Fuel calculation with Simbrief

Hello, yesterday again my OFP TTPP-KAUS was giving me 17.1 T of fuel which was not enough to destination and the aircraft crashed. Around 8 out 10 OFP using either A310 Inibuilds or Toliss A321 gave me the same issue (6 times with less than 1 T of fuel on board), 1 flight diverted and this crash. Is something has changed? I’m using simbrief since the beginning and never experimented this issue before!-). Any hint would be appreciated.
Windows 10, X-plane 11.55r2,last AiracXXX8

Hi, nothing has changed on SimBrief’s end, and I have no other reports of this. A few things you can check:

  • You’re dispatching in KG. Make sure your simulator/aircraft are also in KG. If they are in LBS and you enter the KG figure, you’ll end up with half as much fuel as required.
  • Make sure you match SimBrief’s ZFW with the actual aircraft ZFW in the sim. Heavier aircraft burn more.
  • Make sure you’re cruising at or close to the same altitude and speed as planned. Big altitude and speed differences can have a big difference on long flights.

I also noticed for your A321 aircraft you have set the fuel factor to M13. How did you come to this figure? Perhaps this needs to be revised if the A321 in your simulator has been updated to burn more.

Hi, thank you for answering
Yes en KG always
Matching the ZFW number when possible. Sometimes Number from OFP is too high for the aircraft and I have to reduce it.
Always marching altitude.
Where did you see the M13 for the A321 and what does that mean exactly? Thank you again

What do you mean by “sometimes number from OFP is too high”?

Exemple if the ZFW is 120,500 (according to the OFP) the aircraft won’t accept it and a red message will be coming up (at least for the Inibuilds A310), so I will lower the ZFW number

Of course, because you are inserting a too high Zero Fuel Mass (ZFM).
According to Simbrief’s database, the Maximum Zero Fuel Mass (MZFM) is 114.020 kg.

Personally I would say you are not aware of the limitations and what exactly you are requesting in terms of flight planning.

No problem, we’re here to help :slight_smile:

The M13 fuel factor can be edited in the options when creating your flight. Simply set it back to the default of P00 if you find SimBrief is planning too little fuel:

And if you want to change the default fuel factor when using this aircraft (so that you don’t have to change it in the flight options each time), you can modify it by going to the My Fleet section, loading your A321, then changing it back to P00 (the default):


Best regards,

I’m afraid you are totally right! I will be digging thoroughly on this subject from now on. Thank you

Thank you very much for the explanation! I guess it won’t happen to me again!-)