Pilot/Controller Glossary 

4/20/23 

MISSED APPROACH SEGMENT

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(See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE.) 

MM

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(See MIDDLE MARKER.) 

MOA

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(See MILITARY OPERATIONS AREA.) 

MOCA

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(See MINIMUM OBSTRUCTION CLEARANCE ALTITUDE.) 

MODE

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 The letter or number assigned to a specific pulse spacing of radio signals transmitted or received by 

ground interrogator or airborne transponder components of the Air Traffic Control Radar Beacon System 

(ATCRBS). Mode A (military Mode 3) and Mode C (altitude reporting) are used in air traffic control. 

(See INTERROGATOR.) 
(See RADAR.) 
(See TRANSPONDER.) 
(See ICAO term MODE.) 
(Refer to AIM.) 

MODE (SSR MODE) [ICAO]

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 The letter or number assigned to a specific pulse spacing of the interrogation 

signals transmitted by an interrogator. There are 4 modes, A, B, C and D specified in Annex 10, corresponding 

to four different interrogation pulse spacings. 
MODE C INTRUDER ALERT

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 A function of certain air traffic control automated systems designed to alert 

radar controllers to existing or pending situations between a tracked target (known IFR or VFR aircraft) and an 

untracked target (unknown IFR or VFR aircraft) that requires immediate attention/action. 

(See CONFLICT ALERT.) 

MODEL AIRCRAFT

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 An unmanned aircraft that is: (1) capable of sustained flight in the atmosphere; (2) flown 

within visual line of sight of the person operating the aircraft; and (3) flown for hobby or recreational purposes

. 

MONITOR

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(When used with communication transfer) listen on a specific frequency and stand by for 

instructions. Under normal circumstances do not establish communications. 
MONITOR ALERT (MA)

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 A function of the TFMS that provides traffic management personnel with a tool for 

predicting potential capacity problems in individual operational sectors. The MA is an indication that traffic 

management personnel need to analyze a particular sector for actual activity and to determine the required 

action(s), if any, needed to control the demand. 
MONITOR ALERT PARAMETER (MAP)

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 The number designated for use in monitor alert processing by the 

TFMS. The MAP is designated for each operational sector for increments of 15 minutes. 
MOSAIC/MULTI

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SENSOR MODE

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Accepts positional data from multiple approved surveillance sources. 

Targets are displayed from a single source according to the hierarchy of the sources assigned in a given 

geographic area. 
MOUNTAIN WAVE– Mountain waves occur when air is being blown over a mountain range or even the ridge 

of a sharp bluff area. As the air hits the upwind side of the range, it starts to climb, thus creating what is generally 

a smooth updraft which turns into a turbulent downdraft as the air passes the crest of the ridge. Mountain waves 

can cause significant fluctuations in airspeed and altitude with or without associated turbulence. 

(Refer to AIM.) 

MOVEMENT AREA

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 The runways, taxiways, and other areas of an airport/heliport which are utilized for 

taxiing/hover taxiing, air taxiing, takeoff, and landing of aircraft, exclusive of loading ramps and parking areas. 

At those airports/heliports with a tower, specific approval for entry onto the movement area must be obtained 

from ATC. 

(See ICAO term MOVEMENT AREA.) 

PCG M

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