Definition
The lowest altitude, expressed in feet above mean sea level, to which an air traffic controller may vector an aircraft under radar control, except as otherwise authorized for radar approaches, departures, and missed approaches. MVAs provide at least 1,000 feet of obstacle clearance (2,000 feet in designated mountainous terrain) and are depicted on controller charts in defined sectors around the radar facility. They are not generally published for pilots, so the pilot relies on the controller to issue safe vectoring altitudes.
Plain English
The lowest altitude a controller is allowed to send you down to when steering you with headings on radar. It is set high enough to keep you safely above terrain and obstacles in that area.
Context Anchor
You will see MVAs discussed in instrument flying, especially when air traffic control is giving radar vectors near terrain, obstacles, or airports.
Derivation
Vectoring comes from the Latin vector, meaning 'one who carries or conveys,' later used in mathematics for a quantity with direction. In ATC, a vector is a heading the controller assigns to guide the aircraft along a chosen path. The Minimum Vectoring Altitude is therefore the lowest altitude at which the controller is permitted to do that guiding.
Why Pilots Care
MVAs protect against terrain and obstacle collisions when pilots are being vectored by controllers instead of flying published routes.
Analogy
Think of an MVA like a minimum safe floor drawn on the controller’s map. The controller can guide you around above that floor, but normally cannot take you below it.
Grounding Statement
When a controller says to fly a heading, the MVA helps ensure that heading does not put the aircraft too low for the area it is crossing.
Intuition Check
Minimum does not mean the lowest altitude the airplane can physically fly. Here it means the lowest altitude air traffic control is allowed to use for radar vectoring in that area.
Example Sentence 1
Approach told us to expect vectors to the final approach course but kept us at 4,000 feet because that was the MVA in our sector.
Example Sentence 2
We remained at or above the published MVA until ATC assigned a lower altitude on the approach.