Appendix 4 APPENDIX 4. PHRASEOLOGY FOR TCAS EVENTS
1. RADIO COMMUNICATION. In order to keep everyone informed during a TCAS maneuver, radio communication should be in terminology common to all parties on the frequency regarding a TCAS Resolution Advisory (RA). All transmissions should contain:
• Name of the air traffic control (ATC) facility,
• Aircraft identification (ID), and
• Nature of the TCAS deviation.
2. TCAS RAs. When a flightcrew receives a TCAS RA to either climb or descend from their assigned altitude, or the RA otherwise affects their ATC clearance, the crew should inform ATC when beginning the excursion from clearance or as soon as workload allows in the following manner: “XYZ Center, (Aircraft ID), TCAS RA,” (e.g., “New York Center, Quantum 321, TCAS RA.”)
3. SEPARATION. Following such a communication, the designated air traffic facility is not required to provide approved standard separation to the TCAS maneuvering aircraft until the TCAS encounter is cleared and standard ATC separation is achieved. If workload permits, traffic information should be provided in accordance with the current edition of Federal Aviation Administration (FAA) Order JO 7110.65, Air Traffic Control. When the RA is clear, the flightcrew should advise ATC that they are returning to their previously assigned clearance or subsequent amended clearance in the following manner: “ABC Center, (Aircraft ID), clear of conflict, returning to assigned altitude,” (e.g., “Boston Center, Northern 429, clear of conflict, returning to assigned altitude.”)
4. RENEGOTIATED CLEARANCES. When the deviating aircraft has renegotiated its clearance with ATC, the designated air traffic facility should resume providing appropriate separation services in accordance with Order JO 7110.65.
NOTE: No communication is required if the pilot is able to satisfy the RA guidance and maintain the appropriate ATC clearance.
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Appendix 5 APPENDIX 5. TCAS II GROUND AND FLIGHT TRAINING REQUIREMENTS
1. INTRODUCTION. This appendix provides a set of training standards for TCAS II pilot training. The information contained in this appendix related to traffic advisories (TA) is also applicable to TCAS I users. Training standards are divided into areas of instruction required for ground training (academics) and the performance objectives for the maneuvers required in flight training.
2. TCAS GROUND TRAINING. Ground training must cover the following areas:
a. General Concepts of TCAS Operation. TCAS ground training should cover, in general terms, TCAS theory to the extent appropriate to ensure proper operational use. Aircrews should understand basic concepts of TCAS logic, closest point of approach (CPA), tau, and altitude separation thresholds for the issuance of Resolution Advisories (RA), as well as the relationship between displayed traffic information and issuance of TAs and RAs. The ground training program should address the following:
(1) The meaning of TAs and preventive versus corrective RAs;
(2) Increase, reversal, crossing, and weakened RAs;
(3) That TCAS II assures separation from aircraft equipped with an altitude-reporting transponder;
(4) The detection and protection provided by TCAS against altitude-reporting and non-altitude-reporting intruders;
(5) That the system detects multiple aircraft;
(6) TCAS-to-TCAS coordination;
(7) The potential impact of not following RAs;
(8) TCAS surveillance range versus display range;
(9) When an intruder will not be displayed;
(10) TCAS on-ground performance; and
(11) The continued applicability of the see-and-avoid concept.
b. Expected Flightcrew Response and Level of Protection Provided by TCAS.
Academic training should explain the normal, expected pilot response to TAs, RAs, use of displayed traffic information to establish visual contact, and constraints on maneuvering based solely on TAs.
c. TCAS General Limitation. There are several system, operational, and/or performance limitations which should be understood that apply to all aircraft types. System limitations include the inability of TCAS to detect nontransponder-equipped aircraft, no RAs issued for traffic Page 1
Appendix 5 without an altitude-reporting transponder, etc. Operational limitations include some RA inhibit altitudes, certain RAs being inhibited by aircraft performance constraints, the inability to comply with an RA due to aircraft performance limitations after an engine failure, and appropriate response to RAs in limiting performance conditions, such as during heavy weight takeoff or while en route at maximum altitude for a particular weight.
d. Air Traffic Control (ATC) Communication and Coordination. Training should discuss communication and coordination with ATC related to or following a TCAS event, when to contact ATC, and accepted TCAS phraseology.
e. TCAS Equipment Components Controls, Displays, Audio Alerts, and Annunciations. Academic training should include a discussion of TCAS terminology, symbology, operation, and optional controls and display features, including any items particular to an air carrier’s implementation or unique to its system.
f. Interfaces and Compatibility with Other Aircraft Systems. Training should discuss the role of the Mode S transponder with a correct, discreet address installed, radar altimeter inputs to TCAS, and weather radar/electronic flight information system (EFIS) interfaces, including any items particular to an air carrier’s implementation or unique to its system.
g. Aircraft Flight Manual (AFM) Information. AFM provisions should be addressed, including information on TCAS modes of operation; normal and atypical flightcrew operating procedures; and response to TAs, RAs, and any AFM limitations.
h. Minimum Equipment List (MEL) Operating Provisions.
i. Pilot Response. Appropriate pilot response to TCAS RAs and TAs, ATC clearance compliance, nuisance alerts, and other such issues.
j. TCAS Event Reporting. The air carrier’s TCAS event reporting policies for flightcrews.
k. Reporting TCAS Malfunctions. Flightcrew procedures for reporting TCAS malfunctions or irregularities, if not otherwise addressed by routine maintenance procedures of that operator.
3. Classroom Training. An understanding of TCAS operation and the criteria used for issuing TAs and RAs may be assessed using the following objectives and criteria. This training should address the following topics:
a. System Operation.
(1) Objective. Demonstrate knowledge of how TCAS functions.
(2) Criteria. The pilot must demonstrate an understanding of the following functions:
Appendix 5
(a) Surveillance:
• TCAS interrogates other transponder-equipped aircraft within a nominal range of 14 nautical miles (NM).
• TCAS surveillance range can be reduced in geographic areas with a large number of ground interrogators and/or TCAS II equipped aircraft.
(b) Collision Avoidance:
• TAs can be issued against any transponder-equipped aircraft which responds to the ICAO Mode C interrogations, even if the aircraft does not have altitude reporting capability.
• RAs can be issued only against aircraft that are reporting altitude and only in the vertical plane.
• RAs issued against a TCAS-equipped intruder are coordinated to ensure the issuance of complementary RAs.
b. Advisory Thresholds.
(1) Objective. Demonstrate knowledge of the criteria for issuing TAs and RAs.
(2) Criteria. The pilot must be able to demonstrate an understanding of the methodology used by TCAS to issue TAs and RAs and the general criteria for the issuance of these advisories to include:
(a) TCAS advisories are based on time to CPA rather than distance. The time must be short and vertical separation must be small, or projected to be small, before an advisory can be issued. The separation standards provided by Air Traffic Services (ATS) are different from the missed distances against which TCAS issues an alert.
(b) Thresholds for issuing a TA or RA vary with altitude. The thresholds are larger at higher altitudes.
(c) The TA tau threshold (trigger point) varies from 20 to 48 seconds before the projected CPA and the RA tau threshold varies from 15 to 35 seconds.
(d) RAs are chosen to provide the desired vertical missed distance at CPA. As a result, RAs can instruct a climb or descent through the intruder aircraft’s altitude.
c. TCAS Limitations.
(1) Objective. To verify the pilot is aware of the limitations of TCAS.
(2) Criteria. The pilot must demonstrate a knowledge and understanding of the TCAS limitations including:
(a) TCAS will neither track nor display non-transponder-equipped aircraft, nor aircraft not responding to TCAS Mode C interrogations.
Appendix 5
(b) TCAS will automatically fail if the input from the aircraft’s barometric altimeter, radio altimeter, or transponder is lost.
NOTE: In some installations, the loss of information from other onboard systems such as an inertial reference system (IRS) or Attitude Heading Reference System (AHRS) may result in a TCAS failure. Individual operators should ensure their pilots are aware of what types of failures will result in a TCAS failure.
(c) An intruder aircraft within 380 feet AGL (nominal value) may or may not be displayed by your TCAS (i.e., declared to be airborne or on the ground, respectively) depending upon whether the intruder is Mode S or ATCRBS Mode C equipped and whether your TCAS-equipped aircraft is airborne or on the ground.
(d) TCAS may not display all proximate transponder-equipped aircraft in areas of high-density traffic.
(e) Because of design limitations, the bearing displayed by TCAS is not sufficiently accurate to support the initiation of horizontal maneuvers based solely on the traffic display.
(f) Because of design limitations, TCAS will not track intruders with a Vertical Speed (VS) in excess of 10,000 feet per minute (fpm). In addition, the design implementation may result in some short-term errors in the tracked VS of an intruder during periods of high vertical acceleration by the intruder.
(g) Ground proximity warning system (GPWS) warnings and windshear warnings take precedence over TCAS advisories. When either a GPWS or windshear warning is active, TCAS aural annunciations will be inhibited.
d. TCAS Inhibits.
(1) Objective. To verify the pilot is aware of the conditions under which certain functions of TCAS are inhibited.
(2) Criteria. The pilot must demonstrate knowledge and understanding of the various TCAS inhibits including:
(a) “INCREASE DESCENT” RAs are inhibited below 1,450 (±100) feet AGL.
(b) “DESCEND” RAs are inhibited below 1,100 (±100) feet AGL.
(c) All RAs are inhibited below 1,000 (±100) feet AGL.
(d) All TCAS aural annunciations are inhibited below 500 (±100) feet AGL. This includes the aural annunciation for TAs.
(e) Altitude and configuration under which climb and increase climb RAs are inhibited. Know if your aircraft type issues climb and increase climb RAs when operating at the Page 4
Appendix 5 aircraft’s certified ceiling. If your aircraft type provides RA climb and increase climb commands at certified ceiling, the commands are to be followed.
NOTE: In some aircraft types, climb or increase climb RAs are never inhibited.
e. Use of Controls.
(1) Objective. To verify the pilot can properly operate all TCAS and display controls.
(2) Criteria. Demonstrate the proper use of controls including:
(a) Aircraft configuration required to initiate a self-test.
(b) Steps required to initiate a self-test.
(c) Recognizing when the self-test was successful and when it was unsuccessful.
When the self-test is unsuccessful, recognizing the reason for the failure, and if possible, correcting the problem.
(d) Low display ranges are used in the terminal area and the higher display ranges are used in the en route environment and in the transition between the terminal and en route environment.
(e) If available, recommended usage of the “ABOVE/BELOW” mode selector.
“ABOVE” mode should be used during climb and the “BELOW” mode should be used during descent.
(f) Recognition that the configuration of the display does not affect the TCAS surveillance volume.
(g) Selection of lower ranges when an advisory is issued to increase display resolution.
(h) If available, selection of the display of absolute altitude instead of relative altitude and the limitations of using this display if a barometric correction is not provided to TCAS.
(i) Proper configuration to display the appropriate TCAS information without eliminating the display of other needed information.
NOTE: The wide variety of display implementations makes it difficult to establish more definitive criteria. When developing the training program, expand these general criteria to cover specific details for an operator’s specific display implementation.
f. Display Interpretation.
(1) Objective. To verify that a pilot understands the meaning of all information that TCAS can display.
Appendix 5
(2) Criteria. The pilot must demonstrate the ability to properly interpret information displayed by TCAS, including:
(a) Other Traffic. Other traffic, for example, is traffic within the selected display range that is not proximate traffic, or causing a TA or RA to be issued.
(b) Proximate Traffic. Proximate traffic, for example, is traffic that is within 6 NM and ±1200 feet.
(c) Non-Altitude Reporting. Non-altitude reporting traffic.
(d) TAs and RAs. No bearing TAs and RAs.
(e) Off-Scale TAs and RAs. Change the selected range for off-scale TAs and RAs to ensure that all available information on the intruder is displayed.
(f) TAs. Select the minimum available display range which allows the display of TAs to provide the maximum display resolution.
(g) RAs (Traffic Display). The minimum available display range of the traffic display which allows the traffic to be displayed should be selected to provide the maximum display resolution.
(h) RAs (RA Display). Pilots should demonstrate knowledge of the meaning of the red and green areas displayed on the RA display and when the green areas will and will not be displayed. Pilots should also demonstrate an understanding of the RA display limitations (for example, if a VS tape is used and the range of the tape is less than 2,500 fpm, an “INCREASE RATE” RA cannot be properly displayed).
(i) Pilot Adjustments. If appropriate, awareness that navigation displays oriented on track-up may require a pilot to make a mental adjustment for drift angle when assessing the bearing of proximate traffic.
NOTE: The wide variety of display implementations will require the tailoring of some criteria. When the training program is developed, these criteria should be expanded to cover details for an operator’s specific display implementation.
g. Use of “TA-ONLY.”
(1) Objective. To verify that a pilot understands the appropriate times to select the “TA-ONLY” mode of operation and the limitations associated with using this mode.
(2) Criteria. The pilot must demonstrate the following:
(a) Knowledge of the operator’s guidance for the use of “TA-ONLY.”
Appendix 5
(b) If “TA-ONLY” is not selected when an airport is conducting simultaneous operations from parallel runways separated by less than 1,200 feet, and to some intersecting runways, RAs can be expected.
(c) The TA aural annunciation is inhibited below 500 feet AGL. As a result, TAs issued below 500 feet AGL may not be noticed unless the TA display is included in the routine instrument scan.
(d) When this mode is selected, TAs will be issued at the time an RA is normally issued.
h. Crew Coordination.
(1) Objective. To verify the pilot adequately briefs other crew members on how TCAS advisories will be handled.
(2) Criteria. The pilot must demonstrate their preflight briefing addresses the procedures that will be used in responding to TAs and RAs including:
(a) Division of duties between Pilot Flying (PF) and pilot monitoring (PM).
(b) Expected callouts.
(c) Communications with ATC.
(d) Conditions under which an RA may not be followed and who will make this decision.
NOTE: Different operators have different procedures for conducting preflight briefings and for responding to TCAS advisories. These factors should be taken into consideration when implementing the training program.
NOTE: The operator must specify the conditions under which an RA need not be followed, reflecting advice published by the State Civil Aviation Authority (CAA). This should not be an item left to the discretion of a crew.
NOTE: This portion of the training may be combined with other training such as Crew Resource Management (CRM).
i. Reporting Requirements.
(1) Objective. To verify the pilot is aware of the requirements for reporting RAs to the controller and other authorities.
(2) Criteria. The pilot must demonstrate the following:
(a) The use of the phraseology contained in PANS-RAC (ICAO DOC. 4444).
Appendix 5
(b) Where information can be obtained regarding the need for making written reports to various states when an RA is issued. Various states have different reporting requirements and the material available to the pilot should be tailored to the airline’s operating environment.
j. TCAS Flight Training (Maneuver). The scenarios included in the maneuver training should include corrective RAs, initial preventive RAs, maintain rate RAs, altitude crossing RAs, increase rate RAs, RA reversals, weakening RAs, and multi-aircraft encounters. Training must provide pilots the opportunity to reach the TCAS proficiency indicated in the following TA and RA response objectives. A TCAS qualified instructor may assess and certify this proficiency.
k. TA Responses.
(1) Objective. To verify the pilot properly interprets and responds to TAs.
(2) Criteria. The pilot must demonstrate the following:
(a) The PF should continue to fly the airplane, and be prepared to respond to any RA that might follow. The PM should provide updates on the traffic location shown on the TCAS display, using this information to help visually acquire the intruder.
(b) Both pilots confirm that the aircraft they have visually acquired is that which has caused the TA to be issued. Use should be made of all information shown on the display, note being taken of the bearing and range of the intruder (amber circle), whether it is above or below (data tag), and its VS direction (trend arrow).
(c) Other available information is used to assist in visual acquisition. This includes ATC party-line information, traffic flow in use, etc.
(d) Because of the limitations that may exist with various display systems, the PF should not maneuver the aircraft based solely on the information shown on the TCAS display.
No attempt should be made to adjust the current flightpath in anticipation of what an RA would advise.
(e) When visual acquisition is attained, right-of-way rules are used to maintain or attain safe separation. Do not initiate unnecessary maneuvers. The limitations of making maneuvers based solely on visual acquisition, especially at high altitude or without a definite horizon, are understood.
l. RA Responses.
(1) Objective. To verify the pilot properly interprets and responds to RAs.
(2) Criteria. The pilot must demonstrate the following:
(a) The PF responds to the RA with positive control inputs, when required, while the PM provides updates on the traffic location and cross-checks between the traffic display and monitors the response to the RA. Use proper CRM.
Appendix 5
(b) Proper interpretation of the displayed information means the pilot recognizes the intruder causing the issuance of the RA (red square on display). Pilot responds appropriately.
(c) For corrective RAs, the response is initiated in the proper direction within 5 seconds of the RA being displayed.
(d) Recognition of the initially displayed RA being modified. Response to the modified RA is properly accomplished.
1. For increase rate RAs, the VS is increased within 2 1/2 seconds of the RA being displayed.
2. For RA reversals, the VS is reversed within 2 1/2 seconds of the RA being displayed.
3. For RA weakenings, the VS is modified to initiate a return towards the original clearance within 2 1/2 seconds of the RA being displayed.
4. For RAs which strengthen, the VS is modified to comply with the revised RA within 2 1/2 seconds of the RA being displayed.
(e) Recognition of altitude crossing encounters and the proper response to these RAs.
(f) For preventive RAs, the VS needle remains outside the red area on the RA display.
(g) For maintain rate RAs, the VS is not reduced. Pilots should recognize that a maintain rate RA may result in crossing through the intruder’s altitude.
(h) If a decision is made to not follow an RA, no changes in the existing VS are made in a direction opposite to the sense of the displayed RA. Pilots should be aware that if the intruder is also TCAS equipped, the decision to not follow an RA may result in a decrease in separation at CPA because of the intruder’s RA response.
(i) When the RA weakens, pilot initiates a return towards the original clearance, and when clear of conflict is annunciated, pilot completes the return to the original clearance.
(j) Inform the controller of the RA as soon as time and workload permit, using the standard phraseology.
(k) When possible, comply with an ATC clearance while responding to an RA. For example, if the aircraft can level at the assigned altitude while responding to a reduce climb or reduce descent RA, it should be done.
(l) If pilots simultaneously receive instructions to maneuver from ATC and an RA that are in conflict, the pilot should follow the RA.
Appendix 5
(m) Knowledge of the TCAS multi-aircraft logic and its limitations is important. For example, TCAS only considers intruders that it believes to be a threat when selecting an RA. As such, it is possible for TCAS to issue an RA against one intruder that results in a maneuver towards another intruder that is not classified as a threat. If the second intruder becomes a threat, the RA will be modified to provide separation from that intruder.
(n) The consequences of both responding to, and not responding to, an RA.
m. Characteristics of Training Equipment Suitable for Maneuver Training.
(1) Acceptable Characteristics. FTDs, simulators, and CBIs must have certain characteristics to be effective. This is due to the interactive nature of TCAS, the variety of encounter scenarios possible, the immediate and standardized pilot response required, and the instant and correct display interpretation that is necessary. Thus, training equipment used for TCAS flight training should have the following characteristics:
(a) The ability to functionally represent TCAS displays, controls, indications, and annunciations;
(b) Ability to depict selected traffic encounter scenarios, including TCAS display and audio advisories;
(c) Ability to show proper TCAS reaction to depicted scenarios and advisories; and
(d) Ability to interactively respond to pilot inputs regarding TCAS advisories, including responses to RAs displayed on relevant VS and pitch indicators.
(2) Simulator and TCAS Fidelity. For a particular TCAS, one may accomplish maneuver training in TCAS-qualified simulators or FTDs that represent the specific aircraft or an aircraft that has similar characteristics. For the purposes of TCAS maneuver training, simulators or FTDs may use simplified TCAS algorithms or displays and do not require TCAS logic or a TCAS processor. TCAS displays do not have to be identical, but must be functionally equivalent to the air carrier operator’s specific aircraft in use.
(3) Flight Training Device or Simulator Approval. The National Simulator Program (NSP) qualifies Flight Simulator Training Devices (FSTD) as meeting Title 14 of the Code of Federal Regulations (14 CFR) part 60 requirements and the POI approves them for use in a training program. Any one or combination of the following TCAS-qualified devices which meet characteristics of subparagraph 3m(1) may be used:
• Level A through D simulators;
• Level 4 through 7 FTDs; or
• Other TCAS training devices which are shown to be suitable for TCAS training and are approved by the POI.