konrad
Topic Author
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Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 6:11 pm

I hope the moderators will allow this silly question in the subject line. This is for the sake of asking more informed members of this forum about their technical expertise. What are the modification of B737MAX vs B737NG apart from the different engines and, obviously, attachment pads and interfaces with the wings? Would it be possible at all to modify parts of the wing and attach 737NG engines to a 737MAX airframe? This has nothing to do with why would one do such a thing, just speculating.
 
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adamblang
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 6:21 pm

I Googled "what are the differences between the 737NG and 737MAX" and got this:

http://www.b737.org.uk/737maxdiffs.htm#diffs
146 319 320 321 332 333 343 717 734 735 73G 738 739 744 752 753 763 764 772 773 789 AR1 AT4 CNA CR2 CR7 DC9 ER3 ERD ER4 E70 E75 E90
 
BOSAero
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 6:24 pm

Aside the 737 name and look, the MAX is a completely different iteration of the model. I’m sure If someone wanted to do this, the old CFM engine from the NG would not fit on the pylon. Or if you would like to change to the old pylon from the NG, it would not fit on the MAX wing..... so on and so forth....

This same scenario goes for pretty much everything else on the airplane. (Avionics, pneumatics, electrical systems, hydraulics, etc).

What you’re asking is to reengineer the MAX back to an NG. Right? Makes no sense.
 
Sooner787
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 6:55 pm

Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more
 
anshabhi
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:06 pm

Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

For the coming days, Boeing will only be able to build NG
 
SNN99
Posts: 18
Joined: Wed Jan 23, 2019 8:18 pm

Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:08 pm

anshabhi wrote:
Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

For the coming days, Boeing will only be able to build NG

Says who, they have said themselves they will continue to build through the grounding.
 
Sooner787
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:09 pm

anshabhi wrote:
Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

For the coming days, Boeing will only be able to build NG


Actually..... they're still building Max's , they just stopped deliveries.

They'll have quite a backlog of frames to deal with once deliveries resume
 
Arion640
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:25 pm

Why would airlines want to do that? The plane will be flying again in a few months.
223 319 320 321 333 346 359 388 733 73G 738 744 752 753 763 772 77E 773 77W 788 789 E145 E175 E195 RJ85 F70 DH8C DH8D AT75

Brexit - It’s time for global Britain.
 
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Finn350
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:26 pm

konrad wrote:
I hope the moderators will allow this silly question in the subject line. This is for the sake of asking more informed members of this forum about their technical expertise. What are the modification of B737MAX vs B737NG apart from the different engines and, obviously, attachment pads and interfaces with the wings? Would it be possible at all to modify parts of the wing and attach 737NG engines to a 737MAX airframe? This has nothing to do with why would one do such a thing, just speculating.


Of course it would be possible although it would be so expensive that there is no point in it.
 
Boof02671
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:30 pm

anshabhi wrote:
Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

For the coming days, Boeing will only be able to build NG

Not true, they are still building thee MAX over 50 a month.
 
GalaxyFlyer
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:30 pm

Sure, take it to hot rod shop that specializes in conversions, they’ll saw it up, hang the old engines on it with an adapter plate, you’re good to go. My God, where do these ideas come from?



Gf
 
anshabhi
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:31 pm

Boof02671 wrote:
anshabhi wrote:
Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

For the coming days, Boeing will only be able to build NG

Not true, they are still building thee MAX over 50 a month.

Isn't is stupid to make an airframe which is globally grounded, without any modifications at all?
 
D L X
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 7:37 pm

anshabhi wrote:
Boof02671 wrote:
anshabhi wrote:
For the coming days, Boeing will only be able to build NG

Not true, they are still building thee MAX over 50 a month.

Isn't is stupid to make an airframe which is globally grounded, without any modifications at all?

The time it takes to build an airframe from scratch is much longer than the grounding will be.

Especially if the fix is in software, it is likely that the fixes will be inserted into the workflow at the appropriate point when they are available, and any undelivered ships would be modified just like the ones currently in airlines' hands.

Also, shutting down an assembly line is expensive. Restarting it is even more expensive. Entire supply chains are affected. If you imagine a simpler product, say a house, halting construction on the house means stopping the shipment of parts - windows, doors, floorboards, etc. That means that the guy that makes the windows, doors, or floorboards, has to stop production too. THAT means the guy that cuts the wood or makes the glass panes has to stop production too. Halting construction has massive downstream effects that if can be avoided, should be.

Hell, in the auto industry, it's a BFD when they shut down a plant for a few hours, it does so much damage to the supply chain.
 
SNN99
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 8:00 pm

Boeing has said the software update will be out in 10 days
 
Gazdon121
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 9:01 pm

While they continue to build through the grounding, does Renton have the space to store these frames
 
jfk777
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 9:27 pm

If it becomes a "Renton no space" problem Boeing can fly the MAx to other nearby airports. At some point Boeing is going to have test and re certify whatever the "Fix" is.
 
Campo
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Joined: Mon Mar 04, 2019 3:30 am

Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 10:13 pm

How can they fly them when they are grounded?
 
Boof02671
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 10:29 pm

They are allowed test flights and maintenance ferry flights.
 
Airlines0613
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Re: Is it possible to downgrade B737MAX to 737NG?

Fri Mar 15, 2019 10:31 pm

Campo wrote:
How can they fly them when they are grounded?

Boeing can obtain permits from the FAA, which most likely will be granted.
 
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precure787
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Re: Is it possible to downgrade B737MAX to 737NG?

Sat Mar 16, 2019 4:48 am

In terms of modifications, no. In terms of exchanging orders, yes.
The only 737NG variants that are still in production are the -800 and the -900ER series.
Edward Zen/Precure 787
 
Heinkel
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 10:29 am

D L X wrote:
Especially if the fix is in software, it is likely that the fixes will be inserted into the workflow at the appropriate point when they are available, and any undelivered ships would be modified just like the ones currently in airlines' hands.


This shows the problem with the people of the IPhone- and TESLA-generation; They think, everything can be fixed with a simple software update/upgrade.

In this case, may be it can, may be it can't. Be sure, that there are many high level meetings behind closed doors at the moment, where Boeing mangagers discuss, what to do with the MAX production.

The MAXes roll out from the assembly line in much higher numbers than the 787s, when they were grounded. So Boeing can't go on with a 50 per month production for a year or so, when it is not clear, how the solution looks like. Best case: A software update fixes the problem. Worst case: 737MAX needs a complete new type approval and grandfathering is denied.

Interesting times ahead.
 
stratclub
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 11:12 am

anshabhi wrote:
Boof02671 wrote:
anshabhi wrote:
For the coming days, Boeing will only be able to build NG

Not true, they are still building thee MAX over 50 a month.

Isn't is stupid to make an airframe which is globally grounded, without any modifications at all?

Safety, safety safety. Even with existing designs issues do pop up and if these issues have a negative effect on safety, you ground all aircraft with that safety issue. Stupid? No. You can not plan for a problem that you don't know about yet.

I would imagine that Boeing has not stopped production on the MAX. Whether Boeing could fly B1 (first flight) over to the delivery center at BFI would depend on the FAA granting a special permit with appropriate restrictions. Boeing may well be doing validation flights with FAA approved restrictions. They just can't get validation for the airworthiness certificate until the current problems are fixed which would mean no deliveries would be allowed.
 
stratclub
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 11:22 am

Sooner787 wrote:
Best way to do that is convert your new Max order to an 737NG order, assuming Boeing would be open to building a few more

Completely bad idea. The lack of parts in the NG supply chain would stop production dead in it's tracks.
 
SNN99
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 12:24 pm

precure787 wrote:
In terms of exchanging orders, yes.
The only 737NG variants that are still in production are the -800 and the -900ER series.

Wrong! NG production finishes on May 3rd
 
D L X
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 12:56 pm

Heinkel wrote:
D L X wrote:
Especially if the fix is in software, it is likely that the fixes will be inserted into the workflow at the appropriate point when they are available, and any undelivered ships would be modified just like the ones currently in airlines' hands.


This shows the problem with the people of the IPhone- and TESLA-generation; They think, everything can be fixed with a simple software update/upgrade.

In this case, may be it can, may be it can't. Be sure, that there are many high level meetings behind closed doors at the moment, where Boeing mangagers discuss, what to do with the MAX production.

The MAXes roll out from the assembly line in much higher numbers than the 787s, when they were grounded. So Boeing can't go on with a 50 per month production for a year or so, when it is not clear, how the solution looks like. Best case: A software update fixes the problem. Worst case: 737MAX needs a complete new type approval and grandfathering is denied.

Interesting times ahead.

I’m not of the iPhone/Tesla generation. I’m a computer engineer and lawyer from the 90s, before Tesla and iPhone existed. When you assume...

I did not say everything can be fixed with software, but as has been reported widely, Boeing is attempting to fix this with a software update to the MCAS system. (Note the big fat “if” in there.) So, what is untrue with what I just described?

Also, who here actually thinks it will be a year before MAX flies again? If it does take a protracted amount of time, yes, you will see a halt or slowdown in production. We ain’t there yet.

Now get off my lawn. :p
 
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Stitch
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 3:44 pm

SNN99 wrote:
NG production finishes on May 3rd


Commercial NG production may be scheduled to end then, but there will still be military 737-800A frames produced for the P-8 program.
 
namezero111111
Posts: 116
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 4:23 pm

konrad wrote:
Would it be possible at all to modify parts of the wing and attach 737NG engines to a 737MAX airframe?


Hehe.. yes, sure, you can start with just the data plate.

Whether it's economically viable is another question :}
 
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precure787
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Re: Is it possible to downgrade B737MAX to 737NG?

Sun Mar 17, 2019 9:46 pm

SNN99 wrote:
Wrong! NG production finishes on May 3rd


The production usually finishes when there's no more unfilled orders. You can't necessarily or precisely predict when the production would be finished with no outstanding orders. The 747-8, for example, would've ended production no later than 2020, but thanks to UPS doubling their 747-8F orders, the very last 747 would've rolled off the production line at around 2020. Airbus' quadjets, on the other hand, had to end the production earlier than they had expected, due to lack of further orders. Therefore, once the last order is filled with no new orders, it's done.
Edward Zen/Precure 787

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