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AIM

10/12/17

4−5−21

Surveillance Systems

4−5−10. Automatic Dependent

Surveillance−Rebroadcast (ADS−R)

a. Introduction.

ADS−R is a datalink translation function of the

ADS−B ground system required to accommodate the

two separate operating frequencies (978 MHz and

1090 ES). The ADS−B system receives the ADS−B

messages transmitted on one frequency and ADS−R

translates and reformats the information for

rebroadcast and use on the other frequency. This

allows ADS−B In equipped aircraft to see nearby

ADS−B Out traffic regardless of the operating link of

the other aircraft. Aircraft operating on the same

ADS−B frequency exchange information directly

and do not require the ADS−R translation function.

(See FIG 4−5−8 and FIG 4−5−9.)

b. Reports of ADS−R Malfunctions.

Users of ADS−R can provide valuable assistance in

the correction of malfunctions by reporting instances

of undesirable system performance. Since ADS−R

performance is monitored by maintenance personnel

rather than ATC, report malfunctions to the nearest

Flight Service Station (FSS) facility by radio or

telephone. Reporters should identify:

1. Condition observed.
2. Date and time of observation.
3. Altitude and location of observation.
4. Type and call sign of the aircraft.
5. Type and software version of avionics

system.