U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Automatic Dependent Surveillance-Broadcast (ADS-B) Operations Date: 9/21/12 Initiated by: AFS-400 AC No: 90-114 Change: 1
1. PURPOSE. The intent of this advisory circular (AC) is to facilitate operations using Automatic Dependent Surveillance-Broadcast (ADS-B) technology in compliance with Title 14 of the Code of Federal Regulations (14 CFR) part 91, §§ 91.225 and 91.227, which are required after January 1, 2020.
2. PRINICIPAL CHANGES. This change creates a new Appendix 2, Automatic Dependent Surveillance-Broadcast (ADS-B) In-Trail Procedure (ITP). Preexisting Appendices 2 and 3 are now renumbered to 3 and 4.
PAGE CHANGE CONTROL CHART Remove Pages Dated Insert Pages Dated Page 1 12/8/11 Page 1 9/21/12 iii 12/8/11 iii 9/21/12 iv 12/8/11 iv 9/21/12 --- Appendix 2 9/21/12 Appendix 2 12/8/11 Appendix 3 9/21/12 Appendix 3 12/8/11 Appendix 4 9/21/12
ORIGINAL SIGNED by
/s/ John M. Allen Director, Flight Standards Service
U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Automatic Dependent Surveillance-Broadcast (ADS-B) Operations Date: 9/21/12 Initiated by: AFS-400 AC No: 90-114 Change: 1 The Federal Aviation Administration (FAA) has issued a new rule contained in Title 14 of the Code of Federal Regulations (14 CFR) part 91, §§ 91.225 and 91.227. This rule requires Automatic Dependent Surveillance-Broadcast (ADS-B) OUT performance when operating in designated classes of airspace within the U.S. National Airspace System (NAS) after January 1, 2020. This advisory circular (AC) provides users of the NAS guidance on a means of conducting flight operations in accordance with §§ 91.225 and 91.227. The Aeronautical Information Manual (AIM) provides an overview of, and the appendices in this AC provide guidance for, additional operations enabled by ADS-B. Appendix 3 contains a list of ADS-B-related definitions.
Comments and suggestions for improving this publication should be directed to:
AFS ADS-B Branch (AFS-406) 470 L’Enfant Plaza East Suite 4102 Washington, DC 20024
CONTENTS Paragraph Page CHAPTER 1. ADS-B OPERATIONS
1-1. Purpose1
1-2. Audience1
1-3. Scope1
1-4. Cancellation1
CHAPTER 2. OVERVIEW AND SYSTEM DESCRIPTION
2-1. Overview3
2-2. ADS-B System Description3
2-3. ADS-B Broadcast Services4
CHAPTER 3. OPERATIONAL CONSIDERATIONS
3-1. U.S. ADS-B Airspace and Equi pment Performance Requirements5
Figure 1, Automatic Dependent Surveillance-Broadcast Airspace Rule (§ 91.225)
Diagram6
3-2. Exceptions to Airspace Requirements6
CHAPTER 4. OPERATING PROCEDURES
4-1. General Operating Procedures7
4-2. Operator Familiarity of the Installed ADS-B System7
4-3. ADS-B Equipment Operations (U.S.-Designated Airspace)7
4-4. Flight Plans8
4-5. Preflight Requirements (U.S.- Designated Airspace) (Reserved)8
4-6. Flightcrew Entry of Required ADS-B Data8
APPENDIX 1. ADS-B OUT OPERATIONS OUTSIDE OF U.S.-DESIGNATED
AIRSPACE (8 pages)1
Table 1. Canadian-Specific Surveillance Phraseology6
Table 2. Australian-Specific Surveillance Phraseology7
APPENDIX 2. AUTOMATIC DEPENDENT SURVEILLANCE-BROADCAST (ADS-B)
IN-TRAIL PROCEDURE (ITP) (14 pages)1
Figure 1. Reduction of Aircraft Separati on Minima with In-Trail Procedure1
Figure 2. In-Trail Procedur e Distances Illustrated3
Figure 3. Similar Track4
Figure 4. In-Trail Procedure Climb/Descent Variations7
Table 1. In-Trail Procedure Initiation/Maneuver Criteria (Reference RTCA DO 312) ...12 Table 2. Flightcrew Free Text Controller-Pilot Data Link Communication Message Set
for In-Trail Procedure13
Table 3. Controller Free Text Controller -Pilot Data Link Communication Message Set
for In-Trail Procedure14
APPENDIX 3. DEFINITIONS (4 pages)1
APPENDIX 4. RELATED REGULATIONS AND READING MATERIAL (4 pages)1
Par 1-1 Page 1 (and 2) CHAPTER 1. ADS-B OPERATIONS
1-1. PURPOSE. The intent of this advisory circular (AC) is to facilitate operations using Automatic Dependent Surveillance-Broadcast (ADS-B) technology in compliance with Title 14 of the Code of Federal Regulations (14 CFR) part 91, §§ 91.225 and 91.227, which are required after January 1, 2020.
1-2. AUDIENCE. This AC applies to all U.S. operators intending to use ADS-B.
1-3. SCOPE. This AC contains an overview of the ADS-B system and general operating procedures associated with operations conducted in compliance with the airspace and performance requirements of §§ 91.225 and 91.227. The appendices provide guidance for additional operations enabled by ADS-B.
a. Obligation. The information contained in this AC is not mandatory; it describes an acceptable means but not the only means of complying with the applicable regulations. This AC does not change, create, amend, or permit deviation from any regulatory requirement.
b. Authorization to Conduct ADS-B OUT Operations. There is no authorization required by the Federal Aviation Administration (FAA) to conduct ADS-B OUT operations in the airspace specified in § 91.225 (U.S.-designated airspace).
c. Certification and Installation of ADS-B OUT Equipment.
(1) Guidance associated with the installation and airworthiness approval of ADS-B OUT equipment is contained in AC 20-165, Airworthiness Approval of Automatic Dependent Surveillance-Broadcast (ADS-B) OUT Equipment for Operation in the National Airspace System (NAS).
NOTE: Outside the U.S. National Airspace System (NAS), many worldwide air traffic service providers (ATSP) allow the use of ADS-B equipment certified to the European Aviation Safety Agency (EASA) Acceptable Means of Compliance (AMC) 20-24, Certification Considerations for the Enhanced ATS in Non-Radar Areas using ADS-B Surveillance (ADS-B-NRA) Application via 1090 MHz Extended Squitter, dated February 5, 2008.
NOTE: ADS-B equipment installed in accordance with AC 20-165 (TSO-C166b and TSO-C154c) meets the equipment requirements of AMC 20-24. However, AMC 20-24 equipment does not comply with § 91.225.
(2) Until further notice, ADS-B OUT equipment must be installed in accordance with the Flight Standards Service (AFS)/Aircraft Certification Service (AIR) memorandum, Approval for ADS-B OUT Systems. A copy of this memorandum can be obtained from the FAA Regulatory and Guidance Library (RGL) Web site at http://rgl.faa.gov.
1-4. CANCELLATION. This AC and AC 20-165 cancel AC 120-86, Aircraft Surveillance Systems and Applications, dated September 16, 2005.
Par 2-1 Page 3 CHAPTER 2. OVERVIEW AND SYSTEM DESCRIPTION
2-1. OVERVIEW. To accommodate the ever-growing demands placed on the NAS, limitations associated with the current system must be overcome. Beginning with the NAS-wide implementation of ADS-B, the FAA has begun a transformation to both overcome existing limitations and to enable the improvements needed to increase the capacity and efficiency of the NAS while maintaining safety. ADS-B supports these improvements by providing a higher update rate and enhanced accuracy of surveillance information over the current radar-based surveillance systems. In addition, ADS-B enables the expansion of air traffic control (ATC) surveillance services into areas where none existed previously. The ADS-B ground system also provides Traffic Information Service-Broadcast (TIS-B) and Flight Information Service-Broadcast (FIS-B) for use on appropriately equipped aircraft, enhancing the user’s situational awareness (SA) and improving the overall safety of the NAS.
2-2. ADS-B SYSTEM DESCRIPTION.
a. ADS-B System Architecture. The ADS-B system architecture is composed of aircraft avionics and a ground infrastructure. Onboard avionics determine the position of the aircraft, typically by using the Global Navigation Satellite Systems (GNSS) and transmitting this and additional information about the aircraft to ground stations for use by ATC; to ADS-B-equipped aircraft; and to other aviation service providers.
b. ADS-B Operating Frequencies. In the United States, the ADS-B system operates on two frequencies: 1090 or 978 megahertz (MHz). See Chapter 3, Figure 1, Automatic Dependent Surveillance-Broadcast (ADS-B) Airspace Rule (§ 91.225) Diagram, for airspace and frequency requirements.
(1) 1090 MHz Frequency. The 1090 MHz frequency is associated with current Mode A, C, and S transponder operations. ADS-B information is included in Mode S transponders’ Extended Squitter (ES) transmit messages, and referred to as 1090ES in this AC.
(2) 978 MHz Frequency. ADS-B equipment operating on 978 MHz are referred to as Universal Access Transceivers (UAT) in this AC.
c. ADS-B Avionics Operating Modes. ADS-B avionics can have the ability to both transmit and receive information.
(1) ADS-B OUT. The transmission of ADS-B information from aircraft is known as ADS-B OUT.
(2) ADS-B IN. The receipt of ADS-B information by an aircraft is known as ADS-B IN.
NOTE: After January 1, 2020, all aircraft operating within the airspace defined in § 91.225 will be required to transmit (ADS-B OUT) the information defined in § 91.227 using Technical Standard Order (TSO)- C166b or TSO-C154c avionics.
Page 4 Par 2-3
2-3. ADS-B BROADCAST SERVICES. ADS-B implementation includes three broadcast services: Automatic Dependent Surveillance-Rebroadcast (ADS-R), TIS-B, and FIS-B.
a. ADS-R. Because the ADS-B system operates on two separate frequencies (1090 MHz and 978 MHz), there is a need to translate, reformat, and rebroadcast the information from each frequency to enable aircraft operating on the alternate frequency to process and use the other’s information. This process is referred to as ADS-R and occurs within the ADS-B ground station.
NOTE: Aircraft operating on the same ADS-B frequency exchange information directly and do not require ADS-R translation. Aircraft with ADS-B IN capability on both UAT and 1090ES do not require ADS-R service.
b. TIS-B. TIS-B is the broadcast of transponder-based traffic information derived from ATC surveillance systems. TIS-B provides ADS-B-IN-equipped aircraft with a more complete picture of surrounding traffic in situations where not all aircraft are equipped with ADS-B.
c. FIS-B. The FIS-B operates on UAT only and provides ADS-B-IN-equipped aircraft with a suite of advisory-only aeronautical and weather information products to enhance the user’s SA. Additional information on FIS-B and the products available through the service are provided in the Aeronautical Information Manual (AIM).
Par 3-1 Page 5 CHAPTER 3. OPERATIONAL CONSIDERATIONS
3-1. U.S. ADS-B AIRSPACE AND EQUIPMENT PERFORMANCE REQUIREMENTS.
After January 1, 2020, unless authorized by ATC, all aircraft operating in the airspace specified in § 91.225 must meet the equipment performance requirements defined in § 91.227. This chapter describes both the airspace and equipment performance requirements of §§ 91.225 and 91.227. Operators should consider the need to access ADS-B-required airspace and the performance requirements of that airspace when equipping for compliance with §§ 91.225 and 91.227.
a. Inside Class A Airspace. Operations in Class A airspace must:
(1) Meet the equipment requirements in TSO-C166b (1090ES); and
(2) Meet the equipment performance requirements of § 91.227.
NOTE: Although TSO-C166b incorporates standards for TIS-B equipment, TIS-B equipage (ADS-B IN) is not required for compliance with §§ 91.225 and 91.227.
b. Outside Class A Airspace. Operations outside Class A airspace must:
(1) Meet the equipment performance requirements of § 91.227;
(2) Meet the requirements in TSO-C166b (1090ES); or
(3) Meet the requirements in TSO-C154c in the following airspace:
(a) Class B and Class C airspace;
(b) Except as provided for in § 91.225(e), within 30 nautical miles (NM) of an airport listed in part 91 appendix D (Mode C veil), section 1, from the surface upward to 10,000 feet mean sea level (MSL);
(c) Above the ceiling and within the lateral boundaries of a Class B or Class C airspace designated for an airport upward to 10,000 feet MSL;
(d) Except as provided for in § 91.225(e), Class E airspace within the 48 contiguous United 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 (i.e., mountainous areas); and
(e) 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 NM.
Page 6 Par 3-1 FIGURE 1. AUTOMATIC DEPENDENT SURVEILLANCE-BROADCAST AIRSPACE RULE (§ 91.225) DIAGRAM
3-2. EXCEPTIONS TO AIRSPACE REQUIREMENTS. The requirements of § 91.225(b) do not apply to any aircraft that was not originally certified with an electrical system or that has not subsequently been certified with such a system installed, including balloons and gliders. These aircraft may conduct operations without ADS-B OUT in the airspace specified in § 91.225(d)(2) and (4). While the requirements do not apply to these aircraft, the aircraft operator requires the approval of ATC before entering ADS-B-required airspace. Operations specified in § 91.225(d)(2) must be conducted:
• Outside any Class B or Class C airspace, and
• Below the altitude of the ceiling of a Class B or Class C airspace designated for an airport, or 10,000 feet MSL, whichever is lower.
Par 4-1 Page 7 CHAPTER 4. OPERATING PROCEDURES
4-1. GENERAL OPERATING PROCEDURES. This chapter describes the general procedures for ADS-B OUT operations in accordance with § 91.225. All operators should use this information when planning and conducting operations requiring ADS-B OUT performance.
4-2. OPERATOR FAMILIARITY OF THE INSTALLED ADS-B SYSTEM.
a. System Operation Familiarity. All operators should use the applicable Airplane Flight Manual (AFM), Airplane Flight Manual Supplement (AFMS), Rotorcraft Flight Manual (RFM), Rotorcraft Flight Manual Supplement (RFMS), pilot’s operating handbook (POH), or other required operating handbooks or manuals, to become familiar with the proper operation of the installed ADS-B system and any procedures expected of the user for indications of reduced performance or failures within the system.
b. Understanding Failure Indicators within the System. Because many ADS-B system installations will be upgrades to existing transponders (Mode S), there may be limited ability to indicate ADS-B failures. Mode S transponders with ADS-B functionality may indicate a device failure (loss of transponder/ADS-B) and input failures (loss of position source, such as GNSS) with the same indicator light. Operators should refer to their AFM, AFMS, RFM, RFMS, POH, and other handbooks and manuals for information on the differences between device failures and function failures, and the implications and procedures associated with each failure type.
c. Transponder Operation and ADS-B Transmissions. For ADS-B system installations integrated within a transponder that share control features, operators should be aware that disabling the transponder may also disable ADS-B transmissions, resulting in a loss of Secondary Surveillance Radar (SSR) services and Traffic Alert and Collision Avoidance System (TCAS)/TCAS II operation, if so equipped.
4-3. ADS-B EQUIPMENT OPERATIONS (U.S.-DESIGNATED AIRSPACE).
a. Transmit Requirements. In accordance with § 91.225(f), each person operating an aircraft equipped with ADS-B OUT must operate this equipment in the transmit mode at all times. This equipment operation requirement pertains to all phases of flight operation, including airport surface movement area operations. For ADS-B installations integrated within a transponder, the flight manual, checklists, and any operator’s procedures manuals must be updated accordingly with proper ADS-B system operations guidance.
NOTE: Aircraft must comply with the appropriate TSO requirements when transmitting ADS-B data.
b. ATC-Authorized Deviations. Requests for ATC-authorized deviations from the requirements in § 91.225(g) must be made to the ATC facility that has jurisdiction over the concerned airspace or airport movement area and be made within the time periods specified below:
Page 8 Par 4-3
(1) For operation of an aircraft with inoperative ADS-B equipment to the airport of ultimate destination (including any intermediate stops) to proceed to a place where suitable repairs can be made, or both, the request may be made at any time.
(2) For operation of an aircraft that is not equipped with ADS-B, the request must be made at least 1 hour before the proposed operation.
4-4. FLIGHT PLANS. When operating aircraft equipped with ADS-B OUT, operators should indicate their ADS-B capability on the flight plan as “RMK/ADSB.”
4-5. PREFLIGHT REQUIREMENTS (U.S.-DESIGNATED AIRSPACE). Reserved.
4-6. FLIGHTCREW ENTRY OF REQUIRED ADS-B DATA. Operational procedures shall be developed by the operator to address flightcrew entry of the ADS-B message elements required in § 91.227 and as described in subparagraphs 4-6a through d. If the ADS-B avionics system design does not allow for a single point of entry for this information, the AFM/AFMS/RFM/RFMS/POH or other required flight manual must address the requirement to enter the information multiple times through the appropriate system’s interface and to ensure that conflicting aircraft identification information is not transmitted to ATC.
a. Mode A Code.
(1) ATC automation relies on the Mode A code to identify aircraft under radar surveillance and to correlate the displayed target to a flight plan. The Mode A code is one element of the transmitted ADS-B message set. Because SSR and ADS-B surveillance will overlap in much of the NAS, correlation of the Mode A code between the transponder and the ADS-B message is necessary to ensure that a single target is resolved and correlated to a flight plan route.
(2) It is imperative that the ATC-assigned transponder code is identical to the one in the ADS-B OUT message. A preferable design configuration is one that provides the pilot a single point of entry for the Mode A code in both the transponder and the ADS-B OUT avionics. If there is no single point of entry provided for the Mode A code into the transponder, then the AFM or operating handbook must address the requirement to enter the Mode A code into both systems separately.
NOTE: Transmission of conflicting transponder and ADS-B Mode A codes will result in erroneous traffic conflict alerts within the ATC automation system.
b. Aircraft’s Call Sign/Flight ID.
(1) The AFM or POH should provide specific instructions for entering the registration number or flight plan call sign, sometimes referred to as the flight ID. The term “aircraft call sign” means the radiotelephony call sign assigned to an aircraft for voice communications purposes. For General Aviation (GA) aircraft, the aircraft call sign is normally associated with the aircraft registration number (tail number) and may be preset. For airline and commuter aircraft, it is usually composed of the company name and flight number (and therefore not linked