There seems to be some confusion about how to get Simbrief to create an OFP in which the computed weights agree with those displayed by the PMDG B737. The required numbers appear to be buried somewhere in various config files and for all I know they vary depending on seating configuration, etc.

As it turns out, there's no need to go on an expedition through those files. Here's a link to a Simbrief airframe that I created that corresponds to the Southwest livery provided by PMDG.

https://www.simbrief.com/system/dispatch.php?sharefleet=10609_1652296323092

Here's how to create something similar for your favorite livery/configuration in Simbrief.

Click on the MY FLEET button at the top of the page.

Click on NEW AIRFRAME, then select the B737 from the dropdown menu. This gets you to a list of the options,  most all of which I will ignore. You probably want to indicate in the Notes/Comments block the aircraft configuration and livery you want to create an airframe for.

Now here comes the important part. All of the required data can be read from the CDU FS Actions pages as follows:

Max Passengers can be found by going to the PAYLOAD page. That number is the sum of those that appear after the slash under 1st class and economy.

OEW (Empty Weight) can be read off the ZFW and GW on the PAYLOAD page, just by setting passengers, cargo, and fuel to zero on the payload page and fuel page respectively.

MZFW (Max Zero Fuel Weight) was not changed. This could be determined by fiddling with the the ZFW in the vicinity of the default value given by Simbrief (121,700), but I was too lazy. When the ZFW goes over the maximum, it will turn orange on the PAYLOAD page.

MTOW (Max Takeoff Weight) is displayed on the PAYLOAD page

MLW (Max Landing Weight) was not changed. If someone can infer a more accurate value, please let me know and I'll change the linked profile

Max Fuel Capacity can be determined on the FUEL page by setting the fuel load to FULL

With regard to Passenger Weight I just filled the plane with 100 passengers and noted the difference in ZFW from the empty condition. It corresponded to an individual weight of 190 pounds which I believe is close to the latest average weight used by the FAA including carry-on baggage, so I set the Baggage Weight to zero. This means that whatever imaginary amount of checked baggage that there  might be, one would have to enter it into the cargo spaces on the PAYLOAD page.

Now Save the airframe and you're in business.

Hope this helps.

 

So I might be totally simplifying the issue is but all I do is take the ZFW from my simbrief profile (the 737-700 one that's already on the site) and enter it into the FMC - enter fuel and away I go, this changes the passengers accordingly but all the weights still match?  I couldn't care less if the pax on the OFP is different from the the FMC as long as the ZFW matches?  Right or wrong?

Yes, I believe so. Of course, you wouldn't have the fun of messing with the cargo distribution and CG, but really the ZFW and fuel are quite sufficient.

Thanks for the profile link. Saving this for later!

If you want to "tune up" your fuel consumption numbers, write down the actual vs "burn" as stated on the OFP for 4 or 5 flights. add up the 2 columns, divide the actual total used by the planned total and it will give you a percentage. You can adjust the "Fuel Factor" in the airframe profile to compensate. Say you calculate that you burned 95% of the fuel that was planned for those flights, you can input "M05" in the fuel factor, and Simbrief will lower its planned fuel for that airframe by 5%. Record the numbers for another flight or two and do the calculation to see if you are close to 100%.