In ATC, what does 'VFR' stand for?

In air traffic control (ATC), 'VFR' stands for Visual Flight Rules. This term refers to the regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Under VFR, pilots navigate by visual reference to the ground and maintain separation from other aircraft without the use of instruments.

VFR is critical for pilots, as it allows them to fly without relying solely on navigational instruments. It implies that the flight conditions are suitable for visual navigation, which enhances pilot situational awareness. This concept is vital for pilots to understand, as it delineates when VFR flight is permissible and the responsibilities that come with operating under these rules.

The other options do not reflect established aviation terminology. For instance, "Very Flight Readiness" and "Variable Flight Route" do not correspond to recognized rules or terms in aviation. "Virtual Flight Regulations" is also not a standard term used in ATC or among pilots. Thus, the correct and relevant interpretation of VFR is indeed Visual Flight Rules.