Spot on Alex! Looks like the T7 and PFPX are good to go, thanks for sharing  :smile:

 

Shane/Charlie/Craig...I found what I believe to be the answer to the weight stuff for the NGX:

 

http://forum.avsim.net/topic/417842-topcat-pfpx-737ngx-weights-how-to/

 

Basically verifies that the stock weights in both Topcat and PFPX need to be adjusted for the NGX....Glad I found it before doing my test, this method looks solid, going to set mine up this way and do some flights.

Craig,

 

I havent the time to try and test it, but Its just a matter of matching the true NGX, OEW weight, combined with the NGX weight for passengers and telling PFPX that.  Poke around the NGX's .cfgs to find the OEW weights and modify PFPX aircrafts profile with that OEW. Also you need to ensure that PFPX is using 175lbs per passenger.   

 

That "should" make everything match, however I cant confirm that at the moment.  However Jeff seems to have been able to confirm this.

 

Also, Im not at all concerned about fuel burn figures being off, since they should be off, its not a perfect science. And PFPX is very accurate to say the least. One only needs to make sure they are meeting min fuel requirements, and that the fuel is not trending downwards consitantly through out the flight (fuel leak).

 

Solid work guys!

Those weight numbers look good and match what I've found.  The only number that I could not find on that list is the "Max Ground Weight".  Can that be calculated from the other parameters?

 

BTW - Using the FMC and setting the number of pax to 0, and then changing it to 100 I see an increase of 17,500 lbs ZFW which would seem to confirm that PMDG is using 175 lbs as the weight per passenger. So in PFPX I have changed the weights for adults and children to 175 (infants are not included in the pax count shown on the OFP).  One thing to be careful about is to add the baggage weight and cargo weights shown on the flight plan to get the total non-pax payload that needs to be distributed between the fwd and aft cargo compartments.  I modified the OFP template so that both weights show up on the my OFP (pax*175+cargo+bags = Total).

 

 

Good stuff Charlie,

Based on the settings from the post I linked, the tweaks to the EW-MZF-MTO wind up updating the MGW (Max Ramp Weight) in both PFPX and Topcat. Which is contrary to the way I was originally setting it up as per Chris Palmer's guide from AOA. That being said, I did a flight with the settings from Al's post and my numbers across the board were spot on across all three. Was really cool having PFPX and Topcat matching so nicely and then having the NGX so closely match the PFPX numbers was great. Still trying to grasp all of this, as I am no expert by any means. Having PFPX for the all things planner and Topcat as the performance tool is cool.

 

Would you mind showing the baggage code snippet from the OFP template you made? I know I read in the PFPX forum that <&baggage> is the string to use for adding that to the OFP template, curious as to the formatting you used.

 

Thanks.

Ever since Ryan created the advanced tutorial #2 for the NGX, I have been computing my fuel load for the NG with the most accurate fuel planner out there, the FMC itself.   The idea here is that the real life dispatchers use a desktop version of the FMC software when they compute fuel loads and routes.   I also remember PMDG's resident aeronautical engineer guru who worked behind the scenes on the mathematics behind the NGX flight model claiming the FMC is the go to tool.   Now, with the release of PFPX, how confident is PMDG in using PFPX as the sole source of fuel computations?   I understand there may be some slight differences between the FMC and PFPX figures, but I would hate to not use PFPX as intended, and it seems more realistic to use a professional dispatch program versus in the aircraft FMC.

 

Should we trust PFPX when it comes to the NGX and soon to be released 777 for computing fuel? 

 

One thing to note, is the fmc is only accurate in that way if you haven't planned for winds aloft, temperature etc. One would have to import that data to make the fuel estimate accurate. PFPX takes it to the next level with winds aloft, cruise temperatures, alternates etc. etc. the list goes on.

OFP.JPG

For what it's worth, the REEDR3 arrival for LAX is only used when in East ops (fairly rare, wind has to be consistently out of the East at 10 kts or more) Normally you'd want the RIIVR2, or the RDEYE2 if it's between 0000-0700 local and noise ops are in effect (land 6R / depart 25R if weather is good)

You can trust PFPX with your life. The parameters for the 772LR was given to the developers directly from PMDG which again got them from Boeing. Just make sure you have updated the nav-database to 1309 and you should be all set!

 

I'm really looking forward to planning the DXB-SFO route and see how good it really is

 

Need to correct this here - what I gave Christian are the various weights and fuel/payload figures for our 777. We most certainly did not give him the actual FMC prediction software that runs in the airplane...

 

I have noticed PFPX overestimating fuel burn compared to our 777 - there are variables that PFPX exposes when you create an aircraft to bias the fuel burn in each phase of flight and so on. Those will need to be adjusted and I'm sure once the release happens people will figure out the correct values pretty quickly. I just haven't had time or I'd have messed with it myself.

 

I believe this is how real life dispatch tools actually work as well - there's a simplified model (not the real life FMC code) running in the program and they use these bias values for each airplane's tail number to make the model essentially agree with the real airplanes. There were a ton of real life dispatchers involved in the creation of PFPX, so I have to assume this is how it actually works.

Need to correct this here - what I gave Christian are the various weights for our 777. We most certainly did not give him the actual FMC prediction software that runs in the airplane...

 

I have noticed PFPX overestimating fuel burn compared to our 777 - there are variables that PFPX exposes when you create an aircraft to bias the fuel burn in each phase of flight and so on. Those will need to be adjusted and I'm sure once the release happens people will figure out the correct values pretty quickly. I just haven't had time or I'd have messed with it myself.

 

I believe this is how real life dispatch tools actually work as well - there's a simplified model (not the real life FMC code) running in the program and they use these bias values for each airplane's tail number to make the model essentially agree with the real airplanes. There were a ton of real life dispatchers involved in the creation of PFPX, so I have to assume this is how it actually works.

 

That kinda gave me an idea what the "Burn Bias" meant. What's the bias percentage you'd recommend during climb and descent phases?

 

Cheers,

Need to correct this here - what I gave Christian are the various weights for our 777. We most certainly did not give him the actual FMC prediction software that runs in the airplane...

 

I have noticed PFPX overestimating fuel burn compared to our 777 - there are variables that PFPX exposes when you create an aircraft to bias the fuel burn in each phase of flight and so on. Those will need to be adjusted and I'm sure once the release happens people will figure out the correct values pretty quickly. I just haven't had time or I'd have messed with it myself.

 

I believe this is how real life dispatch tools actually work as well - there's a simplified model (not the real life FMC code) running in the program and they use these bias values for each airplane's tail number to make the model essentially agree with the real airplanes. There were a ton of real life dispatchers involved in the creation of PFPX, so I have to assume this is how it actually works.

It's worth pointing out that the burn bias is not just because the model is simplified, but also because of differences between airframes (e.g. amount of engine wear, added weight from repairs, small dings or dirt adding drag, etc). That's why the burn bias is determined for each tail number separately. I can imagine advanced systems would also track the individual engines (since those don't always stay with the same plane due to differing maintenance cycles), but I'm not sure of that.

 

 

 

Need to correct this here - what I gave Christian are the various weights and fuel/payload figures for our 777. We most certainly did not give him the actual FMC prediction software that runs in the airplane...
 
I have noticed PFPX overestimating fuel burn compared to our 777 - there are variables that PFPX exposes when you create an aircraft to bias the fuel burn in each phase of flight and so on. Those will need to be adjusted and I'm sure once the release happens people will figure out the correct values pretty quickly. I just haven't had time or I'd have messed with it myself...............

 

Very good to know, I have not yet had time to play with the bias stuff either, with regards to using the NGX with PFPX. Excellent info Ryan, thanks for sharing this. 

Jeff - Here is the section of my modified OFP template that adds the baggage weight (I had to tinker quite a bit to get the spacing to display correctly):

 

--------------------------------------------------------------------------------

CONFIG      DOW  PAX  CARGO/BAGS   TOTAL ULOAD LIM       ZFW     TOW     LDW

<&Configuration:8> <&DOW:6>  <&TotalPax:3><&Cargo:6>/<&Baggage>  <&Payload:6><&Underload:6> <&UnderloadLimit:3>   MAX  <&MZFW:6>  <&MTOW:6>  <&MLDW:6>

                                                    PLN  <&ZFW:6>  <&TOW:6>  <&LDW:6>

                                                    ACT  ......  ......  ......

<&PerformanceSection_Begin>

--------------------------------------------------------------------------------

 

Steve - Thanks for the heads-up on the STAR.  This is the plan that PFPX gave me and I never bothered to check it out.  BTW - What is the best source for current SID/STAR standards?

Those weight numbers look good and match what I've found.  The only number that I could not find on that list is the "Max Ground Weight".  Can that be calculated from the other parameters?

 

BTW - Using the FMC and setting the number of pax to 0, and then changing it to 100 I see an increase of 17,500 lbs ZFW which would seem to confirm that PMDG is using 175 lbs as the weight per passenger. So in PFPX I have changed the weights for adults and children to 175 (infants are not included in the pax count shown on the OFP).  One thing to be careful about is to add the baggage weight and cargo weights shown on the flight plan to get the total non-pax payload that needs to be distributed between the fwd and aft cargo compartments.  I modified the OFP template so that both weights show up on the my OFP (pax*175+cargo+bags = Total).

 

OFP.JPG

How do you make PFPX show the baggage load? i can Only see the Cargo load? thanks.

Unless you have modified the OFP, you have to go back to the PFPX flight plan page.  The baggage load weight is next to the cargo load.  When you have the two weights, add then together and distribute the total into the fwd and aft cargo holds.  If you have changed the PFPX weight table to show 175 lbs for adults and children the correct passenger weight can be entered into the NGX by simply setting the number of passengers to the PAX number in the OFP.

 

Steve - Thanks for the heads-up on the STAR.  This is the plan that PFPX gave me and I never bothered to check it out.  BTW - What is the best source for current SID/STAR standards?

 

No problem. I know about LAX off the top of my head because I'm a Vatsim ZLA controller. I usually use flightaware to check US routes.

 

Jeff - Here is the section of my modified OFP template that adds the baggage weight (I had to tinker quite a bit to get the spacing to display correctly):...........

 

 

 

 

Thanks Charlie !