LJ
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 6:45 am

LDRA wrote:
Who did the worst case analysis for computation resources? Why is this scenario not covered by worst case analysis?


Let's be realistic. It's very difficult to predict each possible worst case which could arise and thus no test will ever cover 100% of all possible (worst) cases. That's why we have somebody else look at it from a different perspective and thus increase the likelihood that the test covers more situations. Yes, Boeing needs to analyse why they didn't discover this issue, but we shouldn't demand the impossible from Boeing. We must be glad that the issue was discovered by the FAA and thus that the safety system worked. Moreover, I'm sure the regulators will also ask Boeing to explain why they missed this and asses if this is an issue. Then again, some on this board will never trust the regulators and thus will always be very skeptical should the MAX be approved to fly one day.
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 6:57 am

MSPNWA wrote:
PW100 wrote:
You are not addressing my point. The point was that the certification system should (have) demonstrate(d) that the design was safe. Of course one can debate to death what constitutes as safe, but fact is that the two crashes revealed serious issues (MCAS 1.0) which that certification system was unable to detect. So it is very obvious that the first thing after correcting MCAS, is the question if there are perhaps other issues might have that escaped through the very same certification system. That is not politics, but engineering 101. And just in case, for those binary minds: please note that this is not claiming the thing is unsafe and that there must be other issues.

Further I never claimed any sort of "standard for safety" in my message (it was brought up by yourself). It is beyond me why you would bring that up and turn that into something against me claiming that "would mean no new airplane would ever take to the skies".


Oh I got your point. I just pointed out how it was irrational. The plane is grounded because of two crashes. It isn't grounded because something was found regarding certification.

If you want to keep it grounded until it proves the unprovable, that's a different point. I recommend making that point before you expect someone to address it.

And oh, yes, you positively made a "standard for safety" inference that would mean no new or grounded airplane would ever take to your skies.


There ARE standards for embedded code design for all kind of safety critical systems (e.g. car engine controllers). There are also standards for software testing (outside of safety critical designs, but apply to those too). It is well known that testing the buggy code in real world is unlikely to reveal fatal flaws, since there are too many code paths to test in end-to-end testing. But this does not meant that the code cannot be tested. This is pretty easy task if the code is written with standards and modularity and testing in mind.

If it is not (like the Toyota Camry MCU code - spaghetti code) then there is no way to test it. Has to be written anew. I suspect that at least some modules are now being feverishly rewritten by Boeing due to code being found that the code is untestable.

Any serious flaw that comes to the point that is revealed in simulator is extremely serious deal. That means it escaped all the safeguards described above.
 
Freefall
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 6:58 am

freakyrat wrote:
What the FAA Test Pilots have found in the simulator is that even with the software fix there isn't enough computing power in the microprocessor unit for MCAS for the pilots to recover from a runaway horizontal stabilizer situation quickly enough. So Boeing will have to go back to the drawing board and design and install a more robust microprocessor unit in MCAS in each grounded aircraft active and the ones that are undelivered.

So not only did Boeing desgn a faulty system but also they put in a microprocessor unit to control it that did not have enough computing power to keep up with it. This essentially hung the pilots out to dry when MCAS went beserk. Personally I feel this is a major setback for Boeing as the FAA is not going to allow this aircraft back in the air until this is all corrected which could mean sometime next year.

This also doesn't even begin to address the training issues.
aryonoco wrote:
AirlineCritic wrote:
I came here to read about the issues recently discovered per various news sites, to see how they might affect return to flight. But what found was continued tirade



+1

So based on my understanding of the news reports, the new issue seems to not be directly related to MCAS. It was discovered by a FAA test pilot. Boeing acknowledges the issue. We don't yet know if the new issue requires a software or a hardware fix.

Even if the new issue can be fixed by just software, it needs further validation and testing. Personally I'm sure Boeing will eventually fix the issues, but I don't see the MAX back in service this year. And what kind of pilot training will be needed after all these software alterations is also a separate discussion.
I think they will need change both (software and hardware) upgrades probably needed because now MCAS software needs to deal with more situations/scenarios and for that more processing power and memory will be needed.

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Armodeen
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:02 am

They are NOW anyway!

planecane wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

Can we now put the myth to rest that the FAA is just rubber stamping whatever Boeing says? Clearly there is real testing and analysis by the FAA.
 
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JerseyFlyer
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:04 am

Are they still safe to fly off the production line into storage? If I were a pilot doing that every day, I would now be worried.
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:06 am

ArgentoSystems wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

That is weird. Did not they test the hell out of the fixed system before inviting "government pilots" for a test drive? That is unsurpassed level of lameness if it is true. I'm having hard time believing it. But then again, I also could not believe how badly MCAS 1.0 was implemented.


I would say this has become Pandora's box. After MCAS 1.0 all the code was subject to review, either by FAA or internally by Boeing. The only explanation for the long delay in releasing the MCAS 2.0 could be that code is a mess (not Toyota-level mess, but nevertheless a mess regarding the strict safety requirements for airplanes) so far untestable. So perhaps large swaths of the code have to be written from scratch before it could even be properly tested. In that scenario I would not be surprised if someone at Boeing got the idea to invite "government pilots" to test the plane with the old code with some kind of quick fix, for the PR purposes. Obviously it backfired.

I mean i HOPE that was the old code. Not the code for which Boeing said "there, this has been tested now".
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:08 am

lightsaber wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

Rhoo rhoo

Fault testing is interesting. Double faults must be tested in the lab/flight simulator. It sounds like one was found.


Question is, why this test was not done by Boeing before putting MAX into the service? Or, why this flaw was not found before putting MAX into the service? Perhaps even Boeing did not have accurate MAX simulators at the time when they released the plane into service (this is a horrible thought).
 
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aerolimani
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:22 am

LJ wrote:
LDRA wrote:
Who did the worst case analysis for computation resources? Why is this scenario not covered by worst case analysis?


Let's be realistic. It's very difficult to predict each possible worst case which could arise and thus no test will ever cover 100% of all possible (worst) cases.


Of course, it's impossible to predict. That's what testing is for! With a simulator, assuming it's accurate, you should be able to get pretty damned close to 100%.

LJ wrote:
That's why we have somebody else look at it from a different perspective and thus increase the likelihood that the test covers more situations. Yes, Boeing needs to analyse why they didn't discover this issue, but we shouldn't demand the impossible from Boeing. We must be glad that the issue was discovered by the FAA and thus that the safety system worked. Moreover, I'm sure the regulators will also ask Boeing to explain why they missed this and asses if this is an issue. Then again, some on this board will never trust the regulators and thus will always be very skeptical should the MAX be approved to fly one day.


I'm sorry, but we should absolutely expect Boeing to find all the possible problems. They're the ones earning the record profits, so surely they can afford it. Besides, I think it's in their best interest to manufacture the safest possible plane. Is it not?

The regulators should be there to provide a backup. Of course, they should absolutely be stringent and effective, and the manufacturers' goal ought to be that the regulators never find a problem.

Can we maybe stop trying to let Boeing off the hook? They need to own this, and they need to fix both the MAX and the company.
 
Wallhart
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:31 am

Is there an investigation on the ongoings of Boeing processes internally?

I mean there are some other angles to this.

1. Was the negligence involved? Were these concerns raised and purposefully dismissed to meet date and cost targets etc. Can we expect cased to be brought against the execs. Actually sorry what was I thinking, I mean middle management as they will be escape goats.

2. Are the processes for for purpose. Strategy is set from the top and if the strategy has led to weaknesses which has led to these deaths then the board must seriously be considering positions at the top.

Apologies if these have been answered. Im a bit behind on the politics of this

Boeing have made beautiful safe planes for decades so something has gone seriously wrong.
 
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JerseyFlyer
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:45 am

Is a fair deduction from this latest news that the crashed aircraft may have been irrecoverable, whatever the pilots did, because the computer "hung". My layman's language, obviously.
 
marcelh
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 7:57 am

JerseyFlyer wrote:
Is a fair deduction from this latest news that the crashed aircraft may have been irrecoverable, whatever the pilots did, because the computer "hung". My layman's language, obviously.

Gives a whole new meaning at the phrase “blue screen of death” :shock:
 
PANAMsterdam
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:00 am

Hello Airliner friends! Longtime Airliners.net reader, but this is my first post here :)

The whole 737Max drama saddens me on one hand and shocks me on the other hand. I have been a long time Boeing fan (but no Airbus hater, please let's be friendly with each other) but the mistakes they made with the rushed introduction of the Max are indefensible and hope will never be made again.

I saw this video of Boeing's Renton factory, where they are even parking brand new 737's on the employee parking lots (at 1:35) because they have completely ran out of regular aircraft parking space. That tells you a lot about how long this grounding has been going on. Hope the will wrinkle out every microscopic tiny flaw they can find so that the Baby Boeing can live a long and prosperous life once she takes off again. :)
Come fly with me, let's fly, let's fly away!
 
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FabDiva
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:17 am

Strato2 wrote:
AeroplaneFreak wrote:

Yes there will plenty of media coverage of people refusing to fly it when it returns to service but this is nothing new. We saw it with the A380 and B787 when they had their respective incidents all be it those incidents didn't reach the level of the MAX but they came close.


What incidents exactly has the A380 had. None. It had one engine failure that was the fault of RR. These kind of failures have happened to planes like the 767. Nothing ever was wrong with the airframe or its design. In contrast the 787 was grounded like the Max.


I think they were referring to the cracking found as part of that investigation. Also if that engine failure had brought the aircraft down then most people would associate it with the aircraft rather then the engine and rightly questions would be asked about how Airbus could have let an engine failure bring a plane down. Thankfully the aircraft landed safely so we are not in that position
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:33 am

aryonoco wrote:
AirlineCritic wrote:
I came here to read about the issues recently discovered per various news sites, to see how they might affect return to flight. But what found was continued tirade



+1

So based on my understanding of the news reports, the new issue seems to not be directly related to MCAS. It was discovered by a FAA test pilot. Boeing acknowledges the issue. We don't yet know if the new issue requires a software or a hardware fix.

Even if the new issue can be fixed by just software, it needs further validation and testing. Personally I'm sure Boeing will eventually fix the issues, but I don't see the MAX back in service this year. And what kind of pilot training will be needed after all these software alterations is also a separate discussion.
The problem is that the processor is an old one that does not appear to have enough power to run more complex time critical calculations. The processor cannot be easily changed. The process to do so would take years since they are tested so thoroughly. You change the processor and ask the code has to be retested from to to bottom.

It may be possible to optimise the code use less CPU resources but that will also take signficant time.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:36 am

xmp125a wrote:
lightsaber wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

Rhoo rhoo

Fault testing is interesting. Double faults must be tested in the lab/flight simulator. It sounds like one was found.


Question is, why this test was not done by Boeing before putting MAX into the service? Or, why this flaw was not found before putting MAX into the service? Perhaps even Boeing did not have accurate MAX simulators at the time when they released the plane into service (this is a horrible thought).


$$$$$ and a lack of respect for what it takes to do proper engineering.
 
packsonflight
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:44 am

Lot of discussion here about single AOA sensor input and the risk of that single AOA sensor failure with possible fatal consequences, and no attention has bin given to the fact that the MCAS system is in it self a single system architecture. What happens if this single MCAS system fails? That is what I think is going on here.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:44 am

MSPNWA wrote:
PW100 wrote:
You are not addressing my point. The point was that the certification system should (have) demonstrate(d) that the design was safe. Of course one can debate to death what constitutes as safe, but fact is that the two crashes revealed serious issues (MCAS 1.0) which that certification system was unable to detect. So it is very obvious that the first thing after correcting MCAS, is the question if there are perhaps other issues might have that escaped through the very same certification system. That is not politics, but engineering 101. And just in case, for those binary minds: please note that this is not claiming the thing is unsafe and that there must be other issues.

Further I never claimed any sort of "standard for safety" in my message (it was brought up by yourself). It is beyond me why you would bring that up and turn that into something against me claiming that "would mean no new airplane would ever take to the skies".


Oh I got your point. I just pointed out how it was irrational. The plane is grounded because of two crashes. It isn't grounded because something was found regarding certification.

If you want to keep it grounded until it proves the unprovable, that's a different point. I recommend making that point before you expect someone to address it.

And oh, yes, you positively made a "standard for safety" inference that would mean no new or grounded airplane would ever take to your skies.


OK. Sure, the planbe was grounded because of two major accidents in short succession.
The accidents were a direct result of "issues with certification". If you want to stop the grounding, you have to fix the certification issues. And those issues are not MCAS itself; MCAS is just the sympton of issues, not the root cause.

Respectfully, can you quote my tekst where I made a "standard for safety"?
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JerseyFlyer
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:45 am

RickNRoll wrote:
The problem is that the processor is an old one that does not appear to have enough power to run more complex time critical calculations. The processor cannot be easily changed. The process to do so would take years since they are tested so thoroughly. You change the processor and ask the code has to be retested from to to bottom.

It may be possible to optimise the code use less CPU resources but that will also take signficant time.


Is there really only one processor inputting to control surface movements? I recall when FBW was a new concept on A320s and Airbus reassured those concerned that there would always be 3 to ensure the necessary redundancy
 
StTim
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:52 am

JerseyFlyer wrote:
RickNRoll wrote:
The problem is that the processor is an old one that does not appear to have enough power to run more complex time critical calculations. The processor cannot be easily changed. The process to do so would take years since they are tested so thoroughly. You change the processor and ask the code has to be retested from to to bottom.

It may be possible to optimise the code use less CPU resources but that will also take signficant time.


Is there really only one processor inputting to control surface movements? I recall when FBW was a new concept on A320s and Airbus reassured those concerned that there would always be 3 to ensure the necessary redundancy


As we know the 737 is not a FBW architecture. It has had progressively functions bolted on. I suspect that what happened was processor overload rather than BSOD type failure. The problem there is re writing software to be less processor hungry is time consuming and can introduce additional new unexpected features (read bugs). The more extensive the code changes needed to more testing that will be required.
 
goosebayguy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:55 am

Apparently the latest testing has failed. Boeing have accused the test pilot on trying too hard to get MCAS to fail and it has. Only in the sense that it took too long to recover. So AA And Southwest have put back introduction for another month.

Beoing has to appreciate that they have to get this right. A further crash will destroy Boeing. Why are they not taking safety seriously?
 
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keesje
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 8:57 am

I think for these flight control, stabelizing, trimming systems on the MAX, the pilots must take care for a lot of the redundancy. They have a lot to monitor, (de) activate systems, manually intervene. Little system redundancy in some areas. During emergency situations that's adds up to the workload. It's certification might have to do with grandfathered systems and interface requirements, valid at the time previous 737 versions were certified. Plus the drive to keep maximal commonality with the NG / avoid extra training requirements despite changes like MCAS.
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giblets
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:00 am

goosebayguy wrote:
Apparently the latest testing has failed. Boeing have accused the test pilot on trying too hard to get MCAS to fail and it has. Only in the sense that it took too long to recover. So AA And Southwest have put back introduction for another month.

Beoing has to appreciate that they have to get this right. A further crash will destroy Boeing. Why are they not taking safety seriously?


Did Boeing really think the regs body would take their word again, they are nuts if that’s the case.
Both Boring and the FAA need to gain the confidence of the worlds airlines and authorities, and if this story is shown to be true, it’s shows that only one these is doing their best to regain that trust.


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XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:00 am

Bit more of a technical description here. Love the vernacular use in the first part. It would be useful to know how the pilots/simulator recovered e.g. did they just wait for the processor to sort itself out or was there some reset performed?

'It's understood the code that knackered the hardware was part of a firmware update to address deadly flaws in MCAS, the 737 Max's anti-stall tech that wound up killing hundreds of people.

To us, it sounds as though code in the MCAS update either forces the processor into a locked state, such as a tight unbreakable and uninterruptable infinite loop, or triggers an exception that can't be handled and the CPU halts. It is remotely possible the code encounters a design flaw in the unidentified microprocessor that causes the circuitry to freeze.'
https://www.theregister.co.uk/2019/06/2 ... bug_found/

Ray
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:01 am

c933103 wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

Does that mean they will need to physically replace all the flight control computers in existing aircrafts?


As I understood (may be wrong) it is an issue how the system handles the particular hardware failure. So it may be a software problem (hardware failures are inevitable!).
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:05 am

JerseyFlyer wrote:
Is a fair deduction from this latest news that the crashed aircraft may have been irrecoverable, whatever the pilots did, because the computer "hung". My layman's language, obviously.


Given that it is not a FBW plane, are we again at the same old MCAS story? Plane that IS FLYABLE getting crashed by electronics (which is not up to FBW redundancy standards, because it does not have to be, since there exist mechanical/hydraulical connections between the pilot and the flying surfaces?)
 
AirwayBill
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:20 am

goosebayguy wrote:
Apparently the latest testing has failed. Boeing have accused the test pilot on trying too hard to get MCAS to fail and it has.


Not sure if we should laugh or cry about this. The point of any decent testing program is to put a product at 300% the conditions it would normally face.

Boeing's delusional management needs a serious reality check, in fact I cannot believe that most people in charge of the beginning of the MAX crisis are still in in place. This shows that they have no will whatsoever to learn from their mistakes.

Agrajag wrote:
I wonder what meaningless lawyer led weasel words will will hear from Boeing management today?


Same here, popcorn is out and ready :checkmark: :checkmark: :checkmark:
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:20 am

JerseyFlyer wrote:
RickNRoll wrote:
The problem is that the processor is an old one that does not appear to have enough power to run more complex time critical calculations. The processor cannot be easily changed. The process to do so would take years since they are tested so thoroughly. You change the processor and ask the code has to be retested from to to bottom.

It may be possible to optimise the code use less CPU resources but that will also take signficant time.


Is there really only one processor inputting to control surface movements? I recall when FBW was a new concept on A320s and Airbus reassured those concerned that there would always be 3 to ensure the necessary redundancy
They probably have more than one processor, but they run in parallel to provide redundancy. Just as two AoA sensors don't make the AoA reading more accurate. They just make it more reliable.
 
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crimsonchin
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:22 am

Basically another potentially fatal fault was discovered unrelated to the MCAS issue that was being tested for and this fault has also been there from the start?

The NEO and that huge AA order really did a number on their psyche.
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:26 am

MSPNWA wrote:
But you just inferred that apparently proper certification isn't enough.

A proper certification certainly is enough. But certifying a failed design can't be called a proper certification. It must be called failed certification.

speedking wrote:
Today a planes safety is not determined by miles flown but posts in social media.

In this case both "evidences" are in agreement.

The noise and upset in social matches the abyssal safety record of the MAX. Two crashes in two years after EIS have not been seen anymore since the 1960s. And even unprecedented are two crashes due to the same technical cause with that rate.

Every seventh 737 would have crashed, if the whole 737 family would have the same safety record as the MAX (2 crashes / 516k flight hours => 1056 crashes / 264 million flight hours, stats from 2014).

planecane wrote:
The fact remains that the MAX didn't "fall out of the sky," "commit suicide," "crash itself" or any of the other things people like to post in this thread to be overly dramatic.

The fact is, that two times a system in a plane commanded an unrecoverable final dive into the ground. All of your "summaries" are correct therefore.
Many things are difficult, all things are possible!
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:36 am

crimsonchin wrote:
Basically another potentially fatal fault was discovered unrelated to the MCAS issue that was being tested for and this fault has also been there from the start?


Apparently, the bug was in the NEW code, which was developed as a fix for MCAS!

https://www.theregister.co.uk/2019/06/2 ... bug_found/

The US manufacturer on Wednesday confirmed that, during simulator tests on the embattled jetliners, the 737 Max's new control software would lock up a microprocessor resulting in the plane automatically entering a dangerous nosedive. It's understood the code that knackered the hardware was part of a firmware update to address deadly flaws in MCAS,

This means exactly I was saying 2 months ago. It is not MCAS problem, it is a Boeing problem, they simply cannot develop safety critical code up to standards. Whether this is due to lack of experienced engineers (who left, retired, or have been forced out because they were pesky enough with safety issues), we don't know. But FAA should really look at the processes inside Boeing now.
 
Interested
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:39 am

AirwayBill wrote:
goosebayguy wrote:
Apparently the latest testing has failed. Boeing have accused the test pilot on trying too hard to get MCAS to fail and it has.


Not sure if we should laugh or cry about this. The point of any decent testing program is to put a product at 300% the conditions it would normally face.

Boeing's delusional management needs a serious reality check, in fact I cannot believe that most people in charge of the beginning of the MAX crisis are still in in place. This shows that they have no will whatsoever to learn from their mistakes.

Agrajag wrote:
I wonder what meaningless lawyer led weasel words will will hear from Boeing management today?


Same here, popcorn is out and ready :checkmark: :checkmark: :checkmark:


I refuse to believe a Boeing official has actually said the above about a test pilot trying too hard to get MCAS to fail?

Is there a link to anything official?
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:43 am

Few points.

1. Obviously I don't know exactly what is going on with most recent issue, but am very surprised that its not scheduled in timely fashion as MCAS calculations should be quite trivial. Better for Boeing if it is associated to signal processing rather than stability and control.
2. Boeing cannot realistically change the computing hardware within 24 months. They would have to re-certify the whole architecture (S/W and H/W). That would be an absolute nightmare scenario.
3. Usually, some fat can be trimmed from various procedures and/or the scheduler adjusted move the procedures(s) in question to a higher priority.
4. There could be a hang-up in other procedures that are finding themselves in a bit of a corner within the parameter envelope that also activates MCAS and are thus churning away CPU cycles.
5. Doesn't look good. For FAA or Boeing. That is two problems now with symptoms in the same subsystem that have found their way through the net. While you can never prove a negative, finding two positive fails in such a small area of the aircraft design is concerning.
 
xmp125a
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:50 am

Amiga500 wrote:
2. Boeing cannot realistically change the computing hardware within 24 months. They would have to re-certify the whole architecture (S/W and H/W). That would be an absolute nightmare scenario.


Let's take a step back.Remember when everyone were shaking their heads how on Earth MCAS V1.0 found its way to production?

A bit of conspiracy teory, but plausible one: what if "proper" MCAS design was tested during MAX development but found to be too demanding for the flight computer? And then MCAS 1.0 with its fatal flaws was born, and seemingly stupid design decisions, like use 1 sensor only, alternate sensor between the flights?

Is that really out of the question?
 
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keesje
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:51 am

What nobody (including the press) dares to discuss, order cancellations.

Garuda has already cancelled its order. Other airlines such as Lion Air, Kenya Airways, Vietjet Airlines, Azerbaijan Airlines, Flydubai and Icelandair are also playing with the idea of doing the same and maybe even be switching to Airbus.

https://www.aerotelegraph.com/en/flyadeal-did-boeing-lose-another-order-for-737-max-to-airbus
"Never mistake motion for action." Ernest Hemingway
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:53 am

Incidentally, The Aspen Times had a full article yesterday about 'firings' and 'heads rolling' at Boeing and referencing Boeing CEO as source. This seems to have been taken down and replaced with a one liner.

'Muilenburg said the company has made personnel changes since the crashes, but he would not provide specifics.'
https://www.aspentimes.com/news/local/b ... pen-crowd/

Ray
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 9:58 am

xmp125a wrote:
Amiga500 wrote:
2. Boeing cannot realistically change the computing hardware within 24 months. They would have to re-certify the whole architecture (S/W and H/W). That would be an absolute nightmare scenario.


Let's take a step back.Remember when everyone were shaking their heads how on Earth MCAS V1.0 found its way to production?

A bit of conspiracy teory, but plausible one: what if "proper" MCAS design was tested during MAX development but found to be too demanding for the flight computer? And then MCAS 1.0 with its fatal flaws was born, and seemingly stupid design decisions, like use 1 sensor only, alternate sensor between the flights?

Is that really out of the question?


Ah, nah, can't really believe that.

Trying to do that would leave a paper trail - which would have ended up in folks being prosecuted before now.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:02 am

PixelFlight wrote:
planecane wrote:
trini81 wrote:
https://edition.cnn.com/2019/06/26/politics/boeing-737-max-flaw/index.html

Havent seen it posted before... it seems a New flaw discovered on Boeing 737 Max.
"In simulator tests, government pilots discovered that a microprocessor failure could push the nose of the plane toward the ground. It is not known whether the microprocessor played a role in either crash.
When testing the potential failure of the microprocessor in the simulators, "it was difficult for the test pilots to recover in a matter of seconds," one of the sources said. "And if you can't recover in a matter of seconds, that's an unreasonable risk."

Can we now put the myth to rest that the FAA is just rubber stamping whatever Boeing says? Clearly there is real testing and analysis by the FAA.

"FAA is just rubber stamping whatever Boeing says" was the case before the grounding, including the EAD. The best proof is precisely that now that "real testing and analysis by the FAA" are in place there discover multiple issues. This fully demonstrate that the main cause was bad safety activities inside Boeing.

I'm not talking about that. There have been many accusations in this thread that the FAA is rubber stamping the ungrounding and that's why the rest of the world's aviation authorities shouldn't unground in sync with the FAA.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:09 am

xmp125a wrote:
crimsonchin wrote:
Basically another potentially fatal fault was discovered unrelated to the MCAS issue that was being tested for and this fault has also been there from the start?


Apparently, the bug was in the NEW code, which was developed as a fix for MCAS!

https://www.theregister.co.uk/2019/06/2 ... bug_found/

The US manufacturer on Wednesday confirmed that, during simulator tests on the embattled jetliners, the 737 Max's new control software would lock up a microprocessor resulting in the plane automatically entering a dangerous nosedive. It's understood the code that knackered the hardware was part of a firmware update to address deadly flaws in MCAS,

This means exactly I was saying 2 months ago. It is not MCAS problem, it is a Boeing problem, they simply cannot develop safety critical code up to standards. Whether this is due to lack of experienced engineers (who left, retired, or have been forced out because they were pesky enough with safety issues), we don't know. But FAA should really look at the processes inside Boeing now.


Exactly. MCAS was just the symptom, not the root cause. To lift the grounding, the root cause must be fixed not (just) the symptom(s)

The fact that this issue was observed so late in the process and not even by Boeing themselves, *knowing that they would be really under the microsope for MCAS 2.0*, is a real disaster for trust in their engineering, quality and "self-certificate" processes.

At the same time, it is a good start for FAA to regain some of their own lost trust . . .
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:12 am

rheinwaldner wrote:
planecane wrote:
The fact remains that the MAX didn't "fall out of the sky," "commit suicide," "crash itself" or any of the other things people like to post in this thread to be overly dramatic.

The fact is, that two times a system in a plane commanded an unrecoverable final dive into the ground. All of your "summaries" are correct therefore.


The "final dive" may or may not have been recoverable. Nobody has tested that because it doesn't really matter. The recovery from the situation was possible (as evidenced by Lion Air 043) BEFORE it got to the final nose dive.

The adjectives that I used above are overly dramatic and would only be accurate if the situation that occurred was unrecoverable. It wasn't. MCAS created an emergency situation. The bad design of MCAS caused this situation to happen at an unacceptably high rate. The crashes happened because there was a lack of documentation from Boeing and inadequate training (both as the result of the lack of documentation and because runaway stabilizer seems to be exceedingly rare outside of MCAS) so that two crews did not perform the relatively simple steps that would have recovered. To use those descriptions means that Lion air 043 would have also crashed because they imply that the situation was unrecoverable.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:33 am

XRAYretired wrote:
Bit more of a technical description here. Love the vernacular use in the first part. It would be useful to know how the pilots/simulator recovered e.g. did they just wait for the processor to sort itself out or was there some reset performed?

'It's understood the code that knackered the hardware was part of a firmware update to address deadly flaws in MCAS, the 737 Max's anti-stall tech that wound up killing hundreds of people.

To us, it sounds as though code in the MCAS update either forces the processor into a locked state, such as a tight unbreakable and uninterruptable infinite loop, or triggers an exception that can't be handled and the CPU halts. It is remotely possible the code encounters a design flaw in the unidentified microprocessor that causes the circuitry to freeze.'
https://www.theregister.co.uk/2019/06/2 ... bug_found/

Ray


The Guardian article seems to say very different things than the CNN article which the Guardian article seems to be using as the source. The CNN article seems to indicate that a scenario was tested based on FAA input to determine what would happen IF a microprocessor failed. The result was that if there was a failure it could result in uncommanded nose down trim. The article then states that Boeing engineers are evaluating how to mitigate the risk. Nowhere does the CNN article state or imply that the software locked up a microprocessor.

On the other hand, the Guardian article says that the software "would lock up a microprocessor." It does not pass the common sense test that this didn't happen in weeks of Boeing internal testing or that it did happen and they just let the FAA evaluate it anyway. The Guardian then states the following:

The US manufacturer on Wednesday confirmed that, during simulator tests on the embattled jetliners, the 737 Max's new control software would lock up a microprocessor resulting in the plane automatically entering a dangerous nosedive.


There is no supporting quote for this statement. By saying the US manufacurer "confirmed" indicates an official statement, not an anonymous source. The offical statement from Boeing is:

The safety of our airplanes is Boeing’s highest priority. During the FAA’s review of the 737 MAX software update and recent simulator sessions, the Federal Aviation Administration (FAA) identified an additional requirement that it has asked the company to address through the software changes that the company has been developing for the past eight months. The FAA review and process for returning the 737 MAX to passenger service are designed to result in a thorough and comprehensive assessment. Boeing agrees with the FAA's decision and request, and is working on the required software. Addressing this condition will reduce pilot workload by accounting for a potential source of uncommanded stabilizer motion. Boeing will not offer the 737 MAX for certification by the FAA until we have satisfied all requirements for certification of the MAX and its safe return to service.


Where does that remotely confirm that the "new control software would lock up a microprocessor?" The fact that the official statement says "accounting for a potential source of uncommanded stabilizer motion" makes it line up with the CNN reporting that the FAA identified a potential cause of runaway stabilizer.

My bigger concern is whether this potential cause exists on the NG as well. Since MCAS appears to be an extension of the STS code, is the same microprocessor and interface design used on the NG and can it cause a runaway stabilizer? If yes, is this just a case of the FAA being overly cautious about the MAX and making sure to cover every possible cause of runaway stabilzier even if it is exceedingly rare or unlikely?

I would put the brakes on drawing conclusions based on the Guardian article. It looks to me like they took the CNN article and embelished it for drama and clicks but may have created some "fake news" on top of the real facts reported by CNN.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:40 am

BoeingVista wrote:
Revelation wrote:
Gordon Johndroe, a Boeing spokesman, said the company agreed with the FAA finding and was addressing the issue as well as a broader software redesign that’s been underway for eight months.

Looks like I was on target when I suggested it could very well be addressed via software, but "broader software redesign" "underway for eight months" is also not a good thing to be dropping on people right about now.

I disagree with that assessment its quite possible that Boeing has just run out of processing power for the amount of tasks the computer is required to perform.

It may be fixable in software if they are lucky but eventually a system will run out of processing power and that needs a hardware fix, try booting windows 10 on a computer from 2000. The closer you get to using all of your computing capacity the less reliable timings become, and fancy programming to trim times processing normal routine actions can create bigger lags with edge case issues.

We are both using indefinite adjectives, i.e. we're both not saying we know the answer for sure.

Note my original post was in the context of the supposition that the issue was in the 'microprocessor unit' meant the 'microprocessor unit' needed to be replaced, which still is an unknown, and the Bloomberg report was the first one to raise the issue of a software redesign being evaluated.

downdata wrote:
The thing is... if you have a software in your plane that flies it into the ground by itself... its going to be inadvertently triggered somehow unless you can prevent the infinite number of possibilities that can cause the system to fail ...

I have a graduate degree in computer science, and guess what, there effectively are an infinite number of possibilities and testing cannot cover them all. There was a lot of work in the 70s on "provably correct" programs (one example is the software that is in the space shuttle flight computer) but industry walked away from that because it was such expensive and special purpose stuff.

RickNRoll wrote:
So based on my understanding of the news reports, the new issue seems to not be directly related to MCAS. It was discovered by a FAA test pilot. Boeing acknowledges the issue. We don't yet know if the new issue requires a software or a hardware fix.

That is my understanding as well.

RickNRoll wrote:
Even if the new issue can be fixed by just software, it needs further validation and testing. Personally I'm sure Boeing will eventually fix the issues, but I don't see the MAX back in service this year. And what kind of pilot training will be needed after all these software alterations is also a separate discussion.

The problem is that the processor is an old one that does not appear to have enough power to run more complex time critical calculations. The processor cannot be easily changed. The process to do so would take years since they are tested so thoroughly. You change the processor and ask the code has to be retested from to to bottom.

It may be possible to optimise the code use less CPU resources but that will also take signficant time.

We don't know where they are on that timeline, if I am reading Bloomberg's "software redesign taking eight months" quote correctly.

XRAYretired wrote:
Bit more of a technical description here. Love the vernacular use in the first part. It would be useful to know how the pilots/simulator recovered e.g. did they just wait for the processor to sort itself out or was there some reset performed?

'It's understood the code that knackered the hardware was part of a firmware update to address deadly flaws in MCAS, the 737 Max's anti-stall tech that wound up killing hundreds of people.

To us, it sounds as though code in the MCAS update either forces the processor into a locked state, such as a tight unbreakable and uninterruptable infinite loop, or triggers an exception that can't be handled and the CPU halts. It is remotely possible the code encounters a design flaw in the unidentified microprocessor that causes the circuitry to freeze.'
https://www.theregister.co.uk/2019/06/2 ... bug_found/

Ray

It seems like The Register, a delightfully dodgy tech news site, is interpreting things differently than Bloomberg and blurring a line that Bloomberg made clear, that while the problem is indeed a part of the new firmware being tested, it is not due to the MCAS fix itself, which may or may not broaden or lessen the scope of the issue depending on your view point.

[Edits: formatting]
Last edited by Revelation on Thu Jun 27, 2019 10:59 am, edited 3 times in total.
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kayik
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:43 am

Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?
 
yabeweb
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:55 am

kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?

At this point.... anything is possible.
 
SEU
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:57 am

kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?


Could very well be.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 10:59 am

kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?

The old saying is there are no stupid questions. Absolutely, the FAA is working with Boeing to find an issue that will cause a delay of weeks or months as a PR stunt.
 
yabeweb
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 11:02 am

planecane wrote:
kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?

The old saying is there are no stupid questions. Absolutely, the FAA is working with Boeing to find an issue that will cause a delay of weeks or months as a PR stunt.

Yeah.. who would suspect that right??

Also, make it sounds stupid and impossible, and people will debunk it, the perfect crime, hide the truth in clear view, and make it sounds silly :D
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 11:09 am

yabeweb wrote:
planecane wrote:
kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?

The old saying is there are no stupid questions. Absolutely, the FAA is working with Boeing to find an issue that will cause a delay of weeks or months as a PR stunt.

Yeah.. who would suspect that right??

Also, make it sounds stupid and impossible, and people will debunk it, the perfect crime, hide the truth in clear view, and make it sounds silly :D


Except nobody released the info until CNN turned it up through sources. If PR was the goal it could have been accomplished by saying that the FAA determined more scenarios needed to be tested beyond what Boeing was doing and that it would take approximately a week.

Mitigating this risk is going to cause a delay of several weeks AT MINIMUM costing Boeing millons of dollars more in compensation. Nobody is doing that as a PR stunt.
 
yabeweb
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 11:20 am

planecane wrote:
Nobody is doing that as a PR stunt.

Aaaaaaand mission accomplished (aka it's "impossible" hence it's false)

Pulling your leg here, but still it is a possible (unlikely) scenario, after Both Boeing and FAA lost completely credibility.

You make it sounds like this "extra" makes grounding longer, what if instead it is buying Boeing time to finish up what they started, so Boeing wins time, and FAA wins PR, it's a Win Win situation (again not that I think it's true, but possible).

This way Boeing benefit also from, we are not making the grounding longer because Being cannot fix the damn thing in time, but because by more testing we both find out we needed some extra care... you know ... "Safety first™".
 
Interested
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 11:28 am

kayik wrote:
Would you be surprised if this was a PR effort staging how effective FAA is and not rubber stamping at all?



Based on the number of negative media articles this news has created and the fact each one makes Boeing appear more incompetent then if it's a PR stunt and Boeing were party to it - then it's completely backfired
 
smartplane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Thu Jun 27, 2019 11:35 am

xmp125a wrote:
JerseyFlyer wrote:
Is a fair deduction from this latest news that the crashed aircraft may have been irrecoverable, whatever the pilots did, because the computer "hung". My layman's language, obviously.


Given that it is not a FBW plane, are we again at the same old MCAS story? Plane that IS FLYABLE getting crashed by electronics (which is not up to FBW redundancy standards, because it does not have to be, since there exist mechanical/hydraulical connections between the pilot and the flying surfaces?)

Yet another dimension to grandfathering. Not only hardware and training is compromised to avoid being 'different', and losing grandfathering, but software too.

Instead of completely integrating new and old code seamlessly, presumably the old code is untouched to preserve grandfathered status, and then the new code is added. Neither best practice, elegant or safe.

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