This glossary is written for virtual airline and flight simulation use within Virtual Air Canada Airline. It is not intended as a real-world aviation reference.
VMC
Visual Meteorological Conditions
VMC describes weather conditions that meet or exceed the minimum visibility, cloud ceiling, and cloud clearance thresholds required for flight under Visual Flight Rules (VFR). The specific minima vary by airspace class, altitude, and jurisdiction, but the general requirement is that pilots can see and avoid other aircraft and terrain by visual reference. In uncontrolled airspace below 10,000 feet, ICAO basic VFR minima require a flight visibility of at least 5 km and cloud clearance of 1,500 metres horizontally and 300 metres (1,000 feet) vertically. In controlled airspace and at higher altitudes, the minima are more demanding.
When conditions deteriorate below the applicable VMC minima, the airspace is said to be in Instrument Meteorological Conditions (IMC), and only pilots rated and current for Instrument Flight Rules (IFR) may legally operate. Commercial air transport operations routinely operate in IMC and are planned, equipped, and crewed for IFR flight. Understanding the distinction between VMC and IMC is fundamental to flight planning and dispatch decision-making. Visual approaches are conducted in VMC, and many approach minimums - such as circling approaches - have VMC requirements built into their criteria. The “visual” in VMC means the pilot has the visual references needed to control the aircraft and comply with airspace requirements without sole reliance on instruments.