Updated March 28, 2019
Automatic Dependent Surveillance-Broadcast (ADS-B), a satellite-based aircraft monitoring system, will replace the cornerstone technology for monitoring aircraft in the skies and on the ground in the continuing transformation to a Next Generation (“NextGen”) aviation system.
ADS-B uses the aircraft’s global positioning system (GPS) for position information and transmits its position along with several other data fields including aircraft type, speed, flight number, and whether the aircraft is turning, climbing or descending, which are not transmitted by today’s radar technology. This information is sent to air traffic control (ATC), as well as other aircraft. ADS-B updates an aircraft’s position to ATC once per second, while radar updates ATC once every 3 to 12 seconds. Aircraft equipped with ADS-B that transmit these data field have what is called ADS-B Out.
An aircraft has the next level of equipage, called ADS-B In, when the aircraft not only sends the ADS-B Out data, but will also receive the data sent from other aircraft and ATC. This allows the pilot to see heading, altitude, speed, aircraft category, call sign, and distance on other aircraft that are ADS-B Out equipped. The aircraft will also be able to access to ATC data of position reports from secondary surveillance sources for non-ADS-B equipped aircraft.
With the appropriate displays, an aircraft can use the ADS-B In data to provide a graphical representation of other traffic around you. This is called Traffic Information Service-Broadcast (TIS-B). While Traffic Alert and Collision Avoidance System (TCAS) currently provides this information, TIS-B will give more information, making the TCAS display more accurate. TCAS will continue to detect and issue Traffic Alerts and Resolution Advisories that ADS-B will not.
In addition to TIS-B data, ADS-B In equipped aircraft can also receive Flight Information Service-Broadcast (FIS-B) data which allows the flight crew to see and read information such as METARs, TAFs, and NEXRAD radar. All of these are to be provided free without a subscription requirement.
In the U.S., ADS-B equipment can use either 1090 MHz Extended Squitters (1090ES) or Universal Access Transceivers (UAT) at 978 MHz. The UAT may be less expensive, but when operating at or above FL240, 1090ES will be mandatory. Outside of the U.S., and for the near future, Air Navigation Service Providers are planning to use 1090ES and not UAT, so operators should factor that into equipment purchasing decisions.
Automatic Dependent Surveillance-Contract (ADS-C) is similar to ADS-B, but when the aircraft logs on to the Air Navigation Service Provider (ANSP) the aircraft sets up a “Contract” with ATC. ADS-C is a Datalink system used primarily for making position reports.The Datalink system also allows operators to request and receive their oceanic clearances. However, ADS-C is separate from Controller/Pilot Data Link (CPDLC). While ADS-C can function CPDLC, CPDLC cannot function without ADS-C. These two technologies combined provide the basis for FANS compatibility.
U.S. ADS-B Implementation
On October 5, 2007, the FAA published a Notice of Proposed Rulemaking (NPRM) seeking comments on proposed avionics equipment and performance requirements for aircraft in specified airspace. An ADS-B Aviation Rulemaking Committee (ARC), co-chaired by NBAA, followed shortly after. The ARC was established by the FAA Administrator under FAA Order 1110.147 to provide a forum for the U.S. aviation community to discuss and review the NPRM for ADS-B, formulate recommendations on presenting and structuring an ADS-B mandate and consider additional actions that will be necessary to implement those recommendations. Review the full Notice of Proposed Rulemaking (NPRM) seeking comments on proposed avionics equipment and performance requirements for aircraft in specified airspace. An ADS-B Aviation Rulemaking Committee (ARC), co-chaired by NBAA, followed shortly after. The ARC was established by the FAA Administrator under FAA Order 1110.147 to provide a forum for the U.S. aviation community to discuss and review the NPRM for ADS-B, formulate recommendations on presenting and structuring an ADS-B mandate and consider additional actions that will be necessary to implement those recommendations.
On May 27, 2010, the FAA published new rules (contained in 14 CFR §92.225 and §91.227) mandating airspace and avionics performance requirements after January 1, 2020. This mandate allows operators approximately 10 years to ensure that their aircraft are properly equipped.
The new rules will require operators to have ADS-B Out avionics in place when operating in:
- Class A, B, and C airspace
- All airspace at and above 10,000 feet MSL (mean sea level) over the 48 contiguous United States and the District of Columbia
- Within 30 nautical miles of airports listed in 14 CFR §91.225, from the surface up to 10,000 feet MSL
- Class E airspace over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles, at and above 3,000 feet MSL.
FAA Advisory Circular 90-114 contains guidance on compliance with the new rules including an overview of the ADS-B system, general operating procedures, and performance requirements.
To view upcoming ADS-B mandates in other countries around the world, visit NBAA’s Communication, Navigation and Surveillance Timeline.
Operator Approval for ADS-B
While no specific approval is required for operations over the U.S., other countries around the world are requiring approval from operators’ civil aviation authority. The FAA and NBAA are working to minimize the effects of these requirements.
Approvals for operations outside the U.S. can be obtained through OpSpec/MSpec/LOA A153 ADS-B Out Operations Outside of U.S.-Designated Airspace. Be sure to check with a ground handling service provider for trips outside the U.S. to determine if ADS-B is required to be installed or approved.