What is ads-b and how we can help

Starting January 1, 2020, you must be equipped with ADS-B Out to fly in most controlled airspace


An ADS-B Out transmitter alone will not be sufficient to meet the requirements outlined in 14 CFR 91.227. To comply with the requirements for the ADS-B Rule, the aircraft must be equipped with a Version 2 ADS-B Out transmitter and a compatible GPS Position Source. There are two ADS-B avionics systems available:

  • Mode S transponder-based (1090 MHz) ADS-B equipment must meet the performance requirements of Technical Standard Order TSO-C166b. For aircraft operating above FL180 (18,000 feet) or internationally, you must be equipped with a Mode S-transponder-based ADS-B transmitter. For aircraft operating below 18,000 feet and within U.S. airspace, you must be equipped with either a Mode S transponder with Extended Squitter or

  • Universal Access Transceiver (UAT) equipment must meet the performance requirements of TSO-C154c. UAT equipment provides the ability to receive traffic and weather data provided by the FAA ADS-B network.

The FAA recommends a WAAS GPS that is compliant with TSO-C145 or TSO-C146. These units are readily available for general aviation and provide sufficient performance to meet the 14 CFR 91.227 requirements. Avionics vendors offer stand-alone GPS receivers and package them with ADS-B transmitters or with GPS Navigators. Mixing and matching GPS systems with ADS-B transmitters in the field is not permitted unless the equipment pairing was shown to be compatible via a previous certification effort with the FAA (for example, an STC). Be sure to contact your manufacturer if you are unsure which GPS systems are approved for your ADS-B transmitter.

The Installation Approval for ADS-B OUT Systems memo explains the FAA's policy regarding installation of ADS-B Out systems into civil aircraft.


With ADS-B operational across the country, pilots in equipped aircraft now have access to services that provide a new level of safety and efficiency.

Operators equipped with ADS-B Out will enjoy more efficient spacing and optimal routing in non-radar environments, including the busy airspace in the Gulf of Mexico, mountainous regions of Colorado and the lower altitudes of Alaska.

Aircraft equipped with ADS-B out will enhance the Air Traffic Controller's awareness of aircraft in the airspace. Radars used today can take anywhere from 5 to 12 seconds to update an aircraft's position. ADS-B equipment provides air traffic control (ATC) with updated aircraft information almost every second. This enables controllers to identify and resolve potentially hazardous situations quickly and effectively. Because of the FAA's requirements for ADS-B service, in many areas of the United States, coverage exists at lower altitudes than current ATC radars.


Improved Safety

ADS-B In-equipped aircraft have access to Flight Information Service–Broadcast (FIS-B), which broadcasts graphical weather to the cockpit as well as text-based advisories, including Notices to Airmen and significant weather activity. These are available only with a Universal Access Transceiver (UAT).

ADS-B In also gives pilots access to Traffic Information Service–Broadcast (TIS-B), which provides altitude, ground track, speed and distance of aircraft flying in radar contact with controllers, and within a 15-nautical mile radius, up to 3,500 feet above or below the receiving aircraft's position. All of this greatly enhances pilot safety.


Situational Awareness

Pilots of ADS-B In-equipped aircraft can see the location of surrounding aircraft and graphic weather on their cockpit displays. It's a similar view to what air traffic controller see, creating an environment of shared situational awareness and crucial see-and-avoid capability. ADS-B Out information can be broadcast on two frequencies, 1090 MHz and 978 MHz. Automatic Dependent Surveillance-Rebroadcast (ADS-R) rebroadcasts data from one frequency to the other, providing aircraft operating on both ADS-B links the ability to see each other on their traffic displays.

ADS-B In also transmits notices of important flight information, such as temporary flight restrictions or closed runways. And ADS-B In can help pilots avoid terrain in low-visibility situations since terrain maps can be easily added to cockpit displays.

These ADS-B pilot advisory services are provided at no cost to the user.

Search and Rescue

The highly precise GPS-based surveillance provided by ADS-B also improves the ability to perform life-saving search and rescue missions. Air traffic controllers tracking aircraft with ADS-B Out have more accurate information about last reported positions, helping to take the "search" out of search and rescue. ADS-B Out avionics transmit data approximately once every second, and therefore enables more precise tracking of aircraft compared with the current radar sweep rates of 3-15 seconds. The smaller footprint of ADS-B ground radios enables their placement in areas where a radar site would be unfeasible, such as mountainous terrain. Air traffic controllers have better information about an airplane's last position, thereby reducing the critical window of time involved in a search and rescue operation.

ADS-B In & Out

ADS-B stands for Automatic Dependent Surveillance – Broadcast:

  • Automatic because it periodically transmits information with no pilot or operator involvement required.

  • Dependent because the position and velocity vectors are derived from the Global Positioning System (GPS) or other suitable Navigation Systems (i.e., FMS).

  • Surveillance because it provides a method of determining 3 dimensional position and identification of aircraft, vehicles, or other assets.

  • Broadcast because it transmits the information available to anyone with the appropriate receiving equipment.

ADS-B replaces radar technology with satellites, bringing major advantages. Radar relies on radio signals and antennas to determine an aircraft's location. ADS-B uses satellite signals to track aircraft movements.



ADS-B Out works by broadcasting information about an aircraft's GPS location, altitude, ground speed and other data to ground stations and other aircraft, once per second. Air traffic controllers and aircraft equipped with ADS-B In can immediately receive this information. This offers more precise tracking of aircraft compared to radar technology, which sweeps for position information every 5 to 12 seconds.

Radio waves are limited to line of site meaning radar signals cannot travel long distances or penetrate mountains and other solid objects. ADS-B ground stations are smaller and more adaptable than radar towers and can be placed in locations not possible with radar. With ground stations in place throughout the country, even in hard to reach areas, ADS-B provides better visibility regardless of the terrain or other obstacles.

Aircraft operating in most controlled U.S. airspace must be equipped with ADS-BOut by January 1, 2020.



ADS-B In provides operators of properly equipped aircraft with weather and traffic position information delivered directly to the cockpit. ADS-B In-equipped aircraft have access to the graphical weather displays in the cockpit as well as text-based advisories, including Notices to Airmen and significant weather activity.

The FAA provides three forms of ADS-B In Services (Ref. AIM Chapter 4, Section 5(PDF)).

Traffic Information Services – Broadcast (TIS-B)

TIS-B is a client-based service that provides ADS-B Out/In equipped aircraft with surveillance information about aircraft that are not ADS-B equipped. To qualify as a TIS-B target, an aircraft must be equipped with a transponder, and be within radar coverage.

Automatic Dependent Surveillance ‐ Rebroadcast (ADS-R)

ADS-R is a client-based service that relays ADS-B information transmitted by an aircraft broadcasting on one link to aircraft equipped with ADS-B In on the other link. For example, the information for an aircraft equipped with a 1090MHz ADS-BOut system will be re-broadcasted to an aircraft equipped with ADS-B In on the UAT(i.e. 978MHz) frequency, and vice versa.

Flight Information Services – Broadcast (FIS-B)

FIS-B provides the meteorological and aeronautical data to the cockpit. This service is not a client-based service, but rather is always broadcast into the airspace on the UAT frequency. This information is not broadcast on the 1090MHz frequency.

Some of the currently available FIS-B products are:

  • Airmen's Meteorological Information (AIRMET)

  • Significant Meteorological Information (SIGMET)

  • Convective SIGMET



  • Regional NEXTRAD



  • Special Use Airspace (SUA) Status

  • Terminal Aerodrome Forecast (TAF)

  • Winds & Temperatures Aloft

  • TIS-B Service Status

Source: FAA

| Copyright 2018 Affordable Avioncs Inc. | Deepun Desai | Chino Airport, CA, 91710, USA | +1 (909) 606-9876 |