-400F 635k MZFW no longer available?

[Captain Kevin 586]

9 hours ago, calzonister said:

Does that make sense?

Not really.

9 hours ago, calzonister said:

FYI, you do have access to the FCOM, thanks to PMDG 🙂 \Prepar3D v4\PMDG\PMDG 747 QOTS II\Flight Manuals

Yes, I'm aware of that. However, I'm not sure where you're seeing the various weight options. I'm only seeing the weight limitations for each airplane.

[scandinavian13 5,192]

Gents,

First, MTOW is pay-to-play, so whatever the operator pays for is what they get to use. There is a max certified weight by the regulatory authority, but any variation under that is simple a paper chase, and explains the different values.

If the assertion is that we provided a method by which someone could alter cfg files, I'm inclined to disagree. Again: we make it a point to either do the work for you, or provide alternative config files (like the alternative panel.cfg files) so that people cannot go digging into things and creating hassles for support because they changed the wrong value such that a 744 turns into an Extra 300.

[kevinh 409]

5 hours ago, scandinavian13 said:

Gents,

First, MTOW is pay-to-play, so whatever the operator pays for is what they get to use. There is a max certified weight by the regulatory authority, but any variation under that is simple a paper chase, and explains the different values.

If the assertion is that we provided a method by which someone could alter cfg files, I'm inclined to disagree. Again: we make it a point to either do the work for you, or provide alternative config files (like the alternative panel.cfg files) so that people cannot go digging into things and creating hassles for support because they changed the wrong value such that a 744 turns into an Extra 300.

That doesn't fully answer the question asked in the OP. The MZFW of the PMDG -400F used to be the higher figure (635,000 lb). Now it is 610,000 lb. I had setup the weights of the PMDG -400F in TOPCAT so everything matched properly. My TOPCAT setting hasn't changed so I have no doubt the higher MZFW figure was in the standard configuration previously (there was no option). It appears something has changed, but it isn't mentioned in the change list. Can you confirm this was intended and why it was done?

Edited January 16, 2019 by kevinh

[scandinavian13 5,192]

16 minutes ago, kevinh said:

That doesn't fully answer the question asked in the OP. The MZFW of the PMDG -400F used to be the higher figure (635,000 lb). Now its reduced, and is the same as the-400ERF. I had setup the weights of the PMDG -400F in TOPCAT so everything matched properly. My TOPCAT setting hasn't changed so I have no doubt the higher MZFW figure was in the standard configuration previously (there was no option).

That wasn't the aim of my post. I'd already answered the OP's question, and then - as has been happening a lot more, recently - people took a sharp left turn into Tangentland, and I wanted to cut the side chatter off because people were getting animated with each other in the face of the actuality of the situation by citing random conflicting sources that are going to naturally be in conflict as a matter of fact. I stated the fact because I got tired of watching the quarrel over inane details that don't help the original discussion.

So...I'll go back (again - this is the third time, for the record) :

5 hours ago, scandinavian13 said:

If the assertion is that we provided a method by which someone could alter cfg files, I'm inclined to disagree. Again: we make it a point to either do the work for you, or provide alternative config files (like the alternative panel.cfg files) so that people cannot go digging into things and creating hassles for support because they changed the wrong value such that a 744 turns into an Extra 300.

 

[kevinh 409]

19 minutes ago, scandinavian13 said:

That wasn't the aim of my post. I'd already answered the OP's question, and then - as has been happening a lot more, recently - people took a sharp left turn into Tangentland, and I wanted to cut the side chatter off because people were getting animated with each other in the face of the actuality of the situation by citing random conflicting sources that are going to naturally be in conflict as a matter of fact. I stated the fact because I got tired of watching the quarrel over inane details that don't help the original discussion.

So...I'll go back (again - this is the third time, for the record) :

 

Your answer to the OP was that there was no MZFW option available in the sim (which was and is true) but that didn't address his observation that he used to be able to use a ZFW of 635,000 lb, now the maximum is 610,000 lb.

Your latest reply doesn't answer the question I asked, has something changed that wasn't in the changelog? You just repeated the warning not to edit aircraft.cfg. I can only assume you don't realise this has changed either.

Edit: I see the MTOW remains as 850,000 lb (as per the higher MZFW option). If MZFW is 610,000 lb MTOW should be 875,000 lb.

Edited January 16, 2019 by kevinh

[sosuflyer 30]

Yes, I was not talking about editing. CFG files, I was just wondering why the Max zero fuel weight option had been changed from 635 to 610.  That's all.  Would like to see it changed back though.  

[PinkPony 171]

10 hours ago, Captain Kevin said:

Not really.

Yes, I'm aware of that. However, I'm not sure where you're seeing the various weight options. I'm only seeing the weight limitations for each airplane.

I hope the Boeing document I have linked below, helps you understand the relationship between either using the 635k MZFW or 875k MTOW. Loading the aircraft up to both limits simultaneously is prohibited due to structural limitations. 

https://m.imgur.com/a/QDgWtFn

 

8 hours ago, scandinavian13 said:

Gents,

First, MTOW is pay-to-play, so whatever the operator pays for is what they get to use. There is a max certified weight by the regulatory authority, but any variation under that is simple a paper chase, and explains the different values.

If the assertion is that we provided a method by which someone could alter cfg files, I'm inclined to disagree. Again: we make it a point to either do the work for you, or provide alternative config files (like the alternative panel.cfg files) so that people cannot go digging into things and creating hassles for support because they changed the wrong value such that a 744 turns into an Extra 300.

Hi Kyle,

I only tried to provide a explanation based on my assumption as to why the MTOW in the -400F may have changed post update. It is a fact that the limit was originally 875k and now is 850k in the freighter. Which also happens to match the non-stab tank equipped -400 limit. I would think if this was intentional, it was done because the revised CG model for the -400 without stab tanks (850k MTOW)  would also work with the -400F which cant be optioned with stab tanks to begin with.

13 hours ago, sosuflyer said:

Also just loaded up the sim and so far, all of my -400F variants have the 850K MTOW barrier in the FMC even though Boeing 2010 documentation says that the 610 MZFW option can have a MTOW of 875K. Just confused why all of this changed. I had my fleet planned out on pfpx, and all related weight options on a notepad on my desk, and now everything is mixed up.

You can still load the -400F to 875k without any problems/restrictions 🙂

 

20 hours ago, Ephedrin said:

I would understand the max amount of fuel to drop with the MZFW being increased. But why should the max TAKEOFF WEIGHT decrease while the amount of cargo goes up?? 20 Tons more of cargo means 20 tons less fuel at take off... but if the MTOW decreased it would mean for +20t cargo  --> -40t fuel?!

I guess I'm stuck... or took the wrong exit xD

The reason is quite simple! By loading up to the optional 635k MZFW, you are placing a lot more stress on the wing/body joints. The penalty for doing this, is limiting the overall weight of the aircraft to 811k. 

A similar concept applies to the Boeing BBJ family. The standard pressurization schedule is identical to that of the passenger -700/800/900. Typically 8000' of cabin altitude at FL410. 

For a substantial price, Boeing offers an alternative pressurization schedule option. With this, the cabin will maintain 6500' at FL410. 

The consequence of choosing this option is that the 50,000 cycle air-frame economic life is reduced for obvious reason to 26,000 cycles. (extendable by 50% with additional inspection intervals, at a even greater cost 😄) 

Edited January 16, 2019 by calzonister

[Ephedrin 418]

4 minutes ago, calzonister said:

you are placing a lot more stress on the wing/body joints

oooookay, thank you for that reminder. I absolutely missed the material point.

[Captain Kevin 586]

4 hours ago, calzonister said:

I hope the Boeing document I have linked below, helps you understand the relationship between either using the 635k MZFW or 875k MTOW. Loading the aircraft up to both limits simultaneously is prohibited due to structural limitations. 

Copy. I see what's going on now. A little surprised that the ACAPS wouldn't point this out.