Erikk 7 Posted September 7, 2013 Share Posted September 7, 2013 Hi there, I am very happy with PFPX. And I always use it now with flight planning. At the moment I am flying with the new PMDG 777. I planned a route with PFPX from EDLL to KIAD, and did also the fuel calculations. Now when I am flying it. I see in de FMC that the remaining fuel at KIAD is 12.7, but PFPX told me that I arrive with 7.6. All weight in KG. Yes, I used the WX:online weather and wind with the planning. And I use ASE 2012 in FSX. But I hope that ASE not cause this problem. So how is this possible or what did I wrong? Erik Link to comment Share on other sites More sharing options...
heidem 5 Posted September 7, 2013 Share Posted September 7, 2013 The difference is probably caused by the winds being different from the forecasted winds. Link to comment Share on other sites More sharing options...
ajurt 3 Posted September 7, 2013 Share Posted September 7, 2013 Erik, Heidem is right, that could be one reason. I don't own PMDG 777, but can you enter forecasted winds into the FMS? If so, that will give you a much better calculation. Also, I believe the fuel figures from PFPX are from the real plane and I don't know how close PDMG comes to that. If you really want to be precise about it, do a flight with no winds, compare the PFPX fuel figures at each waypoint with PMDG and then adjust the climb / cruise / descent % values in the aircraft profile. Andre Link to comment Share on other sites More sharing options...
Erikk 7 Posted September 7, 2013 Author Share Posted September 7, 2013 mmm, yes okay, but it's not the calculations from PMDG, but I arrived with 12.7 and PFPX gave me 7.1. Link to comment Share on other sites More sharing options...
ajurt 3 Posted September 7, 2013 Share Posted September 7, 2013 Erikk, OK, let's assume the winds in the forecast and the winds accually encountered are roughly the same, that means PMDG is using less fuel than the real 777. You should create a PMDG 777 aircraft template and adjust the climb / cruise / descent percent values accordingly. For example, let's say the PFPX burn was predicted at 45'000 kgs but you only used 40'000 kgs, that means you're burning 11.1 % less fuel than predicted. You could set each value to 88.9 % but I think you're much better off if you compare the predicted / actual fuel burn for each segment (climb / cruise / descent) as that will be much more accurate. Andre Link to comment Share on other sites More sharing options...
Biermuskel 8 Posted September 8, 2013 Share Posted September 8, 2013 got the same issue with the 777 from pmdg and pfpx.. the different fuel calculation is very strange.. and it isn't possible that just because of wind the fuel calculation is so much different. Link to comment Share on other sites More sharing options...
Chaders 97 Posted September 8, 2013 Share Posted September 8, 2013 Eric, Just for my own interest what was your planned Block and trip fuel. Be handy to know what the Block time was just so I have an idea what the difference in burn was per hour. Whilst arriving with 5100 kgs more fuel than your OFP expected might seem a lot if it was a very long sector you flew this could certainly be underburned if the winds weren't as forecast. Link to comment Share on other sites More sharing options...
phil747fan 52 Posted September 8, 2013 Share Posted September 8, 2013 Erikk, OK, let's assume the winds in the forecast and the winds accually encountered are roughly the same, that means PMDG is using less fuel than the real 777. You should create a PMDG 777 aircraft template and adjust the climb / cruise / descent percent values accordingly. For example, let's say the PFPX burn was predicted at 45'000 kgs but you only used 40'000 kgs, that means you're burning 11.1 % less fuel than predicted. You could set each value to 88.9 % but I think you're much better off if you compare the predicted / actual fuel burn for each segment (climb / cruise / descent) as that will be much more accurate. Andre Erikk, OK, let's assume the winds in the forecast and the winds accually encountered are roughly the same, that means PMDG is using less fuel than the real 777. You should create a PMDG 777 aircraft template and adjust the climb / cruise / descent percent values accordingly. For example, let's say the PFPX burn was predicted at 45'000 kgs but you only used 40'000 kgs, that means you're burning 11.1 % less fuel than predicted. You could set each value to 88.9 % but I think you're much better off if you compare the predicted / actual fuel burn for each segment (climb / cruise / descent) as that will be much more accurate. Andre This +1 ... datas from PFPX are top notch maybe PMDG is not 100 per cent due to fsx limitations or datas not used .... all the best. Phil Link to comment Share on other sites More sharing options...
FlightSimSoft.com 283 Posted September 9, 2013 Share Posted September 9, 2013 The easiest way to adjust fuel burn for your add-on is using the Evaluate function in the aircraft editor. Go to the Aircraft Editor Edit the desired Aircraft Click the Evaluate button Enter fuel burn data from your Flight Simulator in straight and level flight PFPX will propose a bias value for an adjusted fuel burn Link to comment Share on other sites More sharing options...
Stuart McIntyre 3 Posted September 9, 2013 Share Posted September 9, 2013 christian, would you advise doing an evaluation on a regular basis to ensure that profile burn is accurate? or would it just be sufficient to do it once for each aircraft? currently I am quite happy using the profile provided by PFPX but if it would improve accuracy even more i may start doing this with my fleet Link to comment Share on other sites More sharing options...
FlightSimSoft.com 283 Posted September 9, 2013 Share Posted September 9, 2013 Most accurate would be to perform the evaluation at an 'usual' cruise altitude with an 'usual' cruise speed. Once this is done, there is no need to do regular further evaluations. If, during several flights you notice an over/-underburn, Bias values can be adjusted accrdingly. Link to comment Share on other sites More sharing options...
Stuart McIntyre 3 Posted September 9, 2013 Share Posted September 9, 2013 many thanks, I will start doing this today. will take me a while until I fully understand the whole climb/cruise/descent bias correctly, I am just in awe of your software, thank you for your help Link to comment Share on other sites More sharing options...
jeffrds 0 Posted September 11, 2013 Share Posted September 11, 2013 Guys, you have always to take forecasted winds into consideration. Yesterday, I did a flight from EGLL to KJFK with the 777pmdg, using PFPX's forecast data + opusfsx (both use NOAA Gribs), I inserted all the wind information per waypoint tha the OFP provided, and the difference in fuel at New York was of only 700kg, that's right, less than a ton of fuel from the predicted fuel burn. PFPX is a very powerful tool, and it's 777pmdg profile is spot on. But, on such long stints, winds forecast take a big spot in the final fuel burn, so always insert them on the Legs/RTE Data section. Cheers. Link to comment Share on other sites More sharing options...
Simul8 12 Posted September 11, 2013 Share Posted September 11, 2013 Bear in mind that it's not unheard of in the real world for the forecast* winds to be so far out of whack on the Flight Plan that you occasionally land with three or four tonnes more than you had planned. Conversely, it has happened where the arrival fuel was a few tonnes less than planned too. In those instances though, the reality of a divert for fuel rears its head.... Oh the paperwork! Cheers Smiffy * Forecast - Definition - verb (past and past participle forecast or forecasted) [with object] predict or estimate (a future event or trend):rain is forecast for Scotland[with object and infinitive]:coal consumption in Europe is forecast to increase noun a calculation or estimate of future events, especially coming weather or a financial trend. Link to comment Share on other sites More sharing options...
mopsfidel 0 Posted September 19, 2013 Share Posted September 19, 2013 Hi there, I am very happy with PFPX. And I always use it now with flight planning. At the moment I am flying with the new PMDG 777. I planned a route with PFPX from EDLL to KIAD, and did also the fuel calculations. Now when I am flying it. I see in de FMC that the remaining fuel at KIAD is 12.7, but PFPX told me that I arrive with 7.6. All weight in KG. Yes, I used the WX:online weather and wind with the planning. And I use ASE 2012 in FSX. But I hope that ASE not cause this problem. So how is this possible or what did I wrong? Erik Hi Erik, as ASE 2012 user you might find this video very interesting (should start at 2:53): http://youtu.be/fMrW4O4WXYY?t=2m53s The video shows how to export wind data from ASE 2012 and import it to PMDG 777. When the export is explained you may jump to 14:30ish to see how it is imported into 777. Andy Monroe Link to comment Share on other sites More sharing options...
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