middle marker

middle marker (plural middle markers)

1. (aviation) A type of marker beacon placed to indicate the missed approach point of a Category I ILS or IGS approach (typically the point at which the glideslope descends through 200 feet AGL), triggering a continuous visual and aural sequence of alternating Morse code dots and dashes from the marker beacon receiver in the cockpit of an aircraft flying over the marker.

• MM

• marker beacon

• fan marker
• inner marker
• outer marker