MCDU Large difference in Trip Time/fuel compared to Simbrief

[aceridgey]

Hi there,

Please see difference in mcdu and pfd attached trip fuel.

 

Full route with SID/STAR is programed correctly but i am getting wildely different figures.

 

Additionally, my TOC on my last flight was very ambitious compared to what was acheived in the sim.

 

I am using the simbrief Inibuilds A300 (selectable option).

Any ideas?

EGLLEBBR_PDF_1707573553.pdf

[Deleted Account]

We will take another look at the simbrief profiles, but realistically I don't think creatign a 100% accurate is possible due to winds etc.

[aceridgey]

Thanks Nico, 

Please do indeed have a look at it.. I'll continue to test in the meantime but the example I did give was with the planned winds uploaded. 

 

Kind regards 

Alex 

[Crabby]

On 2/10/2024 at 8:15 AM, aceridgey said:

Any ideas?

GLLEBBR_PDF_1707573553.pdf
572.86 kB · 2 downloads

My idea?  Embrace the suck.  Real life is not digital (yes/no, on/off, fuel off/fuel spot on) it is analog with all the variations of living a waveform can give.  Winds on an OFP are PREDICTED.  Trip fuel is PREDICTED.  TOC is PREDICTED.  Even ZFW is ESTIMATED (same as PREDICTED).   Were you still at the gate?  I remember one flight I did from KPHX to PHNL.  I was in a 757.  I loaded up everything per Simbrief route, winds, loaded the plane exactly as dispatched.  Hit execute on the FMC and it told me I was short 20,000 lbs of fuel.  What did I do wrong?  What was wrong with the plane?  What was wrong with Simbrief?  Nothing, I landed in PHNL with 10,000 lbs of fuel.  As I watched the flight progress it was as if I had a fuel generation plant on board.  Fly the flight and then see how it ended up and whether there are additional adjustments to make.  My arrivals have always been within acceptable tolerances of where they were supposed to be.  

[aceridgey]

6 hours ago, Crabby said:

My idea?  Embrace the suck.  Real life is not digital (yes/no, on/off, fuel off/fuel spot on) it is analog with all the variations of living a waveform can give.  Winds on an OFP are PREDICTED.  Trip fuel is PREDICTED.  TOC is PREDICTED.  Even ZFW is ESTIMATED (same as PREDICTED).   Were you still at the gate?  I remember one flight I did from KPHX to PHNL.  I was in a 757.  I loaded up everything per Simbrief route, winds, loaded the plane exactly as dispatched.  Hit execute on the FMC and it told me I was short 20,000 lbs of fuel.  What did I do wrong?  What was wrong with the plane?  What was wrong with Simbrief?  Nothing, I landed in PHNL with 10,000 lbs of fuel.  As I watched the flight progress it was as if I had a fuel generation plant on board.  Fly the flight and then see how it ended up and whether there are additional adjustments to make.  My arrivals have always been within acceptable tolerances of where they were supposed to be.  

Mark, I am not saying the numbers need to be bang on the money, but I'm demonstrating a large difference between the two.. In the real aircraft on this situation, it wouldn't dispatch. 

[bajaj94]

I notice this every flight as well. The INIT B page seems to have numbers that are very different from both the Simbrief profile as well as what the plane actually does. To me, the plane and the simbrief profile seem to be close enough to each other, it’s just the INIT B page that seems largely different. I’ve also noticed that the trip time is usually wrong as well, which might be where the bad fuel predictions stem from.