Garmin GTX 330D, GTX 330, GTX 335, GTX 345, GTX 335R Maintenance 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 December 2017 Revision 6

© 2013-2017 Garmin International or its subsidiaries

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

RECORD OF REVISIONS

Revision

6 12//17

5 10/05/16

4 07/21/16 Added GTX 3X5 vertical mount.

3 03/03/16 Added GTX 3X5 products.

2 09/18/14 Minor edits. Refer to Current Revision Description for details.

1 05/01/13 Initial release.

Revision

Date

Description

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

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

CURRENT REVISION DESCRIPTION

Section Page Description

3.1 3-2 Removed directions for software v7.01 or earlier

5.1 5-2 Replaced Figure 5-1 with improved troubleshooting flowchart

5.2 5-3 Replaced Figure 5-4 Sheets 1-5 with improved troubleshooting flowcharts.

5.2 5-9 Removed Figure 5-5 Sheet 1-5. Alert messages and faults are covered by Figure 5-4.

B.1 B-2

Added Diamond DA 62, Tecnum P2010, Ruschmeyer R90-230RG, and Slingsby
T67M260 to Table B-1.

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

INFORMATION SUBJECT TO EXPORT CONTROL LAWS

WARNING

WARNING

CAUTION

WARNING

CAUTION

NOTE

This document may contain information which is subject to the Export Administration Regulations (EAR)
issued by the United States Department of Commerce (15 CFR, Chapter VII, Subchapter C) and which
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

Warni ngs 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. 6 Page iii

TABLE OF CONTENTS

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

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

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

1.3 Applicability...............................................................................................................................1-2

1.4 Publications ................................................................................................................................1-2

1.5 Revision and Distribution...........................................................................................................1-2

1.6 Reference....................................................................................................................................1-3

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

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

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

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

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

2.5 GTX 335R/345R 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 335/345..............................................................................................................................3-5

3.3 GTX 33/33D and GTX 335R/345R ...........................................................................................3-8

3.4 GTX 335R/345R with Legacy G1000 .......................................................................................3-9

3.5 GTX 3X5 Install Tool ..............................................................................................................3-12

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

4.1 Applicability...............................................................................................................................4-1

4.2 Airworthiness Limitations..........................................................................................................4-1

4.3 Servicing Information ................................................................................................................4-2

4.4 Maintenance Intervals ................................................................................................................4-3

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

4.6 Electrical Bonding Test..............................................................................................................4-6

4.7 Additional Instructions...............................................................................................................4-6

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

5.1 GTX General Troubleshooting...................................................................................................5-1

5.2 GTX Failure Annunciations .......................................................................................................5-3

5.3 GTX 33X Connector Pinout Information.................................................................................5-14

5.4 GTX 3X5 Connector Pinout Information.................................................................................5-19

6 UNIT REMOVAL AND REINSTALLATION...............................................................................6-1

6.1 GTX 330/330D...........................................................................................................................6-1

6.2 GTX 33/33D...............................................................................................................................6-3

6.3 GTX 3X5....................................................................................................................................6-4

6.4 Transponder Antenna ...............................................................................................................6-15

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

7.1 Software Check ..........................................................................................................................7-1

7.2 GTX 33/330 Software Update....................................................................................................7-6

7.3 GTX 3X5/3X5R Software Update .............................................................................................7-8

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

8.1 Overview ....................................................................................................................................8-1

8.2 System Checkout........................................................................................................................8-1

8.3 GTX 33/330 Configuration ........................................................................................................8-1

8.4 GTX 3X5 Configuration ............................................................................................................8-2

8.5 GTX Airborne Test Mode ..........................................................................................................8-4

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8.6 Regulatory Test ..........................................................................................................................8-6

8.7 ADS-B Out Test .........................................................................................................................8-7

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

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-1

B.2 Preparation of Aluminum Surfaces ...........................................................................................B-4

B.3 Composite Aircraft....................................................................................................................B-4

B.4 Tube and Fabric Aircraft ........................................................................................................... B-9

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 or GTX 335R Interface Summary ........................................................................2-7

Figure 2-4 GTX 345 or GTX 345R Interface Summary ........................................................................2-9

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

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

Figure 3-2 GTX 335/345 Front Panel ....................................................................................................3-5

Figure 3-3 GTN 7XX Transponder Control ...........................................................................................3-8

Figure 3-4 GTN 6XX Transponder Control ...........................................................................................3-8

Figure 3-5 GNS 480 Transponder Control .............................................................................................3-9

Figure 3-6 G1000 Transponder Control ...............................................................................................3-10

Figure 3-7 G1000 Transponder Control ...............................................................................................3-11

Figure 3-8 USB A and USB B Connectors ..........................................................................................3-12

Figure 3-9 GTX 3X5/3X5R State Page ................................................................................................3-13

Figure 3-10 GTX 3X5/3X5R Status Page ..............................................................................................3-14

Figure 3-11 GTX 3X5/3X5R Configuration Group ...............................................................................3-15

Figure 3-12 GTX 3X5/3X5R Diagnostics Group ..................................................................................3-17

Figure 3-13 GTX 3X5/3X5R Product Data Group ................................................................................3-18

Figure 5-1 GTX (All Models) Transponder Troubleshooting ................................................................5-2

Figure 5-2 GTX 330/330D Transponder Failure/Fault Messages ..........................................................5-3

Figure 5-3 GTX 33/33D Transponder Failure/Fault Messages ..............................................................5-4

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

Figure 5-5 GTX 3X5 Install Tool Failure/Fault MessagesTransponder Alerts .....................................5-9

Figure 5-6 Rear View, Connector P3301 .............................................................................................5-14

Figure 5-7 GTX 33/330 ARINC 429 Connections ...............................................................................5-18

Figure 5-8 Rear View, Connector J3251 ..............................................................................................5-19

Figure 5-9 Rear View, Connector J3252 ..............................................................................................5-21

Figure 6-1 GTX 330 Mounting Rack/Connector Assembly ..................................................................6-2

Figure 6-2 GTX 33 Mounting Rack/Connector Assembly ....................................................................6-3

Figure 6-3 GTX 3X5 Connector Kits .....................................................................................................6-4

Figure 6-4 GTX 3X5 without GPS Back Plate Assembly (P/N 011-02976-00) ....................................6-5

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

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

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

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

(P/N 011-02976-12) ...................................................................................................................................6-7

Figure 6-9 GTX 3X5 Mounting Rack/Connector Assembly .................................................................6-9

Figure 6-10 GTX 3X5R Standard Mounting Rack/Connector Assembly ..............................................6-11

Figure 6-11 GTX 3X5R G1000 Mounting Rack/Connector Assembly .................................................6-11

Figure 6-12 GTX 3X5R Vertical Mounting Rack/Connector Assembly ...............................................6-13

Figure 6-13 Garmin Altitude Encoder with Back Plate Assembly ........................................................6-15

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

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 ...........................................................................................

Figure 7-5 GTN 6XX/7XX System Page ...............................................................................................7-4

Figure 7-6 GX000 System Status Page ..................................................................................................7-5

Figure 7-7 Software Update Connection ................................................................................................7-6

....7-3

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 ......................................................................7-9

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

Figure B-2 Electrical Bonding Preparation – Bolt/Nut Joint ................................................................. B-1

Figure B-3 Electrical Bond Preparation – Terminal Lug .......................................................................B-1

Figure B-4 Fiberglass Insulation for Carbon Material ...........................................................................B-5

Figure B-5 Aluminum Tape Joint .......................................................................................................... B-6

Figure B-6 Aluminum Tape Ground Termination .................................................................................B-7

Figure B-7 Remote GTX Aluminum Tape Installation ......................................................................... B-8

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 ....................................................................................................1-2

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

Table 4-1 Maintenance Intervals ...........................................................................................................4-3

Table 5-1 GTX 33X Pinout .................................................................................................................5-14

Table 5-2 GTX 33X Encoded Altitude Pin Assignments ...................................................................5-16

Table 5-3 GTX 33/330 Discrete Outputs ............................................................................................5-17

Table 5-4 GTX 33/330 Discrete Inputs ...............................................................................................5-17

Table 5-5 GTX 33/330 RS-232 Connections ......................................................................................5-17

Table 5-6 J3251 Pinout .......................................................................................................................5-19

Table 5-7 J3252 Pinout .......................................................................................................................5-21

Table 5-8 GTX 3X5/3X5R Encoded Altitude Pin Assignments ........................................................5-22

Table 5-9 GTX 3X5/3X5R Discrete Outputs ......................................................................................5-23

Table 5-10 GTX 3X5/3X5R Configurable Output Pins .......................................................................5-24

Table 5-11 GTX 3X5/3X5R Discrete Inputs ........................................................................................5-25

Table 5-12 GTX 3X5/3X5R Configurable Input Pins ..........................................................................5-26

Table 5-13 GTX 3X5/3X5R RS-232 Connections ...............................................................................5-26

Table 5-14 GTX 3X5/3X5R ARINC 429 Connections ........................................................................5-27

Table 5-15 GTX 3X45/3X45R RS-422 Connections ...........................................................................5-27

Table 5-16 GTX 345/345R HSDB Connections ...................................................................................5-28

Table 6-1 GTX 3X5 Connector Kit Hardware ......................................................................................6-4

Table 6-2 Standard/G1000 Mount Back Plate Hardware .....................................................................6-4

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

Table 6-4 Garmin Altitude Encoder Kit - P/N 011-03080-00 ............................................................6-15

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

Table B-1 Ground Plane Definitions and Ground Path Resistance Requirements ...............................B-2

Table B-2 Composite Airframe Bonding Hardware ............................................................................. B-6

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
Rev. 6 Page viii

1 INTRODUCTION

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

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

1.3 Applicability ....................................................................................................................... 1-2

1.4 Publications......................................................................................................................... 1-2

1.5 Revision and Distribution ...................................................................................................1-2

1.6 Reference ............................................................................................................................ 1-3

1.6.1 Terminology.................................................................................................................. 1-3

1.6.2 Acronyms...................................................................................................................... 1-3

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. 6 Page 1-2

, website.

or by

.

1.6 Reference

1.6.1 Terminology

Except where specifically noted, references made to the GTX 33X or GTX 3X5 will apply to the
GTX 330/330D/33/33D or GTX 335/335R/345/345R 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 WAAS: Wide Area Augmentation System

GTX: Garmin Transponder

I/O: Input/Output

SRM: Structural Repair Manual

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 335/335R ................................................................................................................... 2-6

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

2.5 GTX 335R/345R 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 345/345R 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 345

 GTX 335R

 GTX 345R

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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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
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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

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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
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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

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2.3 GTX 335/335R

The GTX 335/335R 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 335/335R 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 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 or GTX 335R. 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
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GTX 335/335R

GPS Antenna

GPS Source

Audio Panel

Bottom Antenna

GTX 3X5 with GPS only

GTX 335R

Control

Power/Ground

Altitude Source

Heading Source

Air Data Source

Secondary GPS

Radio Altitude

Source

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Squat Switch

Garmin Altitude

Encoder

OR

Temperature

External Ident

External Standby

Traffic System

For XPDR Cross-Talk

Keep Alive Input

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Figure 2-3 GTX 335 or GTX 335R Interface Summary

2.4 GTX 345/345R

The GTX 345/345R 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 345/345R 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 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 or GTX 345R. Refer to
GTX 3XX Part 23 AML STC Installation Manual for interfaces allowed under this STC.

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TAS/TCAS I

Traffic Sensor

ADS-B Traffic
FIS-B Display

Bluetooth Device

GTX 345/345R

GPS Antenna

GPS Source

Audio Panel

Bottom Antenna

GTX 3X5 with GPS only

GTX 345R

Control

Power/Ground

Altitude Source

Heading Source

Air Data Source

Secondary GPS

Radio Altitude

Source

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Squat Switch

Bluetooth

External Traffic

Annunciator

For No Display Install

Garmin Altitude

Encoder

OR

Temperature

External Ident

External Standby

Keep Alive Input

Figure 2-4 GTX 345 or GTX 345R Interface Summary

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2.5 GTX 335R/345R with Legacy G1000

Bluetooth Device

GTX 335R/345R

GPS Antenna

Audio Panel

Bottom Antenna

GTX 3X5 with GPS only

Power/Ground

GIA #1

Existing LRU

New LRU

Legend

Optional GTX 345R

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

The Legacy G1000 configuration includes certain G1000 systems that can be updated with a G1000
interface card. The GTX 335R provides all the functions listed under the GTX 335/335R to include
ADS-B Out. The GTX 345R provides all the functions listed under the GTX 345/345R 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 provides FIS-B weather (NEXRAD and METARS) and TIS-B traffic within the
confines of the GDL 90 interface. The GTX 345R 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 or GTX 345R interface for the legacy G1000
system.

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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Figure 2-5 GTX 335R or GTX 345R 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

Input current, maximum 0.86 A 0.43 A

Input current, typical 0.72 A 0.36A

GTX 335, GPS

Input current, maximum 1.22 A 0.61 A

Input current, typical 0.72 A 0.36 A

GTX 345

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

Specification

14 VDC 28 VDC

65 µA typical 20 µA typical

85 µA maximum 40 µA maximum

190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance Manual
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3 GTX CONTROL AND OPERATION

NOTE

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

3.2 GTX 335/345 ...................................................................................................................... 3-5

3.3 GTX 33/33D and GTX 335R/345R.................................................................................... 3-8

3.4 GTX 335R/345R with Legacy G1000 ................................................................................ 3-9

3.5 GTX 3X5 Install Tool....................................................................................................... 3-12

3.5.1 State Page.................................................................................................................... 3-13

3.5.2 Status Page.................................................................................................................. 3-14

3.5.3 Configuration Group................................................................................................... 3-15

3.5.4 Diagnostics Group ...................................................................................................... 3-16

3.5.5 Product Data Group .................................................................................................... 3-18

3.5.6 Software Upload Group .............................................................................................. 3-18

Control and operation of GTX 330/330D and GTX 335/345 units occur through the front panel of the
GTX. Control and operation of the remote mounted GTX 33/33D and GTX 335R/345R 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/345R 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
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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.

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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.

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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 CLR keys.

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.

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3.2 GTX 335/345

NOTE

Figure 3-2 GTX 335/345 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 335/345 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 335/345 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 (R). 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 335/345 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 (R).

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.

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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 3X
GTX 3X5 Install Tool, refer to section 3.5.

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Rev. 6 Page 3-6

5 units may also be configured using the GTX 3X5 Install Tool. For configuration using the

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 when configured for Bluetooth at

installation. When enabled, allows PED pairing to the GTX 345 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,
selected by ENT key. Turns the extended squitter function on or off.

and

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