Plain English Meaning

Landings made by following two radio beams from the airport — one that keeps you lined up with the runway and one that keeps you on the correct descent angle — so you can land safely even when you cannot see the runway until close in.

Full Definition

Landings conducted using the Instrument Landing System, a ground-based precision approach aid that transmits two radio signals — a localizer for lateral (left/right) guidance to the runway centerline and a glideslope for vertical (up/down) guidance to the touchdown zone. The pilot follows these signals, displayed on cockpit instruments, to descend along a precise path to the runway, often in low-visibility conditions.