Fuel consumption (PFPX vs PMDG 747)

[vlaskashirin 0]

I have noticed some serious difference between PFPX fuel calculations and PMDG 747 actual fuel consumption in flight. Turns out that a flight of about 10 hours consumes almost 10'000kg more fuel than PFPX planner predicts (taking into account the winds aloft, weight, etc). Does this mean that the fuel flow in aircarft.cfg file are off? Is there a way to even out the two so that planning is more accurate? Has anyone had the same problem?

Many thanks!

[scandinavian13 5,192]

Did you fly your flight with a Cost Index while PFPX is simply calculating a Mach-based cruise?

 

My first thought is that you're not properly matching the data.

[vlaskashirin 0]

Hi have tried both... I prepared the flightplan with cost index 100, Then another flight I did Mach .82. In both cases fuel calculations were off.

Basically when planning the flight in PFPX it predicts much lower fuel consumption for the flight but in reality the plane burns much more.

I have been thinking about perhaps adjusting the fuel flow in aircraft.cfg file in order to match it with PFPX.

[scandinavian13 5,192]

 

 

I prepared the flightplan with cost index 100

 

You're absolutely sure you set a CI of 100 into PFPX, specifically?  Most people's issues stem from not entering a CI into PFPX, but using a CI in the aircraft.

[Continental737 7]

I have also found that for the fuel to match up you need a BIAS of around 110%.

[Sascha91 0]

For me the best after a lot of testing in FS9:

aircraft.cfg Fuel Flow: 95.6

PFPX BIAS: 106%

During cruise mach .84

The Costindex data between PMDG 747 and PFPX are not correct.

 

regards

Sascha