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767333ER
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 5:29 am

PixelFlight wrote:
XRAYretired wrote:
Well, here an unexpected turn. A Transport Canada chappie has gone 'off piste' and written to the other regulators calling for the total removal of MCAS!

https://www.nytimes.com/2019/11/22/busi ... 7-max.html

Ray
:thumbsup:

Key part of the article:
“The only way I see moving forward at this point, is that MCAS has to go,” the official, Jim Marko, the manager in aircraft integration and safety assessment at Transport Canada Civil Aviation, wrote in the email. He sent the email on Tuesday to officials at the Federal Aviation Administration, the European Union Aviation Safety Agency and Brazil’s National Civil Aviation Agency.

Linh Le, a system safety manager at the F.A.A., shared Mr. Marko’s message with others at the agency. He noted that the Canadian official believed that “MCAS introduces catastrophic hazards that weren’t there before,” that “it and the fix add too much complexity,” that “there have been many revisions to the software” and that “each was a band-aid.”

Mr. Le said he had similar misgivings about Boeing’s proposed fix for the Max. “I have held similar perspective (questioning the need for MCAS, at least from the system safety standpoint),” he said in the email to colleagues. It is unclear whether international regulators will take any action in response to Mr. Marko’s concerns.

Seem to be at a pretty high level of expertise. This could be an other indication that the real data about the 737-8/9 MAX longitudinal stability without MCAS in some specific situations is still not in hand of the regulators. Because this is a real contradiction to me: if the MCAS could be removed so easily, how Boeing could have missed that opportunity in the first place ? A really strange situation.

That said, I found even more strange that such experts did not even talk about the trim wheel at high speed.

I hope they stand firm and do not get pushed over. If there is a way to nip the risk of MCAS in the bud it should be done.
Been on: 732 733 734 73G 738 752 763 A319 A320 A321 CRJ CR7 CRA/CR9 E145 E175 E190 F28 MD-82 MD-83 C172R C172S P2006T PA-28-180

2 ears for spatial hearing, 2 eyes for depth perception, 2 ears for balance... How did Boeing think 1 sensor was good enough?!
 
shmerik
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 5:49 am

Actual email and attachments available over at theaircurrent...

https://theaircurrent.com/aviation-safe ... m-737-max/

Image

Image

Reading the entire thing rather than the quotes provided above makes it seem like a more serious issue than just another agency trying to present with good optics (showing off that they're taking this seriously). Sounds like Boeing's fixes may not be coming along as smoothly as the press releases have let on. Specifically the bits referring to "not knowing the reasons that 12.1 is not effective" and that it was "another point that was just discovered".
 
DenverTed
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:40 am

If they got MCAS to work on the 767, I wonder why it is so problematic on the 737?
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 7:26 am

Revelation wrote:
seahawk wrote:
JT was not grounded, because they did not crash 2 planes in a short time. The MAX was grounded because 2 very similar looking crashes happened within a short period by modern safety standards.

Ok, I'll add one vote to the "trust in the law of big numbers" / "wait till the next crash" column..


Considering the fact that pilots were reporting control difficulties and technical problems, grounding the airline for insufficient pilot training still does not seem obvious to me. After the final report, the airline should have been closed though.
 
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aerolimani
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 9:06 am

par13del wrote:
dtw2hyd wrote:
Sometimes I feel there was a mixup between MAX and 777X programs.

Should have spent maximum R&D dollars on clean slate narrowbody with CFRP, folding wingtips, full FBW... and minimum development dollars just to slap new engines on 77W. BCA did the exact opposite.

It is a pain to watch the current fiasco.

What the fiasco shows is that Boeing could have survived financially spending the funds for a clean sheet to eliminate the limitations of the 737 using existing engine tech to simply match the A32X series.

That’s always sounded like a lame duck to me. With all the time that’s passed, Boeing couldn’t have designed a sufficiently more efficient aircraft because engine tech hasn’t come far enough? Come on!

Share buybacks, increasing shareholder value, executive bonuses, and keeping Boeing’s legal department busy, were all given a higher priority than actually designing a decent product. That was the real aim of the C-suite, and the rhetoric was likely crafted to reflect their priorities. You pay for some studies to be done, and you tell them what you want the outcome to be.
 
mjoelnir
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 9:42 am

DenverTed wrote:
If they got MCAS to work on the 767, I wonder why it is so problematic on the 737?


An ancient computer system perhaps? And if they start to change avionics, the reasons for keeping exemptions from the rules disappear. And than you have to do serious changes. And you can not sell the frame as unchanged any longer. And you have to accept that training, including simulator training, is needed to move from the NG to the MAX. Imagine the horror.
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 9:56 am

If MCAS failure is now classified as "catastrophic" they might need additional system redundancy they hadn't installed before for the lower risk assessment they originally had?
 
ACATROYAL
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 10:45 am

Being Canadian... I love our response from the Canadian authorities investigating the MCAS on the Max as retweeted by Jon Ostrower form the Air Current Simply remove it entirely from the plane! Two things with this statement.

https://twitter.com/jonostrower
"UPDATED: Transport Canada safety official urges removal of MCAS from 737 Max
Transport Canada safety official urges removal of MCAS from 737 Max
A Transport Canada safety official in an email to his counterparts in the United States, Europe and Brazil outlined his misgivings about the revised
[/i]"[/i]

1. After all this time MCAS is still raising red flags!!
2, Can it actually be removed and make the plane safe...or safer to fly?
 
Oykie
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 11:15 am

I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 12:14 pm

Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

I've been saying for months the MAX could be a lot safer overall without MCAS.

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.
 
Oykie
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 12:33 pm

morrisond wrote:
Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

I've been saying for months the MAX could be a lot safer overall without MCAS.

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.


Thank you for a good explanation. Would it then be possible to have the MAX with disabled MCAS for Canada only?
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
 
dtw2hyd
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 12:55 pm

Interesting late Friday development. What now? TC cannot be brushed aside because Canada is not a third world country. Maybe a disgruntled employee tag.
All posts are just opinions.
 
checklist350
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 1:01 pm

ACATROYAL wrote:
Being Canadian... I love our response from the Canadian authorities investigating the MCAS on the Max as retweeted by Jon Ostrower form the Air Current Simply remove it entirely from the plane! Two things with this statement.

https://twitter.com/jonostrower
"UPDATED: Transport Canada safety official urges removal of MCAS from 737 Max
Transport Canada safety official urges removal of MCAS from 737 Max
A Transport Canada safety official in an email to his counterparts in the United States, Europe and Brazil outlined his misgivings about the revised
[/i]"[/i]

1. After all this time MCAS is still raising red flags!!
2, Can it actually be removed and make the plane safe...or safer to fly?


The most significant takeaway for me is that the "final decisions on acceptance will not be technically based."

Note he did not say "may". This does not engender trust in the recertification process.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 1:02 pm

The proposal comes with a big if "Prove safe Handling Characteristics" without MCAS. So far Boeing stayed far away from talking about the handling without MCAS - maybe for a good reason?
 
randomdude83
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 1:21 pm

There has got to be some form of data from all the frames that flown or even from test flights that shows the actual use or engagement of the MCAS on standard flights. Obviously the two accidents that happened were caused by a Failed sensor and Boeing can always create redundancy there (two sensors for AOA, etc) but, the actual question I have based on the Canadian email proposal is, if the AOA sensors work like they should, did any of the flights ever engage the MCAS?

If that is a NO, I think the Canadian email proposal is sound and should be considered by Boeing. I think it just depends on an actual Data showing that the MCAS did/did not engage with a working AOA sensor in a standard or even a testy flight.

And Naturally, our full Trust in our Pilots to understand the Characteristics of a 737MAX without MCAS.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 1:30 pm

shmerik wrote:
Actual email and attachments available over at theaircurrent...

https://theaircurrent.com/aviation-safe ... m-737-max/

Image

Image

Reading the entire thing rather than the quotes provided above makes it seem like a more serious issue than just another agency trying to present with good optics (showing off that they're taking this seriously). Sounds like Boeing's fixes may not be coming along as smoothly as the press releases have let on. Specifically the bits referring to "not knowing the reasons that 12.1 is not effective" and that it was "another point that was just discovered".
:thumbsup: :checkmark: Thanks, this is interesting information.

What is the exact meaning of CAT in this context ?

The mail support some points:
* The discrete architecture is challenging (obsolete ?) for safety critical augmentation system.
* The 737-8/9 MAX longitudinal stability at "windup turn maneuver flaps 0" is non-compliant .
* The 737-8/9 MAX stall identification at "flap 0" is non-compliant.
* The authorities still don't have any clue of the actual 737-8/9 MAX handling characteristics without MCAS.

I found the last point really alarming. The handling characteristics without MCAS is the absolute central point that justified the MCAS existence and should have defined the requirements for the MCAS design. But where are those requirements ? I don't remember having read them in the NTSB review. Just that the handling characteristics is unacceptable, without any details of what must be corrected.

I share the worries of the email author. The picture available to the public look like the Boeing "industry standard" can't be trusted without majors changes, and that the regulators are running behind almost in the black... If the RTS will be be technically based, this will destroy any remaining credibility.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
flipdewaf
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 2:41 pm

morrisond wrote:
Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

That is pretty weird, it’s either needed or not right? I had heard that there was the potential to allow one MCAS application per high AoA event.

morrisond wrote:

I've been saying for months the MAX could be a lot safer overall without MCAS.

That’s totally illogical from a safety perspective though. If the solution to the handling issue is more dangerous than the handling characteristic that doesn’t mean we should accept the handling characteristic, it means you need a different solution.

If my solution so stop someone burning themselves on a hot pipe at work is to have a pit bull that rips your arm off of you get too close does not mean that we should remove the pit bull and just accept that people can burn themselves.

morrisond wrote:

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.


There are no magic bullets, there are reasonable improvements hat add to the safety of the system, FBW being one of them.
morrisond wrote:

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.


I wasn’t aware of the controls going light in turbulence. The reason why the control ‘feel’ is so important is because the human body is much better at force based proprioception than displacement proprioception.

Sorry Morrisond I feel I’m picking on you, I’m not, you just being up interesting points that I can look up and answer to on my phone.

Fred


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

Sat Nov 23, 2019 3:06 pm

morrisond wrote:
Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

I've been saying for months the MAX could be a lot safer overall without MCAS.

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.

Mis-interpretation of described MCAS V2.0 function, to identify a non-catastrophic condition, leading to usual off topic global training standards guff.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 3:25 pm

flipdewaf wrote:
morrisond wrote:
Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

That is pretty weird, it’s either needed or not right? I had heard that there was the potential to allow one MCAS application per high AoA event.

morrisond wrote:

I've been saying for months the MAX could be a lot safer overall without MCAS.

That’s totally illogical from a safety perspective though. If the solution to the handling issue is more dangerous than the handling characteristic that doesn’t mean we should accept the handling characteristic, it means you need a different solution.

If my solution so stop someone burning themselves on a hot pipe at work is to have a pit bull that rips your arm off of you get too close does not mean that we should remove the pit bull and just accept that people can burn themselves.

morrisond wrote:

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.


There are no magic bullets, there are reasonable improvements hat add to the safety of the system, FBW being one of them.
morrisond wrote:

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.


I wasn’t aware of the controls going light in turbulence. The reason why the control ‘feel’ is so important is because the human body is much better at force based proprioception than displacement proprioception.

Sorry Morrisond I feel I’m picking on you, I’m not, you just being up interesting points that I can look up and answer to on my phone.

Fred


Sent from my iPhone using Tapatalk


No worries at all.

The big question is does the MAX have handling issues that aren't that benign. If it does then the best solution is probably to put a bullet into it. If not and the controls just get lighter than allowed (and reportedly it was only when the MAX was really light and loaded close to the AFT COG limit) it should not be materially less safe without MCAS.

However I would be very surprised if it does have certain issues that make a stall unrecoverable.

Yes the Nacelle's generate more lift - but once lift is lost the heavier more forward placement of the engines should make stall recovery easier as it would pull the nose down.

Flying through air is not like driving on Asphalt - on calm days it is but on Crappy days you really can't go by feel.

So Pilots are taught to never rely upon the feel and to rely upon their instruments. That is especially true in Instrument conditions where there is no outside visibility.

The human mind will totally trick you into thinking the plane is doing one thing when it is doing something completely opposite.

I don't have an example from flying but I have a great personal story from Snowmobiling.

One time I was out on my lake in Blizzard conditions. I had to cross an open part of the lake (no islands but lots of ice so I wasn't worried about about going swimming) that was only about 2km across and I had done it 1,000 times. So I started off and held the handlebars what I thought was straight - it should have only taken 2-3 minutes to cross - 2-3 minutes later I ended up exactly where I started - I did a big loop.

I then did it again and ignored my instincts and held the handlebar to what I though was the left. I crossed successfully and ended up exactly where I wanted to on the opposite shore in a straight line from where I started.

Finally on FBW - it depends - Pilots have managed to stall those as well - however based on some of the incidents it seems like back driven FBW controls where one Pilot can tell what the other is doing would be a really good regulation to implement for new designs. I think the C-Series has this - I'm not sure about other FBW designs.

This is a great article explaining the advantages and disadvantages of various control systems https://thepointsguy.com/news/is-boeing ... ine-pilot/
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 3:31 pm

XRAYretired wrote:
morrisond wrote:
Oykie wrote:
I have read the Canadian authorities e-mail and the tweet from Jon Ostrower. I am very curious as to what kind of new issues are constantly appearing regarding MCAS on the 737MAX. Is the system not well known and described at this point? I know reading someone's e-mail out of context can be a bit misleading. Is what they are suggesting even possible?


I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

I've been saying for months the MAX could be a lot safer overall without MCAS.

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.

Mis-interpretation of described MCAS V2.0 function, to identify a non-catastrophic condition, leading to usual off topic global training standards guff.


So what is your interpretation? I said I was guessing.

If they remove MCAS do you not think more stall training would be a good idea? If not why do you think the FAA is requiring it now?

Probably because most of the other fatals in the past 10 years were due to stalls.

Remove MCAS from the MAX (if it can be recovered safely from a stall without it) - and implement new Global Standards for stall training.

Overall safety in the system improves.
 
Ertro
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 3:43 pm

morrisond wrote:
So what is your interpretation? I said I was guessing.


There clearly is something that we do not know. The letter says new issues keep popping up. So by definition any old issue that a.net has been talking about for ages is not the correct guess. This might be a good moment to take a pause to acknowledge that there is something going on that we do not know and wait for some new information to come to maybe bring some light into what are the new issues that nobody here knows what they are. Instead of bringing up some old stuff that we can be sure is WRONG.
 
DenverTed
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 3:59 pm

I think they could fix MCAS, but once the aircraft was grounded, there was scope creep to anything that is wrong with the 737 is fair game. So the bit flip and dual computer architecture got thrown in. Now there are so many cooks in the stew, I don't see how new issues and concerns will ever cease, and the prospect of agreement is going to be a long one. If the computer systems are so buggy, it's amazing that STS and mach trim function reliably on the NG.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 4:30 pm

Ertro wrote:
morrisond wrote:
So what is your interpretation? I said I was guessing.


There clearly is something that we do not know. The letter says new issues keep popping up. So by definition any old issue that a.net has been talking about for ages is not the correct guess. This might be a good moment to take a pause to acknowledge that there is something going on that we do not know and wait for some new information to come to maybe bring some light into what are the new issues that nobody here knows what they are. Instead of bringing up some old stuff that we can be sure is WRONG.


What? That it might be possible that the MAX could be deemed acceptable without MCAS by granting an exemption to the stick force rule?

I might be wrong - but the Transport Canada letter suggests I might be right. Neither I nor you can be sure of anything.
 
flipdewaf
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 4:41 pm

morrisond wrote:
flipdewaf wrote:
morrisond wrote:
I'm guessing it's because under 12.1 because MCAS would only fire once - if the Pilot get's the AOA high enough again close to a stall the controls will get a little light.

And if that is okay and allowed to stand why is it even needed in the first place?

That is pretty weird, it’s either needed or not right? I had heard that there was the potential to allow one MCAS application per high AoA event.

morrisond wrote:

I've been saying for months the MAX could be a lot safer overall without MCAS.

That’s totally illogical from a safety perspective though. If the solution to the handling issue is more dangerous than the handling characteristic that doesn’t mean we should accept the handling characteristic, it means you need a different solution.

If my solution so stop someone burning themselves on a hot pipe at work is to have a pit bull that rips your arm off of you get too close does not mean that we should remove the pit bull and just accept that people can burn themselves.

morrisond wrote:

Maybe just some more recurrent stall training is needed (and it is now in the US I believe as their sims are required to be able to replicate stalls).

FBW hasn't been the magic bullet to prevent stalls that develop into fatal crashes - this would be a Worldwide Global Pilot Training Issue.


There are no magic bullets, there are reasonable improvements hat add to the safety of the system, FBW being one of them.
morrisond wrote:

It's one of the most important aspects of Primary training and should be taught incessantly throughout a Pilots career.

Controls get light - it happens especially in turbulence - as a Pilot you can't just rely on the feel of the controls - you have to continuously monitor your flight path on your instruments or by outside visual reference ( if available) constantly as in every few seconds - like under 3.


I wasn’t aware of the controls going light in turbulence. The reason why the control ‘feel’ is so important is because the human body is much better at force based proprioception than displacement proprioception.

Sorry Morrisond I feel I’m picking on you, I’m not, you just being up interesting points that I can look up and answer to on my phone.

Fred


Sent from my iPhone using Tapatalk


No worries at all.

The big question is does the MAX have handling issues that aren't that benign.
we know that the handling is not benign enough to pass the regulatory hurdles, if we can ignore this regulation because it’s difficult to pass then that’s a whole different can of worms being opened!

morrisond”]

If it does then the best solution is probably to put a bullet into it. [/quote]

I disagree, implementation of MCAS in a more robust way is ok.

[quote="morrisond wrote:
If not and the controls just get lighter than allowed (and reportedly it was only when the MAX was really light and loaded close to the AFT COG limit) it should not be materially less safe without MCAS.

My brain doesn’t appear to functioning today but as far as I can make out the phenomenon that MCAS is trying to rectify is that’s the engines produce a nonlinear shift of the centre of lift forward that the the normal shift of the centre lift rearwards due to the effect of the elevators. I can’t grok how the CoG alters this purely aerodynamic phenomenon.

morrisond wrote:


However I would be very surprised if it does have certain issues that make a stall unrecoverable.

Likewise, that would be very extreme.

morrisond wrote:


Yes the Nacelle's generate more lift - but once lift is lost the heavier more forward placement of the engines should make stall recovery easier as it would pull the nose down.

The aircraft is still stable, I don’t think the MAX has a particularly forward CoG due to the engines. As far as I know there was some movement of internal hardware to balance the engine move.

morrisond wrote:

Flying through air is not like driving on Asphalt - on calm days it is but on Crappy days you really can't go by feel.

You can (and do)go on force based proprioception for controls.

morrisond wrote:

So Pilots are taught to never rely upon the feel and to rely upon their instruments. That is especially true in Instrument conditions where there is no outside visibility.

I think there is some confusion about the forces that are being talked about. You are right in that one shouldn’t rely on sensing acceleration forces for determining aircraft position/loading/ direction of gravity etc. But control forces absolutely are used in conjunction with feedback from outside reference and or instruments. The pilot references a particular or multiple instruments and uses an increase or decrease in force on relevant controls to reduce the error to the target position on the instruments. This is a broadly subconscious process which is why it’s so important to understand from a control perspective.

morrisond wrote:


The human mind will totally trick you into thinking the plane is doing one thing when it is doing something completely opposite.

I don't have an example from flying but I have a great personal story from Snowmobiling.

One time I was out on my lake in Blizzard conditions. I had to cross an open part of the lake (no islands but lots of ice so I wasn't worried about about going swimming) that was only about 2km across and I had done it 1,000 times. So I started off and held the handlebars what I thought was straight - it should have only taken 2-3 minutes to cross - 2-3 minutes later I ended up exactly where I started - I did a big loop.

I then did it again and ignored my instincts and held the handlebar to what I though was the left. I crossed successfully and ended up exactly where I wanted to on the opposite shore in a straight line from where I started.

During my flying training (just a lowly PPL here) my instructor demonstrated this to me by flying in to a cloud and asked me to just look out of the window, I noticed nothing through my senses until we shot out of the bottom of the cloud, I’d say we were vertical but it wasn’t that extreme.

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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 4:42 pm

morrisond wrote:
Remove MCAS from the MAX (if it can be recovered safely from a stall without it) - and implement new Global Standards for stall training.

Overall safety in the system improves.

I believe that is what Mr. Marko is suggesting: address Flaps 0 non compliance by an adjustment to the FCC (maybe an earlier stick shaker?) and Windup Turn Flaps 0 non compliance by proving safe handling characteristics i.e. do enough testing to be convinced that the plane is safe despite not meeting the letter of the law.

Then you can tell the public that MCAS is removed and the aircraft is proven safe both by current testing and all the NG flight data.

Basically it's a gamble that the odds of MCAS creating future safety problems is greater than the odds of a pilot entering a flaps 0 wind up turn and over-controlling themselves into a spin/stall due to the lighter than legally specified stick forces.

There's no way of knowing what would be the better path. One thing is for sure is that there will be a lot of second guessing regardless of which path is followed.

It seems pretty clear that Mr. Marko is convinced the safer thing to do is drop MCAS, if for no other reason than he could sleep at night more soundly with it removed.

I'm not sure that will be the final outcome, though.
Last edited by Revelation on Sat Nov 23, 2019 4:56 pm, edited 2 times in total.
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 4:52 pm

How about auto deploying some flaps in case of a stall approaching? We're talking about slow flight aren't we?
 
CriticalPoint
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 4:58 pm

Noshow wrote:
How about auto deploying some flaps in case of a stall approaching? We're talking about slow flight aren't we?


This already exists on the 777 it’s called auto slats and on the 787 it’s called auto gap. It moves the slats to the full position but ONLY when the slats are in the mid position. So not when Flaps and Slats are up.

It’s been to long since Iv flown a 737 I can’t remember if they have this, but the technology is there.
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 5:05 pm

morrisond wrote:
The big question is does the MAX have handling issues that aren't that benign. If it does then the best solution is probably to put a bullet into it. If not and the controls just get lighter than allowed (and reportedly it was only when the MAX was really light and loaded close to the AFT COG limit) it should not be materially less safe without MCAS.

You have stated this often, about aft COG and light loading, but you forget that I have already disproven that. Aft COG and light loading are the test conditions which the regulations specify. It was a journalist who incorrectly interpreted this as meaning that this is the only condition in which the MAX fails to pass the test.

In fact, a pilot conducting an engineering cab simulator flight, mentions that the test was conducted at midrange COG. He describes the stall characteristics, including his detection of stick lightening. Interestingly, he does describe the characteristics in a way that I would interpret as benign. However, such characteristics are expected to be more benign at midrange COG than at aft COG. So, we only really know one thing from this: the MAX fails to meet the regulations, even at midrange COG. And, we still don't know the stall characteristics of the MAX at aft COG and light loading.

I kindly request you stop saying that MCAS is only needed at aft COG and light loading. Continuing to do so is spreading misinformation.
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 5:38 pm

checklist350 wrote:
ACATROYAL wrote:
Being Canadian... I love our response from the Canadian authorities investigating the MCAS on the Max as retweeted by Jon Ostrower form the Air Current Simply remove it entirely from the plane! Two things with this statement.

https://twitter.com/jonostrower
"UPDATED: Transport Canada safety official urges removal of MCAS from 737 Max
Transport Canada safety official urges removal of MCAS from 737 Max
A Transport Canada safety official in an email to his counterparts in the United States, Europe and Brazil outlined his misgivings about the revised
[/i]"[/i]

1. After all this time MCAS is still raising red flags!!
2, Can it actually be removed and make the plane safe...or safer to fly?


The most significant takeaway for me is that the "final decisions on acceptance will not be technically based."

Note he did not say "may". This does not engender trust in the recertification process.


You should quote the whole sentence, and a bit more for context. Otherwise, you are misrepresenting Mr. Marko's words.

Jim Marko: "Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based. This leaves me with a level of uneasiness that I cannot sit idly by and watch it pass by."

He is not definitively saying that the grounding will not be technically based. Rather, he says that he is worried about that happening. He is calling out to his fellow regulators to prevent the decision from being made on a non-technical basis. I presume his fear is the the decision will be forced for political reasons instead.
 
checklist350
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:02 pm

morrisond wrote:

The big question is does the MAX have handling issues that aren't that benign. If it does then the best solution is probably to put a bullet into it.


Never expected to be more benign to the 737 MAX compared to morrisond, LOL!

Non-MCAS stall characteristics are central to the necessary solution, I think we have finally come to the point where everybody agrees on that. Except Boeing so it seems, which doesn't bode well...

I believe a third sensor (and possibly sim training) should be enough to make MCAS reliable enough for a catastrophic failure. An expensive redesign for Boeing but manageable.

If it really is only about stick-feel sim training for non-MCAS behaviour should be mandatory, as you cannot learn that from an iPad. Even morrisond should agree to that..?
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:16 pm

aerolimani wrote:

You should quote the whole sentence, and a bit more for context. Otherwise, you are misrepresenting Mr. Marko's words.

Jim Marko: "Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based. This leaves me with a level of uneasiness that I cannot sit idly by and watch it pass by."

He is not definitively saying that the grounding will not be technically based. Rather, he says that he is worried about that happening. He is calling out to his fellow regulators to prevent the decision from being made on a non-technical basis. I presume his fear is the the decision will be forced for political reasons instead.


Adding that context doesn't change anything to what he said. He's expecting the acceptance to be political, not just fearing, otherwise he'd have said "may" not be technically based.
Last edited by checklist350 on Sat Nov 23, 2019 6:22 pm, edited 3 times in total.
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:32 pm

checklist350 wrote:
aerolimani wrote:

You should quote the whole sentence, and a bit more for context. Otherwise, you are misrepresenting Mr. Marko's words.

Jim Marko: "Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based. This leaves me with a level of uneasiness that I cannot sit idly by and watch it pass by."

He is not definitively saying that the grounding will not be technically based. Rather, he says that he is worried about that happening. He is calling out to his fellow regulators to prevent the decision from being made on a non-technical basis. I presume his fear is the the decision will be forced for political reasons instead.


Adding that context doesn't change anything to what he said. He's expecting the acceptance to be political, not just fearing, otherwise he'd have said "may" not be technically based.

I am feeling that ≠ I am certain that

It's his opinion, and he's stating it as such. Context is important.
 
checklist350
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:33 pm

aerolimani wrote:
checklist350 wrote:
aerolimani wrote:

You should quote the whole sentence, and a bit more for context. Otherwise, you are misrepresenting Mr. Marko's words.


He is not definitively saying that the grounding will not be technically based. Rather, he says that he is worried about that happening. He is calling out to his fellow regulators to prevent the decision from being made on a non-technical basis. I presume his fear is the the decision will be forced for political reasons instead.


Adding that context doesn't change anything to what he said. He's expecting the acceptance to be political, not just fearing, otherwise he'd have said "may" not be technically based.

I am feeling that ≠ I am certain that

It's his opinion, and he's stating it as such. Context is important.


This argument is silly, I suggest you look up the difference between will and may. And even if it was sloppy word usage, the fact he's fearing a political decisions is quite worrisome in itself as everything we've heard until now was that no stone would be left unturned in the flight control redesign regulatory approval, with quite strong (political?) language by both FAA & EASA.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:41 pm

CriticalPoint wrote:
Noshow wrote:
How about auto deploying some flaps in case of a stall approaching? We're talking about slow flight aren't we?


This already exists on the 777 it’s called auto slats and on the 787 it’s called auto gap. It moves the slats to the full position but ONLY when the slats are in the mid position. So not when Flaps and Slats are up.

It’s been to long since Iv flown a 737 I can’t remember if they have this, but the technology is there.

MCAS started as a high speed, high load scenario. Would flaps and actuators even be strong enough mechanically to withstand deployment at full speed?
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 6:52 pm

checklist350 wrote:
aerolimani wrote:
checklist350 wrote:

Adding that context doesn't change anything to what he said. He's expecting the acceptance to be political, not just fearing, otherwise he'd have said "may" not be technically based.

I am feeling that ≠ I am certain that

It's his opinion, and he's stating it as such. Context is important.


This argument is silly, I suggest you look up the difference between will and may. And even if it was sloppy word usage, the fact he's fearing a political decisions is quite worrisome in itself as everything we've heard until now was that no stone would be left unturned in the flight control redesign regulatory approval, with quite strong (political?) language by both FAA & EASA.

Fearing. Yes, exactly.

And no, this discussion is not silly. Proper context is extremely important when quoting.

Speaking of context, let's not forget that this is an inter-organizational email, and was almost certainly never intended for public scrutiny. In organizations, both private and public sector, there's frequently a difference between the public statements (like press releases) and the internal and inter-organizational communications.

Indeed, it is worrisome, though. I can't say that I'm completely surprised, however it is still disheartening to read a Transport Canada employee writing this to his compatriots at the FAA, the EASA, and the ANAC (Brazil). I would still hope that all four agencies are more immune to political pressure than Mr. Marko feels.
 
checklist350
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 7:02 pm

aerolimani wrote:
checklist350 wrote:
aerolimani wrote:
I am feeling that ≠ I am certain that

It's his opinion, and he's stating it as such. Context is important.


This argument is silly, I suggest you look up the difference between will and may. And even if it was sloppy word usage, the fact he's fearing a political decisions is quite worrisome in itself as everything we've heard until now was that no stone would be left unturned in the flight control redesign regulatory approval, with quite strong (political?) language by both FAA & EASA.

Fearing. Yes, exactly.

And no, this discussion is not silly. Proper context is extremely important when quoting.

Speaking of context, let's not forget that this is an inter-organizational email, and was almost certainly never intended for public scrutiny. In organizations, both private and public sector, there's frequently a difference between the public statements (like press releases) and the internal and inter-organizational communications.

Indeed, it is worrisome, though. I can't say that I'm completely surprised, however it is still disheartening to read a Transport Canada employee writing this to his compatriots at the FAA, the EASA, and the ANAC (Brazil). I would still hope that all four agencies are more immune to political pressure than Mr. Marko feels.


Again, the context doesn't change his words, stop stating your own interpretation to what he said as fact. 'Feeling' (versus thinking) isnt the only operative word when it comes to expecting or fearing but also 'will' (versus may). Now stop the silly nitpicking as both interpretations don't change anything to the severity of his message,
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 10:44 pm

DenverTed wrote:
I think they could fix MCAS, but once the aircraft was grounded, there was scope creep to anything that is wrong with the 737 is fair game.

The fear of scope creep was top of mind at Boeing when the various investigations started. That's why Boeing publicly stated what they thought the terms of reference should be to improve MCAS. Boeing management must have known about other MAX (and NG) shortcomings previously raised by staff, customers and airworthiness authorities.

Boeing has lobbied the various investigating authorities to allow these other issues to be resolved completely separately by way of AD, documentation, operational changes, or no action. As more have come to light, presumably some pre-dating MAX but still not resolved, trust and confidence becomes top of mind.
 
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 11:07 pm

Is there any other airliner (bigger than stealth fighter jets) with system augmented maneuverability? I know BDS(and others) mastered the art of flying inherently unstable aerodynamic platforms to achieve stealth characteristics.

KC-46 is still new, and it is based on 767 different computer architecture. What about other mid-air refueling tankers.
Is MAX the first one?

Hypothetically, if BCA comes up with an unaugmented design, can it rework all the frames it already built.
All posts are just opinions.
 
Dupli
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sat Nov 23, 2019 11:34 pm

With or without MCAS, the max now looks to be a less safe design than the NG. And is expected to become Boeing's biggest seller. How is this acceptable? Society really has it's priorities wrong.
 
DenverTed
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 12:12 am

Is MCAS more demanding on the computers than STS, mach trim, or yaw dampers? Seems like it would all be about the same.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 12:25 am

DenverTed wrote:
Is MCAS more demanding on the computers than STS, mach trim, or yaw dampers? Seems like it would all be about the same.

I suspect that most of those functions operate based on the current state of aircraft, maybe on change compared to the previous state.
MCAS was in the same boat initially, but now it needs to know quite a bit of history - and that feature, however trivial that is by modern standards, is the last straw.
 
beechnut
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 12:57 am

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
 
mjoelnir
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 1:40 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


Perhaps you start with the NG does not meet certification standards. Full of exemptions. The excuse is always, but the accident record, it's proven safe.

16 G floor. NG exempt. I assume that adds weight and complying to it would reduce one advantage the NG has over the A320. Here I do not understand, that this exemption moves from model to model.

EICAS.. The NG had an exemption for the man machine interface. Continues with the MAX.

That is for starters. What would it matter if the MAX gets an exemption from the stick force near stall, if it makes it a safer frame and the coffin maker program gets canceled.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 1:47 am

dtw2hyd wrote:
Is there any other airliner (bigger than stealth fighter jets) with system augmented maneuverability?

Any FBW aircraft by definition expose some sort of augmented maneuverability. This does not imply that FBW aircraft have maneuverability issue without augmentation, but augmented maneuverability is an implicit feature of a FBW system, in addition to flight envelop protection. Airbus certainly used that advantage to update the A320 to the A320neo.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
beechnut
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 1:55 am

mjoelnir wrote:

Perhaps you start with the NG does not meet certification standards. Full of exemptions. The excuse is always, but the accident record, it's proven safe.

16 G floor. NG exempt. I assume that adds weight and complying to it would reduce one advantage the NG has over the A320. Here I do not understand, that this exemption moves from model to model.

EICAS.. The NG had an exemption for the man machine interface. Continues with the MAX.

That is for starters. What would it matter if the MAX gets an exemption from the stick force near stall, if it makes it a safer frame and the coffin maker program gets canceled.


Yes I get that the NG has exemptions, but perhaps the MAX is one exemption too far. Stick forces at stall? I'm wary about exemptions that require counter-intuitive flying skills ingrained in the days we hopped around the patch in a C-150 and for thousands of hours later. Yeah I supposed it could be un-learned, but...

Beech
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 2:22 am

DenverTed wrote:
Is MCAS more demanding on the computers than STS, mach trim, or yaw dampers? Seems like it would all be about the same.

Important point. Instead of being inherently stable in all flight envelopes, it's kept stable by relying on sensors and control surfaces. Some may say that's what the auto pilot does on a regular basis, but theirs a difference between the amount of input required to maintain stability.
Boeing has to switch off mcas and take actual trials in all manual modes of the flight, not simulations. Under no circumstances should a plane return to service which reduces the safety standards, modern civilian planes have reached after decades of innovation.
It has to be repeatedly demonstrated that the actual scenario the 2 fatal flights faced, can now be successfully overcome, without needing exceptional skill levels. I mean should be recoverable by relying solely on the manual wheel.
Also how will the plane with varying fuel , passenger and luggage loads, behave when in the same situation ?
 
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BoeingVista
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 9:37 am

maint123 wrote:
DenverTed wrote:
Is MCAS more demanding on the computers than STS, mach trim, or yaw dampers? Seems like it would all be about the same.

Important point. Instead of being inherently stable in all flight envelopes, it's kept stable by relying on sensors and control surfaces. Some may say that's what the auto pilot does on a regular basis, but theirs a difference between the amount of input required to maintain stability.
Boeing has to switch off mcas and take actual trials in all manual modes of the flight, not simulations. Under no circumstances should a plane return to service which reduces the safety standards, modern civilian planes have reached after decades of innovation.
It has to be repeatedly demonstrated that the actual scenario the 2 fatal flights faced, can now be successfully overcome, without needing exceptional skill levels. I mean should be recoverable by relying solely on the manual wheel.
Also how will the plane with varying fuel , passenger and luggage loads, behave when in the same situation ?


And that should be the red flag for everybody here, regulators have been asking Boeing to switch the toys off and do demonstration flights unaugmented for 6+ months and Boeing refuse to do this. Why?
BV
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 9:57 am

Because they know how it behaves in raw flight.
Just look at the powers they gave to MCAS 1.0.
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 10:14 am

How about the "Leanliner"?
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Sun Nov 24, 2019 4:01 pm

morrisond wrote:
The big question is does the MAX have handling issues that aren't that benign. If it does then the best solution is probably to put a bullet into it. If not and the controls just get lighter than allowed (and reportedly it was only when the MAX was really light and loaded close to the AFT COG limit) it should not be materially less safe without MCAS.


And this, really, is what many have been asking themselves from day one of this drama. And that we were repeatedly being bombarded by some (incluidng yourself) that it is just the controls getting light, and/or to make it feel like an NG.

This really is the billion dollar question.

The JATR report also goes into this very subject, since they recognized that the unaugmented stall characteristiocs have not been documented nor demonstrated as part of the original MAX certification effort:

JATR Final Report wrote:
Finding F3.4-A: The acceptability of the natural stalling characteristics of the aircraft should form the basis for the design and certification of augmentation functions such as EFS and STS (including MCAS) that are used in support of meeting 14 CFR part 25, subpart B requirements.

Finding F3.5-A: The nose-down pitch identified during Boeing flight tests for stall appears to the JATR team to be the product of system augmentation with flaps and gear up, and is likely due to stabilizer motion from the MCAS function.




morrisond wrote:
However I would be very surprised if it does have certain issues that make a stall unrecoverable.

I guess the question is not so much whether such stall is (un)recoverable, rather how much altitude loss is associated with the recovery. The level of how far a stall is growing has a big effect on altitude loss, and whether that initial stall is symmetrical. I wonder if Mr Marko has access to the bare stall characteristic data . . .
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