Plain English Meaning

A ground-based radio system that gives the pilot two electronic 'beams' to follow during landing — one to keep the aircraft lined up with the runway, and another to keep it on the correct descending path to the touchdown point. It lets pilots land safely when they can't see the runway until the last moments.

Full Definition

A precision approach navigation system that provides pilots with electronic guidance both horizontally (left/right of the runway centerline) and vertically (above/below the correct descent path) to a specific runway, allowing landings in low-visibility conditions. An ILS typically consists of a for lateral guidance, a for , and lighting and or for distance information.