What is A320 ZFWCG and how is it used in a simulator?

ZFWCG is the Airbus A320’s centre of gravity at zero fuel weight, expressed as a percentage of mean aerodynamic chord (MAC). In real-world operations and detailed flight simulators, obtain it from the completed payload load, then enter or confirm it with ZFW on the MCDU INIT B page before performance setup.

What does ZFWCG mean on an Airbus A320?

ZFWCG means zero fuel weight centre of gravity. It describes where the loaded aircraft balances when usable fuel is excluded, accounting for the aircraft, crew, passengers, baggage and cargo.

The value is normally expressed as %MAC, or percentage of mean aerodynamic chord. A larger percentage places the centre of gravity farther aft along the reference chord; it is not a percentage of the fuselage length or fuel capacity.

Payload location changes ZFWCG even when total weight remains identical. Our explanation of how simulators turn payload distribution into aircraft handling covers why moving passengers or cargo between stations affects pitch stability.

Where do you find the correct ZFWCG?

Use the ZFWCG calculated for the payload that is physically loaded into that specific simulated aircraft.

• Integrated EFB or load manager: This is normally the preferred source when it controls the add-on’s passenger and cargo stations. Complete the load, allow it to synchronise, and read the resulting ZFW and ZFWCG.
• Load sheet or flight-planning data: Use these figures only when the aircraft variant, cabin configuration and payload distribution match the simulator load exactly.
• Simulator weight-and-balance screen: Use its CG figure only if it explicitly identifies zero-fuel CG. A single CG value displayed after fuel has been loaded may be gross-weight CG or take-off CG instead.

Changing fuel alone must not change ZFW or ZFWCG because usable fuel is excluded from both. If the displayed CG moves as fuel is added, that display is probably showing the aircraft’s total CG rather than ZFWCG.

How do you enter ZFWCG in an A320 simulator?

Load the aircraft first, then transfer the matching ZFW and ZFWCG to the MCDU during pre-flight preparation. This task fits into the complete A320 cockpit-preparation order before take-off performance is finalised.

1. Select the correct aircraft: Confirm the exact A320 variant and cabin or add-on configuration. Do not reuse figures from an A319, A321 or differently configured A320.
2. Load the payload: Set passengers, baggage and cargo through the loading system that actually writes to the simulator’s payload stations. Avoid loading the aircraft once through the simulator and again through an add-on manager.
3. Check the envelope: Confirm that the zero-fuel and take-off loading points remain inside the permitted weight-and-balance envelope. Correct an out-of-envelope load by redistributing payload, not by typing a more convenient CG into the MCDU.
4. Open INIT B: Find the ZFW/ZFWCG field on the MCDU. For help locating it, see our overview of the A320 cockpit controls and MCDU layout.
5. Enter the paired values: Use the order and mass units shown by the aircraft. If the load manager reports an illustrative ZFW of 61.2 and ZFWCG of 27.4% MAC, the common entry format is 61.2/27.4. Do not treat those example numbers as a recommended load.
6. Verify fuel and gross weight: Enter or confirm block fuel separately. Before taxi, calculated gross weight should broadly correspond to ZFW plus fuel on board; take-off weight will be lower after taxi fuel is consumed.
7. Complete performance setup: Calculate take-off speeds, flap setting and stabiliser trim from the loaded aircraft’s performance data. ZFWCG is an input to the weight-and-balance picture, not a substitute for the take-off CG or trim result.

Some A320 simulations populate the field automatically after an EFB or loading-system synchronisation. Accept the automatic entry only after checking it against the same load source; changing payload later makes the previously entered figures stale.

Can you use a typical A320 ZFWCG value?

No universal A320 ZFWCG value is suitable for every flight. The correct figure depends on the aircraft configuration and where that flight’s passengers and cargo have been placed.

A value that looks plausible can still conceal an incorrect load. If a simplified simulator provides no separate ZFWCG readout, keep its payload stations within the displayed envelope and use the value it calculates or prefills rather than borrowing a number from another flight.

Why does the MCDU reject the ZFWCG entry?

Most rejected entries result from incorrect formatting, units or data copied from the wrong CG field.

• FORMAT ERROR: Check the order, decimal format and slash separator expected by that MCDU implementation. Enter ZFW first and ZFWCG second where the field is labelled ZFW/ZFWCG.
• ENTRY OUT OF RANGE: Confirm that ZFW uses the displayed mass unit and that the CG figure is %MAC. Some load sheets provide a separate loading index, which must not be entered as ZFWCG unless the loading tool converts it.
• MCDU and EFB disagree: Resynchronise the physical payload, then re-enter or refresh the MCDU data. Typing a different CG into the MCDU does not necessarily move passengers or cargo in the simulator’s flight model.
• The figures changed after loading: Check whether payload was altered after MCDU initialisation. Fuel changes gross weight and gross CG, but not ZFWCG.

Does ZFWCG affect take-off trim and rotation?

Yes, the aircraft’s real loaded CG affects trim and rotation, but the MCDU number alone may not alter the simulator’s physical balance. The payload stations determine the actual modelled CG; the entered ZFWCG tells the simulated flight-management system what loading condition to use for its calculations.

Take-off trim must be based on take-off CG, which includes the effect of loaded fuel, rather than blindly copying ZFWCG. An excessively forward physical CG or incorrect nose-up trim can make rotation difficult, while an aft CG reduces longitudinal stability. If the aircraft remains stuck to the runway, follow our checks for diagnosing an aircraft that will not rotate before changing the MCDU value.