Estimated fuel use at the gate.

[andysim 0]

So im sat at the gate with the engines off and apu running, plugged in the fuel figure (from PFPX) into the CDU and all is well with approx 5 tons fuel at the destination. then I push back and start the engines and suddenly get "Insufficient Fuel" warning, and only 1.1 tons at destination. is it just me?  Where did my 4 tons go? lol.

[davidz 26]

Two potential things at play here:

 

1. Did you plan the flight on the basis of a significant tailwind? If so, the FMC doesn't know about that so it will underestimate your fuel at destination.

 

2. If you are doing a turn around, there is a known bug where after you start the first engine, the FMC calculated fuel drops.

[77west 139]

5 tons seems a bit light, I can't speak for real world ops but I aim to land with around 7-10 tons.

 

Also RE tailwind, if you are using PFPX, don't forget to correctly export the wind .wx file and the import it via the LEGS FMC page! Otherwise FMC wont know about winds enroute...

[tcas_climb 45]

2. If you are doing a turn around, there is a known bug where after you start the first engine, the FMC calculated fuel drops.

And using saved panel states does count as a turn around.