When determining the empty weight of an aircraft, what is considered a part of the empty weight according to current airworthiness standards?

When determining the empty weight of an aircraft, the empty weight is defined as the weight of the aircraft without any payload or usable fuel but typically includes other essential fluids. One of these fluids is the oil in the supply tank, which is considered necessary for the operation of the aircraft's systems.

In aviation, empty weight encompasses the airframe, the installed engines, and all items required for the aircraft's operation, including instruments, batteries, and necessary fluids such as oil. This is critical for accurate weight and balance calculations as part of airworthiness standards, which ensure safety and performance during flight.

In contrast, fluids like fuel are not included in the empty weight as they are considered variable loads. Additionally, passenger and cargo weights are also excluded from the empty weight calculation because they represent the load carried on board during flight rather than the inherent weight of the aircraft itself.