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AIM

4/20/23

4

5

19

Surveillance Systems

MHz transponders with integrated ADS

B functionality extend the transponder message sets with additional

ADS

B information. This additional information is known as an “extended squitter” message and is referred to

as 1090ES. ADS

B equipment operating on 978 MHz is known as the Universal Access Transceiver (UAT).

3.

ADS

B avionics can have the ability to both transmit and receive information. The transmission of

ADS

B information from an aircraft is known as ADS

B Out. The receipt of ADS

B information by an aircraft

is known as ADS

B In. All aircraft operating within the airspace defined in 14 CFR § 91.225 are required to

transmit the information defined in § 91.227 using ADS

B Out avionics.

4.

In general, operators flying at 18,000 feet and above (Class A airspace) are required to have 1090ES

equipment. Those that do not fly above 18,000 may use either UAT or 1090ES equipment. (Refer to 14 CFR

 

§§

91.225 and 91.227.) While the regulations do not require it, operators equipped with ADS

B In will realize

additional benefits from ADS

B broadcast services: Traffic Information Service – Broadcast (TIS

B)

(paragraph 4

5

8) and Flight Information Service 

 Broadcast (FIS

B) (paragraph 4

5

9).

FIG 4

5

8

ADS

B, TIS

B, and FIS

B:

Broadcast Services Architecture

b. ADS

B Certification and Performance Requirements.

ADS

B equipment may be certified as a surveillance source for air traffic separation services using ADS

B Out.

ADS

B equipment may also be certified for use with ADS

B In advisory services that enable appropriately

equipped aircraft to display traffic and flight information. Refer to the aircraft’s flight manual supplement or Pilot
Operating Handbook for the capabilities of a specific aircraft installation.

c. ADS

B Capabilities and Procedures.

1.

ADS

B enables improved surveillance services, both air

to

air and air

to

ground, especially in areas

where radar is ineffective due to terrain or where it is impractical or cost prohibitive. Initial NAS applications