Appendix A A-12 Table A-1. In-Trail Procedure Initiation/Maneuver Criteria (Reference RTCA DO-312 Supplement) In-Trail Procedure (ITP) Speed/Distance Criteria ITP Distance ≥ 15 nautical miles (NM) and Closing Groundspeed (GS) Differential ≤ 20 knots (kts) ITP Distance ≥ 20 NM and Closing GS Differential ≤ 30 kts Relative Altitude Criteria Difference in altitude between ITP and Reference Aircraft is less than or equal to 2,000 feet Similar Track Criteria Difference in track angles between ITP and Reference Aircraft is less than ±45 degrees Position Accuracy for ITP and Reference Aircraft ITP and Reference Aircraft data with horizontal position accuracies of at least 0.5 NM (95%) Position Integrity for ITP and Reference Aircraft ITP and Reference Aircraft data with horizontal position integrity bounds of 1.0 NM at 1×10E-05 Velocity Accuracy for ITP and Reference Aircraft ITP and Reference Aircraft data with horizontal velocity accuracies of at least 10 meters/second (m/s)
(19.4 kts), 95% Closing Mach Differential (Air Traffic Control (ATC) Crosscheck) Closing Mach Differential is less than or equal to
0.06 Mach
Appendix A A-13 Table A-2. Flightcrew Standardized Free Text Controller-Pilot Data Link Communication Message Set for In-Trail Procedure In-Trail Procedure (ITP) Type (number and relative position of reference aircraft) FREE TEXT Message Element Content 1 reference aircraft (ahead) “ITP [Distance] BEHIND [Aircraft flight identification (FLT ID)]” 1 reference aircraft (behind) “ITP [Distance] AHEAD OF [Aircraft FLT ID]” 2 reference aircraft (both ahead) “ITP [Distance] BEHIND [Aircraft FLT ID] AND [Distance] BEHIND [Aircraft FLT ID]” 2 reference aircraft (both behind) “ITP [Distance] AHEAD OF [Aircraft FLT ID] AND [Distance] AHEAD OF [Aircraft FLT ID]” 2 reference aircraft (one ahead and one behind) “ITP [Distance] BEHIND [Aircraft FLT ID] AND [Distance] AHEAD OF [Aircraft FLT ID]” To request an ITP climb or descent, the flightcrew will send a Controller-Pilot Data Link Communication (CPDLC) REQUEST CLIMB TO [altitude] or REQUEST DESCENT TO [altitude] message, as applicable, with the following verbiage added to FREE TEXT as listed in Table A-2:
Example of ITP request message: REQUEST CLIMB TO FL360 ITP 25 NM BEHIND SIA228 AND 21 NM AHEAD OF AFR008.
Note: This standardized free text message set will be used until an appropriate message set is implemented.
Appendix A A-14 Table A-3. Controller Free Text Controller-Pilot Data Link Communication Message Set for In-Trail Procedure In-Trail Procedure (ITP) Type (number and relative position of reference aircraft) FREE TEXT Message Element Content 1 reference aircraft (ahead) “ITP BEHIND [Aircraft flight identification (FLT ID)]” 1 reference aircraft (behind) “ITP AHEAD OF [Aircraft FLT ID]” 2 reference aircraft (both ahead) “ITP BEHIND [Aircraft FLT ID] AND BEHIND [Aircraft FLT ID]” 2 reference aircraft (both behind) “ITP AHEAD OF [Aircraft FLT ID] AND AHEAD OF [Aircraft FLT ID]” 2 reference aircraft (one ahead and one behind) “ITP BEHIND [Aircraft FLT ID] AND AHEAD OF [Aircraft FLT ID]” To grant an ITP request, the controller will send an uplink message containing CLIMB TO AND MAINTAIN [altitude] or DESCEND TO AND MAINTAIN [altitude] containing the text in Table A-3:
Example of ITP clearance message: ITP BEHIND SIA228 AND AHEAD OF AFR008 CLIMB TO FL360 REPORT LEVEL FL360.
Note 1: The controller should never issue an ITP clearance unless one has been requested by a flightcrew.
Note 2: This standardized free text message set will be used until an appropriate message set is implemented.
Appendix B B-1 APPENDIX B. CAVS USING ADS-B IN B.1 Purpose. This appendix describes Cockpit Display of Traffic Information (CDTI) Assisted Visual Separation (CAVS) and provides guidance to operators seeking FAA authorization to conduct CAVS operations.
B.2 Background. When a flightcrew accepts responsibility to maintain visual separation from another aircraft, they should maintain constant visual surveillance of that aircraft and notify air traffic control (ATC) if they can no longer do so. Additionally, the flightcrew accepts the responsibility for wake turbulence separation from that aircraft.
Though the weather must be visual meteorological conditions (VMC) pursuant to CAVS authorization, other environmental conditions may prevent them from maintaining constant visual surveillance of the traffic, such as when the traffic is landing toward a rising or setting sun. Additionally, distances and closure rate to an aircraft directly ahead can be difficult to judge, such that avoiding wake turbulence and getting too close to the traffic can be difficult.
B.3 CAVS Concept. CAVS is an ADS-B In application that assists the flightcrew in maintaining separation from ADS-B Out-equipped aircraft during visual separation.
Currently, CAVS authorization is only for the approach phase of flight when cleared by ATC to maintain visual separation from specific traffic. Because of the accuracy and integrity of displayed traffic on ADS-B In systems approved for CAVS, CAVS information may be used as a substitute for continuous visual observation of traffic-to-follow (TTF) under specified conditions. CAVS does not relieve the pilot of the responsibility to see and avoid other aircraft. ATC maintains separation responsibility from all other aircraft and for the orderly flow of traffic to the runway. Currently, there is no new phraseology associated with CAVS and approved for the use of CAVS. ATC will be unaware that a flightcrew is using CAVS. CDTI does not replace any traffic advisories (TA) and/or Resolution Advisories (RA) provided by the aircraft’s Airborne Collision Avoidance System (ACAS). RA response is still based on the ACAS display and approved procedures.
Note: See Appendix G, CDTI Assisted Separation on Approach, for a description of CDTI Assisted Separation on Approach (CAS-A).
B.4 CAVS Arrivals. Traffic information from the CDTI is used to augment out-the-window (OTW) visual contact with an aircraft a flightcrew is assigned to follow. This will enable them to accept separation responsibility from that aircraft. Once the flightcrew has visually acquired and accepted a visual approach clearance behind TTF, the pilot may use the lead aircraft traffic information on the CDTI as a means for maintaining separation while performing a visual approach. As done today with a visual approach clearance, no specific spacing assignments will be made by ATC. The procedure can be conducted behind all weight classes except when the lead aircraft is a super.
B.5 CAVS Description. Flightcrews are reminded that CAVS is a visual separation procedure. If at any time the traffic information provided by CAVS equipment becomes unreliable, inoperative, or distracting, its use should be discontinued immediately.
Appendix B B-2 Note 1: Although aircraft call signs are displayed on the CDTI, flightcrews should not use the call sign or Aircraft Identification (ACID) (flight identification (FLT ID)) of observed traffic in radio communications, as this could create confusion for both ATC and flightcrews monitoring the frequency.
Note 2: Flightcrews are not relieved of their duty to see and avoid.
Note 3: CAVS is currently restricted to maintaining visual separation from aircraft approaching the same landing runway.
B.5.1 CAVS Alerting. Installations compliant with Technical Standard Order (TSO)-C195b, Avionics Supporting Automatic Dependent Surveillance – Broadcast (ADS-B) Aircraft Surveillance Applications (ASA), or later revision, incorporate two unique alerting features: a caution level minimum range alert and an advisory level selectable range indication.
B.5.1.1 The selectable range indication alert is used to advise the flightcrew that the CAVS aircraft is at a predetermined range from the TTF. The range indication is set in accordance with individual established company procedures and is intended to assist the flightcrew in maintaining a safe distance from the TTF.
B.5.1.2 The caution level minimum range alert is activated when the range to the TTF is less than 0.42 nautical miles (NM), and can be issued on traffic that is within 1.4 NM under certain conditions. This alert cannot be modified by the flightcrew and indicates that, due to uncertainty in the ADS-B positions at such close ranges, the CDTI cannot safely be used to determine the position of the TTF.
B.5.2 Normal Procedures. CAVS normal procedures are as follows:
1. ATC points out TTF to the flightcrew of CAVS-equipped aircraft.
2. The CAVS flightcrew visually locates the traffic OTW and reports this to ATC.
3. ATC issues a clearance to “maintain visual separation” from the TTF.
4. If the TTF is broadcasting usable ADS-B Out information, the CAVS flightcrew correlates the TTF as seen OTW, with the traffic symbol of the TTF aircraft displayed on their aircraft’s CDTI and any information provided via ADS-B.
5. Once the flightcrew has correctly correlated the TTF on the CDTI, they designate the TTF target on the CDTI, and the avionics display the distance and groundspeed (GS) differential between TTF and own-ship. If CAVS is equipped with a selectable range indication alert, the flightcrew may set it in accordance with company procedures if it has not already been set.
6. Aided by this information, the CAVS flightcrew can more easily maintain visual contact with the TTF and manage their distance and closure.
7. The CAVS aircraft maintains VMC at all times. However, if the flightcrew should lose OTW contact with the TTF, the approach may continue using the CDTI (and
Appendix B B-3 ADS-B Guidance Display (AGD), if one is installed) to maintain visual separation using the CAVS information alone.
B.5.3 Maneuver Termination. CAVS is intended to assist the flightcrew in maintaining pilot-applied visual separation. The loss of CAVS information does not itself require discontinuing visual separation, provided OTW visual contact with the TTF and safe separation can be maintained. Discontinue using CAVS as a substitute for OTW visual contact under any of the following conditions:
1. The flightcrew is unable to maintain VMC.
2. AGD (if installed) fails and OTW visual contact cannot be maintained.
3. AGD (if installed) information conflicts with the CDTI information to the extent that it becomes a distraction, is confusing to the pilots, or raises a concern about the safety of the procedure.
4. Sustained loss of ADS-B data quality and/or integrity as indicated to the pilot via the displays.
5. The caution level minimum range alert is activated.
6. If the flightcrew is unable to maintain a safe distance for any reason, they must immediately advise ATC and request further clearance.
B.6 CAVS System. The CAVS authorization requires an aircraft to have an installed ADS-B In system that meets the standards of TSO-C195b or later revision, or a system approved by the Administrator intended for use in CAVS. For guidance on the installation of ADS-B Out equipment, refer to AC 20-165, Airworthiness Approval of Automatic Dependent Surveillance - Broadcast OUT Systems, and AC 20-172, Airworthiness Approval for ADS-B In Systems and Applications.
B.7 Authorization to Conduct CAVS. FAA authorization is required for all U.S. aircraft operators to conduct CAVS operations using ADS-B In (14 CFR § 119.49(a)(5)). This appendix provides guidance to operators on the process for requesting issuance of this authorization, including guidance on the documentation that should be submitted.
Note 1: For FAA authorization, refer to FAA Order 8900.1, Volume 3, Chapter 18, Section 3, Operations Specification (OpSpec)/Management Specification (MSpec)/Letter of Authorization (LOA) A355, Automatic Dependent Surveillance-Broadcast (ADS-B) In Operations.
Note 2: Operators may already hold other ADS-B In authorizations. There is no need to submit documentation for a CAVS authorization if that documentation has already been submitted for previous ADS-B In authorizations. The CAVS application may include references to those duplicate documents instead.
B.7.1 Initial Request for Authorization. U.S. aircraft operators seeking to conduct CAVS should first contact their assigned FAA office to indicate their intent. At the time of the
Appendix B B-4 operator’s initial request, the FAA will provide the operator with a CAVS Application Checklist, which should be completed with attached supporting documents.
B.7.2 Documentation to Submit With Formal Request.
B.7.2.1 Documentation Guidance. This section describes the documentation required for submission of a formal CAVS proposal. The operator’s assigned principal inspector (PI) may ask for additional information based on any unique aspects of their specific operation. The operator should submit a letter of request for issuance of authorization to the assigned PI. The letter of request should include the following information:
• Type of aircraft (make, model, and series (M/M/S)).
• List of aircraft registration numbers (N-number) associated with the request for authorization.
• ADS-B equipment complies with TSO-C195b or later revision, or as approved for CAVS by the Administrator.
• Installation has been completed following guidance contained in AC 20-172, or other acceptable means.
• Name of the ADS-B In (CAVS) software manufacturer and applicable software version(s).
B.7.2.2 Airplane Flight Manual (AFM) Compliance Documentation. Operators will submit documentation that demonstrates applicable aircraft have an ADS-B In system that meets the performance standards of TSO-C195b or later revision, or as otherwise approved by the Administrator, for CAVS operations.
B.7.2.3 Operation Manuals and Checklists. The certificate holder (CH)/operator/program manager (as applicable) should submit information
(e.g., Airplane Operations Manual (AOM) bulletin or equivalent) to the flightcrews describing ADS-B, to include:
• CAVS system description;
• Normal procedures; and
• Non-normal or contingency procedures.
B.7.2.4 Maintenance. See Appendix C, ADS-B In Operations—Aircraft Qualification and Maintenance, for applicable maintenance guidance.
B.7.2.5 Revision of Minimum Equipment List (MEL). See Appendix C for guidance on the necessary MEL documents to be submitted for authorization of CAVS.
Appendix B B-5 B.7.2.6 Pilot Training. Submit applicable portions of proposed CAVS-specific pilot training material and include a description of the methods used to conduct, evaluate, and manage the training. The CAVS pilot training should include:
1. ADS-B Out/In system overview (if not previously addressed with another ADS-B application).
2. ADS-B CAVS system operations.
3. CAVS normal procedures:
• Visual separation procedures.
• Speed management.
• Assessing closure rates.
• Wake turbulence avoidance.
• Weather minimums.
• Use of and response to the selectable CAVS range alert.
• Crew coordination during CAVS.
4. CAVS MEL procedures (as applicable).
5. CAVS equipment limitations.
6. CDTI interface.
7. Contingency procedures.
Appendix C C-1 APPENDIX C. ADS-B IN OPERATIONS—AIRCRAFT QUALIFICATION AND
MAINTENANCE C.1 Purpose. This appendix provides guidance on aircraft qualification, maintenance, and maintenance personnel training associated with authorization of ADS-B In operations.
C.2 Applicability. The ADS-B In aircraft qualification and maintenance guidance contained herein applies to operations conducted under 14 CFR parts 91, 91 subpart K (14 CFR part 91K), 121, 125 (including 14 CFR part 125 Letter of Deviation Authority (LODA)), 129, and 135. Title 14 CFR part 91 operators (excluding 14 CFR part 91K operators) should comply with the guidance contained in this appendix. Operators conducting operations under 14 CFR parts 91K, 121, 125 (including 14 CFR part 125 LODA), 129, and 135 should address all aspects of the guidance contained in this appendix when submitting requests for authorization of ADS-B In operations.
C.3 Aircraft Qualification.
C.3.1 ADS-B In systems must meet the standards of the appropriate Technical Standard Order (TSO)-C195b, Avionics Supporting Automatic Dependent Surveillance – Broadcast (ADS-B) Aircraft Surveillance Applications (ASA), or later revision, for authorization.
Guidance on the installation of ADS-B Out equipment can be found in AC 20-165, Airworthiness Approval of Automatic Dependent Surveillance - Broadcast OUT Systems. Guidance on the installation of ADS-B In systems can be found in AC 20-172, Airworthiness Approval for ADS-B In Systems and Applications.
C.3.2 Applications submitted to the FAA for authorization to conduct ADS-B In operations should contain the following documentation to demonstrate aircraft qualification:
1. Applicable ADS-B In airworthiness documentation in the form of an aircraft type certificate (TC), amended TC, or Supplemental Type Certificate (STC).
2. ADS-B In avionics manufacturer’s instructions for continued airworthiness (ICA), as accepted by the FAA.
3. Proposed minimum equipment list (MEL) revisions, if applicable, listing all limitations and procedures associated with the dispatch of aircraft with the ADS-B In system inoperative.
C.4 Maintenance.
C.4.1 Maintenance of ADS-B In systems should comply with the guidance contained in this paragraph and must comply with applicable airworthiness regulations. Maintenance personnel should be familiar with the operator’s ADS-B In system maintenance procedures, their individual responsibilities with respect to those procedures, and the availability of any resources within or outside of the maintenance organization necessary to ensure the continued airworthiness of the ADS-B In system.
Appendix C C-2 C.4.2 Applications submitted for authorization to conduct ADS-B In operations under 14 CFR parts 91, 91K, 121, 125 (including 14 CFR part 125 LODA), 129, and 135 should include documentation that includes the following, as applicable:
1. The General Maintenance Manual (GMM) and, for 14 CFR part 125, the Policy and Procedures Manual (PPM) should incorporate the ADS-B In manufacturer’s ICA, as accepted by the FAA, and identify any special techniques, maintenance/inspection frequencies, and test equipment used to support the continued airworthiness of the system.
2. Indicate whether ADS-B In system maintenance is integrated into an existing approved maintenance program or is a separate program.
3. Identify the GMM or PPM revision and update procedures, if not previously approved.
4. Identify how maintenance personnel will be trained on the ADS-B In system and the method to record and maintain any associated qualifications.
5. Procedures for ADS-B In software installation, updates, evaluations, tests, and configuration control.
6. Procedures used to make modifications, additions, and changes to the ADS-B In system.
7. Procedures for ADS-B In discrepancy reporting and recording.
8. MEL and logbook procedures for deferral of the ADS-B In system or components of the system.
9. Notification procedures between maintenance control, engineering, flight operations, and dispatch (or equivalent) when the ADS-B In system is deferred.
10. Procedures to monitor and identify ADS-B In-equipped aircraft with chronic discrepancies and restrict the aircraft from ADS-B In operations until appropriate corrective action and verification tests have been performed.
11. Procedures for return to service of the ADS-B In system following routine/nonroutine maintenance or completion of corrective action on an aircraft flagged for chronic discrepancies.
12. Integration of ADS-B In maintenance into existing quality control (QC) and quality assurance (QA) programs, as applicable.
C.5 Maintenance Personnel Training.
C.5.1 General. This paragraph contains guidance on maintenance personnel training associated with ADS-B In operations. Operators should address this guidance, as applicable, in proposals submitted to the FAA for authorization to conduct ADS-B In operations.
C.5.2 Maintenance Training. Maintenance personnel should be knowledgeable of the guidance contained in this AC and applicable regulations. Operator and contract maintenance personnel, including mechanics, maintenance controllers, avionics technicians, and
Appendix C C-3 inspection/QA personnel, should receive initial and recurrent training (as necessary) to establish and maintain an effective ADS-B In maintenance program.
C.5.3 Application Submissions. Applications submitted for authorization to conduct ADS-B In operations should address the following:
1. Identify the person(s) responsible for ensuring ADS-B In maintenance and inspection personnel are properly trained, knowledgeable, and current in accordance with the GMM or PPM, as appropriate.
2. Identify how the ADS-B In training will be conducted (i.e., in-house or outside training provider).
3. Include policy and procedures that address any qualifications for ADS-B In maintenance and inspection personnel.
4. Identify the methods and techniques used to conduct initial and recurrent training
(e.g., Instructor-Led Training (ILT), computer-based training (CBT), and on-the-job training (OJT)).
5. Identify the procedures used to record and maintain initial and recurrent ADS-B In training and qualifications.
6. Include maintenance and inspection training curriculum that addresses the following ADS-B In topics:
• Operational overview;
• Aircraft system overview;
• Maintenance and inspection procedures;
• Personnel training qualifications (as applicable);
• MEL procedures;
• Test equipment and use (as applicable); and
• Return to service test procedures.
Appendix D D-1 APPENDIX D. DEFINITIONS The terms have the following meaning when used in this AC:
D.1 Automatic Dependent Surveillance-Broadcast (ADS-B) Airspace. The airspace specified in 14 CFR § 91.225.
D.2 Automatic Dependent Surveillance-Broadcast (ADS-B) Guidance Display (AGD).
The AGD provides digital readouts and alerts of time-sensitive information located on the Cockpit Display of Traffic Information (CDTI). This is used primarily for installations where the CDTI is not installed in the forward field of view (FOV).
D.3 Automatic Dependent Surveillance-Broadcast (ADS-B) In. ADS-B In is the receipt, processing, and display of ADS-B transmissions. ADS-B In is necessary to utilize ADS-B traffic and broadcast services (e.g., Flight Information Service-Broadcast (FIS-B) and Traffic Information Service-Broadcast (TIS-B)).
D.4 Automatic Dependent Surveillance-Broadcast (ADS-B) Out. Transmission of an aircraft’s position, altitude, velocity, and other information to other aircraft and air traffic control (ATC) surveillance systems.
D.5 Automatic Dependent Surveillance-Rebroadcast (ADS-R). ADS-R is a link-translation and rebroadcast function of the ADS-B ground system that allows both ADS-B frequencies (1090 megahertz (MHz) and 978 MHz) to share information.
D.6 Cockpit Display of Traffic Information (CDTI). This is a generic display that provides the flightcrew with surveillance information about other aircraft, including position.
Traffic information may be obtained from one or multiple sources, including ADS-B, Airborne Collision Avoidance System (ACAS), and TIS-B. The display of information may be hosted on an Electronic Flight Bag (EFB) or the aircraft’s integrated avionics suite.
D.7 Cockpit Display of Traffic Information (CDTI) Assisted Separation on Approach (CAS-A). CAS-A is an operation that builds on the existing CDTI Assisted Visual Separation (CAVS) operation, as described in Appendix B, CAVS Using ADS-B In, and uses the same flight deck avionics as required for CAVS. CAS-A is initiated by the controller, who provides a CAS-A designation instruction that includes the flight identification (FLT ID) for the traffic-to-follow (TTF). The flightcrew identifies the TTF on the CDTI using the FLT ID provided by the controller (visual acquisition is not required).
D.8 Cockpit Display of Traffic Information (CDTI) Assisted Visual Separation (CAVS).
CAVS is an ADS-B In application that assists the flightcrew in maintaining visual separation from ADS-B Out-equipped aircraft.
D.9 Extended Squitter (ES). ES is how ADS-B messages are transmitted from a Mode Select (Mode S) transponder. ES is a long message (e.g., format DF=17) that