BW901

The main obvious difference of the 747-400D is that they were not fitted with winglets. On most Boeings which had winglet option as retrofit the fuel burn saving is around 3-4%, so the burn on the 400D will be higher. On the very short domestic sectors those aircraft flew the additional burn wasn't huge and was offset by weight saving without the winglets and maintenance benefits. I believe that the D also had lower fuel capacity and different weights, but someone more knowledgeable than me may know better. Of course this all assumes that PMDG have a specific flight model reflecting the differences of the D. If not then it'll fly like a standard -400 in the sim anyway.

My apologies if it's an inconvenience that the site is down. Unfortunately at the moment I'm having to spend time lifting floors and working on a house rather than looking at a screen. I think my PC's are getting withdrawal symptoms. In the meantime for anyone who has airlinerperformance files please keep using and enjoying them, but I would ask that you do not (re-)distribute them. Cheers Jon

If memory serves the 550 is a recofigured 700. Revising (reducing) 700 weights and seat capacity etc should work.

Thanks Gentlemen. It's over so quickly! Phil are you back in the freezing north? B767-200 engine variants for the Flightfactor uploaded now. Although said to be -200ER by FF, the weights in the EFB are representative of a standard aircraft, so I've gone with lower numbers to match the EFB. As with all these you can edit payload options, weights and fuel figures to match your own flight model or airline preferences within PFPX in any case.

Merry Christmas folks. A couple of presents up at airlinerperformance.net ahead of the big day. Profiles for the newly-released A321 are uploaded and the first variant for the Flightfactor 767, the -300ER with RR engines is also up. These have CI data for climb, cruise and descent - interestingly looking at Twitch streamers no one ever seems to use CI on climb or descent. More 767s to follow. Also with the Milviz 350 out this week I've written a file for that (temporarily) linked here KA350i. I've fudged the perf at low weights so would be interested if anyone with that aircraft wants to try it and let me have any feedback. Once I know it's OK I'll put it on the site and remove the link here. Cheers!

File uploaded at www.airlinerperformance.net

Well you found me Loic 😉 No promise on how long, but if I can find a few hours this weekend, I'll run up a profile. Cheers Jon

Folks, profiles are built, but I've had a computer issue which will cause some delay. That's just about resolved, so hopefully files will be uploaded to airlinerperformance in the next few days once I've done a bit of testing. Thanks @AirbusCG for the polite and considered post there, and @donkey for the website check!

Matching Takeoff Weight is the bit that matters. The total weight of the aircraft is what drives the performance and fuel burn, irrespective of how that total weight is made up. You add bias through the Aircraft Editor. Select the relevant aircraft in the Aircraft Database and then select Edit. Type the bias into the relevant data entry box, make sure you save when you have changed the appropriate value. APM has nothing to do with what we're proposing here, simply type in the suggested values. If you are finding that the TOW in your sim and in PFPX aren't matching then my suggestion is remove any bias. Do a flight with matching weight, see what percentage the burn in climb and cruise differs and type that into the Aircraft Editor. Keep things simple. One other thing just to be sure nothing external is messing with your PFPX setup - did you use a template to create the aircraft? Using a Template to create an aircraft rather than creating straight from the performance file can sometime cause problems, personally I never use them, and I don't provide templates, only the .per files.

Ray, I've never used drag bias - that may then also affect speeds. It is very hard to understand what's happening without seeing the whole picture. Fuel burn is only one element in the whole equation. The ideal would be if we had the OFP used as it is in the real world, as a How-gozit. With actual time and fuel, and some IAS/TAS/wind checks annotated onto a printed OFP it would be much easier to see exactly what's going on. However I appreciate that's something that only a few simmers would ever do. Sorry if I'm repeating what Stephen has already asked and for doing the IT equivalent of "is it plugged in" but - 1. Does your PFPX weather match whats in the sim? 2. Does your takeoff weight match between PFPX and the sim - forget all the underlying fuel, weight, ZFW, etc, it's the TOW which is going to drive things. I just ran a 2 hour sector at a few different weights and the % increase in TOW results in a similar % increase in fuel burn. 3. PFPX and sim aircraft types match (winglet/non-winglet) Otherwise based on your typical flight examples bump up the PFPX Climb fuel bias to around 10%, increase the cruise bias slightly, to maybe 7-8%, add an extra couple of hundred pounds for ATC getting you down low early on the approach and you should be there. Jon

Ray, If you remove that bias, PFPX's calculated fuel is going to reduce - by 5.6% or typically somewhere around 100kg for the climb segment. That is only going to increase the differential between PFPX's burn and your sim burn. At the moment given the way your sim is behaving you'd be wanting to increase the climb bias to somewhere around 10%. Something is not right, because your sim burn is high in all three flight phases, even in the descent you're burning 200 (units on the bar chart?) more than PFPX's calculation. I no longer have P3D installed, I now only use X-Plane, so I can't take a look I'm afraid. Jon

At higher weights a 738 is going to consume somewhere between 1700 and 2000kg getting up to typical altitudes (and I've just been looking at a bunch of realworld OFPs to verify that). That matches the numbers in the performance file. You appear to have already added 5.6% fuel bias on the climb. If you are saying that you're burning a few hundred lbs more than that in the sim.... I'd say CI 45 or 35 is high for normal planning purposes, but I'm open to correction. Every OFP I've been looking at is between 10 and 20. Having said that Climb at CI40 vs CI10 only adds about 3% to climb fuel burn.

Forgive me if I've misread the numbers but for EBBR-EDDM it seems that PFPX calculated a trip burn of 5400lbs, vs PMDG's actual burn of 5500lbs (read to the nearest 100 lbs?). That's a 100lb (45kg) difference, or about 1.8%. To quote - "GIven the cost of PFPX and the PMDG737 it's disappointing the calculations / usage aren't more accurate" Seriously ??!! What's causing the bigger variance in point numbers is a 200 lb higher start/taxi burn before departure. Irrespective of how PMDG or FSX/P3D models burn on the ground or at low thrust BRU is a big airport, it would be normal practice to apply a higher fixed taxi fuel allowance at larger/busier airports. As for the FSX/P3D fuel burn vs temperature issue, I did post a good while ago asking for folks wanting to help with testing revised files. I had one reply for 1 aircraft type, and didn't get any feedback on the revised performance file. It would seem that 99.9% of users aren't that bothered, which seems to be borne out by how the majority of Twitch streamers use/apply both flight planning applications. Cheers Jon

Stephen, no worries, thanks for your continuing support

Hi Stephen, to avoid 'busflyer some confusion, the file on Airlinerperformance is for the Fokker 50, not the DA50 (Dassault Falcon 50)! I have produced files for the Falcon jets, but not publicly released any of them. Cheers Jon