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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 8:04 am
by sgrow787
2175301 wrote:
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.


At this point I would wager that no one actually cares - besides Boeing and the FAA - what the crash reports eventually say. It's what we know now about the certification, the grounding, and the re-certification that really matters. In fact I would trade you the crashes for full description of MCAS in the FCOM, since there would still be a grounding when pilots started asking where the AOA disagree light was, and why don't they get simulator time for this weird thing that cycles on for 10 sec and off for 5, and "wait, you mean to tell me the authority is 2.5 deg/cyc".

As for "malfunctioning MCAS system", let's call it what it is - a malfunctioning flight control system due to a mis-certified subsystem that incorrectly reads AOA data (it's supposed to look at both AOA sensors, but only looked at one). Hence the solution Boeing is preparing is a system re-design, and not a software fix or update.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 8:11 am
by Noshow
MCAS did was it was supposed to do. However it was triggered when not needed. Over and over again.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 9:58 am
by planecane
RickNRoll wrote:
planecane wrote:
Revelation wrote:
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.


What safety risks did they know the NG had after 14 years and a few thousand frames in service with no design related hull losses? The rudder actuators had been taken care of by then.

They would have had to slash the price of the NG significantly, possibly to the point of no profit in order to sell any against the A320NEO. If they would have tried to keep selling the NG against the NEO, it is possible that Bombardier would still own the c-series because that would have opened a huge door to them as well.

If they had made an NSA with A320NEO engines they would have accomplished spending 5-10x what Airbus spent on development for an aircraft that might be 2 or 3 percent more efficient. Then, it would have made absolutely no financial sense to consider a new NSA just 5 or 6 years into the service of that hypothetical NSA when the engine technology advanced. It might not be a case of just needing to re-engine. If open rotor or some other technology becomes viable in the middle of the next decade, it may have required relocating the engines. There was no way to predict that in 2010/2011.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 10:41 am
by seb76
seahawk wrote:
So Boeing is on track, nice.

A broken clock still displays the correct time twice a day...

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 10:43 am
by asdf
kevin5345179 wrote:
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


rubberstamping needs just a few hours ...

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 10:47 am
by par13del
kevin5345179 wrote:
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

Well my understanding is different from yours, my expectations is that:
1. Boeing submits their fixes to the FAA via documentation.
2. FAA reviews the documentation and either accepts or rejects.
3. If rejected the cause is provided and discussions commence on rectification
4. If accepted, test flights are scheduled to be conducted by FAA test pilots to validate what Boeing has submitted.

Yes Boeing is conducting test flights, but just as in June, when the fixes were submitted, the FAA then requested their own test flights conducted under their own supervision and direction.

I expect the same to take place now, if I am wrong then fine,

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 10:53 am
by ExperimentalFTE
Global regulatory scrutiny threatens Boeing's Max timeline: CEO

https://www.flightglobal.com/news/artic ... ti-460806/

Well how nicely said (sarcasm).....Dennis, Dennis.....I wouldn't do that if I was you...

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 10:59 am
by Polot
ExperimentalFTE wrote:
Global regulatory scrutiny threatens Boeing's Max timeline: CEO

https://www.flightglobal.com/news/artic ... ti-460806/

Well how nicely said (sarcasm).....Dennis, Dennis.....I wouldn't do that if I was you...

I don’t really think anything Dennis said was controversial in that article. He said they are targeting 4th quarter return to service but conceded that global regulatory agencies can throw that timeline off but Boeing are in continuing discussions with EASA and others to address all their concerns.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:11 am
by Noshow
Better don't blame certification authorities now when you need them most.
(After having blamed customer pilots when you needed them most.)

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:13 am
by ExperimentalFTE
Polot wrote:
ExperimentalFTE wrote:
Global regulatory scrutiny threatens Boeing's Max timeline: CEO

https://www.flightglobal.com/news/artic ... ti-460806/

Well how nicely said (sarcasm).....Dennis, Dennis.....I wouldn't do that if I was you...

I don’t really think anything Dennis said was controversial in that article. He said they are targeting 4th quarter return to service but conceded that global regulatory agencies can throw that timeline off but Boeing are in continuing discussions with EASA and others to address all their concerns.


I kind of read it differently and my takeaway is somewhat down the line of "hey we would put it back in service but regulators are holding us up" and in my experience it is never good to criticize regulators....

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:17 am
by Polot
ExperimentalFTE wrote:
Polot wrote:
ExperimentalFTE wrote:
Global regulatory scrutiny threatens Boeing's Max timeline: CEO

https://www.flightglobal.com/news/artic ... ti-460806/

Well how nicely said (sarcasm).....Dennis, Dennis.....I wouldn't do that if I was you...

I don’t really think anything Dennis said was controversial in that article. He said they are targeting 4th quarter return to service but conceded that global regulatory agencies can throw that timeline off but Boeing are in continuing discussions with EASA and others to address all their concerns.


I kind of read it differently and my takeaway is somewhat down the line of "hey we would put it back in service but regulators are holding us up" and in my experience it is never good to criticize regulators....

We are reading words off a screen (so no idea of tone), and not even the full speech (or answer, as this was likely in response to investors), only snippets that FG copied. “Takeaways” are entirely based on preexisting opinions of Dennis/Boeing/etc.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:18 am
by seahawk
That is not a problem, however saying that EASA has questions that Boeing are working their way through and then claiming that only the timeline of EASA to lift the grounding is the limiting factor for the timeline, could raise some eyebrows.
Because that means, that the questions are either stupid or pointless, as he rules out that the answers to those question might lead to additional work for Boeing, which would also change the timeline.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:27 am
by Polot
seahawk wrote:
That is not a problem, however saying that EASA has questions that Boeing are working their way through and then claiming that only the timeline of EASA to lift the grounding is the limiting factor for the timeline, could raise some eyebrows.
Because that means, that the questions are either stupid or pointless, as he rules out that the answers to those question might lead to additional work for Boeing, which would also change the timeline.

He doesn’t fully rule that there may be additional work, just claims that he feels that he can satisfy EASA without hardware changes. I’m not sure how answering a question without needing additional work (theoretically, because who knows how things will shake out) automatically means the questions are stupid or pointless, that is too much of a logic leap for me.

Granted EASA probably is the biggest limiting factor, I suspect most agencies other than China and maybe a few others to rubberstamp EASA’s approval.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:38 am
by kayik
Where did he say those? At an investors conference. They are just giving positive messages to keep the share price level. Nothing serious. On the other hand,EASA repeated their 4 points after 6 months. Any progress there?

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 12:05 pm
by bob75013
kayik wrote:
Where did he say those? At an investors conference. They are just giving positive messages to keep the share price level. Nothing serious. On the other hand,EASA repeated their 4 points after 6 months. Any progress there?



Ah, so you think the CEO lied to investors in hopes the lie would not be discovered?

Gotcha...

The stock is up something like $53/share in two weeks,. Institutions own the vast majority of the company, and I submit that those institutions (that own tens of billions of $ of stock each) know a lot more about the MAX situation than 99+% of a-net viewers.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 12:29 pm
by WIederling
bob75013 wrote:
kayik wrote:
Where did he say those? At an investors conference. They are just giving positive messages to keep the share price level. Nothing serious. On the other hand,EASA repeated their 4 points after 6 months. Any progress there?



Ah, so you think the CEO lied to investors in hopes the lie would not be discovered?

Gotcha...


The stock is up something like $53/share in two weeks,. Institutions own the vast majority of the company, and I submit that those institutions (that own tens of billions of $ of stock each) know a lot more about the MAX situation than 99+% of a-net viewers.


Yawn.
you are munging "moral" <> "legal" lie. Lots of misdirection placed via "we did not know any better at the time"
dog ate my homework kind of squiggling out in the corporate domain.

And i don't think that stockholders ( especially the corporate ones ) are real world savy.
Stock markets are mostly unlinked to reality. performance of Boeing stock is an up front example.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 12:29 pm
by Revelation
planecane wrote:
If they had made an NSA with A320NEO engines they would have accomplished spending 5-10x what Airbus spent on development for an aircraft that might be 2 or 3 percent more efficient. Then, it would have made absolutely no financial sense to consider a new NSA just 5 or 6 years into the service of that hypothetical NSA when the engine technology advanced. It might not be a case of just needing to re-engine. If open rotor or some other technology becomes viable in the middle of the next decade, it may have required relocating the engines. There was no way to predict that in 2010/2011.

This jives with what I wrote, in that airlines don't pay for technology just for technology's sake.

If they did, the NG would not have been successful against the A320.

The real issue isn't that the MAX was a bad decision, the real issue is that the MCAS implementation was FUBAR'd.

Polot wrote:
He doesn’t fully rule that there may be additional work, just claims that he feels that he can satisfy EASA without hardware changes.

To me, the most interesting quote was, "A phased ungrounding of the airplane among regulators around the world is a possibility.".

Yet another indication that the US is willing to go first on its own and wait for others to catch up.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 12:46 pm
by bob75013
WIederling wrote:
bob75013 wrote:
kayik wrote:
Where did he say those? At an investors conference. They are just giving positive messages to keep the share price level. Nothing serious. On the other hand,EASA repeated their 4 points after 6 months. Any progress there?



Ah, so you think the CEO lied to investors in hopes the lie would not be discovered?

Gotcha...


The stock is up something like $53/share in two weeks,. Institutions own the vast majority of the company, and I submit that those institutions (that own tens of billions of $ of stock each) know a lot more about the MAX situation than 99+% of a-net viewers.


Yawn.
you are munging "moral" <> "legal" lie. Lots of misdirection placed via "we did not know any better at the time"
dog ate my homework kind of squiggling out in the corporate domain.

And i don't think that stockholders ( especially the corporate ones ) are real world savy.
Stock markets are mostly unlinked to reality. performance of Boeing stock is an up front example.


Institutional "stockholders" jobs depend on producing results.If they don't they get canned. They re far more real world savvy than you. CEOs don't lie to institutions. They lose their jobs when they do.

Let's talk about Boeing's stock price being unlinked to reality about November 1 - when it is about $420 and MAXs are flying.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 1:12 pm
by Revelation
bob75013 wrote:
WIederling wrote:
Yawn.
you are munging "moral" <> "legal" lie. Lots of misdirection placed via "we did not know any better at the time"
dog ate my homework kind of squiggling out in the corporate domain.

And i don't think that stockholders ( especially the corporate ones ) are real world savy.
Stock markets are mostly unlinked to reality. performance of Boeing stock is an up front example.


Institutional "stockholders" jobs depend on producing results.If they don't they get canned. They re far more real world savvy than you. CEOs don't lie to institutions. They lose their jobs when they do.

Let's talk about Boeing's stock price being unlinked to reality about November 1 - when it is about $420 and MAXs are flying.

We did read about heads rolling within the 737 team in an article posted to this thread that was quickly withdrawn.

It'll be interesting to see if DM keeps his head or not.

My vote would be that he's gone one or two quarters after world wide ungrounding.

Fairly or unfairly, his name and face are now directly linked to the MCAS debacle.

Corporations often draw a line under bad times by putting a new face into the CEO chair.

Institutional investors will be key as to whether or not he stays or goes.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 1:52 pm
by JetBuddy
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.


However, there was a middle way here.

And that is something we've discussed in these forums for years. Updating the main landing gear and wing box to lift the fuselage up from the ground sufficiently so that mounting the new engines forward and up was not necessary. I believe this is something that could be done without jeopardizing the grandfathering certification rights - as there are many examples of planes flying on the same certification with very different MLG arrangements. Maybe this would have delayed the introduction of the MAX by 6-12 months.

Instead they made the grave mistake of taking shortcuts and mounting the large engines they way they did.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 1:55 pm
by Scotron12
To be fair to.Muilenburg...he is an engineer. I wonder deep inside how he really feels on the MAX issue. You certainly never see it.

Seems to soundbite the corporate line...I guess he must do.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 2:02 pm
by par13del
Well based on all the digging going on I would think that someone will find something which shows why they chose not to adjust wing box and landing gear to accommodate the larger engines while preserving grandfathering. Even that cost if allowed would be less than a new build, my opinion is it would not have been allowed, too many changes to a non FBW a/c in a FBW environment.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 2:11 pm
by Revelation
JetBuddy wrote:
Instead they made the grave mistake of taking shortcuts and mounting the large engines they way they did.

IMO the grave mistakes were in the MCAS design and implementation, and not in the way the engines were mounted.

There's a lot of unappealing things about a bigger and heavier wingbox and gear arrangement beyond the cost and time to develope it.

There are all kinds of un-asthetic mechanisms on non-FBW airplanes to augment stability, going back to the yaw damper fitted on 707 after "dutch roll" was discovered.

IMO the main issue here is that MCAS was FUBAR'd.

And since slagging Boeing is a theme, how can we be sure that an all-new gearbox and landing gear would not end up having some pretty problematic short comings?

Boeing should be able to pull that off, but that's what we would say about MCAS, and about GE and RR's ability to provide durable blade coatings, and PW's ability to produce reliable bearings, etc.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 2:57 pm
by flipdewaf
JetBuddy wrote:
However, there was a middle way here.

And that is something we've discussed in these forums for years. Updating the main landing gear and wing box to lift the fuselage up from the ground sufficiently so that mounting the new engines forward and up was not necessary. I believe this is something that could be done without jeopardizing the grandfathering certification rights - as there are many examples of planes flying on the same certification with very different MLG arrangements. Maybe this would have delayed the introduction of the MAX by 6-12 months.
The 737 certification is around the egress of the passengers in the even of an emergency and the height of the trailing edge of the wing which is used in emergency evacuations means that the aircraft does not need exit slides. The 737 wing is on the limit of this height (likely not a coincidence). If the height of the trailing edge of the wing is increased then slides are required and then the aircraft requires re-certification because of the the new egress requirements and effectively becomes a new type. The rules as they stand do not allow you to carry grandfathering from one type to another and as such the whole 737 would need certifying to the current standards at which point you may as well design a new jet. Boeing haven't been trying to be creative with engine packaging and placement on the 737 since 1981 because they didn't want to put longer gear on it, they wanted to put longer gear on but NASAT gets in the way.

Fred

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 5:49 pm
by airnorth
More AC MAX flights I see that C-FTJV is zipping around Quebec and Ontario again today doing some kind of test flights? Anyone have insight on what these flights are for?

https://www.flightradar24.com/ACA2353/221308c2

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 5:51 pm
by oschkosch
I believe Boeing would be better off not betting on a staggered RTS but in waiting for full global RTS and approval by not just the FAA but also EASA, CAAC and others for the max. That would show the world that safety comes before profit and that they've learnt from this horrible mistake.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 6:42 pm
by hivue
oschkosch wrote:
I believe Boeing would be better off not betting on a staggered RTS but in waiting for full global RTS and approval by not just the FAA but also EASA, CAAC and others for the max. That would show the world that safety comes before profit and that they've learnt from this horrible mistake.


Reality likely will rule here. Waiting out the very last sovereign aviation authority giving the thumbs up to the MAX could put RTS another year away, requiring Boeing to shut down the assembly line at some point. That ain't going to happen unless the FAA delays its OK into 2020.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 6:43 pm
by par13del
oschkosch wrote:
I believe Boeing would be better off not betting on a staggered RTS but in waiting for full global RTS and approval by not just the FAA but also EASA, CAAC and others for the max. That would show the world that safety comes before profit and that they've learnt from this horrible mistake.

That's for Boeing, however, since the FAA has been playing middle man and it is their responsibility to clear the a/c to fly in the USA, let's see the FAA give clearance to show the world that they are responsible and competent in doing their job. Then, let's see Boeing fall on their sword and tell the USA domestic airlines and the world over that they will not deploy the fix to the grounded a/c until EASA and other regulators around the world are satisfied.
How's that for an option, the FAA does its job and Boeing continues to take a hit to show the world that they are sorry and now sensitive to their needs and demands?

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 7:20 pm
by SEU
Noshow wrote:
MCAS did was it was supposed to do. However it was triggered when not needed. Over and over again.


So it didnt do what it was meant to...

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 8:12 pm
by sgrow787
SEU wrote:
Noshow wrote:
MCAS did was it was supposed to do. However it was triggered when not needed. Over and over again.


So it didnt do what it was meant to...


It didnt do what a safe design and properly certified system is supposed to do.

But it did exactly what it was meant to do when designed by a company that manufactures their own failure mode analysis, their own safety classification, concealing information from pilots and regulators, and essentially not putting safety first.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Thu Sep 12, 2019 11:55 pm
by 2175301
jollo wrote:
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.


We may disagree; but, my experience is that unless questions are rather direct in the list of questions section (and they often are written several different ways to get you to think of a failure mode) that most people will not see them. If the key type of questions were there I have a high confidence that the failure that occurred from a continuous false reading (be it from a sensor, wiring fault. etc.) would have been identified and classified appropriately; forcing a revision to the design (and again to the FMEA) in order to progress. Overall preventing the events.

As far as whys such seemingly obvious errors occur. When I graduated from College with my Engineering Degree I could not believe all the mistakes that people were making. Decades later, and my own series of mistakes... (which I often exclaimed to at least myself how could I have missed that - perhaps not in so kind of words) and experience with high level Human Performance (I was a founding member of our Plant's Human Performance Committee and have years of training in it - some provided by the same company that trains Aerospace and Medical on Human Performance - and dealing with it); and dealing with FMEAs.... (where sometimes we catch things, and sometimes we don't: Where I may see a miss, and others see other misses that I missed)... I no longer try to explain other than to say that we are human and humans make mistakes. Most everything is obvious after the fact (as is this case). But, in the case of FMEAs a team of people looked at them and thought they were correct (or as correct as they could make them). Unfortunately, misses occur - and sometimes significant misses occur.

I have never seen a significant miss if the base questions that identified the failure mode was on the FMEA. Thus, I suspect that the questions were not their that would lead people to foresee this failure. They classified the system as acceptable based on the questions that were there, and did not think enough outside of their structured box to add the issue to the "Can you think of... box." The nature of the FEMA forms constantly add the events that occur so that they should be caught before hand in the future. But, those forms did not exist long ago. I think the formal FEMA process is about 25 years old.

As far as fundamental engineering principals... It's amazing how often engineers don't apply those. I've seen it too many times to count; and with some of the most basic things. Example: How could a historic well known small turbine manufacture design a Safety Related emergency service steam turbine based pump to supply water to cool the reactor- that has to start from cold with 500 F steam and be up to full load in a minute.. and run for hours.... forget to design it for thermal expansion... (I was the lead investigator on the root cause for why that turbine had problems - 3-4 months out of my life). But, I believe experiencing and seeing all of this has made me a better engineer.

Have a great day,

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 3:34 am
by RickNRoll
Revelation wrote:
planecane wrote:
If they had made an NSA with A320NEO engines they would have accomplished spending 5-10x what Airbus spent on development for an aircraft that might be 2 or 3 percent more efficient. Then, it would have made absolutely no financial sense to consider a new NSA just 5 or 6 years into the service of that hypothetical NSA when the engine technology advanced. It might not be a case of just needing to re-engine. If open rotor or some other technology becomes viable in the middle of the next decade, it may have required relocating the engines. There was no way to predict that in 2010/2011.

This jives with what I wrote, in that airlines don't pay for technology just for technology's sake.

If they did, the NG would not have been successful against the A320.

The real issue isn't that the MAX was a bad decision, the real issue is that the MCAS implementation was FUBAR'd.

Polot wrote:
He doesn’t fully rule that there may be additional work, just claims that he feels that he can satisfy EASA without hardware changes.

To me, the most interesting quote was, "A phased ungrounding of the airplane among regulators around the world is a possibility.".

Yet another indication that the US is willing to go first on its own and wait for others to catch up.


Yet in hindsight we know that Boeing made the wrong decision. They did not assess the risks adequately. If the 737 had been a comparable plane to the A320 in technology, that would have been a reasonable conclusion to come to. The 737 wasn't comparable. Employee feedback would have already been telling them that the risks were increasing, quite loudly.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 5:03 am
by sgrow787
2175301 wrote:
As far as I know, the kind of failure that occurred with the 737max MCAS system has never occurred before.


Certainly sensors have failed before. And pilots fail too. The problem with this particular failure is that it was a relatively simple system that was being added to an already-tested grandfathered-in flight control system. Two or three inputs, with redundancy, and one output - the horizontal stabilizer trim. Just because the legacy hardware made it all but impossible to implement doesn't change the basic failure modes of such a system.

What are inputs?
What are the outputs?
What are the flight modes?
Which of those modes are considered safety critical for a failed stabilizer? for failed stabilizer up? for down?
What are the possible misfires?
Is there a single point of failure?

It would be inconceivable that anybody believes Boeing didn't understand the failure modes for MCAS. Afterall, is it just coincidence they readjusted test pilot roles at the same time they were changing MCAS to single-sensor (from G+AOA) and higher authority? According to this source, Boeing kept its own test pilots out of the loop when those design changes were made:

https://www.marketwatch.com/story/boein ... 2019-05-03

Is that coincidence? Or did they know the test flights their pilots would have been tempted to do, would have failed their design?

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 6:42 am
by PixelFlight
2175301 wrote:
jollo wrote:
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.


We may disagree; but, my experience is that unless questions are rather direct in the list of questions section (and they often are written several different ways to get you to think of a failure mode) that most people will not see them. If the key type of questions were there I have a high confidence that the failure that occurred from a continuous false reading (be it from a sensor, wiring fault. etc.) would have been identified and classified appropriately; forcing a revision to the design (and again to the FMEA) in order to progress. Overall preventing the events.

As far as whys such seemingly obvious errors occur. When I graduated from College with my Engineering Degree I could not believe all the mistakes that people were making. Decades later, and my own series of mistakes... (which I often exclaimed to at least myself how could I have missed that - perhaps not in so kind of words) and experience with high level Human Performance (I was a founding member of our Plant's Human Performance Committee and have years of training in it - some provided by the same company that trains Aerospace and Medical on Human Performance - and dealing with it); and dealing with FMEAs.... (where sometimes we catch things, and sometimes we don't: Where I may see a miss, and others see other misses that I missed)... I no longer try to explain other than to say that we are human and humans make mistakes. Most everything is obvious after the fact (as is this case). But, in the case of FMEAs a team of people looked at them and thought they were correct (or as correct as they could make them). Unfortunately, misses occur - and sometimes significant misses occur.

I have never seen a significant miss if the base questions that identified the failure mode was on the FMEA. Thus, I suspect that the questions were not their that would lead people to foresee this failure. They classified the system as acceptable based on the questions that were there, and did not think enough outside of their structured box to add the issue to the "Can you think of... box." The nature of the FEMA forms constantly add the events that occur so that they should be caught before hand in the future. But, those forms did not exist long ago. I think the formal FEMA process is about 25 years old.

As far as fundamental engineering principals... It's amazing how often engineers don't apply those. I've seen it too many times to count; and with some of the most basic things. Example: How could a historic well known small turbine manufacture design a Safety Related emergency service steam turbine based pump to supply water to cool the reactor- that has to start from cold with 500 F steam and be up to full load in a minute.. and run for hours.... forget to design it for thermal expansion... (I was the lead investigator on the root cause for why that turbine had problems - 3-4 months out of my life). But, I believe experiencing and seeing all of this has made me a better engineer.

Have a great day,

Of course, from the little we know now, the type of mistake you describes as "the questions were not their that would lead people to foresee this failure" is technically still a possibility. I understand that your experience make this possibility real. But a single sensor activating a safety critical control surface is the kind of mistake so obvious that it could'n have passed the required review. Go back in time when Boeing and FAA issued the EAD where there have to describes the problem and read the reaction back then. The amount of peoples chocked about that single sensor design was colossal, from engineer, from pilots, from anyone with basic interest in safety. Based on that, you have to think about others possibilities to explain the FMEA failure.

The EAD is entirely redacted around the pilot mitigation of the single sensor failure to avoid the risk of erratic activation of a safety critical control surface. There are journalists that have published information about how the MCAS was hidden to the pilots because it was believed to be like others existing systems that can move the horizontal stabilized actuator. Based on this, I found far more possible that the FMEA did correctly identify the risk of an erratic single sensor failure, but that the mitigation of that risk was wrong. Normally most peoples logically wanted to add a redundancy in that case, like on any others modern aircraft, but the obsolete architecture of the 737 was not designed to do that properly without a major redesign (the one that actually Boeing take so many months to do). At some point, the idea of using the pilot to mitigate the MCAS activation of the safety critical control surface was proposed. There is nothing wrong in exploring all ideas, but that idea was not correctly assessed from a safety point of view. I my opinion it was at this stage that most of the Emmental cheese holes aligned:
* Risk of single AoA sensor failure.
* Activation of a safety critical control surface.
* Abuse of the notion of "trim runaway" to mitigate the risk by the pilot.
* "Same type rating" objective inciting to hide the MCAS.
* Consequently, no appropriate documentation for the pilots.
* Consequently, no appropriate training for the pilots.
* Multiple discontinue activation of the MCAS can put the stab in a extreme position.
* Loss of elevator authority on extreme stab trim position.
* Too small trim wheels unusable at high speed.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 7:41 am
by bennett123
Several people have discussed whether the MCAS could have been disabled by the pilots, and what actions would have had this effect/the consequences of taking this action.

What I do not understand, is how any of this is relevant given that the pilots/airlines apparently did not know MCAS existed.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 8:09 am
by WIederling
bennett123 wrote:
Several people have discussed whether the MCAS could have been disabled by the pilots, and what actions would have had this effect/the consequences of taking this action.

What I do not understand, is how any of this is relevant given that the pilots/airlines apparently did not know MCAS existed.


Any super competent pilot ( the majority in the US pilot pool :-) would have instinctively known how to do it.
Just like ducks take to water.

All the side alleys visited in these contrived discussion ( here, media ) shows that
there was utmost care spent from the Boeing side of things
on setting this up as "we are the best and couldn't have known any better"
to explain this FUBARed design transition.

I no longer deem this an unfortunate bad decission but
a carefully crafted dangerous decission to "keep up with the Joneses"
on the cheap.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 8:41 am
by WIederling
https://www.moonofalabama.org/
currently on top of the page
else go to
"September 12, 2019 Boeing Foresees Return Of The 737 MAX In November - But Not Everywhere"

nice collection of media transpiration.
they come to the tentative conclusion that
currently a staged return to service seems to be envisioned for November.
FAA and US first. ...
this may fall on various institutions ( like insurance companies, passengers ) balking.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 9:07 am
by PixelFlight
WIederling wrote:
https://www.moonofalabama.org/
currently on top of the page
else go to
"September 12, 2019 Boeing Foresees Return Of The 737 MAX In November - But Not Everywhere"

nice collection of media transpiration.
they come to the tentative conclusion that
currently a staged return to service seems to be envisioned for November.
FAA and US first. ...
this may fall on various institutions ( like insurance companies, passengers ) balking.

From a communication point of view, it could be bad to return in service to close to the time where the JT610 will be published and debated everywhere in the media.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 10:32 am
by kayik
Don't forget to extend the page by "continue reading" , where it is explained how is this issue going to a dead-end.

https://www.moonofalabama.org/2019/09/b ... .html#more

But in a August 2019 meeting of international regulators Boeing failed to present them:

Friction between Boeing Co. and international air-safety authorities threatens a new delay in bringing the grounded 737 MAX fleet back into service, according to government and pilot union officials briefed on the matter.
The latest complication in the long-running saga, these officials said, stems from a Boeing briefing in August that was cut short by regulators from the U.S., Europe, Brazil and elsewhere, who complained that the plane maker had failed to provide technical details and answer specific questions about modifications in the operation of MAX flight-control computers.


As a consequence of Boeing's unwillingness EASA went public with its demands by putting them into the above presentation. Even under political pressure there is no way EASA can now go back on them.....

...Muilenberg does not seem to understand that Boeing has to do more about these issues than 'answer questions'...


Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 10:57 am
by morrisond
bennett123 wrote:
Several people have discussed whether the MCAS could have been disabled by the pilots, and what actions would have had this effect/the consequences of taking this action.

What I do not understand, is how any of this is relevant given that the pilots/airlines apparently did not know MCAS existed.


They did right after Lionair.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 11:04 am
by XRAYretired
'India plans to conduct its own checks and demand simulator training for all pilots before Boeing Co.’s 737 Max jets can fly in the country again, even if the U.S. Federal Aviation Administration were to clear the grounded jets, a person with direct knowledge of the matter said.'
https://www.bloomberg.com/news/articles ... 7-max-jets

Must be political in retaliation for Trump sanctions? (cos they cant have any one-upmanship intent, they don't have a large airplane manufacturer in country, any reason for not accepting Boeing/FAA certification without question). Or perhaps bribed by EU/China/Russia/Cocos Islands?

Ray

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 11:25 am
by par13del
I would only be concerned when smaller nations that have no aviation building infrastructure - say the Bahamas - start saying they need to clear the a/c first.
All these large nations have been taking on their own activities, wanting to be nuclear like the next guy, military like the next guy, sign joint agreements to build a/c and parts under license, but we are supposed to be shocked if they now say they want to do their own a/c certification?
I am still unsure why these nations still want / need or allow the FAA to rate their airport operations, one would think they would have given up on the FAA approval by now.
In any event, it is more news on the MAX front since it is almost the middle of September and Boeing is not saying much about the submission of their fixes to the FAA.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 11:54 am
by planecane
XRAYretired wrote:
'India plans to conduct its own checks and demand simulator training for all pilots before Boeing Co.’s 737 Max jets can fly in the country again, even if the U.S. Federal Aviation Administration were to clear the grounded jets, a person with direct knowledge of the matter said.'
https://www.bloomberg.com/news/articles ... 7-max-jets

Must be political in retaliation for Trump sanctions? (cos they cant have any one-upmanship intent, they don't have a large airplane manufacturer in country, any reason for not accepting Boeing/FAA certification without question). Or perhaps bribed by EU/China/Russia/Cocos Islands?

Ray


I will ask again, simulator training for what exactly? This question comes under the assumption that an AoA disagree will lead to an updated checklist that includes returning to the nearest suitable airport. I'm assuming this will be the case since an aircraft can't be dispatched with an AoA sensor failure so it would only be logical that an NNC wouldn't allow a continuation to destination with the same failure. With the AoA disagree warning present it should certainly be possible to ensure the aircraft stays out of the portion of the flight envelope where MCAS is needed.

Also, it seems that the most likely scenario for an AoA sensor failure is that either it was already broken before the takeoff roll or it is damaged by FOD or a bird shortly after takeoff. Flaps wouldn't have even been retracted yet. The NNC can include instructions to stay below flaps retraction speed and return to the airport. Aerodynamically, MCAS isn't required with flaps extended.

Final approach and landing would be the other likely damage scenario but flaps are likely extended at that point or will be very soon under a normal schedule. It seems that flying with MCAS disabled due to AoA disagree and ending up under the trigger conditions for it should be exceedingly rare. The only way I am wrong on this is if there is a history of a significant number of AoA sensor failures that happen at random times in cruise.

Therefore, if the only way to get an MCAS runaway (which with the limits of MCAS 2.0 will not lead to the same situation as the crashed flights) of any kind would be BOTH sensors failing within 5 degrees of each other with BOTH reading high AoA and if the chances of MCAS being required when it is disabled by an AoA disagree are extremely rare then what, exactly, is the good of simulator training?

It seems to me that, if my assumptions are correct, any demand for simulator training falls under the category of just "doing something" for PR and the sake of doing it. I can understand the desire for foreign regulators to do their own check since the FAA let MCAS 1.0 slip through. However, I think they should just pick one (EASA would be my vote) and the rest of the world should act on their results. If India can't trust EASA then doesn't that mean they must do their own certifications on all Airbus aircraft?

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:08 pm
by FluidFlow
planecane wrote:
XRAYretired wrote:
'India plans to conduct its own checks and demand simulator training for all pilots before Boeing Co.’s 737 Max jets can fly in the country again, even if the U.S. Federal Aviation Administration were to clear the grounded jets, a person with direct knowledge of the matter said.'
https://www.bloomberg.com/news/articles ... 7-max-jets

Must be political in retaliation for Trump sanctions? (cos they cant have any one-upmanship intent, they don't have a large airplane manufacturer in country, any reason for not accepting Boeing/FAA certification without question). Or perhaps bribed by EU/China/Russia/Cocos Islands?

Ray


I will ask again, simulator training for what exactly?


1. I expect general run-away trim recovery so that every future 737 Max pilot knows how to handle a run away trim no matter what caused it.
2. Reaction to multi-alarm situation caused by AoA sensor failure in critical flight stages including avoiding dangerous flight envelope areas
3. Flying and especially stall recovery with MCAS off due to AoA disagree.

Is it necessary? If we listen to Airbus and a lot of posters on this forum the quality of the training is not so good, so mandated sim training should be a good thing for general aviation safety.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:08 pm
by WIederling
morrisond wrote:
They did right after Lionair.

MCAS was mentioned.
( And that nice "RTFM" from Boeing. Daft third worlders no match to pilots at home.)
The wider implications such as limited trim wheel effectiveness, issues in data processing, ... were not known.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:12 pm
by WIederling
FluidFlow wrote:
Is it necessary? If we listen to Airbus and a lot of posters on this forum the quality of the training is not so good, so mandated sim training should be a good thing for general aviation safety.


I'd expect at least some sim training for the see saw technique of "overwhelming" the very high force "nigh blocked" manual trim wheel(s).

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:15 pm
by mjoelnir
morrisond wrote:
bennett123 wrote:
Several people have discussed whether the MCAS could have been disabled by the pilots, and what actions would have had this effect/the consequences of taking this action.

What I do not understand, is how any of this is relevant given that the pilots/airlines apparently did not know MCAS existed.


They did right after Lionair.


Could you point me to the information from Boeing, where they detailed MCAS and the working of it, after the Lion air crash?

If you mean pilots did know about MCAS by interference, that I would hardly call to know that MCAS existed, how it works and what the failure mode was.

All that pilots did know, was that a dangerous failure mode existed on the 737MAX that caused that frame to dive into the ground. The how, why and what, Boeing refused to explain.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:36 pm
by planecane
WIederling wrote:
FluidFlow wrote:
Is it necessary? If we listen to Airbus and a lot of posters on this forum the quality of the training is not so good, so mandated sim training should be a good thing for general aviation safety.


I'd expect at least some sim training for the see saw technique of "overwhelming" the very high force "nigh blocked" manual trim wheel(s).

Why? If MCAS 2.0 can't get into that condition and no runaway has done so on an NG why would it be good for pilots to spend valuable training time on it?

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 12:56 pm
by PixelFlight
planecane wrote:
XRAYretired wrote:
'India plans to conduct its own checks and demand simulator training for all pilots before Boeing Co.’s 737 Max jets can fly in the country again, even if the U.S. Federal Aviation Administration were to clear the grounded jets, a person with direct knowledge of the matter said.'
https://www.bloomberg.com/news/articles ... 7-max-jets

Must be political in retaliation for Trump sanctions? (cos they cant have any one-upmanship intent, they don't have a large airplane manufacturer in country, any reason for not accepting Boeing/FAA certification without question). Or perhaps bribed by EU/China/Russia/Cocos Islands?

Ray


I will ask again, simulator training for what exactly? This question comes under the assumption that an AoA disagree will lead to an updated checklist that includes returning to the nearest suitable airport. I'm assuming this will be the case since an aircraft can't be dispatched with an AoA sensor failure so it would only be logical that an NNC wouldn't allow a continuation to destination with the same failure. With the AoA disagree warning present it should certainly be possible to ensure the aircraft stays out of the portion of the flight envelope where MCAS is needed.

Also, it seems that the most likely scenario for an AoA sensor failure is that either it was already broken before the takeoff roll or it is damaged by FOD or a bird shortly after takeoff. Flaps wouldn't have even been retracted yet. The NNC can include instructions to stay below flaps retraction speed and return to the airport. Aerodynamically, MCAS isn't required with flaps extended.

Final approach and landing would be the other likely damage scenario but flaps are likely extended at that point or will be very soon under a normal schedule. It seems that flying with MCAS disabled due to AoA disagree and ending up under the trigger conditions for it should be exceedingly rare. The only way I am wrong on this is if there is a history of a significant number of AoA sensor failures that happen at random times in cruise.

Therefore, if the only way to get an MCAS runaway (which with the limits of MCAS 2.0 will not lead to the same situation as the crashed flights) of any kind would be BOTH sensors failing within 5 degrees of each other with BOTH reading high AoA and if the chances of MCAS being required when it is disabled by an AoA disagree are extremely rare then what, exactly, is the good of simulator training?

It seems to me that, if my assumptions are correct, any demand for simulator training falls under the category of just "doing something" for PR and the sake of doing it. I can understand the desire for foreign regulators to do their own check since the FAA let MCAS 1.0 slip through. However, I think they should just pick one (EASA would be my vote) and the rest of the world should act on their results. If India can't trust EASA then doesn't that mean they must do their own certifications on all Airbus aircraft?

I agree that simulator training is probably not required for MCAS V2, but simulator training could be required to recognize fast enough an AoA failure, and/or to use (small) trim wheels at high speed. I would prefer that the AoA disagree alert will be mandatory and that the trim wheels will be replaced by a backup trim switches connected to a backup electric motor powered by a backup power supply, like on the A350.

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Posted: Fri Sep 13, 2019 1:07 pm
by morrisond
PixelFlight wrote:
planecane wrote:
XRAYretired wrote:
'India plans to conduct its own checks and demand simulator training for all pilots before Boeing Co.’s 737 Max jets can fly in the country again, even if the U.S. Federal Aviation Administration were to clear the grounded jets, a person with direct knowledge of the matter said.'
https://www.bloomberg.com/news/articles ... 7-max-jets

Must be political in retaliation for Trump sanctions? (cos they cant have any one-upmanship intent, they don't have a large airplane manufacturer in country, any reason for not accepting Boeing/FAA certification without question). Or perhaps bribed by EU/China/Russia/Cocos Islands?

Ray


I will ask again, simulator training for what exactly? This question comes under the assumption that an AoA disagree will lead to an updated checklist that includes returning to the nearest suitable airport. I'm assuming this will be the case since an aircraft can't be dispatched with an AoA sensor failure so it would only be logical that an NNC wouldn't allow a continuation to destination with the same failure. With the AoA disagree warning present it should certainly be possible to ensure the aircraft stays out of the portion of the flight envelope where MCAS is needed.

Also, it seems that the most likely scenario for an AoA sensor failure is that either it was already broken before the takeoff roll or it is damaged by FOD or a bird shortly after takeoff. Flaps wouldn't have even been retracted yet. The NNC can include instructions to stay below flaps retraction speed and return to the airport. Aerodynamically, MCAS isn't required with flaps extended.

Final approach and landing would be the other likely damage scenario but flaps are likely extended at that point or will be very soon under a normal schedule. It seems that flying with MCAS disabled due to AoA disagree and ending up under the trigger conditions for it should be exceedingly rare. The only way I am wrong on this is if there is a history of a significant number of AoA sensor failures that happen at random times in cruise.

Therefore, if the only way to get an MCAS runaway (which with the limits of MCAS 2.0 will not lead to the same situation as the crashed flights) of any kind would be BOTH sensors failing within 5 degrees of each other with BOTH reading high AoA and if the chances of MCAS being required when it is disabled by an AoA disagree are extremely rare then what, exactly, is the good of simulator training?

It seems to me that, if my assumptions are correct, any demand for simulator training falls under the category of just "doing something" for PR and the sake of doing it. I can understand the desire for foreign regulators to do their own check since the FAA let MCAS 1.0 slip through. However, I think they should just pick one (EASA would be my vote) and the rest of the world should act on their results. If India can't trust EASA then doesn't that mean they must do their own certifications on all Airbus aircraft?

I agree that simulator training is probably not required for MCAS V2, but simulator training could be required to recognize fast enough an AoA failure, and/or to use (small) trim wheels at high speed. I would prefer that the AoA disagree alert will be mandatory and that the trim wheels will be replaced by a backup trim switches connected to a backup electric motor powered by a backup power supply, like on the A350.


Sim time is needed by all Pilots to ensure they can fly with Manual Throttle/Manual trim and all the Nannies turned off. It should be a non-event for all Pilots to fly the aircraft they are certified on even in IMC conditions using full manual control 100% of the time and practiced regularly so if HAL tries to kill them it's a non-event to turn all the helpers off.

Otherwise you might as well just get rid of the pilots and just accept HAL crashes every now and then which thankfully are getting fewer and fewer but will never go to zero as we will never be able to anticipate every situation or failure that the computers will have to deal with.