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maint123
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 4:12 pm

So did Max take a test flight with mcas switched off or that's off the table?
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 5:17 pm

maint123 wrote:
So did Max take a test flight with mcas switched off or that's off the table?


the devil will relish a meal of flies before that happens. ( If the manufacturer gets his mind.)
Murphy is an optimist
 
hivue
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 6:57 pm

par13del wrote:
So the wiring has to be changed because it is not safe?
How would they allow the NG's to continue to fly without a refit, as far as I have seen.


The NG does not have to meet this certification requirement because the requirement did not exist when it was certified.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
XRAYretired
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 8:25 pm

hivue wrote:
par13del wrote:
So the wiring has to be changed because it is not safe?
How would they allow the NG's to continue to fly without a refit, as far as I have seen.


The NG does not have to meet this certification requirement because the requirement did not exist when it was certified.

Runaway Stabilizer has been deemed potentially Catastrophic. If, (we don't know for sure), hot short within the wiring bundles can result in such, then NG will have to be considered in the same way as MAX and decision reached regarding the perceived need for modification or mitigation for no action.

It is not clear to me if the wire separation requirement was or was not in place for NG design/certification. Either way makes no significant difference to the decision required.

Ray
 
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flyingphil
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 9:12 pm

Scotron12 wrote:
A question: IAG have an LOI for 200 B737MAX from June 2019 with EIS of 2022. The models chosen are the MAX 8 and MAX 10.

With the grounding still ongoing and RTS not expected until this summer, how realistic is that date? And what mix do Boeing start producing between the 3 models?

I guess ramp up will be to clear the MAX8 back log first.


Good question.. I got the impression that the LOI was more of a warning shot to Airbus to not take IAG for granted.. Willie Walsh was grumbling about late deliveries from Airbus and the price of the A380.. with him heading for retirement will it ever be converted to a firm order?
Only 20 were for British Airways to replace the second hand A320’s based at Gatwick. . the 737 is not much use at Heathrow as it cant take luggage in containers (I believe).
The 737 MAX10 looks like a tailstrike waiting to happen.. I think the first prototype has only recently just flown.
EIS of 2022 looks a bit optimistic.
 
bspc
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Re: Boeing 737MAX Grounding News and Reference Thread 2020

Sun Feb 16, 2020 10:44 pm

Is there a site where one can see the total number of test Flight hours for the 737 MAX test Aircraft in relation to its Grounding? Similar to what the AIB Family Flights sit oes to Airbus Aircraft?
 
hivue
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Sun Feb 16, 2020 11:51 pm

XRAYretired wrote:
It is not clear to me if the wire separation requirement was or was not in place for NG design/certification.


https://www.seattletimes.com/business/b ... ng-missed/

Boeing’s argument rests on the long service history of the earlier model 737, which has the same wiring. That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
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seahawk
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:11 am

flyingphil wrote:
Scotron12 wrote:
A question: IAG have an LOI for 200 B737MAX from June 2019 with EIS of 2022. The models chosen are the MAX 8 and MAX 10.

With the grounding still ongoing and RTS not expected until this summer, how realistic is that date? And what mix do Boeing start producing between the 3 models?

I guess ramp up will be to clear the MAX8 back log first.


Good question.. I got the impression that the LOI was more of a warning shot to Airbus to not take IAG for granted.. Willie Walsh was grumbling about late deliveries from Airbus and the price of the A380.. with him heading for retirement will it ever be converted to a firm order?
Only 20 were for British Airways to replace the second hand A320’s based at Gatwick. . the 737 is not much use at Heathrow as it cant take luggage in containers (I believe).
The 737 MAX10 looks like a tailstrike waiting to happen.. I think the first prototype has only recently just flown.
EIS of 2022 looks a bit optimistic.


IAG just recently confirmed that they plan on taking the MAX and have full confidence in the performance of the plane. There will be many large orders placed in the coming weeks.
 
oschkosch
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:39 am

seahawk wrote:
There will be many large orders placed in the coming weeks.


Sources please? Or is it just your own opinion/hope?
:stirthepot: :airplane: "This airplane is designed by clowns, who in turn are supervised by monkeys" :airplane: :stirthepot:
 
seb76
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 7:47 am

hivue wrote:
par13del wrote:
So the wiring has to be changed because it is not safe?
How would they allow the NG's to continue to fly without a refit, as far as I have seen.


The NG does not have to meet this certification requirement because the requirement did not exist when it was certified.


A certification is an important step in the life of an aircraft model, but it's not the end, it does not yet permanently freeze the design: That may only happen when the last plane of the type gets retired !

Potential issues can be identified at any time during his life and soon or late, AD's will require small changes to the already certified design. Complying with the regulations is a must, but that alone won't guarantee your design is considered as perfectly safe as things wear out or when new risks are identified.
Even if you own a very simple GA plane certified in the 60's, you may have had to recently replace a perfectly working parts by a different type as some risks were re-evaluated..
Not saying that it will be necessary to modify the NG's in this case, the regulators and manufacturer will tell when they reach to a conclusion, but never say never...
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 9:20 am

seb76 wrote:
A certification is an important step in the life of an aircraft model, but it's not the end, it does not yet permanently freeze the design: That may only happen when the last plane of the type gets retired !


With airplanes having a limited life in use it could be deemed acceptable that certain requirements are not met.
( Just like automobile models once in use are not required to be moved forward to newer emission standards.
note: at least in the EU newer standards apply to all production. Either move it forward or discontinue the type!
new requirements apply by production date and not by certification date.)

Now creating a revamped type after 15..20 years while still keeping up the non-conformance to current regulations
extends this over a much longer timeframe ( 20..25 years longer will airplanes fly that are certified to ancient standards.)

In a range of aspects737 today fly with a 50+ year delta to current certification requirements.
And that lack is not in "just minor details".
Murphy is an optimist
 
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seahawk
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 10:12 am

oschkosch wrote:
seahawk wrote:
There will be many large orders placed in the coming weeks.


Sources please? Or is it just your own opinion/hope?


Mostly mathematics.
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 10:33 am

seahawk wrote:
oschkosch wrote:
Sources please? Or is it just your own opinion/hope?


Mostly mathematics.


Tailback?

If there are so many in the chute I'd have expected more rumors. ( Beyond that LOI from IAG?)
Boeing would have been happy to bolster their standing re MAX with a smidgen of rumors, wouldn't they?

On the other hand beyond new type orders ( XLR ) I don't see a major rise in orders on the Airbus side?
Then with the backlogs as they stand any new interest can sit pretty and wait for the outcome.
Order now, order later You'll not get your frames before the second half of the decade.
Murphy is an optimist
 
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seahawk
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 10:39 am

Which means you can not actually wait, once the MAX is certified again. There is no point to announce the order now and the media reaction to the LoI by IAG showed this, but airlines will still need to order their NG/CEO replacements for the second half of the decade.
 
TTailedTiger
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 10:53 am

WIederling wrote:
maint123 wrote:
So did Max take a test flight with mcas switched off or that's off the table?


the devil will relish a meal of flies before that happens. ( If the manufacturer gets his mind.)


Just what do you think would happen if it's turned off? A big explosion? MCAS is not a stability system. The plane operates just fine without it. It's an aid in stall recovery and nothing more.
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 11:10 am

TTailedTiger wrote:
WIederling wrote:
maint123 wrote:
So did Max take a test flight with mcas switched off or that's off the table?


the devil will relish a meal of flies before that happens. ( If the manufacturer gets his mind.)


Just what do you think would happen if it's turned off? A big explosion? MCAS is not a stability system. The plane operates just fine without it. It's an aid in stall recovery and nothing more.


Make an absurd intepretation and deride from there.:-) Schopenhauer #nn

EASA and others? want to test a MAX with "only MCAS disabled".
This requires that Boeing prepare a MAX appropriately.

Going by things visible in public : Boeing apparently is bending over backwards to hinder/delay/avoid this test.

Whatever MCAS could be, it is more than
"MCAS is not a stability system"
( current Boeing Pravda on what MCAS is or is not.)

Two motivators thinkable ( either, or or both ):
* Airframe behavior currently amended/wrapped by MCAS is a lot less harmless
than any mealy mouthed PR would admit.
* Boeing will never give in to any demand from unwashed EASA.
That would be (perceived) a dam break for Boeing standing in crotch deep water ever after.
Murphy is an optimist
 
Ertro
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 12:00 pm

WIederling wrote:
Two motivators thinkable ( either, or or both ):
* Airframe behavior currently amended/wrapped by MCAS is a lot less harmless
than any mealy mouthed PR would admit.
* Boeing will never give in to any demand from unwashed EASA.
That would be (perceived) a dam break for Boeing standing in crotch deep water ever after.


If the problem is that Boeing does not want to give in to any demand from EASA that itself is so ludicrous thing like a 5 year old tries be a kindergarten bully that I refuse to believe it. However there are things that make some people believe that as a possibility that I think is it silly that Boeing allows this kind of view to develop at all.

There is several ways how Boeing could solve this dilemma even not giving in to any demand to EASA.

Invite a bunch of nobodys to test fly the plane first. Like representatives from big 3 US airline pilots unions. Let them try the plane without MCAS and videotape how it approaches stall. Invite a bunch of journalists from several aviation magazines that can nominate their favourite qualified test pilot to do same thing. So on and so on. Imagine all the positive press that says how they have seen with their own eyes the plane to behave fantastically and it just the evil FAA/EASA who don't want the plane in the air.

After that let EASA people test fly the plane. Now it cannot any more be seen like giving a finger to the evil EASA since it happens after a bunch of nobodys have done it first.

Of course this plan requires that the plane is actually behaving even close to acceptable. In this case I cannot imagine a reason why Boeing has not done this already a long time ago. Why does Boeing let the idea get stronger and stronger for months that there is something hidden in there.
 
Aviator34ID
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 1:28 pm

"Why does Boeing let the idea get stronger and stronger for months that there is something hidden in there."

Possibly because the FAA made it very clear that they wanted Boeing to shut up until the FAA has spoken.
 
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scbriml
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 1:40 pm

Aviator34ID wrote:
"Why does Boeing let the idea get stronger and stronger for months that there is something hidden in there."

Possibly because the FAA made it very clear that they wanted Boeing to shut up until the FAA has spoken.


IIRC, the only thing the FAA asked Boeing to “shut up” about was repeatedly issuing unachievable RTS dates. What else was there?
Time flies like an arrow. Fruit flies like a banana!
There are 10 types of people in the World - those that understand binary and those that don't.
 
upright
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 2:57 pm

Aviator34ID wrote:
"Why does Boeing let the idea get stronger and stronger for months that there is something hidden in there."

Of course there are numerous political forces working in the background, who are upset with Boeing management.
Unfortunately, those and their families would also have to sit on a MAX and have no escape to government planes or Learjets at their disposal.
And lots other reasons.........
 
upright
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 3:15 pm

why Boeing and FAA together announced such a wire problem alreday now, if not tended to solve it right away ? Instead, they heavy arguing about it. They could have just shut up for a while, as there is lots of time until summer. What's embarrassing confusing to worry next ?
 
maint123
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 3:36 pm

TTailedTiger wrote:
WIederling wrote:
maint123 wrote:
So did Max take a test flight with mcas switched off or that's off the table?


the devil will relish a meal of flies before that happens. ( If the manufacturer gets his mind.)


Just what do you think would happen if it's turned off? A big explosion? MCAS is not a stability system. The plane operates just fine without it. It's an aid in stall recovery and nothing more.

As per my understanding, mcas was introduced to mitigate the effort required by a pilot to avoid stall , when AoA was detected to be higher than a threshold.
Why trial in absence of mcas is required is that 2 planes crashed when this aoa reading was false and mcas drove the Boeing's into the ground.
The argument of Boeing and its supporters and 3rd world pilot deriders was that , the mcas should have been switched off and the plane flown fully manual .
Its only logical that trials are taken to verify the claims of the Boeing supporters
 
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par13del
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 4:21 pm

WIederling wrote:
* Boeing will never give in to any demand from unwashed EASA.

I thought I saw where it was posted that STS on the NG was the result of some EASA requirements, has EASA changed so much that Boeing no longer wants to work with them?
 
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par13del
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 4:25 pm

maint123 wrote:

The argument of Boeing and its supporters and 3rd world pilot deriders was that , the mcas should have been switched off and the plane flown fully manual .
Its only logical that trials are taken to verify the claims of the Boeing supporters

So we are once again discounting that a MAX with civilians on board was successfully flown with MCAS disabled, not even for a RTB but onward to its destination, and before you talk about the third pilot, for the conclusion that you have drawn, is that relevant?
 
DenverTed
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 4:59 pm

par13del wrote:
maint123 wrote:

The argument of Boeing and its supporters and 3rd world pilot deriders was that , the mcas should have been switched off and the plane flown fully manual .
Its only logical that trials are taken to verify the claims of the Boeing supporters

So we are once again discounting that a MAX with civilians on board was successfully flown with MCAS disabled, not even for a RTB but onward to its destination, and before you talk about the third pilot, for the conclusion that you have drawn, is that relevant?

Is that a real test condition? That the A350 or 787 had to be flown to stall with civilians on board?
 
asdf
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 5:28 pm

hivue wrote:
XRAYretired wrote:
It is not clear to me if the wire separation requirement was or was not in place for NG design/certification.


https://www.seattletimes.com/business/b ... ng-missed/

Boeing’s argument rests on the long service history of the earlier model 737, which has the same wiring. That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.


as far is a know wiring requirements were grandfathered that time
the got it grandfathered from the 737jurassic , didn't they?
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 5:58 pm

par13del wrote:
WIederling wrote:
* Boeing will never give in to any demand from unwashed EASA.

I thought I saw where it was posted that STS on the NG was the result of some EASA requirements, has EASA changed so much that Boeing no longer wants to work with them?


OK, EASA predecessor JAA:
https://www.flightglobal.com/737-700-re ... 63.article

This?
That would indicate curdled s*it flying low. If non US certs had to step on Boeing's toes for the NG already.
Murphy is an optimist
 
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enzo011
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:03 pm

seahawk wrote:
IAG just recently confirmed that they plan on taking the MAX and have full confidence in the performance of the plane. There will be many large orders placed in the coming weeks.


seahawk wrote:
Mostly mathematics.


If it is mathematics that convinces you there are many large order on the horizon, how do you get to that? There are 400 stored frames at Boeing so that is a good amount to help with delivery slots. But what about future slots and how quickly are Boeing able to increase production to meet the current demand in the current order book?

There are 4500 outstanding orders not produced. If Boeing is able to ramp up from day one to 57 a month that is about six and a half years worth of production. But Boeing will not be able to ramp up at that rate from day one of the restart of production, so realistically the time to clear the backlog time is much longer. So mathematically, where do they get the slots in the next few years for these large orders?
 
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seahawk
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:10 pm

It is not what can be produced, but what must be replaced.
 
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PixelFlight
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:12 pm

WIederling wrote:
par13del wrote:
WIederling wrote:
* Boeing will never give in to any demand from unwashed EASA.

I thought I saw where it was posted that STS on the NG was the result of some EASA requirements, has EASA changed so much that Boeing no longer wants to work with them?


OK, EASA predecessor JAA:
https://www.flightglobal.com/737-700-re ... 63.article

This?
That would indicate curdled s*it flying low. If non US certs had to step on Boeing's toes for the NG already.

Very interesting article.
Did I understand correctly that the STS was already containing something that later evolved as the MCAS, to reach the JAA requirement ?
: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:
 
hivue
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:35 pm

asdf wrote:
hivue wrote:
XRAYretired wrote:
It is not clear to me if the wire separation requirement was or was not in place for NG design/certification.


https://www.seattletimes.com/business/b ... ng-missed/

Boeing’s argument rests on the long service history of the earlier model 737, which has the same wiring. That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.


as far is a know wiring requirements were grandfathered that time
the got it grandfathered from the 737jurassic , didn't they?


See the Seattle Times article. The wiring requirements currently of concern were never avoided by grandfathering. For the NG (and Classic, and Jurasic) the requirements didn't exist yet and were far in the future. For the MAX they were missed by Boeing and the FAA.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
WIederling
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:37 pm

PixelFlight wrote:
WIederling wrote:
par13del wrote:
I thought I saw where it was posted that STS on the NG was the result of some EASA requirements, has EASA changed so much that Boeing no longer wants to work with them?


OK, EASA predecessor JAA:
https://www.flightglobal.com/737-700-re ... 63.article

This?
That would indicate curdled s*it flying low. If non US certs had to step on Boeing's toes for the NG already.

Very interesting article.
Did I understand correctly that the STS was already containing something that later evolved as the MCAS, to reach the JAA requirement ?

flightGloba, 2/1998 wrote:
"The JAA insisted on the addition of a system to raise pilot awareness. "We are adding a speed trim system that will demonstrate the stall characteristics more. It will push the nose down as the aircraft goes into a stall," he says. "

Looks like. doesn't it?

IMU:

MCAS uses the actor path established for STS.

It seems to use the same computer hardware. ( i.e. another program block run besides the STS program and other tasks)

speed changes are reasonably slow.
Trimming the tailplane is slow ( in comparison to possible elevator movement speeds).
-> Fits!

AoA changes can be rather fast.
The aggressive (given even more teeth beyond what the FAA even knew about )
behavior of MCAS was due the fact that a slow actor was supposed to
fix/counter a fast change in attitude.
-> Clashes!

Beyond that unsanitized AoA referenced for MCAS action ( additionally boosted ) was the error that made it a sure thing to get exposed.

Most of the back and forth we've seen is to keep all eyes on the last item. never look beyond.
Murphy is an optimist
 
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enzo011
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:41 pm

seahawk wrote:
It is not what can be produced, but what must be replaced.



Agreed, but you can only replace a product you are physically are able to produce, no matter the demand. If Boeing only has open slots for 30 new orders per year (as an example for the next 4 years while they work through the backlog and ramping up) it doesn't matter if the demand is at 600 per year. They will not be able to sell what they cannot produce.
 
LSGL
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:48 pm

Some people are missing the point. Why should EASA ignore the wiring fault? that the issue was not spotted by either Boeing nor the FAA is not a good reason to ignore the problem. That was FAA's mistake, ignoring this after EASA has been informed of this error would place the responsibility on EASA too.
 
oschkosch
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 6:49 pm

enzo011 wrote:
seahawk wrote:
It is not what can be produced, but what must be replaced.



Agreed, but you can only replace a product you are physically are able to produce, no matter the demand. If Boeing only has open slots for 30 new orders per year (as an example for the next 4 years while they work through the backlog and ramping up) it doesn't matter if the demand is at 600 per year. They will not be able to sell what they cannot produce.



:checkmark: I agree Enzo! So basically it is mathematics. But the math clearly shows us that there are no tons of orders on the horizon or hidden in some airline desk drawers. ;)
:stirthepot: :airplane: "This airplane is designed by clowns, who in turn are supervised by monkeys" :airplane: :stirthepot:
 
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par13del
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 7:02 pm

DenverTed wrote:
par13del wrote:
maint123 wrote:

The argument of Boeing and its supporters and 3rd world pilot deriders was that , the mcas should have been switched off and the plane flown fully manual .
Its only logical that trials are taken to verify the claims of the Boeing supporters

So we are once again discounting that a MAX with civilians on board was successfully flown with MCAS disabled, not even for a RTB but onward to its destination, and before you talk about the third pilot, for the conclusion that you have drawn, is that relevant?

Is that a real test condition? That the A350 or 787 had to be flown to stall with civilians on board?

It was a real live situation when the a/c attempted to become a lawn dart with MCAS enabled, the crew disabled MCAS and continued the flight to its destination, it is history versus a real test condition.
 
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par13del
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 7:02 pm

WIederling wrote:
par13del wrote:
WIederling wrote:
* Boeing will never give in to any demand from unwashed EASA.

I thought I saw where it was posted that STS on the NG was the result of some EASA requirements, has EASA changed so much that Boeing no longer wants to work with them?


OK, EASA predecessor JAA:
https://www.flightglobal.com/737-700-re ... 63.article

This?
That would indicate curdled s*it flying low. If non US certs had to step on Boeing's toes for the NG already.

So no problem with the non-washed EASA then....
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 7:30 pm

LSGL wrote:
Some people are missing the point. Why should EASA ignore the wiring fault? that the issue was not spotted by either Boeing nor the FAA is not a good reason to ignore the problem. That was FAA's mistake, ignoring this after EASA has been informed of this error would place the responsibility on EASA too.

There's no actual wiring fault that's ever been demonstrated, there's a failure to comply with a requirement which is based on theoretical considerations.

There's no one asking EASA to ignore any aspect of this issue.

At this point Boeing has made a proposal to FAA, one which may or may not be accepted, to accept the nonconformance with regard to the wiring regulation based on MAX's similarity with NG and NG's history of never seeing an uncommanded stabilizer activation after its millions of flight hours.

It's an interesting gambit, one I presumed had to be approved at the highest levels of the Boeing company, so if it fails they can't blame the previous regime.

I'm kind of surprised Boeing took this path, it suggests that redoing the wiring will cost a lot of time and money.

If FAA accepts then it will be up to EASA to accept or deny.

No need to get our knickers in a knot at this point in time.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
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par13del
Posts: 10325
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 8:30 pm

Revelation wrote:
I'm kind of surprised Boeing took this path, it suggests that redoing the wiring will cost a lot of time and money.

Well they do have some recent experience with up to date cost and man hour requirements, they just did something similar with the tanker.
 
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seahawk
Posts: 9628
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 8:32 pm

enzo011 wrote:
seahawk wrote:
It is not what can be produced, but what must be replaced.



Agreed, but you can only replace a product you are physically are able to produce, no matter the demand. If Boeing only has open slots for 30 new orders per year (as an example for the next 4 years while they work through the backlog and ramping up) it doesn't matter if the demand is at 600 per year. They will not be able to sell what they cannot produce.


The less both big OEMs can produce, the bigger is the need to secure slots early.
 
WillyEckers
Posts: 18
Joined: Mon Dec 23, 2019 6:24 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 8:46 pm

Revelation wrote:
Yet this type of change, going from active/standby pair to active/active pair, is IMO not as challenging as the author makes it out to be. He uses a lot of extraneous verbiage to suggest that it is, but it's been done countless times (I've been a part of teams doing similar things at least three times in my career) and there's a lot of prior art on how to make it work.


I'm new on here but not new to the site or the business... I used to value your contributions but now can only assume that you are not involved in the aerospace industry...

A change of architecture from active/passive to command/monitor or whatever is the correct name for what has been done would (should?) be a massive job. It should start from the top level requirements and get cascaded down to the module specs, each one a formal document with traceability to the higher level. And it's the same for the integration to create the system - the module test plan is based on the module specification and so on to the system validation.

The implied notion that this change in architecture is little more than connecting a couple of wires and then switching it on to see what it does is... let's just say "cute"!

A warning light when there is no fault condition is a non-trivial matter as well...
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 8:55 pm

WillyEckers wrote:
Revelation wrote:
Yet this type of change, going from active/standby pair to active/active pair, is IMO not as challenging as the author makes it out to be. He uses a lot of extraneous verbiage to suggest that it is, but it's been done countless times (I've been a part of teams doing similar things at least three times in my career) and there's a lot of prior art on how to make it work.

A change of architecture from active/passive to command/monitor or whatever is the correct name for what has been done would (should?) be a massive job. It should start from the top level requirements and get cascaded down to the module specs, each one a formal document with traceability to the higher level. And it's the same for the integration to create the system - the module test plan is based on the module specification and so on to the system validation.

The implied notion that this change in architecture is little more than connecting a couple of wires and then switching it on to see what it does is... let's just say "cute"!

A warning light when there is no fault condition is a non-trivial matter as well...

C'mon, what I wrote was that it was not as hard to do as the author suggests and that there's lots of prior art on how to do it, and did not write it was "little more than connecting a couple of wires and then switching it on to see what it does". I think "reduction to absurdity" predates Schopenhauer, no?
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
planecane
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 8:59 pm

If anybody really wanted to do an MCAS off test without support from Boeing, they could do one of two things:

1) Get the aircraft stable and in trim before the maneuver that they want to evaluate. Turn off the electric trim with the cutout switches. Perform the desired maneuver and evaluate the results. You wouldn't be trimming in the middle of a turn anyway.

2) Perform a test flight with all electric trim on. Have the PNF (who would be a test pilot) listen for or watch the trim wheel and any time it starts to move in manual flight, flick the thumb switch very briefly for nose up trim to stop the MCAS cycle.
 
AirBoat
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 9:53 pm

MCAS does not start up only when high AOA is reached, it is continuously active in the background, checking the AOA multiple times per second. (this might be where the bit flip requirement comes from)
Disabling electric trim did not switch off MCAS 1.0.
What is not clear is if MCAS acts on the elevator as well. See post above re needing a fast acting control surface. (Boeing will never release information like this. They are facing legal issues and will say as little as possible about what MCAS actually does.)
Does anyone know if the MCAS 2.0 software is disabled when electric trim is switched off?
 
MartijnNL
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 10:50 pm

TTailedTiger wrote:
MCAS is not a stability system. The plane operates just fine without it. It's an aid in stall recovery and nothing more.

The plane operates just fine without it? Than why did Boeing install MCAS in the first place? The plane sure didn't operate fine with it. Just three more weeks and the Max has been grounded one full year. Boeing better design something new.
 
sgrow787
Posts: 450
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Mon Feb 17, 2020 11:25 pm

AirBoat wrote:
Does anyone know if the MCAS 2.0 software is disabled when electric trim is switched off?

I think the question you meant to ask was:
... if electric trim is disabled when the stab trim cutouts are flipped (which disables MCAS) for MCAS 2.0?

IIRC, the answer to that is no. That is one of the changes between MCAS 1.0 and MCAS 2.0.

EDIT: That seems to solve the manual trim wheel problem (too hard to turn using the manual crank) for the Max pre-crash. Not to imply they shouldn't fix the manual trim wheel. Since electric trim could fail itself (possibly due to a short in that wire bundle).
Just one sensor,
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Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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zkojq
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Tue Feb 18, 2020 12:08 am

planecane wrote:
No matter how "evil and greedy" Boeing is, you can be that they don't need the FAA to ensure they get this fix right. Another MAX crash caused by a design flaw will be the end of Boeing's Commercial Aircraft division.


Really? I'm certain if there was another crash we would see plenty of statements like this:

Revelation wrote:
That's an emotional, knee jerk statement.

Tell people that their favorite trip is going to go up by $20 due to the costs of keeping old planes running longer than planned and they will be ready to tell themselves that they are OK with flying the 737 again.


Sooner787 wrote:
After the anal exam this airframe has been thru, it'll be the safest plane in the skies once it returns to service .

This myth has been debunked multiple times.

Sooner787 wrote:
You'll have better odds of being killed in a car crash to or from the airport .


You'll have better odds of being killed in a car crash to or from the airport when flying LionAir (in fact it's hours per fatality is "more safe" than the MAX), but that doesn't stop 737MAX advocates here from saying that they'll avoid LionAir like the plague...
First to fly the 787-9
 
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PITingres
Posts: 1307
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Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Tue Feb 18, 2020 12:16 am

Revelation wrote:
LSGL wrote:
Some people are missing the point. Why should EASA ignore the wiring fault? that the issue was not spotted by either Boeing nor the FAA is not a good reason to ignore the problem. That was FAA's mistake, ignoring this after EASA has been informed of this error would place the responsibility on EASA too.

There's no actual wiring fault that's ever been demonstrated, there's a failure to comply with a requirement which is based on theoretical considerations.

There's no one asking EASA to ignore any aspect of this issue.

At this point Boeing has made a proposal to FAA, one which may or may not be accepted, to accept the nonconformance with regard to the wiring regulation based on MAX's similarity with NG and NG's history of never seeing an uncommanded stabilizer activation after its millions of flight hours.

It's an interesting gambit, one I presumed had to be approved at the highest levels of the Boeing company, so if it fails they can't blame the previous regime.

I'm kind of surprised Boeing took this path, it suggests that redoing the wiring will cost a lot of time and money.....


Aside from the time and money, I think Boeing's argument is that moving the wiring is more likely to cause a safety problem than just leaving it alone. To me that makes sense.
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maint123
Posts: 396
Joined: Sun Nov 04, 2018 4:18 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Tue Feb 18, 2020 2:57 am

planecane wrote:
If anybody really wanted to do an MCAS off test without support from Boeing, they could do one of two things:

1) Get the aircraft stable and in trim before the maneuver that they want to evaluate. Turn off the electric trim with the cutout switches. Perform the desired maneuver and evaluate the results. You wouldn't be trimming in the middle of a turn anyway.

2) Perform a test flight with all electric trim on. Have the PNF (who would be a test pilot) listen for or watch the trim wheel and any time it starts to move in manual flight, flick the thumb switch very briefly for nose up trim to stop the MCAS cycle.

Mcas was incorporated for high AoA situations, not for level flight. Taking trials in level flight defeats the purpose of real life situations .
Suppose AoA is high and mcas again misbehaves, the pilot should be able to switch off mcas ,use the wheel solely and land the plane.
The trouble is that in the case of the Ethiopian crash , the pilots after switching mcas off ,couldn't manually fly the plane.
Many here questioned the skill level of the pilots.
So it's only logical that during a climb , with high AoA , the test pilots switch off mcas and manually land the plane.
It's like one engine failing during take off at near max thrust and the 2nd engine safely doing the job. Which is not a uncommon event.
The same level of reliance should be tested out on the mechanicals and aerodynamics of the max .
 
planecane
Posts: 1568
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, February 2020

Tue Feb 18, 2020 3:31 am

maint123 wrote:
planecane wrote:
If anybody really wanted to do an MCAS off test without support from Boeing, they could do one of two things:

1) Get the aircraft stable and in trim before the maneuver that they want to evaluate. Turn off the electric trim with the cutout switches. Perform the desired maneuver and evaluate the results. You wouldn't be trimming in the middle of a turn anyway.

2) Perform a test flight with all electric trim on. Have the PNF (who would be a test pilot) listen for or watch the trim wheel and any time it starts to move in manual flight, flick the thumb switch very briefly for nose up trim to stop the MCAS cycle.

Mcas was incorporated for high AoA situations, not for level flight. Taking trials in level flight defeats the purpose of real life situations .
Suppose AoA is high and mcas again misbehaves, the pilot should be able to switch off mcas ,use the wheel solely and land the plane.
The trouble is that in the case of the Ethiopian crash , the pilots after switching mcas off ,couldn't manually fly the plane.
Many here questioned the skill level of the pilots.
So it's only logical that during a climb , with high AoA , the test pilots switch off mcas and manually land the plane.
It's like one engine failing during take off at near max thrust and the 2nd engine safely doing the job. Which is not a uncommon event.
The same level of reliance should be tested out on the mechanicals and aerodynamics of the max .


I get that. I'm talking about doing a test. The conditions that trigger MCAS are specific (and by this point known to regulators). They can use one of those methods to disable MCAS and put the aircraft into the conditions that normally trigger it to test the handling characteristics if they want to without help from Boeing.

Trimming with the manual wheel is irrelevant to that exercise.
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