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XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Dec 09, 2019 6:27 pm

phollingsworth wrote:
DenverTed wrote:
sgrow787 wrote:

I read recently they are reinserting the column stab cutout in the Max update (and removing the MCAS column electric trim cutout). So maybe this is one of the mitigating factors to address the flip-bit (easier to say) issue. Because comparing FCC outputs in a fail-safe design seems more difficult to me. And we have an indication (by a TC employee) that removing MCAS altogether might be an option.


If the column stab cutout shuts off MCAS, then how would MCAS work? Unless the cutout is at a force beyond what is needed to pull into a stall with MCAS. Because, pulling into a stall with MCAS generating more column force through the final degrees (or deceleration) are the mandated tests.


I have no idea if the aft column cutout is coming back. It exists for STS which is also a stall identification augmentation. So in theory it should be possible to define an aft column cutout for 1g MCAS. My understanding is that it was removed to allow it to work in the wind-up turn condition. It could be that it comes back in 1g, though that would increase the complexity of the software logic.

Could well be Mr Marko's functionality description for 12.1.1 software:

'SW Column Cutout'

Ray
 
sgrow787
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Dec 09, 2019 8:02 pm

patrickjp93 wrote:
All bugs are flaws, whether it's in an embedded system or not. If someone specifies it's architecturally or structurally flawed, that's significant.


I have never heard a software defect in my 20 years in real-time embedded software design for aerospace referred to as flaws. They are always referred to as bugs or defects. And I have never heard of a design defect referred to as a design bug. On the contrary, in the non-safety commercial software world, the words “bug” and “bug-fix” is ubiquitous in the frequent software updating of our smartphones, tablets, and laptop computers.

So, while all bugs may be flaws, not all flaws are bugs, and my opinion on the Washington Post’s “flawed flight control feature” in referring to the problematic MCAS, is that media is finally taking a step closer to acknowledging the problematic design of MCAS in this saga. This is in contrast to how they’ve referred to the issue in the past - as some sort of bug with a bug-fix in a future software update.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
Saintor
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Dec 09, 2019 11:25 pm

scbriml wrote:
Saintor wrote:
The frame by itself is not a problem.


The World's aviation authorities (and Boeing for that matter) disagree with you.


Unsubstantiated allegations. You are confusing frames and systems. The frames are ok and will return just as designed.
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Dec 09, 2019 11:39 pm

Saintor wrote:
scbriml wrote:
Saintor wrote:
The frame by itself is not a problem.


The World's aviation authorities (and Boeing for that matter) disagree with you.


Unsubstantiated allegations. You are confusing frames and systems. The frames are ok and will return just as designed.


If there are major aerodynamical deficites in the 737MAX its a frame problem not a systems problem
 
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scbriml
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Mon Dec 09, 2019 11:44 pm

Saintor wrote:
scbriml wrote:
Saintor wrote:
The frame by itself is not a problem.


The World's aviation authorities (and Boeing for that matter) disagree with you.


Unsubstantiated allegations. You are confusing frames and systems. The frames are ok and will return just as designed.


Allegations? :rotfl:

Semantics. The frame without MCAS was uncertifiable. The two are inextricably linked and the MAX is grounded.
Time flies like an arrow. Fruit flies like a banana!
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MrBretz
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 3:27 am

Here’s a new story on MAX production problems. An employee said he informed executives and the board about shoddy, chaotic production issues with the MAX and his issues were dismissed. He wonders if the issues he raised, though not MCAS related, may have contributed to the 2 crashes.

https://www.nytimes.com/2019/12/09/busi ... lower.html
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 12:05 pm

scbriml wrote:
Saintor wrote:
scbriml wrote:

The World's aviation authorities (and Boeing for that matter) disagree with you.


Unsubstantiated allegations. You are confusing frames and systems. The frames are ok and will return just as designed.


Allegations? :rotfl:

Semantics. The frame without MCAS was uncertifiable. The two are inextricably linked and the MAX is grounded.


The 737 airframe, both NG and MAX are uncertifiable without augmentation. However, so are the 757, A330, A320, 787, A350 .... The fact that aerodynamically the stall identification behaviour of every modern airliner does not meet either the letter or intent of the regulations WRT stall identification isn't really a problem. Is MAX worse than the others? It definitely has issues that the NG does not, but that doesn't mean unaugmented it is anywhere near the worst airframe. The question is does the augmentation system provide an aircraft with a low enough estimate of overall failure to be certifiable. The belief of the regulators is that the augmented MAX using MCAS1.0 does not meet this. They all originally said they believed it did; however, new information changed that belief.

As you rightly imply/state. The aircraft has to be viewed as a whole, including Hardware, Software, and Human systems. It is only when looking at it as a whole can we evaluate if it is sufficiently safe.

Interesting Thought: The regulators essentially set a safety "floor". You would think that the manufacturers would see value in safety beyond that. However, one of the challenges with a "floor" is that it effectively devalues safety improvements beyond that area.
 
phollingsworth
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 12:15 pm

MrBretz wrote:
Here’s a new story on MAX production problems. An employee said he informed executives and the board about shoddy, chaotic production issues with the MAX and his issues were dismissed. He wonders if the issues he raised, though not MCAS related, may have contributed to the 2 crashes.

https://www.nytimes.com/2019/12/09/busi ... lower.html


There are a disturbing number of people raising issues about Boeing's overall culture. However, given what is in the article the issues that the wistleblower identifies don't seem likely to have any direct link to both crashes. The indirect link to the overall culture is an issue, but that will manifest itself in lots of ways.

Why do I say this:
[list=][*]If it we a production issue then the failure mode should show up in all aircraft subject to the issue. This would be both NGs and MAXs. The failure being AoA sensors. The NGs would not progress to catastrophic events
[*]The overall AoA failure rate is about the same as it has been for the last decades. If they are being abused we should be seeing an increase in the failure rate
[*]There isn't any evidence that due to issues in manufacturing the MAX didn't behave "as designed" when the Captain's AoA sensor failed the way it did. It is the design that is an issue in that the "as designed" isn't the "as intended". [/list]

Issues with Boeing's production would effect their ability to build aircraft to type. It may be that the MAXs were not built to type. However, both of these crashes look to be the type not performing as intended in these failure modes, and that performance being catastrophic.
 
9Patch
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 2:22 pm

Leeham has a post about last weeks Boeing briefing for industry analysts last week (but not the media).
https://leehamnews.com/2019/12/10/first ... last-week/
They link to David Learmount, the former aviation safety editor for Flight International magazine blog: Some key highlights:

Boeing CEO Dennis Muilenberg says the successful return to service of the company’s 737 Max series depends on international consensus among the many national aviation authorities (NAA) that will see the aircraft operating in their countries.

Not just the US FAA.


He emphasised the point: “If we do not coordinate this [return to service] we may see some disaggregation, and I don’t think that’s a future any of us wants to see.”

Muilenberg is confident the combined hardware and software changes Boeing has developed for the Max will satisfy the FAA and the multinational Joint Operations Evaluation Board (JOEB).


Boeing test pilot and VP Operations Craig Bomben, who flew the 737 Max first flight and has coordinated development activity on the type since the accidents, described the essential difference between the original MCAS and Boeing’s proposed replacement: “We’ve moved from a very simple system to an intelligent system.”


Bomben said the new “intelligent” system has two AoA sensors instead of one, and if their readings differ by 5.5deg or more, MCAS is not triggered at all.

But if it is correctly triggered, the system now “operates only once per AoA event”, according to Bomben, and when it does trigger stabiliser movement, it memorises how much displacement has taken place, so if it were triggered again it would take account of existing stabiliser displacement and will not apply more than a safe cumulative limit.

https://davidlearmount.com/2019/12/07/m ... -decision/
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 2:31 pm

Is the full presentation available elsewhere? I mean what needs to be hidden? Don't they share it with all aviation authorities and airlines globally anyway?
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 2:32 pm

9Patch wrote:
Leeham has a post about last weeks Boeing briefing for industry analysts last week (but not the media).
https://leehamnews.com/2019/12/10/first ... last-week/
They link to David Learmount, the former aviation safety editor for Flight International magazine blog: Some key highlights:

Boeing CEO Dennis Muilenberg says the successful return to service of the company’s 737 Max series depends on international consensus among the many national aviation authorities (NAA) that will see the aircraft operating in their countries.

Not just the US FAA.


He emphasised the point: “If we do not coordinate this [return to service] we may see some disaggregation, and I don’t think that’s a future any of us wants to see.”

Muilenberg is confident the combined hardware and software changes Boeing has developed for the Max will satisfy the FAA and the multinational Joint Operations Evaluation Board (JOEB).


Boeing test pilot and VP Operations Craig Bomben, who flew the 737 Max first flight and has coordinated development activity on the type since the accidents, described the essential difference between the original MCAS and Boeing’s proposed replacement: “We’ve moved from a very simple system to an intelligent system.”


Bomben said the new “intelligent” system has two AoA sensors instead of one, and if their readings differ by 5.5deg or more, MCAS is not triggered at all.

But if it is correctly triggered, the system now “operates only once per AoA event”, according to Bomben, and when it does trigger stabiliser movement, it memorises how much displacement has taken place, so if it were triggered again it would take account of existing stabiliser displacement and will not apply more than a safe cumulative limit.

https://davidlearmount.com/2019/12/07/m ... -decision/

Thanks for the information.

I maybe have missed that point before, but it's the first time I see Boeing talking about hardware change (even unspecified) for the RTS.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
9Patch
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 2:35 pm

Again, via Leeham, at last weeks media briefing were Greg Feith and John Goglia. Feith is a former crash investigator for the National Transportation Safety Board. Goglia was a member of the Board. Feith wrote this on his Facebook page:

John and I will dissect the operations portion of the NTSC report in upcoming podcasts and utilize the information we received from Boeing to properly analyze the “facts” that the NTSC presented, and also discuss numerous issues the NTSC and media have failed to discuss or develop further in support of a proper identification of causal and contributing factors. Also, I will say that I have questioned the numerous statements and analysis of the”pilot experts,” including one expert who testified on the Hill that when he flew the “MAX” simulator that he experienced numerous warning lights and aural warnings that made it apparent that both accident flight crews were “overwhelmed” and “confused.” I’m not sure what simulator and/or MCAS profiles he was flying where he experienced these overwhelming warnings, but the profiles me,John and several other pilots flew only experienced the relevant “warnings” and cockpit noise - 1) stickshaker, 2) trim wheel movement, and 3) aircraft over speed at the end of the profile. If you read the NTSC report, they describe the sounds (warnings) that were recorded on the CVR. And from the summary of the recorded CVR conversations, it is apparent that the crew was able to communicate with each other without difficulty because there were no extraordinary loud noises or multiple aural warnings!! John and I will discuss this and many more elements over the next several podcasts that will air toward the end of December and into January. I guarantee that the FACTS will tell a different story about the two accidents.

https://www.facebook.com/AirCrashDetect ... 4454225304
Last edited by 9Patch on Tue Dec 10, 2019 2:40 pm, edited 1 time in total.
 
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aerolimani
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 2:37 pm

PixelFlight wrote:
9Patch wrote:
Leeham has a post about last weeks Boeing briefing for industry analysts last week (but not the media).
https://leehamnews.com/2019/12/10/first ... last-week/
They link to David Learmount, the former aviation safety editor for Flight International magazine blog: Some key highlights:

Boeing CEO Dennis Muilenberg says the successful return to service of the company’s 737 Max series depends on international consensus among the many national aviation authorities (NAA) that will see the aircraft operating in their countries.

Not just the US FAA.


He emphasised the point: “If we do not coordinate this [return to service] we may see some disaggregation, and I don’t think that’s a future any of us wants to see.”

Muilenberg is confident the combined hardware and software changes Boeing has developed for the Max will satisfy the FAA and the multinational Joint Operations Evaluation Board (JOEB).


Boeing test pilot and VP Operations Craig Bomben, who flew the 737 Max first flight and has coordinated development activity on the type since the accidents, described the essential difference between the original MCAS and Boeing’s proposed replacement: “We’ve moved from a very simple system to an intelligent system.”


Bomben said the new “intelligent” system has two AoA sensors instead of one, and if their readings differ by 5.5deg or more, MCAS is not triggered at all.

But if it is correctly triggered, the system now “operates only once per AoA event”, according to Bomben, and when it does trigger stabiliser movement, it memorises how much displacement has taken place, so if it were triggered again it would take account of existing stabiliser displacement and will not apply more than a safe cumulative limit.

https://davidlearmount.com/2019/12/07/m ... -decision/

Thanks for the information.

I maybe have missed that point before, but it's the first time I see Boeing talking about hardware change (even unspecified) for the RTS.

I also thought that the action to restore trim to the original position, after a high AOA event has occurred and MCAS has activated, was also a part of the original MCAS design. Apparently not.
 
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767333ER
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 4:28 pm

patrickjp93 wrote:
Frankly if Boeing were allowed to grandfather the 737 while raising the landing gear (and thus fitting the engines more classically), we wouldn't even be discussing this now. Airlines wouldn't care all that much over getting some more luggage ramps and vehicles. The simulator differential training is much more expensive to amortize.

That wasn’t directly an issue of grandfathering. It was an issue of requiring overwing exit slides which Boeing was to cheap to want to implement. I do have to wonder though if the exit door slides would have had to be improved resulting in the need for a bigger door to fit a bigger slide. I argue the plane should have them anyway but that’s me.
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2 ears for spatial hearing, 2 eyes for depth perception, 2 ears for balance... How did Boeing think 1 sensor was good enough?!
 
patrickjp93
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 4:51 pm

sgrow787 wrote:
patrickjp93 wrote:
All bugs are flaws, whether it's in an embedded system or not. If someone specifies it's architecturally or structurally flawed, that's significant.


I have never heard a software defect in my 20 years in real-time embedded software design for aerospace referred to as flaws. They are always referred to as bugs or defects. And I have never heard of a design defect referred to as a design bug. On the contrary, in the non-safety commercial software world, the words “bug” and “bug-fix” is ubiquitous in the frequent software updating of our smartphones, tablets, and laptop computers.

So, while all bugs may be flaws, not all flaws are bugs, and my opinion on the Washington Post’s “flawed flight control feature” in referring to the problematic MCAS, is that media is finally taking a step closer to acknowledging the problematic design of MCAS in this saga. This is in contrast to how they’ve referred to the issue in the past - as some sort of bug with a bug-fix in a future software update.


Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Tue Dec 10, 2019 5:39 pm

patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
patrickjp93
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 12:30 am

PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


A good friend in NASA with friends in the FAA. The software has been cleared to use only one AoA, but the AoA disagreement light is being made mandatory.

Given both the Ethiopian and Lion Air sensors were mis-calibrated by the same maintenance firm, that shouldn't be a big shock. They're not quite so sensitive that you have one failing every 1000 flights, far from it.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:16 am

patrickjp93 wrote:
PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


A good friend in NASA with friends in the FAA. The software has been cleared to use only one AoA, but the AoA disagreement light is being made mandatory.

Given both the Ethiopian and Lion Air sensors were mis-calibrated by the same maintenance firm, that shouldn't be a big shock. They're not quite so sensitive that you have one failing every 1000 flights, far from it.

Unverifiable sources... If you have no better argumentation, I still view the official "two sensors" scenario as the most plausible actually.

While the JT610 final report strongly suggest that the JT610 left AoA sensor was mis-calibrated at Xtra Aerospace, there are no definitive evidence that exclude more unlikely scenario.
The ET302 left AoA sensor is believed to have been ripped off by a bird impact based on the ET302 FDR. The ET302 FDR left AoA trace did not have offset when the aircraft accelerated and up to ~6 seconds after "ground" to "air" gear WoW signal transition.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
patrickjp93
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 3:51 am

PixelFlight wrote:
patrickjp93 wrote:
PixelFlight wrote:
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


A good friend in NASA with friends in the FAA. The software has been cleared to use only one AoA, but the AoA disagreement light is being made mandatory.

Given both the Ethiopian and Lion Air sensors were mis-calibrated by the same maintenance firm, that shouldn't be a big shock. They're not quite so sensitive that you have one failing every 1000 flights, far from it.

Unverifiable sources... If you have no better argumentation, I still view the official "two sensors" scenario as the most plausible actually.

While the JT610 final report strongly suggest that the JT610 left AoA sensor was mis-calibrated at Xtra Aerospace, there are no definitive evidence that exclude more unlikely scenario.
The ET302 left AoA sensor is believed to have been ripped off by a bird impact based on the ET302 FDR. The ET302 FDR left AoA trace did not have offset when the aircraft accelerated and up to ~6 seconds after "ground" to "air" gear WoW signal transition.


And a lot of Leeham's sources are unverified. If I gave you the internal docs, likely watermarked as they are, I'd lose more than a few people their jobs. The MCAS software revisions cleared all FAA requirements in early November and do not require input from 2 sensors to activate stall prevention maneuvers. When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.

Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions. FDRs are easy to tamper with given their encryption is trivial to crack thanks to draconian regulations. And Xtra is the maintenance partner for both airlines, so there's that to consider.

Beyond this, ensuring the sensor disagree light is provided on all craft and that MCAS is disabled in the event of a disagreement or loss of sensor mitigates the safety issues inherent to implementation 1.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 4:29 am

PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


I think the algorithm will still only use one sensor. It will compare the two and disable MCAS if there is a disagree. So, while it will take both sensors into account it will only use one of them for the algorithm input.
 
SFOtoORD
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 4:40 am

planecane wrote:
PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


I think the algorithm will still only use one sensor. It will compare the two and disable MCAS if there is a disagree. So, while it will take both sensors into account it will only use one of them for the algorithm input.


So basically it uses two sensors. In the case they agree it could have used either one. In the case they disagree it uses neither.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 4:47 am

SFOtoORD wrote:
planecane wrote:
PixelFlight wrote:
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


I think the algorithm will still only use one sensor. It will compare the two and disable MCAS if there is a disagree. So, while it will take both sensors into account it will only use one of them for the algorithm input.


So basically it uses two sensors. In the case they agree it could have used either one. In the case they disagree it uses neither.


You could say that. To me, using two sensors implies some kind of intelligence that tries to determine an accurate AoA if both sensors are reading something different. MCAS 2.0 doesn't do that.
 
SFOtoORD
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 4:50 am

planecane wrote:
SFOtoORD wrote:
planecane wrote:

I think the algorithm will still only use one sensor. It will compare the two and disable MCAS if there is a disagree. So, while it will take both sensors into account it will only use one of them for the algorithm input.


So basically it uses two sensors. In the case they agree it could have used either one. In the case they disagree it uses neither.


You could say that. To me, using two sensors implies some kind of intelligence that tries to determine an accurate AoA if both sensors are reading something different. MCAS 2.0 doesn't do that.


How do you use two data points with one likely incorrect/invalid to come up with a single consistently accurate data point? Seems like putting control back in the pilots hands is likely better.
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 7:54 am

patrickjp93 wrote:
... When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.......


The problem is not that the EASA sends test pilots.
The problem is - so far as one hears - that Boeing does not want to allow a test flight with the augmentation switched off, because the 737MAX is already an approved aircraft and the grounding concerns only the MCAS functionality, but not the flight characteristics of the frame.
 
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PixelFlight
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:04 am

planecane wrote:
PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


I think the algorithm will still only use one sensor. It will compare the two and disable MCAS if there is a disagree. So, while it will take both sensors into account it will only use one of them for the algorithm input.

Ok, you are certainly right.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
Noshow
Posts: 1603
Joined: Wed Jun 15, 2016 3:20 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:09 am

So we have a debate between Boeing and EASA about what they are permitted to test?
 
bluecrew
Posts: 40
Joined: Sun Apr 20, 2014 3:13 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:14 am

patrickjp93 wrote:
PixelFlight wrote:
patrickjp93 wrote:

A good friend in NASA with friends in the FAA. The software has been cleared to use only one AoA, but the AoA disagreement light is being made mandatory.

Given both the Ethiopian and Lion Air sensors were mis-calibrated by the same maintenance firm, that shouldn't be a big shock. They're not quite so sensitive that you have one failing every 1000 flights, far from it.

Unverifiable sources... If you have no better argumentation, I still view the official "two sensors" scenario as the most plausible actually.

While the JT610 final report strongly suggest that the JT610 left AoA sensor was mis-calibrated at Xtra Aerospace, there are no definitive evidence that exclude more unlikely scenario.
The ET302 left AoA sensor is believed to have been ripped off by a bird impact based on the ET302 FDR. The ET302 FDR left AoA trace did not have offset when the aircraft accelerated and up to ~6 seconds after "ground" to "air" gear WoW signal transition.


And a lot of Leeham's sources are unverified. If I gave you the internal docs, likely watermarked as they are, I'd lose more than a few people their jobs. The MCAS software revisions cleared all FAA requirements in early November and do not require input from 2 sensors to activate stall prevention maneuvers. When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.

Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions. FDRs are easy to tamper with given their encryption is trivial to crack thanks to draconian regulations. And Xtra is the maintenance partner for both airlines, so there's that to consider.

Beyond this, ensuring the sensor disagree light is provided on all craft and that MCAS is disabled in the event of a disagreement or loss of sensor mitigates the safety issues inherent to implementation 1.

So, I don't necessarily disagree with you, but...
If someone "hacked" and modified data in an FDR, they, and whoever was linked in the direction of them, would be sent to prison when they are (inevitably) caught.
I find that incredibly unlikely.
 
Noshow
Posts: 1603
Joined: Wed Jun 15, 2016 3:20 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:16 am

Didn't at least the Ethiopians hand over their recorder to BEA in France for professional handling and readout?
 
uta999
Posts: 917
Joined: Mon Jun 14, 2010 11:10 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:18 am

asdf wrote:
patrickjp93 wrote:
... When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.......


The problem is not that the EASA sends test pilots.
The problem is - so far as one hears - that Boeing does not want to allow a test flight with the augmentation switched off, because the 737MAX is already an approved aircraft and the grounding concerns only the MCAS functionality, but not the flight characteristics of the frame.


So hang on a minute. The MAX cannot fly or even be tested without MCAS, but the Boeing ‘solution’ involves turning off MCAS if there is ever an AoA disagree.

Surely the self-certification and Grandfathering nature of the MAX should mean everything needs to be checked again. In effect, it needs another year of testing, before RTS. If that were done properly, then MCAS might not even be needed. Boeing should have aimed to remove MCAS last March. It doesn’t work.
Your computer just got better
 
Noshow
Posts: 1603
Joined: Wed Jun 15, 2016 3:20 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:24 am

So are we moving away from RTS now?
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:29 am

patrickjp93 wrote:
PixelFlight wrote:
patrickjp93 wrote:
Too bad the software fix has been cleared and will still only use one AoA sensor. The design itself isn't flawed. The implementation is.
Sources ?

Because everything I have read so far point to a software upgrade that will use two AoA sensors. https://www.boeing.com/commercial/737max/737-max-software-updates.page
I haven't read any report that support that the STS MCAS implementation was anything but compliant with the requirements. See the NTSB part into the JT610 final report E.1.1 page 253 (PDF page 255).
The STS MCAS requirements was bad because of a flawed safety assessment based on unrealistic and non verified assumptions. See the JATR review.


A good friend in NASA with friends in the FAA. The software has been cleared to use only one AoA, but the AoA disagreement light is being made mandatory.

Given both the Ethiopian and Lion Air sensors were mis-calibrated by the same maintenance firm, that shouldn't be a big shock. They're not quite so sensitive that you have one failing every 1000 flights, far from it.

Nonsense conspiracy theories.

It has been reported that the AOA from the two sensors is compared to be within 5.5 degrees and compared to the last 'average value of the two sensors from the previous calibration and the average is used in calculation.

ET302 sensor is original fit and did not exhibit a problem until in flight.
 
bluecrew
Posts: 40
Joined: Sun Apr 20, 2014 3:13 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:33 am

uta999 wrote:
asdf wrote:
patrickjp93 wrote:
... When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.......


The problem is not that the EASA sends test pilots.
The problem is - so far as one hears - that Boeing does not want to allow a test flight with the augmentation switched off, because the 737MAX is already an approved aircraft and the grounding concerns only the MCAS functionality, but not the flight characteristics of the frame.


So hang on a minute. The MAX cannot fly or even be tested without MCAS, but the Boeing ‘solution’ involves turning off MCAS if there is ever an AoA disagree.

Surely the self-certification and Grandfathering nature of the MAX should mean everything needs to be checked again. In effect, it needs another year of testing, before RTS. If that were done properly, then MCAS might not even be needed. Boeing should have aimed to remove MCAS last March. It doesn’t work.

If this is all correct, and not conjecture (not yours alone, but also what you're responding to), then what we could be headed to is an entirely new certification process: perhaps a new certification, perhaps a new type rating.
MCAS was the bandaid that made this a same type cert specifically marketed towards SWA.
Certification isn't fast... but with an airplane that has previously been certified it probably wouldn't be slow (not a year). But... I'm inherently uneasy with a system that does what MCAS does (not typed). It doesn't indicate that the system is activated, there's no visual or aural indication that the system is controlling the elevator. OK, sure, turn it off with an AoA DISAG, but whenever that thing is working, I'd really appreciate a heads up.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 8:43 am

asdf wrote:
patrickjp93 wrote:
... When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.......


The problem is not that the EASA sends test pilots.
The problem is - so far as one hears - that Boeing does not want to allow a test flight with the augmentation switched off, because the 737MAX is already an approved aircraft and the grounding concerns only the MCAS functionality, but not the flight characteristics of the frame.

Nonsense conspiracy theories.

The EASA flight tests will be conducted when the certification standard software configured aircraft is available. The will be after the FAA Certification Flight tests yet to be conducted.

Stop feeding the trolls.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 9:19 am

bluecrew wrote:
patrickjp93 wrote:
PixelFlight wrote:
Unverifiable sources... If you have no better argumentation, I still view the official "two sensors" scenario as the most plausible actually.

While the JT610 final report strongly suggest that the JT610 left AoA sensor was mis-calibrated at Xtra Aerospace, there are no definitive evidence that exclude more unlikely scenario.
The ET302 left AoA sensor is believed to have been ripped off by a bird impact based on the ET302 FDR. The ET302 FDR left AoA trace did not have offset when the aircraft accelerated and up to ~6 seconds after "ground" to "air" gear WoW signal transition.


And a lot of Leeham's sources are unverified. If I gave you the internal docs, likely watermarked as they are, I'd lose more than a few people their jobs. The MCAS software revisions cleared all FAA requirements in early November and do not require input from 2 sensors to activate stall prevention maneuvers. When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.

Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions. FDRs are easy to tamper with given their encryption is trivial to crack thanks to draconian regulations. And Xtra is the maintenance partner for both airlines, so there's that to consider.

Beyond this, ensuring the sensor disagree light is provided on all craft and that MCAS is disabled in the event of a disagreement or loss of sensor mitigates the safety issues inherent to implementation 1.

So, I don't necessarily disagree with you, but...
If someone "hacked" and modified data in an FDR, they, and whoever was linked in the direction of them, would be sent to prison when they are (inevitably) caught.
I find that incredibly unlikely.

NTSB/FAA were fully involved in the recovery of the FDR and CVR data at BEA and have confirmed that they have the access required and did so immediately after the recovery was completed.

Don't feed the ridiculous theories.
 
Noshow
Posts: 1603
Joined: Wed Jun 15, 2016 3:20 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 9:37 am

Maybe you could kindly add some facts instead of just fighting statements within this discussion? We are at this point of speculation because no hard facts are made available. It was promised to be different. The flying public will not just "forget" and come back. People will need to be convinced because airlines want to fill their fleets. Why can nobody speak about what is going on? We are supposed to be close to certification flights so a lot of stuff must be ready for distribution? Keeping quiet about everything will not restore trust.
 
dc855
Posts: 31
Joined: Sat Jul 16, 2016 12:41 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 10:19 am

Sources from inside FI are now saying that in their planning for next summer, Icelandair is now taking into account the possibility that they will not be able to fly the MAX. Originally they were expecting RTS in March.

Source in Icelandic
https://www.mbl.is/vidskipti/frettir/20 ... rsetningu/
 
kalvado
Posts: 2817
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 11:14 am

XRAYretired wrote:
bluecrew wrote:
patrickjp93 wrote:

And a lot of Leeham's sources are unverified. If I gave you the internal docs, likely watermarked as they are, I'd lose more than a few people their jobs. The MCAS software revisions cleared all FAA requirements in early November and do not require input from 2 sensors to activate stall prevention maneuvers. When the EASA stops being childish and sends over test pilots instead of stonewalling, the 737 MAX will be in the skies immediately two weeks following.

Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions. FDRs are easy to tamper with given their encryption is trivial to crack thanks to draconian regulations. And Xtra is the maintenance partner for both airlines, so there's that to consider.

Beyond this, ensuring the sensor disagree light is provided on all craft and that MCAS is disabled in the event of a disagreement or loss of sensor mitigates the safety issues inherent to implementation 1.

So, I don't necessarily disagree with you, but...
If someone "hacked" and modified data in an FDR, they, and whoever was linked in the direction of them, would be sent to prison when they are (inevitably) caught.
I find that incredibly unlikely.

NTSB/FAA were fully involved in the recovery of the FDR and CVR data at BEA and have confirmed that they have the access required and did so immediately after the recovery was completed.

Don't feed the ridiculous theories.

If I remember correctly, US representatives had observer status. They were not actively involved. Totally understandable given many posters' first thought is how the data could be altered.
 
phollingsworth
Posts: 759
Joined: Sat Mar 06, 2004 6:05 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 11:21 am

bluecrew wrote:
uta999 wrote:
asdf wrote:

The problem is not that the EASA sends test pilots.
The problem is - so far as one hears - that Boeing does not want to allow a test flight with the augmentation switched off, because the 737MAX is already an approved aircraft and the grounding concerns only the MCAS functionality, but not the flight characteristics of the frame.


So hang on a minute. The MAX cannot fly or even be tested without MCAS, but the Boeing ‘solution’ involves turning off MCAS if there is ever an AoA disagree.

Surely the self-certification and Grandfathering nature of the MAX should mean everything needs to be checked again. In effect, it needs another year of testing, before RTS. If that were done properly, then MCAS might not even be needed. Boeing should have aimed to remove MCAS last March. It doesn’t work.

If this is all correct, and not conjecture (not yours alone, but also what you're responding to), then what we could be headed to is an entirely new certification process: perhaps a new certification, perhaps a new type rating.
MCAS was the bandaid that made this a same type cert specifically marketed towards SWA.
Certification isn't fast... but with an airplane that has previously been certified it probably wouldn't be slow (not a year). But... I'm inherently uneasy with a system that does what MCAS does (not typed). It doesn't indicate that the system is activated, there's no visual or aural indication that the system is controlling the elevator. OK, sure, turn it off with an AoA DISAG, but whenever that thing is working, I'd really appreciate a heads up.


What exactly are you uneasy with in the concept of MCAS. Keep in mind that this underlying functionality, deliberately creating a mis-trim condition as you approach stall has been used on numerous existing aircraft. You have Speed Trim System (STS) on 737NGs and 757s, You have the Airbus trim system on A300s and A310s, a different MCAS implementation on the 767-2C. My guess is you will also find some version of it in all of the FBW logic on 777, 787, A320s, A330s, etc. The reason is that the stall identification problem is common on all modern swept-wing airframes, especially those with Supercritical aerofoils. The nice thing about trim systems is that they most definitely don't change the elevator position, this means that there is an inherent ability to counter the motion, at least initially, with the primary pilot interface, ie stick or yoke. Moving the elevator is akin to a stick pusher/nudger. Airbus envelope protection does use the elevator in addition to trim, and if it were to go wrong it would happen even faster.

The activation of STS/MCAS is clearly indicated via movement of the trim wheels so it should be obvious when it is running. Now, it is unacceptable that Boeing did not call out the change in behaviour that MCAS introduced to the existing STS system, or even identified that the system is now driven by either airspeed or AoA individually. It is also, at first glance, unacceptable that the system has a single point of failure false positive. However, STS has the same issue WRT airspeed sensors and has not been a significant issue in the nearly 25 years of operation. Obviously, that prior learning proved to be inappropriate.
 
planecane
Posts: 1568
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 11:33 am

SFOtoORD wrote:
planecane wrote:
SFOtoORD wrote:

So basically it uses two sensors. In the case they agree it could have used either one. In the case they disagree it uses neither.


You could say that. To me, using two sensors implies some kind of intelligence that tries to determine an accurate AoA if both sensors are reading something different. MCAS 2.0 doesn't do that.


How do you use two data points with one likely incorrect/invalid to come up with a single consistently accurate data point? Seems like putting control back in the pilots hands is likely better.


You don't. That's why it still only uses one sensor for the algorithm.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 11:34 am

kalvado wrote:
XRAYretired wrote:
bluecrew wrote:
So, I don't necessarily disagree with you, but...
If someone "hacked" and modified data in an FDR, they, and whoever was linked in the direction of them, would be sent to prison when they are (inevitably) caught.
I find that incredibly unlikely.

NTSB/FAA were fully involved in the recovery of the FDR and CVR data at BEA and have confirmed that they have the access required and did so immediately after the recovery was completed.

Don't feed the ridiculous theories.

If I remember correctly, US representatives had observer status. They were not actively involved. Totally understandable given many posters' first thought is how the data could be altered.

NTSB are participants and have confirmed they have the access they require.
 
kalvado
Posts: 2817
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 11:38 am

XRAYretired wrote:
kalvado wrote:
XRAYretired wrote:
NTSB/FAA were fully involved in the recovery of the FDR and CVR data at BEA and have confirmed that they have the access required and did so immediately after the recovery was completed.

Don't feed the ridiculous theories.

If I remember correctly, US representatives had observer status. They were not actively involved. Totally understandable given many posters' first thought is how the data could be altered.

NTSB are participants and have confirmed they have the access they require.

Fine difference is between having access to the data others obtained vs actually being in physical control, including ability to alter raw data before it is shared. Many posters complain US agencies didn't have the later.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 12:34 pm

kalvado wrote:
XRAYretired wrote:
kalvado wrote:
If I remember correctly, US representatives had observer status. They were not actively involved. Totally understandable given many posters' first thought is how the data could be altered.

NTSB are participants and have confirmed they have the access they require.

Fine difference is between having access to the data others obtained vs actually being in physical control, including ability to alter raw data before it is shared. Many posters complain US agencies didn't have the later.

If you and friends cant assimilate the information provided, no one can help you. Suggest find a conspiracy site to populate.
 
kalvado
Posts: 2817
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 12:42 pm

XRAYretired wrote:
kalvado wrote:
XRAYretired wrote:
NTSB are participants and have confirmed they have the access they require.

Fine difference is between having access to the data others obtained vs actually being in physical control, including ability to alter raw data before it is shared. Many posters complain US agencies didn't have the later.

If you and friends cant assimilate the information provided, no one can help you. Suggest find a conspiracy site to populate.

More like pointing out that remark starting this argument
patrickjp93 wrote:
Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions.

is a direct hint on something. Well, if the shoe fits...
 
Western727
Posts: 1773
Joined: Wed Jan 03, 2007 12:38 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 1:32 pm

https://www.usatoday.com/story/news/nat ... 392642002/

Former senior manager Ed Pierson is set to testify today (Wednesday 11 December). Excerpt:

Four months before the Lion Air crash, Pierson said he emailed the 737 general manager advising that the production line be shut down temporarily to allow teams to "regroup" in order to safely finish work on the planes. In the same missive, he wrote, "for the first time in my life, I'm sorry to say that I'm hesitant about putting my family on a Boeing airplane."

...ouch.
Jack @ AUS
 
pune
Posts: 389
Joined: Tue Feb 12, 2019 9:18 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 1:59 pm

Western727 wrote:
https://www.usatoday.com/story/news/nation/2019/12/10/boeing-warned-safety-quality-lapses-ex-manager-says/4392642002/

Former senior manager Ed Pierson is set to testify today (Wednesday 11 December). Excerpt:

Four months before the Lion Air crash, Pierson said he emailed the 737 general manager advising that the production line be shut down temporarily to allow teams to "regroup" in order to safely finish work on the planes. In the same missive, he wrote, "for the first time in my life, I'm sorry to say that I'm hesitant about putting my family on a Boeing airplane."

...ouch.


and apart from this, wasn't there an engineer who took his fifth amendment rights. I am sure he has more insight to the story than we will ever know. Maybe American posters know of instances where a person's fifth amendment civil liberties rights were considered less than public safety . Maybe American law or/and jusrispudence has something to that effect. I know it is the wrong way to do things because then you will be in effect be making fifth amendment ineffective and the state could use the same excuse for taking whistleblower identity etc. or any other data which is private data and not meant for public consumption :(
 
User avatar
PixelFlight
Posts: 1019
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Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:00 pm

kalvado wrote:
XRAYretired wrote:
kalvado wrote:
Fine difference is between having access to the data others obtained vs actually being in physical control, including ability to alter raw data before it is shared. Many posters complain US agencies didn't have the later.

If you and friends cant assimilate the information provided, no one can help you. Suggest find a conspiracy site to populate.

More like pointing out that remark starting this argument
patrickjp93 wrote:
Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions.

is a direct hint on something. Well, if the shoe fits...

On ET302, the MCAS was immediately suspected because of the real time ADS-B data recorded by multiples organisations. The ET302 FDR data released in the preliminary report perfectly confirm the ADB-B data. Good luck to anyone that can spot a conspiracy alteration of the ET302 FDR data in that case, as it have to match the independently collected real-time ADS-B data, in addition to the information in the CVR... Not counting that the FDR data is composed of a lots of parameters that need to be keep in coherency :scratchchin:

"1.11.1 DIGITAL FLIGHT DATA RECORDER
The aircraft was fitted with a FA2100 NAND DFDR manufactured by L3-com with part number
2100-4945-22 and serial number 001217995."

"On 11 March 2019, the DFDR was recovered from the accident site by the AIB. The DFDR chassis
with the Crash Survivable Memory Unit (CSMU) attached were transported to the French BEA
recorder facility for data downloading. The recorder read-out was performed by BEA (Bureau
d’Enquête Analyse pour la sécurité de l’aviation civile) investigators for the Ethiopian Accident
Investigation Bureau (AIB) under the authority of Ethiopian investigators with the participation of
the U.S National Transportation Safety Board (NTSB), The Boeing Company, U.S Federal Aviation
Administration (FAA) and EASA.
"

"The memory unit recorded 1790 parameters and approximately 73 hours of aircraft operation, and
contained 16 flights, including the accident flight."
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
kalvado
Posts: 2817
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:04 pm

PixelFlight wrote:
kalvado wrote:
XRAYretired wrote:
If you and friends cant assimilate the information provided, no one can help you. Suggest find a conspiracy site to populate.

More like pointing out that remark starting this argument
patrickjp93 wrote:
Given Ethiopian's unwillingness to turn over the FDR and documentation for weeks after discovery, I don't trust their conclusions.

is a direct hint on something. Well, if the shoe fits...

On ET302, the MCAS was immediately suspected because of the real time ADS-B data recorded by multiples organisations. The ET302 FDR data released in the preliminary report perfectly confirm the ADB-B data. Good luck to anyone that can spot a conspiracy alteration of the ET302 FDR data in that case, as it have to match the independently collected real-time ADS-B data, in addition to the information in the CVR... Not counting that the FDR data is composed of a lots of parameters that need to be keep in coherency :scratchchin:

"1.11.1 DIGITAL FLIGHT DATA RECORDER
The aircraft was fitted with a FA2100 NAND DFDR manufactured by L3-com with part number
2100-4945-22 and serial number 001217995."

"On 11 March 2019, the DFDR was recovered from the accident site by the AIB. The DFDR chassis
with the Crash Survivable Memory Unit (CSMU) attached were transported to the French BEA
recorder facility for data downloading. The recorder read-out was performed by BEA (Bureau
d’Enquête Analyse pour la sécurité de l’aviation civile) investigators for the Ethiopian Accident
Investigation Bureau (AIB) under the authority of Ethiopian investigators with the participation of
the U.S National Transportation Safety Board (NTSB), The Boeing Company, U.S Federal Aviation
Administration (FAA) and EASA.
"

"The memory unit recorded 1790 parameters and approximately 73 hours of aircraft operation, and
contained 16 flights, including the accident flight."

By the way: some "satellite data" was mentioned as a reason to actually ground MAX in the days after the crash, before recorders were read. Was it ever clarified what was that about?
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:27 pm

https://www.channelstv.com/2019/12/11/b ... ion-chief/
https://uk.reuters.com/article/uk-boein ... YF18E?il=0

Dickson speaking before the hearing reportedly - 'won't be cleared to fly before 2020'-. Other officials reportedly implied February is now the likely timeframe.

Additionally, Dickson quoted as saying there are 10 or 11 milestones to yet be reached.

With a bit of luck he will list them this afternoon. Anyone care to speculate before hand?

Ray
 
LondonAero
Posts: 29
Joined: Tue Aug 06, 2019 4:55 pm

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:27 pm

Sounds like there is still a lot of wood to chop...

https://www.cnbc.com/video/2019/12/11/f ... k-box.html
 
VS11
Posts: 1661
Joined: Mon Jul 02, 2001 6:34 am

Re: Boeing 737MAX Grounded Worldwide Q4 2019

Wed Dec 11, 2019 2:27 pm

Boeing 737 Max Certification to Extend Into 2020, FAA Chief Says

From Bloomberg:
https://www.bloomberg.com/news/articles ... nd=premium

"....Federal Aviation Administration chief Stephen Dickson said that the plane, which has been grounded worldwide since March, will not be certified to fly this year, dashing Boeing’s hopes of getting the popular family of planes back in the air in 2019.
“If you do the math, it’s going to extend into 2020,” Dickson told CNBC Wednesday before he is expected to testify before a congressional panel. “We’re going to do it diligently because safety is absolutely our priority with this airplane...”

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