ADS-B Frequently Asked Questions (FAQs)Questions
- Why is the FAA deploying ADS-B technology?
- How was the ADS-B ground system certified, and how will it be re-certified?
- Is the FAA looking at ways to offset the relatively high cost burden and increase the benefits of ADS-B for general aviation?
- Will the ADS-B system be implemented as an enforcement tool to collect user fees, carbon offsets, tax assessments, or for FAA enforcement actions?
- What other solutions were examined for NextGen and what were the reasons for the decision to implement ADS-B over other alternatives such as Loran enhancement, ground station Mode C transceivers, or Mode S?
- ADS-B provides altitude, aircraft number, and vertical air speed. Will it also furnish horizontal air speed?
- The final rule mandates ADS-B Out only. Is this correct?
- How will the new ADS-B Out rule effect me?
- What equipment is required by the new rule?
- Do my current avionics meet the performance requirements of the rule?
- When do I have to equip?
- Will aircraft be able to fly in a non-transponder area without ADS-B?
- What is the difference between ADS-B Out and ADS-B In?
- What are ADS-B In broadcast services?
- I have traffic and weather advisory information now. How are ADS-B In broadcast services different from these?
- ADS-B In allows operators to get traffic and data-linked geographical weather for free. Is it similar to XM weather some pilots receive now?
- Does TIS-B broadcast primary radar?
- Is FIS-B free? Is TIS-B free?
- How do existing traffic display systems integrate with ADS-B?
- Is the FAA considering subsidizing equipment to help convert existing transponders?
- Will Mode C transponders be required indefinitely?
- Can present-day Mode S transponders be converted to ADS-B units and at what costs?
- Please explain the differences between the Universal Access Transceiver (978 MHz) and the 1090ES. What are the advantages and disadvantages of each?
- Can 1090ES be installed for ADS-B Out and UAT for ADS-B In?
- Do you think the manufacturers will build a UAT/1090ES combination box?
- Will the FAA allow portable/handheld units, or will they have to be panel mounts only?
- What specific equipment will be required for ADS-B Out compliance?
- What will it cost to purchase and install ADS-B Out?
- What equipment is required to receive and display ADS-B In?
- What are the limitations on ADS-R (rebroadcast) coverage?
- Will the information broadcast by ADS-B Out be encrypted for security purposes?
- When will ADS-B services be available in my area?
- Do aircraft flying below 18,000 feet (Class A airspace) have the option of using either the 1090ES or UAT?
- Can I install only ADS-B In?
- Is weather information broadcast on 1090ES?
- Do I need to modify my transponder?
- Must my position source be GPS?
- What is uncompensated latency?
- Do I have to use the same altitude source for ADS-B as my TCAS is using? If so, why?
- Does the GPS antenna transmit ADS-B data?
- How did implementation of ADS-B affect the airspace in the Gulf of Mexico?
- Can I find the latest information on the operational status of a radio station on your website?
- What is the range of the ADS-B radio station?
- Where have you been installing the ADS-B radio stations?
- What is the change in the Technical Standard Order? Change from A to B?
- If I am using UAT, do I need to change the Mode C transponder?
- What are you doing with aircraft equipped under Capstone to meet the DO-282-B requirement?
ADS-B is an environmentally friendly technology that enhances safety and efficiency, and directly benefits pilots, controllers, airports, airlines, and the public. It forms the foundation for NextGen by moving from ground radar and navigational aids to precise tracking using satellite signals.
With ADS-B, pilots for the first time see what controllers see: displays showing other aircraft in the sky. Cockpit displays also pinpoint hazardous weather and terrain, and give pilots important flight information, such as temporary flight restrictions.
ADS-B reduces the risk of runway incursions with cockpit and controller displays that show the location of aircraft and equipped ground vehicles on airport surfaces – even at night or during heavy rainfall. ADS-B applications being developed now will give pilots indications or alerts of potential collisions.
ADS-B also provides greater coverage since ground stations are so much easier to place than radar. Remote areas without radar coverage, like the Gulf of Mexico and parts of Alaska, now have surveillance with ADS-B.
Relying on satellites instead of ground navigational aids also means aircraft will be able to fly more directly from Point A to B, saving time and money, and reducing fuel burn and emissions.
The improved accuracy, integrity and reliability of satellite signals over radar means controllers eventually will be able to safely reduce the minimum separation distance between aircraft and increase capacity in the nation's skies.
ADS-B systems are certified for aircraft and for vehicles on the ground. For aircraft, there is a requirement for continuing airworthiness certifications that include verifying the proper operation of avionics subsystems.
FAA Technical Operations personnel certify ADS-B for use on air traffic control automation platforms before ADS-B is turned on during Initial Operating Capability (IOC). FAA Technical Operations personnel also perform regularly scheduled certifications of the ADS-B service at each facility where ADS-B is used for air traffic control.
The entire ADS-B system was approved for use throughout the national airspace system when the FAA Administrator made the In-Service Decision in September 2010. Training and operating guidelines will be implemented at each air traffic facility as ADS-B is deployed. Deployment throughout the nation is targeted for completion in 2014.
Is the FAA looking at ways to offset the relatively high cost burden and increase the benefits of ADS-B for general aviation?
The FAA believes free ADS-B broadcasts of traffic, weather, and aeronautical information yield significant safety benefits to general aviation. The agency continues to look for ways to lower costs and provide even more benefits. For instance, the FAA has tasked an Aviation Rulemaking Committee with examining all aspects of ADS-B In, including recommending new applications that have potential high-value benefits to general aviation. This committee is composed of members from major organizations within the aviation community, including Heidi Williams from AOPA (Aircraft Owners and Pilots Association), Steve Brown from NBAA (National Business Aviation Association), manufacturers, and more. The committee is slated to make a final report to the FAA by September 30, 2011, and to submit detailed recommendations on next steps for ADS-B by June 2012. In parallel, the FAA is funding avionics standards development for the "Traffic Situation Awareness with Alerts" ADS-B In application. This application is expected to yield significant safety benefits for general aviation users who do not have TCAS (Traffic Alert and Collision Avoidance System) equipment.
Will the ADS-B system be implemented as an enforcement tool to collect user fees, carbon offsets, tax assessments, or for FAA enforcement actions?
The FAA has no plans to use ADS-B as an enforcement tool to collect fees, carbon offsets, or tax assessments. The FAA does need to ensure that ADS-B transmissions being broadcast from aircraft comply with the established performance and parameter-reporting requirements identified in the ADS-B Out rule in Title 14 CFR Part 91. The FAA Flight Standards office may take enforcement action to ensure aircraft comply with these regulations.
What other solutions were examined for NextGen and what were the reasons for the decision to implement ADS-B over other alternatives such as Loran enhancement, ground station Mode C transceivers, or Mode S?
The FAA determined the new surveillance system would need to supply these capabilities to lay the foundation for NextGen:
- Core Surveillance. Perform as well as or better than today's surveillance system, while also enabling multifunction capabilities. Deliver services cost-effectively.
- Cockpit Advisory Services. Provide traffic, weather, and database products to improve pilots’ situational awareness and decision-making abilities.
- Cockpit Critical Services. Enable advanced cockpit display applications that would improve capacity by allowing aircraft to fly safely with less separation and ultimately transfer some separation responsibility from air traffic control to the pilot.
In its analysis, the agency also considered the possibility of doing nothing and retaining all existing radar until 2035.
Two alternatives for ground and air-to-air surveillance services were considered along with ADS-B because they met two of the three above criteria (Loran, Mode S, and Mode C technologies did not). These were radar replacement and multilateration. Radar replacement could supply core surveillance and cockpit advisory services, but could not support air-to-air cockpit services and paid back only a fraction of its implementation costs in benefits. Multilateration did not support air-to-air applications. Only ADS-B supported all required and desired capabilities and was found to provide sufficient benefits to the FAA and to aircraft operators within 23 years of implementation.
ADS-B provides altitude, aircraft number, and vertical air speed. Will it also furnish horizontal air speed?
In fact, ADS-B reports two kinds of altitudes: barometric and geometric. Barometric or pressure altitude is the one pilots know best – this is the altitude that is displayed on the altimeter in the aircraft. Geometric altitude is calculated by GPS (Global Positioning Satellites) as the height of the aircraft above the earth ellipsoid. These two altitudes are not the same, but having both allows for applications that require one or the other as an altitude source and provides a means of verifying correct pressure altitude reporting from aircraft.
ADS-B does not report vertical or horizontal airspeed. Instead, ADS-B reports horizontal and vertical velocity relative to the Earth. This velocity is useful for air traffic control functions and ADS-B applications. Airspeed can be provided by other aircraft sensors.
Yes, only ADS-B Out is mandated, and only within certain airspace. Title 14 CFR § 91.225 defines the airspace within which these requirements apply.
On January 1, 2020, when operating in the airspace designated in 14 CFR § 91.225 (outlined below) you must be equipped with ADS-B Out avionics that meet the performance requirements of 14 CFR §91.227. Aircraft not complying with the requirements may be denied access to this airspace.
Under the rule, ADS-B Out performance will be required to operate in:
- Class A, B, and C.
- Class E airspace within the 48 contiguous states and the District of Columbia at and above 10,000 feet MSL, excluding the airspace at and below 2,500 feet above the surface.
- Class E airspace at and above 3,000 feet MSL over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles.
- Around those airports identified in 14 CFR part 91, Appendix D.
The ADS-B Out rule does not apply in the airspace defined in items 1 and 2 above for any aircraft that was not originally certificated with an electrical system or that has not subsequently been certified with such a system installed, including balloons and gliders.
The rule specifies ADS-B Out equipment compliant with either Technical Standard Order (TSO)-C154c (Universal Access Transceiver) or TSO-C166b (1090 ES). However, to operate in Class A airspace, aircraft are required to equip with avionics certified to TSO-C166b.
Your avionics shop and equipment manufacturer can help you determine if your current equipment will meet the performance requirements of the rule and can advise you on available options and costs associated with any required upgrades. Likewise, they can advise you on equipment needed if you wish to install ADS-B In capability (e.g. FIS-B, TIS-B) – ADS-B In is not required under the current ADS-B Out rule. Advisory Circular 20-165 and 20-172 contain information about rule-compliant equipment installation and certification requirements and ADS-B In requirements.
The rule requires ADS-B Out performance by January 1, 2020, to operate in designated airspace. If you never fly into ADS-B-designated airspace, then there is no requirement to equip.
The ADS-B ground infrastructure is being deployed now and will be fully deployed by 2014, so those who choose to equip early will realize benefits long before the mandate.
For the most part, the ADS-B Out mandate covers the same airspace where transponders are required. However, to be sure of the regulatory requirements it is best to check 14 CFR § 91.225 for ADS-B-designated airspace and 14 CFR § 91.215 for transponder-designated airspace.
ADS-B Out is the ability to transmit a properly formatted ADS-B message from the aircraft to ground stations and to ADS-B-In-equipped aircraft. ADS-B In is the ability of an aircraft to receive information transmitted from ADS-B ground stations and from other aircraft. ADS-B In is not mandated by the ADS-B Out rule. If an operator chooses to voluntarily equip an aircraft with ADS-B In avionics, a compatible display is also necessary to see the information. . Refer to AC 20-172 for information on ADS-B in installation and certification.
ADS-B In pilot cockpit advisory services consist of Flight Information Service-Broadcast (FIS-B) and Traffic Information Service-Broadcast (TIS-B). These are free services transmitted automatically to aircraft equipped to receive ADS-B In.
FIS-B provides a broad range of textual/graphical weather products and other flight information to the general aviation community. FIS-B is only available on the 978MHz Universal Access Transceiver (UAT) equipment. FIS-B includes the following:
- Aviation Routine Weather Reports (METARs)
- Non-Routine Aviation Weather Reports (SPECIs)
- Terminal Area Forecasts (TAFs) and their amendments
- NEXRAD (regional and CONUS) precipitation maps
- Notice to Airmen (NOTAM) Distant and Flight Data Center
- Airmen's Meteorological Conditions (AIRMET)
- Significant Meteorological Conditions (SIGMET) and Convective SIGMET
- Status of Special Use Airspace (SUA)
- Temporary Flight Restrictions (TFRs)
- Winds and Temperatures Aloft
- Pilot Reports (PIREPS)
- Turbulence NOWcast
- Icing NOWcast
- Cloud Tops
- 1 minute AWOS – uplinked every 10 minutes
TIS-B is an advisory-only service available to both 1090ES and UAT equipment users. TIS-B increases pilots’ situational awareness by providing traffic information on all transponder-based aircraft within the vicinity of the ADS-B In equipped aircraft receiving the data.
I have traffic and weather advisory information now. How are ADS-B In broadcast services different from these?
The main difference is that ADS-B In broadcast services do not require subscription or usage fees. If you choose to equip, ADS-B traffic, weather, and aeronautical information services are available to you free of charge.
ADS-B In allows operators to get traffic and data-linked geographical weather for free. Is it similar to XM weather some pilots receive now?
Yes. ADS-B's Flight Information Services-Broadcast (FIS-B) provides all of the information you would get with an XM basic subscription, and more. In fact, at no subscription cost to the user, the ADS-B FIS-B product today is comparable to the mid-to-high-level XM subscription. The FAA currently is discussing with the vendor the possibility of adding even more "no-cost" products to the FIS-B service, such as:
For tracks that are initiated with secondary radar, TIS-B will update the track if there is a momentary loss of secondary and only the primary is available. For surface service volumes, TIS-B uplinks primary-only tracks because vehicles operating on airport surfaces may not be equipped with transponders or ADS-B Out.
TIS-B is a free service available to aircraft operators equipped with ADS-B Out and ADS-B In. FIS-B is available free to any operator with the ability to receive and display the data that is broadcast on the Universal Access Transceiver (UAT) or the 978 MHz link.
There are several multi-function displays on the market that interface with ADS-B. Some ADS-B avionics and transponders are produced by the same manufacturer. Before you finalize a purchase, check with an installer or avionics manufacturer to ensure the equipment is able to interface with ADS-B avionics. Refer to AC 20-172 for information on ADS-B In installation and certification guidance.
Not at the current time.
The FAA is considering additional changes in the national airspace system, such as for TCAS. These changes, may at some future date, reduce or eliminate the need for transponder equipage.
Some manufacturers are working to develop upgrade paths for Mode S transponders. You should ask them for details and cost information.
Please explain the differences between the Universal Access Transceiver (978 MHz) and the 1090ES. What are the advantages and disadvantages of each?
There are advantages and disadvantages to each. Aircraft that fly internationally and aircraft that require TCAS (Traffic Collision Avoidance System) are already operating with Mode S transponders and many have older versions of ADS-B Out on 1090ES MHz. Aircraft flying in Class A airspace must operate on the 1090ES MHz frequency. General aviation users who choose the UAT (978 MHz) link may take advantage of the ADS-B traffic, weather, and aeronautical services that are transmitted on the UAT frequency at no charge but must retain their current ATCRBS transponder. Mode S, 1090-ES users can operate in all airspace, but cannot receive FIS-B services.
This represents a configuration that is feasible and permitted by the FAA. However, market options may limit the current availability of these type configurations. The UAT-receive feature can provide for the reception of both TIS-B and FIS-B services for traffic information as well as aeronautical and NAS-status data. The FAA ground system supports providing TIS-B and FIS-B services to these aircraft, and to any aircraft that may be equipped with dual-receive capability. Operators wishing to equip with these configurations should consult with avionics manufacturers on their offerings, including required equipment certifications from the FAA's Aircraft Certification office that exist or are planned in the future.
Several manufacturers are in the process of engineering or producing these devices. You can probably expect to see them on the market soon.
Installed transponders and GPS units must meet certification standards. Handheld devices and displays that serve only for situational awareness have more flexibility and are not certified installations. In order to comply with 14 CFR § 91.225 and 91.227 aircraft intended to fly in ADS-B airspace must have installed and certified equipment. Portable installations are not compliant to the rule and would only be usable for receiving FIS-B services for situational awareness. The FAA is in the early stages of investigating a portable device for glider aircraft.
You would need to equip with either a TSO (Technical Standards Order)-C166b or TSO-C154c certified device, depending on the airspace you wish to access.
Since the technical requirements and rule have been finalized, more manufacturers have introduced equipment to the market at a range of price points with a variety of options. We expect to see this trend continue as competition increases. For specific costs, consult your avionics manufacturers or supplier.
ADS-B In requires either a TSO-C166b- or TSO-C154c-compatible device, along with a processing system and cockpit display that conforms to TSO-C195. The new advisory circular for ADS-B In is AC 20-172 and a revision to TSO-C195 should be published in the fall of 2011.
ADS-R coverage is provided wherever an ADS-B Out- and ADS-B In-equipped aircraft is within range of an ADS-B ground station. Aircraft will not receive ADS-R if they are not appropriately equipped or within coverage of the ADS-B ground system.
ADS-B data can be received by any aircraft, vehicle, or ground station equipped to receive ADS-B. No specific encryption is specified.
ADS-B services are already available in areas where ground systems are operating, and the vendor is moving quickly to expand the deployment across the nation. The FAA expects to have ADS-B pilot situational awareness broadcast capability fully deployed by 2013 covering areas where radar services are provided today, in addition to places like the Gulf of Mexico and parts of Alaska where radar siting was not possible.
Do aircraft flying below 18,000 feet (Class A airspace) have the option of using either the 1090ES or UAT?
Yes, aircraft can equip with either option for operations outside Class A airspace.
Not to meet the rule requirement. A certified rule compliant system must have broadcast capability. To receive all ADS-B In services from the ADS-B ground infrastructure, aircraft must broadcast valid ADS-B Out messages that indicate their ADS-B-In capability. Also, by attempting to install ADS-B In only, you would not allow neighboring aircraft to benefit from seeing you (also denying yourself a safety benefit from making other pilots aware of your position).
No. FIS-B provides weather data and it is only available on the UAT or 978MHz link due to bandwidth considerations.
Modification of some Mode S transponders may be possible and save you money. Older transponders, particularly ATCRBS transponders, are probably not upgradeable and would require replacement. Whether or not a transponder is upgradable is a question for the avionics manufacturer or supplier to determine the answer.
If your aircraft has an ATRCBS or Mode S transponder and you wish to equip with UAT, changes may be needed in the transponder so that MODE A, IDENT, and Mode C information provided to the transponder and UAT unit is identical. It is best to consult the manufacturer to determine specific requirements for your installation.
Any position source that meets the performance standards of the rule (14 CFR § 91.227) can be submitted for certification. GPS is currently the only available positioning source known to meet all of the requirements defined in the ADS-B Out rule.
Uncompensated latency is any delay in the time lapse between calculating the aircraft position and broadcasting that information that cannot be compensated for in the avionics by extrapolating the position information of the target.
Yes. The altimetry source used by the transponder must also be the source of altimetry information transmitted by ADS-B. If two different sources are used, a pilot may be flying at one altitude while the aircraft is transmitting a different altitude to the controller.
Before ADS-B, surveillance was not available in the Gulf at low altitudes or beyond 200 nautical miles from the coast. Now with ADS-B in place, air traffic control can provide 5-nautical mile separation to low-flying aircraft and to aircraft traversing the Gulf, provided the aircraft have certified ADS-B Out equipage.
Generic information is available on our website.
In general, the range would depend on your aircraft's altitude and any terrain that might block your line of site with the radio station. However, there are also practical limits due to transmitter power and receiver sensitivity. Line-of-sight range to a radio is typically 150 nautical miles or greater.
Radio stations are installed in optimum locations to meet coverage requirements where power and telecommunication services are available. ITT Corp., the vendor in charge of the deployment, works closely with AT&T and other tower companies to gain access to many cell phone towers that can be used for installations.
Check Advisory Circular 20-165 as well as TSO-C154c and TSO-C166b for current certification and installation standards for ADS-B Out.
Not specifically because of UAT, but you may need to as a result of interface or compatibility issues to ensure the same altitude encoder data is provided to both the transponder and ADS-B Out avionics. Check with your avionics manufacturer or installer.
The FAA is working with avionics manufacturers to find an upgrade solution.