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A3801000
Posts: 562
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 9:38 pm

Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/
 
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gatibosgru
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 9:46 pm

A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/


Well that's gotta burn - regarding the 737-8's H&H performance

Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017. Boeing charged that unfair competition from Bombardier — which beat out Boeing for a large order from Delta Air Lines — threatened its 737-700 and Max 7, the smallest of its upgraded single-aisle jets. By pointing out the limitations of the Max 8, the planemaker sought to preserve market share for the 700 and Max 7.
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PW100
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:02 pm

Carmitage wrote:
Don't forget that the MCAS only used one sensor, so the 20,000 hours MBTF is actually 40,000 hours as the "other" sensor might have failed, but wasn't connected to MCAS on that flight (I think - may well have got that wrong...)


The 20000 hrs MBTF is per sensor (not per aircraft).

The "MCAS AoA" sensor would not possibly know if there was an extra sensor (or even a thousand extra sensors for that matter), it would still remain subject to its 20,000 hrs MBTF.
And of course that 20,000 hrs is an average based on some failure statistics. Actual failure may be earlier, but also (much) later.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
ArgentoSystems
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:05 pm

hivue wrote:
Amiga500 wrote:

The 2nd half of the sentence means it is indeed a stall prevention device and it is a play on word semantics by Boeing (no doubt their lawyer division, which these days seems to benefit from more funding than their engineering division) to pretend otherwise.


You should understand what you're claiming here. You are claiming that if a crew got a perfectly functioning MAX -- no dodgy AoA or anything -- into the remote corner of the envelope MCAS was designed for, and if MCAS activated and provided precisely the opposing stick forces it was designed to, and if the crew stalled the airplane anyway and crashed, then the crash would be partly blamed on MCAS even though it did everything it was supposed to do.

I don't know, maybe my reading comprehension is sub par, but it is also possible that you are bringing the art of reading between the lines to a whole new level. Seriously, the guy said NOTHING of the sort.
 
MSPNWA
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:11 pm

A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):


Sounds like a publication desperate for anything to publish. Nothing about what is quoted in the article in unusual. It's a distraction from the accidents.
 
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PW100
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:18 pm

Revelation wrote:
The NYT article also says:

After the test flights began in early 2016, Boeing pilots found that just before a stall at various speeds, the Max handled less predictably than they wanted. So they suggested using MCAS for those scenarios, too, according to one former employee with direct knowledge of the conversations.

So it was the test pilot community that drove the pitch rate increase into MCAS.

Yet:

Even Boeing test pilots weren’t fully briefed on MCAS.

“Therein lies the issue with the design change: Those pitch rates were never articulated to us,” said one test pilot, Matthew Menza.

Mr. Menza said he looked at documentation he still had and did not see mention of the rate of movement on MCAS. “So they certainly didn’t mention anything about pitch rates to us,” he said, “and I certainly would’ve loved to have known.”

Yet at least part of the test pilot community knew MCAS in detail and knew the pitch rate was increasing, so I'm not sure of the significance of one test pilot saying the documents he had access to did not provide a "full briefing" on "the rate of movement on MCAS". Mr. Menza says he would have wanted to know the info, but that's probably true about all kinds of things. Was there some obligation by Boeing to provide information they did not provide? If so, was this a simple omission, or a deliberate choice to misinform?

I'm asking these questions because without clarification it suggests a fairly sinister allegation, but with clarification it could just be that one person did not get the information others had, or that one person simply wanted more information than the company was obliged to provide.


Perhaps there are two kind of Boeing test pilots: those who do the regular first flights and customer acceptance flights, and those who do the development and certification test flying (the real test pilots). Perhaps the discussion might be missing the distinction between these functions?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
ArgentoSystems
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:33 pm

piedmontf284000 wrote:
I just wanted to post to be the 5000 entry on this thread. Actually in all seriousness, Boeing stated they have compiled 96 test flights totaling 159 hours. They also said that representatives from two-thirds of the 50 airlines that have the Max in their fleets have tested the new software in a simulator. Boeing would like to get their plan to the FAA for approval within the next week or two.

https://www.cnbc.com/2019/04/11/boeing- ... e-fix.html


At this point these numbers are meaningless. I mean, they already completed 100000s of test flights in the past year, so? They have demonstrated complete lack of forethought in dealing with malfunctions, and it is going to take a whole lot more than 100 flights to convince me that there are no more different SNAFUs in their code.
 
multimark
Posts: 466
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:35 pm

gatibosgru wrote:
A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/


Well that's gotta burn - regarding the 737-8's H&H performance

Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017. Boeing charged that unfair competition from Bombardier — which beat out Boeing for a large order from Delta Air Lines — threatened its 737-700 and Max 7, the smallest of its upgraded single-aisle jets. By pointing out the limitations of the Max 8, the planemaker sought to preserve market share for the 700 and Max 7.


Pretty sweet to see Boeing caught in the web of their own bogus trade complaint.
 
ArgentoSystems
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 10:55 pm

XRAYretired wrote:
Not even the Boeing test pilots knew!

https://www.nytimes.com/2019/04/11/busi ... -mcas.html


This is interesting:

from the TFA: "Speed was a defining characteristic for the F.A.A. The agency’s rules require an additional review only if the changes affect how the plane operates in riskier phases of flight: at high speeds and altitudes. "

What? I always thought that take off and landing are the riskier phases of flight.
 
planecane
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 11:00 pm

A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/


Since you found it necessary to post this in both this thread and the ET crash thread, I will reply here as well:


The context of the text in the legal filing wasn't quoted in the article. It basically says that the MAX 7 performs better than the larger variants at hot/high airports. It doesn't mean that the MAX 8 can't or shouldn't be used at those airports, just that there could be payload restrictions.

The 737-700 performs much better than the 737-900ER but that doesn't prevent UAL from using the latter at DEN.

I'm sure there are some airports where the restrictions make it uneconomical to use a 738, 739, 7M8, 7M9 or 7MJ so they will be "not suitable" from an economic standpoint. They are not "not suitable" from a safety standpoint as the article tries to imply.
 
planecane
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 11:06 pm

kalvado wrote:
piedmontf284000 wrote:
I just wanted to post to be the 5000 entry on this thread. Actually in all seriousness, Boeing stated they have compiled 96 test flights totaling 159 hours. They also said that representatives from two-thirds of the 50 airlines that have the Max in their fleets have tested the new software in a simulator. Boeing would like to get their plan to the FAA for approval within the next week or two.

https://www.cnbc.com/2019/04/11/boeing- ... e-fix.html

Great, but they should plan for approval of many regulators. FAA and Boeing would be stained for years if EASA and Chinese CAAC are not be satisfied with FAA review.

There was a reuters (I think) article the other day that stated the foreign agencies were joining the FAA for the review.

I don't think AA pulled June 5th as the date to cancel MAX flights through out of their rear end. I assume that they have been briefed that IF the FAA is satisfied with the software when submitted, the grounding will likely be lifted around that date.
 
A3801000
Posts: 562
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Re: B737MAX Grounded Worldwide

Thu Apr 11, 2019 11:08 pm

planecane wrote:
A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/


Since you found it necessary to post this in both this thread and the ET crash thread, I will reply here as well:


The context of the text in the legal filing wasn't quoted in the article. It basically says that the MAX 7 performs better than the larger variants at hot/high airports. It doesn't mean that the MAX 8 can't or shouldn't be used at those airports, just that there could be payload restrictions.

The 737-700 performs much better than the 737-900ER but that doesn't prevent UAL from using the latter at DEN.

I'm sure there are some airports where the restrictions make it uneconomical to use a 738, 739, 7M8, 7M9 or 7MJ so they will be "not suitable" from an economic standpoint. They are not "not suitable" from a safety standpoint as the article tries to imply.


I find it very relevant in both threads when Boeing itself claims that the Boeing 737 MAX8 “cannot be used at what are referred to as ‘high/hot’ airports.”'

I also think there is a difference between 'not suitable' and 'cannot be used', Boeings own words.

It also says 'The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ..'

'The brief then cites a number of such airports — the names of which are redacted — that the Max 7 can fly that “the 8, 9 and 10 cannot.”

“Larger 737 variants cannot be used at what are referred to has ‘high/hot’ airports,” the brief stated.

So yes, I find it relevant, actually very relevant because those are Boeings own words, in a official, legal document.
 
LDRA
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 12:12 am

piedmontf284000 wrote:
I just wanted to post to be the 5000 entry on this thread. Actually in all seriousness, Boeing stated they have compiled 96 test flights totaling 159 hours. They also said that representatives from two-thirds of the 50 airlines that have the Max in their fleets have tested the new software in a simulator. Boeing would like to get their plan to the FAA for approval within the next week or two.

https://www.cnbc.com/2019/04/11/boeing- ... e-fix.html

Boeing stock went up on that news...
 
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SheikhDjibouti
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 12:36 am

Revelation wrote:
The NYT article also says:
After the test flights began in early 2016, Boeing pilots found that just before a stall at various speeds, the Max handled less predictably than they wanted. So they suggested using MCAS for those scenarios, too, according to one former employee with direct knowledge of the conversations.

So it was the test pilot community that drove the pitch rate increase into MCAS.

We knew that already from three weeks ago. I must admit I thought you were around for that, but I guess you had other fish to fry.

“Therein lies the issue with the design change: Those pitch rates were never articulated to us,” said one test pilot, Matthew Menza.

Revelation wrote:
Yet at least part of the test pilot community knew MCAS in detail and knew the pitch rate was increasing, so I'm not sure of the significance of one test pilot saying the documents he had access to did not provide a "full briefing" on "the rate of movement on MCAS".
Can you identify who amongst the test pilot community "knew MCAS in detail"?
Or, in the absence of specific names a la Menza, a link to a source alluding to this comment (Boeing PR excepted).
I think it is helpful to keep track of what the source of the information is.
That way the reader can decide how meaningful or unmeaningful the information is
See, I know you are very hot on unspecified anonymous sources, so I'm keen to see your response to this. :box:

Likewise, NYT tells us "officials were aware of the changes" without identifying any source for that statement at all, whereas the Seattle Times states the opposite, citing both Boeing and FAA engineers, all of whom requesting anonymity to protect their jobs.

Revelation wrote:
I'm asking these questions because without clarification it suggests a fairly sinister allegation, but with clarification it could just be that one person did not get the information others had, or that one person simply wanted more information than the company was obliged to provide.

Nice spin! :spin: :spin: :spin:
Option A = sinister (evil, menacing, dubious) allegation
Option B = just one single (named) person; i.e. we can throw shade on such testimony
Option C = just one single (named) person being a nuisance and asking awkward questions
Whichever we choose (A, B or C) Boeing somehow comes out of this smelling of roses.

What happened to Option D? The one option actually described in the NYT article?
Option D = Boeing altered MCAS parameters, and then actively and criminally conspired to bury this info deep in a pile of documentation, along with a cheerful "no need to look at all this; your guys have been all over it for months now, nothing to see here..."

Matthew Menza has stepped up and put his name to this,
BOEING TEST PILOT: October 2016 – July 2018
- 737 NG and 737 Max Production Test Pilot Captain.
- 737 Engineering Test Pilot
- Qualified Boeing FA-18E/F Demo/Eval Pilot
- T-33 Target and Chase Pilot
So, not exactly your average Joe.....
Nothing to see here; move along please.
 
trex8
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 12:41 am

Southwest not planning any Max8 flights till august 5! Maybe they know something lots of people here dont, or can't stomach the thought of.

https://www.dallasnews.com/business/sou ... mer-travel
 
planecane
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:13 am

A3801000 wrote:
planecane wrote:
A3801000 wrote:
Has this been discussed at all? Sounds like Boeing shot itself in the foot (again):

'Boeing has called 737 Max 8 “not suitable” for certain high-elevation airports...'

- Before last month’s crash of a flight that began in Ethiopia, Boeing said in a legal document that large, upgraded 737s “cannot be used at what are referred to as ‘high/hot’ airports.”
- At an elevation of 7,657 feet — or more than a mile high — Addis Ababa’s Bole International Airport falls into that category.
- The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ...
- Boeing cited the performance of the 737 Max 8 in a case brought before the U.S. International Trade Commission in 2017.
- “Even if it is B.S., plaintiffs’ lawyers will focus on the quote and put that back to the company to explain it,”

Source: https://www.denverpost.com/2019/04/11/b ... r-airport/


Since you found it necessary to post this in both this thread and the ET crash thread, I will reply here as well:


The context of the text in the legal filing wasn't quoted in the article. It basically says that the MAX 7 performs better than the larger variants at hot/high airports. It doesn't mean that the MAX 8 can't or shouldn't be used at those airports, just that there could be payload restrictions.

The 737-700 performs much better than the 737-900ER but that doesn't prevent UAL from using the latter at DEN.

I'm sure there are some airports where the restrictions make it uneconomical to use a 738, 739, 7M8, 7M9 or 7MJ so they will be "not suitable" from an economic standpoint. They are not "not suitable" from a safety standpoint as the article tries to imply.


I find it very relevant in both threads when Boeing itself claims that the Boeing 737 MAX8 “cannot be used at what are referred to as ‘high/hot’ airports.”'

I also think there is a difference between 'not suitable' and 'cannot be used', Boeings own words.

It also says 'The Ethiopian airport’s altitude hasn’t been cited as a factor in the downing of Flight 302 and likely didn’t cause the crash. But it could have exacerbated the situation ..'

'The brief then cites a number of such airports — the names of which are redacted — that the Max 7 can fly that “the 8, 9 and 10 cannot.”

“Larger 737 variants cannot be used at what are referred to has ‘high/hot’ airports,” the brief stated.

So yes, I find it relevant, actually very relevant because those are Boeings own words, in a official, legal document.


Although we've had this discussion in the other thread, I just thought I'd post here for the benefit of others the actual quote from the legal brief and the quote from the article:

The article says:

"The brief then cites a number of such airports — the names of which are redacted — that the Max 7 can fly that “the 8, 9 and 10 cannot.”

The brief says:

"which allows it to fly certain routes than the 8, 9, and 10 cannot, discussed in greater detail below."

The article left out the word "ROUTES" so that it seems that the the MAX 8, 9 and 10 cannot operate out of those airports.
 
planecane
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:18 am

trex8 wrote:
Southwest not planning any Max8 flights till august 5! Maybe they know something lots of people here dont, or can't stomach the thought of.

https://www.dallasnews.com/business/sou ... mer-travel


Or maybe they know nothing and would rather re-book people now before the other flight options fill up. Also, it will be a much better customer experience to add flights if the MAX is ungrounded prior to 8/5 vs. selling tickets for June and July and then having to cancel flights if it isn't ungrounded in time. AA only suspended MAX flights through 6/5. I'd assume AA and WN have access to the same information from Boeing and the FAA.
 
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SheikhDjibouti
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:31 am

planecane wrote:
Although we've had this discussion in the other thread, I just thought I'd post here for the benefit of others the actual quote from the legal brief and the quote from the article:

The article says:

"The brief then cites a number of such airports — the names of which are redacted — that the Max 7 can fly that “the 8, 9 and 10 cannot.”

The brief says:

"which allows it to fly certain routes than the 8, 9, and 10 cannot, discussed in greater detail below."

The article left out the word "ROUTES" so that it seems that the the MAX 8, 9 and 10 cannot operate out of those airports.

The link to the Denver Times article is above.

What we need from you is a link to "the brief" so that we can all see the original words for ourselves. :yes:

In order to have this discussion we must see the source document, the actual brief. Not some quotes of only a few words

Ring any bells? :scratchchin:
Nothing to see here; move along please.
 
planecane
Posts: 1528
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:34 am

SheikhDjibouti wrote:
planecane wrote:
Although we've had this discussion in the other thread, I just thought I'd post here for the benefit of others the actual quote from the legal brief and the quote from the article:

The article says:

"The brief then cites a number of such airports — the names of which are redacted — that the Max 7 can fly that “the 8, 9 and 10 cannot.”

The brief says:

"which allows it to fly certain routes than the 8, 9, and 10 cannot, discussed in greater detail below."

The article left out the word "ROUTES" so that it seems that the the MAX 8, 9 and 10 cannot operate out of those airports.

The link to the Denver Times article is above.

What we need from you is a link to "the brief" so that we can all see the original words for ourselves. :yes:

In order to have this discussion we must see the source document, the actual brief. Not some quotes of only a few words

Ring any bells? :scratchchin:


It was posted by A3801000 in the other thread. Here it is:
https://leehamnews.com/wp-content/uploads/2017/12/Boeing-Brief-121317.pdf

The chosen quote was to point out how the article presented the quote vs. the full quote.
 
MSPNWA
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:38 am

trex8 wrote:
Southwest not planning any Max8 flights till august 5! Maybe they know something lots of people here dont, or can't stomach the thought of.

https://www.dallasnews.com/business/sou ... mer-travel


Proactive airline operation adjustments covers that story perfectly.

The media has a hard time understanding the difference between an airline schedule and an airline-induced grounding.
 
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SheikhDjibouti
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 1:45 am

In order to have this discussion we must see the source document, the actual brief. Not some quotes of only a few words
Ring any bells? :scratchchin:

It was posted by A3801000 in the other thread. Here it is:
https://leehamnews.com/wp-content/uploads/2017/12/Boeing-Brief-121317.pdf

The chosen quote was to point out how the article presented the quote vs. the full quote.

My bad; I did indeed see the link before, but I didn't follow it up because I wasn't expecting a leehamnews.com link to take me to a 125 page Boeing document.

I have searched for the keyword "routes" and there are 31 entries amongst 125 pages. Thanks…… (don't expect any more feedback anytime soon) :shakehead:
Nothing to see here; move along please.
 
Jetty
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 2:44 am

planecane wrote:
The context of the text in the legal filing wasn't quoted in the article.

The context is Boeing lawyers coming up with bogus claims to defend their cause, with knowledge and approval of Boeing. Every knowledgeable person knows that other variants of the 737 can be used at 'hot and high' airports, but might be limited.

It basically says that the MAX 7 performs better than the larger variants at hot/high airports. It doesn't mean that the MAX 8 can't or shouldn't be used at those airports, just that there could be payload restrictions.

That isn't what Boeing themselves said. Quoting from their own argument:

First, differences in physical characteristics significantly constrain interchangeability between small single-aisle LCA (i.e., the 737-700 and 737 MAX 7) and medium and large single-aisle LCA (i.e., the 737-800, 737 MAX 8, 737-900, 737 MAX 9, 737 MAX 10). As previously mentioned, small single-aisle LCA are uniquely capable of servicing certain “high/hot” airports, whereas medium and large single-aisle LCA are not suitable for certain U.S. airports due a combination of runway length, elevation, temperature, humidity, and other environmental conditions.

Which again shows that Boeing is an immoral company which so for caused the death of 346 persons due to the flawed design of the MAX to avoid $280kk+ in penalties. Not only do they not have a problem misleading the FAA, they don't mind outright lying in legal proceedings either. They deserve everything they get for their despicable behavior and corporate culture.

The 737-700 performs much better than the 737-900ER but that doesn't prevent UAL from using the latter at DEN.

I'm sure there are some airports where the restrictions make it uneconomical to use a 738, 739, 7M8, 7M9 or 7MJ so they will be "not suitable" from an economic standpoint. They are not "not suitable" from a safety standpoint as the article tries to imply.

That isn't just what the article implied, that is what Boeing themselves implied when it suited them.
 
xmp125a
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:54 am

mjoelnir wrote:
xmp125a wrote:
mjoelnir wrote:
It is actually the other way round. If the aircraft switches the sensors each flight, you have to divide the MBTF by two. Having two sensors, but using only one doubles the failure rate.


No. First, MBTF is not affected whether the sensor is used or not, because the signal being read or ignored is immaterial to the failure probability of a sensor. In actuator, possibly yes, in a sensor, no. Switching between sensors simply substitutes one probability function with the other one - but since both of them are the same (same type and age of the sensor) this has no effect on probability of a failure of the whole system. Other way of looking at it is, you have one sensor and your probability is P. Now let's have thousand sensors. The probability of ANY of them failing of course increases (P*100), but now for a failure you have to be using exactly the failed sensor (probability 1/100). So it (roughly?) cancels out.


The probability of one of two separate sensor failing is double of one sensor failing. So if you fly a trip with the broken sensor, but use the unbroken sensor, you will hit the broken sensor on the next trip. If you have no AoA disagree you have no warning that one sensor has failed.


So the only diagnostics available is AoA disagreement? Oh, for chrissake. Then it really is a flying coffin.
 
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Francoflier
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 8:26 am

xmp125a wrote:
So the only diagnostics available is AoA disagreement? Oh, for chrissake. Then it really is a flying coffin.


I sincerely hope that's not what they'll come up with.

Manufacturers have moved away from the very basic and arithmetic '2 out of 3' method (which the MCAS doesn't even have...) and gone to more sophisticated software based signal trustworthiness analysis based on predictive algorithm and data from the myriad other sensors around the aircraft.

Why Boeing didn't come up with such a solution in the first place, or why they even opted to step backwards to the archaic 'no-backup' system they implemented, we might never know, but I'm sure they can now come up with something that belongs in the 21st century...
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
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PixelFlight
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 8:31 am

planecane wrote:
PixelFlight wrote:
xmp125a wrote:
And given the gravity of the situation Boeing is faced with, this will not just disappear from the news. There will be final report on LionAir, which will stoke the interest again, and there will be final report on Ethiopian in about a year or so. And in meantime there will be a lot of reminders about the whole MAX fiasco when Boeing is due to report quarterly results, perhaps even adjust production schedule again, etc.

I suspect that there will be very difficult meetings trying to evaluate the risk of reusing the MAX on commercial flights before the JT610 and ET302 final reports are published.


Why? It's pretty clear exactly what led to the crashes and what must be done to prevent MCAS from being able to do that in the future. Does it really matter if a bird strike or a magic unicorn caused the AoA sensor failure to the point that the final reports are necessary?

It is also known (whether the pilots actually tried or not) that manually trimming nose up while holding back pressure to counteract far out of trim nose down is nearly impossible and that training and documentation on the "roller coaster" procedure from the 737-100 should be reintroduced.

Because the final reports will each contain a (probably long) list of recommendations. I am not convinced that all aspects of those accidents have been addressed already. The last few weeks have raised an insane number of new design and certification issues that the public didn't know before. So the question is what could still be found by the investigators ? The certification authorities (the FAA in particular) have there credibility seriously affected and it's not so clear to me if there will take the risk to releasing the MAX again without knowing in detail what the investigators of both crashes will publish in there recommendations.

The main problem for the certification authorities is that there very own procedures will be affected by the final reports recommendations. How can there credibly release the MAX with procedures that will be targeted by the MAX crashes final reports ? If there find a way to manage that risk, there certainly need to communicate it properly with the public.
: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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JetBuddy
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 10:36 am

Like someone else mentioned earlier in this thread - I wonder if it would be possible to add a small aerodynamic feature to the nacelles, pylons or wing root to negate the stall characteristics at certain AoA.

Maybe a small fin to break the airflow over the engine nacelles and pylons, so that it doesn't generate any meaningful lift anywhere in the flight envelope. It could be a very cheap fix.
 
jollo
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 10:40 am

Francoflier wrote:
xmp125a wrote:
So the only diagnostics available is AoA disagreement? Oh, for chrissake. Then it really is a flying coffin.


I sincerely hope that's not what they'll come up with.

Manufacturers have moved away from the very basic and arithmetic '2 out of 3' method (which the MCAS doesn't even have...) and gone to more sophisticated software based signal trustworthiness analysis based on predictive algorithm and data from the myriad other sensors around the aircraft.

Why Boeing didn't come up with such a solution in the first place, or why they even opted to step backwards to the archaic 'no-backup' system they implemented, we might never know, but I'm sure they can now come up with something that belongs in the 21st century...


I'm not so sure: I'm not aware of any commercial aviation-certified ADIRU (or equivalent air data processing equipment) actually incorporating the advanced data sanitation methods you describe. Don't misunderstand me, IMO that would be a useful, safety-enhancing and overdue advancement (as would be solid state - laser - aero sensors) but I'm afraid that's still a few years away. Besides, I doubt effective real-time predictive filters could run in software on a MAX "as is": I have trouble imagining the FCC's having enough spare CPU and RAM resources available. I guess that some custom DSP hardware would be needed at the very least.

Anyway, I would be happy to be proved wrong, and I completely agree that this should be the target for a net-generation, clean sheet design. For anyone interested, Google "fault detection and isolation" and "active fault tolerant control systems" for references.

Let's say that even adding simple logic to disable automations on a sensor disagree condition (state of the art in the 60', already surpassed since the 80') would be a step ahead from a control system vulnerable to catastrophic runaways on a single sensor fault.
 
FluidFlow
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 11:17 am

JetBuddy wrote:
Like someone else mentioned earlier in this thread - I wonder if it would be possible to add a small aerodynamic feature to the nacelles, pylons or wing root to negate the stall characteristics at certain AoA.

Maybe a small fin to break the airflow over the engine nacelles and pylons, so that it doesn't generate any meaningful lift anywhere in the flight envelope. It could be a very cheap fix.


This fix will not work, unfortunately. The airflow that creates the additional lift at high AoA would have to be partially diverted under the wing. To achieve this the fin would have to be big (along the whole nacelle due to engine placement on the wing). Another poster had a nice picture with the small fin and how the flow goes over the wing and optimally the fin would have to be angled so during level flight it would not horizontal.

This big fin would change the aerodynamics of the nacelle during level flight and increase drag and therefore fuel consumption. So all the additional lift and rotation has to be equaled out by the stabilizer.
 
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PixelFlight
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 11:37 am

jollo wrote:
Francoflier wrote:
xmp125a wrote:
So the only diagnostics available is AoA disagreement? Oh, for chrissake. Then it really is a flying coffin.


I sincerely hope that's not what they'll come up with.

Manufacturers have moved away from the very basic and arithmetic '2 out of 3' method (which the MCAS doesn't even have...) and gone to more sophisticated software based signal trustworthiness analysis based on predictive algorithm and data from the myriad other sensors around the aircraft.

Why Boeing didn't come up with such a solution in the first place, or why they even opted to step backwards to the archaic 'no-backup' system they implemented, we might never know, but I'm sure they can now come up with something that belongs in the 21st century...


I'm not so sure: I'm not aware of any commercial aviation-certified ADIRU (or equivalent air data processing equipment) actually incorporating the advanced data sanitation methods you describe. Don't misunderstand me, IMO that would be a useful, safety-enhancing and overdue advancement (as would be solid state - laser - aero sensors) but I'm afraid that's still a few years away. Besides, I doubt effective real-time predictive filters could run in software on a MAX "as is": I have trouble imagining the FCC's having enough spare CPU and RAM resources available. I guess that some custom DSP hardware would be needed at the very least.

Anyway, I would be happy to be proved wrong, and I completely agree that this should be the target for a net-generation, clean sheet design. For anyone interested, Google "fault detection and isolation" and "active fault tolerant control systems" for references.

Let's say that even adding simple logic to disable automations on a sensor disagree condition (state of the art in the 60', already surpassed since the 80') would be a step ahead from a control system vulnerable to catastrophic runaways on a single sensor fault.

I fully support "Francoflier" on this: flight dynamic predictive sensors filter is the future for commercial civil aviation. The fact that no commercial aviation-certified ADIRU with predictive sensors filter is actually available is an industry width issue that must be addressed with enough priority to be part of the new designs.

As for the CPU and RAM resources, remember that the predictive filter was developed for the Apollo mission and was flying on the dinosaurs processors that was available a half century ago. Limited resources will limit the precision of the prediction, but still give something useful. Even an old ADIRU will be able to do something. The FCC is implemented with similar hardware and already contains some predictive filter for the autopilot functions.
: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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PW100
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 11:56 am

A3801000 wrote:
...
“Larger 737 variants cannot be used at what are referred to has ‘high/hot’ airports,” the brief stated.

So yes, I find it relevant, actually very relevant because those are Boeings own words, in a official, legal document.


Not suited, can be meant as technically not suited, or commercially not (or less) suited. Very big difference.

I can see how a uninformed journo, stirring up the pot can't (or doesn't want to) see the difference. I'd expect the average Anet user to be better informed.

Runway performance of ET302 does not seem to be any factor in this accident.
In fact, I don't think that aircraft performance in the sense of thrust, pressure altitude etc is in any meaningful way at discussion here, let alone a suspected contributory factor.

Therefore I see this article, and subsequently posts around that, as noise distracting us from the root cause.
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

Fri Apr 12, 2019 12:09 pm

Jetty wrote:
First, differences in physical characteristics significantly constrain interchangeability between small single-aisle LCA (i.e., the 737-700 and 737 MAX 7) and medium and large single-aisle LCA (i.e., the 737-800, 737 MAX 8, 737-900, 737 MAX 9, 737 MAX 10). As previously mentioned, small single-aisle LCA are uniquely capable of servicing certain “high/hot” airports, whereas medium and large single-aisle LCA are not suitable for certain U.S. airports due a combination of runway length, elevation, temperature, humidity, and other environmental conditions.

Which again shows that Boeing is an immoral company which so for caused the death of 346 persons due to the flawed design of the MAX to avoid $280kk+ in penalties. Not only do they not have a problem misleading the FAA, they don't mind outright lying in legal proceedings either. They deserve everything they get for their despicable behavior and corporate culture.


No, it (again) shows that those who conclude that Being is an immoral company, can't distinguish between "technically not suited", and "commercially not suited".

Even the worst performing aircraft can take off from ADD airport. No question about that. The question is not if it is (technically) possible, the question is if it is commercially viable to do so with the technical/operational limitations in mind for the applicable route.

Do you/we have any indications that the doomed flight was somehow overweight, or underpowered for the actual pressure altitude and temperature?
Or should we now be suggesting the AoA may have went inop due to tail strike, as a result of MAX-8 not being "suited" for the ambient conditions . . . . ?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
WIederling
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 3:55 pm

FluidFlow wrote:
The airflow that creates the additional lift at high AoA would have to be partially diverted under the wing. To achieve this the fin would have to be big (along the whole nacelle due to engine placement on the wing).


Turning an upward flow down is what we call "lift". :-)
Murphy is an optimist
 
kalvado
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 4:10 pm

PW100 wrote:
Jetty wrote:
First, differences in physical characteristics significantly constrain interchangeability between small single-aisle LCA (i.e., the 737-700 and 737 MAX 7) and medium and large single-aisle LCA (i.e., the 737-800, 737 MAX 8, 737-900, 737 MAX 9, 737 MAX 10). As previously mentioned, small single-aisle LCA are uniquely capable of servicing certain “high/hot” airports, whereas medium and large single-aisle LCA are not suitable for certain U.S. airports due a combination of runway length, elevation, temperature, humidity, and other environmental conditions.

Which again shows that Boeing is an immoral company which so for caused the death of 346 persons due to the flawed design of the MAX to avoid $280kk+ in penalties. Not only do they not have a problem misleading the FAA, they don't mind outright lying in legal proceedings either. They deserve everything they get for their despicable behavior and corporate culture.


No, it (again) shows that those who conclude that Being is an immoral company, can't distinguish between "technically not suited", and "commercially not suited".

Even the worst performing aircraft can take off from ADD airport. No question about that. The question is not if it is (technically) possible, the question is if it is commercially viable to do so with the technical/operational limitations in mind for the applicable route.

Do you/we have any indications that the doomed flight was somehow overweight, or underpowered for the actual pressure altitude and temperature?
Or should we now be suggesting the AoA may have went inop due to tail strike, as a result of MAX-8 not being "suited" for the ambient conditions . . . . ?

Playing devil's advocate:
Yes, hot and high and mountainous could play a role in a crash as takeoff configuration was somewhat off normal - long runway, high thrust, low flaps setting. High thrust throughout the flight and low cleanup despite recommendations to preserve configuration in order to avoid terrain - leading to little if any time for pilots to correct situation before MCAS kicked in - could be a contributing factor to a blowback of stabilizer, hence a contributing factor. If a frame with a higher performance, whatever it means, would be used - the outcome may be different.
Not sure if I buy that myself, but the question is if the judge would buy that.
 
FluidFlow
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 5:00 pm

WIederling wrote:
FluidFlow wrote:
The airflow that creates the additional lift at high AoA would have to be partially diverted under the wing. To achieve this the fin would have to be big (along the whole nacelle due to engine placement on the wing).


Turning an upward flow down is what we call "lift". :-)


You are right there if it is just a flat metal fin. If you design the fin like a spoiler to generate lift downwards at high AoA that stalls towards the end so instead of connecting with the other air package and flows over the wing it will flow underneath. This will increase lift at the wing and reduce it at the nacelle. You shift it.

This shit comes at a cost of corse and this is a lot of drag. Therefore my „solution“ ist just a theory. Its a nogo for a plane as it wont be economical.

Sorry I am a doing theoretical work for a living. There is always a solution to everything as long as you can trade one thing for another. ;-)
 
SimonL
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 6:25 pm

Im bit curious on how they found out that a 2.5 degree nose down trim would make the MAX feels exactly like a NG. The effect of the trim is greatly dependent on speed so the way MCAS works it is only in a narrow corner of the envelope that it will work as intended. Given the fact that they use such a large deflection suggest that it is pretty much only tested on an unaccelerated stall at low speed. Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..
 
morrisond
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:04 pm

PW100 wrote:
Jetty wrote:
First, differences in physical characteristics significantly constrain interchangeability between small single-aisle LCA (i.e., the 737-700 and 737 MAX 7) and medium and large single-aisle LCA (i.e., the 737-800, 737 MAX 8, 737-900, 737 MAX 9, 737 MAX 10). As previously mentioned, small single-aisle LCA are uniquely capable of servicing certain “high/hot” airports, whereas medium and large single-aisle LCA are not suitable for certain U.S. airports due a combination of runway length, elevation, temperature, humidity, and other environmental conditions.

Which again shows that Boeing is an immoral company which so for caused the death of 346 persons due to the flawed design of the MAX to avoid $280kk+ in penalties. Not only do they not have a problem misleading the FAA, they don't mind outright lying in legal proceedings either. They deserve everything they get for their despicable behavior and corporate culture.


No, it (again) shows that those who conclude that Being is an immoral company, can't distinguish between "technically not suited", and "commercially not suited".

Even the worst performing aircraft can take off from ADD airport. No question about that. The question is not if it is (technically) possible, the question is if it is commercially viable to do so with the technical/operational limitations in mind for the applicable route.

Do you/we have any indications that the doomed flight was somehow overweight, or underpowered for the actual pressure altitude and temperature?
Or should we now be suggesting the AoA may have went inop due to tail strike, as a result of MAX-8 not being "suited" for the ambient conditions . . . . ?


It didn't have much problems accelerating past Vmo while climbing - that doesn't seem too underpowered to me.

Now I get it - the MAX's problem is that it was Overpowered - they should never have installed such high thrust engines to allow the aircraft to accelerate past Vmo in climb as we can't assume the Pilots know to pull back the thrust levers.

That above quote about the 738/9/10 not being suited for Hot and High airports is ridiculous (about as ridiculous as my sentence just above - Sorry). Can you load it as close to MTOW as one of the smaller variants at a high airport on a hot day - probably not depending on the performance tables but that applies to almost any series of commercial airplanes including A320, A330 and A350 series.

Or is it now Airbus and Boeing's fault that you can't load all of there Commerical aircaft to MTOW no matter the altitude of the Airport, the length of the runway or the temperature and successfully make it into the air?
 
IADFCO
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:15 pm

FluidFlow wrote:
WIederling wrote:
FluidFlow wrote:
The airflow that creates the additional lift at high AoA would have to be partially diverted under the wing. To achieve this the fin would have to be big (along the whole nacelle due to engine placement on the wing).


Turning an upward flow down is what we call "lift". :-)


You are right there if it is just a flat metal fin. If you design the fin like a spoiler to generate lift downwards at high AoA that stalls towards the end so instead of connecting with the other air package and flows over the wing it will flow underneath. This will increase lift at the wing and reduce it at the nacelle. You shift it.

This shit comes at a cost of corse and this is a lot of drag. Therefore my „solution“ ist just a theory. Its a nogo for a plane as it wont be economical.

Sorry I am a doing theoretical work for a living. There is always a solution to everything as long as you can trade one thing for another. ;-)


Maybe some sort of small active spoiler on the nacelle, just big enough to trip the boundary layer, that would pop out at some predetermined angle of attack – but then we would need a sensor to determine when to make it pop out, and we would be back to square one.

Personally, I have full confidence that the Boeing flight control engineers can take care of the problem from the FCS side (I know some of them professionally, although not on the commercial airplane side). It's on their management, and now the FAA, that I have zero trust at this point.
 
hivue
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:32 pm

SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
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PixelFlight
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:51 pm

hivue wrote:
SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.
: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:
 
kalvado
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:54 pm

PixelFlight wrote:
hivue wrote:
SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.

There was a mention about backup all-optical AoA & true airpeed system tested by EASA. It is in development, so maybe some day...
 
morrisond
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 7:57 pm

PixelFlight wrote:
hivue wrote:
SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.


How about better training for the ultimate back-up system - The Pilots!
 
kalvado
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 8:13 pm

morrisond wrote:
PixelFlight wrote:
hivue wrote:

In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.


How about better training for the ultimate back-up system - The Pilots!

Well, if it comes to that... how about hiring real engineers? And hiring even more to do real failure tree analysis? You know, paying engineers instead of using money for campaign contributions?
Humans are expected to make mistakes. And that has to be taken into account. If precise pilot action is essential to keep situation like AOA failure in check, plane is not certifiable. There has to be at least a second chance for the human - if the system is designed properly. But that is probably too big of a concept for some to digest, and Boeing is learning it the hard way.
 
XRAYretired
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 8:50 pm

PixelFlight wrote:
hivue wrote:
SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.

Do you work for PixelFlight dynamic predictive sensors filters Inc? If so, you deserve that bonus this year.

Ray
 
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dennypayne
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 8:55 pm

planecane wrote:
trex8 wrote:
Southwest not planning any Max8 flights till august 5! Maybe they know something lots of people here dont, or can't stomach the thought of.

https://www.dallasnews.com/business/sou ... mer-travel


Or maybe they know nothing and would rather re-book people now before the other flight options fill up. Also, it will be a much better customer experience to add flights if the MAX is ungrounded prior to 8/5 vs. selling tickets for June and July and then having to cancel flights if it isn't ungrounded in time. AA only suspended MAX flights through 6/5. I'd assume AA and WN have access to the same information from Boeing and the FAA.


FWIW I booked a WN flight a few days ago for June 9 that was scheduled to be on a MAX. So far, the schedule remains the same in my Trip Details page, but it doesn't list a type like it did on the reservation.

EDIT: I started a new reservation just to see, and it is now showing a 738. So they've managed to shuffle that one around without affecting the schedule it seems.
A300/310/319/320/321/332/333/343/380 AN24/28/38/148 ARJ AT6/7 B190
B717/722/732/3/4/5/7/8/9 741/744/752/753/762/763/764/772/773/788/789
CR1/2/7/9 D8S D93/4/5 DHC2/3/7/8 D28/38 EMB/EM2/ER3/D/4/E70/75/90
F50/100 J31 L10 L4T M11/80/87/90 SF3 SU9 TU3/TU5 YK2
 
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aerolimani
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Re: B737MAX Grounded Worldwide

Fri Apr 12, 2019 9:32 pm

PixelFlight wrote:
hivue wrote:
SimonL wrote:
Im not sure i want to know what would happen in a "AF447"-type situation where the AP disconnects and MCAS kicks in at cruising speed and altitude. The nose down will be pretty violent..


In the case of AF447 the FO -- the human -- pitched the airplane up and stalled it. If the A330 had had something like MCAS that could operate in degraded law the outcome might have been a whole lot better.

The A330 have that kind of protection but like for the MCAS it don't work as expected if the sensors failed. There exists others accidents or incidents where failed sensors played a significant role. The civil aircraft industry need to evolve to address this issue, because in addition to the expected failure rate and some human handling error, birds collision and extreme whether will never be under human control. Adding more sensors is a good thing up to a point but will not address the common failure case that have been observed. An another approach is required, like flight dynamic predictive sensors filters.

Actually, the aircraft did respond as expected. As a result of sensor loss, the plane reverted to alternate law 2, where certain flight envelope protections are no longer in place. It was the pilots who did not react as expected.

As to the original question, http://www.b737.org.uk/mcas.htm describes the following, regarding MCAS operation:

The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers.
 
planecane
Posts: 1528
Joined: Thu Feb 09, 2017 4:58 pm

Re: B737MAX Grounded Worldwide

Sat Apr 13, 2019 12:10 am

dennypayne wrote:
planecane wrote:
trex8 wrote:
Southwest not planning any Max8 flights till august 5! Maybe they know something lots of people here dont, or can't stomach the thought of.

https://www.dallasnews.com/business/sou ... mer-travel


Or maybe they know nothing and would rather re-book people now before the other flight options fill up. Also, it will be a much better customer experience to add flights if the MAX is ungrounded prior to 8/5 vs. selling tickets for June and July and then having to cancel flights if it isn't ungrounded in time. AA only suspended MAX flights through 6/5. I'd assume AA and WN have access to the same information from Boeing and the FAA.


FWIW I booked a WN flight a few days ago for June 9 that was scheduled to be on a MAX. So far, the schedule remains the same in my Trip Details page, but it doesn't list a type like it did on the reservation.

EDIT: I started a new reservation just to see, and it is now showing a 738. So they've managed to shuffle that one around without affecting the schedule it seems.


I know this is off topic, but where do you see aircraft type in the WN trip details? I have 3 upcoming trips and checked all of them on the website and there is no aircraft type for any of them.
 
MSPNWA
Posts: 3695
Joined: Thu Apr 23, 2009 2:48 am

Re: B737MAX Grounded Worldwide

Sat Apr 13, 2019 12:32 am

kalvado wrote:
Well, if it comes to that... how about hiring real engineers? And hiring even more to do real failure tree analysis? You know, paying engineers instead of using money for campaign contributions?
Humans are expected to make mistakes. And that has to be taken into account. If precise pilot action is essential to keep situation like AOA failure in check, plane is not certifiable. There has to be at least a second chance for the human - if the system is designed properly. But that is probably too big of a concept for some to digest, and Boeing is learning it the hard way.


So the solution to mitigate human mistakes is human engineering? Hmm.

You're right, humans are expected to make mistakes. That's why we only put special people in the cockpit of airliners. Those people have the knowledge and training to minimize their own mistakes and cover for others' mistakes. When that safety feature breaks down, as it apparently did in the two crashes, it needs to be addressed as well. Personally I don't find pilot mistakes or airline mistakes any more acceptable than design or engineering mistakes.
 
kalvado
Posts: 2580
Joined: Wed Mar 01, 2006 4:29 am

Re: B737MAX Grounded Worldwide

Sat Apr 13, 2019 1:34 am

MSPNWA wrote:
kalvado wrote:
Well, if it comes to that... how about hiring real engineers? And hiring even more to do real failure tree analysis? You know, paying engineers instead of using money for campaign contributions?
Humans are expected to make mistakes. And that has to be taken into account. If precise pilot action is essential to keep situation like AOA failure in check, plane is not certifiable. There has to be at least a second chance for the human - if the system is designed properly. But that is probably too big of a concept for some to digest, and Boeing is learning it the hard way.


So the solution to mitigate human mistakes is human engineering? Hmm.

You're right, humans are expected to make mistakes. That's why we only put special people in the cockpit of airliners. Those people have the knowledge and training to minimize their own mistakes and cover for others' mistakes. When that safety feature breaks down, as it apparently did in the two crashes, it needs to be addressed as well. Personally I don't find pilot mistakes or airline mistakes any more acceptable than design or engineering mistakes.

Too bad you don't understand simple concepts.
People do make mistakes when they have little time. Some plane makers still have to graduate to that, but the nuclear industry was dealing with that since 60s and 70s.
Here is the crash course on the topic:
If a person is trained to press button #5 in a row of 10 under certain conditions, and does it often enough, their chances of making mistake are 1 in 1000. If it is once in a long while unusual thing, the error rate can go up to 1:10.
That is why certain scenarios are trained over and over again, although they rarely happen. And that is why creating high workload situation is bad - especially if it is not pre-trained scenario.

Unlike nuclear station operators, engineers rarely have seconds to react. They enjoy ability to go for peer review, testing, simulations and what not.
Designing things under
morrisond wrote:
How about better training for the ultimate back-up system - The Pilots!

means someone needs a promotion to the janitorial service team.

I hope you guys don't talk from first-hand industrial experience, as you're really degrading Boeing to the level of third world repair shop.
 
User avatar
dennypayne
Posts: 297
Joined: Tue Mar 13, 2012 3:38 am

Re: B737MAX Grounded Worldwide

Sat Apr 13, 2019 3:41 am

planecane wrote:
dennypayne wrote:
FWIW I booked a WN flight a few days ago for June 9 that was scheduled to be on a MAX. So far, the schedule remains the same in my Trip Details page, but it doesn't list a type like it did on the reservation.

EDIT: I started a new reservation just to see, and it is now showing a 738. So they've managed to shuffle that one around without affecting the schedule it seems.


I know this is off topic, but where do you see aircraft type in the WN trip details? I have 3 upcoming trips and checked all of them on the website and there is no aircraft type for any of them.


I've only been able to see it during the booking process, if you click on the flight number for the details, the type shows up there. But you're right, once it's booked, the type doesn't seem to show up anymore in your reservation.
A300/310/319/320/321/332/333/343/380 AN24/28/38/148 ARJ AT6/7 B190
B717/722/732/3/4/5/7/8/9 741/744/752/753/762/763/764/772/773/788/789
CR1/2/7/9 D8S D93/4/5 DHC2/3/7/8 D28/38 EMB/EM2/ER3/D/4/E70/75/90
F50/100 J31 L10 L4T M11/80/87/90 SF3 SU9 TU3/TU5 YK2
 
many321
Posts: 313
Joined: Sat Mar 11, 2017 6:15 am

Re: B737MAX Grounded Worldwide

Sat Apr 13, 2019 3:53 am

Interesting. Though perhaps its a scare tactic to get Boeing back into shape.

https://www.seattletimes.com/business/b ... ing-fleet/

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