---
title: "MIDDLE MARKER — aviation glossary — OnlyPlanes"
description: "A marker beacon that defines a point along the glideslope of an ILS normally located at or near the point of decision height (ILS Category I)."
canonical_url: "https://onlyplanes.ru/en/learn/middle-marker"
locale: en
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  "og:image": "https://onlyplanes.ru/images/aviation/aircraft/boeing-787.webp"
  "og:title": "MIDDLE MARKER — aviation glossary"
---

> Index of every page on this site: [llms.txt](https://onlyplanes.ru/llms.txt)

Operations

# MIDDLE MARKER

MM

TERM · Operations

At a glance

## Meaning of MIDDLE MARKER

A marker beacon that defines a point along the glideslope of an ILS normally located at or near the point of decision height (ILS Category I).

### More about MIDDLE MARKER

A marker beacon that defines a point along the glideslope of an ILS normally located at or near the point of decision height (ILS Category I). It is keyed to transmit alternate dots and dashes, with the alternate dots and dashes keyed at the rate of 95 dot/dash combinations per minute on a 1300 Hz tone, which is received aurally and visually by compatible airborne equipment.

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