MZFW

Maximum Zero Fuel Weight (MZFW) is the maximum allowable weight of an aircraft when it carries no usable fuel aboard. It is a structural limit established during certification to ensure that airframe stresses, particularly on the wings, and the distribution of weight remain within design boundaries when payload and non-fuel items are on board but fuel is not yet added.

In practical terms, the actual zero-fuel weight (the aircraft’s weight excluding usable fuel) must not exceed the MZFW. The total aircraft weight for a flight, however, is still limited by the Maximum Takeoff Weight (MTOW), which includes fuel. This separation allows payload and other non-fuel items to be carried up to the MZFW, while additional weight from fuel is added later up to the MTOW for the flight.

If the payload required for a mission would push the zero-fuel weight above the published MZFW, the flight cannot be conducted with that payload in that configuration. Operators must offload payload, reconfigure the aircraft, or choose a different aircraft or flight plan.

MZFW values are aircraft-specific and published in the Aircraft Flight Manual or Operator Manual for each variant. They vary by model and configuration, reflecting the structural design limits for safe operation under typical loading conditions.