Appendix A Table A-3B. Above/Norm/Below Switch ABOVE Displays altitude-reporting traffic from 2700 feet below to 9900 feet above the TCAS II aircraft. The selection of this mode is annunciated by ABOVE being displayed on the traffic display. This selection has no effect on the functioning of the collision avoidance logic.
NORM Displays altitude reporting traffic from 2700 feet below to 2700 feet above the TCAS II aircraft.
BELOW Displays altitude-reporting traffic from 2700 feet above to 9900 feet below the TCAS II aircraft. The selection of this mode is annunciated by BELOW being displayed on the traffic display. This selection has no effect on the functioning of the collision avoidance logic.
OFF-SCALE TRAFFIC ADVISORY - If TCAS II tracks an intruder that is outside the selected range of the display but that has entered the Caution or Warning areas, one-half of the appropriate symbol will appear at the appropriate bearing at the edge of the display area. The symbol will appear in its proper color and have its data tag displayed, providing there is room.
For example, a TA intruder with a high closure rate, and which is directly ahead and 300 feet below your airplane will appear as an amber-filled half circle at the 12 o’clock position on the edge of the display area. The data tag “-03” will appear below the half symbol. If this intruder is above your altitude, the data tag is not visible. An off-scale RA intruder will appear as a redfilled half square with data tag displayed if room permits.
NO BEARING ADVISORIES - When TCAS II cannot track the bearing of an intruder, the traffic advisory will appear in the lower center of the display just below the own-airplane symbol. The advisory will present appropriate color-coded traffic information. This phenomenon usually is caused either by temporary antenna shielding (caused by steep bank angles) or a failure in the TCAS II bearing antenna. Up to two lines of information can be displayed. “TA 5.2 -06↑” for example means an intruder is creating a Traffic Advisory 5.2 nautical miles away, 600 feet below, and climbing in excess of 500 FPM. This advisory is written in amber or yellow. “RA 0.6 00” means resolution advisory traffic is 0.6 nautical miles away at the same altitude. This advisory is written in red. TCAS II’s ability to compute a traffic or resolution advisory is not degraded by lack of bearing information.
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Appendix A Figure A-4. TCAS II Instantaneous Vertical Speed Indicator (Example) Red Arc Green Arc Key to Colors in Figures A-8
Appendix A Table A-1. Instantaneous Vertical Speed Indicator Indicates vertical speed in feet per minute. The IVSI is a normal instantaneous vertical speed indicator, and the presence of the lights or the flags will not interfere with the ability of the needle to indicate vertical speeds.
RED/GREEN EYEBROW LIGHTS. Eyebrow lights are invisible until they illuminate as part of a TCAS II “RESOLUTION ADVISORY”, or system “TEST”. These lights indicate a vertical speed regime which will provide safe traffic separation. The green lights form a wider band than red lights.
IVSI Status Window Flags T C BLACK. Normal operation. A S T C AMBER FLAG. Indicates Unusable TCAS II information. A S RT WHITE “RA OFF” FLAG. Always displayed when TCAS
A C II/TRANSPONDER function selector is in STBY, XPDR, or TA. Will also OA be displayed with selector in RA/TA if “RAs” are inhibited and/or FS inoperative.
F
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Appendix A Figure A-5. TCAS II Examples - Preventive RAS NOTE: No change in vertical speed is required when these RAs are issued.
VERTICAL VERTICAL
SPEED SPEED
(a) Preventive Aural: MONITOR VERTICAL SPEED Pilot Response: No action required Maintain the vertical speed within the green arc.
(b) Preventive Aural: MONITOR VERTICAL SPEED Pilot Response: No Action Required. If a descent is initiated, it must be limited to less than 500 fpm.
Red Arc Green Arc
VERTICAL Key to Colors in Figures SPEED
(c) Preventive Aural: MONITOR VERTICAL SPEED Pilot Response: No action required.
Descent rate cannot be greater than 2,000 fpm.
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Appendix A Figure A-6. TCAS II Examples - Initial Corrective RAS NOTE: Pilot response to these initial corrective RAs is expected within 5 seconds.
Pilots should promptly and smoothly fly to the green arc.
VERTICAL VERTICAL
SPEED SPEED
(a) Corrective Aural: DESCEND, DESCEND Pilot Response: Smoothly establish a descent rate between 1,500 fpm and 2,000 fpm
(b) Corrective Aural: CLIMB, CLIMB Pilot Response: Smoothly establish a climb rate between 1,500 fpm and 2,000 fpm.
Red Arc VERTI Green Arc SPEED Key to Colors in Figures
(c) Corrective Aural:
LEVEL OFF, LEVEL OFF Pilot Response: Smoothly reduce vertical speed to zero 1pm.
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Appendix A Figure A-7. TCAS III Examples - Modifications to Initial Corrective RAs NOTE: Pilot response to these modified RAs is expected within
2.5 seconds. Pilots should promptly and smoothly fly to the green arc.
VERTICAL VERTICAL, 6
SPEED SPEED
(a) Increase Aural: INCREASE DESCENT, INCREASE
DESCENT Pilot Response: Increase the descent rate, fly to the green arc, 2,500 fpm to 3,000 fpm
(b) Reversal Aural: CLIMB, CLIMB NOW Pilot Response: Reverse descent rate and immediately start a climb between1,500 fpm and 2,000 fpm Red Arc Green Arc
VERTICAL Key to Colors in Figures SPEED
(c) Weakening Aural:
LEVEL OFF, LEVEL OFF Pilot Response: Smoothly reduce vertical speed to between 0 and - 250 fpm.
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Appendix A SECTION I – LIMITATIONS.
(1) Pilots are authorized to deviate from their current ATC clearance to comply with a TCAS II resolution advisory (RA).
(2) Maneuvers based solely on a traffic advisory (TA) or on information displayed on the traffic display are not authorized.
SECTION II - EMERGENCY PROCEDURES.
(1) No change from basic airplane flight manual.
SECTION III – PROCEDURES.
(1) TCAS II Flight Procedures:
Compliance with a TCAS II resolution advisory (RA) is necessary unless the pilot considers it unsafe to do so, or unless the pilot has information about the cause of the RA and can maintain safe separation for example visual acquisition of, and safe separation from, a nearby aircraft on a parallel approach.
NOTE: CAUTION! Once a non-crossing RA has been issued, safe operation could be compromised if current vertical speed is changed, except as necessary to comply with the RA. This is because TCAS II-to-TCAS II coordination may be in progress with the intruder airplane, and any change in vertical speed that does not comply with the RA may negate the effectiveness of the other airplane’s compliance with its RA.
NOTE: WARNING. Noncompliance with a crossing RA by one airplane may result in reduced vertical separation; therefore, safe horizontal separation must also be assured by visual means.
Because of the limited number of inputs to TCAS II for airplane performance inhibits, in some instances where inhibiting RAs may be appropriate it is not possible to do so. In these cases, TCAS II may command maneuvers that may significantly reduce stall margins or result in stall warning. Therefore, the stall warning stick shaker must be respected when following an RA. Conditions where this may occur include:
(a) Bank angle in excess of 15 degrees.
(b) One engine inoperative.
(c) Abnormal configurations such as landing gear not retractable, etc.
(d) Leaving airplane in inappropriate configurations when climb RA occurs.
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Appendix A
(e) Operation at airports outside of 0 to 5,300 feet MSL or temperatures outside of ISA ±50°F.
(f) Speeds below normal operating speeds.
(g) Buffet margin less than 0.3 g.
The TCAS II RA algorithms are based on the pilot initiating the initial 0.25 g acceleration maneuver within approximately 5 seconds. Pilot response is expected within approximately 2.5 seconds if an additional RA is issued. (The increase rate and rate reversal RAs are based on a
0.35 g acceleration maneuver.) Because of these requirements and the rate limits of the autopilots, all RA responses must be hand-flown and not with the autopilot or autothrottles engaged.
NOTE: Evasive maneuvering should be limited to the minimum required to comply with the RA. Excessive responses to RAs are not desirable or appropriate because of other potential traffic and ATC consequences. From level flight, proper response to an RA typically results in an overall altitude deviation of 300 to 500 feet in order to successfully resolve a traffic conflict.
Modified advisories are posted after the response to an initial advisory has been completed and the TCAS II airplane is projected to have adequate altitude separation from the intruder. The initial RA is said to weaken, indicating a return towards the original flight path or clearance is allowed. When the initial advisory weakens, the green arc is repositioned to indicate level flight, the magnitude of the red arc decreased, and “LEVEL OFF, LEVEL OFF” is announced. The modified RA indicates a return to level flight so that the altitude displacement in response to the initial RA can be minimized. This RA will remain displayed until the “CLEAR OF CONFLICT” aural annunciation is issued. Following the weakening advisory will greatly reduce the ultimate altitude deviation caused by the original corrective resolution advisory.
If a “CLIMB” RA is issued while in the landing configuration, initiate normal go-around procedures.
NOTE: Initiating go-around procedure for a “CLIMB” RA does not mandate a missed approach. It is intended to ensure the airplane is properly configured for the TCAS II maneuver. In most cases, the TCAS II event will be resolved with only minor deviation to the intended flight path, and sufficient time and altitude may exist to recover safely to the desired flight path.
The pilot should not initiate evasive maneuvers using information from the traffic display only or on a traffic advisory (TA) only without visually sighting the traffic. These displays and advisories are intended only for assistance in visually locating the traffic and lack the flight path trends necessary for use in evasive maneuvering. However, unnecessary resolution advisories can be issued by TCAS II when other aircraft are operating at an altitude adjacent to the one that has been assigned to the climbing or descending TCAS aircraft. When climbing or descending A-14
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.
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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.
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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.
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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.
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