Compass Locator

A low power, low or medium frequency (L/MF) radio beacon installed at the site of the outer or middle marker of an instrument landing system (ILS). It can be used for navigation at distances of approximately 15 miles or as authorized in the approach procedure.
  1. Outer Compass Locator (LOM)- A compass locator installed at the site of the outer marker of an instrument landing system. (See OUTER MARKER.)
  2. Middle Compass Locator (LMM)- A compass locator installed at the site of the middle marker of an instrument landing system. (See MIDDLE MARKER.)

Source: FAA Pilot/Controller Glossary (definition from the 2023 edition; current: Change 1 of 7 August 2025).

Also listed as: Middle Compass Locator; Outer Compass Locator.

Related terms

Glossary last updated 2026-10-28.

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