VFR
Visual Flight Rules require the pilot to see and avoid other traffic and terrain, with minimum visibility and cloud clearance that vary by airspace class and altitude.
IFR
Instrument Flight Rules allow flight in cloud with ATC providing separation. It requires an instrument rating, a suitably equipped aircraft and a filed flight plan.
Special cases
Special VFR permits limited operations below normal VFR minima with ATC approval. Airline transport is essentially always IFR, regardless of how good the weather is.
Key points
- VFR: see and avoid. IFR: ATC separation and instrument procedures.
- Airline flights operate IFR even in clear weather.
- VMC/IMC describe the conditions; VFR/IFR describe the rules being flown.
Knowledge check