Plain English Meaning

Lights set into the runway surface itself — not on poles or beside the runway — that help pilots see where they are on the runway when visibility is poor.

Full Definition

Lights installed flush with the runway surface to provide visual guidance to pilots during takeoff, landing, and rollout in low-visibility conditions. In-runway lighting includes runway centerline lights, touchdown zone lights, taxiway turnoff lights, and runway remaining indicators, each using specific colors and spacing to convey position information along the runway.

Context Anchor

Seen in airport lighting descriptions, night operations, low-visibility operations, and runway or .