Zero-fuel weight
The previous formula becomes: For many types of airplane, the airworthiness limitations include a maximum zero-fuel weight.The maximum zero fuel weight (MZFW) is the maximum weight allowed before usable fuel and other specified usable agents (engine injection fluid, and other consumable propulsion agents) are loaded in defined sections of the aircraft as limited by strength and airworthiness requirements.The addition of usable and consumable items to the zero fuel weight must be in accordance with the applicable government regulations so that airplane structure and airworthiness requirements are not exceeded.When an aircraft is being loaded with crew, passengers, baggage and freight it is most important to ensure that the ZFW does not exceed the MZFW.Designers of airplanes can optimise the maximum takeoff weight and prevent overloading in the fuselage by specifying a MZFW.