ZFWCG weight and balance

777Driver · January 11, 2026 at 10:13 AM

ZFWCG changes when fuel is reduced in the menu. I appreciate that the whole fuel system will eventually be redesigned. Is the sim currently just looking at overall gross weight, instead of adjusting for fuel separately?

The issue is that both GWCG & ZFWCG are incorrect if you adjust fuel in cruise, on a long-haul flight, ZFWCG is constantly moving as the aircraft burns off fuel, the init page and EICAS display the wrong information. If you double-tap the ZFWCG field in the init page whilst in flight, it updates the ZFWCG.

This can also cause issues on take off, as the wrong trim settings are provided if the aircraft load is changed. The only way to get the true GWCG is to use the OIS landing page, if you double-click the CG field, it reads it directly from the aircraft.

Jet-Pack (IPACS) · January 11, 2026 at 2:14 PM Official Post

Adjusting the fuel in the menu also causes the cargo and passengers to be redistributed again currently. The aircraft CG is balanced towards a set target when the fuel or payload are changed.

During flight the aircraft FMS currently doesn't really know the correct CG shift for the fuel so it uses the real time CG of the fuel instead. But the fuel moves around in the tank, that's why the displayed CG may change a bit depending on accelerations and flight attitude.

jcomm · January 11, 2026 at 3:29 PM

Quote from Jet-Pack (IPACS)

Adjusting the fuel in the menu also causes the cargo and passengers to be redistributed again currently. The aircraft CG is balanced towards a set target when the fuel or payload are changed.
During flight the aircraft FMS currently doesn't really know the correct CG shift for the fuel so it uses the real time CG of the fuel instead. But the fuel moves around in the tank, that's why the displayed CG may change a bit depending on accelerations and flight attitude.

Which, even with these limitations in the full implementation of systems, makes AEFS **UNIQUE** regarding aspects and details of the physics / aerodynamics model!

It's a great FLIGHT simulation, we just have to wait (patiently...) for the small team to continue to add their Magic to the upcoming builds !!!