GW in the FMC

[jolmos]

In the FMC, GW is not updated by fuel consumption remains constant. Is adjusted manually only if loaded as residual fuel Fuel Plan at that time.

[Rodeo]

If you set plan fuel, GW will not update. You may set plan fuel to e.g. calculate V-speeds before refueling is complete, but you must delete plan fuel (once refueling is complete, IIRC preferably before engine start) if you want the gross weight to update again.