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PhilH

777-300ER performance/fuel question

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Hi,

 

I just purchased the -300ER expansion for my PMDG 777 using P3D earlier this evening. Works and looks really great.

 

 

First flight attempt for me is KSFO-NZAA. Basically, I use PFPX + TOPCAT together and figure out my fuel planning, it works great with the -200. I am aware that there is no -300ER extension for TOPCAT, so please let me know if my issue is caused by this.

 

So, for my flight...;

I just let PFPX find the route automatically, and then entered a random ZFW as I always do, followed by setting up ETOPS. For the ETOPS, I don't think I am 100% correct but I try to use the lowest ETOPS time possible (I have a couple of them I set up in the menus, 120min,240min,etc) and use the recommended airports until I get coverage over the entire ETOPS portion of my route.

 

This time, I got a message saying I was way overweight... long story short, even with 0 payload, my KSFO-NZAA flight is overweight using my ETOPS setup. I ended up just disabling ETOPS for this flight, and adding a random ZFW.

 

Here were the numbers that PFPX gave me.

EMPTY WEIGHT 167,829

PAYLOAD 52,171
ZERO FUEL WEIGHT 220,000  // 237,700 MAX
FUEL 126,987              // 145,523 MAX
RAMP WEIGHT LIMIT 346,987 // 352,400 MAX
TAKE-OFF WEIGHT 346,477   // 352,400 MAX
LANDING WEIGHT 240,591    // 251,290 MAX
UNDERLOAD 5,413           // LIM RMP

 

 
So here is my question: How does the real flight do it? According to flight aware, it is currently airborne using a 77W (which is the same as the -300ER as far as I know) and I don't think they can "avoid" ETOPS in real life... My ETOPS planning, after several attempts, still added 40 000 KG of fuel to my flight (which is probably where my mistake is), making me overweight.
 
 
I thought maybe my PFPX didn't have the right numbers for the -300, but they seem very correct. It had estimated I would arrive in NZAA with about 20k KG of fuel, and my FMC currently indicates I'll be there with 25k KG. I know the TOPCAT part doesn't have the proper numbers, but the fuel planning of PFPX should. Everything matches up with the numbers I found on Wikipedia.
 
 
I know this is more of a PFPX / planning question than a PMDG777 one, but if anyone more knowledgeable than me, please let me know why I can't even fly the route with 0 payload without being overweight.
 
Thank you very much!
 
Regards,

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Oh my, I feel like an idiot. I never realised the two text fields for ETOPS were pairings... I thought I just had more space to add 14 ETOPS airports instead of 7.

 

I just tried quickly messing around and if I put pairings, PFPX doesn't add 40 000 KGs of fuel. Great! Problem solved. I just need to figure out exactly what "pairings" do, because for now I just added random ones (but it worked). I'll do some more research. Thank you!!!

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I just tried quickly messing around and if I put pairings, PFPX doesn't add 40 000 KGs of fuel. Great! Problem solved. I just need to figure out exactly what "pairings" do, because for now I just added random ones (but it worked). I'll do some more research. Thank you!!!

 

Yup, I always pair up the ETOPS destinations in PFPX, such as NSTU/PHTO then PHTO/KMRY etc. Also you'll see a significant decrease in fuel carried to destination if you let PFPX auto select a Redispatch Point.  I just figured this out a few months ago and now use a RDP in the planning on all long hauls; I may select different airports but I found that the fix selected by PFPX yields the best solution.

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I just watched a couple of videos by Kyle Rodgers about PFPX on Youtube and they helped a lot. Turns out I just have no idea what I'm doing. Thanks for all the help, I'll continue watching ETOPS tutorials and also try to find out what exactly a "Redispatch point" changes.

 

Thanks,

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I just watched a couple of videos by Kyle Rodgers about PFPX on Youtube and they helped a lot. Turns out I just have no idea what I'm doing. Thanks for all the help, I'll continue watching ETOPS tutorials and also try to find out what exactly a "Redispatch point" changes.

 

Don't trust that guy...  :ph34r:

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Don't trust that guy...  :ph34r:

Haha. Thanks for the tutorials and for your time helping people who don't know what they're doing.

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Haha. Thanks for the tutorials and for your time helping people who don't know what they're doing.

 

Welcome - best way to learn is to teach, and I needed/wanted to learn a lot of this stuff.

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