4/20/23 

Pilot/Controller Glossary 

R 

RAD

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(See ROUTE AMENDMENT DIALOG.) 

RADAR

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 A device that provides information on range, azimuth, and/or elevation of objects by measuring the 

time interval between transmission and reception of directional radio pulses and correlating the angular 

orientation of the radiated antenna beam or beams in azimuth and/or elevation

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a. 

Primary Radar

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 A radar system in which a minute portion of a radio pulse transmitted from a site is reflected 

by an object and then received back at that site for processing and display at an air traffic control facility. 

b. 

Secondary Radar/Radar Beacon (ATCRBS)

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 A radar system in which the object to be detected is fitted 

with cooperative equipment in the form of a radio receiver/transmitter (transponder). Radar pulses transmitted 

from the searching transmitter/receiver (interrogator) site are received in the cooperative equipment and used 

to trigger a distinctive transmission from the transponder. This reply transmission, rather than a reflected signal, 

is then received back at the transmitter/receiver site for processing and display at an air traffic control facility. 

(See COOPERATIVE SURVEILLANCE.) 
(See INTERROGATOR.) 
(See NON

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COOPERATIVE SURVEILLANCE.) 

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

RADAR [ICAO]

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 A radio detection device which provides information on range, azimuth and/or elevation of 

objects. 

a. 

Primary Radar

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 Radar system which uses reflected radio signals. 

b. 

Secondary Radar

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 Radar system wherein a radio signal transmitted from a radar station initiates the 

transmission of a radio signal from another station. 
RADAR ADVISORY

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 The provision of advice and information based on radar observations. 

(See ADVISORY SERVICE.) 

RADAR ALTIMETER

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(See RADIO ALTIMETER.) 

RADAR APPROACH

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 An instrument approach procedure which utilizes Precision Approach Radar (PAR) or 

Airport Surveillance Radar (ASR). 

(See AIRPORT SURVEILLANCE RADAR.) 
(See INSTRUMENT APPROACH PROCEDURE.) 
(See PRECISION APPROACH RADAR.) 
(See SURVEILLANCE APPROACH.) 
(See ICAO term RADAR APPROACH.) 
(Refer to AIM.) 

RADAR APPROACH [ICAO]

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 An approach, executed by an aircraft, under the direction of a radar controller. 

RADAR APPROACH CONTROL FACILITY

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 A terminal ATC facility that uses radar and nonradar 

capabilities to provide approach control services to aircraft arriving, departing, or transiting airspace controlled 

by the facility. 

(See APPROACH CONTROL SERVICE.) 

a. 

Provides radar ATC services to aircraft operating in the vicinity of one or more civil and/or military airports 

in a terminal area. The facility may provide services of a ground controlled approach (GCA); i.e., ASR and PAR 

approaches. A radar approach control facility may be operated by FAA, USAF, US Army, USN, USMC, or 

PCG R

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