What does "zero fuel weight" indicate?

Zero fuel weight (ZFW) refers to the total weight of the aircraft when it is completely loaded with passengers, cargo, and any other items, but excluding any usable fuel. This measurement is critical for determining the aircraft's loading limits and ensuring that it operates within safe structural limits, as the aircraft's design considerations account for the weight of the structure and payload but not the fuel.

Understanding zero fuel weight helps pilots assess if the aircraft can still carry the necessary amount of fuel for a flight without exceeding weight limits for takeoff, landing, and in-flight operations. It serves as a baseline for calculating various operational parameters, including the maximum takeoff weight and the weight of the usable fuel the aircraft can safely carry.