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JetBuddy
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:27 pm

In my opinion, it's quite strange that the MAX 8 simulator Ethiopian crews trained on, didn't have MCAS simulated.

I wonder why that is?

Why wasn't MCAS mentioned in the FCOM? Why wasn't it modeled in the flight simulator?
 
Forgedias
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:29 pm

Not sure if this was posted anywhere but Air Canada is grounding their Max's until at least July 1st so at least in Canada, we have an idea of how long the Max's will be grounded since Canada and Europe are conducting their own independent assessment of the 737 Max before they allow it to fly again.

https://globalnews.ca/news/5071188/air- ... il-july-1/
 
dakota123
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:43 pm

Interested wrote:
dakota123 wrote:
Interested wrote:

Does the existing 737 (before max) need MCAS to fly safely? Are we happy with the safety of that plane?

I'm assuming the answer is no followed by yes

If my assumption is correct I simply have no idea why this is even up for debate? They've fudged something that adds extra risk. Worse still Boeing have then tried to hide MCAS and keep it under the radar?? We only know that because of two disasters already that have shown up what's been going on behind closed doors.

That's totally unacceptable in any type of organisation involving health and safety. Let alone airline health and safety! It's disgraceful.

So they've messed up and it can't be allowed to continue? Even if they get the new MCAS risk to the lowest it practically can be it's still a risk we don't need to introduce. A tiny extra percentage risk we don't need leads to too many deaths over the number of flights we would expect from these planes. We reduce and remove risks we don't add them in?

Does the 737 nearest competitor Airbus need MCAS to fly safely ?


Of course it can be allowed to continue. Serious questions here; no snark intended. Or not much, anyway. You think that the FCCs weren’t re-programmed for NEO? You think it didn’t take several iterations of tuning to get the NEO to fly like the CEO? You think Airbus hasn’t screwed up flight controls now and again, and had to go back and patch? There are several human/machine interface design philosophies with the A320 that people have argued have contributed to accidents (this site is rife with those discussions) and given what I know about HMI design, which I did in a former life, there is some validity *to the uninitiated*. But you know what? They’re design decisions, and once understood, in my view they’re a big so what.

Once fixed, fewer pilots will ever experience MCAS than will experience an engine out scenario. And most pilots NEVER experience an engine-out.

Personally, I’m not absolving Boeing of anything. Something went terribly wrong here. But for whatever reason, some of you are hysterical about this.

People with pitchforks are usually wrong (tm).


Again simple questions dakota

Is the need for MCAS adding a risk on to the old 737 that wasn't there before?

Is the Max less safe than the old 737 as a result?

How many extra disasters is ok due to needing MCAS over 10 years on 5,000 planes due to the extra risk? In your opinion

Even the tiniest extra risk. Which we are some way from right now is still going to cause more disasters?


The tiniest extra risk? 1) I don’t accept that there will be ultimately based on what is known today. 2) That’s not how the real world works. Safety trade-offs and educated guesses are made every day in the aero industry and in every other — why else are the ADs?

Larger fan blades, gearboxes, hotter cores, 60:1 pressure ratios, LP cores spinning at twice the rpm of previous designs — THOSE are some of the things that we think we understand but maybe don’t fully just yet.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
MSPNWA
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:46 pm

Forgedias wrote:
Not sure if this was posted anywhere but Air Canada is grounding their Max's until at least July 1st so at least in Canada, we have an idea of how long the Max's will be grounded since Canada and Europe are conducting their own independent assessment of the 737 Max before they allow it to fly again.

https://globalnews.ca/news/5071188/air- ... il-july-1/


Old news, and it's not the correct characterization from the press. AC is removing it from their schedules until July 1st. They are not saying they will be grounded until then.
 
Interested
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:50 pm

dakota123 wrote:
Interested wrote:
dakota123 wrote:

Of course it can be allowed to continue. Serious questions here; no snark intended. Or not much, anyway. You think that the FCCs weren’t re-programmed for NEO? You think it didn’t take several iterations of tuning to get the NEO to fly like the CEO? You think Airbus hasn’t screwed up flight controls now and again, and had to go back and patch? There are several human/machine interface design philosophies with the A320 that people have argued have contributed to accidents (this site is rife with those discussions) and given what I know about HMI design, which I did in a former life, there is some validity *to the uninitiated*. But you know what? They’re design decisions, and once understood, in my view they’re a big so what.

Once fixed, fewer pilots will ever experience MCAS than will experience an engine out scenario. And most pilots NEVER experience an engine-out.

Personally, I’m not absolving Boeing of anything. Something went terribly wrong here. But for whatever reason, some of you are hysterical about this.

People with pitchforks are usually wrong (tm).


Again simple questions dakota

Is the need for MCAS adding a risk on to the old 737 that wasn't there before?

Is the Max less safe than the old 737 as a result?

How many extra disasters is ok due to needing MCAS over 10 years on 5,000 planes due to the extra risk? In your opinion

Even the tiniest extra risk. Which we are some way from right now is still going to cause more disasters?


The tiniest extra risk? 1) I don’t accept that there will be ultimately based on what is known today. 2) That’s not how the real world works. Safety trade-offs and educated guesses are made every day in the aero industry and in every other — why else are the ADs?

Larger fan blades, gearboxes, hotter cores, 60:1 pressure ratios, LP cores spinning at twice the rpm of previous designs — THOSE are some of the things that we think we understand but maybe don’t fully just yet.


But aren't they just an improvement on previous proven systems not a new system with added risk. And not extra information or training for pilots to worry about? There's a big difference.

What about answers to my questions above?

I'm interested what you think?
 
dakota123
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:55 pm

Interested wrote:
dakota123 wrote:
Interested wrote:

I think there are two issues here

Number one ) obviously all concerned in the short term at least work their hardest to make the plane as it is as safe as it can be despite using MCAS

Number two) separate to that the world decides whether or not it's acceptable to launch a plane that is by its very design less safe than the plane it replaces

I simply cannot believe the second will be allowed to happen UNLESS money overrides our safety

In the event number two does happen i hope the airlines and customers move their orders and business to other suppliers regardless over time to show Boeing what they have done is unacceptable and they can't get away with it


Other than the FUBAR implementation, there is currently no reason to *rationally* think Max is less safe than NG. For all we know, MCAS is there *only* to make it fly more like the NG *in that small area of the flight envelope*. You are espousing facts not in evidence to this point.


So we can get rid of MCAS then?


Maybe, yes, but then the common type rating could be lost. Or maybe loss of MCAS could be trained with respect to that flight regime. Most likely it would be a land at earliest opportunity situation. In any case, Boeing sure isn’t claiming a big fat “never mind”.

Given that initially only 0.6* of ND trim was to be needed, clearly something didn’t pan out the way the engineers thought it would. But the fact that even now there doesn’t seem to be any rate of change response required (AOA increasing rapidly so shove the nose down more quickly) argues that the issue isn’t dire. I mean, MCAS as it’s been described seems to be as “dumb” a system as there is.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
sxf24
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 5:59 pm

PW100 wrote:
Boof02671 wrote:
Yes AA, WN and and UA sent union and management pilots to Boeing.

Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?


I know other foreign operators and regulators that are also invited to Seattle in the coming week to review the upcoming changes and training. There appears to be a multitrack process with the FAA and other regulators.
 
smartplane
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:17 pm

How do the visitors know they are seeing the patch on a 'real', warts and all, MAX simulator?

Do they get to see and experience the before and after?

Is data from the two MAX's that crashed also used, at low altitude, and is the outcome consistently different / better?
 
jplatts
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:21 pm

Why hasn't WN had any crashes involving the 737 MAX 8 during the 17 months that it operated the MAX 8 planes?

WN 1380 was the only incident at WN during the October 2017 through March 2019 time period that resulted in a fatality, but the WN 1380 incident occurred on a 737-700 plane that was almost 18 years old.

Any safety issues involving both WN's 737 MAX planes and the oldest 737-700's in WN's fleet must be addressed.
 
WIederling
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:23 pm

dakota123 wrote:
Larger fan blades, gearboxes, hotter cores, 60:1 pressure ratios, LP cores spinning at twice the rpm of previous designs — THOSE are some of the things that we think we understand but maybe don’t fully just yet.


More or less a distraction what you write.
This is about integrating a completely safe engine on an up to now rather save airframe resulting
in a product that has an unpleasant tendency to crash.
superficially about 20..40 times more often than for the predecessors.
Acceptable:
MCAS related crashes would have to have a very small impact on the regular crashrate.
Murphy is an optimist
 
Boof02671
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:23 pm

PW100 wrote:
Boof02671 wrote:
Yes AA, WN and and UA sent union and management pilots to Boeing.

Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?

Not my choice, ask Boeing. And none of us know who else was invited or attended
 
Boof02671
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:26 pm

Interested wrote:
art wrote:
Interested wrote:
Someone explain to me a valid reason why we allow planes that aren't stable to be designed and approved in the first place?


Why did Boeing choose to design an unstable aircraft? I think the answer is straightforward: they did not want to let Airbus' A320 gain and hold a decisive edge over the 737 for several years. To me it is also possible that they thought they would lose customers to Bombardier if all they had to compete with the CS3000 was the 737-700.

Regarding why this desiign was approved, I think that's a question to put to the FAA. They certified it.


There's an article in New York Times today saying that a few years back the CEO of AA called the CEO of Boeing to say they were on the verge of giving a 100 plane order to airbus. Boeing then promised a new version of 737 (the max) within 6 years to keep the business. And so the rush job began. In comparison had they designed a new plane from scratch it would have taken 10 years and they would have lost the big order from AA

False AA split their narrowbody order between Airbus and Boeing and the order was more than a few years ago, it was before AA filed bankruptcy.
 
washingtonflyer
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:27 pm

Boof02671 wrote:


That may be true but I've now heard AA is expected to extend its grounding until 4/24.
 
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PixelFlight
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:28 pm

sgrow787 wrote:
PixelFlight wrote:

No, the problem is in the design. The MCAS function was added into the FCC where the STS function already was. For some reason, only the automatic control (AP) was implemented with both sensors comparison. The manual control already use only a single sensor before the MCAS was added. Details:
https://www.satcom.guru/2018/11/737-fcc ... mmand.html


But Satcom Guru says:

"Based on information available, in all three cases of autopilot augmentation, only one FCC produces the valid command, and that FCC command is based only a single sensor set."

But it mentions two CPUs, which I would assume exist within one FCC (two FCCs mean a total of four CPUs):

"While the autopilot is engaged, both CPUs are utilized to ensure a single CPU error is detected."

Funny that you quoted the same source but got a different interpretation of it.

Yes.

Wording issue. To understand correctly you have to split:
1) the description that is about the autopilot control (autopilot engaged) vs about the manual control (manual flight/autopilot disengaged) where the "autopilot augmentation" is still active. Yes the wording choice is confusing.
2) the description that is about the commands for the stab trim vs about all others commands.

Yes there are 4 CPUs in total (2 in each FCCs), but only a single CPU that process the MCAS function in manual flight and from a single AoA sensor. (underlined part is officially confirmed by both Boeing and the FAA). If you read carefully the details of the Satcom Guru description, you realize that the wording "in manual flight only" (from the EAD) is the exact consequence of the processing design. I don't know the reason of that design, but I can imagine that in could cam from the "split side design" history of the 737.
 
Chemist
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:29 pm

art wrote:
Interested wrote:
Someone explain to me a valid reason why we allow planes that aren't stable to be designed and approved in the first place?


Why did Boeing choose to design an unstable aircraft? I think the answer is straightforward: they did not want to let Airbus' A320 gain and hold a decisive edge over the 737 for several years. To me it is also possible that they thought they would lose customers to Bombardier if all they had to compete with the CS3000 was the 737-700.

Regarding why this desiign was approved, I think that's a question to put to the FAA. They certified it.


This is ridiculously hyperbolic.
They didn't "design an unstable aircraft". They modified pyons and added larger engines. Their modeling didn't suggest any adverse effects. Once in flight test, some unexpected pitch behavior was noted ony at high AOAs. They put a (flawed) software solution in place to address that edge case. Plenty of aircraft have edge case handling issues that are solved with software, or with strakes or tabs or a variety of other solutions. This is normal. What isn't normal is the behavior of Boeing's poorly designed solution.
 
Boof02671
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:30 pm

washingtonflyer wrote:
Boof02671 wrote:


That may be true but I've now heard AA is expected to extend its grounding until 4/24.

I’m the one who posted AA expects them to be grounded till 4/24.
 
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hilram
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:34 pm

kalvado wrote:
PW100 wrote:
Boof02671 wrote:
Yes AA, WN and and UA sent union and management pilots to Boeing.

Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?

Look at it this way: fix will be tested on US flying public first.

:lol:

Too true! Wouldn't trust the newly revised MCAS into the hands of 3rd World Pilots, would we? :stirthepot:
Flown on: A319, 320, 321, 332, 333, 343 | B732, 734, 735, 736, 73G, 738, 743, 744, 772, 77W | BAe-146 | DHC-6, 7, 8 | F50 | E195 | MD DC-9 41, MD-82, MD-87
 
dakota123
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:52 pm

WIederling wrote:
dakota123 wrote:
Larger fan blades, gearboxes, hotter cores, 60:1 pressure ratios, LP cores spinning at twice the rpm of previous designs — THOSE are some of the things that we think we understand but maybe don’t fully just yet.


More or less a distraction what you write.
This is about integrating a completely safe engine on an up to now rather save airframe resulting
in a product that has an unpleasant tendency to crash.
superficially about 20..40 times more often than for the predecessors.
Acceptable:
MCAS related crashes would have to have a very small impact on the regular crashrate.


This whole discussion is a distraction. MAX with properly designed MCAS will be as safe as NG. At least, any discussion otherwise is just speculation put out as unassailable fact by a few. And frankly, how do we know the engines are completely safe? Took quite a while for the CF6-80 dovetail slot issue to show.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
Chemist
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:56 pm

hilram wrote:
kalvado wrote:
PW100 wrote:
Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?

Look at it this way: fix will be tested on US flying public first.

:lol:

Too true! Wouldn't trust the newly revised MCAS into the hands of 3rd World Pilots, would we? :stirthepot:


Statistically the third world air travel is substantially less safe, with similar equipment. Make of that what you want.
 
WIederling
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 6:59 pm

Chemist wrote:
Their modeling didn't suggest any adverse effects.


Then the B engineering department would be composed of fumbling idiots.
Which I think is definitely not the case.

They've been playing around with a further reengine as back up measure for quite some
before going to the MAX. ( see Leeham quoting some B bigwig.)
They changed the tail quite a bit for cleaner airflow ( does that improve authority for the tail surfaces? I'd guess so :-)

Chemist wrote:
Once in flight test, some unexpected pitch behavior was noted only at high AOAs.

I'd imagine "turning up the volume" on the "trim max displacement" allowed per go for MCAS
was such a thing. But not MCAS as such.
Murphy is an optimist
 
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SheikhDjibouti
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:01 pm

Chemist wrote:
They didn't "design an unstable aircraft". They modified pyons and added larger engines. Their modeling didn't suggest any adverse effects. Once in flight test, some unexpected pitch behavior was noted ony at high AOAs. They put a (flawed) software solution in place to address that edge case. Plenty of aircraft have edge case handling issues that are solved with software, or with strakes or tabs or a variety of other solutions. This is normal. What isn't normal is the behavior of Boeing's poorly designed solution.


I have a slightly different version of that story;
I believe their modelling did suggest adverse effects; basically once they had moved the engine forward it was a no-brainer.
I don't know why you would imagine it any other way?
Consequently Boeing introduced MCAS with a 0.6deg limit of action.
Then, once in flight test, this was found to be insufficient and they increased it to 2.5deg. (equivalent to maximum deflection in two iterations)

At this point I don't have a link on my desktop to back up my statement, and I'm not going to turn my filing system upside down just to find it.
What do you have to support your version?
Nothing to see here; move along please.
 
kalvado
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:08 pm

dakota123 wrote:
WIederling wrote:
dakota123 wrote:
Larger fan blades, gearboxes, hotter cores, 60:1 pressure ratios, LP cores spinning at twice the rpm of previous designs — THOSE are some of the things that we think we understand but maybe don’t fully just yet.


More or less a distraction what you write.
This is about integrating a completely safe engine on an up to now rather save airframe resulting
in a product that has an unpleasant tendency to crash.
superficially about 20..40 times more often than for the predecessors.
Acceptable:
MCAS related crashes would have to have a very small impact on the regular crashrate.


This whole discussion is a distraction. MAX with properly designed MCAS will be as safe as NG. At least, any discussion otherwise is just speculation put out as unassailable fact by a few. And frankly, how do we know the engines are completely safe? Took quite a while for the CF6-80 dovetail slot issue to show.

Did you see all applicable documents first hand? Until you did, You statement is just a speculation put out as unassailable fact.
We have to trust FAA and Boeing statement that everything is in great shape (aka certification), and looks like they managed to miss at least something important. Any reason why you think mcas is the only problem?
 
Doggone83
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:23 pm

I'm new and can only figure out how to reply. So I guess I'll have to use "reply" even though this is not a reply.
Here is excellent info from a pilot's perspective (I'm not the pilot):
 
art
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:23 pm

Jshank83 wrote:
I think they will be in the air by May (at the very least June when summer flying picks up). They already have the fix and pilots testing it in the sims. Once they decide it is okay it can't take that long to load it on planes. Assuming there are no hardware changes (besides maybe adding a light). I can't see it taking all that long. The idea that they will NEVER fly again is crazy. Way too much money has been invested in them to not have them fly again, even if it means bigger fixes.

I also don't think there will be that many people actively avoiding it to make it matter.


If the MAX grounding is lifted and there is another accident where the crew report pitch control problems either through

(a) MCAS malfunctioning or
(b) the aircraft being flown with MCAS switched off after malfunction

then I think it will be grounded and almost certainly never fly passengers again. Whether Boeing had invested $1 billion or $10 billion or $100 billion would not be of any importance. I hope there will be no further pitch problem induced accidents but if there were when Boeing had built / contracted parts to build 1000 then I would see them facing a bill nearer to $100 billion than $50 billion.

If the MAX brand becpmes poisonous then I think airlines will try to avoid ordering it. I say "try" since Airbus and Boeing build over 50 NB's a month each at the moment and Airbus could not quicklly double its output to 100 a month if airlines wanted to switch away from Boeing. No equivalents are available - MC-21 from Irkut is not ready (sanctions problem, too), C919 from Comac has not entered production.
 
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PW100
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:34 pm

sxf24 wrote:
PW100 wrote:
Boof02671 wrote:
Yes AA, WN and and UA sent union and management pilots to Boeing.

Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?


I know other foreign operators and regulators that are also invited to Seattle in the coming week to review the upcoming changes and training. There appears to be a multitrack process with the FAA and other regulators.


That would be the rational thing for Boeing to do: multi track approach, having the main certifying agencies (FAA, EASA, TCCA) as well as Indonesian and Ethiopian representatives all on-site, and be very very open to all thinkable aspects. Even if that means a delay of a couple days or even weeks.
I do expect that those agencies want to dig fairly deep into the initial design specifics, as well as flight test results, to understand the initial position, only then one can judge the changes to software and training.

BTW, do you know if Boeing has completed the flight testing of the fix? From the Seattle Times article, we learned that Boeing significantly modified MCAS specs and authority as a result of flight testing. I'd expect that that part of the flight testing need to be replicated to validate the new MCAS specs (although I assume that most will be available form simulation and know flight data). But in any case, Beoing will have to satisfy "the agencies", flight testing would probably be required to get a acceptable level of trust.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
smokeybandit
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:41 pm

washingtonflyer wrote:
Boof02671 wrote:


That may be true but I've now heard AA is expected to extend its grounding until 4/24.


Well a month to install the fix across the fleet and test out, give pilots the new training. Seems reasonable.
 
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PW100
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:44 pm

Boof02671 wrote:
PW100 wrote:
Boof02671 wrote:
Yes AA, WN and and UA sent union and management pilots to Boeing.

Shouldn't Boeing invite some "third world pilots" to determine if their fix is also good for the rest of the world . . . ?

Not my choice, ask Boeing. And none of us know who else was invited or attended


I wasn't expecting an answer, as I thought the sarcasm bit was fairly obvious . . .
In any case, I trust that Boeing will invite *a lot* of parties, and the review will be very thorough.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
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PW100
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 7:48 pm

Chemist wrote:
hilram wrote:
kalvado wrote:
Look at it this way: fix will be tested on US flying public first.

:lol:

Too true! Wouldn't trust the newly revised MCAS into the hands of 3rd World Pilots, would we? :stirthepot:


Statistically the third world air travel is substantially less safe, with similar equipment. Make of that what you want.


While true to some level, there is still an awful lot of light between "substantially less safe" and MAX accident rate of 50 - 200 times worse than that of comparable product like 737NG - which btw is also operated by the same "third world operators", and does not appear to be affected so much.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
Amiga500
Posts: 2267
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 8:06 pm

dakota123 wrote:
Bullsh*t. No more a kludge than Mach trim or rudder limiters.


I suggest you go try and understand the FARs (in this case, specifically 25.103 and 25.203 - and might as well look at 25.672 while you are at it) to see why one is a kludge and the others are accepted means of improving control and/or safety.
 
dakota123
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Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 8:10 pm

Amiga500 wrote:
dakota123 wrote:
Bullsh*t. No more a kludge than Mach trim or rudder limiters.


I suggest you go try and understand the FARs (in this case, specifically 25.103 and 25.203 - and might as well look at 25.672 while you are at it) to see why one is a kludge and the others are accepted means of improving control and/or safety.


Many, many times, thank you very much. How do you think they got to be accepted in the first place? In many cases, only after an issue presented itself for the first time.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
dakota123
Posts: 233
Joined: Wed Aug 30, 2006 11:03 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 8:17 pm

kalvado wrote:
dakota123 wrote:
WIederling wrote:

More or less a distraction what you write.
This is about integrating a completely safe engine on an up to now rather save airframe resulting
in a product that has an unpleasant tendency to crash.
superficially about 20..40 times more often than for the predecessors.
Acceptable:
MCAS related crashes would have to have a very small impact on the regular crashrate.


This whole discussion is a distraction. MAX with properly designed MCAS will be as safe as NG. At least, any discussion otherwise is just speculation put out as unassailable fact by a few. And frankly, how do we know the engines are completely safe? Took quite a while for the CF6-80 dovetail slot issue to show.

Did you see all applicable documents first hand? Until you did, You statement is just a speculation put out as unassailable fact.
We have to trust FAA and Boeing statement that everything is in great shape (aka certification), and looks like they managed to miss at least something important. Any reason why you think mcas is the only problem?


Did you? Your reading comprehension needs help — note my caveat? How about some intellectual honesty.

You. Don’t. Know. And neither do I.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
kalvado
Posts: 1820
Joined: Wed Mar 01, 2006 4:29 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 8:39 pm

dakota123 wrote:
kalvado wrote:
dakota123 wrote:

This whole discussion is a distraction. MAX with properly designed MCAS will be as safe as NG. At least, any discussion otherwise is just speculation put out as unassailable fact by a few. And frankly, how do we know the engines are completely safe? Took quite a while for the CF6-80 dovetail slot issue to show.

Did you see all applicable documents first hand? Until you did, You statement is just a speculation put out as unassailable fact.
We have to trust FAA and Boeing statement that everything is in great shape (aka certification), and looks like they managed to miss at least something important. Any reason why you think mcas is the only problem?


Did you? Your reading comprehension needs help — note my caveat? How about some intellectual honesty.

You. Don’t. Know. And neither do I.

There is a difference between our statements here. I am just describing existing problem, nothing more nothing less. What you're saying qualifies as a forward-looking statement:
dakota123 wrote:
MAX with properly designed MCAS will be as safe as NG. .

Until you have factual knowledge to support it, you statement is, let me reiterate,
dakota123 wrote:

just a speculation put out as unassailable fact.
 
chance6
Posts: 9
Joined: Wed Mar 13, 2019 12:38 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 8:43 pm

Carlos01 wrote:
dampfnudel wrote:
I wouldn’t be surprised if Lion Air is next to cancel their MAX order. I’m sure Boeing is crossing their fingers right about now that the Chinese carriers don’t get any ideas.


First of all they have to rename the plane. Anything with "MAX" -attached to it will more or less equal to "death" in the eyes of the consumers. The Chinese are no different, actually they are even very superstitious, so it's just a matter of time before the cancellations start rolling in.

Then completely another question will be, is the plane even possible to fix? It could well be that before all authorities are happy with it, such major structural changes are required, that it more or less voids the whole business case, and they just have to go with a clean-sheet.

And since we are in the grounding-thread, Boeing would be so much better off in case they would have grounded the MAX-fleet immediately after the first crash. They could have fixed it in peace and quiet, and probably gotten away with the whole thing. But now due to their greed, the shite hit the fan big time, and they will pay a price so high that even the whole company could go bust. Somebody could ask the CEO, how does he himself think he managed the situation, all good?



Boeing handled it horribly. Outsourcing jobs and making quick fixes. NOBODY in their right mind would have certified this under proper oversight. ONE sensor causing a crash? No real redundancy here? You need 3 sensors to all show an issue in order for this type of control to kick in.
Not only does Boeing suffer but GE/CFM will suffer from it- grounded aircraft means less servicing which is where engine profits are really made. Airlines cancelling orders will mean profit impacts at the engine makers. So get ready, P&W, you're about to get even busier.
 
bob75013
Posts: 826
Joined: Tue Jun 23, 2015 5:05 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:07 pm

chance6 wrote:
Carlos01 wrote:
dampfnudel wrote:
I wouldn’t be surprised if Lion Air is next to cancel their MAX order. I’m sure Boeing is crossing their fingers right about now that the Chinese carriers don’t get any ideas.


First of all they have to rename the plane. Anything with "MAX" -attached to it will more or less equal to "death" in the eyes of the consumers. The Chinese are no different, actually they are even very superstitious, so it's just a matter of time before the cancellations start rolling in.

Then completely another question will be, is the plane even possible to fix? It could well be that before all authorities are happy with it, such major structural changes are required, that it more or less voids the whole business case, and they just have to go with a clean-sheet.

And since we are in the grounding-thread, Boeing would be so much better off in case they would have grounded the MAX-fleet immediately after the first crash. They could have fixed it in peace and quiet, and probably gotten away with the whole thing. But now due to their greed, the shite hit the fan big time, and they will pay a price so high that even the whole company could go bust. Somebody could ask the CEO, how does he himself think he managed the situation, all good?



Boeing handled it horribly. Outsourcing jobs and making quick fixes. NOBODY in their right mind would have certified this under proper oversight. ONE sensor causing a crash? No real redundancy here? You need 3 sensors to all show an issue in order for this type of control to kick in.
Not only does Boeing suffer but GE/CFM will suffer from it- grounded aircraft means less servicing which is where engine profits are really made. Airlines cancelling orders will mean profit impacts at the engine makers. So get ready, P&W, you're about to get even busier.


So is your aeronautical experience limited to that which you learned in your one week on a-ner?
 
Chemist
Posts: 540
Joined: Tue Oct 20, 2015 4:46 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:07 pm

WIederling wrote:
Chemist wrote:
Their modeling didn't suggest any adverse effects.


Then the B engineering department would be composed of fumbling idiots.
Which I think is definitely not the case.

They've been playing around with a further reengine as back up measure for quite some
before going to the MAX. ( see Leeham quoting some B bigwig.)
They changed the tail quite a bit for cleaner airflow ( does that improve authority for the tail surfaces? I'd guess so :-)

Chemist wrote:
Once in flight test, some unexpected pitch behavior was noted only at high AOAs.

I'd imagine "turning up the volume" on the "trim max displacement" allowed per go for MCAS
was such a thing. But not MCAS as such.


CFD modeling doesn't always uncover all issues. That's why you flight test. Airbus does it too.
 
Heinkel
Posts: 222
Joined: Sun Sep 08, 2013 6:15 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:08 pm

dakota123 wrote:
This whole discussion is a distraction. MAX with properly designed MCAS will be as safe as NG. At least, any discussion otherwise is just speculation put out as unassailable fact by a few. And frankly, how do we know the engines are completely safe? Took quite a while for the CF6-80 dovetail slot issue to show.


If an engine fails, the pilots shut it off. Typically the loss of one engine doesn't let an aircraft fly full speed into the ground.
 
Chemist
Posts: 540
Joined: Tue Oct 20, 2015 4:46 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:11 pm

SheikhDjibouti wrote:
Chemist wrote:
They didn't "design an unstable aircraft". They modified pyons and added larger engines. Their modeling didn't suggest any adverse effects. Once in flight test, some unexpected pitch behavior was noted ony at high AOAs. They put a (flawed) software solution in place to address that edge case. Plenty of aircraft have edge case handling issues that are solved with software, or with strakes or tabs or a variety of other solutions. This is normal. What isn't normal is the behavior of Boeing's poorly designed solution.


I have a slightly different version of that story;
I believe their modelling did suggest adverse effects; basically once they had moved the engine forward it was a no-brainer.
I don't know why you would imagine it any other way?
Consequently Boeing introduced MCAS with a 0.6deg limit of action.
Then, once in flight test, this was found to be insufficient and they increased it to 2.5deg. (equivalent to maximum deflection in two iterations)

At this point I don't have a link on my desktop to back up my statement, and I'm not going to turn my filing system upside down just to find it.
What do you have to support your version?


Well I guess neither of us have those links. I read to the effect of what I stated and don't remember where. My info could be wrong and so could yours.
Moving the engine forward (re:CG change) would be obvious and accomodated. Not so sure about high AOA behavior.
The point being that all the "deliberately unstable" accusations don't seem to be founded by any real evidence that I've seen. Lots of accusations without any substance.
 
chance6
Posts: 9
Joined: Wed Mar 13, 2019 12:38 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:35 pm

bob75013 wrote:
chance6 wrote:
Carlos01 wrote:

First of all they have to rename the plane. Anything with "MAX" -attached to it will more or less equal to "death" in the eyes of the consumers. The Chinese are no different, actually they are even very superstitious, so it's just a matter of time before the cancellations start rolling in.

Then completely another question will be, is the plane even possible to fix? It could well be that before all authorities are happy with it, such major structural changes are required, that it more or less voids the whole business case, and they just have to go with a clean-sheet.

And since we are in the grounding-thread, Boeing would be so much better off in case they would have grounded the MAX-fleet immediately after the first crash. They could have fixed it in peace and quiet, and probably gotten away with the whole thing. But now due to their greed, the shite hit the fan big time, and they will pay a price so high that even the whole company could go bust. Somebody could ask the CEO, how does he himself think he managed the situation, all good?



Boeing handled it horribly. Outsourcing jobs and making quick fixes. NOBODY in their right mind would have certified this under proper oversight. ONE sensor causing a crash? No real redundancy here? You need 3 sensors to all show an issue in order for this type of control to kick in.
Not only does Boeing suffer but GE/CFM will suffer from it- grounded aircraft means less servicing which is where engine profits are really made. Airlines cancelling orders will mean profit impacts at the engine makers. So get ready, P&W, you're about to get even busier.


So is your aeronautical experience limited to that which you learned in your one week on a-ner?



Not a very interesting question, BUT it was inflammatory. Is your experience based on 4 years?
Simple statement about customer perception. The MCAS wasn't fully vetted and a DFMEA should have exposed it as being incomplete, IF indeed they aren't just shuffling papers around and running some analysis. Sounds like increased oversight on this upcoming "Fix" will be quite necessary. And the engine makers supplying this aircraft had better get real interested, too.
But thanks for your inflammatory, cocky, and unnecessary question.
 
frmrCapCadet
Posts: 3003
Joined: Thu May 29, 2008 8:24 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:55 pm

As I understand it Boeing would not need a separate certification for MAX pilots should they require some specific type training for the MAX. Airlines would need to pay attention to who had and who didn't until all pilots had received the training. Assumedly all future 737 pilots would understand the MAX had a specific difference, and have received the training.
Buffet: the airline business...has eaten up capital...like..no other (business)
 
osiris30
Posts: 2655
Joined: Sat Sep 30, 2006 10:16 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:58 pm

Interested wrote:
dakota123 wrote:
Interested wrote:

I think there are two issues here

Number one ) obviously all concerned in the short term at least work their hardest to make the plane as it is as safe as it can be despite using MCAS

Number two) separate to that the world decides whether or not it's acceptable to launch a plane that is by its very design less safe than the plane it replaces

I simply cannot believe the second will be allowed to happen UNLESS money overrides our safety

In the event number two does happen i hope the airlines and customers move their orders and business to other suppliers regardless over time to show Boeing what they have done is unacceptable and they can't get away with it


Other than the FUBAR implementation, there is currently no reason to *rationally* think Max is less safe than NG. For all we know, MCAS is there *only* to make it fly more like the NG *in that small area of the flight envelope*. You are espousing facts not in evidence to this point.


So we can get rid of MCAS then?


See here's the problem.. you have asked this question directly or indirectly in multiple threads now, which shows you are merely TROLLING the forum. Hopefully the rest of the readership here will go read through your post history. You asked this in the ET thread multiple times. It was explained multiple times why MCAS is 'needed' (hint it's not for the safety of the plane, it is for regulatory 'feel' compliance with the type it shares a cert with). Yet you keep asking the same question. You aren't trying to learn anything, you are trying to advance an argument and don't even display the courage to do it directly.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
User avatar
ODwyerPW
Posts: 1500
Joined: Thu Dec 09, 2004 6:30 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 9:58 pm

I have a question specific to the MCAS fixes that are being implemented. I've read the last few pages and I can't find comments.... So I want to make sure if I have an accurate understanding of the fix that will be applied:

1. AOA Sensors...3 now going to be standard? Such that when there is disagreement, a pilot should at least have 2 of the 3 in agreement (within a reasonable threshold of fractions of an angle)....
2. The now standard 'AOA Disagreement Alarm' will look at disagreement (within a reasonable threshold of fractions of an angle) between the 3 sensors?
3. All AOA Sensor readings will be available to operators.... with clear indication of the one that is suspect to be faulty/out of agreement,,, and clear indication of the one that is being used by MCAS.
4. At this point Operator can decide to turn off MCAS or the software will have the ability to switch to one of the two remaining sensors that are in agreement after the Pilot has acknowledged the 'AOA Disareement Alarm' and opted not to turn off of MCAS.
5. Followup Training on all of this.

Is this the solution being applied?Is it this comprehensive? Triple Redundancy is better because it allows us to determine there is disagreement... and point out who is more like at fault.... With two.... well unless the faulty one is reading really really bad... it's hard to determine with reading is the faulty and which is the accurate.... Triple Redundancy makes you more sure...

Air speed indications.... How much redundancy is there? Will slow speeds trigger MCAS to pitch the nose down to try to gather speed to prevent Stall? Or is MCAS soley concerned with AOA?
learning never stops.
 
osiris30
Posts: 2655
Joined: Sat Sep 30, 2006 10:16 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 10:02 pm

ODwyerPW wrote:
I have a question specific to the MCAS fixes that are being implemented. I've read the last few pages and I can't find comments.... So I want to make sure if I have an accurate understanding of the fix that will be applied:

1. AOA Sensors...3 now going to be standard? Such that when there is disagreement, a pilot should at least have 2 of the 3 in agreement (within a reasonable threshold of fractions of an angle)....
2. The now standard 'AOA Disagreement Alarm' will look at disagreement (within a reasonable threshold of fractions of an angle) between the 3 sensors?
3. All AOA Sensor readings will be available to operators.... with clear indication of the one that is suspect to be faulty/out of agreement,,, and clear indication of the one that is being used by MCAS.
4. At this point Operator can decide to turn off MCAS or the software will have the ability to switch to one of the two remaining sensors that are in agreement after the Pilot has acknowledged the 'AOA Disareement Alarm' and opted not to turn off of MCAS.
5. Followup Training on all of this.

Is this the solution being applied?Is it this comprehensive? Triple Redundancy is better because it allows us to determine there is disagreement... and point out who is more like at fault.... With two.... well unless the faulty one is reading really really bad... it's hard to determine with reading is the faulty and which is the accurate.... Triple Redundancy makes you more sure...

Air speed indications.... How much redundancy is there? Will slow speeds trigger MCAS to pitch the nose down to try to gather speed to prevent Stall? Or is MCAS soley concerned with AOA?


1) 3 isn't an option and never was, that was media misspeak.
2) yes between the 2 sensors
3) not sure that has been stated clearly either way
4) MCAS will disable I believe
5) Yes
6) Unknown authority limits on MCAS will be introduced.

[edit] airspeed isn't needed.. the AoA vanes don't need airspeed.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
Interested
Posts: 647
Joined: Thu May 19, 2016 12:19 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 10:49 pm

Chemist wrote:
SheikhDjibouti wrote:
Chemist wrote:
They didn't "design an unstable aircraft". They modified pyons and added larger engines. Their modeling didn't suggest any adverse effects. Once in flight test, some unexpected pitch behavior was noted ony at high AOAs. They put a (flawed) software solution in place to address that edge case. Plenty of aircraft have edge case handling issues that are solved with software, or with strakes or tabs or a variety of other solutions. This is normal. What isn't normal is the behavior of Boeing's poorly designed solution.


I have a slightly different version of that story;
I believe their modelling did suggest adverse effects; basically once they had moved the engine forward it was a no-brainer.
I don't know why you would imagine it any other way?
Consequently Boeing introduced MCAS with a 0.6deg limit of action.
Then, once in flight test, this was found to be insufficient and they increased it to 2.5deg. (equivalent to maximum deflection in two iterations)

At this point I don't have a link on my desktop to back up my statement, and I'm not going to turn my filing system upside down just to find it.
What do you have to support your version?


Well I guess neither of us have those links. I read to the effect of what I stated and don't remember where. My info could be wrong and so could yours.
Moving the engine forward (re:CG change) would be obvious and accomodated. Not so sure about high AOA behavior.
The point being that all the "deliberately unstable" accusations don't seem to be founded by any real evidence that I've seen. Lots of accusations without any substance.


Deliberately unstable?

Don't think anyone's suggested it was deliberate. But they've messed up and then tried to hide their fix from pilots and airlines etc. That was deliberate
 
Interested
Posts: 647
Joined: Thu May 19, 2016 12:19 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 10:51 pm

osiris30 wrote:
Interested wrote:
dakota123 wrote:

Other than the FUBAR implementation, there is currently no reason to *rationally* think Max is less safe than NG. For all we know, MCAS is there *only* to make it fly more like the NG *in that small area of the flight envelope*. You are espousing facts not in evidence to this point.


So we can get rid of MCAS then?


See here's the problem.. you have asked this question directly or indirectly in multiple threads now, which shows you are merely TROLLING the forum. Hopefully the rest of the readership here will go read through your post history. You asked this in the ET thread multiple times. It was explained multiple times why MCAS is 'needed' (hint it's not for the safety of the plane, it is for regulatory 'feel' compliance with the type it shares a cert with). Yet you keep asking the same question. You aren't trying to learn anything, you are trying to advance an argument and don't even display the courage to do it directly.


Please show me where ive asked if we can get rid if MCAS elsewhere in the last few days. I may have in the past when I was educating myself on here. I don't think we can based on what I've learnt. This poster suggested it was unimportant so hence I asked them if it was really needed then?

I'm not trolling anyone. I'm just taking part in each Max thread?
 
Chemist
Posts: 540
Joined: Tue Oct 20, 2015 4:46 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 11:01 pm

Interested wrote:
Chemist wrote:
SheikhDjibouti wrote:

I have a slightly different version of that story;
I believe their modelling did suggest adverse effects; basically once they had moved the engine forward it was a no-brainer.
I don't know why you would imagine it any other way?
Consequently Boeing introduced MCAS with a 0.6deg limit of action.
Then, once in flight test, this was found to be insufficient and they increased it to 2.5deg. (equivalent to maximum deflection in two iterations)

At this point I don't have a link on my desktop to back up my statement, and I'm not going to turn my filing system upside down just to find it.
What do you have to support your version?


Well I guess neither of us have those links. I read to the effect of what I stated and don't remember where. My info could be wrong and so could yours.
Moving the engine forward (re:CG change) would be obvious and accomodated. Not so sure about high AOA behavior.
The point being that all the "deliberately unstable" accusations don't seem to be founded by any real evidence that I've seen. Lots of accusations without any substance.



Deliberately unstable?

Don't think anyone's suggested it was deliberate. But they've messed up and then tried to hide their fix from pilots and airlines etc. That was deliberate


When people say they "designed an unstable aircraft" that implies intent, as a design is an intended construction.
No disagreement that they messed up - on the implementation of MCAS. I suspect it was negligence rather than malice or deception where they thought their fix was going to essentially make the flying characteristics extremely similar to the NG. Clearly they screwed up and then they spun that in a shameful way. I would agree that the spin was shameful, and the screwups were shameful. But for anybody to claim that Boeing decided safety wasn't important is a stretch. They had business pressures and that caused safety issues. But it wasn't intent to be unsafe.
 
jplatts
Posts: 2685
Joined: Sat Mar 18, 2017 6:42 pm

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 11:07 pm

chance6 wrote:
Not only does Boeing suffer but GE/CFM will suffer from it- grounded aircraft means less servicing which is where engine profits are really made. Airlines cancelling orders will mean profit impacts at the engine makers. So get ready, P&W, you're about to get even busier.


There are actually Airbus A319, A320, A320neo, A321, and A321neo planes equipped with CFM engines, and AA, DL, AS, G4, and F9 in the U.S. all operate Airbus A320 family aircraft with CFM engines. AS, DL, and F9 also still have orders for Airbus aircraft equipped with CFM engines that haven't been delivered yet.

While I agree that GE/CFM will suffer from lost sales with the 737 MAX grounding, there will still be demand for GE/CFM engines for Airbus aircraft and non-737 Boeing models as GE/CFM will still be producing engines for Airbus aircraft and non-737 Boeing models.

Do engine design problems exist on GE/CFM engines for Airbus planes or non-737 Boeing planes?
 
RickNRoll
Posts: 1728
Joined: Fri Jan 06, 2012 9:30 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 11:32 pm

dakota123 wrote:
Amiga500 wrote:
dakota123 wrote:
Not true. Stick force gradient decreases. It doesn’t go negative.


Dunno if that is directed at me - but reduced (or not enough) control authority does not result in an inversion of stick force.

It is not the elevator stalling that is the problem.


Merely a clarification.

Have a look here, OldAeroGuy explains it well in post 28. viewtopic.php?f=5&t=1418159

(Not directed at you; just generally given all the hysteria that “MCAS is a kludge”. )
It is a kludge. The design is poor, the implementation poor, the testing poor and the documentation poor. The explanation of what it is supposed to do is quite clear.
 
ArgentoSystems
Posts: 303
Joined: Sun Mar 24, 2019 12:05 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 11:42 pm

In my opinion the only proper fix to the plane is going back to drawing board. Any fixes involving disabling MCAS are complete BS. I would not allow it in any less critical application, let alone airplane. If we can disable MCAS and continue flying normally, when why do we need it to begin with?

It especially worrisome that it can lose it during take off, when airplane is deliberately at higher than normal AoA, and the protection is vital. At the same time the invalid input during take off is extremely dangerous.

Now, regarding the redundancy. 3x redundancy with 2 out of 3 voting is nice when you have extremely reliable input to begin with, say on the order 1 incident in a million of flights. In this case 2 out of 3 makes the MTBF so high that realistically we should never see 2 sensors fail.

But we are dealing with 2 fatal incidents in 18 month x 350 planes. And god knows how many similar incidents that did not end in tragedy. That's a crappy track records. 2 out of 3 can't make this acceptably reliable.
 
chance6
Posts: 9
Joined: Wed Mar 13, 2019 12:38 am

Re: B737MAX Grounded Worldwide

Sun Mar 24, 2019 11:56 pm

jplatts wrote:
chance6 wrote:
Not only does Boeing suffer but GE/CFM will suffer from it- grounded aircraft means less servicing which is where engine profits are really made. Airlines cancelling orders will mean profit impacts at the engine makers. So get ready, P&W, you're about to get even busier.


There are actually Airbus A319, A320, A320neo, A321, and A321neo planes equipped with CFM engines, and AA, DL, AS, G4, and F9 in the U.S. all operate Airbus A320 family aircraft with CFM engines. AS, DL, and F9 also still have orders for Airbus aircraft equipped with CFM engines that haven't been delivered yet.

While I agree that GE/CFM will suffer from lost sales with the 737 MAX grounding, there will still be demand for GE/CFM engines for Airbus aircraft and non-737 Boeing models as GE/CFM will still be producing engines for Airbus aircraft and non-737 Boeing models.

Do engine design problems exist on GE/CFM engines for Airbus planes or non-737 Boeing planes?


Yeah that's true, there are many aircraft models supported by the GE/CFM, but the 737 MAX (call it MAX AOA now??) is a major operator of the Leap design. I think the Leap is also an option for Airbus A321 (?)...in any case, the MAX AOA aircraft uses Leap, and Leap only. So it will hurt if this next Fix doesn't do the job. It will be 'terminal', so to speak.

As for engine design problems on other aircraft...ha ha no comment.
 
User avatar
SheikhDjibouti
Posts: 1718
Joined: Sat Sep 30, 2017 4:59 pm

Re: B737MAX Grounded Worldwide

Mon Mar 25, 2019 12:20 am

Chemist wrote:
They didn't "design an unstable aircraft". They modified pyons and added larger engines. Their modeling didn't suggest any adverse effects. Once in flight test, some unexpected pitch behavior was noted ony at high AOAs.
I think Wlederling was particularly taken by your idea that Boeing engineers had not expected a change in pitch behavior. Perhaps they are only qualified to design horse drawn buggies?

Strangely, I seem to have more faith in their design team.
SheikhDjibouti wrote:
I believe their modelling did suggest adverse effects; basically once they had moved the engine forward it was a no-brainer.
Consequently Boeing introduced MCAS with a 0.6deg limit of action.
Then, once in flight test, this was found to be insufficient and they increased it to 2.5deg. (equivalent to maximum deflection in two iterations)

What do you have to support your version?

Chemist wrote:
Well I guess neither of us have those links.
Quelle surprise!

Except... tough luck for you; I found my original link because I actually had one all along and wasn't just inventing facts to suit an agenda.
This Seattle Times article not only supports everything I said above, it also undermines everything you claimed.
https://www.seattletimes.com/business/b ... 0Usl53CXMA

Chemist wrote:
The point being that all the .....accusations don't seem to be founded by any real evidence that I've seen. Lots of accusations without any substance.
You got that bit dead right. :lol:
Unless you can now magic up an article to support your points...... and we all know that isn't going to happen. :scratchchin:
Nothing to see here; move along please.

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