Appendix D.
Aircraft Surveillance Applications (ASA) Systems
1. Purpose. The purpose of this Section is to provide certification guidance for design approval of ASA systems and to provide background material as it relates to requirements for aircraft installed equipment.
2. Scope. This Appendix provides certification guidance for design approval of aircraft ASA systems and applications. As described in RTCA/DO-289, MASPS for ASA, there are four subsystems of ASA:
• Automatic Dependent Surveillance Broadcast (ADS-B),
• Surveillance Transmit Processing (STP),
• Aircraft Surveillance and Separation Assurance Processing (ASSAP),
• Cockpit Display of Traffic Information (CDTI).
3. Background. The FAA, in the interests of enhancing safety and air traffic management, and in response to the expressed desires of the aviation community, established the Safe Flight 21 program. This program should provide a broadcast service ground network that will deliver to the cockpit real-time access to weather, traffic, and advisory aeronautical information.
Aeronautical digital communications, or data link, will provide high-speed exchange of textual and graphical information between aircraft and ground based systems.
Capstone, Ohio River Valley, and Free Flight initiatives have developed initial operational deployments incorporating some ASA applications. Additionally, during 2004, sites were established between Florida and New Jersey as part of the East Coast Safe Flight 21 program.
Subsequently, approval is being sought for a national deployment of an ADS-B ground infrastructure.
ASA considers previously defined ADS-B requirements and CDTI concepts. ASA applications were developed with the idea of using ADS-B and TIS-B surveillance information, and providing that information to the flight crew via a CDTI. It was also realized that surveillance and application processing would be required to support these applications, which led to the concept of an Airborne Surveillance and Separation Assurance Processing (ASSAP) subsystem. During early development work on Minimum Operational Performance Standards (MOPS) for ADS-B, CDTI and ASSAP, it became clear that the requirements for these systems needed to be based on the requirements of the applications themselves. As such, the need for an overall concept of ASA was realized. RTCA has published RTCA/DO-289, the ASA MASPS, that provides high-level industry standards for ADS-B, STP, ASSAP, and CDTI.
4. ASA Functional Architecture. The ASA system consists of four major subsystems: a surveillance transmit processing subsystem, a surveillance subsystem (including ADS-B and TIS- B transmit and receive), a surveillance data processing subsystem -- Airborne Surveillance and Separation Assurance Processing (ASSAP), and a display subsystem known as the Cockpit Display of Traffic Information (CDTI). ASA also interfaces with other aircraft systems.
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The Surveillance Transmit Processing (STP) subsystem prepares the required surveillance information from on-board aircraft sensors for the ADS-B Transmit Subsystem. Traffic Information Service Broadcast (TIS-B) messages are processed to include similar surveillance information obtained through ground surveillance systems.
The ADS-B/TIS-B Receive Subsystem receives ADS-B and TIS-B messages. The ADS-B/TIS-B Receive Subsystem processes ADS-B and TIS-B messages and provides ADS-B and TIS-B traffic reports to ASSAP.
ASSAP is the processing subsystem that accepts surveillance inputs, e.g., ADS-B/TIS-B reports, and performs surveillance processing to provide reports and tracks, and performs applicationspecific separation assurance processing. Surveillance reports, tracks, and any applicationspecific alerts or guidance are output by ASSAP to the CDTI function. In addition to these interfaces and depending on the actual ASA application, ASSAP may interface to the Flight Management System (FMS) and / or the Flight Control systems for flight path changes, speed commands, etc. ASSAP also interfaces with:
• The ADS-B transmitter and receiver to support transmission of application-specific messages, etc.,
• Inputs from the own-ship avionics system to obtain state information on own aircraft, and,
• TCAS (TCAS I and TCAS II), for combined displays.
4.1. Position Source, ADS-B, ASSAP and CDTI. Accurate position source information is required to support ASA applications, such as Airport Surface Situational Awareness, where the own-ship and other traffic must be properly located on an airport map display. The Global Satellite System (GNSS), e.g., Global Positioning System (GPS), is the preferred source of this position data, but potentially any source of aircraft position data meeting the requirements of the intended ASA application may be used. GNSS by itself (i.e., without augmentation) will meet the performance, in terms of accuracy and integrity, needed to support most ASA applications.
Other ASA applications may require higher position accuracy and integrity and may require augmentation by differential correction systems such as the Wide Area Augmentation System (WAAS) or the Local Area Augmentation System (LAAS). For applications that require high availability of the navigation data, GNSS augmentation systems or a secondary source of navigation information may be necessary.
With ADS-B, each aircraft determines its own position and other state information, and broadcasts this information over a data link. Other aircraft may receive this information, and compare it with their own position to accurately determine relative positioning. Ground systems may also use ADS-B information to augment or replace less accurate radar-based surveillance information, or to provide cost effective surveillance coverage in non-radar airspace.
TIS-B has been developed to provide the position data of traffic not equipped with ABS-B. TIS- B may also rebroadcast surveillance information from different ADS-B links. ASSAP takes the incoming surveillance information and processes it according to the appropriate ASA application(s) as selected by the flight crew.
Display of traffic is accomplished through a Cockpit Display of Traffic Information (CDTI). The CDTI provides the flight crew interface to the ASA system. It displays traffic information Page D-2 APPENDI X D
processed by the ASSAP. It provides other necessary information, such as alerts and warnings, and guidance information. The CDTI also accepts flight crew inputs to the ASA system, such as display preferences, application selection, and designation of specific targets and parameters for certain applications.
4.2. TIS-B. Not all aircraft will be equipped to broadcast their position via ADS-B. It is anticipated that there will be a long transition period over which aircraft owners decide to equip their aircraft, and that some aircraft owners may choose never to equip. In addition, situations will occur where the ADS-B reporting equipment on an aircraft is not operating although it is installed.
To fill this information gap, the concept of Traffic Information Service Broadcast (TIS-B) was developed. Within their coverage areas, ground surveillance systems can determine the positions of transponder-equipped aircraft and broadcast this position data to ASA-equipped aircraft via TIS-B. Additional information regarding TIS-B is covered in Appendix F of this AC.
4.3. Relationship To TCAS. The Traffic-Alert and Collision Avoidance System (TCAS II), Version 7, referred to internationally as the Airborne Collision Avoidance System (ACAS), provides flight crews with a traffic situation display and with safety alerts. TCAS provides a backup safety system for separation assurance. The integration of TCAS and ASA applications is covered in Appendix G of this AC.
5. ASA System Configurations: ASA Capability Level (ACL) and Transmit Quality Level (TQL) ASA system configurations are defined by ASA Capability Levels and Transmit Quality Levels as described in RTCA/DO-289. ASA applications each have unique requirements to support their operation. Aside from specific state information, applications require that the data received from other Aircraft/Vehicles (A/Vs) (or TIS-B) be of sufficient quality to support use of that state data.
In addition, ATC and some applications require knowledge that an A/V is capable of using an application.
Two parameters Transmit Quality Level (TQL) and ASA Capability Level (ACL) have been developed to broadcast the transmit quality and ASA capabilities.. These parameters are utilized to group similar performance requirements to provide a reduced set of system requirements. The benefits of such groupings lead to:
• Reduced number of equipment configurations.
• Simplified certification due to reduced equipment configurations, thus avoiding a proliferation of system and sub-system dependencies.
• Simplified documentation of requirements.
TQL is independent from ACL. An ACL requires a minimum own-ship TQL so that broadcast data will support the same applications on other A/Vs. However, the TQL may exceed this minimum.
5.1. ASA Capability Level. ACL conveys the applications available, but not necessarily in current use, on the transmitting aircraft. (By available, it is meant that the applications are installed, the flight crew is qualified to use the applications, and the system is currently capable of performing its intended function.) Like TQL, the limited groupings provided by ACL are expected to expedite the manufacture and certification of processing sub-systems. However, ACL also serves two additional functions. It provides other users, including the ground system, APPENDIX D Page D- 3
with information necessary to allow use of some applications, to request use of applications, and to support use of some applications. It also provides the flight crew with information about the application capabilities of their own-ship.
ACL has been defined in such a way to provide groupings of applications that should appeal to specific segments of the aviation community. The levels are intended to be hierarchical to the extent possible.
Transmit-only
The Transmit-only ASA Capability Level indicates that the broadcasting aircraft transmits ADS- B messages, but has no on-board application capabilities available. This could indicate that no applications are installed, the flight crew is not permitted to use the applications, or that there is some sort of failure in their ADS-B receiver, ASSAP, or CDTI subsystems.
Basic ASA Capability Level
The key characteristic of applications in the Basic ASA Capability Level is that other users (other aircraft and ATC) have no operational need to know that the applications are available and operational on the broadcasting aircraft.
Basic ACL includes the Enhanced Visual Acquisition (EVAcq) application, and optionally any combination of Conflict Detection (CD), Final Approach and Runway Occupancy Awareness (FAROA), or Airport Surface Situational Awareness (ASSA). These applications support enhanced situational awareness, but do not alter current separation responsibilities. The CD application also requires alerting functions. The ASSA and FAROA applications require an airport map database.
Note: The definitions for EVAcq, CD, FAROA and ASSA are in the initial revision of ASA MASPS, RTCA/DO-289.
Note: FAROA and ASSA are essentially the same application, only differing in the required databases. The database needed for FAROA (airport runways) is a subset of the database needed for ASSA (runways and taxiways). If an aircraft is equipped with ASSA then it is also equipped with FAROA.
Intermediate ASA Capability Level
Intermediate and higher ACLs contain applications that benefit from or require that other A/Vs or ATC know of the application’s presence and operational status. The applications in the Intermediate ACL will provide tools to help the flight crew maintain appropriate spacing and separation with other aircraft, but will not change the current separation responsibility from ATC to the flight deck.
Intermediate ACL includes the Enhanced Visual Approach (EVApp) application. This application involves cooperation with ATC. Additional system performance criteria, alerting mechanisms, and CDTI capabilities are required to provide spacing and closure information for enhanced visuals approach.
Note: The definition for EVApp is in the initial revision of ASA MASPS, RTCA/DO-289.
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Advanced ASA Capability Levels (Future)
Advanced ASA Capability Levels is reserved for future use. Advanced ACL applications are envisioned to provide a means to shift separation responsibility from ATC to the flight deck in certain airspace or for certain operational procedures, e.g., Airborne Conflict Management (ACM) applications. These applications require maneuvering guidance, as well as additional alerting capabilities. Other advanced applications are envisioned to be short-range applications that have a higher criticality than Basic and Intermediate ACLs, and may have more stringent requirements, e.g., Approach Spacing for Instrument Approaches (ASIA) and Independent Closely Spaced Parallel Approaches (ICSPA).
Note: The definitions for ASIA and ICSPA are in the initial revision of ASA MASPS, RTCA/DO-289.
5.2. Transmit Quality Level (TQL). The Transmit Quality Level broadcast by the on-board ASA transmit subsystem or a TIS-B ground station indicates the quality of the transmitted surveillance information that when used with other data quality parameters, e.g., actual NIC, NAC, SIL, etc., allows users to assess the suitability of the received surveillance information to support a user application. The minimum Navigation Integrity Category (NIC), Navigation Accuracy Category (NAC), and Surveillance Integrity Level (SIL) defined for each TQL are not necessarily those needed for applications, but rather are the minimums for which other attributes of TQL (e.g., continuity), are to be met. The transmit quality level value sent identifies the quality of both the surveillance equipment and the surveillance information transmitted. Transmit quality levels group sets of requirements for surveillance equipment and transmitted surveillance information. TQLs are hierarchical in that higher transmit quality levels announce that a participant supports the capabilities of all lower transmit quality levels.
Note: The definitions for NIC, NAC and SIL are in the initial revision of ASA MASPS, RTCA/DO-289. RTCA MOPS are in development for minimum requirements for NIC, NAC and SIL and should be invoked in future TSO(s).
All A/Vs that transmit ASA data (i.e., ADS-B messages) should assess and transmit their Transmit Quality Levels. TIS-B ground stations should also assess and transmit an appropriate TQL for each A/V. The TQL should be assessed dynamically, so that changes in capabilities are announced, for example, when the equipment no longer qualifies for its previously announced TQL.
The Transmit Quality Level conveys quality characteristics in addition to those already communicated in ADS-B messages, e.g., the actual NAC, NIC, and SIL values for position information. Transmit Quality Level should address the following characteristics:
• Maximum ASA transmit equipment integrity
• Maximum ASA transmit subsystem continuity of service
• Maximum ASA transmit data latency
• Maximum state data latency
• Maximum time error of state data
• Minimum NACp for position information
• Minimum NACv for velocity information
• Minimum NIC for position information
• Minimum SIL for position information APPENDIX D Page D- 5
• Maximum time to indicate integrity change
• Minimum transmitted information requirements
5.3. Applications. There are many proposed applications for ADS-B, some of which are listed in the Automatic Dependent Surveillance Broadcast (ADS-B) MASPS, RTCA/DO-242A and Surveillance Applications (ASA) MASPS, RTCA/DO-289. Applicants proposing to use DO-289 as part of the certification methodology should be aware that the airworthiness and operational assumptions must be validated prior to certification and operational approval. This is necessary to ensure the intended function and failure classification is appropriate for each operational application.
6. Human Factors Considerations. The display of ASA traffic information should follow the guidance discussed in Appendix H of this AC.
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APPENDIX E.
Automatic Dependent Surveillance - Broadcast (ADS-B) Link Systems
1. Purpose. This Appendix provides guidance and background information on airborne ADS-B link systems.
2. Scope. ADS-B is a function on an aircraft that periodically broadcasts its state vector and other data. ADS-B is automatic because no external stimulus (e.g., interrogation) is required to elicit a transmission; it is dependent because it relies on on-board aircraft position sources (e.g., GPS) and on-board link systems to provide this surveillance information to other users.
As discussed in the FAA’s ADS-B Link Decision, ADS-B link systems will consist of a combination of the 1090 Extended Squitter (ES) link, to be used primarily by air carrier and private/commercial operators of high performance aircraft, and Universal Access Transceiver (UAT), to be used primarily by the typical general aviation user. The guidance material in this Appendix addresses both of these ADS-B link systems.
FAA / industry standards for a minimum safety, performance, interoperability and parameter set for ADS-B are under development and are not available for this version of the AC. Therefore, avionics developers should consider the current operating requirements (e.g., Europe, Australia, United States) in order to determine the intended function of the ADS-B system.
3. Description. As stated above, there will be two ADS-B link systems that will be used in the NAS:
1090 MHz ES: 1090 MHz ES is a transmit/receive technique, based on Mode S concepts, that uses periodic 1090 MHz transmissions (extended “squitters”) to broadcast information such as ADS-B messages. The transmit subsystem takes position, velocity, time (PVT) and other data from on-board systems, generates ADS-B messages and broadcasts this information on 1090 MHz as extended squitters. Since the message length of individual extended squitters is limited, it is necessary to encode the ADS-B message efficiently to keep the number of required transmissions to a minimum. The receive subsystem receives extended squitters and outputs the ADS-B messages to other on-board systems, such as a surveillance data processor and/or CDTI.ES capability supports both ADS-B and TIS-B, with their associated potential improvements in safety through future ground and airborne applications; however, ES is presently not operationally required.1090 MHz ES functions are usually integrated with Mode S Transponder functions in the same line replaceable units to share common system resources, although this also is not a requirement.
UAT: UAT is a wideband multi-purpose data link intended to operate globally on a single channel with a channel-signaling rate of just over 1Mbps.UAT supports multiple broadcast services including FIS-B, in addition to ADS-B and TIS-B. This is accomplished using a hybrid medium access approach that incorporates both time-slotted and random unslotted access. UAT can also support independent measurement of range to most other participants using the same link. Future iterations of UAT could also support downlink of various on condition message set data such as automated weather reports. Also, depending upon need,
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UAT functionality can be a medium to transmit ground based GPS augmentation signals to aircraft, a similar function to VHF enabled LAAS corrections but over the UAT.
4. Existing Guidance/Policy. ADS-B requirements are defined in RTCA/DO-242A, ADS-B MASPS. 1090 ES requirements are defined in RTCA/DO-260A, 1090 ES ADS-B and TIS-B MOPS. UAT requirements are defined in RTCA DO-282A, UAT ADS-B MOPS. Mode S Airborne Data Link Processor requirements are defined in RTCA/DO-218B Mode S Airborne Data Link Processor MOPS.
Note: Minimum operational performance standards (MOPS) for the ADS-B message set are being developed by RTCA SC-186.
5. Airworthiness Considerations.
5.1. Significant Technical Issues. Requirements and applications of 1090 ES or UAT data link have not been fully defined. As the ADS-B transmission subsystems themselves do not have any associated applications per se (i.e., the link systems transmit data, but the use of the data is determined by the receiving end user), the aircraft avionics manufacturer should define the intended function based in part on assumptions of the operating requirement. ADS-B data link intended function may be demonstrated for safety, performance and interoperability during the certification process (e.g., STC, TC). . Mode S transponders, that are compliant with ICAO Annex 10, Amendment 77, should meet the European Mode S Extended Squitter operational requirements.
5.2. Flight Data Recording of New Parameters. For Mode S transponders that incorporate extended squitter, the additional transponder parameters for current airspace operations do not add new significant failure modes; therefore flight data recording for accident investigation is not currently required. However, as ADS-B applications are not yet fully defined, further evaluation of unique operational aspects for flight recording purposes may be needed at the time of certification of the end user application.
6. Interoperability Assumptions. Long-term capabilities of ADS-B are not yet fully defined.
Avionics and airframe manufacturers are encouraged to implement an airborne ADS-B architecture (using one of the ADS-B links, either 1090 ES or UAT) that will readily accommodate both ADS-B links. Also, certain air carriers may elect to equip with both 1090ES and UAT capabilities in the near-term as a means of achieving interoperability with general aviation users equipped with only UAT.
The FAA’s link decision is compatible with a joint strategy currently being coordinated between EUROCONTROL and the FAA for implementing ADS-B enabled applications, thus providing for interoperability between the U.S. and Europe.
7. Minimum Equipment Standards. 1090 ES ADS-B link systems should meet the standards defined in TSO-C166, “Extended Squitter Automatic Dependent Surveillance - Broadcast (ADS- B) and Traffic Information Service - Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 Megahertz (MHz).”
UAT ADS-B link systems should meet the standards defined in TSO C154 or later FAA approved version, “Universal Access Transceiver (UAT) Automatic Dependent Surveillance - Broadcast (ADS-B) Equipment Operating on the Frequency of 978 MHz. 1090 MHz ADS-B link systems should meet the standards defined in TSO-C166 or later FAA approved version, Page E - 2 APPENDIX E
“Extended Squitter Automatic Dependent Surveillance – Broadcast (ADS-B) and Traffic Information Service - Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 Megahertz (MHz)”
8. System Safety Assessment. Software criticality levels for transponders that include 1090 ES functionality remain unchanged at RTCA/DO-178A Level 2 or RTCA/DO-178B Level C for altitude reporting. However, additional transponder parameters (e.g., ES) should be classified as minor, where these data are subject to controller verification (reference Mode S /OHA/0001 OHA). Where the system remains the same as the current installation of the TCAS/ATC system, there are no new significant failure modes associated with transponders with extended squitter.
Software criticality levels for UAT or stand-alone 1090 ES link systems are defined in their respective TSO’s.
9. Ground Test and Flight Test. If the Mode S transponder is already certified (such as for TCAS II), the certification of the Mode S extended squitter installation is required for proper transmission (output) of the additional data, and can be demonstrated on the ground with the appropriate ramp test equipment and procedure.
10. AFM. The AFM should document the transponder intended function (e.g., safety, performance, interoperability) based in part on operational assumptions. An AFM limitation may be required to ensure the appropriate use of the equipment based on the certified intended function.
11. Training and Crew Qualification. Crew operating instructions for the use of the ICAO defined format for Aircraft Identification (Flight Number) may be needed.
12. Continuing Airworthiness and Maintenance. Where the system installation remains the same as the current TCAS II/ACAS system, Mode S transponders that incorporate extended squitter result in no changes to current maintenance practices or continuing airworthiness instructions.
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APPENDIX F.
Traffic Information Service - Broadcast (TIS-B)
1. Purpose. The purpose of this Appendix is to provide certification guidance and background material on TIS-B as it relates to requirements for installed and portable equipment. While the TIS-B subsystem consists primarily of ground-based equipment, assumptions about the characteristics of broadcast TIS-B data and subsequent airborne processing of the data are necessary to ensure the overall ASA system will support ASA applications. This Appendix provides guidance material for applicants and certification authorities to evaluate airworthiness of airborne systems that utilize TIS-B data.
2. Description. As described in RTCA/DO-286, TIS-B comprises surveillance services that broadcast traffic information derived from one or more ground surveillance sources to suitably equipped aircraft or surface vehicles. TIS-B augments ADS-B by providing a more complete traffic picture in situations where not all aircraft are equipped with ADS-B. The Fundamental TIS-B Service supports enhanced visual acquisition of other aircraft by the flight crew. The ADS-B Rebroadcast Service translates ADS-B reports received on a particular data link and transmits the reports on the other available ADS-B data links.
The TIS-B system relies on various sources of surveillance information, such as primary and Secondary Surveillance Radar (SSR). Surveillance information is processed and converted for use by ADS-B equipped aircraft. Broadcast services ground stations then transmit TIS-B messages to ADS-B equipped aircraft. The ground stations also receive ADS-B transmissions received from ADS-B equipped aircraft and convey the reports to the TIS-B system to be associated with reports obtained from other surveillance sensors.
3. Scope. The intended function of TIS-B is to provide traffic information about aircraft that is not available via direct reception of air-to-air ADS-B broadcasts. Cases where this information would be desirable are where the target aircraft is not equipped with ADS-B but it is within local radar coverage, or where the target aircraft is ADS-B equipped but is broadcasting on a different data link than the receiving aircraft, or where the reception of common data link signals is limited by line-of-sight blockage or RF interference.
From an airborne systems perspective, the relevant installed equipment for TIS-B reception and processing is the ADS-B/TIS-B receive subsystem which must be capable of receiving and decoding TIS-B messages and the surveillance data processing subsystem which must be capable of correlating TIS-B data with ADS-B data to assemble coherent, individual aircraft tracks and provide them to applications.
4. Applications. The TIS-B Fundamental service supports the following ASA applications:
Enhanced Visual Acquisition for See and Avoid: This application is intended to improve the pilot’s ability to visually acquire other traffic, both in the air and on the ground, so that the pilot can more effectively apply the see-and-avoid principle.
Airport Surface Situational Awareness (ASSA): This application is intended to provide the pilot with an awareness of proximate surface traffic on ramps, taxiways, and runways.
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5. Description. Aircraft Avionics Architectures:
From an aircraft perspective, the Fundamental Service TIS-B data link architecture is defined in the data link MOPS. The data link MOPS specify an ADS-B/TIS-B receive function that is interoperable with ground stations that are compliant to the TIS-B MASPS.
TIS-B surveillance information received via ADS-B support selected ASA. As described in RTCA/DO-289: “The ASA system comprises a number of flight-deck-based aircraft surveillance and separation assurance capabilities that may directly provide flight crews with surveillance information as well as surveillance-based guidance and alerts.” Additional information on the set of specific applications can be found in RTCA/DO-289.
This particular Appendix is intended to provide guidance for avionics implementations limited to support of the Basic ASA capability level (ACL) defined in RTCA/DO-289 that includes Enhanced Visual Acquisition, Conflict Detection, Airport Surface Situation Awareness and Final Approach and Runway Occupancy Awareness.
6. Human Factors Considerations. TIS-B technology necessitates consideration of human factors issues that do not generally apply to ADS-B. Some key differences between TIS-B and ADS-B are:
Ground-based service volumes. The ability for own-ship to receive TIS-B traffic depends on the positions of own-ship and traffic relative to ground sites, versus the positions of own-ship and traffic relative to each other. The result is service availability dynamics and geometries that are not necessarily well matched to the pilots needs. For example, targets that are close to own-ship may drop out, while farther traffic remains. This condition should be noted in the AFM, pilots guide and training.
Loss of multiple targets. TIS-B ground stations transmit information on multiple targets, as opposed to ADS-B aircraft that transmit information on only one aircraft. The loss of a single ADS-B transmission results in the loss of only one aircraft on the display, while the loss of a single TIS-B ground station may result in the loss of multiple aircraft on the display. This condition should be noted in the AFM, pilots guide and training.
Low Performance Traffic Data. The performance of TIS-B traffic data, for both information content (e.g., position accuracy) and data link (e.g., update rate) may be worse than that of air-toair ADS-B traffic, and for some applications and tasks it may be appropriate for the display to depict and handle traffic information based upon performance issues. For example, traffic whose position accuracy is low might be depicted with a unique symbol or data tag element in order for the pilot to visually acquire the target with less workload. Alternatively, traffic that is susceptible to frequent drop-outs might be annunciated differently from drop-outs of high-performance traffic information, to be less distracting to pilots. Human Factors guidance for TIS-B and ADS-B traffic can be found in Appendix H, "Human Factors Considerations for the Display of Traffic Surveillance Information." The display of all traffic information should be demonstrated to be safe and effective.
7. Existing Guidance/Policy References.
• RTCA/DO-286, Minimum Aviation System Performance Standards (MASPS) for Traffic Information Service-Broadcast (TIS-B), contains an initial set of requirements for TIS-B.
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