Fuel remaining

[Driver170 42]

ust setup a flight from EGPH to LPMA in the 737NGX 800W.

 

I'm using latest update on PFPX and using ASN also for weather.

 

This is the first time i have seen such a split between PFPX fuel at dest and the NGX FMS prediction.

 

PFPX OFP says i'll arrive with 2555 and the NGX shows 3800kg or 3.8t

 

I'm using CI 6 climb/des profile is 250/280/78

 

i setup the PERF INIT with CI of 6 and CRZ WIND.

 

My weights match - ZFW 55226kg

 

just can't find why the reason?

[BrianW 124]

Winds aloft different from forecast?

[Driver170 42]

No they all match up.

[pcubine 143]

i setup the PERF INIT with CI of 6 and CRZ WIND.

 

Vernon

 

Maybe you need to enter the wind direction/speed by waypoints. What are you entering in CRZ WIND? I never use CRZ Wind unless it is an extremely short flight of a couple of hundred miles. I enter the wind direction/speed on the RTE DATA page by waypoint. If you are using an average provided by ASN it is incorrect. It is a straight average and not a weighted average for distance between waypoints. The developer of PFPX said the average is weighted but it is only of the speed with no direction. See Tutorial 2 starting on page 135, Cruise Wind Entry.

[Driver170 42]

Hi, for CRZ wind i enter TOC wind on my LIDO OFP. Then at TOC i enter the winds in the legs page for each waypoint if its greater than 10kts or 10 degrees. Short sectors i only enter the TOC wind

[Ernom 0]

I've just finished IVAO IFR WorldTour with the PMDG 737 NGX. Using PFPX+Tomcat for fuel calculation based on real weather data, I've finished most of my flight within a few % difference from the planned fuel quantity. 

[Driver170 42]

What fuel Bias are you using?

[Driver170 42]

Seems like using a lower bias 100 is useless for short sectors and using higher bias like 103 for longer sectors leaves more fuel than PFPX predicts.

[pcubine 143]

What fuel Bias are you using?

It doesn't make any difference what anyone else is using for fuel bias. Your A/C might be the same or it might be different. You need to do a fuel evaluation to determine your bias. In PFPX Aircraft Manager>Administrate>Select Aircraft>Edit>Bias is where you can determine your fuel bias. There are several threads in the PFPX Forum on how to use the evaluator.

Seems like using a lower bias 100 is useless for short sectors and using higher bias like 103 for longer sectors leaves more fuel than PFPX predicts.

[Driver170 42]

Not sure where your going? But i'm not asking about how to find the Bias i already know that. Would like to know for the 800W what everyone else is using. So it does matter if they are using the same variant as me.

 

Seems like you can't have the perfect Bias, because on long sectors using 100 works great, however on short sectors it will leave you short and going into reserves.

[pcubine 143]

Not sure where your going?

I thought you fixing to use Ernom fuel bias.

[Driver170 42]

If i plan a flight in a TW for example i done a flight from, EGPH to EGSS in a TW. I use ASN and P3D V3.2 And also the 737 800W NGX.

 

It seems like doing a flight in a TW is leaving me short of fuel and putting me into reserves before reaching the DEST. However if i do the flight from EGSS to EGPH in a HW both PFPX fuel is sufficient to complete the flight without going into reserves and i land with 2100kg unlike the flight to EGSS where i landed with 1500kg.

 

So seems like the TW is the culprit in the calculations but i can't figure it out why?

 

I hope this makes sense, but something is wrong here.

 

I have setup my NGX 800W weights per that guys topic on aerosoft matching weights. I use the same CI6 and FL. All data matches before someone asks.

 

The thing is, i done the flight from EDI-STN and NIL wind in PFPX and CAVOK no wind in ASN and all my fuel burn and fuel on board matched perfectly