What defines the flight envelope of an aircraft?

The flight envelope of an aircraft is defined by the boundary of operational altitude and airspeed. This concept outlines the safe and optimal operating parameters within which the aircraft can be flown, ensuring the aircraft remains within its design limitations for various flight conditions.

Understanding the flight envelope is crucial for pilots, as it informs them about the performance capabilities of the aircraft under different conditions, including changes in weight, configuration, and environmental factors. Operating outside of this envelope could lead to loss of control or other dangerous situations.

The other aspects mentioned, such as maximum weight, fuel efficiency, and geographic boundaries, are important for overall flight planning and operational safety, but they do not specifically define the flight envelope itself. Rather, they are factors that can influence or affect the parameters that establish the envelope.