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morrisond
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 2:40 pm

kalvado wrote:
dagKentWA wrote:
kalvado wrote:
You keep forgetting that the very root cause is aerodynamic instability of the airframe. And since MCAS activation itself is a sign that there is an emergency going on - we're talking about handling emergency on top of emergency - and basically be akin of juggler skill, as those professionally deal with instabilities.
Sure, anything can be trained. A day in a sim on a weekly basis should provide ample familiraity with the situation, but I suspect airlines would be reluctant to do the right thing..


No. The root cause is that Boeing's customers wanted a plane that flew like the NG, so that they would not have to do additional training. To make the plane fly like an NG, MCAS was required, because yes, the plane flew differently as a result of the larger engines and the required change in CoG and the resulting tendency of the plane to pitch up while climbing & accelerating. But no one has ever proven that the plane was inherently unstable, only that it flew differently than the NG. And if a pilot knows how to fly, they can learn how to handle the aerodynamic characteristics of a particular model of plane.

Wrong. Stick force reversal was acknowledged by Boeing - "although it is just a little bit". There is a specific FAR explicitly prohibiting that, period. And there is a pretty good reason why. MAX is not certifiable without MCAS, training or not. Full stop. "Just a little bit" excuse is like saying there was no rape as he only went a quater inch deep.

What made the story worse is not disclosing MCAS to pilots - which was indeed for commonality reasons so that NG pilots don't have to be trained to deal with a new safety system.


No - it was stick force lightening - not reversal as in going negative - that would never be allowed. There is a big difference.
 
Noshow
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 3:46 pm

Stick force lightening is not allowed when approaching a stall in manual flight and with flaps up. Which is said to be what happens here. The counter-force used by MCAS via trim and horizontal stabilizer seems to be quite powerful.
 
djpearman
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 4:14 pm

jwjsamster wrote:
I'm sorry if this has been answered already, but will Boeing's fix require separate certification of the MAX aircraft from the NGs?

Thank you


Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.
 
kalvado
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 4:20 pm

morrisond wrote:
kalvado wrote:
dagKentWA wrote:

No. The root cause is that Boeing's customers wanted a plane that flew like the NG, so that they would not have to do additional training. To make the plane fly like an NG, MCAS was required, because yes, the plane flew differently as a result of the larger engines and the required change in CoG and the resulting tendency of the plane to pitch up while climbing & accelerating. But no one has ever proven that the plane was inherently unstable, only that it flew differently than the NG. And if a pilot knows how to fly, they can learn how to handle the aerodynamic characteristics of a particular model of plane.

Wrong. Stick force reversal was acknowledged by Boeing - "although it is just a little bit". There is a specific FAR explicitly prohibiting that, period. And there is a pretty good reason why. MAX is not certifiable without MCAS, training or not. Full stop. "Just a little bit" excuse is like saying there was no rape as he only went a quater inch deep.

What made the story worse is not disclosing MCAS to pilots - which was indeed for commonality reasons so that NG pilots don't have to be trained to deal with a new safety system.


No - it was stick force lightening - not reversal as in going negative - that would never be allowed. There is a big difference.

"Reversal" means reversal of force gradient, negative first derivative of the force. Which is exactly what you describe and which is explicitly prohibited as it equates to instability of control loop.
 
morrisond
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 5:39 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
Wrong. Stick force reversal was acknowledged by Boeing - "although it is just a little bit". There is a specific FAR explicitly prohibiting that, period. And there is a pretty good reason why. MAX is not certifiable without MCAS, training or not. Full stop. "Just a little bit" excuse is like saying there was no rape as he only went a quater inch deep.

What made the story worse is not disclosing MCAS to pilots - which was indeed for commonality reasons so that NG pilots don't have to be trained to deal with a new safety system.


No - it was stick force lightening - not reversal as in going negative - that would never be allowed. There is a big difference.

"Reversal" means reversal of force gradient, negative first derivative of the force. Which is exactly what you describe and which is explicitly prohibited as it equates to instability of control loop.


You may think that is what it means - but anyone in Aviation will take it as meaning that once you go past a certain point with the controls it won't require anymore force to keep pulling - the controls will help you and go negative force.

https://en.wikipedia.org/wiki/Control_reversal
 
kalvado
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 6:15 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

No - it was stick force lightening - not reversal as in going negative - that would never be allowed. There is a big difference.

"Reversal" means reversal of force gradient, negative first derivative of the force. Which is exactly what you describe and which is explicitly prohibited as it equates to instability of control loop.


You may think that is what it means - but anyone in Aviation will take it as meaning that once you go past a certain point with the controls it won't require anymore force to keep pulling - the controls will help you and go negative force.

https://en.wikipedia.org/wiki/Control_reversal

Well, since you asked...
he flight controls reverse themselves in a way that is not intuitive, so pilots may not be aware of the situation and therefore provide the wrong inputs

Given same applied stick force, aircraft would - counter-intuitively - get increased pitch input past some point. Any further questions?
 
jwjsamster
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 6:28 pm

djpearman wrote:
jwjsamster wrote:
I'm sorry if this has been answered already, but will Boeing's fix require separate certification of the MAX aircraft from the NGs?

Thank you


Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.



Oh wow, thank you for the update, I guess that means that Boeing will need to compensate customers for the training as well as lost revenue due to the grounding. Either way it's going to sting.

I know this is slightly off topic but is Boeing pursuing a single certification for the new 777X with current gen 777s? How will this news impact that?
 
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Stitch
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 6:53 pm

jwjsamster wrote:
I know this is slightly off topic but is Boeing pursuing a single certification for the new 777X with current gen 777s? How will this news impact that?


Last I heard is that the plan is to do an Amended Type Certificate, adding the 777-9 to the existing 777 Type Certificate (which currently includes the -200, -300, -200ER, -200LR, -300ER and Freighter).
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 8:08 pm

iamlucky13 wrote:
The words and the actions are consistent, but based on flawed information. After the first crash, Boeing and the regulators believed the plane could be operated safely despite the issue if crews were more explicitly aware there could be a need to follow a runaway stabilizer procedure as an interim mitigation until a permanent fix was ready. Those was their words. They allowed it to continue operating after the Lionair crash. That was their action.

The real problem is the mistakes in the risk analysis that concluded pilot actions to counter a fault were reasonable and sufficient for the conditions that would be present if a fault occurred. That led to the conclusion redundancy was not required in order to prevent a fault, rather than just assure it was rare. They also failed to re-analyze the risk as the design evolved to allow more stabilizer travel due to MCAS. Those mistakes were not resolved when the grounding questions were first asked, so the same mistaken risk analysis led to the same mistaken conclusion.

Some time between the first and second crashes Boeing decided they could not rely on a crew to deal with multiple MCAS activations and began developing a fix for this case, one that was said to be weeks away from release at the time of the second crash. As sgrow787 may say, either MCAS was broken or it was not. I think we can all agree it was broken, no? Surely them working on a fix tells us they knew it was. Given this, as I wrote earlier,

Revelation wrote:

Either they didn't understand the root cause and were working on a superficial fix, or they did understand the root cause and were deliberately avoiding the expense of a full fix by going forward with a superficial fix. One path suggests incompetence, the other path suggests sacrificing safety for profits. Either way there are some lessons to be learned here, yet the FAA IG report is silent on all of this.

It's really hard to understand how you could analyze the problem well enough to develop a fix without understanding the root cause. Regardless, the real issue I'm raising is the FAA IG report doesn't go into this at all.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 8:43 pm

jwjsamster wrote:
djpearman wrote:
jwjsamster wrote:
I'm sorry if this has been answered already, but will Boeing's fix require separate certification of the MAX aircraft from the NGs?

Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.

Oh wow, thank you for the update, I guess that means that Boeing will need to compensate customers for the training as well as lost revenue due to the grounding. Either way it's going to sting.

I think this is a bit off the mark.

FAA issued an Order of Prohibition saying the MAX could no longer be operated ( ref: https://www.faa.gov/news/updates/media/CAN-2019-05.pdf ) but did not change its certification status. It's still a certified aircraft, but all US operators are prohibited from operating it, and of course other regulators made similar announcements.

MAX always required differences training with respect to NG but it could be accomplished on an iPad so did not require sim training. However here we're talking about airman certification not aircraft certification.

When all the training requirements etc are finalized the FAA will issue an Airworthiness Directive that will lift the prohibition. It will also officially state the new airmen training requirements. We are also told FAA will perform individual inspection of each MAX before it can return to service as opposed to delegating inspections to Boeing.

MAX was and still will be a model on the 737 Type Certificate just like 779 will be a model on the 777 Type Certificate.

Airmen will need certification by model, that's the same as always. Southwest has a single aircraft type, 737, with two different models NG and MAX, and this will not change. FAA did not allow airmen to remain current on more than two at a time which is why the Classics had to leave when the MAX showed up.

And yes, the additional training MAX pilots will need will be costly and take time. I'm sure it's one element of whatever agreements Boeing and WN have reached regarding MAX compensation.

Yet once the pilots are through the training nothing changes with regard to their ability to fly MAX vs NG so nothing changes about WN's ability to schedule pilots based on their certifications so nothing changes about WN's business model except the need for longer and more expensive training when pilots are transitioning from NG to MAX which is a once per pilot expense.
Last edited by Revelation on Wed Jul 15, 2020 8:51 pm, edited 2 times in total.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
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morrisond
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 15, 2020 8:43 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
"Reversal" means reversal of force gradient, negative first derivative of the force. Which is exactly what you describe and which is explicitly prohibited as it equates to instability of control loop.


You may think that is what it means - but anyone in Aviation will take it as meaning that once you go past a certain point with the controls it won't require anymore force to keep pulling - the controls will help you and go negative force.

https://en.wikipedia.org/wiki/Control_reversal

Well, since you asked...
he flight controls reverse themselves in a way that is not intuitive, so pilots may not be aware of the situation and therefore provide the wrong inputs

Given same applied stick force, aircraft would - counter-intuitively - get increased pitch input past some point. Any further questions?


Nope - you still don't understand what control reversal means. I'm not going to try to correct it anymore.
 
TaromA380
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Thu Jul 16, 2020 8:08 pm

By the way, isn't it dubious that ET final crash report is nowhere to be seen ?
 
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aerolimani
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Thu Jul 16, 2020 10:01 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

You may think that is what it means - but anyone in Aviation will take it as meaning that once you go past a certain point with the controls it won't require anymore force to keep pulling - the controls will help you and go negative force.

https://en.wikipedia.org/wiki/Control_reversal

Well, since you asked...
he flight controls reverse themselves in a way that is not intuitive, so pilots may not be aware of the situation and therefore provide the wrong inputs

Given same applied stick force, aircraft would - counter-intuitively - get increased pitch input past some point. Any further questions?


Nope - you still don't understand what control reversal means. I'm not going to try to correct it anymore.

It’s impressive that you posted the link to the wiki article on control reversal which describes absolutely nothing that resembles what happens in the MAX, in terms of what requires the plane to have MCAS. If control reversal was the problem, the plane would start to drop its nose as the pilot kept pulling back on the column.

In the MAX, instead of the stick force steadily increasing as the pilot pulls back on the control column, and as AOA increases, at some point the force not only stops increasing, but starts decreasing. As kalvado put it, “reversal means reversal of force gradient.” As the pilot is pulling back, the plane should resist him/her more and more. If this doesn’t happen, or worse, if the force decreases as in the MAX, it risks the pilot too easily pulling the plane into a stall

The FAR exists for a good reason. In a non-FBW transport category aircraft, the plane needs to respond to pilot inputs in a natural and intuitive manner, in all types of flight conditions, including at the edge of the envelope. Whether you want to call it controls lightening or reversal of force gradient, it’s still a serious problem. Belittling problems is exactly the opposite of what needs to happen for us to have a safer aviation industry.
 
iamlucky13
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 5:34 am

Revelation wrote:
iamlucky13 wrote:
The words and the actions are consistent, but based on flawed information. After the first crash, Boeing and the regulators believed the plane could be operated safely despite the issue if crews were more explicitly aware there could be a need to follow a runaway stabilizer procedure as an interim mitigation until a permanent fix was ready. Those was their words. They allowed it to continue operating after the Lionair crash. That was their action.

The real problem is the mistakes in the risk analysis that concluded pilot actions to counter a fault were reasonable and sufficient for the conditions that would be present if a fault occurred. That led to the conclusion redundancy was not required in order to prevent a fault, rather than just assure it was rare. They also failed to re-analyze the risk as the design evolved to allow more stabilizer travel due to MCAS. Those mistakes were not resolved when the grounding questions were first asked, so the same mistaken risk analysis led to the same mistaken conclusion.

Some time between the first and second crashes Boeing decided they could not rely on a crew to deal with multiple MCAS activations and began developing a fix for this case, one that was said to be weeks away from release at the time of the second crash. As sgrow787 may say, either MCAS was broken or it was not. I think we can all agree it was broken, no? Surely them working on a fix tells us they knew it was. Given this, as I wrote earlier,

Revelation wrote:

Either they didn't understand the root cause and were working on a superficial fix, or they did understand the root cause and were deliberately avoiding the expense of a full fix by going forward with a superficial fix. One path suggests incompetence, the other path suggests sacrificing safety for profits. Either way there are some lessons to be learned here, yet the FAA IG report is silent on all of this.

It's really hard to understand how you could analyze the problem well enough to develop a fix without understanding the root cause. Regardless, the real issue I'm raising is the FAA IG report doesn't go into this at all.


Yes, it was broken and they knew it after the Lionair crash. By broken, I don't inherently mean an entirely unacceptable state, but rather in this case the risk was thought to be in between a level that was always acceptable and a level that is never acceptable. It was believed the risk could be tolerated for a limited duration of operations, as it was considered highly unlikely that the combination of another MCAS fault would combine with a pilot who, with benefit of the new information provided in an Airworthiness Directive after the Lionair crash, would be unable to recover from an MCAS fault. Hence, the aircraft was not grounded, but a fix was necessary to control the cumulative risk.

As I observed above, the risk level of continued operation was tragically proven to be unacceptable. As the original risk analysis was reviewed in detail, it started to become understood that not only should the risk of unintended MCAS activation been ranked as more severe than originally concluded, but the risk should have been re-evaluated when changes were made to the magnitude of stabilizer travel, and it should have been caught that MCAS might operate multiple times. Per previous reporting, it appears the FAA was just starting to recognize the mistakes of the risk analysis at the time of the Ethiopian crash.

I also want to note that the scenario was not binary as you present. You can understand the root cause and use a superficial fix (like the AD), not to avoid a more comprehensive fix, but as an interim action to be followed by one or multiple additional rounds of improvement. You could also not understand a root cause, but know the effects well enough to mitigate them while you continue to investigate the root cause. I have not read the IG report in detail, but I have familiarized myself with it, and the actual logic stated in the IG report was:

"FAA’s risk analysis also indicated that the AD mitigated the risk sufficiently enough to allow continued aircraft operation for a limited period of time, until July 2019, while the software fix was being developed and implemented on the existing fleet. As a result of the Lion Air accident, Boeing agreed to begin developing software design changes to MCAS. The initial proposal for the software fix would revise MCAS to compare data from both AOA sensors and limit its ability to activate multiple times."

I emphasize "initial proposal" because making a fix that could be implemented quickly did not preclude making further improvements later if deemed necessary. The deadline was July, but the initially proposed fix was intended to be ready by April.
Last edited by iamlucky13 on Fri Jul 17, 2020 5:40 am, edited 1 time in total.
 
iamlucky13
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 5:39 am

sgrow787 wrote:
iamlucky13 wrote:
You're not making clear what your point is. We know there was a coincidence of circumstances lining up to lead to the crashes despite multiple layers of safety. That is the case with most crashes and not in question here.

The words and the actions are consistent, but based on flawed information. After the first crash, Boeing and the regulators believed the plane could be operated safely despite the issue if crews were more explicitly aware there could be a need to follow a runaway stabilizer procedure as an interim mitigation until a permanent fix was ready. Those was their words. They allowed it to continue operating after the Lionair crash. That was their action.

The real problem is the mistakes in the risk analysis that concluded pilot actions to counter a fault were reasonable and sufficient for the conditions that would be present if a fault occurred. That led to the conclusion redundancy was not required in order to prevent a fault, rather than just assure it was rare. They also failed to re-analyze the risk as the design evolved to allow more stabilizer travel due to MCAS. Those mistakes were not resolved when the grounding questions were first asked, so the same mistaken risk analysis led to the same mistaken conclusion.

When the second crash happened, they limited their words for 2 days while they started the action of collecting and analyzing the data. The media, writing to an audience that doesn't even understand simple words like "literally," had no difficulty spinning the FAA's technical words that they hadn't determined "systemic performance issues" as if the FAA were declaring summarily that there was no problem. A few less official comments were actually rather dismissive, but those comments were not the basis of the FAA decisions. However, the actual text of the [url="https://www.faa.gov/news/updates/media/CAN_2019_03.pdf"]CANIC[/url] issued the day of the accident indicated they were investigating what the problem is and whether it was related to the previous crash:
External reports are drawing similarities between this accident and the Lion Air Flight 610 accident on October 29, 2018. However, this investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions.


Somewhere around 2-1/2 days after the crash, before the flight data recorders had even been read, but once they had a look at the elevation data broadcast by the aircraft, and received the report from the investigators on the ground that the horizontal stabilizer jack screw was in an extreme nose down position, they concluded the evidence presented significant concern the crashes were related, and they grounded the MAX.


Words and actions with respect to the Max design and certification. You keep wanting to talk about the crashes and the root cause of them. How much clearer do I need to be??


No, I do not keep wanting to talk about the crashes and the root cause, which is why I specifically said I was limited my comments on the cause. Rather, my posts have each time been topical to the posts I have been quoting, although keeping aware of one of Revelation's posts a little ways upthread that spawned several of the tangents that have arisen.

If clarity is being lost in a discussion, it helps to step back and restate your thesis.
 
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Chipmunk1973
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 6:59 am

In terms of the total fix package which roughly is software updates, wiring harnesses, and a few other things that are currently escaping my brain, do we know roughly how many person hours per aircraft it will require?

I’d be of the opinion that it’d be a multi person team performing the updates as well as relevant post install testing. To me it seems like there is quite a bit of work to be done on each plane and there are hundreds out there.

And to add the icing to the cake, it still needs FAA inspection and sign off.

There’s going to be a lot of busy people me thinks.
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djpearman
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 11:57 am

Revelation wrote:
jwjsamster wrote:
djpearman wrote:
Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.

Oh wow, thank you for the update, I guess that means that Boeing will need to compensate customers for the training as well as lost revenue due to the grounding. Either way it's going to sting.

I think this is a bit off the mark.

FAA issued an Order of Prohibition saying the MAX could no longer be operated ( ref: https://www.faa.gov/news/updates/media/CAN-2019-05.pdf ) but did not change its certification status. It's still a certified aircraft, but all US operators are prohibited from operating it, and of course other regulators made similar announcements.

MAX always required differences training with respect to NG but it could be accomplished on an iPad so did not require sim training. However here we're talking about airman certification not aircraft certification.

When all the training requirements etc are finalized the FAA will issue an Airworthiness Directive that will lift the prohibition. It will also officially state the new airmen training requirements. We are also told FAA will perform individual inspection of each MAX before it can return to service as opposed to delegating inspections to Boeing.

MAX was and still will be a model on the 737 Type Certificate just like 779 will be a model on the 777 Type Certificate.


True, my remark is a bit off the mark - thanks for the corrections.

Yes, the MAX is not a different aircraft type but a model of the aircraft type 737. And while initially, the differences between NG and MAX were solely in pilot training, the presence of MCAS in the MAX and its significant influence on controlling the aircraft does make the MAX a more significant change compared to the NG than the NG compared to the classic. This primarily affects training requirements leading to the necessity of MAX-specific sim training, but, as far as I have read, is going to require changes to be made the aircraft in the form of a third AOA source as well as additional cockpit warning lights.

Revelation wrote:
Airmen will need certification by model, that's the same as always. Southwest has a single aircraft type, 737, with two different models NG and MAX, and this will not change. FAA did not allow airmen to remain current on more than two at a time which is why the Classics had to leave when the MAX showed up.

And yes, the additional training MAX pilots will need will be costly and take time. I'm sure it's one element of whatever agreements Boeing and WN have reached regarding MAX compensation.

Yet once the pilots are through the training nothing changes with regard to their ability to fly MAX vs NG so nothing changes about WN's ability to schedule pilots based on their certifications so nothing changes about WN's business model except the need for longer and more expensive training when pilots are transitioning from NG to MAX which is a once per pilot expense.


So, if a pilot is current on both MAX and NG, how does the recurring training apply? Does an OPC for the MAX include the NG as well? Do we have any information on that yet?

If it does, then Southwest and Ryanair would be fine, since they could train all pilots on the MAX and keep their single pilot pool that makes their operations so efficient. However, since Boeing spent most of 2019 fighting against dedicated MAX sim training, I'm guessing this is not the case.
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 12:26 pm

djpearman wrote:
Yes, the MAX is not a different aircraft type but a model of the aircraft type 737. And while initially, the differences between NG and MAX were solely in pilot training, the presence of MCAS in the MAX and its significant influence on controlling the aircraft does make the MAX a more significant change compared to the NG than the NG compared to the classic. This primarily affects training requirements leading to the necessity of MAX-specific sim training, but, as far as I have read, is going to require changes to be made the aircraft in the form of a third AOA source as well as additional cockpit warning lights.

I think this is right, but IMO going from Classic to NG was a probably a big jump too. It's wing was pretty much all new in terms of airfoil and its engines had a bigger fan. Boeing tried to make the NG handle like the Classic to minimize the training delta and minimized systems changes too. That's what they were going for with MAX, but it turns out they played Jedi mind tricks not just on FAA and customers, but also on themselves, with tragic consequences for all.

djpearman wrote:
So, if a pilot is current on both MAX and NG, how does the recurring training apply? Does an OPC for the MAX include the NG as well? Do we have any information on that yet?

If it does, then Southwest and Ryanair would be fine, since they could train all pilots on the MAX and keep their single pilot pool that makes their operations so efficient. However, since Boeing spent most of 2019 fighting against dedicated MAX sim training, I'm guessing this is not the case.

That's a good point, we probably should wait for details.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 17, 2020 9:40 pm

iamlucky13 wrote:
I also want to note that the scenario was not binary as you present. You can understand the root cause and use a superficial fix (like the AD), not to avoid a more comprehensive fix, but as an interim action to be followed by one or multiple additional rounds of improvement. You could also not understand a root cause, but know the effects well enough to mitigate them while you continue to investigate the root cause. I have not read the IG report in detail, but I have familiarized myself with it, and the actual logic stated in the IG report was:

"FAA’s risk analysis also indicated that the AD mitigated the risk sufficiently enough to allow continued aircraft operation for a limited period of time, until July 2019, while the software fix was being developed and implemented on the existing fleet. As a result of the Lion Air accident, Boeing agreed to begin developing software design changes to MCAS. The initial proposal for the software fix would revise MCAS to compare data from both AOA sensors and limit its ability to activate multiple times."

I emphasize "initial proposal" because making a fix that could be implemented quickly did not preclude making further improvements later if deemed necessary. The deadline was July, but the initially proposed fix was intended to be ready by April.

I've read the IG report and can agree this is one of the key sections, and in particular the last sentence.

When I was thinking of "superficial fix" I was thinking of "limit its ability to activate multiple times". There's plenty of ways to do that in a superficial manner.

When I was thinking of "root cause" I was thinking of "compare data from both AOA". Once you realize you need to read both sensors someone in the loop has to realize both sensors need to be available thus the safety assessment immediately moves from "major" to "catastrophic" as per pg 28:

In this system safety assessment, Boeing identified potential failure scenarios
related to the horizontal stabilizer and evaluated their risk. Notably, Boeing
included a scenario in which there would be an “unintended MCAS activation.”
However, Boeing assigned this failure scenario the risk rating of “Major” under
normal flight operations, which meant that there was no requirement to provide
design redundancy (i.e., a requirement for MCAS to pull data from both external
AOA sensors on the 737 MAX 8, rather than relying on a single AOA sensor as the
system was designed). Such redundancy is required for the higher-risk rating of
catastrophic.


Boeing recognized that the risk of unintended MCAS activation could be more
severe under certain circumstances [b]if
the aircraft was operating outside of normal
flight parameters. [/b]However, the company adjusted its evaluation of this risk
based on statistical analysis showing it was unlikely that a typical flight would be
operating in those circumstances, and therefore unlikely that MCAS would
activate under these conditions.

This is something multiple people called out on earlier versions of this thread so you don't extraordinary insight to draw these conclusions. People looking into this in their spare time without access to detailed design info or crash data called it out early on.

Thing is, the aircraft was not operating outside of normal flight parameters i.e. the aircraft was not in a wind up turn. That should have ruled out the "adjustment" because the accident disproved its basis. The report goes on to say JATR found Boeing didn't even do the statistical analysis correctly so we can infer it should have been deemed catastrophic from the start.

The IG report doesn't speak at all to who/what/when/where/how FAA did their risk analysis at the time, i.e. "FAA’s risk analysis also indicated that the AD mitigated the risk sufficiently". It does say:

In January 2019, FAA initiated an internal review of the original MCAS certification
process. This was the first time FAA performed its own detailed analysis of MCAS,
and according to several FAA certification engineers, it was also the first time that
they were presented with a full picture of how MCAS worked.

That date is after the risk analysis was done, so it was done before (presumably anyone in) FAA had a full picture of how MCAS worked, and it's not clear if these "certification engineers" were the same people who did the risk assessment. If they were different people it's not clear if they reached out to those who did the analysis and said "time to update your analysis", the IG report doesn't tell us.

Again, all this happened after there was a crash, so one would hope everyone involved was doing their utmost to figure out exactly what happened.
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Sat Jul 18, 2020 7:21 am

Some of the 737MAX stored at RNT and BFI, taken last weekend

Image

Image

Image

Image

https://twitter.com/KPAE_Spotter/status ... 85408?s=20
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Sat Jul 18, 2020 2:29 pm

qf789 wrote:
Some of the 737MAX stored at RNT and BFI, taken last weekend

In the US we have a saying that is appropriate: "All dressed up, and nowhere to go".
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Sun Jul 19, 2020 2:18 am

Revelation wrote:
qf789 wrote:
Some of the 737MAX stored at RNT and BFI, taken last weekend

In the US we have a saying that is appropriate: "All dressed up, and nowhere to go".


"Oh, that magic feeling
Nowhere to go"
J. Lennon and P. McCartney
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Sun Jul 19, 2020 11:24 pm

Revelation wrote:
As sgrow787 may say, either MCAS was broken or it was not. I think we can all agree it was broken, no? Surely them working on a fix tells us they knew it was.


Depends on what you mean by "MCAS". If you include AOA sensor validation and cleanup within the MCAS subsystem, then yes, it was broken. If you mean "MCAS" as in the nature and authority of its activation during a perceived high-AOA event, then one can argue there's no supporting evidence given by Boeing that it's broken. Boeing hasn't shared the aerodynamic stability tables for the Max. However Transport Canada has given indication, at least to a degree, that MCAS isn't needed at all - per their request in Nov 2019 to remove MCAS from the Max altogether:

https://www.businessinsider.com/boeing- ... s%20report.

Boeing "working on a fix" to the FCC computer certainly involves a fix to the sensor redundancy (ie sensor validation and cleanup), which very well could be separate from the repeated MCAS activation, and the cyclic MCAS fixes.

If the MCAS repeated activation during a high-AOA event were needed for certification, what has changed since then and after the two crashes? The aerodynamics haven't changed. Nor have the size or type or location of the larger engines. Perhaps there's now a lot of pissed off regulators. And perhaps a lot of pissed off pilots. Maybe a compromise between a hack redundancy fix*** and the repeated activations that the manual trim wheel can't keep up with!?!?

***Eg, they can get the cross-side AOA data, but the frequency of that data isn't high/fast enough for the MCAS to respond in real-time to.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Sun Jul 19, 2020 11:50 pm

iamlucky13 wrote:
No, I do not keep wanting to talk about the crashes and the root cause, which is why I specifically said I was limited my comments on the cause. Rather, my posts have each time been topical to the posts I have been quoting, although keeping aware of one of Revelation's posts a little ways upthread that spawned several of the tangents that have arisen.

If clarity is being lost in a discussion, it helps to step back and restate your thesis.


Revelation stated upthread that Boeing simply failed to consider dual sensor redundancy altogether. The topic I started in response was - that Boeing knew they needed dual-sensor redundancy for MCAS. The discussion then got sidetracked by several posters, some taking issue with the cause of the crashes, some simple creating distraction (OEM does or doesn't ground planes), and some positing an end to the "Groundhog Day" discussion altogether.

Someone even offered that Airbus didn't ground their A330 after the AF447 and QF72 incidents, yet failed to include the fact that the A330 incidents happened 14 yrs after EIS. Compare that to the Lion Air crash within 2 yrs of the Max EIS.

No, clarity isn't being lost, it's being sidetracked.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 12:46 pm

djpearman wrote:
jwjsamster wrote:
I'm sorry if this has been answered already, but will Boeing's fix require separate certification of the MAX aircraft from the NGs?

Thank you


Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.


I think that is a little extreme. While there will be added cost for training (for those two likely absorbed by Boeing), the crews will still be able to fly both MAX and NG. For the business model, the advantage is that a crew can fly whatever aircraft is assigned to their flight. That will still exist. Before the grounding, there was still training for an NG pilot to be able to fly the MAX, it just wasn't full simulator training.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 1:59 pm

sgrow787 wrote:
Revelation wrote:
As sgrow787 may say, either MCAS was broken or it was not. I think we can all agree it was broken, no? Surely them working on a fix tells us they knew it was.


Depends on what you mean by "MCAS". If you include AOA sensor validation and cleanup within the MCAS subsystem, then yes, it was broken. If you mean "MCAS" as in the nature and authority of its activation during a perceived high-AOA event, then one can argue there's no supporting evidence given by Boeing that it's broken. Boeing hasn't shared the aerodynamic stability tables for the Max. However Transport Canada has given indication, at least to a degree, that MCAS isn't needed at all - per their request in Nov 2019 to remove MCAS from the Max altogether:

https://www.businessinsider.com/boeing- ... s%20report.

Boeing "working on a fix" to the FCC computer certainly involves a fix to the sensor redundancy (ie sensor validation and cleanup), which very well could be separate from the repeated MCAS activation, and the cyclic MCAS fixes.

If the MCAS repeated activation during a high-AOA event were needed for certification, what has changed since then and after the two crashes? The aerodynamics haven't changed. Nor have the size or type or location of the larger engines. Perhaps there's now a lot of pissed off regulators. And perhaps a lot of pissed off pilots. Maybe a compromise between a hack redundancy fix*** and the repeated activations that the manual trim wheel can't keep up with!?!?

***Eg, they can get the cross-side AOA data, but the frequency of that data isn't high/fast enough for the MCAS to respond in real-time to.

A sidetrack perhaps, but the leaked, context-lacking email from one Transport Canada employee should not be taken as the opinion of the agency. It is not. It doesn’t offer any substantial evidence as to the state of the aircraft. Probably the strongest evidence of problems is that, as far as we know, Boeing never asked for an exception to the regulation. Indeed, theY even began working on a fix before the second crash happened. To me, this offers more evidence as to the state of the aircraft than the leaked TC employee’s email.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 3:45 pm

aerolimani wrote:
morrisond wrote:
kalvado wrote:
Well, since you asked...

Given same applied stick force, aircraft would - counter-intuitively - get increased pitch input past some point. Any further questions?


Nope - you still don't understand what control reversal means. I'm not going to try to correct it anymore.

It’s impressive that you posted the link to the wiki article on control reversal which describes absolutely nothing that resembles what happens in the MAX, in terms of what requires the plane to have MCAS. If control reversal was the problem, the plane would start to drop its nose as the pilot kept pulling back on the column.

In the MAX, instead of the stick force steadily increasing as the pilot pulls back on the control column, and as AOA increases, at some point the force not only stops increasing, but starts decreasing. As kalvado put it, “reversal means reversal of force gradient.” As the pilot is pulling back, the plane should resist him/her more and more. If this doesn’t happen, or worse, if the force decreases as in the MAX, it risks the pilot too easily pulling the plane into a stall

The FAR exists for a good reason. In a non-FBW transport category aircraft, the plane needs to respond to pilot inputs in a natural and intuitive manner, in all types of flight conditions, including at the edge of the envelope. Whether you want to call it controls lightening or reversal of force gradient, it’s still a serious problem. Belittling problems is exactly the opposite of what needs to happen for us to have a safer aviation industry.


I'm quite aware that is what the issue on the MAX.

However Kalvado initially wrote "the flight controls reverse themselves". Which is quite different from a reversal of the force gradient and is explained by the Wiki on control reversal.

What Kalvado wrote implied an even larger problem than exists.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 4:38 pm

morrisond wrote:
aerolimani wrote:
morrisond wrote:

Nope - you still don't understand what control reversal means. I'm not going to try to correct it anymore.

It’s impressive that you posted the link to the wiki article on control reversal which describes absolutely nothing that resembles what happens in the MAX, in terms of what requires the plane to have MCAS. If control reversal was the problem, the plane would start to drop its nose as the pilot kept pulling back on the column.

In the MAX, instead of the stick force steadily increasing as the pilot pulls back on the control column, and as AOA increases, at some point the force not only stops increasing, but starts decreasing. As kalvado put it, “reversal means reversal of force gradient.” As the pilot is pulling back, the plane should resist him/her more and more. If this doesn’t happen, or worse, if the force decreases as in the MAX, it risks the pilot too easily pulling the plane into a stall

The FAR exists for a good reason. In a non-FBW transport category aircraft, the plane needs to respond to pilot inputs in a natural and intuitive manner, in all types of flight conditions, including at the edge of the envelope. Whether you want to call it controls lightening or reversal of force gradient, it’s still a serious problem. Belittling problems is exactly the opposite of what needs to happen for us to have a safer aviation industry.


I'm quite aware that is what the issue on the MAX.

However Kalvado initially wrote "the flight controls reverse themselves". Which is quite different from a reversal of the force gradient and is explained by the Wiki on control reversal.

What Kalvado wrote implied an even larger problem than exists.

Flight controls DO reverse themselves as increased control deflection results in reduced force - creating pilot's impression that they are doing an opposite thing - releasing yoke and reducing airfoil deflection. Actual movement is reverse to expected.
.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 5:10 pm

So, back to topic.

What is the latest with flight testing and progression of certification and ultimately, return to service?
Whatever
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 6:14 pm

FriscoHeavy wrote:
So, back to topic.

What is the latest with flight testing and progression of certification and ultimately, return to service?

It seems everyone is being pretty tight lipped. Remember we only heard of the FAA flights a few days before they happened. Seems both Boeing and FAA have done their best to keep their moths closed. Boeing's CEO gave an interview ( link in news/reference thread ) but it was about higher level issues such as changing the relationship between engineering and marketing rather than an update on the MAX RTS.
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Jul 20, 2020 9:20 pm

planecane wrote:
djpearman wrote:
jwjsamster wrote:
I'm sorry if this has been answered already, but will Boeing's fix require separate certification of the MAX aircraft from the NGs?

Thank you


Yes, that is what they have been working on since the grounding.

In my opinion, this severely damages the value of the 737, since single-aircraft airlines (Southwest, Ryanair) will no longer have a single aircraft type. That's their business model out the window.


I think that is a little extreme. While there will be added cost for training (for those two likely absorbed by Boeing), the crews will still be able to fly both MAX and NG. For the business model, the advantage is that a crew can fly whatever aircraft is assigned to their flight. That will still exist. Before the grounding, there was still training for an NG pilot to be able to fly the MAX, it just wasn't full simulator training.


Your last statement there is the crux of the matter. Before the crashes, the premise of the MAX was that it flew just like the NG, no sim training needed. Boeing insisted for several months that no sim training was going to be necessary, but eventually (quite rightly IMHO) were persuaded to change that stance. The necessity of sim training for NG pilots to fly the MAX does throw up the question, whether a pilot needs to keep refreshing his OPC for both models (NG and MAX). If the OPC for the MAX includes the NG, then the business model is still fully intact.

If, however, pilots need to keep current on both models (the more likely scenario now that MCAS has been revealed), then the business model takes a hit, since pilots will require more training in both NG and MAX simulators to be allowed to fly both models freely. Airlines need to track pilot training and, if not all pilots are current on both models, plan aircraft and pilots accordingly. Since sim training is going to be mandated for the MAX, I think the single-737 airline business model does take a hit - my statement of 'goes out the window' is somewhat extreme there, I agree, yes :)
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Tue Jul 21, 2020 2:09 pm

Res business model: If Boeing's mission was to build the best planes possible their profit margins were high enough to take the million dollar a plane hit to include SIMS training (although I remain bewildered that there is no training device between an iPad and a $15 million model). But Boeing's mission was to be a multi-billion dollar Wall Street darling. One notes that they have also failed at the later.
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Tue Jul 21, 2020 4:06 pm

frmrCapCadet wrote:
Res business model: If Boeing's mission was to build the best planes possible their profit margins were high enough to take the million dollar a plane hit to include SIMS training (although I remain bewildered that there is no training device between an iPad and a $15 million model). But Boeing's mission was to be a multi-billion dollar Wall Street darling. One notes that they have also failed at the later.

It reminds me of the old expression: "Fast, cheap, good: pick two!".
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Tue Jul 21, 2020 5:14 pm

Public given 45 to comment on max
https://twitter.com/dominicgates/status ... 33984?s=19

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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Tue Jul 21, 2020 6:11 pm

are there any updates on the lawsuit from Norwegian?

Edit, found it onLeehamnews! They want to return the max fleet to Boeing, 18 planes.


https://leehamnews.com/2020/07/21/hotr- ... more-34005

NAS also wants to return its 18 737-8s that were delivered but which have been grounded since March 2019 in the wake of two fatal MAX accidents with Lion Air and Ethiopian Airlines.

Norwegian filed claims for “in excess of $1bn.” It seeks court authority to rescind contracts for 110 MAX aircraft (including ones already delivered) and an unspecified number of 787s, including some already delivered.


Norwegian claims fraud, breach of contract and gross negligence by Boeing. It claims BCASE is charging for maintenance services not delivered.


55 Million per plane? Sounds a bit expensive?

Norwegian revealed that it paid more than $1bn for 18 MAXes delivered so far, or more than $55m per plane.
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 4:10 am

BEG2IAH wrote:
Reuters: Boeing 737 MAX not expected to fly before October, FAA preparing directive

https://www.reuters.com/article/us-boei ... SKCN24M2EE

I think the lede is:

The Federal Aviation Administration (FAA) said on Tuesday it plans to issue a proposed airworthiness directive for the Boeing 737 MAX in the “near future” to address changes made since the plane was grounded in March 2019 after two fatal crashes killed 346 people.

So the proposed version of the AD that will be one of the last steps of the ungrounding is coming soon.

And:

The FAA said the public will have 45 days to comment on “proposed design changes and crew procedures to mitigate the safety issues identified during the investigations that followed the Lion Air and Ethiopian Airlines accidents.”

And all the people reading this thread can have a go at telling FAA exactly what's wrong with it! :biggrin:

The article goes through all the other things that still need to happen before ungrounding (FSB+JOEB review of training stuff, public review of FSB review of JOEB report, FAA review of tech stuff, TAB review of FAA review, etc). Seems there are many gates to pass, but that's par for the course.

Seems much of this stuff will be made public, so we'll have some interesting stuff to discuss on this thread.
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 5:03 am

Revelation wrote:
[...snip...]
And all the people reading this thread can have a go at telling FAA exactly what's wrong with it! :biggrin:
[...snip...]

Speaking of which... did anybody here file an official comment with the FAA during the initial commenting period? I did, in May 2019, using the official "Comment Log" format, POC indicated in the request for comments was Aaron Perkins, of the Seattle Office. I never received any acknowledgment that they even received it, so I was wondering whether anybody else had done it and what the outcome was.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 5:59 am

IADFCO wrote:
Revelation wrote:
[...snip...]
And all the people reading this thread can have a go at telling FAA exactly what's wrong with it! :biggrin:
[...snip...]

Speaking of which... did anybody here file an official comment with the FAA during the initial commenting period? I did, in May 2019, using the official "Comment Log" format, POC indicated in the request for comments was Aaron Perkins, of the Seattle Office. I never received any acknowledgment that they even received it, so I was wondering whether anybody else had done it and what the outcome was.


If this is the correct AD, all 5 comments are posted.

https://www.regulations.gov/docket?D=FAA-2018-0960
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 7:18 am

The House is investigating! Let's see if this reveals anything?


https://www.reuters.com/article/us-boei ... SKCN24L2NT
U.S. lawmakers probing Boeing 737 MAX seek safety agency's employee survey records.

A U.S. House of Representatives Committee on Monday asked the Federal Aviation Administration to disclose details of an employee survey on the agency’s safety culture after two fatal crashes of Boeing 737 MAX airplanes raised questions about the agency’s actions.

FAA Administrator Steve Dickson was asked in a letter to share the outcome of the December 2019 survey that asked employees how they felt about a long-standing agency program called Organization Designation Authorization (ODA) that delegates some new airplane certification tasks to Boeing employees.

Peter DeFazio, who chairs the House Transportation and Infrastructure Committee, and Rick Larsen, who chairs a subcommittee on aviation, wrote that it was essential that FAA officials had “the authority, resources, willingness and support from FAA’s senior management to thoroughly and aggressively manage the ODA program.”

An FAA spokesman said the agency would respond to the lawmakers.

The letter, made public Monday after it was reported earlier by Reuters, noted that the Transportation Committee investigation has already determined that issues surrounding the ODA “played key contributing roles in the regrettable 737 MAX crashes of Lion Air flight 610 and Ethiopian Airlines flight 302.”
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 10:25 pm

taru wrote:
IADFCO wrote:
Revelation wrote:
[...snip...]
And all the people reading this thread can have a go at telling FAA exactly what's wrong with it! :biggrin:
[...snip...]

Speaking of which... did anybody here file an official comment with the FAA during the initial commenting period? I did, in May 2019, using the official "Comment Log" format, POC indicated in the request for comments was Aaron Perkins, of the Seattle Office. I never received any acknowledgment that they even received it, so I was wondering whether anybody else had done it and what the outcome was.


If this is the correct AD, all 5 comments are posted.

https://www.regulations.gov/docket?D=FAA-2018-0960


Thanks for the reply and the link, but no, it's not there.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Wed Jul 22, 2020 10:35 pm

Maybe it was a bit difficult!
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Thu Jul 23, 2020 2:06 am

IADFCO wrote:
taru wrote:
IADFCO wrote:
If this is the correct AD, all 5 comments are posted.

https://www.regulations.gov/docket?D=FAA-2018-0960


Thanks for the reply and the link, but no, it's not there.


If you saved a local copy of your comment, maybe you could post it here? Or create a thread to catch the comments for the new comment period??
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Fri Jul 24, 2020 10:39 am

News on the customer and supplier front! Customers remain committed, but.....lot's of discussions going on.

https://finance.yahoo.com/news/big-u-bo ... 42369.html

Two of Boeing Co's biggest commercial airline customers said on Thursday they are still committed to the 737 MAX despite delays in its return to flight and the coronavirus pandemic, though the head of Southwest Airlines said contracts need to be "completely reset."

American Airlines Chief Financial Officer Derek Kerr said the carrier is in "good discussions" with Boeing to finalize financing terms on 17 737 MAX jets that were to be delivered this year, adding that the airline still wants its full order for 100 MAX planes, over time. "We totally plan on taking those aircraft," Kerr said on a quarterly conference call. "Just when we take them is the discussion that we're having."

Southwest said it had agreed with Boeing to take no more than 48 aircraft through the end of 2021, although Boeing had projected the plane to return to service sooner. Southwest executives said they probably need fewer than those 48, and had not finalized any specifics with Boeing, giving them flexibility to continue monitoring demand for the next 18 months. CEO Gary Kelly added: "I think the way to visualize the situation with Boeing is that basically, where we go from here needs to be negotiated, period."



And while Southwest CFO believes mid December return to schedule is best case.
A mid-December return to its schedule is a "best-case scenario," Southwest CFO Tammy Romo said.


While CEO Gary Kelly seems to know more:
https://www.seattletimes.com/business/b ... -737-maxs/
Gary Kelly, CEO of Southwest Airlines, Boeing’s largest customer for the 737 MAX, said Thursday that while he hopes the plane will fly in passenger service in late December, “given the history of delays, it certainly could slide into the first quarter.”




Spirit has a bleak outlook, sharply downsized previous estimates!
https://www.cnbc.com/2020/07/23/key-boe ... -2022.html

Spirit shared a forecast with lenders that showed Boeing 737 deliveries this year of around 70 compared with a previous forecast of a little more than 200, while next year’s deliveries of the narrow-body plane would likely come in at less than half an earlier forecast of 400 planes, according to a Spirit presentation slide that was viewed by CNBC. In 2022, Boeing’s 737 deliveries were projected at fewer than 400 planes, a decline from a previous forecast of almost 500.

Those estimates are also lower than what some analysts are expecting. Jefferies, for example, estimated deliveries of the 737 at 370 in 2021 and 480 in 2022, according to a July 14 report. Deliveries are crucial to aircraft manufacturers and their suppliers because it’s when customers pay the bulk of the planes’ price.
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bennett123
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:04 pm

Taken from the news and reference thread.

https://www.faa.gov/news/media/attachme ... 8-3-20.pdf

How difficult will it be to make these changes to the aircraft already constructed.

How difficult will it be to make these changes to aircraft which are under construction.

How difficult will it be to make these changes to new build.
 
TropicalSky
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:13 pm

was this just posted today?

quote="bennett123"]Taken from the news and reference thread.

https://www.faa.gov/news/media/attachme ... 8-3-20.pdf

How difficult will it be to make these changes to the aircraft already constructed.

How difficult will it be to make these changes to aircraft which are under construction.

How difficult will it be to make these changes to new build.[/quote]
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:27 pm

Am reading the Notice of proposed rulemaking (NPRM) for a Boeing 737 MAX airworthiness directive (AD) (PDF) which is now out.

Some observations:

The updated FCC software would also compare the inputs from the two sensors to
detect a failed AOA sensor. If the difference between the AOA sensor inputs is above a
calculated threshold,11 the FCC would disable the speed trim system (STS), including its
MCAS function, for the remainder of that flight
, and provide a corresponding indication
of such deactivation on the flight deck.

Looks like turning off MCAS passes muster, so pilots will have to find a way to cope with "negative force gradient" for the rest of that flight.

The FAA also proposes requiring an additional software update that would alert
the flightcrew to a disagreement between the two AOA sensors.
This disagreement
indicates certain AOA sensor failures or a significant calibration issue. The updated MDS
software would implement an AOA DISAGREE alert on all 737 MAX airplanes. Some
737 MAX airplanes were delivered without this alert feature, by error. While the lack of
an AOA DISAGREE alert is not an unsafe condition itself, the FAA is proposing to
mandate this software update to restore compliance with 14 CFR 25.1301 and because
the flightcrew procedures mandated by this AD now rely on this alert to guide flightcrew
action.
As a result of the changes proposed in this AD, differences between the two AOA
sensors greater than a certain threshold13 would cause an AOA DISAGREE alert on the
primary flight displays (PFDs).

AOA disagree is now not just something nice to have, it's now a part of the AFM.

Lots of checklist stuff:

  • FAA proposes to revise the Airspeed Unreliable checklist of the AFM
  • The Runaway Stabilizer checklist of the AFM is used when there is undesired movement of the airplane’s horizontal stabilizer. The FAA proposes revisions to the criteria for this checklist’s use
  • The Stabilizer Trim Inoperative checklist of the AFM would be revised
  • ... a non-normal checklist, called the Speed Trim Fail checklist, would be added to the AFM
  • FAA proposes adding the Stabilizer Out of Trim checklist to the AFM
  • FAA proposes to add an AOA Disagree checklist as a procedure to the AFM
  • FAA proposes to add the ALT Disagree checklist as a procedure to the AFM
  • The final checklist that the FAA proposes to add to the AFM is a new IAS Disagree checklist.

I guess we can see why Boeing caved in on sim training.

Under the current design, the STAB OUT OF TRIM
light illuminates in flight to inform the flightcrew that the airplane’s autopilot is not
setting the horizontal stabilizer trim correctly. Under the new design, as part of the
aforementioned FCC software update, this light will now also illuminate on the ground,
to inform the flightcrew of a partial failure of a flight control computer.

Guess Boeing didn't want to add a "partial failure of a flight control computer" light so they just glommed on to the STAB OUT OF TRIM light.

Given the unprecedented length of time that the FAA has limited the operation of
these airplanes, and the importance of the flight control system to safety, the FAA
proposes to mandate an operational readiness flight after the design changes proposed by
this AD have been done, but prior to each airplane being introduced into service.

Not a surprise, right?

More later...
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:29 pm

TropicalSky wrote:
was this just posted today?

Yes:

Revelation wrote:
Looks like the Notice of proposed rulemaking (NPRM) for a Boeing 737 MAX airworthiness directive (AD) (PDF) is out.

Also, Preliminary Summary of the FAA’s Review of the Boeing 737 MAX (PDF) is available as well.

Today, the FAA sent a notice of proposed rulemaking (NPRM) for a Boeing 737 MAX airworthiness directive (AD) (PDF) to the Office of the Federal Register for publication. The NPRM proposes mandating a number of design changes to address an identified unsafe condition. When the NPRM publishes in the Federal Register, a 45 day public comment period will begin. The FAA is posting the NPRM on its website today to enable the public to begin review early.

The FAA will also be placing the Preliminary Summary of the FAA’s Review of the Boeing 737 MAX (PDF) in the docket to assist with the review of the proposed AD.

Ref: https://www.faa.gov/news/updates/?newsId=93206
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
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Stitch
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:31 pm

bennett123 wrote:
How difficult will it be to make these changes to the aircraft already constructed.

How difficult will it be to make these changes to aircraft which are under construction.

How difficult will it be to make these changes to new build.


Well it gives projected labor timelines of up to 82 hours to perform the work on existing frames with almost all of that being the stabilizer wiring change. New builds will have the new stabilizer wiring from the start so no impact there. So outside of the wiring, everything else takes a couple hours in total plus another 40 hours of testing of the AOA.
 
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hilram
Posts: 753
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 8:50 pm

bennett123 wrote:
Taken from the news and reference thread.

https://www.faa.gov/news/media/attachme ... 8-3-20.pdf

How difficult will it be to make these changes to the aircraft already constructed.

How difficult will it be to make these changes to aircraft which are under construction.

How difficult will it be to make these changes to new build.

That’s it, I suppose. The MAX will never make money, like the Dreamliner it can only be masked as a moneymaker by means of creative “Program Accounting “. And when you can’t make money on your Bread and Butter, you’re in Big Trouble.

“Boeing is Too Big to Fail!” Dennis: “Hold my beer”
Flown on: A319, 320, 321, 332, 333, 343 | B732, 734, 735, 736, 73G, 738, 743, 744, 772, 77W | CRJ9 | BAe-146 | DHC-6, 7, 8 | F50 | E195 | MD DC-9 41, MD-82, MD-87
 
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Revelation
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Re: Boeing 737MAX Grounding, General Discussion Thread, Q3 2020

Mon Aug 03, 2020 9:05 pm

hilram wrote:
The MAX will never make money, like the Dreamliner it can only be masked as a moneymaker by means of creative “Program Accounting “. And when you can’t make money on your Bread and Butter, you’re in Big Trouble.

Right, so now it's about bringing in what revenue you can. #242 above indicates AA and WN are looking forward to RTS. The way forward is no different than it's been for a while now, do your best to achieve RTS as soon as you can.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
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