Definition
The average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day, and prominent lighted objects may be seen and identified by night, when that vision is aided by an enhanced flight vision system (EFVS) that displays a sensor-derived or sensor-and-database image of the external scene to the pilot.
Plain English
It is how far ahead a pilot can clearly see and identify outside objects when using an onboard imaging system, such as an infrared camera, that shows a real-time picture of the world ahead. It replaces the pilot's natural eyesight as the basis for measuring visibility.
Context Anchor
Seen in low-visibility instrument approach rules and discussions of enhanced vision equipment.
Derivation
Enhanced means improved or boosted, from the Latin altus meaning high or raised. Here it signals that the pilot's normal forward visibility is being augmented by sensor technology rather than relying on the unaided eye.
Why Pilots Care
It permits descent below published minimums when the system provides a clear view of the runway, increasing access to airports in marginal weather.
Grounding Statement
Picture looking ahead on a dark, hazy approach and using an approved cockpit display to see runway lights or ground features farther ahead than your eyes alone can see.
Intuition Check
Enhanced flight visibility does not mean the weather has improved. It means the pilot’s usable view ahead is improved by an enhanced flight vision system.
Example Sentence 1
The captain confirmed the enhanced flight visibility on the EFVS display met the minimum required to continue the approach below decision altitude.
Example Sentence 2
Using the EFVS, the pilot determined that enhanced flight visibility was sufficient to land safely.