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

GTX 3X5 Part 27 AML

Maintenance Manual

Contains Instructions for Continued Airworthiness

for STC SR02124SE

Rotorcraft make, model, registration number, and serial

number and accompanying STC configuration information in

Appendix A must be completed and saved with rotorcraft

permanent records.

190-00734-21 February 2020 Revision 2

© 2020 Garmin International or its subsidiaries

All Rights Reserved

Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted,
disseminated, downloaded, or stored in any storage medium for any purpose without the express prior
written consent of Garmin. Garmin hereby grants permission to download a single copy of this manual and
of any revision to this manual onto a hard drive or other electronic storage medium to be viewed and to
print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of this
manual or revision must contain the complete text of this copyright notice and provided further that any
unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited.

®

Garmin

is a registered trademark of Garmin International or its subsidiaries. GDU™ and GTN™ are
trademarks of Garmin International or its subsidiaries. These trademarks may not be used without the
express permission of Garmin.

®

Adobe

© 2020 Bluetooth

is a registered trademark of Adobe Systems Incorporated. All rights reserved.

®

word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any
use of such marks by Garmin is under license. Other trademarks and trade names are those of their
respective owners.

At Garmin, we value your opinion. For comments about this guide, please e-mail:

[e-mail]

.

For information regarding the Aviation Limited Warranty, refer to Garmin’s website.

Garmin International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Telephone: [phone]
Aviation Dealer Technical Support Line (Toll Free): [phone]

www.garmin.com

Garmin (Europe) Ltd.
Liberty House
Bull Copse Road
Hounsdown Business Park
Southampton, SO40 9LR, UK
Telephone: [phone]
Fax: [phone]
Aviation Support: [phone]

Garmin AT, Inc.
2345 Turner Rd. SE
Salem, OR 97032 USA
Telephone: [phone]

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A

RECORD OF REVISIONS

Revision Revision Date Revision Summary

1 11/11/16 Initial release of document.

2

2/17/20

Added new GTX 345 part numbers and added new helicopter
models. Corrected formatting errors.

CURRENT REVISION DESCRIPTION

Section Description

2.4

4.2 Updated wording and ODA STC Unit Administrator.

4.6

5.2 Updated GTX 3X5 Transponder Alert Flowcharts and added sheet 5.

A.3.4 Added EC-135T3 and EC-135P3 models.

Added GTX 345 NV Panel Mount and GTX 345 NV GPS Panel Mount to Table 2-2
Equipment Weights.

Added note to include straps and aluminum foil with measurement during electrical
bonding test.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page B

INFORMATION SUBJECT TO EXPORT CONTROL LAWS

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.

Information in this document can change without notice. Go to Garmin’s website fly
updates and supplemental information about the operation of Garmin units.

DEFINITIONS OF WARNINGS, CAUTIONS, AND NOTES

WARNING

A Warning means that injury or death is possible if the instructions are not
obeyed.

CAUTION

A Caution means that damage to the equipment is possible.

NOTE

A Note provides more information.

WARNING

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

Garmin.com for

.

WARNING

Perchlorate Material - special handling may apply.
Refer to www.dtsc.ca.gov./hazardouswaste/perchlorate

.

CAUTION

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

NOTE

Screen shots are intended to provide visual reference only. All information depicted in
screen shots, such as software file names, versions, and part numbers, is subject to change
and may not be up-to-date.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page i

TABLE OF CONTENTS

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

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

1.2 Organization ...............................................................................................................................1-3

1.3 Applicability...............................................................................................................................1-4

1.4 Publications ................................................................................................................................1-4

1.5 Revision and Distribution...........................................................................................................1-4

1.6 Reference....................................................................................................................................1-5

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

2.1 GTX 335/335R...........................................................................................................................2-2

2.2 GTX 345/345R...........................................................................................................................2-4

2.3 Electrical Load Information .......................................................................................................2-6

2.4 Weight and Balance ...................................................................................................................2-7

2.5 Unit Storage................................................................................................................................2-8

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

3.1 GTX 335/345..............................................................................................................................3-2

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

3.3 GTX 3X5 Install Tool ................................................................................................................3-6

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

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

4.2 Airworthiness Limitations..........................................................................................................4-3

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

4.4 Maintenance/Inspection Intervals ..............................................................................................4-5

4.5 Visual Inspection........................................................................................................................4-6

4.6 Electrical Bonding Test..............................................................................................................4-9

4.7 Additional Instructions...............................................................................................................4-9

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

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

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

5.3 Connector Pinout Information..................................................................................................5-14

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

6.1 GTX 3X5....................................................................................................................................6-2

6.2 Transponder Antenna ...............................................................................................................6-17

6.3 Traffic Annunciator (If Installed).............................................................................................6-17

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

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

7.2 GTX 3X5/3X5R Software Update .............................................................................................7-4

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

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

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

8.3 Configuration .............................................................................................................................8-2

8.4 GTX Test....................................................................................................................................8-3

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

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page ii

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

A.1 Rotorcraft-Specific Information................................................................................................A-2

A.2 Equipment Interfaced to the GTX.............................................................................................A-4

A.3 GTX 3X5 Airframe-Specific Installation................................................................................A-11

A.4 GTX 3X5 Configuration Log..................................................................................................A-28

A.5 GTX 335/335R Configuration Log.........................................................................................A-29

A.6 GTX 345/345R Configuration Log.........................................................................................A-30

APPENDIX B ELECTRICAL BONDING PROCEDURES............................................................... B-1

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page iii

LIST OF FIGURES

Figure 2-1 GTX 335 or GTX 335R Interface Summary ........................................................................2-3

Figure 2-2 GTX 345 or GTX 345R Interface Summary ........................................................................2-5

Figure 3-1 GTX 335/345 Front Panel ....................................................................................................3-2

Figure 3-2 GTN 7XX Transponder Control ...........................................................................................3-5

Figure 3-3 GTN 6XX Transponder Control ...........................................................................................3-5

Figure 3-4 USB A and USB B Connectors ............................................................................................3-6

Figure 3-5 GTX 3X5/3X5R State Page ..................................................................................................3-7

Figure 3-6 GTX 3X5/3X5R Status Page ................................................................................................3-8

Figure 3-7 GTX 3X5/3X5R Configuration Group .................................................................................3-9

Figure 3-8 GTX 3X5/3X5R Diagnostics Group ..................................................................................3-10

Figure 3-9 GTX 3X5/3X5R Product Data Group ................................................................................3-11

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

Figure 5-2 GTX 3X5 Transponder Alerts ..............................................................................................5-4

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

Figure 5-4 Rear View, Connector J3251 ..............................................................................................5-14

Figure 5-5 Rear View, Connector J3252 ..............................................................................................5-16

Figure 6-1 GTX 3X5 Connector Kits .....................................................................................................6-2

Figure 6-2 GTX 3X5 without GPS Backplate Assembly .......................................................................6-3

Figure 6-3 GTX 3X5 with GPS Backplate Assembly ............................................................................6-4

Figure 6-4 GTX 3X5 Vertical Mount without GPS, Backplate Assembly ............................................6-5

Figure 6-5 GTX 3X5 Vertical Mount with GPS, Backplate Assembly .................................................6-6

Figure 6-6 GTX 3X5 Vertical Mount with TNC XPDR Backplate Assembly ......................................6-7

Figure 6-7 Panel-Mounted GTX 3X5 Transponder .............................................................................6-10

Figure 6-8 GTX 3X5R Remote Transponder with Horizontal Mount .................................................6-12

Figure 6-9 GTX 3X5R Remote Transponder with Vertical Mount .....................................................6-14

Figure 6-10 Garmin Altitude Encoder with Backplate Assembly ..........................................................6-16

Figure 6-11 Traffic Annunciator Installation .........................................................................................6-18

Figure 7-1 GTX 3X5 Start-Up Screen ....................................................................................................7-2

Figure 7-2 GTX 3X5 Product Data Page ...............................................................................................7-2

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

Figure 7-4 Install Tool Dialog Box ........................................................................................................7-4

Figure 7-5 GTX 3X5 Install Tool Software Upload Page ......................................................................7-5

Figure A-1 Rotorcraft-Specific Information ..........................................................................................A-2

Figure A-2 Interfaced Equipment Table ................................................................................................A-5

Figure B-1 Aluminum Tape Joint .......................................................................................................... B-2

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page iv

LIST OF TABLES

Table 1-1 Reference Documentation ....................................................................................................1-4

Table 2-1 GTX Electrical Load .............................................................................................................2-6

Table 2-2 Equipment Weights ..............................................................................................................2-7

Table 4-1 Maintenance/Inspection Intervals .........................................................................................4-5

Table 5-1 J3251 Pinout .......................................................................................................................5-14

Table 5-2 J3252 Pinout .......................................................................................................................5-16

Table 5-3 GTX 3X5/3X5R Encoded Altitude Pin Assignments ........................................................5-17

Table 5-4 GTX 3X5/3X5R Discrete Outputs ......................................................................................5-18

Table 5-5 GTX 3X5/3X5R Configurable Output Pins .......................................................................5-18

Table 5-6 GTX 3X5/3X5R Discrete Inputs ........................................................................................5-19

Table 5-7 GTX 3X5/3X5R Configurable Input Pins ..........................................................................5-19

Table 5-8 GTX 3X5/3X5R RS-232 Connections ...............................................................................5-20

Table 5-9 GTX 3X5/3X5R ARINC 429 Connections ........................................................................5-20

Table 5-10 GTX 3X5/3X5R RS-422 Connections ...............................................................................5-20

Table 5-11 GTX 345/345R HSDB Connections ...................................................................................5-21

Table 6-1 GTX 3X5 Connector Kit ......................................................................................................6-2

Table 6-2 Standard Mount Backplate (P/N 011-02976-00 and -01) .....................................................6-3

Table 6-3 Vertical Mount Backplate (P/N 011-02976-10) ...................................................................6-5

Table 6-4 Vertical Mount Backplate (P/N 011-02976-11) ...................................................................6-6

Table 6-5 Vertical Mount Backplate (P/N 011-02976-12) ...................................................................6-7

Table 6-6 GTX 3X5 Transponder Parts List .........................................................................................6-9

Table 6-7 Garmin Altitude Encoder Kit (P/N 011-03080-00) ............................................................6-16

Table 6-8 Traffic Annunciator Installation .........................................................................................6-18

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page v

1 INTRODUCTION

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

1.2 Organization......................................................................................................................................1-3

1.3 Applicability .....................................................................................................................................1-4

1.4 Publications.......................................................................................................................................1-4

1.5 Revision and Distribution.................................................................................................................1-4

1.6 Reference ..........................................................................................................................................1-5

1.6.1 Terminology...............................................................................................................................1-5

1.6.2 Acronyms ...................................................................................................................................1-5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 1-1

1.1 Content, Scope, and Purpose

This document provides Instructions for Continued Airworthiness (ICA) of the GTX 3X5 with ADS-B
functionality installed and compliant to ADS-B Out Version 2 under AML STC SR02124SE. This document
satisfies the requirements for continued airworthiness as defined by 14 CFR Part 27.1529 and 14 CFR Part 27
Appendix A. Information in this document is required to maintain the continued airworthiness of the GTX 3X5.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 1-2

1.2 Organization

The following outline briefly describes the organization of this manual:

Section 2: System Overview

 Equipment features
 Electrical load information
 Weight and balance

Section 3: Control and Operation

 Controlling the GTX
 Using the GTX 3X5 Install Tool

Section 4: Instructions for Continued Airworthiness

 Applicability
 Airworthiness limitations
 Service information
 Maintenance intervals
 Bonding test

Section 5: Troubleshooting

 General troubleshooting
 Failure annunciations
 Connector pinout information

Section 6: Unit Removal and Re-Installation

 Removal and re-installation of the GTX
 Removal and re-installation of the Garmin Altitude Encoder
 Removal and re-installation of the transponder antenna
 Removal and re-installation of the traffic annunciator (if installed)

Section 7: Software

 Software check
 Software update

Section 8: System Configuration and Checkout

 System checkout
 Configuration
 GTX tests

Section 9: System Return to Service Procedure

 Maintenance records

Appendix A: Rotorcraft-Specific Information

 Rotorcraft-specific information form
 Equipment interfaced to the GTX
 Wire routing
 Configuration logs

Appendix B: Special Bonding Procedures

 Surface preparation
 Aluminum tape repair and replacement considerations

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 1-3

1.3 Applicability

This document applies to all rotorcraft with the GTX 3X5 installed in accordance with STC SR02124SE.
Modification of a rotorcraft by this Supplemental Type Certificate (STC) obligates the rotorcraft operator
to implement the specific maintenance practices and/or airworthiness limitations provided in this
document. This is in addition to the rotorcraft’s existing approved maintenance, inspection, and
airworthiness limitations programs.

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
rotorcraft.

Table 1-1 Reference Documentation

Document Garmin P/N Applicable Sections

GTX 3X5 Part 27 AML STC Equipment List

GTN 625/635/650 Pilot’s Guide

GTN 725/750 Pilot’s Guide

005-00734-A5 All

190-01004-03 2.1 and 15.3.2

190-01007-03 2.1 and 16.3.2

1.5 Revision and Distribution

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

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

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

.

website.

or by contacting a

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 1-4

1.6 Reference

1.6.1 Terminology

Except where specifically noted, references made to the GTX 3X5 will apply to the GTX 335/335R/345/
345R. 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 rotorcraft. For the purposes of this manual,
metallic rotorcraft will be those with an aluminum skin. Nonmetallic rotorcraft refers to all other rotorcraft
(e.g., rotorcraft with composite skin).

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

The term squitter refers to a burst or broadcast of data that is transmitted periodically by a Mode S
transponder without interrogation.

1.6.2 Acronyms

AC: Advisory Circular HAT: Height Above Terrain

ADC: Air Data Computer ICA: Instructions for Continued Airworthiness

ADS-B: Automatic Dependent Surveillance -

Broadcast

AHRS: Attitude Heading Reference System I/O: Input/Output

AML: Approved Model List MFD: Multifunction Display

ATC: Air Traffic Control PED: Portable Electronic Device

ATCRBS: Air Traffic Control Radar Beacon System SBAS: Satellite-Based Augmentation System

EGNOS: European Geostationary Navigation

Overlay Service

ES: Extended Squitter SRM: Structural Repair Manual

FAA: Federal Aviation Administration STC: Supplemental Type Certificate

FIS-B: Flight Information System-Broadcast TAS: Traffic Advisory System

GAE: Garmin Altitude Encoder TCAS: Traffic Alert and Collision Avoidance

GNS: Garmin Navigation System TIS: Traffic Information Service

GNSS: Global Navigation Satellite System TSO: Technical Standard Order

GPS: Global Positioning System UAT: Universal Access Transceiver

GTN: Garmin Touchscreen Navigator VSWR: Voltage Standing Wave Ratio

GTX: Garmin Transponder WAAS: Wide Area Augmentation System

ICAO: International Civil Aviation Organization

SPI: Special Position Identifier

System

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 1-5

2 SYSTEM DESCRIPTION

2.1 GTX 335/335R .................................................................................................................................2-2

2.2 GTX 345/345R .................................................................................................................................2-4

2.3 Electrical Load Information..............................................................................................................2-6

2.4 Weight and Balance..........................................................................................................................2-7

2.5 Unit Storage ......................................................................................................................................2-8

Garmin 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. GTX
345/345R units include ADS-B In, which provides TIS-B and FIS-B data via UAT and 1090 MHz. 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 the family of GTX 3X5 transponders.

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

 GTX 335

 GTX 345

 GTX 335R

 GTX 345R

Automatic Dependent Surveillance-Broadcast (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.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-1

2.1 GTX 335/335R

GTX 335/335R units are panel or remote-mounted units that have 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 have these features:

 Mode S transponder

 ADS-B Out capability

 Optional internal GNSS receiver

 Optional GAE pressure sensor module

 Entry of squawk code and flight ID

 Show squawk code and flight ID

 Show pressure altitude

 Show outside air temp

 Show density altitude

 Show flight timers

 Audio output

 TIS-A traffic output to a compatible display

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

GTX 335/335R units interface through these:

 ARINC 429

 RS-232

 Gray code

 Discrete I/O

Figure 2-1 provides a summary of the interfaces provided for the GTX 335 or GTX 335R. For interfaces
approved by this STC, refer to GTX 3X5 Part 27 AML STC Installation Manual.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-2

GTX 335/335R

GPS Antenna

GPS Source

Audio Panel

Bottom Antenna

GTX 3X5 with GPS only

OR

GTX 335R

Control

Power/Ground

Altitude Source

Heading Source

Air Data Source

Secondary GPS

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Garmin Altitude

Encoder

OR

Temperature

External Ident

External Standby

Traffic System

For XPDR cross-talk

Required if HAT is

Not Available

Collective Switch

Radar Altitude

Source

OR

Aircraft Battery

Keep Alive input from aircraft battery
source for internal G PS o nly

Figure 2-1 GTX 335 or GTX 335R Interface Summary

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-3

2.2 GTX 345/345R

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

GTX 345/345R units have these 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 GAE pressure sensor module

 Entry of squawk code and flight ID

 Show squawk code and flight ID

 Show pressure altitude

 Show outside air temp

 Show density altitude

 Show flight timers

 Audio output

 Bluetooth interface to show weather and traffic on portable devices

The transponder provides an ADS-B failure message to alert the crew that the unit has a degraded ADS-B
(In or Out) system.

GTX 345/345R units interface through these:

 HSDB

 ARINC 429

 RS-232

 RS-422

 Gray code

 Discrete I/O

Figure 2-2 provides a summary of the interfaces provided for the GTX 345 or GTX 345R. For interfaces
approved by this STC, refer to GTX 3X5 Part 27 AML STC Installation Manual.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-4

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

OR

GTX 345R

Control

Power/Ground

Altitude Source

Heading Source

Air Data Source

Secondary GPS

Existing LRUNew LRU

Legend

Optional Interfaces

Required Interfaces

Bluetooth

External Traffic

Annunciator

For NO display Install

Garmin Altitude

Encoder

OR

Keep Alive input from aircraft battery
source for internal GPS only

Temperature

External Ident

External Standby

Required if HAT is

Not Available

Collective Switch

Radar Altitude

Source

OR

Aircraft Battery

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-5

2.3 Electrical Load Information

Table 2-1 contains electrical load information for the GTX. Circuit protection for the GTX is located
within the rotorcraft’s avionics circuit protection and is labeled “XPDR.” Appendix A contains details
specific to the load changes for the installation.

Table 2-1 GTX Electrical Load

Unit Characteristic

GTX 335

GTX 335, GPS

GTX 345

GTX 345, GPS

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

Input current, typical 0.57 A 0.29 A

Input current, maximum 0.86 A 0.43 A

Input current, typical 0.72 A 0.36 A

Input current, maximum 1.22 A 0.61 A

Input current, typical 0.72 A 0.36 A

Input current, maximum 1.30 A 0.65 A

Input current, typical 1.07 A 0.54 A

Input current, maximum 1.43 A 0.72 A

65 µA typical 20 µA typical

85 µA maximum 40 µA maximum

Specification

14 VDC 28 VDC

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-6

2.4 Weight and Balance

Update the rotorcraft Equipment List to indicate any items that are added, removed, or relocated. Each
change must include the date and the name and certificate number of the person making the entry.
Table 2-2 contains equipment weights.

Table 2-2 Equipment Weights

Kit P/N Description

010-01214-01 GTX 335 Panel Mount 2.8 / 1.27

010-01214-21 GTX 335 NV Panel Mount 2.8 / 1.27

010-01214-41 GTX 335 GPS Panel Mount 2.9 / 1.32

010-01216-01 GTX 345 Panel Mount 3.1 / 1.41

010-01216-41 GTX 345 GPS Panel Mount 3.2 / 1.45

010-01216-21 GTX 345 NV Panel Mount 3.1 / 1.41

010-01216-61 GTX 345 NV GPS Panel Mount 3.2 / 1.45

010-01215-01 GTX 335 Remote 2.5 / 1.13

010-01217-01 GTX 345 Remote 2.9 / 1.32

Weight

(lbs/kg)

010-01215-41 GTX 335 GPS Remote 2.7 / 1.22

010-01217-41 GTX 345 GPS Remote 3.0 / 1.36

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-7

2.5 Unit Storage

The GTX 3X5 transponder unit is qualified for an operating temperature range of -55 ºC to +85 ºC.
Recommended unit storage temperatures (uninstalled) are between 10 ºC and 35 ºC.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 2-8

3 GTX CONTROL AND OPERATION

3.1 GTX 335/345 ....................................................................................................................................3-2

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

3.3 GTX 3X5 Install Tool.......................................................................................................................3-6

3.3.1 State Page ...................................................................................................................................3-7

3.3.2 Status Page .................................................................................................................................3-8

3.3.3 Configuration Group ..................................................................................................................3-9

3.3.4 Diagnostics Group....................................................................................................................3-10

3.3.5 Product Data Group..................................................................................................................3-11

3.3.6 Software Upload Group ...........................................................................................................3-11

Control and operation of GTX 335/345 units occurs through the front panel of the GTX. Control and
operation of remote-mounted GTX 335R/345R units is handled through the external interface provided via
the GTN 6XX/7XX. 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 3-2 and Figure 3-3 show the
transponder control pages.

Important Codes

NOTE

The selected identification code must be entered carefully (either the one assigned by air
traffic control for IFR flight or an applicable VFR transponder code).

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 (rotorcraft 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. A rotorcraft’s transponder code is used for ATC tracking purposes;
therefore, be careful when making routine code changes.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-1

3.1 GTX 335/345

Figure 3-1 GTX 335/345 Front Panel

Function Selection Keys

NOTE

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 rotorcraft.

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 (®). The replies do not include
altitude information.

ALT Altitude mode is automatically selected when the rotorcraft 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 rotorcraft 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 rotorcraft 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.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-2

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 Configuration mode, it 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-up will place the unit into a Ground Test mode that forces the rotorcraft 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 through 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, rotorcraft 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 3.3.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-3

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 through 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 rotorcraft 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 shown on the GTX 345 when configured for Bluetooth at

installation. When selected, it allows PEDs to pair to the GTX 345 and device
management to show 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.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-4

3.2 GTX 335R/345R

Figure 3-2 and Figure 3-3 show the GTX control pages associated with the GTN 6XX/7XX. Refer to the
specific pilot’s guide and cockpit reference guide for details regarding control and function. Part numbers
for these documents are listed in Table 1-1.

Figure 3-2 GTN 7XX Transponder Control

Figure 3-3 GTN 6XX Transponder Control

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-5

3.3 GTX 3X5 Install Tool

86%$ 86%%

NOTE

If the GTX 3X5/3X5R 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.

NOTE

The GTX 3X5 Install Tool pages shown within this manual reflect GTX 3X5 Install Tool
version 2.05. 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 Dealer Resource Center
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 3X5/3X5R. For additional
details, refer to Figure 3-4. To use the GTX 3X5 Install Tool:

1. Remove power from the GTX 3X5/3X5R.

2. Remove power from the display control unit or verify it is in Configuration mode.

3. Connect the USB cable between the GTX 3X5 and the computer.

4. Energize the GTX 3X5/3X5R and run the GTX 3X5 Install Tool.

Figure 3-4 USB A and USB B Connectors

The install tool is used to check equipment status, load software, and configure the unit.

To place a GTX 3X5/3X5R unit in Configuration mode:

1. In the Unit Mode window, change “Normal Mode” to “Configuration Mode.”

2. Click the Set key.

. The

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

The bottom of the install tool displays unit information, such as software version, connection status, and
unit mode. The tool will 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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-6

The Help key provides the following information:

• Part number

• Version number

• Copyright statement

• Software license agreements

3.3.1 State Page

The State page of the GTX 3X5 Install Tool reports the current mode of the GTX 3X5/3X5R, Flight ID,
Squawk Code, and Pressure Altitude. Mode selections include Ground Test and Traffic Test modes.
Standby and Operate test modes are also provided for TCAS.

Figure 3-5 GTX 3X5/3X5R State Page

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-7

3.3.2 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 3-6 GTX 3X5/3X5R Status Page

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-8

3.3.3 Configuration Group

The Configuration group contains the following pages:

 Aircraft page – allows the configuration of basic aircraft configuration and flight ID settings

 Airframe page – allows the configuration of basic airframe configuration and operational options

settings

 Unit page – allows the configuration of identification code, unit options, and display options

 Interfaces page – allows the configuration of serial, A429, discretes, and HSDB settings

 Sensors page – allows the configuration of Garmin Altitude Encoder, GPS, internal AHRS, and

additional sensors

 Audio page – allows the configuration of audio options and alerts

 Display page – allows the configuration of display and key backlight, photocell and lighting bus

curves, and default offsets

NOTE

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

Figure 3-7 GTX 3X5/3X5R Configuration Group

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-9

3.3.4 Diagnostics Group

NOTE

GTX 3X5/3X5R must be in Configuration mode to view connection status or get assert log.

The Diagnostics group contains the following pages:

 DAP page – reports the status of the necessary data supporting ADS-B requirements

 Discretes page – reports the status of discrete inputs, outputs, and allows the user to override the

output pins for testing purposes

 Connection Status page – reports the status of A429 inputs, serial inputs, and HSDB

 Internal GPS page – reports GPS acquisition status and signal strength

 Bluetooth page – reports Bluetooth receiver status and paired devices

 Assert Log page – provides the ability to download assert log for system troubleshooting

Figure 3-8 GTX 3X5/3X5R Diagnostics Group

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-10

3.3.5 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 the altitude encoder serial number

 Configuration page – displays the configuration status of aircraft, unit, wiring, and display CRCs

Figure 3-9 GTX 3X5/3X5R Product Data Group

3.3.6 Software Upload Group

Allows GTX 3X5/3X5R software updates. Refer to Section 7.2 for details.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 3-11

4 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS

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

4.2 Airworthiness Limitations ................................................................................................................4-3

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

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

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

4.4 Maintenance/Inspection Intervals.....................................................................................................4-5

4.5 Visual Inspection ..............................................................................................................................4-6

4.5.1 GTX 335/345 Visual Inspection ................................................................................................4-6

4.5.2 GTX 335R/345R Visual Inspection...........................................................................................4-7

4.5.3 Antenna Visual Inspection .........................................................................................................4-7

4.5.4 Post-Lightning Strike Inspection................................................................................................4-8

4.5.5 Post-Hard Landing Inspection....................................................................................................4-8

4.6 Electrical Bonding Test ....................................................................................................................4-9

4.7 Additional Instructions .....................................................................................................................4-9

This section provides Instructions for Continued Airworthiness for the GTX 3X5 with ADS-B installation.
This section satisfies the requirements for continued airworthiness as defined by 14 CFR Part 27.1529 and
Part 27 Appendix A. Procedures and practices defined in this section are required to maintain the
continued airworthiness of the GTX 3X5 as installed per STC SR02124SE.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-1

4.1 Applicability

This document applies to all rotorcraft equipped with GTX 3X5 units with ADS-B per STC SR02124SE.

Modification of a rotorcraft by this Supplemental Type Certificate (STC) obligates the helicopter operator
to implement the specific maintenance practices and/or airworthiness limitations provided in this
document. This is in addition to the rotorcraft’s existing approved maintenance, inspection, and
airworthiness limitations programs.

Appendix Sections A.1 through A.6 must be filled out by the installer, included as part of FAA Form 337,
and filed with the rotorcraft’s permanent records. These appendices document GTX 3X5 installation
details that are essential to system maintenance and are a part of the rotorcraft Instructions for Continued
Airworthiness. These include:

 General rotorcraft and GTX transponder specific information

 Electrical Load Analysis

 Equipment connected to the installed GTX transponder

 Configuration log of the installed GTX transponder(s) (a printout of the GTX 3X5 configuration

from the GTX 3X5 Installation Tool is also acceptable)

 Location of the GTX 3X5 transponder and connected antenna(s) as installed in the rotorcraft,

including all wire routing

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-2

4.3 Servicing Information

GTX 3X5 LRU maintenance is “on condition” only.

4.3.1 On Condition Servicing

Servicing or replacement may be required if the GTX 3X5/3X5R exhibits symptoms, failures, or alerts as
described in this manual.

4.3.2 Special Tools

The following tools are required to perform the tasks described in this manual:

 Calibrated milliohm meter with an accuracy of +
 Calibrated transponder ramp tester
 Calibrated pitot-static ramp tester
 GTX 3X5 Install Tool
 50 Ω 5 watt antenna load

0.1 mΩ or better

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-4

4.4 Maintenance/Inspection Intervals

NOTE

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

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

Table 4-1 Maintenance/Inspection Intervals

Item Description/Procedure Section Interval

Equipment
removal and
re-installation

Cleaning

Removal and re-installation of GTX LRUs.

The GTX 335/345 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.

6

N/A

On Condition

On Condition

Antenna visual
inspection

Lightning strike ­actual or
suspected

Testing

Equipment visual
inspection

Testing

Electrical
bonding test

Hard landing

Removal and replacement.

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

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

The 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 3X5 must be tested and shown to
comply with Title 14 CFR Part 91.411, 91.413,
and Part 43 Appendices E and F.

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

Inspect the GTX, mounting rack, and rotorcraft
structure.

4.5

4.5

8.4.2

8.4.3

4.5

8.4.2

4.6

4.5.5

On Condition

On Condition

On Condition

Replacement of GPS
Position source(s)

12 Calendar Months

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

10 Years or
2000 hours

On Condition

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-5

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 temporary removal of a unit or units to gain access to connectors. For equipment removal and
replacement, refer to Section 6. For equipment locations, refer to Appendix A. For instructions on
removing access panels, consult the specific rotorcraft maintenance manual.

4.5.1 GTX 335/345 Visual Inspection

During normal rotorcraft inspections, but not to exceed 12 calendar month intervals, conduct a visual
inspection of the GTX 335/345 installation in the following locations:

Instrument Panel or Console

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

2. Inspect GTX 335/345 unit(s) for security of attachment.

3. Inspect GAE (if installed) for security of attachment.

4. Inspect GTX rack and fasteners for integrity.

a. The racks, fasteners, and support structure must be in good condition and the fasteners secured

properly.

b. There must be no corrosion.

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

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

a. Inspect all GTX and adjacent 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 GTX and adjacent wiring show no signs of cracking, chafing, abrasion,

melting, or any other form of damage.

c. Inspect the GTX rack and LRU 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.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-6

4.5.2 GTX 335R/345R Visual Inspection

During normal rotorcraft inspections, but not to exceed 12 calendar month intervals, conduct a visual
inspection of the GTX 335R/345R installation in the following locations:

Remote Mount Rack

1. Inspect GTX 335R/345R unit(s) for security of attachment.

2. Inspect GAE (if installed) for security of attachment.

3. Inspect GTX rack and fasteners for integrity.

a. The racks, fasteners, and support structure must be in good condition and the fasteners

properly secured.

b. There must be no corrosion.

c. For a composite shelf, aluminum foil tape used to ground the GTX must not be torn, damaged,

or corroded. If any of these occur, 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. Verify that all GTX wiring and cables are securely fastened.

b. Verify that the GTX and adjacent wiring show no signs of cracking, chaffing, abrasion,

melting, or any other form of damage.

c. Inspect the GTX rack and LRU 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.

4.5.3 Antenna Visual Inspection

During normal rotorcraft inspection, but not to exceed 12 calendar months, visually inspect the transponder
antenna(s) for the following:

1. Erosion of the antenna blade leading edge, cracks, dents, or other physical damage. If any of these
conditions are present, the antenna must be replaced. For antenna replacement details, refer to the
antenna manufacturer’s instructions.

2. Secure attachment of the antenna to the rotorcraft structure. If the attachment is not secure,
re-work the installation and complete the electrical bonding test, as described in the applicable
antenna installation instructions.

3. Condition of the environmental seal at the base of the antenna. A damaged or compromised seal
must be replaced and the electrical bonding tested, as described in the applicable antenna
installation instructions.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-7

4.5.4 Post-Lightning Strike Inspection

An inspection must be performed following a suspected or actual lightning strike to antennas or any
sensor(s) connected to the GTX unit. The antenna, sensor, and rotorcraft structure to which they are
mounted must be inspected for physical damage, particularly the location(s) where lightning may have
attached. If visible physical damage is present, the antenna and sensor must be replaced.

The coax cable connecting the antenna to the GTX unit must be inspected, including grounding fasteners,
bonding straps, or aluminum tape. The rotorcraft structure supporting the installation of the remotely
mounted GTX must be inspected to verify that no physical damage has occurred. If damaged, the structure
must be repaired in accordance with the model-specific rotorcraft structural repair manual or the rotorcraft
manufacturer’s instructions. Damaged components must be replaced, followed by completion of the
electrical bonding test described in Section 4.6.

4.5.5 Post-Hard Landing Inspection

An inspection must be performed following a hard landing. The GTX, mounting rack, and rotorcraft
structure to which they are mounted must be inspected for physical damage, particularly the location(s) of
the mounting hardware. If visible physical damage is present, the GTX, mounting rack, and rotorcraft
structure must be replaced or repaired in accordance with the model-specific rotorcraft structural repair
manual or the rotorcraft manufacturer’s instructions. Any component repair or replacement must be
followed by completion of the electrical bonding test described in Section 4.6.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-8

4.6 Electrical Bonding Test

1. Disconnect all connectors from the GTX 3X5. This includes the antenna coaxial cable.

2. Measure the DC resistance between the aircraft ground and the metal case of the GTX 3X5.
Verify that the resistance is less than or equal to 10 mΩ.

NOTE

Any grounding straps or aluminum foil added as part of the GTX 3X5 installation for
grounding the GTX to the airframe ground must be included in the measurement.

3. If the resistance is more than 10 mΩ, the electrical bond must be improved such that the direct
current resistance, when measured with a 4-wire meter, is less than or equal to 2.5 mΩ. For
instructions on how to create a new electrical bond, refer to Appendix B.

4.7 Additional Instructions

Electrical load information for the GTX is provided in Section 2.3.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 4-9

5 TROUBLESHOOTING

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

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

5.3 Connector Pinout Information ........................................................................................................5-14

5.3.1 GTX 3X5..................................................................................................................................5-14

5.3.2 Altitude Functions....................................................................................................................5-17

5.3.3 Discrete Functions....................................................................................................................5-18

5.3.4 RS-232 Input/Output................................................................................................................5-20

5.3.5 ARINC 429 Input/Output.........................................................................................................5-20

5.3.6 RS-422 Out...............................................................................................................................5-20

5.3.7 HSDB Input/Output..................................................................................................................5-21

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-1

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 rotorcraft 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 rotorcraft permanent
records.

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-2

Chec k and verify t he

integrity of the

trans ponder -altitude

encod er interf ace,

inc luding w iring and

alt itu de encoder

operat ion

Chec k and ve rify

integrity of the
antenna ins tallat ion,
ground planes , and

coaxial cable

Ensure the XPDR

cir cuit breaker is

closed

Tes t coaxial cables for

ins ertio n loss and V SW R.

VS WR should be check ed

with an in-line type VSWR/

wat tmeter inserte d in the

coax ial tra nsm is si on l ine

betw een the transpo nder and

the ant enna. The VS WR

shoul d be 1.5:1 at 1090 MH z

or le ss . Inserti on los s shoul d

be less than 1.5 dB at

1090 M Hz

GTX Sym ptom

Transponder audio too

quiet/loud

Incorrec t Mode S aircraft

data tra nsmitted

Transponder will not turn

on

Transponder will not come

out of standb y

Chec k for pro per

elec tric al bondi ng/

grounding of t he

antenna ins tallat ion

Co rrecti ve

Action

Co rrecti ve

Action

Co rrecti ve

Action

Cor recti ve

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 inco rrect altitude
reporti ng by the tran sponde r

Verify transp onder

sel ect swi tc h posi tion ,

(#1 or #2) if installed

Chec k th e
conf iguration mode
settings and reset if

necessary

Verify that the GTX

volume setting is at or

above the minimum

required set ting

Poor transponder

performance. Weak or

intermittent radar contact

reported by ATC

Verify connections

for power and groun d

Verify t he u nsw itched

audio input at the

audio panel sett ing is

at o r ab ove the

minimum required

setting

Chec k the alti tude

sourc e conf igurat ion

on the GTX. Verify
primary and secondary
sourc es are configur ed

properly

Verify the Flight ID and

ICAO address are

conf igured proper ly

Verify t he Tail num ber

and I C AO address are

properly conf igured

Figure 5-1 GTX Transponder Troubleshooting (All Models)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-3

5.2 GTX Failure Annunciations

GTX 3X5 Messages

If fault still exists,

contact Garmin.

Transponder

OR

1090 ADS-B

Out

1090 MHz

Transmitter

Failure

1030 MHz

Receiv er Failure

Failure

ICAO Address

Failure

Loss, damaged,

incorrec t wiring

Incorrect antenna
Internal failure

ICAO address is

incorrec t

Caus e

Verify transponder

antenna,

co nnections , and

coax ins tallation

Inspect

suppression bus

wiring

Inspect wiring

Reload software

Reset config and

config module

Re-configur e u nit

Verify t ransponder

antenna,

connections, and

coax inst allation

Inspect

suppression bus

wiring

Inspect wiring

Reload soft ware

Reset config and

config module

Re-configur e u nit

Enter proper ICAO

address

Reload software

Corrective

Action

Transponder

OR

1090 ADS-B

Out

Failure

Caus e

Loss, damaged,

incorrect w iring

Incorrect antenna
Internal failure

Corrective

Action

Transponder

OR

1090 ADS-B

Out

Failure

Caus e

Corrective

Action

Configuration

Failure

Transponder

configuration data

is invalid or
incomplete

Reload softw are

Reset con fig and

config module.

Re-configur e u nit

Verify the GTX

Install Tool

configuration

summary, correct

any errors

Transponder

OR

1090 ADS-B

Out

Failure

Caus e

Corrective

Action

Calibration

Failure

Factory

transponder

calibration data

invalid

Reload softw are

Reset config and

config module

Re-configure unit

Verify t ransponder

antenna,

connections, and

coax inst allaiton

Inspect wiring,
suppression bus,
and connections

Transponder

OR

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Electrical Fa ilure

Internal voltage

mis-compare with

the unit

Reload softw are

Reset config and

config module.

Re-configure unit

Verify all wi ring,

shorts/opens.

Verify power and

ground

connections

Transponder

OR

10 90 AD S-B

Out

Failure

Cause

Corrective

Action

Frequency Lock

Failure

FPGA has

an error.

Possible internal

hardware i ssue

Reload softw are

Reset config and

config module.

Re-configure unit

Verify t ransponder

antenna,

connections, and

coax inst allation

Inspect wiring,

suppression bus,

and connections

Transponder

OR

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Squitter Monitor

Failure

Error generating

squitter replies.

Possible internal

hardware i ssue

Reload softw are

Reset config and

config module

Re-configure unit

Verify t ransponder

antenna,

connections, and

coax inst allation

Inspect wiring,
suppression bus,
and connections

Transponder

OR

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Reset config and

config module.

Re-configur e u nit

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-4

Figure 5-2 GTX 3X5 Transponder Alerts

Sheet 1 of 5

GTX 3X5 Messages

If fault still exists,

contact Garmin.

Transmit M onitor

Failure

FPGA Failure

- 1090 MHz

transmission

failures

- Internal hardware
problem

- Wiring problem

- Incompatible
antenna

FPGA software did

not load properly

Relo ad software

Reset config and

config module.

Re-configure unit

Verify antenna,

connections, and

coax installation

Inspect wiring,

suppression bus,

and connections

Reload software

Re set co nfi g and

config module.

Re-configure 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

Inte rnal

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

Int ern al

Temperature has

exceeded limits;

Possible internal

damage may have

occured

Failure 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 EQ F

Inte rnal

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
ROM Failure

Software load

issue

Reload software

Transponder

OR

1090 ADS-B

Out

Failure

Cause

Corrective

Action

Reset config and

confi g module.

Re-configure unit

Reset config and

config module.

Re-configure unit

Reset config and

confi g module.

Re-configure unit

Figure 5-2 GTX 3X5 Transponder Alerts

Sheet 2 of 5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-5

GTX 3X5 Messag es

If f ault st ill ex ists,

contact Garmin.

Pre ss ure

Altitude

Pressure

Alt itude Inpu t

Warni ng

Gr ound Tes t

Ground Test

Mode

Pres sure altitude

is not v alid

Verify G TX and

pres sure senso r are

properly configured

Verify wir ing from

pres sure senso r

Verify pr essure

sensor is functioning

If using the GAE,

ver ify connect ions

and then r ecalibrate

Reload softw are

System in Ground

Tes t mode

Power cy cle the GTX

Warning

Cause

Correct ive

Action

Alert

Cause

Corrective

Action

TAS/TCAS

TAS/TCAS

Input Warning

TAS/TCAS is configured
on the GTX and no data

is received or the

TAS/TCAS system is

reporting a failure

Verify TAS/T CAS

sys tem has the r equired

and v alid data

(i.e. Position, Altitude,

Headin g, etc.)

Verify w iring with

TAS/TCAS system

Verify t he TAS/TCAS is

configured properly

Verify th e TAS/TCAS
sy stem ha s not failed

Warning

Cause

Co rrect ive

Action

ADS-B

Position Input

No ADS-B

Position Input

Warni ng

GPS position

unavailable with ADS -B

In and/ or O ut enabled.

(for ADS-B O ut, the unit

is n ot in Standby )

Verify GPS antenna is

SBAS compatible

Verify pos ition s ource is

available, powered on,

and properly configured

Verify G PS antenna
has clear v iew of the

sky

War ning

Cause

Correct ive

Action

Res et co nfig and

config module.

Re-c onfigur e unit

ADS-B In

Traffic

Alerting

CSA Fault

Traffic

Tra ffic

Processing

Fault

Traffi c

ADS-B In

Communication

Fault

ADS -B In pr ocess ing is enabled and
the input data doe s not me et the
perf ormanc e spec ifications .

- GPS horizontal position unavailable

- GPS v elocit y un availa ble

- GPS time u navailable

- HF OM mus t be better than 0.5N M

- Pressure altitude unav ailable or GPS
altitude and VFOM worse than 45m

Verify valid GPS antenna has

clear view of th e sk y

Posit ion s ource is availab le,

properly configured and powered

Verify AD S -B In traffic is pro perly

ins talled a nd c onfigur ed, d isplay

sou rce, heading so urce, GPS

source are all configured

properly

Reset configuration and

configuration module, then re -

configure unit

Reload so ftware

ADS-B In is enabled and an additional
fault has occured.

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

- T AS/TCAS Input W arning

-CSA Fault

-GPS Fault

- P ress ure Altitude Warni ng

- ADS-B In Elec trical Fault

- Internal communication between the
main and ADS -B boards

Ins pect co mpatibilit y of

transponder ant enna and

conn ections

Verify the po sition s ource is

ava ilable, powered on and

properly configured

Reset configur ation and

configuration module, then

re-configur e unit

Reload s oftware

Verify T AS/TCAS sy stem is

not failed

ADS-B In is enabled and an additional
fault has occured.

- ADS-B / AD S -R / TIS-B F ault

- TAS/T CAS Input Warning

- C SA F aul t

- GPS Fault

- Pressure Altitude Warning

- ADS-B In Electrica l Fault

- Internal c ommunication betwe en the
main and ADS -B boards

Faul t

Cause

Co rrect ive

Action

Fault Fault

Cause Cause

Correc tive

Action

Co rrect ive

Action

Inspec t compatibility of

tran sponder antenna and

connections

Rese t configur ation and

configuration module, then

re- configu re unit

Reload so ftware

Verify TAS/TCAS system is

not failed

Verify the pos ition so urce is

avai lable, p owered o n, and

properly configured

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-6

Figure 5-2 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 fa iled

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

compatible

Reload software

Inspect all wiring,

and coaxial cables

ADS-B In enabled

and the 978 MHz

receiver fa iled

Inspect

compatibility of

transponder
antenna and
connections

Reload software

Fault

Cause

Correctiv e

Action

Fault

Cause

Corrective

Action

Fault

Cause

Corrective

Actio n

FIS-B

Weather

978 RX Fault

FIS-B

Weather

ADS-B In

Communication

Fault

FIS-B enabled

and the 978 MHz

receiver failed

Inspect

compatibility of

transponder
antenna and
connections

FIS-B enabled and

the 978 MHz

receiver f ailed

Inspect

compatibility of

transponder

antenna and

connections

Reload software

Fault

Cause

Corrective

Action

Fault

Cause

Correctiv e

Actio n

ADS-B In

Configuration

Fault

ADS-B In

configuration data

did not load or is

invalid

Service Soon

Fault

Cause

Corrective

Actio n

ADS-B In

Electrical Fault

ADS-B In

Calibr ation

Fault

Reload software

Electrical fault with

the ADS-B board.

Possible internal

hardware problem

Check wiring

Factory ADS-B In
calibrat ion data is

invalid

Reload software

Service Soo nService Soon

Fault

Cause

Fault

Cause

Corrective

Action

Corrective

Actio n

Reset config and

config module.

Re-configure unit

Reset config and

config module

Reconfigure unit

Reset config and

config module.

Re-configure unit

Reset config and

config module.

Re-configur e unit

Reset config and

config module.

Re-configure unit

Reset config and

config module.

Re-configure unit

Reload software

Reset config and

config module.

Re-configure unit

Reset config and

config module.

Re-configure unit

Reload software

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-7

Figure 5-2 GTX 3X5 Transponder Alerts

Sheet 4 of 5

GTX 3X5 Messages

If fault stil l exi sts,

contac t G armin.

GPS Fault

GAE

Cali bration

Fault

Backlight

Cali brati on

Fault

Configuration
Mo dul e Fa ult

No GPS data

available

Internal GPS fault

Not connected to

a va lid SBAS/

GPS source

Verify GPS

antenna is SBAS

com patib le

Verify posi tion

source is avail able

and properly

configured

Verify GPS

antenna has clear

view of the sky

Garmin Altitude
Encoder (GAE)

calibration data is

inva lid

Calibrate GAE

Factory calibration

for the di splay is

inv alid

Verify lighting

configuration

Failure of the
configuration

module

Verify module is

installed and

wiring is correct

Service SoonService Soon

Fault

Caus e

Fault

Cause

Service Soon Service Soon

Fault

Cause

Fault

Cause

Corrective

Action

Corrective

Action

Corrective

Action

Corrective

Action

Audio ROM

Fault

Non-volatile

Mem ory Fau lt

Audio database

did not load or is

inv alid

Non-volatile data

did not load or is

inv alid

Service SoonService Soon

FaultFault

CauseCause

Corrective

Action

Corrective

Action

Service Soon

Suppressio n

Bus Fault

Fault on the

suppression bus

Ch eck fo r

inc ompati ble LRU

on suppression

line (DME)

Verify suppr ession

bus wiring for

shorts or opens

Fault

Cause

Corrective

Action

ADS-B In

FPGA ROM

Fault

ADS-B In FPGA
software di d not
load or is invalid

Service Soon

Fault

Caus e

Corrective

Action

Reset config and

config module.

Re-configur e unit

ADS-B In

ROM Fault

ADS-B In software

did not load or is

inv alid

Reload software

Service Soon

Fault

Caus e

Corrective

Action

Reset config and

config module.

Re-configur e unit

Reset config and

config module.

Re-configure unit

Reset config and

config module.

Re-configure unit

Reload software Reload software Reload software

Reset config and

config module.

Re-configur e unit

Reload software

Re set co nfig and

config module.

Re-configur e unit

Reload software

Reset config and

config module.

Re-configure unit

Reload software

Figure 5-2 GTX 3X5 Transponder Alerts

Sheet 5 of 5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-8

GTX 3X5 Install Tool

Fail ure Messages

If fault still exists,

cont ac t G armin.

RAM Failure

Squitter Monitor

Failure

Cause

High Temperature

Failure

Cause

Corrective

Action

The main board or

transmitter board

temperature is

above 80° C.

Allow the unit to

cool down to less

than 70

° C.

Frequency Lock

Failur e

Cause

The units

synthesizer

cannot lock the

desired

frequency.

Re-ins tall transponder

soft ware and

conf iguration.

Software did not install

correctly. Possible

internal memory

damage.

Corrective

Acti on

Low Temperature

Failure

Cause

Corrective

Actio n

The main board or

transmitter board

temperature is

below -45° C.

Allow the unit to

warm up to

greater than

-35

° C.

Calibration Failure

Configuration

Failure

FPGA Failure

FPGA ROM

Failur e

Transponder
ROM Failure

Software did not

install correctly.

Pos sibl e int ernal

memory damage.

Corrective

Actio n

Re-ins tall transponder

soft ware and

conf iguration.

Cause

Elec trical Failure

Figure 5-3 GTX 3X5 Install Tool Failure/Fault Messages

Sheet 1 of 5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-9

978 RX Fault*

Cause

Correcti ve

Action

GTX 3X5 In stall Tool

Failure Me ssages

ICAO Address

Failu re

Cause

If fault still exists,

contact Garmin.

Bad cable connection.

Correcti ve

Action

Verif y ant enna cable i s

not disconnected ,

damaged, or all owing

pin t o shield contact.

Cause

Transmit

Monit or Failure

ICAO address is all

ones or zeros.

Corrective

Acti on

Enter correct ICAO

address.

1090 RX Fault*

Cause

The 1090 M Hz receiver has

fail ed the 1090 MHz receive

test.

Correcti ve

Action

Inspect cables and

connections to

transponder anten na.

Note:

*For GTX 345 only.

1090 TX Failure

Sup pr es sion Bu s

Fau lt

Cause

Inspect transponder

antenna, suppression

bus cable s, and

connectors.

Loose, damaged, or

incorr ect wirin g.

Possible internal

failure.

Cor rec tive

Acti on

1030 RX Failure

The 978 M Hz receiver has
fail ed t he 978 MHz receive

test.

Inspect cables and

connections to

transponder ant enna.

ADS-B In

Communication

Fau lt*

Cause

Corrective

Action

There is an internal

communication failure

between the main board

and the A DS-B board.

Relo ad ADS- B

Software.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-10

Figure 5-3 GTX 3X5 Install Tool Failure/Fault Messages

Sheet 2 of 5

Re-install main and

ADS-B software.

GTX 3X5 I nstall Tool

Failure Messages

ADS-B In processing is enabled and any of t he
following are t rue:

- Posit ion is unavailable

- Inst alled TA S/ TCAS system is report ing f ailed
(the 1090 M Hz receiver has f ailed the 1090 MHz
receiver t est AND the 978 MHz receiver ha s
failed t he 978 MHz receiver t est)

- Int ernal ADS-B board power failure has been
detected

Cause

Corrective

Action

If fault still exists,

contact Garmin.

ADS-B/ADS-R/

TIS-B Fault*

Cause

Corrective

Action

The 1090 MHz

receiver has failed the

1090 MHz receiver

test AND The 9 78
MHz re ce ive r has

failed the 978 MHz

receiver test.

Inspect cables

and connections

to transponder

antenna.

Re-install main

and A DS-B

software.

CSA Fault*

Cause

Corrective

Acti on

The input data does

not meet required

performance

specifications or is

invalid.

No ADS-B

Position Input

Warning

Cause

Corrective

Acti on

ADS-B In and/or

Out is enabled
and position is

unavailable.

Ensure position

source is available,

properly

configured, and

powered on.

Ensu re GPS

antenna has a

clear, unobstructed

view of the sky.

No TAS/TCAS
Input Warning*

Cause

Corrective

Acti on

No messages have

been received from an

installed TAS/TCAS

system or the system

is reporting failed.

Inspect

connections to

TAS/TCAS

system. Ensure

TAS/TCAS

system is

functioning

properly.

Note:

*For GTX 345 only.

Traffic

Processing

Fau lt*

No Pressure

Altitude Warning

Cause

Corrective

Acti on

Pressure altitude

is invalid.

Inspect

connections to

pressure sensor.

Verify pressure

sensor is

functioning

properly.

Figure 5-3 GTX 3X5 Install Tool Failure/Fault Messages

Sheet 3 of 5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-11

GTX 3X5 Install Tool

Failure Messages

If fault still exists,

contact Garmin.

ADS-B In

Configuration

Fault*

ADS-B In ROM

Fault*

Cause

Test Mode

Cause

Corrective

Action

Unit is operating in

Test mode.

Reload transponder

and ADS-B software.

Check configuration

settings.

The GTX 3X5 has

detected a fault during

the internal power -up

integ rity check.

Correct ive

Action

ADS-B In FPGA

ROM Fault*

Audio ROM Fault

Nonvolatile

Memory Fault

Unit is in

Ground Test

mode .

Correct ive

Action

For installer use only.
Cycle power on GTX.

Cause

Ground Test

Mode

GPS Fault

Cause

Inspect cables and

connections to GPS

antenna. Ensure GPS

antenna has clear,

unobstructed view of sky.

The GTX 3X5 has

detected a fault during

the internal power-up

integrity check.

Corrective

Action

ADS-B In

Electrical Fault*

Note:

*For GTX 345 only.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-12

Figure 5-3 GTX 3X5 Install Tool Failure/Fault Messages

Sheet 4 of 5

ADS-B In

Calibration Data

Fault*

Backlight

Calibration Fault

Cause

The GTX 3X5 has

detected a fault during

the internal power-up

integrity check.

Corrective

Action

GAE Calibration

Fault

Configuration

Module Fault

GTX 3X5 Install Tool

Failure Messages

Contact Garmin.

Note:

*For GTX 345 only.

Figure 5-3 GTX 3X5 Install Tool Failure/Fault Messages

Sheet 5 of 5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-13

5.3 Connector Pinout Information

59 58 57 56

5

5

54 53 52 51 434450 49 48 47 46 45

62

61

60

25 24 23 22

262728293031323334

3536373839

404142

1

23

45

67891011131415

1617

12

192021 18

5.3.1 GTX 3X5

Figure 5-4 Rear View, Connector J3251

Table 5-1 J3251 Pinout

Pin GTX 3X5 Pin Name I/O

1 ALT ENCODER/CONFIG MODULE CLOCK I/O

2 USB DATA HI I/O

3 TEMP PROBE IN IN

4 TIME MARK A I/O

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 I/O

16 CONFIGURABLE DISCRETE 2 I/O

17 XPDR FAIL 1 OUT

18 EXTERNAL SUPPRESSION I/O

19 LIGHTING BUS HI IN

20 ROTORCRAFT GROUND IN

21 ROTORCRAFT POWER 1 IN

22 ALT ENCODER/CONFIG MODULE DATA I/O

23 ALT ENCODER/CONFIG MODULE GND IN

24 USB DATA LO I/O

25 TEMP PROBE OUT OUT

26 TIME MARK B I/O

27 ARINC 426 IN 1A IN

28 ARINC 429 IN 1B IN

29 RS-232 IN 3 IN

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-14

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 ROTORCRAFT GROUND --

42 ROTORCRAFT POWER 1 --

43 ALT ENCODER/CONFIG MODULE POWER --

44 USB VBUS POWER I/O

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 ROTORCRAFT POWER 2 --

62 ROTORCRAFT POWER 2 --

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-15

Figure 5-5 Rear View, Connector J3252

5 4 3 2 1

10 9 8 7 6

15 14 13 12 11

Table 5-2 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 I/O

14 CONFIGURABLE DISCRETE 12 I/O

15 RS-232 GND 4 --

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-16

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 Ω. 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 5-3 GTX 3X5/3X5R Encoded Altitude Pin Assignments

Pin Pin Name I/O Connector

13 ALTITUDE D4 IN J3251

10 ALTITUDE A1 IN J3251

32 ALTITUDE A2 IN J3251

53 ALTITUDE A4 IN J3251

11 ALTITUDE B1 IN J3251

33 ALTITUDE B2 IN J3251

54 ALTITUDE B4 IN J3251

12 ALTITUDE C1 IN J3251

34 ALTITUDE C2 IN J3251

55 ALTITUDE C4 IN J3251

56 ALTITUDE COMMON -- J3251

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-17

5.3.3 Discrete Functions

Discrete Outputs

Table 5-4 GTX 3X5/3X5R Discrete Outputs

Pin Pin Name I/O

17 TRANSPONDER FAIL 1 OUT All J3251

18 EXTERNAL SUPPRESSION I/O All J3251

X REPLY ACTIVE OUT All J3251/J3252

X TRANSPONDER FAIL #2 OUT All J3251/J3252

X ALTITUDE ALERT* OUT All J3251/J3252

X EQUIPMENT STATUS OUT All J3251/J3252

X TRAFFIC ALERT OUT 345/345R J3251/J3252

X TRAFFIC STANDBY OUT 345/345R J3251

X TRAFFIC TEST OUT 345/345R J3251

X TCAD SENSITIVITY OUT 345/345R J3251/J3252

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

ACTIVE: V

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 5-5 for a list of configurable output pins.

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

in

Unit (335/345/

335R/345R)

Connector

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

Pin Pin Name I/O

17 TRANSPONDER FAIL #1 OUT All J3251

15 CONFIGURABLE DISCRETE #1 I/O All J3251

16 CONFIGURABLE DISCRETE #2 I/O All J3251

13 CONFIGURABLE DISCRETE #11 I/O 345/345R J3252

14 CONFIGURABLE DISCRETE #12 I/O 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-18

Discrete Inputs

Table 5-6 GTX 3X5/3X5R Discrete Inputs

Pin Pin Name I/O

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

X ALTITUDE SOURCE* IN All J3251/J3252

X AUDIO INHIBIT #1* IN All J3251/J3252

37 AUDIO INHIBIT #2* IN All J3251

58 AIR DATA SOURCE* IN All J3251

57 SQUAT IN All J3251

36 IDENT* IN All J3251

14 STANDBY* IN All J3251

13 INSTALL ID SELECT IN All J3251

18 EXTERNAL SUPPRESSION I/O I/O All J3251

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

ACTIVE: V

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

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 5-7 for a list of configurable input pins.

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

in

Unit (335/345/

335R/345R)

Connector

Table 5-7 GTX 3X5/3X5R Configurable Input Pins

Pin Pin Name I/O

37 AUDIO INHIBIT #2 IN All J3251

58 AIR DATA SELECT IN All J3251

57 SQUAT SWITCH IN All J3251

36 EXTERNAL IDENT IN All J3251

14 EXTERNAL STANDBY IN All J3251

18 EXTERNAL SUPPRESSION I/O I/O All J3251

15 CONFIGURABLE DISCRETE #1 I/O All J3251

16 CONFIGURABLE DISCRETE #2 I/O All J3251

13 CONFIGURABLE DISCRETE #11 I/O 345/345R J3252

14 CONFIGURABLE DISCRETE #12 I/O 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-19

5.3.4 RS-232 Input/Output

Table 5-8 GTX 3X5/3X5R RS-232 Connections

Pin Pin Name I/O

9 RS-232 OUT 1 OUT All J3251

31 RS-232 IN 1 IN All J3251

8 RS-232 OUT 2 OUT All J3251

30 RS-232 IN 2 IN All J3251

7 RS-232 OUT 3 OUT All J3251

29 RS-232 IN 3 IN All J3251

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

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

Unit (335/345/

335R/345R)

5.3.5 ARINC 429 Input/Output

Table 5-9 GTX 3X5/3X5R ARINC 429 Connections

Pin Pin Name I/O

27 ARINC 429 IN 1A IN All J3251

Unit (335/345/

335R/345R)

Connector

Connector

28 ARINC 429 IN 1B IN All J3251

5 ARINC 429 OUT 1A OUT All J3251

6 ARINC 429 OUT 1B OUT All J3251

48 ARINC 429 IN 2A IN All J3251

49 ARINC 429 IN 2B IN All J3251

5.3.6 RS-422 Out

Table 5-10 GTX 3X5/3X5R RS-422 Connections

Pin Pin Name I/O

11 RS-422 A OUT 345/345R J3252

12 RS-422 B OUT 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-20

5.3.7 HSDB Input/Output

Table 5-11 GTX 345/345R HSDB Connections

Pin Pin Name I/O

6 ETHERNET OUT 1A OUT 345/345R J3252

7 ETHERNET IN 1A IN 345/345R J3252

1 ETHERNET OUT 1B OUT 345/345R J3252

2 ETHERNET IN 1B IN 345/345R J3252

8 ETHERNET OUT 2A OUT 345/345R J3252

9 ETHERNET IN 2A IN 345/345R J3252

3 ETHERNET OUT 2B OUT 345/345R J3252

4 ETHERNET IN 2B IN 345/345R J3252

Unit (335/345/

335R/345R)

Connector

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 5-21

6 UNIT REMOVAL AND RE-INSTALLATION

6.1 GTX 3X5 ..........................................................................................................................................6-2

6.1.1 GTX 335/345 Panel-Mounted Units ..........................................................................................6-8

6.1.2 GTX 3X5R with Horizontal Install Rack.................................................................................6-11

6.1.3 GTX 3X5R with Vertical Install Rack.....................................................................................6-13

6.1.4 Garmin Altitude Encoder .........................................................................................................6-15

6.2 Transponder Antenna......................................................................................................................6-17

6.3 Traffic Annunciator (If Installed) ...................................................................................................6-17

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-1

6.1 GTX 3X5

GTX 3X5

GTX 345/345R Only

P3252

1

2

4

3

2

5

7

4
2

6

This section contains parts, procedures, and requirements for assembly, removal, and re-installation of
GTX 3X5 equipment installed under STC SR02124SE. After removal and re-installation, the GTX 3X5
return to service procedures must be performed in accordance with Section 9. After re-installation of the
GTX 3X5, verify that the electrical bond is equal to or less than 2.5 mΩ, per Section 4.6.

Table 6-1 GTX 3X5 Connector Kit

Item Description P/N Qty

1 Connector, hi-dense, D-Sub, mil crimp 62 ckt

2 Sub-assembly, backshell with hardware, 37/62 pin

3 Sub-assembly, ground adapter, shell 4&5

4 Screw, 4-40 X 0.250, FLHP 100, SS/P, nylon

5 Connector, hi-dense, D-Sub, mil crimp, 15 ckt

6 Sub-assembly, backshell with hardware, 9/15 pin

7 Sub-assembly, ground adapter, shell 1-3

330-00185-62

011-00950-03

011-01169-01

211-63234-06

330-00185-15

011-00950-00

011-01169-00

1

1

1

2 ea connector

1

1

1

P3251

Figure 6-1 GTX 3X5 Connector Kits

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-2

For a list of the backplate items associated with the standard mounting assembly, refer to Table 6-2. For

3

1

2

NUT SUPPLIED
WITH ITEM 2

5
4

detailed drawings of the backplate assembly, refer to Figure 6-2 and Figure 6-3.

Table 6-2 Standard Mount Backplate (P/N 011-02976-00 and -01)

Item Description P/N Qty

DCP, connector plate, GTX 3X5, w/secondaries

1

Connector, male/female special, BNC

2

Washer, shoulder, GNC 400

3

Connector, male/female, special, BNC/TNC

4

Screw, 4-40 X 0.250, PHP, SS/P, nylon

5

125-00307-10 1

330-00053-01 1

212-00022-00 2

330-00053-02 1

211-60234-08 4

Figure 6-2 GTX 3X5 without GPS Backplate Assembly

(P/N 011-02976-00)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-3

Figure 6-3 GTX 3X5 with GPS Backplate Assembly

1

2

4

3
2

NUTS SUPPLIED
WITH ITEMS 2 & 4

5
4

(P/N 011-02976-01)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-4

For a list of the backplate items associated with the vertical mounting assembly, refer to Table 6-3. For

1

2



NUT SUPPLIED
WITH ITEM 2







detailed drawings of the backplate assemblies, refer to Figure 6-4, Figure 6-5, and Figure 6-6.

Table 6-3 Vertical Mount Backplate (P/N 011-02976-10)

Item Description P/N Qty

DCP, connector plate, remote, GTX 3X5, w/secondaries

1

Connector, male/female special, BNC

2

Washer, centering, no float

3

Washer, split lock, size 8

4

Screw, captive, 8-32, 0.62", 3/32 hex drv

5

125-00343-10 1

330-00053-01 1

212-00022-10 1

212-00018-04 2

211-00290-00 2

Figure 6-4 GTX 3X5 Vertical Mount without GPS, Backplate Assembly

(P/N 011-02976-10)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-5

Table 6-4 Vertical Mount Backplate (P/N 011-02976-11)

2

1



3

4

NUTS SUPPLIED
WITH ITEMS 2 & 4







Item Description P/N Qty

DCP, connector plate, remote, GTX 3X5, w/secondaries

1

Connector, male/female special, BNC

2

Washer, shoulder, GNC 400

3

Connector, male/female, special, BNC/TNC

4

Washer, centering, no float

5

Washer, split lock, size 8

6

Screw, captive, 8-32, 0.62", 3/32 hex drv

7

125-00343-10 1

330-00053-01 1

212-00022-00 2

330-00053-02 1

212-00022-10 1

212-00018-04 2

211-00290-00 2

Figure 6-5 GTX 3X5 Vertical Mount with GPS, Backplate Assembly

(P/N 011-02976-11)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-6

Table 6-5 Vertical Mount Backplate (P/N 011-02976-12)



1



NUT SUPPLIED
WITH ITEM 4









Item Description P/N Qty

DCP, connector plate, remote, GTX 3X5, w/secondaries

1

Connector, male/female, special, BNC/TNC

2

Washer, centering, no float

3

Washer, split lock, size 8

4

Screw, captive, 8-32, 0.62", 3/32 hex drv

5

125-00343-10 1

330-00053-02 1

212-00022-10 1

212-00018-04 2

211-00290-00 2

Figure 6-6 GTX 3X5 Vertical Mount with TNC XPDR Backplate Assembly

(P/N 011-02976-12)

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-7

6.1.1 GTX 335/345 Panel-Mounted Units

CAUTION

Ensure that the rotorcraft 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 335/345
panel-mounted units installed under STC SR02124SE. After removal and re-installation, the GTX 335/345
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 inches.

2. Pull the unit straight out of the rack.

Re-Installation

CAUTION

Be sure not to overtighten the unit into the rack. Torque exceeding 8 in-lbf can damage the
locking mechanism.

NOTE

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 1 inch short of the final position.

2. Insert a 3/32” 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, not exceeding 8 in-lbf of
torque. Be careful not to overtighten. 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.

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-8

For a complete list of GTX 3X5 transponder components, refer to Table 6-6. For detailed assembly
drawings, refer to Figure 6-7, Figure 6-8, and Figure 6-9.

Table 6-6 GTX 3X5 Transponder Parts List

Item Description P/N

GTX 335 Standard Kit

GTX 335 NV Standard Kit

1

GTX 335 GPS, Standard Kit

GTX 345, Standard Kit

GTX 345 GPS, Standard Kit

GTX 335 Remote, Standard Kit

GTX 335 Remote GPS, Standard Kit

2

GTX 345 Remote, Standard Kit

GTX 345 Remote GPS, Standard Kit

GTX 335 Remote, Vertical Mount, Standard Kit

GTX 335 Remote GPS, Vertical Mount, Standard Kit

3

GTX 345 Remote, Vertical Mount, Standard Kit

GTX 345 Remote GPS, Vertical Mount, Standard Kit

Screw, machine, flat, countersunk head 100 degrees, cross-recessed,

4

0.1380-32UNC-2A

010-01214-01

010-01214-21

010-01214-41

010-01216-01

010-01216-41

010-0215-01

010-0215-41

010-0217-01

010-0217-41

010-0215-02

010-0215-42

010-0217-02

010-0217-42

MS24693-S26

OR

OR

OR

Nut, self-locking, plate, one lug, reduced rivet spacing, low height,

5

steel, 0.138-32 UNC-3B

Rivet, solid, countersunk 100 degrees, precision head, 3/32 in. OD,

6

3/16 in. long

Nut, self-locking plate, two-lug, reduced rivet spacing, low height, steel,

7

0.138-32 UNC-3B

Screw, machine, flat, countersunk head, 100 degrees, cross-recessed,

8

0.1900-32 UNF-2A, 0.625 in. long

Insert, screw thread, molded-in, blind threaded, self-locking, floating,

9

sandwich panel, 0.190-32 UNJF-3B

10 GAE 12 Altitude Encoder, Standard Kit

11 Adapter, straight, 1/8 in. pipe to 1/4 in. hose

MS21071-06

MS20426AD3-3

MS21069L3

MS24693-S273

NAS1835A-3

011-03080-00

AN840-4D

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-9

Figure 6-7 Panel-Mounted GTX 3X5 Transponder

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-10

6.1.2 GTX 3X5R with Horizontal Install Rack

CAUTION

Ensure that the rotorcraft 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/345R
equipment installed using a standard remote mount. After removal and re-installation, the
GTX 335R/345R 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 inches.

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

Re-Installation

CAUTION

Be sure not to overtighten the unit into the rack. Torque exceeding 8 in-lbf can damage the
locking mechanism.

NOTE

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 into the rack until it stops about 1 inch short of the final position.

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

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

5. Count the number of complete revolutions the hex screw can be turned, not exceeding 8 in-lbf of
torque. Be careful not to overtighten. 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.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-11

Figure 6-8 GTX 3X5R Remote Transponder with Horizontal Mount

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-12

6.1.3 GTX 3X5R with Vertical Install Rack

CAUTION

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

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

Removal

1. Access the transponder.

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

3. Carefully remove the backplate 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 on the base plate.

5. Tilt the unit so that the toe of the GTX 3X5 shoe fully disengages 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 tab on the base plate.

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

5. Carefully install the backplate onto the unit.

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

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-13

Figure 6-9 GTX 3X5R Remote Transponder with Vertical Mount

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-14

6.1.4 Garmin Altitude Encoder

CAUTION

Ensure that the rotorcraft power is off before removal or re-installation of the
GTX 3X5/3X5R. Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and installation of the Garmin Altitude
Encoder equipment installed under STC SR02124SE. After removal and re-installation, the
GTX 3X5/3X5R return to service procedures must be performed in accordance with Section 9.

Removal

1. Remove the transponder. Refer to Section 6.1 for details.

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

3. Disconnect wiring harness at the altitude encoder.

4. Remove the two screws securing the unit to the backplate.

Installation

1. Secure the altitude encoder to backplate assembly with two screws; torque to 8 in-lbf.

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 6.1 for details.

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

6. Complete the static system and transponder checks described in Section 8.4.2.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-15

Table 6-7 Garmin Altitude Encoder Kit (P/N 011-03080-00)

1

2

Item Description P/N Qty

1 Sub-assembly, altitude encoder, unit only

2 Screw, 4-40 X 0.250, PHP, SS/P, w/nyl

011-03080-01 1

211-60234-08 2

Figure 6-10 Garmin Altitude Encoder with Backplate Assembly

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-16

6.2 Transponder Antenna

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

6.3 Traffic Annunciator (If Installed)

CAUTION

Ensure that the rotorcraft power is off before removal or re-installation of the
GTX 3X5/3X5R. Unplug any auxiliary power supply.

This section contains procedures and requirements for removal and installation of the Vivisun Traffic
annunciator installed under STC SR02124SE. After removal and installation, the Traffic annunciator return
to service procedures must be performed in accordance with Section 9.

Removal

1. Disconnect all annunciator wiring.

2. Remove the annunciator indicator cap by applying pressure on the two sides of the switch cap and
pulling the switch cap from the switch body.

3. Gently remove the cap pins from the hinged slide retainer.

4. From the front of the indicator, locate the two slotted head integral mounting screws. Loosen the
two screws and remove the locking sleeve from the back of the indicator.

5. Pull the indicator out through the front of the mounting panel.

Installation

1. Insert the indicator body through the front of the mounting panel.

2. Slide the locking sleeve onto the indicator body until it touches the mounting panel.

3. From the front of the switch body, locate the two slot head integral mounting screws in the base of
the body. Tighten the two screws until the mounting sleeve is pulled against the panel. Torque 18
to 25 inch-ounces.

4. Reconnect all annunciator wiring.

5. Push in transponder circuit breaker.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-17

Table 6-8 Traffic Annunciator Installation

1

2

3

Item Description P/N Qty

1 Annunciator, Traffic, Vivisun

2 Plug, Quick Connect, Vivisun

3 Mounting Sleeve (Part of Annunciator)

LED-40-17-HAI-E1G30 1

18-200 1

Figure 6-11 Traffic Annunciator Installation

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 6-18

7 SOFTWARE

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

7.1.1 GTX 3X5 Software Version Check ...........................................................................................7-2

7.1.2 GTX 3X5R Software Version Check (GTN 6XX/7XX) ...........................................................7-3

7.2 GTX 3X5/3X5R Software Update....................................................................................................7-4

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 7-1

7.1 Software Check

NOTE

It is essential that the software version is correct. 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.

NOTE

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

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

7.1.1 GTX 3X5 Software Version Check

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 7-1 for details.

Figure 7-1 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 on the STC Equipment List. Refer
to Figure 7-2 for details.

Figure 7-2 GTX 3X5 Product Data Page

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 7-2

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

NOTE

The following procedures provide an overview to verify the software version of the
GTX 3X5R when interfaced with the GTN 6XX/7XX.

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

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

3. Verify the version number matches the approved version listed on the STC Equipment List.

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

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 7-3

7.2 GTX 3X5/3X5R Software Update

CAUTION

If the unit is removed from the rotorcraft 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
below must be carried out on each GTX.

Software may be loaded by performing the following steps on the GTX Install Tool Software Upload page.
Refer to Figure 7-5.

1. Download the GTX 3X5/3X5R software from the Garmin Dealer Resource Center

2. Under “Step 1 - Select a File,” select the Browse key. Locate the Boot Block software file
containing the previously downloaded GTX 3X5/3X5R software.

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

4. Under “Step 3 - Start Upload,” select the Upload key.

5. Wait for the 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. Locate the Main System software file
containing the previously downloaded GTX 3X5/3X5R software.

7. Under “Step 2 - Upload Options,” select the “In File” versions to be updated.

8. Under “Step 3 - Start Upload,” select the Upload key.

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

10. After successful completion, verify that the correct software versions and part numbers display on
the Transponder page of the Product Data group.

a. To view the Product Data group, it may be necessary to exit the Software Upload page and

select Configure Transponder. Refer to Figure 7-4.

. For dual GTX installations, the software loading procedures

.

Figure 7-4 Install Tool Dialog Box

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 7-4

Figure 7-5 GTX 3X5 Install Tool Software Upload Page

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 7-5

8 SYSTEM CONFIGURATION AND CHECKOUT

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

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

8.3 Configuration....................................................................................................................................8-2

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

8.3.2 GTX 3X5R Configuration (GTN 6XX/7XX)............................................................................8-2

8.4 GTX Test ..........................................................................................................................................8-3

8.4.1 Airborne Mode ...........................................................................................................................8-3

8.4.2 Regulatory Test ..........................................................................................................................8-4

8.4.3 ADS-B Out Test.........................................................................................................................8-4

8.4.4 Traffic Annunciator Test (If Installed).......................................................................................8-5

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 8-1

8.1 Overview

NOTE

EMI Testing is required as part of the post-installation checkout. It is not required as part
of regular maintenance.

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 Re-Installed

If the original GTX is being re-installed, configuration and software loading are not required. Continue to
the GTX Test described in Section 8.4.

New, Repaired, or Exchanged GTX is Installed

If a new, repaired, or exchanged GTX is installed, AML approved software (refer to Section 7.1 and
Section 7.2) must be loaded to the unit.

8.3 Configuration

NOTE

Ensure the Post-Installation Checkout Log remains with the rotorcraft permanent records
upon completion of any maintenance activities.

Retrieve the Post-Installation Checkout Log from the rotorcraft permanent records. For the maintenance
activities that repaired or replaced the previous GTX, verify the configuration of the GTX as defined by the
data contained in the Post-Installation Checkout Log.

8.3.1 GTX 3X5 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 internally in the GTX 3X5 unit and in the
configuration module located in the rack connector backshell. To exit the configuration pages, turn the
power off. Then turn on again (without holding the ENT key) for normal operation.

8.3.2 GTX 3X5R Configuration (GTN 6XX/7XX)

For GTX 3X5R installations interfacing to a GTN 6XX/7XX, configuration of the GTX is accomplished
through the GTX Installation Tool. Within the GTX Installation Tool, an Offline mode is available under
the GTX menu that allows configuration as if a unit is connected. This allows for the saving, loading, and
generating summaries of configuration. Refer to Section 7.2 for instructions on downloading, installing,
and connecting the installation tool to the GTX 3X5/3X5R unit.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 8-2

8.4 GTX Test

NOTE

For dual transponder installations, the procedures contained in this section must be
completed for each installed transponder.

Operation of the GTX 3X5 is accomplished using the faceplate of the unit. Refer to Section 3.1for details.
The GTX 3X5R is controlled using the GTN 6XX/7XX. Refer to Section 3.2 for details. Refer to the
operational documents listed in Table 1-1 for basic GTX operation.

8.4.1 Airborne Mode

The transponder must be placed in an airborne state to reply to any Mode A or Mode C interrogations. The
GTX uses advanced Air/Ground logic to determine the state of the transponder. This logic must be
temporarily defeated in order to place the transponder in an airborne state for testing. To place the
transponder into an airborne state, perform the following applicable procedure.

Panel-Mounted Transponder

1. Start the GTX in Ground Test mode (hold the CRSR key and press the ON key).

2. “GROUND TEST MODE” alert message will be displayed on the GTX 3X5 message screen.

Remote-Mounted Transponder (GTN Interface)

NOTE

A GTX or GTN in Ground Test mode or Airborne Test mode will automatically return to
normal operation of the Air/Ground logic when the unit is powered off and then turned on
in Normal mode. When the unit is in Ground Test or Airborne Test mode, an alert message
will be annunciated on the GTX or GTN screen.

1. Start the GTN in Configuration mode (hold the HOME key while cycling power).

2. Navigate to the XPDR 1 Installation Settings page.

a. Select External Systems.

b. Select XPDR.

3. Press the Force Airborne Test key.

4. Restart the GTN in Normal mode.

Remote-Mounted Transponder (GTX 3X5R Only)

NOTE

Airborne Test mode is for testing purposes only. Once testing is complete, either return the
collective switch to original settings or remove the GTX from Ground Test mode.

1. Connect the GTX 3X5 installation tool to GTX 3X5R unit.

2. Place unit into Ground Test mode located on the State page.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 8-3

8.4.2 Regulatory Test

With the transponder operating in Normal mode and in an Airborne or Ground Test state (refer to
Section 8.4.1), the following regulatory tests are required to be performed every 24 calendar months, or
any time the transponder is removed, replaced, or modified.

1. Altitude reporting equipment tests in accordance with 14 CFR Part 91.411 and Part 43
Appendix E.

2. ATC transponder tests and inspections in accordance with 14 CFR Part 91.413 and Part 43
Appendix F.

These regulatory tests require the use of a Mode S transponder ramp tester, such as an Aeroflex IFR-6000
or TIC TR-220. Specific instructions for operating the ramp tester are contained in the applicable
operator's manual.

8.4.3 ADS-B Out Test

NOTE

Software version 5.30 or later is required on the TR-220.

The following ADS-B Out parameters must be verified in accordance with Title 14 of the Code of Federal
Regulations (14 CFR) § 91.227 any time the position source (GPS) is replaced/modified. The test is
performed using a transponder ramp test set, such as the Aeroflex IFR-6000 or TIC TR-220. For
instructions on operating the ramp tester, refer to the manufacturer’s documentation.

1. Ensure the rotorcraft is in a location where a GPS signal can be received (i.e., outdoors with a clear
view of the sky).

2. Power on the rotorcraft/avionics and ensure that the GTX is powered on.

3. If the GTX is configured for pilot control of the ADS-B transmitter, ensure ADS-B TX is selected
ON.

4. Temporarily put the GTX into Airborne mode. Refer to Section 8.4.1.

5. If dual GPS sources are connected to the GTX, each GPS source must be checked separately by
disabling the GPS source not being checked. Disable the GPS source not being checked by
covering the GPS antenna or removing power from that navigator. Verify that the GPS source not
being checked is no longer receiving satellite data.

6. Ensure the GPS source being checked has acquired a position.

7. Select ALT mode on the GTX.

8. Using the transponder test set, verify the following ADS-B Out parameters are being transmitted:

 NACv ≥ 1

 SDA ≥ 2

 SIL ≥ 3

 NACp ≥ 8

 NIC ≥ 7

9. If dual GPS sources are connected to the GTX, repeat steps 5 through 8 for the other GPS source.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 8-4

10. Revert the GTX to its previous configuration as follows:

a. If a connected air/ground switch was defeated in step 4, then place the connected switch back

to the on-ground position.

b. If the GTX squat switch configuration settings were changed in step 4, revert the GTX settings

back to the previous configuration.

11. Select STBY mode on the GTX.

If no other service is to be performed, continue to the return to service checks in Section 9.1.

8.4.4 Traffic Annunciator Test (If Installed)

To test the annunciator, press the Traffic Test key on the GTX 3X5 Install Tool State page, and verify that
the “Traffic” annunciator illuminates.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 8-5

9 SYSTEM RETURN TO SERVICE

After removing and re-installing or replacing the GTX 3X5, perform the system checkout procedures in
Section 8.2.

9.1 Maintenance Records

After performing the required return to service procedures, a record of maintenance should be provided to
the owner/operator in accordance with 14 CFR 43.9 and 14 CFR 91.417.

The following should be provided in the maintenance record entry:

 Part number and version number of any software updates performed during maintenance

 Part number and serial number of any LRU that was replaced

 Any other applicable information related to the maintenance work performed on the rotorcraft

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page 9-1

APPENDIX A INSTALLATION-SPECIFIC INFORMATION

A.1 Rotorcraft-Specific Information .........................................................................................................A-2

A.2 Equipment Interfaced to the GTX ......................................................................................................A-4

A.3 GTX 3X5 Airframe-Specific Installation .........................................................................................A-11

A.3.1 Airbus Helicopters AS-350, AS-350B, AS-350B2, AS-350B3, AS-350BA, and AS-350D A-12

A.3.2 Airbus Helicopters EC-120B .................................................................................................A-13

A.3.3 Airbus Helicopters EC-130T2 and EC-130B4 ......................................................................A-14

A.3.4 Airbus Helicopters EC-135, EC-135P1, EC-135P2, EC-135P2+, EC-135P3, EC-135T1, EC-

135T2, and EC-135T2+, EC-135T3 ......................................................................................A-15

A.3.5 Agusta A109, A109A, A109A II, A109C, A109K2, A109E, A109S, AW109SP, A119,

and AW119 MKII ..................................................................................................................A-16

A.3.6 Bell 206A and 206B...............................................................................................................A-17

A.3.7 Bell 206L, 206L-1, 206L-3, and 206L-4 ...............................................................................A-18

A.3.8 Bell 407..................................................................................................................................A-19

A.3.9 Bell 427 and 429 ....................................................................................................................A-20

A.3.10 Enstrom Helicopters 480, 480B, F-28, F-28A, F-28C, 280, 280C, 280F, and 280FX..........A-21

A.3.11 MD Helicopters 369, 369D, 369E, 369F, 369FF, and 500N................................................. A-22

A.3.12 MD Helicopter 600N .............................................................................................................A-23

A.3.13 Robinson R22, R22 Alpha, R22 Beta, and R22 Mariner....................................................... A-24

A.3.14 Robinson R44 and R44 II ......................................................................................................A-25

A.3.15 Robinson R66.........................................................................................................................A-26

A.3.16 Sikorsky 269, 269C, 269C-1, and 269D................................................................................ A-27

A.4 GTX 3X5 Configuration Log ...........................................................................................................A-28

A.5 GTX 335/335R Configuration Log...................................................................................................A-29

A.6 GTX 345/345R Configuration Log...................................................................................................A-30

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-1

A.1 Rotorcraft-Specific Information

GENE

5272CRAFT SPECIFIC INFORMATION

RAL INFORMATION

'DWH   %\

5272CRAFT

5272&5$)70$.(

5272&5$)702'(/

5272&5$)76(5,$/

5272&5$)75(*

+(;$''5(66

0RG/HYHO

6HULDO

GTX #2 [N/A] 

0RG/HYHO

6HULDO

GTX #1

8QLW31

8QLW0RGHO

8QLW31

8QLW0RGHO

Figure A-1 Rotorcraft-Specific Information

Sheet 1 of 2

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-2

ELECTRICAL LOAD ANALYSIS

ITEMS REMOVED FROM 5272CRAFT

ELECTRICAL LOAD (A) [1]

COMMENT

Subtotal:

ITEMS ADDED TO 5272CRAFT

ELECTRICAL LOAD (A) [1]

COMMENT

Subtotal

Net Change in Bus Load:

[1] Use typical current draw when performing this calculation.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-3

Figure A-1 Rotorcraft-Specific Information

Sheet 2 of 2

A.2 Equipment Interfaced to the GTX

NOTE

This information is optional and is not required to be completed or maintained with the
rotorcraft records.

Document the equipment that is interfaced to the GTX. Use the following guidance when filling out the
information. When applicable, check that the correct LRU is used for the interface or write in the GTX port
number or numbers used for the interface. This is generally applicable only to serial ports, such as
RS-232 and ARINC 429.

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-4

GTX #1 INTERFACED EQUIPMENT

Manufacturer/Model

GPS

Source

Remote

Control

&

Traffic/

Weather

Altitude

Source

Heading

Source

Radar

Altitude

Source

Traffic

(TAS/TCAS)

Audio
Panel

Data

Forwarding

Garmin
GTX 3X5( )

Garmin
GTN 6XX/7XX

Garmin
GNS 400W/500W

Garmin
G500H (GDU 620)

Garmin
GDL 69A (SXM)

Garmin
GDC 74( )

Garmin
GAE

ACK Tech
A-30

Icarus Instruments
3000

Sandia
SAE 5-35

Shadin
8800T

Shadin
F/ADC-200

Shadin
F/ADC-2000

Shadin
ADC 200+

Trans-Cal Industries
IA-RS232-X

Trans-Cal Industries
SSD120

90004-003

(Bendix King)

(Bendix King)

1000-PFD

ADS-B In

External

B & D

Honeywell

KDC 281
Honeywell

KDC 481
Aspen

Display

Display

Source

Figure A-2 Interfaced Equipment Table

Sheet 1 of 6

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-5

Manufacturer/Model

GPS

Source

Remote

Control

&

Traffic/

Weather

Altitude

Source

Heading

Source

Radar

Altitude

Source

Traffic

(TAS/TCAS)

Audio

Panel

Data

Forwarding

1000H-PFD

EXP 5000

AHS-85E

EFS 40/50 (SG465)

SN 3308

SN 3500

GRS 77( )

GAD 42( )

RA-4500

KRA 405B

GRA 55/5500

TAS 6XX (9900BX)

Skywatch SKY497

Skywatch SKY899

(Bendix King)
KTA 870/810

(Bendix King)
KTA 970/910

GTS 8XX

GTS Processor

SL 10(___)

SL 15(___)

GMA 35( )

ADS-B In

External

Aspen

Avidyne

Collins

Bendix King

Sandel

Sandel

Garmin

Garmin

Free Flight

Honeywell

Garmin

Avidyne (Ryan)

L3

L3

Honeywell

KMH 880/820
Honeywell

Display

Display

Source

KMH 980/920
Garmin

(800/820/850)
Garmin

(825/855)
Garmin

Garmin

Garmin

Figure A-2 Interfaced Equipment Table

Sheet 2 of 6

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-6

Manufacturer/Model

GPS

Source

Remote

Control

&

Traffic/

Weather

Altitude

Source

Heading

Source

Radar

Altitude

Source

Traffic

(TAS/TCAS)

Audio

Panel

Data

Forwarding

GMA 340 / 347

GMA 350

GMA 1347

(Bendix King)

(Bendix King)

King)

(Bendix King)

PMA 6000

PMA 7000

PMA 8000

A710 / A711

DVCS 6100

AMS 42 / AMS 44

AMS 50

ADS-B In

External

Garmin

Garmin

Garmin

Honeywell

KMA 24
Honeywell

KMA 24H-70/71
Honeywell (Bendix

KMA 26
Honeywell

KMA 28
PS Engineering

PS Engineering

PS Engineering

Techinsonics

Becker

NAT

NAT

Display

Display

Source

Figure A-2 Interfaced Equipment Table

Sheet 3 of 6

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-7

GTX #2 INTERFACED EQUIPMENT

Manufacturer/Model

GPS

Source

Remote

Control

&

Traffic/

Weather

Altitude

Source

Heading

Source

Radar

Altitude

Source

Traffic

(TAS/TCAS)

Audio

Panel

Data

Forwarding

Garmin
GTX 3X5()

Garmin
GTN 6XX/7XX

Garmin
GNS 400W/500W

Garmin
G500H (GDU 620)

Garmin
GDL 69A (SXM)

Garmin
GDC 74()

Garmin
GAE

ACK Tech
A-30

Icarus Instruments
3000

Sandia
SAE 5-35

Shadin
8800T

Shadin
F/ADC-200

Shadin
F/ADC-2000

Shadin
ADC 200+

Trans-Cal Industries
IA-RS232-X

Trans-Cal Industries
SSD120

90004-003

(Bendix King)

(Bendix King)

1000-PFD

ADS-B In

External

B & D

Honeywell

KDC 281
Honeywell

KDC 481
Aspen

Display

Display

Source

Figure A-2 Interfaced Equipment Table

Sheet 4 of 6

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-8

Manufacturer/Model

GPS

Source

Remote

Control

&

Traffic/

Weather

Altitude

Source

Heading

Source

Radar

Altitude

Source

Traffic

(TAS/TCAS)

Audio

Panel

Data

Forwarding

1000H-PFD

EXP 5000

AHS-85E

EFS 40/50 (SG465)

SN 3308

SN 3500

GRS 77()

GAD 42()

RA-4500

KRA 405B

GRA 55/5500

TAS 6XX (9900BX)

Skywatch SKY497

Skywatch SKY899

(Bendix King)
KTA 870/810

(Bendix King)
KTA 970/910

GTS 8XX

GTS Processor

SL 10(___)

SL 15(___)

GMA 35( )

ADS-B In

External

Aspen

Avidyne

Collins

Bendix King

Sandel

Sandel

Garmin

Garmin

Free Flight

Honeywell

Garmin

Avidyne (Ryan)

L3

L3

Honeywell

KMH 880/820
Honeywell

Display

Display

Source

KMH 980/920
Garmin

(800/820/850)
Garmin

(825/855)
Garmin

Garmin

Garmin

Figure A-2 Interfaced Equipment Table

Sheet 5 of 6

190-00734-21 GTX 3X5 Part 27 AML Maintenance Manual
Rev. 2 Page A-9