There are two sets of NAS flight rules; what are they?

• A. VFR and IFR
• B. VFR and VOR
• C. Day and Night
• D. IFR and VFR

Answer: (A)

The main idea is that the National Airspace System uses two flight-rule categories: Visual Flight Rules and Instrument Flight Rules. Visual Flight Rules are when you fly primarily by looking outside, staying clear of clouds, and keeping a sufficient line-of-sight to see and avoid other aircraft. Instrument Flight Rules are when you rely on cockpit instruments and navigational systems, following ATC clearances and published procedures to maintain separation when visibility or cloud conditions are insufficient for visual operation. The other options don’t describe the two rule sets: a VOR is a navigation aid, Day/Night are operating conditions, and IFR and VFR are just the same two categories listed in a different order.