747 V3 Fuel consumption problem

[tatin 0]

Hi,

lately it happens that in some flights the airplane has excessive fuel consumption. When I takeoff, I have 22000kg of estimated fuel on destination. But after taking off, that number drops 0,1kg every 4 or 5 minutes. 

I use PFPX, I load the winds to the legs page via the uplink, so I don´t know what could be wrong. 

 

Thanks,

[phil747fan 14]

no luck on you you got that with 777 and 744...

 

could you post your results including your flightplan and your report found?

[scandinavian13 5,192]

 

 

But after taking off, that number drops 0,1kg every 4 or 5 minutes. 

 

Since you crossposted this, I noticed you're seeing it in multiple aircraft. Sounds like you're suffering some sim pauses. Try lowering the settings in P3D for a flight to see how it handles it then. It may also be a BIOS issue.

[tatin 0]

Since you crossposted this, I noticed you're seeing it in multiple aircraft. Sounds like you're suffering some sim pauses. Try lowering the settings in P3D for a flight to see how it handles it then. It may also be a BIOS issue.

I am using fsx. It is weird because it only happens with the 777 and the 747v3. I own the 737 and ir Never happened such a thing.

[scandinavian13 5,192]

I am using fsx. It is weird because it only happens with the 777 and the 747v3. I own the 737 and ir Never happened such a thing.

 

Lower the settings in FSX then. Something is causing your sim to hang, and fuel is being drawn during this time.

[tatin 0]

Lower the settings in FSX then. Something is causing your sim to hang, and fuel is being drawn during this time.

ok. I Will give it a try. But I dont think that is the cause. Seldom does fsx hang. And if it does, it is just 2 ir 3 seconds.

Lower the settings in FSX then. Something is causing your sim to hang, and fuel is being drawn during this time.

The fuel prediction drops at a constant rate. It doesnt happen when it hangs.

[scandinavian13 5,192]

ok. I Will give it a try. But I dont think that is the cause. Seldom does fsx hang. And if it does, it is just 2 ir 3 seconds.

The fuel prediction drops at a constant rate. It doesnt happen when it hangs.

 

If I may...

 

You're here because you don't understand why your sim is behaving oddly. I support our products daily to know generally where to look. Sometimes it doesn't always make sense, but bear with me a bit and humor me.

 

Your computer's processor processes things so fast that it could finish things before you even knew it started. If some of that stuff is getting jammed up in the processor, you wouldn't even have to notice it for it to have an effect over time.

[harrry 322]

Now that is an answer with enough information to understand.  Often we get told do this and it seems to have no relevance.  Sometimes it is because the poster has misundertood the problem.  while lower the settings makes sense to you it does help that you have observed this as a problem.

[tatin 0]

I tried lowering the settings, but it keeps happening. 

If I may...

 

You're here because you don't understand why your sim is behaving oddly. I support our products daily to know generally where to look. Sometimes it doesn't always make sense, but bear with me a bit and humor me.

 

Your computer's processor processes things so fast that it could finish things before you even knew it started. If some of that stuff is getting jammed up in the processor, you wouldn't even have to notice it for it to have an effect over time.

I tried lowering the settings, but it keeps happening. 

[Ralgh 43]

The first thing I would do now is do a flight with clear skies and calm winds and check your fuel consumption. Take winds completely out of the equation.

[Kyle94 0]

Did anyone get this issue sorted? The same thing happened to me yesterday on a Delta flight from RJAA to PHNL. When I left Narita I had an estimated reserve of 55,000lbs and halfway through the flight, I had to divert because there was no way I'd make to Honolulu. When I landed in Guam I had a TOTAL of only 17,000lbs of fuel remaining. I followed the weights, altitudes, and speeds given by PFPX, yet the fuel reserve prediction continued to drop by 0.1 every 2-3 minutes. I doubt the cause was the 148kt tailwind I had, but that was the only anomaly (other than almost running out of fuel) throughout the flight.

[daguerreotype 5]

Hello, yes, I do have the feeling we have an overconsuption of fuel too on each long-range scenarios, and I had not this problem with other aircraft, because the discrepency between calcuted expected fuel and actual fuel at destination is very big, not the same order of number. But I don't have a metric to report pinpoint and normalised data.

Geoffrey Fernandez

[Kyle94 0]

5 hours ago, daguerreotype said:

Hello, yes, I do have the feeling we have an overconsuption of fuel too on each long-range scenarios, and I had not this problem with other aircraft, because the discrepency between calcuted expected fuel and actual fuel at destination is very big, not the same order of number. But I don't have a metric to report pinpoint and normalised data.

Geoffrey Fernandez

 

It's not just long-haul flights, I had an expected reserve of 42,000lbs of fuel on my flight from Taiwan to Tokyo, but when I arrived I had only 3,500lbs remaining. I don't know what's causing this, but PMDG needs to look into it.

[spesimen 135]

29 minutes ago, Kyle94 said:

It's not just long-haul flights, I had an expected reserve of 42,000lbs of fuel on my flight from Taiwan to Tokyo, but when I arrived I had only 3,500lbs remaining. I don't know what's causing this, but PMDG needs to look into it.

for anyone to reproduce your problem, you need to post a lot more details. is this 100% reproducible on your system? does it happen with no weather just ISA? what weather engine do you use?

also more details about which flight? what was the exact route and altitude? what was the load weight and fuel weights and predicted weights from pfpx? which model and engine type? what cost index was set, and what planning values did you use for the climb and cruise speeds? which pfpx profile are you using, is it the one that comes with pfpx or the updated ones that have been posted around?

it seems like what you guys are describing is pretty unusual !!!  so eliminating variables will be important in the long run. i glanced at this thread earlier while i was debating what flight to sim tonight and i'm flying RJAA->PHNL right now ...i set my fuel so pfpx predicts 55.8k lbs...and my FMS fuel prediction, rather than dropping, has gradually increased from 54.0 to 54.9 over the course of a few hours. i am using the 400F version with ge engines and ZFW of 602.5, original fuel load of 207259. that is with FSX-SE, AS2016 weather.

if this was a widespread issue there would probably be a lot more posts...it seems like there's something going on if it's more than a few people but i dunno... all my flights so far end up within around 5% of what was planned.. so i'm pretty sure that if you have found an issue it will be something specific to your settings or maybe some unique combination of factors.. hopefully the guys in this thread who have the problem can identify whatever it is they have in common. maybe post your hardware specs, OS, which version of fsx or p3d you are using, stuff like that too.

i still think finding a perfectly reproducable case on your system would be the first priority for identifying a solution

good luck!

cheers, andy crosby

[PerWel 23]

I have no problem at all with this.

Yesterday I did a flight from SBGR (Sao Paulo, Brazil) to FACT(Cape Town, South Africa), trip was estimated by PFPX to 3505 nm and minimum fuel 118683 Kg. Around 7 hour flight. It was with the 747-400 Virgin Atlantic Airways (G-VROM | 2009) with General Electric CF6-80C2B1F
PFPX also predicted that I would have 37.9 metric tons left on arrival.

But I did have ~40 metric tons left after TD. Also checked at some navpoints and fuel was very close to predicted.
I have also seen on shorter flights that PFPX is very close about fuel.

So there is something weird going on on your system, nothing wrong with the 747 and fuel.

PFPX 1.19, Yes old but works perfect, tried the later versions but had a lot of problems with them.
Win7 64 Professional, i5 3.8 Ghz 16Gb mem. Nvidia Gforce GTX 960 2Gb
FSX:SE, got it for only 70 Skr around $8. Better memory handling, not seen any OOM since upgrade. VAS goes up and down during flight, as it should. And better performance, FPS.