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Traffic Alert & CollisionAvoidance System I

Model TCAS791

Pilot’s Guidefor the

Model TCAS791



TCAS791 Pilot’s GuideA

Export NoticeThis data is provided at no charge, or at cost, to thepublic and is considered publicly available, No LicenseRequired (NLR) as defined in the Export AdministrationRegulations (EAR) Part 734.7-11.

Important NoticeThis guide provides general information about the opera-tion of the TCAS791. This guide does not cover all possibleinterconnections with all possible aircraft systems andcustomer-supplied indicator lights and switches. Refer toyour aircraft flight manual and flight manual supplementfor information specific to your aircraft. If there is conflict-ing information between those manuals and this pilot’sguide, your aircraft flight manual and flight manual supple-ment take precedence over this pilot’s guide.

© Copyright 1992, 1993, 1995, 1996, 1999, 2004L-3 Communications Avionics Systems, Inc.

EYES THAT NEVER BLINK™ is a trademark of L-3 Communications Avionics Systems, Inc.Skydrol® is a registered trademark of Solutia, Inc.

The white L3 in a circle design logo is a trademark of L-3 Communications Corporation.

Designed and manufactured in the United States of America by

Methods and apparatus disclosed and described herein have been developed solely on companyfunds of L-3 Communication Avionics Systems, Inc. No government or other contractual supportor relationship whatsoever has existed which in any way affects or mitigates proprietary rights ofL-3 Communications Avionics Systems, Inc. in these developments. Methods and apparatus dis-closed herein may be subject to U.S. Patents existing or applied for. L-3 Communications AvionicsSystems, Inc. reserves the right to add, improve, modify, or withdraw functions, design modifica-tions, or products at any time without notice.

L-3 Communications Avionics Systems, Inc.5353 52nd Street, S.E.Grand Rapids, MI 49512 USA(800)253-9525 or (616)949-6600Fax (616)285-4224www.L-3com.com/as

Model TCAS791



TCAS791 Pilot’s Guideii

Eyes That Never Blink™

Early TCASIn the early days of flight, pilots were equipped with all theyneeded for effective collision avoidance–a sharp pair of eyes.But increasing traffic at higher speeds led to the develop-ment of TCAS II systems which were too expensive for mostregional airlines, business aircraft, and general aviation aircraft.

TCAS IL-3 Avionics Systems recognized the need for an alternativeto TCAS II and developed the model TCAS791 TCAS Isystem. The TCAS791 provides most of the capabilities ofTCAS II, but at a significantly lower cost making it practicalfor small aircraft. Unlike a TCAS II system, the TCAS791does not require a mode S transponder and does not issuerecommendations to climb or descend.

The FAA has mandated TCAS I for all part 135 turbineaircraft seating 10 to 30 passengers. The TCAS791 meets orexceeds all FAA TCAS I requirements and exceeds FAA TCAS I& II specifications for range and bearing accuracy.

Proven ExperienceL-3 Avionics Systems has been involved in the developmentof collision warning programs since the early 1980’s. In 1985,L-3 Avionics Systems began development of an enhancedcollision warning system for the Navy’s T-34C training aircraft.

Based largely on the success of the Navy project, L-3 AvionicsSystems was selected to validate the specifications for TCAS I.As a result, L-3 Avionics Systems’ original TCAS I unit, theTCAS791 was the first TCAS I to be granted a TechnicalStandard Order (TSO), first to receive a full, unrestrictedSupplemental Type Certificate (STC), first to fly, and first tobe delivered.

CAUTION

page 2-8

page 2-15

WARNING

page 2-8& 2-15

WARNING

TCAS791 Pilot’s Guide iii

Safety SummaryThese warnings and cautions appear later in this guide andare repeated here for emphasis:

The TCAS791 alone does not ensure safe flight. You must stillvisually scan the airspace around your aircraft frequently. TheTCAS791 relies on information obtained from transponders innearby aircraft. The TCAS791 does not detect or track aircraftwhich are not equipped with an operating ATCRBS transponder.

Do not attempt evasive maneuvers based solely on trafficinformation shown on the TCAS791 display. Informationshown on the display is provided to the aircrew only as an aidin visually acquiring traffic which may impose a collision threat. Itis not a replacement for ATC and the See & Avoid concept.

Optimum TCAS791 performance is realized when intruderaircraft are reporting their altitude (via a mode C or otheraltitude reporting transponder).

Software Version InformationAll references in this guide to standby, look up/look down,altitude display modes (above, below, and normal), andtransmitting from the ground are functions of all TCAS791systems that have software version 1.3 or higher in theirTransmitter Receiver Computer (TRC). Ignore these refer-ences if your TRC has an earlier version of software. (Thesoftware version is identified on a tag attached to the back ofthe TRC.)

Revision HighlightsThis revision G of the pilot’s guide makes the followingchanges:

• Changes occurences of “Goodrich Avionics Systems” to“L-3 Communications Avionics Systems, Inc.” or just“L-3 Avionics Systems” and makes related companycontact information changes. (On March 28, 2003,Goodrich Corporation sold its Avionics Systems divisionto L-3 Communications Corporation.)

• Eliminates the Warranty Information chapter. Warrantyinformation is now provided on a separate warrantycard.

• Separates Controls & Indicators and Operating Instruc-tions into two separate chapters.

• Adds the Export Notice, Important Notice and RevisionHighlights sections.

• Redesigns the page layout, typefaces, and font sizes forincreased readability.

TCAS791 Pilot’s Guideiv

Table of ContentsSection Page

List of Illustrations ............................. vii

List of Tables ..................................... vii

Chapter 1 System Description............ 1-1General Description ............................................................... 1-1Major Components ................................................................ 1-2

Directional Antenna .......................................................... 1-2L-Band Omnidirectional Antenna ......................................1-2Transmitter Receiver Computer (TRC) .............................. 1-2Control Display Unit (CDU)............................................. 1-3

Interaction of Major Components ........................................... 1-4Notes on Figure 1-3 ........................................................... 1-4

Functional Description ........................................................... 1-5Features ................................................................................. 1-7

Chapter 2 Controls & Indicators ......... 2-1Introduction ..........................................................................2-1Controls, Indicators, & Symbols ............................................. 2-1Aural Announcements .......................................................... 2-10

Chapter 3 Operating Instructions........ 3-1Introduction ..........................................................................3-1Turn On the TCAS791 ........................................................... 3-1Run the Operator-Initiated Self Test ........................................ 3-2Switch Out of Standby ............................................................ 3-5Switch Into Standby ............................................................... 3-6Select the Range ..................................................................... 3-6Select the Vertical Display Mode .............................................. 3-7Observe the Display ................................................................ 3-8Respond to Traffic Advisories ..................................................3-9Turn On the TCAS791 While in Flight ................................... 3-9Post-Flight Instructions......................................................... 3-10Turn Off the TCAS791 ........................................................3-10

TCAS791 Pilot’s Guide v

Section PageTable of Contents (continued)

Error Messages ..................................................................... 3-11TCAS Failed Screens .......................................................3-11

TCAS Failures ............................................................3-11Barometric Input Failures ...........................................3-11

Maintenance Codes ......................................................... 3-12

Chapter 4 Principles of Operation ....... 4-1Introduction ..........................................................................4-1Sensitivity Levels ..................................................................... 4-2

Sensitivity Level A .............................................................4-2Sensitivity Level B .............................................................4-2

Audio Inhibit, TCAS791 ........................................................4-4Audio Inhibit, GPWS .............................................................4-5TA Symbol Duration ..............................................................4-5No-Bearing TA’s ..................................................................... 4-5Ground Intruder Filtering .......................................................4-5Interference Limiting ..............................................................4-6

Chapter 5 Display Interpretation......... 5-1Introduction ..........................................................................5-1

Chapter 6 Specifications ................... 6-1

TCAS791 Pilot’s Guidevi

List of IllustrationsFigure Title Page

1-1 TCAS791 Major Components ....................................................... 1-11-2 Typical Screen on the CD605 Control Display Unit........................ 1-31-3 TCAS791 Simplified Functional Diagram ......................................1-41-4 Vertical Display Modes & Traffic Zones .......................................... 1-6

2-1 Controls & Screen Elements .......................................................... 2-12-2 Display Ranges on the CD605 ....................................................... 2-82-3 An Alternate Display w/Photocell & Off-Center Aircraft Symbol .......... 2-9

3-1 Startup Screen ............................................................................... 3-23-2 Standby Screen .............................................................................. 3-23-3 Test Screen .................................................................................... 3-33-4 TCAS Failed Screen ....................................................................... 3-43-5 Standby Screen with Maintenance Code ......................................... 3-53-6 Above Display Mode, 10 nmi Range .............................................. 3-63-7 Vertical Display Modes .................................................................. 3-83-8 Normal Display Mode, 5 nmi Range ............................................3-103-9 TCAS Failed/Barometric Input Screen ..........................................3-113-10 Maintenance Code When on the Ground but Not in Standby .......3-12

4-1 TA Zones if Your Aircraft Has a Radio Altimeter ............................. 4-34-2 TA Zones if Your Aircraft Has No Radio Altimeter, But Does

Have a Retractable Landing Gear ................................................... 4-34-3 TA Zones if Your Aircraft Has No Radio Altimeter and a Fixed

Landing Gear ................................................................................4-4

5-1 Traffic Advisory and Other Traffic ..................................................5-15-2 Off-Scale Traffic Advisory ..............................................................5-25-3 No-Bearing Traffic Advisory ........................................................... 5-25-4 No-Bearing No-Altitude Traffic Advisory ........................................ 5-25-5 Proximity Advisory ........................................................................ 5-35-6 TCAS Failed Screen ....................................................................... 5-35-7 TCAS Failed/Barometric Input Screen ............................................5-35-8 Standby Screen .............................................................................. 5-45-9 Out of Standby on the Ground ...................................................... 5-4

TCAS791 Pilot’s Guide vii

Table Title PageList of Tables

4-1 Ten Situations in Which a TA Will Occur ....................................... 4-1

6-1 TRC Specifications ........................................................................ 6-16-2 CD605 Control Display Unit Specifications ................................... 6-36-3 NY156 TCAS Directional Antenna Specifications ........................... 6-46-4 NY152 L-Band Antenna Specifications .......................................... 6-5

TCAS791 Pilot’s Guideviii

TCAS791 Pilot’s Guide 1-1

System DescriptionC h a p t e r 1

General DescriptionThe L-3 Avionics Systems TCAS791 is an airborne Trafficalert and Collision Avoidance System (TCAS I). It monitorsthe airspace around your aircraft and advises the flight crewwhere to look for nearby transponder-equipped aircraft thatmay pose a collision threat. The TCAS791 is intended for useby regional airlines and corporate and general aviationaircraft. Figure 1-1 shows the major components of theTCAS791.

The TCAS791 displays traffic information on the CD605Control Display Unit (CDU) or on a compatible EFIS orIVSI/TCAS display and generates aural announcements on

Figure 1-1. TCAS791 Major Components

CD605

TRCL-BandOmnidirectionalAntenna

DirectionalAntenna

TCAS791 Pilot’s Guide1-2

Chapter 1 – System Description

the cockpit sound system. Traffic information on the displayconsists of color-coded symbols and text. The type of informa-tion displayed depends on the type of intruder aircraft, butgenerally includes the relative range, bearing, and altitude ofintruder aircraft as well as its vertical speed direction.

Major ComponentsThe TCAS791 consists of four major components as de-scribed below.

Directional AntennaThe directional antenna transmits omnidirectional tran-sponder interrogations and is used as a directional antennafor receiving transponder replies.

L-Band Omnidirectional AntennaThe L-band omnidirectional antenna receives transponderreplies.

Transmitter Receiver Computer (TRC)The TRC is the primary unit of the TCAS791. It contains thecircuitry necessary to convert inputs into aural and visualadvisories of intruding aircraft. The TRC can track up to 35intruder aircraft simultaneously. If the TRC is tracking morethan eight intruder aircraft, to reduce clutter, it will onlydisplay the eight most threatening ones. If the TRC istracking eight or fewer intruder aircraft, it will display all theintruders. The TRC also contains Built-In Test Equipment(BITE) which can detect faults or failures and verify that theTCAS791 is operating properly.

Major Components


Chapter 1 – System Description

Control Display Unit (CDU)The CD605 is a self-contained unit that provides display andcontrol functions. The display is a high resolution CathodeRay Tube (CRT). The CRT displays data in three colors:white, cyan (blue), and amber (yellow) on a black back-ground. (See figure 1-2.)

You may choose to display TCAS information on a compat-ible EFIS or IVSI/TCAS display in lieu of, or in addition tothe CD605. The alternate displays provide display functionssimilar to the CD605, but require discrete switches mountedin the cockpit.

Major Components

Figure 1-2. Typical Screen on the CD605 Control Display Unit


Chapter 1 – System DescriptionInteraction of Major Components

Interaction of Major ComponentsFigure 1-3 shows how the major components of the TCAS791connect to each other and to other aircraft systems.

Notes on Figure 1-3:

1. You can use the TCAS791 without a radio altitude input,but when you’re flying at low altitudes, you may see morenuisance traffic alerts (from aircraft on the ground thathave their transponders on).

Figure 1-3. TCAS791 Simplified Functional Diagram

AircraftAudio

SystemDiagnostic Commandsand Status (RS-232)

5

Display (Arinc 429)6Alternate Display

(Compatible EFISor IVSI)

Discrete Switchesif Using an

Alternate Display

Avionics Dimmer

DiagnosticEquipment

Landing GearPosition Switch

AircraftSuppression Bus

Aircraft CompassSystem

Radio Altitude1,2

Barometric Altitude2

Heading2

Audio Inhibit4

TRC

Aural TA's

TX/RX Inhibit

LandingGear Position

Weight On Wheels

28 V dc

DirectionalAntenna

TCAS791

Intruder Aircraft

Radio Altimeter

EncodingAltimeter

3

TransponderInterrogations

TransponderInterrogations

RepliesTransponder

RepliesTransponder

GPWS

Squat Switch

Aircraft Power

Control

Control

CD605 Display

AvionicsDimming5

Transponder

Replies

Intruder Aircraft

Transponder RepliesL-Band

OmnidirectionalAntenna


Chapter 1 – System Description Functional Description

2. An air data computer, LNAV system, GPS, or other Arinc429 output device may replace individual analog sensorsfor supplying radio and barometric altitude, and heading.

3. The TCAS791 may be installed on an aircraft with a fixedlanding gear. The only operational difference occurs whenyou don’t have a radio altitude input. In that case, theTCAS791 defaults to using the highest TA sensitivity levelregardless of your phase of flight.

4. This audio inhibit input is only required if you have aGround Proximity Warning System (GPWS) installed.

5. The avionics dimming input and the diagnostic RS-232input/output are not required for normal TCAS791operation.

6. The Arinc 429 display output is only used if you connectthe TRC to an alternate display.

Functional DescriptionThe TCAS791 is an active system that operates as an air-to-air or ground-to-air interrogation device. The TCAS791interrogates transponders in the surrounding airspace similarto ground-based radars. When replies to these interrogationsare received, the responding aircraft's range, bearing, relativealtitude, and closure rate are computed to plot trafficlocation and to predict collision threats.

Figure 1-4 shows the TCAS791 traffic zones around youraircraft and the corresponding traffic symbols that appear onthe display when intruding aircraft enter one of those zones.

The solid amber circle is the visual part of the visual andaural Traffic Advisory (TA) that the TCAS791 generates whenit predicts that an intruder aircraft may present a collisionthreat. The aural part of the TA, “traffic, traffic,” is annunci-ated over a cockpit speaker or headset. A solid white dia-mond on the CD605 is called a proximity advisory and anopen white diamond represents other traffic. (Symbol colormay vary on alternate displays.)


Chapter 1 – System DescriptionTraffic Zones

The TCAS791 uses either sensitivity level A (SLA) or sensitiv-ity level B (SLB) to determine when to display a TA. Ingeneral, SLB is used during the cruise phase and SLA is usedduring takeoff and landing. Sensitivity levels, interferencelimiting, and other factors affecting the display of trafficsymbols are discussed in detail in chapter 3, Principles ofOperation. Look up, look down, and normal vertical displaymodes are described in chapter 2, Operating Instructions.

Figure 1-4. Vertical Display Modes & Traffic Zones

0.2 nmi

0.55 nmi

4 nmi

Max. Display Range +2700 ft

–2700 ft

+9000 ft

Intruder Aircraft

–9000 ft

*15 seconds for non-altitude reporting intruder aircraft

Not To Scale

+1200 ft

–1200 ft

+800 ft

–800 ft

+600 ft

–600 ft

Max. Display Range

This area or 30 secondsSensitivity Level B

This area or 20 seconds

Sensitivity Level A

Look

Dow

n (B

LW)Lo

ok U

p (A

BV)

Nor

mal

(N

RM

)

0 ft

**20 seconds for non-altitude reporting intruder aircraft

*

**


Chapter 1 – System Description Features

Features• Tracks up to 35 intruder aircraft (displays the 8 most

threatening aircraft of those tracked)

• Monitors a horizontal range of 27 nmi (nominal), 35 nmi(max) and a relative altitude range of ±10,000 ft

• Displays data in several ranges on all displays including 5,10, and 20 nmi on the CD605

• Does not require a mode S transponder

• Look up/look down vertical display modes simplifyintruder aircraft identification (look up/look down is notavailable on some alternate displays)

• Generates a visual and aural advisory of intruding aircrafton a collision course with your aircraft

• Automatic and pilot-initiated self test functions

• Three-color display: amber, cyan, and white on a blackbackground

• Ground target filtering, sensitivity levels, and audio inhibitfunctions to limit nuisance TA’s

• Transmits interrogations from the ground as well as fromthe air


Controls &Indicators

C h a p t e r 2

IntroductionThis chapter describes the TCAS791 controls and indicatorsincluding the controls, indicators, and symbols on thedisplay, discrete controls and indicators, and aural an-nouncements.

Controls, Indicators, & SymbolsFigure 2-1 and the following paragraphs describe theTCAS791 controls, indicators, and symbols.

Figure 2-1. Controls & Screen Elements

Display RangeIndicator

Off-Scale TA

Data Tag

Range Rings

Own Aircraft

No BearingTA

TrafficAdvisory (TA)

ProximityAdvisory (PA)

No BearingNo Altitude TA

Vertical TrendArrow

Power/Brightness

Control Knob

Other Traffic(OT)

TestButton

RangeButton

VerticalDisplay ModeIndicator


Chapter 2 – Controls & IndicatorsOn-Screen Indicators

Some alternate displays do not display traffic symbols, rangerings, or the own aircraft symbol unless an intruder aircraft hasbeen detected within the selected display range.

The color of traffic symbols and the color, position, and formatof status messages, indicators, and other items on the displaymay vary on alternate displays.

Refer to chapter 4, Principles of Operation, for a description ofother factors that may affect the display of traffic symbols.

Traffic Advisory (TA) A TA consists of a visualsymbol on-screen and an aural “traffic, traffic”message over a cockpit speaker or headset. When anintruder aircraft that meets the TA criteria describedin chapter 4 is within the displayed range (inside oroutside of the selected vertical display mode), thecorresponding visual symbol is this solid amber circlelocated at a position on the screen that indicates therelative bearing and range of the intruder aircraft.

In general, a TA occurs when an intruder aircraft isdetected within 15–30 seconds of a possible collision,or within 0.2–0.55 nmi and ±600 ft to ±800 ft of youraircraft.

Off-Scale TA When an intruder aircraft that meetsthe TA criteria described in chapter 3 is beyond thedisplayed range, the corresponding TA symbol is thissolid amber semicircle located at a position along theouter range ring that indicates the relative bearing ofthe intruder aircraft. Range is the only factor thatdetermines whether a TA is represented by a circle or asemicircle. For example, if a TA is within the displayrange but outside of the selected vertical display mode,it’s still represented by a circle instead of a semicircle.

Proximity Advisory (PA) PAs indicate therelative location of any traffic not generating a trafficadvisory but which is within 4 nautical miles (nmi)

NOTE

NOTE

NOTE


Chapter 2 – Controls & Indicators On-Screen Indicators

and ±1,200 ft of your aircraft. Non-altitude reportingaircraft are considered to be at the same altitude asyour aircraft.

Other Traffic This symbol represents traffic withinthe selected display range and vertical display modethat is not proximate traffic nor traffic generating aTA. Non-altitude-reporting intruder aircraft areconsidered to be at the same altitude as your aircraft.

On some alternate displays, other traffic symbolsdisappear when a TA occurs and reappear (if still inrange) once the TA goes away. Some alternate displayscan also be strapped to filter out all other traffic.

Vertical Trend Arrow A vertical trend arrowindicates that the intruding aircraft is descending(down arrow) or ascending (up arrow) at a rate greaterthan 500 fpm. No arrow is shown for non-altitude-reporting aircraft.

Data Tag These two digits indicate, inhundreds of feet, the relative altitude of theintruder aircraft. A positive data tag is displayedabove the traffic symbol to emphasize that theintruder aircraft is above your aircraft. Similarly,a negative data tag is displayed below the trafficsymbol. If the intruder is at the same altitude asyour aircraft, 00 is displayed above the trafficsymbol if the intruder closed from above, or belowthe symbol if the intruder closed from below.

The data tag for a vertically out of range TAremains at the maximum or minimum altitudenumber for the current vertical display modeuntil the intruder aircraft comes within thevertical limits of the selected vertical displaymode. The TCAS791 only displays data tags foraltitude-reporting aircraft.


Chapter 2 – Controls & Indicators

No-Bearing No-Altitude TA Ifbearing and altitude are not available foran intruder aircraft that meets the TAcriteria described in chapter 4, the TAtakes the form of this amber line of textconsisting of the letters TA and theintruder aircraft’s range.

No-Bearing TA If bearingis not available for an intruderaircraft that meets the TAcriteria described in chapter 4,the TA takes the form of thisamber line of text beginningwith the letters TA andincluding the intruderaircraft’s range, a data tag,and a vertical trend arrow.

Own Aircraft This symbol represents your aircraft.

Display Range Indicator This indicatordisplays the numerical value of the currentlyselected display range. Figure 2-2 lists theCD605 display ranges. (Display ranges onalternate displays may vary.)

Vertical Display Mode Indicator On theCD605, this indicator displays the currentlyselected vertical display mode: ABV (above, orlook up), BLW (below, or look down), or NRM(normal).

Some alternate displays do not display the NRMindicator. Other alternate displays do not displayany vertical display mode indicators because theydo not support any vertical display modes otherthan normal.

On-Screen Indicators



In the above display mode, traffic detected within+9,000 ft and –2,700 ft of your aircraft is dis-played. In the below display mode, traffic within+2,700 ft and –9,000 ft of your aircraft is displayed.In the normal display mode, traffic detected within±2,700 ft of your aircraft is displayed.

Power/Brightness Control Knob Rotatingthe DIM/OFF knob on the CD605 clockwise turns onthe CD605 and the TRC and increases the brightnessof the display. If you’re using an alternate display,you’ll use a discrete TCAS ON/OFF switch to turn onthe TRC.

Some alternate displays have a built-in photocell thatautomatically controls the display’s brightness. (Seefigure 2-3.) Other alternate displays use the cockpitdimming input to control display brightness. Otheralternate displays have no display dimming controls.

Range Button The range button (labeled RNG)is on the front of the CD605. If you’re using analternate display, display range selection is usuallycontrolled from a discrete button in the cockpit. Ifyou are using the CD605 and an alternate display,you can use both range buttons.

The avionics dimming input from your aircraftcontrols the brightness of the light inside the rangebutton on the CD605.

Pressing the range button when in standby switchesthe TCAS791 out of standby and into the 10 nmirange and the above vertical display mode. (Alternatedisplays may switch into some other range andvertical display mode.)

Pressing the range button repeatedly when not instandby toggles the display through the availabledisplay ranges. Figure 2-2 lists the CD605 display

Controls



ranges. (Display ranges on alternate displays mayvary.) The selected range is indicated on the screen.

Pressing and holding the range button when on theground and not in standby changes the range andthen switches the TCAS791 into standby. Pressingand holding the range button in flight has no effectother than changing the range.

Test Button The test button is on the front ofthe CD605. If you’re using an alternate display, adiscrete button in the cockpit serves as the testbutton. If you are using the CD605 with an alternatedisplay, you can use both test buttons.

The avionics dimming input from your aircraftcontrols the brightness of the light inside the testbutton on the CD605.

Pressing the test button when in standby starts aTCAS791 self test.

Pressing the test button repeatedly when not instandby toggles the vertical display mode in thefollowing order: above, normal, below, normal,above, etc. (Repeatedly pressing the test button withan alternate display that does not support the aboveand below display modes has no effect.)

Pressing and holding the test button when in standbywill run the test, and if the test passes, will hold thetest screen on the CD605 or the final test screen onan alternate display. When you release the button,the display goes back to its standby screen. Holdingthe test button in does not hold the test screen onthe display if the test fails. In this case, the CD605goes to its TCAS FAILED screen and the alternatedisplay goes to its TCAS FAIL screen or to its standbyscreen, depending on the display model.

TA ONLY Indicator When theTCAS791 is on and not displaying a failureand not in standby, some of the alternate

TA ONLY

Controls



displays will display the TA ONLY indicatoron the screen. This indicator means thatthe display is either connected to a TCAS Isystem or to a TCAS II system in TA ONLYmode. In both cases, the implication is thatno resolution advisories will be issued. Onsome alternate displays, when an active TAis detected, the background color of theTA ONLY indicator changes from whiteto amber.

TCAS FAIL Indicator The CD605displays the message TCAS FAILED whenthe TCAS791 detects a failure and after anoperator-initiated self test failure.

On some alternate displays, the messageTCAS FAIL is displayed when theTCAS791 is not powered up. Thesealternate displays continue to displayTCAS FAIL for several seconds after theTCAS791 is turned on. The TCAS FAILmessage may also appear on the alternatedisplays if there’s a TCAS failure, or if theTCAS791 fails a self test. It is also possiblefor an alternate display to display TCASOFF instead of TCAS FAIL after a self testfailure on the ground.

TCAS OFF Indicator The TCAS OFFindicator is displayed on some alternatedisplays. It indicates that the TCAS791 is instandby. It does not mean that theTCAS791 has been turned off.

Self Test Indicator An indicator such as thismay be displayed on an alternate display toindicate that the TCAS791 operator-initiated selftest is in progress.

TCAS FAIL

TEST

TCAS OFF




OFF SCALE Indicator Some alternate displays displaythe words OFF SCALE when an out of range TA occurs. Thisindicator is in addition to an off-scale TA symbol (ambersemicircle).

Range Rings The range rings indicate distance fromyour aircraft. Figure 2-2 lists the distances of the range ringson the CD605. On the CD605, the range rings are centeredon the own aircraft symbol in the middle of the screen.

On some alternate displays, the aircraft symbol is located atthe lower center of the screen which causes clipping of theTCAS display range area. (See figure 2-3.) On these displays,the 12:00 position on or near the outer range ring representsthe selected range, but as you move around to the 6:00position on the outer range ring, the range displayed de-creases to 60 percent or lower of the selected range depend-ing on the display.


*When used withan alternatedisplay, theCD605 takes onthe display rangesof the alternatedisplay.

Available Display Ranges* Range Distance From OwnOn The Ground In The Air Rings Aircraft to Range Ring

5 nmi 5 nmi inner 2 nmiouter 5 nmi

10 nmi 10 nmi inner 2 nmimiddle 5 nmiouter 10 nmi

20 nmi inner 5 nmimiddle 10 nmiouter 20 nmi

Figure 2-2. Display Ranges on the CD605



Audio Alert Adjustment Screw This 1-turn potenti-ometer inside the data card access door on front of the TRCadjusts the volume of aural messages. If the volume levelpreset at the factory is not appropriate for your installation,use a small screwdriver to turn the screw clockwise toincrease the volume or counterclockwise to decrease thevolume. Use extreme caution if you adjust this screw.Applying too much pressure will break the plastic adjust-ment screw housing off of the circuit board.

Auto/Man Switch This discrete toggle switch is onlyrequired for some alternate displays. This switch allows youto select TCAS auto mode or TCAS manual mode.

TCAS auto mode allows a non-TCAS display page to beautomatically interrupted when a TA occurs. TCAS informa-tion will pop up on the display and remain displayed untilseveral seconds after the traffic is no longer a threat. Thedisplay will then revert to the function that was selectedbefore the TA occurred.

TCAS manual mode prevents the display from being inter-rupted by TCAS information. When a TA occurs, the auralmessage is announced, but the visual TCAS information isnot displayed (unless TCAS was already selected on the display).

Other Controls

6NM

Photocell

6 nmi

2.5 nmi

3.7 nmi2 nmi

Sample OnlyYour alternate

display may differ.

Figure 2-3.An Alternate Display w/Photocell & Off-CenterAircraft Symbol


Chapter 2 – Controls & IndicatorsAural Announcements

Aural Announcements“Traffic Traffic” This aural component of a trafficadvisory is announced once over the cockpit speakers orheadset when a TA aircraft is first detected.

“TCAS Test Passed” This message is announced overthe cockpit speakers or headset after the TCAS791 has passedan operator-initiated self test.

“TCAS Test Failed” This message is announced over thecockpit speakers or headset after the TCAS791 has failed anoperator-initiated self test.


OperatingInstructions

C h a p t e r 3

IntroductionThis chapter lists the TCAS791 operating instructions anddescribes its fault modes.


Optimum TCAS791 performance is realized when intruderaircraft are reporting their altitude (via a mode C or otheraltitude reporting transponder).

Federal aviation regulations require that, if installed, TCASequipment be turned on during all flight operations. As such,the TCAS791 may be turned off only when it is inoperable orwhen, in the opinion of the pilot-in-command, continuedoperation would be more appropriately assured with theTCAS791 turned off.

The TCAS791 must be turned off if ATC advises the flight crewto disable transponder altitude reporting.

Turn On the TCAS7911. If you’re using a display other than the CD605, turn on that

alternate display system and set it to display TCAS information.

WARNING

CAUTION

NOTE

NOTE


Chapter 3 – Operating InstructionsTurn On the TCAS791

2. If you’re using an alternate display that requires a discreteTCAS Auto/Man switch, make sure the switch is set to thedesired mode.

3. Rotate the DIM/OFF knob on the CD605 clockwise about 180degrees. If you’re using an alternate display, move thediscrete TCAS ON/OFF switch to the ON position.

The TCAS791 begins its power-up and initialization routine.During this power-up and initialization, the CD605 displaysthe startup screen as shown in figure 3-1. The startupscreen lists the firmware version numbers. After about 35seconds, the TCAS791 goes into standby and the CD605displays the standby screen as shown in figure 3-2.

Some alternate displays do not display the startup andstandby screens as shown; instead, they display themessage TCAS FAIL until the TCAS791 completes itspower-up and initialization routine, then they display adifferent standby screen, such as TCAS OFF.

Run the Operator-Initiated Self TestYou should run the operator-initiated self test before the firstflight of the day or as specified in the specific Aircraft OperatingManual (AOM). The self test function is inhibited unless theaircraft is on the ground and the TCAS791 is in standby.

Figure 3-1. Startup Screen Figure 3-2. Standby Screen


Chapter 3 – Operating Instructions Run the Self Test

1. Set the pilot’s barometric altimeter to 29.92 and make noteof the indicated pressure altitude.

2. With the TCAS791 in standby, press the test button in one ofthe following two ways:

a. Press and release the test button.

Pressing and releasing the test button allows the displayto automatically revert to the standby screen afterbriefly displaying the test screen and any status screens.

b.Press and hold the test button.

Pressing and holding the test button holds the resultingtest screen on the CD605 or the final status screen onan alternate display until you release the test button.(This holding feature does not work if the test fails.)

The TCAS791 begins its self test and the CD605 displays atest screen similar to that shown in figure 3-3. An alter-nate display may display a different test screen.

Upon successful completion of the self test, you shouldhear the “TCAS Test Passed” message and the CD605should revert to the standby screen. An alternate displaymay display one or more status screens before reverting toits standby screen (TCAS OFF).

Upon unsuccessful completion of the self test, you shouldhear the “TCAS Test Failed” message and the CD605

Figure 3-3. Test Screen


Chapter 3 – Operating Instructions

should display the TCAS Failed screen as shown in figure3-4. The TCAS791 reverts to standby (so that you canpress the test button again and run the test again) but theTCAS Failed screen remains on the display. An alternatedisplay may display a TCAS FAIL message instead of aTCAS Failed screen, or it may revert to its standby screen(TCAS OFF).

3. If the altitude displayed at the bottom of the test screen onthe CD605 is not within ±250 ft of the altitude indicated onthe barometric altimeter, turn off the TCAS791 and scheduleit for corrective maintenance as soon as possible.

4. If you hear the “TCAS Test Failed” message or see a TCAS Failedscreen or a TCAS FAIL message, turn off the TCAS791 andschedule it for corrective maintenance as soon as possible.

5. If you hear the “TCAS Test Passed” message without seeing thetest screen on the CD605, turn off the TCAS791 and schedulethe CD605 for corrective maintenance as soon as possible.

6. If you hear the “TCAS Test Passed” message but a mainte-nance code appears at the bottom of the standby screen onthe CD605 (figure 3-5), continue to use the TCAS791, butschedule it for corrective maintenance as soon as possible.

Refer to the section on maintenance codes later in thischapter for more information.

Figure 3-4. TCAS Failed Screen

Run the Self Test



7. When you’re done with the self test, reset the barometricaltimeter to the current barometric setting.

Switch Out of StandbyYou must manually switch out of standby using the follow-ing procedure if you want the TCAS791 to display trafficinformation while you’re still on the ground. If you do notmanually switch out of standby, the TCAS791 will automati-cally switch out of standby 8 to 10 seconds after takeoff andinto the above display mode and 10 nmi range on the CD605(display mode and range may vary on alternate displays). Theability to switch out of standby on the ground in conjunctionwith the above display mode is especially helpful when you’regetting ready to take off from an airstrip that doesn’t have anATC tower to tell you what traffic is above and around you.

1. Press the range button.

The TCAS791 switches out of standby and into the abovedisplay mode and 10 nmi range. (See figure 3-6.) Analternate display may switch into some other verticaldisplay mode and range. The TCAS OFF message (dis-played on some alternate displays) goes away and may bereplaced by the TA ONLY message.

Figure 3-5. Standby Screen With Maintenance Code

Switch Out of Standby



Switch Into StandbyUse this step if you need to go back into standby whileyou’re still on the ground. (The TCAS791 does not go intostandby while airborne, but does automatically go intostandby 24 seconds after landing.)

1. Press and hold the range button.

The range changes, the TCAS791 goes into standby, andthe display switches back to its standby screen (figure 3-2for the CD605). The TA ONLY message (displayed onsome alternate displays) changes to TCAS OFF.

Select the RangeYou can select from the available display ranges when youraircraft is on the ground and the TCAS791 is not in standby,or when your aircraft is in the air. The shortest range shouldtypically be used during departure, climbout, and descent toreduce traffic clutter.

1. Press the range button repeatedly until the desired range isdisplayed.

With each press of the range button, the screen changes todisplay the traffic detected within the next availabledisplay range. The range indicator also changes to displaythe numerical value of the selected range.

Figure 3-6. Above Display Mode, 10 nmi Range

Switch Into Standby



The sequence of ranges is from longest to shortest thenback up to the longest. Figure 2-2 lists the display ranges onthe CD605. Display ranges on alternate displays may vary.

Intruder aircraft within the TCAS791 tracking range butoutside of the current display range continue to betracked even though they’re not displayed in the currentdisplay range.

The TCAS791 continues to track up to 35 intruder aircraftwithin a maximum horizontal radius of 35 nmi regardlessof the display range selected.

Select the Vertical Display ModeYou can select a vertical display mode when your aircraft ison the ground and the TCAS791 is not in standby, or whenyour aircraft is in the air. The above mode typically shouldbe set just prior to takeoff to look for traffic during depar-ture and climbout. The normal mode is recommended forthe cruise phase. The below mode should typically be setprior to initiating a descent from cruise altitude.

1. Press the test button repeatedly until the desired verticaldisplay mode is displayed.

With each press of the test button, the TCAS791 switchesinto the next vertical display mode and displays the trafficdetected within the corresponding vertical display range.(See figure 3-7.)

The vertical display mode indicator also changes todisplay the abbreviated name of the selected verticaldisplay mode (ABV, NRM, or BLW).

Up to 35 intruder aircraft within 10,000 ft above or belowyour aircraft continue to be tracked regardless of thevertical display mode selected.

Select the Vertical Display Mode



Observe the DisplayMonitor the activity of any traffic displayed. Keep in mindthe following points when watching traffic on the display:

• Traffic Prioritizing – The TCAS791 can track up to 35intruder aircraft simultaneously, but to reduce clutter, itdisplays only the 8 most threatening aircraft of thosetracked.

• Traffic symbols may occasionally disappear and reap-pear due to traffic prioritizing (see above), interferencelimiting, antenna shielding, or reception of low powertransponders (see chapter 4).

• Ground Intruder Filtering – If your aircraft has acompatible radio altimeter connected to the TCAS791,TAs, PAs, and other traffic symbols are not issued fortraffic detected under 380 ft AGL when your aircraft isbelow 1,700 ft AGL.

+2700 ft

–2700 ft

+9000 ft

Intruder Aircraft

–9000 ft

Bel

owD

ispl

ay M

ode

(Loo

k D

own)

Abo

veD

ispl

ay M

ode

(Loo

k U

p)

Nor

mal

Dis

pl. M

ode

0 ft

Max. Display Range

Max. Display Range

Own Aircraft

Figure 3-7. Vertical Display Modes

Observe the Display



• On some alternate displays, other traffic symbolsdisappear when a TA occurs and reappear (if still inrange) once the TA goes away.

• Some alternate displays can be strapped to filter outother traffic.

• Refer to chapter 4 for a description of TA criteria andother factors that affect the display of traffic symbols.

Respond to Traffic Advisories

Do not attempt evasive maneuvers based solely on trafficinformation shown on the TCAS791 display. Informationshown on the display is provided to the aircrew only as an aidin visually acquiring traffic which may impose a collision threat. Itis not a replacement for ATC and the See & Avoid concept.


When the TCAS791 issues a TA, look outside for the intruderaircraft. If you can’t see it, you may want to contact ATC foradditional traffic information. When you spot an intruderaircraft, use normal right-of-way procedures to maintainseparation. Begin evasive maneuvers only in response tovisual contact with the intruder aircraft.

Turn On the TCAS791 While in FlightThis section describes a scenario in which your TCAS791 wasnot turned on prior to takeoff, but must now be turned onduring flight. Turning on the TCAS791 during flight followsthe same turn-on procedures listed previously, except thatinstead of going into standby and displaying the standbyscreen after the startup screen, the TCAS791 goes directlyinto the 5 nmi range, normal display mode after the startupscreen. (See figure 3-8.) An alternate display may switch intosome other vertical display mode and range.

WARNING

WARNING

Respond to Traffic Advisories



The TCAS FAIL message displayed on some alternate displaysduring startup may change to TCAS OFF momentarily beforechanging to TA ONLY.

Post-Flight InstructionsThe TCAS791 automatically switches into standby onceyou’ve landed and have been on the ground for at least 24seconds. (This delay allows the TCAS791 to remain out ofstandby during a touch-and-go maneuver.) Once on theground in standby, you can manually switch back out ofstandby to monitor traffic above and around you, or you canstay in standby. In either case, you can turn off the TCAS791as described below. You may want to leave the TCAS791 onafter landing until you have had a chance to see if there’s amaintenance code on the CD605. A maintenance code onlyshows up when you’re on the ground, and only on theCD605. (Refer to the section on maintenance codes later inthis chapter.)

Turn Off the TCAS7911. Rotate the DIM/OFF knob on the CD605 counterclockwise

until the switch turns off. If you’re using an alternate display,move the discrete TCAS ON/OFF switch to the OFF position.

2. If you’re using an alternate display, turn it off.

Figure 3-8. Normal Display Mode, 5 nmi Range

Post-Flight Instructions



Error MessagesThe TCAS791 displays two types of error messages: TCASFailed screens, and maintenance codes. (Some alternatedisplays do not display maintenance codes and display aTCAS FAIL message instead of a TCAS Failed screen.)

TCAS Failed ScreensA TCAS Failed screen can show up at any time on theground or in the air. There is a TCAS Failed screen for TCASfailures and a TCAS Failed screen for barometric input failures.

TCAS Failures – The TCAS791 displays the TCAS Failedscreen (figure 3-4) and aurally announces “TCAS test failed”when the TCAS791 fails the operator-initiated self test. Anyother time the TCAS791 fails, the TCAS791 displays the TCASFailed screen but does not aurally announce the failure. TheTCAS791 attempts to recover, but if the TCAS Failed messageremains on the screen for more than 5 minutes, turn off theTCAS791 and schedule it for maintenance as soon as possible.

Barometric Input Failures – The TCAS791 displays theTCAS Failed/Barometric Input screen (figure 3-9) and stopstransmitting interrogations when it fails to detect barometricaltitude (e.g. input from an encoding altimeter). TheTCAS791 can not operate without a barometric altitudeinput. Most barometric input failures are likely due to the

Figure 3-9. TCAS Failed/Barometric Input Screen

Error Messages



failure of equipment external to the TCAS791. If the TCASFailed/Barometric Input screen appears, do not turn off theTCAS791. When the barometric altitude input is restored,the TCAS791 automatically returns to normal operation.

Maintenance CodesA maintenance code can only show up when your aircraft ison the ground. Figure 3-5 shows a maintenance code on thestandby screen. Figure 3-10 shows a maintenance code withthe aircraft on the ground but not in standby. The TCAS791can be used when a maintenance code is displayed, butshould be scheduled for maintenance as soon as possible.

Figure 3-10. Maintenance Code When on the Ground but Notin Standby

Error Messages


Principles ofOperation

C h a p t e r 4

IntroductionThis chapter describes Traffic Advisory (TA) criteria and otherfactors that affect the display of traffic symbols. Table 4-1 summa-rizes the criteria necessary for the TCAS791 to display a TA.

Sensitivity Level A Sensitivity Level B

The TCAS791 Will Issue a Traffic Advisory…

No.If Your

Aircraft…

And YourAircraft’s

Altitude Is…

And YourLanding

Gear Is…And An Intruder

Aircraft Is Detected…

1 has a radioaltimeter*

below 2000 ftAGL

within a 0.2 nmi horizontalradius and a ±600 ft relativealtitude

2 within 15–20 sec. of CPA**

3 above 2000 ftAGL

within a 0.55 nmihorizontal radius and a±800 ft relative altitude


5 does nothave a radioaltimeter*

down within a 0.2 nmi horizontalradius and a ±600 ft relativealtitude


7 up within a 0.55 nmihorizontal radius and a±800 ft relative altitude


9 fixed within a 0.55 nmihorizontal radius and a±800 ft relative altitude


Table 4-1. Ten Situations in Which a TA Will Occur

* Having a radio altimeter means having a compatible radio altimeter wired to theTCAS791 and providing valid altitude information.

** CPA means Closest Point of Approach.


Chapter 4 – Principles of OperationSensitivity Levels

Sensitivity LevelsThe TCAS791 uses one of two sensitivity levels, A or B, todetermine when to display a TA. Having two sensitivitylevels allows the TCAS791 to reduce the number of nuisanceTA’s during takeoff and landing (sensitivity level A), and tomaximize the detection of TA’s during the cruise phase offlight (sensitivity level B).

Sensitivity Level ASensitivity level A consists of two criteria for displaying a TA:

1. The intruder aircraft enters into a cylinder of airspacesurrounding your aircraft defined by a 0.2 nmihorizontal radius and a height of ±600 ft from youraircraft. (See figures 4-1 and 4-2.)

OR…2. The intruder aircraft approaches your aircraft on a

course that will intercept your aircraft within 15 or20 seconds (within 15 seconds for a non-altitudereporting intruder aircraft; within 20 seconds for analtitude reporting intruder aircraft).

The TCAS791 uses sensitivity level A in the following situations(corresponds to numbers 1, 2, 5, and 6 in table 4-1):

1. Your aircraft has a radio altimeter and is below 2,000ft AGL.

2. Your aircraft has no radio altimeter but its retractablelanding gear is down.

Sensitivity Level BSensitivity level B consists of two criteria for displaying a TA:

1. The intruder aircraft enters into a cylinder of airspacesurrounding your aircraft defined by a 0.55 nmihorizontal radius and a height of ±800 ft from youraircraft. (See figures 4-1 through 4-3.)

OR…2. The intruder aircraft approaches your aircraft on a

course that will intercept your aircraft within 20 or 30seconds (within 20 seconds for a non-altitude report-


Chapter 4 – Principles of Operation

0.2 nmi +600 ft

–600 ftThis area or 20 seconds*

0.55 nmi +800 ft


*

**15 seconds for non-altitude reporting intruder aircraft*20 seconds for non-altitude reporting intruder aircraft Not to scale

Intruder aircraft

GL

If ownaircraftis below1,700 ftAGL

If ownaircraftis below400 ftAGL

2,000feet

Groundintruders

below380 ft

AGL arefiltered

outTA zone whenown aircraft isbelow 2,000 ft

(sensitivity level A)

TA zone whenown aircraft isabove 2,000 ft

(sensitivity level B)

TCAS791 audiois inhibited

Figure 4-1. TA Zones If Your Aircraft Has a Radio Altimeter

Figure 4-2. TA Zones If Your Aircraft Has No Radio Altimeter,But Does Have a Retractable Landing Gear

0.2 nmi +600 ft


0.55 nmi +800 ft


*

**15 seconds for non-altitude reporting intruder aircraft*20 seconds for non-altitude reporting intruder aircraft Not to scale

Intruder aircraft

GL

TA zonewhen landing gear is up

(sensitivity level B)

TA zonewhen landing gear is down

(sensitivity level A)

TCAS791 audioinhibited when landing

gear is down

TA Zones



ing intruder aircraft; within 30 seconds for an altitudereporting intruder aircraft).

The TCAS791 uses sensitivity level B in the following situations(corresponds to numbers 3, 4, 7, 8, 9, and 10 in table 4-1):

1. Your aircraft has a radio altimeter and is above 2,000ft AGL.

2. Your aircraft has no radio altimeter but its retractablelanding gear is up.

3. Your aircraft has no radio altimeter and a fixedlanding gear.

Audio Inhibit, TCAS791This audio inhibit feature prevents the aural part of TA’s,“traffic, traffic,” from being announced during takeoff andlanding in order to minimize pilot distraction. The corre-sponding TA symbols are still displayed.

The TCAS791 uses this audio inhibit feature in the followingsituations:

1. Your aircraft has a radio altimeter and you’re below400 ft AGL. (See figure 4-1.)

2. Your aircraft has no radio altimeter but its retractablelanding gear is down. (See figure 4-2.) (Audio is notinhibited if you have fixed landing gear and no radioaltimeter.)

Figure 4-3. TA Zones If Your Aircraft Has No RadioAltimeter and a Fixed Landing Gear

0.55 nmi +800 ft


*20 seconds for non-altitude reporting intruder aircraft Not to scale

Intruder aircraft

GL

TA zone(sensitivity level B)

Audio Inhibit



Audio Inhibit, GPWSIf your aircraft has a Ground Proximity Warning System(GPWS) interfaced with the TCAS791 and a GPWS alarm occurs,the TCAS791 senses the alarm and delays the aural “traffic,traffic” component of any TA’s issued until the alarm clears.

TA Symbol DurationA TA symbol remains on the screen for at least 8 seconds,even if the intruder aircraft no longer meets the TA criteria,as long as the TCAS791 continues to track the aircraft.

No-Bearing TA’sIntruder aircraft detected only with the omnidirectionalantenna are not displayed unless they become TA’s. Theomnidirectional antenna does not detect the bearing ofintruder aircraft. The TCAS791 tracks the intruder, butwithout bearing, it can’t display a traffic symbol. If theintruder aircraft eventually meets the TA criteria, the no-bearing TA message provides a vehicle for display of theintruder aircraft.

Ground Intruder FilteringGround intruder filtering reduces the clutter of visualsymbols and aural announcements that would otherwise begenerated for intruder aircraft typically present on or nearthe ground near airports.

For intruder aircraft determined to be below 380 ft AGL,ground intruder filtering prevents the display of all trafficsymbols (TA, PA, & OT) and suppresses the “Traffic, Traffic”aural announcement. (See figure 4-1.)

The TCAS791 uses ground intruder filtering only if youraircraft has a radio altimeter connected to the TCAS791 andyou’re below 1,700 ft AGL.

Audio Inhibit



Interference LimitingTo assure that all interference effects from active TCAS Iequipment are kept to a minimum, the FAA requires TCASequipment to “interference limit,” i.e. reduce its transmitpower, when it is operating in congested airspace. Thislimiting function is based on the number of TCAS interroga-tors detected via mode S broadcast reception and the replyrate of your transponder. Interference limiting reduces theeffective surveillance range of the TCAS equipment and isindependent of the display range selected; therefore, select-ing a display range of 20 nmi does not guarantee a 20 nmisurveillance range when operating in high density areas.

Interference Limiting


DisplayInterpretation

C h a p t e r 5

IntroductionThis chapter explains the meaning of several sample screenson a CD605. The corresponding screens on alternate displaysmay vary.

Figure 5-1. Traffic Advisory and Other Traffic

Traffic AdvisoryIntruder aircraft at1 o'clock, 0.5 nmi away,300 ft above you in levelflight. Immediate threat.

Other TrafficIntruder aircraft at7 o'clock, 4.8 nmi away,6,300 ft above you inlevel flight. No immediatethreat.


Chapter 5 – Display InterpretationSpecial Traffic Advisories

Figure 5-2. Off-Scale Traffic Advisory

Figure 5-3. No-Bearing Traffic Advisory

Figure 5-4. No-Bearing No-Altitude Traffic Advisory

Off-Scale TAIntruder aircraft at11 o'clock, more than5 nmi away, 300 ft aboveyou, descending at a rategreater than 500 fpm.Closest point of approachwithin 20 to 30 seconds.

No-Bearing TAIntruder aircraft 1.1 nmiaway, 1,000 ft below you,climbing at a rate greaterthan 500 fpm.

No-BearingNo-Altitude TAIntruder aircraft 0.7 nmiaway, no bearing oraltitude available.


Chapter 5 – Display Interpretation

Figure 5-5. Proximity Advisory

Figure 5-6. TCAS Failed Screen

Figure 5-7. TCAS Failed/Barometric Input Screen

PA & Failed Screens

Proximity AdvisoryIntruder aircraft at10 o'clock, 4 nmi away,200 ft above you,descending at a rategreater than 500 fpm.No immediate threat.

This message indicatesthat the TCAS791 detectsa failure. It also appears ifthe TCAS791 fails theoperator-initiated self test.If this message remainson the screen for morethan 5 minutes, turn offthe TCAS791.

This message indicatesthat the TCAS791 hasfailed to detect barometricaltitude. If the barometricinput is restored, theTCAS791 will return tonormal operation.


Chapter 5 – Display Interpretation

Figure 5-8. Standby Screen

Figure 5-9. Out of Standby on the Ground

In & Out of Standby

This message is onlydisplayed when youraircraft is on the ground.When in standby, theTCAS791 does nottransmit interrogations ortrack intruder aircraft.

Instructions for switchingout of standby andbeginning TCASprocessing (press theRNG button)

Instructions for switchinginto standby and stoppingTCAS processing (pressand hold the RNG button).This message onlyappears when youraircraft is on the ground.


SpecificationsC h a p t e r 6

Table 6-1. TRC Specifications*

*Specifications subject to change without notice.(Continues on next page)

Part Number Definition:805-10001-004 – model TRC791805-10001-024 – model TRC791A805-10001-025 – model TRC791A Rotorcraft

Size:7.62 in (19.35 cm) high6.39 in (16.23 cm) wide15.08 in (38.30 cm) deep

Weight:Not including mounting tray:

18 lb 13 oz (8.53 kg)Including mounting tray:

20 lb 3 oz (9.15 kg)

Tracking Capability:Up to 35 intruder aircraftTracks intruder aircraft to a maximum closure rate of 1200 knots

Surveillance Range:Nominal 27 nmi; maximum 35 nmi

Display Range:5, 10, & 20 nmi when used with the CD605

Range Accuracy:±0.05 nmi (typical)

Bearing Accuracy:5° RMS (typical); 30° peak error


Chapter 6 – SpecificationsTRC Specs (Continued)

Table 6-1. TRC Specifications* (Continued)

*Specifications subject to change without notice.

Altitude Accuracy:±200 ft

Power Input Requirements:20 to 32.2 V dc, 120 W (maximum)

Transmitter Power Output:200 W peak (nominal)

Receiver Sensitivity:-74 dBm

Operating Temperature:-55 to +70 °C (-67 to +158 °F)

Storage Temperature:-55 to +85 °C (-67 to +185 °F)

Operating Altitude:55,000 ft maximum

Cooling:Internal fan

TSO Compliance:C118

RTCA Compliance:DO-160C Category:

F2-BA(NBM)XXXXXXZBABAUAXXXXXX


Chapter 6 – Specifications CD605 Specs

Table 6-2. CD605 Control Display Unit Specifications*

Part Number Definition:805-10007-005 – 2-button, white/cyan/amber CRT, black

faceplate, +5 V backlighting805-10007-006 – 2-button, white/cyan/amber CRT, gray

faceplate, +5 V backlighting805-10007-007 – 2-button, white/cyan/amber CRT, black

faceplate, +28 V backlighting805-10007-008 – 2-button, white/cyan/amber CRT, gray

faceplate, +28 V backlighting

Size:3.26 in (8.15 cm) high3.26 in (8.15 cm) wide8.81 in (22.03 cm) deep3ATI envelope with 0.25 in bezel protrusion

Weight:3 lb 1 oz (1.39 kg)

Viewing Angle:35° horizontal, 45° top, 20° bottom

Power Input Requirements:20 to 32.2 V dc, 20 W ±10%

Operating Temperature:-20 to +55 °C (-4 to +131 °F)

Storage Temperature:-55 to +70 °C (-67 to +158 °F)

Operating Altitude:55,000 ft maximum

Cooling:Internal fan

TSO Compliance:C113


F1-CA(NBM)XXXXXXZBABAUAXXX



Chapter 6 – Specifications

Table 6-3. NY156 TCAS Directional Antenna Specifications*


Directional Antenna Specs

Part Number:805-10003-001

Height:1.3 in (3.25 cm)

Weight:2.3 lb (1.04 kg)

Speed:Rated to 600 knots (0.9 Mach) @ 25,000 ft

Frequency:1,030-1,090 MHz

TSO Category:C118


F2-AC(CLM)XSFDFSXXXXXXXL(2A)X

Finish:Gloss white Skydrol®-resistant polyurethane paint


Chapter 6 – Specifications L-Band Antenna Specs

Table 6-4. NY152 L-Band Antenna Specifications*


Part Number:805-10005-001

Height:2.68 in (6.70 cm)

Weight:0.3 lb (0.14 kg)

Speed:Rated to 600 knots (0.9 Mach) @ 25,000 ft

Frequency:960-1,220 MHz

TSO Category:C66b, C74c

RTCA Compliance:DO-160A Category:

AE1/A/JXXXXXXXXXXX

Finish:Gloss white Skydrol®-resistant polyurethane paint

Record of Important InformationDealer Information

Name _______________________________________________

Address _____________________________________________

City, State, Zip ________________________________________

Telephone ___________________________________________

Equipment InformationDate of Purchase ____________ Installation Date ___________

TRC:Model Number_____________________________________

Part Number ______________________________________

Serial Number _____________________________________

Mod Letter ________________________________________

Firmware Version ___________________________________

CDU:Model Number_____________________________________

Part Number ______________________________________

Serial Number _____________________________________

Mod Letter ________________________________________

Directional Antenna:Model Number_____________________________________

Part Number ______________________________________

Serial Number _____________________________________

Mod Letter ________________________________________

L-Band Omnidirectional Antenna:Model Number_____________________________________

Part Number ______________________________________

Serial Number _____________________________________

Mod Letter ________________________________________

Note: To ensure that a new or repaired TCAS791 meets the TSO, meetsforeign government certification requirements, and meets L-3 Avionics Systemsperformance standards, your TCAS791 must be installed and tested by an L-3Avionics Systems authorized TCAS791 dealer.

009-10025-001 (Rev. G, 6/24/04)

L-3 Communications Avionics Systems, Inc.5353 52nd Street, S.E.Grand Rapids, MI 49512 USA(800)253-9525www.L-3com.com/as

TCAS791

for the traffic alert & collision avoidance system i · traffic alert & collision avoidance...

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