(viii) Evaluate all selectable modes of the TCAS II to determine that they perform their intended function.
(ix) Reevaluate any previously installed aircraft systems that have required changes as a result of the TCAS II installation (e.g., EFIS, FD, PFD, ND, IVSI, interface, etc.)
h. Airplane Flight Manual Supplement (AFMS). The AFMS should provide the appropriate system limitations and procedures, and a comprehensive description of all normal modes of operation including what actions are expected by the flightcrew in each case. Appendix 1 provides an example of the elements and extent of detail that may be shown by a typical AFMS (specific performance data and procedures may vary with system design and OPERATIONAL APPROVAL. Operational approval of TCAS II is addressed by AC 120-55.
28 Par 3
Appendix 1 APPENDIX 1 Descriptive material and procedures contained in this AFMS example may, when appropriate, be replaced by reference in the AFMS to the TCAS II equipment supplier's pilot's operating guide. However, the AFMS reference to this guide must be specitic; l.e., date, revision level; and not openended, e.g.
later revision'; unless the pilot's guide is specifically FAA approved. Also, the AFMS must define the specific configuration approved from the various options contained in the pilot's guide; e.g., which model control panel, whether the pilot-initiated self-test is available in flight, range features, TA vertical display features, etc.
AIRPLANE FLIGHT MANUAL SUPPLEMENT (Example)
DESCRIPTION The TCAS II is an on-board collision avoidance and traffic situation display system with computer processing to identify and display intruding and threatening collision aircraft, and issue resolution advisories in the torm oi vertical maneuver quidance on the pilot and copilot's instantaneous vertical speed indicators (IVSI). From the transponder replies, TCAS II determines relative altitude, range, and bearing of any ATCRBS or Mode S equipped aircraft with altitude reporting. From this, TCAS Il will determine the level of advisory using standardized algorithms. The TCAS II will resolve multiple aircraft encounters. ATCRBS equipped aircraft which only reply with Mode A information will not provide altitude information; therefore, TCAS II will not issue resolution advisories for these aircraft but can issue traffic advisories. The TCAS II will not detect aircraft without transponders.
The TCAS II installation consists of one TCAS I processor, one top-mounted directional antenna, one bottom-mounted blade (or directional antenna), one Mode S transponder with control panel and top and bottom antennas, one traffic advisory display with control panel (if not combined with the IVSI/RA indicators), two resolution advisory displays, one overhead speaker for voice messages, (caution/warning lights), and associated wiring.
The TCAS II provides two levels of advisories:
If the traffic gets within 25 to 45 seconds, depending upon altitude, of projected Closest Point of Approach (CPA), it is then considered an intruder, and an aural and visual traffic advisory (TA) is issued. This level calls attention to what may develop into a collision threat using the traffic advisory display and the voice message, "TRAFFIC-TRAFFIC."
It permits mental and physical preparation for a possible maneuver to follow and assists the pilot in achieving visual acquisition of the intruding aircraft.
If the intruder gets within 20 to 35 seconds, depending upon altitude, of CPA, it is considered a threat, and an aural and visual resolution advisory (RA) is issued. This level provides a recommended vertical maneuver using modified IVSIs and voice messages to provide adequate vertical separation from the threat aircraft or prevents initiation of a maneuver that would place the TCAS II aircraft in jeopardy.
Appendix 1 The TCAS II is considered a back-up system to the "SEE-AND-AVOID" concept and the ATC radar environment.
The TCAS II resolution advisories are annunciated by the following voice messages, as appropriate, along with the expected pilot response:
(A) "CLIMB, CLIMB, CLIMB" (Climb at the rate depicted by the green (fly to) arc on the IVSI.)
B) "DESCEND, DESCEND, DESCEND" (Descend at the rate depicted by the green (fly to) arc.)
(C) "MONITOR VERTICAL SPEED-MONITOR VERTICAL SPEED" (Spoken only once if softening from a previous corrective advisory.) Assure that vertical speed is out of the illuminated IVSI red arc.
(D) "REDUCE CLIMB-REDUCE CLIMB" (Reduce vertical speed to a value within the illuminated green arc.)
(E) "CLEAR OF CONFLICT" (Range is increasing, and separation is adequate; expeditiously return to the applicable ATC clearance, unless otherwise directed by ATC.)
(F) "CLIMB, CROSSING CLIMB, CLIMB, CROSSING CLIMB" (Climb at the rate depicted by the green (fly to) arc on the IVSI. Safe separation will best be achieved by climbing through the threat's flight path.
(G) "REDUCE DESCENT-REDUCE DESCENT" (Reduce vertical speed to a value within the illuminated green arc.)
(H) "DESCEND, CROSSING DESCEND, DESCEND, CROSSING DESCEND" (Descend at the rate depicted by the green (fly to) arc on the IVSI.) Safe separation will best be achieved by descending through the intruder's flight The following voice messages annunciate enhanced TCAS II maneuvers when the initial RA does not provide sufficient vertical separation. The tone and inflection connote increased urgency.
(A) "INCREASE CLIMB, INCREASE CLIMB" (Climb at the rate depicted by the green (fly to) arc on the IVSI.) Received after "CLIMB" advisory, and indicates additional climb rate required to achieve safe vertical separation from a maneuvering threat aircraft.
(B) "INCREASE DESCENT, INCREASE DESCENT" (Descend at the rate depicted by the green (fly to) arc on the IVSI.) Received after "DESCEND" advisory, and indicates additional descent rate required to achieve safe vertical separation from a maneuvering threat aircraft.
(C) "CLIMB - CLIMB NOW, CLIMB - CLIMB NOW" (Climb at the rate depicted by the green (fly to) arc on the IVSI.) Received after a "DESCEND" resolution advisory and indicates a reversal in sense is required to achieve safe vertical separation from a maneuvering threat aircraft.
Appendix 1 (D) "DESCEND - DESCEND NOW, DESCEND - DESCEND NOW" (Descend at the rate depicted by the green (fly to) arc on the IVSI.)
Received after a "CLIMB" resolution advisory and indicates a reversal in sense is required to achieve safe vertical separation from a maneuvering threat aircraft.
Appendix 1 Figure 1: TCAS/Transponder Control Panel (Example).
Warning Light (Amber) Code Indicator
STBY XPDR ALT RPTG
TCAS/ TEST OFF ON Transponder Function IDENT Selector TA/RA 1 2 1|5
ATC XPDR TCAS XPDR FAIL Code Selectors TCAS/Transponder Function Selector TEST Holding the TCAS/Transponder function selector in TEST for 2 to 3 seconds will activate the system test sequence. In the TEST position, maintenance messages may be read on the display. Discretion must be used when selecting TEST in flight, since both TCAS Il and the Transponder will be inhibited for approximately 20 seconds. The function selector is spring loaded to STBY.
STBY Activates TCAS Il and XPDR warmup cycles.
XPDR Transponder is on. TCAS Il is in warmup cycle.
TA Transponder is on. Only the "TRAFFIC ADVISORY", or "TA", function of the TCAS Il is on. No "RESOLUTION ADVISORIES" will be received in this position. The written warning "TA ONLY" will appear on the display, and the yellow "RA OFF" flag will be in view on both IVSI's TA/RA Transponder is on. All TCAS Il functions are on. No TCAS flags should be present on either IVSI.
XPDR Fail Indicates a transponder system failure when the transponder is on. Comes on Light (Red) during "TEST", but goes off after approximately 3 seconds if the transponder is Code Indicates code selected with the code selectors. Warning Light (Amber) Indicator Indicates both transponders are on.
IDENT Causes the word INDENT to flash in the aircraft data block on the ATC display.
ALT RPTG Provides automatic altitude reporting of ATC.
Code Select the transponder code. Left and right selectors consist of a large knob Selectors and a small knob. Each controls one digit of the code.
3/29/93 AC 20-131A Appendix l Figure 2: TCAS II - Traffic Display (Example).
20nm REL ALT 20 ABOVE BRT NORM
BELOW OFF MAX RANGE Arrows indicate that the target is climbing 1 or descending + at a rate of at least 500 fpm.
Relative altitude in displayed in the proximity of the aircraft symbol in hundreds of feet. A"+" preceding the relative altitude indicates the target is above you, and a "" indicates it is below you.
Displayed Aircraft Symbols (Examples) Unfilled white diamond. Non-threatening traffic without altitude reporting. If altitude reporting, the altitude data will be displayed.
Solid white diamond. Proximity traffic 700 feet above. Non-threatening, altitude + 07 reporting traffic within 1200 feet vertically and 6nm horizontally. Aircraft without altitude reporting will be assumed to be co-altitude and will be displayed as a solid diamond when within 6nm even though they may not be within 1200 feet vertically.
Solid yellow circle. "TA", 300 feet below, descending. At least 500 FPM.
-03 + 00 Solid red square. "RA", level at your altitude.
Ownship. Airplane symbol in white just below the center of CRT. On a dedicated display or when in the TFC Mode on a combination TCAS/RADAR Display.
(Compass This arc is a repeater of the Captains compass. (Not required for a TCAS I Arc) Display).
(Hange 3nm - Small ring with ticks at clock positions 5 NM - Large ring made of dots.
Rings) 5
AC 20-131A Appendix l 3/29/93 Figure 2: TCAS II - Traffic Display (Example) (Con't).
20nm 30 10 REL ALT 20 ABOVE BAT NORM
BELOW OFF MAX RANGE Paddle Switch REL ALT/EL Switch REL ALT Paddle switch is spring loaded to the center position. Display shows REL ALT in hundreds of feet above (+) or below (-) your aircraft.
FL Momentary contact allows display of traffic flight levels, referenced to 29.92, for 15 seconds. Your FL is displayed in lower left corner. Three digits are shown, except for negative flight levels which are shown as -xx RANGE The compass arc is always set at range selected by the range knob. Ranges of 3, 5, 10 or 20 nm are selected.
BRT Knob Controls brightness of the displays.
Above/Norm/Below Switch.
ABOVE Displays altitude reporting traffic from 2700 feet below to 9900 feet above.
NORM Displays altitude reporting traffic from 2700 feet below to 2700 feet above.
BELOW Displays altitude reporting traffic from 2700 feet above to 9900 feet below.
3/29/93 AC 20-131A Appendix 1 Figure 2: TCAS II - Traffic Display (Example) (Cont).
OFF-SCALE TRAFFIC ADVISORY In the event that TCAS II tracks an intruder that is outside the range of the display but 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 is 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 red-filled half square with data tag, if possible.
NO BEARING ADVISORIES If and when TCAS II is unable to 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 TCA „TA 5.2-061" for example means an intruder is creating Il bearing antenna. Up to two lines of information can be displayed.
a Traffic Advisory 5.2 nautical miles away, 600 feet below, and climbing in excess of 500 FPM. "RA 0.6 00" means resolution advisory traffic is
0.6 nautical miles away at the same altitude. TCAS II's ability to compute a Traffic or Resolution Advisory is NOI degraded by lack of bearing information.
Appendix 1 Figure 3: TCAS II Instantaneous Vertical Speed Indicator (Example)
VERTICAL SPEED 4 2 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.
C 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 the red lights.
IVSI Status Window Flags BLACK. Normal operation.
S T AMBER FLAG. Indicates unusable TCAS Il information.
C S T RA WHITE "RA OFF" FLAG. Always displayed when TCAS/TRANSPONDER C function selector is in STBY, XPDR, or TA. Will also be displayed with selector _A in RA/TA in "RAs" are inhibited and/or inoperative.
S F
AC 20-131A 3/29/93 Appendix 1 Figure 4: TCAS I/ Examples - Preventive.
Red Green VERTICAL : VERTICAL
SPEED SPEED
(a) Preventive (b) Preventive MONITOR VERTICAL SPEED MONITOR VERTICAL SPEED.
Note: This multi-aircraft encounter is the only preventive RA that displays a green arc.
VERTICAL VERTICAL
SPEED SPEED
(c) Preventive (d) Preventive MONITOR VERTICAL SPEED. MONITOR VERICAL SPEED.
Appendix 1 Figure 5: TCAS II Examples - Corrective.
Red Green
VERTICAL VERTICAL
SPEED SPEED
(a) Corrective (b) Corrective DESCEND. CLIMB or CLIMB, CLIMB NOW.
VERTICAL VERTICAL 6
SPEED SPEED S
(c) -Corrective (d) Corrective INCREASE DESCENT. REDUCE CLIMB.
3/29/93 AC 20-131A Appendix 1 SECTION 1 - LIMITATIONS o Pilots are authorized to deviate from their current ATC clearance to the extent necessary to comply with a TCAS II resolution advisory (RA).
SECTION II - EMERGENCY PROCEDURES o No change from basic airplane flight manual.
SECTION III - PROCEDURES ICAS II Flight Procedures:
o Compliance with a TCAS II resolution advisory (RA) is necessary unless the pilot considers it unsafe to do so, or unless the pilot has better information about the cause of the RA and can maintain safe separation
(e.g., visual acquisition of and safe separation from a nearby aircraft, obvious TCAS II system failure, etc.).
CAUTION Once a noncrossing 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.
**** * * * * * WARNING * * * * * * * * * *
- Noncompliance with a crossing RA by one airplane may result in reduced vertical separation; theretore, sate horizontal separation must also be assured by visual means.
NOTE The consequences of not following an RA may result in additional RAs in which aural alert and visual annunciations may not agree with each other.
o Because of the limited number of inputs to TCAS II for airplane pertormance inhibits, in some instances where inhibiting RAs may be appropriate it is not possible to do so. in these cases, ICAS ll may command maneuvers which 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: