Garmin GTX 345R, GTX 33, GTX 330, GTX 335, GTX 345 User manual

GTX 33X and GTX 3X5 ADS-B

Maintenance Manual

Contains Instructions for Continued Airworthiness for

STC SA01714WI

Aircraft make, model, registration number, and serial

number and accompanying STC configuration

information in Appendix A must be completed and saved

with aircraft permanent records.

190-00734-11 September 2019 Revision 7

© 2013-2019 Garmin International or its subsidiaries

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190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page i

Revision

5 10/05/16

6 12/08/17

Revision

Date

RECORD OF REVISIONS

Description

Updated the standard rack part number.
Moved GPS keep alive input requirement to optional interface.
Updated main and ADS-B software to v2.05

Updated GTX 33/330 software to v8.04
Updated GTX 3X5 main software to v2.12 and ADSB software to v2.10
Added models to bonding table B-1

7

09/09/19

Added Diversity unit part numbers and descriptions.

CURRENT REVISION DESCRIPTION

Section Description

1.6.1 Updated to add Diversity units to section.

2 Added Diversity units to list of GTX 3X5 models.

Updated to add Diversity units to section.

2.3

2.4

2.5

2.6 Added GTX 335D and GTX 345D to Table 2-1 GTX Electrical Load.

3 Updated to add Diversity units to section.

3.2 Updated to add Diversity units to section.

3.3 Updated to add Diversity units to section.

Updated Figure 2-3 to include GTX 335D and GTX 335DR units.

Updated to add Diversity units to section.

Updated Figure 2-4 to include GTX 345D and GTX 345DR units.

Updated to add Diversity units to section.

Updated Figure 2-5 to include GTX 335DR and GTX 345DR units.

3.4 Updated to add Diversity units to section.

4.5 Updated to add Diversity units to section.

4.6 Updated to add Diversity units to section.

5.4.2 Added GTX 345D and GTX 345DR to include the J3252 connector.

Added “ADS-B OUT FUNCTION FAIL”, “STANDBY ALERT”, “TRANSPONDER
ACTIVE”, and “DIVERSITY FAIL” pins to Table 5-9 GTX 3X5/3X5R Discrete Outputs.

Changed “AUDIO INHIBIT #1” pin to “AUDIO MUTE” in Table 5-11 GTX 3X5/3X5R
Discrete Inputs.

5.4.4
Changed “AUDIO INHIBIT #2” pin to “AUDIO CANCEL” in Table 5-11 GTX 3X5/3X5R

Discrete Inputs.

Added “TRAFFIC AUDIO MUTE” and “TRAFFIC AUDIO CANCEL” pins in Table 5-11
GTX 3X5/3X5R Discrete Inputs.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page ii

Section Description

Added Table 6-4 and Figure 6-9 GTX 3X5D with Backplate Assembly (P/N 011-04340-

6.3

6.3.1 Updated to add Diversity units to section.

6.3.2 Updated to add Diversity units to section.

6.3.3 Updated to add Diversity units to section.

8.4.1 Updated to add Diversity units to section.

8.4.2 Updated to add Diversity units to section.

8.5.2 Updated to add Diversity units to section.

8.6 Corrected “Part 23” to “Part 43”.

8.8 Updated to add Diversity units to section.

02).

Added Table 6-5 and Figure 6-10 GTX 3X5DR with Backplate Assembly (P/N 011­04340-10).

Appendix A

Updated to add Diversity units to section. Added Diversity sections to Post-Installation
Configuration Log.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page iii

INFORMATION SUBJECT TO EXPORT CONTROL LAWS

WARNING

WARNING

CAUTION

WARNING

CAUTION

NOTE

This document may contain information that is subject to the Export Administration Regulations (EAR)
issued by the United States Department of Commerce (15 CFR, Chapter VII, Subchapter C) and may not
be exported, released, or disclosed to foreign nationals inside or outside of the United States without first
obtaining an export license. A violation of the EAR may be subject to a penalty of up to 10 years
imprisonment and a fine of up to $1,000,000 under Section 2410 of the Export Administration Act of 1979.
Include this notice with any reproduced portion of this document.

This information in this document is subject to change without notice. Visit Garmin’s Dealer Resource

Center for current updates and supplemental information concerning the operation of Garmin products.

DEFINITIONS OF WARNINGS, CAUTIONS, AND NOTES

Warnings indicate that immediate attention must be given to avoid potential

equipment damage and personal injury should the instructions be disregarded.

Cautions indicate an alert to potential damage to the equipment if the

procedural step is not directly followed.

Notes indicate additional information is needed.

This product, its packaging, and its components contain chemicals known to the State of
California to cause cancer, birth defects, or reproductive harm. This notice is being
provided in accordance with California's Proposition 65. If you have any questions or
would like additional information, please refer to our website at

www.garmin.com/prop65.

Perchlorate Material - special handling may apply. Refer to

www.dtsc.ca.gov./hazardouswaste/perchlorate.

The GTX 330/330D and GTX 335/345 units have a special anti-reflective coated display
that is sensitive to waxes and abrasive cleaners. CLEANERS CONTAINING AMMONIA
WILL HARM THE ANTI-REFLECTIVE COATING. It is important to clean the display
using a clean, lint-free cloth, with a cleaner that is safe for anti-reflective coatings.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page iv

TABLE OF CONTENTS

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

1.1 Content, Scope, Purpose.............................................................................................................1-2

1.2 Organization ...............................................................................................................................1-2

1.3 Applicability...............................................................................................................................1-3

1.4 Publications ................................................................................................................................1-3

1.5 Revision and Distribution...........................................................................................................1-3

1.6 Reference....................................................................................................................................1-4

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

2.1 GTX 330/330D...........................................................................................................................2-2

2.2 GTX 33/33D...............................................................................................................................2-4

2.3 GTX 335/335D/335R/335DR ....................................................................................................2-6

2.4 GTX 345/345D/345R/345DR ....................................................................................................2-8

2.5 GTX 335R/335DR/345R/345DR with Legacy G1000 ............................................................2-10

2.6 Electrical Load Information .....................................................................................................2-11

3 GTX CONTROL AND OPERATION.............................................................................................3-1

3.1 GTX 330/330D...........................................................................................................................3-2

3.2 GTX 335/335D/345/345D..........................................................................................................3-4

3.3 GTX 33/33D and GTX 335R/335DR/345R/345DR..................................................................3-7

3.4 GTX 335R/335DR/345R/345DR with Legacy G1000 ..............................................................3-8

3.5 GTX 3X5 Install Tool ..............................................................................................................3-10

4 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS.........................................................4-1

4.1 Applicability...............................................................................................................................4-2

4.2 Airworthiness Limitations..........................................................................................................4-2

4.3 Servicing Information ................................................................................................................4-3

4.4 Maintenance Intervals ................................................................................................................4-4

4.5 Visual Inspection........................................................................................................................4-5

4.6 Electrical Bonding Test..............................................................................................................4-7

4.7 Additional Instructions...............................................................................................................4-7

5 TROUBLESHOOTING ....................................................................................................................5-1

5.1 GTX General Troubleshooting...................................................................................................5-2

5.2 GTX Failure Annunciations .......................................................................................................5-4

5.3 GTX 33X Connector Pinout Information.................................................................................5-11

5.4 GTX 3X5 Connector Pinout Information.................................................................................5-15

6 UNIT REMOVAL AND RE-INSTALLATION..............................................................................6-1

6.1 GTX 330/330D...........................................................................................................................6-2

6.2 GTX 33/33D...............................................................................................................................6-4

6.3 GTX 3X5....................................................................................................................................6-5

6.4 Transponder Antenna ...............................................................................................................6-19

7 SOFTWARE.......................................................................................................................................7-1

7.1 Software Check ..........................................................................................................................7-2

7.2 GTX 33/330 Software Update....................................................................................................7-5

7.3 GTX 3X5 Software Update........................................................................................................7-7

8 SYSTEM CONFIGURATION AND CHECKOUT .......................................................................8-1

8.1 Overview ....................................................................................................................................8-2

8.2 System Checkout........................................................................................................................8-2

8.3 GTX 33/330 Configuration ........................................................................................................8-3

8.4 GTX 3X5 Configuration ............................................................................................................8-4

8.5 GTX Airborne Test Mode ..........................................................................................................8-5

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8.6 Regulatory Test ..........................................................................................................................8-7

8.7 ADS-B Out Test .........................................................................................................................8-8

8.8 GTX 3X5 with TCAS System Test (GX000 Only) ...................................................................8-9

9 SYSTEM RETURN TO SERVICE PROCEDURE........................................................................9-1

9.1 Maintenance Records .................................................................................................................9-1

APPENDIX A INSTALLATION SPECIFIC INFORMATION ........................................................A-1

APPENDIX B SPECIAL BONDING PROCEDURES.......................................................................B-1

B.1 Considerations for Untreated or Bare Dissimilar Metals ..........................................................B-2

B.2 Preparation of Aluminum Surfaces ........................................................................................... B-5

B.3 Composite Aircraft.................................................................................................................... B-6

B.4 Tube-and-Fabric Aircraft ........................................................................................................ B-10

B.5 Bonding Jumper ...................................................................................................................... B-12

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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LIST OF FIGURES

Figure 2-1 GTX 330 or GTX 330D Interface Summary ........................................................................2-3

Figure 2-2 GTX 33 or GTX 33D Interface Summary ............................................................................2-5

Figure 2-3 GTX 335/335D/335R/335DR Interface Summary ...............................................................2-7

Figure 2-4 GTX 345/345D/345R/345DR Interface Summary ...............................................................2-9

Figure 2-5 GTX 335R/335DR/345R/345DR Interface Summary with Legacy G1000 .......................2-10

Figure 3-1 GTX 330/330D Front Panel ..................................................................................................3-2

Figure 3-2 GTX 335/335D/345/345D Front Panel ................................................................................3-4

Figure 3-3 GTN 7XX Transponder Control ...........................................................................................3-7

Figure 3-4 GTN 6XX Transponder Control ...........................................................................................3-7

Figure 3-5 GNS 480 Transponder Control .............................................................................................3-7

Figure 3-6 G1000 Transponder Control .................................................................................................3-9

Figure 3-7 G1000 Transponder Control .................................................................................................3-9

Figure 3-8 USB A and USB B Connectors ..........................................................................................3-10

Figure 3-9 GTX 3X5 State Page ..........................................................................................................3-11

Figure 3-10 GTX 3X5 Status Page .........................................................................................................3-12

Figure 3-11 GTX 3X5 Configuration Group ..........................................................................................3-13

Figure 3-12 GTX 3X5 Diagnostics Group .............................................................................................3-14

Figure 3-13 GTX 3X5 Product Data Group ...........................................................................................3-15

Figure 5-1 GTX (All Models) Transponder Troubleshooting ................................................................5-3

Figure 5-2 GTX 330/330D Transponder Failure/Fault Messages ..........................................................5-4

Figure 5-3 GTX 33/33D Transponder Failure/Fault Messages ..............................................................5-5

Figure 5-4 GTX 3X5 Transponder Alerts ..............................................................................................5-6

Figure 5-5 Rear View, Connector P3301 .............................................................................................5-11

Figure 5-6 GTX 33/330 ARINC 429 Connections ...............................................................................5-14

Figure 5-7 Rear View, Connector J3251 ..............................................................................................5-15

Figure 5-8 Rear View, Connector J3252 ..............................................................................................5-17

Figure 6-1 GTX 330 Mounting Rack/Connector Assembly ..................................................................6-3

Figure 6-2 GTX 33 Mounting Rack/Connector Assembly ....................................................................6-4

Figure 6-3 GTX 3X5 Connector Kits .....................................................................................................6-5

Figure 6-4 GTX 3X5 without GPS Back Plate Assembly (P/N 011-02976-00) ....................................6-6

Figure 6-5 GTX 3X5 with GPS Back Plate Assembly (P/N 011-02976-01) .........................................6-6

Figure 6-6 GTX 3X5 Vertical Mount without GPS, Back Plate Assem

Figure 6-7 GTX 3X5 Vertical Mount with GPS, Back Plate Assembly (P/N 011-02976-11) ..............6-8

Figure 6-8 GTX 3X5 Vertical Mount with TNC XPDR Back Plate Assembly (P/N 011-02976-12) ...6-8

Figure 6-9 GTX 3X5D with Backplate Assembly (P/N 011-04340-02) ................................................6-9

Figure 6-10 GTX 3X5DR with Backplate Assembly (P/N 011-04340-10) ...........................................6-10

Figure 6-11 GTX 3X5 Mounting Rack/Connector Assembly ...............................................................6-12

Figure 6-12 GTX 3X5R Standard Mounting Rack/Connector Assembly ..............................................6-14

Figure 6-13 GTX 3X5R G1000 Mounting Rack/Connector Assembly .................................................6-14

Figure 6-14 GTX 3X5R Vertical Mounting Rack/Connector Assembly ...............................................6-16

Figure 6-15 Garmin Altitude Encoder with Back Plate Assembly ........................................................6-18

Figure 7-1 GTX 330 Start-Up Screen ....................................................................................................7-2

Figure 7-2 GTX 330 Product Data Page ................................................................................................7-2

Figure 7-3 GTX 3X5 Start-Up Screen ....................................................................................................7-3

Figure 7-4 GTX 3X5 Product Data Page ...............................................................................................7-3

Figure 7-5 GTN 6XX/7XX System Page ...............................................................................................7-3

Figure 7-6 GX000 System Status Page ..................................................................................................7-4

Figure 7-7 Software Update Connection ................................................................................................7-5

bly (P/N 011-02976-10) .........6-7

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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Figure 7-8 GTX 3X5 Install Tool Software Upload Page ......................................................................7-8

Figure B-1 Electrical Bonding Preparation – Nut Plate .........................................................................B-2

Figure B-2 Electrical Bonding Preparation – Bolt/Nut Joint .................................................................B-2

Figure B-3 Electrical Bond Preparation – Terminal Lug .......................................................................B-2

Figure B-4 Fiberglass Insulation for Carbon Material ...........................................................................B-6

Figure B-5 Aluminum Tape Joint ..........................................................................................................B-7

Figure B-6 Aluminum Tape Ground Termination ................................................................................. B-8

Figure B-7 Remote GTX Aluminum Tape Installation ......................................................................... B-9

Figure B-8 Electrical Bonding Using Conductive Clamp .................................................................... B-11

Figure B-9 Bonding Strap .................................................................................................................... B-13

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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LIST OF TABLES

Table 1-1 Reference Documentation ....................................................................................................1-3

Table 2-1 GTX Electrical Load ...........................................................................................................2-11

Table 4-1 Maintenance Intervals ...........................................................................................................4-4

Table 5-1 GTX 33X Pinout .................................................................................................................5-11

Table 5-2 GTX 33X Encoded Altitude Pin Assignments ...................................................................5-13

Table 5-3 GTX 33/330 Discrete Outputs ............................................................................................5-13

Table 5-4 GTX 33/330 Discrete Inputs ...............................................................................................5-14

Table 5-5 GTX 33/330 RS-232 Connections ......................................................................................5-14

Table 5-6 J3251 Pinout .......................................................................................................................5-15

Table 5-7 J3252 Pinout .......................................................................................................................5-17

Table 5-8 GTX 3X5/3X5R Encoded Altitude Pin Assignments ........................................................5-18

Table 5-9 GTX 3X5/3X5R Discrete Outputs ......................................................................................5-19

Table 5-10 GTX 3X5/3X5R Configurable Output Pins .......................................................................5-19

Table 5-11 GTX 3X5/3X5R Discrete Inputs ........................................................................................5-20

Table 5-12 GTX 3X5/3X5R Configurable Input Pins ..........................................................................5-20

Table 5-13 GTX 3X5/3X5R RS-232 Connections ...............................................................................5-21

Table 5-14 GTX 3X5/3X5R ARINC 429 Connections ........................................................................5-21

Table 5-15 GTX 345/345R RS-422 Connections .................................................................................5-21

Table 5-16 GTX 345/345R HSDB Connections ...................................................................................5-22

Table 6-1 GTX 3X5 Connector Kit Hardware ......................................................................................6-5

Table 6-2 Standard/G1000 Mount Back Plate Hardware .....................................................................6-5

Table 6-3 Vertical Mount Back Plate Hardware ...................................................................................6-7

Table 6-4 Standard and G1000 Mount Backplate Hardware ................................................................6-9

Table 6-5 Vertical Mount Backplate Hardware ..................................................................................6-10

Table 6-6 Garmin Altitude Encoder Kit - P/N 011-03080-00 ............................................................6-18

Table 8-1 Ramp Test Pressure Altitude Check Scenario ......................................................................8-9

Table B-1 Ground Plane Definitions and Ground Path Resistance Requirements ...............................B-3

Table B-2 Composite Airframe Bonding Hardware .............................................................................B-7

Table B-3 Tube and Fabric Airframe Bonding Hardware ..................................................................B-10

Table B-4 Airframe Bonding Hardware .............................................................................................B-13

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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1 INTRODUCTION

1.1 Content, Scope, Purpose ...................................................................................................................1-2

1.2 Organization......................................................................................................................................1-2

1.3 Applicability .....................................................................................................................................1-3

1.4 Publications.......................................................................................................................................1-3

1.5 Revision and Distribution .................................................................................................................1-3

1.6 Reference ..........................................................................................................................................1-4

1.6.1 Terminology ...............................................................................................................................1-4

1.6.2 Acronyms ...................................................................................................................................1-4

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 1-1

1.1 Content, Scope, Purpose

This document provides Instructions for Continued Airworthiness (ICA) of the GTX 33X and GTX 3X5
with ADS-B functionality installed and compliant to ADS-B Out version 2, under AML STC SA01714WI.
This document satisfies the requirements for continued airworthiness as defined by 14 CFR Part 23.1529
and Appendix G. Information in this document is required to maintain the continued airworthiness of the
GTX 33X and GTX 3X5.

1.2 Organization

The following outline briefly describes the organization of this manual.

Section 2: System Overview

Provides a description of the GTX 33X and GTX 3X5 equipment installed by this STC.

Section 3: Control and Operation

Provides basic control and operation information specifically tailored to maintenance practices.

Section 4: Instructions for Continued Airworthiness

Provides instructions for continued airworthiness of the GTX 33X and GTX 3X5 ADS-B units.

Section 5: Troubleshooting

Provides troubleshooting information to aid in diagnosing and resolving problems with GTX 33X and
GTX 3X5 system equipment.

Section 6: Unit Removal and Reinstallation

Provides instructions for the removal and replacement of GTX 33X and GTX 3X5 ADS-B units.

Section 7: Software

Provides instructions for loading software on GTX 33X and GTX 3X5 ADS-B units.

Section 8: System Configuration and Checkout

Provides instructions for configuring and testing of GTX 33X and GTX 3X5 system equipment.

Section 9: System Return to Service Procedure

Specifies return-to-service procedures to be performed upon completion of maintenance to GTX 33X and
GTX 3X5 system equipment.

Appendix A: Aircraft Specific Information

Provides a template to record aircraft specific installation and configuration data for GTX 33X and
GTX 3X5 system equipment.

Appendix B: Special Bonding Procedures

Provides instructions for achieving an electrical bond with GTX 33X and GTX 3X5 system equipment.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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1.3 Applicability

This document applies to all aircraft with either the GTX 33X or the GTX 3X5 installed in accordance with
STC SA01714WI. Modification of an aircraft by this Supplemental Type Certificate (STC) obligates the
aircraft operator to include the maintenance information provided by this document in the operator’s
Aircraft Maintenance Manual and the operator’s Aircraft Scheduled Maintenance Program.

1.4 Publications

In addition to this manual, the following documents are recommended to perform maintenance based on
the installed and interfaced equipment. It is the responsibility of the owner/operator to ensure the latest
applicable versions of these documents are used during operation, servicing, or maintenance of the
airplane.

Table 1-1 Reference Documentation

Document Garmin P/N

GTX 33X and GTX 3X5 ADS-B AML STC Equipment List
GTN 625/635/650 Pilot’s Guide
AFMS, GTX 33X and GTX 3X5 AML STC
GTN 725/750 Pilot’s Guide
GNS 400W Series Installation Manual
GNS 500W Series Installation Manual
GNS 480 (CNX80) Color GPS/NAV/COM Installation Manual
GNS 480 Pilot’s Guide
G1000 System Installation Manual
GTN 6XX/7XX Part 23 AML STC Installation Manual
GTX 3XX Part 23 AML STC Installation Manual

005-00734-05

190-01004-03

190-00734-15

190-01007-03

190-00356-08

190-00357-08

560-0982-01

190-00502-00

190-00303-00

190-01007-A3

190-00734-10

1.5 Revision and Distribution

This document is required for maintaining the continued airworthiness of the aircraft. Garmin Dealers may
obtain the latest revision of this document at the Garmin Dealer Resource Center

Dealers are notified of manual revision changes via a Garmin Service Bulletin.

Owner and operators may obtain the latest revision of this document at www.flyGarmin.com
contacting a Garmin dealer. Garmin contact information is available at www.flyGarmin.com

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 1-3

, website.

or by

.

1.6 Reference

1.6.1 Terminology

Except where specifically noted, references made to “GTX 33X” or “GTX 3X5” will apply to the
GTX 330/330D/33/33D or GTX 335/335D/335R/335DR/345/345D/345R/345DR, respectively.

ADS-B or ADS-B Out refers to version 2 ADS-B Out only.

ADS-B In refers to TIS-B traffic and FIS-B weather received from ground stations over UAT as well as
ADS-B and ADS-R traffic targets received directly over 1090 MHz or UAT.

Throughout this document references will be made to metallic aircraft. For the purposes of this manual,
metallic aircraft will be those with an aluminum skin. Nonmetallic aircraft refers to all other aircraft
(e.g., wooden aircraft, aircraft with composite skin, or aircraft with tube and fabric construction).

Unless otherwise stated, all units of measure are US standard units.

The term squitter refers to a burst or broadcast of aircraft-tracking data that is transmitted periodically by a
Mode S transponder without interrogation from a controller’s radar.

1.6.2 Acronyms

AC: Advisory Circular ICA: Instructions for Continued Airworthiness

ADC: Air Data Computer ICAO: International Civil Aviation Organization

ADS-B: Automatic Dependent Surveillance -

Broadcast

AHRS: Attitude Heading Reference System MFD: Multifunction Display

AML: Approved Model List PED: Portable Electronic Device

ATC: Air Traffic Control SBAS: Satellite-Based Augmentation System

ATCRBS: Air Traffic Control Radar Beacon System SPI: Special Position Identifier

EGNOS: European Geostationary Navigation

Overlay Service

ES: Extended Squitter STC: Supplemental Type Certificate

FAA: Federal Aviation Administration TAS: Traffic Advisory System

FIS-B: Flight Information System-Broadcast TCAS: Traffic Alert and Collision Avoidance

GAE: Garmin Altitude Encoder TIS: Traffic Information Service

GNS: Garmin Navigation System TSO: Technical Standard Order

GNSS: Global Navigation Satellite System UAT: Universal Access Transceiver

GPS: Global Positioning System VSWR: Voltage Standing Wave Ratio

GTN: Garmin Touchscreen Navigator

GTX: Garmin Transponder

I/O: Input/Output

SRM: Structural Repair Manual

System

WAAS: Wide Area Augmentation System

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2 SYSTEM DESCRIPTION

2.1 GTX 330/330D .................................................................................................................................2-2

2.2 GTX 33/33D .....................................................................................................................................2-4

2.3 GTX 335/335D/335R/335DR...........................................................................................................2-6

2.4 GTX 345/345D/345R/345DR...........................................................................................................2-8

2.5 GTX 335R/335DR/345R/345DR with Legacy G1000...................................................................2-10

2.6 Electrical Load Information............................................................................................................2-11

Garmin GTX 33X and GTX 3X5 units operate on radar frequencies, receiving ground radar or TCAS
interrogations. The GTX transmits a coded response of pulses to ground-based radar on a frequency of
1090 MHz. Each unit has IDENT capability and replies to ATCRBS Mode A, Mode C and Mode S
All-Call interrogation. The GTX 345/345D/345R/345DR units include ADS-B In which provides TIS-B
and FIS-B data via UAT and 1090 MHz. The GTX 3X5 units offer an optional Garmin altitude encoder to
meet the required barometric pressure altitude source and an optional internal GPS/SBAS source to meet
the required GNSS position source integrity for ADS-B Out.

The Garmin transponders approved by this STC are in the family of GTX 33X and GTX 3X5 transponders.

The ES option of the GTX 33X units provides ADS-B extended squitter functionality.
The GTX 33X models include:

 GTX 33
 GTX 330
 GTX 33D
 GTX 330D

The GTX 3X5 units all provide ADS-B Out functionality. GTX 345/345R units provide ADS-B In. The
GTX 3X5 models include:

 GTX 335
 GTX 335D
 GTX 345
 GTX 345D
 GTX 335R
 GTX 335DR
 GTX 345R
 GTX 345DR

ADS-B technology improves situational awareness and flight safety. A Garmin transponder with ADS-B
capabilities will automatically transmit position, velocity, and heading information to other aircraft and
ground stations. The current air traffic control system depends on a transponder request for pertinent
aircraft information, whereas ADS-B provides automatic transmission of aircraft information without a
request.

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Rev. 6 Page 2-1

2.1 GTX 330/330D

GTX 330/330D units are stand alone, panel mounted units that operate through the integrated display.
GTX 330/330D units can be controlled by an external control unit such as the GTN 6XX/7XX or the
GNS 480. They can display TIS-A information on an approved display unit, via an RS-232 digital
interface.

GTX 330/330D units provide the following features.

 Mode S transponder
 ADS-B Out capability
 Entry and display of squawk code and flight ID
 Display of pressure altitude
 Display of density altitude
 Display of outside air temp
 Display of flight timers
 Audio output
 TIS-A traffic output to a compatible display

The transponder annunciates when the unit has an ADS-B Out failure to alert the crew that the unit has a
degraded ADS-B system.

GTX 330/330D units communicate through the following interfaces.

 ARINC 429
 RS-232
 Gray code
 Discrete I/O

Power is provided by the aircraft’s existing avionics bus. Non-diversity GTX 330 units interface with a
transponder antenna mounted to the bottom of the fuselage. GTX 330D diversity units interface to a
transponder antenna mounted to the top of the fuselage as well as the antenna mounted to the bottom.

Figure 2-1 provides a summary of the interfaces provided for the GTX 330 or GTX 330D. Refer to
GTX 3XX Part 23 AML STC Installation Manual for interfaces allowed under this STC.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-2

Figure 2-1 GTX 330 or GTX 330D Interface Summary

GTX 330

or

GTX 330D

Bottom Antenna

GTX 330D

Installs Only

Traffic System

Audio Panel

Optional Interfaces

Heading Source

Secondary GPS

Display

Required Interfaces

Altitude Source

Power/Ground

Top Antenna

GPS

Temperature

Squat Switch

External STBY

External Ident

Radar Altitude

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-3

2.2 GTX 33/33D

GTX 33/33D units are remote mounted and require a display/control interface as provided by the
GTN 6XX/7XX or GNS 480 in order to be installed in accordance with this STC. Basic transponder
functions of the GTX 33/33D are identical to the GTX 330/330D.

GTX 33/33D units provide the following features.

 Mode S transponder
 ADS-B Out capability
 Entry and display of squawk code and flight ID*
 Display of pressure altitude*
 Display of density altitude*
 Display of outside air temp*
 Display of flight timers*
 Audio output
 TIS-A traffic output to a compatible display

*Requires supported external control and display system

The transponder annunciates when the unit has an ADS-B Out failure to alert the crew that the unit has a
degraded ADS-B system.

GTX 33/33D units communicate through the following interfaces.

 ARINC 429
 RS-232
 Gray code
 Discrete I/O

Power is provided by the aircraft’s existing avionics bus. Non-diversity GTX 33 units interface with a
transponder antenna mounted to the bottom of the fuselage. GTX 33D units interface to a transponder
antenna mounted to the top of the fuselage as well as an antenna mounted to the bottom.

Figure 2-2 provides a summary of the interfaces provided for the GTX 33 or GTX 33D. Refer to
GTX 3XX Part 23 AML STC Installation Manual for interfaces allowed under this STC.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-4

Figure 2-2 GTX 33 or GTX 33D Interface Summary

GTX 33

or

GTX 33D

Bottom Antenna

GTX 33D

Installs Only

Garmin

GTN 6XX/7XX

Or

GNS 480

Traffic System

Audio Panel

Optional Interfaces

Heading Source

Secondary GPS

Temperature

Squat Switch

Required Interfaces

Altitude Source

Power/Ground

Top Antenna

External Ident

External Standby

Radar Altitude

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-5

2.3 GTX 335/335D/335R/335DR

The GTX 335/335D/335R/335DR units are panel or remote mounted units providing Mode S with ADS-B
Out extended squitter capability. The panel mounted unit contains an integrated display while the remote
mounted unit requires an interface to a control source for normal operation and functionality.

GTX 335/335D/335R/335DR units provide the following features:

 Mode S transponder
 ADS-B Out capability
 Optional internal GNSS receiver
 Optional altitude encoder module
 Entry and display of squawk code and flight ID
 Display of pressure altitude
 Display of outside air temp
 Display of density altitude
 Display of flight timers
 Audio output
 TIS-A traffic output to a compatible display

The transponder annunciates when the unit has an ADS-B Out failure to alert the crew that the unit has a
degraded ADS-B system. GTX 335/335R units interface with a transponder antenna mounted to the
bottom of the fuselage. GTX 335D/335DR units interface to a transponder antenna mounted to the top of
the fuselage as well as an antenna mounted to the bottom.

GTX 335/335D/335R/335DR units communicate through the following interfaces:

 ARINC 429
 RS-232
 Gray code
 Discrete I/O

Figure 2-3 provides a summary of the interfaces provided for the GTX 335/335D/335R/335DR. Refer to
GTX 3XX Part 23 AML STC Installation Manual for interfaces allowed under this STC.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-6

GTX 335/335R/

335D/335DR

GPS Antenna

GPS Source

Audio Panel

GTX 3X5 with GPS only

GTX 335R/335DR

Control

Power/Ground

Altitude Source

Heading Source

Air Data Source

Secondary GPS

Radio Altitude

Source

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Squat Sw itch

Garmin Altitude

Encoder

OR

Temperature

External Ident

External Standby

Traffic System

For XPDR Cross-Talk

Keep Alive Input

Bottom Antenna

GTX 335D/335DR

Installs O nly

Top Antenna

Figure 2-3 GTX 335/335D/335R/335DR Interface Summary

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-7

2.4 GTX 345/345D/345R/345DR

The GTX 345/345D/345R/345DR units are panel or remote mounted units providing Mode S with ADS-B
Out extended squitter, and UAT and 1090 receivers for ADS-B In capabilities. The panel mounted unit
contains an integrated display while the remote mounted units require an interface to a control source for
normal operation and functionality.

GTX 345/345D/345R/345DR units provide the following features:

 Mode S transponder
 ADS-B Out capability
 ADS-B In capability with built-in 1090 MHz and UAT receivers
 Optional internal GNSS receiver
 Optional altitude encoder module
 Entry and display of squawk code and flight ID
 Display of pressure altitude
 Display of outside air temp
 Display of density altitude
 Display of flight timers
 Audio output
 Bluetooth interface for display of weather and traffic on portable devices

The transponder annunciates when the unit has an ADS-B failure to alert the crew that the unit has a
degraded ADS-B In or ADS-B Out system. GTX 345/345R units interface with a transponder antenna
mounted to the bottom of the fuselage. GTX 345D/345DR units interface to a transponder antenna
mounted to the top of the fuselage as well as an antenna mounted to the bottom.

GTX 345/345D/345R/345DR units communicate through the following interfaces:

 HSDB
 ARINC 429
 RS-232
 RS-422
 Gray code
 Discrete I/O

Figure 2-4 provides a summary of the interfaces provided for the GTX 345/345D/345R/345DR. Refer to
GTX 3XX Part 23 AML STC Installation Manual for interfaces allowed under this STC.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-8

TAS/TCAS I

Traffic Sensor

ADS-B Traffic
FIS-B Display

Bluetooth Device

GTX 345/345R/

345D/345DR

GPS Antenna

GPS Source

Audio Panel

Bottom Antenna

GTX 3X5 with GPS only

GTX 345R/345DR

Control

Power/Ground

Altitude Source

Heading Source

Air D ata S ource

Secondary GPS

Radio Altitude

Source

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Squat Switch

Bluetooth

External Traffic

Annunciator

For N o Display Install

Garmin Altitude

Encoder

OR

Temperature

External Ident

External Standby

Keep Alive Input

Bottom Antenna

GTX 345D/345DR

Installs O nly

Top Antenna

Time Mark

GTX 345D/345DR

only

Figure 2-4 GTX 345/345D/345R/345DR Interface Summary

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-9

2.5 GTX 335R/335DR/345R/345DR with Legacy G1000

Bluetooth Device

GTX 335R/335DR/

345R/345DR

GPS Antenna

Audio Panel

GTX 3X5 with GPS only

Power/Ground

GIA #1

Existing LRU

New LRU

Legend

Optional Interfaces

Required Interfaces

Bluetooth

RS-232

RS-232

GIA #2

RS-232

RS-422

TRAFFIC

WEATHER

ARINC 429

TRUE HEADING

GIA #2

GIA 63W

GPS Source

GIA 63W software dependent,

refer to IM for compatible software

TAS/TCAS

AURAL MUTE

DISCRETE

ARINC 429

DISCRETE

ARINC 429

TRAFFIC

XPDR / HEADING

DISCRETE

STBY/OPR

SELF TEST

Landing Gear

Switch

DISCRETE

Keep Alive Input

Bottom Antenna

GTX 335DR/345DR

Installs Only

Top Antenna

Time Mark

GTX 345DR only

The Legacy G1000 configuration includes certain G1000 systems that can be updated with a G1000
interface card. The GTX 335R/335DR provides all the functions listed under the GTX 335/335D/335R/
335DR to include ADS-B Out. The GTX 345R provides all the functions listed under the GTX 345/345D/
345R/345DR with the exception that the ADS-B In traffic and weather will be displayed as an emulation of
the GDL 90 weather and traffic displays. The GTX 345R/345DR provides FIS-B weather (NEXRAD and
METARS) and TIS-B traffic within the confines of the GDL 90 interface. The GTX 345R/345DR provides
TIS-B traffic and FIS-B weather on PED via Bluetooth. Refer to GTX 3XX Part 23 AML STC Installation
Manual for additional information.

Figure 2-5 provides a basic summary of the GTX 335R/335DR/345R/345DR interface for the legacy
G1000 system.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-10

Figure 2-5 GTX 335R/335DR/345R/345DR Interface Summary with Legacy G1000

2.6 Electrical Load Information

Electrical load information for the GTX is provided below. Appendix A of this document contains details
specific to the load changes for the installation.

Table 2-1 GTX Electrical Load

Unit Characteristic

Maximum full TSO reply rate 3.1 A 1.6 A

GTX 33/330

Maximum quiescent 1.1 A 0.85 A

Input current, typical 0.57 A 0.29 A

GTX 335/335D

Input current, maximum 0.86 A 0.43 A

Specification

14 VDC 28 VDC

GTX 335, GPS

Input current, typical 0.72 A 0.36A

Input current, maximum 1.22 A 0.61 A

Input current, typical 0.72 A 0.36 A

GTX 345/345D

Input current, maximum 1.30 A 0.65 A

Input current, typical 1.07 A 0.54 A

GTX 345, GPS

Input current, maximum 1.43 A 0.72 A

GTX 335/345, GPS Input current, GPS KEEP ALIVE

65 µA typical 20 µA typical

85 µA maximum 40 µA maximum

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 6 Page 2-11

3 GTX CONTROL AND OPERATION

NOTE

3.1 GTX 330/330D .................................................................................................................................3-2

3.2 GTX 335/335D/345/345D ................................................................................................................3-4

3.3 GTX 33/33D and GTX 335R/335DR/345R/345DR ........................................................................3-7

3.4 GTX 335R/335DR/345R/345DR with Legacy G1000.....................................................................3-8

3.5 GTX 3X5 Install Tool.....................................................................................................................3-10

3.5.1 State Page .................................................................................................................................3-11

3.5.2 Status Page ...............................................................................................................................3-12

3.5.3 Configuration Group ................................................................................................................3-13

3.5.4 Diagnostics Group ....................................................................................................................3-14

3.5.5 Product Data Group..................................................................................................................3-15

3.5.6 Software Upload.......................................................................................................................3-15

Control and operation of GTX 330/330D and GTX 335/335D/345/345D units occur through the front
panel of the GTX. Control and operation of the remote mounted GTX 33/33D and GTX 335R/335DR/
345R/345DR is handled through the external interface provided via the GTN 6XX/7XX or GNS 480.
ADS-B In information from the GTX 345 can be displayed through the external interface provided via the
GTN 6XX/7XX or GNS 400W/500W Series. Figure 3-3 and Figure 3-4 show display units control of the
transponder. Figure 3-5 shows transponder control using the GNS 480.

In specific installations, the GDU 1XXX (of the G1000 system) provides control and operation of the
remote mounted GTX 335R/335DR/345R/345DR units. Section 3.4 describes the functions of the G1000
system.

The selected identification code should be entered carefully, either one assigned by air
traffic control for IFR flight or an applicable VFR transponder code.

Important Codes

1200 VFR code for any altitude in the US (refer to ICAO standards)

7000 VFR code commonly used in Europe (refer to ICAO standards)

7500 Hijack code (aircraft is subject to unlawful interference)

7600 Loss of communications

7700 Emergency

Avoid selecting code 7500 and all codes in the 7600-7777 range. These codes trigger special emergency
alerts in ATC monitoring facilities. An aircraft’s transponder code is used for ATC tracking purposes,
therefore be careful when making routine code changes.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-1

3.1 GTX 330/330D

NOTE

NOTE

Figure 3-1 GTX 330/330D Front Panel

Function Selection Keys

The function selection keys are:

OFF Powers off the GTX 330.

STBY Selects the standby mode. Pressing the STBY key when the GTX 330 is powered off

automatically powers the unit on in standby mode. When in standby mode, the transponder
does not reply to interrogations. If using software v8.02 or later, GND mode is
automatically determined using either a squat switch or calculated data from various system
inputs including GPS data from an approved control/display unit such as a GTN 6XX/7XX,
GNS 400W/500W Series, or GNS 480.

ON Selects Mode A and Mode S. Pressing the ON key when the GTX 330 is powered off

automatically powers on the unit in Mode A and will transmit a squawk code when
interrogated.The transponder replies to Mode A and Mode S interrogations, as indicated by
the reply symbol (®). The replies do not include altitude information.

If the transponder is in the ON or ALT operating mode, the transponder becomes an active
part of the Air Traffic Control Radar Beacon System (ATCRBS). The transponder
responds to interrogations from TCAS equipped aircraft.

ALT Selects Mode A, Mode C, and Mode S. Pressing the ALT key when the GTX 330 is

powered off automatically powers on the unit in altitude reporting mode.The transponder
replies to identification, altitude and Mode S interrogations as indicated by the reply symbol
(®). Replies to altitude interrogations include the standard pressure altitude received from
an external altitude source, which is not adjusted for barometric pressure.

IDENT Pressing the IDENT key activates the Special Position Identification (SPI) Pulse for 18

seconds, identifying the transponder return from others on an air traffic controller’s screen.
During the IDENT period, the word “IDENT” appears in the upper left corner of the display.

VFR Sets the transponder code to the pre-programmed VFR code selected in Configuration mode

(Set to 1200 at the factory). Pressing the VFR key again restores the previous identification
code.

The VFR key is on (functional) by default, but can be disabled in configuration mode.

FUNC Changes the page shown on the right side of the display. Display data includes pressure

altitude, flight time, altitude monitor, count up, and count down timers. In the
Configuration mode, steps through the function pages.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-2

START/STOP Starts and stops the altitude monitor, count up, count down, and flight timers.

CRSR Initiates entry of the starting time for the count down timer and cancels transponder code

entry. Selects changeable fields in Configuration mode. If using software v8.02 or later,
holding the CRSR key during power on will place the unit into a Ground Test mode that
forces the aircraft into an airborne status for testing purposes.

CLR Resets the count up, count down, and flight timers. Cancels the previous key press during

code selection and count down entry. Used in Configuration mode.

8 Reduces contrast and display brightness when the respective fields are displayed and

enters the number eight into the count down timer. Used in Configuration mode.

9 Increases contrast and display brightness when the respective fields are displayed and

enters the number nine into the count down timer. Used in Configuration mode.

Code Selection

Code selection is entered with eight keys (0 – 7) providing 4,096 active identification codes. Pushing one
of these keys begins the code selection sequence. The new code is not activated until the fourth digit is
entered. Pressing the CLR key moves the cursor back to the previous digit. Pressing the CLR key when
the cursor is on the first digit of the code, or pressing the CRSR key during code entry, removes the cursor
and cancels data entry, restoring the previous code. You may press the CLR key up to five seconds after
code entry is complete to return the cursor to the fourth digit. The numbers 8 and 9 are not used for code
entry, only for entering a count down time, contrast and display brightness, and data selection in the
Configuration mode.

Function Display

PRESSURE ALT Displays the altitude data supplied to the GTX 330 in feet, hundreds of

feet (flight level), or meters, depending on configuration.

FLIGHT TIME Displays the flight time, controlled by the START/STOP key or by one

of four airborne sources (squat switch, GPS ground speed recognition, air
data airspeed recognition, or altitude increase) as configured during
installation. The timer begins when the GTX 330 determines that the
aircraft is airborne.

ALT MONITOR Controlled by START/STOP key. Activates a voice alarm and warning

annunciator when altitude limit is exceeded.

OAT/DALT Displayed when the GTX 330 is configured with temperature input.

Displays outside air temperature and density altitude.

COUNT UP Timer controlled by START/STOP and

COUNT DOWN Timer controlled by START/STOP, CLR, and CRSR keys. The initial

count down time is entered with the 0 – 9 keys.

CONTRAST This page is only displayed if manual contrast mode is selected in

Configuration mode. Contrast is controlled by the 8 and 9 keys.

DISPLAY This page is only displayed if manual backlighting mode is selected in

Configuration mode. Backlighting is controlled by the 8 and 9 keys.

ADS-B TX Controlled by START/STOP key. Starts/stops extended squitter

function.

FLIGHT ID If the GTX 33X is using software v8.02 or later and the system is

configured to allow the pilot to edit the flight ID, then the flight ID may
be entered using the CRSR key. Otherwise the flight ID is set in
configuration mode and cannot be changed during normal operation.

CLR keys.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-3

3.2 GTX 335/335D/345/345D

NOTE

Figure 3-2 GTX 335/335D/345/345D Front Panel

Function Selection Keys

The function selection keys are:

OFF Powers off the GTX 3X5.

STBY Selects the Standby mode. Pressing the STBY key when the GTX 3X5 is powered off

automatically powers the unit on in standby mode. When in Standby mode, the transponder
does not reply to interrogations but new codes can be entered and a SBY indication appears
on the display.

ON Selects the On mode, which generates Mode A and Mode S replies, but Mode C altitude

reporting is inhibited. Pressing the ON key when the GTX 3X5 is powered off automatically
powers on the unit in Mode A and will transmit a squawk code when interrogated. ADS-B
Out will not return barometric altitude as it switches to GPS altitude in this mode.
Interrogations are indicated by the reply symbol (®). The replies do not include altitude
information.

If the transponder is in the ON or ALT operating mode, the transponder becomes an active
part of the Air Traffic Control Radar Beacon System (ATCRBS). The transponder
responds to interrogations from TCAS equipped aircraft.

ALT Altitude mode is automatically selected when the aircraft becomes airborne using the unit’s

air/ground logic or when the ALT key is pressed. Pressing the ALT key when the
GTX 3X5 is powered off automatically powers on the unit in altitude reporting mode. While
the aircraft is on the ground and in ALT mode, the transponder does not allow Mode A and
Mode C replies, but it does permit acquisition squitter and replies to Mode S interrogations.

While the aircraft is in ALT mode and airborne, it will generate Mode A, Mode C and Mode
S replies as well as transmit acquisition and extended squitter, including ADS-B Out.

All transponder interrogations are indicated by the reply symbol (®).

IDENT Pressing the IDENT key activates the Special Position Identification (SPI) Pulse for 18

seconds, identifying the transponder return from others on an air traffic controller’s screen.
During the IDENT period, the word “IDENT” appears in the upper left corner of the display.

VFR Sets the transponder code to the pre-programmed VFR code selected in Configuration mode

(Set to 1200 at the factory). Pressing the VFR key again restores the previous identification
code.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-4

FUNC In normal mode, pressing the FUNC key changes the subpage group shown on the right side

of the display. Subpages include flight ID, pressure altitude, flight time, altitude monitor,
system count up, and count down timers. In the Configuration mode, steps through the
function pages.

ENT Confirms entry for selected item and moves the cursor to the next editable item, or function

selection, in configuration and normal operation. Starts and stops the altitude monitor, count
up, count down, and flight timers.

CRSR Selects changeable fields in configuration and normal operation. Initiates entry of the

starting time for the count down timer and cancels transponder code entry. Holding the
CRSR key during power on will place the unit into a Ground Test mode that forces the
aircraft into an airborne status for testing purposes.

CLR Resets the count up, count down and flight timers. Cancels the previous key press during

code selection, count down entry, or flight ID entry. Used in Configuration mode to scroll
through the function pages.

8 Used as a scroll-up key to navigate through page groups in normal and configuration mode.

9 Used as a scroll-down key to navigate through page groups in normal and configuration

mode.

Code Selection

Code selection is entered with eight keys (0 – 7) providing 4,096 active identification codes. Pushing one
of these keys begins the code selection sequence. The new code is not activated until the fourth digit is
entered. Pressing the CLR key moves the cursor back to the previous digit. Pressing the CLR key when
the cursor is on the first digit of the code, or pressing the CRSR key during code entry, removes the cursor
and cancels data entry, restoring the previous code. The numbers 8 and 9 are not used for code entry, only
for flight ID entry, count down time, aircraft tail number entry, and data selection in Configuration and
Normal mode.

Configuration Mode

To enter configuration mode, press and hold the ENT key, then energize the unit. To exit configuration
mode, press and hold the OFF key until the unit de-energizes.

 To cycle through the pages, press the FUNC key
 To access items on the page, press the CRSR key
 To cycle through the selections of an item on the page, press the 8 or 9 key
 To scroll up or down on the page when nothing is selected, press the 8 or 9 key
 To move within the page, press the ENT key
 To move to previous selection on the page, press the CLR key
 To exit the page, press the FUNC key

GTX 3X5 units may also be configured using the GTX 3X5 Install Tool. For configuration using the
GTX 3X5 Install Tool, refer to Section 3.5.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-5

Function Display

FLIGHT ID If ALLOW PILOT TO EDIT FLT ID is configured to YES, the FLIGHT ID

can be changed by the pilot at any time in normal mode. This allows the pilot/
crew to enter the specific flight ID for transmission to ATC interrogations.

UP COUNTER Timer controlled by ENT and CLR keys.

DOWN COUNTER Timer controlled by ENT, CLR, and CRSR keys. The initial count down time

is entered with the 0 – 9 keys.

FLIGHT TIMER Displays the Flight Time, controlled by the ENT key or by one of four

airborne sources (squat switch, GPS ground speed recognition, air data
airspeed recognition, or altitude increase) as configured during installation.
The timer begins when the GTX 3X5 determines that the aircraft is airborne.

TRIP TIMER Timer controlled by ENT and CLR keys.

PRESSURE ALT Displays the altitude data supplied to the GTX 3X5 in feet, hundreds of feet

(flight level), or meters, depending on configuration.

ALT MONITOR Controlled by ENT key. Activates a voice alarm and warning annunciator

when altitude limit is exceeded.

SAT/DALT Displayed when the GTX 3X5 is configured with temperature input. Displays

Static Air Temperature and Density Altitude.

CONTRAST/OFFSET Contrast is controlled by the 8 and 9 keys.

BACKLIGHT/OFFSET This page is only displayed if photocell backlighting mode is selected in

Configuration mode. Backlighting is controlled by the 8 and 9 keys.

MESSAGES Alerts crew of transponder faults, fails and advisory messages. MSG appears

when a message is generated. CRSR and ENT keys access messages for
acknowledgment and viewing.

BLUETOOTH This page is only displayed on the GTX 345/345D when configured for

Bluetooth at installation. When enabled, allows PED pairing to the GTX 345/
345D and device management for display of ADS-B In data.

INTERNAL GPS This page displays Lat/Long accuracy, number of connected satellites,

horizontal figure of merit, whether the unit is using internal GPS, and overall
status.

1090ES TX CTRL This is only displayed when the unit is configured for 1090ES OUT

CONTROL in Configuration mode to be PILOT SET. Once configured, this
can be highlighted by the CRSR key, changed by the 8 and 9 keys, and
selected by ENT key. Turns the extended squitter function on or off.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-6

3.3 GTX 33/33D and GTX 335R/335DR/345R/345DR

Figure 3-3, Figure 3-4, and Figure 3-5 show the GTX control pages associated with the GTN 6XX/7XX
and GNS 480. Refer to the specific pilot guide and cockpit reference guide for details regarding control
and function. Part numbers for these documents are listed in Table 1-1.

Figure 3-3 GTN 7XX Transponder Control

Figure 3-4 GTN 6XX Transponder Control

Figure 3-5 GNS 480 Transponder Control

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-7

3.4 GTX 335R/335DR/345R/345DR with Legacy G1000

With specific installations, the GDU 1XXX (of the G1000 system) provides control and operation of the
remote mounted GTX 335R/335DR/345R/345DR units. Figure 3-6 and Figure 3-7 display screen shots of
the GTX control pages associated with the G1000 system.

Refer to the specific aircrafts pilot guide for generic G1000 transponder control and functionality. In
addition to the generic transponder operation, functionality has changed to incorporate the GTX 3X5
interface as follows.

Functions:

GND The GND soft key is unavailable with the GTX 3X5 transponders. “XPDR GND

UNAVL” will annunciate any time the GND soft key is pressed and the unit will
revert to the previous mode the unit was in prior to the GND soft key being
pressed.

ADS-B TX The transmission of the ADS-B information is enabled/disabled by pressing the

ADS-B TX soft key. ADS-B transmission defaults to enabled at each power cycle.

In older GDU 1XXX software versions, the ADS-B TX soft key is not available;
this function defaults to enabled. Do not disable ADS-B transmission unless
requested by ATC.

Annunciations:

ADS-B Fail Any time the ADS-B Out system fails or the GPS signal is degraded, an ADS-B

Fail message will annunciate.

XPDR GND UNAVL Any time the GND soft key is pressed the advisory message will annunciate to

alert the ground mode is no longer available.

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Figure 3-6 G1000 Transponder Control

Figure 3-7 G1000 Transponder Control

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3.5 GTX 3X5 Install Tool

NOTE

NOTE

USB-A

USB-B

If the GTX 3X5 is configured to interface with a display control unit, the display control
unit must be turned off or in configuration mode prior to running the GTX 3X5 Install
Tool.

The GTX 3X5 Install Tool pages shown within this manual may reflect older GTX 3X5
Install Tool versions. Some differences in operation may be observed when comparing
information in this manual to later versions of the install tool.

The GTX 3X5 Install Tool is available for download from the Garmin
GTX 3X5 Install Tool requires a computer with available USB 2.0 ports and Microsoft Windows XP or
later.

A USB A-to-B cable is required to interface between a computer and the GTX 3X5. For additional details,
refer to Figure 3-8. To use the GTX 3X5 Install Tool, remove power from the GTX 3X5. Remove power
from the display control unit or verify it is in configuration mode. Connect the USB cable between the
GTX 3X5 and the computer. Energize the GTX 3X5 and then run the GTX 3X5 Install Tool.

Figure 3-8 USB A and USB B Connectors

The install tool is used to check equipment status, load software, and configure the unit. To put a
GTX 3X5 unit in configuration mode, change “Normal Mode” to “Configuration Mode” in the unit mode
window. Click the Set key to enter configuration mode.

Green boxes indicate a function operating correctly. Red boxes indicated a failure. Yellow boxes indicate a
fault or warning. Gray boxes indicate the presence of a pilot alert.

Dealer Resource Center. The

The bottom of the install tool displays unit information such as software version, connection status, and
unit mode. The tool will also annunciate if alerts, faults, failures, or warnings exist. The menu bar at the top
of the install tool has a GTX key and a Help key. The GTX key provides the following options:

• Save configuration

• Load configuration

• Reset configuration

• Push configuration from install tool to configuration module

•Exit

The Help key provides the following information:

• Part number

• Version number

• Copyright statement

• Software license agreements.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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3.5.1 State Page

The State page of the GTX 3X5 Install Tool reports the current mode of the GTX 3X5, Flight ID, Squawk
Code, and Pressure Altitude. This page allows selection of Ground Test and Traffic Test modes. This page
also allows selection of Standby or Operate TCAS Modes.

Figure 3-9 GTX 3X5 State Page

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Rev. 7 Page 3-11

3.5.2 Status Page

The Status page reports failures, faults, warnings, and pilot alerts. Information such as whether there is a
configuration module present is also displayed.

Figure 3-10 GTX 3X5 Status Page

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3.5.3 Configuration Group

The Configuration group contains the following pages:

 Aircraft page - configuration of basic aircraft configuration and flight ID settings
 Airframe page - configuration of basic airframe configuration and operational options settings
 Unit page - configuration of identification code, unit options, and display options
 Interfaces page - configuration of serial, A429, discretes, and HSDB settings
 Sensors page - configuration of Garmin altitude encoder, GPS, internal AHRS, and additional

sensors

 Audio page - configuration of audio options and alerts
 Display page - configuration of display and key backlight, photocell and lighting bus curves, and

default offsets

All configurable settings must match GTX System Configuration Log retained in the aircraft permanent
records.

Figure 3-11 GTX 3X5 Configuration Group

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 3-13

3.5.4 Diagnostics Group

NOTE

GTX 3X5 must be in configuration mode to view connection status or get assert log.

The Diagnostics group contains the following pages:

 DAP - reports status of the necessary data supporting ADS-B requirements
 Discretes - reports status of discrete inputs, outputs, and allows the user to override the Output pins

for testing purposes

 Connection status - reports status of A429 inputs, serial inputs, and HSDB
 Internal GPS - reports GPS acquisition status and signal strength
 Bluetooth - reports Bluetooth receiver status and paired devices
 Assert log - provides ability to download assert log for system troubleshooting

Figure 3-12 GTX 3X5 Diagnostics Group

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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3.5.5 Product Data Group

The product data group provides the following pages.

 Transponder page - displays basic system, FPGA, Boot Block, and Audio Database information
 ADS-B In page - displays basic system, FPGA, and Boot Block information
 GPS page - displays GPS and GPS loader information
 Garmin Altitude Encoder page - displays altitude encoder serial number
 Configuration page - displays configuration status of aircraft, unit, wiring, and display CRCs

Figure 3-13 GTX 3X5 Product Data Group

3.5.6 Software Upload

Refer to Section 7.3 for details.

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4 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS

4.1 Applicability .....................................................................................................................................4-2

4.2 Airworthiness Limitations ................................................................................................................4-2

4.3 Servicing Information .......................................................................................................................4-3

4.3.1 On Condition Servicing..............................................................................................................4-3

4.3.2 Special Tools ..............................................................................................................................4-3

4.4 Maintenance Intervals.......................................................................................................................4-4

4.5 Visual Inspection ..............................................................................................................................4-5

4.6 Electrical Bonding Test ....................................................................................................................4-7

4.7 Additional Instructions .....................................................................................................................4-7

This section provides Instructions for Continued Airworthiness for the GTX 33X and GTX 3X5 with
ADS-B installation. This section satisfies the requirements for continued airworthiness as defined by 14
CFR Part 23.1529 and Part 23 appendix G. Information in this section is required to maintain the continued
airworthiness of the GTX 33X and GTX 3X5 as installed under this AML STC.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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4.3 Servicing Information

GTX 33X and GTX 3X5 LRU maintenance is “on condition” only. Component-level overhaul is not
required for the GTX 33X and GTX 3X5 with ADS-B installation.

4.3.1 On Condition Servicing

On Condition replacement and/or servicing should occur when an item exhibits conditions, symptoms,
and/or abnormalities as defined in Section 5 of this manual. Replacement and/or servicing should be made
only after the technician troubleshoots the system by using the guidance in this manual along with common
avionics maintenance practices.

4.3.2 Special Tools

The following tools are needed to perform maintenance tasks.

 Calibrated milliohm meter with an accuracy of +
 Calibrated transponder ramp tester
 Calibrated Pitot/static ramp tester
 GTX 3X5 Install Tool (remote units only)
 50 Ω 5 watt antenna load

0.1 milliohm or better

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 4-3

4.4 Maintenance Intervals

NOTE

Table 4-1 shows systems and components, installed by this STC, which must undergo tests or checks at
specific intervals. The inspections based on calendar elapsed time have specifically stated intervals.

The maintenance intervals listed in the table below must be adhered to for each installed
GTX.

Table 4-1 Maintenance Intervals

Item Description/Procedure Section Interval

Equipment Removal
and Reinstallation

Cleaning

Antenna Visual
Inspection

Lightning Strike ­Actual or Suspected

Removal and reinstallation of GTX
LRUs.

The GTX 330 and GTX 335/335D/345/
345D display and bezel may be
cleaned periodically.

Cleaning is accomplished using a soft
cotton cloth dampened with clean
water.

DO NOT use any chemical cleaning
agents. Avoid scratching the surface of
the display.

Removal and replacement.

Inspect the coaxial cable connections,
GTX bonding hardware (including
bonding straps and tape), antenna, and
surrounding areas.

The GTX 33/330 and GTX 3X5 receiver
sensitivity must be tested and shown to
comply with Title 14 CFR Part 43
Appendix F.

6

N/A

4.5

4.5

4.

On Condition

On Condition

On Condition

On Condition

On Condition

Testing

Equipment Visual
Inspection

Testing

Electrical Bonding Test

The GTX 33/330 and GTX 3X5 must be
tested and shown to comply with Title
14 CFR Part 91.227.

A visual inspection of the equipment
installed by this STC must be
performed.

The GTX 33/330 and GTX 3X5 must be
tested and shown to comply with Title
14 CFR Part 91.411, 91.413, and Part
43 Appendix E and F.

An electrical bonding test must be
performed on equipment installed by
this STC.

8.7

4.5

4.

4.6

Replacement of GPS
Position source(s).

12 Calendar Months

Refer to Title 14 CFR
Part 91.411, 91.413,
and Part 43 Appendix
E and F.

10 Years or 2000
hours

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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4.5 Visual Inspection

Perform a visual inspection in accordance with requirements in this section. Check for corrosion, damage,
or other defects for each of the installed items. Replace any damaged parts as required. Inspection may
require the temporary removal of a unit or units to gain access to connectors. Follow guidance in Section 6
for equipment removal and replacement. Refer to Appendix A of this manual for equipment locations.
Refer to the specific Aircraft Maintenance Manual for instructions on removing any access panels.

GTX 330/330D/335/335D/345/345D Visual Inspection

During normal aircraft inspections not to exceed 12 calendar month intervals, conduct a visual inspection
of the GTX 330/330D/335/335D/345/345D installation in the following locations.

Instrument Panel

1. Inspect all GTX 330/330D/335/335D/345/345D keys for legibility of labels and markings.

2. Inspect GTX 330/330D/335/335D/345/345D units for security of attachment.

3. Inspect mounting rack and hardware for integrity.

a. Verify the racks, fasteners, and support structure are in good condition and securely fastened.

b. Inspect for signs of corrosion.

c. For composite aircraft, inspect any aluminum foil tape used to ground the GTX and verify that

it is not torn, damaged, or showing signs of corrosion. If any of these occur then the tape must
be replaced. Refer to Appendix B for details.

4. Inspect any bonding straps for corrosion, loose connections, or signs of damage. Refer to
Appendix B for details.

5. Inspect the condition of the wiring harnesses and coaxial cables.

a. Inspect all instrument panel wiring and coax for chafing, damage, proper routing of wire

bundles and security of attachment in accordance with AC 43.13-1B, chapter 11, section 8,
paragraph 11-96. Pay particular attention to possible areas of chafing.

b. Verify that the harness shows no signs of cracking, chafing, abrasion, melting, or any other

form of damage.

c. Inspect the GTX 330/330D/335/335D/345/345D connectors for corrosion or other defects.

Check the integrity of the shield block ground attachments to the harness connector assembly
as well as the integrity of the individual shields and their attachment.

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Rev. 7 Page 4-5

GTX 33/33D/335R/335DR/345R/345DR Visual Inspection

During normal aircraft inspections not to exceed 12 calendar month intervals, conduct a visual inspection
of the GTX 33/33D/335R/335DR/345R/345DR installation in the following locations.

Remote Mount Rack

1. Inspect GTX 33/33D/335R/335DR/345R/345DR units for security of attachment.

2. Inspect mounting rack and hardware for integrity.

a. Verify the racks, fasteners, and support structure are in good condition and are securely

fastened.

b. Inspect for signs of corrosion.

c. For composite aircraft, inspect any aluminum foil tape used to ground the GTX and verify that

it is not torn, damaged, or showing signs of corrosion. If any of these occur then the tape must
be replaced. Refer to Appendix B for details.

3. Inspect any bonding straps for corrosion, loose connections, or signs of damage. Refer to
Appendix B for details.

4. Inspect the condition of the wiring harnesses and coaxial cables.

a. Verify that all wiring and cables are securely fastened.

b. Verify that the harness shows no signs of cracking, chaffing, abrasion, melting, or any other

form of damage.

c. Inspect the GTX 33/33D/335R/335DR/345R/345DR connectors for corrosion or other

defects. Check the integrity of the shield block ground attachments to the harness connector
assembly as well as the integrity of the individual shields and their attachment.

Antenna Visual Inspection

During normal aircraft inspections not to exceed 12 calendar month intervals, conduct a visual inspection
of the transponder antennas for the following.

1. Erosion, cracks, dents, or broken antenna. If these conditions are present, antenna must be
replaced. Refer to antenna manufacturer’s replacement instructions for details.

2. If the attachment is not secure, re-work the installation and complete electrical bonding test
specified in Section 4.6.

3. Condition of base seals. In the event the antenna seal shows sign of damage or decomposition, re­seal and complete the electrical bonding test specified in Section 4.6.

Post Lightning Strike Inspection

A post lightning strike inspection must be performed for a suspected or actual lightning strike to antennas
or any temperature sensor connected to the GTX unit. Inspect antenna or sensor and surrounding
installation to verify that structural damage has not occurred around the areas where lightning may have
attached. If there is visible sign of damage to the antenna or sensor, then it should be replaced.

Inspect the antenna coax connection to GTX unit, grounding hardware, bonding straps or tape, and
surrounding areas of the remotely mounted GTX to verify damage has not occurred. Repair any damaged
areas and components, then complete the electrical bonding test specified in Section 4.6.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 4-6

4.6 Electrical Bonding Test

1. Disconnect the antenna coaxial cable from the GTX 33X or GTX 3X5.

2. Disconnect all connectors from the GTX 33X or GTX 3X5.

3. Measure the DC resistance between each of the following test points and the aircraft ground
reference as defined in Table B-1 and verify the resistance is less than or equal to the appropriate
periodic test resistance value.

 Top metal case of GTX 330/330D/335/335D/345/345D #1 (if installed)

 Top metal case of GTX 330/330D/335/335D/345/345D #2 (if installed)

 GTX 33/33D/335R/335DR/345R/345DR #1 chassis (if installed)

 GTX 33/33D/335R/335DR/345R/345DR #2 chassis (if installed)

4. If the resistance is more than the periodic test resistance value in Table B-1, the bond must be
improved enough to meet the reconditioned resistance value.

4.7 Additional Instructions

Electrical load information for the GTX is provided in Section 2.6.

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5 TROUBLESHOOTING

5.1 GTX General Troubleshooting .........................................................................................................5-2

5.2 GTX Failure Annunciations..............................................................................................................5-4

5.3 GTX 33X Connector Pinout Information .......................................................................................5-11

5.3.1 GTX 33X (J3301).....................................................................................................................5-11

5.3.2 Altitude Functions ....................................................................................................................5-13

5.3.3 Discrete Functions ....................................................................................................................5-13

5.3.4 RS-232 Input/Output ................................................................................................................5-14

5.3.5 ARINC 429 Input/Output .........................................................................................................5-14

5.4 GTX 3X5 Connector Pinout Information .......................................................................................5-15

5.4.1 GTX 3X5 (J3251).....................................................................................................................5-15

5.4.2 GTX 345/345D/345R/345DR (J3252) .....................................................................................5-17

5.4.3 Altitude Functions ....................................................................................................................5-18

5.4.4 Discrete Functions ....................................................................................................................5-19

5.4.5 RS-232 Input/Output ................................................................................................................5-21

5.4.6 ARINC 429 Input/Output .........................................................................................................5-21

5.4.7 RS-422 Out...............................................................................................................................5-21

5.4.8 HSDB Input/Output..................................................................................................................5-22

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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5.1 GTX General Troubleshooting

This section provides information to assist troubleshooting if problems occur after completing
maintenance. Refer to the GTX System Configuration Log retained in the aircraft permanent records for a
list of the interfaced equipment and system configuration data. When troubleshooting the GTX, refer to the
wire routing drawings and interconnect wiring diagrams that are retained in the aircraft permanent records.

The following table describes possible symptoms associated with the Garmin transponders and provides
corresponding actions for troubleshooting.

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Rev. 7 Page 5-2

Check and verify the

integrity of the

transponder-altitude

encoder interface,

including wiring and

altitude encoder

operation

Check and verify

integrity of the

antenna installation,

ground planes, and

coaxial cable

Ensure the XPDR

circuit breaker is

closed

Test coaxial cables for

insertion loss and VSWR.

VSWR should be checked

with an in-line type VSWR/

wattmeter inserted in the
coaxial transmission line

between the transponder and

the antenna. The VSWR
should be 1.5:1 at 1090 MHz
or less. Insertion loss should

be less than 1.5 dB at 1090

MHz

GTX Symptom

Transponder audio too quiet/

loud

Incorrect Mode S aircraft

data transm itted

Transponder will not turn

on

Transponder will not come

out of standby

Check for proper

electrical bonding/

grounding of the

antenna installation

Corrective

Action

Corrective

Action

Corrective

Action

Corrective

Action

Ensure transponder

is fully seated and

mated to the

connectors in the

mounting rack

Corrective

Action

Corrective

Action

If fault still exists,

contact Garmin.

Loss of, or incorrect altitude
reporting by the transponder

Verify transponder

select switch position,

(#1 or #2) if installed

Check the

configuration mode

settings and reset if

necessary

Verify that the GTX

volume setting is at or

above the minimum

required setting

Poor transponder

performance. Weak or

intermittent radar contact

reported by ATC

Verify connections

for power and ground

Verify the unswitched

audio input at the

audio panel setting is

at or above the

minimum required

setting

Check the altitude

source configuration

on the GTX. Verify
primary and secondary
sources are configured

properly.

Verify the Flight ID and

ICAO address are

configured properly

Verify the Tail number

and ICAO address are

properly configured

Figure 5-1 GTX (All Models) Transponder Troubleshooting

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Rev. 7 Page 5-3

5.2 GTX Failure Annunciations

Ensure the aircraft has a clear view of

the sky

GTX 330 Failure

Messages

NO ADSB

Transponder FAIL

message

Fatal Error Page Displayed

Cause

Corrective

Action

If fault still exists,

contact Garmin.

Ensure position source (GPS) is

powered and receiving valid GPS

position data

Ensure ADS-B TX is ON. This option

is only available if ADS-B TX is

configured for PILOT SET

Corrective

Action

Corrective

Action

Cause Cause

The internal transmit or

squitter monitors have

detected a failure

The transponder has

insufficient data to support

ADS-B Out transmission

The transponder has failed

the internal power up

integrity check

Reset the transponder. Check

connections, wiring, and coax cables

Reload software

Reset the transponder. Check

connections, wiring, and coax cables

Reload software

Figure 5-2 GTX 330/330D Transponder Failure/Fault Messages

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-4

Verify ADS -B TX is on

and GPS source is

receiving valid GPS

position data

Verify GPS source

configuration is IAW

the Installation

Guidance

GTX 33 Failure

Messages

TRANSPONDER 1 –

ADSB is not

transmitting position

TRANSPONDER 2 –

ADSB is not

transmitting position

Verify the aircraft has a

clear view of the sky

The transponder has

insufficient data to

support ADS-B Out

transmission

Cause

The transponders are

configured for different

Mode S addresses

Corrective

Action

Corrective

Action

If fault s till exists ,

return to Garmin.

TRANSPONDER –

Transponder 1 and 2

Mode S addresses do

not match

Cause

The transponder is

reporting a system

failure

Corrective

Action

TRANSPONDER 1 –

Transponder 1 needs

service

Cause

The transponder is
reporting a system

failure

Corrective

Action

TRANSPONDER 2 –

Transponder 2 needs

service

Verify the Mode S

address for each

transponder and that

they match.

Cause

Verify RS-232 wiring

between GTN/GNS

and GTX

Check configuration of

GTX and GTN/GNS

TRANSPONDER 1 –

Transponder 1 is

inoperative or

connection to GTN/

GNS is lost

TRANSPONDER 2 –

Transponder 2 is

inoperative or

connection to GTN/

GNS is lost

If two transponders are

installed, ensure both

units are powered on

The GTN/GNS cannot
communicate with the

transponder or the

transponder is

reporting a system

failure

Corrective

Action

Cause Cause Cause

The GTN cannot

communica te with the

transponder or the

transponder is

reporting a system

failure

If two transponders are

installed, ensure both
units are powered on

Check configuration of

GTX and GTN/GNS

Verify RS-232 wiring

between GTN/GNS

and GTX

The transponder has

insufficient data to

support ADS-B Out

transmission

Corrective

Action

Corrective

Action

Verify ADS-B TX is on

and GPS source is

receiv ing valid GPS

position data

Verify GPS source

configuration is IAW

the Installation

Guidance

Verify the aircraft has a

clear view of the sky

Check configuration of

GTX and GTN/GNS

Check configuration of

GTX and GTN/GNS

Re-install the la test

software

Re-configure the GTX

Re-install the latest

software

Re-configure the GTX

Figure 5-3 GTX 33/33D Transponder Failure/Fault Messages

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-5

GTX 3X5 Messages

If fa ult s till exists,

contact Garmin.

Transponder

Or

1090 ADS-B

Out

1090 MHz

Transm itter

Failure

1030 MHz

Rece ive r Fa ilure

Failure

IC AO A dd ress

Failure

- Lo ss, d am aged,
inc orre ct w irin g

- Incorre ct antenna

- Inte rnal fa ilure

ICA O add res s is

incorrect

Cause

Verify transponder

antenna,

connections, and

coa x ins tallation

Insp ect

suppression bus

wiring

Insp ect wiring

Re load softw are

Reset config and

config module

Reconfigure unit

Verify transponder

antenna,

connections, and

coa x ins tallation

Insp ect

suppression bus

wiring

Insp ect wiring

Re load softw are

Re set c onfig and

config module

Reconfigure unit

En ter p rope r ICAO

address.

Re load softw are

Corrective

Action

Transponder

Or

1090 ADS-B

Out

Fa ilure

Cause

- Loss, damaged,
inc orr ec t w iring

- Inco rrec t ante nna

- Inte rnal fa ilure

Corrective

Action

Transponder

Or

1090 ADS-B

Out

Fa ilure

Cause

Corrective

Action

Configuration

Fa ilure

Transponder

configuration data

is inv alid or
inc om ple te

Reload software

Re set c onfig and

co nfig modu le

Reconfigure unit

Ve rify the GTX

Insta ll tool

configuration

sum mary, correct

any errors

Transponder

Or

1090 ADS-B

Out

Failure

Cause

Corrective

Action

C alib ration

Fa ilure

Factory

transponder

calibration data

inv alid

Reload software

Reset config and

config module

Reconfigure unit

Verify transponder

antenna,

connections, and

coax installaiton

Insp ect wiring ,

suppression bus,

and connections

Transponder

Or

1090 ADS-B

Out

Fa ilure

Cause

Corrective

Action

E lec trica l F ailu re

Internal v oltag e

mis-com pare with

the unit

Reload software

Re set c onfig and

co nfig modu le

Reconfigure unit

Ve rify all w iring,

shorts/opens.

Ve rify po we r an d

ground

connections

Transponder

Or

1090 ADS-B

Out

Fa ilure

Cause

Corrective

Action

Frequency Lock

Fa ilure

FP G A ha s an erro r

Possible internal

hard ware issue

Reload software

Reset config and

config module

Reconfigure unit

Verify transponder

antenna,

connections, and

coax installation

Insp ect wiring ,

suppression bus,

and connections

Transponder

Or

1090 ADS-B

Out

Fa ilure

Cause

Corrective

Action

Squitter Monitor

Fa ilure

Erro r gene rating

Squ itter replies

Possible internal

hard ware issue

Reload software

Re set c onfig and

config module

Reconfigure unit

Verify transponder

antenna,

connections, and

coax installation

Insp ect wiring ,

suppression bus,

and connections

Transponder

Or

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Re set c onfig and

config module

Reconfigure unit

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-6

Figure 5-4 GTX 3X5 Transponder Alerts

Sheet 1 of 5

GTX 3X5 Messages

If fault still exists,

contact Garmin.

Transmit Monitor

Failure

FP GA Fa ilure

- 1090MHz
transmission
failure s,

- Internal hardware
problem

- Wiring p roblem

- Incompatible
antenna

FPGA software did

not load properly

Reload software

Reset config and

config module

Reconfigure unit

Verify antenna,

connections, and

coax installation

Insp ect wiring,
suppression bus,
and connections

Reload software

Reset config and

config module

Reconfigure unit

Verify antenna,

connections, and

coax installation

Inspect wiring,

suppression bus,

and connections

Transponder

Or

1090 ADS-B

Out

Transponder

Or

1090 ADS-B

Out

Failure

Failure

Cause Cause

Corrective

Action

Corrective

Action

Maximum

Temperature

Exceeded

Minimum

Temperature

Exceeded

Low Temperature

Failure

High

Temperature

Failure

Internal

Temperature has

exceeded limits.

Possible internal

damage may have

occured

Bring GTX within

operating

temperature listed

on the EQF

Bring GTX within

operating

temperature listed

on the EQF

Internal

Temperature has

exceeded limits.

Possible internal

damage may have

occured

Failu re Failure

Cause Cause

Corrective

Action

Corrective

Action

High

Temperature

Failure

Low Temperature

Failure

Internal

Temperature has

exceeded limits,

possible internal

damage may have

occurred

Bring GTX within

operating

temperature listed

on the EQF

Bring GTX within

operating

temperature listed

on the EQF

Internal

Temperature has

exceeded limits,
possible internal

damage may have

occurred

Transponder

Or

1090 ADS-B

Out

Transponder

Or

1090 ADS-B

Out

Failure Failure

Cause Cause

Corrective

Action

Corrective

Action

RAM Failure

Software load

issue or internal

hardware issue

Reload software

Transponder

Or

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Transponder

FPGA ROM

Failure

FPGA software

load issue

Reload software

Transponder

Or

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Transponder
RO M Failu re

Software load

issue

Reload software

Transponder

Or

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Figure 5-4 GTX 3X5 Transponder Alerts

Sheet 2 of 5

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-7

GTX 3X5 Messages

If fau lt still ex ists ,

contact Garmin.

Pressure

Altitude

Pressure

Altitude Input

Warning

Ground Test

Ground Test

Mode

Pressure altitude

is not va lid

Verify GTX and
pressure sensor are
properly configured

Verify w iring from

pressure sensor

Verify p ressure

sensor is functioning

If using the GA E,

verify connections

and then recalibrate

Reload software

System in ground

test mode

Power cycle the GTX

Warning

Cause

Corrective

Action

Alert

Cause

Corrective

Action

TAS/TCAS

TAS/TCAS

Inpu t Wa rning

TAS/TCAS is configured
on the GTX and no data

is received or the TAS/

TCAS system is reporting

a failure .

Verify TAS/TCAS

system has the required

and valid data (i.e.

Position, Altitude,

Heading, etc.)

Verify w iring w ith TAS/

TCAS system

Verify th e TAS /TCA S is

configured properly

Verify the TAS/TCAS
system has not failed

Warning

Cause

Corrective

Action

ADS-B

Position Input

No ADS-B

Position Input

Warning

GPS position

unavailable with ADS-B

In and/or Out enabled.

(for ADS-B Out, the unit

is not in standby)

Verify GPS antenna is

SBAS compatible

Verify position source is

available, powered on,

and properly configured

Verify GPS antenna
has cle ar view of the

sky

Warning

Cause

Corrective

Action

Reset config and

config module

Reconfigure unit

ADS-B In

Traffic

Alerting

CSA Fault

Traffic

Traffic

Processing

Fault

Traffic

AD S-B In

Communicatio

n Fault

ADS-B IN processing is enabled and
the input data does not meet the
performance specifications.

- GPS horizontal position unavailable

- GPS velocity unavailable

- GP S time u navailab le

- HFOM must be better than 0.5NM

- Pressure altitude unavailable or GPS
altitude and VFOM worse than 45m

Verify valid GPS antenna has

clear view of the sky

Position source is available,

properly configured and powered

Verify ADS-B In traffic is properly
installed and configured,
display source,
heading source,
GPS source
Are all configured properly

Reset configuration and

configuration module, then

reconfigure unit

Reload software

ADS-B In is enabled and an additional
fault ha s occure d.

- ADS-B / ADS-R / TIS-B Fault

- TAS/TCAS Input Warning

- CSA Fault

- GPS Fault

- Pressure Altitude Warning

- ADS -B In E lectrical Fa ult

- Internal communication between the
main and ADS-B boards

Insp ect co mpa tibility of

transponder antenna and

connections

Verify the position source is

available, powered on and

properly configured

Reset configuration and

configuration module, then

reconfigure unit

Reload software

Verify TAS/TCAS system is

not failed

ADS-B In is enabled and an additional
fault ha s occure d.

- ADS -B / AD S-R / T IS-B Fa ult

- TAS/TCAS Input Warning

- CSA Fault

- GPS Fault

- Pressure Altitude Warning

- ADS -B In E lectrical Fa ult

- Internal communication between the
main and ADS-B boards

Fault

Cause

Corrective

Action

Fault Fault

Cause Cause

Corrective

Action

Corrective

Action

Insp ect co mpa tibility of

transponder antenna and

connections

Reset configuration and

configuration module, then

reconfigure unit

Reload software

Verify TAS/TCAS system is

not faile d

Verify the position source is

available, powered on and

properly configured

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-8

Figure 5-4 GTX 3X5 Transponder Alerts

Sheet 3 of 5

GTX 3X5 Messages

If fault still exists ,

contact Garmin.

ADS-B IN

ADS-B/ADS-R/

TIS-B Fault

1090

ADS-B In

1090 RX Fault

UAT

ADS-B In

978 RX Fault

ADS-B In enabled

and both 1090

MHz and 978 MHz

receivers failed

Verify antenna is

compatible

Reload software

Inspect all wiring,

and coaxial cables

ADS-B In enabled

and the 1090 MHz

receiver failed

Verify antenna is

com pa tible

Reload software

Inspect all wiring,

and coaxial cables

ADS-B In enabled

and the 978 MHz

receiver failed

Inspect

compatibility of

transponder

antenna and

connections

Reload software

Fault

Cause

Corrective

Action

Fault

Cause

Corrective

Action

Fault

Cause

Corrective

Action

FIS-B

Weather

978 RX Fault

FIS-B

Weather

ADS-B In

Communicatio

n Fault

FIS-B enabled

and the 978 MHz

receiver failed

Inspect

com pa tibility of

transponder
antenna and
connections

FIS-B enabled and

the 978 MHz

receiver failed

Inspect

com pa tibility of

transponder

antenna and

connections

Reload software

Fault

Cause

Corrective

Action

Fault

Cause

Corrective

Action

ADS-B In

Configuration

Fault

ADS-B In

configuration data

did not load or is

invalid

Service Soon

Fault

Cause

Corrective

Action

ADS-B In

Electrical Fault

ADS-B In

Calibration

Fault

Reload software

Electrical fault with

the ADS-B board.

Possible internal

hardware problem.

Check wiring

Factory ADS-B In
calibration data is

inva lid

Reload software

Service SoonService Soon

Fault

Cause

Fault

Cause

Corrective

Action

Corrective

Action

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reload software

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reload software

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-9

Figure 5-4 GTX 3X5 Transponder Alerts

Sheet 4 of 5

GTX 3X5 Messages

If fault still ex ists,

contact Garmin.

GPS Fault

GAE

Calibration

Fault

Backlight

Calibration

Fault

Configuration

Module Fault

- No GPS data
available.

- Internal G PS fault

- Not connected to a
valid SBAS/GPS
source

Verify GPS

antenna is SBAS

compatible

Verify position

source is available

and properly

configured

Verify GPS

antenna has clear

view of the sky

Gar min A ltitude
Encoder (GAE)

calibration data is

invalid

Calibrate GAE

Factory calibration

for the dis play is

invalid

Verify lighting
configuration

Failure of the

configuration

module

Verify module is

installed and

wiring is correct

Service SoonService Soon

Fault

Cause

Fault

Cause

Service Soon Service Soon

Fault

Cause

Fault

Cause

Corrective

Action

Corrective

Action

Corrective

Action

Corrective

Action

Audio ROM

Fault

Non-volatile

Memory Fault

Audio database

did not load or is

invalid

Non-volatile data
did not load or is

invalid

Service SoonService Soon

FaultFault

CauseCause

Corrective

Action

Corrective

Action

Service Soon

Suppression

Bus Fault

Fault on the

suppression bus

Check for

incom patib le LR U

on suppression

line (D ME)

Verify su ppression

bus wiring for

shorts or opens

Fault

Cause

Corrective

Action

ADS-B In

FPGA ROM

Fault

ADS-B In FPGA

software did not

load or is invalid

Service Soon

Fault

Cause

Corrective

Action

Reset config and

config module

Reconfigure unit

AD S-B In ROM

Fault

ADS -B In softw are

did not load or is

invalid

Reload software

Service Soon

Fault

Cause

Corrective

Action

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module

Reconfigure unit

Reload software Reload software Reload software

Reset config and

config module

Reconfigure unit

Reload software

Reset config and

config module

Reconfigure unit

Reload software

Reset config and

config module

Reconfigure unit

Reload software

Figure 5-4 GTX 3X5 Transponder Alerts

Sheet 5 of 5

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-10

5.3 GTX 33X Connector Pinout Information

59 58 57 56

5

5

54 53 52

51

43

44

50

49

48 47

46 45

62

61

60

25 24 23 22

26

27

282930

313233

34

353637

3839

404142

1

2

345678

9101113

14151617

12

1920

21

18

5.3.1 GTX 33X (J3301)

Figure 5-5 Rear View, Connector P3301

Table 5-1 GTX 33X Pinout

Pin GTX 33/33D Pin Name GTX 330/330D Pin Name I/O

1 RESERVED AVIONICS MASTER ON SELECT IN

2 ALTITUDE A1 ALTITUDE A1 IN

3 ALTITUDE C2 ALTITUDE C2 IN

4 ALTITUDE A2 ALTITUDE A2 IN

5 ALTITUDE A4 ALTITUDE A4 IN

6 ALTITUDE C4 ALTITUDE C4 IN

7 ALTITUDE B1 ALTITUDE B1 IN

8 ALTITUDE C1 ALTITUDE C1 IN

9 ALTITUDE B2 ALTITUDE B2 IN

10 ALTITUDE B4 ALTITUDE B4 IN

11 ALTITUDE D4 ALTITUDE D4 IN

12 EXTERNAL IDENT SELECT* EXTERNAL IDENT SELECT* IN

13 EXTERNAL STANDBY SELECT* EXTERNAL STANDBY SELECT* IN

14 NOT USED 28 V LIGHTING BUS HI IN

15 AUDIO OUT HI AUDIO OUT HI OUT

16 AUDIO OUT LO AUDIO OUT LO OUT

17 SQUAT SWITCH IN SQUAT SWITCH IN IN

18 RESERVED RESERVED --

19 ALTITUDE ALERT ANNUNCIATE* ALTITUDE ALERT ANNUNCIATE* OUT

20 RESERVED RESERVED --

21 AIRCRAFT POWER 1 AIRCRAFT POWER 1 IN

22 RS-232 IN 1 RS-232 IN 1 IN

23 RS-232 OUT 1 RS-232 OUT 1 OUT

24 RS-232 IN 2 RS-232 IN 2 IN

25 RS-232 OUT 2 RS-232 OUT 2 OUT

26 ARINC 429 IN 3 A ARINC 429 IN 3 A IN

27 POWER GROUND POWER GROUND --

28 ARINC 429 OUT 2 B ARINC 429 OUT 2 B OUT

29 ARINC 429 IN 3 B ARINC 429 IN 3 B IN

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-11

Pin GTX 33/33D Pin Name GTX 330/330D Pin Name I/O

30 ARINC 429 OUT 2 A ARINC 429 OUT 2 A OUT

31 EXTERNAL SUPPRESSION I/O EXTERNAL SUPPRESSION I/O I/O

32 ARINC 429 IN 1 A ARINC 429 IN 1 A IN

33 ARINC 429 IN 2 A ARINC 429 IN 2 A IN

34 ARINC 429 OUT 1 B ARINC 429 OUT 1 B OUT

35 ARINC 429 IN 1 B ARINC 429 IN 1 B IN

36 ARINC 429 IN 2 B ARINC 429 IN 2 B IN

37 ARINC 429 OUT 1 A ARINC 429 OUT 1 A OUT

38 RESERVED RESERVED --

39 RESERVED RESERVED --

40 SPARE SPARE --

41 CURRENT TEMPERATURE PROBE OUT CURRENT TEMPERATURE PROBE OUT OUT

42 AIRCRAFT POWER 1 AIRCRAFT POWER 1 IN

43 POWER GROUND POWER GROUND --

44 CURRENT TEMPERATURE PROBE IN CURRENT TEMPERATURE PROBE IN IN

45 NOT USED 14 V/5 V LIGHTING BUS HI IN

46 TIS CONNECT SELECT* TIS CONNECT SELECT* IN

47 AUDIO MUTE SELECT* AUDIO MUTE SELECT* IN

48 ARINC 429 IN 4 A ARINC 429 IN 4 A IN

49 ARINC 429 IN 4 B ARINC 429 IN 4 B IN

50 ALTITUDE COMMON (GROUND) ALTITUDE COMMON (GROUND) IN

51 SIGNAL GROUND SIGNAL GROUND --

52 RESERVED RESERVED --

53 RESERVED RESERVED --

54 XPDR REMOTE POWER OFF RESERVED IN

55 NOT USED SPARE --

56 AIRCRAFT POWER 2 AIRCRAFT POWER 2 IN

57 NOT USED SPARE --

58 SIGNAL GROUND RESERVED --

59 NOT USED SPARE --

60 AIRCRAFT POWER 2 AIRCRAFT POWER 2 IN

61 NOT USED SPARE --

62 SWITCHED POWER OUT SWITCHED POWER OUT OUT

* Denotes Active-Low (Ground to activate)

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-12

5.3.2 Altitude Functions

Gillham code altitude inputs are considered active if either the voltage to ground is < 1.9 V or the
resistance to ground is < 375 . These inputs are considered inactive if the voltage to ground is
11-33 VDC.

Table 5-2 GTX 33X Encoded Altitude Pin Assignments

Pin Name Pin Number I/O Unit (33X)

ALTITUDE D4 11 IN Both

ALTITUDE A1 2 IN Both

ALTITUDE A2 4 IN Both

ALTITUDE A4 5 IN Both

ALTITUDE B1 7 IN Both

ALTITUDE B2 9 IN Both

ALTITUDE B4 10 IN Both

ALTITUDE C1 8 IN Both

ALTITUDE C2 3 IN Both

ALTITUDE C4 6 IN Both

ALTITUDE COMMON 50 -- Both

5.3.3 Discrete Functions

Discrete Outputs

Table 5-3 GTX 33/330 Discrete Outputs

Pin Name Pin Number I/O Unit (33X)

ALTITUDE ALERT ANNUNCIATE* 19 OUT Both

EXTERNAL SUPPRESSION I/O 31 I/O Both

*This output is considered active if either the voltage to ground is < 1.9 V or the resistance to ground is

< 375 Ω. This output is considered inactive if the voltage to ground is 11-33 Vdc.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-13

Discrete Inputs

Table 5-4 GTX 33/330 Discrete Inputs

Pin Name Pin Number I/O Unit (33X) Connector

AVIONICS MASTER ON SELECT 1 IN 330 Only P3301

EXTERNAL IDENT SELECT* 12 IN Both P3301

EXTERNAL STANDBY SELECT* 13 IN Both P3301

SQUAT SWITCH IN 17 IN Both P3301

TIS CONNECT SELECT* 46 IN Both P3301

AUDIO MUTE SELECT* 47 IN Both P3301

* INACTIVE: 10 ≤ Vin ≤ 33 VDC or Rin ≥ 100 kΩ (Open)

ACTIVE: Vin ≤ 1.9 VDC with ≥75 uA sink current, or Rin ≤ 375 Ω (GND)

Sink current is internally limited to 200 uA max for a grounded input.

5.3.4 RS-232 Input/Output

Table 5-5 GTX 33/330 RS-232 Connections

Pin Name Pin Number I/O Unit (33X)

RS-232 OUT 1 23 OUT Both

RS-232 IN 1 22 IN Both

RS-232 OUT 2 25 OUT Both

RS-232 IN 2 24 IN Both

5.3.5 ARINC 429 Input/Output

Figure 5-6 GTX 33/330 ARINC 429 Connections

Pin Name Pin Number I/O Unit (33X)

ARINC 429 OUT 1A 37 Out Both

ARINC 429 OUT 1B 34 Out Both

ARINC 429 IN 1A 32 In Both

ARINC 429 IN 1B 35 In Both

ARINC 429 IN 2A 33 In Both

ARINC 429 IN 2B 36 In Both

ARINC 429 OUT 2A 30 Out Both

ARINC 429 OUT 2B 28 Out Both

ARINC 429 IN 3A 26 In Both

ARINC 429 IN 3B 29 In Both

ARINC 429 IN 4A 48 In Both

ARINC 429 IN 4B 49 In Both

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-14

5.4 GTX 3X5 Connector Pinout Information

59 58 57 56

5

5

54 53 52

51

43

44

50

49

48 47

46 45

62

61

60

25 24 23 22

26

27

282930

313233

34

353637

3839

404142

1

2

345678

9101113

14151617

12

1920

21

18

5.4.1 GTX 3X5 (J3251)

Figure 5-7 Rear View, Connector J3251

Table 5-6 J3251 Pinout

Pin GTX 3X5 Pin Name I/O

1 ALT ENCODER/CONFIG MODULE CLOCK IN/OUT

2 USB DATA HI IN/OUT

3 TEMP PROBE IN IN

4 TIME MARK A OUT

5 ARINC 429 OUT A OUT

6 ARINC 426 OUT B OUT

7 RS-232 OUT 3 OUT

8 RS-232 OUT 2 OUT

9 RS-232 OUT 1 OUT

10 ALITTUDE A1 IN

11 ALTITUDE B1 IN

12 ALTITUDE C1 IN

13 ALTITUDE D4 IN

14 EXTERNAL STANDBY SELECT IN

15 CONFIGURABLE DISCRETE 1 IN/OUT

16 CONFIGURABLE DISCRETE 2 IN/OUT

17 XPDR FAIL 1 OUT

18 EXTERNAL SUPPRESSION IN/OUT

19 LIGHTING BUS HI IN

20 AIRCRAFT GROUND IN

21 AIRCRAFT POWER 1 IN

22 ALT ENCODER/CONFIG MODULE DATA IN/OUT

23 ALT ENCODER/CONFIG MODULE GND IN

24 USB DATA LO IN/OUT

25 TEMP PROBE OUT OUT

26 TIME MARK B OUT

27 ARINC 426 IN 1A IN

28 ARINC 429 IN 1B IN

29 RS-232 IN 3 IN

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-15

Pin GTX 3X5 Pin Name I/O

30 RS-232 IN 2 IN

31 RS-232 IN 1 IN

32 ALTITUDE A2 IN

33 ALTITUDE B2 IN

34 ALTITUDE C2 IN

35 RESERVED IN

36 EXTERNAL IDENT SELECT IN

37 AUDIO INHIBIT 2 IN

38 POWER CONTROL IN

39 SWITCHED POWER OUT OUT

40 LIGHTING BUS LO IN

41 AIRCRAFT GROUND --

42 AIRCRAFT POWER 1 --

43 ALT ENCODER/CONFIG MODULE POWER --

44 USB VBUS POWER IN/OUT

45 USB GND --

46 AUDIO OUT HI OUT

47 AUDIO OUT LO OUT

48 ARINC 429 IN 2A IN

49 ARINC 429 IN 2B IN

50 RS-232 GND 3 --

51 RS-232 GND 2 --

52 RS-232 GND 1 --

53 ALTITUDE A4 IN

54 ALTITUDE B4 IN

55 ALTITUDE C4 IN

56 ALTITUDE GROUND --

57 SQUAT SWITCH IN

58 AIR DATA SELECT IN

59 POWER CONFIG IN

60 GPS KEEP ALIVE --

61 AIRCRAFT POWER 2 --

62 AIRCRAFT POWER 2 --

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-16

5.4.2 GTX 345/345D/345R/345DR (J3252)

5 4 3 2 1

10 9 8 7 6

15 14 13 12 11

Figure 5-8 Rear View, Connector J3252

Table 5-7 J3252 Pinout

Pin GTX 345/345R Pin Name I/O

1 ETHERNET OUT 1B OUT

2 ETHERNET IN 1B IN

3 ETHERNET OUT 2B OUT

4 ETHERNET IN 2B IN

5 RS-232 OUT 4 OUT

6 ETHERNET OUT 1A OUT

7 ETHERNET IN 1A IN

8 ETHERNET OUT 2A OUT

9 ETHERNET IN 2A IN

10 RS-232 IN 4 IN

11 RS-422 A OUT

12 RS-422 B OUT

13 CONFIGURABLE DISCRETE 11 IN/OUT

14 CONFIGURABLE DISCRETE 12 IN/OUT

15 RS-232 GND 4 --

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-17

5.4.3 Altitude Functions

Gillham code altitude inputs are considered active if either the voltage to ground is < 1.9 V or the
resistance to ground is < 375 . These inputs are considered inactive if the voltage to ground is
11-33 VDC. The GTX 3X5/3X5R discrete I/O pins are configurable. If the Gillham input is not enabled in
the configuration menu, then the Gillham code altitude pins can be used for other discrete input functions.
If the Gillham input is enabled, these pins will not be available for selection on other discrete inputs in the
configuration menu.

Table 5-8 GTX 3X5/3X5R Encoded Altitude Pin Assignments

Pin Name Pin Number I/O Connector

ALTITUDE D4 13 IN J3251

ALTITUDE A1 10 IN J3251

ALTITUDE A2 32 IN J3251

ALTITUDE A4 53 IN J3251

ALTITUDE B1 11 IN J3251

ALTITUDE B2 33 IN J3251

ALTITUDE B4 54 IN J3251

ALTITUDE C1 12 IN J3251

ALTITUDE C2 34 IN J3251

ALTITUDE C4 55 IN J3251

ALTITUDE COMMON 56 -- J3251

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-18

5.4.4 Discrete Functions

Discrete Outputs

Table 5-9 GTX 3X5/3X5R Discrete Outputs

Pin Name Pin Number I/O Unit Connector

TRANSPONDER FAIL #1 17 OUT All J3251

EXTERNAL SUPPRESSION 18 IN/OUT All J3251

REPLY ACTIVE X OUT All J3251/J3252

TRANSPONDER FAIL #2 X OUT All J3251/J3252

ALTITUDE ALERT* X OUT All J3251/J3252

EQUIPMENT STATUS X OUT All J3251/J3252

TRAFFIC ALERT X OUT

TRAFFIC STANDBY X OUT

TRAFFIC TEST X OUT

TCAD SENSITIVITY X OUT

ADS-B OUT FUNCTION FAIL X OUT All J3251/J3252

STANDBY ALERT X OUT All J3251/J3252

TRANSPONDER ACTIVE X OUT All J3251/J3252

DIVERSITY FAIL X OUT

* INACTIVE: 10 ≤ Vin ≤ 33 VDC or Rin ≥ 100 kΩ (Open)

ACTIVE: Vin ≤ 1.9 VDC with ≥75 uA sink current, or Rin ≤ 375 Ω (GND)

Sink current is internally limited to 200 uA max for a grounded input.

X Denotes that this discrete output can be configured to any available discrete output pin on either the
J3251 or J3252 connectors. Refer to table 5-10 for a list of configurable output pins.

345/345D/

345R/345DR

345/345D/

345R/345DR

345/345D/

345R/345DR

345/345D/

345R/345DR

335D/335DR/

345D/345DR

J3251/J3252

J3251

J3251

J3251/J3252

J3251/J3252

Table 5-10 GTX 3X5/3X5R Configurable Output Pins

Pin Name Pin Number I/O

TRANSPONDER FAIL #1 17 OUT All J3251

CONFIGURABLE DISCRETE #1 15 IN/OUT All J3251

CONFIGURABLE DISCRETE #2 16 IN/OUT All J3251

CONFIGURABLE DISCRETE #11 13 IN/OUT 345/345R J3252

CONFIGURABLE DISCRETE #12 14 IN/OUT 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-19

Discrete Inputs

Table 5-11 GTX 3X5/3X5R Discrete Inputs

Pin Name Pin Number I/O

TIS-A SELECT* X IN 335/335R J3251

ALTITUDE SOURCE* X IN All J3251/J3252

AUDIO MUTE X IN All J3251/J3252

AUDIO CANCEL 37 IN All J3251

TRAFFIC AUDIO MUTE X IN All J3251/J3252

TRAFFIC AUDIO CANCEL X IN All J3251/J3252

AIR DATA SOURCE* 58 IN All J3251

SQUAT 57 IN All J3251

IDENT* 36 IN All J3251

STANDBY* 14 IN All J3251

INSTALL ID SELECT 13 IN All J3251

EXTERNAL SUPPRESSION I/O 18 IN/OUT All J3251

* INACTIVE: 10 ≤ Vin ≤ 33 VDC or Rin ≥ 100 kΩ (Open)

ACTIVE: Vin ≤ 1.9 VDC with ≥75 uA sink current, or Rin ≤ 375 Ω (GND)

Sink current is internally limited to 200 uA max for a grounded input.

Unit (335/345/

335R/345R)

Connector

X Denotes that this discrete input can be configured to any available discrete input pin on either the
J3251 or J3252 connectors. Refer to table 5-12 for a list of configurable input pins.

Table 5-12 GTX 3X5/3X5R Configurable Input Pins

Pin Name Pin Number I/O

AUDIO INHIBIT #2 37 IN All J3251

AIR DATA SELECT 58 IN All J3251

SQUAT SWITCH 57 IN All J3251

EXTERNAL IDENT 36 IN All J3251

EXTERNAL STANDBY 14 IN All J3251

EXTERNAL SUPPRESSION I/O 18 IN/OUT All J3251

CONFIGURABLE DISCRETE #1 15 IN/OUT All J3251

CONFIGURABLE DISCRETE #2 16 IN/OUT All J3251

CONFIGURABLE DISCRETE #11 13 IN/OUT 345/345R J3252

CONFIGURABLE DISCRETE #12 14 IN/OUT 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-20

5.4.5 RS-232 Input/Output

Table 5-13 GTX 3X5/3X5R RS-232 Connections

Pin Name Pin Number I/O

RS-232 OUT 1 9 OUT All J3251

RS-232 IN 1 31 IN All J3251

RS-232 OUT 2 8 OUT All J3251

RS-232 IN 2 30 IN All J3251

RS-232 OUT 3 7 OUT All J3251

RS-232 IN 3 29 IN All J3251

RS-232 OUT 4 5 OUT 345/345R J3252

RS-232 IN 4 10 IN 345/345R J3252

Unit (335/345/

335R/345R)

Connector

5.4.6 ARINC 429 Input/Output

Table 5-14 GTX 3X5/3X5R ARINC 429 Connections

Pin Name Pin Number I/O

ARINC 429 IN 1A 27 IN All J3251

Unit (335/345/

335R/345R)

Connector

ARINC 429 IN 1B 28 IN All J3251

ARINC 429 OUT 1A 5 OUT All J3251

ARINC 429 OUT 1B 6 OUT All J3251

ARINC 429 IN 2A 48 IN All J3251

ARINC 429 IN 2B 49 IN All J3251

5.4.7 RS-422 Out

Table 5-15 GTX 345/345R RS-422 Connections

Pin Name Pin Number I/O

RS-422 A 11 OUT 345/345R J3252

RS-422 B 12 OUT 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-21

5.4.8 HSDB Input/Output

Table 5-16 GTX 345/345R HSDB Connections

Pin Name Pin Number I/O

ETHERNET OUT 1A 6 OUT 345/345R J3252

ETHERNET IN 1A 7 IN 345/345R J3252

ETHERNET OUT 1B 1 OUT 345/345R J3252

ETHERNET IN 1B 2 IN 345/345R J3252

ETHERNET OUT 2A 8 OUT 345/345R J3252

ETHERNET IN 2A 9 IN 345/345R J3252

ETHERNET OUT 2B 3 OUT 345/345R J3252

ETHERNET IN 2B 4 IN 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 5-22

6 UNIT REMOVAL AND RE-INSTALLATION

6.1 GTX 330/330D .................................................................................................................................6-2

6.2 GTX 33/33D .....................................................................................................................................6-4

6.3 GTX 3X5 ..........................................................................................................................................6-5

6.3.1 GTX 335/335D/345/345D Panel Mounted Units.....................................................................6-11

6.3.2 GTX 3X5R/3X5DR with Standard or GX000 System Rack Mount .......................................6-13

6.3.3 GTX 3X5R/3X5DR with Vertical Mount ................................................................................6-15

6.3.4 Garmin Altitude Encoder .........................................................................................................6-17

6.4 Transponder Antenna......................................................................................................................6-19

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-1

6.1 GTX 330/330D

WARNING

CAUTION

NOTE

Ensure that the aircraft power is off before removal or reinstallation of the GTX 330/330D.
Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and re-installation of equipment installed
under STC SA01714WI. After removal and reinstallation, the GTX 330/330D return to service procedures
must be performed in accordance with Section 9.

Removal

1. Insert the hex drive tool into the access hole at the bottom of the unit face and turn
counterclockwise until the unit is forced out about 3/8 inch.

2. Pull the unit straight out of the rack.

Re-installation

Do not over-tighten the unit in the rack. Torque exceeding 15 in-lbs can damage the
locking mechanism.

It may be necessary to insert the hex drive tool into the access hole and turn the cam
mechanism 90° counterclockwise to ensure correct position prior to placing the unit in the
rack.

1. Slide the GTX 330/330D straight in the rack until it stops, about one inch short of the final
position.

2. Insert a 3/32-inch hex drive tool into the access hole at the bottom of the unit face.

3. Turn the hex tool clockwise while pressing on the left side of the bezel until the unit is firmly
seated in the rack.

4. Count the number of complete revolutions the hex screw can be turned until it cannot turn any
more. Take care not to over-tighten. Three turns is the minimum for proper installation. If fewer
than three turns are possible, ensure nothing obstructs the unit from fully seating in the rack. The
mounting rack may need to be moved aft (toward the pilot) so that the aircraft panel does not
obstruct the unit from properly engaging in the rack.

5. Complete the appropriate return to service procedures in Section 9.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-2

Figure 6-1 GTX 330 Mounting Rack/Connector Assembly

211-60234-08

(2 PLACES)

115-00294-00

330-00053-01 (BNC)

OR

330-00053-02 (TNC)

(1 OR 2 PLACES)

211-63234-12

(2 PLACES)

NUT SUPPLIED

WITH 330-00053-XX

212-00022-00

(1 OR 2 PLACES)

125-00002-00

125-00056-00

211-60234-12

(2 PLACES)

330-00185-62

CONTAINS

336-00021-00

330-00220-37

330-00228-20

CONTAINS

336-00029-00

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-3

6.2 GTX 33/33D

WARNING

115-00629-00

125-00002-00

011-00950-03

211-63234-11

(2 PLACES)

211-60234-08

(2 PLACES)

330-00053-01 (BNC)

OR

330-00053-02 (TNC)

(1 OR 2 PLACES)

212-00022-00

(1 OR 2 PLACES)

NUT SUPPLIED

WITH 330-00053-XX

330-00185-62

011-01169-01

Ensure that the aircraft power is off before removal or re-installation of the GTX 33/33D.
Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and installation of equipment installed
under STC SA01714WI. After removal and re-installation, the GTX 33/33D return to service procedures
must be performed in accordance with Section 9.

Removal

1. Gain access to the transponder.

2. Unlock the GTX 33/33D handle by loosening the Phillips screw on the handle.

3. Pull the handle upward to unlock the GTX 33/33D. Gently remove the unit from the rack.

Re-installation

1. Visually inspect the connectors to verify there are not bent or damaged pins. Repair any damage.

2. Gently insert the GTX 33/33D into its rack. The handle should engage the locking mechanism
used to secure the unit in place.

3. Press down on the GTX 33/33D handle to lock the unit into the rack.

4. Lock the handle to the GTX 33/33D body by tightening the Phillips head screw.

Figure 6-2 GTX 33 Mounting Rack/Connector Assembly

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-4

6.3 GTX 3X5

GTX 3X5

P3251

GTX 345'/

345R'5 Only

This section contains parts, procedures, and requirements for assembly, removal, and re-installation of
GTX 3X5 equipment installed under STC SA01714WI. After removal and re-installation, the GTX 3X5
return to service procedures must be performed in accordance with Section 9.

Table 6-1 GTX 3X5 Connector Kit Hardware

Description P/N Qty

Connector, hi-dense, D-sub, mil crimp 62 ckt 330-00185-62 1

Sub-assembly, backshell with hardware, 37/62 pin 011-00950-03 1

Sub-assembly, ground adapter, shell 4&5 011-01169-01 1

Screw, 4-40 x .250, FLHP 100, SS/P, nylon 211-63234-06 2 ea connector

Connector, hi-dense, D-sub, mil crimp, 15 ckt 330-00185-15 1

Sub-assembly, backshell with hardware, 9/15 pin 011-00950-00 1

Sub-assembly, ground adapter, shell 1-3 011-01169-00 1

Figure 6-3 GTX 3X5 Connector Kits

Refer to Table 6-2 for the list of backplate items for the standard/G1000 mounting assembly. Refer to
Figure 6-4 and Figure 6-5 for the backplate assembly.

Table 6-2 Standard/G1000 Mount Back Plate Hardware

Item Description P/N Qty

1 DCP, connector plate, GTX 3X5, w/secondaries 125-00307-10 1

2 Connector, male/female special, BNC 330-00053-01 1

3 Washer, shoulder, GNC 400 212-00022-00 2

4 Connector, male/female, special, BNC/TNC 330-00053-02 1

5 Screw, 4-40 X .250, PHP, SS/P, nylon 211-60234-08 4

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-5

Figure 6-4 GTX 3X5 without GPS Back Plate Assembly (P/N 011-02976-00)

3

1

2

NUT SUPPLIED

WITH ITEM 2

5
4

1

2

4

3
2

NUTS SUPPLIED
WITH ITEMS 2 & 4

5
4

Figure 6-5 GTX 3X5 with GPS Back Plate Assembly (P/N 011-02976-01)

Refer to Table 6-3 for the list of backplate items for the vertical mounting assembly. Refer to Figure 6-6,
Figure 6-7, and Figure 6-8 for the backplate assemblies.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-6

Table 6-3 Vertical Mount Back Plate Hardware

1

2

7

NUT SUPPLIED
WITH ITEM 2

8
2

9
2

Item Description P/N Qty

1 DCP, connector plate, remote, GTX 3X5, w/secondaries 125-00343-10 1

2 Connector, male/female special, BNC 330-00053-01 1

3 Washer, shoulder, GNC 400 212-00022-00 2

4 Connector, male/female, special, BNC/TNC 330-00053-02 1

7 Washer, centering, no float 212-00022-10 1

8 Washer, split lock, size 8 212-00018-04 2

9 Screw, captive, 8-32, .62", 3/832 hex drv 211-00290-00 2

Figure 6-6 GTX 3X5 Vertical Mount without GPS, Back Plate Assembly (P/N 011-02976-10)

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-7

Figure 6-7 GTX 3X5 Vertical Mount with GPS, Back Plate Assembly

2

1

7

3

4

NUTS SUPPLIED
WITH ITEMS 2 & 4

8
2

9
2

4

1

7

NUT SUPPLIED
WITH ITEM 4

9
2

8
2

(P/N 011-02976-11)

Figure 6-8 GTX 3X5 Vertical Mount with TNC XPDR Back Plate Assembly

(P/N 011-02976-12)

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-8

Refer to Table 6-4 for the list of backplate items for the standard/G1000 mounting assembly for the

2

5

4 1

3

NUTS SUPPLIED

WITH ITEMS 2 & 4

GTX 3X5D, and refer to Figure 6-9 for the backplate assembly. Refer to Table 6-5 for the list of backplate
items for the vertical mounting assembly for the GTX 3X5D, and refer to Figure 6-10 for the backplate
assembly.

Table 6-4 Standard and G1000 Mount Backplate Hardware

Item Description P/N QTY

1 DCP, connector plate, GTX 3X5D, with secondaries 125-00473-01 1

2 Conn, male/female special BNC 330-00053-01 2

3 Washer, shoulder, GNC400 212-00022-00 3

4 Conn, M/F, special BNC/RP-SMA 330-00053-08 1

5 Screw, 4-40 x 0.250, PHP, SS/P, w/ nylon 211-60234-08 4

Figure 6-9 GTX 3X5D with Backplate Assembly (P/N 011-04340-02)

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-9

Table 6-5 Vertical Mount Backplate Hardware

5

3

4

1

2

6

NUTS SUPPLIED

WITH ITEMS 2&4

Item Description P/N QTY

1 DCP, connector plate, vert, GTX 3X5DR, with secondaries 125-00474-01 1

2 Conn, male/female special BNC 330-00053-01 2

3 Washer, shoulder, GNC400 212-00022-00 3

4 Conn, M/F, special BNC/RP-SMA 330-00053-08 1

5 Screw, captive, 8-32, 0.62”, 3/32 hex drive 211-00290-00 2

6 Washer, split lock, size 8 212-00018-04 2

Figure 6-10 GTX 3X5DR with Backplate Assembly (P/N 011-04340-10)

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-10

6.3.1 GTX 335/335D/345/345D Panel Mounted Units

WARNING

CAUTION

NOTE

Ensure that the aircraft power is off before removal or re-installation of the GTX 3X5.
Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and re-installation of the GTX 335/335D/
345/345D panel-mounted units installed under STC SA01714WI. After removal and re-installation, the
GTX 335/335D/345/345D return to service procedures must be performed in accordance with Section 9.

Removal

1. Insert the hex drive tool into the access hole on the unit face and rotate counterclockwise until the
unit is forced out about 3/8 inch.

2. Pull the unit straight out of the rack.

Re-installation

Be sure not to over-tighten the unit into the rack. Torque exceeding 8 in-lbs can damage

the locking mechanism.

It may be necessary to insert the hex drive tool into the access hole and rotate the cam
mechanism 90° counterclockwise to ensure correct position prior to placing the unit in the
rack.

1. Slide the GTX 3X5 straight in the rack until it stops, about one inch short of the final position.

2. Insert a 3/32-inch hex drive tool into the access hole at the bottom of the unit face.

3. Turn the hex tool clockwise while pressing on the left side of the bezel until the unit is firmly
seated in the rack.

4. Count the number of complete revolutions the hex screw can be turned until it cannot turn any
more. Be careful not to over-tighten. Three turns is the minimum for proper installation. If fewer
than three turns are possible, ensure nothing obstructs the unit from fully seating in the rack. The
mounting rack may need to be moved aft (toward the pilot) so that the aircraft panel does not
obstruct the unit from properly engaging in the rack.

5. Complete the applicable return to service procedures in Section 9.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-11

Figure 6-11 GTX 3X5 Mounting Rack/Connector Assembly

81,7

5$&.

%$&.3/$7(

81,7
,167$//5$&.
%$&.3/$7($66(0%/<
&211(&725.,7
&21),*02'8/(

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-12

6.3.2 GTX 3X5R/3X5DR with Standard or GX000 System Rack Mount

WARNING

CAUTION

NOTE

Ensure that the aircraft power is off before removal or re-installation of the GTX 3X5R.
Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and installation of GTX 335R/335DR/
345R/345DR equipment installed using a standard remote mount or GX000 system rack mount. After
removal and re-installation, the GTX 335R/335DR/345R/345DR return to service procedures must be
performed in accordance with Section 9.

Removal

1. Gain access to the transponder.

2. Insert the hex drive tool into the access hole on the unit face and rotate counterclockwise until the
unit is forced out about 3/8 inch.

3. Grab the pull-tab on the front of the unit and pull the unit straight out of the rack.

Re-installation

Be sure not to over-tighten the unit into the rack. Torque exceeding 8 in-lbs can damage

the locking mechanism.

It may be necessary to insert the hex drive tool into the access hole and rotate the cam
mechanism 90° counterclockwise to ensure correct position prior to placing the unit in the
rack.

1. Visually inspect the connectors and pins to ensure they are not bent or damaged. Repair any
damage.

2. Slide the GTX 3X5 straight in the rack until it stops, about one inch short of the final position.

3. Insert a 3/32-inch hex drive tool into the access hole at the bottom of the unit face.

4. Turn the hex tool clockwise while pressing on the left side of the bezel until the unit is firmly
seated in the rack.

5. Count the number of complete revolutions the hex screw can be turned until it cannot turn any
more. Be careful not to over-tighten. Three turns is the minimum for proper installation. If fewer
than three turns are possible, ensure nothing obstructs the unit from fully seating in the rack.

6. Complete the applicable return to service procedures in Section 9.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-13

Figure 6-12 GTX 3X5R Standard Mounting Rack/Connector Assembly

81,7

5$&.

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81,7
,167$//5$&.
%$&.3/$7($66(0%/<
&211(&725.,7
&21),*02'8/(

81,7
,167$//5$&.
1873/$7(.,7*3261276+2:1
%$&.3/$7($66(0%/<
&211(&725.,7
&21),*02'8/(

Figure 6-13 GTX 3X5R G1000 Mounting Rack/Connector Assembly

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-14

6.3.3 GTX 3X5R/3X5DR with Vertical Mount

CAUTION

Before removal or re-installation of the GTX 3X5R, ensure the aircraft power is off.
Unplug any auxiliary power supply.

This section contains procedures for removal and installation of the GTX 335R/335DR/345R/345DR
equipment installed using a vertical mount. After removal and re-installation, the GTX 335R/335DR/
345R/345DR return to service procedures must be performed.

Removal

1. Gain access to the transponder.

2. Remove the two captive screws securing the back plate to the transponder body using a 3/32" hex
tool.

3. Carefully remove the back plate and connector assembly from the unit.

4. While pulling, turn the large knob at the base of the unit counterclockwise until it can be pulled off
the tab at the base of the unit.

5. Slide the unit forward and up until it clears the base plate.

Installation

1. Tilt the unit so that the toe of the GTX 3X5 shoe fully engages the base plate.

2. Ensure that the unit is fully engaged and in line with the base.

3. Lift the large knob on the install rack up and over the round protrusion on the base plate.

4. Turn the large knob clockwise until the unit is secure.

5. Carefully install the back plate onto the unit.

6. Secure with the two captive screws using a 3/32" hex tool.

7. Complete the applicable return to service procedures.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-15

Figure 6-14 GTX 3X5R Vertical Mounting Rack/Connector Assembly

UNIT: 011-03303-40
INSTALL RACK: 011-03762-00
BACK PLATE ASSEMBLY: 011-02976-11
CONNECTOR KIT: 011-02977-01
CONFIG MODULE: 011-00979-03

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-16

6.3.4 Garmin Altitude Encoder

WARNING

Ensure that the aircraft power is off before removal or re-installation of the GTX 3X5.
Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and installation of the Garmin altitude
encoder equipment installed under STC SA01714WI. After removal and re-installation, the
GTX 3X5 return to service procedures must be performed in accordance with Section 9.

Removal

1. Remove the transponder. Refer to Section 6.3 for details.

2. Remove the static line attached to the altitude encoder.

3. Disconnect wiring harness at the altitude encoder.

4. Remove two screws securing the unit to the back plate.

Re-installation

1. Secure altitude encoder to back plate assembly with two screws, torque to 8 in-lbs.

2. Connect wiring harness to altitude encoder.

3. Secure the static line to the altitude encoder using standard practices.

4. Install transponder. Refer to Section 6.3 for details.

5. Complete the applicable return to service procedures in Section 9.

6. Complete the static system and transponder checks described in Section 4.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-17

Table 6-6 Garmin Altitude Encoder Kit - P/N 011-03080-00

GARMIN
ALTITUDE
ENCODER

Description P/N Qty

Sub-assembly, altitude encoder, unit only 011-03080-01 1

Screw, 4-40 x .250, PHP, SS/P, w/nyl 211-60234-08 2

Screw, 4-40 x .312, FLHP 100, SS/P, nyl 211-63234-09 2

Harness, 4 cond, Garmin altitude encoder 325-00421-00 1

Figure 6-15 Garmin Altitude Encoder with Back Plate Assembly

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-18

6.4 Transponder Antenna

The transponder antenna(s) are not installed by this STC. Refer to the antenna manufacturer's maintenance
information for removal and re-installation instructions.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 6-19

7SOFTWARE

7.1 Software Check.................................................................................................................................7-2

7.2 GTX 33/330 Software Update ..........................................................................................................7-5

7.2.1 Download Procedures ................................................................................................................7-5

7.2.2 GTX 33/330 Software Loading ..................................................................................................7-6

7.3 GTX 3X5 Software Update ..............................................................................................................7-7

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 7-1

7.1 Software Check

NOTE

NOTE

If software is loaded during maintenance, conduct a final software review.

It is essential that the software version is correct. Earlier GTX 33X software versions are
non-compliant with ADS-B Out Version 2 requirements. If the software version and/or part
number does not match those specified, or if the software is not successfully loaded,

DO NOT continue. Troubleshoot and resolve the issue before continuing.

Screen shots in this section are provided for reference only. For approved GTX software
versions, refer to GTX 33X and GTX 3X5 ADS-B AML STC Equipment List.

GTX 330/330D Software Version Check

1. Start the GTX 330/330D in normal mode.

2. Observe the start up screen. Refer to Figure 7-1 for details.

Figure 7-1 GTX 330 Start-Up Screen

3. Press either the 8 key or the 9 key until you see the SYS software version screen.

4. Verify the version number matches the approved version listed in the Equipment List. Refer to
Figure 7-2 for details.

Figure 7-2 GTX 330 Product Data Page

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 7-2

GTX 3X5 Software Version Check

NOTE

1. Start the GTX 3X5 in normal mode.

2. Observe the start-up screen until you see “PRESS ENT FOR PRODUCT DATA.” Refer to Figure
7-3 for details.

Figure 7-3 GTX 3X5 Start-Up Screen

3. Press the ENT key to navigate to the software version screen.

4. Verify the version number matches the approved version listed in the Equipment List. Refer to
Figure 7-4 for details.

Figure 7-4 GTX 3X5 Product Data Page

GTX 33/33D/3X5R Software Version Check (GTN 6XX/7XX)

The following procedures provide an overview to verify the software version of the
GTX 33/33D/3X5R when interfaced with the GTN 6XX/7XX. Refer to GTN 6XX/7XX Part
23 AML STC Installation Manual for additional details.

1. On the GTN 6XX/7XX System Page, touch the External LRUs key.

2. Observe the reported GTX software version number. Refer to Figure 7-5 for details.

3. Verify the version number matches the approved version listed in the Equipment List.

Figure 7-5 GTN 6XX/7XX System Page

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
Rev. 7 Page 7-3

GTX 3X5R Software Version Check (GX000)

NOTE

The following procedures provide an overview to verify the software version of the
GTX 3X5R when interfaced with the GX000. Refer to the applicable G1000 Series Pilot
Guides or Installation Manual for additional details.

1. On the GX000 PFD enter the configuration option.

2. On the System Status page, scroll to the GTX LRU.

3. Observe the reported GTX software version number. Refer to Figure 7-6 for details.

4. Verify the version number matches the approved version listed in the Equipment List.

Figure 7-6 GX000 System Status Page

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7.2 GTX 33/330 Software Update

P3301

GARMIN GTX 330/33

AIRCRAFT POWER 21
AIRCRAFT POWER 42

TEST M OD E SELEC T 18

GROUND 27
GROUND 43

#1 RS-232 IN 2 2

OUT 23

NO

NC

TEST MODE SELECT

TRANSPONDER

14/28 VDC AIRCRAFT POWER

5A

1
5

3
2

TEST MODE SELECT S WITCH
OPTIONAL FOR GTX 330

3
2

9-PIN D-SUB CONNECTOR TO
PC’S COMM PORT

If a unit is replaced and does not have the approved version of software installed, software can be
downloaded from the Dealer Resource Center at www.flyGarmin.com
software loading procedures below must be carried out on each GTX.

The GTX 330 software can be updated in Configuration mode as well as in Test mode. Updating software
in Configuration mode does not require the TEST MODE SELECT switch. However, the TEST MODE
SELECT switch is required for the GTX 33 series. Refer to Figure 7-7 for software update connections.

Figure 7-7 Software Update Connection

. For dual GTX installations the

7.2.1 Download Procedures

1. Access the

2. Obtain the transponder software as specified in the Equipment List and download to a laptop
computer.

3. Access the target directory for the software on the laptop computer.

4. Extract the files by double clicking on the downloaded .exe file.

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Dealer Resource Center on Garmin’s website.

7.2.2 GTX 33/330 Software Loading

CAUTION

NOTE

If the unit is removed from the aircraft and operated, connect J3302
(GTX 33/330/33D/330D) and J3303 (GTX 330D/33D) to a 50 Ω 5 watt load. The GTX
transmits Mode S acquisition squitter pulses once per second whether interrogations are
received or not. Failure to connect a dummy load or antenna during this procedure will
cause the transponder to fail and possibly damage the unit.

1. Remove power from the GTX.

2. Connect the test harness to the GTX and laptop. Refer to Figure 7-7 for details.

3. Enable the TEST MODE switch on the test harness.

4. Power on the GTX.

5. Double click on the file UPLOADXX.BAT (XX is an incremental number assigned to a specific
software version). The program will begin communicating with the GTX.

6. The upload process could take up to six minutes to complete.

GTX 330 units will show a dynamic display test screen.

7. Once the upload is completed, the unit will reset itself, and turn on.

8. Remove power from the GTX.

9. Remove the test harness between the laptop and the GTX.

10. Install GTX into aircraft and power up system.

11. Verify the software version is correctly displayed.

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7.3 GTX 3X5 Software Update

CAUTION

If the unit is removed from the aircraft and operated, connect the transponder antenna
connection to a 50 Ω 5 watt load. The GTX transmits Mode S acquisition squitter pulses
once per second whether interrogations are received or not. Failure to connect a dummy
load or antenna during this procedure will cause the transponder to fail and possibly
damage the unit.

If a unit is replaced and does not have the approved version of software installed, software can be
downloaded from the Dealer Resource Center at www.flyGarmin.com
software loading procedures below must be carried out on each GTX.

For more information on downloading, installing, and utilizing the GTX 3X5 installation tool download
the GTX 3X5 Install Tool Manual (P/N: 190-01499-30) from the Dealer Resource Center

Software may be loaded by performing the following steps on the Software Upload page.

1. Download the latest GTX 3X5 software from the Garmin Dealer Resource Center

2. Under “Step 1 - Select a File,” select the Browse key and locate the Boot Block software file
containing the GTX 3X5 software previously downloaded.

3. Under “Step 2 - Upload Options,” select the options to be updated.

4. Select the Upload key.

5. Wait for upload to complete. Individual files will be marked as complete as they are installed.

6. Under “Step 1 - Select a File,” select the Browse key and locate the Main System software file
containing the GTX 3X5 software previously downloaded.

7. Under “Step 2 - Upload Options,” select the remaining options to be updated.

8. Wait for upload to complete. Individual files will be marked as complete as they are installed.

9. After successful completion, verify the correct software versions and part numbers display on the
Transponder page under the Product Data group.

. For dual GTX installations the

.

.

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Figure 7-8 GTX 3X5 Install Tool Software Upload Page

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8 SYSTEM CONFIGURATION AND CHECKOUT

8.1 Overview...........................................................................................................................................8-2

8.2 System Checkout ..............................................................................................................................8-2

8.3 GTX 33/330 Configuration...............................................................................................................8-3

8.3.1 GTX 330/330D Configuration ...................................................................................................8-3

8.3.2 GTX 33/33D Configuration (GTN 6XX/7XX)..........................................................................8-3

8.3.3 GTX 33/33D Configuration (GNS 480).....................................................................................8-3

8.4 GTX 3X5 Configuration...................................................................................................................8-4

8.4.1 GTX 3X5/3X5D Configuration .................................................................................................8-4

8.4.2 GTX 3X5R/3X5DR Configuration (GTN 6XX/7XX, GNS 480, or G1000) ............................8-4

8.5 GTX Airborne Test Mode.................................................................................................................8-5

8.5.1 GTX 33/330 Airborne Mode (v8.02 or higher).........................................................................8-5

8.5.2 GTX 3X5 Airborne Mode ..........................................................................................................8-6

8.6 Regulatory Test.................................................................................................................................8-7

8.7 ADS-B Out Test................................................................................................................................8-8

8.8 GTX 3X5 with TCAS System Test (GX000 Only)..........................................................................8-9

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8.1 Overview

This section contains instructions for configuring the GTX as well as checks to ensure the system is
properly installed and functioning correctly. The steps that are not applicable to a particular installation
may be skipped.

8.2 System Checkout

Original GTX is Reinstalled

If the original GTX is reinstalled, configuration and software loading are not required. Continue to
GTX Test (Section 8.5).

New, Repaired, or Exchanged GTX is Installed

If a new, repaired, or exchanged GTX is installed, the AML approved software (refer to Section 7.2 or
Section 7.3) and the configuration files from the Post Install Checkout Log in the aircraft permanent
records (refer to Section 8.3) must be loaded to the unit.

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8.3 GTX 33/330 Configuration

NOTE

Retrieve the Post Installation Checkout Log from the aircraft permanent records. For the maintenance
activities that repaired or replaced the previous GTX, configure the GTX as defined by the data contained
in the Post Installation Checkout Log.

Ensure the Post Installation Checkout Log remains with the aircraft permanent records
upon completion of any maintenance activities.

8.3.1 GTX 330/330D Configuration

Hold down the FUNC key and press the ON key to access the configuration pages. The FUNC key
sequences forward through the configuration pages. The START/STOP key reverses through the pages,
stopping at the Menu page. The CRSR key highlights selectable fields on each page. When a field is
highlighted, the 0 – 9 keys enter numeric data and the 8 or 9 keys move through list selections. Press the
CRSR key to accept changes. When a field is highlighted, pressing the FUNC key moves to the next
configuration page without saving the changes.

Changes made through the configuration pages are stored in EEPROM memory. To exit the configuration
pages, turn the power off. Then turn on again (without holding the FUNC key) for normal operation.

8.3.2 GTX 33/33D Configuration (GTN 6XX/7XX)

For GTX 33/33D installations interfacing to a GTN 6XX/7XX, configuration of the GTX is accomplished
through the GTN 6XX/7XX. Access the Interfaced Equipment page by touching the Interfaced
Equipment key on the GTN Setup page. Next, go to the External Systems page and touch the
corresponding key for the transponder to be configured, XPDR1 or XPDR2 (if present). This key displays
a page which allows the remote transponder to be configured.

8.3.3 GTX 33/33D Configuration (GNS 480)

For GTX 33/33D installations interfacing to a GNS 480, configuration of the GTX is accomplished
through the GNS 480. Access the GTX configuration page from the GND Maintenance mode display of
the GNS 480. This page will allow the remote transponder to be configured. Refer to the Equipment Setup
and Configuration section of GNS 480 (CNX80) Color GPS/NAV/COM Installation Manual for detailed
instructions.

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8.4 GTX 3X5 Configuration

Retrieve the Post Installation Checkout log from the aircraft permanent records. For the maintenance
activities that repaired or replaced the previous GTX, configure the GTX as defined by the data contained
in the Post Installation Checkout Log.

8.4.1 GTX 3X5/3X5D Configuration

Hold down the ENT key and press the ON key to access the configuration pages. The FUNC key
sequences forward through the configuration pages. The CLR key reverses through the pages. The 8 or 9
key scrolls up or down through the items on each configuration page. The CRSR key highlights selectable
fields on each page. When a field is highlighted, the 0 – 9 keys enter numeric data and the 8 or 9 keys move
through list selections. Press the ENT key to accept changes. When a field is highlighted, pressing the
FUNC key moves to the next configuration page without saving the changes.

Changes made through the configuration pages are stored in EEPROM memory. To exit the configuration
pages, reset the system power for normal mode.

8.4.2 GTX 3X5R/3X5DR Configuration (GTN 6XX/7XX, GNS 480, or G1000)

For GTX 3X5R installations interfacing to a GTN 6XX/7XX, GNS 480, or G1000 system, configuration
of the GTX is accomplished through the GTX Installation Tool. Refer to GTX 3X5/3X5R Software Update
(Section 7.3) for instructions on downloading, installing, and connecting the installation tool to the
GTX 3X5/3X5R unit.

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