jollo
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 4:42 pm

Revelation wrote:
The screw up was many poor decisions by engineers with regard to MCAS. We read that these happened largely because of management pressure, but when push comes to shove it is a part of an engineer's job to resist management pressure and produce safe designs and implementations to the best of one's abilities.


Been there, done that. Often the best an engineer can realistically get to is archiving an e-mail trail documenting how he unequivocally raised and motivated his concerns and the management's overriding decisions. That or looking for a new job. But when you're already working for the best shop in town, for good money and plush benefits, and the next best, or third best, employment alternative means relocating the family, and you can never be 100% sure that this particular corner-cutting decision will blow up - the company could get lucky after all... I can tell you it's not an easy decision. Whistle-blower protection for design decisions - well, not if you're interested in your future employment prospects.

Revelation wrote:
Some of the things we've seen, such as accepting a single AoA input without sanitizing the data, multiple/endless MCAS activation, etc do not pass muster even if under large amounts of management pressure.


I feel I should explain my particular sore spot with pilots not being able to disable MCAS 1.0: it's not an obsession for terminolgy. It's because when you are designing an automation system with potentially catastrophic failure modes (single input, unlimited authority controllers are a textbook case), the absolute minimally acceptable design standards calls for both input sanitation and a big, red switch enabling the operator to quickly disable the controller (not the actuators) while retaining all manual controls to deal with the impending mess (plus enough training to give him/her at least a fighting chance). MCAS 1.0 - designed by the best of the best - had neither, and it makes me professionally ashamed.

The final, bitter irony is that if only Boeing had left NG's stab trim cut out switches design unchanged, the "A/P" cut out switch would already have been an effective way to properly disable MCAS (together with A/P and STS, both of which are not very useful when dealing with a MCAS runaway) while retaining full manual electric trim control.
Last edited by jollo on Wed Sep 11, 2019 4:49 pm, edited 2 times in total.
 
bob75013
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 4:43 pm

kalvado wrote:
DenverTed wrote:
Six months after the grounding and 20 years after the NG has been flying with two AOA sensors, EASA decides they need three? Maybe they can make a case for a slow retrofit, but this does not seem like a legitimate reason to delay the return to service.

In case you missed it, two planes crashed because of AoA failures...


I think you meant "two planes crashed because of single AoA failures"
 
IADFCO
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 4:51 pm

XRAYretired wrote:
WIederling wrote:
XRAYretired wrote:
I think whether or not you call it anti stall is moot (and may well be debated in court).


A rose by any other name :-)

I do balk at the high speed thingy.
This backstory appears to be more of a detraction than anything else.

Higher speeds provide more lift from the same AoA.
The region most susceptible to being over "AoAd" is just after you
have retracted flaps into clean config. i.e. lowish speed in the clean config domain.

Assume you mean airspeed, then the calculated AOA trigger value will no doubt be lower at lower airspeeds.

Ray


IIRC in one of the early NYT articles there was a passing reference to "transonic" somewhere between nacelle, pylon, and wing. This might imply shock-induced separation, which would complicate the aerodynamic picture. In other words, at high speed it would not be just a matter of AoA.
 
Eyad89
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 5:02 pm

DenverTed wrote:
Six months after the grounding and 20 years after the NG has been flying with two AOA sensors, EASA decides they need three? Maybe they can make a case for a slow retrofit, but this does not seem like a legitimate reason to delay the return to service.


You know, industry standards tend to evolve and change through time. And this isn’t just true in the aviation industry. What was a common practice 20 years ago in the industry I work in (oil and gas) could simply be unacceptable in 2019.
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 5:31 pm

Revelation wrote:
Hyperbole.

Marketing is not as ignorant of engineering issues as you suggest. They would have largely known the challenges of doing a clean sheet NSA in 2011. They may not have known issues related to MAX and nacelle lift but they would have known there were going to be engine integration issues and that engineering might need time and resources to resolve them.

The system counts on engineers (especially delegated representatives!) to not sign off on unsafe designs even with heavy management pressure to do so.

To me this is where the FBI/DoJ probe needs to be centered: who signed off, and why, are there any smoking guns?


You are underestimating lot of very smart engineers in Boeing.... Are you trying to tell me that this hasn't been seen during wind tunnel testing while they were counting drag counts and trying to come up with performance guarantees for customers? Are you telling me that noone did approach to stall test point in wind tunnel as part of validation of the model? So what exactly was marketing selling? Well only numbers they liked from that....

Oh wait lets reference another textbook saga in program management. KC-46 tanker....everything engineering told management was dismissed or deferred as "we will take it on risk"!. And what is the top speed of KC-46 and when does buffet kick in?

Cheers
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 5:37 pm

ExperimentalFTE wrote:

You are underestimating lot of very smart engineers in Boeing.... Are you trying to tell me that this hasn't been seen during wind tunnel testing while they were counting drag counts and trying to come up with performance guarantees for customers? Are you telling me that noone did approach to stall test point in wind tunnel as part of validation of the model? So what exactly was marketing selling? Well only numbers they liked from that....

THis is exactly the published story - yes, unexpected airflow behavior.
And I don't know anyone from Boeing, but if they are on par with other hi-tech companies - yes, most their engineers are not extremely dumb - but...
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:09 pm

ExperimentalFTE wrote:
You are underestimating lot of very smart engineers in Boeing.... Are you trying to tell me that this hasn't been seen during wind tunnel testing while they were counting drag counts and trying to come up with performance guarantees for customers? Are you telling me that noone did approach to stall test point in wind tunnel as part of validation of the model? So what exactly was marketing selling? Well only numbers they liked from that....

Wait, I was the one making the argument that marketing is more well informed than you suggest.

If we believe Seattle Times, yes, the nacelle lift issue was known early on via wind tunnel tests.

If Boeing works like any big company I know of, marketing heard of it soon thereafter, either directly or via the rumor network.

Marketing people's whole job is to trade in information, and in my experience they know a lot more about what is going on project wide than the engineers in the trenches.

I would also expect that they were being told that engineering could find a solution and it only was an issue for a small part of the flight envelope that was rarely entered.

This is the standard line we still hear to this day.

It seems your main point is that the nacelle lift issue is unacceptable and unsolvable, and I think you are wrong.

Time will tell which of us is right.

BTW if you read this site you will find a former Boeing engineer suggesting that the MAX engine install has less drag than the NG one, due to solutions found via modelling not available during the NG days.

I'm not sure why you seem to be suggesting that there was selective use of the data.
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WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:11 pm

Revelation wrote:
The fact that the MCAS design was totally botched does not undo the market verdict that the MAX was the preferred product.


Preferred what other product?
* A320
* NSA
or a
* MAX with sane MCAS. :-)
( note: customers were not informed about the deficiencies though Boeing knew about the circumstances they came about.
Murphy is an optimist
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:17 pm

Agrajag wrote:
morrisond wrote:
Agrajag wrote:


Exactly so.


OK - so then the new standard is that if an Engineer or an Organization makes a mistake they are going to Jail?

Does that apply to FAA employees as well for lack of oversight or Airplane mechanics neglecting to replace a component that results in a crash or for pilots that fail to follow a published procedure?

Good luck on getting Good/Smart people into the industry if that is the standard people on here are believing that the Aviation industry should be held too.



Morrisond, i have been following your comments on here since the beginning of these Max threads. Well worth a glance back to March and April for anyone interested. At least being wrong all the time is a form of consistency. Well done.

I appreciate that you are not a lawyer but im sure you can use google. A clear explanation of Criminal Negligence can be found there.


So I screwed up the definition of Criminal Negligence?

I think if you look back objectively and when the final analysis comes in I'll be proven right on a lot of things.

I find it amusing how the definitive description of MCAS from the bash Boeing side comes from a sight I first posted (737.org) but was repeatedly attacked for.

A-Net would be a lot better place without personal attacks.

Please familiarize yourself with the forum rules:

a. Respecting Other Users
1. Please respect the opinions of others and choose your words wisely. Each user has their own point of view, and these views must be respected.
2. Please word all criticism, whether of another user's opinion, a photograph, crew member, a political topic, etc., in a constructive manner. Criticism which serves no purpose other than to incite or insult other members will be deleted and your account possibly suspended.
 
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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:25 pm

Revelation wrote:
ExperimentalFTE wrote:
You are underestimating lot of very smart engineers in Boeing.... Are you trying to tell me that this hasn't been seen during wind tunnel testing while they were counting drag counts and trying to come up with performance guarantees for customers? Are you telling me that noone did approach to stall test point in wind tunnel as part of validation of the model? So what exactly was marketing selling? Well only numbers they liked from that....

Wait, I was the one making the argument that marketing is more well informed than you suggest.

If we believe Seattle Times, yes, the nacelle lift issue was known early on via wind tunnel tests.

If Boeing works like any big company I know of, marketing heard of it soon thereafter, either directly or via the rumor network.

Marketing people's whole job is to trade in information, and in my experience they know a lot more about what is going on project wide than the engineers in the trenches.

I would also expect that they were being told that engineering could find a solution and it only was an issue for a small part of the flight envelope that was rarely entered.

This is the standard line we still hear to this day.

It seems your main point is that the nacelle lift issue is unacceptable and unsolvable, and I think you are wrong.

Time will tell which of us is right.

BTW if you read this site you will find a former Boeing engineer suggesting that the MAX engine install has less drag than the NG one, due to solutions found via modelling not available during the NG days.

I'm not sure why you seem to be suggesting that there was selective use of the data.


Oh dear, no, not suggesting that nacelle lift is unsolvable...but I am suggesting that philosophy of solving it (as is) is completely unacceptable....

Let me remind you that even FBW aircraft are stalled in direct mode for stall characteristics certification which has a very strict set of requirements...regardless of the fact that aircraft will not be there and that there is a stall protection in normal mode...

So question is....can MAX pass basic stall characteristics certification (with pitch up) without MCAS input....I believe answer is obvious. Not to mention the fact that MCAS doesn't have nearly integrity of the FBW system but in essence does same functions in this area.....

Beer!
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:31 pm

WIederling wrote:
Revelation wrote:
The fact that the MCAS design was totally botched does not undo the market verdict that the MAX was the preferred product.


Preferred what other product?
* A320
* NSA
or a
* MAX with sane MCAS. :-)
( note: customers were not informed about the deficiencies though Boeing knew about the circumstances they came about.

The context was what Boeing was offering, and my points make it clear the market preferred MAX to NSA.

Sorry that I seem to have triggered the instinctive reflex to defend the divinity of Airbus at every bend in the road.

Maybe we should discuss what Airbus knew about Pratt's failings while marketing the NEO, but I bet people would complain that doing so would be unfair.

Yet it's open season on Boeing, so fire away!
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:44 pm

Revelation wrote:
The context was what Boeing was offering, and my points make it clear the market preferred MAX to NSA.

Sorry that I seem to have triggered the instinctive reflex to defend the divinity of Airbus at every bend in the road.

Maybe we should discuss what Airbus knew about Pratt's failings while marketing the NEO, but I bet people would complain that doing so would be unfair.

Yet it's open season on Boeing, so fire away!

Not sure why the general point related to MAX versus NSA is being thrown in with the poor design of MCAS, even now, persons are saying that a clean sheet narrow body will not appear until the engine tech gives a larger improvement than what the current NEO engines have provided.

On the Airbus and Pratt issue, my bet is that the response will be .....no NEO's have crashed.
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:44 pm

Revelation wrote:
Yet it's open season on Boeing, so fire away!


No need self destruct has been initiated.

NSA was a mirage not a product.
Murphy is an optimist
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 6:56 pm

ExperimentalFTE wrote:
Oh dear, no, not suggesting that nacelle lift is unsolvable...but I am suggesting that philosophy of solving it (as is) is completely unacceptable....

Seems like it is about to be accepted by FAA despite the high visibility created by the bad publicity, which would undermine your statement about complete unacceptability.

ExperimentalFTE wrote:
Let me remind you that even FBW aircraft are stalled in direct mode for stall characteristics certification which has a very strict set of requirements...regardless of the fact that aircraft will not be there and that there is a stall protection in normal mode...

So question is....can MAX pass basic stall characteristics certification (with pitch up) without MCAS input....I believe answer is obvious. Not to mention the fact that MCAS doesn't have nearly integrity of the FBW system but in essence does same functions in this area.....

I imagine EASA will be flying MCAS-off stall test points to inform their opinion.

I am no expert on aviation fault analysis, but from reading these threads my impression was if expected MCAS failure rate drops below a specified rate then the system can be certified with MCAS on, which is how it was initially certified.

I realize the sanctity of full FBW cannot be challenged, but both EASA and FAA still certify non-FBW aircraft, so standards have been set and the issue is how to meet them.
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:01 pm

par13del wrote:
Not sure why the general point related to MAX versus NSA is being thrown in with the poor design of MCAS, even now, persons are saying that a clean sheet narrow body will not appear until the engine tech gives a larger improvement than what the current NEO engines have provided.

It's also funny how the same people who highlight the poor engineering that MCAS represents turn around and suggest NSA could have been brought to market in a timely way despite it representing a much bigger challenge than MCAS was.

par13del wrote:
On the Airbus and Pratt issue, my bet is that the response will be .....no NEO's have crashed.

At least one almost did, IndiGo has the soiled seat covers to prove it.
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kalvado
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:03 pm

Revelation wrote:

I am no expert on aviation fault analysis, but from reading these threads my impression was if expected MCAS failure rate drops below a specified rate then the system can be certified with MCAS on, which is how it was initially certified.

Probably not. Failure rate of AoA sensors seems to be relatively high - those are fragile parts exposed to airflow and debris-birds, after all. Once that happens, MCAS goes into safety-off, hence failure rate will still be high enough with dual-AoA design/
 
ACATROYAL
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:18 pm

Boy do I ever love reading this conversation... the topics that get mentioned and debated are unbelievable! I popped some more popcorn so keep going ladies and gentlemen..
 
oschkosch
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:20 pm

So there we have it, Boeing CEO now saying RTS "should" be in November... I do wonder when he will say December, then 1st quarter 2020 and so on.

So much for early 4th quarter! And also confirms possible staggered RTS.

https://www.seattletimes.com/business/b ... countries/

Boeing chairman and chief executive Dennis Muilenburg on Wednesday reiterated his projection that, despite concerns publicly expressed by Europe’s air safety regulator, the 737 MAX should begin to return to service around November.

However, he conceded that lack of alignment among international regulatory bodies could mean that the grounded jet may first resume flying in the United States, with other major countries following later.


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ExperimentalFTE
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:21 pm

Revelation wrote:
ExperimentalFTE wrote:
Oh dear, no, not suggesting that nacelle lift is unsolvable...but I am suggesting that philosophy of solving it (as is) is completely unacceptable....

Seems like it is about to be accepted by FAA despite the high visibility created by the bad publicity, which would undermine your statement about complete unacceptability.

ExperimentalFTE wrote:
Let me remind you that even FBW aircraft are stalled in direct mode for stall characteristics certification which has a very strict set of requirements...regardless of the fact that aircraft will not be there and that there is a stall protection in normal mode...

So question is....can MAX pass basic stall characteristics certification (with pitch up) without MCAS input....I believe answer is obvious. Not to mention the fact that MCAS doesn't have nearly integrity of the FBW system but in essence does same functions in this area.....

I imagine EASA will be flying MCAS-off stall test points to inform their opinion.

I am no expert on aviation fault analysis, but from reading these threads my impression was if expected MCAS failure rate drops below a specified rate then the system can be certified with MCAS on, which is how it was initially certified.

I realize the sanctity of full FBW cannot be challenged, but both EASA and FAA still certify non-FBW aircraft, so standards have been set and the issue is how to meet them.


Can't wait to see how it plays out ;)
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:24 pm

jollo wrote:
PixelFlight wrote:
morrisond wrote:
You need to be more precise - in your original post you were implying that there was nothing the crews could do to counteract MCAS. In your own words "Let's not forget that MCAS 1.0 is (or was) an automation system with unlimited authority, vulnerable to single sensor failure, with no input sanitation and no way for human operators to disable it:"

That statement is wrong and implies that whatever the crews did that once MCAS became active they were going to have to ride it to the ground no matter what they did. Casual readers of this thread would easily come to that conclusion based on what you wrote.

I'll stand by my original statement - Hitting the Trim cutoff switches (just like Boeing told Airlines to do after Lionair) or dropping the flaps would have disabled it. Technically you have a point on the trim Cut-off switches as MCAS would still be trying to affect the plane - however with no result - but you keep avoiding the drop the flaps work around.

I was objecting to the Criminal Negligence comment more from a Hyperbole standpoint. I will be amazed if anyone from Boeing or the FAA sees the inside of a Jail cell or faces actual criminal charges.

The disagreement is probably because there is two aspects of the problem in case of a erratic high AoA:

1) From the MCAS point of view: it can be disabled by an action on the trim switches, setting flaps not up, or by the cutoff switches. Only the cutoff switch procedure was documented after JT610 in case of erratic high AoA.

2) From the safety point of view: Using the only documented procedure, the cutoff switches, will not only disable the MCAS but also disable the electric trim, so that only the "too hard to use" trim wheels remains. This is just exchanging a critical problem for an other critical problem. Add that the MCAS have already put the stabilizer in a extreme position and you can see why disabling the MCAS that way will not improve safety. The final problem is that no training was done for the pilot to recognize quickly enough a erratic high AoA fault, to use the electric trim to stop and neutralize MCAS before using the cutoff switches, nor to set the flaps not up to selectively disable MCAS.

Commercial flight safety should not look like an escape game where there is little change to success without any error.


My only issue is one of terminology: as already discussed at length in other posts, I disagreee with the notion that MCAS can be easily disabled by pilots. It can be inhibited by dropping flaps, or its actuator - the electric trim motor - can be cut out (therefore making MCAS control inputs go “unheeded”), but neither action disables the MCAS controller - it’s always on. Mind you, both actions can be effective workarounds to deal with a runaway MCAS: they just don’t disable it.

Otherwise, agree 100% with your post.

I was not my intention to pretend that "MCAS can be easily disabled by pilots", sorry if my post suggest this. I tried to show the difference between a technical aspect (without taken in account the pilot or safety) and a safety aspect of disabling the MCAS.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 7:47 pm

oschkosch wrote:
However, he conceded that lack of alignment among international regulatory bodies could mean that the grounded jet may first resume flying in the United States, with other major countries following later.


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Did anyone really expect any different?
Boeing and the FAA has to be seen to be paying a hefty price, other nations ungrounding the a/c at the same time may be seen as giving tacit approval to the FAA as being competent at their job.
 
MSPNWA
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 8:08 pm

oschkosch wrote:
So there we have it, Boeing CEO now saying RTS "should" be in November... I do wonder when he will say December, then 1st quarter 2020 and so on.

Depends on who is reporting. CNBC is reporting that the CEO again stated an early 4th quarter estimate. Either way it's essentially the same timeline. I wouldn't hold your breath.

https://www.cnbc.com/2019/09/11/boeing- ... -once.html

As we go along, the lack of slippage is a good sign that the estimate will hold. It's firming up day by day. Sounds like the EASA's hand will be called.
 
m66
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 8:34 pm

MSPNWA wrote:
oschkosch wrote:
So there we have it, Boeing CEO now saying RTS "should" be in November... I do wonder when he will say December, then 1st quarter 2020 and so on.

As we go along, the lack of slippage is a good sign that the estimate will hold. It's firming up day by day. Sounds like the EASA's hand will be called.


Oh well, when the 787 was rolled out on July 8, 2007 it was supposed to fly late August (2007) at latest. First flight then was December 2009 if I remember it correctly.
 
Sooner787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 10:05 pm

ExperimentalFTE wrote:
Revelation wrote:
ExperimentalFTE wrote:
Oh dear, no, not suggesting that nacelle lift is unsolvable...but I am suggesting that philosophy of solving it (as is) is completely unacceptable....

Seems like it is about to be accepted by FAA despite the high visibility created by the bad publicity, which would undermine your statement about complete unacceptability.

ExperimentalFTE wrote:
Let me remind you that even FBW aircraft are stalled in direct mode for stall characteristics certification which has a very strict set of requirements...regardless of the fact that aircraft will not be there and that there is a stall protection in normal mode...

So question is....can MAX pass basic stall characteristics certification (with pitch up) without MCAS input....I believe answer is obvious. Not to mention the fact that MCAS doesn't have nearly integrity of the FBW system but in essence does same functions in this area.....

I imagine EASA will be flying MCAS-off stall test points to inform their opinion.

I am no expert on aviation fault analysis, but from reading these threads my impression was if expected MCAS failure rate drops below a specified rate then the system can be certified with MCAS on, which is how it was initially certified.

I realize the sanctity of full FBW cannot be challenged, but both EASA and FAA still certify non-FBW aircraft, so standards have been set and the issue is how to meet them.


Can't wait to see how it plays out ;)


Load up the Euros in a Max, do a few Tex Johnson barrel rolls with the electronics on then off.

If the plane doesn't fall out of the sky, they should be good to go :)
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 10:31 pm

Revelation wrote:
I imagine EASA will be flying MCAS-off stall test points to inform their opinion.


Why would they do this? The aerodynamic stall characteristics of the MAX were determined during the original flight test campaign. MCAS would not have had any effect on that. Or, if MCAS (1.0 or 2.0) does somehow alter the stall characteristics of the airplane then the original certification is no longer valid.
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RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 10:38 pm

Revelation wrote:
oschkosch wrote:
Revelation wrote:

The fact that the MCAS design was totally botched does not undo the market verdict that the MAX was the preferred product.


I normally enjoy your posts, but that just sounds like a bad excuse.

The reality was that the customers were not willing to wait the amount of time it was going to take to do a NSA nor were they willing to pay what it would cost to produce it, nor sacrifice compatibility with all the 737 training and spares they had already purchased for what was probably not a significant gain in fuel burn relative to the competitor.

The reality was that Boeing did not understand how to build CFRP narrow bodies at the rate and cost needed to satisfy the market back in 2011.

The reality is that Boeing needs an effort similar to NMA to prove out the techniques needed for building CRFP airplanes at the required rate and cost needed to satisfy the NSA market, and even that is taking till 2025 or so to achieve.

The reality is the CFRP narrow body is not going to provide much performance gain over the MAX, and in some missions may actually be less efficient, depending on what missions they target the NSA for.

The reality is that NSA was not a viable product back when they made the MAX launch decision in 2011.
The problem was that Boeing was not investing in the NSA when it should have been. A company like Boeing had to plan at least a decade ahead. The fact that there was not an NSA ready to go was on Boeing senior management. Like pretty well everything that has gone wrong at Boeing for the last two decades.

The NSA may not have had a huge advantage over the 737 in terms of economy but the old technology that was in 737 was past it's use by date. Profits would have taken a do but the long term pay of would have been worth it. If your company can plan for long term.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 11, 2019 11:52 pm

RickNRoll wrote:
The problem was that Boeing was not investing in the NSA when it should have been. A company like Boeing had to plan at least a decade ahead. The fact that there was not an NSA ready to go was on Boeing senior management. Like pretty well everything that has gone wrong at Boeing for the last two decades.

The NSA may not have had a huge advantage over the 737 in terms of economy but the old technology that was in 737 was past it's use by date. Profits would have taken a do but the long term pay of would have been worth it. If your company can plan for long term.

My understanding is that Boeing was investing in advance, but still didn't have confidence they could build CFRP narrow bodies at the rate and at the cost of 737/A320 back in 2011, and probably still don't, given that NMA is a much less ambitious target in terms of production volume and cost.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
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RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 12:26 am

Did it have to be CFRP? Wing maybe. The A320 is not CFRP so the competition did not require CFRP had to be used. Like I say. The long term strategic game plan has to be just as important as the short term tactical plan. An all modern technology product line would have generated it's own efficiencies.

The NSA could have had
* adequate ground clearance for next generation engines.
* container capability
* better ground handling
* safer over wing exits
* consistent cockpits over three aircraft types
* inherently safer
* ditch all the accumulated baggage from the 50's
* modern maintenance and debugging systems
 
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BaconButty
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 12:46 am

MSPNWA wrote:
Sounds like the EASA's hand will be called.


It seems that we've moved on from the "foreign" pilots to the EASA in the blame game. It's deeply misguided. Western aviation authorities hegemony in certification is a massive barrier to entry for other nations, as can be seen in China's travails bringing airliners to market. This is based on that regime continuing to deliver impressive results in terms of safety. And the under resourcing of the FAA is putting that advantage in jeopardy. This isn't the FAA vs EASA - this is about resisting the pressures of short termism. I hate to quote myself but I said this three months ago:

I think we'll see a lot of choreographing with the return to service. The likes of EASA will be seen to be tough - in public at least. The FAA will be seen to do penance - and be seemingly subject to a good deal of scrutiny. Boeing may have to suffer longer than strictly necessary, but that might be a price they have to pay. Because certification spinning out of Western hands might be worse for them. China's soft power is something to see these days - I was in Kenya recently, and the place is swarming with their road and rail construction projects. If we see these unaligned nations deferring to Chinese approval via working agreements it will make life more difficult in the long term for Airbus, Boeing et al.


I wonder if we're seeing the results of the choreography now? Or are the FAA, under political and commercial pressure, providing genuine resistance to outside scrutiny? Are Boeing being genuinely uncooperative with EASA? Is their thinking long term or stock price?
Down with that sort of thing!
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 12:51 am

RickNRoll wrote:
Did it have to be CFRP? Wing maybe. The A320 is not CFRP so the competition did not require CFRP had to be used. Like I say. The long term strategic game plan has to be just as important as the short term tactical plan. An all modern technology product line would have generated it's own efficiencies.

The NSA could have had
* adequate ground clearance for next generation engines.
* container capability
* better ground handling
* safer over wing exits
* consistent cockpits over three aircraft types
* inherently safer
* ditch all the accumulated baggage from the 50's
* modern maintenance and debugging systems

I guess we'll never know.

My guess is such a plane would be so more expensive than the competition and so late that it would have no market.

The market doesn't pay for technology for technology's sake.

If it did, 737NG would never have been a success, A320 would have killed it decades ago.

The right decision was to do the MAX, then use NMA to prove out the technology for NSA.

Of course, botching MCAS was not part of the plan, but that's were we find ourselves right now.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 1:00 am

MSPNWA wrote:
oschkosch wrote:
So there we have it, Boeing CEO now saying RTS "should" be in November... I do wonder when he will say December, then 1st quarter 2020 and so on.

Depends on who is reporting. CNBC is reporting that the CEO again stated an early 4th quarter estimate. Either way it's essentially the same timeline. I wouldn't hold your breath.

https://www.cnbc.com/2019/09/11/boeing- ... -once.html

As we go along, the lack of slippage is a good sign that the estimate will hold. It's firming up day by day. Sounds like the EASA's hand will be called.

I listened to live webcast, and he definitely said early Q4. In fact I don't remember Nov being mentioned at all. ok, it was not, here is the transcript.
https://investors.boeing.com/investors/ ... vents=PAST

I'm thoroughly perplexed that no media outlet is triggered by this passage:

Dennis A. Muilenburg wrote:
Yeah. We've really gone through, I'll say, two phases of evaluation, so the original work earlier this year and through mid-year, we focus on MCAS and the improvements to that system, and that was software that we wrapped up in the middle of the year that's been demonstrated and tested. We've had more than 600 flights now with that updated MCAS software. So we feel very confident in that solution and the redundancies that have been built. But since mid-year, we've done a second wave of evaluation where with the FAA and the regulators, we looked more broadly at the entire MAX software system, flight control system as you referred to. And as part of that broader evaluation, we did find another area as was mentioned around mid-year related to flight control computers, where we're able to simulate certain faults that we've never actually seen in flight, but areas where we said, well, we have the opportunity, let's make an additional software update to improve safety. That's the work that we're wrapping up now. So we've done not only an MCAS update, but a holistic system wide evaluation and update to the MAX. That's the work that we're finishing up now.


I guess people see what they wanna see, but I see that unlike the MCAS thing, which he positively said is done, tested and updated. But with regards to the other problems it is only "progress is being made" and "finishing up" now. WTF? Bottom line it is still not ready, so how can the talk with a straight face about early Q4 RTS?
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 1:03 am

Also, why nobody asked specifics about the second update? Did they vet all the questions?
 
1989worstyear
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 1:10 am

Eyad89 wrote:
DenverTed wrote:
Six months after the grounding and 20 years after the NG has been flying with two AOA sensors, EASA decides they need three? Maybe they can make a case for a slow retrofit, but this does not seem like a legitimate reason to delay the return to service.


You know, industry standards tend to evolve and change through time. And this isn’t just true in the aviation industry. What was a common practice 20 years ago in the industry I work in (oil and gas) could simply be unacceptable in 2019.


Grandfathering has been the norm for single aisle aircraft since the early 2000's unfortunately, and innovation peaked in this segment in 1988 with the A320 EIS.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 2:09 am

planecane wrote:
The backstory is a fact as reported by the wall Street journal in an extensive investigative report. If they knew (as you apparently do) that MCAS would be needed at low speed, why would they include the g force sensor in the design? It is pretty clear that they had unexpected flight test results at low speed and decided that expanding the envelope of MCAS was the solution.

The fact that Boeing had stated multiple times that it activates in rarely entered parts of the flight envelope contradicts your assertion that the most susceptible region is just after flaps retraction. This would be a very frequently entered part of the envelope. Pretty much 100%.


Because Boeing (a) knew the safety level was "hazardous" to begin with, and (b) they couldn't get dual AOA sensor redundancy to work (at least not in time for their's and their customer's deadlines).

Item (a) is supported by:
The G-force sensor is an indirect measurement of pitch up moment when combined with high AOA measurement. Therefore, we can conclude that Boeing had a need for dual-sensor design initially for MCAS, and therefore knew the seriousness of MCAS 0.0 - a system that could push the nose down, that wasn't in the pilot FCOM, that wasn't intended to be defeated - and that they initially categorized (internally, not publicly) that seriousness as "hazardous" or higher.

Item (b) is supported by:
They are now attempting dual AOA sensor redundancy + pilot backstop to meet a higher safety level (it's been reported the FAA has reclassified the safety level as catastrophic). If this is now deemed satisfactory for the high-speed corner, one can only conclude they couldn't get dual AOA sensor redundancy to work in MCAS 0.0. And the big difference between G+AOA and AOA+AOA is onside vs offside data.

It's been reported that Boeing classified the microprocessor issue as a "dataflow" issue. It's not hard to conceive that the cross-channel bus, where offside data is fed to the onside FCC, is the root problem that was grandfathered in by grandfathered hardware, and was the limitation for this new anti-stall system.

Therefore, if all of the above is true, then it means Boeing intentionally reclassified the MCAS system as 'major', so they could get the plane certified and to its customers, while continuing to work on a dual AOA sensor design fix that they hoped to have before any crashes occurred. This isn't mere engineering misjudgement.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 2:32 am

RickNRoll wrote:
Did it have to be CFRP? Wing maybe. The A320 is not CFRP so the competition did not require CFRP had to be used. Like I say. The long term strategic game plan has to be just as important as the short term tactical plan. An all modern technology product line would have generated it's own efficiencies.

The NSA could have had
* adequate ground clearance for next generation engines.
* container capability
* better ground handling
* safer over wing exits
* consistent cockpits over three aircraft types
* inherently safer
* ditch all the accumulated baggage from the 50's
* modern maintenance and debugging systems

So how exactly would all of those new features which would have cost billions allow Boeing to compete with the A32XNEO?
All of that technology exist in the A32XNEO at a fraction of the cost to Airbus since they have long since written off the cost, so who was going to pay a multi-million dollar premium to buy a NSA when you could spend half the price on a A32XNEO which does the exact same thing.
Such would only be viable if Boeing was willing to write off the cost of the a/c against itself versus client sales.
My opinion, so no sources.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 2:35 am

ArgentoSystems wrote:
I guess people see what they wanna see, but I see that unlike the MCAS thing, which he positively said is done, tested and updated. But with regards to the other problems it is only "progress is being made" and "finishing up" now. WTF? Bottom line it is still not ready, so how can the talk with a straight face about early Q4 RTS?

Is it the end of September yet, why do we have a problem waiting until the deadline has arrived to say that they failed?
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 2:41 am

ArgentoSystems wrote:
Also, why nobody asked specifics about the second update? Did they vet all the questions?

According to what is posted, they said they were finishing up, we know these were the new requirements given during the MCAS testing in June which was the bit flip issue, what we don't know is how many of the EASA requirements given in April were involved. New items in June would / should be on the finishing up list.
 
MSPNWA
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 3:02 am

m66 wrote:
Oh well, when the 787 was rolled out on July 8, 2007 it was supposed to fly late August (2007) at latest. First flight then was December 2009 if I remember it correctly.

If we're basing things on events over a decade ago, we shouldn't be considering what the EASA thinks about the MAX.

RickNRoll wrote:
The problem was that Boeing was not investing in the NSA when it should have been. A company like Boeing had to plan at least a decade ahead. The fact that there was not an NSA ready to go was on Boeing senior management. Like pretty well everything that has gone wrong at Boeing for the last two decades.

The NSA may not have had a huge advantage over the 737 in terms of economy but the old technology that was in 737 was past it's use by date. Profits would have taken a do but the long term pay of would have been worth it. If your company can plan for long term.


A great plan to spend billions on the potential of a minimal gain/significant loss, stripping billions away from investment in needed areas. Not a good plan to run a successful company. What the MAX has shown is that there was a lot of meat left on the 737 bone, and the decision to build it was unequivocally the right one. Extrapolating an execution misstep into a poor decision to develop is revisionist history.

ArgentoSystems wrote:
I guess people see what they wanna see, but I see that unlike the MCAS thing, which he positively said is done, tested and updated. But with regards to the other problems it is only "progress is being made" and "finishing up" now. WTF? Bottom line it is still not ready, so how can the talk with a straight face about early Q4 RTS?


Uh, because he says it's being finished now, and the RTS estimate is still a few weeks away? How can anyone with a straight face say it won't be early Q4?
Last edited by MSPNWA on Thu Sep 12, 2019 3:04 am, edited 1 time in total.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 3:04 am

sgrow787 wrote:
planecane wrote:
The backstory is a fact as reported by the wall Street journal in an extensive investigative report. If they knew (as you apparently do) that MCAS would be needed at low speed, why would they include the g force sensor in the design? It is pretty clear that they had unexpected flight test results at low speed and decided that expanding the envelope of MCAS was the solution.

The fact that Boeing had stated multiple times that it activates in rarely entered parts of the flight envelope contradicts your assertion that the most susceptible region is just after flaps retraction. This would be a very frequently entered part of the envelope. Pretty much 100%.


Because Boeing (a) knew the safety level was "hazardous" to begin with, and (b) they couldn't get dual AOA sensor redundancy to work (at least not in time for their's and their customer's deadlines).

Item (a) is supported by:
The G-force sensor is an indirect measurement of pitch up moment when combined with high AOA measurement. Therefore, we can conclude that Boeing had a need for dual-sensor design initially for MCAS, and therefore knew the seriousness of MCAS 0.0 - a system that could push the nose down, that wasn't in the pilot FCOM, that wasn't intended to be defeated - and that they initially categorized (internally, not publicly) that seriousness as "hazardous" or higher.

Item (b) is supported by:
They are now attempting dual AOA sensor redundancy + pilot backstop to meet a higher safety level (it's been reported the FAA has reclassified the safety level as catastrophic). If this is now deemed satisfactory for the high-speed corner, one can only conclude they couldn't get dual AOA sensor redundancy to work in MCAS 0.0. And the big difference between G+AOA and AOA+AOA is onside vs offside data.

It's been reported that Boeing classified the microprocessor issue as a "dataflow" issue. It's not hard to conceive that the cross-channel bus, where offside data is fed to the onside FCC, is the root problem that was grandfathered in by grandfathered hardware, and was the limitation for this new anti-stall system.

Therefore, if all of the above is true, then it means Boeing intentionally reclassified the MCAS system as 'major', so they could get the plane certified and to its customers, while continuing to work on a dual AOA sensor design fix that they hoped to have before any crashes occurred. This isn't mere engineering misjudgement.

What does any of this have to do with what I was responding to? The post I responded to was saying that MCAS wasn't originally intended to only operates at high speed and that the problem that MCAS set out to solve is just after flaps retraction.

The MCAS 0.0 use of the g force sensor seems to have only been included as part of an "and" logic statement for the trigger conditions. I don't think it was an attempt at redundancy.
 
2175301
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 3:23 am

sgrow787 wrote:
2175301 wrote:
The FAA did not catch the error in the FMEA Document.


A Seattle Times story cited a Boeing engineer who stated that the FAA did not require the details of the FMEA, only the summary results.

"You turn in your answer," he said. "You don't have to document all your work."


https://www.seattletimes.com/seattle-ne ... afeguards/


Sorry, been too busy to follow this thread:

You are correct; and that is what I would expect. The FAA (and in my industry the NRC) does not see all the work that goes into a FMEA. Just the summary FMEA.

I'm going to describe how FMEAs work where the error almost certainly happened (and likely how). Its been a while since I've described this in this or the crash threads. I think it's very relevant though.

This also relates to the current discussion on potential negligence liability (more on that after I describe FMEAs)

Failure Mode Evaluation & Analysis (although slightly different terminology can be used).

My experience with them is that they are a Form in the 20-30 pages in length that starts off asking for a functional description of the component or system, listing all parts and functions - and any changes from a previous version of the component or system.

The Form you used is based on the component or system (Mechanical components and systems will have a different Form than electronic circuits, from items that have programs in them, etc).

The Form will be broken into into logical sub segments based on what is typical for that kind of component or system.

Each section will then ask a series of questions essentially generated from the previous history of failures from identical or similar components and systems (and the old FMEA Forms of designs 15 years ago that I've reviewed were only about 1/2 as long as the current ones... we keep "finding" new failure modes). Also, probability and significance have changed too (we learn things). Note that FMEAs start with all the accumulated knowledge to date about failure modes, probability of occurrence, and significance (although at times there is room to argue some things a bit one way or another). This is not just asking someone to list what they think can go wrong, its probability, and significance.

I also note that it's been my experience that when a person is first introduced to the forms, they are totally shocked at how many ways (or modes) we already know something can fail.

For each question you have to answer 1st if that is possible or not with the specific component or system. If yes, what is the probability of failure, and the worst case significance when it fails.

I've personally reviewed FMEAs; and at times I've had to ask the preparer for his analysis behind their probability and significance. I have challenged those several times which caused revision to their analysis (and always both My and Their Supervisor and/or Managers thanked me for that, even if the person doing the rework did not - actually only one "author" did not thank me). I once "delayed" final approval of about a half billion dollar project for a month or so on this (a significant Plant Output Up-rate with major equipment changes). That brought a "thank you" from both plant management and out of state corporate leadership (and at least a smile from the regulator's inspector).

But, all that ends up on the form is the result. Not the analysis.

At the end of each sub-section is an open question with a block; generally worded along the line of "Can you conceive of any other potential failure mode in this area not covered above? If so, list them and analyze them."

The person filling this out is fully aware of what the component or system is supposed to do (they will be a key member of the design team); and they are often thinking about how good a job they did. It's very hard for them to see their blind spots or what they missed (that is human nature).

The people reviewing the form will also be fully briefed on the purpose of the design and why things are done the way they are done. They are very susceptible to "Group Think" and may easily miss seeing what was missed (there is a reason those Forms have doubled in length in 15 years in the Nuclear Industry). Actually, for the controls the forms from the suppliers may be the same ones as for aircraft as some of the companies supplying safety critical controls to nuclear plants are supplying safety critical controls to the aviation industry (I have a friend in aviation who is in a position to know - and we talk the same shop when talking about regulations and safety critical requirements, although their are some technical terms that are different. As far as I can tell almost everything regulation and process wise has an exact parallel between nuclear and aviation, except things related to the different end use.

As far as I know, the kind of failure that occurred with the 737max MCAS system has never occurred before. Thus, questions related to it was not on the FMEA Forms for that kind of system (I'm sure they will be in the future).

Now you are asking people to think of things no one has never thought of before or documented a failure like it before; and the form generator is innately blind to what they may have missed, and the others are often highly susceptible to "Group think."

Not easy at all, and only a small % of people have a tendency of routinely thinking outside the box - and just look at how the forms have grown with new failure modes and the changes in probability and significance over the years to see how often things are missed at this stage.

If this kind of failure had been identified at this step in an initial FMEA form; with even an approximately close analysis of significance and probability: I am very sure that the design of the system would have been changed and the kind of MCAS failures that occurred in both events would almost certainly not have (and at least not two failures in about 6 months). Management would not have anything to say - except possibly thanks for finding that. It's not safe. We have to make it safe (or at least arguably so) to meet the probability and severity standards.

I cannot speak about the Aviation Industry; but all of my industry contacts tell me that my personal experiences are not unique; that the Nuclear industry encourages and supports you in finding this kind of stuff - and says "Thank you" when you do.

I have not seen the actual assessment that identified that the failure as at the FMEA stage (there are sources for that). But, I'm pretty sure that its at the "Think of any unasked modes of failure" stage in the process (and that the Forms will grow in length because of it).

Which brings up to the concept of criminal negligence. Intent does not have to be proven. From a practical standpoint the reasonableness of expecting the outcome is considered. A non aviation example (which has played out in the courts in the USA several times in their various cases): If I were to take my hunting rifle out and target shoot in the back yard of my house, and miss whatever I set up as the backstop (or even inadvertently shoot in an unexpected direction) and the bullet penetrated my neighbors house and caused injury of death. I'd almost certainly be held criminally negligent. If I did it with a pellet gun, and unknown to me the neighbor was working on his house and he removed a section of the wall... I would almost certainly not be (no one expects a pellet to have enough energy to cause injury if it gets to my neighbors house).

If I take my hunting riffle out to my brothers place and unknown to us someone happens to be walking in the backwoods half a mile away and I inadvertently injure or kill them. I almost certainly would not be.

If someone has told the police that they intend to kill me (this did actually happen once), and I shoot him while he is breaking into my house (which did not happen- but I thought it was going to one day) - and a bullet goes though a neighbors house wall and caused injury or death. I would almost not have been charged or heald criminally liable.

As it applies to a FMEA: If the error is at the open block question of "Can you think of..." stage. That is, in my opinion, at the point where it is not reasonably foreseeable, and no criminal charges would likely be filed or likely stick in court. Now if they directly missed on a question directly asked... that, in my opinion, would likely be chargeable.

Hope that helps.

Have a great day,

Edited to add: I'm not claiming to be a perfect FMEA reviewer. Others found issues at times where I did not. That is why a team of different people review FMEAs.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 3:37 am

Revelation wrote:
RickNRoll wrote:
The problem was that Boeing was not investing in the NSA when it should have been. A company like Boeing had to plan at least a decade ahead. The fact that there was not an NSA ready to go was on Boeing senior management. Like pretty well everything that has gone wrong at Boeing for the last two decades.

The NSA may not have had a huge advantage over the 737 in terms of economy but the old technology that was in 737 was past it's use by date. Profits would have taken a do but the long term pay of would have been worth it. If your company can plan for long term.

My understanding is that Boeing was investing in advance, but still didn't have confidence they could build CFRP narrow bodies at the rate and at the cost of 737/A320 back in 2011, and probably still don't, given that NMA is a much less ambitious target in terms of production volume and cost.


At the time Boeing said that an NSA didn't make sense unless it could be 15% (I think that was the number) more efficient than the A320NEO and the engines to achieve that would not be available until after 2025. AA wasn't willing to wait and wasn't going to buy NGs when the A320NEO was available so the MAX was born.
 
2175301
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 3:46 am

kalvado wrote:
DenverTed wrote:
Six months after the grounding and 20 years after the NG has been flying with two AOA sensors, EASA decides they need three? Maybe they can make a case for a slow retrofit, but this does not seem like a legitimate reason to delay the return to service.

In case you missed it, two planes crashed because of AoA failures...


I think its more accurate to say that two plane crashes involved MCAS system failures.

We do not know for sure that these were AoA failures (and I personally think that there is evidenced of a possible wiring/connector issue with Lion Air because of the prior days events and I understand that they changed AoA sensor).

We do not actually know that the MCAS failure actually caused the crashes. In the Lion Air case we do know that the Pilot was successfully controlling the aircraft with MCAS failure for a number of minutes, and that the crash only occurred after the controls were turned over to the Co-Pilot. We also know that the day before that the whoever was flying the aircraft did not loose control during MCAS failure and they (with the help of a 3rd pilot) successfully troubleshot and functionally turned off the MCAS system.

We also know that in the Ethiopian Crash that there are at least other factors to consider, such as why was the aircraft above VMO.

The only thing we actually know at this point (as the final reports have not been issued) is that a malfunctioning MCAS system occurred as part of a sequence of events that resulted in two airplanes crashes.

Have a great day,
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 4:53 am

So Boeing is on track, nice.
 
kevin5345179
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 5:57 am

par13del wrote:
ArgentoSystems wrote:
I guess people see what they wanna see, but I see that unlike the MCAS thing, which he positively said is done, tested and updated. But with regards to the other problems it is only "progress is being made" and "finishing up" now. WTF? Bottom line it is still not ready, so how can the talk with a straight face about early Q4 RTS?

Is it the end of September yet, why do we have a problem waiting until the deadline has arrived to say that they failed?


because you need to have test flight with FAA first before submitting final certificate document and it will take ~ 1 month to review IIRC
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 6:47 am

Sooner787 wrote:
Load up the Euros in a Max, do a few Tex Johnson barrel rolls with the electronics on then off.

If the plane doesn't fall out of the sky, they should be good to go :)


Faulty thinking.

Barrel rolls don't expose much in view of problematic flight envelope fringe behavior.
The keyword here is "sufficient test coverage".
The majority of offered and or executed "tests" lack proper coverage and thus
prove nothing. Neither thumbs up nor thumbs down.
Murphy is an optimist
 
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enzo011
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 7:02 am

seahawk wrote:
So Boeing is on track, nice.



And on track means the aircraft has not flown a commercial flight in 6 months and no deliveries in the same time and we still don't know exactly when it will return to service, then yes they are most definitely on track.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 7:13 am

planecane wrote:
Revelation wrote:
RickNRoll wrote:
The problem was that Boeing was not investing in the NSA when it should have been. A company like Boeing had to plan at least a decade ahead. The fact that there was not an NSA ready to go was on Boeing senior management. Like pretty well everything that has gone wrong at Boeing for the last two decades.

The NSA may not have had a huge advantage over the 737 in terms of economy but the old technology that was in 737 was past it's use by date. Profits would have taken a do but the long term pay of would have been worth it. If your company can plan for long term.

My understanding is that Boeing was investing in advance, but still didn't have confidence they could build CFRP narrow bodies at the rate and at the cost of 737/A320 back in 2011, and probably still don't, given that NMA is a much less ambitious target in terms of production volume and cost.


At the time Boeing said that an NSA didn't make sense unless it could be 15% (I think that was the number) more efficient than the A320NEO and the engines to achieve that would not be available until after 2025. AA wasn't willing to wait and wasn't going to buy NGs when the A320NEO was available so the MAX was born.

A short term drop in profits would have been a reasonable price to pay for the NSA. This was at at time when they already knew that the NG had safety risks. The NSA in retrospect would have been a better deal. The were always going to have to make it, all they did was kick the can down the road.
 
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scbriml
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 7:13 am

BaconButty wrote:
It seems that we've moved on from the "foreign" pilots to the EASA in the blame game.


ABB Syndrome is quite contagious apparently.
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jollo
Posts: 381
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 7:33 am

2175301 wrote:
As far as I know, the kind of failure that occurred with the 737max MCAS system has never occurred before. Thus, questions related to it was not on the FMEA Forms for that kind of system (I'm sure they will be in the future).
[...]
As it applies to a FMEA: If the error is at the open block question of "Can you think of..." stage. That is, in my opinion, at the point where it is not reasonably foreseeable, and no criminal charges would likely be filed or likely stick in court. Now if they directly missed on a question directly asked... that, in my opinion, would likely be chargeable.


Thanks 2175301, great post, fascinating insight into the workings of what has to be one of the strictest-regulated industries.

However I do no agree with your opinion of where the error most likely occurred in MCAS 1.0 FMEA: in my opinion, the "catastrophic" classification should have stemmed directly from the "know failure modes" section, not from the "open questions" section in the back.

It's true that the kind of MCAS failures that killed 300+ people never occurred before, but that's only because no such design was ever allowed on an airliner. The nearest comparable system is - AFAIK - the MCAS system on KC-767A flying for the Italian Air Force, but it's wired with dual AOA input channels and input sanitation, i.e. it automatically disables itself on an AOA disagree condition (I have no idea about control authority).

In automation design, a single-input, unlimited authority controller with no input sanitation and no sane manual override option is almost guaranteed to fail catastrophically in a single sensor failure scenario (N.B.: in most automation applications, a "catastrophic" failure often only results in damage to equipment, but it's still the most unwanted outcome of operations). With AOA sensors having a none-too-high MTBF, the frequency calculation was straightforward (and grim reality confirmed it, sadly).

If anything, probably the flaw was difficult to identify because it was so fundamental, and none of the questions in the "known failure modes" section were anything like "is your design vulnerable to single-sensor failures and does the controller have unlimited authority and did you neglect to put in place even rudimentary input sanitation filters and did you change the function of the only cut out switch that could have disabled the controller without disabling the actuator?"

Not because any of the failure modes were unknown, but because no one could imagine that a group of professionals could line up this frankly unthinkable combination of basic design criteria violations in a single piece of equipment.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 12, 2019 7:53 am

Many thanks for your precise explanation of the FMEA :thumbsup:

2175301 wrote:
As far as I know, the kind of failure that occurred with the 737max MCAS system has never occurred before. Thus, questions related to it was not on the FMEA Forms for that kind of system (I'm sure they will be in the future).

Now you are asking people to think of things no one has never thought of before or documented a failure like it before; and the form generator is innately blind to what they may have missed, and the others are often highly susceptible to "Group think."

Not easy at all, and only a small % of people have a tendency of routinely thinking outside the box - and just look at how the forms have grown with new failure modes and the changes in probability and significance over the years to see how often things are missed at this stage.

If this kind of failure had been identified at this step in an initial FMEA form; with even an approximately close analysis of significance and probability: I am very sure that the design of the system would have been changed and the kind of MCAS failures that occurred in both events would almost certainly not have (and at least not two failures in about 6 months). Management would not have anything to say - except possibly thanks for finding that. It's not safe. We have to make it safe (or at least arguably so) to meet the probability and severity standards.

I cannot speak about the Aviation Industry; but all of my industry contacts tell me that my personal experiences are not unique; that the Nuclear industry encourages and supports you in finding this kind of stuff - and says "Thank you" when you do.

I have not seen the actual assessment that identified that the failure as at the FMEA stage (there are sources for that). But, I'm pretty sure that its at the "Think of any unasked modes of failure" stage in the process (and that the Forms will grow in length because of it).


The problem is that "the kind of failure that occurred with the 737max MCAS system has never occurred before" only because the MCAS (as in the 737-8/9 MAX) didn't exit before. I agree that the MCAS do make action on a safety critical control surface so must be classified as safety critical, triggering a FMEA. But I disagree that the FMEA of the MCAS is too complex to have missed the single erratic AoA failure mode at the input of MCAS. The single AoA input cam from the very top level of the MCAS blocs schematic analysis. And single erratic AoA failure is know to have a probability incompatible with the safety critical level without proper mitigation.

Until we have more information about the MCAS FMEA, all scenarios are speculatively possible, but the "Think of any unasked modes of failure" stage in the process is the less probable to me, or done by someone that didn't know that MCAS can operate from a single sensor at low speed (a communication quality problem). Either the FMEA MCAS was not done in the rush of the last minute change of the MCAS to include the "low speed pitch down function", or the FMEA did abuse of the pilot existing procedure to mitigate the single erratic AoA input probability of failure mode.

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