40 Note: Upgrading a previously installed and approved TSO-C112() Mode S transponder to include ADS-B functionality does not require transmit power testing unless a new antenna has been installed, the antenna location has changed, or the output specifications on the transponder have changed.
4.1.11.1 1090ES Transmitter.
Verify that the peak pulse power at the antenna end of the transmission line meets the minimum and maximum power levels summarized in Table 3, considering the test equipment antenna gain and path loss.
Repeat the measurement in each quadrant of the antenna pattern (forward, aft, left, right).
Table 3. Minimum and Maximum Transmitted Power From TSO-C166b Tested Transmitter Class Minimum Power Maximum Power A1 21.0 dBW 27.0 dBW A1S 21.0 dBW 27.0 dBW B1 21.0 dBW 27.0 dBW B1S 21.0 dBW 27.0 dBW A2 21.0 dBW 27.0 dBW A3 23.0 dBW 27.0 dBW
4.1.11.2 UAT Transmitter.
Verify that the peak pulse power at the antenna end of the transmission line meets the minimum and maximum power levels summarized in Table 4, considering the test equipment antenna gain and path loss.
Repeat the measurement in each quadrant of the antenna pattern (forward, aft, left, right).
Table 4. Minimum and Maximum Transmitted Power From TSO-C154c Tested Transmitter Class Minimum Power Maximum Power A1H 12.0 dBW 16.0 dBW A1S 12.0 dBW 16.0 dBW B1 12.0 dBW 16.0 dBW B1S 12.0 dBW 16.0 dBW A2 12.0 dBW 16.0 dBW A3 20.0 dBW 24.0 dBW
4.1.12 TCAS.
If a TCAS II system is installed on the aircraft, ensure the proper messages are transmitted by the ADS-B system when the TCAS II is on and operating in a mode that can provide RAs. No TCAS II system regression testing beyond the ground interface testing covered in this section is required.
4.1.13 Transponder All-call Inhibit.
When ADS-B functionality resides in a Mode S transponder, conduct a test demonstrating that replies to Mode A/C/S all-call and Mode S-only all-call interrogations are inhibited on the ground. Also demonstrate that replies to discrete interrogations are not inhibited.
4.1.14 Mode 3/A Code and Emergency Code.
Demonstrate that the correct Mode 3/A code and IDENT is transmitted. Do not transmit the 7500, 7600, or 7700 emergency codes over the air during ground or flight testing. If testing emergency codes is desired, contact the local ATC facility and coordinate testing to prevent a nuisance emergency response.
4.2 Flight Test.
This section provides information on flight testing ADS-B systems.
4.2.1 Electromagnetic Interference.
During all phases of flight, survey the flight deck EMI to determine that the ADS-B OUT equipment is not a source of objectionable conducted or radiated interference to previously installed systems or equipment, and that operation of the ADS-B OUT equipment is not adversely affected by conducted or radiated interference from previously installed systems and equipment.
4.2.2 Other System Performance.
Demonstrate the proper performance of any previously installed aircraft systems that required changes as a result of the ADS-B installation in accordance with the applicable policy. This can be accomplished with standard regression test procedures for the other installed systems, and does not require a unique test for ADS-B.
4.2.3 User Interface.
Exercise all user inputs. If separate user inputs are required for the transponder and ADS-B systems, evaluate the flight manual procedures for ensuring the same Mode 3/A code, IDENT, and emergency codes are transmitted from both systems.
4.3 Flight Test With FAA Ground System.
Perform a flight test to show that the installed system performs properly with the FAA ground system. The test will verify that the FAA ground system properly receives the aircraft’s ADS-B broadcast messages, there are no dropouts, and the information transmitted is complete and correct. Currently the only method available to accomplish
42 the flight test is to fly within ADS-B service coverage and accomplish a post-flight analysis of the data received from the FAA. This test is intended to evaluate the design interface for the position source and the ADS-B equipment.
Note 1: This flight test is intended to complete a design approval under an STC or TC application; it is not intended for the alteration of individual aircraft.
Note 2: Follow your standard process for requesting flight test authorization; there are no unique flight test authorization requirements for ADS-B flight tests.
4.3.1 Preflight Coordination.
4.3.1.1 Data Retrieval.
Flight test data can be requested for two distinct types of flight testing, operational checkout of a previously certified system, and testing of a first-of-kind ADS-B system.
4.3.1.1.1 Previously Certified Systems.
In the context of this AC, a previously certified system is an ADS-B system that holds a Type Certificate, Supplemental Type Certificate or is listed on an Approved Model Listing. Aircraft owners may request a flight test compliance report to verify a previously approved ADS-B system has been installed and configured correctly. Interested parties can email 9-AWA-AFS-300-ADSB-AvionicsCheck@faa.gov and request an ADS-B Aircraft Operation Compliance Report (ACR). When requesting an ACR, include aircraft registration number (“N” number), location, date, and approximate local time of flight. All requests should be made after the test flight has taken place.
4.3.1.1.2 First-of-Kind Systems.
System integration teams may request flight test data for first-of-kind ADS-B systems. First-of-kind systems are those that are part of a TC, STC, or Approved Model List (AML) effort. At least 48 hours before the flight, notify the FAA by emailing 9-avs-air-130flttest@FAA.gov that you require data to support first-of-kind testing of a new ADS-B system.
Contacting the FAA before a test flight will better ensure flight test data will be provided in a timely manner. Upon initial contact, the FAA will provide a flight test request sheet. When contacting the FAA for flight test data, it is recommended you carbon copy any certifying officials you may be working with within the Aircraft Certification Office, Military Certification Office, Flight Standards District Office, or Flight Inspection District Office. Flight test data can usually be provided to the requester within 48 hours. An analysis report may take up to 30 days if it is determined necessary.
4.3.1.2 ATC Coordination.
There is no ADS-B specific requirement to coordinate the flight test in advance with ATC. Follow normal flight test procedures for coordinating with ATC.
4.3.2 Flight Test Profile.
This profile is intended to be flown on all ADS-B system approvals. The profile need not be flown exactly, and variances for ATC clearances and vectors are acceptable. The flight test should be at least 1 hour long. If the profile is completed in less than 1 hour, continue the flight until enough data is collected. The flight test may not be performed using the random UAT 24-bit address feature, since the 24-bit address is a key field in retrieving the ATC flight profile data. The profile discussed in section 4.3.2.3 through
4.3.4.6 below may be flown in any order.
4.3.2.1 Location of Flight.
The flight may be accomplished in any airspace that has FAA ADS-B ground station coverage. As of December 1, 2015 the ADS-B ground network is completely deployed across the continental United States, Hawaii, Puerto Rico, and Guam. The ADS-B ground network has been installed in Alaska but does not cover the entire state. Refer to the following website for information on existing ADS-B coverage in the National Airspace System (NAS):
http://www.faa.gov/nextgen/programs/adsb/coverageMap/
4.3.2.2 Distance From Ground Station.
This flight profile does not specify the distance the aircraft must be from an ADS-B ground station. Transmit power is evaluated through ground testing instead of demonstrating a minimum air-to-ground reception distance.
4.3.2.3 Altitude.
Fly the aircraft at multiple altitudes throughout the flight within ADS-B coverage. There is no maximum or minimum altitude required for the flight test.
4.3.2.4 Turns.
Verify the ADS-B system performs properly during turning maneuvers.
During the flight, place the aircraft in various normal configurations such as takeoff, approach, landing, and cruise configuration if appropriate for the airframe. During the flight, perform at least two left and two right 360-degree turns. Table 5 below provides the suggested altitude, speed, and bank angle at which these turns should be made. The intent of this test is to ensure the ADS-B system operates properly over the normal flight regimes of the aircraft under test. Variations on altitude, speed, and bank angle are acceptable as long as the intent of the test is met.
44 Table 5. Turns Part 23 Aircraft Configuration Altitude Range (in feet AGL) Speed Range Bank Angle Takeoff 3000-5000 1.4 VS 30° Approach or Landing 2000-7000 1.4 VS 30° Cruise 7000-10000 1.5 VS to 1.8 VS 30° Part 25 Aircraft Configuration Altitude Range Speed Range Bank Angle Takeoff 3000-5000 V2 + 20 kts 30° Approach or Landing 2000-7000 VAPP + 20 kts 30° Cruise 7000-10000 1.5 VS to 1.8 VS 30° Part 27 Rotorcraft Configuration Altitude Range Speed Range Bank Angle Landing 1000-3000 VY + 10 kts 30° Cruise 2000-5000 0.8 VNE or 0.8 VH 30° Part 29 Rotorcraft Configuration Altitude Range Speed Range Bank Angle Landing 1000-3000 VY + 10 kts 30° Cruise 2000-10000 0.8 VNE or 0.8 VH 30°
4.3.2.5 Climbs/Descents.
Verify the ADS-B system performs properly during climbs and descents.
Table 6 provides a suggested airspeed at which climbs should be made during the test flight. Table 7 provides a suggested airspeed at which descents should be made during the test flight. Climbs and descents should be at least one minute in length. The intent of this test is to ensure the ADS-B system operates properly over the flight regime of the aircraft under test. Variations on climb and descent rates are acceptable as long as the intent of the test is met.
45 Table 6. Climb Speeds Configuration Part 23 Aircraft Part 25 Aircraft Part 27 Rotorcraft Part 29 Rotorcraft Take off VY VFE - 10 kts VY VY Cruise VH VMO - 10 kts 0.8 VNE or 0.8 VH 0.8 VNE or 0.8 VH Table 7. Descent Speeds Configuration Part 23 Aircraft Part 25 Aircraft Part 27 Rotorcraft Part 29 Rotorcraft Cruise VNE - 10 VMO - 10 kts 0.8 VNE or 0.8 VH 0.8 VNE or 0.8 VH Approach VFE - 10 VFE - 10 kts VY + 10 kts VY + 10 kts Landing VFE - 10 VFE - 10 kts N/A N/A
4.3.2.6 Position Accuracy.
Using a known waypoint, fly a north/south course that crosses the defined waypoint followed by an east/west course that crosses the same defined waypoint.
4.3.3 Post-Flight Data Analysis.
You must accomplish a post-flight data analysis to ensure the aircraft is transmitting accurate ADS-B information. Ensure all data associated with the track is consistent, such as position, 24-bit address, velocity, flight ID, barometric altitude, Mode 3/A code, emitter category, and geometric altitude. The post-flight data analysis should also reveal if there were any unexpected data dropouts that might be caused by intermittent wiring interfaces or interface incompatibility. The flight test does not require the use of a truth source to accomplish post-flight data analysis; however, the FAA will provide radar data when available to help analyze the flight track. At a minimum, analyze the following areas:
4.3.3.1 Rule Compliance.
Review the data from the FAA ground system for the flight to ensure the installed system meets its stated accuracy and integrity performance under flight conditions. We recommend that you accomplish a GNSS performance prediction for the applicable time of your test and ensure the ADS-B system meets the predicted performance. Due to the design of existing GNSS receivers and typical GPS constellation configurations, there will be time periods when unaugmented GNSS solutions drop below the NIC and NACP performance required by the rule. Such outages usually do not occur for more than 20 minutes, and many are of much shorter durations. If the integrity and accuracy of an existing GNSS installation does not meet the rule requirements during the test flight, the
46 applicant should show that poor performance was caused by the constellation during the period of time that the flight occurred. If that cannot be established as the cause of the poor performance, there may be a problem with the position sensor installation that needs to be investigated and resolved. Resolution of this type of issue will probably require the involvement of the position source manufacturer. There may also be short periods where position messages transmit NIC = 0, velocity messages transmit NACV = 0, and status messages transmit NACP = 0, SIL = 0.
These can be caused by antenna shadowing and switching effects, and do not indicate an installation problem if they are infrequent and of short duration. All such outages must be less than 5 seconds in duration to avoid operational impacts. This condition may not occur more often than once every 1000 position transmissions when averaging all outages over the flight duration. If this condition occurs more often during the flight test, the applicant must establish root cause and provide a solution before granting installation approval. Demonstrate that you meet all § 91.227(c)(1) accuracy and integrity requirements, listed in Table 8, during flight.
Table 8. Accuracy and Integrity Requirements During Flight Ensure NIC ≥ 7 throughout the flight. Rc <370.4 m (0.2 nm) Ensure NACP ≥ 8 throughout the flight. EPU <92.6 m (0.05 nm) Ensure NACV ≥ 1 throughout the flight. < 10 m/s Ensure SIL = 3 throughout the flight ≤1x10-7 Ensure SDA ≥ 2 throughout the flight ≤1x10-5
4.3.3.2 Position Accuracy/Integrity.
Compare the track received by the FAA ground system with the actual flight track. There is no specific tolerance for this test; rather, the applicant must show there are no gross position errors, track offsets or discontinuities, or other obvious anomalies.
4.3.3.3 Velocity Accuracy.
Compare the velocity received by the FAA ADS-B ground system with the actual velocities flown. There is no specific tolerance for this test;
rather, you must show that they compare reasonably, and that there are no gross velocity errors.
4.3.3.4 Geometric Altitude Accuracy.
Compare the geometric altitude received by the FAA ground system with the geometric altitude flown. There is no specific tolerance for this test;
47 rather, you must show that they compare reasonably, and that there are no gross geometric altitude errors.
4.3.3.5 Barometric Pressure Altitude Accuracy.
Compare the barometric pressure altitude received by the FAA ground system with the actual barometric pressure altitude flown. There is no specific tolerance for this test; rather, you must show that they compare reasonably, and that there are no gross barometric pressure altitude errors.
4.3.3.6 Validity Checks.
The FAA plans to use radar, multilateration, and UAT passive ranging as independent validity checks for ADS-B. The validity check will indicate “valid” when the independent check is able to validate the ADS-B position, “invalid” when it determines the ADS-B position is out of tolerance, and “unknown” if it is unable to accomplish the validity check.
If a validity or enhanced validity status is provided in the flight test data, you must show that it never indicates “invalid”.
Note: Validity checks are planned to ensure the ADS-B position is within
0.56 nm in terminal airspace and 1.9 nm in en-route airspace. Enhanced validity checks are planned to ensure the ADS-B position is within 0.2 nm within approximately 15 nm of terminal radars and close proximity to airports with Airport Surface Detection Equipment, Model X (ASDE-X) systems.
4.4 International Flight Test Options.
If the aircraft is being flight tested outside of the United States, it is acceptable to perform the flight test against another Air Navigation Service Provider’s (ANSP) ground system. Other ANSP’s ground systems must be fully operational and appropriately qualified to provide ATC separation services. Other ANSP ground systems must also be able to provide all parameters required by § 91.227. You will have to work with the foreign ANSP to retrieve the necessary data.
4.5 Subsequent Flight Test Data Reuse.
The flight test guidelines in section 4.3 of this AC apply to initial TC/STC applications.
Flight test data from a similar installation, covered under a previous TC/STC, may be used instead of a new flight test if the following conditions can be confirmed through the documentation of the previous STC:
4.5.1 Position Source Equipment.
The position source must be identical to that of the other Amended Type Certificate (ATC), TC, or STC documentation. Equipment families that use the same baseline design may make a case for equivalence.
4.5.2 ADS-B Equipment.
The ADS-B equipment must be identical to that of the other ATC/TC/STC documentation. Equipment families that use the same baseline design may make a case for equivalence.
4.5.3 System Interface.
A direct interface must be used between the position source and the ADS-B equipment, and that interface must be identical to that of the previous ATC/TC/STC. Aircraft with data concentrators will have to re-accomplish the flight test, even if the equipment is identical.
4.5.4 Air-Data Interface.
The air-data interface to the ADS-B equipment must be identical to that of the previous ATC/TC/STC. The actual air-data source may be different equipment; only the interface to the ADS-B equipment needs to be identical. However, if the air-data source is different, more extensive ground testing should be accomplished, to include a dynamic test where the air-data source has simulated inputs from sea level to the maximum certified operating altitude of the aircraft. Care should be taken to ensure broadcast of simulated altitude information does not cause interference with ATC or ADS-B IN applications.
4.5.5 Heading Interface.
The heading interface to the ADS-B equipment (if applicable) must be identical to that of the previous ATC/TC/STC. The heading source may be different; only the interface to the ADS-B equipment needs to be identical. If the heading source is different, testing should be accomplished, to include positioning the aircraft at multiple headings on the surface to verify heading accuracy.
4.5.6 TCAS Interface.
The TCAS interface to the ADS-B equipment must be identical to that of the previous ATC/TC/STC. The TCAS equipment may be different; only the interface to the ADS-B equipment needs to be identical.
Appendix A A-1 APPENDIX A. MESSAGE ELEMENT DESCRIPTIONS A.1 Purpose.
This appendix provides a description of the message elements that may be contained in an ADS-B OUT message.
A.2 Message Elements.
A.2.1 ADS-B IN Capability.
Two messages indicate the ADS-B IN status of the aircraft. The 1090 ADS-B IN message indicates if the aircraft has the ability to receive 1090ES ADS-B messages installed. The UAT ADS-B IN message indicates if the aircraft has the ability to receive UAT ADS-B messages installed. An indication of ADS-B IN capability is important because TIS-B and ADS-R services are provided specific to an aircraft’s position relative to other aircraft. The FAA may only provide complete TIS-B and ADS-R services to aircraft that indicate they are ADS-B IN capable. ADS-B IN capability is required to be transmitted by § 91.227.
A.2.2 Airspeed.
Optionally, true airspeed or indicated airspeed may be transmitted. The airspeed source should be approved to output airspeed data. An air data computer meeting the minimum performance requirements of TSO-C106 is one acceptable source. Do not interface an airspeed source to the ADS-B that has not been approved for cockpit display.
A.2.3 Barometric Pressure Altitude.
This parameter indicates the aircraft’s barometric pressure altitude referenced to standard sea level pressure of 29.92 inches of mercury or 1013.2 hectopascals. The barometric pressure altitude is required to be transmitted by § 91.227.
A.2.4 Call Sign/Flight ID.
The term “aircraft call sign” is the radiotelephony call sign assigned to an aircraft for voice communications purposes. (This term is sometimes used interchangeably with “flight identification” or “flight ID”). For general aviation aircraft, the aircraft call sign is normally the national registration number; for airline and commuter aircraft, the call sign is usually comprised of the company identification and flight number (and therefore not linked to a particular airframe) and, for the military, it usually consists of numbers and code words with special significance for the operation conducted. The call sign or aircraft registration number is required to be transmitted by § 91.227 except when using the TSO-C154c anonymity feature.
A.2.5 Emergency Status.
This parameter alerts ATC that the aircraft is experiencing emergency conditions and indicates the type of emergency. Applicable emergency codes are found in ICAO
Appendix A A-2 Annex 10 Volume 4, Surveillance Radar and Collision Avoidance Systems. This information alerts ATC to potential danger to the aircraft so it can take appropriate action. Emergency status is required to be transmitted by § 91.227.
A.2.6 Emitter Category.
The emitter category provides an indication of the aircraft’s size and performance capabilities. Emitter categories are defined in TSO-C166b and TSO-C154c. Emitter category is designed primarily to provide information on the wake turbulence that an aircraft produces. Emitter category is required to be transmitted by § 91.227.
A.2.7 Geometric Altitude.
The geometric altitude is a measure of altitude provided by a satellite-based position service and is not affected by atmospheric pressure. Geometric altitude is only available with a GNSS position source. Geometric altitude for ADS-B purposes is the height above the World Geodetic System 1984 (WGS-84) ellipsoid (HAE). Geometric altitude is required to be transmitted by § 91.227.
A.2.8 Geometric Vertical Accuracy (GVA).
The GVA indicates the 95-percent accuracy of the reported vertical position (geometric altitude) within an associated allowance.
A.2.9 GNSS Antenna Offset and Position Offset Applied (POA).
A.2.9.1 The GNSS antenna offset indicates the longitudinal distance between the most forward part of the aircraft and the GNSS antenna, and the lateral distance between the longitudinal center line of the aircraft and the GNSS antenna. Also, refer to section 3.8.4.1 – 3.8.4.3 and Figure 3 of this AC.
A.2.9.2 The POA setting of the GNSS antenna offset indicates that the broadcast position is referenced to the aircraft’s ADS-B position reference point versus the GNSS antenna location. Also, refer to section 3.8.4.1 -
3.8.4.3and Figure 3 of this AC. For further details about POA, refer to RTCA/DO-338, section 3.2.4.1.
A.2.10 Ground Speed.
This parameter is also derived from the position sensor and provides ATC with the aircraft’s speed over the ground. This parameter is reported in the surface position message.
A.2.11 Ground Track Angle.
The ground track angle is the direction of the horizontal velocity vector over the ground. Ground track or heading is required to be transmitted while on the ground to transmit complete velocity information.
Appendix A A-3 A.2.12 Heading.
Heading indicates the direction in which the nose of the aircraft is pointing. There is no heading accuracy metric. Heading or ground track is required to be transmitted while on the ground to transmit complete velocity information.
A.2.13 Horizontal Velocity.
The horizontal velocity provides the rate at which an aircraft changes its horizontal position with a clearly stated direction. Horizontal velocity is provided with the north/south velocity and the east/west velocity parameters while airborne. Horizontal velocity is provided by a combination of the ground speed and heading or ground track while on the surface. TSO-C166b and TSO-C154c require that the north/south velocity, east/west velocity, ground speed, and ground track come from the same source as the position. Heading information may come from a separate source. Horizontal velocity is required to be transmitted by § 91.227.
A.2.14 ICAO 24-bit Address.
The ICAO 24-bit address is a unique address assigned to an aircraft during the registration process. ICAO 24-bit addresses are defined blocks of addresses assigned for participating countries or states worldwide. In the United States, civil aircraft are assigned an address from an encoding scheme based on the aircraft registration number (“N” number). Additional information regarding the 24-bit address can be found in ICAO Annex 10, Part I, Volume III, appendix to Chapter 9, A World-Wide Scheme for the Allocation, Assignment and Application of Aircraft Addresses. The ICAO 24-bit address is required to be transmitted by § 91.227 except when using the TSO-C154c anonymity feature.
A.2.15 IFR Capability.
This parameter existed in TSO-C166a and TSO-C154b compliant equipment, but was removed from TSO-C166b and TSO-C154c equipment.
A.2.16 IDENT.
IDENT is a flag manually set by the pilot at the request of ATC in ATCRBS, Mode S, and ADS-B messages. The pilot manually enables the IDENT state, which highlights their aircraft on the controller’s screen. IDENT is required to be transmitted by § 91.227.
A.2.17 Latitude and Longitude.
These parameters are derived from the position source and provide a geometric based position. Reference all geometric position elements broadcast from the ADS-B unit to the WGS-84 ellipsoid. Latitude and longitude are required to be transmitted by §
91.227.
A.2.18 Length and Width of Aircraft.
This parameter provides ATC and other aircraft with quick reference to the aircraft’s dimensions while on the surface. Aircraft length and width is required to be transmitted by § 91.227.