AIM Text
- 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 4-5-7 and FIG 4-5-8.)
- 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, or by sending an email to the ADS-B help desk at adsb@faa.gov. Reports should include:
- Condition observed;
- Date and time of observation;
- Altitude and location of observation;
- Type and call sign of the aircraft and;
- Type and software version of avionics system.
Source: FAA Aeronautical Information Manual · current edition · paragraph 4-5-10.
The short answer
This AIM section is FAA advisory guidance on Automatic Dependent Surveillance-Rebroadcast (ADS-R), a datalink translation function of the ADS-B ground system. It bridges the two ADS-B frequencies (978 MHz and 1090 ES) so ADS-B In equipped aircraft can see nearby ADS-B Out traffic regardless of the other aircraft's link, supporting ADS-B operations under 14 CFR 91.225/91.227.
Research Notes
Common Questions
What does ADS-R actually do and why is it needed?
The AIM explains ADS-R is a datalink translation function of the ADS-B ground system that accommodates the two separate operating frequencies, 978 MHz and 1090 ES. The ground system receives ADS-B messages on one frequency and ADS-R translates and reformats them for rebroadcast on the other, letting ADS-B In aircraft see nearby ADS-B Out traffic regardless of the other aircraft's link.
Do two aircraft on the same ADS-B frequency need ADS-R?
No. According to the AIM, aircraft operating on the same ADS-B frequency exchange information directly and do not require the ADS-R translation function. ADS-R is only needed to bridge traffic operating on the opposite link (978 MHz versus 1090 ES).
How do I report an ADS-R malfunction?
Because ADS-R performance is monitored by maintenance personnel rather than ATC, the AIM directs users to report malfunctions to the nearest Flight Service Station (FSS) by radio or telephone, or by email to the ADS-B help desk at adsb@faa.gov. Reports should include the condition observed; date and time; altitude and location; aircraft type and call sign; and avionics type and software version.