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flyingphil
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 8:08 pm

Noshow wrote:
So what is the reported "design issue" with Ryanair's 737-8-200 about? The exit door itself? Structure? High density passenger loading becoming too tail heavy?


Did it fail an evacuation test? The usually talkative MOL hasn’t added any details.
I imagine his patience with Boeing is running out.

At least he has the Lauda Air Airbus fleet he can add to..
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 8:33 pm

morrisond wrote:
JetBuddy wrote:
As mentioned earlier, "The FAA has taken further control over certification of individual 737 Max aircraft, saying it will not allow Boeing itself to issue the airworthiness certificates that permit specific aircraft to be flown."

FAA will now inspect and sign off on every single frame individually, and issue Airworthyness Certificates to each of them. And only after a general Airworthyness Directive is issued for the 737 MAX type.

I think this is a good move, and will increase the confidence of the flying public with regards to the 737 MAX. At least that's how I feel about it.

https://www.flightglobal.com/news/artic ... ce-462555/


Good idea. Maybe they should be signing off on each individual pilot as well or training organization.


Indeed.

But only those pilots who will fly the MAX.

The 787, 350, 320, 320neo pilot group worldwide, don't seem to be affected by this supposedly pilot and training organization issues. At least not to the same extent, in the sense of several orders of magnitudes difference . . .
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 9:30 pm

morrisond wrote:
rheinwaldner wrote:
Can you tell me, why global aviation safety should be the prevalent topic in this thread?


It's because you keep making it with some of your ridiculous statements that need to be refuted when you know that whatever version of the MAX flies again won't be the same as MAX with MCAS V1.0 and it won't crash X times more often than average.

Which of my statements made you believe this? I never said anything close to that.

morrisond wrote:
rheinwaldner wrote:
Don't you think, that getting from 1 to 2 should have enough meat on the bone to discuss in this thread and that getting from 2 to 3 is distracting and off topic? Just look at the leverage, these two discussions have!


Ok then let's discuss that - what pearls of wisdom would you like to offer?

I am interested in an ontopic discussion. See the diagram. The MAX needs to come from ~4500 fatalities per trillion RPK to a normal level of ~100 fatalities per trillion RPK. That's what this thread is about. 90% of what you posted (and you posted a lot in these MAX threads) does not fall into this category.

I think, the MAX will be "normal" safety wise once the mistakes of the initial MAX designs will be properly addressed...
Many things are difficult, all things are possible!
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 9:38 pm

PW100 wrote:
morrisond wrote:
JetBuddy wrote:
As mentioned earlier, "The FAA has taken further control over certification of individual 737 Max aircraft, saying it will not allow Boeing itself to issue the airworthiness certificates that permit specific aircraft to be flown."

FAA will now inspect and sign off on every single frame individually, and issue Airworthyness Certificates to each of them. And only after a general Airworthyness Directive is issued for the 737 MAX type.

I think this is a good move, and will increase the confidence of the flying public with regards to the 737 MAX. At least that's how I feel about it.

https://www.flightglobal.com/news/artic ... ce-462555/


Good idea. Maybe they should be signing off on each individual pilot as well or training organization.


Indeed.

But only those pilots who will fly the MAX.

The 787, 350, 320, 320neo pilot group worldwide, don't seem to be affected by this supposedly pilot and training organization issues. At least not to the same extent, in the sense of several orders of magnitudes difference . . .


So it's the MAX pilots now that are the problem vs the MAX design? Just kidding but you put your foot in your mouth on that one.

I would suggest that mandatory stall training like what is happening in the US right now would be a great idea for all pilots worldwide. If that had been recurring prior to 10 years ago that could have reduced Rheinwaldners 3-4 Gap to almost zero and the MAX tragedies would have stood out even more.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 9:39 pm

rheinwaldner wrote:
morrisond wrote:
rheinwaldner wrote:
Can you tell me, why global aviation safety should be the prevalent topic in this thread?


It's because you keep making it with some of your ridiculous statements that need to be refuted when you know that whatever version of the MAX flies again won't be the same as MAX with MCAS V1.0 and it won't crash X times more often than average.

Which of my statements made you believe this? I never said anything close to that.

morrisond wrote:
rheinwaldner wrote:
Don't you think, that getting from 1 to 2 should have enough meat on the bone to discuss in this thread and that getting from 2 to 3 is distracting and off topic? Just look at the leverage, these two discussions have!


Ok then let's discuss that - what pearls of wisdom would you like to offer?

I am interested in an ontopic discussion. See the diagram. The MAX needs to come from ~4500 fatalities per trillion RPK to a normal level of ~100 fatalities per trillion RPK. That's what this thread is about. 90% of what you posted (and you posted a lot in these MAX threads) does not fall into this category.

I think, the MAX will be "normal" safety wise once the mistakes of the initial MAX designs will be properly addressed...


And normal can be almost zero with some pretty simple training - see above.
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Nov 27, 2019 10:40 pm

morrisond wrote:
rheinwaldner wrote:
morrisond wrote:

It's because you keep making it with some of your ridiculous statements that need to be refuted when you know that whatever version of the MAX flies again won't be the same as MAX with MCAS V1.0 and it won't crash X times more often than average.

Which of my statements made you believe this? I never said anything close to that.

morrisond wrote:

Ok then let's discuss that - what pearls of wisdom would you like to offer?

I am interested in an ontopic discussion. See the diagram. The MAX needs to come from ~4500 fatalities per trillion RPK to a normal level of ~100 fatalities per trillion RPK. That's what this thread is about. 90% of what you posted (and you posted a lot in these MAX threads) does not fall into this category.

I think, the MAX will be "normal" safety wise once the mistakes of the initial MAX designs will be properly addressed...


And normal can be almost zero with some pretty simple training - see above.

Pretty unlikely. There would probably be few more problems to work out. MAX - like WIndows - should be finally OK after 2 more service packs, 2025 or so,
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 12:48 am

art wrote:
Actually I, too, think it is a good idea in terms of winning back public confidence in the MAX. I guess a lot of average Joe's have lost faith in Boeing. I think the more involvement the FAA is seen to have, the more confidence in the airplane will return.

So the FAA who botched the initial certification of the MAX will now certify every individual a/c and that will raise confidence in the travelling public that that the MAX is now safe to fly.
I guess I am the only one who is of the opinion that the FAA is doing this to deflect all blame on the issue to Boeing and in line with this thread parameters it is 100% Boeing fault, anything else if off topic.

I guess I will have to wait to see what the politicians eventually do to rehabilitate the FAA and restore public confidence in their ability to oversee and regulate commercial aviation in the USA.
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 5:18 am

morrisond wrote:
rheinwaldner wrote:
morrisond wrote:

It's because you keep making it with some of your ridiculous statements that need to be refuted when you know that whatever version of the MAX flies again won't be the same as MAX with MCAS V1.0 and it won't crash X times more often than average.

Which of my statements made you believe this? I never said anything close to that.

morrisond wrote:

Ok then let's discuss that - what pearls of wisdom would you like to offer?

I am interested in an ontopic discussion. See the diagram. The MAX needs to come from ~4500 fatalities per trillion RPK to a normal level of ~100 fatalities per trillion RPK. That's what this thread is about. 90% of what you posted (and you posted a lot in these MAX threads) does not fall into this category.

I think, the MAX will be "normal" safety wise once the mistakes of the initial MAX designs will be properly addressed...


And normal can be almost zero with some pretty simple training - see above.

It is almost zero. See the diagram. And do better in staying focused on the 45 times more rewarding issue. Which is the MAX.
Many things are difficult, all things are possible!
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 5:26 am

par13del wrote:
art wrote:
Actually I, too, think it is a good idea in terms of winning back public confidence in the MAX. I guess a lot of average Joe's have lost faith in Boeing. I think the more involvement the FAA is seen to have, the more confidence in the airplane will return.

So the FAA who botched the initial certification of the MAX will now certify every individual a/c and that will raise confidence in the travelling public that that the MAX is now safe to fly.
I guess I am the only one who is of the opinion that the FAA is doing this to deflect all blame on the issue to Boeing and in line with this thread parameters it is 100% Boeing fault, anything else if off topic.

I guess I will have to wait to see what the politicians eventually do to rehabilitate the FAA and restore public confidence in their ability to oversee and regulate commercial aviation in the USA.

Worst thing FAA could do. Don't do the job of the vendor. Let Boeing certify each max. Just do random sampling after certifying the changes required.
After the next incident, FAA would be left justifying its actions along with Boeing. Make it the complete responsibility of Boeing.
 
B777LRF
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:02 am

maint123 wrote:
Make it the complete responsibility of Boeing.


Allow me to let you in on a little secret of aviation: You may outsource the work, but you can never outsource the responsibility.

Thus, when Boeing have issued certificates it has done so under delegation from the FAA, but with the FAA retaining full responsibility. What the FAA have done is withdrawing the delegation, but the responsibility has always been theirs. What this tells us is that the FAA have lost trust in Boeing, with all the possible repercussions that may bring.
Signature. You just read one.
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:28 am

B777LRF wrote:
maint123 wrote:
Make it the complete responsibility of Boeing.


Allow me to let you in on a little secret of aviation: You may outsource the work, but you can never outsource the responsibility.

Thus, when Boeing have issued certificates it has done so under delegation from the FAA, but with the FAA retaining full responsibility. What the FAA have done is withdrawing the delegation, but the responsibility has always been theirs. What this tells us is that the FAA have lost trust in Boeing, with all the possible repercussions that may bring.

I think you are quite incorrect. Nowhere does the certifying body check each and every item a company produces.
Self certification incase of Boeing meant that Boeing was certifying the modifications in the max, which was the prime responsibility of FAA normally. But whether each plane produced by Boeing meets those changes is Boeing's responsibility. Same for every other manufacturer.
FAA okays the changes and Boeing adheres to the changes. Not FAAs job to check all 700 max produced. Its a bad precedent
 
olle
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:37 am

kalvado wrote:
morrisond wrote:
rheinwaldner wrote:
Which of my statements made you believe this? I never said anything close to that.


I am interested in an ontopic discussion. See the diagram. The MAX needs to come from ~4500 fatalities per trillion RPK to a normal level of ~100 fatalities per trillion RPK. That's what this thread is about. 90% of what you posted (and you posted a lot in these MAX threads) does not fall into this category.

I think, the MAX will be "normal" safety wise once the mistakes of the initial MAX designs will be properly addressed...


And normal can be almost zero with some pretty simple training - see above.

Pretty unlikely. There would probably be few more problems to work out. MAX - like WIndows - should be finally OK after 2 more service packs, 2025 or so,


In 2025 Windows seems to have been replaced by Unix / Linux versions, special Android and IOS ;-)

If you are worse then the competition long enough you are beeing replaced.

After 2015 I consider that Unix / Linux - Windows have got a market share 90% - 10%.

Only most people do not realize this. And even good sales people at microsoft cannot change it.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:21 am

maint123 wrote:
B777LRF wrote:
maint123 wrote:
Make it the complete responsibility of Boeing.


Allow me to let you in on a little secret of aviation: You may outsource the work, but you can never outsource the responsibility.

Thus, when Boeing have issued certificates it has done so under delegation from the FAA, but with the FAA retaining full responsibility. What the FAA have done is withdrawing the delegation, but the responsibility has always been theirs. What this tells us is that the FAA have lost trust in Boeing, with all the possible repercussions that may bring.

I think you are quite incorrect. Nowhere does the certifying body check each and every item a company produces.
Self certification incase of Boeing meant that Boeing was certifying the modifications in the max, which was the prime responsibility of FAA normally. But whether each plane produced by Boeing meets those changes is Boeing's responsibility. Same for every other manufacturer.
FAA okays the changes and Boeing adheres to the changes. Not FAAs job to check all 700 max produced. Its a bad precedent

I'm afraid the description given is quite correct. Suggest you go read the regulations relating to Certificate of Airworthiness and delegation. This is not compliance certification by some backstreet widget manufacturer. This is a novel and complex situation, potentially with novel personnel, procedures and location. Delegation should not be made unless and until it has been demonstrated that these can be relied upon. Remember, part of the reason we are in this situation is the first place is Boeing persuaded FAA that the use of MCAS on MAX was not novel and therefore could be delegated to Boeing for oversight without due consideration.

FAA is doing what is supposed o do this time.

Ray
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:38 am

PixelFlight wrote:
rheinwaldner wrote:
It should be clear to anybody, that this thread is not a nice place for Boeing fans. Thats the nature of the topic. Probably similar like A380 threads for the Airbus camp.

I made another illustration, that shows the ontopic- and the offtopic aspect:
Image

Don't you think, that getting from 1 to 2 should have enough meat on the bone to discuss in this thread and that getting from 2 to 3 is distracting and off topic? Just look at the leverage, these two discussions have!

:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:50 am

par13del wrote:
art wrote:
Actually I, too, think it is a good idea in terms of winning back public confidence in the MAX. I guess a lot of average Joe's have lost faith in Boeing. I think the more involvement the FAA is seen to have, the more confidence in the airplane will return.

So the FAA who botched the initial certification of the MAX will now certify every individual a/c and that will raise confidence in the travelling public that that the MAX is now safe to fly.
I guess I am the only one who is of the opinion that the FAA is doing this to deflect all blame on the issue to Boeing and in line with this thread parameters it is 100% Boeing fault, anything else if off topic.

I guess I will have to wait to see what the politicians eventually do to rehabilitate the FAA and restore public confidence in their ability to oversee and regulate commercial aviation in the USA.


The FAA already certifies every single aircraft, individually, they each have their own airworthiness certificate. Just like the FAA already certifies every US registered ATP flying. What the FAA is likely proposing to do is to individually conform each aircraft on return to service. This is likely because each of the airframes that has been stored during grounding is considered in an 'unconformed' state. They were all built at a time when the Type Certificate (TC) was suspended and as such flown as experimental aircraft. This means they won't be on Boeing's Production Certificate (PC). Individual conformance to type is standard for all pre-TC issuance aircraft, and in some cases a significant number of aircraft built after TC issuance. You saw this with the A380, due to production issues EASA conformed, to type a fairly large number of airframes prior to the type being placed on Airbus's PC.

What is different is that the FAA is publicly announcing that they will do something they would already have likely done. This is probably because they are trying to clean up their own image.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:55 am

XRAYretired wrote:
maint123 wrote:
B777LRF wrote:

Allow me to let you in on a little secret of aviation: You may outsource the work, but you can never outsource the responsibility.

Thus, when Boeing have issued certificates it has done so under delegation from the FAA, but with the FAA retaining full responsibility. What the FAA have done is withdrawing the delegation, but the responsibility has always been theirs. What this tells us is that the FAA have lost trust in Boeing, with all the possible repercussions that may bring.

I think you are quite incorrect. Nowhere does the certifying body check each and every item a company produces.
Self certification incase of Boeing meant that Boeing was certifying the modifications in the max, which was the prime responsibility of FAA normally. But whether each plane produced by Boeing meets those changes is Boeing's responsibility. Same for every other manufacturer.
FAA okays the changes and Boeing adheres to the changes. Not FAAs job to check all 700 max produced. Its a bad precedent

I'm afraid the description given is quite correct. Suggest you go read the regulations relating to Certificate of Airworthiness and delegation. This is not compliance certification by some backstreet widget manufacturer. This is a novel and complex situation, potentially with novel personnel, procedures and location. Delegation should not be made unless and until it has been demonstrated that these can be relied upon. Remember, part of the reason we are in this situation is the first place is Boeing persuaded FAA that the use of MCAS on MAX was not novel and therefore could be delegated to Boeing for oversight without due consideration.

FAA is doing what is supposed o do this time.

Ray


You are correct, as explained in another response, the FAA and all NAAs have the right to individually conform to type any article built under a Type Certificate that they issue. In fact until the manufacture is given permission to place the type onto their Production Certificate (PC) they FAA legally has to conform each article individually. The fact is that all of these MAX aircraft were built without a TC and as such they have not been conformed. The FAA will view them all as experimental aircraft and will insist on a process to conform them separate from the PC process. Airframes built after the re-issuance of the TC will probably be built on the PC and as such not require individual conformance.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:59 am

B777LRF wrote:
maint123 wrote:
Make it the complete responsibility of Boeing.


Allow me to let you in on a little secret of aviation: You may outsource the work, but you can never outsource the responsibility.

Thus, when Boeing have issued certificates it has done so under delegation from the FAA, but with the FAA retaining full responsibility. What the FAA have done is withdrawing the delegation, but the responsibility has always been theirs. What this tells us is that the FAA have lost trust in Boeing, with all the possible repercussions that may bring.


I doubt that is the case. If the FAA had lost trust in Boeing's ability to build to type then they would have globally suspended Boeing's Production Certificate. What the FAA is doing here is saying they cannot know that the airframes conform to type, as there is not Type Certificate for the MAX currently. As such each aircraft must be produced on the TC itself as it will not be eligible to be produced on the PC. Types can only be added to the PC once the TC is approved and the FAA is satisfied that the production system has updated to the new type. Because the airframes are produced on the TC Boeing has to present them individually to the FAA for conformance.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 10:45 am

phollingsworth wrote:
PixelFlight wrote:
rheinwaldner wrote:
It should be clear to anybody, that this thread is not a nice place for Boeing fans. Thats the nature of the topic. Probably similar like A380 threads for the Airbus camp.

I made another illustration, that shows the ontopic- and the offtopic aspect:
Image

Don't you think, that getting from 1 to 2 should have enough meat on the bone to discuss in this thread and that getting from 2 to 3 is distracting and off topic? Just look at the leverage, these two discussions have!

:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

The graph show the actual factual measurement, that perfectly indicate why the 737-8/9 MAX is grounding, the exact subject of this thread, vs the global pilot training off topic subject that still account for far too much posts here from a very few that don't want to understand despite many contributors explanations since so many months. The absurdity is that those few will probably have nothing to exchange about there favorite subject aside of justifying to post off topic.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 11:05 am

FluidFlow wrote:
Does anyone here, that is familiar with the technical aspects of the 737, know if the structural wash out of the wing got changed when the new winglet on the MAX got planned/installed and how much influence the new winglet has on tip stall characteristics of the 737 compared to the older/no winglets.

The reason I ask is, that as the winglet alone might not be a problem, in combination with the new nacelle the stall characteristics might actually become really nasty. If MCAS really is needed only to provide enough feed back before the stall, then fine but what happens when we enter stall conditions. As the tip (in general) will stall first and then the rest of the wing, the combination of lift in front of the CoG by the nacelles and a tip stall and therefore loss of lift behind the CoG could result in a really strong pitch up moment.

If the horizontal stabilizer does not have enough authority in a situation like that, the 737 would be in a stall similar to a deep stall. Now this is of course pretty bad and hopefully just overstated but the aggressiveness of MCAS and the fact that we still have no actual clue how the 737 MAX behaves close to a stall without electronic helpers points to very bad flight characteristics that needed solutions to avoid them situations by all means.

This would also mean that a broken AoA probe would degrade the 737 into a really dangerous state.


I would expect that the new winglets don't have a significant effect on the approach to stall behaviour of the wing. Though, the aerodynamics here are potentially quite complex and emergent behaviour is always a possibility. The reason is Winglets reduce the amount of span wise flow. Further for the tailplane to loose that much authority would require some combination of two things.
  • Masking of the Horizontal by the wing – the classic deapstall problem
  • A significant shift in the neutral point so as to reduce elevator effectiveness catastrophically

The second only happens if the aircraft goes quite massively unstable. This is because elevator effectiveness is inversely proportional to the static margin, both positive and negative. If this were to happen we would see the aircraft go unstable as it approaches stall.

What is much more likely to be the case, and aligns very well with the extension of MCAS to level flight conditions, is that the aircraft's overall lift curve slope is basically flat at stall and then rises again quite early in the 'post-stall' regime. This is because in reality much of the wing isn't stalled due to nacelle wing interactions. This is a problem that emerges on all modern aircraft with underwing engines. We see it on 737NGs, A320s, A330s, etc. They can maintain 1g flight quite well in the post-stall regime, but cannot maintain level flight. For aircraft like the 777 and 787 this will be countered in the feel system in the FBW logic, for the Airbus FBW aircraft we just don't let you get close to this regime by having a hard AoA limit protection. The 737 is a weird beast. It still has truly manually drive, reversible controls (with hydraulic assist). For the NG the approach to stall is 'assisted' by the Speed Trim System (STS) which dials in significant nose down as the airspeed drops. Most likely Boeing realised that this schedule alone would have been insufficient given the changes to the MAX handling qualities, wings-level. As Peter Lemme points out one solution would be to revise the elevator feel system to artificially provide more nose-down effort. However, my guess is this was not the preferred solution for a number of reasons, especially relatively late in the development cycle. Instead you had a system, already in development, that could easily be extended, had a FMA that said it was at worst major if things went wrong. Of course the FMA was no-longer appropriate when you changed the behaviour (and may never have been appropriate due to improper discounting).

The consequence is that MCAS changed the behaviour of the STS failure mode that NG pilots are well trained on.
  • MACS removed the aft-column cutout – This is because it was originally designed for a wind-up turn, where the pilots would most likely be pulling back past the cutout point
  • MCAS changed the trim actuation failure behaviour – STS is based on a single sensor (airspeed) and if this were to read artificially low it induces a constant nose down trim application until it is stopped or reaches its limit. MCAS, however, is intermittent, so it runs-stops-runs-stops. This looks much less like a failure and more like it is doing something intended
  • MCAS added auto trim authority beyond what STS could bring – Higher rates, and allows the aircraft to go to the full nose down trim stop
  • MACS reactivates after 5 seconds – the beast keeps biting. Further, as the aircraft gets further and further out of trim and the yoke pressure increases the electronic counter-trim rate relative to the MCAS trim rate decreases. So you need much more than 5-seconds of nose up trim to counter 5-seconds of MCAS nose down trim.

If we move to the proposed MCAS 2.0 and the fail to inactive rate moves to better 1E-5 and the fail wrong rate moves to better than 1E-9 (these are the assumptions for a single vs common dual AoA failure), everything changes significantly. Instead you get
  • A condition where 1 in every 100,000 flight hours MCAS stops working. This isn't much of an issue in the Normal Flight Envelope, pilots just need to be aware it isn't there. In the roughly 1 in 100,000,000 flight hour condition where you are in the Operational Flight Envelope this would be more risky, but still manageable as it is very similar to no having STS protection
  • A condition where every 1 in 1,000,000,000 flight hours where you have MCAS firing when it shouldn't. This can lead to a catastrophic outcome, but that isn't guaranteed. However, this is considered acceptable by the aviation community

In reality single AoA failures on Boeing models occur about 1 in 10,000,000 flight hours, so the dual common failure is probably closer to 1E-11 instead of 1E-9. This is because if one AoA sensor fails the probability that the other will fail is slightly greater than 1E-5/1E-7.

Note: moving from a duplex to triplex AoA architecture only effects the first condition above, since it is only designed to preserve functionality on a single sensor failure. However, it also increases the likelihood that you have a single sensor failure and the likelihood that you have a dual common failure. So if the behaviour in condition 1 is acceptable an the only risk is condition 2 a triplex system is actually slightly less safe than a duplex system.
Last edited by phollingsworth on Thu Nov 28, 2019 11:18 am, edited 2 times in total.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 11:14 am

PixelFlight wrote:
phollingsworth wrote:
PixelFlight wrote:
:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

The graph show the actual factual measurement, that perfectly indicate why the 737-8/9 MAX is grounding, the exact subject of this thread, vs the global pilot training off topic subject that still account for far too much posts here from a very few that don't want to understand despite many contributors explanations since so many months. The absurdity is that those few will probably have nothing to exchange about there favorite subject aside of justifying to post off topic.


While this thread has a number or posts that fall in the area you and other think are off topic. A good chart to illustrate this would not use the numbers. The reason why is 4500 per trillion RPKs (nor is per RPK a particularly useful denominator) is not a correct prediction of future fatality rate of 737MAX with MCAS1.0. The fact is that you have to consider the aircraft as a system including hardware, software, and 'gooey-ware'. So discussions on training are absolutely correct as part of the overall discussion of 737MAX and its return to service. If I could create a training system that put the probability of any system failure leading to a catastrophic accident at 1E-100 flight hours then it would make a lot of the systems design for the aircraft a lot simpler, less costly, and overall more reliable. Obviously I cannot do this. However, there is no reason to not look at improving training for all 737 pilots based on the outcome of these accidents. This has the potential to make all flights safer.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 11:40 am

A duplex system less safe than a triplex how exactly?

If one sensor fails, the duplex does not actually know which one did and has to turn itself off. A triplex sensor is able to compare 3 datasets and if 2 match it is able to disregard (the most likely faulty) - the system can stay active.
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 11:58 am

phollingsworth wrote:
PixelFlight wrote:
rheinwaldner wrote:
It should be clear to anybody, that this thread is not a nice place for Boeing fans. Thats the nature of the topic. Probably similar like A380 threads for the Airbus camp.

I made another illustration, that shows the ontopic- and the offtopic aspect:
Image

Don't you think, that getting from 1 to 2 should have enough meat on the bone to discuss in this thread and that getting from 2 to 3 is distracting and off topic? Just look at the leverage, these two discussions have!

:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.
Many things are difficult, all things are possible!
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 12:16 pm

phollingsworth wrote:
PixelFlight wrote:
phollingsworth wrote:

A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

The graph show the actual factual measurement, that perfectly indicate why the 737-8/9 MAX is grounding, the exact subject of this thread, vs the global pilot training off topic subject that still account for far too much posts here from a very few that don't want to understand despite many contributors explanations since so many months. The absurdity is that those few will probably have nothing to exchange about there favorite subject aside of justifying to post off topic.


While this thread has a number or posts that fall in the area you and other think are off topic. A good chart to illustrate this would not use the numbers. The reason why is 4500 per trillion RPKs (nor is per RPK a particularly useful denominator) is not a correct prediction of future fatality rate of 737MAX with MCAS1.0. The fact is that you have to consider the aircraft as a system including hardware, software, and 'gooey-ware'. So discussions on training are absolutely correct as part of the overall discussion of 737MAX and its return to service. If I could create a training system that put the probability of any system failure leading to a catastrophic accident at 1E-100 flight hours then it would make a lot of the systems design for the aircraft a lot simpler, less costly, and overall more reliable. Obviously I cannot do this. However, there is no reason to not look at improving training for all 737 pilots based on the outcome of these accidents. This has the potential to make all flights safer.

Thing is, you can redesign 737 into NG, MAX, MCAS 2.0, 3.0 etc. But you would still have a pilot Mk.1, with brain designed for jumping from tree to tree and stealing pray from lions.
Limitations of that design are somewhat understood, and it is easily the least reliable part of most modern machines. Complex, capable - but not reliable, especially in high stress quick responce scenarios.
One of limitations of Mk1 is poor learning skills. We see a lot of people here who fail to appreciate Mk1 limitations and try to design with other assumptions. Results can be MAXed out.
Someday there will be Human Mk.2 and so on. That would change a lot of things. But there is no design toolset yet; and even if there were - it takes decades to ship out a properly trained human being, at least in Mk 1. So airplanes have to be designed to limitatons of Mk 1 for at least another 20-30 years, love it or hate it.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 1:47 pm

phollingsworth wrote:
PixelFlight wrote:
phollingsworth wrote:

A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

The graph show the actual factual measurement, that perfectly indicate why the 737-8/9 MAX is grounding, the exact subject of this thread, vs the global pilot training off topic subject that still account for far too much posts here from a very few that don't want to understand despite many contributors explanations since so many months. The absurdity is that those few will probably have nothing to exchange about there favorite subject aside of justifying to post off topic.


While this thread has a number or posts that fall in the area you and other think are off topic. A good chart to illustrate this would not use the numbers. The reason why is 4500 per trillion RPKs (nor is per RPK a particularly useful denominator) is not a correct prediction of future fatality rate of 737MAX with MCAS1.0. The fact is that you have to consider the aircraft as a system including hardware, software, and 'gooey-ware'. So discussions on training are absolutely correct as part of the overall discussion of 737MAX and its return to service. If I could create a training system that put the probability of any system failure leading to a catastrophic accident at 1E-100 flight hours then it would make a lot of the systems design for the aircraft a lot simpler, less costly, and overall more reliable. Obviously I cannot do this. However, there is no reason to not look at improving training for all 737 pilots based on the outcome of these accidents. This has the potential to make all flights safer.

The graph is not about prediction. This thread could be appropriate if 737-7/8/9 MAX specific training will be requires to return to service, but as today this is a speculation with opposite arguments. The thread is not appropriate to talk about global aviation training, a very important subject that should have a specific thread since even before the 737-8 MAX introduction, because this situation is not new at all and certainly need to be improved. Sadly the regulators have not recently taken spectacular actions about global training, despite many accidents where better training could have changed the outcome, so there little to exchange about, and this is not because anyone here really think that global aviation training is not important. This is simply the actual observable state of the civil aviation set by the regulators, manufacturers, and operators. We are on this specific thread to exchange on an other subject: the 737-8/9 MAX grounding. In that context of on/off topic, the graph is absolutely perfect.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 4:27 pm

rheinwaldner wrote:
phollingsworth wrote:
PixelFlight wrote:
:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


Ok I will bite. I did read the graph, it is inappropriate, ie contains extra extraneous information that detracts from your overall point. In no way am I disputing that the MAX has a horrible record or that it is safe-enough. The graph is a retrospective number and isn't useful for some of the things it is implied to be. The point still remains that if you could solve, totally, the 2 to 3 problem via pilot training, you would not need to solve the 1 to 2. As you rightly say you can't and it is necessary to solve problem 1 to 2.

The decision to return MAX to service needs to be based on the belief of future loss rates. This means that past loss rates, while part of the prior information, are not the same a predictions of future loss rates. Even if MAX had continued flying the predicted fatalities per 100 million RPK would not be 4550.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 4:39 pm

phollingsworth wrote:
rheinwaldner wrote:
phollingsworth wrote:

A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


Ok I will bite. I did read the graph, it is inappropriate, ie contains extra extraneous information that detracts from your overall point. In no way am I disputing that the MAX has a horrible record or that it is safe-enough. The graph is a retrospective number and isn't useful for some of the things it is implied to be. The point still remains that if you could solve, totally, the 2 to 3 problem via pilot training, you would not need to solve the 1 to 2. As you rightly say you can't and it is necessary to solve problem 1 to 2.

The decision to return MAX to service needs to be based on the belief of future loss rates. This means that past loss rates, while part of the prior information, are not the same a predictions of future loss rates. Even if MAX had continued flying the predicted fatalities per 100 million RPK would not be 4550.

Get down and dirty. It was not intended to be intellectual puzzle.

Ray
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 4:50 pm

seahawk wrote:
A duplex system less safe than a triplex how exactly?

If one sensor fails, the duplex does not actually know which one did and has to turn itself off. A triplex sensor is able to compare 3 datasets and if 2 match it is able to disregard (the most likely faulty) - the system can stay active.


A duplex system may or may not be less safe than a triplex system. This depends on the type of failure mode and its consequences. As you mentioned a triplex system can use "voting" to maintain service with a single channel failure. In a duplex system (properly implemented) this would lead to loss of service. In this situation the default safety of the triplex system is higher. I say default as it depends on the final outcome as to whether or not it is consequential. Let us consider a situation where a sensor fails at a rate of 1e-5 flight hours. In a duplex system you will have a sensor failure roughly 2E-5 per flight hour, a triplex 3E-5 per flight hour, so 1.5 times more often. Though not very often. Now let us also suppose that when the system goes down there is a 1E-3 chance of an catastrophic accident. For the duplex system this means the rate of accidents is 2E-8 per flight hour or one every 500,000,000 flight hours (not good). The triplex system will go down 6E-10 per flight hour (provided the likelihood of a 2nd sensor failing is not covariant with the 1st one failing) and the catastrophic accident rate from this would be 6E-13 per flight hour, ie once per every 1.67 trillion flight hours (very good). However, if the rate of the system going down leads to a catastrophic accident change of 1E-8, the duplex system would be one accident every 5 trillion flights hours and the triplex every 167 quadrillion flight hours. This may seem like a big different but the effect of this on a fleet of 3000 aircraft flying 3000 hours per year on the actual accident rate is basically 0.

Now imagine those same system, suffering two identical sensor failure and these leading to 1 in 10 chance of a catastrophic outcome. Same ratios for this type of failure. The duplex will suffer this dual failure 1E-10 per flight hour, the triplex system will suffer this failure 2E-10 per flight hour, ie twice as often. the resulting catastrophic accident rate is 1E-11 and 2E-11 per flight hour (every 100 billion or 50 billion flight hours) respectively. Now this not a propblem since even the less safe system is once every 5,500 years. However, if the likelihoods of a 2nd failure increase the difference in absolute safety will grow larger. If the failure rate of the second sensor were 1E-3 per flight hour, the duplex is 1E-8 and the triplex 2E-9. The overall catastrophic accident rate from the system that is duplex is 1E-9 and the triplex 2E-9 (not good).
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 4:57 pm

phollingsworth wrote:
The decision to return MAX to service needs to be based on the belief of future loss rates.

Clearly no. The aircraft return to service will be done by the regulators and, especially in this case, there will carefully review formally each relevant requirements and conformity tests to ensure that _NO_ "belief" interfere with the re-certification process. There want to be as rigorous as possible to regain credibility. Safety assessment is all about determining failure rate in a very formal en documented procedure to prove that the design is safe enough for commercial operation. There no space for "belief" or failure rate as observed with the 737-8/9 MAX.

phollingsworth wrote:
This means that past loss rates, while part of the prior information, are not the same a predictions of future loss rates. Even if MAX had continued flying the predicted fatalities per 100 million RPK would not be 4550.

The graph is not a prediction, how hard is that to understand ?
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 5:21 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:
Good idea. Maybe they should be signing off on each individual pilot as well or training organization.

Indeed. But only those pilots who will fly the MAX.

The 787, 350, 320, 320neo pilot group worldwide, don't seem to be affected by this supposedly pilot and training organization issues. At least not to the same extent, in the sense of several orders of magnitudes difference . . .

So it's the MAX pilots now that are the problem vs the MAX design? Just kidding but you put your foot in your mouth on that one.


No worries on my foot. Point of course is that I replied to your suggestion on the pilot performance. Hence the extension of that to the MAX pilots is just your own conclusion, written in a different way.

And to answer the question: No, I don't think it's solely the MAX pilots. Though the MAX pilot training system should have been better adopted for MCAS 1.0 (apart from all the MCAS 1.0 short comings).
I don't see this as a black and white thing, so I have no intention to pitch the pilots versus the design, Again, that was your suggestion . . .`

In the grand scheme of things (both Max accidents), pilot performance is just a small hole in the many layers of the overall Swiss cheese.

Zooming in on pilot performance layers of the cheese, we can further split that out in a layer "general piloting standards worldwide" and a layer "Type specific training".
Again, I think the issues with general piloting standards worldwide are a relatively small hole, paling in comparison to the giant hole produced by the lack of MCAS training.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 5:29 pm

phollingsworth wrote:
seahawk wrote:
A duplex system less safe than a triplex how exactly?

If one sensor fails, the duplex does not actually know which one did and has to turn itself off. A triplex sensor is able to compare 3 datasets and if 2 match it is able to disregard (the most likely faulty) - the system can stay active.


A duplex system may or may not be less safe than a triplex system. This depends on the type of failure mode and its consequences. As you mentioned a triplex system can use "voting" to maintain service with a single channel failure. In a duplex system (properly implemented) this would lead to loss of service. In this situation the default safety of the triplex system is higher. I say default as it depends on the final outcome as to whether or not it is consequential. Let us consider a situation where a sensor fails at a rate of 1e-5 flight hours. In a duplex system you will have a sensor failure roughly 2E-5 per flight hour, a triplex 3E-5 per flight hour, so 1.5 times more often. Though not very often. Now let us also suppose that when the system goes down there is a 1E-3 chance of an catastrophic accident. For the duplex system this means the rate of accidents is 2E-8 per flight hour or one every 500,000,000 flight hours (not good). The triplex system will go down 6E-10 per flight hour (provided the likelihood of a 2nd sensor failing is not covariant with the 1st one failing) and the catastrophic accident rate from this would be 6E-13 per flight hour, ie once per every 1.67 trillion flight hours (very good). However, if the rate of the system going down leads to a catastrophic accident change of 1E-8, the duplex system would be one accident every 5 trillion flights hours and the triplex every 167 quadrillion flight hours. This may seem like a big different but the effect of this on a fleet of 3000 aircraft flying 3000 hours per year on the actual accident rate is basically 0.

Now imagine those same system, suffering two identical sensor failure and these leading to 1 in 10 chance of a catastrophic outcome. Same ratios for this type of failure. The duplex will suffer this dual failure 1E-10 per flight hour, the triplex system will suffer this failure 2E-10 per flight hour, ie twice as often. the resulting catastrophic accident rate is 1E-11 and 2E-11 per flight hour (every 100 billion or 50 billion flight hours) respectively. Now this not a propblem since even the less safe system is once every 5,500 years. However, if the likelihoods of a 2nd failure increase the difference in absolute safety will grow larger. If the failure rate of the second sensor were 1E-3 per flight hour, the duplex is 1E-8 and the triplex 2E-9. The overall catastrophic accident rate from the system that is duplex is 1E-9 and the triplex 2E-9 (not good).

Would prefer to read actual probabilities from a real design in operation.

Anyway, the systemic failure of sensors of the same type is a major problem, especially when inducted by the external environment that could potentially affect all the sensors at the same time. Aircraft must evolve to do better check the inputs. The 787 is know to have a synthetic airspeed that can't fail the same way as the real sensor. I hope this kind of synthetic sensors will be mandatory someday. I think it was the EASA that talked about the idea of a synthetic AoA sensor for the 737-8/9 MAX. But the obsolete 737-8/9 MAX data system could be a real problem to implement that idea.
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 5:51 pm

phollingsworth wrote:
seahawk wrote:
A duplex system less safe than a triplex how exactly?

If one sensor fails, the duplex does not actually know which one did and has to turn itself off. A triplex sensor is able to compare 3 datasets and if 2 match it is able to disregard (the most likely faulty) - the system can stay active.


A duplex system may or may not be less safe than a triplex system. This depends on the type of failure mode and its consequences. As you mentioned a triplex system can use "voting" to maintain service with a single channel failure. In a duplex system (properly implemented) this would lead to loss of service. In this situation the default safety of the triplex system is higher. I say default as it depends on the final outcome as to whether or not it is consequential. Let us consider a situation where a sensor fails at a rate of 1e-5 flight hours. In a duplex system you will have a sensor failure roughly 2E-5 per flight hour, a triplex 3E-5 per flight hour, so 1.5 times more often. Though not very often. Now let us also suppose that when the system goes down there is a 1E-3 chance of an catastrophic accident. For the duplex system this means the rate of accidents is 2E-8 per flight hour or one every 500,000,000 flight hours (not good). The triplex system will go down 6E-10 per flight hour (provided the likelihood of a 2nd sensor failing is not covariant with the 1st one failing) and the catastrophic accident rate from this would be 6E-13 per flight hour, ie once per every 1.67 trillion flight hours (very good). However, if the rate of the system going down leads to a catastrophic accident change of 1E-8, the duplex system would be one accident every 5 trillion flights hours and the triplex every 167 quadrillion flight hours. This may seem like a big different but the effect of this on a fleet of 3000 aircraft flying 3000 hours per year on the actual accident rate is basically 0.

Now imagine those same system, suffering two identical sensor failure and these leading to 1 in 10 chance of a catastrophic outcome. Same ratios for this type of failure. The duplex will suffer this dual failure 1E-10 per flight hour, the triplex system will suffer this failure 2E-10 per flight hour, ie twice as often. the resulting catastrophic accident rate is 1E-11 and 2E-11 per flight hour (every 100 billion or 50 billion flight hours) respectively. Now this not a propblem since even the less safe system is once every 5,500 years. However, if the likelihoods of a 2nd failure increase the difference in absolute safety will grow larger. If the failure rate of the second sensor were 1E-3 per flight hour, the duplex is 1E-8 and the triplex 2E-9. The overall catastrophic accident rate from the system that is duplex is 1E-9 and the triplex 2E-9 (not good).


But system sensor failure does not mean catastrophic result, as you would need an identical system failure. 2 faulty sensors would need to show the same wrong (but still within the possible range) data.
 
MSPNWA
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:03 pm

rheinwaldner wrote:
You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


No matter how you try to spin it, the graph is mathematically correct but theoretically flawed and essentially worthless in describing past risk, the exact causes of the gap, and obviously predicting future risk. It's assumes that the gap from 2 and 3 has absolutely nothing to do with the gap from 1 to 2, and that is not known. In fact, it's the opposite. The evidence strongly shows that the 2-3 gap is a factor in creating the size of the 1-2 gap. How much? We can't say exactly where, but we can say with confidence that the actual "MAX gap" is somewhere in the middle of 1-2. When dealing with such low sample sizes, data is skewed. Your graph cannot rule out a simple statistical anomaly. The famous example of an anomaly was Concorde. It went from the safest to the most dangerous in one flight. Was it actually the safest? Was it actually the most dangerous? Neither is the best answer. It's a prime example of why safety is NOT simply a measure of data. Let's take the MAX. Let's say either the airline and pilots had different people in charge that do their job correctly prior to either crash. The MAX would have no crashes. A known incident or two that can be corrected, but no deaths. Now what does your graph show? The 2-3 gap actually shrinks! Oh, did the pilots and others (global aviation) get better? No! Attempting to claim that the 2-3 gap is "off-topic" is simply attempt to prevent discussion that does not align with a particular narrative. The 2-3 gap is very much on-topic, because it's a known factor in the 1-2 gap.

PW100 wrote:
No worries on my foot.


Teeth marks do heal.

Good to see you understand pilot performance is part of the problem.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:41 pm

MSPNWA wrote:
rheinwaldner wrote:
You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


No matter how you try to spin it, the graph is mathematically correct but theoretically flawed and essentially worthless in describing past risk, the exact causes of the gap, and obviously predicting future risk. It's assumes that the gap from 2 and 3 has absolutely nothing to do with the gap from 1 to 2, and that is not known. In fact, it's the opposite. The evidence strongly shows that the 2-3 gap is a factor in creating the size of the 1-2 gap. How much? We can't say exactly where, but we can say with confidence that the actual "MAX gap" is somewhere in the middle of 1-2. When dealing with such low sample sizes, data is skewed. Your graph cannot rule out a simple statistical anomaly. The famous example of an anomaly was Concorde. It went from the safest to the most dangerous in one flight. Was it actually the safest? Was it actually the most dangerous? Neither is the best answer. It's a prime example of why safety is NOT simply a measure of data. Let's take the MAX. Let's say either the airline and pilots had different people in charge that do their job correctly prior to either crash. The MAX would have no crashes. A known incident or two that can be corrected, but no deaths. Now what does your graph show? The 2-3 gap actually shrinks! Oh, did the pilots and others (global aviation) get better? No! Attempting to claim that the 2-3 gap is "off-topic" is simply attempt to prevent discussion that does not align with a particular narrative. The 2-3 gap is very much on-topic, because it's a known factor in the 1-2 gap.

PW100 wrote:
No worries on my foot.


Teeth marks do heal.

Good to see you understand pilot performance is part of the problem.

Lets say there is a thread for global training standards? Oh there is. Off you go then.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 6:42 pm

rheinwaldner wrote:
phollingsworth wrote:
PixelFlight wrote:
:checkmark: :thumbsup: Such perfect graph ! xkcd level :D https://xkcd.com/

I think that the experiment to merge the specifics accidents threads into the grounding thread is a failure. I would prefer 4 threads: JT610, ET302, Grounding, Training. As for the fans, this more depend on the ability to collaborate by exchanging knowledge than confronting emotional irrationality...


A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


You won't stop will you.

On the other hand if the ET training system had trained there Pilots properly on the MCAS procedure - the crash rate would be half. Or if Lionair had bothered training proper CRM like they were was supposed to after AirAsia 8501 as dictated by their regulator - Lionair might never have happened either. The Captain might have finally figured out that turning off the Electric Trim was a good idea if the First Officer had actually been able to trim properly and keep it in the air for more than a few seconds, just like the prior flight did.

Better training could have kept the MAX at normal safety rates.
 
smartplane
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 7:11 pm

PixelFlight wrote:
The 787 is know to have a synthetic airspeed that can't fail the same way as the real sensor. I hope this kind of synthetic sensors will be mandatory someday. I think it was the EASA that talked about the idea of a synthetic AoA sensor for the 737-8/9 MAX. But the obsolete 737-8/9 MAX data system could be a real problem to implement that idea.

Hopefully more advanced than fitted to a new car I previously owned, where to save money, instead of each cylinder being fitted with a temperature sensor, the OEM fitted one sensor, on one cylinder, and used coolant temperature and a formula to predict the temperature of each of the other three. Unfortunately, a cylinder which had a catastrophic failure was not the one with the sensor fitted.
 
mjoelnir
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 7:14 pm

morrisond wrote:
rheinwaldner wrote:
phollingsworth wrote:

A nice graph, too bad it is mathematically incorrect. It describes past observations, but cannot make any statement about future probabilities. That being said, even if you did it correctly, ie follow Bayes, the predicted catastrophic accident rate for the MAX with MCAS 1.0 would be too high.

You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


You won't stop will you.

On the other hand if the ET training system had trained there Pilots properly on the MCAS procedure - the crash rate would be half. Or if Lionair had bothered training proper CRM like they were was supposed to after AirAsia 8501 as dictated by their regulator - Lionair might never have happened either. The Captain might have finally figured out that turning off the Electric Trim was a good idea if the First Officer had actually been able to trim properly and keep it in the air for more than a few seconds, just like the prior flight did.

Better training could have kept the MAX at normal safety rates.


What proper MCAS procedure, the not existing one? At the time of the ET crash MCAS and its workings were still the big secret and Boeing had sabotaged any possibility to train for MCAS. If let the the 737MAX simulator, that ET had bought, being fixed that way, that it would not show MCAS and it's failure modes.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 7:34 pm

mjoelnir wrote:
morrisond wrote:
rheinwaldner wrote:
You did not try too hard to understand the graph, didn't you?
If you look a bit closer and also read the text, then you see, that the chart just highlights, what topic gives by far the largest leverage to improve aviation safety. And, it is not pilot training.
The MAX up to now has such a horrible safety record, that fixing it is entirely Boeings job. Thats meant with bringing the MAX from point 1 (4550 fat.p.RPK) to point 2 (100 fat.p.RPK). Once the MAX works as robust and fault tolerant as e.g. the NG, the issue will be gone.
The rest of your post are just baseless claims. The provided fatalities statistics for the MAX is correct.


You won't stop will you.

On the other hand if the ET training system had trained there Pilots properly on the MCAS procedure - the crash rate would be half. Or if Lionair had bothered training proper CRM like they were was supposed to after AirAsia 8501 as dictated by their regulator - Lionair might never have happened either. The Captain might have finally figured out that turning off the Electric Trim was a good idea if the First Officer had actually been able to trim properly and keep it in the air for more than a few seconds, just like the prior flight did.

Better training could have kept the MAX at normal safety rates.


What proper MCAS procedure, the not existing one? At the time of the ET crash MCAS and its workings were still the big secret and Boeing had sabotaged any possibility to train for MCAS. If let the the 737MAX simulator, that ET had bought, being fixed that way, that it would not show MCAS and it's failure modes.

It was no big secret.

It was in the maintenance manuals before Lionair, after Lionair Boeing put out various directives and clarifications. Those who paid attention or were educated by their airlines properly had everything they needed to safely operate the MAX. Having the issue happening to them (ET pilots) should not have been a surprise and they should have easily been able to handle it. A simulator was not needed.

And before People go off the deep end on "stop blaming the pilots" I'm blaming the training system and if it wasn't for Rheinwaldner insisting that Pilot performance or lack thereof did not contribute at all or is fine as is continuously this issue would die into the background.

If you can Honestly say you would get on or put your loved ones an ET or Lionair flight given what we know with no reservations whatsoever then I'll listen to why the pilots were not a factor at all.
 
smartplane
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 7:54 pm

morrisond wrote:
mjoelnir wrote:
morrisond wrote:

You won't stop will you.

On the other hand if the ET training system had trained there Pilots properly on the MCAS procedure - the crash rate would be half. Or if Lionair had bothered training proper CRM like they were was supposed to after AirAsia 8501 as dictated by their regulator - Lionair might never have happened either. The Captain might have finally figured out that turning off the Electric Trim was a good idea if the First Officer had actually been able to trim properly and keep it in the air for more than a few seconds, just like the prior flight did.

Better training could have kept the MAX at normal safety rates.


What proper MCAS procedure, the not existing one? At the time of the ET crash MCAS and its workings were still the big secret and Boeing had sabotaged any possibility to train for MCAS. If let the the 737MAX simulator, that ET had bought, being fixed that way, that it would not show MCAS and it's failure modes.

It was no big secret.

It was in the maintenance manuals before Lionair, after Lionair Boeing put out various directives and clarifications. Those who paid attention or were educated by their airlines properly had everything they needed to safely operate the MAX. Having the issue happening to them (ET pilots) should not have been a surprise and they should have easily been able to handle it. A simulator was not needed.

Are flight crews expected to be conversant with maintenance manuals? Thankfully the learned minds at FAA, EASA, JATR and contracted advisors are open, multi-dimensional thinkers.
 
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scbriml
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:05 pm

morrisond wrote:
It was in the maintenance manuals before Lionair,


How many pilots read maintenance manuals? :shakehead:

Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.
Time flies like an arrow. Fruit flies like a banana!
There are 10 types of people in the World - those that understand binary and those that don't.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:06 pm

smartplane wrote:
morrisond wrote:
mjoelnir wrote:

What proper MCAS procedure, the not existing one? At the time of the ET crash MCAS and its workings were still the big secret and Boeing had sabotaged any possibility to train for MCAS. If let the the 737MAX simulator, that ET had bought, being fixed that way, that it would not show MCAS and it's failure modes.

It was no big secret.

It was in the maintenance manuals before Lionair, after Lionair Boeing put out various directives and clarifications. Those who paid attention or were educated by their airlines properly had everything they needed to safely operate the MAX. Having the issue happening to them (ET pilots) should not have been a surprise and they should have easily been able to handle it. A simulator was not needed.

Are flight crews expected to be conversant with maintenance manuals? Thankfully the learned minds at FAA, EASA, JATR and contracted advisors are open, multi-dimensional thinkers.


No but they are are expected to know by heart any new safety information that comes out on a plane they operate and ask any questions if they have them.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:07 pm

scbriml wrote:
morrisond wrote:
It was in the maintenance manuals before Lionair,


How many pilots read maintenance manuals? :shakehead:

Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.


We were talking about ET and the Bulletins and information that came out after Lionair - sorry I was not that clear.

The only information that was out before Lionair was what was in the maintenance manual.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:37 pm

morrisond wrote:
scbriml wrote:
morrisond wrote:
It was in the maintenance manuals before Lionair,


How many pilots read maintenance manuals? :shakehead:

Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.


We were talking about ET and the Bulletins and information that came out after Lionair - sorry I was not that clear.

The only information that was out before Lionair was what was in the maintenance manual.

And this was part of the problem according to many (USA) pilots:

"Dispute arises among U.S. pilots on Boeing 737 MAX system linked to Lion Air crash"
https://www.seattletimes.com/business/boeing-aerospace/dispute-arises-among-u-s-pilots-on-boeing-737-max-system-linked-to-lion-air-crash/

"Boeing 737 MAX Pilots Had No Idea What They Were Up Against"
https://www.engineering.com/Hardware/ArticleID/19269/Boeing-737-MAX-Pilots-Had-No-Idea-What-They-Were-Up-Against.aspx

"At meeting with Boeing staff, pilots fumed about being left in dark on 737 software"
https://www.latimes.com/business/la-fi-boeing-737-max-pilots-meeting-20190314-story.html

Could certainly find more examples...
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:50 pm

PixelFlight wrote:
morrisond wrote:
scbriml wrote:

How many pilots read maintenance manuals? :shakehead:

Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.


We were talking about ET and the Bulletins and information that came out after Lionair - sorry I was not that clear.

The only information that was out before Lionair was what was in the maintenance manual.

And this was part of the problem according to many (USA) pilots:

"Dispute arises among U.S. pilots on Boeing 737 MAX system linked to Lion Air crash"
https://www.seattletimes.com/business/boeing-aerospace/dispute-arises-among-u-s-pilots-on-boeing-737-max-system-linked-to-lion-air-crash/

"Boeing 737 MAX Pilots Had No Idea What They Were Up Against"
https://www.engineering.com/Hardware/ArticleID/19269/Boeing-737-MAX-Pilots-Had-No-Idea-What-They-Were-Up-Against.aspx

"At meeting with Boeing staff, pilots fumed about being left in dark on 737 software"
https://www.latimes.com/business/la-fi-boeing-737-max-pilots-meeting-20190314-story.html

Could certainly find more examples...


You just proved my point - yes the Lionair pilots had no idea - but by the time of ET they sure should have.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:57 pm

morrisond wrote:
scbriml wrote:
morrisond wrote:
It was in the maintenance manuals before Lionair,


How many pilots read maintenance manuals? :shakehead:

Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.


We were talking about ET and the Bulletins and information that came out after Lionair - sorry I was not that clear.

The only information that was out before Lionair was what was in the maintenance manual.

And the description in the manual was for MCAS V0.0. No use to man or beast.

Ray
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 8:59 pm

PixelFlight wrote:
phollingsworth wrote:
The decision to return MAX to service needs to be based on the belief of future loss rates.

Clearly no. The aircraft return to service will be done by the regulators and, especially in this case, there will carefully review formally each relevant requirements and conformity tests to ensure that _NO_ "belief" interfere with the re-certification process. There want to be as rigorous as possible to regain credibility. Safety assessment is all about determining failure rate in a very formal en documented procedure to prove that the design is safe enough for commercial operation. There no space for "belief" or failure rate as observed with the 737-8/9 MAX.

Well. if there is anything MCAS teach us about, that is the story of risk assessment being anything but exact science. There are lots of assumptions and guesstimates - and at least some of those are tested on small groups of people with specific background, if tested at all. As a result, there a lot of room for justifying that design is good - as opposed to actually making a good design and verifying it came out as expected.
If anything, Roger's commission report on Challenger crash, along with chapters of Feynmann book on background of that invetigation, is an excellent study material for this type of situation.
So yes, any RTS decision is ultimately based on faith in Boeing's engineering team doing mostly good job as it is impossible to verify each step.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:04 pm

morrisond wrote:
PixelFlight wrote:
morrisond wrote:

We were talking about ET and the Bulletins and information that came out after Lionair - sorry I was not that clear.

The only information that was out before Lionair was what was in the maintenance manual.

And this was part of the problem according to many (USA) pilots:

"Dispute arises among U.S. pilots on Boeing 737 MAX system linked to Lion Air crash"
https://www.seattletimes.com/business/boeing-aerospace/dispute-arises-among-u-s-pilots-on-boeing-737-max-system-linked-to-lion-air-crash/

"Boeing 737 MAX Pilots Had No Idea What They Were Up Against"
https://www.engineering.com/Hardware/ArticleID/19269/Boeing-737-MAX-Pilots-Had-No-Idea-What-They-Were-Up-Against.aspx

"At meeting with Boeing staff, pilots fumed about being left in dark on 737 software"
https://www.latimes.com/business/la-fi-boeing-737-max-pilots-meeting-20190314-story.html

Could certainly find more examples...


You just proved my point - yes the Lionair pilots had no idea - but by the time of ET they sure should have.

Pilots were overwhelmed.
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:10 pm

I paste the picture once more, so our imagination is not stressed too much while discussing point 1,2,3:
Image

phollingsworth wrote:
In no way am I disputing that the MAX has a horrible record or that it is safe-enough. The graph is a retrospective number and isn't useful for some of the things it is implied to be.

It does not imply anything about the future. It just shows why this thread should focus on the MAX (because fixing the mistakes of the MAX has by far the largest leverage) and not on pilot training (because the effect of pilot training is just ground noise compared to the safety improvement that will come from the MAX fix).

phollingsworth wrote:
The point still remains that if you could solve, totally, the 2 to 3 problem via pilot training, you would not need to solve the 1 to 2.

2 to 3 for most peope is solved. Look where the curve was a decade or two ago.

Also, don't forget, 100% safety is utopic as the curve is asymptotic!!

This means, that 0 fatalities will only be reached if year → ∞. The same applies to the associated cost. E.g. reducing the death toll per RPK by 100 in 1970 did cost the airlines a fraction of the cost, that did cost the same improvement in 1980. And today, the cost to reduce that function by another 100 can be considered unbearable. In other words, nobody will pay the price, that the reduction of that curve by another 100 would cost.

phollingsworth wrote:
The decision to return MAX to service needs to be based on the belief of future loss rates.

Yes, I believe the MAX need to be at point 2 after the fix (in line with all the other aircraft out there).

phollingsworth wrote:
Even if MAX had continued flying the predicted fatalities per 100 million RPK would not be 4550.

What are you talking about? The 4550 are just the fatalities per MAX RPK to this date brought into the scale of the diagram. Hello? Fatalities per trillion RPKs is just a scale! I can express any danger in transportation in that diagram, I just need to apply the correct scale. I could present the danger of driving my bike in that diagram. So I repeat, the 4550 are the fatalities per MAX RPK brought into the scale of the diagram. Nothing else.

I expected, that people would understand this (and that it does not mean, that after one trillion MAX RPKs the 4550 will be dead).

The diagram had another purpose. It nicely shows how little effect there is to be gained from more training (2 -> 3) and how crucial fixing the MAX is (1 -> 2). The dimension of the former problem is tiny compared to the MAX problem. Look at the diagram! Training makes up for a tiny portion of the problem!

MSPNWA wrote:
No matter how you try to spin it, the graph is mathematically correct but theoretically flawed and essentially worthless in describing past risk, the exact causes of the gap, and obviously predicting future risk. It's assumes that the gap from 2 and 3 has absolutely nothing to do with the gap from 1 to 2, and that is not known. In fact, it's the opposite.

You make a lot of bold claims without substance. Let me explain:

MSPNWA wrote:
The evidence strongly shows that the 2-3 gap is a factor in creating the size of the 1-2 gap. How much? We can't say exactly where,...

I can. Go to the second page of this thread. There is a post in which I explain. Before I quote the post once more let me summarize:

1. It is known how frequently aircraft crash due to pilot error
2. And it is also known how frequently aircraft crash due to technical faults (-> much less often than 1.)
3. The sum of the failure rates of each components (here: pilots and the aircraft itself) is the global crash rate

If you take these 3 figures, take them as the global standard, then consider the crash rate as failure rate (for 1. -> crash causing failure rate of pilots, for 2 -> crash causing failure rate of aircraft, for 3. -> The sum of both = global failure rate = number of crashes per flight globally) and finally compare them with how the MAX fared, then you see, that the MAX has magnitudes of orders worse stats than the global standard.

And because we looked at the contributing failures rates separately, we can now isolate the MAX as the single factor, that was causing the misery. It does also pass the logic test: the equally bad trained pilots did not cause notable peaks in the statistics as long as they flew anything else than the MAX. The MAX is the single factor that changed. Anything else is at point 2 in the graph already.

More details about the calculation can be taken from this post (and before you lose your temper read the additivity section under this link https://en.wikipedia.org/wiki/Failure_rate)
rheinwaldner wrote:
Part III:
I can even put it mathematically with the failure rate addition formula:
Λ crash = Λ pilot + Λ aircraft (in the context where failure is defined as a crash causing mishap).

In aviation prior the MAX, this figure was ever improving. The average between 2012 and 2017 was 0.00000024 crashes per flight. "Λ pilot" being the majority (just guessing: maybe 0.00000021) and "Λ aircraft" being the rest (0.00000003). The statistics are from this link: https://www.reuters.com/article/us-airl ... SKCN1OW007

The same formula with the MAX however looks like this:

flights: 250k (educated guess, derived from my educated guess, that the MAX totally flew 516khrs)
crashes: 2
These values give:
Λ crash = 0.000008 (33 times worse than aviation prior the MAX!!!)

Modify the formula to get the failure rate contributed by the MAX:
Λ MAX = Λ crash - Λ pilot

Now lets put in the same Λ pilot as above (because, as I said a hundreds of time: MAX pilots were not trained less than NG pilots):
Λ MAX = 0.000008 - 0.00000021 = 0.00000779

And now, this is the bummer and the real scandal: "Λ MAX" is 260 times worse than "Λ aircraft" in a world sans MAX!!!!!

In plain words this means, that the MAX has a (crash causing) system failure rate 260 times higher than the (crash causing) technical system failure rate in aviation prior the MAX.

How anybody can entertain the pilot discussion in the light of these numbers is beyond me.




morrisond wrote:
You won't stop will you.

On the other hand if the ET training system had trained there Pilots properly on the MCAS procedure - the crash rate would be half. Or if Lionair had bothered training proper CRM like they were was supposed to after AirAsia 8501 as dictated by their regulator - Lionair might never have happened either. The Captain might have finally figured out that turning off the Electric Trim was a good idea if the First Officer had actually been able to trim properly and keep it in the air for more than a few seconds, just like the prior flight did.

Better training could have kept the MAX at normal safety rates.

Why do you demand the pilots to fix broken aircraft? As evidenced above, the MAX was broken on a level which was magnitudes of orders worse than typical (260 higher crash causing technical failure rate than the expected average from all other aircraft).
Last edited by rheinwaldner on Thu Nov 28, 2019 9:21 pm, edited 1 time in total.
Many things are difficult, all things are possible!
 
rheinwaldner
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:20 pm

morrisond wrote:
You just proved my point - yes the Lionair pilots had no idea - but by the time of ET they sure should have.

That's wrong. Boeings official memo is so thin, that they would have to rely on newspaper articles to get the crucial information that you mean. I have experienced personally how a MAX pilot made a fool of herself even after the ET crash because she resisted to accept news from the newspaper and strictly relied on Boeings information.
Many things are difficult, all things are possible!
 
art
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 9:56 pm

scbriml wrote:
Pilots were not told about or trained on MCAS because Boeing hid it from them in order to avoid the requirement for additional training.


Short, sharp, succinct - summarises how 346 avoidable deaths were not, by choice, avoided.

I echo the emergent refrain from some that Boeing should go back to engineering airplanes instead of engineering profits.
 
maint123
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Thu Nov 28, 2019 11:59 pm

In auto mode, mcas is off but is the AOA sensor still giving feedback to the controls.?

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