What does gross weight refer to in aviation?

Gross weight in aviation refers to the total weight of the aircraft when it is fully loaded. This includes not only the empty weight of the aircraft itself but also the weight of all contents such as passengers, cargo, and any mounted items. Understanding gross weight is crucial for pilots and crews, as it impacts performance calculations, fuel requirements, and load limits. Proper management of gross weight ensures safety during flight operations by adhering to the aircraft's structural limits and performance capabilities.

The other options focus on more specific elements of weight measurement. For instance, the weight of the aircraft without fuel would only consider the airframe and its basic equipment, while the weight noted during flight does not reflect ground conditions or total loading. Similarly, excluding external items does not provide an accurate picture of the aircraft's operational weight when determining safety and efficiency. Thus, option B accurately captures the comprehensive measure of gross weight in the context of aviation.