Definition
On an Emergency Obstruction Video Map (EOVM), a charted reference value showing the elevation of terrain or obstacles that lie below the standard minimum vectoring altitude in a given sector. It is provided to give controllers and pilots a usable altitude reference during an emergency, when descent below the normal MVA may be necessary.
Plain English
A number on an emergency map that tells you how high the ground or tall objects are in a particular area, so that in an emergency you know how low it is safe to go.
Context Anchor
Seen when interpreting an Emergency Obstruction Video Map during an emergency or low-visibility situation where terrain and obstacles are being displayed for awareness.
Derivation
Elevation comes from a Latin idea meaning “to raise up.” In aviation, elevation points to how high something is measured from a fixed reference, commonly average sea level, which helps separate it from simple height above the ground.
Why Pilots Care
Gives the pilot or controller the floor reference needed to choose a safe emergency altitude that clears all obstacles and terrain in the sector.
Grounding Statement
On the display, lower terrain or obstacles are the features that sit below the higher features being highlighted or compared.
Intuition Check
Do not read “lower” as “safe.” Here it means lower in elevation compared with other terrain or obstacles on the display, not guaranteed obstacle-free flight path.
Example Sentence 1
During the emergency descent, the controller referenced the lower terrain/obstacle elevation on the EOVM before clearing the aircraft below the published MVA.
Example Sentence 2
Reviewing the lower terrain/obstacle elevation confirmed the aircraft could level off at 2,800 feet without risk.