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FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 10:34 am

PixelFlight wrote:
uta999 wrote:
Can someone please explain what a MAX 8 without MCAS would fly like under normal operations? and are we getting near to a situation where it is dropped altogether, in favour of just a new type rating.

At least we known now that even the EASA didn't have a satisfactory response on that question yet... Expecting some news on that question after the full week test flight.


Things here could go really bad for Boeing. Up to now it is speculated that aft CoG and certain areas in the flight envelope lead to aircraft behavior that is not certifiable with current regulations if MCAS is not active/present.

If EASA then tells Boeing to reduce the aft CoG limits to comply, or limit the flight envelope you can operate in, the aircraft might be certified and cleared to commercially fly again but all aircraft already sold will have a reduced performance, compared to what they were sold as. This could lead to more compensations needed and also a reduced value of the aircraft, especially if the limitations implemented actually reduce the overall economical benefit of the MAX over other models.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 10:38 am

asdf wrote:
if there really is a strong missbehavior in flight attidutes because of the large engine nacceles, mounted at a very unusual position ... and the "stick feeling thing" is only a excuse to hush it up ... well, thats going to be dirty

there is no way to fix it

Ok, correct me if I am wrong here, but if we go by this trend of thought we are saying that the pilots who have been flying the MAX have been seeing MCAS version 1.0 activated throughout the flight profiles and thought it was STS? In all the leaks and opinions posted since they stated they knew nothing about MCAS I do not recall seeing any pilots saying that the trim wheels in the MAX were much more active than in the NG, which is what MCAS would be doing if the a/c is inherently unstable with those larger engines and the nacelles (If I understand the MCAS function correctly).

If MCAS is required for flight and more than just meeting a FAR requirement, Boeing would have known that, the test pilots would have known that, and the documentation surrounding MCAS would have had to be more extensive since it would be a replacement of the STS system.

I also wonder why we are now being told there are two sets of EASA requirements, the ones we are now advised was put forward in April, and the other specific items that were disclosed during the June MCAS version XX testing when bit flip was introduced.
The way the information has come out, we can be forgiven for assuming that Boeing ignored the June items and the regulators walked out the meeting, now we have to question whether the items that caused the walk were those from April which put the FAA and a larger part of its process under the gun, did the FAA advise Boeing to leave those items out?

As they say in conspiracies, oh what a tangled web we weave when first we practice to deceive.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 10:56 am

FluidFlow wrote:
PixelFlight wrote:
uta999 wrote:
Can someone please explain what a MAX 8 without MCAS would fly like under normal operations? and are we getting near to a situation where it is dropped altogether, in favour of just a new type rating.

At least we known now that even the EASA didn't have a satisfactory response on that question yet... Expecting some news on that question after the full week test flight.


Things here could go really bad for Boeing. Up to now it is speculated that aft CoG and certain areas in the flight envelope lead to aircraft behavior that is not certifiable with current regulations if MCAS is not active/present.

If EASA then tells Boeing to reduce the aft CoG limits to comply, or limit the flight envelope you can operate in, the aircraft might be certified and cleared to commercially fly again but all aircraft already sold will have a reduced performance, compared to what they were sold as. This could lead to more compensations needed and also a reduced value of the aircraft, especially if the limitations implemented actually reduce the overall economical benefit of the MAX over other models.

Will see. The situation is a bit strange, because in order to make the certification conformance testing, both Boeing and the FAA should already have the response that that question. Why there didn't share a satisfactory response to the EASA on that question is the most intriguing aspect to me.
: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:
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 11:05 am

par13del wrote:
asdf wrote:
if there really is a strong missbehavior in flight attidutes because of the large engine nacceles, mounted at a very unusual position ... and the "stick feeling thing" is only a excuse to hush it up ... well, thats going to be dirty
there is no way to fix it

Ok, correct me if I am wrong here, but if we go by this trend of thought we are saying that the pilots who have been flying the MAX have been seeing MCAS version 1.0 activated throughout the flight profiles and thought it was STS? In all the leaks and opinions posted since they stated they knew nothing about MCAS I do not recall seeing any pilots saying that the trim wheels in the MAX were much more active than in the NG, which is what MCAS would be doing if the a/c is inherently unstable with those larger engines and the nacelles (If I understand the MCAS function correctly).


EASA wants a flight test with MCAS failed inactive during a high speed wind up turn to stall

The fear seems to be that the 737 MAX will be uncontrollable at a high speed wind up turn.
Such a maneuver is very rare in practice, so there are no reports from 737MAX pilots that the trim wheel would be activated more often. Even if there were such activations, they may not have been recognized (STS).

If you wanted to follow this theory, MCAS would be nothing more than a cover up.
A manufacturer can not tell the regulator "our new models have been given highly critical flight behavior based on modified engines at the edge of the flight envelope, so we are building a augmentaion system that should prevent the pilots from entering those maneuvering areas."
But you can say "The Stick feeling does not comply with the requierments. We are addding a augmentation system, dont care about, it is not important, nothing can happen, we even doesnt need to confuse the pilots with this information ..."
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 11:57 am

2175301 wrote:
"With the 737 MAX we are a bit worried ... because we don't see the normal unanimity among international regulators that should be the case," Alexandre de Juniac, IATA director general, told reporters ahead of a summit in Chicago.

"We see a discrepancy that's detrimental to the industry," he added, urging regulators to make any changes to the single certification process "collectively." ]

He should be prepared for some "detriment", since FAA still says:

“We aren’t going to comment on specific details about ongoing discussions,” the FAA said in a statement. “The FAA has a transparent and collaborative relationship with other civil aviation authorities as we continue our review of changes to software on the Boeing 737 MAX … Each government will make its own decision to return the aircraft to service based on a thorough safety assessment.”

Ref: https://www.seattletimes.com/business/b ... to-flight/

ST also quotes an anonymous "safety official within FAA" as saying:

He said that the software and system changes Boeing has proposed have been all but agreed upon within the FAA and that only the level of pilot training that will be required remains undecided.

Meanwhile, EASA's position is that there is “still no appropriate response to Angle of Attack integrity issues”.

Seems EASA is not buying that the "cosmic ray" fix provides appropriate protection for AoA disagree faults.

Rock, meet hard place.

This may become the aviation industry's Brexit, since both sides are staking out hard line positions with neither willing or even able to budge since both sides are putting their reputations on the line.
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bennett123
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 12:15 pm

Am I the only one who finds people using BA for Boeing Aircraft and British Airways confusing?.
 
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SomebodyInTLS
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 12:37 pm

bennett123 wrote:
Am I the only one who finds people using BA for Boeing Aircraft and British Airways confusing?.


You're not the only one. Despite having lurked here for literally decades, I also do double-takes on that on a regular basis. Wish people would realise that stock ticker labels don't belong on a site already too full of aerospace acronyms and abbreviations.
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
freakyrat
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 1:24 pm

From This mornings Dallas Morning News.
Southwest is optimistic.

https://www.dallasnews.com/business/loc ... nksgiving/
 
frmrCapCadet
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 1:30 pm

One could hope that both FAA and EASA would be more concerned with how the pilot could fly the plane in extreme circumstances, given that pilots have training to do that. Rather, MCAS was designed to meet some artificial regulations about just how much feed back the stick will have.

It is an interesting question about how the MAX could fly on a very high AOL while making a sharp turn. It is not unreasonable to ask for that to be done. But at the same time no "silly walks" about stick feedback preventing the pilot from flying the plane.
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TC957
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 1:55 pm

From the BBC news - whatever the FAA decides EASA won't accept :
https://www.bbc.co.uk/news/business-49591363
 
Olddog
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 1:59 pm

freakyrat wrote:
From This mornings Dallas Morning News.
Southwest is optimistic.

https://www.dallasnews.com/business/loc ... nksgiving/


SW has showed multiple times they are not the best informed....
Sentence from Belgian PM at press conference forbidden due to new rules
 
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JetBuddy
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 2:29 pm

Olddog wrote:
freakyrat wrote:
From This mornings Dallas Morning News.
Southwest is optimistic.

https://www.dallasnews.com/business/loc ... nksgiving/


SW has showed multiple times they are not the best informed....


In a scenario where the FAA "ungrounds" the aircraft, and EASA is reluctant - I think Southwest would start flying the MAX again.

Some customers would probably be sceptical. Others might not. Interesting times ahead.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 2:55 pm

asdf wrote:
par13del wrote:
asdf wrote:
if there really is a strong missbehavior in flight attidutes because of the large engine nacceles, mounted at a very unusual position ... and the "stick feeling thing" is only a excuse to hush it up ... well, thats going to be dirty
there is no way to fix it

Ok, correct me if I am wrong here, but if we go by this trend of thought we are saying that the pilots who have been flying the MAX have been seeing MCAS version 1.0 activated throughout the flight profiles and thought it was STS? In all the leaks and opinions posted since they stated they knew nothing about MCAS I do not recall seeing any pilots saying that the trim wheels in the MAX were much more active than in the NG, which is what MCAS would be doing if the a/c is inherently unstable with those larger engines and the nacelles (If I understand the MCAS function correctly).


EASA wants a flight test with MCAS failed inactive during a high speed wind up turn to stall

The fear seems to be that the 737 MAX will be uncontrollable at a high speed wind up turn.
Such a maneuver is very rare in practice, so there are no reports from 737MAX pilots that the trim wheel would be activated more often. Even if there were such activations, they may not have been recognized (STS).

If you wanted to follow this theory, MCAS would be nothing more than a cover up.
A manufacturer can not tell the regulator "our new models have been given highly critical flight behavior based on modified engines at the edge of the flight envelope, so we are building a augmentaion system that should prevent the pilots from entering those maneuvering areas."
But you can say "The Stick feeling does not comply with the requierments. We are addding a augmentation system, dont care about, it is not important, nothing can happen, we even doesnt need to confuse the pilots with this information ..."


The question is, what does the EASA consider acceptable test results? Obviously, with MCAS off, the MAX can't pass the certification test. If it could, then MCAS wouldn't have been created. If that is the EASA's requirement, then they can never clear the MAX to return to service.

If their requirement is simply that the aircraft is controllable and that, if it enters a stall, it can be recovered then this should not be an issue as long as Boeing has been truthful about the reason for MCAS.

The aircraft is demonstrated to fly fine and not fall out of the sky under normal flight conditions simply based on the fact that JT043 flew for over an hour with no MCAS and using the manual trim wheel. I assume that if there were controllability issues, that would have been documented in the preliminary report on JT610.
 
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ACCS300
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 3:01 pm

Curious to know what Canada will do once the FAA clears the MAX to fly. My guess is that they ill wait until EASA ungrounds considering AC Max's previously flew to KEF, DUB and LHR.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 3:05 pm

TC957 wrote:
From the BBC news - whatever the FAA decides EASA won't accept :
https://www.bbc.co.uk/news/business-49591363

I really dont know why anyone thinks EASA intention to certify on the basis of independent review is news?

https://www.reuters.com/article/us-ethi ... SKCN1R01XR
19-March-2019
'Patrick Ky, executive director of the European Union Aviation Safety Agency (EASA), said EASA would look “very deeply” at Boeing’s software updates and study all the failure modes of the Boeing 737 MAX - the airplane type grounded in Europe last week after one of the models crashed in Ethiopia on March 10 killing 157 people.
“I can guarantee to you that on our side we will not allow the aircraft to fly if we have not found acceptable answers to all our questions on that,” Ky told the European Parliament transport committee.
He added that EU decisions would be made irrespective of what the U.S. watchdog, the Federal Aviation Administration (FAA), decide on the case.'

Ray
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 3:46 pm

planecane wrote:
If their requirement is simply that the aircraft is controllable and that, if it enters a stall, it can be recovered then this should not be an issue as long as Boeing has been truthful about the reason for MCAS.

I think this is the point
and this is not far fetched
the question is why hasent boeing given a possibility to proof that since beginning of april
this is not a question of MCAS 2.0 development
this is simply a testflight with the MAX
without MCAS

planecane wrote:
The question is, what does the EASA consider acceptable test results? Obviously, with MCAS off, the MAX can't pass the certification test.
If it could, then MCAS wouldn't have been created. If that is the EASA's requirement, then they can never clear the MAX to return to service.

i dont think so
but if the plane needs MCAS to be within certification parameters
a cause of MCAS must not allow the aircraft to fall into a condition not provided for by the certification.
Usually this is ensured by two existing systems, which are adjusted in the event of a mismatch with a third such standby system
To see the flightdeck crew as "redundancy" in such an event is ..... at least ...... exotic.
 
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Momo1435
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 3:48 pm

I think that there's a very big chance that both FAA and EASA will still clear the MAX around the same time. Just because the EASA will not simply delegate the decission made by the FAA it doesn't mean that they won't consider each others assessments when coming to their own final decissions.

It's also not like that the EASA is working against Boeing and the MAX or even the FAA. They are not doing this to delay the certification, they just want to be certain that the MAX is safe to fly. The best way to do that is to pro active towards Boeing, from the BBC article is very clear that they are working close together to make this happen.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 3:55 pm

MSPNWA wrote:
PW100 wrote:
They are/were not SIGNING OFF another's work. They are/were ACCEPTING another's work. Completely different thing.


They're the same thing! Two different words don't automatically create two different meanings.

Another real-life example: Let's say I "accept" a shipment of goods from a supplier. I sign off on the delivery with barely a once-over, or worse, sight-unseen, completely taking their word for it because they've been reliable. Am I resolved of responsibility to my firm if that shipment is wrong? Of course not. I didn't make the mistake in loading the wrong shipment, but I am absolutely responsible for accepting it as-is. We both made a mistake. You can debate "grades" of mistakes, but you can't deny both made a mistake.

The idea that the EASA who:

-doesn't know the details of the MAX certification
-made a mistake by accepting the certification of the FAA based on agreements and prior trust

= being the ultimate authority for ungrounding the MAX is logically incongruent.


Two different words don't automatically create two different meanings
Correct. You need to know the context. In this case the context is very clear, and there is clearly a very different meaning to the two words.

The shipment goods supplier is a very poor comparison. The thing is that EASA and FAA have an agreement, which stipulates basically what the difference is between SIGNING OFF and ACCEPTING another's work. It lots of harmonization of regulations to and took twenty years of top level discussions to reach that agreement.

This is not about "we both made a mistake", it's about having checks and balances, controls and processes in place to catch such mistakes. And clearly, on the FAA side they have not worked.

The BASA agreement basically arranges that there is no longer duplication of efforts. A certification effort is a big process. It starts already at the design process, and finishes 5 – 10 years later with Type Certificate. Nobody (not FAA, not EASA, and certainly not Boeing) has anything to gain in duplicating such huge efforts. Hence the BASA agreement.

Again, it has nothing to do with EASA not doing its due diligence, because that is exactly what such agreement is intended for.
You would be correct if there were no such agreement, then EASA had a much higher level of due diligence.

If you want to throw out that agreement, then Boeing better be prepared that EASA will take another two - three years to re-certify the MAX, and each following new model. 77X is next in line.
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bob75013
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:00 pm

freakyrat wrote:
From This mornings Dallas Morning News.
Southwest is optimistic.

https://www.dallasnews.com/business/loc ... nksgiving/


WN is probably taking a que from Boeing, which yeasterday said it still expects MAXs to be flying by early 4Q19
 
AirBoat
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:00 pm

just my 2c
engineers are not poets, they write in simple English so that their fellow workers can understand them properly.
so mcas means: helping the aircraft to pitch up or down. there is nothing in there about stick force. so is this a hidden active control system?
as for never needing the manual trim wheel. well the rules say you need a backup. saying you may never need it is not logical.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:03 pm

uta999 wrote:
Can someone please explain what a MAX 8 without MCAS would fly like under normal operations? and are we getting near to a situation where it is dropped altogether, in favour of just a new type rating.


Many have been asking that, and there is no real answer, other than some words to the effect that is not really needed, and a (good) pilot won't be needing it. But the supporting data from flight testing to prove such statements are not in the public domain. I have no doubt that Boeing will not be sharing such specific flight test details - for various reasons, most of them very good and understandable.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:11 pm

frmrCapCadet wrote:
But at the same time no "silly walks" about stick feedback preventing the pilot from flying the plane.


I am no pilot or aeronautical engineer, but my understanding is that stick force requirements are in the regulations so that pilots can recognize a seriously out of trim situation and fix it by re-trimming before things get out of hand.
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:27 pm

asdf wrote:
I think this is the point
and this is not far fetched
the question is why hasent boeing given a possibility to proof that since beginning of april
this is not a question of MCAS 2.0 development
this is simply a testflight with the MAX
without MCAS

If they were working on a fix for MCAS why would that not be relevant for the testing?
The systems in the a/c are integrated, MCAS is not stand alone, if they want to go and take a MCAS ver 1.0 a/c and test it what would be the point if Boeing is in the process of changing it? Easier to wait until the fix is done since MCAS version 1.0 will never fly again.

However, since this is from April, why did EASA not include that in the testing that was done in June when the MCAS version 2.0 fix was submitted, the FAA did add the bit flip, was that related? Based on the addition of the bit flip, we do know that the FAA could have included additional test items, a test with MCAS 2.0 off should have been doable.

We sure that is not what happened which led to the bit flip issue and because the information was not initially released we believe it is something new?
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:27 pm

planecane wrote:
The aircraft is demonstrated to fly fine and not fall out of the sky under normal flight conditions simply based on the fact that JT043 flew for over an hour with no MCAS and using the manual trim wheel. I assume that if there were controllability issues, that would have been documented in the preliminary report on JT610.


I'd expect the (any) regulator to explore a somewhat larger flight envelope that that utilized by JT043.

Perhaps EASA want to do the flight testing to better understand aerodynamic characteristics of the basic airframe, sans MCAS. And how MCAS affects the stability margins and stick force gradients. This would be needed to determine the authority level deemed necessary for MCAS, and to determine any possible flight envelope restrictions when MCAS becomes disabled.
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WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:28 pm

frmrCapCadet wrote:
One could hope that both FAA and EASA would be more concerned with how the pilot could fly the plane in extreme circumstances, given that pilots have training to do that. Rather, MCAS was designed to meet some artificial regulations about just how much feed back the stick will have.

It is an interesting question about how the MAX could fly on a very high AOL while making a sharp turn. It is not unreasonable to ask for that to be done. But at the same time no "silly walks" about stick feedback preventing the pilot from flying the plane.


1: Those "artificial regulations" is one part of what has made planes exceptionally save.
They are not like one of these speed limits that appear to solely exist for creating game for speed cameras.

2: High mass and high g is what increases demand on AoA, AoA being strongly related to creating lift.
If you do a tight turn the demand for lift increases further.
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:29 pm

Olddog wrote:
freakyrat wrote:
From This mornings Dallas Morning News.
Southwest is optimistic.

https://www.dallasnews.com/business/loc ... nksgiving/


SW has showed multiple times they are not the best informed....

It's not just WN that has optimistic things to say.

WN:

"We're assuming that we will have the go-ahead to return the Max to service by, call it the beginning to mid-November," Southwest Chief Financial Officer Tammy Romo said Wednesday at a Cowen & Co. transportation conference in Boston.

UA:

"We've told them that from our perspective, nothing prevents us from physically taking as many aircraft as they can deliver to us," (Gerry Laderman, the airline's finance chief) said at the conference. "They're going to be the constraint on that."


AS:
"We're confident in the Max," said CFO Brandon Pedersen. "It's going to be a great airplane for us."
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asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:38 pm

par13del wrote:
asdf wrote:
I think this is the point
and this is not far fetched
the question is why hasent boeing given a possibility to proof that since beginning of april
this is not a question of MCAS 2.0 development
this is simply a testflight with the MAX
without MCAS

If they were working on a fix for MCAS why would that not be relevant for the testing?


EASA want to see how the plane behaves WITHOUT any augmentation
probably to deside how important a backup of the augmentation system is and if - maybe- you can leave it to the crew if a sensor fails
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:43 pm

asdf wrote:
par13del wrote:
asdf wrote:
EASA want to see how the plane behaves WITHOUT any augmentation
probably to deside how important a backup of the augmentation system is and if - maybe- you can leave it to the crew if a sensor fails

EASA is fully aware that the a/c is not certifiable by the FAA without the augmentation, so the point there is what.....to have two different set's of certification requirements which are incompatible with each other?

I do believe there are MAX a/c in Europe, I am certain they could get approvals for a test flight, the question would be how to turn off MCAS.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:46 pm

I should have added, based on what I read about MCAS and the requirements, it has to be automatic, not something the pilots activate to ensure stick feel....the termination or limitation of MCAS is a verison 2.0 revision, not available with version 1.0 in the April time frame of the request.
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:47 pm

par13del wrote:
asdf wrote:
par13del wrote:

EASA is fully aware that the a/c is not certifiable by the FAA without the augmentation, so the point there is what.....


i suspect the question is as simple as:
- can the MAX be flown by a average flight deck crew
- without SIM training
- with high AOA in a sharp turn (but within the flight envelope)
- without augmentation
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 4:52 pm

Point is, EASA wants to see first hand "natural" behavior of the airplane during wind-up-turn and at higher AoA. This will then easily reflect criticality of MCAS failure....very simple.

It is pointless that some users here are debating and advocating necessity of WUT demonstrations and high AoA....
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:14 pm

asdf wrote:
i suspect the question is as simple as:
- can the MAX be flown by a average flight deck crew

We know 300+ were delivered and in operation by average flight crew, not just the professionals in the developed world.
asdf wrote:
- without SIM training

Methinks most at WN were without SIM training, and since the simulators are just being delivered.....
asdf wrote:
- with high AOA in a sharp turn (but within the flight envelope)
- without augmentation

I will leave the other two alone, you already have my thoughts on those.
 
frmrCapCadet
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:37 pm

hivue wrote:
frmrCapCadet wrote:
But at the same time no "silly walks" about stick feedback preventing the pilot from flying the plane.


I am no pilot or aeronautical engineer, but my understanding is that stick force requirements are in the regulations so that pilots can recognize a seriously out of trim situation and fix it by re-trimming before things get out of hand.


Neither am I, but repeatedly it seems to have been explained that one regulation requires the stick feed back is always linear. If I understand, and I think I do, because of certain flight characteristics the stick feed back lightens at high AOA when the plane is also making a sharp turn. The feed back is what MCAS is addressing. I also have been led to understand that under those conditions other alarms likely are going off, stall and speed warnings. Perhaps an expert could offer a better explanation. But to me it seemed a little bit of a Rube Goldberg system which went tragically wrong.
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frmrCapCadet
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:42 pm

PW100 wrote:
planecane wrote:
The aircraft is demonstrated to fly fine and not fall out of the sky under normal flight conditions simply based on the fact that JT043 flew for over an hour with no MCAS and using the manual trim wheel. I assume that if there were controllability issues, that would have been documented in the preliminary report on JT610.


I'd expect the (any) regulator to explore a somewhat larger flight envelope that that utilized by JT043.

Perhaps EASA want to do the flight testing to better understand aerodynamic characteristics of the basic airframe, sans MCAS. And how MCAS affects the stability margins and stick force gradients. This would be needed to determine the authority level deemed necessary for MCAS, and to determine any possible flight envelope restrictions when MCAS becomes disabled.


Again my non-expert but read all threads and other authorities, IIRC: A MAX is never suppose to get into that particular flight envelope (very high AOA and making a sharp turn at the same time), the exceptions would be some sort of extreme flying to avoid a collision or some such. I think I also read that 737s in general and pilots have never experienced that part of the flight envelope. Corrections to my understanding are welcome.
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sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:47 pm

par13del wrote:
asdf wrote:
...the question would be how to turn off MCAS.


AOA disagree turns off MCAS. And assuming an AOA data issue - either by a failed sensor, improperly installed sensor, failed ADIRU, or improperly installed ADIRU - occurs every 5 months during takeoff, it should be reasonable to look at the remote possibility of this occurring during a high speed stall, or approach to stall.

We already know that in a dual channel design, the side of the aircraft with the working sensor would still be presenting valid airspeed. IIRC, the FO in both crashes had valid airspeed.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
ODwyerPW
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:50 pm

par13del wrote:
asdf wrote:
par13del wrote:

EASA is fully aware that the a/c is not certifiable by the FAA without the augmentation, so the point there is what.....to have two different set's of certification requirements which are incompatible with each other?

I do believe there are MAX a/c in Europe, I am certain they could get approvals for a test flight, the question would be how to turn off MCAS.


par13del wrote:
I should have added, based on what I read about MCAS and the requirements, it has to be automatic, not something the pilots activate to ensure stick feel....the termination or limitation of MCAS is a verison 2.0 revision, not available with version 1.0 in the April time frame of the request.


par13del wrote:
asdf wrote:
i suspect the question is as simple as:
- can the MAX be flown by a average flight deck crew

We know 300+ were delivered and in operation by average flight crew, not just the professionals in the developed world.
asdf wrote:
- without SIM training

Methinks most at WN were without SIM training, and since the simulators are just being delivered.....
asdf wrote:
- with high AOA in a sharp turn (but within the flight envelope)
- without augmentation

I will leave the other two alone, you already have my thoughts on those.


I really appreciate the contributions made by the two of you. I fly on 737's almost exclusively (sans the occasional ERJ/CRJ) and I'd like to know that. If MCAS is disabled and the pilots have to make aggressive manuevers (e.g. said high AOA and sharpt turn), how do the 7MAX,8MAX and 9MAX respond? Have there been those types of scenarios proven in flight tests? Was that information shared? Is Boeing willing to demonstrate that for EASA? Did they demonstrate that for FAA? If MCAS is really absolutely nothing more than a stick feel augmenation, then this should/would/could have been conducted. To me, this gets down to whether or not MCAS was needed for more... I'm hoping the answer is no, it's not.... but EASA wants to see that demonstrated... I don't blame them... As a passenger, I'd like to know we've been told the truth about this. Trust, but verify.
learning never stops.
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:51 pm

sgrow787 wrote:
par13del wrote:
asdf wrote:
...the question would be how to turn off MCAS.


AOA disagree turns off MCAS. And assuming an AOA data issue - either by a failed sensor, improperly installed sensor, failed ADIRU, or improperly installed ADIRU - occurs every 5 months during takeoff, it should be reasonable to look at the remote possibility of this occurring during a high speed stall, or approach to stall.

We already know that in a dual channel design, the side of the aircraft with the working sensor would still be presenting valid airspeed. IIRC, the FO in both crashes had valid airspeed.


wrong quoted
i never asked for that
did i?
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:51 pm

frmrCapCadet wrote:
PW100 wrote:
planecane wrote:
The aircraft is demonstrated to fly fine and not fall out of the sky under normal flight conditions simply based on the fact that JT043 flew for over an hour with no MCAS and using the manual trim wheel. I assume that if there were controllability issues, that would have been documented in the preliminary report on JT610.


I'd expect the (any) regulator to explore a somewhat larger flight envelope that that utilized by JT043.

Perhaps EASA want to do the flight testing to better understand aerodynamic characteristics of the basic airframe, sans MCAS. And how MCAS affects the stability margins and stick force gradients. This would be needed to determine the authority level deemed necessary for MCAS, and to determine any possible flight envelope restrictions when MCAS becomes disabled.


Again my non-expert but read all threads and other authorities, IIRC: A MAX is never suppose to get into that particular flight envelope (very high AOA and making a sharp turn at the same time), the exceptions would be some sort of extreme flying to avoid a collision or some such. I think I also read that 737s in general and pilots have never experienced that part of the flight envelope. Corrections to my understanding are welcome.


Its not at all question of airplane getting there. It is question of knowing where natural stall occurs and backdriving from there as that point is the point which determines everything, your ref speeds and it can be easily said that it is the point which drives performance as margin from that point is taken for everything else. Now up until that point stall characteristics and approach to stall are very precisely described in certification regulations.

In essence, allowing Boeing to not maintain that margin and characteristics would be extremely unfair towards other and it would provide "free performance" at others expense and at the expense of safety margin. How critical this is is exactly why MCAS was invented to begin with.....except 737 legacy architecture doesn't support smartness MCAS requires....

Hope this helps....
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:54 pm

And I have to clarify few more things. It is not a question of aggresive maneuvers.....more it boils down to speeds at which someone might execute tight turn to final while he is slowing down, or for example windshear encounters, but above all it is margin from that point (stall) which is fixed and drive performance....
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 5:56 pm

frmrCapCadet wrote:
PW100 wrote:
planecane wrote:
The aircraft is demonstrated to fly fine and not fall out of the sky under normal flight conditions simply based on the fact that JT043 flew for over an hour with no MCAS and using the manual trim wheel. I assume that if there were controllability issues, that would have been documented in the preliminary report on JT610.


I'd expect the (any) regulator to explore a somewhat larger flight envelope that that utilized by JT043.

Perhaps EASA want to do the flight testing to better understand aerodynamic characteristics of the basic airframe, sans MCAS. And how MCAS affects the stability margins and stick force gradients. This would be needed to determine the authority level deemed necessary for MCAS, and to determine any possible flight envelope restrictions when MCAS becomes disabled.


Again my non-expert but read all threads and other authorities, IIRC: A MAX is never suppose to get into that particular flight envelope (very high AOA and making a sharp turn at the same time).....


does that really matter if it is "supposed to"?

if the MAx does not show a catastrophical flight attitude at such manoevers (within flight envelope!) why does it need months to arrange a f***ing testflight for EASA without that complete augmentation stuff to make it shure
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 6:02 pm

ExperimentalFTE wrote:
And I have to clarify few more things. It is not a question of aggresive maneuvers.....more it boils down to speeds at which someone might execute tight turn to final while he is slowing down, or for example windshear encounters, but above all it is margin from that point (stall) which is fixed and drive performance....


this would be manoevers that are not that rare at all

what is the problem for boeing not to accept that simple testflight?
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 6:06 pm

sgrow787 wrote:
AOA disagree turns off MCAS.

Now it does in version 2.0, the convo started about EASA requesting the test flight without MCAS in April, so version 1.0.
 
sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 6:39 pm

par13del wrote:
sgrow787 wrote:
AOA disagree turns off MCAS.

Now it does in version 2.0, the convo started about EASA requesting the test flight without MCAS in April, so version 1.0.


Point taken.
But EASAs requests are still there in the latest slides report, so MCAS 1.0 should be irrelevant at this point.

Three ways to cutoff MCAS 1.0:
(1) Extend flaps
(2) Go to autopilot
(3) Flip both aisle Cutout switches

Only (3) applies to high speed maneuver.

But Im not a pilot. (getting tired of having to say that)

5 ways to cutoff MCAS 2.0:
(1)(2)(3) same for v1.0
(4) Duck tape the left AOA to +75 deg before takeoff
(5) Install a modified build into the left FCC that mimics a recurring bitflip on the MCAS Engaged flag. Then takeoff.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 6:59 pm

par13del wrote:
sgrow787 wrote:
AOA disagree turns off MCAS.

Now it does in version 2.0, the convo started about EASA requesting the test flight without MCAS in April, so version 1.0.

'EASA requirements for flight/Simulator evaluation communicated on May 22. 70 test points requested to be evaluated, covering: 
Normal operations (identification of MCAS operation)
Abnormal operations (AoA failures, stabiliser runaway, MCAS inoperative,…)
Simulators evaluation performed in June and July.'

The test flight programme will be required to be performed on a certification submission configured aircraft. There is little point in EASA requiring tests prior to submission since they would then need to be repeated.

The intended certification configuration is yet to be submitted. You can expect the tests to be performed in the October timeframe (assuming no further problems are identified).

Ray
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 7:11 pm

ExperimentalFTE wrote:
And I have to clarify few more things. It is not a question of aggresive maneuvers.....more it boils down to speeds at which someone might execute tight turn to final while he is slowing down, or for example windshear encounters, but above all it is margin from that point (stall) which is fixed and drive performance....


Are flaps deployed under that scenario?
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 7:21 pm

planecane wrote:
ExperimentalFTE wrote:
And I have to clarify few more things. It is not a question of aggresive maneuvers.....more it boils down to speeds at which someone might execute tight turn to final while he is slowing down, or for example windshear encounters, but above all it is margin from that point (stall) which is fixed and drive performance....


Are flaps deployed under that scenario?


Depands, they certainly will be in some cases but might not in the others...
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 7:37 pm

MCAS is used for flaps up only.
 
slider
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 7:41 pm

I'm sticking with my spring break 2020 estimate....
 
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zkojq
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 7:43 pm

planecane wrote:

I respect your opinion and your post has definitely been a wakeup call as far as expectations of who is sitting at the controls. I guess I had hoped that at least one of the two pilots would be above average in skill and quick thinking/problem solving ability.

Mate if you don't want people to accuse you of being a troll, you really shouldn't go making statements like that.
First to fly the 787-9
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 05, 2019 9:29 pm

sgrow787 wrote:
Three ways to cutoff MCAS 1.0:
(1) Extend flaps
(2) Go to autopilot
(3) Flip both aisle Cutout switches

Only (3) applies to high speed maneuver.

But Im not a pilot. (getting tired of having to say that)

5 ways to cutoff MCAS 2.0:
(1)(2)(3) same for v1.0
(4) Duck tape the left AOA to +75 deg before takeoff
(5) Install a modified build into the left FCC that mimics a recurring bitflip on the MCAS Engaged flag. Then takeoff.

:scratchchin: :mischievous:
(3) or any of the cutout switches (there are connected in serial).
(4) or the right AoA (any too high differences disable MCAS).
(6) Move the yoke in the opposite pitch (MCAS V2 grant elevator authority).
: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:

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