pipe as a filter doesn’t work should should they just allow the time events to continue?

Solving this properly isn’t beyond the guys at Boeing, it’s a time and a cost issue.

Fred


Sent from my iPhone using Tapatalk

In the line of thinking with this thread the proper question would be why Airbus has not fixed the fume event and where is the AD from the regulators demanding a fix?
Boeing was attempting to meet the regulators requirements and they screwed up, unless there is no regulation requiring no fumes in the a/c?


Or why is there not a worldwide grounding of the frame until the issue is fixed?


No crash, no media attention, no grounding. The fume event in the A320 was more dangerous than MCAS, but it also showed the importance of correctly trained crews and how they are a key player for aviation safety. .
 
sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 6:25 am

AirBoat wrote:
As for testing with MCAS switched off. Just the switches wont do it, because mcas is still running in the background. It would take a menu in the flight computer software with an option of 'MCAS off'. This would probably take another 2 months to code up.
Does MCAS have any effect on the elevator?


I kind of like the closest-to-production sw configuration as possible, and if the FCC can run an extra process in the background (ie MCAS) with the cutout switches enabled, then that's better than a custom configuration.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 7:13 am

morrisond wrote:
XRAYretired wrote:
This includes a recognition that atmospheric disturbances occur that do not require the pilots assistance to push the airframe thought to stall rapidly.

Ray


And those atmospheric conditions that can cause those controls to get lighter than allowed by regulation are why you can't just rely on feel alone and why if the controls are just a little lighter than allowed by the regs it shouldn't really lead to a material decrease in safety. You must be constantly monitoring your instruments or your planes attitude with reference to something outside when you are at elevated angles of attack, and respect the stick shaker, the audio alarms the frame buffeting, etc...


I think it is important to add here something. In general even though we know the atmosphere pretty well certain non-linear events are hard to predict. This of course can lead to dangerous conditions for an aircraft to be in and can cause unusual movements and control forces for the pilot.

Now this is in general not a problem if the handling and "behavior" of the aircraft is predictable in as many scenarios as possible and even in the most crazy situations follows certain rules.

Now if we have an aircraft that has non-linear handling characteristics and somehow does not follow general rules within the flight envelope (even if it is only at the edge accoring to Boeing), this could and over time will lead to really dangerous situations when atmospheric disturbances push the frame into this edge of the envelope because then we have a non-linear handling aircraft in an atmosphere that is in itself non linear and unpredictable.

It should be every engineers goal to avoid a scenario like this and as we can not manipulate the atmosphere we can at least design an build an aircraft that does not have non linear handling characteristics. Boeing should be able to do that, or they were at least before the MAX.
 
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aerolimani
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 7:30 am

XRAYretired wrote:
aerolimani wrote:
PW100 wrote:

. . . and to modify the FCC software to comply with the Stall Characteristics requirement . . .

In other words, put in software coding into the FCC introducing some level of FBW functionality for manual flight . . . that sounds like real a can of worms to me.
Not to mention that the the same FCC seemingly can't handle MCAS 2.0 coding and manual electric trimming at the same time, under certain conditions.

I'm sorry. I'm not following this, as it relates to the Jim Marko email. From what I read, he is advocating for a waiver. He doesn't say anything about changing regulations, nor about changing the way the software works. Regarding the software, he says that the version 12.1 MCAS is still not effective, as it does not meet the requirements of a more recently changed hazard assessment. As to the regulations, he says that eliminating MCAS brings about issues with handling and compliance, but that it looks like something they "could easily find a way to accept." I highly doubt that "accept" means changing regulations. It sounds like more of a "look the other way" policy, which in regulatory terms means a waiver.

The Block Diagram clearly states 'Prove Safe Handling Characteristics' not waive them. (keep watching out for the story tellers).

Ray

"Proving safe handling characteristics" doesn't change the fact the MAX doesn't meet regulations. It would merely mean that the Boeing would have grounds on which to ask for a waiver.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 7:36 am

FluidFlow wrote:
morrisond wrote:
XRAYretired wrote:
This includes a recognition that atmospheric disturbances occur that do not require the pilots assistance to push the airframe thought to stall rapidly.

Ray


And those atmospheric conditions that can cause those controls to get lighter than allowed by regulation are why you can't just rely on feel alone and why if the controls are just a little lighter than allowed by the regs it shouldn't really lead to a material decrease in safety. You must be constantly monitoring your instruments or your planes attitude with reference to something outside when you are at elevated angles of attack, and respect the stick shaker, the audio alarms the frame buffeting, etc...


I think it is important to add here something. In general even though we know the atmosphere pretty well certain non-linear events are hard to predict. This of course can lead to dangerous conditions for an aircraft to be in and can cause unusual movements and control forces for the pilot.

Now this is in general not a problem if the handling and "behavior" of the aircraft is predictable in as many scenarios as possible and even in the most crazy situations follows certain rules.

Now if we have an aircraft that has non-linear handling characteristics and somehow does not follow general rules within the flight envelope (even if it is only at the edge accoring to Boeing), this could and over time will lead to really dangerous situations when atmospheric disturbances push the frame into this edge of the envelope because then we have a non-linear handling aircraft in an atmosphere that is in itself non linear and unpredictable.

It should be every engineers goal to avoid a scenario like this and as we can not manipulate the atmosphere we can at least design an build an aircraft that does not have non linear handling characteristics. Boeing should be able to do that, or they were at least before the MAX.


It is a strawman argument anyway. Certification requirements look at defined regular operating conditions. It is like saying "Oh, the brakes of our new car need 100m to stop the car from 100 km/h, this is okay because when the road is icy no car can stop faster..."
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 7:55 am

seahawk wrote:
FluidFlow wrote:
morrisond wrote:

And those atmospheric conditions that can cause those controls to get lighter than allowed by regulation are why you can't just rely on feel alone and why if the controls are just a little lighter than allowed by the regs it shouldn't really lead to a material decrease in safety. You must be constantly monitoring your instruments or your planes attitude with reference to something outside when you are at elevated angles of attack, and respect the stick shaker, the audio alarms the frame buffeting, etc...


I think it is important to add here something. In general even though we know the atmosphere pretty well certain non-linear events are hard to predict. This of course can lead to dangerous conditions for an aircraft to be in and can cause unusual movements and control forces for the pilot.

Now this is in general not a problem if the handling and "behavior" of the aircraft is predictable in as many scenarios as possible and even in the most crazy situations follows certain rules.

Now if we have an aircraft that has non-linear handling characteristics and somehow does not follow general rules within the flight envelope (even if it is only at the edge accoring to Boeing), this could and over time will lead to really dangerous situations when atmospheric disturbances push the frame into this edge of the envelope because then we have a non-linear handling aircraft in an atmosphere that is in itself non linear and unpredictable.

It should be every engineers goal to avoid a scenario like this and as we can not manipulate the atmosphere we can at least design an build an aircraft that does not have non linear handling characteristics. Boeing should be able to do that, or they were at least before the MAX.


It is a strawman argument anyway. Certification requirements look at defined regular operating conditions. It is like saying "Oh, the brakes of our new car need 100m to stop the car from 100 km/h, this is okay because when the road is icy no car can stop faster..."


I know but if your aircraft does not even comply or handle somehow like every other commercial aircraft within this operating conditions you can extrapolate it into the non regular operating conditions and can absolutely be sure it only gets worse and not magically handles great in them conditions.

It is therefore more like "Oh, there should be four brakes on our new car to stop the car from 100 km/h, but we only use one and augment the other three and this is okay because when the road is in perfect condition our car can stop..."
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 8:17 am

FluidFlow wrote:
seahawk wrote:
FluidFlow wrote:

I think it is important to add here something. In general even though we know the atmosphere pretty well certain non-linear events are hard to predict. This of course can lead to dangerous conditions for an aircraft to be in and can cause unusual movements and control forces for the pilot.

Now this is in general not a problem if the handling and "behavior" of the aircraft is predictable in as many scenarios as possible and even in the most crazy situations follows certain rules.

Now if we have an aircraft that has non-linear handling characteristics and somehow does not follow general rules within the flight envelope (even if it is only at the edge accoring to Boeing), this could and over time will lead to really dangerous situations when atmospheric disturbances push the frame into this edge of the envelope because then we have a non-linear handling aircraft in an atmosphere that is in itself non linear and unpredictable.

It should be every engineers goal to avoid a scenario like this and as we can not manipulate the atmosphere we can at least design an build an aircraft that does not have non linear handling characteristics. Boeing should be able to do that, or they were at least before the MAX.


It is a strawman argument anyway. Certification requirements look at defined regular operating conditions. It is like saying "Oh, the brakes of our new car need 100m to stop the car from 100 km/h, this is okay because when the road is icy no car can stop faster..."


I know but if your aircraft does not even comply or handle somehow like every other commercial aircraft within this operating conditions you can extrapolate it into the non regular operating conditions and can absolutely be sure it only gets worse and not magically handles great in them conditions.

It is therefore more like "Oh, there should be four brakes on our new car to stop the car from 100 km/h, but we only use one and augment the other three and this is okay because when the road is in perfect condition our car can stop..."



That is why they need to test it without MCAS.

To use the Car analogy On dry roads from 60 mph the MAX stops within the regulated limit of 150', on icy roads you are allowed 200' and the MAX with MCAS does it within 200' at 197'. Without MCAS we think it takes 201', so maybe this is not so bad and maybe we should allow it - but if testing shows its takes 300' then that is another matter.

Maybe that is why was reportedly test flying the MAX again this weekend and doing stalls - they were seeing how close they could get to 200' without MCAS but possibly just cranking up the STS system as much as possible - I'm just speculating on this.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 8:26 am

morrisond wrote:
FluidFlow wrote:
seahawk wrote:

It is a strawman argument anyway. Certification requirements look at defined regular operating conditions. It is like saying "Oh, the brakes of our new car need 100m to stop the car from 100 km/h, this is okay because when the road is icy no car can stop faster..."


I know but if your aircraft does not even comply or handle somehow like every other commercial aircraft within this operating conditions you can extrapolate it into the non regular operating conditions and can absolutely be sure it only gets worse and not magically handles great in them conditions.

It is therefore more like "Oh, there should be four brakes on our new car to stop the car from 100 km/h, but we only use one and augment the other three and this is okay because when the road is in perfect condition our car can stop..."



That is why they need to test it without MCAS.

To use the Car analogy On dry roads from 60 mph the MAX stops within the regulated limit of 150', on icy roads you are allowed 200' and the MAX with MCAS does it within 200' at 197'. Without MCAS we think it takes 201', so maybe this is not so bad and maybe we should allow it - but if testing shows its takes 300' then that is another matter.

Maybe that is why was reportedly test flying the MAX again this weekend and doing stalls - they were seeing how close they could get to 200' without MCAS but possibly just cranking up the STS system as much as possible - I'm just speculating on this.


For which imho is no technical argument to be made. Grandfathering usually means that your old design did meet old standards and it would be excessive to demand the adjustment to new standards for an old design certified in the past. In that case however that argument can not be made, as all 737s prior to the MAX do meet the requirement. In addition we already know that they have been looking at aerodynamic changes like strakes to counter the effect, but those do come with a penalty in fuel burn, so they were not a good option for the OEM, but that must not concern the regulator.
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 8:27 am

morrisond wrote:
FluidFlow wrote:
seahawk wrote:

It is a strawman argument anyway. Certification requirements look at defined regular operating conditions. It is like saying "Oh, the brakes of our new car need 100m to stop the car from 100 km/h, this is okay because when the road is icy no car can stop faster..."


I know but if your aircraft does not even comply or handle somehow like every other commercial aircraft within this operating conditions you can extrapolate it into the non regular operating conditions and can absolutely be sure it only gets worse and not magically handles great in them conditions.

It is therefore more like "Oh, there should be four brakes on our new car to stop the car from 100 km/h, but we only use one and augment the other three and this is okay because when the road is in perfect condition our car can stop..."



That is why they need to test it without MCAS.

To use the Car analogy On dry roads from 60 mph the MAX stops within the regulated limit of 150', on icy roads you are allowed 200' and the MAX with MCAS does it within 200' at 197'. Without MCAS we think it takes 201', so maybe this is not so bad and maybe we should allow it - but if testing shows its takes 300' then that is another matter.


I have this strange feeling that without MCAS the MAX does not brake at all...

If it would within 201m then Boeing would have published this and also advocated for getting an exemption. That would have been the cheapest and easiest even before all the troubles. The fact that they did not and also seem to never ever showed anyone how the MAX performed without gives me the impression it is really bad. They now have to show it and I hope they do not "Dieselgate" that test flight by manipulating the software to help pass the tests. The fact that they actually have to change the software means that only with manual trim the aircraft is not safe. So flipping the switches is not the way to go and it seems Boeing will make manual electric trim available with MCAS off for them test flights to be safe. I can not think of another reason why it is not possible to just flip the switches and test the frame.
 
Armodeen
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 8:28 am

Good post, you are bang on.

Planetalk wrote:
rheinwaldner wrote:
And as images tell more than 1000 words, I quickly have drawn in the safety level of the MAX in the above diagram. To do this I even had to extend the scale of the diagram, as the safety level of the MAX reaches to heights not known after 1970 (where the diagram starts). The shown value for the MAX is 4550 fatalities per trillion RPKs:
Image

I get this number as follows:

- km per average flight: 2000
- MAX total flights: 250k
- pax on average: 150

This gives 75000000000 RPK.

Which is 1/13 of a trillion. 13 times the 350 fatalities yield the 4550 fatalities per trillion RPK.

This should answer, why we really should not focus on anything else than the MAX in this thread.


I have written many posts in this thread criticising those who repeatedly try to attach substantial blame to the pilots. I wholeheartedly disagree with morrissond.

However, I can't agree with your post here. You appear to be saying that because aviation is already extremely safe, we needn't worry about that small proportion of accidents that training could remedy. That attitude is not how aviation became as safe as it is.

The morrisond gap as you call it is made up of dead bodies. Aviation should always be looking at any ways to improve safety and in any accident absolutely any lessons that emerge should be studied and if necessary acted upon, whether they are the primary cause, or simply something that happened to occur on that flight that no-one would have ever thought about if it hadn't crashed. That doesn't necessarily even have to be someone doing anything wrong, just the fact that flight was investigated offers an opportunity to learn something.

Yes Boeing rightly gets the blame for these crashes. They would not have happened if not for MCAS. However, in the spirit of avoiding future accidents, it would seem bizarre to me to insist that because of that, we should not apply any lessons about pilot training whatsoever, or seek to improve the standard of pilots. And I am quite sure the relevant authorities will not be thinking that way. Issues at LionAir have long been known, and while not the cause of this crash, it does shine a light on some deficiencies. Saying that takes nothing away from Boeing being culpable.

Now perhaps you would be perfectly happy getting on a Lionair flight. However, I avoided them based on what I knew before the crash, and I would still avoid them now unless I saw them making substantial changes. I really struggle to believe you genuinely think there is absolutely nothing to learn about pilot training or standards at the airline in the LionAir report.

Also worth noting that discussing pilot training is itself a criticism of Boeing because it was they that decided to deny pilots training on MCAS. This will obviously be changed with ungrounding, so it is a part of this. So if it helps, we can discuss Boeing and still be blaming Boeing ;)
 
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scbriml
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 8:38 am

FluidFlow wrote:
I have this strange feeling that without MCAS the MAX does not brake at all...


So even more 737 landing overruns? :wink2:
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art
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 9:23 am

kalvado wrote:
Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not.


I am mystified. I can see that stall recovery may take time and cost altitude but what is so vicious that entering and recovering from a stall can be likened to Russian roulette?
 
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SomebodyInTLS
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 10:11 am

art wrote:
kalvado wrote:
Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not.


I am mystified. I can see that stall recovery may take time and cost altitude but what is so vicious that entering and recovering from a stall can be likened to Russian roulette?


It is a golden rule that you don't stall an airliner under any circumstances. Just too dangerous and unpredictable.

As an example of the extreme behaviour you can encounter otherwise, see what test pilots experience in test conditions:

https://youtu.be/L2CsO-Vu7oc

That's why all training and procedures are about dealing with APPROACH to stall, not actual stall. People who say otherwise are wrong.
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morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 12:37 pm

scbriml wrote:
FluidFlow wrote:
I have this strange feeling that without MCAS the MAX does not brake at all...


So even more 737 landing overruns? :wink2:


Good one!
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 12:48 pm

SomebodyInTLS wrote:
art wrote:
kalvado wrote:
Stall recovery in an airliner is a Russian roulette. That is why stall avoidance is trained, recovery is not.


I am mystified. I can see that stall recovery may take time and cost altitude but what is so vicious that entering and recovering from a stall can be likened to Russian roulette?


It is a golden rule that you don't stall an airliner under any circumstances. Just too dangerous and unpredictable.

As an example of the extreme behaviour you can encounter otherwise, see what test pilots experience in test conditions:

https://youtu.be/L2CsO-Vu7oc

That's why all training and procedures are about dealing with APPROACH to stall, not actual stall. People who say otherwise are wrong.


Yes training to never get in a stall is the best idea as not many jurisdictions teach how to get out of what was shown in that video.

You never want to get close to a real stall - however it's pretty easy to avoid.

That video did not show a stall - that was a spin. And yes if it at stall entry the MAX is not benign like what was shown in the Aviation Week video I posted and if stall develops into a spin unprovoked and looks like the 717 you posted (you can see the pilot actively putting it into a spin intentionally it did not happen without pilot input) then the MAX should probably not be allowed to fly again.

However if you were trained in the Canadian system you do learn how to recover from Spins - it's a normal part of training and a lot of fun.

Which makes dealing with Stalls a total non-event (they are very boring) as you understand how to deal with what can potentially happen after stall if you are not careful.
 
art
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 1:58 pm

Re: stalls and spins, thanks for the info.

Can I take it that no airliners are lost through stalling? I don't include AF447 when I ask that or take off/landing accidents due to wing icing/wind shear.

Anyway, sorry to go off topic. Just curious since I did stalls and spins in a light aerobatic aircraft in good visibility and learning to recover did not take long at all.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:15 pm

art wrote:
Re: stalls and spins, thanks for the info.

Can I take it that no airliners are lost through stalling? I don't include AF447 when I ask that or take off/landing accidents due to wing icing/wind shear.

Anyway, sorry to go off topic. Just curious since I did stalls and spins in a light aerobatic aircraft in good visibility and learning to recover did not take long at all.


I did a cursory look through the last 10 years or so and the only fatal accidents that appear to have resulted from a stall appear to be:

ET409 - An 737 NG - In the end he stalled it - but his airmanship was so bad he probably didn't belong in a cockpit - or he might have been drunk or incapacitated.

AF447 - A330 - As you mentioned - Non-back driven FBW was probably a major contributor as the Pilots were fighting each others control inputs.

AirAsia 8501 - A320 - Basically the same as AF447 - loss of protections of Primary law and the pilots not knowing what each other was doing.

After 8501 Indonesia came out with a slew of recommendations on Maintenance practices and crew CRM which Lionair seems to have totally ignored.
 
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InsideMan
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 2:43 pm

morrisond wrote:
JayinKitsap wrote:
maint123 wrote:
Too pessimistic. Boeing is going nowhere. It's in a sellers market. For comparison, VW has lost 18 b usd due to the pollution scandal. Its around 10 b usd for Boeing till now. And Boeing has a captive defence arm, with assured contracts.
Boeing just has to ensure that the max is as foolproof as its contemporaries before entering service. It has zero room for maneuver.


I for one expect the MAX to have RTS in the next few months. The Tech Advisory Board indicated the first step of certification is acceptable. Yes a lot needs to be cleaned up.

I was replying to beechnut that indicated that the MAX cannot be fixed and would not return to service for a long long time. If the MAX does not RTS, it would bankrupt Boeing. 4,000 planes x $50M of damages average per plane is $ 200B and Boeing is DEAD. In the cratering that follows possibly a dozen airlines would also collapse.


Why would they have to pay 4,000 frames times $50 million? I'm just curious about the logic behind your assumption? They could always build NG's.

However I do believe MAX does return to service - it's just whether or not it has no MCAS or MCAS V2.0


They could build NGs and offer them and substantial rebates. Any delay / failure to deliver is part of a large renegotiation and you can't just stick to the contract as is. No airline wants Boeing to go bankrupt. The sunk cost for the already built MAX however would make a huge dent in the Boeing P/L 400 delivered plus 400 built plus damages is not 200 billion but maybe 50 in total is not far off....
 
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767333ER
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 3:27 pm

morrisond wrote:
Non-back driven systems have been one of the primary causes of more fatalities than MCAS.

Again, baseless and absolutely false claim. AF447 is not proof of this because we don’t know in these cases whether back driven controls would make a difference. I argue not. AF447 for example the two flying were both freaking out and weren’t thinking straight or at all in a good frame of mind. How do we know they wouldn’t just fight each other if the controls are linked or back driven? Well we don’t because that’s human factors, a very difficult rabbit hole to go down. At best the control architecture was a contributing cause and was said to be as much in the report. Sadly for some folks because only Airbus does it this way and because Sully said so having it as a primary cause is fact.

I have heard the opinions of various qualified people that fly commercial aircraft and they all generally are in line with what I say. Flying 100-some hours on a C172 won’t teach you the first thing about operating commercial aircraft or human factors.

Yet again this is not relevant in the discussion and you are arguing off point.
JayinKitsap wrote:
beechnut wrote:
I'm beginning to wonder if even the end of 2020 is a realistic timeline for the re-certification of the MAX.

Clearly the MAX has some serious built-in aerodynamic deficiencies, and band-aid solutions so far do not seem to be working. The Transport Canada memo seems to be saying that either way it goes (MCAS or no MCAS), the MAX won't meet certification standards, but by removing MCAS, it will not be meeting standards in a somewhat less dangerous manner.

That is one big chunk to digest: half of the new-build narrow-bodies plying the skies would not meet certification standards.

If the TC engineer's analysis is correct, then hello Houston, we have a BIG problem. Or at least Boeing does, and I can't see how it can get past it.

That leaves two possibilities for the MAX to start carrying passengers again:

1) The TC engineer is wrong and it is possible to polish a turd;

2) The TC engineer is correct but the MAX returns to the skies on a non-technical (i.e. commercial) basis.

For Boeing's sake and for the sake of the industry, we'd better hope it's 1. And perhaps Boeing had better pull the NG blueprints out of the archives... they'd sell them simply because the market needs aircraft and Airbus can't fulfill all the market needs.

I have a hunch the MAX is dead. I would not have said that in March...

Beech


If the MAX is dead, Boeing Commercial would be heading to Chapter 7 bankruptcy, 75K employees would be on the street, Boeing Defense would be sold, and Airbus will have a full monopoly. For aviation fans it means several decades with just the current models flying. It's good you are so optimistic.

I don’t think it will die myself because I don’t think it can die. Boeing cannot die. The government relies on them for defense contracts and they have their fingers in on the government. They’d probably get a massive bailout if the MAX were to be dead. They would also probably have several choices that they could exercise on the MAX that would change its certification, but would probably fix it for cheaper than throwing it out. If they did die out, Airbus would have a monopoly for a few years before the people from failed Boeing reorganize and come back.

If it took that much for the guilty management to go to prison though, it would be worth it.
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 3:40 pm

seahawk wrote:
morrisond wrote:
par13del wrote:
In the line of thinking with this thread the proper question would be why Airbus has not fixed the fume event and where is the AD from the regulators demanding a fix?
Boeing was attempting to meet the regulators requirements and they screwed up, unless there is no regulation requiring no fumes in the a/c?


Or why is there not a worldwide grounding of the frame until the issue is fixed?


No crash, no media attention, no grounding. The fume event in the A320 was more dangerous than MCAS, but it also showed the importance of correctly trained crews and how they are a key player for aviation safety. .

Are you implying/suggesting that a Lionair crew would probably crashed?
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morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 4:02 pm

767333ER wrote:
morrisond wrote:
Non-back driven systems have been one of the primary causes of more fatalities than MCAS.

Again, baseless and absolutely false claim. AF447 is not proof of this because we don’t know in these cases whether back driven controls would make a difference. I argue not. AF447 for example the two flying were both freaking out and weren’t thinking straight or at all in a good frame of mind. How do we know they wouldn’t just fight each other if the controls are linked or back driven? Well we don’t because that’s human factors, a very difficult rabbit hole to go down. At best the control architecture was a contributing cause and was said to be as much in the report. Sadly for some folks because only Airbus does it this way and because Sully said so having it as a primary cause is fact.

I have heard the opinions of various qualified people that fly commercial aircraft and they all generally are in line with what I say. Flying 100-some hours on a C172 won’t teach you the first thing about operating commercial aircraft or human factors.

Yet again this is not relevant in the discussion and you are arguing off point.



You may be right - we can't know for sure. However, I'm pretty sure though there has never been a stall that led to a fatal crash in an FBW aircraft that had back driven or at least linked controls.

So human factors as contributing cause are allowed on AF447 but not on Lionair or ET302?

Yes some 100 hours in a 172 won't teach you much about operating commercial aircraft or human factors - nor should slightly more hours qualify you to fly a 737 or A320. If you did do those hours in Canada though you would have a pretty good idea how to unstall an aircraft or get out of a Spin.

The point is as long as the MAX doesn't have some unknown aerodynamic behaviour that causes non-normal stall behavior it should be fine without MCAS and without FBW with the skills all Commercial Pilots should have.

A stall is a lot easier to figure out than multiple alarms going off and the plane doing weird things (MCAS effects).
 
djm18
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Nov 26, 2019 4:40 pm

Bjorn’s Corner: Analysing the Lion Air JT610 crash, Part 2.

November 8, 2019, ©. Leeham News: We started the series on analyzing the Lion Air JT610 crash based on the final crash report last week by looking at what went wrong with the aircraft’s Angle of Attack sensors.

https://leehamnews.com/2019/11/08/bjorn ... sh-part-2/

Again, the below is a direct quote from Bjorn's Corner Lion Air Crash Analysis Part 2. It seems to me it helps to some degree frame much of the discussion taking place:



"MCAS, a system which should never activate"

"It’s also important to understand MCAS is a system augmenting the behavior of the MAX way outside the normal flight envelope. In daily operation, a 737 MAX flies with an Angle of Attack below 7° to 8° and never passes 1.2 G in load factor (in fact it rarely passes 1.15 G, the load factor for a 30° bank turn)."

"MCAS is programmed to activate at almost double this AoA value and the pilot need to pull around 2G or more to get to where MCAS will be active. No person would stand up in the cabin if the pilot is flying like this. A mega-crisis situation is needed for an airliner pilot to need to pull 2Gs or more. I know no airliner pilot which has been even close to 2G during their flying of airliners in regular operation. Test pilots can reach these values to control the correct behavior of a new or repaired aircraft but even this is rare."

"You only go to this corner of the flight envelope if the aircraft is in the utmost crisis. As MCAS is only needed when the wing is clean (no slats or flaps deployed), this means you are turning extremely hard to avoid a mid-air collision or maneuvering through extreme turbulence. If you hit clear air turbulence, you don’t maneuver as a pilot as this can worsen the effect of the turbulence. The only case where maneuvering might be needed is when passing strong wake turbulence of another aircraft (you can get a strong change in pitch and roll angle). But even then 2 G or more and more than 10° AoA is extreme maneuvering."

"The consequence is, the likelihood an airliner pilot ever running into a situation where a correctly triggered MCAS would go active is highly improbable."

"This is described to give context to why FAA accepted Boeing’s suggestion MCAS didn’t need to be described to the pilots. I don’t endorse this decision by writing the above. But as said, we need the correct context to be able to form a correct opinion. We can’t ask people to understand what is normal and what is abnormal in an airliner’s operation if we don’t spend time describing it."

"And if we don’t understand the unlikely event of MCAS ever going active when correctly triggered, we don’t understand the system and its implementation. (For those who think I’m writing this to later defend MCAS in its initial implementation, I’m not. It was awful and we will come to that.)"

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