Definition
A precision approach navigation system that provides pilots with horizontal (lateral) and vertical guidance to a specific runway, allowing approach and landing in low visibility or low ceiling conditions. It typically consists of a localizer for runway centerline alignment, a glideslope for descent angle guidance, and marker beacons or distance measuring equipment for position information along the approach.
Plain English
A ground-based radio system that gives a pilot two guidance signals during the final approach: one telling them if they are left or right of the runway centerline, and another telling them if they are above or below the correct descent path. Together, these guide the aircraft down to the runway when the pilot can't see it clearly.
Context Anchor
Pilots encounter ILS in instrument training, approach clearances, and approach charts for airports that have ILS equipment serving a runway.
Why Pilots Care
Enables safe landings when visibility is too low for visual approaches, directly supporting schedule reliability and safety margins.
Intuition Check
ILS is guidance, not an automatic landing by itself. The pilot or autopilot still has to follow the guidance correctly and meet all required conditions for the approach.
Example Sentence 1
The pilot tuned the ILS frequency, identified the localizer, and began the approach to runway 27.
Example Sentence 2
During the checkride the examiner requested an ILS approach to the lowest authorized minimums.