Plain English Meaning
A planned way of moving your eyes across the sky in small steps so you actually see things that are out there, instead of just staring straight ahead and hoping to spot them.
Full Definition
A systematic technique for visually searching the sky outside the aircraft to detect other traffic, terrain, weather, and obstacles, using a series of short, regularly spaced eye movements that bring successive areas of the sky into the central field of vision.
Context Anchor
Used in collision avoidance, especially before turns, during climb and descent, near airports, and any time the pilot is responsible for watching outside the aircraft.