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Frequently Asked Questions

Please see below for questions and answers about equipping. If you don't find your answer here, please contact us at adsb@faa.gov.

Rules

Equipment

Installation

Operation

Benefits


Rules

What are the ADS-B rules?

The FAA published Federal Regulation 14 CFR 91.225 and 14 CFR 91.227 in May 2010. The final rule dictates that effective January 1, 2020, aircraft operating in airspace defined in 91.225 are required to have an Automatic Dependent Surveillance – Broadcast (ADS-B) system that includes a certified position source capable of meeting requirements defined in 91.227. These regulations set a minimum performance standard for both ADS-B Transmitter and the position sources integrated with the ADS-B equipment your aircraft.

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How will the new ADS-B Out rule affect aircraft operators?

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:

  1. Class A, B, and C airspace.
  2. 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.
  3. 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.
  4. 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 not originally certificated with an electrical system or that has not subsequently been certified with such a system installed, including balloons and gliders.

Please refer to "What are the ADS-B rules?" for more information.

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What will make me compliant to fly into ADS-B rule airspace?

See the information on the Installing ADS-B page

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Does the final rule mandate ADS-B Out only?

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.

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Is ADS-B In required?

ADS-B In is not mandated by the ADS-B Final Rule; only ADS-B Out is required in order to fly in the airspace mentioned in 14 CFR 91.225

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When do I have to equip?

The rule requires ADS-B Out equipment 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.

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Does Exemption 12555 mean airlines don't have to equip with ADS-B by the mandate date?

No, Exemption 12555 does not exempt the requirement for ADS-B Out equipment to be installed and operational on aircraft flying in ADS-B rule airspace starting January 1, 2020. It allows for the extended use of an older type of GPS navigation receiver already installed in some aircraft. All other ADS-B Out equipment requirements must still be met and operational by January 1, 2020. The exemption was granted because the kind of GPS navigation receivers suitable for transport category aircraft that meet the ADS-B Out Rule requirements will not be available for purchase or installation in sufficient quantities until closer to 2020. The exemption imposes certain conditions, limitations and additional pre-flight responsibilities on the operators.

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After 2020, can I still fly IFR using my transponder if I am not going into restricted airspace?

The ADS-B Final Rule does not impact the ability for a pilot to fly IFR or VFR. The same rules for flying IFR today will continue to apply come 01/01/2020.

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Can I get a one-time deviation from the requirement?

The ADS-B Out rule allows a mechanism for pilots/operators without ADS-B Out equipment installed to request ATC authorization to deviate from the rule to access ADS-B Out rule airspace. The FAA published a policy in 2019 with guidance on how controllers will handle these aircraft. The policy is clear that unequipped aircraft cannot expect uninterrupted access to ADS-B airspace. The FAA continues to work on the implementation of this policy and authorization request mechanism.

The FAA encourages owners to equip as soon as possible to capture the benefits of ADS-B and to ensure they will be able to access all available airspace once the mandate becomes effective in 2020.

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Can I fly under IFR in non-ADS-B airspace if my aircraft is not equipped with ADS-B?

The requirements of the ADS-B rule apply only to the airspace defined in 14 CFR 91.225, regardless of whether or not the operation is conducted under VFR or IFR. It's an airspace rule and does not apply to any type of operation outside defined airspace.

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If I fly in airspace that does not require a transponder today, will I still be able to fly there without ADS-B Out?

For the most part, ADS-B Out will be required in 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.

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Will Mode C transponders be required indefinitely?

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.

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Will the FAA allow portable/handheld units, or will they have to be panel mounts only?

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.

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What is the timeframe for the European mandate to transfer ADS-B type technology?

Europe has mandated that ADS-B be available for all new aircraft starting June 8, 2016 and all retrofit aircraft be equipped by June 7, 2020.

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What is the change in the Technical Standard Order? Change from A to B?

Check Advisory Circular 20-165B as well as TSO-C154c and TSO-C166b for current certification and installation standards for ADS-B Out.

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Equipment

What equipment is required by the new rule?

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.

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Do my current avionics meet the performance requirements of the rule?

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 ADS-B Out rule. Advisory Circular 20-165B and 20-172B contain information about rule-compliant equipment installation and certification requirements and ADS-B In requirements.

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What specific equipment will be required for ADS-B Out compliance?

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.

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What ADS-B equipment should I install?

Mode S transponder-based (1090 MHz) ADS-B equipment must meet the performance requirements of Technical Standard Order TSO-C166b. For aircraft operating at or above FL180 (18,000 feet), 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.

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What equipment is required to receive and display ADS-B In?

ADS-B In requires either a 1090 MHz Technical Service Order TSO-C166b or 978 MHz Technical Service Order TSO-C154c, along with a processing system and cockpit display that conforms to ADS-B Technical Service Order TSO-C195b. The new advisory circular for ADS-B In is AC 20-172B.

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Must my position source be GPS?

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.

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Why can't I use my phone's GPS sensor?

Commercial GPS sensors are optimized to minimize the time to "first-fix." In other words, they are designed to output a position as quickly as possible using assumptions and measurements available. These assumptions are designed to cope with technical issues facing mobile device users, such as line-of-sight blockage in urban canyon environments, multi-path of the signals, intermittent signals, etc. These techniques and design choices can lead to misleading information given actual signal-in-space errors because the assumptions presume a working satellite.

Aviation-grade GPS sensors are designed to detect and reject satellite measurements that are in error. The driving safety goal is to mitigate the hazard of an incorrect measurement causing dangerous guidance during approach operations using GPS. This design choice causes aviation-grade sensors to acquire a position solution more slowly and can cause valid measurements to be discarded if they exhibit rare normal error distribution. The positive side is that the solution presented has a very high assurance that it lies within the radius of containment calculated by the sensor. This radius of containment is assured at 10E-7 probability and is collectively known as the Integrity metric. The Integrity metric is the basis for all safety analysis performed using GPS measurements, whether the usage is for navigation or surveillance applications.

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What are the risks of using an uncertified position source?

The risk for any GPS receiver, when used to support separation services, is how far the position measurement can be in error without detection. If the position error gets large enough, air traffic control would not be able to provide safe separation between your aircraft and other traffic in your vicinity. FAA and our international peers conducted a safety analysis prior to publishing the final ADS-B rule to determine what this error detection boundary should be and the ADS-B performance requirements are based on the results of this safety analysis.

Certified GPS sensors compare GPS satellite measurements against each other. When a satellite signal error becomes large enough to detect, the receiver will reject that signal. The integrity performance specified in the ADS-B rule depends on the proper operation of this error detection feature. It ensures the safety of using ADS-B positioning based on GPS measurements.

By comparison, uncertified commercial grade GPS sensors assume the system is working properly and do not attempt to detect errors in the satellite measurements. When presented with an erroneous measurement, they will calculate an erroneous position. This was proven to be an unsafe condition by the FAA's safety analysis. Therefore, ADS-B position based on these sensors was prohibited from being used to support air traffic separation and ADS-B air-to-air operations.

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Why are portable ADS-B devices not allowed?

Portable ADS-B Out systems, also known as "suitcase" units, should not be operated (transmitting) aboard any aircraft. While marketing associated with these units may imply approval for use by way of an FCC license, the FAA prohibits their use for the following reasons:

  1. The positioning of portable, suction-cup GPS antennas associated with these units often require they be affixed to front or side windows or glare shield to obtain a usable signal. Such antenna placement obstructs the pilot's view. Connecting wiring also interferes with aircraft controls and instruments.
  2. ADS-B Out avionics require a valid Mode S code to be transmitted to operate properly with ATC automation and other ADS-B aircraft. Mode S codes, also known as the ICAO code, are assigned to an aircraft during registration and then programmed into transponders and ADS-B Out avionics. Mode S codes remain static until a change in aircraft registration or identification (N-number) occurs. Portable units require users to input the Mode S code assigned to each aircraft flown. A high number of Mode S code entry errors have occurred with this procedure, which prevent proper target correlation within ATC automation systems (target drops/traffic conflict alerts), which have resulted in increased workload and unnecessary distractions for pilots and controllers.
  3. The positioning of ADS-B antenna is also vital in the quality of the signal that is transmitted, and if capable, received by the ADS-B device. There have been a number of aircraft identified using portable ADS-B devices that result in degraded performance due solely to poor antenna location.

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Can present-day Mode S transponders be converted to ADS-B units and at what costs?

Some manufacturers are working to develop upgrade paths for Mode S transponders. You should ask them for details and cost information.

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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.

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If I am using UAT, do I need to change the Mode C transponder?

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.

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Do you think the manufacturers will build a UAT/1090ES combination box?

Several manufacturers are in the process of engineering or producing these devices.

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Do I need to modify my transponder?

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.

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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.

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Is the FAA considering subsidizing equipment to help convert existing transponders?

Not at the current time.

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Installation

How is the FAA working with installers and aircraft owners to ensure installations are rule compliant?

The FAA is working closely with installers by providing post-installation checks on aircraft being upgraded or equipped with ADS-B rule-compliant equipment. Currently, an installer/operator can send an e-mail to 9-AWA-AFS-300-ADSB-AvionicsCheck@faa.gov with the following information:

  • Aircraft N-Number
  • ADS-B Manufacturer and Model #
  • Position Source Manufacturer and Model #

With the above information, the FAA will provide a Performance Report that details the installed ADS-B Out systems' compliance to the performance requirements specified in14 CFR §91.227. The Performance Report will highlight any areas that fail to meet required performance levels or avionics settings that are incorrect for the aircraft.

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I operate an amateur built experimental aircraft. What should I install?

The ADS-B Out equipment installed in an aircraft must meet the performance requirements of the ADS-B TSOs. A TSO authorization, issued in accordance with 14 CFR 21 subpart O, is not required. However, ADS-B Out systems and equipment installed or used in type-certificated aircraft must have a design approval issued under 14 CFR 21 (or must be installed by field approval, if appropriate).

The performance requirements include those requirements referenced in section 3 of the applicable TSO (UAT or 1090ES), including considerations for design assurance and environmental qualification. Deviations to the requirements can be approved for equipment which does obtain a TSO authorization, as identified in 14 CFR 91.227.

For experimental category aircraft there is no FAA approval required for the ADS-B Out system installation. Owners of these aircraft may elect to install equipment authorized under a TSO, in accordance with the installation instructions provided by the manufacturer. Alternatively, owners of these aircraft may elect to purchase uncertified equipment. For uncertified equipment, the owner should obtain a statement of compliance from the supplier, along with installation instructions, that identifies that the ADS-B equipment complies with section 3 requirements of the applicable TSO and that, when installed in accordance with the installation instructions, complies with the aircraft requirements of 14 CFR 91.227. The FAA expects manufacturers to perform appropriate engineering efforts to ensure the equipment complies with all requirements of Section 3 of the TSO before issuing their statement of compliance, and expects installers to consider the guidance in the current version of AC 20-165B when performing the installation.

Owners of experimental aircraft should retain the statement of compliance from the equipment supplier in the aircraft records to assist in resolving in-service issues, should they arise. The FAA monitors compliance to the ADS-B Out requirements, and if the equipment, or an installation, is determined to be noncompliant the operator may not be able to enter the airspace designated in 14 CFR 91.225 until the equipment or installation is brought into compliance.

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I operate an S-LSA aircraft. What should I install?

Owners of standard light sport aircraft (LSA) do not need to use certified equipment, but any alteration to install ADS-B must be authorized by the aircraft manufacturer or a person authorized by the FAA (see AC 90-114A). LSA owners may alter their aircraft if they change their airworthiness certificate to an experimental certificate.

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Can 1090ES be installed for ADS-B Out and UAT for ADS-B In?

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.

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What will it cost to purchase and install ADS-B Out?

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. For specific costs, consult your avionics manufacturers or supplier.

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Can I install only ADS-B In?

To receive ADS-B In services from the ground network, aircraft must broadcast valid ADS-B Out messages that indicate their ADS-B In capability. Aircraft with "In" only may "piggy back" off an aircraft receiving ADS-R and TIS-B resulting in a partial picture of the traffic.

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Operation

Is it true that the flights directed into areas of GPS interference testing that has been announced via a NOTAM or operators that are affected by GPS interference will not be in violation of 14 CFR 91.227?

In the event of a scheduled interference outage of GPS, the FAA will issue a Notice to Airmen (NOTAM) that identifies the airspace and time periods that may be affected by the interference. The FAA has determined that it would be impractical and not in the public interest to require operators to avoid the affected area based on the chance that an otherwise compliant flight could experience GPS interference. Accordingly, operators should proceed with their intended operation if the only impediment to their operation is possible planned GPS interference and its potential effect on an aircraft's safe navigation. Operators who are required to perform a preflight availability prediction for the intended route of flight are still required to obtain a satisfactory preflight availability prediction. When a NOTAM identifies the airspace and time periods that may be affected by GPS interference, operators will not be required to alter their route of flight to avoid the area based solely on that NOTAM. If operators encounter actual GPS interference during their flight that results in a degradation of ADS-B Out performance, the FAA will not consider these events to constitute noncompliance with 14 CFR 91.227.

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What happens if there is GPS interference or a GPS outage?

The FAA uses back-up systems to provide resiliency and guard against GPS interference, spoofing, or degradation. The FAA also monitors for GPS interference at its ADS-B and WAAS reference sites. In the event of GPS failure, interference, or spoofing, the FAA maintains backup terrestrial radar to provide resiliency for the National Airspace System.

Radar is the backup to GPS-derived position used for the ADS-B Out signal. If the radar track and GPS track do not correlate, the GPS track is disregarded and air traffic control service continues using backup surveillance.

There are a number of built-in ADS-B message quality indicators in the aircraft that are constantly checking accuracy and integrity of the position source information.

If operators encounter actual GPS interference during their flight that results in a degradation of ADS-B Out performance, the FAA will not consider these events to constitute noncompliance with 14 CFR 91.227.

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What happens if the FAA's ADS-B ground infrastructure goes down? What is the pilot's responsibility if that happens?

If the FAA's ADS-B ground system service is out in a facility, then air traffic control services are still provided using either backup surveillance or procedural separation.

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If the FAA's ADS-B ground infrastructure goes down, can one still fly in ADS-B Out rule airspace? Would the FAA take enforcement action for not complying with ADS-B Out regulations (i.e., flying in ADS-B Out rule airspace without ADS-B Out active)?

If the FAA's ADS-B ground infrastructure goes down, the FAA will not have ADS-B data on aircraft operations in the affected area. Therefore, FAA compliance enforcement in that area at the time of the service outage would not be possible. The pilot can continue to fly in the airspace with air traffic control providing services via backup surveillance or procedural separation. A ground system outage does not make the pilot or aircraft non-compliant.

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Will aircraft operators have to conduct an additional preflight prediction after they receive their first Air Traffic Control (ATC) route clearance for a flight? What if ATC reroutes a flight or there are deviations due to weather? Will these situations be viewed as "NOT IN COMPLIANCE" by the Federal Aviation Administration (FAA) if the GPS performance for these reroutes is below the values required by 14 CFR 91.227 of the Code of Federal Regulations?

Note: If you are a general aviation (GA) pilot and/or flying with ADS-B equipment that uses WAAS as its position source, you are not required to perform a preflight availability prediction. The majority of GA equipment uses WAAS.

Once a pilot has received an ATC route clearance, there is no requirement to conduct a subsequent preflight prediction. Upon receiving a satisfactory preflight availability prediction and an ATC route clearance, the operator will be deemed to have complied with the preflight availability prediction requirement and the performance requirements of 14 CFR 91.227(c)(1)(i) and (iii). The FAA accepts that unanticipated changes in route of flight and environmental conditions may adversely affect ADS-B Out performance relative to 14 CFR 91.227(c)(1)(i) and (iii). ATC will continue to exercise its responsibility for the safe and efficient movement of air traffic, including the routing of traffic to meet those objectives.

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If there are outages to the FAA's Service Availability Prediction Tool (SAPT), are the operators who use tool to meet preflight requirements relieved of that responsibility while it is out of service?

Operators who use SAPT as their preflight prediction tool will not need to conduct a preflight predication for the duration of an SAPT outage. For time periods when a SAPT outage has occurred, the FAA will not initiate compliance or enforcement actions against operators who rely on the SAPT if an operation falls below the performance requirements of 14 CFR 91.227(c)(1)(i) and (iii), despite the technical non-compliance with 14 CFR 91.227. The FAA cautions that, for operators who have already been notified by the FAA of consistent and repeated ADS-B Out performance issues, operating during SAPT outage without first redressing the identified non-performance issue will be considered a continuation of existing non-compliance with 14 CFR 91.227.

What this means is the FAA does not intend to inhibit operators from conducting otherwise permissible operations when the SAPT is unavailable. As such, when there is a SAPT outage, the policy described above will apply to operators who rely on the SAPT if their operation falls below the performance requirements of 14 CFR 91.227(c)(1)(i) and (iii).

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When will ADS-B services be available in my area?

ADS-B services are already available across the U.S. including Hawaii, Alaska, Guam, San Juan, and the Gulf of Mexico. A coverage map is available here.

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What is the difference between ADS-B Out and ADS-B In?

ADS-B Out refers to an aircraft broadcasting its position and other information. ADS-B In refers to an aircraft receiving the broadcasts and messages from the ground network such as TIS-B and FIS-B. 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 20-165B for information on ADS-B OUT and AC 20-172B on ADS-B IN installation and certification.

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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.

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How do existing traffic display systems integrate with ADS-B?

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 20-172B for information on ADS-B In installation and certification guidance.

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Does TIS-B broadcast primary radar?

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.

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Where are the written definitions explaining the icons on the TIS-B display?

The equipment manufacturer would be the best source for providing a description of each icon on the display.

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What are the limitations on ADS-R (rebroadcast) coverage?

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.

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Is weather information broadcast on 1090ES?

No. FIS-B provides weather data and it is only available on the UAT or 978MHz link due to bandwidth considerations.

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Do I have to use the same altitude source for ADS-B as my TCAS/transponder is using? If so, why?

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.

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Does the GPS antenna transmit ADS-B data?

No.

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Will ATC see ADS-B-equipped aircraft at lower altitudes than non-ADSB-equipped aircraft?

The FAA's ADS-B service can detect aircraft at lower altitudes than radar today in many locations. As the FAA enables the use of ADS-B at TRACONs nationwide, ATC uses the data just like radar. ADS-B services are already available in most ATC facilities across the U.S. See our interactive ADS-B airspace map to identify where ADS-B coverage is around your home airport and where you fly.

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Under ADS-B, will ATC always see me as N12345 even if I am not under VFR flight following or an IFR flight plan?

ADS-B Out equipment transmits information about the aircraft's location, ground speed and other data once per second. The broadcast includes the aircraft's unique ICAO address, which for a US registered aircraft is associated with its tail number, as well as the transmission of aircraft's flight ID, which for GA aircraft is generally the registration "N" number, or for commercial/government operator's, their call sign or airline flight number. Air traffic controllers can immediately see this information if they desire, however the controller has display options where they can suppress the N-number for VFR aircraft that are not receiving flight following services, and some controllers will set these options to "declutter" their display. Additionally, GA operators that employ UAT transceivers have the option in VFR operations, when they are squawking 1200 and flying below FL180, to select "anonymous mode", which enables the transceiver to broadcast a randomized flight ID and pseudo-ICAO address. The transceiver reverts back automatically to the assigned ICAO address and default flight ID when the beacon code is changed from 1200.

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Will the information broadcast by ADS-B Out be encrypted for security purposes?

ADS-B data can be received by any aircraft, vehicle, or ground station equipped to receive ADS-B. No specific encryption is specified.

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Will the FAA keep a permanent record of the tracks and other information associated with the flights of ADS-B-equipped aircraft? or is the information deleted after a period of time?

Radar and ADS-B surveillance information is retained for at least six months and sometimes longer for research and investigative purposes.

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Benefits

Why is the FAA transitioning away from radar and towards ADS-B technology?

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.

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What other surveillance 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 sites 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.

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What are FAA ADS-B In broadcast services?

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:

  • Airmen's Meteorological Conditions (AIRMET)
  • Significant Meteorological Conditions (SIGMET) and Convective SIGMET
  • Aviation Routine Weather Reports (METAR)
  • Non-Routine Aviation Weather Reports (SPECI)
  • NEXRAD (regional and CONUS)
  • Notice to Airmen (NOTAM) Distant and Flight Data Center
  • Pilot Reports (PIREP)
  • Status of Special Use Airspace (SUA)
  • Terminal Area Forecasts (TAF) and their amendments
  • NOTAM – textual Temporary Flight Restrictions (TFRs)
  • Graphical TFRs
  • Winds & Temperature Aloft
  • TIS-B Service Status
  • Lightning strikes
  • Turbulence
  • Icing, Forecast Potential (FIP)
  • Cloud tops
  • Graphical-AIRMET
  • Center Weather Advisory

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.

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I have traffic and weather advisory information now. How are FAA 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.

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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.

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Is FIS-B free? Is TIS-B free?

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.

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Will we see military aircraft on the TIS-B screen?

Depending on their operational mission, most, but not all, military aircraft will appear as a TIS-B target on ADS-B-In-equipped aircraft.

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This page was originally published at: https://www.faa.gov/nextgen/equipadsb/resources/faq/