Which of the following represents the weight of an aircraft with only permanently installed equipment?

The correct answer is the weight of the aircraft with only permanently installed equipment, which is referred to as Empty Weight. This weight includes the airframe, engines, all permanently installed equipment, and unusable fuel and oil, but excludes any payload or usable fuel. This term is crucial in aviation because it serves as a baseline for understanding an aircraft's operational capabilities and limitations.

By knowing the Empty Weight, pilots and operators can calculate other important weight measures, such as the Takeoff Weight and Gross Weight, which incorporate additional loads like cargo, passengers, and fuel. Understanding these distinctions helps ensure safe operations and compliance with regulations regarding weight limitations.