approved by the FAA for that operator's specific TCAS systems, training devices, and simulators.
(1) Programs Addressing TCAS Maneuvers Through Use of Approved Simulators or Training Devices. Programs based on use of FAA-approved training devices or simulators should realistically depict relevant aspects of TCAS procedures, encounters, and pilot responses. This may be accomplished using one or more of a combination of training methods described in paragraph 8a.
simulator or training device used should have the characteristics described in paragraph 8(m).
Programs Addressing TCAS Maneuvers Through Use of CBI.
TCAS programs may be approved which do not require using approved simulators or training devices if the proposed program meets certain criteria as described in 8c(2) (i)-(ii). These programs are based on CBI adequately depicting TCAS procedures, traffic encounters, desired pilot responses, and resulting maneuvers. Such programs may approved if the program otherwise addresses the issues identified in 8c (1), and is consistent with the following criteria:
(i) TCAS systems, displays, and procedures must be consistent with accepted FAA and industry guidelines. There must not be any significant adverse training experience related to the particular TCAS system (s) to be used.
(i1) The program must realistically depict TCAS encounter scenarios. Scenarios must demonstrate proper TCAS procedures: depict "real time" (dynamic) traffic encounters:
represent correct indications for TA's, RA's, displayed traffic and aural messages; and require proper pilot responses to RA's displayed on relevant vertical speed and pitch indicators.
d. Training Center Approval. Training centers conducting training (e.g., contract training, aircraft manufacturers, etc.) may have TCAS elements of those programs approved if:
(1) Provisions of 8b and 8c are shown to be met, or
(2) Equivalence to a previously approved program can be established. In this instance, circumstances, assumptions, and conditions for the program's use must also be equivalent to those applicable to the previously approved program.
Initial Evaluation of TCAS Knowledge and Procedures.
Individual crewmember TCAS knowledge and procedures should be evaluated prior to TCAS use. Acceptable means of initial assessment include:
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(1) Evaluation by an authorized instructor or check airman using a simulator or a training device capable of depicting traffic encounters, or
(2) Evaluation by an authorized instructor or check airman during line operations, training flights, PC/PT events, operating experience (OE), route checks, line checks, or
(3) Computer-based testing in which TCAS scenarios and advisories are depicted, and for which a record documents acceptable pilot performance, or
(4) Other alternate methods acceptable to the Administrator.
Alternate methods must demonstrate the equivalent effectiveness of methods described in 8e(1) - (3).
(5) If instructors are TCAS-qualified, they may be make be authorized to conduct the required initial TCAS crewmember evaluations.
I. ICAS Recurrent Training. TCAS recurrent training should be integrated into and/or conducted in conjunction with other established recurrent training programs. Recurrent training for TCAS should include maneuver training meeting the requirements of paragraph 8(c) and should address any significant issues identified by line operating experience, system changes, procedural changes, or unique characteristics.
g. ICAS Recurrent Evaluation. Recurrent TCAS checking should be incorporated as necessary as an element of routine proficiency training or proficiency check programs.
h. TCAS Currency (Recency of Experience). Once crews have completed initial TCAS training and as long as recurrent training is accomplished in accordance with paragraph 8f, specific TCAS currency requirements are not necessary.
i. Line Checks and Route Checks. When TCAS-equipped aircraft are used during line or route checks, check airmen should routinely incorporate proper TCAS use as a discussion item.
j. LOFT. LOFT programs using simulators equipped with TCAS should be enhanced by interaction with ICAS. In addition, LOFT programs should consider proper crew vigilance for aircraft which may not be transponder or Mode C-equipped.
k. Crew Resource Management (CRM). CRM programs should address effective teamwork in responding to TCAS events.
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1. TCAS Academic Training Methods. Appropriate methods may be suited to each air carrier's program. No special methods related to academic training for TCAS are identified. Typically, a combination of ground instruction, manual information, flightcrew bulletins, and other such means is appropriate to address academic topics specified in paragraph 8b, Academic Training.
m. Characteristics of Simulated TCAS Systems for Maneuver Training.
(1) Acceptable Characteristics. Training devices and simulators should 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 reguired, and the instant and correct display interpretation that is necessary. Thus, simulators or training devices used for TCAS training should have the following characteristics:
(i) The ability to functionally represent TCAS displays, controls, indications, and annunciations.
(ii) Ability to depict selected traffic encounter scenarios including TCAS display and audio advisories.
(iii) Ability to show proper ICAS reaction to depicted scenarios and advisories.
(iv) Ability to interactively respond to pilot inputs regarding TCAS advisories including responses to RA's displayed on relevant vertical speed and pitch indicators.
(2) Simulator and TCAS System Fidelity. For a particular TCAS system, maneuver training may be accomplished in simulators or training devices which represent the specific aircraft or an aircraft that has similar characteristics.
training, simulators or training devices may use simplified algorithms or displays. ICAS displays do not have to be identical, but must be functionally equivalent to the air carrier operator's specific aircraft in use.
(3) Training Device or Simulator Approval.* Training devices or simulators meeting FAA criteria are qualified by the NSET and approved for use by the POI. Any one or combination of the following devices or simulators which meet characteristics of paragraph 8m(1), Acceptable Characteristics, may be used:
(i) Level A through D Simulators,
(ii) Level 2 through 7 flight training devices, or Par 8 15
AC 120-55A 8/27/93
(iii) Dedicated TCAS training devices acceptable to the FAA (including those devices described in FAA Order 8400.10, Air Transportation Operations Inspector's Handbook, Volume 3, paragraph 443, "Aircraft Systems Integration Training" which are shown to be suitable for TCAS training).
*NOTE - Training Device and Simulator Levels are as defined by AC 120-40B, Airplane Simulator Qualification;
AC 120-54, Advanced Qualification Program; and FAA Order 8400.10.
9. OTHER OPERATIONAL ISSUES.
Manuals and Other Publications. Airplane flight manuals, operating manuals, maintenance manuals, general policy manuals, or other manuals, publications, or written materials (e.g., operating bulletins) that may relate to TCAS use must be appropriately amended to describe TCAS equipment, procedures, and operational policies according to the appropriate FAR.
b. MMEL MEL.
General. Operators formulate necessary TCAS revisions to their MEL(s) for each particular fleet (e.g., B727, DC10, etc.).
MEL revisions must be consistent with the FAA MMEL established for each aircraft type. A summary of the process for addressing the necessary changes to MEL items as well as examples of MMEL and acceptable MEL provisions for TCAS are provided in appendix 2.
Inoperative TCAS During the TCAS Transition Program (TTP). During the TTP and prior to final TCAS FAR compliance resolved TeAS tranel tion jever ind have developed eifEsSen TAS.
experience to properly apply MMEL and MEL requirements. From the time of the first TCAS installation, operators are encouraged to apply anticipated MMEL provisions to gain experience with TCAS inoperative component issues.
c. Aircraft with TCAS System Differences. Operators having aircraft with TCAS system differences in displays, controls, or procedures, or invoived with interchange operations, must account for those TCAS system differences. This is accomplished as part of an approved differences training program in accordance with FAR Part 121, or as otherwise specified in applicable FAA FSB reports concerning crew qualification pertaining to a particular airplane Par 8 16
d. Issues Unique to a Particular Operator. Operators should address any TCAS issues that may be unique to their particular route environment, aircrait, procedures, or TCAS display and control features. Examples include the following:
(1) Example of a "Route Environment" Issue. Air carriers having takeoffs or landings outside of the reference TCAS performance advise crews of appropriate procedures and precautions regarding RA compliance. To ensure proper response to TCAS in limiting performance conditions (e.g., TCAS RA during "takeoff climb" or in "final landing" configuration at high altitude airports such as exico City, la Paz, etc.), specific procedures or training may be needed unless these situations can be adequately addressed by bulletin or manual information.
(2) Example of a "Procedural" Issue. Air carriers should describe any TCAS precautions that may be appropriate when operating in countries where transponder, Mode S, or TCAS policies are uncertain. In those cases, carriers should conform to the laws and regulations that govern the airspace being used. This guidance should be reflected in company flight operations manuals.
Example of a "Unique TCAS System" Issue. TCAS "flight level" or "absolute" display of traffic altitude on a traffic display should not be used during operations when the altimeter is set to zero relative to the intended field of landing.
10. MAINTENANCE.
a. General. Maintenance procedures for TCAS are approved or accepted as part of an operator's initial maintenance manual approval or as a revision to that manual. TCAS maintenance procedures should be consistent with the TCAS manufacturer's maintenance procedures and/or aircraft manufacturer's maintenance procedures for TCAS.
b. Maintenance Training. An operator must provide adequate TCAS maintenance training in accordance with the appropriate FAR to ensure that its maintenance personnel or contract maintenance personnel at facilities not staffed by the operator are able to properly implement TCAS-related maintenance programs.
and "return to service" authorizations. The training procedures should address testing installed transponders and automatic pressure altitude reporting equipment on the ground in such a way that false targets are not generated in airborne TCAS systems. A method for Par 9 17
elimination of the potential for interfering with TCAS-equipped aircraft during transponder testing would be the use of shields for the transponder antennas.
TCAS System Software Updates. Operators should ensure that appropriate TCAS software updates are incorporated when necessary.
11. ICAS OPERATIONAL USE.
a. General. Operationally, those skills addressed and the guidance provided in the TCAS training paragraph 8 will be followed and implemented by each operator electing to use TCAS II and apply the appropriate FAR.
b. Pilot Responsibilities. TCAS is intended to serve as a backup (safety net) to visual collision avoidance, application of "right-of-way rules," and air traffic separation service. For TCAS to work as designed, immediate and correct crew response to ICAS advisories is essential. Delayed crew response or reluctance of a flightcrew to adjust the aircraft's flightpath as advised by TCAS due to ATC clearance provisions, fear of later FAA scrutiny, or other factors could significantly decrease or negate the protection afforded by TCAS. Flightcrews are expected to respond to TCAS in accordance with the following guidelines when responding to alerts:
Respond to TA's by attempting to establish visual contact with the intruder aircraft and other aircraft which may be in the vicinity. Coordinate to the degree possible with other crewmembers to assist in searching for traffic. Do not deviate from an assigned clearance based only on "TA" information. for any traffic that is acquired visually, continue to maintain or attain safe separation in accordance with current FAR and good operating practices.
(2) When an RA occurs, the pilot flying should respond immediately by direct attention to RA displays and should maneuver as indicated unless doing so would jeopardize the safe operation of the flight or unless the flightcrew has definitive visual acquisition of
(3) Satisfy RA's, using prompt, positive control inputs in the direction and with the magnitude TCAS advises (normally 1,500 fpm climb or descent is all that is required). For TCAS to provide safe vertical separation, initial vertical speed response is expected within 5 seconds of when the RA is first displayed. Excursions from assigned altitude, when responding to an RA, typically should be no more than 300 to 500 feet to satisfy the conflict. Vertical speed responses should be made to avoid red arcs or outlined pitch avoidance areas, and, if applicable, to accurately fly to the green arc or outlined pitch guidance area.
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Respond immediately to any "increase" or "reversal" RA maneuver advisories. Initial vertical speed response to an increase or reversal RA is expected by TCAS within 2 1/2 seconds after issuance of the advisory. Again, avoid red arcs or outlined pitch avoidance areas and fly to the green arc or outlined. pitch guidance
(5) The nonflying pilot should advise the pilot flying when there is a deviation from the vertical flightpath indicated by TCAS.
The nonflying pilot, and any onboard observers, also will assist in the visual search for the intruder and continue to cross-check the TCAS displayed information with other available traffic information to ensure the RA response is being flown correctly.
(6) If an initial corrective RA is downgraded or weakened
(e.g., a climb RA downgrades to a Do Not Descend RA), pilots should respond to the weakening RA and adjust the aircraft's vertical speed accordingly but still keep the needle or pitch guidance symbol out of the red arc or outlined pitch avoidance area. Pilots are reminded that attention to the RA display and prompt reaction to the weakened RA will minimize altitude excursions and potential disruptions to This will allow for proper TCAS-to-TCAS resolution of encounters and not exacerbate or cause a "reversal" or "crossing" message.
(7) Excessive responses to TCAS RA's are inappropriate and may increase interference with other traffic.
(8) It may not be possible to respond to a TCAS RA and continue to satisfy a clearance at the same time. Even if a TCAS RA maneuver is inconsistent with the current clearance, respond appropriately to the RA. Since TCAS tracks all transponder-equipped aircraft in the vicinity, responding to an RA for an intruder assures a safe avoidance maneuver from that intruder and from other Mode C- equipped aircraft. Guidance in this paragraph does not conflict with that in paragraph 11b (2). Exceptions noted in paragraph 11b (2) are meant to hold down obvious nuisance excursions and unsafe handling of the aircraft.
If a TCAS RA requires maneuvering contrary to "right-ofway rules," "cloud clearance" rules for visual flight rules (VFR) flight, instrument flight rules (IFR), or other such criteria, pilots are expected to follow the TCAS RA's to resolve the immediate traffic conflict. Deviations from rules or clearances should be kept to the minimum necessary to satisfy a TCAS RA.
(10) If a TCAS RA response requires deviation from an ATC clearance, expeditiously return to the current ATC clearance when the traffic conflict is resolved or the TCAS message "clear of conflict" Par 11 19
is heard, or follow any subsequent change to clearance as advised by ATC. In responding to a TCAS RA that directs a deviation from assigned altitude, communicate with ATC as soon as practicable after responding to the RA. When the RA is cleared, the flightcrew should advise ATC that they are returning to their previously assigned clearance or should acknowledge the amended clearance if one is issued. In addition, the flightcrew's discretionary use of other types of reports may be desired. See appendix 5 for suggested phraseology.
(11) If a ICAS RA maneuver is contrary to other critical cockpit warnings, then those other critical warnings are respected as defined by TCAS certification and training (i.e., responses to stall warning, windshear, and GPWS take precedence over a TCAS RA, particularly when the aircraft is less than 2,500 feet above ground level).
Pilots should use TCAS traffic information displays to increase their awareness of nearby traffic and to assist in establishing visual contact with other aircraft. Certain electronic flight information system TCAS installations operating in conjunction with "track up" mode may require the pilot to make allowance for the difference between the aircraft heading and track when visually sighting nearby aircraft.
(13) Unless approved by the Administrator, pilots are expected to operate TCAS while in-flight in all airspace, including oceanic, international, and foreign airspace.
data source to provide altitude information to TCAS and the ATC transponders. Using a common altitude source precludes unnecessary RA's due to differences between altitude data sources.
(15) Note and accurately report TCAS encounters and system anomalies in accordance with operator policies so that remedial improvements to TCAS or the NAS may be initiated.
(16) ICAS does not alter or diminish the pilot's basic authority and responsibility to ensure safe flight. Since ICAS does not respond to aircraft which are not transponder-equipped or aircraft with a transponder failure, TCAS alone does not ensure safe separation in every case. Other aircraft may not be able to maneuver due to equipment malfunctions. Further, TCAS RA's may, in some cases, conflict with flightpath requirements due to terrain, such as an obstacle-limited climb segment or an approach to rising terrain.
Since many approved instrument procedures and IFR clearances are predicated on avoiding high terrain or obstacles, it is particularly important that pilots maintain situational awareness ana continue to Par 11 20
use good operating practices and judgment when following TCAS RA's.
Maintain frequent outside visual scan, "see and avoid" vigilance, and continue to communicate as needed and as appropriate with ATC.
C. The Potential Consequences of Improperly Maneuvering the Aircraft in Response to an RA Include:
(1) An aircraft seen visually may not necessarily be the aircraft causing the RA or may not be the only aircraft to which TCAS is responding.
(2) It is difficult to visually determine the vertical displacement of other aircraft especially when ground reference information is unreliable or when at cruise altitudes where the earth's horizon is obscured. Therefore, disregarding RA information and maneuvering vertically based solely on visual acquisition may result in a loss of safe separation; and
(3) ATC may not know when TCAS issues RA's. It is possible for ATC to unknowingly issue instructions that are contrary [opposite] to the TCAS RA indications. Safe vertical separation may be lost during TCAS coordination when one aircraft maneuvers opposite the vertical direction indicated by TCAS and the other aircraft maneuvers as indicated by TCAS. As a result, both aircraft may experience excessive altitude excursions in "vertical chase" scenarios due to the aircraft maneuvering in the same vertical direction. Accordingly, during an RA, do not maneuver contrary to the RA based on ATC instructions.
ATC may not be providing separation service or be communicating with the aircraft causing the RA.
NOTE: See paragraph 11d(4) (i)-(vi) for appropriate conditions to operate TCAS in the TA only mode.
operating TCAS Good Operating Practices. The following TCAS good operating practices" have been identified:
(1) To preclude unnecessary transponder interrogations and possible interference with ground radar surveillance systems, TCAS should not be activated until taking the active runway for departure.
(2) Following landing and clearing of the runway, TCAS should be selected to the "standby" or "off" mode as specified by the air carrier's operating procedures.
(3) During flight, TCAS displays should be used to enhance situational awareness. Displays which have a range selection Par 11 21
capability should be used in an appropriate range setting for the phase of flight.
(4) It is appropriate to operate TCAS in the "TA Only" mode in circumstances where unnecessary RA's frequently occur and where such RA's are disruptive to the operation of aircraft. These circumstances may include:
(i) During takeoff towards known nearby traffic which is in visual contact, and which could cause an unwanted RA during initial climb (e.g., a visually identified helicopter passing near the departure end of the runway). The TA/RA mode should be selected after the potential for an unwanted RA ceases to exist (e.g., after climbing above a known VFR corridor),
(ii) In instrument or visual conditions during approaches to closely-spaced parallel runways,
(iii) In visual conditions, when flying in close proximity to other aircraft,
(iv) At certain airports, during particular procedures, or in circumstances identified by the operator as having a significant potential for unwanted or inappropriate RA's.
In the event of particular in-flight failures, as specified by the AFM or operator, or "'TCAS reference performance" envelope for RA's, as designated by the AFM or operator ("TCAS reference performance" for RA's is typically attainable during takeoffs and landings at airports within the envelope of ISA +50 F, sea level to 5,300 feet MSL). When takeoffs or landings are outside of this envelope, use of "TA Only" may be appropriate during the limited time period when TCAS reference performance cannot be achieved. This typically occurs when the aircraft is at low speed in specified limiting configurations during takeoff or landing at "hot day" high altitude airports (e.g., Mexico City, La Paz, etc.).
(5) When safe, practical, and in accordance with the carrier s approved operating procedures, pilots should limit vertical speeds to 1,500 fpm or less when within 2,000 feet of assigned altitudes. This procedure will reduce the frequency of unnecessary
d. Operator Responsibilities. Operators have the following general responsibilities regarding TCAS:
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(1) Assure followup and evaluation of unusual TCAS events, and
(2) Periodically assess TCAS training, checking, and maintenance programs to ensure their correctness, pertinence, timeliness, and effectiveness.
e. ATC Responsibilities. ATC may not know when TCAS issues RA'S. It is possible for ATC to unknowingly issue instructions that are contrary [opposite] to the TCAS RA indications. Safe vertical separation may be lost during TCAS coordination when one aircraft maneuvers opposite the vertical direction indicated by TCAS and the other aircraft maneuvers as indicated by TCAS. As a result, both aircraft may experience excessive altitude excursions in "vertical chase scenarios due to the aircraft maneuvering in the same vertical direction. Accordingly, during an RA, the aircraft is not to maneuver contrary to the RA due to ATC instructions.
(1) When an aircraft deviates from its clearance in response to an RA, ATC is still responsible to provide assistance to the deviating aircraft as requested until:
(i) The pilot informs ATC that the RA conflict is clear; and
(ii) The aircraft has returned to the previously assigned altitude; or
(iii) Alternate ATC instructions have been issued and acknowledged.
NOTE: See appendix 5 for suggested phraseology.
(2) workload permitting, controllers may continue to provide pertinent traffic information in accordance with FAA Order 7110.65, Air Traffic Control.
(3) Controllers will not knowingly issue instructions that contrary to RA guidance when they are aware that a TCAS maneuver is in progress.
(4) Maintain awareness of TCAS programs and program changes.
(5) Train ATC specialists about TCAS and expected flightcrew responses to TCAS advisories and provide familiarization flights for specialists on TCAS-equipped aircraft to the extent possible.
(6) when requested by the flightcrew, provide separation from TCAS-observed traffic and assistance in returning to the Par 11 23
AC 120-55A 8/27/93 assigned clearance, if appropriate. Issue additional clearance instructions when the situation so requires.
(7) Advise pertinent FAA offices via TCAS questionnaires about airspace or airports where excessive numbers of RA's occur.
This facilitates initiation of corrective actions related to TCAS enhancements, TCAS procedures, and airspace adjustments.
(8) Advise FAA if aware of other hazardous conditions, situations, or events which may be related to TCAS.
12. TCAS EVENT REPORTING.
a. General. Operators and manufacturers are encouraged to develop procedures to ensure effective identification, tracking, and followup of significant TCAS-related events, as appropriate.
procedures should focus on providing useful information to:
(1) Properly assess the importance of TCAS events,
(2) Follow up on information related to specific TCAS events as necessary, and
(3) Keep the industry and FAA informed on the performance of TCAS in the NAS and in international operations.
b. Pilot Reports.
(1) "CAS-Specific" report's. Pilots should make the following reports for TCAS TA's and RA's, as necessary.
(a) Upon query from ATC, or after a deviation from an ATC clearance, make radio communications as appropriate to report a response to a TCAS advisory. Refer to the Airman's Information anual, Chapter 4, Section 4, ATC Clearance/Separations paragraph 4-81c for guidance and appendix 5 of this AC for recommended phraseology,
(b) Reports, as specified by the operator, concerning TCAS anomalies, procedural difficulties, or system failures typically are made by pilots through one or more of the following methods:
(i) Pilot/Observer Questionnaire,
(ii) Logbook entry, aircraft communications addressing and reporting system (ACARS), etc., or Par 11 24