Appendix A in an environment where these unnecessary advisories are considered likely to occur (based on either airspace design, air traffic communications, visual acquisition or utilization of traffic displays), a reduction in vertical velocity is recommended until reaching the assigned altitude.
As appropriate, the vertical velocity should be reduced to a rate between 500 and 1,500 ft/min, when approaching an altitude between 1,000 and 2,000 ft. above or below the altitude assigned in the ATC instruction or clearance.
After deviating from an ATC clearance or instruction in response to a TCAS II RA, notify ATC of the deviation as soon as possible.
Following a TCAS II “CLEAR OF CONFLICT” advisory, the pilot should expeditiously return to the applicable ATC clearance unless otherwise directed by ATC.
NOTE: The threat aircraft track or altitude information can be lost during an RA. If so, the RA will terminate without a “CLEAR OF CONFLICT” annunciation.
(2) TCAS II Operation:
Pilot-Initiated TCAS II self-test:
(a) The TCAS II should be tested using the pilot-initiated self-test feature during cockpit preparation. A successful test is indicated by (provide test results from particular TCAS II system).
(b) Use of the self-test function in flight will inhibit TCAS II operation for up to (provide time for a particular TCAS II system) seconds.
(c) The ATC transponder will not function during some portion of the self-test sequence.
(d) All aircraft systems providing information to TCAS II must be operating in their normal mode during the Self-Test.
Ground Operation:
(a) When equipped with a TSO-C119c or earlier TCAS II unit,
(1) To preclude unnecessary transponder interrogations and possible interference with ground surveillance systems, do not activate TCAS (TA or TA/RA mode) until taking the active runway for departure. Selection of XPDR is adequate for ATC and nearby Automatic Dependent Surveillance-Broadcast equipped aircraft to “see” the aircraft while taxiing on the airport surface.
(2) After landing and clearing of the runway, de-select from TA or TA/RA mode. Select XPNDR while taxiing to the ramp area. Upon shutdown, select STBY on the transponder.
A-15
Appendix A
(b) When equipped with a TSO-C119d or later TCAS unit,
(1) To preclude unnecessary transponder interrogations and possible interference with ground surveillance systems, do not activate TCAS (TA or TA/RA mode) until taking the active runway for departure. Selection of XPDR is adequate for ATC and nearby Automatic Dependent Surveillance-Broadcast equipped aircraft to “see” the aircraft while taxiing on the airport surface.
NOTE: The TA symbol will not be annunciated for any target while own-ship is on the ground when TA or TA/RA mode is selected.
(2) After landing and clearing of the runway, de-select from TA or TA/RA mode. Select XPNDR while taxiing to the ramp area. Upon shutdown, select STBY on the transponder.
A-16
Appendix A TA Mode:
(a) The TA position should only be used to preclude unnecessary RAs when intentionally operating near other aircraft such as to closely spaced parallel runways (less than 1200 feet apart).
(b) In TA mode, RAs will not be issued.
WX-ONLY Mode:
(a) When WX-ONLY mode is selected, traffic information, traffic advisories, and resolution advisories are inhibited on the weather radarscope. Therefore, this mode should be used only in the event TCAS interferes with weather information. (This example is to show the kind of procedure to be developed. Procedures will vary depending upon installation; such as pop-up display modes, PFD/ND implementation, etc.)
(3) TCAS II System Characteristics:
(a) “CLIMB” RAs are inhibited with flaps greater than XX degrees.
(b) When below 1000 feet AGL, the TCAS II will automatically switch into the TA only mode.
(c) “INCREASE CLIMB” RAs are inhibited with flaps greater than XX degrees.
(d) “DESCEND” RAs are inhibited below 1200 feet AGL while climbing and below 1000 feet AGL while descending.
(e) “INCREASE DESCENT” RAs are inhibited below 1450 feet AGL.
(f) Voice messages are inhibited below 600 feet AGL while climbing and below 400 feet AGL while descending.
(g) The TCAS II surveillance may not function at distances less than 900 feet.
(h) During windshear and/or GPWS/TAWS warnings, TCAS II switches automatically into a TA only mode with aural annunciation inhibited. In this mode, RAs are not issued and current RAs become TAs. The TCAS II remains in TA Only mode for 10 seconds after the windshear or GPWS/TAWS warning is removed. TCAS II aural annunciations are enabled immediately following the removal of the windshear or GPWS/TAWS warning aural annunciation.
A-17
Appendix A
(4) TCAS II Abnormal Procedures:
NOTE: These examples are to show the kinds of abnormal procedures to be developed. Procedures will vary depending upon the installation, such as dual Mode S, and so forth.
RA OFF Flag in IVSI
(a) Verify TCAS II/transponder function selector is in TA/RA position.
(b) If TA/RA is selected and “RA OFF” flag is in view, then the pilot with the operable IVSI (flag not in view) should be the pilot flying.
AMBER FLAG in IVSI
(a) Check XPDR FAIL light.
(b) If OFF, select other altitude source.
(c) If ON, select alternate ATCRBS transponder. (TCAS II will no longer be available).
XPDR FAIL Light Illuminated
(a) Select alternate ATCRBS transponder. (TCAS II will no longer be available.)
Hybrid Surveillance Failure Annunciation
(a) For installations that are capable of annunciating hybrid surveillance failures to the pilot:
(1) Make a logbook entry to record the failure. No other crew action is
required. TCAS continues to provide traffic annunciation and collision avoidance
protection even when hybrid surveillance has failed.
SECTION IV – PERFORMANCE.
(a) No change from basic airplane flight manual.
A-18
Appendix B Appendix B. Transponder Ground Tests & Evaluations.
1. Tests and Evaluations. Using a suitable calibrated transponder test set, conduct the following tests:
NOTE: CAUTION! When conducting any ground testing of the transponder or TCAS system, you must prevent being a source of interference to ATC or other TCAS aircraft operating in the area.
Ground maintenance checks or ramp testing (such as altimetry or bearing accuracy testing) can cause data to be transmitted which produce false targets for the ground ATC surveillance systems or airborne TCAS aircraft. These false indications of “intruder aircraft” could result in unnecessary ATC communications and possibly in TCAS induced aircraft maneuvers. Therefore, conduct such testing in coordination with ATC and use antenna shielding (that is, transmission absorption covers or caps) to prevent test data that could generate false intruder information from being transmitted. Using high-powered, hangar-mounted transponders to conduct ramp testing is NOT an acceptable means for conducting either TCAS or transponder ramp testing.
a. Mode Test. Identifies modes of operation. Interrogations are made in Modes A, C, and S (uplink format 11) to determine which modes the transponder replies to. These are the modes tested during the Auto Test sequence.
b. Reply Delay. Interrogates with valid modes and verifies Reply delay minus Range delay (average of best 8 out of 13 replies) equals:
(1) 128.00 µs (±0.25 µs) for Mode S.
(2) 3.00 µs (±0.50 µs) for ATCRBS.
c. Reply Jitter. Interrogates with valid modes and verifies, using best 8 out of 13 replies. Reply Jitter (changes In Reply Delay) is less than or equal to:
(1) 0.05 µs for Mode S.
(2) 0.06 µs for Intermode (All-Call).
(3). 0.10 µs for ATCRBS.
B-1
Appendix B
d. ATCRBS Reply. Interrogates with ATCRBS (Modes A and C) interrogations and verifies:
(1) F1 to F2 spacing is 20.3 µs (±0.10 µs).
(2) F1 and F2 pulse width between the 0.5 amplitude point on the leading and trailing edge is 0.45 µs (±0.10 µs).
e. SLS Level. Interrogates with valid ATCRBS Interrogations including P2 pulse.
Interrogations are conducted with P2 level at -9 dB and then again at 0 dB. Test verifies:
(1) Transponder does not reply when P2 level is at 0 dB (UUT is suppressed).
(2) Transponder replies when P2 level is at -9 dB (UUT is not suppressed).
f. ATCRBS-Only All-Call. Interrogates with an ATCRBS-only All-Call and verifies:
(1) If Mode S is valid, no reply is received from a Mode S transponder.
(2) If no Mode S, reply is received from an ATCRBS transponder.
g. Mode S All-Call. Interrogates with the ATCRBS (mode A) Mode S All- Call.
Address received in downlink format (DF) 11 is then used in an uplink format (UF) 4 interrogation to solicit a DF4 reply. The address received is decoded and compared with the address sent.
h. Invalid ICAO 24-bit aircraft address. Interrogates with Mode S interrogations using two addresses different from the address determined by the Mode S All-Call, UF11. Test verifies no reply is received. Addresses used are one greater and 256 greater than the correct address.
i. SPR On/Off. Interrogates with a Mode S interrogation with the Synchronous Phase Reversal (SPR) on, verifying correct reply is received. Then same interrogation is sent again with the SPR off, verifying no reply is received.
j. Mode S UF0. Interrogates with Mode S uplink format 0 (Short air- to-air surveillance, ACAS) verifying reply is received that has correct altitude (compared with Mode C altitude), address (compared with Mode Test address) and format.
k. Mode S UF4. Interrogates with Mode S uplink format 4 (Surveillance, altitude request), verifying reply is received that has correct altitude (compared with Mode C altitude), address (compared with Mode Test address) and format.
l. Mode S UF5. Interrogates with Mode S uplink format 5 (Surveillance, identity request) verifying reply is received that has correct identity (compared with Mode A identity), address (compared with Mode Test address) and format.
B-2
Appendix B
m. Mode S UF11. Interrogates with Mode S uplink format 11, verifying reply is received that has correct address (compared with Mode Test address) and format.
n. Mode S UF16. Interrogates with Mode S uplink format 16 (Long air- to-air surveillance, ACAS), verifying reply, if received, has correct altitude (compared with the Mode C altitude), address (compared with Mode Test address) and format. No reply to UF16 does not fail Mode S in Auto Test.
o. Mode S UF20. Interrogates with Mode S uplink format 20 (Comm A, altitude request) verifying reply received has correct altitude (compared with Mode C altitude), address (compared with Mode Test address) and format. No reply to UF20 does not fail Mode S in Auto Test.
p. Mode S UF21. Interrogates with Mode S uplink format 21 (Comm A, identity request) verifying reply received has correct identity (compared with Mode A identity), address (compared with Mode Test address) and format. No reply to UF21 does not fail Mode S in Auto Test.
q. Acquisition Squitter. Verifies squitters are being received from the UUT every 0.8 to
1.2 seconds.
r. Frequency. Verifies frequency of transponder is 1090 MHz (± frequency tolerance as specified by equipment manufacturer). Frequency is displayed in the Auto Test screen.
s. Diversity. Verifies diversity isolation (power level difference between UUT “On” antenna squitters and “Off” antenna squitters) is greater than or equal to 20 dB. Diversity isolation is displayed in Auto Test screen.
NOTE: To ensure >=20 dB dynamic range, test must be run within 50 feet (15.24 meters) of UUT antenna being tested.
t. MTL Difference. Verifies Receiver Sensitivity (MTL) to Mode A interrogations equals MTL to Mode C interrogations (±1.0 dB).
u. Altitude Reporting. Verifies the reported altitude in the AC field of DF0, DF4, D16, and D20 corresponds to the value provided from the on-board altitude source to the transponder and is reported with the quantization indicated by the Q bit in the AC field. For aircraft with 25 foot or better pressure altitude sources, pressure altitude information should be reported in 25 foot increments. Pressure altitude data obtained from a source with larger than 25-foot resolution must not be reported using 25-foot increments.
NOTE: To ensure the correct reporting of altitude with the proper quantization, the aircraft altitude must be incremented over a 300-foot range in 25 foot increments.
B-3
Appendix C Appendix C. Background.
1. Early TCAS. The airline industry has been working with the Air Transport Association of America (ATA) since 1955 toward a collision avoidance system. It was not until the mid 1970s, however, that research centered on using signals from ATCRBS airborne transponders as the cooperative element of a collision avoidance system. This technical approach allows a collision avoidance capability on the flight deck, which is independent of the ground system. In 1981, the FAA announced our decision to implement an aircraft collision avoidance concept called the Traffic Alert and Collision Avoidance System (TCAS). The concept is based upon agency and industry development efforts in the areas of beacon based collision avoidance systems and air-to-air discrete address communications techniques utilizing Mode S airborne transponder message formats.
a. A short time later, prototypes of TCAS II were installed on two Piedmont Airlines Boeing 727 aircraft, and were flown on regularly scheduled flights. Although the displays were located outside the view of the flight crew and seen only by trained observers, these tests did provide valuable information on the frequency and circumstances of alerts and their potential for interaction with the ATC system. On a follow-on phase II program, a later version of TCAS II was installed on a single Piedmont Airlines Boeing 727, and the system was certified in April 1986, then subsequently approved for operational evaluation in early 1987. Since the equipment was not developed to full standards, the system was only operated in visual meteorological conditions. Although the flight crew operated the system, the evaluation was primarily for the purpose of data collection and its correlation with flight crew and observer observation and response.
b. Later versions of TCAS II manufactured by Bendix/King Air Transport Avionics Division were installed and approved on United Airlines airplanes in early 1988. Similar units manufactured by Honeywell were installed and approved on Northwest Airlines airplanes in late 1988. This limited installation program operated TCAS II units approved for operation as a fulltime system in both visual and instrument meteorological conditions on three different aircraft types. The operational evaluation programs continued through 1988 to validate the operational suitability of the systems.
2. Recent TCAS Developments.
a. Since the early 1990s, an operational evaluation known as the TCAS Transition Program (TTP) collected and analyzed data on the performance and use of TCAS II in both the U.S.
National Airspace System (NAS) and in other airspace worldwide. As a result of these analyses, changes to TCAS II were developed, tested, and implemented in the early to mid 1990s. These changes, collectively known as TCAS II V7.0, were implemented by industry in the late 1990s.
TCAS II V7.0 complies with the International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARP) for ACAS II. TCAS II V7.0 is mandated for carriage in Australia, India and certain European countries and was mandated for carriage in 2003 by ICAO.
In addition, if you operate an aircraft that is equipped with TCAS II in RVSM airspace, it must be a TCAS II that meets TSO-C119b (V7.0) or a later version.
C-1
Appendix C
b. Investigation of operational problems resulted in changes to TCAS II V7.0. The changes resulting from that investigation resulted in TCAS II V7.1.
c. While developing corrective action for the operational problems, the Federal Aviation Administration (FAA), along with industry representatives, decided to develop performance standards for TCAS II Hybrid Surveillance. That work resulted in creation of RTCA/DO-300, Minimum Operational Performance Standards (MOPS) for Traffic Alert and Collision Avoidance System II (TCAS II) Hybrid Surveillance.
C-2
Appendix D Appendix D. Related Documents.
1. 14 CFR Parts. You can apply current portions of 14 CFR for the design, substantiation, certification and operational approval of TCAS II and Mode S transponders. Sections prescribing requirements for these types of systems are listed below. Order copies of 14 CFR Parts 21, 23, 25, 27, 29, 43, 91, 121, and 135 from the Superintendent of Documents, Government Printing Office, Washington, D.C. 20402-9325, telephone (202) 512-1800, fax
(202) 512-2250. You can also get copies from the Government Printing Office (GPO), electronic CFR Internet website at http://www.gpoaccess.gov/cfr/.
a. 14 CFR § 25.301 Loads.
b. 14 CFR § 25.303 Factor of safety.
c. 14 CFR § 25.305 Strength and deformation.
d. 14 CFR § 25.561 General.
e. 14 CFR § 25.603 Materials.
f. 14 CFR § 25.609 Protection of structure.
g. 14 CFR § 25.629 Aeroelastic stability requirements.
h. 14 CFR § 25.869 Fire protection systems.
i. 14 CFR § 25.1301 Function and installation.
j. 14 CFR § 25.1302 Installed systems and equipment for use by the flightcrew.
k. 14 CFR § 25.1303 Flight and navigation instruments.
l. 14 CFR § 25.1307 Miscellaneous equipment.
m. 14 CFR § 25.1309 Equipment, systems, and installations.
n. 14 CFR § 25.1316 System Lightning Protection.
o. 14 CFR § 25.1317 High-intensity Radiated Field (HIRF) Protection.
p. 14 CFR § 25.1321 Arrangement and visibility.
q. 14 CFR § 25.1322 Warning, caution, and advisory lights.
r. 14 CFR § 25.1331 Instruments using a power supply.
s. 14 CFR § 25.1333 Instrument systems.
t. 14 CFR § 25.1335 Flight director systems.
u. 14 CFR § 25.1351 Electrical Systems and Equipment: General.
v. 14 CFR § 25.1353 Electrical equipment and installations.
w. 14 CFR § 25.1355 Distribution system.
x. 14 CFR § 25.1357 Circuit protective devices.
D-1
Appendix D
y. 14 CFR § 25.1381 Instrument lights.
z. 14 CFR § 25.1431 Electronic equipment.
aa. 14 CFR § 25.1541 Markings and Placards: General.
bb. 14 CFR § 25.1581 Airplane Flight Manual: General.
cc. 14 CFR § 25.1585 Operating procedures.
NOTE: References to 14 CFR part 25 are appropriate when installing TCAS II on transport category airplanes. When TCAS II is to be certified for non-transport category airplanes, use the equivalents to the above 14 CFR part 25 sections in other parts of the regulations.
2. FAA ACs. You will find a current list of ACs on the FAA Internet website http://www.faa.gov/regulations_policies/advisory_circulars/.
a. AC 20-131A, Airworthiness Approval of Traffic Alert and Collision Avoidance Systems (TCAS II) and associated Mode S Transponders.
b. AC 20-115, Radio Technical Commission on Aeronautics (RTCA) Document DO 178B.
c. AC 25.1309-1A, System Design and Analysis.
d. AC 25-11A, Electronic Flight Deck Displays.
e. AC 120-55C, Air Carrier Operational Approval and Use of TCAS II.
3. FAA TSOs. You will find a current list of TSOs on the FAA Internet website Regulatory and Guidance Library at http://rgl.faa.gov. You will also find the TSO Index of Articles at the same site.
a. TSO-C112d, Air Traffic Control Radar Beacon System/Mode Select (ATCRBS/Mode S) Airborne Equipment.
b. TSO-C119d, Traffic Alert and Collision Avoidance System (TCAS) Airborne Equipment, TCAS II With Hybrid Surveillance Functionality.
4. FAA Other. You will find this related information on the FAA Internet website Regulatory and Guidance Library at http://rgl.faa.gov. The document is posted adjacent to the links for AC 20-151 and TSO-C119.
a. Introduction to TCAS II V7.1, Feb 28, 2011 D-2