A future cockpit is something you can perfectly do in quiet times like this. Sort out different pressure group interests and get things certified. But this can be bolted on any new airplane whenever it is ready. So it is more a strategic topic separated from actual airliner concepts as long as they provide some onboard space for a cockpit. So the cockpit is not what defines the next program.
I see manned cockpits and datalinks for remote operations be installed in parallel for some time.

The airline industry is a global market. Boeing talking to the FAA is nice, but it is no longer enough. You want all regulators on board and they will want to hear the OEMs under their respective jurisdiction. The time when everybody simply rubber stamped the FAA´s decision are over. And in Russia or China it is anything but a quite time when it comes to airliner developments.

seahawk wrote:

The airline industry is a global market. Boeing talking to the FAA is nice, but it is no longer enough. You want all regulators on board and they will want to hear the OEMs under their respective jurisdiction. The time when everybody simply rubber stamped the FAA´s decision are over. And in Russia or China it is anything but a quite time when it comes to airliner developments.

They are most likely talking ton EASA too. Lets not forget it was from EASA's advice that they pushed the 777X and MAX10 back to 2023. So, it would be obvious they are going to play a major role on what they want to see from this cockpit design, dare i say even more than the FAA

Opus99 wrote:

seahawk wrote:

The airline industry is a global market. Boeing talking to the FAA is nice, but it is no longer enough. You want all regulators on board and they will want to hear the OEMs under their respective jurisdiction. The time when everybody simply rubber stamped the FAA´s decision are over. And in Russia or China it is anything but a quite time when it comes to airliner developments.

They are most likely talking ton EASA too. Lets not forget it was from EASA's advice that they pushed the 777X and MAX10 back to 2023. So, it would be obvious they are going to play a major role on what they want to see from this cockpit design, dare i say even more than the FAA

Agree, and it wasn't just "advise", EASA gave them a list of things they need to do to get EASA certification for MAX10:

- 737 MAX AOA Integrity Enhancement
- non-critical Systems Safety Analysis (SSA) updates and supplemental technical verifications
- safety analysis process updates
- Development Assurance process updates

Ref: #1297 above

I presume ""737 MAX Crew Alerting Human Factors evaluation" may also produce some work items for MAX10 certification too.

Revelation wrote:

Opus99 wrote:

seahawk wrote:

The airline industry is a global market. Boeing talking to the FAA is nice, but it is no longer enough. You want all regulators on board and they will want to hear the OEMs under their respective jurisdiction. The time when everybody simply rubber stamped the FAA´s decision are over. And in Russia or China it is anything but a quite time when it comes to airliner developments.

They are most likely talking ton EASA too. Lets not forget it was from EASA's advice that they pushed the 777X and MAX10 back to 2023. So, it would be obvious they are going to play a major role on what they want to see from this cockpit design, dare i say even more than the FAA

Agree, and it wasn't just "advise", EASA gave them a list of things they need to do to get EASA certification for MAX10:

- 737 MAX AOA Integrity Enhancement
- non-critical Systems Safety Analysis (SSA) updates and supplemental technical verifications
- safety analysis process updates
- Development Assurance process updates

Ref: #1297 above

I presume ""737 MAX Crew Alerting Human Factors evaluation" may also produce some work items for MAX10 certification too.

Exactly. Advice is more on the lighter side of the truth. I wonder if the FAA will ever get back to a place where they can dictate how things move in the world of certification because right now It seems as though EASA seems to be the main recipients of the email and the FAA is CCd in

Opus99 wrote:

Exactly. Advice is more on the lighter side of the truth. I wonder if the FAA will ever get back to a place where they can dictate how things move in the world of certification because right now It seems as though EASA seems to be the main recipients of the email and the FAA is CCd in

What I find interesting is right after the 2nd crash Boeing's CEO made a big deal of appointing a commission to look at its internal processes and how MAX complied with them and as one might expect everything was deemed to be in perfect order, now EASA is saying no, actually, your processes need updating, starting with Safety Analysis. I'm not sure why this seems to be flying under the media's radar, but regardless it is good that they are getting external scrutiny.

Revelation wrote:

Opus99 wrote:

Exactly. Advice is more on the lighter side of the truth. I wonder if the FAA will ever get back to a place where they can dictate how things move in the world of certification because right now It seems as though EASA seems to be the main recipients of the email and the FAA is CCd in

What I find interesting is right after the 2nd crash Boeing's CEO made a big deal of appointing a commission to look at its internal processes and how MAX complied with them and as one might expect everything was deemed to be in perfect order, now EASA is saying no, actually, your processes need updating, starting with Safety Analysis. I'm not sure why this seems to be flying under the media's radar, but regardless it is good that they are getting external scrutiny.

Few in the media know even the most foundational details about the type and scope of policies that aircraft manufacturers rely on to guide their work in compliance with regulations and maintain adherence to their certifications. It's not something the media has the foggiest clue how to report on.

To be frank, I don't think even the regulators or the manufacturers can really claim they have a full understanding of how all the multi-layered, interwoven, and sometimes seemingly conflicting processes work. Each person in a given organization tries to learn their own part of the processes. The people who own or work under the low level processes know they're controlled by higher level processes. The people who own the higher level processes try to keep the lower level processes aligned in the correct direction, and get input from the people who own the lower level processes to keep the higher level specific enough to be useful, but not so specific that it over-constrains different groups who need to follow them for different tasks.

I think it would be very hard for a commission looking at processes from the outside to really comprehend what they accomplish or what the gaps are. The people who own and use the processes have to be directly involved and have the time and the guidance to help ensure a process not only has a realistic ideal path, but also a realistic way of handling problems - eg, how will a given group determine when a change made after the completion of a safety assessment is significant enough to require a new safety assessment, and give them a concrete enough set of criteria to help management understand why a program is (usually reasonably) off plan and why it needs to accept being off plan and work through developing a new plan.

iamlucky13 wrote:

To be frank, I don't think even the regulators or the manufacturers can really claim they have a full understanding of how all the multi-layered, interwoven, and sometimes seemingly conflicting processes work. Each person in a given organization tries to learn their own part of the processes. The people who own or work under the low level processes know they're controlled by higher level processes. The people who own the higher level processes try to keep the lower level processes aligned in the correct direction, and get input from the people who own the lower level processes to keep the higher level specific enough to be useful, but not so specific that it over-constrains different groups who need to follow them for different tasks.

I think it would be very hard for a commission looking at processes from the outside to really comprehend what they accomplish or what the gaps are. The people who own and use the processes have to be directly involved and have the time and the guidance to help ensure a process not only has a realistic ideal path, but also a realistic way of handling problems - eg, how will a given group determine when a change made after the completion of a safety assessment is significant enough to require a new safety assessment, and give them a concrete enough set of criteria to help management understand why a program is (usually reasonably) off plan and why it needs to accept being off plan and work through developing a new plan.

No doubt managing such an endeavor is a huge challenge, but after the fact we have some pretty glaring problems to solve. Boeing admits MCAS put too much workload on the pilots and admits the decision to allow MCAS to operate with one active AoA sensor was made by one individual applying a non-documented industry rule of thumb. The 737 Chief Engineer admits he didn't know MCAS used only one AoA sensor and had multiple activation authority till he read about it in the media. None of their quality processes caught the flaws, mainly because their Safety Analysis was flawed and they found a way to categorize MCAS as not being a new function. The only good thing about the glaring nature of these problems is hopefully it will make them easier to fix.

https://leehamnews.com/2021/04/08/analy ... aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

In other words, Leeham knows nothing more than the rest of the aviation blogosphere.

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

An A310? or 767-200?

DartHerald wrote:

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

An A310? or 767-200?

If they base it on the NLT - at least the smallest version they say it’s 148M in length. That is 3M longer than a 321 and that’s shorter than a 757-200. Yes 200

Revelation wrote:

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

In other words, Leeham knows nothing more than the rest of the aviation blogosphere.

Pretty much...although they always say their “sources” tell them blah blah

Opus99 wrote:

Revelation wrote:

In other words, Leeham knows nothing more than the rest of the aviation blogosphere.

Pretty much...although they always say their “sources” tell them blah blah

I'm not a subscriber, but I think you'll find they often use spreadsheets to model what the aircraft should be, based on various assumptions.

The spreadsheets themselves aren't that bad, the dubious part is the assumptions behind the spreadsheets and the data being used as input.

If you look around here, the spreadsheets originated from an a.net user called Ferpe and were posted here, presumably he's tinkered more with them since.

Various members who find such computations enjoyable grabbed copies and played around with them, in particular to model various "what if" scenarios around A380-like aircraft.

Opus99 wrote:

Leeham talks about how they think NMA must be twin aisle. 3 family member. With one member being the size of the 321.

I think it needs to be three members (45m | 50m | 55m) , as well, since the 737-10 cannot get anywhere near the range of the A321XLR, but it will only be competitive against the A321XLR on the TATL-style missions. Anything shorter and I expect it will be far too heavy.

Opus99 wrote:

DartHerald wrote:

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

An A310? or 767-200?

If they base it on the NLT - at least the smallest version they say it’s 148M in length. That is 3M longer than a 321 and that’s shorter than a 757-200. Yes 200

By the way I meant FT not M

Stitch wrote:

Opus99 wrote:

Leeham talks about how they think NMA must be twin aisle. 3 family member. With one member being the size of the 321.

I think it needs to be three members (45m | 50m | 55m) , as well, since the 737-10 cannot get anywhere near the range of the A321XLR, but it will only be competitive against the A321XLR on the TATL-style missions. Anything shorter and I expect it will be far too heavy.

And that is where I have issues. Wouldn’t it be better if it could compete with 321 a bit more? I understand not every aircraft can do everything but I think it would need to be a bit more flexible than that for the business case to close

Opus99 wrote:

And that is where I have issues. Wouldn’t it be better if it could compete with 321 a bit more? I understand not every aircraft can do everything but I think it would need to be a bit more flexible than that for the business case to close

The 737-10 can play with the A321 on short-to-medium (so NA TCON and intra-Europe), so the NMA-5 would cover the long-haul (TATL / North-to-South Asia) markets the 737-10 cannot.

NMA-6 and NMA-7 would be optimized for longer stage-lengths with a significant payload advantage over the A321XLR and likely lower CASM because of that extra usable capacity. So I expect it is NMA-6 and NMA-7 that need to really make their business cases (as a 767-300 / A330-200 replacement) and the NMA-5 will just be there as a gap-filler.

Stitch wrote:

Opus99 wrote:

And that is where I have issues. Wouldn’t it be better if it could compete with 321 a bit more? I understand not every aircraft can do everything but I think it would need to be a bit more flexible than that for the business case to close

The 737-10 can play with the A321 on short-to-medium (so NA TCON and intra-Europe), so the NMA-5 would cover the long-haul (TATL / North-to-South Asia) markets the 737-10 cannot.

NMA-6 and NMA-7 would be optimized for longer stage-lengths with a significant payload advantage over the A321XLR and likely lower CASM because of that extra usable capacity. So I expect it is NMA-6 and NMA-7 that need to really make their business cases (as a 767-300 / A330-200 replacement) and the NMA-5 will just be there as a gap-filler.

I agree. It makes more sense aiming for gap above current A321neo rather than try to be a better MAX10 or A321neo.

Revelation wrote:

Stitch wrote:

Opus99 wrote:

And that is where I have issues. Wouldn’t it be better if it could compete with 321 a bit more? I understand not every aircraft can do everything but I think it would need to be a bit more flexible than that for the business case to close

The 737-10 can play with the A321 on short-to-medium (so NA TCON and intra-Europe), so the NMA-5 would cover the long-haul (TATL / North-to-South Asia) markets the 737-10 cannot.

NMA-6 and NMA-7 would be optimized for longer stage-lengths with a significant payload advantage over the A321XLR and likely lower CASM because of that extra usable capacity. So I expect it is NMA-6 and NMA-7 that need to really make their business cases (as a 767-300 / A330-200 replacement) and the NMA-5 will just be there as a gap-filler.

I agree. It makes more sense aiming for gap above current A321neo rather than try to be a better MAX10 or A321neo.

Agreed - As Airbus's response will most likely be a stretched A322NEO - that should be at least the base size. I think the rumours for A322 are A321 plus another 3 rows so call it 48M in length. An equivalent capacity 7W NMA would be about 6-7M shorter call it about 42M - plus add a bit if you want it a touch bigger - not far off of Stitch's 45/50/55.

Although if that does happen I don't think they will share the same wing as you won't have enough range in a -7 or the -5 would do something crazy like 6,500NM. Just like in the Leeham article which seems to show the -5 with a wing significantly smaller.https://leehamnews.com/2021/02/03/final ... direction/

morrisond wrote:

Although if that does happen I don't think they will share the same wing as you won't have enough range in a -7 or the -5 would do something crazy like 6,500NM. Just like in the Leeham article which seems to show the -5 with a wing significantly smaller.

I would expect all three NMA to share the same wing, but I could see Boeing "clipping" NMA-5's wing like they originally intended to do with the 787-3. I could see that wing sized to 36m to fit in existing narrowbody (ICAO Code C) while the NMA-6 and NMA-7 could go up to 52m for ICAO Code D.

Revelation wrote:

No doubt managing such an endeavor is a huge challenge, but after the fact we have some pretty glaring problems to solve. Boeing admits MCAS put too much workload on the pilots and admits the decision to allow MCAS to operate with one active AoA sensor was made by one individual applying a non-documented industry rule of thumb. The 737 Chief Engineer admits he didn't know MCAS used only one AoA sensor and had multiple activation authority till he read about it in the media. None of their quality processes caught the flaws, mainly because their Safety Analysis was flawed and they found a way to categorize MCAS as not being a new function. The only good thing about the glaring nature of these problems is hopefully it will make them easier to fix.

As a former insider who worked many new airplane programs--but not the 737 Max--this explanation always seemed to be the scenario of how the MCAS architecture came to be. A very late change to the architecture with insufficient technical review before implementation. I don't want moderators to remove this question or divert the thread, however, I have not seen any published reports which state that one or a even a few individuals were responsible for approving the final MCAS system architecture, which relied upon a single AoA sensor. Is there a source or is this an inference?

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

A twin Isle CRJ 900

Pythagoras wrote:

Revelation wrote:

No doubt managing such an endeavor is a huge challenge, but after the fact we have some pretty glaring problems to solve. Boeing admits MCAS put too much workload on the pilots and admits the decision to allow MCAS to operate with one active AoA sensor was made by one individual applying a non-documented industry rule of thumb. The 737 Chief Engineer admits he didn't know MCAS used only one AoA sensor and had multiple activation authority till he read about it in the media. None of their quality processes caught the flaws, mainly because their Safety Analysis was flawed and they found a way to categorize MCAS as not being a new function. The only good thing about the glaring nature of these problems is hopefully it will make them easier to fix.

As a former insider who worked many new airplane programs--but not the 737 Max--this explanation always seemed to be the scenario of how the MCAS architecture came to be. A very late change to the architecture with insufficient technical review before implementation. I don't want moderators to remove this question or divert the thread, however, I have not seen any published reports which state that one or a even a few individuals were responsible for approving the final MCAS system architecture, which relied upon a single AoA sensor. Is there a source or is this an inference?

The closest statement I can find to what I suggest above is:

(Boeing CEO David Calhoun) said company and external investigations into the MAX crashes have “pointed to an assumption that was made with respect to pilot behavior and a set of failure analyses that were wrong.”

Boeing’s formal system safety analysis of the flight control software implicated in the crashes — the Maneuvering Characteristics Augmentation System (MCAS) — assumed the pilots would recognize what was wrong if it failed and would counter it manually within four seconds.

“It was a judgment everybody wishes they hadn’t made,” Calhoun said. He added that the crucial significance of that judgment should have been called out for MAX program leaders, “but that’s not what happened.”

Ref: https://www.seattletimes.com/business/b ... estore-it/

I think this covers the bulk of your question, no?

I can't find a quote to say it was just one person's decision on the four second rule, but I do recall reading that. Maybe my mind is playing tricks, or maybe my search karma isn't strong today. Let's go with the above for now. The four second judgment is the basis for allowing the single AoA sensor.

Part of me wishes I had made a notebook and printed out every article I've read on this subject and highlighted any/all key quotes and even did a cross-reference.

Maybe we'll have to wait for Dominick Gates to publish a book, I'm sure he could get a best seller out of it.

Stitch wrote:

morrisond wrote:

Although if that does happen I don't think they will share the same wing as you won't have enough range in a -7 or the -5 would do something crazy like 6,500NM. Just like in the Leeham article which seems to show the -5 with a wing significantly smaller.

I would expect all three NMA to share the same wing, but I could see Boeing "clipping" NMA-5's wing like they originally intended to do with the 787-3. I could see that wing sized to 36m to fit in existing narrowbody (ICAO Code C) while the NMA-6 and NMA-7 could go up to 52m for ICAO Code D.

That could work but that would be quite the clip. The 787-3 was only supposed to be an 8M clip to 52M from the 788/9's 60.1.

Actually thinking about it more I think it's more likely Boeing does a folding wing that fits in the Code C gate with a wingbox that is sized the same as an NSA wingbox (but strengthened obviously) and the NMA-5 is basically an NSA-ER with same nose and cross section.

Then the 6-7 use a new Wingbox with a wing that may go beyond 52m with folding tips. We may not say the 6 and 7 for quite some time though.

I think the new digital design tools are really going to change things up and allow changes in primary structures a lot easier than in the past. The lineup could look something like the following:

NSA-S - 40M 3,500 NM 36M Non-Folding Wing 2034 EIS
NSA-L - 45M 3,000 NM 36M Non-Folding Wing 2036 EIS
NMA-S(5) 45m 5,500 NM 36M When Folded Wing 2030 EIS
NMA -M (6) 50m 4,750NM 36M When Folded Wing 2032 EIS
NMA - L 55m 6,000NM 52M When Folded Wing (Arriving late 2030's)
NMA - XL 60M 5,250NM 52M When Folded Wing (Arriving late 2030's)

By the late 2030's an 789 should be capable of really silly ranges after being reengined but will be really useful for those who want to carry cargo. The NMA-L and XL will become the people movers.

Revelation wrote:

(Boeing CEO David Calhoun) said company and external investigations into the MAX crashes have “pointed to an assumption that was made with respect to pilot behavior and a set of failure analyses that were wrong.”

Boeing’s formal system safety analysis of the flight control software implicated in the crashes — the Maneuvering Characteristics Augmentation System (MCAS) — assumed the pilots would recognize what was wrong if it failed and would counter it manually within four seconds.

“It was a judgment everybody wishes they hadn’t made,” Calhoun said. He added that the crucial significance of that judgment should have been called out for MAX program leaders, “but that’s not what happened.”

Ref: https://www.seattletimes.com/business/b ... estore-it/

I think this covers the bulk of your question, no?

I can't find a quote to say it was just one person's decision on the four second rule, but I do recall reading that. Maybe my mind is playing tricks, or maybe my search karma isn't strong today. Let's go with the above for now. The four second judgment is the basis for allowing the single AoA sensor.

Part of me wishes I had made a notebook and printed out every article I've read on this subject and highlighted any/all key quotes and even did a cross-reference.

Maybe we'll have to wait for Dominick Gates to publish a book, I'm sure he could get a best seller out of it.

Dominic Gates' reporting is better than most, but as a reporter he doesn't have the technical background or industry experience to understand what is important to the story as compared to what is peripheral. It took a very long time for him to report that MCAS functionality was changed to a single-sensor during flight test. It is my perception that the real reason for expansion of MCAS into low speed regime has not been well reported. From my understanding of reading released internal Boeing emails, column forces were tapering off before buffet onset which is a non-certifiable condition. It really had nothing to do with common pilot type-rating between 737NG and 737Max. Furthermore, this is something that wind tunnel testing and analysis beforehand is not going to predict. Finding these things out is why one does flight test.

Thanks for the reply. Probably enough on this topic otherwise will be moved to another thread.

Pythagoras your statement is incorrect. The 737 MCAS functionality was dependent on a single sensor until the fix demanded by the FAA and other regulatory agencies. It was not changed to a single AOA sensor in flight test at Boeing like you stated. It should have been changed to dual AOA sensor information and comparison when the MCAS was added for the 737 MAX using angle of attack information to operate the MCAS. In the past it was not feeding systems that had a direct affect on the flight controls like MCAS as far as I understand. Sadly any one who has some experience with angle-of-attack sensors in their life should have realized that this was very bad engineering at best. As a pilot I have had angle of attack sensors malfunction during flight and kick in stick pushers on non-boeing aircraft before I worked in Boeing Flight Test. It is not fun to deal with as the stick pusher suddenly engaged with around 60 pounds nose down force at 250 knots airspeed in the Learjet I was flying. But at least these aircraft designs were from the early 1960s not the 2000s so engineers did not know better at the time I presume. I am sure Boeing flight controls engineering will have some explaining to do when the civil court cases start and there is the possibility that the criminal cases can be reopened in my estimation. That was left open in the agreement with the department of justice that Boeing agreed to.
Pythagoras it sounds like you need to improve your technical background and industry experience from what I tell!

I too think the single sensor "federated architecture" is an artifact of the NG and earlier models which was deemed acceptable because before MCAS it was not a part of systems needed to gain certification, and the "recover in four seconds" judgment served to avoid requiring redundancy.

I have to agree DG would need a skilled technical adviser or co-writer to make a book that us avgeeks would be happy with, but still think he could have a bestseller with or without mastery of all the technical details.

The single sensor was from both the classic and NG 737s where it was only tied to warning systems like the stick shaker and caused the Autopilot system to disconnect which forces the crew to manually fly the aircraft. I did final simulator evaluations on a number of 737 Classic simulators when I worked for the world's largest simulator manufacturer 20 years ago and from what I recall the main system triggered by the AOA sensors was the stick shaker on the side of the AOA sensor (Left and Right). Both stick shakers were independent from one another. The stick shaker only vibrates the control column and does not change the stick force, trim and/or change the pitch attitude of the aircraft. It is a distraction from other issues that is confusing at best. Unfortunately when more integrated systems like MCAS are added it adds the possibility of issues and makes the crew interpretation of what is going on very hard and very unlikely to happen within 4 seconds if at all when it malfunctions like happened with the MAX. It did not help that all references and training related to the MCAS were removed from the references and training that the flight crews receive. And it does not help that the Crew Training and experience of the crews involved was probably fairly marginal at best. Finally no ground and/or simulator training on MCAS was required before the accidents. AOA sensors can malfunction for quite a few real world issues like the sensor getting stuck due to ice buildup from pilots forgetting to turn on the anti-ice and/or from anti-ice system failures in icing conditions and at high altitudes, etc. and bird strikes on the sensor which will probably be an issue that happened in the Ethiopian 737 MAX aircraft accident when the final report is issued. But we will have to wait for the report to be issued. As has been stated before about many aircraft accidents causes are like the Swiss Cheese model where a number of issues like the holes in the cheese have to line up to cause the accident. This seems to have happened with the 737 MAX accidents.

Revelation wrote:

I too think the single sensor "federated architecture" is an artifact of the NG and earlier models which was deemed acceptable because before MCAS it was not a part of systems needed to gain certification, and the "recover in four seconds" judgment served to avoid requiring redundancy.

I have to agree DG would need a skilled technical adviser or co-writer to make a book that us avgeeks would be happy with, but still think he could have a bestseller with or without mastery of all the technical details.

It appears that I need to clarify my prior remarks. The initial configuration of MCAS up until flight test was configured to use inputs from a G-sensor and angle-of-attack--two dissimilar sensors--to initiate the functionality. This was to address characteristics in a high-speed wind-up turn which could be reliably simulated from wind tunnel data. The flight test change in the low speed flight envelope removed the second G-sensor, which made the system more susceptible to uncommanded activation. The change in flight test was from two sensors to one sensor exclusively.

OK but Flight Test does not change the sensors used and/or modify/change the system. Engineering reviews the data obtained from Flight Test and uses Flight Test data and recommendations to modify and possibly redesign/modify the system to meet the requested changes that are discovered during flight testing. They still have to ensure that the system is not dependent on a single sensor as happened with the MAX. And they should have done a new safety study allowing for the greater dependence on the AOA sensor and its potential malfunctions and/or failures. They continued to assume that the AOA sensor would never fail and have any affects on the aircraft (i.e. it was perfect and even if it failed/malfunctioned it would have minimal effects on the aircraft).
It is not clear whether the MCAS was even required to increase the stick force gradient on approach to stall in the case of the MAX. Transport Canada has for example questioned why the MCAS was required in the first place other then to avoid simulator training in a 737 MAX full flight simulator.
Thank god, I was not involved with the 737 MAX fortunately/unfortunately depending on how you look at it.

morrisond wrote:

Stitch wrote:

morrisond wrote:

Although if that does happen I don't think they will share the same wing as you won't have enough range in a -7 or the -5 would do something crazy like 6,500NM. Just like in the Leeham article which seems to show the -5 with a wing significantly smaller.

I would expect all three NMA to share the same wing, but I could see Boeing "clipping" NMA-5's wing like they originally intended to do with the 787-3. I could see that wing sized to 36m to fit in existing narrowbody (ICAO Code C) while the NMA-6 and NMA-7 could go up to 52m for ICAO Code D.

That could work but that would be quite the clip. The 787-3 was only supposed to be an 8M clip to 52M from the 788/9's 60.1.

Actually thinking about it more I think it's more likely Boeing does a folding wing that fits in the Code C gate with a wingbox that is sized the same as an NSA wingbox (but strengthened obviously) and the NMA-5 is basically an NSA-ER with same nose and cross section.

Then the 6-7 use a new Wingbox with a wing that may go beyond 52m with folding tips. We may not say the 6 and 7 for quite some time though.

I think the new digital design tools are really going to change things up and allow changes in primary structures a lot easier than in the past. The lineup could look something like the following:

NSA-S - 40M 3,500 NM 36M Non-Folding Wing 2034 EIS
NSA-L - 45M 3,000 NM 36M Non-Folding Wing 2036 EIS
NMA-S(5) 45m 5,500 NM 36M When Folded Wing 2030 EIS
NMA -M (6) 50m 4,750NM 36M When Folded Wing 2032 EIS
NMA - L 55m 6,000NM 52M When Folded Wing (Arriving late 2030's)
NMA - XL 60M 5,250NM 52M When Folded Wing (Arriving late 2030's)

By the late 2030's an 789 should be capable of really silly ranges after being reengined but will be really useful for those who want to carry cargo. The NMA-L and XL will become the people movers.

With a digital all CFRP design you do not need to share a structure, each variant gets their own perfectly optimized version. Think it of it as 3 different aircraft that can be made using the same tools and on the same production line.

The 757/767 program was a great success. Just repeat it with new designs. A narrowbody to compete against the A321 and a widebody to replace 763/764/332.

DartHerald wrote:

Opus99 wrote:

https://leehamnews.com/2021/04/08/analyzing-the-trades-between-a-single-and-twin-aisle-nma/

Leeham talks about how they think NMA must be twin aisle. 3 family member.

With one member being the size of the 321.

I really wonder what a twin aisle that short will look like.

An A310? or 767-200?

B767-200 with 28" seat pitch in 7-abreast configuration could carry around 280 pax. A321neo with 28" seat pitch in 6-abreast configuration could carry maximum of 240 pax.

So there is around 40 pax differences between the 2. In order for the twin-aisle NMA to carry 240-250 passengers, the NMA would need to be around 45m in length.

So shorter than A310.

TTailedTiger wrote:

The 757/767 program was a great success. Just repeat it with new designs. A narrowbody to compete against the A321 and a widebody to replace 763/764/332.

It won't work since Airlines wants to streamline their operation these days. B787-8 could do B767-400ER and A330-200 more efficiently. And A321XLR could do B757-200 more efficiently.

Many airlines that use B757-200 already have A321 on their fleet and some XLR on order.

ewt340 wrote:

TTailedTiger wrote:

The 757/767 program was a great success. Just repeat it with new designs. A narrowbody to compete against the A321 and a widebody to replace 763/764/332.

It won't work since Airlines wants to streamline their operation these days. B787-8 could do B767-400ER and A330-200 more efficiently. And A321XLR could do B757-200 more efficiently.

Many airlines that use B757-200 already have A321 on their fleet and some XLR on order.

So why wouldn't a new 752 size plane be more efficient than a late 80's design A321?

Pythagoras, CanukinUSA, thank you for your educated views, opinions above.

Back to topic, I think many of the NMA specifications, outlooks drift on one major assumption:
The 737 MAX will be just fine against A320 / A220 families this decade.

There are signs that's not a realistic assumption. Market share / backlog, order value of the 737 have been dropping.
We can play around with in service numbers, time windows, but I think the writing is on the wall on the good old 737.
It was visible already before the crashes / Covid-19.


https://leehamnews.com/2020/10/27/with-max-nearing-recertification-boeing-has-bigger-problem/

The latest A320 vs 737 '19-'21 delivery figures / delta's are shocking. And it's not like WB's are saving Boeing.
Boeing needs to cover it's bases first and fix it's 150-220 seats up to 3000NM segment later this decade

That is the bread & butter of the global aviation market and also for Boeing. Not offering a viable A220/A320 competitor, alternative, MAX conversion option could drive Boeing South, like never before.

Meanwhile, Airbus keeps investing in NB portfolio expansion and product improvements, driven by market demand. https://groups.google.com/group/aviatio ... 0.1&view=1

As an example, I saw this A320 improvement project this week. https://www.flightglobal.com/air-transp ... 03.article A significant A320 family modification. Not required by authorities, costing a lot of time/ certification / money, reducing standardisation, reducing free cash flow. But a good long term family improvement. A very different development approach compared to policies at their biggest competitor.

I think Boeing's next airplane will be a shrunken, single aisle NMA, a 737 replacing NB. Single aisle because it seems a 225 seat, 4000NM dual aisle aircraft will always be 6-8t heavier than a 225 seat, 4000NM single aisle aircraft. There is no engineering magic that works for twin aisles only. Direct operating costs and OEW are closely related.

Shelve NMA, do a NB 10% better"" than the NEO's asap.

TTailedTiger wrote:

So why wouldn't a new 752 size plane be more efficient than a late 80's design A321?

It would be, just like a 2021 A321neo/XLR is.

keesje wrote:

Pythagoras, CanukinUSA, thank you for your educated views, opinions above.

Back to topic, I think many of the NMA specifications, outlooks drift on one major assumption:
The 737 MAX will be just fine against A320 / A220 families this decade.

There are signs that's not a realistic assumption. Market share / backlog, order value of the 737 have been dropping.
We can play around with in service numbers, time windows, but I think the writing is on the wall on the good old 737.
It was visible already before the crashes / Covid-19.


https://leehamnews.com/2020/10/27/with-max-nearing-recertification-boeing-has-bigger-problem/

The latest A320 vs 737 '19-'21 delivery figures / delta's are shocking. And it's not like WB's are saving Boeing.
Boeing needs to cover it's bases first and fix it's 150-220 seats up to 3000NM segment later this decade

That is the bread & butter of the global aviation market and also for Boeing. Not offering a viable A220/A320 competitor, alternative, MAX conversion option could drive Boeing South, like never before.

Meanwhile, Airbus keeps investing in NB portfolio expansion and product improvements, driven by market demand. https://groups.google.com/group/aviatio ... 0.1&view=1

As an example, I saw this A320 improvement project this week. https://www.flightglobal.com/air-transp ... 03.article A significant A320 family modification. Not required by authorities, costing a lot of time/ certification / money, reducing standardisation, reducing free cash flow. But a good long term family improvement. A very different development approach compared to policies at their biggest competitor.

I think Boeing's next airplane will be a shrunken, single aisle NMA, a 737 replacing NB. Single aisle because it seems a 225 seat, 4000NM dual aisle aircraft will always be 6-8t heavier than a 225 seat, 4000NM single aisle aircraft. There is no engineering magic that works for twin aisles only. Direct operating costs and OEW are closely related.

Shelve NMA, do a NB 10% better than the NEO's asap.

Or they can just throw money in the dustbin. I don’t understand. How many times will people say the tech is not ready. Who wants to spend that for 10% you launch in 2030. Then 2032 Airbus will launch something that will cut your jets efficiency by what 15%? Because they will take advantage of the tech available then. This year MAX has outsold 320neo family since it came back. MAX is still relevant and should not be discounted. It is very competitive in the ranges it can do comfortably which is majority of the 320 family. Boeing must do something now in that 200-220 seat market. If a widebody does it fine, if a narrow body does it fine. The whole idea is the seat count and the most efficient way to fly in that seat count. At the end of the day it’s the engineers that know. If they go ahead with this hybrid fuselage and with the lengths we are talking of. If the MAX10 can compete on smaller routes then I think it’s fine. But customers need real life data which the neo has in excess. Max10 does not. Boeing’s analysis makes sense if you’re looking for range from mid market. NMA will be better for you. If you’re looking for people mover but not range they’ll offer you Max10. It’s atracking the 321neo from below and above. It could work for them but they’ll just have to be very aggressive

keesje wrote:

Pythagoras, CanukinUSA, thank you for your educated views, opinions above.

Back to topic, I think many of the NMA specifications, outlooks drift on one major assumption:
The 737 MAX will be just fine against A320 / A220 families this decade.

There are signs that's not a realistic assumption. Market share / backlog, order value of the 737 have been dropping.
We can play around with in service numbers, time windows, but I think the writing is on the wall on the good old 737.
It was visible already before the crashes / Covid-19.


https://leehamnews.com/2020/10/27/with-max-nearing-recertification-boeing-has-bigger-problem/

The latest A320 vs 737 '19-'21 delivery figures / delta's are shocking. And it's not like WB's are saving Boeing.
Boeing needs to cover it's bases first and fix it's 150-220 seats up to 3000NM segment later this decade

That is the bread & butter of the global aviation market and also for Boeing. Not offering a viable A220/A320 competitor, alternative, MAX conversion option could drive Boeing South, like never before.

Meanwhile, Airbus keeps investing in NB portfolio expansion and product improvements, driven by market demand. https://groups.google.com/group/aviatio ... 0.1&view=1

As an example, I saw this A320 improvement project this week. https://www.flightglobal.com/air-transp ... 03.article A significant A320 family modification. Not required by authorities, costing a lot of time/ certification / money, reducing standardisation, reducing free cash flow. But a good long term family improvement. A very different development approach compared to policies at their biggest competitor.

I think Boeing's next airplane will be a shrunken, single aisle NMA, a 737 replacing NB. Single aisle because it seems a 225 seat, 4000NM dual aisle aircraft will always be 6-8t heavier than a 225 seat, 4000NM single aisle aircraft. There is no engineering magic that works for twin aisles only. Direct operating costs and OEW are closely related.

Shelve NMA, do a NB 10% better than the NEO's asap.

Wow - of course MAX deliveries from 19-21 were substantially worse and probably will be for sometime. Did you miss the MAX delivery shutdown and airlines not wanting to take new frames due to Covid?

Please detail for us why a tight light 2 aisle fuselage that has less skin area and less internal volume than a comparable capacity 1 aisle will be 6-8T heavier when a bare entire A320 fuselage only weighs about 5T.

Yes - the the 50% approximately by length of the fuselage cross sections that are not the nose or above the wingbox or the tail will be a bunch heavier per meter but then of course there will be about 20-25% less of those meters by length for equivalent capacity for something that is essentially the same height but with a 15" bulge on each side.

Theoretically assuming you have enough clearance for the fans the 2 aisle could possibly use shorter gear as well to obtain the same rotation angle.

keesje wrote:

I think Boeing's next airplane will be a shrunken, single aisle NMA, a 737 replacing NB. Single aisle because it seems a 225 seat, 4000NM dual aisle aircraft will always be 6-8t heavier than a 225 seat, 4000NM single aisle aircraft. There is no engineering magic that works for twin aisles only. Direct operating costs and OEW are closely related.

I’m not so sure 4000nm range target is the right spot. The average A320 and 737 flight is just under 1000nm. A plane capable of flying 4000nm will be carrying a lot of excess structure on more typical 400-1000nm flights.

If you look at the 50 busiest routes in the world, only one is longer than 1200nm and that is New York - Los Angeles. The average length of the top 10 busiest routes in the world is only 500nm!

https://en.m.wikipedia.org/wiki/List_of ... air_routes

I'd be interested to know how Boeing is supposed to make an A320neo clone that is 10% better"" using the same materials and engines that the A320neo does.

The MAX wing is already better"" than the A320neo wing, but I'm not sure how they make it so much better"" that it reduces direct operating costs by 10% over an A320neo unless they just go with a ridiculous span length that would make it unworkable at a significant number of the airports, much less gates, that the airframes operate out of.

Pythagoras wrote:

It appears that I need to clarify my prior remarks. The initial configuration of MCAS up until flight test was configured to use inputs from a G-sensor and angle-of-attack--two dissimilar sensors--to initiate the functionality. This was to address characteristics in a high-speed wind-up turn which could be reliably simulated from wind tunnel data. The flight test change in the low speed flight envelope removed the second G-sensor, which made the system more susceptible to uncommanded activation. The change in flight test was from two sensors to one sensor exclusively.

Thank you for the clarification, it makes sense now.

CanukinUSA wrote:

OK but Flight Test does not change the sensors used and/or modify/change the system. Engineering reviews the data obtained from Flight Test and uses Flight Test data and recommendations to modify and possibly redesign/modify the system to meet the requested changes that are discovered during flight testing. They still have to ensure that the system is not dependent on a single sensor as happened with the MAX. And they should have done a new safety study allowing for the greater dependence on the AOA sensor and its potential malfunctions and/or failures. They continued to assume that the AOA sensor would never fail and have any affects on the aircraft (i.e. it was perfect and even if it failed/malfunctioned it would have minimal effects on the aircraft).

Thank you also for clarification. "During flight test" which is the original quote is different than "by flight test".

CanukinUSA wrote:

It is not clear whether the MCAS was even required to increase the stick force gradient on approach to stall in the case of the MAX. Transport Canada has for example questioned why the MCAS was required in the first place other then to avoid simulator training in a 737 MAX full flight simulator.

I think TC was saying MAX did not meet the stick force gradient requirements, but the illness (light stick near the edge of the flight envelope) was worse than the cure (MCAS).

CanukinUSA wrote:

Thank god, I was not involved with the 737 MAX fortunately/unfortunately depending on how you look at it.

It might be interesting to point out the guy who was the MAX chief engineer when most of the critical decisions were made (and who signed off on the certification documents) is now 777X chief engineer. One insider suggested the outcome is that he doesn't want to be accused of not knowing things and delegating too much so he's now become a micro-manager. Seems they really could use some checks and balances in their system.

Stitch wrote:

I'd be interested to know how Boeing is supposed to make an A320neo clone that is 10% better"" using the same materials and engines that the A320neo does.

The MAX wing is already better"" than the A320neo wing, but I'm not sure how they make it so much better"" that it reduces direct operating costs by 10% over an A320neo unless they just go with a ridiculous span length that would make it unworkable at a significant number of the airports, much less gates, that the airframes operate out of.

Weatherwatcher1 wrote:

keesje wrote:

I think Boeing's next airplane will be a shrunken, single aisle NMA, a 737 replacing NB. Single aisle because it seems a 225 seat, 4000NM dual aisle aircraft will always be 6-8t heavier than a 225 seat, 4000NM single aisle aircraft. There is no engineering magic that works for twin aisles only. Direct operating costs and OEW are closely related.

I’m not so sure 4000nm range target is the right spot. The average A320 and 737 flight is just under 1000nm. A plane capable of flying 4000nm will be carrying a lot of excess structure on more typical 400-1000nm flights.

If you look at the 50 busiest routes in the world, only one is longer than 1200nm and that is New York - Los Angeles. The average length of the top 10 busiest routes in the world is only 500nm!

https://en.m.wikipedia.org/wiki/List_of ... air_routes

Weatherwatcher, you are 100% correct referencing average stage length. Europe, US E & W coasts, India, China East coast is where most people live & fly. 1000NM indeed covers a majority of all flights. Maybe there Boeing can challenge Airbus. An all CFRP lean aircraft with a range up to 2000NM, 1:15 BPR geared, CMC engines, flying a little slower, maybe 5% lower weights. 10% less fuel per passenger / kilometer seems doable. That would fail to address A321/322 enhanced NEO versions from 2027 though.

It seems hard for Boeing (or anyone) to address both the A220 and A322 markets, 120-250 seats, with a single base design. Ignoring reality and going 220-280 seats up to 5000NM NMA seems an even more uncertain trajectory.


source: keesje.

morrisond wrote:

Wow - of course MAX deliveries from 19-21 were substantially worse and probably will be for sometime. Did you miss the MAX delivery shutdown and airlines not wanting to take new frames due to Covid?

Also must have missed that WN did not buy any A220s after years of beating that drum. Now we're back to "737 is doomed" right after MAX7 wins the biggest order available in the A220/A319/MAX7 size category for this generation of aircraft production. 200 MAX7 on firm order at WN is quite an achievement for a model some doubted would ever get built.

Now we get a FUD pie chart based on cherry picked data. The remedy? Abandon the model that you can produce, tell the customers that the models they just ordered are soon to be replaced so value will plummet, tell the engine makers and the rest of the supply chain their investment in MAX is about to be zero'd out and they need to start raising capital for a replacement during the worst aviation crisis ever, because of a market share pie chart.

We've heard it all before, and it makes less sense now that MAX has had a successful RTS without the panic that was often predicted and UA, AS, FR and WN have made large new commitments to the aircraft, 737-8200 is certified, MAX7 will be delivered this year and MAX10 will be out in 2023.

keesje wrote:

Ignoring reality and going 220-280 seats up to 5000NM NMA seems an even more uncertain trajectory.

It's a market that is currently being addressed inefficiently with existing narrowbody and widebody designs and one that Airbus cannot as-effectively respond to without doing their own clean-sheet design.

I simply recommend looking at what the engine OEMs and their large suppliers are saying, to get a reality check on future airliners. Nearly all plans involve evolutions of existing technology, either upgrading the core for the GTF or adding the gear to the non GTF engines. After that it will be compatibility with alternative fuels after 2035 and development from there. There is a bout 10% in efficiency to be had with new engines after 2030 compared to what is put on the wings today or was put on the wings in the last 5 years. But it won´t be 10% compared to what is put on the wings in 2030, it will be 5-6% at best.

Stitch wrote:

keesje wrote:

Ignoring reality and going 220-280 seats up to 5000NM NMA seems an even more uncertain trajectory.

It's a market that is currently being addressed inefficiently with existing narrowbody and widebody designs and one that Airbus cannot as-effectively respond to without doing their own clean-sheet design.

I really wonder what segment is left for an NMA when Airbus has taken out the bottom with cheap A321 variants and 787s / A330s do most 4000-4500NM flights at MTOW today with 250-300 passenger in 3-4 classes and 10-20t of revenue cargo. I really wonder, and so do GE and RR. And the airlines apparently.

https://www.ainonline.com/aviation-news ... t-aircraft
https://www.ainonline.com/aviation-news ... ompetition

Boeing needs to face the future, find strong partner(s) and move ahead. No need to put defibrillators on the MOM/NMA.
Boeings FSA ASAP seems a better way ahead IMO. https://theaircurrent.com/aircraft-deve ... -airplane/

I don't think Boeing can't survive too many WN, FR "wins" https://leehamnews.com/2021/04/05/ponti ... us-to-bid/, ($23-30mln ) and they need a real competitive offer also in to 130-150 seat segment. https://www.aerotime.aero/upload/files/ ... _price.jpg

If I was Boeing's CEO (unfortunately I'm not earning $21mln for 2020) I wouldn't burn myself again trying to fight of A321 / A322. That probably won't bring in a lot of dollar margin anytime soon. After 6 years of trying to market the NMA, Calhouns blank sheet approach, I wouldn't be surprised if NMA has become a decoy for a more ambitious, attractive NB program that could stear Boeing back on track for restoring parity in it's biggest market segment.

keesje wrote:

If I was Boeing's CEO (unfortunately I'm not earning $21mln for 2020) I wouldn't burn myself again trying to fight of A321 / A322. That probably won't bring in a lot of dollar margin anytime soon. After 6 years of trying to market the NMA, Calhouns blank sheet approach, I wouldn't be surprised if NMA has become a decoy for a more ambitious, attractive NB program that could stear Boeing back on track for restoring parity in it's biggest market segment.

You aren't a CEO fortunately. Because this is flat out wrong.

Even if you make 1 dollar per aircraft, selling it makes sense. Your sunk costs are what they are, as long as you are making an operational profit on each subsequent build and able to keep competitor prices down, you're still coming out ahead.

What's your plan? Just stop selling a jet you've spent money developing and will be profitable on a per aircraft production basis in the future?