According to 14 CFR part 1, what does VF stand for?

The correct answer is that VF stands for Design flap speed. This terminology is used within the context of aircraft performance standards as specified in the regulations. Design flap speed is the maximum speed at which the flaps can be safely deployed without risking damage to the aircraft or affecting its performance. It provides a benchmark for pilots to understand the limits regarding flap operations, ensuring safe and effective handling of the aircraft during various phases of flight, especially during approach and landing.

While other terms mentioned, such as maximum flap extended speed or critical flap speed, may refer to specific operational limits, they do not specifically define the design characteristics as laid out under CFR regulations. Understanding the precise definitions is crucial for pilots and aviation professionals when considering operational procedures and safety protocols.