Plain English Meaning

A simple set of two light bars next to the runway that tells the pilot, by their colors, whether they are coming in too high, too low, or just right.

Full Definition

A Visual Approach Slope Indicator system using two rows of light units, called the near bar and the far bar, positioned beside the runway to show whether an aircraft is on, above, or below the correct approach path. When both bars appear white the aircraft is above the glide path, both red means below the glide path, and red over white indicates on the glide path.

Context Anchor

Seen during the visual part of an approach to a runway, especially when checking whether the is on a for .