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12/2/21 

Pilot/Controller Glossary 

MISSED APPROACH SEGMENT

 

(See SEGMENTS OF AN INSTRUMENT 

APPROACH PROCEDURE.) 

MM

 

(See MIDDLE MARKER.) 

MOA

 

(See MILITARY OPERATIONS AREA.) 

MOCA

 

(See MINIMUM OBSTRUCTION CLEARANCE 

ALTITUDE.) 

MODE

 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]

 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

 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/ac­
tion. 

(See CONFLICT ALERT.) 

MODEL AIRCRAFT

 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

 (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)

 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)

 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

SENSOR MODE

 Accepts posi­

tional data from multiple radar or ADS

B sites. 

Targets are displayed from a single source within a 
radar sort box according to the hierarchy of the 
sources assigned. 

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

 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.) 

MOVEMENT AREA [ICAO]

 That part of an 

aerodrome to be used for the takeoff, landing and 
taxiing of aircraft, consisting of the maneuvering area 
and the apron(s). 

MOVING TARGET INDICATOR

 An electronic 

device which will permit radar scope presentation 
only from targets which are in motion. A partial 
remedy for ground clutter. 

MRA

 

(See MINIMUM RECEPTION ALTITUDE.) 

MRE

 

(See METER REFERENCE ELEMENT.) 

PCG M