Aviation glossary
VMC
Visual Meteorological Conditions — the visibility and cloud-clearance minima that must be met for a VFR flight.
VMC (Visual Meteorological Conditions) defines the minimum visibility and distance from cloud required for VFR flight. The exact values depend on airspace class and altitude (in the Czech Republic typically 5 km / 1500 m horizontally / 300 m vertically from cloud in Class C, with exceptions below FL 100 and above 3000 ft AGL). SERA (Standardised European Rules of the Air) has the full detail. When conditions fall below VMC the flight is in IMC.
Related terms
- IMCInstrument Meteorological Conditions — weather that does not meet VMC. Flight is only possible under IFR with the appropriate rating.
- VFRVisual Flight Rules — the pilot navigates by outside visual reference and must meet VMC minima.
- Marginal VMCMarginal visual meteorological conditions — weather that still meets VFR minima, but with very little margin. Demands heightened attention and an escape plan.
- CAVOKCeiling And Visibility OK — visibility ≥ 10 km, no significant cloud below 5000 ft (or MSA), no significant weather.