Glideslope (GS)


Part of the ILS that projects a radio beam upward at an angle of approximately 3° from the approach end of an instrument runway. The glideslope provides vertical guidance to aircraft on the final approach course for the aircraft to follow when making an ILS approach along the localizer path.

Source: Pilot's Handbook of Aeronautical Knowledge (definition from the FAA-H-8083-25B, 2016; current: FAA-H-8083-25C, 2023, with the October 2025 addendum).

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Glossary last updated 2026-10-28.