What does the total mass of usable fuel, crew, passengers, baggage, and freight represent?

The total mass of usable fuel, crew, passengers, baggage, and freight is referred to as the Traffic Load. This term encompasses all the weight that contributes to the aircraft's operational efficiency and capability. It primarily includes anything that affects the aircraft’s performance during flight, such as the additional mass from passengers, cargo, and fuel that is necessary for the flight.

The concept of Traffic Load is crucial for mass and balance calculations, as it helps ensure the aircraft remains within its specified limits for safe operation. Understanding this mass is essential for flight planning to ensure that the aircraft can take off, climb, cruise, and land safely, all while adhering to weight requirements.

In contrast, terms like Dry Operating Mass or Zero Fuel Mass represent different aspects of an aircraft's weight. Dry Operating Mass includes the weight of the aircraft with all operating fluids except usable fuel, while Zero Fuel Mass includes everything except the fuel, which would therefore not account for usable fuel. Basic Empty Mass refers to the aircraft without any payload or usable fuel, strictly focused on the structure and essential systems.