VMC
Visual Meteorological Conditions / Minimum Control Speed
Two meanings: visual weather conditions (VFR), or the minimum control speed with one engine inoperative.
VMC has two distinct meanings in aviation and the context determines which is intended.
**As a weather term:** Visual Meteorological Conditions are weather at or above the minimums required for visual flight rules per FAR 91.155. The opposite of IMC.
**As a multi-engine performance term:** V-sub-Mc (VMC) is the minimum control speed with the critical engine inoperative. Below VMC, full rudder deflection cannot maintain directional control with the operating engine at full power. The placard value (the red line) is determined under specific certification conditions; actual VMC varies with altitude, weight, configuration, and bank angle.
For multi-engine pilots, VMC is the more frequently-referenced meaning. For all other pilots, the weather meaning is more common.
When it matters
Multi-engine students demonstrate V<sub>MC</sub> on the practical test. Understanding what moves actual V<sub>MC</sub> (altitude, weight, bank angle) is central to multi-engine training.
In Aloft360
Multi-engine training guide