(2)
Elevation Station.

(3) Precision Distance Measuring Equipment (See Microwave Landing System Categories).

MIDDLE COMPASS LOCATOR - (See Compass Locator)
MIDDLE MARKER/MM - A marker beacon that defines a point along the glide slope of an Instrument Landing System normally located at or near the point of Decision Height (Instrument Landing System 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 Hertz tone, which is received aurally and visually by compatible airborne equipment. (See Marker Beacon, Instrument Landing System)
MID RVR - (See Visibility)
MIJI - Meaconing, Intrusion, Jamming, and Interference.
MILES-IN-TRAIL - A specified distance between aircraft, normally, in the same stratum associated with the same destination or route of flight.
MILITARY AUTHORITY ASSUMES RESPONSIBILITY FOR SEPARATION OF AIRCRAFT/MARSA - A condition whereby the military services involved assume responsibility for separation between participating military aircraft in the Air Traffic Control system. It is used only for required Instrument Flight Rules operations which are specified in letters of agreement or other appropriate Federal Aviation Administration or military documents.
MILITARY OPERATIONS AREA/MOA - (See Special Use Airspace)
MILITARY TRAINING ROUTES/MTR - Airspace of defined vertical and lateral dimensions established for the conduct of military flight training at airspeeds in excess of 250 knots indicated airspeed. (See Instrument Flight Rules (IR) and Visual Flight Rules (VR) Military Training Routes)