TO: HOLDERS OF THE TERRAIN AND TRAFFIC COLLISION Pilots Guide Rev4.pdf · 2013-07-05 · Printed in...

Printed in U.S.A. Pub. No. 8000264--001Highlights

Revised December 2008

E2008 ACSSPage 1 of 4

Aviation Communication and Surveillance Systems19810 North 7th Ave.Phoenix, Arizona 85027--4741U.S.A.

TO: HOLDERS OF THE TERRAIN AND TRAFFIC COLLISIONAVOIDANCE SYSTEM PILOT’S GUIDE, ACSS PUB. NO.8000264--001

REVISION NO. 4 DATED DECEMBER 2008

HIGHLIGHTS

Pages that are added and revised are identified below together with thehighlights of this revision. All revised pages have a new publicationdate, as identified in the List of Effective Pages. Changes in text areidentified by a revision bar opposite the change.

Remove the out--of--date pages and put the added and revised pagesinto your copy of this manual. On the Record of Revisions page writethe Revision Number and Revision Date.

Page Description of Change

T--1, T--2 Changed to show the revision date.

RR--1 Changed to show the revision and date.

LEP--1 thruLEP--4

Changed to show the changed pages in guide.

TC--3 thru TC--6,TC--8, TC--9

Changed to show where information is locatedin this guide.

1--1 Updated information in “Description”.

1--5 Updated information in “Reactive WindshearSystem”.

3--17 Updated Figure 3--17.

9--1 Updated information in the TAWS Introductionparagraph.





9--2 Updated Table 9--1 and information in “TAWSSystem Components” paragraph.

9--3 Updated information in “Ground CollisionAvoidance Module” paragraph.

9--4, 9--5 Updated information in “Collision Predictionand Alerting” paragraph and added Obstaclefunction information. Updated Figure 9--3.

9--6 Updated information in “Aircraft PersonalityModule”.

9--7 Updated information in “Terrain Display”.

9--8 Updated information in “Pilot Reactions toTAWS Alerts”.

9--9 Updated information in “TAWS Constraints”.

9--10 Updated information in “Predictive andReactive Warnings”.

9--11, 9--12 Updated information in “Coverage of theTAWS Terrain Database”.

9--13 Updated information in “Obstacle Database”and removed note from “Aircraft Altitude”paragraph.

9--14 Updated information in “Perspective View forTerrain Detection Envelope”.

9--15, 9--16 Changed title from “Terrain Caution Alert andWarning Envelopes” to “Terrain CautionWarning, and Avoid Envelopes”. Updatedinformation in “Terrain Caution Warning, andAvoid Envelopes”. Added new Figure 9--6 andupdated title of Fig 9--7. All figure numbersfollowing were changed to reflect addition andhave new revision.

9--17, 9--18 Moved heading “Terrain Caution Envelope” tofollow Figure 9--8. Updated information in“Terrain Warning Envelope”. Added newinformation “Terrain Avoid Envelope”.






9--21 Updated information in “Terrain Caution Alertsand Warnings”.

9--24 Updated note in MODE 1 section of “GPWSModes of Operation”.

9--37 Updated information in MODE 6 section of“GPWS Modes of Operation”.

10--1, 10--3 Updated information in “TAWS Controls”.


10--3 Updated information in “TAWS Displays”.

10--4, 10--6 Updated information in “Terrain InformationDisplay” and updated Figure 10--2 title.

10--7 Updated Table 10--1 and Table 10--2.

10--9 Added Table 10--3.

10--15 Text relocated; no data changed. Added noteto “Terrain Caution and Warning Displays”.

10--16, 10--17,10--18

Added “Obstacle Caution and WarningDisplays”. Added new Figure 10--8, 10--9, and10--10.

10--18, 10--19 Added “Terrain Hazard Display”. Added newFigure 10--11.

10--20, 10--21 Added “Terrain Eleview Display”. Added newFigure 10--12 and 10--13.

10--15 Added note in “Emergency Procedures”.

10--22, 10--23 Updated information in “Operating ModeRequirements”.

10--25, 10--26 Added “Abnormal Procedures”. Added newFigure 10--12 and 10--13.


10--29 Updated TAWS Self--Test.

10--30 Updated information in “TAWS Self--TestAnnunciations”.





10--31 Updated information in “TAWS SystemExtended Self--Test”.

10--32 Updated Table 10--5.


11--4 Updated information in “Visual Alerts”.


12--1 Updated information in “Reactive WindshearSystem”.

12--2 Added note for Figure 12--1 in “ReactiveWindshear System”.

13--1 thru 13--4 Added new acronyms to “Acronyms andAbbreviations” Section.

G--1 thru G--4 Added Appendix G, “Color Schemes”.

Index--1 thruIndex 6

Updated the Index.

Printed in U.S.A. Pub. No. 8000264--001 February 2003Revised December 2008E2008 ACSS

Aviation Communication and Surveillance Systems19810 North 7th Ave.Phoenix, Arizona 85027--4741U.S.A.

Terrain andTrafficCollisionAvoidanceSystem

Pilot’s Guide

This ACSS T2CAS Pilot’s Guide was written as a training aid to theoperation of the Terrain and Traffic Collision Avoidance System. Thisguide should not be used as an authorized checklist orprocedural aid replacing FAA or other certifying authority approvedflight manuals or checklists.

This manual provides guidance as a training aid for the ACSS T2CASsystem only. Operation of aircraft equipped with this system mustcomply with all governing air regulations for the flight, the ApprovedAircraft Flight Manual, and, if applicable, the specific airline operator’sapproved Operations Manual.

PROPRIETARY NOTICE

This document and the information disclosed herein are proprietarydata of ACSS. Neither this document nor the information containedherein shall be used, reproduced, or disclosed to others without thewritten authorization of ACSS, except to the extent required forinstallation or maintenance of recipient’s equipment.

NOTICE -- FREEDOM OF INFORMATION ACT (5 USC 552) ANDDISCLOSURE OF CONFIDENTIAL INFORMATION GENERALLY(18 USC 1905)

This document is being furnished in confidence by ACSS. Theinformation disclosed herein falls within exemption (b) (4) of 5 USC552and the prohibitions of 18 USC 1905.

Terrain and Traffic Collision Avoidance System

Record of Revisions8000264--001Rev 4 Dec 31/2008 RR--1

Use or disclosure of the information on this page is subject to the restrictions on the title page of this document.

Record of Revisions

Upon receipt of a revision, insert the latest revised pages and disposeof superseded pages. Enter revision number and date, insertion date,and the incorporator’s initials on this Record of Revisions. The typedinitial A is used when ACSS is the incorporator of the revision.

RevisionNumber

RevisionDate

InsertionDate By

1 15 Jul 2004 15 Jul 2004 A

2 1 Sep 2004 1 Sep 2004 A

3 15 Jun 2007 15 Jun 2007 A

4 30 Nov 2008 30 Nov 2008 A


8000264--001Rev 1 Jul 15/2004

Record of RevisionsRR--2


This page intentionally left blank.


8000264--001Rev 4 Dec 31/2008 LEP--1

List of Effective Pages



Original Feb 2003Revision Jul 2004Revision Sep 2004Revision Jun 2007Revision Dec 2008

Subheading and Page Revision Subheading and Page Revision

Title Page H 4

Proprietary Notice 3

Record of Revisions

RR--1 H 4

RR--2 1


LEP--1 H 4

LEP--2 H 4

LEP--3 H 4

LEP--4 H 4

Table of Contents

TC--1 1

TC--2 1

TC--3 H 4

TC--4 H 4

TC--5 3

TC--6 H 4

TC--7 1

TC--8 H 4

TC--9 H 4

TC--10 H 4

TC--11/TC--12 1

Introduction

1--1 H 4

1--2 3

1--3 3

1--4 1

1--5 H 4

1--6 1

TCAS System Description

2--1 1

2--2 3

2--3 3

2--4 1

2--5 2

2--6 1

2--7 1

2--8 2

2--9 1

2--10 1

2--11 1

2--12 1

TCAS Controls and Displays

3--1 1

3--2 1

3--3 1

3--4 1

3--5 1

3--6 3

3--7 3

3--8 1

3--9 1

3--10 1

3--11 1

3--12 1

3--13 1

3--14 2

3--15 1

3--16 1

3--17 H 4

3--18 1

3--19 1

3--20 1

3--21 3

3--22 1

TCAS Annunciators

4--1 3

4--2 1

4--3 1

4--4 1

4--5 1

4--6 1

4--7 3

4--8 3


8000264--001Rev 4 Dec 31/2008

List of Effective PagesLEP--2


TCAS Logic Parameters

5--1 3

5--2 3

5--3 1

5--4 1

Flight Crew Response toTCAS Advisories

6--1 3

6--2 3

6--3 1

6--4 1

6--5 1

6--6 1

6--7 1

6--8 1

TA and RA Responses

7--1 2

7--2 1

7--3 1

7--4 1

7--5 1

7--6 1

7--7 1

7--8 3

7--9 3

7--10 3

7--11 1

7--12 1

7--13 1

7--14 1

7--15 1

7--16 1

7--17 1

7--18 1

TCAS Operating Procedures

8--1 1

8--2 1

8--3 1

8--4 1

8--5 1

8--6 3

TAWS System Description

9--1 H 4

9--2 H 4

9--3 H 4

9--4 H 4

9--5 H 4

9--6 H 4

9--7 H 4

9--8 H 4

9--9 H 4

9--10 H 4

9--11 H 4

9--12 3

9--13 H 4

9--14 H 4

9--15 H 4

9--16 H 4

9--17 H 4

9--18 H 4

9--19 H 4

9--20 3

9--21 H 4

9--22 3

9--23 3

9--24 H 4

9--25 3

9--26 3

9--27 3

9--28 3

9--29 3

9--30 3

9--31 3

9--32 3

9--33 3

9--34 3

9--35 3

9--36 H 4

9--37 3

9--38 3

9--39 3

TAWS System Operation

10--1 H 4

10--2 3

10--3 H 4

10--4 H 4

10--5 H 4

10--6 H 4

10--7 H 4

10--8 H 4

10--9 H 4

10--10 3

10--11 3

10--12 3

10--13 3

10--14 H 4

10--15 H 4


8000264--001Rev 4 Dec 31/2008 LEP--3



10--16 H 4

10--17 H 4

10--18 H 4

10--19 H 4

10--20 H 4

10--21 H 4

10--22 H 4

10--23 H 4

10--24 3

10--25 H 4

10--26 H 4

10--27 3

10--28 H 4

10--29 H 4

10--30 3

TAWS and Reactive WindshearAnnunciators

11--1 H 4

11--2 3

11--3 3

11--4 H 4

11--5/11--6 H 1

Reactive Windshear System

12--1 3

12--2 H 4

Acronyms and Abbreviations

13--1 H 4

13--2 3

13--3 H 4

13--4 H 4

Appendix A

A--1 1

A--2 3

A--3 1

A--4 1

A--5 1

A--6 1

A--7 1

A--8 1

Appendix B

B--1 1

B--2 1

B--3 1

B--4 1

B--5 1

B--6 1

Appendix C

C--1 3

C--2 3

C--3 3

C--4 3

C--5 3

C--6 1

Appendix D

D--1 1

D--2 1

D--3 1

D--4 1

D--5 1

D--6 1

D--7 1

D--8 1

D--9 1

D--10 1

D--11 1

D--12 1

D--13 1

D--14 1

D--15 1

D--16 1

Appendix E

E--1 1

E--2 1

Appendix F

F--1 3

F--2 3

F--3 3

F--4 3

F--5 3

F--6 3

F--7 3

F--8 3

F--9 3

F--10 3

F--11 3

F--12 3

F--13 3

F--14 3

F--15 3

F--16 3


8000264--001Rev 4 Dec 31/2008

List of Effective PagesLEP--4


Appendix G

G--1 H 4

G--2 H 4

G--3 H 4

G--4 H 4

Index

Index--1 H 4

Index--2 H 4

Index--3 H 4

Index--4 H 4

Index--5 H 4

Index--6 H 4


8000264--001Rev 1 Jul 15/2004

Table of ContentsTC--1


Table of Contents

Section Page

1. INTRODUCTION 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Purpose 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Description 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traffic Alert and Collision Avoidance System 1-2. .Terrain Awareness Warning System 1-4. . . . . . . . . .Reactive Windshear System 1-5. . . . . . . . . . . . . . . .Global Positioning System 1-5. . . . . . . . . . . . . . . . . .

2. TCAS SYSTEM DESCRIPTION 2-1. . . . . . . . . . . . . . .

General Information 2-1. . . . . . . . . . . . . . . . . . . . . . . . . .System Capabilities 2-2. . . . . . . . . . . . . . . . . . . . . . . . . .TCAS Design and Integration 2-3. . . . . . . . . . . . . . . . . .TCAS II 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Other Transponder Systems 2-4. . . . . . . . . . . . . . . . . . .General Cautions 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . .TCAS System Components 2-6. . . . . . . . . . . . . . . . . . .System Theory 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCAS Advisories 2-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traffic Advisories 2-12. . . . . . . . . . . . . . . . . . . . . . . . . .Resolution Advisories 2-12. . . . . . . . . . . . . . . . . . . . . .

3. TCAS CONTROLS AND DISPLAYS 3-1. . . . . . . . . . .

Control Panel 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Display 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VSI/TRA Display 3-7. . . . . . . . . . . . . . . . . . . . . . . . . .Primary Flight and Navigation Displays 3-10. . . . . . .Modified Weather Indicator 3-12. . . . . . . . . . . . . . . . .

Resolution Advisory Vertical Speed Guidance 3-13. . . .Traffic Display Symbols 3-14. . . . . . . . . . . . . . . . . . . . . . .

Solid Red Square 3-14. . . . . . . . . . . . . . . . . . . . . . . . .Solid Amber Circle 3-14. . . . . . . . . . . . . . . . . . . . . . . . .Solid Blue Diamond 3-14. . . . . . . . . . . . . . . . . . . . . . . .Open or Hollow Blue Diamond 3-15. . . . . . . . . . . . . .Data Tags 3-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Off Scale Traffic Advisories 3-16. . . . . . . . . . . . . . . . .No Bearing Advisories 3-16. . . . . . . . . . . . . . . . . . . . .

Example of VSI/TRA with Traffic Displayed 3-17. . . . . .Aural Messages 3-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traffic Advisory 3-18. . . . . . . . . . . . . . . . . . . . . . . . . . .Resolution Advisories 3-18. . . . . . . . . . . . . . . . . . . . . .Preventive or Weakening Advisory 3-18. . . . . . . . . . .


8000264--001Rev 1 Jul 15/2004



Table of Contents (cont)

Section Page

Corrective Resolution Advisories 3-19. . . . . . . . . . . .Increased Strength or ReversedCorrective Advisories 3-20. . . . . . . . . . . . . . . . . . . . .

Corrective, Weakening, or Restrictive Advisories 3-21Clear of Conflict 3-21. . . . . . . . . . . . . . . . . . . . . . . . . . .

4. TCAS ANNUNCIATORS 4-1. . . . . . . . . . . . . . . . . . . . . .

Mode Annunciators 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . .Failure Annunciators 4-3. . . . . . . . . . . . . . . . . . . . . . . . . .Self--Test Annunciators 4-6. . . . . . . . . . . . . . . . . . . . . . . .

5. TCAS LOGIC PARAMETERS 5-1. . . . . . . . . . . . . . . . .

Sensitivity Level 5-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Protected Area 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vertical Threshold 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . .Alarm Time 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example Calculations 5-4. . . . . . . . . . . . . . . . . . . . . . . . .

6. FLIGHTCREW RESPONSE TOTCAS ADVISORIES 6-1. . . . . . . . . . . . . . . . . . . . . . . .

Pilot Responsibilities 6-1. . . . . . . . . . . . . . . . . . . . . . . . . .Traffic Advisories 6-1. . . . . . . . . . . . . . . . . . . . . . . . . .Resolution Advisories 6-2. . . . . . . . . . . . . . . . . . . . . .Prioritization of Actions 6-3. . . . . . . . . . . . . . . . . . . . .

Expected Flightcrew Response 6-5. . . . . . . . . . . . . . . .Cockpit Resource Management 6-6. . . . . . . . . . . . . . . .

7. TA AND RA RESPONSES 7-1. . . . . . . . . . . . . . . . . . . .

Traffic Advisories 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Response to a Traffic Advisory 7-1. . . . . . . . . . . . . .

Resolution Advisories 7-2. . . . . . . . . . . . . . . . . . . . . . . . .Response to a Preventive RA 7-3. . . . . . . . . . . . . . . . . .Corrective Resolution Advisories 7-4. . . . . . . . . . . . . . .

Response to a Climb RA 7-4. . . . . . . . . . . . . . . . . . .Response to a Descend RA 7-5. . . . . . . . . . . . . . . .Response to a Crossing Climb RA 7-6. . . . . . . . . . .Response to a Crossing Descend RA 7-7. . . . . . . .Response to a Corrective Reduce Climb RA 7-8. .Response to a Corrective Reduce Descent RA 7-9

Strengthening Advisories 7-10. . . . . . . . . . . . . . . . . . . . . .Response to an Increase Climb RA 7-10. . . . . . . . . .


8000264--001Rev 3 Jun 15/2007




Section Page

Response to an Increase Descent RA 7-11. . . . . . . .Reversal Resolution Advisories 7-12. . . . . . . . . . . . . . . .

Response to a Climb Now RA 7-12. . . . . . . . . . . . . . .Response to a Descend Now RA 7-13. . . . . . . . . . . .

Weakening or Restrictive Advisories 7-14. . . . . . . . . . . .Adjust Climb or Descent Rate RA 7-14. . . . . . . . . . . .Corrective Non--Crossing, Maintain Rate RA 7-15. .Corrective Altitude Crossing, Maintain Rate RA 7-16

Clear of Conflict Advisory 7-17. . . . . . . . . . . . . . . . . . . . . .

8. TCAS OPERATING PROCEDURES 8-1. . . . . . . . . . .Communication and Coordination with ATC 8-1. . . . . .Operations 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Normal Operations 8-1. . . . . . . . . . . . . . . . . . . . . . . .Mode Annunciators 8-1. . . . . . . . . . . . . . . . . . . . . . . .Non--Normal Operations 8-2. . . . . . . . . . . . . . . . . . . .Failure Annunciators 8-3. . . . . . . . . . . . . . . . . . . . . . .Equipment Failures 8-5. . . . . . . . . . . . . . . . . . . . . . . .

9. TAWS SYSTEM DESCRIPTION 9-1. . . . . . . . . . . . . . .TAWS Introduction 9-1. . . . . . . . . . . . . . . . . . . . . . . . . . .Non--Airbus T2CAS Part Numbers 9-2. . . . . . . . . . . . . .TAWS System Components 9-2. . . . . . . . . . . . . . . . . . .

Ground Collision Avoidance Module (GCAM) 9-3. .Collision Prediction and Alerting (CPA) 9-4. . . . . . .GPS Receiver 9-6. . . . . . . . . . . . . . . . . . . . . . . . . . . .Aircraft Personality Module (APM) 9-6. . . . . . . . . . .Terrain Display 9-7. . . . . . . . . . . . . . . . . . . . . . . . . . . .TAWS Control Panel 9-7. . . . . . . . . . . . . . . . . . . . . . .

TAWS Theory and Description 9-8. . . . . . . . . . . . . . . . .Pilot Reactions to TAWS Alerts 9-8. . . . . . . . . . . . . . . . .

TAWS Constraints 9-9. . . . . . . . . . . . . . . . . . . . . . . . .Predictive and Reactive Warnings 9-10. . . . . . . . . . .Terrain Database 9-10. . . . . . . . . . . . . . . . . . . . . . . . . .Coverage of the TAWS Terrain Database 9-11. . . . .Database Update 9-11. . . . . . . . . . . . . . . . . . . . . . . . . .Airport Database 9-13. . . . . . . . . . . . . . . . . . . . . . . . . .Obstacle Database 9-13. . . . . . . . . . . . . . . . . . . . . . . .Aircraft Altitude 9-13. . . . . . . . . . . . . . . . . . . . . . . . . . .Perspective View for Terrain Detection EnvelopeBoundaries 9-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Terrain Caution, Warning, and Alert Envelopes 9-15Convergence Envelope 9-22. . . . . . . . . . . . . . . . . . . .GPWS Modes of Operation 9-23. . . . . . . . . . . . . . . . .


8000264--001Rev 4 Dec 31/2008




Section Page

Reactive Windshear System 9-38. . . . . . . . . . . . . . . .Cold Weather Operations 9-39. . . . . . . . . . . . . . . . . . . . .

10. TAWS SYSTEM OPERATION 10-1. . . . . . . . . . . . . . . . .

TAWS Controls 10-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TAWS Displays 10-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Terrain Information Display 10-4. . . . . . . . . . . . . . . . .Terrain Advisory Line Display 10-10. . . . . . . . . . . . . . .Terrain Caution and Warning Displays 10-12. . . . . . . .Obstacle Caution and Warning Displays 10-16. . . . . .Terrain Hazard Display 10-18. . . . . . . . . . . . . . . . . . . . .Terrain Eleview Display 10-20. . . . . . . . . . . . . . . . . . . . .

Operating Mode Requirements 10-22. . . . . . . . . . . . . . . . .Abnormal Procedures 10-25. . . . . . . . . . . . . . . . . . . . . . . . .

CPA Mode Manual Deactivation 10-25. . . . . . . . . . . . .Reactive Modes (GPWS Modes) Deactivation 10-25.

Emergency Procedures 10-26. . . . . . . . . . . . . . . . . . . . . . .TAWS Self--Test 10-27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TAWS Self--Test Annunciations 10-31. . . . . . . . . . . . . . . . .TAWS Self--Test Annunciations with Windshear 10-32. .TAWS System Extended Self--Test 10-32. . . . . . . . . . . . .Non--Airbus T2CAS Self--Tests 10-33. . . . . . . . . . . . . . . . .

11. TAWS AND REACTIVE WINDSHEARANNUNCIATORS 11-1. . . . . . . . . . . . . . . . . . . . . . . . . .

Types of Annunciators 11-1. . . . . . . . . . . . . . . . . . . . . . . .Aural Alert Priority 11-1. . . . . . . . . . . . . . . . . . . . . . . . .Aural Alerts 11-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Visual Alerts 11-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12. REACTIVE WINDSHEAR SYSTEM 12-1. . . . . . . . . . . .

13. ACRONYMS AND ABBREVIATIONS 13-1. . . . . . . . . .

APPENDIX AFREQUENTLY ASKED QUESTIONS A--1. . . . . . . . .

APPENDIX BSUPPLEMENTAL INFORMATION FORTCAS CHANGE 7 B--1. . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction B--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Detailed Explanation B--1. . . . . . . . . . . . . . . . . . . . . . . . . .

Display Altitude Filtering B--1. . . . . . . . . . . . . . . . . . . .


8000264--001Rev 3 Jun 15/2007




Section Page

Display Traffic Numbering/Priority Filtering B--2. . . .ATCRBS Intruder On Ground Filtering Logic B--2. .Antenna Patterning B--3. . . . . . . . . . . . . . . . . . . . . . . .On Ground Aircraft Indication B--3. . . . . . . . . . . . . . .Transponder Tracking/Secondary Surveillance B--3Interference Limiting B--4. . . . . . . . . . . . . . . . . . . . . . .Multipath B--5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ATC Radar Coverage B--6. . . . . . . . . . . . . . . . . . . . . .

Summary B--6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

APPENDIX CGLOSSARY C--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Advisory C--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Alert C--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ATCRBS (Air Traffic ControlRadar Beacon System) C--1. . . . . . . . . . . . . . . . . . .

Caution Area C--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .CFIT (Controlled Flight Into Terrain) C--1. . . . . . . . . .Collision Area C--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Decision Height C--2. . . . . . . . . . . . . . . . . . . . . . . . . . .Intruder C--2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Minimum Descent Altitude C--2. . . . . . . . . . . . . . . . . .Missed Approach C--2. . . . . . . . . . . . . . . . . . . . . . . . . .Mode--A C--2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mode--C C--3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mode--S C--3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Nuisance Alert C--4. . . . . . . . . . . . . . . . . . . . . . . . . . . .Other Traffic C--4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PDA -- (Premature Descent Alert). C--4. . . . . . . . . . .Proximate Traffic C--4. . . . . . . . . . . . . . . . . . . . . . . . . .Resolution Advisory (RA) C--4. . . . . . . . . . . . . . . . . . .TCAS Function in T2CAS C--4. . . . . . . . . . . . . . . . . . .TCAS 2000 C--5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCAS II C--5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Traffic Advisory (TA) C--5. . . . . . . . . . . . . . . . . . . . . . .Warning Area C--5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Weakening Advisory C--5. . . . . . . . . . . . . . . . . . . . . . .

APPENDIX DELECTRONIC FLIGHT INSTRUMENTDISPLAYS FOR TCAS D--1. . . . . . . . . . . . . . . . . . . . . .

Boeing Displays D--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Airbus Displays D--6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MD--11 Displays D--15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


8000264--001Rev 4 Dec 31/2008




Section Page

APPENDIX EBIBLIOGRAPHY E--1. . . . . . . . . . . . . . . . . . . . . . . . . . .

APPENDIX FAIRBUS--SPECIFIC APPLICATIONS F--1. . . . . . . . .

Airbus T2CAS Part Numbers F--1. . . . . . . . . . . . . . . . . . .No Altitude Callouts F--1. . . . . . . . . . . . . . . . . . . . . . . . . .Wind Effects F--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Basic GPWS Mode Specific for Airbus F--1. . . . . . .Flight Management Landing (FLS) System F--4. . . .Airbus -- Pushbutton Switches,GPWS Control Panel and ECAM Messages F--4.

GPWS/FLAP MODE Pushbutton Switch F--5. . . . . .GPWS/G/S MODE Pushbutton Switch F--5. . . . . . .GPWS/SYS Pushbutton Switch F--5. . . . . . . . . . . . .GPWS/TERR Pushbutton Switch F--5. . . . . . . . . . . .GPWS/LDG FLP 3 Pushbutton (SA only) F--5. . . . .PULL UP/GPWS (CAPT and F/O)Pushbutton Switches F--5. . . . . . . . . . . . . . . . . . . . .

TERR ON ND (CAPT and F/O)Pushbutton Switches F--5. . . . . . . . . . . . . . . . . . . . .

Other Indication (ECAM only) F--5. . . . . . . . . . . . . . .Terrain Hazard Display for Airbus Configuration F--7Premature Descent Alert (PDA) F--8. . . . . . . . . . . . .Airbus Background Terrain Display on NDs F--9. . .Terrain Alerts Display F--9. . . . . . . . . . . . . . . . . . . . . .Airbus Maintenance Interface to the OMC F--11. . . .Pilot Initiated TAWS Go/No GoSelf--Test On Ground F--13. . . . . . . . . . . . . . . . . . . . .

Airbus Self--Test Aurals F--15. . . . . . . . . . . . . . . . . . . .

APPENDIX GCOLOR SCHEMES G--1. . . . . . . . . . . . . . . . . . . . . . . . .

Terrain Display Color Schemes G--1. . . . . . . . . . . . . . . . .

Index Index--1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


8000264--001Rev 1 Jul 15/2004




List of IllustrationsFigure Page

2--1 Basic TCAS System Diagram 2-6. . . . . . . . . . . . . . . . .2--2 FAA TCAS II Caution and Warning Areas 2-10. . . . . . .2--3 FAA TCAS II Protection and Services 2-11. . . . . . . . . .3--1 ATCRBS/Mode--S/TCAS Control Panel 3-1. . . . . . . .3--2 Dual Mode S/TCAS Control Panel 3-2. . . . . . . . . . . . .3--3 Flat Panel VSI/TRA Indicator 3-7. . . . . . . . . . . . . . . . .3--4 VSI/TRA Range Measurements 3-9. . . . . . . . . . . . . . .3--5 Boeing EIS PFD – Climb RA Shown 3-10. . . . . . . . . . .3--6 Boeing EIS ND – TCAS Mode 3-11. . . . . . . . . . . . . . . .3--7 Modified Weather Indicator 3-12. . . . . . . . . . . . . . . . . . .3--8 VSI/TRA Command Indicators 3-13. . . . . . . . . . . . . . . .3--9 Indicators and Symbols 3-17. . . . . . . . . . . . . . . . . . . . . .4--1 TA ONLY Annunciator 4-1. . . . . . . . . . . . . . . . . . . . . . .4--2 TCAS OFF Annunciator 4-2. . . . . . . . . . . . . . . . . . . . . .4--3 TCAS FAIL Indicator 4-3. . . . . . . . . . . . . . . . . . . . . . . . .4--4 RA FAIL Indicator 4-3. . . . . . . . . . . . . . . . . . . . . . . . . . .4--5 TD FAIL Indicator 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . .4--6 VSI FAIL and RA FAIL Indicator 4-4. . . . . . . . . . . . . . .4--7 Red X Display 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4--8 TCAS Self--Test Annunciator

on VSI/TRA Display 4-6. . . . . . . . . . . . . . . . . . . . . . . . .4--9 Extended Test Display – Main Menu 4-7. . . . . . . . . . .5--1 TCAS Sensitivity Levels and Altitude Layers 5-2. . . .7--1 Traffic Advisory Display 7-1. . . . . . . . . . . . . . . . . . . . . .7--2 Preventive Resolution Advisory 7-3. . . . . . . . . . . . . . .7--3 Corrective Resolution Advisory 7-4. . . . . . . . . . . . . . . .7--4 Descend Resolution Advisory 7-5. . . . . . . . . . . . . . . . .7--5 Crossing Climb Resolution Advisory 7-6. . . . . . . . . . .7--6 Crossing Descend Resolution Advisory 7-7. . . . . . . . .7--7 Reduce Climb Resolution Advisory 7-8. . . . . . . . . . . .7--8 Reduce Descent Resolution Advisory 7-9. . . . . . . . . .7--9 Increase Climb Resolution Advisory 7-10. . . . . . . . . . . .7--10 Increase Descent Resolution Advisory 7-11. . . . . . . . .7--11 Climb Now Resolution Advisory 7-12. . . . . . . . . . . . . . .7--12 Descend Now Resolution Advisory 7-13. . . . . . . . . . . .7--13 Adjust Climb or Descent Rate

Resolution Advisory 7-14. . . . . . . . . . . . . . . . . . . . . . . . .7--14 Corrective Non--Crossing Maintain Rate

Resolution Advisory 7-15. . . . . . . . . . . . . . . . . . . . . . . . .7--15 Corrective Altitude Crossing Maintain

Rate Resolution Advisory 7-16. . . . . . . . . . . . . . . . . . . . .


8000264--001Rev 4 Dec 31/2008




List of Illustrations (cont)

Figure Page

7--16 Clear of Conflict Advisory 7-17. . . . . . . . . . . . . . . . . . . . .8--1 TA ONLY Annunciator 8-1. . . . . . . . . . . . . . . . . . . . . . .8--2 TCAS OFF Annunciator 8-2. . . . . . . . . . . . . . . . . . . . . .8--3 TCAS FAIL Annunciator 8-3. . . . . . . . . . . . . . . . . . . . . .8--4 RA FAIL Annunciator 8-3. . . . . . . . . . . . . . . . . . . . . . . .8--5 TD FAIL Annunciator 8-4. . . . . . . . . . . . . . . . . . . . . . . .8--6 Red X Display 8-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8--7 RA FAIL and VSI FAIL Annunciators 8-5. . . . . . . . . . .9--1 Basic TAWS System 9-3. . . . . . . . . . . . . . . . . . . . . . . . .9--2 Typical GCAM Interfaces 9-4. . . . . . . . . . . . . . . . . . . . .9--3 CPA Function and Reactive Modes 9-5. . . . . . . . . . . .9--4 Terrain Database Resolution 9-12. . . . . . . . . . . . . . . . . .9--5 Aircraft Altitude Determination 9-14. . . . . . . . . . . . . . . .9--6 Terrain Detection Envelope Boundaries 9-15. . . . . . . .9--7 Caution, Warning, and Avoid Clearance Sensors 9-169--8 Horizontal Terrain Conflict Envelope 9-17. . . . . . . . . . .9--9 Pull Up Warning 9-19. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9--10 Avoid Terrain Warning 9-20. . . . . . . . . . . . . . . . . . . . . . .9--11 TAWS Convergence Envelope 9-22. . . . . . . . . . . . . . . .9--12 GCAM CFIT Protection and Flight Phases 9-23. . . . . .9--13 Sink Rate Caution and Pull Up

Warning Envelopes for Reactive Mode 1 9-25. . . . . . .9--14 Terrain Caution and Pull Up Warning

Envelopes for Mode 2 9-27. . . . . . . . . . . . . . . . . . . . . . . .9--15 Don’t Sink Caution Envelope for Mode 3 9-29. . . . . . . .9--16 Too Low Terrain/Gear/Flaps

Envelope for Mode 4 9-31. . . . . . . . . . . . . . . . . . . . . . . . .9--17 Excessive Descent Below Glideslope

Envelope for Mode 5 9-34. . . . . . . . . . . . . . . . . . . . . . . . .9--18 Excessive Bank Angle Envelope for Mode 6 9-36. . . .10--1 Typical TAWS Control Panel 10-3. . . . . . . . . . . . . . . . . .10--2 Example of Terrain Display Patterns for Various

Terrain Elevations 10-5. . . . . . . . . . . . . . . . . . . . . . . . . . .10--3 Obstacle Display Patterns for Various

Obstacle Elevations 10-6. . . . . . . . . . . . . . . . . . . . . . . . .10--4 Terrain Advisory Line 10-10. . . . . . . . . . . . . . . . . . . . . . . .10--5 Terrain Caution Alert 10-12. . . . . . . . . . . . . . . . . . . . . . . . .10--6 Pull Up Warning 10-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . .10--7 Avoid Terrain Warning Display 10-14. . . . . . . . . . . . . . . .10--8 Obstacle Caution Display 10-16. . . . . . . . . . . . . . . . . . . . .10--9 Pull Up Warning Display 10-17. . . . . . . . . . . . . . . . . . . . . .


8000264--001Rev 4 Dec 31/2008




List of Illustrations (cont)

Figure Page

10--10 Avoid Obstacle Warning Display 10-18. . . . . . . . . . . . . . .10--11 Example of a Terrain Hazard Display Showing

Avoid Terrain Warning Display 10-19. . . . . . . . . . . . . . . .10--12 Example of an Eleview Spread 10-20. . . . . . . . . . . . . . . .10--13 Terrain Eleview Display 10-21. . . . . . . . . . . . . . . . . . . . . .10--14 Sample TAWS Display Test Pattern 10-27. . . . . . . . . . . .10--15 Sample TAWS Display Test Pattern

with Eleview Enabled 10-28. . . . . . . . . . . . . . . . . . . . . . . .12--1 Windshear Detection 12-2. . . . . . . . . . . . . . . . . . . . . . . .F--1 Too Low Terrain/Gear/Flaps Envelope

for Mode 4 (Airbus) F--3. . . . . . . . . . . . . . . . . . . . . . . . . .F--2 T2CAS--TAWS Controls (LR) F--4. . . . . . . . . . . . . . . . . .F--3 T2CAS--TAWS Controls (SA) F--4. . . . . . . . . . . . . . . . .F--4 Messages Displayed on EWD SD F--6. . . . . . . . . . . . .F--5 Background Computation F--7. . . . . . . . . . . . . . . . . . . .F--6 Terrain Background Display F--9. . . . . . . . . . . . . . . . . . .F--7 TERR AHEAD Caution Indicator F--10. . . . . . . . . . . . . .F--8 Terrain Ahead Pull Up Indicator F--10. . . . . . . . . . . . . . .F--9 Avoid Terrain Indicator F--11. . . . . . . . . . . . . . . . . . . . . . .F--10 Cockpit Indications (A320 Family) F--13. . . . . . . . . . . . .F--11 Self--Test Pattern F--14. . . . . . . . . . . . . . . . . . . . . . . . . . . .G--1 Alternate Terrain Color Scheme I Display G--3. . . . . . .G--1 Alternate Terrain Color Scheme I G--4. . . . . . . . . . . . . .

List of TablesTable Page2--1 System Capabilities 2-2. . . . . . . . . . . . . . . . . . . . . . . . .3--1 Mode--Selector Switch Positions 3-3. . . . . . . . . . . . . .3--2 Typical Display Formats and Functions 3-8. . . . . . . . .3--3 VIS/TRA Range Settings 3-9. . . . . . . . . . . . . . . . . . . . .5--1 TCAS 2000 Logic Parameter Values 5-3. . . . . . . . . . .9--1 Non--Airbus T2CAS Part Numbers 9-2. . . . . . . . . . . . .9--2 Bank Angle Limits for Excessive Bank

Angle Caution 9-34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9--3 Altitude Callouts 9-36. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9--4 DH and MDA Callouts 9-38. . . . . . . . . . . . . . . . . . . . . . .10--1 Terrain Display Patterns for Various

Terrain Elevations 10-7. . . . . . . . . . . . . . . . . . . . . . . . . . .10--2 Terrain Display Patterns for Various Terrain

Elevations when Aircraft is in the Vicinityof the Airport 10-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


8000264--001Rev 4 Dec 31/2008




List of Tables (cont)

Table Page

10--3 Obstacle Display Patterns for Various ObstacleElevations 10-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10--4 TAWS Self--Test Failure Annunciators 10-31. . . . . . . . . .10--5 Non--Airbus T2CAS Self--Tests 10-33. . . . . . . . . . . . . . . .11--1 Selectable Aural Alerts 11-1. . . . . . . . . . . . . . . . . . . . . . .11--2 TAWS and Reactive Windshear

Selectable Aural Alerts 11-4. . . . . . . . . . . . . . . . . . . . . . .11--3 TAWS and Reactive Windshear

Visual Annunciators 11-5. . . . . . . . . . . . . . . . . . . . . . . . .F--1 Airbus T2CAS Part Numbers F--1. . . . . . . . . . . . . . . . . .F--2 Airbus Terrain Display Colors for Various

Terrain Elevations F--8. . . . . . . . . . . . . . . . . . . . . . . . . . .F--3 Airbus Maintenance Interface to the OMC F--12. . . . . .G--1 Airbus Maintenance Interface to the OMC G--1. . . . . .


8000264--001Rev 4 Dec 31/2008 1-1

Introduction


1. Introduction

PURPOSE

Thismanual is designed to familiarize flightcrewswith theACSSTerrainand Traffic Collision Avoidance System known as T2CAS. This manualcovers the basic system concepts and fundamentals, operatingprinciples and procedures, and system limitations.

All flightcrewmembersmust complete an approved training courseandhave that completion documented in their training records in order tobecome T2CAS qualified.

DESCRIPTION

T2CAS is an integrated system that combines the following functionsinto a single line replaceable unit (LRU):

D Traffic Alert and Collision Avoidance System II (TCAS II) (withChange 7), also known as Airborne Collision Avoidance System II(ACAS II)

D Terrain awareness warning system (TAWS)

D Reactive windshear system (RWS) (optional)

D Global positioning system (GPS) (optional).

D Ground proximity warning system (GPWS)


8000264--001Rev 3 Jun 15/2007

Introduction1-2


Traffic Alert and Collision Avoidance System

The TCAS function of the T2CAS design is based on ACSS’s TCAS2000 product (with Change 7). The TCAS function is an independent,onboard collision avoidance system designed to assist flightcrews inavoiding midair collisions. TCAS must be turned on when conductingflight operations in airspace requiring use of the TCAS system. Whenactivated, TCAS acts as a backup means of collision protection fromother aircraft that have an air traffic control radar beacon system(ATCRBS) or Mode--S Transponder turned on and functioning. Thisprotection is not given when a non--International Civil AviationOrganization (ICAO) compliant transponder system is enabled.

TCAS continually surveys the airspace around the host aircraft byactively interrogating and seeking replies from the transponders ofother aircraft in the vicinity. TCAS recognizes replies from aircraftequipped with ICAO Mode--A, Mode--C, or Mode--S Transponders anddetermines the range, relative bearing, and the relative altitude of theother aircraft.

NOTE: The relative altitude of the other aircraft can only bedetermined if:1. That aircraft has altitude reporting equipment,2. That equipment is functioning properly, and3. Altitude reporting is selected on.

Using this information, TCAS predicts flight paths, estimates theseparation at the closest point of approach (CPA), and determines if apotential conflict exists. If a conflict is detected, the system givesguidance for the optimum vertical avoidance maneuver.

NOTES: 1. TCASmust be able to determine range and altitude ofthe other aircraft before it can determine if a potentialconflict exists.

2. In this Pilot’s Guide, CPA refers to “closest point ofapproach” in the context of TCAS operation, and“collision prediction and alerting” in the context ofTAWS operation.


8000264--001Rev 3 Jun 15/2007 1-3

Introduction


TCAS also receives inputs from other systems on board the hostaircraft, including information about the aircraft’s performancecapabilities. This information is considered as the system resolvesconflicts.

TCAS surrounds itself with a protected volume of airspace known asthe collision area. Since TCAS is a time--based system, the size andshape of the collision area varies with the intruder’s closure rate andrelative bearing. If the flight path of an intruding aircraft is predicted topenetrate the collision area, the system informs the crew with bothvisual and aural annunciators. TCAS generates two levels ofadvisories: traffic advisories (TA)s and resolution advisories (RA)s.These advisories are intended to preserve or increase the verticalseparation needed to avoid intruder aircraft. The TCAS system tracksup to 50 aircraft that are predicted to penetrate the collision area whenresolving encounters.

One of the TCAS display options is the ACSS vertical speedindicator/traffic and resolution advisory (VSI/TRA) display. This displayreplaces the original VSI at each pilot station and combines the verticalspeed information with traffic and resolution advisories. With the ACSSVSI/TRA, up to 28 aircraft can be displayed. Other display optionsinclude flat panel or glass cockpit systems which have enhancedcapabilities.


8000264--001Rev 1 Jul 15/2004

Introduction1-4


Terrain Awareness Warning System

The TAWS function (with optional windshear capability) in T2CAS wasdeveloped by Thales Avionics. It is contained in a separate andautonomous module inside the T2CAS LRU called the ground collisionavoidance module (GCAM). GCAM features an innovative designaimed at preventing controlled flight into terrain (CFIT) accidents bygiving the crew timely alerts based on predicted terrain obstacleclearanceprofiles, calculatedwith real timeactual aircraft performance.This results in a significant improvement in CFIT safety margins andrepresents a significant advance in capability from the older groundproximity warning system (GPWS) technology, which gives warningsbased on predicted time to terrain impact.

TAWS generates alerts to inform the flightcrew that the terrain aheadof the aircraft on its intended flight path poses a hazard to safe flight.TAWS is intended to warn the flightcrew of hazards that could result incontrolled flight into terrain with sufficient time for them to assess thesituation and determine the best remedial action to safely avoid thehazard. TAWS generates a terrain caution alert, a pull--up warning,and/or an avoid terrain warning, depending on the aircraft situationwithregard to the terrain.

The TAWS design allows for special situations where aircraft areoperating according to approved procedures at altitudes significantlybelow the surrounding local terrain height (for example, approaches insteep valleys). The TAWS design constructs a predictive alert sensorthat is based on the actual performance capability of the aircraft. Thisdesign minimizes nuisance alerts and enhances crew confidence thatTAWS generated alerts represent real threats.

The TAWS functions in T2CAS also include the following:

D Reactive alert modes referenced in DO--161a and required by TSOC151a. (These reactive alert modes are also known as GPWSmodes.)

D Optional reactive windshear detection to warn the flightcrew if theaircraft is approaching a dangerous windshear condition.

The TAWS system in T2CAS meets TSO--C151a Class A.


8000264--001Rev 4 Dec 31/2008 1-5

Introduction



The optional reactive windshear function in T2CAS continuouslymonitors aircraft performance on both takeoff and approach in order toidentify the presence of a severe low--level, downburst/microburst--type shear. If these factors cause aircraft performance todecrease to a predetermined level, audio and visual warnings aregenerated indicating to the crew that the aircraft’s net performancecapability is deteriorating and rapidly approaching a critical state. Inaddition to the aural warning for decreasing aircraft performance, thewindshear system generates a caution when anincreasing--performance windshear is detected, thereby giving anadvance warning of decreasing--performance windshear. The optionalreactive windshear function in T2CAS meets TSO--C117a.

Global Positioning System

The GPS receiver in T2CAS is designed by CMC Electronics (formerlyCanadian Marconi Company). It is designed to meet requirements forenroute and terminal navigation according to TSO--C129a and TSOC145. The GPS receiver also supports the addition of space basedaugmentation system (SBAS) and wide area augmentation system(WAAS) with a software upgrade.

The GPS receiver is certified to TSOC129a Class B1/C1. Class B1/C1allows for navigation in enroute and terminal areas, as well asnon--precision approaches. The GPS receiver uses receiverautonomous integrity monitoring (RAIM) as required by TSO--C129a.The output of the GPS receiver is compatible with ARINC 743 GNSSUsystems to allow the GPS information to be used by systems externalto T2CAS.


8000264--001Rev 1 Jul 15/2004

Introduction1-6




8000264--001Rev 1 Jul 15/2004 2-1



2. TCAS System Description

GENERAL INFORMATION

TCAS is a situational awareness enhancement system in the samewaythat a windshear alerting system and TAWS/ground proximity systemalert the pilot to potential threats to the safety of the flight. However,windshear alerts andTAWSalerts, in that order, takepriority over TCASalerts. When TCAS is inhibited by either a windshear alert or a TAWSalert, the system reverts to the traffic alert only mode and aural TCASalerts are temporarily inhibited.

TCAS systems can be installed on an aircraft in a variety ofconfigurations. The number of TCAS computer units (CU), the numberof Mode--S Transponders, as well as the number and type of antennas,define the various configurations. This manual describes the basicfunction of each TCAS system component as it might be configured inthemost basic installation. Theapproved aircraft flight manual containsadditional information on the configuration and operation of the TCASsystem installed on any specific aircraft.


8000264--001Rev 3 Jun 15/2007

TCAS System Description2-2


SYSTEM CAPABILITIES

The system capabilities are listed in Table 2--1.

Description TCAS Capability

Mode--S surveillance range 80 nautical miles (NM) or more

ATCRBS surveillancerange

20 NM

ADS--B mode--S passivesurveillance range(when enabled by pinprogramming option)

Greater than 100 NM

Aircraft tracks 50

Horizontal closure rate(maximum)

1,200 Knots (kts)

Vertical closure rate(maximum)

10,000 feet per minute (fpm)

Escape maneuvercoordination with otherTCAS equipped aircraft

Yes

Directs normal escapemaneuvers by indicatingclimb or descent with arecommended verticalspeed (VS)

Yes

Directs enhanced escapemaneuvers by indicating anincreased climb or descent,or a reversal of direction ofclimb or descent

Yes

System CapabilitiesTable 2--1


8000264--001Rev 3 Jun 15/2007 2-3



TCAS DESIGN AND INTEGRATION

At the time of system installation and certification, the aircraftperformance characteristics in various configurations are analyzed. Ifnecessary, certain TCAS RA commands may be limited in order to becompatible with the aircraft’s climb capabilities. The required aircraftperformance is described in United States Federal AviationAdministration Advisory Circular AC 20--131A. The aircraft certificationprocess must assure the pilot that the aircraft is capable of complyingwith all RAs. When properly installed and certified, the TCAS systemcomplies with the following rules:

D No climb commands are issued when the aircraft can not achieve1,500 fpm.

D No increase--climb commands are issued when the aircraft can notachieve 2,500 fpm.

D No increase--descent commands are issued at altitudes less than1,450 feet (ft) above ground level (AGL) when the aircraft isdescending.

D No increase--descent commands are issued at altitudes less than1,650 ft AGL when the aircraft is climbing.

D No descend commands are issued at altitudes less than 1,000 ftAGL when the aircraft is descending.

D No descend commands are issued at altitudes less than 1,200 ftAGL when the aircraft is climbing.

D TCAS is in TA--only mode below 900 ft when descending.

D TCAS is in TA--only mode below 1,100 ft when climbing.

D No aural advisories are issued at an altitude below 600 ft AGLwhenthe aircraft is climbing.

D No aural advisories are issued at an altitude below 400 ft AGLwhenthe aircraft is descending.

TCAS II

The United States of America Federal Aviation Administration (FAA)has developed a set of minimum operational specifications for acollision avoidance system that has been identified as TCAS II. Thissystem has been mandated for use by certain aircraft operating inUnited States’ airspace. Other countries are also adopting similarstandards and are mandating use of a collision avoidance system intheir own airspace. Eurocontrol has mandated ACAS II (TCAS II withChange 7) for certain aircraft operating in European airspace.

The TCAS system that is a part of T2CAS has received TSO C119bapproval from the FAA.


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OTHER TRANSPONDER SYSTEMS

The TCAS system in T2CAS is compliant with ICAO standards forATCRBS Mode--A, Mode--C, and Mode--S. Air traffic control radarsalong international air routes through ICAO member countriesgenerally comply with ICAO standards.

Some countries may also use ATC radar systems that are notcompatible with the ICAO standard along domestic air routes. Forexample, this is the case in Russia, Uzbekistan, Ukraine, and otherCIScountries.

The TCAS system, when operating, can only detect other aircraft withoperating ICAO compliant transponders. TCAS cannot detect aircraftoperating non--ICAO compliant transponders. Continuous flightcrewvigilance is required when operating in any airspace.


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GENERAL CAUTIONS

CAUTIONS

1. TCASWILL NOT DETECT AIRCRAFT WITH INOPERATIVE ORNON--ICAO COMPLIANT TRANSPONDER SYSTEMS. DO NOTRELY SOLELY ON TCAS OR ATC FOR COLLISIONAVOIDANCE.

2. TCAS OPERATION REQUIRES A VALID ON--BOARD MODE--STRANSPONDER, A VALID BAROMETRIC ALTITUDE SOURCE,AND A VALID RADIO ALTITUDE SOURCE.

3. TCAS CANNOT DETECT INTRUDING AIRCRAFT IF THEON--BOARD MODE--S TRANSPONDER IS OFF OR INSTANDBY (STBY).

4. TCASCANNOT ISSUEANRAFOR INTRUDING TRAFFIC THATDOESNOTHAVEANOPERATING ICAOTRANSPONDERWITHAN OPERATIONAL ALTITUDE REPORTING FUNCTION.

5. IT IS NOT ALWAYS POSSIBLE TO INHIBIT AN RA WHEN ITWOULD BE APPROPRIATE TO DO SO DUE TO LIMITEDINPUTS TO THE TCAS. IN THESE CASES, TCAS MIGHTCOMMAND MANEUVERS THAT MAY SIGNIFICANTLYREDUCE STALL MARGINS. CONDITIONS WHEN THIS MAYOCCUR INCLUDE:

D BANK ANGLE EXCEEDS 15.

D ENGINE OUT (PILOT MUST SELECT TA ONLY).

D ABNORMAL CONFIGURATIONS (SUCH ASUNRETRACTED LANDING GEAR WHICH PLACES THEAIRCRAFT IN AN INAPPROPRIATE CONFIGURATIONWHEN THE RA OCCURS, ETC.).

D OPERATION AT TEMPERATURES BEYONDINTERNATIONAL STANDARD ATMOSPHERE (ISA).

D SPEEDS BELOW NORMAL OPERATING SPEEDS.

D BUFFET MARGIN LESS THAN 0.3g.

D TCAS--TO--TCAS RA SENSE REVERSAL.


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TCAS SYSTEM COMPONENTS

The basic TCAS system described in this manual consists of aircraftmounted antennas, a T2CAS LRU, aMode--S Transponder, the cockpitdisplays, and the control panel. (See Figure 2--1.)

Basic TCAS System DiagramFigure 2--1


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The TCAS function in the T2CAS LRU receives radio altitude, altitudealerter/flight control unit or mode control panel altitude (optional ARINC429 input), pressure altitude, airborneor on--ground status, and landinggear--up inputs from the respective aircraft systems. It is typicallyinstalled in theelectronics equipment compartment. TCAS interrogatestransponders on other aircraft, computes their locations, tracks theirpaths, issues visual advisories to the TCAS display, and issues auralannouncements to the pilot through the cockpit audio system. It is thecore of the TCAS system.

The TCAS system has at least one (and normally two) Mode--STransponders installed in the electronics equipment compartment. Thetransponder responds to Mode--A, Mode--C, and Mode--Sinterrogations fromATC radar systemsaswell as other TCASequippedaircraft. Every Mode--S equipped aircraft has a unique address thatenables direct data communications by compatible systems. Theaddress is assigned to a specific aircraft by the ICAO and ispermanently wired to each Mode--S Transponder installed on--board.TCAS uses this addressing capability to communicate directly withMode--S equipped intruders to coordinate and resolve potentialconflicts. This ICAO address is independent of the 4096 identificationcodes assigned by ATC during a flight. The Mode--S Transponder alsopasses pressure altitude and control panel data to the TCAS.

Each pilot has a VSI/TRA display in the usual location for a VSI, or theTCAS information and display is integrated in the electronic flightinstrument system (EFIS) displays. In an analog system installation, apressure transducermodule connected to the samestatic sourceas thealtimeter can give an electrical altitude rate signal to the VSI/TRA fordisplay if the air data computer (ADC) is unable to generate thenecessary signal format.

The Mode--S Transponder/TCAS control panel is typically located onthe center pedestal. The pilot uses the control panel to set TCAS andMode--S Transponder operating modes, to set ATC radar reply codes,and to verify system operation.

TCAS equipped aircraft have one TCAS directional antenna mountedon the top of the aircraft and one antenna (either directional ornon--directional) mounted on the bottom. The Mode--S Transponderalso requires top and bottom non--directional antennas. Thus, a total offour antennas are required for proper TCAS operation. An antennacoaxial switch canbeused to switch the transponder antennasbetweenthe No. 1 and No. 2 transponder systems.

Additional descriptive information can be found in the T2CAS SystemDescription and Installation Manual.


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SYSTEM THEORY

TCAS establishes a volume of space around an aircraft called thecollision area. The size varies with altitude. TCAS protects the collisionarea from penetration by other aircraft based on their rate of closureboth in range and altitude. TCAS continually surveys the airspacearound the aircraft and looks for transponder replies from other aircraft.These replies are tracked and a flight path for each detected aircraft ispredicted based on its track.

With the optional implementation of an altitude alerter or other altitudeinput (ARINC 429), the intent of equipped aircraft is coordinated tofurther refine resolution of a potential conflict. With this option, an RAis prevented from weakening to a “level off” (an RA recommending areduction in vertical rate to 0 fpm) before the altitude set--point has beenachieved by the aircraft.

The system uses a mathematical formula to calculate the closure rateand time to closest point of approach. Up to 50 aircraft can be trackedsimultaneously by TCAS. Any aircraft path that is predicted topenetratethe collision area surrounding the TCAS aircraft results in an RA whichhas the intended function of increasing the separation between theaircraft.

More specifically, TCAS creates two volumes of protected airspacearound the host aircraft called the warning area and the caution area.TCAS is a time--based system; that is, TAs and RAs are generated sothat the crew has about the same warning time regardless of thegeometry of the conflict. The system adjusts the size of the caution andwarning areas automatically to account for the closure rate and relativebearing of the intruder.

The perimeter of the caution area is 20 to 48 seconds from the time theintruder would penetrate the collision area. The perimeter of thewarning area is 15 to 35 seconds from the time the intruder wouldpenetrate the collision area. The time variations are based on logicparameters described in Section 5.

If an aircraft actually penetrates the caution area, TCAS designates itas an intruder and issues aTA. This advisory consists of both anaudiblewarninganda visual display indicating the distanceand relative bearingof the intruder to assist the crew’s visual search and identification of theintruding traffic.

NOTE: Avoidance maneuvers based solely on traffic advisories arenot recommended.


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If the intruder penetrates the warning area, TCAS issues an RA. RAsmay be either corrective or preventive. The visual display reacts in oneof the following ways:

D Changes to indicate a climb or descend advisory and recommendsa vertical rate (corrective).

D Cautions the crew not to make changes in the current vertical rate(preventive).

At the same time, an audible command is issued.

A more detailed explanation of the system logic parameters iscontained in Section 5.


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The collision, warning, and caution areas define a volume of spacearound the TCAS equipped aircraft, as shown in Figure 2--2. Theshape, horizontal, and vertical dimensions are a function of the rangeand closure rate of the intruding aircraft.

FAA TCAS II Caution and Warning AreasFigure 2--2


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TCAS ADVISORIES

TCAS generates RAs and TAs against intruder aircraft with ATCTransponders replying in Mode--S or Mode--C. The altitude informationincluded in these transmissions is used by the system in computingRAs. For intruder aircraft whose altitude reporting function isinoperative, TCAS can only generate TAs.

TAs andRAsareupdatedonceeach secondandgive real timeadvisoryand intruder position information to the crew. Theposition of the intruderis displayed on the VSI/TRA relative to the host aircraft to assist thecrew with a visual search so that the crew can “see and avoid” theintruder.

Once the system predicts that appropriate separation is attained,CLEAR OF CONFLICT is announced aurally to confirm that theencounter has ended. The flightcrew must return to the original ATCclearance profile.

TCAS II protection and services are shown in Figure 2--3.

1090 MHz ADS--B

ATCRBS (MODE--A)

MODE--SRADAR

SHIPS

TCAS I AND MODE--S

ATCRBS (MODE--C)

ATC MODE--SRECEIVER

ATC RECEIVER/TRANSMITTER

NON ICAORADAR

NON ICAOTRANSPONDER

ATC

TCAS II AND MODE--S

ICAOCOMPATIBLESYSTEMS

NON ICAOCOMPATIBLESYSTEMS

TAs

RAs

NO REPLYNO TAsNO RAs

NO REPLYRAMESSAGE

RAs

TCAS II AND MODE--S

COORDINATIONAND RAs

PASSIVETRACKDATA

ID--8000268

FAA TCAS II Protection and ServicesFigure 2--3


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Traffic Advisories

A TA is displayed 20 to 48 seconds from the time the intruder aircraftis predicted to enter the TCAS aircraft’s collision area. The actualdistance at the time of the advisory varies because of the intruder’sclosure rate and altitude. The TA is announced aurally by the wordsTRAFFIC, TRAFFIC. The traffic is displayed on the VSI/TRA as a solidamber circle (F) at the correct range and bearing relative to the TCASaircraft. An attached data tag displays the altitude separation inhundreds of feet. The data tag is displayed above the symbol if theintruder is above the TCAS aircraft and below the symbol if the intruderis below the TCAS aircraft. An up or down arrow is displayed next to thesymbol to indicate if the intruder’s rate of altitude change is greater than500 fpm.

CAUTION

THE DATA TAG ON THE DISPLAY SHOWS THE SEPARATIONBETWEEN AIRCRAFT IN HUNDREDS OF FEET.

Resolution Advisories

An RA is displayed 15 to 35 seconds from the time the intruder ispredicted to enter the TCAS aircraft’s collision area. The actualdistance at the time of the advisory varies because of the intruder’sclosure rate and altitude. Should an intruder enter the warning area, anRA is issued by the system. The RA is indicated on the VSI/TRA in theform of a prohibited red arc and a target green arc of vertical speed andis accompanied by an aural announcement. The intruder is displayedon the VSI/TRA as a solid red square (J) at the correct range andbearing relative to theTCASaircraft. Theattached data tag displays thesame information as in a TA. An RA is either a corrective RA or apreventive RA. A corrective RA calls for a change in vertical speed outof the red prohibited arc into the green target arc. A preventive RArestricts vertical speed to ensure separation and is indicated by a redarc only.

RAs may be intensified, weakened, or reversed, as appropriate, toresolve the conflict. Any alteration in an RA is accompanied by both anaural and a visual annunciator.

NOTE: Pilots are authorized to deviate from their current ATCclearance to the extent necessary to comply with TCAS RAswhen exercising emergency pilot authority. Pilots mustminimize the clearance deviation upon receipt of any RA.When CLEAR OF CONFLICT is annunciated, the pilot isexpected to return to the clearance profile.


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3. TCAS Controls and Displays

CONTROL PANEL

The TCAS function in T2CAS is controlled by a control panel in thecockpit. The aircraft has one of two types of TCAS/ATC transpondercontrol panels installed. TCAS requires a Mode--S Transponder tooperate. On aircraft with a single Mode--S Transponder, anATCRBS/Mode S/TCAS control panel (similar to Figure 3--1) isinstalled. On aircraft with two Mode--S Transponders, a dualMode--S/TCAS control panel (similar to Figure 3--2) is installed. Controlpanels produced by other suppliers may have additional functionssupported by enhancements in the TCAS computer.

ID--8000269

ATCCAS

XPDR FAIL

STBY

ATC

TCASTEST

MODE SON

TA

TA/RA

IDENT

ALT RPTGOFF

1 2

ON

TA DSPLYAUTO

OFF

25

6 4 3 7 1

ATCRBS/Mode--S/TCAS Control PanelFigure 3--1


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TCAS Controls and Displays3-2


ID--8000270

ATC1

XPNDR

6

1220 40

TRAFFIC

TA ONLY

TESTA

FAIL

RANGE

AUTO ON

12080

TC

ABV

N

BLW

IDENT

ALT SOURCE

1 2A

TC

S

STBY

ALT RPTGOFF

TA/RA

6

9 7

3 5 3 2

8 4 1

Dual Mode S/TCAS Control PanelFigure 3--2

1 TCAS/XPNDR (Transponder) Mode Selector

The control panel has a multiple--position switch to select thetransponder/TCASmode. Dependingon themodel of the control panel,this switchmay also include a TEST button for testing TCAS. Table 3--1describes the transponder and TCAS operating modes for each switchposition.


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Mode Selector Switch Position

TCASOperatingMode

Mode--STransponder

Operating Mode

STBY(Standby)

OFF OFF

ATC(Transponder Only)

OFF OFF(Selects ATCRBSTransponder ON)

ALTRPTG OFF(Altitude

Reporting Off)

OFF Mode--A

XPNDR(Transponder Only)

OFF Mode--SMode--CMode--A

MODE S ON(Transponder Only)

OFF Mode--SMode--CMode--A

TA or TA ONLY(Traffic

Advisories Only)

TrafficAdvisories

Only

Mode--SMode--CMode--A

TA/RA(Traffic Advisory/

ResolutionAdvisory)

TrafficAdvisories andResolutionAdvisories

Mode--SMode--CMode--A

NOTE: Depending on the model of the control panel, it may or may nothave all of the mode selector functions described above.

Mode--Selector Switch PositionsTable 3--1


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The mode--selector switch positions are described in detail in thefollowing paragraphs.

D TA/RA: The TA/RA mode is the normal TCAS operating mode. Inthis mode, TCAS generates both TAs and RAs. Also, in this switchposition, the Mode--S Transponder is selected for Mode--Soperation so the TCAS--compatible Mode--S Transponder must befunctional for the TA/RA mode to be valid.

D TA ONLY: In this position, TCAS generates TAs only; no RAs areissued. This mode prevents TCAS from issuing RAs when theTCAS aircraft is intentionally flying close to another aircraft, such ason a closely spaced parallel approach. Also, in this switch position,the Mode--S Transponder is selected for Mode--S operation, so theTCAS--compatible Mode--S Transponder must be functional for theTA ONLY mode to be valid. TA ONLY is annunciated on theVSI/TRA.

D XPNDR: The XPNDR position activates the Mode--S Transponderfunction only; TCAS is disabled and TCAS OFF is annunciated onthe VSI/TRA. The Mode--S Transponder operates in Mode--S.

D ALT RPTG OFF: This position turns the Mode--S Transponder’saltitude--reporting functions off. TCAS is disabled and TCAS OFFis annunciated on the VSI/TRA.

D STBY: In this position, the Mode--S Transponder is set to STBYmode and TCAS is disabled. TCAS OFF is annunciated on theVSI/TRA.

D TEST: Momentarily pushing the TEST button activates the TCASself--test feature. TCAS TEST is annunciated aurally (over thespeaker system). At the conclusion of the test, either TCAS PASSor TCAS FAIL is annunciated on the VSI/TRA and either TCASTEST PASS or TCAS TEST FAIL is annunciated aurally. Pushingand holding the TEST pushbutton for more than 8 seconds while theaircraft is on the ground, in STBY mode with altitude reportingselected ON, activates the extended test function.

NOTES: 1. In some installations, the self--test function may bedisabled during flight. Consult the aircraft’s ApprovedFlight Manual.

2. On the Mode--C/TCAS Mode--S Transponder, theTCAS TEST button is located separately from themode--selector switch, as shown in Figure 3--1.


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2 ALT SOURCE Switch

This two--position switch selects either non--corrected altitude source1 or non--corrected altitude source 2 as the pressure altitude signal forthe Mode--S Transponder.

3 Transponder Code Selector Knobs

Dual, concentric rotary knobs are used to enter ATC Mode--STransponder 4096 display codes. The large knobs control theoutermost digits (thousands and ones), and the small knobs control themiddle digits (hundreds and tens). Once a code limit is reached (0 or7), the display code will not change, even with continued knob rotationin the same direction. Transmitted data will not change untilapproximately 5 seconds after a new 4096 ATC code has beenselected.

4 Transponder Code Window

This window displays the selected 4--digit (“4096” code) Mode--STransponder code for ATC.

5 IDENT Button

Pushing this button initiates the Mode--S Transponder identificationmode of operation. The displayed ATC code and special positionidentification code are transmitted for a minimum of 18 seconds whenIDENT is pushed.

6 TRAFFIC Switch

This switch operates as follows:

D AUTO -- When TCAS is operating (that is, when the mode--selectorswitch is in the TA ONLY or TA/RA position) traffic is displayed onlywhen an intruder is identified, which results in a TA or an RA. Duringthis event, all RAs, TAs, and proximate traffic are displayed in orderto enhance situational awareness. Other traffic is not displayed.

D ON -- Displays all traffic at all times when the TCAS is operating(that is, when themode--selector switch is in the TAONLY or TA/RAposition). If a TA or an RA occurs, other traffic is removed from thedisplay during the event.


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7 ABV – N – BLW Switch

This switch selects the vertical range for which traffic is displayed.

D ABV (Above): Selects a range from +9,000 ft above the aircraft to–2,700 ft below the aircraft.

D N (Normal): Selects a range of +2,700 ft above the aircraft to–2,700 ft below the aircraft.

D BLW (Below): Selects a range of +2,700 ft above the aircraft to–9,000 ft below the aircraft.

NOTE: In some installations the ABV and BLW ranges may bedifferent. Consult the Approved Flight Manual.

8 XPNDR FAIL Annunciator Light

TheamberXPNDRFAIL light indicates when theMode--STranspondersystem has failed. The XPNDR FAIL light turns on under any of thefollowing conditions:

D Internal Mode--S Transponder failure

D Control panel failure

D Loss of valid altitude data from the barometric altimeter to theMode--S Transponder

D Dual antenna failure in any mode

D Top or bottom antenna failure in RA/TA mode.

Any condition that lights the amber XPNDR FAIL annunciator alsocauses TCAS to display TCAS OFF on the VSI/TRA.

9 RANGE Switch

The RANGE switch selects the scale used for display of traffic on theVSI/TRA. Typical selections are 6, 12, 20, 40, 80, or 120 NMdependingon the capability of the display and controller. Consult the ApprovedFlight Manual.


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DISPLAY

There are three possible display installations. How TCAS symbols aredisplayed depends upon the type of installation. A flat--panel VSI/TRAindicator installation shows both traffic and vertical speed informationon the indicator. An EFIS installation displays traffic on the navigationdisplay (ND) and vertical speed information forRAs on the primary flightdisplay (PFD) VSI tape. A third application includes a dedicated trafficdisplay using a modified weather indicator. Differences in theoperations do exist depending on the manufacturer. Appendix Ddescribes TCAS symbols on theNDandPFD for different EFIS aircraft.

VSI/TRA Display

A color flat--panel liquid crystal display (shown in Figure 3--3) replacesthe conventional VSI. This display has two modes of operation: as anormal VSI and as a TRA display. As a VSI, the indicator gives astandard display of vertical speed in feet per minute (fpm) with a rangeof plus and minus 6,000 fpm. As a TRA display, an aircraft symbolrepresenting the TCAS aircraft is displayed in the lower part of thedisplay surrounded by 12 white dots. The dots are located at the clockpositions to assist the crew in visually acquiring the traffic.

Flat Panel VSI/TRA IndicatorFigure 3--3


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The data displayed on the VSI/TRA depends on several switch settingsas well as the specific status of the intruder as shown in Table 3--2. Inaddition to the switch settings shown in the table, other factors caninfluence the display logic. These factors include the specific model ofcontrol panel certified for the installation, the manufacturer of theVSI/TRA, and theTCASwiring options selected. All of these factors aredetermined at the time the TCAS system is certified. The operationallogic described in the Table 3--2 describes the most common systemconfiguration. For information regarding TCAS operation for a specificaircraft, consult the Approved Flight Manual.

TRAFFICSwitch

SelectedTCASMode

IntruderStatus

DisplayFormat

DisplayedTraffic

TA ONLYOR TA/RA

TA or RA VSI/TRATA,

RA, andProximate

OR TA/RAProximate,Other or VSI None

AUTOOther, orNone

VSI None

STBY,ALT RPTGOFF, orXPNDR

TA,RA,Proximate,Other, orNone

VSI None

ON

TA ONLYOR TA/RA

TA,RA,Proximate,Other, orNone

VSI/TRAAll

(refer tonote)

ONSTBY,ALT RPTGOFF, orXPNDR

TA, RA,Proximate,Other, orNone

VSI None

NOTE: All traffic is displayed unless a TA or an RA is in progress. In this case,other traffic is not displayed.

Typical Display Formats and FunctionsTable 3--2


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Table 3--3 lists the range indicators of the VSI/TRA for each of theRANGEswitch settings. Figure 3--4 shows the rangemeasurements onthe VIS/TRA display panel.

Color--coded symbols are used on the display to indicate traffic near theaircraft.

RANGESetting Ring of Dots

Forward(100% ofRANGESetting)

Left or Right(70% ofRANGESetting)

Aft(42% ofRANGESetting)

6 2 NM 6 NM 4.2 NM 2.5 NM

12 2 NM 12 NM 8.3 NM 5.0 NM

40 —(See Note)

40 NM 28 NM 17 NM

NOTE: When RANGE is set to 40 NM or greater, the ring of white dots is removedfrom the VSI/TRA display.

VIS/TRA Range SettingsTable 3--3

2 NM(3.7 KM)

4.2 NM(7.7 KM)

4.2 NM(7.7 KM)

2.5 NM(4.7 KM)

6 NM(11 KM)

ID--8000272

VSI/TRA Range MeasurementsFigure 3--4


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Primary Flight and Navigation Displays

TCAS information displayed on the electronic PFDs and NDs is similarto that in combinedVSI/TRA indicator equippedaircraft. Symbols, auralalerts and pilot action are identical. However, it is necessary torecognize that vertical speed information for RAs is displayed as green“fly to” or red “avoid” areas on the PFD’s VSI tape. TCAS traffic, on theother hand, is displayed on the ND. TCAS traffic display on the NDvaries with manufacturer (refer to Appendix D). The Boeing electronicinstrument system’s (EIS) PFDsandNDsare shown inFigures 3--5 and3--6. Some Boeing installations also give pitch guidance. When an RAor TA occurs and the ND range is greater than 40 NM, the pilot isprompted to reduce range on the ND.

ID--8000273

Boeing EIS PFD – Climb RA ShownFigure 3--5


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ID--8000274

Boeing EIS ND – TCAS ModeFigure 3--6


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Modified Weather Indicator

Figure 3--7 shows an example of a dedicated traffic display using amodified weather indicator.

ID--8000275

BELOW

NORM

ABOVE

5 10 20 40TCASAUTO BRT

RNG 10

TEST

+10

--10

--02

+02

Modified Weather IndicatorFigure 3--7


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RESOLUTION ADVISORY VERTICAL SPEEDGUIDANCE

Vertical maneuvers recommended by TCAS to ensure safe separationare displayed as red and green arcs, as shown in Figure 3--8.

The TCAS color--coded visual advisory area for vertical speedguidance is inside, and adjacent to, the vertical speed indicator scale.The red arc indicator tells the pilot what vertical speed region is to beavoided. If a change in vertical speed is necessary, the specific regionof vertical speed the pilot is to “fly to” is indicated by a green arc.

ID--8000276

RED PROHIBITEDVERTICAL SPEED(NARROW ARC)

GREEN TARGETVERTICAL SPEED

(WIDE ARC)

VSI/TRA Command IndicatorsFigure 3--8


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TRAFFIC DISPLAY SYMBOLS

Aircraft symbols displayedon theVSI/TRAare color--coded. Each colorhas a distinct shape associated with it. Data tags have the same coloras the symbol they are associated with. Intruders are prioritized anddisplayed based on their measured range and relative range rate withrespect to the TCAS aircraft. The VSI/TRA can display a maximum of12 aircraft. The highest priority is given to RAs. The remaining TAs (ifpresent) and proximate traffic (if present) are displayed according totheir calculated threat assessment based on range, range rate, andwhether the intruder has altitude reporting capability.

The displayed traffic is positioned at its correct range and relativebearing andmoves across the display as its range and bearing change.

Solid Red Square

A solid red square (J) represents an immediate threat to the TCASequipped aircraft. Prompt actionmust be taken to avoid the intruder. Anintruder symbolized in red is entering the warning area and is 15 to 35seconds from entering the collision area. Red is used only inconjunction with an RA.

Solid Amber Circle

A solid amber circle (F) represents a moderate threat. An intrudersymbolized in amber is entering the caution area and is 20 to 48seconds from entering the collision area. A visual search isrecommended for intruder avoidance. Amber is used only inconjunction with a TA.

Solid Blue Diamond

Asolid blue (cyan) diamond (z) represents proximate traffic. Proximatetraffic is an aircraft which is within 6 NM and within 1,200 ft vertically,but whose path is not predicted to penetrate the collision area. If therange capability of the display is less than 6 NM then the proximatetraffic is shown at the edge of the display. Proximate traffic does notgenerate a TA or an RA. Proximate traffic is shown to improvesituational awareness in the event of a potential conflict with higherpriority RA or TA aircraft.

NOTE: Somemanufacturer’s displays may indicate proximate trafficwith a solid white diamond.


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Open or Hollow Blue Diamond

An open or hollow blue (cyan) diamond (Z) represents other traffic.Other traffic is any transponder--replying aircraft within the horizontaland vertical range of the display, and not classified as proximate trafficor as an intruder requiring a TA or an RA. The predicted flight path doesnot penetrate the collision area. If other traffic is being displayed, it istemporarily removed while a TA or an RA is in progress.

NOTE: Somemanufacturer’s displays may indicate proximate trafficwith a solid white diamond.

Data Tags

A data tag consists of a two--digit number, a plus or minus sign, andpossibly an arrow. The data tag is displayed either above or below theintruder aircraft symbol and in the same color. When the intruder is atthe same altitude, 00 is displayed. If the number changes position, fromabove the aircraft symbol to below or vice versa, the intruder is passingthrough the aircraft’s current altitude. The elements of the data tag are:

D Two--Digit Number -- The two digits represent the relative altitudeof the intruder aircraft in hundreds of feet above or below the TCASaircraft. If the intruder is above the TCAS aircraft, the data tag isdisplayed above the intruder aircraft symbol, for an intruder belowthe TCAS aircraft, the data tag is displayed below the intruderaircraft symbol.

CAUTION

THE DATA TAG ON THE DISPLAY SHOWS THE SEPARATIONBETWEEN AIRCRAFT IN HUNDREDS OF FEET.

D Plus and Minus Signs -- A plus or minus sign is displayed in frontof the relative altitude number and indicates whether the displayedaircraft is above (+) or below (–) the TCAS aircraft.

D Arrow -- A vertical arrow is displayed immediately to the right of theaircraft symbol if the intruder is either climbing (up arrow) ordescending (down arrow) in excess of 500 fpm.

D Flight ID Data Tag -- If the flight ID (identification) feature of TCASis enabled, and a tracked intruder that is being displayed is also“squittering” its flight ID, the flight ID of that intruder is displayednextto the intruder aircraft symbol. When an RA is in progress all flightID information may be removed depending on the displaycharacteristics.


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Off Scale Traffic Advisories

If TCAS is tracking an intruder which is outside of the range of thedisplay but within the caution or warning areas, one--half of theappropriate symbol is positioned at the edge of the display at theappropriate bearing. The data tag is displayed if there is room. Thesymbol is its proper color.

CAUTION

AN OFF--SCALE INTRUDER THAT GENERATES A TA OR AN RAPROBABLY HAS A HIGH CLOSURE RATE.

No Bearing Advisories

If and when TCAS is unable to track the bearing of an intruder, the TAis displayed in the lower center of the display just below the host aircraftsymbol. The advisory has the appropriate color--coded trafficinformation. TCASmay be temporarily unable to determine the bearingof an intruder due to steep bank angles masking the directionalantenna. A no bearing advisory is most likely the result of the antennapattern coupled with a steep bank angle. The ability of TCAS tocompute TAs and RAs is not degraded by lack of bearing informationand usually a no bearing advisory changes to an advisory with bearingafter a few seconds.


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EXAMPLE OF VSI/TRA WITH TRAFFIC DISPLAYED

In the VSI/TRA example shown in Figure 3--9, the RANGE is set at6 NM.

PROXIMATETRAFFIC

TRAFFICADVISORY

ID--8000277

RESOLUTIONADVISORY

OTHERTRAFFIC

NO BEARINGINTRUDER

Indicators and SymbolsFigure 3--9

The items shown in Figure 3--9 are described in the followingparagraphs.

D Traffic Advisory -- The TA intruder is off scale at 10:30, 200 ft belowthe TCAS aircraft, and climbing in excess of 500 fpm.

D Proximate Traffic -- There is proximate traffic at 1:00, 1,100 ftbelow, and about 5.5 NM away. The traffic is either in level flight oris climbing or descending at less than 500 fpm.

D Resolution Advisory -- The RA intruder is at 12:30 with respect tothe host aircraft, just over 2 NM away, 300 ft below the TCASaircraft, and descending at more than 500 fpm. TCAS has issuedanRA instructing a minimum climb rate of 1,500 fpm.

D Other Traffic -- There is other traffic at 3:30, about 4 NM away,1,700 ft above, and descending in excess of 500 fpm.

NOTE: While a TA or an RA is in progress, other traffic is notnormally displayed. It is shown here only to illustrate thesymbols.


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D No Bearing Intruder -- The no bearing intruder is 2 NM distant,300 ft above the TCAS aircraft.

NOTE: It is unlikely that a no bearing intruder would be displayed.It is shown in this example only to illustrate how theintruder would be displayed. Remember that the ability ofTCAS to compute a TA or an RA is not degraded by lackof bearing information.

AURAL MESSAGES

TCAS generates 14 aural alerts or messages, excluding the aural testmessages that are announced over the cockpit loudspeaker system.These 14 messages accompany the visual TA and RA displays.

If a logic changeoccurs before themessage is complete andanewalertis initiated, the original alert is terminated and the new alert isannounced immediately. Volume is preset and cannot be adjusted bythe crew.

Traffic Advisory

TRAFFIC – TRAFFIC

This alert occurs when TCAS predicts an intruder will enter the collisionarea within 20 to 48 seconds. Simultaneously, the VSI/TRA will displaythe location of the intruder.


RA messages come in two forms. Corrective advisories indicateevasive vertical maneuvers are necessary to increase separationbetween the TCAS aircraft and the intruder. Preventive advisories thatindicate certain changes in vertical speed are not recommended. RAmessages consisting of a single word are repeated two times. Longermessages may be repeated twice.

Preventive or Weakening Advisory

MONITOR VERTICAL SPEED

This advisory is a preventive advisory. The pilot is tomonitor the verticalspeed of the aircraft, keeping the VSI pointer out of the red area on theVSI scale. The pilot is further expected to minimize the deviation fromATC clearance to reduce further adverse effects on ATC.


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Corrective Resolution Advisories

Once these commands are given, the pilot has 5 seconds to make thecontrolled 0.25 g pitch change required. These advisories should bedone smoothly to minimize the amount of deviation from the ATCclearance.

CLIMB – CLIMB

Climb at the rate indicated by the green arc on the VSI/TRA, 1,500 to2,000 fpm.

DESCEND – DESCEND

Descend at the rate indicated by the green arc on the VSI/TRA, 1,500to 2,000 fpm.

CLIMB, CROSSING CLIMB – CLIMB, CROSSING CLIMB

Climb at the rate indicated by the green arc on the VSI/TRA, 1,500 to2,000 fpm.

NOTE: This aircraft’s flight path will cross the intruder’s altitude.

DESCEND, CROSSING DESCEND – DESCEND, CROSSINGDESCEND

Descend at the rate indicated by the green arc on the VSI/TRA, 1,500to 2,000 fpm.

NOTE: This aircraft’s flight path will cross the intruder’s altitude.


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Increased Strength or Reversed CorrectiveAdvisories

These are corrective advisories that indicate when a previouslyannounced advisory must be increased in strength or reversed. Thetarget vertical speed must be attained within 2.5 seconds of thegeneration of the corrective RA. The 0.35 g maneuver should be a 2 to3.5 degree per second pitch change, as smooth and precise as anyinstrument maneuver.

These advisories are expected to occur only on rare occasions, usuallywhen an intruder suddenly changes its current flight path bymaneuvering or when the pilot has chosen to ignore acorrective/preventative advisory.

INCREASE CLIMB – INCREASE CLIMB

Increase climb to the rate indicated by the green arc on the VSI/TRA,2,500 to 3,000 fpm.

INCREASE DESCENT – INCREASE DESCENT

Increase descent to the rate indicatedby thegreen arc on theVSI/TRA,2,500 to 3,000 fpm.

CLIMB, CLIMB NOW! – CLIMB, CLIMB NOW!

Follows a descend RA when TCAS has determined that a reversal ofvertical speed is necessary to give adequate separation. The targetvertical speed for this green arc climb is 1,500 to 2,000 fpm.

DESCEND, DESCEND NOW! – DESCEND, DESCEND NOW!

Follows a climb RA when TCAS has determined that a reversal ofvertical speed is necessary to give adequate separation. The targetvertical speed for this green arc descent is 1,500 to 2,000 fpm.


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Corrective, Weakening, or Restrictive Advisories

These corrective advisories include a variety of vertical speedcommands and guidance intended tominimize or constrain the escapemaneuvers or resolve multiple aircraft conflicts in response to an RA.

ADJUST VERTICAL SPEED, ADJUST

For this advisory, the target vertical speed for the green arc is areduction in the current vertical speed.

MAINTAIN VERTICAL SPEED, MAINTAIN

Theaircraft’s current vertical speed is greater than 1500 feet perminuteclimbing or less than --1500 feet per minute, descending. The targetvertical speed for this command is the aircraft’s current vertical speed.A green band to indicate that you should remain at the current verticalspeed will appear on the VSI.

MAINTAIN VERTICAL SPEED, CROSSING MAINTAIN

Theaircraft’s current vertical speed is greater than 1500 feet perminuteclimbing or less than --1500 feet per minute, descending. The targetvertical speed for this command is the aircraft’s current vertical speed.A green band to indicate that you should remain at the current verticalspeed will appear on the VSI.

NOTE: For this advisory, TCAScalculates the aircraft’s flight pathwillcross the intruder’s altitude.

Clear of Conflict

CLEAR OF CONFLICT

This single announcement confirms the encounter has ended andseparation is increasing. A return to the original ATC clearance profileis expected.


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TCAS Annunciators


4. TCAS Annunciators

The VSI/TRA display gives visual mode and failure annunciators in theupper left and upper right corners, and in the center of the display.

MODE ANNUNCIATORS

ThemessageTAONLY is displayed in whitewhen theTraffic Alert Onlymode is selected. This message is also displayed when RAs areinhibited due to a terrain or ground proximity alert, a windshear alert, orwhen the aircraft is at altitudes less than 1,000 ft (+/-- 100 ft, hysteresis)AGL. The message is displayed in the upper left corner of the display,as shown in Figure 4--1.

ID--8000278

TA ONLY AnnunciatorFigure 4--1


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TCAS Annunciators4-2


The message TCAS OFF is displayed when the mode--selector on thecontrol panel is set toXPNDR, STBY, or ALTRPTGOFF. Thismessageis also displayed if the Mode--S Transponder fails. The message isdisplayed in the right center of the display, as shown in Figure 4--2.

NOTE: Also, TCAS OFF is displayed when one of the two Mode--STransponder antennas fails. Pilot selection of the TA ONLYmode removes the TCAS OFF message and returns TAONLY capability to the TCAS system thereby providingsituational awareness.

ID--8000279

TCAS OFF AnnunciatorFigure 4--2


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TCAS Annunciators


FAILURE ANNUNCIATORS

If an in--flight failure of the minimum equipment required for TCASoperation occurs, TCAS FAIL is displayed in the right center of thedisplay, as shown in Figure 4--3.

ID--8000280

TCAS FAIL IndicatorFigure 4--3

RA FAIL (resolution advisory failure) is displayed in the upper leftcorner when TCAS cannot display RAs, as shown in Figure 4--4.

ID--8000281

RA FAIL IndicatorFigure 4--4


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TD FAIL (traffic display failure) is displayed in the right center of thedisplay when TCAS cannot display TAs, as shown in Figure 4--5.

ID--8000282

TD FAIL IndicatorFigure 4--5

Failure or loss of valid vertical speed data input prevents display of RAinformation.RAFAIL andVSI FAIL (vertical speed indicator failure) areannunciated on the indicator in the upper left and upper right cornersrespectively and the VSI pointer is not displayed, as shown inFigure 4--6.

ID--8000283

VSI FAIL and RA FAIL IndicatorFigure 4--6


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TCAS Annunciators


In the case of certain failures of the VSI/TRA display itself, an X maymay be displayed, as shown in Figure 4--7. A two--digit code located atthe bottom center is used for maintenance information. In other casesthe display may be blank with neither vertical speed nor TA displaysvisible.

ID--8000284

Red X DisplayFigure 4--7


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SELF--TEST ANNUNCIATORS

Pushing and releasing the TEST button activates the 8--second TCASself--test feature. During the test, the TCASCU, Mode--S Transponder,control panel, displays, and aural advisory systems are tested.

Figure 4--8 shows the self--test displays. The tests begin with the auralmessage “TCAS TEST”. The VSI/TRA display shows a standard testpattern of intruders and RA arcs along with the annunciator, TCASTEST (in white), in the upper left corner of the display. The trafficsymbols displayed during the test are an RA, a TA, a proximate traffic,and an other traffic. At the completion of the self--test, the auralmessage, “TCASTESTPASS”or “TCASTESTFAIL”, togetherwith thevisual display, TCAS PASS or TCAS FAIL indicates system status.

ID--8000285

TCAS Self--Test Annunciator on VSI/TRA DisplayFigure 4--8


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TCAS Annunciators


If the TEST button is pushed and held for more than eight (8) secondswith the mode selector switch set to STBY, altitude reporting selectedon, and the aircraft is on the ground with weight--on--wheels, the testpattern is replaced with maintenance information (see Figure 4--9). Ifthis extended test mode is accidentally entered, it can be exited byplacing themodeselector switch to any position other than STBY.Referto the current T2CAS System Description and Installation Manual formore information.

NOTE: In some installations the self--test function may be disabledduring flight. Consult the aircraft’s Approved Flight Manual.

ID--8000311

Extended Test Display – Main MenuFigure 4--9


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5. TCAS Logic Parameters

This section describes the logic parameters used to determine thecaution, warning, and collision areas. Figure 5--1 shows the variousaltitudes that establish the thresholds and sensitivities used inTCAS calculations. The figure also shows the inhibits which are builtinto the system at low altitudes that prevent inappropriate RAcommands. Table 5--1 shows the specific numbers associated with thevarious altitude layers and sensitivity levels (SL). The paragraphs thatfollow further describe the variables and their meanings. Many specialconditions are beyond the scope of this manual. A complete descriptionof TCAS logic can be found in the document, “TCAS II MinimumOperational Performance Standards (MOPS) DO--185A” published byRadio Technical Commission for Aeronautics (RTCA), Inc.

The TCAS function in T2CAS is compatible with reduced verticalseparation minimums (RVSM). Aircraft separated by greater than850 ft belowFL420, or by greater than1,200 ft aboveFL420, andwhichare within the TCAS coverage range, will not generate a TA.


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TCAS Logic Parameters5-2


TCAS Sensitivity Levels and Altitude LayersFigure 5--1


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Sensitivity Level(SL) 1 2 3 4 5 6 7

RA Alarm Time(seconds)

— — 15 20 25 30 35

TA Alarm Time(seconds)

— 20 25 30 40 45 48

Protected Area(nautical miles)

— — 0.20 0.35 0.55 0.80 1.1

Altitude Layer (feet) 1 2 3 4 5 6

TA Vertical Threshold (feet) 850 850 850 850 850 1200

Preventive RA Threshold(feet)

600 600 600 600 700 800

Positive RA Vertical Threshold(feet)

300 300 350 400 600 700

TCAS 2000 Logic Parameter ValuesTable 5--1

SENSITIVITY LEVEL

TCAS uses anSL to determine the alarm time, the size of the protectedarea, and the vertical threshold for TAs and RAs. The range of the SLis from 1 to 7. For higher SLs, the size of the protected area is largersince the traffic density is lower so more protection canbe given.WhenTCAS is in STBY mode, the SL is one (1).

TCAS determines the SL by the altitude of the host aircraft. For SL 2and SL 3, radio altitude is used, and for SL 4 through SL 7, pressurealtitude is used. When radio altitude and pressure altitude implydifferent SLs, TCAS uses the lower SL. Therefore, when within therange of valid radio altitude, the radio altitude signal is used todetermine SL; otherwise, pressure altitude is used.


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TCAS Logic Parameters5-4


PROTECTED AREA

The horizontal extent of the protected area is defined by the time toclosest point of approach (CPA). Therefore, the size of the area isdependent upon the speed and track of the threat aircraft and the SL.However, if the rate of closure is very slow, a threat could getdangerously close without generating a TA or an RA. For this reason,the boundaries of the protected area are modified at close range. Theprotected area value listed in Table 5--1 is added to the intruder’sdistance when determining the CPA. If an intruder aircraft penetratesthe protected area, an RA is generated regardless of the closure rate.The higher the SL, the larger the protected area. When an RA isproperly flown, the miss distance may be as small as 300 to 700 ft.

NOTE: In this Pilot’s Guide, CPA refers to “closest point of approach”in the context of TCAS operation, and “collision predictionand alerting” in the context of TAWS operation.

VERTICAL THRESHOLD

This is theprotected vertical distance used for determining if an intruderis a threat. There are different vertical distances for TAs, preventativeRAs, and corrective RAs. A preventative RA requires the pilot tomonitor and maintain the vertical speed within a specified range. Acorrective RA requires a change in climb or descent rate by the TCASaircraft. TCAS always uses the pressure altitude in its determination ofvertical threshold. The higher the SL, the larger the vertical thresholdand collision area.

ALARM TIME

The alarm time is the time it will take the TCAS aircraft and threataircraft to reach the CPA. A combination of the protected area and thevertical threshold are used to determine the CPA. The higher the SL,the earlier an alert is annunciated.

EXAMPLE CALCULATIONS

Table 5--1 is used in conjunction with Figure 5--1. For example, if anaircraft is flying at 18,000 ft above mean sea level (MSL), Figure 5--1indicates that it is in SL 6 and altitude layer 4. From Table 5--1, the RAalarm time is 30 seconds, the TA alarm time is 45 seconds, and thecollision area is increased by 0.8 NM. A TA is triggered whenever anintruder is predicted to come within 850 ft vertically. An RA is triggeredif the intruder is predicted to come within 600 ft vertically. Finally, thepilot is directed to change vertical speed when the intruder is predictedto come within 400 ft vertically.


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Flightcrew Response to TCAS Advisories


6. Flightcrew Response to TCASAdvisories

PILOT RESPONSIBILITIES

For TCAS to work effectively, timely, and reliably, crew response toTCAS advisories is essential. Delayed crew responses or reluctance ofa flightcrew to adjust their flight path as advised by TCAS due to ATCclearance provisions, fear of later scrutiny by authorities, or otherfactors, significantly decrease or negate the protection afforded byTCAS.

The aviation industry, including both regulatory agencies and airlines,has developed a series of guidelines based on the equipmentcertification requirements, industry meetings, experiences during theFAA TCAS Transition Program, etc. Non-compliance with theseguidelines produces less than desired separation. flightcrewsoperating in United States airspace are expected to respond to TCASin accordance with the following guidelines. flightcrews operating inother country’s airspace are expected to familiarize themselves withany special rules thatmay be in effect relating toTCAS operationspriorto entering that airspace using TCAS.

Traffic Advisories

Respond immediately to TAs by attempting to establish visualcontact with the intruder aircraft and other aircraft that may be in thevicinity. Coordinate to the degree possible with other flightcrewmembers to assist in searching for traffic. The pilot must not initiateevasive maneuvers using information from the traffic display only, orupon receipt of a TA only, without positive visual identification of thetraffic. These TA displays and advisories are intended only forassistance in visually locating the traffic; TAs lack the flight path trendsnecessary for use in evasive maneuvering. However, while climbing ordescending, modest changes in vertical speed based on traffic displayinformation are not considered evasive maneuvering.

The pilot must reduce vertical speed to 1,500 fpm or less when within2,000 ft of an ATC directed level off altitude to reduce the incidence ofunnecessary RAs. If traffic is acquired visually, continue to maintain orattain safe separation in accordancewith good operating practices andcurrent United States Federal Aviation Regulations (FARs) or otherapplicable air regulations.


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Flightcrew Response to TCAS Advisories6-2



Compliancewith TCASRAs is necessary and authorized. According toUnited States FAR91.123, pilots are authorized to deviate from anATCclearance if “the deviation is in response to a traffic alert and collisionavoidance systemRA.” Respond immediately to satisfy corrective RAsusing positive control inputs, in the direction and with the magnitudeTCAS advises, while attempting to sight the conflicting traffic. Theaircraft’s vertical speed indicator as shown on the VSI/TRA must bemoved out of the red band and into the green band.

For TCAS to properly function, initial vertical speed response isexpected within five seconds of an RA. Maneuvering g--forces must besimilar to those felt when responding to an ATC clearance to climb ordescend “immediately” (0.25 g increment). If possible, visually confirmthe necessity and suitability of the avoidance maneuver but recognizethat any other aircraft seen visually may not necessarily be the threataircraft or the only aircraft that is triggering the TCAS system response.

CAUTIONS

1. MANEUVERING IN RESPONSE TO RAs MUST BE DONEMANUALLY BY THE PILOT FLYING THE AIRCRAFT.AUTOPILOT RESPONSE TIME MAY BE TOO SLOW TO GIVETHE DESIRED SEPARATION. PILOTS MUST DISCONNECTTHE AUTOPILOT AND ESTABLISH THE PROPER PITCHATTITUDE MANUALLY.

2. ONCE A NON-CROSSING RA HAS BEEN ISSUED, SAFESEPARATION COULD BE COMPROMISED IF CURRENTVERTICAL SPEED DIRECTION IS CHANGED, EXCEPT ASNECESSARY TO COMPLY WITH THE RA. THIS IS BECAUSETCAS--TO--TCAS COORDINATION WITH THE INTRUDERAIRPLANE MAY BE IN PROGRESS AND ANY CHANGE INVERTICAL SPEED THAT DOES NOT COMPLY WITH THE RAMAY NEGATE THE EFFECTIVENESS OF THE OTHERAIRCRAFT’S COMPLIANCE WITH THE RA.


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Prioritization of Actions

Whenmore thanonealert is in cue for pilot response, thepilot must takethat action that assures the most favorable and safest outcome. Forexample: if a TCAS RA is interrupted by a terrain or ground proximityalert or a stall warning, the pilot must use appropriate judgement.

D Respond immediately to the RA display to satisfy or continue tosatisfy RA vertical speed constraints by keeping vertical speed outof the red arc and minimizing altitude excursions during the RA asmuchas possible. This includes softening,weakening, or reductionsin strength of the initial RA. Also, attempt tomake visual contact withthe conflicting traffic. After the “CLEAR OF CONFLICT”announcement, adhere to the current ATC clearance to the extentpossible.

D Respond immediately to any increase or reversal RA maneuveradvisories. Initial vertical speed response to an increase or reversalRA is expected by TCAS within two and one--half seconds of theissuance of the advisory. These increase or reversal RAmaneuversmust be responded to with a 0.35 g maneuver; more is not requiredor desired – less is insufficient.

D Excessive responses to TCAS RAs are not desirable or appropriatebecause of other potential traffic and ATC consequences. Fromlevel flight, proper response to a TCAS RA typically results in anoverall altitude deviation of 300 to 700 ft in order to successfullyresolve a traffic conflict. Minimize deviations from the ATCclearance profile when practical.

D If a TCAS RA requires maneuvering contrary to an ATC clearance,satisfy the RA in a way that most nearly complies with the ATCclearance. If it is possible to both respond to a TCAS RA andcontinue to satisfy a clearance at the same time, the pilot can do so.For example, the pilot can respond to a climb RA while continuingto satisfy an ATC clearance to intercept a localizer.

If a TCAS RA maneuver is inconsistent with the current ATCclearance, the pilot:

— Must not delay in responding to the RA

— Must not modify a response to an RA

— Must follow the RAmaneuver, unless invoking “Emergency PilotAuthority”

— Must give a vertical rate that minimizes ATC deviations.


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D During all RA events, notify ATC of the encounter as soon aspractical.

D Following a TCAS “CLEAROF CONFLICT” advisory, the pilot mustexpeditiously return to the applicable ATC clearance unlessotherwise directed, and notify ATC.

D If a TCAS RA requires maneuvering contrary to right--of--way rules,cloud clearance rules while operating in visual flight rules (VFR),flight handbook limitations, or other such criteria, pilots may, andare expected to, follow the TCAS RA to resolve the immediatetraffic conflict. In such situations, however, deviations from rules,policies, or limitationsmust bekept to theminimumnecessaryto satisfy the RA. For example, an RA response resulting in a minorexcursion above the Approved Flight Manual published maximumaltitude is considered acceptable.

D The pilot must not exceed stick shaker or other stall warnings orprotections when following an RA.

D When a climb RA occurs with the aircraft in the landingconfiguration, the pilot must initiate a normal go--around (GA)procedure in order to comply properly with the RA.

NOTES: 1. A climb RA does not mandate a missed approach.The pilot must exercise appropriate judgment toassure the airplane is properly configured for themaneuver, whether it be a subsequent landing or ago--around/missed approach. In most cases, theTCAS event can be resolved with only a minordeviation to the intended flight path and sufficienttime and altitude exists to recover safely to thedesired flight path.

2. Analtitude--crossingmaneuver canoccurwhen theintruder or host aircraft is climbing or descending ata high rate. Under these conditions, the TCAS logicdetermines that safe separation is best achievedthrough an altitude--crossing maneuver. Thismaneuver results in the TCAS aircraft and theintruder crossing through each other’s altitude.This safe strategy results in adequate verticalseparation between aircraft.


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When a TCAS equipped aircraft follows an RA in a coordinated conflictresolutionmaneuver with another TCAS equipped aircraft, or during anevent with an unequipped or non--functioning TCAS aircraft involvinga crossing maneuver, the change in vertical speed may be noticeable.Many altitude--crossing RAs can be avoided by reducing climb ordescent vertical speed to 1,500 fpm when within the last 2,000 ft priorto reachinga level off altitude. Optional integration of an altitudealertingsystem or flight control unit/mode control panel (FCU/MCP) selectedaltitude with the TCAS gives intent information that further enhancesthe TCAS system and may resolve many potential events.

EXPECTED FLIGHTCREW RESPONSE

TCAS is programmed with 14 aural announcements (excluding testannouncements). These 14 announcements alert the crew to changingtraffic conditions. The aural announcement, TRAFFIC, TRAFFIC isgenerated when a potential traffic threat is approaching. A variety ofaural alerts are givenwhen the first RA of an encounter is displayedandeach time a subsequent change in the advisory is displayed(strengthened or weakened). The announcements differentiate theadvisories by type. The softened or weakened advisory MONITORVERTICAL SPEED is initiated to facilitate minimizing the verticaldeviation from ATC clearances. An aural announcement also indicatesthe TCAS aircraft is CLEAR OF CONFLICT. This announcementoccurs when the RA is removed from the VSI/TRA display and theconflicting aircraft has begun to diverge in range.

In normal instrument flight operations, the vertical speed is the flightinstrument that validates the performance initiated on the attitudeindicator. Therefore, if a specific vertical speed is desired, apredetermined pitch change is made on the attitude indicator, and thenthe performance is verified on the VSI.

Flying an RA with precision (an instrument maneuver) requireschanging the pitch of the aircraft with a known performance effect. Forsmall changes in pitch, the following approximate relationships existbetween Mach, pitch change, and vertical speed.

(Mach No.) X 1,000 = Vertical Speed change in feet per minute fora 1 pitch change.

A prompt, smooth pitch changeof 2 to 6 should be sufficient to resolvenearly all conflicts.


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COCKPIT RESOURCE MANAGEMENT

When flightcrews have special training in cockpit coordination orcockpit resource management (CRM) techniques that analyze andidentify specific tasks for each member of the flightcrew under variousconditions, safety is enhanced. An example of the results of such ananalysis and the resulting tasks for the pilot flying (PF) the aircraft andthe pilot not flying (PNF) the aircraft are shown below. Airlines and flightoperations departments are encouraged to establish CRM proceduresfor each TCAS message based on their own flight manuals andoperating practices. The example that follows is one outcome of suchan analysis. Alternative procedures and responsibilities are alsopossible.

D 20 to 48 seconds prior to the CPA, the following TA alert isannounced:

TRAFFIC – TRAFFIC

— PF: Scans outside the aircraft for traffic, focusing in the directionadvised by the PNF.

— PNF: Calls out the intruder’s clock position (relative bearing),relative altitude, and distance and joins the PF in the visual scanfor traffic. Updates thePF from the clues inside the cockpit as theencounter proceeds.

D If the event continues to develop, 15 to 35 seconds prior to the CPAan RA alert is announced.

CLIMB – CLIMB (or other command)

— PF: Looks inside the aircraft to determine the commandedvertical speed required and changes the pitch of the aircraft onthe attitude indicator to the computed target attitude which willyield the commanded vertical speed.

— PNF:Continues to scan outside the aircraft for traffic, backs upthe PF to ensure required performance, and notifies ATC whenpractical.

D As the event continues and the corrective action proves effective,the RA will probably weaken, and a preventive or weakeningadvisory will be annunciated.

ADJUST VERTICAL SPEED, ADJUST

— PF: Follows the new TCAS displayed and directed verticalspeed, which may include a softening of the maneuver or allowa decrease in the vertical maneuver performance to minimizedeviation from the ATC clearance.


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— PNF: Backs up the PF and ensures the performance is withinthat prescribed.

NOTE: TCAS gives 300 to 700 ft of separation betweenaircraft at the CPA.

D When aircraft separation has increased and the event is ended, theconcluding announcement is made.

CLEAR OF CONFLICT

— PF: Smoothly and precisely returns the aircraft to the assignedaltitude or altitude cleared.

— PNF: Backs up the PF and advises ATC of the event.

NOTE: Normal coordinated TCAS encounters result in nomore than 300 to 700 ft deviation from initial altitudeif in level flight.

The other TCAS commands and responses must be similarly analyzedand coordinated.

The pilot in command is always responsible for the safety of theaircraft.The TCAS system is another tool in the “see and avoid” environment.All flightcrews must have total system knowledge and understand itsoperational capabilities and limitations in order tomake it work for them.

CAUTION

ALTITUDE EXCURSIONS TO CARDINAL ALTITUDES NOTASSIGNED, OR BEYOND THAT DIRECTED BY THE TCASSYSTEM, MAY COMPROMISE THE SAFETY OF THE ENTIRE ATCSYSTEMANDMAYCAUSESEVEREANDDANGEROUSEFFECTSFOR ALL.


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TA and RA Responses


7. TA and RA Responses

The following section describes the aural announcements, theVSI/TRA display, and the expected crew response for each type ofadvisory.

TRAFFIC ADVISORIES

TAs are characterized by the display of an solid amber circle (F) oramber no bearing data tag representing the intruder. These may alsobe accompanied by blue or white proximate traffic solid diamonds(z , z ). Traffic is displayed to aid the crew in their visual search forthe intruding traffic.

Response to a Traffic Advisory

See Figure 7--1.

AURAL -- TRAFFIC – TRAFFIC

VISUAL -- Solid amber (F) circle showing the range and relativebearing on the VSI/TRA. Altitude separation and climb/descentinformation is displayed as applicable.

RESPONSE -- Conduct a visual search for the intruder. If successful,maintain visual acquisition to ensure safe separation.

ID--8000287

Traffic Advisory DisplayFigure 7--1


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TA and RA Responses7-2


RESOLUTION ADVISORIES

RAs are characterized by the display of the intruder as a solid redsquare (J) or red data tag in case of a no bearing intruder. Amber TAs(F) and blue (or white) proximate aircraft (z , z ), if any, are alsodisplayed during the time an RA is active. Vertical maneuversrecommended by TCAS to ensure safe separation are displayed by redand green arcs along the VSI scale.

A preventive RA is issued when the TCAS aircraft’s current verticalspeed is already outside the prohibited region. Safety iscompromised if the aircraft is flown at vertical speeds identifiedbya red arc. PreventiveRA visual indicators range from restricting rateof climb or descent, to prohibiting changes in vertical speed altogether.The aural messages MAINTAIN VERTICAL SPEED, MAINTAIN andMONITOR VERTICAL SPEED accompanies a full range of preventiveRAs.

Preventive or corrective weakening or restrictive advisories may beposted after a corrective advisory has been satisfied and the TCASaircraft is projected to have adequate altitude separation. Thesecorrective RAs are said to soften orweaken theadvisory, indicating thata gradual return to the original flight path or clearance is allowed.Whena corrective advisory is softened, the magnitude of the red arcdecreases, and ADJUST VERTICAL SPEED, ADJUST is announced.The new RA restricts the vertical speed the crew can use in returningto the original flight path. ADJUST VERTICAL SPEED, ADJUST isannouncedonly after the initial downgradingof the corrective RA.Usingthe softening or weakening advisory greatly reduces the ultimatealtitude deviation caused by the original corrective RA.

Corrective advisories are issued when the TCAS aircraft’s verticalspeed is within the prohibited region and a change in vertical speed isrequired to ensure adequate separation. Safety is compromised ifthe aircraft is flown at vertical speeds identified by a red arc.CorrectiveRAvisual indicators present the flightcrewwith a target climbor descent rate in green. Different aural announcements are givendepending on the direction of theRA (climb or descent) and onwhetheror not the altitudes of the two aircraft cross.

Strengthened advisories indicate the pilot must increase the rate ofclimb or descent and are issued after corrective advisories when thechanges in the predicted flight paths are insufficient. Strengthenedmaneuvers must be initiated using an incremental 0.35 g maneuverwithin 2.5 seconds of the issuance of the advisory.


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TA and RA Responses


Reverseadvisories indicate that a previously issued correctiveadvisorymust be reversed to ensure safe separation. These advisories areexpected to occur only on rare occasions, usually when a threat aircraftsuddenly changes it’s current flight path (a maneuvering intruder).Reversals can also occur between two TCAS equipped aircraft whenboth are operating in the TA/RA mode.

RESPONSE TO A PREVENTIVE RA

See Figure 7--2.

AURAL -- MONITOR VERTICAL SPEED – MONITOR VERTICALSPEED

VISUAL -- Current vertical speed is not within the prohibited verticalspeed shown on the VSI.

RESPONSE -- The pilot must keep the vertical speed out of the red arcin the VSI display.

NOTES: 1. During a preventive advisory, if the vertical speed isallowed to enter the red arc, a corrective RA mayresult.

2. In this example, the traffic symbols have been omittedfor clarity. All TA, RA, proximate, and no bearing trafficare displayed during an RA.

ID--8000288

Preventive Resolution AdvisoryFigure 7--2


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CORRECTIVE RESOLUTION ADVISORIES

Response to a Climb RA

See Figure 7--3.

AURAL -- CLIMB – CLIMB

VISUAL -- The VSI is red from the negative limit to +1,500 fpm andgreen from +1,500 to +2,000 fpm.

RESPONSE -- Promptly and smoothly establish a climb at 1,500 to2,000 fpm.

NOTE: In this example, the traffic symbols have been omitted forclarity. All TA, RA, proximate, and no bearing traffic aredisplayed during an RA.

ID--8000289

Corrective Resolution AdvisoryFigure 7--3


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TA and RA Responses


Response to a Descend RA

See Figure 7--4.

AURAL -- DESCEND – DESCEND

VISUAL -- The VSI is red from thepositive limit to –1,500 fpm andgreenfrom –1,500 to –2,000 fpm.

RESPONSE -- Promptly and smoothly establish a descent at 1,500 to2,000 fpm.


ID--8000290

Descend Resolution AdvisoryFigure 7--4


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Response to a Crossing Climb RA

See Figure 7--5.

AURAL -- CLIMB, CROSSING CLIMB – CLIMB, CROSSING CLIMB


RESPONSE -- Promptly and smoothly establish a climb at 1,500 to2,000 fpm.

NOTES: 1. This RA is similar to a climb RA. However, it furtherindicates that the host aircraft flight path will cross thatof the intruder.


ID--8000291

Crossing Climb Resolution AdvisoryFigure 7--5


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TA and RA Responses


Response to a Crossing Descend RA

See Figure 7--6.

AURAL -- DESCEND, CROSSING DESCEND – DESCEND,CROSSING DESCEND


RESPONSE -- Promptly and smoothly establish a descent at 1,500 to2,000 feet per minute.

NOTES: 1. This RA is similar to a descend RA. However, it furtherindicates that the host aircraft flight path will cross thatof the intruder.


ID--8000292

Crossing Descend Resolution AdvisoryFigure 7--6


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Response to a Corrective Reduce Climb RA

See Figure 7--7.

AURAL -- ADJUST VERTICAL SPEED, ADJUST

VISUAL -- The VSI indicates the prohibited vertical speed by a red arc.The goal is to make the aircraft smoothly attain the recommendedvertical speed indicated by the green arc.

RESPONSE -- Promptly and smoothly reduce vertical speed to thatshown on the VSI in green.


ID--8000293

Reduce Climb Resolution AdvisoryFigure 7--7


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TA and RA Responses


Response to a Corrective Reduce Descent RA

See Figure 7--8.


VISUAL -- The VSI indicates the prohibited vertical speed by a red arc.The goal is to make the aircraft smoothly attain the recommendedvertical speed indicated by the green arc.

RESPONSE -- Promptly and smoothly reduce vertical speed to thatshown on the VSI in green.


ID--8000294

Reduce Descent Resolution AdvisoryFigure 7--8


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STRENGTHENING ADVISORIES

Response to an Increase Climb RA

See Figure 7--9.

AURAL -- INCREASE CLIMB – INCREASE CLIMB

VISUAL -- The VSI is red from the negative limit to +2,500 fpm andgreen from +2,500 to +3,000 fpm. This indicates that the vertical speedmust be increased to ensure adequate separation.

RESPONSE -- Promptly and smoothly increase the climb rate to 2,500to 3,000 fpm.


ID--8000295

Increase Climb Resolution AdvisoryFigure 7--9


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TA and RA Responses


Response to an Increase Descent RA

See Figure 7--10.

AURAL -- INCREASE DESCENT – INCREASE DESCENT

VISUAL -- The VSI is red from thepositive limit to –2,500 fpm andgreenfrom –2,500 to –3,000 fpm. This indicates that the vertical speedmustbe increased to ensure adequate separation.

RESPONSE -- Promptly and smoothly increase the descent rate to2,500 to 3,000 fpm.


ID--8000296

Increase Descent Resolution AdvisoryFigure 7--10


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REVERSAL RESOLUTION ADVISORIES

Response to a Climb Now RA

See Figure 7--11.

AURAL -- CLIMB, CLIMB NOW! – CLIMB, CLIMB NOW!


RESPONSE -- Promptly and positively maneuver at an incremental0.35 g to establish a 1,500 to 2,000 fpm climb rate. Expect to changepitch at a rate of 2 to 3.5 per second and initiate your response within2.5 seconds of the issuance of the advisory.

NOTES: 1. This climb now advisory follows a descend advisorywhen circumstances require a reversal of verticaldirection to ensure adequate separation.


FINAL ADVISORYINITIAL ADVISORY

ID--8000297

Climb Now Resolution AdvisoryFigure 7--11


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TA and RA Responses


Response to a Descend Now RA

See Figure 7--12.

AURAL -- DESCEND, DESCEND NOW! – DESCEND, DESCENDNOW!


RESPONSE -- Promptly and positively maneuver at an incremental0.35 g to establish a 1,500 to 2,000 fpm descent rate. Expect to changepitch at a rate of 2 to 3.5 per second and initiate your response within2.5 seconds of the issuance of the advisory.

NOTES: 1. This descend now advisory follows a climb advisorywhen circumstances require a reversal of verticaldirection to ensure adequate separation.



ID--8000298

Descend Now Resolution AdvisoryFigure 7--12


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WEAKENING OR RESTRICTIVE ADVISORIES

These corrective advisories include a variety of vertical speedcommands and guidance intended tominimize or constrain the escapemaneuvers or resolve multiple aircraft conflicts in response to an RA.

Adjust Climb or Descent Rate RA

See Figure 7--13.


VISUAL -- The VSI indicates prohibited vertical speed in red and thetarget vertical speed in green.

RESPONSE -- Promptly and smoothly adjust the vertical speed to thatshown on the VSI in green, but do not deviate into the lower red arc.TCAS indicates the altitude separation between the host aircraft andthe intruder above is not sufficient. Separation with the other aircraft isgiven only if flown as defined by the green arc.



ID--8000299

Adjust Climb or Descent Rate Resolution AdvisoryFigure 7--13


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TA and RA Responses


Corrective Non--Crossing, Maintain Rate RA

See Figure 7--14.

AURAL -- MAINTAIN VERTICAL SPEED, MAINTAIN

VISUAL -- Current vertical speed is not within the red restricted verticalspeed shown on the VSI display.

RESPONSE -- Keep the vertical speed out of the red unsafe areas asindicated on the VSI display. The current vertical climb or descentspeed of 4,400 to 6,000 fpm is acceptable.


DESCEND MAINTAINCLIMB MAINTAIN

ID--8000300

Corrective Non--Crossing Maintain Rate Resolution AdvisoryFigure 7--14


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Corrective Altitude Crossing, Maintain Rate RA

See Figure 7--15.

AURAL -- MAINTAIN VERTICAL SPEED, CROSSING MAINTAIN

VISUAL -- The VSI indicates prohibited vertical speed in red and thetarget vertical speed in green.

RESPONSE -- Promptly and smoothly adjust the vertical speed to thatshown on the VSI in green, but do not initiate a maneuver into the redarc. TCAS indicates the altitude separation between the host aircraftand the intruder below is not sufficient. Separation with the intruderaircraft is adequate if a current vertical speed commanded ismaintained. The intruder receives the opposite command.


DESCEND MAINTAINCLIMB MAINTAIN

HOST DISPLAYINTRUDER DISPLAY ID--8000301

Corrective Altitude Crossing Maintain Rate Resolution AdvisoryFigure 7--15


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TA and RA Responses


CLEAR OF CONFLICT ADVISORY

See Figure 7--16.

AURAL -- CLEAR OF CONFLICT

VISUAL -- The VSI red and green arcs on the VSI are removed. Theintruder symbol no longer appears as a red square (J).

RESPONSE -- Promptly and smoothly return to and/ormaintain the lastapplicable ATC clearance unless otherwise directed. Advise ATC of theevent.

NOTE: This advisory completes an RA unless the intruder’s track islost by the system.

ID--8000302

Clear of Conflict AdvisoryFigure 7--16


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8. TCAS Operating Procedures

COMMUNICATION AND COORDINATION WITH ATC

Notify ATC as soon as practical that you have complied with an RA.

OPERATIONS

Normal Operations

For all normal operations, the TCAS mode--selector switch must beplaced in the TA/RA position.

Mode Annunciators

ThemessageTAONLY (white) confirms the selection of the traffic alertonly mode (see Figure 8--1). This message is also displayed whenRAsare inhibited due to a terrain or ground proximity alert, windshear alert,or when the aircraft is either on the ground or at an altitude less than1,000 ft AGL.

ID--8000303

TA ONLY AnnunciatorFigure 8--1


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TCAS Operating Procedures8-2


TCAS OFF (white) is displayed when the mode--selector switch is inXPNDR or STBY (see Figure 8--2). This message is also displayed ifthere has been a failure of the Mode--S Transponder or if themode--selector switch is in the ALT RPTG OFF position.

ID--8000304

TCAS OFF AnnunciatorFigure 8--2

Non--Normal Operations

The VSI/TRA gives visual mode and failure annunciators in the upperleft and right corners, and in the center of the display.


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Failure Annunciators

If an in--flight failure of the minimum equipment required for TCASoperation occurs, TCAS FAIL is displayed to the right of center on thedisplay (see Figure 8--3). Set the control panel mode--selector switchto XPNDR to deactivate TCAS functions and operate with the Mode--STransponder only.

ID--8000305

TCAS FAIL AnnunciatorFigure 8--3

RA FAIL (resolution advisory failure) is shown in the upper left cornerof the display when TCAS cannot display RAs (see Figure 8--4).

ID--8000306

RA FAIL AnnunciatorFigure 8--4


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TD FAIL (traffic display failure) is shown to the right of center of thedisplay if TCAS cannot display TAs (see Figure 8--5).

ID--8000307

TD FAIL AnnunciatorFigure 8--5

In the case of failure of the VSI/TRA itself, an X may be displayedacross the display, as shown in Figure 8--6. A two--digit code located atthe bottom center of the display is given for maintenance information.In other cases, the display may be blank with neither vertical speed norTA displays visible.

10

ID--8000308

Red X DisplayFigure 8--6


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Failure or loss of valid vertical speed input data prevents display of RAinformation. RA FAIL and VSI FAIL are annunciated in the upper leftand upper right corners of the indicator and the VSI arrow is notdisplayed (see Figure 8--7).

ID--8000309

RA FAIL and VSI FAIL AnnunciatorsFigure 8--7

Equipment Failures

The following procedures are to be used in the case of TCAS orMode--S Transponder equipment failures.

D In the case of a TCAS failure, deactivate TCAS by selecting theXPNDR position on the mode--selector switch.

D If the Mode--S Transponder fails, the amber XPNDR FAIL lamplights on the control panel. If this occurs while in flight, switch to analternate ATC transponder and deactivate the failed Mode--STransponder. Notify ATC of the condition prior to entering controlledairspace. If already in controlled airspace, contact ATC immediately.If still on the ground, do not dispatch without reviewing theminimumequipment list (MEL) for theaircraft and considering the type of flightoperation, the route of the intended flight, and the mandatedequipment required for the flight.


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9. TAWS System Description

TAWS INTRODUCTION

The TAWS (Terrain Awareness and Warning System) function iscontained in a module called the Ground Collision Avoidance Module(GCAM). The GCAM provides fully predictive alerts and warnings toprevent Controlled Flight Into Terrain (CFIT) accidents, as well as allthe reactiveGroundProximityWarning System (GPWS) capabilitiesrequired by TSO C151b.

The purpose of the TAWS is to prevent accidents caused by CFIT andsevere Windshear. TAWS, like TCAS, is a situational awarenesssystem. It is not intended to be used for primary navigation of theaircraft.

The TAWS is used to provide the flightcrew with timely informationabout a potential terrain hazard along the route of flight that could resultin a CFIT event. TAWS also offers improved safety with obstacleawareness and alerting as an option beginning with part numbers9000000--XXX07 and XXX08. TAWS’s predictive functions maygenerate terrain caution alert, warning and avoid terrain alerts, andpremature descent alerts (“Too Low Terrain”). If obstacle alerting isenabled, obstacle caution, obstacle warning, and avoid obstacle alertsmay also be generated.

During normal flight operations, the system remains essentially silent.It uses GPS, radio altitude, barometric altitude and other relevant datain combinationwith its internal database information to provide the pilotwith a full--time terrain display. The look ahead function comparesaircraft position and projected flight profile with the terrain database,and if activated, also the obstacle database.

The TAWS design allows for special situations where aircraft areoperating according to approved procedures at altitudes significantlybelow the surrounding local terrain height (for example, approaches insteep valleys). The TAWS design constructs a predictive alert sensor.This sensor can, as an option, be based on actual aircraft performance.This design minimizes nuisance alerts and enhances crewconfidence that TAWS generates alerts that are real threats.

TheTAWS function has anoptional reactivewindshear detector towarnthe flightcrew if the aircraft is in a dangerous windshear condition.

TAWS provides caution and warning visual annunciations and auralalerts. In addition, it has all the basic GroundProximityWarningSystem(GPWS) alerts. TAWS has unique advisories lines (Terrain AdvisoryLine) and unique warning alerts (Avoid Terrain). The basic GPWSfunction relies on the downward--looking radio altimeter.


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TAWS System Description9-2


ACSS has an optional TAWSperformance systemwhich utilizes actualaircraft performance and configuration data in its predictive alerting.This allows the ACSS TAWS to provide alerts in a more timely manner.

The ACSS TAWS has both Airbus and non--Airbus configurations.

NON--AIRBUS T2CAS PART NUMBERS

The non--Airbus T2CAS part numbers are listed in Table 9--1.

Non--Airbus T2CAS Part Numbers

9000000--10002, 9000000--10003, 9000000--10004,9000000--10005, 9000000--10006, 9000000--10007,

9000000--10008

9000000--20002, 9000000--20003, 9000000--20004,9000000--20005, 9000000--20006, 9000000--20007,

9000000--20008

9000000--55002, 9000000--55003, 9000000--55004,9000000--55005, 9000000--55006, 9000000--55007,

9000000--55008

NOTE: See Appendix F for Airbus Part Numbers.

Non--Airbus T2CAS Part NumbersTable 9--1

TAWS SYSTEM COMPONENTS

The basic TAWS system (see Figure 9--1) described in this manualconsists of the following:

D Forward looking function -- contained in the T2CAS LRU.

D Reactive GPWS function -- contained in the T2CAS LRU.

D Aircraft Personality Module -- remotely mounted

D Terrain display -- cockpit mounted

D TAWS control panel -- cockpit mounted

D GPS receiver -- external or internal to the T2CAS LRU.

NOTE: Position data is required for TAWS operation. Positiondata can come from an approved RNAV system or GPS.GPS data can be provided from an external GPS receiveror from an optional GPS receiver inside the T2CAS LRU.


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Basic TAWS SystemFigure 9--1

Ground Collision Avoidance Module (GCAM)

TheGCAMprovides predictive alerting for avoidanceof terrain hazardsalong the intended route of flight, as well as all reactive alert modesdescribed in DO--161a and required by TSO C151b. (These reactivealert modes are sometimes referred to as GPWS modes.)

TheGCAM receives inputs fromdifferent aircraft systems. It uses theseinputs, along with an internal terrain database, an internal obstacledatabase, and aircraft specific configuration data, to generate visualand aural terrain and obstacle awareness information for the flightcrew.Typical aircraft interfaces to the GCAM are indicated by the dashedboxes in Figure 9--2.


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Typical GCAM InterfacesFigure 9--2

Collision Prediction and Alerting (CPA)

The GCAM predictive functions are provided by an advanced collisionprediction and alerting (CPA) function and optionally, an obstaclecollision prediction and alerting function (OCPA). The CPA and OCPAare also known as the forward looking functions. These functionsencompass terrain, obstacle, and airport databases, as well asmodeling of the aircraft climb capability. The CPA function predictsterrain hazard situations, and generates aural, visual, and graphicaldisplay alerts. Similarly, the OCPA function predicts obstacle hazardsituations, and generates aural, visual, and graphical display alerts.

NOTE: In this Pilot’s Guide, CPA refers to “collision prediction andalerting” in the context of TAWS operation and “closest pointof approach” in the context of TCAS operation.

The CPA function predicts potential terrain conflicts by comparing twoprofiles:

D Terrain Environment Determination -- The terrain environment isdetermined by correlating precise aircraft position information fromGPS and/or FMS sources with internally stored worldwide digitalterrain and airport databases.

D Aircraft Flight Path Prediction -- Aircraft flight path is predictedusing current aircraft flight path parameters to project the aircraftflight path up to two minutes ahead of the current aircraft position.


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The OCPA Function predicts potential obstacle conflicts similarly to itsdetection of terrain conflicts. The OCPA function compares the aboveaircraft flight path prediction with:

D Obstacle Environment Determination – The obstacleenvironment is determined by correlating precise aircraft positioninformation from GPS and/or FMS sources with aninternally--stored, digital obstacle database. This database consistsof human--made objects, greater than 100 feet above ground level,such as radio towers, buildings, and smoke stacks.

NOTE: It is possible that not all obstacles greater than100 feet aboveground level are included in the database.

Figure 9--3 shows the CPA function and the reactive modes as theyinterface with other GCAM functions.

CPA Function and Reactive ModesFigure 9--3


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GPS Receiver

T2CAS may be optionally equipped with an internal GPS module. Thisfeature is intended for aircraft that are not already equipped with anaccurate source of positioning information for the GCAM.

A full--featured navigation--capable GPS is available as an option(installed internally in the LRU). The GPS module is supplied by CMCElectronics Inc. and meets TSO C129a Class B1/C1.

Aircraft Personality Module (APM)

T2CAS uses an ARINC standard APM for storing aircraft--specificconfiguration information. The APM is a programmablememory deviceconnected to the T2CAS. The specific aircraft configuration informationand operator callout selections are uploaded to the T2CAS duringpower--up and upon request.

Some of the information included in the APM is:

D Aircraft climb performance data (if performance option is enabled)

D Aircraft weight information (if performance option is enabled)

D Aircraft--specific input/output characteristics

D Alert prioritization (with respect to other aircraft systems)

D Display specifics and colorization

D Alert repetition rates

D Callout selection and enable

D Aural and visual annunciator settings

NOTE: Airbus T2CAS do not use APM.


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Terrain Display

Terrain hazard information is typically displayed on an existingelectronic flight instrument system (EFIS) display or color weatherradar display. If an aircraft is not equipped with a compatible display,terrain hazard information can be displayed on a 3 ATI or 5 ATI colordisplay supplied as part of the T2CAS installation.

The 3 ATI display is a dedicated terrain hazard display (THD). Thisdisplay is primarily intended for aircraft that are not equipped with acompatible EFIS or color weather radar display and have limited spaceavailable in the forward instrument panel.

The 5 ATI display is a multi--function display (MFD) that can displayterrain, weather radar, and traffic information on a single display unit.

TAWS Control Panel

The TAWS controls can be mounted on a single control panel or theycan be discrete switches individually mounted at a convenient locationin the cockpit. In installations where TAWS information is displayed onanEFIS or electronic display, someTAWS controls may be a part of theelectronic display menu selections.

The TAWS controls are used to control the displayed terrain data andTAWS inhibit features. There may be one or two TAWS control panelsin the cockpit, depending on the TAWS display capability.


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TAWS THEORY AND DESCRIPTION

The TAWS system performs the following functions:

D Processes inputs from aircraft systems

D Correlates current aircraft position to terrain and airport databases

D Projects the terrain hazards along the projected flight path ahead ofthe aircraft

D Generates an image of potential terrain hazards for display in thecockpit

D Determines climb prediction envelope for terrain avoidance usingdata from the APM

D Generates applicable alerts andwarnings, both aurally and visually,to the flightcrew on select displays.

PILOT REACTIONS TO TAWS ALERTS

Pilot reactions to alerts and warnings will differ according to localregulation authorities, weather conditions, type of warning, phase offlight, and aircraft performance. Pilots should be thoroughly familiarwith “State Authority”, company, or other approved operationalprocedures as required by their aircraft and type of operation.

Pilots should be trained to react toTAWSalerts andwarnings accordingto their company’s polices. Training programswill be required for TAWSjust as they are required for basic GPWS, aircraft stall warning,windshear, engine failures and other emergencies.

Pilots should react to all TAWS aural alerts, display pop--ups and visualannunciations as required by company policy. The amber CAUTIONrequires immediate attention if the condition continues. The redWARNING annunciation is a TAWS warning and requires immediateaction by the pilot.

The forward--looking TAWS function should be inhibited prior to takeoffand/or landing procedures at airports and runways which havepreviously been identified as producing false terrain or obstacle alertsuntil corrections have been made.

To avoid giving nuisance alerts, the forward--looking TAWS functionmust be inhibited when landing or taking off at an airport that is notincluded in the airport database. Use the “Airport Search” function onwww.acsscustomerservices.com/CustomerServices for databasequeries. Pilots may consult publication 8006417--XXX, which is a listingfor each released terrain database and the airports that are included inthat database. XXX denotes the revision number of the database.


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If concerns about the reliability or appropriateness ofTAWSalertsarise,pilots may inhibit the forward--looking TAWS function and contactACSS Customer Technical Support for TAWS Event analysis.

TAWS Constraints

D The T2CAS is a situational awareness system that provides earlyalerts to avoid terrain and, optionally, obstacle avoidance. It is nota navigation system that can be used for aggressive flying.

D When equipped with GPS / FMS inputs, all inputs must be accurateand correct to provide meaningful alerts when terrain isencountered.

D Terrain and Airport database information is embedded in the T2CASterrain database software. Information on manmade obstacles ismaintained separately in the Obstacle database.

D Pilots will not see a TAL as the aircraft approaches a runway.

D When the forward--looking TAWS terrain or obstacle awarenessfunction(s) is inhibited or unavailable, it continues to provide basicGPWS functions (Mode 1 to 5 with Altitude callout, bank angle).Windshear also remains operational.

D Mode 1 (Excessive Descent Rate) is always active and Mode 2(Excessive Terrain Closure Rate) is conditionally activated, in orderto provide supplemental protection when the CPA mode isdetermined to be less accurate in the event of position or TAWSdatabase error.

D To avoid unwanted terrain alerts, the TAWS terrain alerts can beinhibited when landing at airports that are not included in the airportdatabase.

D If an alert is previously determined to be erroneous and is repetitiveat a specific location, the alerting function can be inhibited.Nuisance alerts should be brought to the attention of ACSSCustomer Technical Support representatives for correction.

D Proper altimeter setting is required.

D TAWS self tests are inhibited during normal in air flight operationsavailable only when aircraft is on the ground.


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Predictive and Reactive Warnings

The GCAM generates both predictive and reactive warnings.

Predictive Warnings -- The predictive terrain and obstaclewarnings are provided by advanced forward looking functions thatutilize terrain, obstacle, and airport databases, as well as modelingof the aircraft climb capability. The forward looking functions predictterrain and obstacle hazard situations, and generate aural, visual,and graphical display alerts.

The forward looking functions, combined with the terrain hazarddisplay, give the flightcrew predictive CFIT protection throughout allflight phases from takeoff to landing as long as:

D The position of the aircraft can be computed accurately.

D The aircraft performance data is available (when performanceoption is chosen).

D Nocell or cells of extracted terrain in the forwardpath aremissingor invalid.

D All the required input parameters are valid.

D Terrain inhibit is not selected.

Reactive Warnings -- The reactive terrain warnings include Mode1 through Mode 5 warnings (as referenced in DO--161a), altitudecallouts, and bank angle warnings. Reactive windshear warningmode (optional) is also a reactive mode.

Terrain Database

The terrain database is derived from the World Geodesic System--1984 (WGS--84) reference. The world map is divided into an array ofcells forming a continuous grid over the world’s land areas. A heightvalue is assigned to each cell identifying the highest terrain elevationwithin that cell, referenced to mean sea level (MSL). The cell size ormap resolution increases in approach and terminal areas according toaircraft operational requirements within the cell region.

The following are basic resolutions used for specific aircraft operatingareas:

D Enroute areas are encoded with low resolution cells having adimension of 180 X 180 arc seconds (equivalent to 3 NM X 3 NM atthe equator).


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D Terrain within 21 NM of any airport is encoded with cells having adimension of 30 x 30 arc seconds (equivalent to 0.5 NM X 0.5 NMat the equator). This area may be extended to a radius of 30 NM formountainous airports or other specific airports where thesurrounding terrain necessitates a higher resolution.

D Terrain within 6 NM of a mountainous area airport (MAA) may beencoded with cells having a dimension of 15 X 15 arc seconds(equivalent to 0.25NMX0.25NMat theequator). AnMAA isdefinedas an airport that has terrain more than 2000 ft above the airportelevation within a 6 NM radius of the airport.

NOTE: The above values are typical, however there are exceptions:

1. For latitudes greater than 50 the longitudinal size of eachcell is increased to compensate for the convergence of themeridians.

2. When high--resolution data does not exist at a givenlocation, lower resolution data is used.

3. Lower resolution data may be used if it can be shown thatthis does not produce unacceptable levels of nuisancealerts.

Coverage of the TAWS Terrain DatabaseThe internal databases of the T2CAS include terrain, chartedman--made obstacles (if activated), and airports.

The terrain and airport database coverage is provided by geographicalarea. U.S. obstacle database coverage is derived from government--and state--supplied data.

Database UpdateUpdates to the database can be obtained either by download fromACSS website or through the ACSS order administrator. Both requirethe use of a CF (Compact Flash) card that can be inserted into the CFcard slot of the T2CAS computer.

The database can be updated during normal maintenance to theaircraft.

The ACSS TAWS database is in full compliance with FAA TSO C151b.ACSS also fully complies with DO--200A for processes applicable tosuch databases and as such will notify both the database provider andour customers should any database errors be identified.

NOTE: Database Update Procedures are provided in T2CAS SDIM(Systems Description and Installation Manual).

NOTE: To verify specific airports in the database, please visitwww.acsscustomerservices.com.


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The resolution of the terrain database relative to the different operatingareas is shown in Figure 9--4.

Terrain Database ResolutionFigure 9--4

In the enroute airspace theCPA terrain conflict sensors correlate to theterrain database with a 3 NM resolution. When the aircraft enters theairport terminal area airspace, the database resolution increases to0.5 NM. This means the predictive CFIT protection adapts seamlesslyto low altitude tactical maneuvers without generating nuisancewarnings. The forward looking function uses the same terrain conflictdetection rules (with up to twominutes look--ahead) in the terminal areato predict potential CFIT threats.


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Airport Database

The airport database is derived from navigation database data (ARINC424) and may be further adapted to customer specific requirements.This database contains airport specific information, including runwaylocations and features for all airport areas.

Obstacle Database

TheObstacle Database is used by the OCPA function when correlatingcaution, warning, and avoid clearance sensors with potential obstaclehazards. Obstacles in thedatabaseare definedas thosehuman--madeobjects such as towers, buildings, and antennas with a height of at least100 ft. AGL. The obstacle database is assembled from a combinationof FAA and other state--supplied data by approved sources.

Aircraft Altitude

When the aircraft is high above the terrain, the forward looking functionuses GPS and/or barometric corrected altitude in its terrain clearancecalculations. In alternate applications where GPS is not available,barometric altitudemay be used exclusively. See Appendix F for AirbusApplications.

At lower altitudes, the radio altimeter provides higher accuracy(measured height) of aircraft position relative to the terrain. As theaircraft moves closer to the terrain, during enroute situations or duringterminal area maneuvers, the GCAM automatically refines its verticalheight precision by consolidating computed height and measuredheight. (See Figure 9--5.) This method accounts for elevationregistration errors between actual terrain and the terrain database.Below 700 ft, the terrain clearance calculations are made using onlymeasured radio altitude.


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Aircraft Altitude DeterminationFigure 9--5

Perspective View for Terrain Detection EnvelopeBoundaries

D T2CAS has three clearance sensors that are used to provideindications and alerts. The three sensors are:

- Caution Clearance Sensor: generates TAL (Terrain AdvisoryLine) and Caution Alerts, including a Premature DescentAlert (PDA)

- Warning Clearance Sensor: generates Pull--up warningalerts

- Avoid Clearance Sensor: generates Avoid warning alerts.

D Each sensor has two basic parts:

- Short--term propagation of current flight path angle (in theshort term, the aircraft is likely to keep doing what it iscurrently doing)

- Long--term prediction of aircraft potential climb gradient(how the aircraft is likely to climb if a terrain alert occurs)

See Figure 9--6 for the terrain detection envelope boundaries.


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Terrain Detection Envelope BoundariesFigure 9--6

Terrain Caution, Warning, and Avoid Envelopes

The forward looking function continuously correlates theprojected flightpath up to two minutes ahead of the aircraft against an internal terrainelevation database. Alerts are generatedwhenever the forward lookingcalculations show the projected flight path intersects the correlatedterrain elevations underlying that flight path. These calculations includethree dynamically independent conflict detection algorithms, a leadingcaution clearance sensor, a following warning clearance sensor, and atrailing avoid clearance sensor. (See Figure 9--7.)


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Caution, Warning, and Avoid Clearance SensorsFigure 9--7

The clearance sensors can be thought of as virtual “bumpers” thatextend in front of the aircraft. When the virtual bumper encountersterrain (as stored in the terrain database), an alert condition is detected.The type of alert depends on which sensor (avoid, warning or caution)contacted the terrain.


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All other parameters being equal, the point in time that an alert isgenerated may vary, depending on the terrain, aircraft flight path, andaircraft climb capability. For example:

D An alert will occur earlier for a higher mountain than a lower one.

D An alert will occur earlier for a descending aircraft than an aircraftflying level.

D An alert will occur earlier for an aircraft with a reduced orperformance limited climb capability (when performance climboption is enabled).

In thehorizontal plane, theenvelopeor coveragearea for terrainconflictdetection during straight flight is a narrow field of view, beginning witha circle of uncertainty based on lateral accuracy, diverging at a 1.5angle on either side of the flight path as it extends outward in front ofthe aircraft (see Figure 9--8). This narrow view ensures that terrain oneither side of the flight path does not initiate unnecessary alerts andwarnings. Once the aircraft initiates a turn, the forward looking functionuses the aircraft turning rate to extrapolate terrain conflict detectionover the full terrain area underlying the projected turn between thepresent aircraft track and the track that is projected by the turning rate,up to 90.

ID--8003090--001

Horizontal Terrain Conflict EnvelopeFigure 9--8


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TERRAIN CAUTION ENVELOPE

In the vertical plane, the forward looking cautionenvelope extends fromthe aircraft along the flight path to a point 20 seconds in front of theaircraft. From the point 20 seconds in front of the aircraft, the clearancesensor extends up to an additional 112 seconds at an angle equal to thecalculated climb capability of the aircraft. The 20--second envelopeprovides a comfortable time--to--react point for the crew to initiate anormal climb recovery. The envelope follows the maximum climbcapability gradient for the aircraft model; acknowledging the fact thatthe crew and aircraft have the ability to initiate a climb to avoid theterrain. The climb gradient is determined as the best angle of climbusing the existing climb capability of the aircraft, considering weight,baro altitude, air temperature, aircraft configuration, engine out status,and climb data for the aircraft model. If the optional performancefunction has not been activated, climb capability is set to the climbgradient required by TSO C151b.

TERRAIN WARNING ENVELOPE

The forward looking warning envelope is similar in construction to thecaution envelope, except that it follows the flight path angle eightseconds ahead of the aircraft before extending along the constructedflight path to apoint 120 seconds aheadof theaircraft. Theeight secondwindow represents the maximum expected time for the crew to reactand initiate a recovery maneuver.

TERRAIN AVOID ENVELOPE

The forward looking avoid envelope is similar in construction to thecaution and warning envelopes, except that it follows the flight pathangle one second ahead of the aircraft before extending along theconstructed flight path to a point 120 seconds ahead of the aircraft.

When the forward--looking avoid envelope detects a terrain threat, it ispossible that a classic pull--up maneuver will not be sufficient to clearthe terrain and an alternate course of action may be required.


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TERRAIN CAUTION ALERTS AND WARNINGS

If the optional climb performance function is activated, the forwardlooking function uses an aircraft climb rate model to project the actualescape capability for the aircraft as part of its flight path predictioncalculation. This feature is key to forward looking software ability toincrease the time interval for terrain avoidance actions rather thanreactive actions typically associatedwith terrain warning. If the optionalclimb performance is not activated, the aircraft climb rate modeldescribed in TSO C151b is used instead.

The forward looking software provides information through a series ofcaution alerts and warnings to indicate if a classic pull--up maneuver issufficient to prevent a CFIT event. (See Figure 9--9.)

Pull Up WarningFigure 9--9


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If a pull--up maneuver is not sufficient for the aircraft to clear the terraindirectly along the flight path, the forward looking software generates aunique Avoid TerrainWarning (see Figure 9--10) to notify the flightcrewthat, based on the operational status of the aircraft (performancemodel), an alternate course of action (left or right turn) may benecessary to avoid a CFIT situation.

Avoid Terrain WarningFigure 9--10

The forward looking function generates four basic types of terrain alertsand/or warnings.

D Premature Descent Alert -- A Too Low Terrain alert is generatedwhenever the caution clearance sensor detects a potential terrainhazard such that a level off maneuver is sufficient.

D Terrain Caution Alert -- A Terrain Caution alert is generatedwhenever the caution clearance sensor detects a potential terrainhazard such that a level off maneuver is insufficient to avoid theterrain hazard.

D Pull Up Warning -- A Pull Up Warning is generated whenever thewarning clearance sensor detects an imminent CFIT situation dueto the intersection of the warning clearance sensor with a potentialterrain hazard.


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D Avoid Terrain Warning -- An Avoid Terrain Warning is generatedwhenever the avoid clearance sensor determines the current flightpathwill lead theaircraft into high terrain that cannot be cleared (withsufficient margin) with a vertical escape maneuver.

A yellow terrain advisory line is displayed along the points where aterrain caution alert will occur if the aircraft continues along its currenttrajectory. However, potential future obstacle caution alerts (availablewith the optional obstacle awareness function) do not produce terrainadvisory lines. This terrain advisory line is described in detail in Section10, TAWS Operation.

The caution alerts and warnings have aural and visual annunciatorsthat are generated by TAWS. These annunciators are described indetail in Section 11, TAWS and Reactive Windshear Annunciators.


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Convergence Envelope

As the aircraft enters the approach sector (approximately 2.7 NM or5 km from the runway threshold), the system begins to measure theaircraft approach relative to an imaginary convergence envelopeextending from the runway threshold. The convergence envelopedefines the boundaries for a safe arrival at the runway threshold.Forward looking alerts are suppressed as long as the calculationsindicate that the aircraft can converge (i.e., a safe non--CFIT approachis predicted). If the calculation shows the aircraft will not convergeproperly, the forward looking function is enabled and generatesappropriate alerts, should a CFIT potential exist.

The convergence envelope has the approximate shape of a funnel withthe smallest part being a landing box that approximately overlays therunway threshold. (see Figure 9--11.) The bottom and top of theconvergence envelope accommodate normal and steep approaches,while the sides are defined to accommodate straight--on and curvedapproaches. The aircraft can approach and enter the envelope fromany direction and convergence is calculated accordingly.

TAWS Convergence EnvelopeFigure 9--11


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GPWS Modes of Operation

The forward looking function (CPA) also operates in the reactive alertmodes described inDO--161aand requiredbyTSOC151a. (SeeFigure9--12.)

GCAM CFIT Protection and Flight PhasesFigure 9--12

Unlike the predictive alert modes which are active in all flight phases,the reactive alert modes are only active during specific flight phases.These reactive alert modes are sometimes referred to as GPWSmodes.

In order to minimize warning confusion and nuisance distractions,Mode 2 is normally suppressed by the forward looking function and isautomatically reactivated if a position error, altitude error, or databaseerror is detected. All other reactive modes automatically engage duringthe appropriate phases of landing and takeoff.

MODE 1 -- EXCESSIVE DESCENT RATE

Thismodemonitors the radio altitude and vertical speed and generatesa reactive medium--term caution and a reactive short--term warningwhen the current flight path is descending at an excessive rate.


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The following alerts can be generated by Mode 1:

D Sink Rate Caution -- A Sink Rate Caution is generated when radioaltitude and vertical speed are within the sink rate envelope, asdescribed in Figure 9--13, for at least one second. When a Mode 1Sink Rate Caution is generated, the caution annunciator lights andSINK RATE is announced over the speaker system, or over theheadsets depending on the installation. When the “steep approach”option is selected by the crew, the sink rate envelope is modified asindicated in Figure 9--13. The Sink Rate Caution is reset as soon asthe radio altitude and vertical speed are detected outside the sinkrate envelope.

D Pull Up Warning -- A Pull Up Warning is generated when radioaltitude and vertical speed are within the pull up envelope, asdescribed in Figure 9--13, for at least 0.5 second. When a Mode 1Pull Up Warning is generated, the warning annunciator lights andPULL UP, or WHOOP WHOOP PULL UP is announced over thespeaker system, or over the headsets depending on the installation.The Pull Up Warning is reset as soon as radio altitude and verticalspeed are detected outside the pull up envelope.

NOTE: When activated, the ”Steep Approach” function dynamicallyreduces the size of the Mode 1 envelope to reduce nuisanceMode 1 alerts in more aggressive steep approaches (seeFigure 9--13). The Steep Approach function compares theapproach angle of the target runway (as defined in the airportdatabase) with a customer--selectable Steep ApproachThresholdAngle. If the database indicates anapproachanglegreater than the pre--determined threshold, the SteepApproach envelope is activated. The ”Steep Approach”feature is activated either manually by a ”Steep Approach”switch in the cockpit (if installed) or by theoptional AutoSteepApproach function. Refer to your AFM (or AFM supplement)to determine if either of these options is applicable to yourinstallation.


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Sink Rate Caution and Pull Up Warning Envelopesfor Reactive Mode 1

Figure 9--13


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MODE 2 -- EXCESSIVE TERRAIN CLOSURE RATE

Thismodemonitors the radio altitude, computedairspeed, landinggearconfiguration, and landing flaps configuration and generates a reactivemedium--term caution and a reactive short--term warning when thecurrent flight path and the terrain are closing at an excessive rate.

NOTE: When the forward looking function is operative and all inputdata consistency checks are satisfied, Mode 2 alerts aresuppressed. Mode 2 is automatically reactivated if any of theconsistency checks fail.

The following alerts can be generated by Mode 2:

Terrain Caution -- A Terrain Caution is generated when radioaltitude and terrain closure rate are one of the following:

D Within the red envelope in Figure 9--14 for one second if the flapsare not in a landing configuration and the flaps override is not set(Mode 2A)

D Within the amber envelope in Figure 9--14 for one second if theflaps are in a landing configuration or if the flaps override is set(Mode 2B).

When a Mode 2 Terrain Caution is generated, the cautionannunciator lights and TERRAIN TERRAIN is announced over thespeaker system, or over the headsets depending on the installation.TheTerrain Caution is reset as soon as the radio altitude and terrainclosure rate are detected outside the Mode 2A or Mode 2Benvelope.

Pull UpWarning -- The Mode 2 Terrain Caution transitions to aPullUpWarning if the landing gear is not in the landing configuration andif radio altitude and terrain closure rate are one of the following:

D Within the red envelope in Figure 9--14 for three seconds if theflaps are not in a landing configuration and the flaps override isnot set (Mode 2A)

D Within theamber envelope inFigure 9--14 for threeseconds if theflaps are in a landing configuration or if the flaps override is set.


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When a Mode 2 Pull Up Warning is generated, the warningannunciator lights and appropriate aural, based on ACD selection,is announced over the speaker system,or over the headsetsdepending on the installation. The Pull UpWarning is reset as soonas the radio altitude and terrain closure rate are detected outside theMode 2A or Mode 2B envelope.

Terrain Caution and Pull Up Warning Envelopes for Mode 2Figure 9--14


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MODE 3 -- LOSS OF ALTITUDE AFTER TAKEOFF OR GOAROUND

This mode monitors the radio altitude and aircraft altitude andgenerates a caution alert when there is loss of altitude after takeoff oramissedapproach. TheDon’t SinkCaution is generatedwhen the radioaltitude and the altitude loss is within the don’t sink envelope describedinFigure 9--15. Thealtitude loss is thedifferencebetween themaximumaltitude reached during takeoff and the current altitude.

When a Mode 3 Don’t Sink Caution is generated, the cautionannunciator lights and DON’T SINK is announced over the speakersystem, or over the headsets depending on the installation.

TheDon’t SinkCaution is reset as soon as the radio altitude andaltitudeloss are detected outside the Mode 3 envelope or if the vertical speedis positive for more than one secondwhile the radio altitude andaltitudeloss are still within the envelope. After being reset while the radioaltitude and altitude loss are still within the envelope, the Don’t SinkCaution is generated again if the vertical speed becomes negative formore than one second.


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Don’t Sink Caution Envelope for Mode 3Figure 9--15


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MODE 4 -- UNSAFE TERRAIN CLEARANCE NOT IN LANDINGMODE

This mode monitors the radio altitude, landing gear configuration,landing flaps configuration, and airspeed and generates a caution alertif there is insufficient terrain clearance when the aircraft is not in theproper landing configuration. Specific aural annunciators (TOO LOWGEAR or TOO LOW FLAPS) are generated to inform the pilot ofspecific unwanted landing configurations. Mode 4 can generate thefollowing alerts:

Too Low TerrainCaution -- A Too Low TerrainCaution is generatedwhen radio altitude and airspeed are within the Too Low Terrainenvelope described in Figure 9--16.

When a Mode 4 Too Low Terrain Caution is generated, the cautionannunciator lights and TOO LOW TERRAIN is announced over thespeaker system. This caution is annunciated as long as thecondition exists.

Too Low Gear Caution -- A Too Low Gear Caution is generatedwhen radio altitude and airspeed are within the Too Low Gearenvelope described in Figure 9--16 and the landing gear is not in acorrect landing configuration.

When a Mode 4 Too Low Gear Caution is generated, the cautionannunciator lights and TOO LOW GEAR is announced over thespeaker system. This caution is annunciated as long as thecondition exists.

The TOO LOW GEAR message can be inhibited by engaging thelanding gear override switch (if installed).

Too Low Flaps Caution -- A Too Low Flaps Caution is generatedwhen radio altitude and airspeed are within the Too Low Flapsenvelope described in Figure 9--16 and the flaps are not in a correctlanding configuration.

When a Mode 4 Too Low Flaps Caution is generated, the cautionannunciator lights and TOO LOW FLAPS is announced over thespeaker system. This caution is annunciated as long as thecondition exists.

The TOO LOW FLAPS message can be inhibited by engaging theflap override switch (if installed).


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Too Low Terrain/Gear/Flaps Envelope for Mode 4Figure 9--16


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MODE 5 -- EXCESSIVE DESCENT BELOW GLIDESLOPE

This mode monitors the radio altitude, glideslope deviation, localizerdeviation, landing gear configuration, and glideslope inhibit/cancel. Itgenerates a caution alert if there is excessive descent below theinstrument glidepath when making a front course approach with thegear down.

In some configurations, Mode 5 monitors ILS back course selection,selected runway heading, and track angle. Some configurations alsoautomatically inhibit Mode 5 while in a back course approach. TheGlideslope Caution is generated when the radio altitude and theglideslope deviation are within one of the two envelopes described inFigure 9--17.

When aGlideslopeCaution is generated, the caution annunciator lightsand GLIDESLOPE is announced over the speaker system. Thismessage is normal volumewhen the radio altitudeand glideslope (G/S)deviation are within the Mode 5B envelope and (based on operatoroption settings) are reduced in volume by 6 dB when within the Mode5A envelope.

The Glideslope Caution is repeated more frequently as the belowglideslope deviation increases and/or the radio altitude decreases.

The Glideslope Caution is generated as long as the radio altitude andthe glideslope are within one of the two Mode 5 envelopes, except if itis canceled by the crew with the G/S CANCEL switch. The G/SCANCEL annunciator lights to indicate the alert has been canceled. Itremains lit while the radio altitude is between 30 ft and 1,000 ft.

Mode 5 can bemanually inhibited by the flightcrew before the approachby selecting the G/S INHIBIT switch (if installed). It is also inhibited ifany of the following conditions exist:

D The angle between the selected runway heading and track angle isgreater than 90.

D The localizer deviation is outside of +/-- three dots.

D The landing gear is up.

D Instrument landing system (ILS) back course is selected.


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Excessive Descent Below Glideslope Envelope for Mode 5Figure 9--17


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MODE 6 -- EXCESSIVE BANK ANGLE AND ALTITUDECALLOUTS

This mode monitors the radio altitude and bank angle, and generatesan aural annunciator (BANK ANGLE) when the aircraft bank angleexceeds a bank angle limit defined with respect to radio altitude asdescribed in Table 9--2.

Radio Altitude Bank Angle Limit

Between 30 ft and 150 ft Linear from 10 (30 ft) to 40 (150 ft)

Between 150 ft to 2450 ft Linear from 40 (150 ft) to 55 (2450 ft)

Above 2450 ft 55

Bank Angle Limits for Excessive Bank Angle CautionTable 9--2

If the bank angle is within the excessive bank angle envelope (seeFigure 9--18), two BANK ANGLE messages are generated 0.75seconds apart, then the Excessive Bank Angle envelope is shifted toincrease the bank angle thresholds by 20%. If the bank angle is insidethe new envelope, two more BANK ANGLE messages are generatedand the Excessive Bank Angle envelope is shifted by 40% from theoriginal. If the bank angle is inside the newer envelope, the BANKANGLE message is generated continuously until the bank angle isdecreased to outside of the original excessive bank angle envelope.


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Excessive Bank Angle Envelope for Mode 6Figure 9--18


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MODE 6 -- ALTITUDE CALLOUTS

The system monitors radio altitude, selected decision height (DH),below DH, landing gear configuration, and callout enable, andgenerates altitude callouts for descent below a set of customer definedaltitudes. Each selected altitude callout is delivered once and then thecallout process is reactivated only when the radio altitude is greaterthan 1,080 ft.

An altitude callout is inhibited if it is within three feet of the selecteddecision height and the operator has selected at least one decisionheight callout.

Decision Height Callout requests may be activated via discrete inputfrom an external system. With this interface, the T2CAS unit cannotanticipate the selected Decision Height value. As a result, if a lowerpriority altitude callout is annunciating and a DH or MDA callout isrequested, the TAWS system will await the completion of the currentannunciation before issuing a DH/MDA callout. This may slightly delaythe DH/MDA annunciation.

Radio Altitude Radio Altitude Callout

2,500 ft TWO THOUSAND FIVE HUNDREDor TWENTY FIVE HUNDRED orRADIO ALTIMETER VALID

1,000 ft ONE THOUSAND

500 ft FIVE HUNDRED

500 ft Two second 960 Hz tone

400 ft FOUR HUNDRED

300 ft THREE HUNDRED

200 ft TWO HUNDRED

100 ft ONE HUNDRED

100 ft Two second 700 Hz tone

80 ft EIGHTY

60 ft SIXTY

50 ft FIFTY

40 ft FORTY

35 ft THIRTY FIVE

35 ft One second 1400 Hz tone

Altitude CalloutsTable 9--3 (cont)


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Radio Altitude Radio Altitude Callout

20 ft TWENTY

20 ft 0.5 second 2800 Hz tone

10 ft TEN

Altitude CalloutsTable 9--3

Selectable altitude callouts are also listed in Section 11, TAWS andReactive Windshear Annunciators.


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DECISION HEIGHT AND MINIMUM DESCENT ALTITUDECALLOUTS

When the landing gear is down, the following decision height andminimum descent altitude (MDA) callouts are generated (if selected byoperator). Each callout is delivered once and then the callout processis reactivated only when the radio altitude is greater than 1,080 ft.

If the selected DH is invalid, UNKNOWN DECISION HEIGHT isannounced when the radio altitude is 900 ft (if at least one decisionheight callout has been selected by the operator).

If the selected DH is less than 10 ft or more than 800 ft, all decisionheight callouts are inhibited.

Radio Altitude (DH) orBaro Altitude (MDA) Callout

Selected DH + 100 ft APPROACHING DECISION HEIGHT

Selected DH DECISION HEIGHT

Selected MDA +80 ft APPROACHING MINIMUM

Selected MDA MINIMUM or MINIMUM, MINIMUM

DH and MDA CalloutsTable 9--4


The TAWS function incorporates a reactive windshear feature that isavailable as an optional part of the terrain awareness system, based onaircraft requirement. The reactive windshear system monitors aircraftperformance on both takeoff and approach to identify the presence ofsevere low--level, downburst/microburst--type windshear. The reactivewindshear system is described in detail in Section 12, ReactiveWindshear System.


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COLD WEATHER OPERATIONS

The Barometric Altimeter is inaccurate at non--standard temperatures.Colder than standard air temperature can cause the barometricaltimeter to indicate a higher altitude than actual. This results in theaircraft being flown lower than intended and can contribute to a CFITaccident.

The corrected barometric altitude input is compensated to account forthe colder--than--standard air temperature using the Cold TemperatureCompensation algorithm if the Cold Temperature Compensation logicis enabled during installation through the customer’s aircraft specificdatabase.


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10. TAWS System Operation

In a typical installation, the TAWS function in T2CAS powers up, runsan internal self--test, and is ready for operation without any input fromthe flightcrew. There are several functions of TAWS that the flightcrewcancontrol once the systemhas powered--upand is operatingnormally.

TAWS CONTROLS

The TAWS controls can be mounted on a single control panel or theycan be discrete switches individually mounted at a convenient locationin the cockpit. There may be one or two TAWS control panels in thecockpit, depending on the TAWSdisplay capability. The TAWS controlsmay be part of an EFIS menu, depending on the aircraft installation.

NOTE: The following controls and annunciators may or may not beavailable in all aircraft installations. Consult the ApprovedFlight Manual for a detailed description of the controls andannunciators for a specific aircraft installation.

The TAWS controls can include the following:

D Terrain Display -- The terrain display control is typically a togglebetween weather radar information and terrain hazard information.

D Terrain Inhibit -- The terrain inhibit control inhibits the terraindisplayand forward looking functions.

D Obstacle Inhibit -- The obstacle inhibit control inhibits the obstacleforward looking functions and theassociated display of obstacles onthe terrain hazard display. On some configurations, this control istied to the Terrain Inhibit control.

D Obstacle Display Inhibit -- The obstacle display inhibit controlinhibits the display of non--alerting obstacles on the terrain hazarddisplay. Obstacle forward looking functions and alerting remainactive.

D GPWS Inhibit -- Inhibits the reactive GPWS Modes 1--5.

D Self Test -- The self test control initiates a self--test of TAWS thatincludes generating a test pattern of the terrain display features. TheTAWS self--test is described in detail later in this section.

D Glideslope Inhibit -- The glideslope inhibit control inhibits theexcessive glideslope deviation warning.


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TAWS System Operation10-2


D Glideslope Cancel -- The glideslope cancel control cancels theexcessive glideslope deviation warning for the current approach.

D Momentary Audio Alert Suppress -- This control suppresses thecurrent audio alert. Another active lower priority alert mayannunciate once the higher alert is suppressed.

D AltitudeCallout Disable -- This control disables the altitude calloutfor the current approach.

D Mode 6 Volume -- This control decreases the audio level of theMode 6 aural alerts (altitude callouts, minimums callouts(approaching minimums, approaching decision height) and bankangle callouts.

D FlapOverrideSwitch -- The flap override switch overrides the flapssetting that TAWS senses. This suppresses the TOO LOW FLAPScaution generated by reactive Mode 4, selects the Mode 2Benvelope, and satisfies the flap requirement for the convergenceenvelope.

D Gear Override Switch -- The gear override switch overrides thegear position that TAWS senses. This suppresses the TOO LOWGEAR caution generated by reactive Mode 4, inhibits the Mode 2warning, and satisfies the gear requirement for the convergenceenvelope.

D Steep Approach Switch -- The steep approach switch selects thealternate Mode 1 curve.

D Back Course Select Switch -- The back course select switchindicates to the TAWS that the aircraft is performing a localizer backcourse approach.

D DH/MDA -- Selects DH or MDA for callout.

D Lamp Test -- The lamp test switch typically tests all of the cockpitcaution and warning annunciator lamps.

The TAWS annunciators indicate TAWS status. These annunciatorstypically include the following:

D TERR/WX RDR Display Annunciator -- Indicates whether theassociateddisplay is displaying terrain orweather radar information.

D TERR INHIB -- Indicates if the terrain display and forward lookingfunctions have been inhibited.


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D OBST INHIBIT Annunciator – Indicates if obstacle forward lookingfunction and display have been inhibited.

D TERR FAIL or TERR N/A Annunciator -- Indicates if terraininformation has failed or is not available.

D GS INHIB Annunciator -- Indicates if the excessive glideslopedeviation warning is inhibited.

D GPWS FAIL or GPWS INHIB -- Indicates if the GWPS functionshave failed or are inhibited.

D W/S FAIL -- Indicates if the windshear functions have failed.

Figure 10--1 shows an example of a TAWS control panel.

Typical TAWS Control PanelFigure 10--1


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TAWS DISPLAYS

The forward looking function generates terrain patterns that aredisplayed on a weather radar display, an EFIS display, or anothercompatible display within the flightcrew’s forward field of view. Theterrain information is displayed in a “heading up” or “track up”orientation depending on aircraft configuration. The range is selectablein 5 NM increments up to 320 NM (depending on the range selector forthe display). Terrain information is available during all phases of flight,although in most installations it shares a display with the weather radarand the TERR/WXR switch is used to toggle the display betweenweather information and terrain information. If a terrain or obstacle alertis generated and the display is selected toWXR, the terrain or obstacleinformation automatically “pops--up” on the display (as long as nohigher priority windshear alert is active).

Terrain Information Display

The terrain display gives the flightcrew overall situational awarenessabout the relative height of the terrain near the aircraft. The terrain isdivided into “slices” based on the elevation of the terrain with respectto an aircraft reference altitude. Slices above the reference altitude aretypically displayed as shades of red. Slices near the reference altitudeare typically displayed as varying shades of yellow. Slices safely belowthe reference altitude are typically displayed as varying shades ofgreen or solid black.

The aircraft reference altitude is a surface starting at the aircraft,propagating forward along the aircraft flight path for 30 seconds. Thereference altitude surface then extends horizontally at the altitude theaircraft is expected to have at that time (30 seconds in the future). Asa customer definable option, a user can choose to propagate forwardin descent only and to consider present altitudewhenpositive flight pathangles are present.

The forward looking function also determines the minimum terrainclearance distance (MTCD). The MTCD is the minimum safe distancebetween the aircraft and the terrain when considering a CFIT situation.This clearance is usually about 600 ft when en route and isprogressively reduced to 30 ft in the short final approach phase of flight.The MTCD is used by the Caution and Warning sensors for alertcalculations. The Avoid Sensor uses 30% of the MTCD for alertcalculations.


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Figure 10--2 shows an example of a typical terrain display patterns forvarious terrain elevations with respect to the aircraft reference altitude.

Example of Terrain Display Patterns for Various TerrainElevationsFigure 10--2

NOTE: Terrain cells that don’t have a high quality indicator areconsidered invalid and are displayed in magenta. If theforward looking function has to extract an invalid terrain cell,the forward looking function is deactivated and the TERRINOP annunciator is lit.

NOTE: For Airbus applications, see Appendix F.

The optional obstacle awareness function, if enabled, will displayobstacles with a coloration scheme similar to that of terrain. Obstacleslice colorization is based on the aircraft reference altitude and followsthe same principles as the coloring of terrain slices. However, sinceobstacles are inherently smaller than terrain features, they aredisplayed with higher dot densities (75% density) to enhance theirvisibility on the terrain hazard display. (See Figure 10--3)


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Obstacle Display Patterns for Various Obstacle ElevationsFigure 10--3


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Table 10--1 describes the terrain display patterns shown in Figures10--2 through 10--7.

Terrain Elevation(typical values)

Terrain Color Dot Density

1,000 ft or more abovethe aircraft referencealtitude

Red Medium

0 ft to 1,000 ft abovethe aircraft referencealtitude

Red Low

Maximum of (500 ft,MTCD) below theaircraft referencealtitude to the aircraftreference altitude

Yellow Low

Maximum of (500 ft,MTCD) to 1,000 ftbelow the aircraftreference altitude

Green Medium

1,000 ft to 2,000 ftbelow the aircraftreference altitude

Green Low

2,000 ft or greaterbelow the aircraftreference altitude

Black N/A

Invalid terrain cell Magenta Solid

Terrain Caution Yellow Solid

Terrain Warning Red Solid

Avoid Terrain Red/Black Black with redcross--hatch

Terrain Display Patterns for Various Terrain ElevationsTable 10--1 (cont)


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Terrain Elevation(typical values)

Dot DensityTerrain Color

NOTE: The exact altitudes at which certain colors appear can beconfigured by ACSS. Refer to the Refer to the AFM, AFMsupplement, or Appendix G of this document for thesettings on your aircraft.

NOTE: If the aircraft is within 15 NM of the nearest airport, terrainwith elevation less than the nearest runway elevation+ 400 ft is displayed as Black.

Terrain Display Patterns for Various Terrain ElevationsTable 10--1

Table 10--2 describes the terrain display patterns when the aircraft is inthe vicinity of the airport.

Terrain Elevation Terrain Color Dot Density

1,000 ft or more above theaircraft reference altitude

Red Medium

400 ft to 1,000 ft above theaircraft reference altitude

Red Low

0 ft to 400 ft above theaircraft reference altitude

Black N/A

Terrain Display Patterns for Various Terrain Elevations whenthe Aircraft is in the Vicinity of the Airport

Table 10--2


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Obstacle Elevation(typical values) Obstacle Color Dot Density

1000 ft or more above theaircraft reference altitude

Red High

0 ft to 1000 ft above theaircraft reference altitude

Red High

Maximum of (500 ft, MTCD)below the aircraft referencealtitude to the aircraftreference altitude

Yellow High

Maximum of (500 ft, MTCD)to 1000 ft below the aircraftreference altitude

Green High

1000 ft to 2000 ft below theaircraft reference altitude

Green High

2000 ft or greater below theaircraft reference altitude

Black N/A

Obstacle Caution Yellow Solid

Obstacle Warning Red Solid

Avoid Obstacle Red/Black Black with redcross--hatch

NOTE: The exact altitudes at which certain colors appear can beconfigured by ACSS. Refer to the AFM or AFMsupplementfor the settings on your aircraft.

Obstacle Display Patterns for Various Obstacle ElevationsTable 10--3


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Terrain Advisory Line DisplayA unique feature of the T2CAS terrain display is the terrain advisory line(TAL). The terrain advisory line is drawnalong thepointswhere a terraincaution alert will occur if the aircraft continues along its currenttrajectory. When there are no terrain alerts or warnings active, theforward looking function determines if and where a terrain advisory lineneeds to be drawn. Beginning at the current aircraft position, theforward looking function looks 120 seconds ahead and within1.5 degrees of the current aircraft track. If any terrain cautions wouldbe triggered in this area, the terrain advisory line is drawn on the terraindisplay. Figure 10--4 shows the terrain display with a terrain advisoryline.NOTE: The exact configuration of the TAL is application specific.

Consult your AFM (or AFM supplements) for details.

Terrain Advisory LineFigure 10--4


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NOTE: The terrain advisory line is drawn at the point where theaircraft is expected to be at the time a caution alert will begenerated.


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Terrain Caution and Warning DisplaysWhen a terrain caution or warning occurs, the terrain advisory line isremoved from the display and the terrain display is changed to identifythe terrain that caused the alert. Terrain that prompts a Terrain Cautionalert is displayed in solid yellow. A yellow “TERR” message isgenerated, shown at the top left of this example (see Figure 10--5). Aslong as the Terrain Caution alert exists, the terrain causing the alert isdisplayed in solid yellow. The solid yellow caution area may changedepending on any adjustments that the flightcrew makes to the flightpath.

Terrain Caution AlertFigure 10--5


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Terrain that prompts a Pull--Up Warning is displayed in solid red. A red“TERR” message is generated, shown at the top left of this example(see Figure 10--6). As long as the Pull--Up Warning exists, the terraincausing thewarning is displayed in solid red. The solid redwarningareamay change depending on any adjustments the flightcrewmakes to theflight path. The Pull--Up Warning is generated as long as the currentaircraft trajectory will not safely clear the terrain. (i.e., the warningsensor is intersecting with the terrain).

Pull Up WarningFigure 10--6


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Terrain that prompts an Avoid Terrain Warning is displayed in red andblack cross--hatch (Figure 10--7). As long as the Avoid TerrainWarningexists, the terrain causing the alert is displayed in black with redcross--hatch. This warning area may change depending on anyadjustments the flightcrew makes to the flight path.

Avoid Terrain Warning DisplayFigure 10--7


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In Figure 10--7, TAWS has detected a TerrainWarning in which the PullUp maneuver will not allow for a safe clearance with terrain, and thecrew has to immediately initiate an appropriate vertical and/or turningescape maneuver in order to avoid a CFIT accident. The potentiallyhazardous terrain are in front of the aircraft is highlighted with a red andblack cross hatch pattern. A red “TERR” message is generated, shownat the top left of this example (see Figure 10--7).

NOTE: The yellow and red “TERR” annunciations vary by displaytype and configuration settings and may or may not begenerated. Consult you AFM (or AFM Supplement) fordetails.


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Obstacle Caution and Warning Displays

The Obstacle Collision Prediction and Alerting (OCPA) function utilizesthe same sensor system as the standard terrain CPA function.However, OCPA correlates the sensors with objects within the obstacledatabase.

Both obstacles causing alerts andnon--alerting obstacles are shownonthe terrain hazard display as fixed size squares. The displayed size isnot dependant on the physical size of the obstacle itself.

When an obstacle caution or warning occurs, any terrain advisory linesare removed from the display and the terrain hazard display is changedto identify the obstacle(s) that caused the alert. Obstacles that promptanObstacleCautionalert are displayed in solid yellow.A yellow“OBST”message, shown at the top left in this example (see Figure 10--8) maybe generated depending upon customer settings. As long as theObstacle Caution alert exists, the obstacles causing the alert aredisplayed in solid yellow. The solid yellow caution areas may changedepending on any adjustments that the flightcrew makes to the flightpath.

Obstacle Caution DisplayFigure 10--8


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Obstacles that prompt a Pull--Up Warning are displayed in solid red. Ared “OBST” message, shown at the top left in this example (see Figure10--9) may be generated depending upon customer settings. As longas the Pull--Up Warning exists, the obstacle(s) causing the warning isdisplayed in solid red. The solid red warning area may changedepending on any adjustments the flightcrew makes to the flight path.The Pull--Up Warning is generated as long as the current aircrafttrajectory will not safely clear the obstacle.

Pull Up Warning DisplayFigure 10--9


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Obstacles that prompt an Avoid ObstacleWarning are displayed in redand black cross--hatch (see Figure 10--10). As long as the AvoidObstacle Warning exists, the obstacle(s) causing the alert is displayedin black with red cross--hatch. This warning area may changedepending on any adjustments the flightcrew makes to the flight path.

Avoid Obstacle Warning DisplayFigure 10--10

Terrain Hazard Display

The Terrain Hazard Display (THD) function enhances situationalawareness by providing a display of terrain-- and (if enabled)obstacle--related hazardous situations in front of the aircraft on existingARINC 708 compatible weather radar or EFIS flight deck displays. Thedisplay may be either the EFIS Navigation Display (for EFIS--equippedaircraft) or the weather radar display. A crew--activated switch is usedto select/deselect the terrain image on the display.

If a terrain or obstacle alert is generated while the display is set toweather radar, the terrain image will “pop--up” automatically to displaythe conflicting terrain or obstacle. For displays that support theauto--range feature, the display image will also auto--range (typically to10 NM) when a terrain or obstacle alert is generated.


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The THD function generates an image that provides the followinginformation to the flight crew:

D A Terrain Display Background consisting of shaded areasrepresenting terrain (and obstacles if enabled) at differentaltitudes relative to the aircraft altitude

D ATerrainAdvisory Line depicting the point or pointswhere aCPAcautionwill occur if the aircraft continues on its current trajectory.

D Terrain Alert areas corresponding to the terrain that is causing aCPA caution or warning.

D Obstacle Alert areas (if enabled) corresponding to the obstaclethat is causing an OCPA caution or warning.

Example of a Terrain Hazard Display ShowingAvoid Terrain Warning

Figure 10--11


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Terrain Eleview Display

The Eleview function provides additional terrain display enhancedsituational awareness, independent of aircraft altitude. The TerrainEleview Display (TED) provides information regarding terrain wellbelow the aircraft reference altitude.

This function allows the pilot to identify high and low areas of terrain. Itis very useful during emergencies and improves situational awareness.It also provides a numeric indication of the highest and lowest terrainof interest on the display.

If the Eleview feature is enabled, terrain elevation information isdisplayed to the flight crewas apair of threedigitMSLelevations. Thesenumbers represent the MSL terrain elevation in hundreds of feet (e.g.250 is 25,000 feet). The top number represents the MSL altitude of thehighest displayed terrain and the bottom number represents the MSLaltitude of the lowest displayed terrain. When above the highest terrainelevation by a user--defined altitude, the Eleview function will showthree shades of green to represent terrain. On supporting displays,water can be depicted in cyan. If the display does not support cyan,water will remain black.

Terrain Hazard Display (THD) slices are based on terrain’s distancebelow aircraft reference altitude. Terrain Eleview Display (TED) slicesare sized as a proportion of terrain amplitude (the spread). The spreadconstantly changes as the terrain on the display changes. Note that thepercentages are configurable.

Example of an Eleview SpreadFigure 10--12

NOTE: Whenover flying areas of flat or nearly flat terrain, dividing theterrain into three Eleview slices may not result in a consistentand meaningful display and a reduced number of Eleviewslices will be used.


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Terrain Eleview DisplayFigure 10--13

Display of Terrain Elevations is per the following:

D In hundreds of feet using three digits

D WhenRounded to thenext highest hundred (e.g. 240 ft becomes”003”and --381 ft becomes ”--003”)

D When the rounded max equals the rounded min, only maximumis displayed

D If MAXIMUM is Within 100 feet of MINIMUM, the MINIMUM willbe removed

D Color of digits matches color of slice for corresponding terrain

D Provided in both TED and THD display modes.


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OPERATING MODE REQUIREMENTS

The TAWS terrain, obstacle, and windshear functions (if activated) ofT2CAS operate automatically when all the required inputs are valid. Ifthere are redundant sources, only one source has to be valid. If afunction is not available, it is annunciated to the flightcrew (seeAbnormal Procedures, described later in this section). The following isa list of the data that is required to be valid for the TAWS andwindshearfunctions to be activated.

Collision Prediction and Alerting

D Terrain and airport databasesD Aircraft climb models (if optional performance function is

installed)D Current aircraft weight (if optional performance function is

installed)D Static air temperatureD PositionD AltitudeD Vertical speedD Ground speedD Track angleD Roll angleD Navigation accuracyD Flap position data (otherwise down assumed)D Landing gear position data (otherwise down assumed)D Steep approach statusD Engine out status (if optional performance function is installed)

Terrain Hazard Display

D RangeD PositionD AltitudeD CPA data availableD Configuration dataD Terrain databaseD HeadingD Ground speedD Track angle

NOTE: Obstacle Collision Prediction and Alerting (OCPA) requiresall inputs required for CPA plus a valid obstacle database.


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Reactive Mode 1 -- Excessive Descent Rate

D Vertical speedD Radio altitudeD Steep approach status

Reactive Mode 2 -- Excessive Terrain Closure Rate

D Computed airspeedD Radio altitudeD Flaps position dataD Landing gear position data

Reactive Mode 3 -- Loss of Altitude After Takeoff

D Vertical speedD Radio altitudeD Barometric altitude

Reactive Mode 4 -- Unsafe Terrain Clearance Not In LandingMode

D Radio altitudeD Computed airspeedD Flaps position dataD Landing gear position data

Reactive Mode 5 -- Excessive Descent Below Glideslope

D Radio altitudeD Glideslope deviationD Localizer deviationD True track angleD Selected runway heading (if available)D Landing gear position dataD Backcourse input (if available)D G/S cancelD G/S inhibit (if available)D ILS tuned indication


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Situation Awareness Mode 6 -- Callouts

D Radio altitudeD Selected decision height (if this feature is selected)D Barometric altitude for minimum descent altitude (if this feature

is selected)D Landing gear position data

Excessive Bank Angle

D Radio altitudeD Roll angle

Windshear

D Inertial ground speedD AirspeedD Vertical speedD Inertial accelerationsD Attitude data (pitch and roll)D Left and right angles of attackD Slats position dataD Flaps position dataD Radio altitude


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ABNORMAL PROCEDURESUnder certain circumstances, the flightcrew may want to deactivatesome of the TAWS functions. This is described in the followingparagraphs.

CAUTION

THE FLIGHTCREW MUST EXERCISE EXTREME CAUTION INDETERMINING WHETHER OR NOT A FUNCTION OF THE TAWSSYSTEM SHOULD BE MANUALLY DEACTIVATED.

In some aircraft installations, it may be possible to suppress all of theTAWS aural annunciators. Consult the specific Aircraft Flight Manualfor details of the installation.

CPA Mode Manual DeactivationThe GCAM CPA mode can be manually deactivated by pushing theTERR INHIBIT switch. This disables only the CPA and terrain displayfunctions. The other TAWS functions operate normally.

NOTE: TheGCAMCPAmodemust bemanually inhibited by pushingthe TERR INHIBIT switch when landing at an airport whereACSS has confirmed that the database has an error whichwould result in a nuisance alert.

Reactive Modes (GPWS Modes) DeactivationMode 1 -- Mode 1 is always activated. This mode cannot bemanually deactivated.

Mode2 -- If theCPAmode is active (i.e.,TERRFAIL annunciatornot lit), Mode 2 is active only under certain conditions. ContactACSS if a list of these conditions is required. If the CPA mode isnot active, Mode 2 is automatically activated. In this case, if theaircraft is operatingwith low terrain clearance (less than 2500 ft),Mode 2 can be desensitized by manually activating the FLAP orGEAR OVERRIDE switches.

Mode 3 -- Mode 3 is automatically activated during takeoff andgo--around. This mode cannot be independently deactivated.

Mode 4 (Too Low Flaps, Too Low Gear, Too Low Terrain) --If the flightcrew is performing an approach with less flaps thanthe required landing flap configuration, the Too Low Flapscaution alert can be avoided by manually activating the FLAPOVERRIDE switch. The Too Low Gear caution alert can beavoided by manually activating the GEAR OVERRIDE switch.

NOTE: The Mode 4 Too Low Terrain caution alert is not affected bythe FLAP or GEAR OVERRIDE switches.


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Mode 5 -- Two different switches can be installed to preventunwanted Mode 5 alerts. Depending on the aircraft installation,one or both switches may be installed.

D G/SCANCELSwitch -- Pushing this switch cancels theMode5 alerts. The flightcrew may want to do this if they areperforming a visual or step--down approach. The Mode 5alerts remain canceled as long as the radio altitude isbetween 30 and 1,000 ft. As long as the Mode 5 alerts arecanceled, theG/SCANCEL (white) annunciator is lit. If Mode5 alerts are canceled with this switch, they are reactivatedwhen the radio altitude goes below 30 ft or above 1,000 ft.

D G/S INHIBIT Switch -- Pushing this switch inhibits the Mode5 alerts. The flightcrew may want to do this if they anticipatethat there will be excessive glideslope deviation during theapproach. The G/S INHIBIT switch must be manuallyde--selected to re--enable Mode 5 alerts.

EMERGENCY PROCEDURES

D Gear Up Landing -- If the aircraft must be landed with the gearretracted, push the GEAR OVERRIDE switch to inhibit alerts thatwould be generated by the improper landing configuration.

D Ditching or Landing Off Airports -- If the aircraft must be ditchedor landed away from an airport, push the TERR INHIBIT switch toinhibit the CPAmode and any alerts that would be generated by theterrain incursion.

NOTE: On installations without gear override, it may be necessary topull theTAWScircuit breaker to prevent alerts duringgear--uplanding or ditching.


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TAWS SELF--TEST

The TAWS self--test is initiated by pushing the TEST button on theTAWS control panel or through the onboard maintenance system(OMS) or central maintenance computer (CMC). The TAWS self--testalso tests the reactive windshear system (if activated) and the internalGPS module (if installed).

When the TAWS self--test starts, the system announces one of thefollowing over the speaker system:

D TERRAIN AWARENESS TEST START

D TERRAIN AWARENESS AND WINDSHEAR TEST START(if windshear is activated).

Also, the TAWS test pattern is displayed on the TAWS display (seeFigure 10--14).

Sample TAWS Display Test PatternFigure 10--14


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Sample TAWS Display Test Patterns with Eleview EnabledFigure 10--15


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The TAWS self--test function tests the following:

D All visual annunciators turn on for 1.5 seconds, off for 1.5 seconds,and then back on.

NOTE: If two or more annunciations share the same location onan EFIS, they will cycle during TAWS self--test.

— Terrain caution alert— Terrain warning— Windshear caution alert (if installed)— Windshear warning (if installed)— Terrain fail— Terrain inop— Windshear fail (if enabled)— Windshear inop (if enabled)— GPWS fail— GPWS inop— Glideslope (G/S) cancel— Steep approach (if enabled)— Terrain select— Flap override.

D Aircraft personality module (APM)

D Terrain database

D Obstacle database (if Obstacle Awareness is enabled)

D All external system inputs

D Internal parameters

D Internal GPS (if installed).

If the TAWS self--test passes, the system announces one of thefollowing over the speaker system:

D TERRAIN AWARENESS SYSTEM PASS

D TERRAIN AWARENESS AND WINDSHEAR SYSTEM PASS(if windshear is activated).


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If any part of the TAWS self--test fails, the system announces whichtest(s) failed over the speaker system and then announces one of thefollowing:

D TERRAIN AWARENESS LRU PASS

D TERRAIN AWARENESS TEST COMPLETE

D TERRAIN AWARENESS AND WINDSHEAR TEST COMPLETE(if windshear is activated).


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TAWS SELF--TEST ANNUNCIATIONS

For All Systems Pass Case:

Terrain Awareness Test Start -- Terrain Awareness System Pass --Terrain Awareness Test Complete

For T2CAS Fail (Terrain Inop Lamp Annunciated) Case:

Terrain Awareness Test Start -- Terrain Awareness System Fail --Terrain Awareness Test Complete

For External Input Fail (Input parameter SSM = FW or missing --Terrain Inop Lamp Annunciated) Case:

Terrain Awareness Test Start -- Terrain Awareness LRU Pass --Required External Input Failed -- Terrain Awareness System Fail --Terrain Awareness Test Complete

For External Input Not Available (Input parameter SSM = NCD/FT-- Terrain NA Lamp Annunciated) Case:

Terrain Awareness Test Start -- Terrain Awareness LRU Pass --Required External Input Unavailable -- Terrain Awareness SystemUnavailable -- Terrain Awareness Test Complete

Table 10--4 lists the possible self--test failures and the associated auralannunciator.

Failed Part of Self--Test Aural Annunciator

Overall system is not operational TERRAIN AWARENESSSYSTEM FAIL

One or more required externalsystem inputs unavailable

REQUIRED EXTERNAL INPUTUNAVAILABLE

One or more required externalsystem inputs are currently failed

ACTIVE EXTERNAL FAULTS

TAWS Self--Test Failure AnnunciatorsTable 10--4


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TAWS SELF--TEST ANNUNCIATIONS WITHWINDSHEAR

These annunciations are applicable only to those T2CAS installationsthat have the internal windshear function activated.

When self--test is activated with windshear functions installed, insteadof hearing “TERRAIN AWARENESS”, the pilot will hear “TERRAINAWARENESS ANDWINDSHEAR”. This is to let the pilots know thestatus of both the terrain and windshear functions.

TAWS SYSTEM EXTENDED SELF--TESTThe TAWS extended self--test gives information about the T2CASequipment serial numbers, TAWS maintenance pages, database partnumbers, aircraft configuration settings, system status, and systemfailures.

The aural extended self--test mode is entered by doing the following:

D Two button pushes within one 3--second period.

TAWS system maintenance pages are entered by doing the following:

D Run the normal TAWS self--test by pushing the TAWS TEST button.

D Push and hold the TEST button again within three seconds after thesystem announces the self--test is ended (either pass or complete).

The Standard Self--Test and the Aurals Extended Self--Test exitautomatically when testing is complete.

After entering the TAWS Maintenance Pages, a single button pushadvances to the next maintenance page.

To exit the Maintenance Pages, push and hold the TAWS TEST buttonfor 4 seconds or longer.


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NON--AIRBUS T2CAS SELF--TESTS

Cockpit Self--Test Discrete Activation

TAWS/RWS/GPSSelf TestOperations

Single buttonpush withinone 3--second

period

(Standard SelfTest)

Two buttonpushes withinone 3--second

period

(AuralsExtended Self

Test)

Single buttonpush is heldactive for > 3seconds

(MaintenanceReport)

Standard SelfTest YES YES YES

Active FaultAnnunciation YES YES

Past FaultAnnunciation YES

MaintenancePages

YES ifadditional

button push >=3 seconds

YES

NON--Airbus T2CAS Self--TestsTable 10--5


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TAWS and Reactive Windshear Annunciators


11. TAWS and Reactive WindshearAnnunciators

TYPES OF ANNUNCIATORS

Various aural alerts and visual annunciators are generated by TAWS toadvise the pilot of system status, caution, and warning conditions.

Aural Alert Priority

Alert priorities are determined by the level of urgency of the alert. Moreurgent situations have priority over less urgent situations.

Aural Alerts

Aural alerts can be generated by T2CAS for any of the cautions orwarnings generated by TAWS and reactive windshear functions. Thespecific messages are selectable from a list of several options throughthe aircraft configuration data (ACD) settings. Also, T2CAS can beconfigured to play the voices in either a male voice or a female voice.Table 11--1 lists the selectable aural alerts.

Condition Selectable Aural Alerts

OCPA Caution OBSTACLE AHEAD orCAUTION OBSTACLE

OCPA Warning – Pull--Up OBSTACLE AHEAD, PULL UPor OBSTACLE, OBSTACLE,PULL UP, PULL UP orWhoop, Whoop, PULL UP

OCPA – Avoid Obstacle AVOID OBSTACLE

CPA Caution TERRAIN AHEADorCAUTION TERRAIN

PDA Caution TOO LOW TERRAIN

Selectable Aural AlertsTable 11--1 (cont)


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TAWS and Reactive Windshear Annunciators11-2



CPA Warning -- Pull Up TERRAIN AHEAD, PULL UPorTERRAIN TERRAIN PULL UPPULL UPorWhoop Whoop, PULL UP

CPA Warning -- Avoid Terrain AVOID TERRAIN

Mode 1 Caution SINK RATE, SINK RATE

Mode 1 Warning Whoop Whoop, PULL UPorPULL UP, PULL UP

Mode 2 Caution TERRAIN, TERRAIN

Mode 2 Warning Whoop Whoop, PULL UPorPULL UP, PULL UP

Mode 3 Caution DON’T SINK, DON’T SINK

Mode 4 Caution TOO LOW, TERRAINorTOO LOW, FLAPSorTOO LOW, GEAR(These are not selectable. Theyare different messages fordifferent alert cases.)

Mode 5 Caution GLIDESLOPE

Mode 6 Bank Angle Alert BANK ANGLE, BANK ANGLE

Selectable Aural AlertsTable 11--1 (cont)


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Windshear Caution NothingorCAUTION WINDSHEAR

Windshear Warning WINDSHEAR, WINDSHEAR,WINDSHEARorSiren, WINDSHEAR,WINDSHEAR, WINDSHEAR

Selectable Aural AlertsTable 11--1


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Table 11--2 lists the TAWS and reactive windshear selectable auralalerts.


Callouts MINIMUMS, MINIMUMSMINIMUMSDECISION HEIGHTUNKNOWN DECISION HEIGHTAPPROACHING MINIMUMSAPPROACHING DECISION HEIGHTTWO THOUSAND FIVE HUNDREDTWENTY FIVE HUNDREDRADIO ALTIMETER VALIDONE THOUSANDFIVE HUNDRED500 ft toneFOUR HUNDREDTHREE HUNDREDTWO HUNDREDONE HUNDRED100 ft toneEIGHTYSIXTYFIFTYFORTYTHIRTY--FIVE35 ft toneTHIRTYTWENTY20 ft toneTEN

TAWS and Reactive Windshear Selectable Aural AlertsTable 11--2

Visual Alerts

The visual alerts generated by T2CAS can be configured for specificaircraft applications to drive various visual flight deck annunciators.T2CAS can either drive annunciator lights directly, or it can send controlinformation to the aircraft engine information and crew alerting system(EICAS), PFD, or MFD to display the annunciators on the appropriatedisplay location.


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Table 11--3 lists the typical TAWSand reactive windshear annunciators.

Annunciator Type Meaning

TERR Warning Predictive TAWS Warning (Pull Up orAvoid Terrain)

TERR Caution Predictive TAWS Caution

GPWS Warning Reactive GPWS Warning

GPWS Caution Reactive GPWS Caution

FLAP OVRD Status Flap position assumed correct forlanding

TERR Status Terrain map selected for display

G/S INHIBIT Status Mode 5 call out deactivated byflightcrew. Must be deselected tore--activate Mode 5.

GEAR OVRD Status Gear position assumed correct forlanding

G/S CANCEL Status Mode 5 alerts are suppressed by theflightcrew for radio altitude 30 to 1000feet. Automatic reset once above 1000feet.

TERR INHIB Status Predictive TAWS mode and terraindisplay are inhibited by the flightcrew

GPWS INOP Caution Reactive GPWS modes areunavailable

TERR INOP Caution Predictive TAWS mode and terraindisplay are unavailable

W/S INOP Caution Windshear detection mode isunavailable

W/S CAUTION Caution Increasing aircraft performancewindshear detected

W/S WARNING Warning Decreasing aircraft performancewindshear detected

TAWS and Reactive Windshear Visual AnnunciatorsTable 11--3


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12. Reactive Windshear System

The T2CAS incorporates a reactive windshear feature that isavailable as an optional part of the terrain awareness system, basedon aircraft requirement. The reactive windshear system meets therequirements of TSO C117a. The reactive windshear system doesnot provide climb guidance.

The reactive windshear system monitors factors that affect aircraftperformance on both takeoff and approach to identify the presenceof severe low--level, downburst/microburst--type windshear.

If these wind factors cause the aircraft performance to decrease toa predetermined level, audio and visual warnings are sounded,indicating to the crew that the aircraft’s net performance capabilityis deteriorating and rapidly approaching a critical state. The reactivewindshear systemmay also generate an optional caution alert whenan increasing--performance windshear is detected, thereby givingadvance warning of a possible decreasing--performance windshear.

Windshear is available for the non--Airbus configuration for Release8. Airbus T2CAS does not have the windshear function.


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Reactive Windshear System12-2


Figure 12--1 shows the reactive windshear system operation.

NOTE: Not all input signals are used by all systems.

Windshear DetectionFigure 12--1


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13. Acronyms and AbbreviationsAcronymsandabbreviations used in thismanual are defined as follows:

TERMS DEFINITION

ABV above

ACAS airborne collision avoidance system

ACD aircraft configuration data

ADC air data computerAFM aircraft flight manualAGL above ground level

AHRS attitude and heading reference system

AIM Airman’s Information Manual

ALT RPTG altitude reporting

AOA angle of attack

APM aircraft personality module

ASDB aircraft--specific database

ATC air traffic control

ATCRBS air traffic control radar beacon system

BLW below

CFIT controlled flight into terrain

CMC central maintenance computer

CPA closest point of approach(in the context of TCAS operation)

collision prediction and alerting(in the context of TAWS operation)

CRM cockpit resource management

CU computer units

DADC digital air data computer

DH decision height

DME distance measuring equipment

DMT diagnostic maintenance tool


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Acronyms and Abbreviations13-2


TERMS DEFINITION

ECAM electronic centralized aircraft monitor

EFIS electronic flight instrument system

EICAS engine information and crew alerting system

EIS electronic instrument system

EWD engine warning display

FAA Federal Aviation Administration

FAR Federal Aviation Regulations

FCU/MCP flight control unit/mode control panelFL flight levelFLS flight management landing systemFPA flightpath angle

fpm feet per minute

ft feet

FWS failure warning system

G/S glideslope

GA go--around

GCAM ground collision avoidance module

GDOP geometric dilution of precisionGLS GPS landing systemGPS global positioning system

GPWS ground proximity warning system

ICAO International Civil Aviation Organization

ICS intercom system

ID identification

ILS instrument landing system

IRS inertial reference system

ISA international standard atmosphere

kts knots


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TERMS DEFINITION

LRU line replaceable unit

MAA mountainous area airport

MDA minimum descent altitude

MEL minimum equipment list

MFD multi--function display

MLS microwave landing system

MOPS Minimum Operational Performance Standards

MSA minimum safe altitude

MSL mean sea level

MTCD minimum terrain clearance distance

MTL minimum trigger level

N normal

ND navigation display

NM nautical mile(s)

OCPA obstacle collision prediction and alerting

OMC onboard maintenance computer

OMS onboard maintenance system

PDA premature descent alert

PF pilot flying

PFD primary flight display

PNF pilot not flying

RA resolution advisory

RA FAIL resolution advisory failure

RAIM receiver autonomous integrity monitoring

RMS radio management system

RPTG reporting

RTCA radio technical commission for aeronautics

RVSM reduced vertical separation minimums


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Acronyms and Abbreviations13-4


TERMS DEFINITION

RWS reactive windshear system

SBAS space based augmentation system

SL sensitivity level

STBY standby

SWC stall warning computer

T2CAS terrain and traffic collision avoidance system

TA traffic advisoryTAL terrain advisory lineTA/RA traffic advisory/resolution advisory

TAWS terrain awareness warning system

TCAS traffic alert and collision avoidance system

TD FAIL traffic display failure

TED terrain eleview display

THD terrain hazard display

VFR visual flight rules

VS vertical speed

VSI FAIL vertical speed indicator failure

VSI/TRA vertical speed indicator/traffic and resolutionadvisories

WAAS wide area augmentation system

WX weather radar

XPNDR transponder


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Frequently Asked Questions


Appendix A


This appendix is a compilation of frequently asked questions andconcerns of pilots.

1. Is it possible to receive an RA at low altitude? If so, under whatconditions are low--altitude RAs to be flown?

Yes, this is possible! The following text explains how low radioaltitude RAs are flown.

CASE 1:

Radio Altitude: 1,450 ft AGL

Advisories not allowed: Increase descent RAs

At radio altitudes less than 1,450 ft AGL, all increase descent RAsare inhibited. That is, RAs requiring descents of 2,500 fpm or moreare inhibited. Below this radio altitude threshold, the maximumdescent rate TCAS may require is 1,500 fpm. If following anincrease descent RA which was initiated at a higher altitude, theRAwill most likely soften to a descend RA requiring a descent of only1,500 fpm as the aircraft passes below 1,450 ft AGL. Other RAs arepossible depending on the geometry of the encounter.

CASE 2:

Radio Altitude: Less than 1,000 ft AGL – descendingOrLess than 1,200 ft AGL – climbing

Advisories not allowed: Descend RAs

Descend RAs are inhibited when the aircraft is descending below aradio altitude of less than 1,000 ft AGL. If following a descend RAinitiated at a radio altitude above 1,000 ft, and the aircraft descendsbelow 1,000 ft, the RA will most likely soften to a do not climb RA.For example, if following a descend RA through 1,000 ft AGL, thetop half of the VSI/TRA display will display red, directing theflightcrew not to climb in order to remain clear of the higher altitudeintruder. Other RAs are possible depending on the geometry of theencounter.


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Frequently Asked QuestionsA--2


CASE 3:

Radio altitude: Less than 900 ft AGL – descendingOrLess than 1,100 ft AGL – climbing

Advisories not allowed: All RAs

Below these thresholds, theTCASswitches internally to theTAOnlymode. Therefore, RAs will not be generated or displayed. If an RAis active when the aircraft passes below the radio altitude threshold,the red RA square (J) will transition to an amber TA circle (F), anyred or green arcs which were displayed will be removed, but the“CLEAR OF CONFLICT” message will not be announced. TCASaural TA messages will be inhibited (no aural annunciators) below500 ft radio altitude +/-- 100 ft of hysteresis.

2. Is it a requirement to report that TCAS is installed on the aircraft?

Yes. When the flight plan is filed, the aircraft type and equipmentshould be indicated on the ICAO flight plan in Block 18 “Comments”or other appropriate blocks.

The following format example is for FAA flight plans.

T / Type Aircraft / Equipment

The preceding T and slash indicate the aircraft is TCASequipped. For example, the entry in Block 18 for a Boeing 757with TCAS (T / ) and both DME and altitude encodingtransponder ( / A) would be:

T / B757 / A

For example, the entry in Block 18 for an Ilyushin IL--62M withTCAS (T / ), and altitude encoding transponder ( / U) would be:

T / IL62M / U

Consult the FAA’s “Airman’s Information Manual” (AIM) for furtherinformation on specific Equipment Codes.

3. How is it decided which aircraft issues an RA?

Each TCAS equipped aircraft issues its own RA. The aircraft to firstinitiate theRA is considered the controlling TCAS for that RA. If bothaircraft issue RAs simultaneously, the aircraft with the numericallylower Mode--S address is the controlling TCAS.


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4. What is the maximum tracking range and what are the criteria fordisplay?

The FAA TCAS II system requires that aircraft be tracked forcollision avoidance purposes to a range of 14 NM. Aircraft beyondthis range are tracked and displayed to enhance pilots’ situationalawareness. In the T2CAS TCAS system, Mode--S traffic is availablefor display out to 80NMor greater. Mode--Cand/or Mode--A intruderaircraft are displayed only within 20 NM.

TCAS has the capability to actively track traffic at ranges up to80 NM or more. TCAS also has the capability to passively trackADS--B squitters on 1090MHz to amaximum range of 127NM if theprogram pin for this feature has been grounded, an appropriatedisplay is used, and path loss of power budgets meet sub MTLrequirements. Refer to Section 1 for specific range capabilities.However, the ability to display traffic at any range also depends onthe control panel RANGE switch settings and the type of displayused in the installation. Consult the aircraft’s Approved FlightManual for further information.

5. What is the cause of no bearing advisories? What should be done?

This does not occur in most aircraft with an ACSS system thatemploys dual directional or top directional/bottom omni TCASantennas. ACSS’s TCAS is able to operate solely from the topantenna with no degradation. The bank angle of the aircraft is notusually a problem with the ACSS TCAS.

It is unlikely but possible to have a no bearing advisory. Severalfactors will influence the frequency of occurrence of theseadvisories. The most common is the shading of the directionalantenna by the aircraft fuselage, wings, empennage, or propeller.This may occur at any bank angle.

Another possibility may be that the intruder’s transponder system isnot operating to its full capability. For example, its own fuselagewings, empennage, or propeller may be shading its antenna.

If no bearing advisories are received too frequently, consult theinstaller for possible solutions.


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6. What is the approximate size of the caution area for: a) two jetaircraft and; b) a jet aircraft and a typical light aircraft?

The caution area and the warning area are defined entirely by time,not distance. The time boundaries change with altitude andtherefore, a single value can not be given. The boundary for a TA is20 to 48 seconds; for an RA, it is 15 to 35 seconds. The sensitivitylevel (SL) determines the time boundary used at any given altitude.(Refer to Table 5--1.)

For two, typical, jet transport category aircraft, flying at 8,230meters(FL 270), the alarm time for an RA is 35 seconds (SL 7). If they areonadirect collision course, and if each is flying at 500 kts, theaircraftwill be approximately 9.8 NM apart when the RA is issued.

For a typical jet transport category aircraft and a typical light aircraftflying at 6,560 ft, the alarm time for an RA is 25 seconds (SL 5). Ifthe jet aircraft is flying at 200 kts, and the light aircraft is flying at 120kts, the aircraft will be approximately 2.2 NM apart when the RA isissued.

7. What is the amount of force required on the aircraft yolk to performan RA maneuver during high--speed flight versus low--speed flight?

The pitch change required is very precise and the pilot must besmooth in applying the corrective vector. The basic premise is thatthe 2 to 5 pitch changes required for an RA should occur over a3 to 5 second interval and should typically require only a 0.25 gmaneuver.

At 0.3 Mach, 1 of pitch change produces a 300 fpm change in thevertical speed. At 0.8 Mach, this same 1 of pitch change producesan 800 fpm change of vertical speed. The required RAmaneuversare so gentle that the passengers will be unaware anavoidance maneuver was accomplished.

A reversal may require going from +1,500 to –1,500 fpm. Thisshould beaprecise, smooth, and coordinatedmaneuver. Therefore,if in level flight at 0.8Mach, and an RA calls for a climb at 1,500 fpm,then the pilot should initiate a +2 pitch change to effect the climb.If a reversal occurs, then an incremental –4 pitch change will effecta descent at 1,800 fpm. Again, follow the RA guidance and initiatethe reversal precisely and gently with a 0.35 g maneuver.


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8. Why should an aircraft that is flying straight and level receive moreRAs than a climbing aircraft?

There are several possibilities. One is that there are simply moreaircraft flying near your altitude thannear the climb corridor. Anotheris that ATC must clear a larger area to establish a climb corridor. Itis also true that at lower altitudes there is more VFR traffic than athigher altitudes.

9. How is the aircraft’s performance capability taken into considerationwhen issuing climb RAs?

The altitude and performance limits of the aircraft are known by theTCAS system and are used in its logic. These limits are based onthe certified altitude envelope and on the aircraft’s performance invarious configurations. They are hard--wired into the installation aspart of the certification of the system for each aircraft type.Therefore, an increase climb RA is not commanded for your aircraftin the landing configuration if it is not able to perform the maneuverin that configuration. Instead, the RA might be either “MONITORVERTICAL SPEED” (to maintain current altitude) or “DESCEND,CROSSING DESCEND”. If both aircraft involved in the RA areTCAS equipped, the coordination between TCAS systems will giveappropriate maneuvers for both aircraft. The aircraft performancerequirements for certification of TCAS installations are contained inFAA Advisory Circular AC 20--131A.

10. In the event the intruder’s track or altitude information is lost duringan RA, the RA will terminate without a “CLEAR OF CONFLICT”announcement. What action should the pilot take?

Whenever an active RA is removed from the display or downgradedto a TA without the “CLEAR OF CONFLICT” announcement, thepilot must continue to establish andmaintain visual contact with theintruder, if at all possible, until the conflict is resolved, and then returnto ATC clearance altitude. This situation occurs under either of twocircumstances. First, if the altitude information from the intruder islost, the RA will revert to a TA. Second, if the TCAS is unable toreceive sufficient data from the intruder to establish andmaintain itstrack, the RA is removed after 6 seconds.


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11. On occasion, in high--traffic terminal areas, I have noticed somedistant traffic drop from my display as the density of closer trafficincreases. Is this normal?

Yes, this is normal. In areas with a high density of TCAS equippedaircraft, each TCAS reduces its interrogation range, power, and rateto avoid interferingwith normalATC radar interrogation. This has theeffect of reducing the TCAS surveillance range. Also, if more than50 aircraft are within range, TCASwill track the 50 closest or highestthreat aircraft. In this situation, traffic at the outer range of thesystem will be temporarily removed from view. When TCAS trafficin the immediate area is reduced, the long--range tracking willresume. To help prevent this situation from occurring, and unlessotherwise directed, pilots are encouraged to place the Mode--STransponder in the STBY mode by selecting STBY on themode--selector switch when the aircraft is not flying.

12. Are the display formats standardized between aircraft andequipment manufacturers?

The symbols used on the VSI/TRA displays are industry standards.The same symbols are generally found on VSI/TRAs as well as onelectronic navigation displays andweather radar displays.However,some minor exceptions exist.

D The ACSS VSI/TRA uses blue or cyan for other and proximatetraffic. Some manufacturers use white.

D On some aircraft, the self--test values are slightly different. Thetraffic is shown in the same location, but the relative altitudes areslightly different.

D Some versions of the ACSS VSI/TRA are capable of displayingvertical speed in meters per second.

D Some aircraft have additional features or enhancements.

In addition, several features of TCAS are optional and can beprogrammed based on the operator’s preference. Consult theaircraft’s Approved Flight Manual for the specifics of a particularinstallation.


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13. Are aircraft on the ground ever displayed as other or proximatetraffic?

Yes. TCAS classifies any aircraft with an operating transponder thatis not reporting its altitude to be “in the air”. Therefore, if an aircrafthas its altitude reporting function turned off, then TCASwill continueto appropriately track and display it, even when that aircraft isphysically on the ground. Also, when the TCAS host aircraft is morethan 1,650 ft AGL, additional aircraft may be displayed as certainaltitude--baseddisplay filtering algorithmsare suspended. For theseand other reasons, when parked on the ramp or at the gate, turn thetransponder mode control switch to the STBY position.


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Supplemental Information for TCAS Change 7


Appendix B

Supplemental Information for TCASChange 7

INTRODUCTION

This Appendix provides answers to the question, “Why doesn’t myTCAS display show all of the aircraft all of the time?” A flightcrewmember might be aware of aircraft traffic from cockpit radiocommunications, visual sighting, or information from ground ATCcontrollers. TCASmight be tracking intruder traffic, and legitimately notdisplaying this information or TCASmight not be tracking intruder trafficbecause of radar tracking limitations. Various reasons for not trackingor displaying intruder traffic on the TCAS display are discussed belowso operators will be more aware of the limitations of the TCAS system.

DETAILED EXPLANATION

Display Altitude Filtering

Information presented to the flightcrew on the TCAS display is filteredby a display altitude upper and lower limit usually set to +/-- 2,700 feetwhen in the NORMAL mode on the control panel. When in the ABOVEmode (if this mode is available on the control panel) the altitude limit isusually +7,000 to --2,700 feet. Likewise, when in the BELOWmode, thealtitude limit is usually --7,000 to +2,700 feet. All of these limits arecontrolled by the control panel. Some versions of the control panel willprovide different display limits and should be determined by examiningthe appropriate TCAS system user documentation for any particularaircraft. Traffic displayed on the TCAS display will be seen to beappearing and disappearing on and off of the display as each individualaircraft falls inside or outside of the display window.


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Supplemental Information for TCAS Change 7B--2


Display Traffic Numbering/Priority Filtering

The number of aircraft that can be displayed on any particular displayis limited to 31 maximum by ARINC 735, and can be less than 31depending on the type of display and how it is programmed for anyparticular aircraft installation. Traffic aircraft that are rated as a lowerpriority may be displayed only if the display is programmed to show alarge enough group of aircraft to include the lower priority traffic ofconcern. So if a particular aircraft is ratedas apriority 15and thedisplayis programmed toonly show14 aircraft, then theparticular aircraft ratedas priority 15 may not be displayed on the TCAS display. Intruderaircraft that are closer in rangewill generally be rated as a higher prioritythan targets further away, but not always. Other parameters, such asclosure rate or RA/TA status, may be used to calculate display priority,pushing other traffic down in priority and resulting in some traffic notbeing displayed. Additionally, depending on the display, higher prioritytraffic may not be shown when outside of the altitude filter windowdescribed above. This does not mean that TCAS does not track trafficnot being shown. TCAS surveillance will provide tracking for up to 50aircraft even though the display is showing 31 or less aircraft at anygiven moment. Thus, the protection afforded by TCAS is continuallyprovided for up to 50 individual aircraft evenwhenonly a few aircraft areshown on the display.

ATCRBS Intruder On Ground Filtering Logic

Tracking of ATCRBS transponders below 400 feet AGL is filtered outby the TCAS system per industry standards for both 6.04a andChange7 logic, and therefore these aircraft are not shown to the flightcrew onthe TCAS display.


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Antenna Patterning

Sometimes the signal strength of the received replies to TCAS, or of thetransmissions (interrogations) of the TCAS to intruder aircraft, dropbelow that necessary to track the transponder of the intruder. This canoccur when aircraft are banking such that the antenna pattern isshielded by the wing, engines, or fuselage of either the TCAS aircraftor the intruder aircraft, or when the range between the TCAS andintruder aircraft is far enough to reduce the signal strength below theminimum trigger level (MTL). When shielding occurs or the distance isgreat enough, a loss of tracking can occur, causing the track of thataircraft to drop after a six second coast in the case of normalsurveillance, and up to 10 seconds of coast for reduced surveillancetargets. Reduced surveillance targets are those greater than 3 NM orfurther than 60 seconds away from closest point of approach (CPA).Some aircraft only have one antenna on the bottom of the fuselage,making it more difficult to track these aircraft since their antenna can beshielded from TCAS even when maneuvering is not occurring. Also,some lower--end general aviation transponders do not transmit with thesame power levels as those required for air transport category aircraft,which also makes it more difficult to track these aircraft during antennapattern fading or at longer distances.

On Ground Aircraft Indication

Some aircraft have been found that indicate in transponder replies theyare on the ground when in fact they are actually flying at altitude. Someof these aircraft intermittently indicate they are on the ground andsomeindicate continually they are on the ground. TCAS does not track anyMode S aircraft are indicating that they are on the ground in theirtransponder replies, and consequently these aircraft will not bedisplayed no matter how close they come to own aircraft. While onlysmall numbers of these aircraft have been seen in the environment,they do exist and flightcrews should be aware of this and shouldcontinue visual surveillance at all times per normal flightrules/procedures.

Transponder Tracking/Secondary Surveillance

The TCAS only tracks aircraft with operating transponders. Militaryaircraft sometimes do not turn on their transponders and operators ofgeneral aviation aircraft sometimes forget to turn on their transponders.TCAS will not track aircraft with transponders that are inoperational orare turned off. flightcrews should be aware of this and should continuevisual surveillance at all times per normal flight rules/procedures.


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Interference Limiting

TCAS reduces its surveillance volume due to the number of TCASaircraft in the environment. This is to prevent interference with ATCground stations from exceeding 1% maximum, and to preventtransponder unavailability (due to TCAS interrogations) to less than1%maximum. The total amount of power available for surveillance whenin interference limiting and also when not in interference limiting hasbeen further reduced in Change 7 over that available in Change 6.04alogic perRTCADO--185a. RequiredChange 7surveillance logic furtherreducesTCASavailableRF powerwhen ownaircraft is near theground(below 2000 ft AGL), and severely reduces power when own aircraft ison the ground. When near or on the ground the total number of TCASunits detected on the ground as well as within 30 NM is used to reduceRF surveillance power. When airborne, the total number of airborneTCAS aircraft, and the distribution of airborne TCAS within 30 NM andwithin 6 NM is used to cause the required interference limitingalgorithms of TCAS to reduce its surveillance volume. The surveillancevolume of TCAS is reduced by restricting the amount of total RF powerthat TCAS can use in any given scan, and by reducing the sensitivityof the TCAS receivers. Mode S tracking in reduced surveillance, whereMode S intruders more than 3 NM away or beyond 60 seconds to theclosest point of approach, is used in Change 7 as specified in DO--185atomitigate the loss of longer range targets that would occur without thisor some type of more efficient use of TCAS--permitted total radiatedpower. Reduced surveillance Mode S intruders are interrogated onlyonce every 5 seconds, and are interrogated after normal surveillance,acquisition of new intruder aircraft, and ATCRBS interrogations havetaken place, if there is remaining RF power left to interrogate reducedsurveillance intruders. The bottom line here is that TCAS will trackwhatever it canwithin the restrictions of interference limiting and if thereis not enough power to go around, the longer range reducedsurveillance aircraft will be the first to be dropped from the display, asrequired by the industry standards of DO--185a. Some amount ofinterference limiting will occur in Change 7 TCAS when two or moreTCAS aircraft are detected within 6 NM.


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Aircraft that are furthest in range or are not considered as a threat (suchas “other” or “proximate” traffic, particularly when traffic is at longerranges) are dropped from the display due to interference limiting.Maximum interference limiting usually occurs at lower altitudes nearcongested airspace, where RA and TA warning times for short rangesto intruder traffic is usually sufficient becauseof the lower velocities andlow closure rates of traffic. Longer range traffic, or even short rangetraffic that is sufficiently separated in altitude from the host aircraft soas not to cause a TA or RA to occur, can be expected to suddenlydisappear from the display as a result of interference limiting. Droppeddisplay traffic often reappears, sometimes one or two aircraft at a time.The function of interference limiting is an RTCA DO--185A, MinimumOperational Performance Requirement, and as such is required of allmanufacturers of TCAS II equipment.

Multipath

Multipath, as implied by the name, is simply a way that a radio signalcan travel by more than one path to an intruder transponder or backfrom the intruder transponder to the TCAS aircraft. Multipath usuallyoccurs within 8,000 ft AGL or less since distances larger than this resultin enough signal loss to prevent multipath from occurring. In the caseof antenna patterning discussed above, where the direct path to theintruder antenna is shielded, it is possible for the TCAS transmissionsor intruder replies (or both) to travel down to the ground and reflect offof the ground back up to the intruder or TCAS. This will result in TCASmeasuring a greater distance to the intruder because the path lengthof the radar signal is longer than the direct path. When direct path andmultipath reflected paths are occurring intermittently it is possible todisplay two targets on the TCAS display. The multipath aircraft displaywill always appear further away in range than the actual aircraftbecause the multipath replies/interrogations have the greater pathlength between TCAS and the intruder. The actual aircraft will betracked closer to TCAS than the multipath track, and therefore theactual track will be first to cause any necessary TA or RA to be posted.Various filtering techniques are in place in the TCAS function in T2CASto discover and eliminate multipath tracking, but momentary multipathtracking for a period of a few seconds can still occur. Multipath can alsocause loss of tracking to occur. Loss of tracking due to multipath is theresult of reflected signals from the ground canceling out portions of thedirect path signal resulting in incomplete or very “noisy” signals thatcannot be decoded by TCAS. The loss of direct path usable signals isusually only temporary because aircraft geometries continue to changeaffecting antenna gains to the ground, and again multipath generallyonly occurs below about 8,000 ft AGL.


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ATC Radar Coverage

Sometimes TCAS will display intruder aircraft not seen by the ATCground stations. This can be the result of aircraft that are near theground shielded by terrain, below ATC radar coverage, or due to signalloss ormultipath at theATC radar site. Also, sometimesATCwill displayintruder aircraft not seen by TCAS for reasons discussed above. Otherreasons ATC might see an aircraft that TCAS might not includemarginal intruder aircraft transponder installations that are notperforming to specifications on pulse width, pulse rise and fall time,frequency, RF output power, transponder unavailability due totransponder reply rate limiting, and antenna coaxial losses, to name afew.

SUMMARY

There are many reasons why aircraft do not show up on the TCASdisplay, and as a result flightcrews should maintain proper visual seeand avoid techniques even though the TCAS display is providing someamount of situational awareness. The TCAS function in T2CAS hasbeen tested in the LosAngeles highdensity environment, and has beenproven to meet FAA and industry standards for TCAS surveillance.These standards require a greater than 95% track probability within5 NM range for ATCRBS intruders and within 10 NM for Mode Sintruders. The results of the T2CAS surveillance analysis are 99.5%track probability for ATCRBS intruders, and100% forModeS intruders.These results are average values where track coasting times are usedin computing track probabilities. For any particular intruder there existsa possibility the items discussed above can cause a particular intruderat any particular moment to not be tracked.


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Glossary


Appendix C

Glossary

The following glossary is provided as anaid to understanding theTCASsystem and its operation.

Advisory

An aural or visual message issued by TCAS to the pilot that containsinformation relevant to collision avoidance.

Alert

An indicator, either aural or visual, that quickly provides information tothe flightcrew about an abnormal situation. Alert is a generic term forany event--triggered indication to the pilot, including advisories,cautions, and warnings.

ATCRBS (Air Traffic Control Radar Beacon System)

A secondary surveillance radar system having ground--basedinterrogators and airborne transponders designed for operation inMode--A and Mode--C.

Caution Area

A volume of airspace that begins 20 to 48 seconds before the time anintruder aircraft is predicted to enter the TCAS aircraft’s collision area.(Refer to Figure 2--2.) TCAS provides TAs to facilitate visual acquisitionof other aircraft entering this airspace.

CFIT (Controlled Flight Into Terrain)

An accident or incident in which an aircraft, under the full control of thepilot, is flown into the terrain, obstacle, or water.

Collision Area

A volume of three--dimensional airspace surrounding a TCAS--equipped aircraft, that varies in size based upon the closure rate of anintruder aircraft with the TCAS--equipped aircraft. TCAS is designed toprovide RAs to avoid other aircraft that might enter this airspace.


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GlossaryC--2


Decision Height

With respect to the operation of an aircraft, means the height at whicha decision must be made, during an ILS or PAR instrument approach,to either continue the approach or to execute a missed approach.

Intruder

An aircraft equipped with an operating ICAO ATCRBS or Mode--STransponder that is within the surveillance range tracked by TCAS.

Minimum Descent Altitude

The lowest altitude, expressed in feet above mean sea level, to whichdescent is authorized on final approach or during circle--to--landmaneuvering in execution of a standard instrument approachprocedure, where no electronic glideslope is provided.

Missed Approach

An aborted approach resulting in an immediate climb and / or turnfollowed by a route directly to a missed approach point.

Mode--A

A type of ATCRBS transmission that returns the selected aircraftidentity code (the “4096” code) when interrogated. Mode--A responsescontain no altitude information. Therefore, no TCAS system operatesin Mode--A since it is not possible to determine an RA from only aMode--A reply.

Use of the term “Mode--A” tomean “a transponder replywithno altitudedata” is common, but it can bemisleading in a narrow, technical sense.Transponders with the capability to turn altitude reporting off do notrevert to only Mode--A operation. Rather, they continue to provideMode--C responses, but with no altitude data. When operating in thismanner, the transponder continues to provide bothMode--A replies (theselected “4096” code) andMode--C replies with no altitude data. (Referto Mode--C below.)

NOTE: In thismanual, “Mode--A” is generally used in thebroadsenseto refer to a transponder that is providing Mode--C replieswith no altitude data.


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Glossary


Mode--C

A type of ATCRBS transmission that has the capability of replying withaircraft altitude when interrogated. Mode--C replies without altitudeinformation are possible when the altitude encoding systemmalfunctions, is disabled, or is absent. A Mode--C reply does notcontain the aircraft identity code (“4096” code); only the altitude data istransmitted.

Use of the term “Mode--C” to mean “a transponder reply with altitudedata” is common, but it can bemisleading in a narrow, technical sense.Transponders with the capability to turn altitude reporting off do notcease responding to Mode--C interrogations. Rather, they continue toprovide Mode--C responses, but with no altitude data. Typical ATCradars will alternately request Mode--C and Mode--A replies in order toobtain both the identity code and the altitude. TCAS requests onlyMode--C replies because the Mode--A reply contains no usefuladditional data for calculating TAs and RAs.

NOTE: In this manual, “Mode--C” is generally used in the broadsense to refer to a transponder that is providing Mode--Creplies with altitude data.

The range of an aircraft is calculated by the time of arrival of theinterrogation reply. The calculated range is the straight--line distance tothe aircraft in 3--dimensional space. This is often referred to as “slant”range and is similar in nature to the distance displayed on a DME(distance measuring equipment) display. When Mode--C altitudeinformation is received, the displayed range is corrected to providehorizontal range on the display. Therefore, the display of traffic withoutaltitude datamay bedeceiving. For example, anaircraft without altitudedata may be at a very low altitude while the TCAS aircraft is at a high,flight level altitude. This traffic may be displayed laterally when in factit is almost directly below the TCAS aircraft.

TCAS is able to compute the altitude difference between itself and anintruder using the altitude information contained in the Mode--C reply.This results in a more accurate display of intruder aircraft altitude andrange.

Mode--S

A type of secondary surveillance radar transmission that permits directinterrogation of the transponder from the ground or from the air. EachMode--S Transponder equipped aircraft has a unique ICAO registeredaddress by which the transpondermay be selectively interrogated. Themode also supports limited, two--way data communication between theaircraft and the interrogating station.


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GlossaryC--4


Mode--S is the means through which one TCAS equipped aircraftcoordinates avoidance strategieswith another TCAS equippedaircraft.

Nuisance Alert

An inappropriate alert received during normal safe procedures.

Other Traffic

Any transponder--replying aircraft within the selecteddisplay range thatis not classified as either proximate traffic or as an intruder requiring aTA or an RA is displayed as other traffic.

PDA -- (Premature Descent Alert)

This alert occurs if the aircraft is below an acceptable altitude based onthe aircraft flight phase.

Proximate Traffic

Any transponder--replying aircraft within the horizontal range capabilityof the display, and within 1,200 ft vertically of the TCAS aircraft isdisplayed as proximate traffic. This traffic is displayed in conjunctionwith a TA or an RA when the TRAFFIC switch is set to AUTO, or at alltimes when the TRAFFIC switch is set to ON.

Resolution Advisory (RA)

An aural message and visual display instructing the pilot on actions tobe taken or avoided in order to maintain or increase vertical separationrelative to an intruding aircraft. These advisories are designed to occurwhen an intruder’s predicted flight path is within 15 to 35 seconds ofentering the TCAS aircraft’s collision area. RAs fall into two generalcategories.

D Corrective advisory: An RA that instructs the pilot to achieve ormaintain a specified vertical speed as indicated by a green arc onthe VSI/TRA.

D Preventive advisory: An RA that instructs the pilot to avoid certainvertical speed as indicated by the red arc on the VSI/TRA. There isno green arc on a preventive RA.

TCAS Function in T2CAS

A specific product of ACSS that meets and exceeds the requirementsof the United States Federal Aviation Administration’s TCAS IIspecification. Refer to Section 1, Figure 5--1, and Table 5--1 for specificperformance capability of the TCAS function in the T2CAS LRU.


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Glossary


TCAS 2000

A specific product of ACSS that meets and exceeds the requirementsof the United States Federal Aviation Administration’s TCAS IIspecification.

TCAS II

A) A United States Federal Aviation Administration developed TrafficAlert and Collision Avoidance System designed to reduce thenumber of mid--air collisions. The “II” designates a system that iscapable of providing RAs in the vertical plane. This systeminterrogates and receives replies from airborne radar beacontransponders, computes the tracks of those aircraft, determines ifany of the tracks will pose a threat to the TCAS II aircraft, and issuesTAs and RAs to the flightcrew. All FAA TCAS II systems arepresently required to meet Change 6.04a and are upgradable toChange 7.0.

B) A specific product of ACSS that meets and exceeds therequirements of theUnited States Federal Aviation Administration’sTCAS II specification.

Traffic Advisory (TA)

An advisory issued to the pilot when an intruder’s predicted flight pathis within 20 to 48 seconds from entering the TCAS aircraft’s collisionarea. TCAS issues TAs to alert the flightcrew of possible threats to thesafety of the flight.

Warning Area

An area of three--dimensional airspace that begins 15 to 35 secondsprior to the time the intruder is predicted to enter the TCAS aircraft’scollision area.

Weakening Advisory

The “ADJUST VERTICAL SPEED, ADJUST” advisory is provided tothe pilot to facilitate reduction of the clearance deviation, minimizedisruption of ATC and reduce altitude excursions.


8000264--001Rev 1 Jul 15/2004

GlossaryC--6




8000264--001Rev 1 Jul 15/2004 D--1

Electronic Flight Instrument Displays for TCAS


Appendix D

Electronic Flight InstrumentDisplays for TCAS

BOEING DISPLAYS

ID--8000312


8000264--001Rev 1 Jul 15/2004

Electronic Flight Instrument Displays for TCASD--2


BOEING DISPLAYS (CONT)

ID--8000313

ID--8000314


8000264--001Rev 1 Jul 15/2004 D--3




ID--8000315


8000264--001Rev 1 Jul 15/2004




ID--8000316

ID--8000317


8000264--001Rev 1 Jul 15/2004 D--5




ID--8000318

ID--8000319

GRH0835.46.3 NM

Z


8000264--001Rev 1 Jul 15/2004



AIRBUS DISPLAYS

ID--8000320

ID--8000321


8000264--001Rev 1 Jul 15/2004 D--7



AIRBUS DISPLAYS (CONT)

ID--8000322

ID--8000323


8000264--001Rev 1 Jul 15/2004




ID--8000324

ID--8000325


8000264--001Rev 1 Jul 15/2004 D--9




ID--8000326

ID--8000327


8000264--001Rev 1 Jul 15/2004




ID--8000328

ID--8000329


8000264--001Rev 1 Jul 15/2004 D--11




ID--8000330

ID--8000331


8000264--001Rev 1 Jul 15/2004




ID--8000332

ID--8000333


8000264--001Rev 1 Jul 15/2004 D--13




ID--8000334

ID--8000335


8000264--001Rev 1 Jul 15/2004




ID--8000336

NAV TCAS FAULT

ID--8000337

TCAS STBY

ID--8000338


8000264--001Rev 1 Jul 15/2004 D--15



MD--11 DISPLAYS

ID--8000339

ID--8000340


8000264--001Rev 1 Jul 15/2004



MD--11 DISPLAYS (CONT)

ID--8000341


8000264--001Rev 1 Jul 15/2004 E--1

Bibliography


Appendix E

Bibliography

AC 20--131A Airworthiness and Operational Approvalof Traffic Alert and Collision AvoidanceSystems (TCAS II) and Mode--STransponders, United States FederalAviation Administration.

AC 90--48C Pilot’s Role in Collision Avoidance, latestrevision, United States Federal AviationAdministration.

AC 120--55A Air Carrier Operational Approval and Useof TCAS II, latest revision; United StatesFederal Aviation Administration.

AIM Airman’s Information Manual, latestversion, United States Federal AviationAdministration.

RTCA DO--181b Minimum Operational PerformanceStandards for Air Traffic Control RadarBeacon System/Mode--Select(ATCRBS/Mode--S) AirborneEquipment,RTCA, Inc.

RTCA DO--185a Minimum Operational PerformanceStandards for Traffic Alert and CollisionAvoidance System (TCAS) AirborneEquipment, Changes 1 through 6 andChange 6.04a, RTCA, Inc. and Change7.

Characteristic 718--4 Mark 3 ATC Transponder, ARINC,Incorporated.

Characteristic 735--2 Traffic Alert and Collision AvoidanceSystem (TCAS), ARINC, Incorporated


8000264--001Rev 1 Jul 15/2004

BibliographyE--2


OTA--SET--431 “Safer Skies with TCAS – A SpecialReport: Traffic Alert and CollisionAvoidance Systems”, Office ofTechnology Assessment, Washington,D.C., US Government Printing Office,February, 1989


8000264--001Rev 3 Jun 15/2007 F--1

Airbus--Specific Applications


Appendix F


AIRBUS T2CAS PART NUMBERS

The Airbus T2CAS part numbers are listed in Table F--1.

Airbus T2CAS Part Numbers

9000000--10110 (STD #1)

9000000--11111 (STD #2)

Airbus T2CAS Part NumbersTable F--1

NO ALTITUDE CALLOUTS

For Airbus configurations, T2CAS does not generate altitudecallouts. It is done by failure warning systems ( FWS ).

WIND EFFECTS

With a tailwind, the climb rate of the aircraft does not change.However, the ground speed increases, thus reducing the climbgradient. This function compensates for this effect by factoring inthe reduced climb performance in forward looking terrain clearancecomputations.

Basic GPWS Mode Specific for Airbus

In earlier versions of T2CAS, GPWS Mode 1 was inactive when thepredictive mode forward looking function was active. For Airbus STD#2, Mode 1 is always ON.

In the event of erroneous terrain cell detection, position errordetection, or altitude error detection, the Mode 2 alerting function willbe activated. This is done when perceived terrain is higher than theterrain database.

Mode 2 will only be active when the system detects a discrepancybetween the calculated terrain height (based on radio altitude andMSL altitude) and the terrain database height at the current GPS orFMS position.


8000264--001Rev 3 Jun 15/2007

Airbus--Specific ApplicationsF--2


Mode 1 and Mode 2 will continue to be active when the forwardlooking function is inoperative or inhibited, just as it is in the previous(STD #1) version.

The Mode 4 (4A and 4B) is inhibited in APPR phase if both flaps andgear are in landing configuration OR in TO Phase (anyconfiguration).

Mode 4 (4a and 4b) will be inhibited if all of the following are true:

D The flaps are in the landing configuration.

D The gears are in the landing configuration.

D The radio altitude is lower than 500 ft (had been 250 ft).

D The Mode 4 (4a and 4b) stops being inhibited only if the radioaltitude is greater than 500 ft.

D Gear and flaps speed levels are pre--selected.


8000264--001Rev 3 Jun 15/2007 F--3



Too Low Terrain/Gear/Flaps Envelope for Mode 4 (Airbus)Figure F--1


8000264--001Rev 3 Jun 15/2007



Flight Management Landing System (FLS)

D FLS allows non--precision approaches to be flown the same wayas ILS, MLS and GLS provided the procedure is published asstraight--in with a single glideslope.

D FMS/GPS based approach capability mimics an ILS but without aground--based glideslope beam.

D Mode 5 alert is inhibited when the ILS indicates an FLS orLOC/FLS approach is active. Often aircraft moves away frompseudo--glide generated by FLS, therefore a need to inhibit Mode5 in such conditions to avoid spurious alerting.

D The crews have the capability to fly the non--precision approacheither using the autopilot or the flight director, or manuallyfollowing the FLS pseudo--deviation data.

Airbus -- Pushbutton Switches, GPWS Control Paneland ECAM Messages

T2CAS--TAWS Controls (LR)Figure F--2

T2CAS--TAWS Controls (SA)Figure F--3


8000264--001Rev 3 Jun 15/2007 F--5



GPWS/FLAP MODE Pushbutton Switch

The pushbutton switch, when pressed (in) (white OFF legend on),overrides flap abnormal condition input and generates the GPWSFLAP MODE OFF message (green) in the memo area of the EWD.

GPWS/G/S MODE Pushbutton Switch

The pushbutton switch, when pressed (in) (white OFF legend on),inhibits the glideslope mode.

GPWS/SYS Pushbutton Switch

When the SYS pushbutton switch is pressed (OFF legend on), allground proximity alerts (Modes 1 to 5) are inhibited (visual andaudio) and no T2CAS--TAWS self--test is possible.

GPWS/TERR Pushbutton Switch

When the TERR pushbutton switch is pressed (OFF legend on ), theforward looking and terrain hazard display (predictive) functions areinhibited (visual display and audio inhibition). It generates the TERROFF message (green in cruise or amber otherwise) in the memoarea of the EWD. At this point, normal GPWS protection remains ineffect.

GPWS/LDG FLP 3 Pushbutton (SA only)

This button is pressed when a landing in flap configuration 3 isintended. When pressed, the white ON legend is illuminated.

PULL UP/GPWS (CAPT and F/O) PushbuttonSwitches

These pushbutton switches have two functions when pressed (in):

— they cancel the glideslope alert, or

— they initiate the self--test sequence if the aircraft is on ground.

TERR ON ND (CAPT and F/O) Pushbutton Switches

These pushbutton switches allow the crew to select or deselectterrain display on ND. The ON legends indicate that terrain data isdisplayed on ND (following manual or automatic pop--up selection).

Other Indication (ECAM only)

When an input required for the forward looking function and terrainhazard display operation is considered invalid or unavailable (not afault), the following memo is displayed on ECAM:


8000264--001Rev 3 Jun 15/2007



EWD : TERR STBY (green). (See Figure F--4.)

In such a case, Modes 1 and 2 are reactivated.

Messages Displayed on EWD SDFigure F--4

An ECAM Message of Terrain Standby can occur when an externalinput can not provide the required data but the external signal does notindicate a failure. An example is a GPS input not available due torotation of satellites.


8000264--001Rev 3 Jun 15/2007 F--7



Terrain Hazard Display for Airbus Configuration

This operational function enhances situational awareness byproviding an image of terrain--related hazardous situations in front ofthe aircraft on existing flight deck displays.

The figure below does not show the exact colors that appear duringan alerting condition. Terrain background coloration is computed bycomparing terrain elevation with a reference altitude.

The reference altitude is the current A/C altitude while in level flightor during a climb. In descent, in order to provide some anticipatedsituational awareness, the reference altitude is projected 30s aheadon the FPA, then extended horizontally as shown below. (See FigureF--5.)

Background ComputationFigure F--5

NOTE: The Airbus reference altitude is based on the aircraft flightpath for negative flight path angles. For positive flight pathangles, the reference altitude is based on the aircraft’sactual altitude.

The coloration is consistent with the first Airbus TAWS installationcolor scheme.

D Terrain above reference altitude -- MTCD : Red and yellow

D Terrain below reference altitude -- MTCD : Green

D Terrain hazard sweeping starts in the middle of the screen andsweeps to both sides of the screen

D Weather radar sweeping starts at one side and sweeps to theother.


8000264--001Rev 3 Jun 15/2007



Terrain within 400 ft of the nearest airport is not shown (at maximumdistance of 15 NM from nearest runway).

Table F--2 lists the colors applicable to terrain elevation and terrainalerts.

Color Terrain Elevation

Solid Red Terrain threat area – warning

Solid Yellow Terrain threat area – caution

High density red dots Terrain more than 2,000 ft aboveaircraft altitude

High density yellow dots Terrain between 1,000 and 2,000 ftabove aircraft altitude

Low density yellow dots Terrain altitude that is 600 ft below to1,000 feet above aircraft altitude

High density green dots --1,000 ft < Terrain < --600 ft

Low density green dots --2,000 ft < Terrain < --1,000 ft

Magenta No terrain data available

Black No significant terrain.

Yellow Terrain Caution

Red Terrain Warning

Black with red cross hatch Avoid Terrain

Airbus Terrain Display Colors for Various Terrain ElevationsTable F--2

Premature Descent Alert (PDA)

The PDA is based on a combination of forward looking sensordetection and the ability of the aircraft to level off at a safe heightabove terrain.

The PDA function uses information from a navigation source, radioaltitude, and the onboard database. The PDA function (forwardlooking) also complements basic Mode 4 protection by sending analert during a landing situation.

D The PDA “Too Low Terrain” alert occurs when the aircraft isdescending and the terrain obstacle is below rather than in frontof the aircraft.


8000264--001Rev 3 Jun 15/2007 F--9



D No display alert area is associated with a PDA alert.

D No display pop--up will be generated for a PDA alert.

D The PDA is not limited by distance to airports.

D PDA alerting can be inhibited by selecting the terrain inhibitswitch.

Airbus Background Terrain Display on NDs

When no forward looking function alert is active, TERR (cyan)indication is displayed in the bottom right corner. (See Figure F--6.)

Terrain Background DisplayFigure F--6

Terrain Alerts Display

When a predictive mode (forward looking function) alert is triggered,an automatic terrain image is displayed on both NDs (“Pop--Up”activation), with terrain threatening appropriately depicted. TheTERR AHEAD text message displays on the bottom right corner.(See Figure F--7.)


8000264--001Rev 3 Jun 15/2007



TERR AHEAD Caution IndicatorFigure F--7

During caution alerts, the TERR AHEAD (yellow) indicator isdisplayed in the bottom right corner. Terrain obstacles are displayedin solid yellow on the terrain display. Figure F--8 shows the TERRAHEAD warning.

Terrain Ahead Pull Up IndicatorFigure F--8

During warning alerts, the TERR AHEAD (red) indicator is displayedin the bottom right corner. Terrain obstacles are displayed in solidred on the terrain display.


8000264--001Rev 3 Jun 15/2007 F--11



Figure F--9 shows an example of a TERR AHEAD indicator to avoida terrain hazard.

Avoid Terrain IndicatorFigure F--9

During an AVOID TERRAIN alert, the TERR AHEAD (red) indicatoris displayed in the bottom right corner. The “Avoid Terrain” aural alertis preceded at least once by “Terrain Ahead Pull Up”. Terrainobstacles are displayed in red with black cross--hatching on theterrain display.

Airbus Maintenance Interface to the OMC

The T2CAS supports an interface to the Onboard MaintenanceComputer (OMC). The OMC is used by the maintenance computerto examine the status of various LRUs and modules onboard theaircraft to facilitate correction of failures. Table F--3 lists the optionsfor the OMC.


8000264--001Rev 3 Jun 15/2007



OMSSelf--TestInput

Activation Flight Deck Self--Test Discrete Activation

TAWS/RWS/GPSSelf--TestOperations

SelectSTART

TEST fromthe OMSTAWS TestSetup Page

(StandardSelf--Test)

Singlebutton

push withinone

3--secondperiod

(StandardSelf--Test)

Two buttonpushes

within one3--secondperiod

(ExtendedSelf--Test)

Single buttonpush is heldactive for >3 seconds

(MaintenanceReport)

StandardSelf--Test

YES YES YES YES

Active FaultAnnunciation

YES YES

Past FaultAnnunciation

YES

MaintenancePages

YES ifadditionalbutton push

>= 3seconds

YES

Airbus Maintenance Interface to the OMCTable F--3


8000264--001Rev 3 Jun 15/2007 F--13



Figure F--10 shows the locations of the cockpit indicators.

Cockpit Indications (A320 Family)Figure F--10

Pilot--Initiated TAWS Go / No Go Self--Test on Ground

When activating the self--test from the glare shield :

D Press and release the PULL UP/GPWS button within 3 seconds.

D Aural test messages begin with “Terrain Awareness Test Start”,“Terrain Awareness System Pass” and ends with “TerrainAwareness Test Complete”.

D The TAWS test pattern is displayed on both NDs with ON ND greenlamps illuminated. The following lamps are turned on (activated) for4.0 seconds and then turned off (deactivated) for 2.0 seconds andthen on (activated) for approximately 4.0 seconds and then turnedoff (deactivated):

- TERR FAULT

- GPWC SYS FAULT

- GPWS Caution (on side 1 and 2)

- PULL UP Warning (on side 1 and 2).


8000264--001Rev 3 Jun 15/2007



D Report to maintenance staff when failure messages annunciated.

When activating the self--test from the MCDU :

D Select LRU as GPWS.

D Press Self--Test button.

D Follow instructions on screen.

D Report to maintenance staff if failures annunciated.

Figure F--11 shows the self--test pattern.

Self--Test PatternFigure F--11


8000264--001Rev 3 Jun 15/2007 F--15



Airbus Self--Test Aurals

For All Systems Pass Case:

Terrain Awareness System Test Start -- Terrain Awareness SystemPass -- Terrain Awareness Test Complete

For T2CAS Fail (Terrain Inop Lamp Annunciated) Case:

Terrain Awareness System Test Start -- Terrain Awareness System Fail-- Terrain Awareness Test Complete

For External Input Fail (Input parameter SSM = FW or missing --Terrain Inop Lamp Annunciated) Case:

Terrain Awareness System Test Start -- Terrain Awareness LRU Pass-- Required External Input Failed -- Terrain Awareness System Fail --Terrain Awareness Test Complete

For External Input Not Available (Input parameter SSM = NCD/FT-- Terrain NA Lamp Annunciated) Case:

Terrain Awareness System Test Start -- Terrain Awareness LRU Pass-- Required External Input Unavailable -- Terrain Awareness SystemPass -- Terrain Awareness Test Complete


8000264--001Rev 3 Jun 15/2007





8000264--001Rev 4 Dec 31/2008 G--1

Color Schemes


Appendix G

Color Schemes

The following section is provided as an aid to understanding alternateTerrain Display Color configurations.

Terrain Display Color Schemes

Color Scheme 1, defined in Table G--1 below, is an alternative to theACSSColor Schemediscussed inChapter 10. TableG--1 describes theterrain display patterns for Color Scheme 1, as shown in Figures G--1and G--2.

Terrain Elevation(typical values) Terrain Color Dot Density

2,000 ft or more abovethe aircraft referencealtitude

Red High

1,000 ft to 2,000 ftabove the aircraftreference altitude

Yellow High

0 ft to 1,000 ft abovethe aircraft referencealtitude

Yellow Low

Maximum of (500 ft,MTCD) below theaircraft referencealtitude to the aircraftreference altitude

Yellow Low

Maximum of (500 ft,MTCD) to 1,000 ftbelow the aircraftreference altitude

Green High

1,000 ft to 2,000 ftbelow the aircraftreference altitude

Green Low

Alternate Terrain Display Patterns for Various ElevationsTable G--1 (cont)


8000264--001Rev 4 Dec 31/2008

Color SchemesG--2


Terrain Elevation(typical values) Dot DensityTerrain Color

2,000 ft or greaterbelow the aircraftreference altitude

Black N/A

Invalid terrain cell Magenta Solid

Terrain Caution Yellow Solid

Terrain Warning Red Solid

Avoid Terrain Red/Black Black with redcross--hatch

NOTES: 1. The exact altitudes at which certain colors appearcan be configured by ACSS. Refer to the AFM, AFMsupplement, or this Appendix for the settings on youraircraft.

2. If the aircraft is within 15 Mn of the nearest airport,terrain with elevation less than the nearest runwayelevation + 400 ft is displayed as Black.

Alternate Terrain Display Patterns for Various ElevationsTable G--1


8000264--001Rev 4 Dec 31/2008 G--3

Color Schemes


Alternate Terrain Color Scheme 1 DisplayFigure G--1


8000264--001Rev 4 Dec 31/2008

Color SchemesG--4


Alternate Terrain Color Scheme 1Figure G--2


8000264--001Rev 3 Jun 15/2007

IndexIndex--1


IndexA

Abbreviations, 13-1Abnormal procedures, 10-25Acronyms, 13-1Airbus applications, F--1maintenance interface to theOMC, F--11

premature descent alert, F--8self--test aurals, F--15terrain alerts display, F--9terrain hazard display, F--7

AnnunciationsTAWS Self--test Annunciations,10-31

TAWS Self--test Annunciationswith Windshear, Windshear,10-32

Annunciators, 4-1, 4-2failure annunciators, 4-3mode annunciators, 4-1self--test annunciators, 4-6windshear visual annunciators,11-5

Aural alerts, 11-1pilot reactions, 9-8

Aural messages, 3-18clear of conflict, 3-21corrective resolution advisories,3-19

corrective, weakening orrestrictive advisories, 3-21

increased strength or reversedcorrective advisories, 3-20

preventive or weakeningadvisory, 3-18

resolution advisories, 3-18traffic advisory, 3-18windshear selectable aural alerts,11-4

B

Bibliography, E--1

C

Cautions”don’t sink”, 9-28”too low flaps”, 9-30”too low gear”, 9-30”too low terrain”, 9-30bank angle limits, 9-34clearance sensor, 9-14envelope boundaries, 9-15excessive descent, 9-32excessive descent rate, 9-23excessive terrain closure rate,9-26

glideslope, 9-32pilot reactions, 9-8sink rate, 9-24terrain alert, 9-20terrain envelope, 9-18

Cold weather operations, 9-39Color Schemes, G--1Controls and displays, 3-1, 3-2aural messages, 3-18display, 3-7example of VSI/TRA with trafficdisplayed, 3-17

resolution advisory vertical speedguidance, 3-13

traffic display symbols, 3-14Corrective resolution advisories, 7-4response to a climb RA, 7-4response to a corrective reduceclimb RA, 7-8

response to a corrective reducedescent RA, 7-9

response to a crossing climb RA,7-6


8000264--001Rev -- Feb 06/2003

IndexIndex--2


Index (cont)

response to a crossing descendRA, 7-7

response to a descend RA, 7-5

D

Description, 1-1global positioning system, 1-5reactive windshear system, 1-5terrain awareness warningsystem, 1-4

traffic alert and collisionavoidance system, 1-2

Display, 3-7modified weather indicator, 3-12primary flight and navigationdisplays, 3-10

VSI/TRA display, 3-7Displays, D--1Boeing displays, D--1MD--11 displays, D--15

E

Eleview display, Terrain eleviewdisplay, 10-20

Emergency procedures, 10-26Example of VSI/TRA with trafficdisplayed, 3-17no bearing intruder, 3-18other traffic, 3-17proximate traffic, 3-17resolution advisory, 3-17traffic advisory, 3-17

F

Flight crew responsecockpit resource management,6-6

expected flightcrew response,6-5

pilot responsibilities, 6-1Flightcrew response, 6-1, 6-2Frequently asked questions, A--1

G

Glossary, C--1advisory, C--1alert, C--1ATCRBS (air traffic control radarbeacon system), C--1

caution area, C--1CFIT (controlled flight intoterrain), C--1

collision area, C--1decision height, C--2intruder, C--2minimum decent altitude, C--2missed approach, C--2mode--A, C--2mode--C, C--3mode--S, C--3nuisance alert, C--4other traffic, C--4PDA, C--4proximate traffic, C--4resolution advisory (RA), C--4TCAS 2000, C--5TCAS II, C--5traffic advisory (TA), C--5warning area, C--5


8000264--001Rev -- Feb 06/2003

IndexIndex--3


Index (cont)

weakening advisory, C--5

I

Introduction, 1-1, 1-2description, 1-1purpose, 1-1

L

Logic parameters, 5-1, 5-2alarm time, 5-4example calculations, 5-4protected area, 5-4sensitivity level, 5-3vertical threshold, 5-4

O

Operating mode requirements,10-22

Operating modes, GPWS, 9-23mode 1 -- excessive descent rate,9-23

mode 2 -- excessive terrainclosure rate, 9-26

mode 3 -- loss of altitude aftertakeoff, 9-28

mode 4 -- unsafe terrainclearance not in landing mode,9-30

mode 5 -- excessive descentbelow glideslope, 9-32

mode 6 -- excessive bank angleand altitude callouts, 9-34

Operating procedures, 8-1, 8-2communication and coordinationwith ATC, 8-1

operations, 8-1Operations, 8-1equipment failures, 8-5failure annunciators, 8-3

mode annunciators, 8-1non--normal operations, 8-2normal operations, 8-1

P

Pilot reactions to TAWS alerts, 9-8Pilot responsibilities, 6-1prioritization of actions, 6-3resolution advisories, 6-2traffic advisories, 6-1

Premature descent alert, F--8

R

Reactive windshear, 12-1Reversal resolution advisories, 7-12response to a climb now RA,7-12

response to a descend now RA,7-13

S

Strengthening advisories, 7-10response to an increase climbRA, 7-10

response to an increase descentRA, 7-11

System concepts, 2-1, 2-2

T

TA and RA responses, 7-1, 7-2clear of conflict advisory, 7-17corrective resolution advisories,7-4

resolution advisories, 7-2response to a preventive RA, 7-3reversal resolution advisories,7-12

strengthening advisories, 7-10


8000264--001Rev -- Feb 06/2003

IndexIndex--4


Index (cont)

traffic advisories, 7-1weakening or restrictiveadvisories, 7-14

TAL, constraints, 9-9TAWS constraints, 9-9TAWS controls, 10-1TAWS annunciators, 10-2

TAWS displays, 10-4obstacle caution and warning,10-16

terrain advisory line, 10-10terrain alert and warning, 10-12terrain display, 10-4terrain display color schemes,G--1

terrain display patterns, 10-5terrain elevation, 10-7terrain eleview display, 10-20terrain hazard display, 10-18

TAWS extended self--test, 10-32TAWS self--test, 10-27TAWS Self--test Annunciations,10-31

TAWS system components, 9-2aircraft interfaces to the GCAM,9-3

aircraft personality module, 9-6collision prediction and alerting,9-4aircraft flight path prediction,9-4

terrain environmentdetermination, 9-4

control panel, 9-7GPS receiver, 9-6ground collision avoidancemodule, 9-1, 9-3

obstacle collision prediction andalerting, obstacle environmentdetermination, 9-5

terrain display, 9-7TAWS system description, 9-1TAWS theory and description, 9-8”avoid terrain” warning alert, 9-20”don’t sink” caution, 9-28

”pull up” warning, 9-24”pull up” warning alert, 9-19, 9-20aircraft altitude, 9-13aircraft climb rate model, 9-19airport database, 9-13approaches, 9-22avoid clearance sensor, 9-16avoid terrain warning alert, 9-21bank angle, 9-34caution clearance sensor, 9-16convergence envelope, 9-22decision height callouts, 9-38glideslope caution, 9-32GPWS modes of operation, 9-23

mode 1 -- excessive descentrate, 9-23

mode 2 -- excessive terrainclosure rate, 9-26

mode 3 -- loss of altitude aftertakeoff or go around, 9-28

mode 4 -- unsafe terrainclearance not in landingmode, 9-30

mode 5 -- excessive descentbelow glideslope, 9-32

mode 6 -- excessive bankangle and altitude callouts,9-34

minimum descent altitudecallouts, 9-38

obstacle database, 9-13predictive warnings, 9-10reactive warnings, 9-10reactive windshear system, 9-38resolution of the terrain database,9-12

sink rate caution, 9-24terrain avoid envelope, 9-18terrain caution alert, 9-20terrain caution alerts andwarnings, 9-19

terrain caution envelope, 9-18terrain database, 9-10terrain warning envelope, 9-18warning clearance sensor, 9-16


8000264--001Rev -- Feb 06/2003

IndexIndex--5


Index (cont)

TAWS+ displays, terrain elevation,G--1

TCAS advisories, 2-11resolution advisories, 2-12traffic advisories, 2-12

TCAS system descriptiongeneral cautions, 2-5general information, 2-1other transponder systems, 2-4system capabilities, 2-2system theory, 2-8TCAS advisories, 2-11TCAS design and integration, 2-3TCAS II, 2-3TCAS system components, 2-6

Terrain advisory line display, 10-10Terrain alerts display, F--9Terrain database, 9-10Terrain hazard display, F--7Terrain information display, 10-4Traffic advisories, 7-1response to a traffic advisory, 7-1

Traffic display symbols, 3-14data tags, 3-15no bearing advisories, 3-16off scale traffic advisories, 3-16open or hollow blue diamond,3-15

solid amber circle, 3-14solid blue diamond, 3-14solid red square, 3-14

V

Visual alerts, 11-4

W

Warnings, 9-10”pull--up”, 9-20, 9-24, 9-26avoid sensor, 9-14avoid terrain, 9-21clearance sensor, 9-14envelope boundaries, 9-15excessive descent rate, 9-23excessive terrain closure rate,9-26

pilot reactions, 9-8predictive, 9-10reactive, 9-10terrain envelope, 9-18

Weakening or restrictive advisories,7-14adjust climb or descent rate RA,7-14

corrective altitude crossing,maintain rate RA, 7-16

corrective non--crossing, maintainrate RA, 7-15

Windshear visual annunciators,11-5


8000264--001Rev 3 Jun 15/2007

IndexIndex--6



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