GTX 320/320A
Transponder Installation Manual

190-00133-01

July, 2006

Revision M

Copyright 1999-2006 Garmin Ltd. 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 International, Inc. 1200 E. 151st Street Olathe, KS 66062 USA Telephone: 913-397-8200 Aviation Dealer Technical Support Line (Toll Free): (888) 606-5482 www.garmin.com Garmin (Europe) Ltd. Unit 5, The Quadrangle Abbey Park Industrial Estate Romsey, SO51 9DL U.K. 44/0870.851241
RECORD OF REVISIONS Revision Revision Date
A B C D E F G H J K L M 02/10/97 05/30/97 07/08/97 08/21/97 09/18/97 01/23/98 06/05/98 05/14/99 09/25/00 11/05/01 06/06/02 07/14/06

Description

Initial Rel Clarify Antenna Requirements Lengthens Mount Screws, Add Notes Depth Behind Panel Wiring Diagram Corrections Add Spring Washer Correct reference to 50 ohm match bushing Updates and Corrections Redraw Updates and Clarifications Updated unit and accessory part numbers Corrected date on front cover and misc updates

--40373

Page A Rev. M
GTX 320/320A Installation Manual 190-00133-01
DOCUMENT PAGINATION Section
Table of Contents Section 1 Section 2 Section 3 Appendix A Appendix B Appendix C

Page Range

iii vi 1-1 1-4 2-1 2-10 3-1 3-4 A-1 A-8 B-1 B-2 C-1 C-16
INFORMATION SUBJECT TO EXPORT CONTROL LAWS This document may contain information which is subject to the Export Administration Regulations ("EAR") issued by the United States Department of Commerce (15 CFR, Chapter VII, Subchapter C) and which may not be exported, released, or disclosed to foreign nationals inside or outside of the United States without first obtaining an export license. A violation of the EAR may be subject to a penalty of up to 10 years imprisonment and a fine of up to $1,000,000 under Section 2410 of the Export Administration Act of 1979. Include this notice with any reproduced portion of this document.

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 web site at www.garmin.com/prop65.

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TABLE OF CONTENTS
PARAGRAPH 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 2. 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 PAGE
GENERAL DESCRIPTION.... 1-1 Introduction..... 1-1 Equipment Description..... 1-1 Technical Specifications.... 1-1 Equipment Available.... 1-2 Additional Equipment Required.... 1-3 Installation Approval.... 1-3 ATC Transponder Tests and Inspections... 1-3 Limited Warranty.... 1-4 INSTALLATION OVERVIEW.... 2-1 Introduction..... 2-1 Unpacking and Inspecting Equipment.... 2-1 Antenna Installation.... 2-1 GTX 320/320A Installation.... 2-5 Electrical Connections.... 2-6 Check Existing Coax and Antenna Before Using a GTX320/320A Adapter. 2-8 Installation Using Existing Narco AT 150 Installation Rack.. 2-8 Installation Using Existing Bendix/King 76A/78A Installation Rack... 2-9

3. POST INSTALLATION CONFIGURATION & CHECKOUT PROCEDURE.. 3-1 3.1 Aircraft Station Licensing Requirements... 3-1 3.2 Operation.... 3-1

PARAGRAPH

APPENDIX A, CERTIFICATION DOCUMENTS... A-1 A.1 Continued Airworthiness.... A-1 A.2 Environmental Qualification Form - (GTX 320).... A-4 A.3 Environmental Qualification Form - (GTX 320A)... A-6 APPENDIX B, STC PERMISSION-GTX 320....B-1 APPENDIX C, ASSEMBLY AND INSTALLATION DRAWINGS..C-1

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LIST OF ILLUSTRATIONS
FIGURE 2-1 2-2 3-1 C-1 C-2 C-3 C-4 C-5 C-6 C-7 PAGE
BNC Connector Assembly Drawing.... 2-Pin D-Sub Connector Drawing.... 2-7 Transponder Front Panel (GTX 320 Shown)... 3-1 GTX 320/320A Outline Drawing....C-3 GTX 320/320A Connector/Rack Kit Assembly Drawing...C-5 GTX 320/320A Recommended Panel Cutout Dimensions...C-7 GTX 320/320A Interconnect Wiring Diagram....C-9 GTX 320/320A Dual Transponder Interconnect Wiring Diagram..C-11 Narco AT 150 Installation Adapter Assembly Drawing...C-13 King KT 76A/78A Installation Adapter Assembly Drawing...C-15

LIST OF TABLES

TABLE 1-1 1-2 1-3 1-4 1-5 2-1 2-2 2-3 2-4 A-1 A-2 PAGE
Transponder Specifications.... 1-1 GTX 320 Physical Characteristics.... 1-2 GTX 320A Physical Characteristics... 1-2 Available Configurations.... 1-2 Available Installation Accessories.... 1-3 Antenna Coax Cable, Vendor & Type.... 2-3 Pin Contact Part Numbers..... 2-6 Recommended Crimp Tools.... 2-Pin D-Sub Pin-Out Definitions.... 2-7 Environmental Qualification Form GTX 320.... A-4 Environmental Qualification Form GTX 320A... A-6

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GTX 320 HARDWARE MOD LEVEL HISTORY
The following table identifies hardware modification (Mod) Levels for the GTX 320 Transponder. Mod Levels are listed with the associated service bulletin number, service bulletin date, and the purpose of the modification. The table is current at the time of publication of this manual (see date on front cover) and is subject to change without notice. Authorized Garmin Sales and Service Centers are encouraged to access the most up-to-date bulletin and advisory information on the Garmin Dealer Resource web site at www.garmin.com using their Garmin-provided user name and password.

MOD LEVEL 1 2

SERVICE BULLETIN NUMBER NA 9805
SERVICE BULLETIN DATE NA 10-30-1998

PURPOSE OF MODIFICATION

Initial Release Incorporates new circuitry in power supply
GTX 320A HARDWARE MOD LEVEL HISTORY
The following table identifies hardware modification (Mod) Levels for the GTX 320A Transponder. Mod Levels are listed with the associated service bulletin number, service bulletin date, and the purpose of the modification. The table is current at the time of publication of this manual (see date on front cover) and is subject to change without notice. Authorized Garmin Sales and Service Centers are encouraged to access the most up-to-date bulletin and advisory information on the Garmin Dealer Resource web site at www.garmin.com using their Garmin-provided user name and password.

1.63 inches (41 mm) 6.25 inches (159 mm) 1.71 inches (43 mm) 6.30 inches (160 mm) 8.78 inches (223 mm) 1.7 lbs. (0.8 kg) 2.3 lbs. (1.1 kg)
Physical Characteristics-GTX 320A
Table 1-3 GTX 320A Physical Characteristics
1.63 inches (41 mm) 6.25 inches (159 mm) 1.71 inches (43 mm) 6.30 inches (160 mm) 8.78 inches (223 mm) 2.3 lbs. (1.1 kg) 2.9 lbs. (1.3 kg)

1.4 1.4.1

Equipment Available Available Configurations
Table 1-4 Available Configurations
Garmin GTX 320 Transponder Garmin GTX 320A Transponder Garmin GTX 320 Transponder includes Garmin installation kit, P/N 010-10161-00 Garmin GTX 320A Transponder includes Garmin installation kit, P/N 010-10161-01

Garmin P/N

010-00135-00 010-00247-00 010-00135-03 010-00247-02

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Installation Accessories
Table 1-5 Available Installation Accessories
Mounting Rack Connector Kit Rear Backplate Mounting Rack, Rear Backplate and Connector Kit (Includes 115-00285-00, 011-00677-01 and 011-00651-01) Garmin GTX 320/320A Narco Adapter Garmin GTX 320/320A KT76A Adapter Garmin GTX 320/320A Antenna kit*
115-00285-00 011-00651-01 011-00677-01 010-10161-01 010-10158-00 010-10159-00 010-10160-00
* A transponder antenna approved to TSO C66( ) or C74( ) that has been installed to meet the requirements of this manual may be approved for use with the GTX 320/320A.
Additional Equipment Required
Antenna Sealant - Use antenna manufacturers instructions, install according to FAA AC 43.13-2A. Cables - The installer will supply all system cables. Cable requirements and fabrication is detailed in Section 2 of this manual. Hardware - #6 Flat Head Screw (6 ea.) and #6-32 Self Locking Nut (6 ea.). Hardware required to mount installation rack is not provided.

Installation Approval

The conditions and tests required for TSO approval of the GTX 320/320A Transponder and antenna are minimum performance standards. It is the responsibility of the installer to determine that the aircraft installation standards for a specific type or class of aircraft are in compliance with all applicable TSO requirements. The GTX 320/320A and antenna may be installed only if further evaluation by the applicant documents an acceptable installation and is approved by the administrator. For GTX 320/320A TSO compliance, see Appendix A. For antenna TSO compliance, refer to antenna manufacturers literature.
ATC Transponder Tests and Inspections
The ATC transponder tests required by 14 CFR, Part 91.413 may be conducted using a bench check or portable test equipment and must meet the requirements prescribed in Part 43 Appendix F. If portable test equipment with appropriate coupling to the aircraft antenna system is used, operate the test equipment for ATCRBS transponders at a nominal rate of 235 interrogations per second to avoid possible ATCRBS interference. An additional 3 dB loss is allowed to compensate for antenna coupling errors during receiver sensitivity measurements conducted in accordance with Part 43 Appendix F, Paragraph (c)(1) when using portable test equipment.

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Limited Warranty
This Garmin product is warranted to be free from defects in materials or workmanship for two years from the date of purchase. Within this period, Garmin will at its sole option, repair or replace any components that fail in normal use. Such repairs or replacement will be made at no charge to the customer for parts or labor, provided that the customer shall be responsible for any transportation cost. This warranty does not cover failures due to abuse, misuse, accident or unauthorized alteration or repairs. THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED OR STATUTORY, INCLUDING ANY LIABILITY ARISING UNDER ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM STATE TO STATE. IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE, OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT. Some states do not allow the exclusion of incidental or consequential damages, so the above limitations may not apply to you. Garmin retains the exclusive right to repair or replace the unit or software or offer a full refund of the purchase price at its sole discretion. SUCH REMEDY SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY. To obtain warranty service, contact your local Garmin Authorized Service Center. For assistance in locating a Service Center near you, call Garmin Customer Service at one of the numbers shown below. Products sold through online auctions are not eligible for rebates or other special offers from Garmin. Online auction confirmations are not accepted for warranty verification. To obtain warranty service, an original or copy of the sales receipt from the original retailer is required. Garmin will not replace missing components from any package purchased through an online auction. Garmin International, Inc. 1200 East 151st Street Olathe, Kansas 66062, U.S.A. Phone: 913/397.8200 FAX: 913/397.8282 Garmin (Europe) Ltd. Unit 5, The Quadrangle, Abbey Park Industrial Estate Romsey, SO51 9DL, U.K. Phone: 44/0870.851241 FAX: 44/0870.851251

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INSTALLATION OVERVIEW Introduction
This section provides the necessary information for installing the GTX 320/320A Transponders, and where required, optional accessories. Installation of the GTX 320/320A Transponder should comply with the aircraft Type Certificate (TC) or Supplemental Type Certificate (STC). Cabling will be fabricated by the installing agency to fit each particular aircraft. The guidance of FAA advisory circulars AC 43.13-1B and AC 43.13-2A, where applicable, may be found useful for accomplishing retro-fit installations that comply with FAA regulations. This section contains interconnect diagrams, mounting dimensions, and information pertaining to installation.

Place the ferrule over the coax braid, flush against the coax outer insulation before performing the next step if the outside diameter of the coax braid is smaller than the inside diameter of the center connector sidewall opening. D. Insert cable (center conductor, dielectric and shield braid) through the sidewall of the connector and solder the center conductor to the center pin of the connector.
When using low loss cable it may be necessary to flatten the solid wire center conductor slightly so it can fit the slot on the RF connector center pin. When soldering, avoid applying excess heat to the connector body, and center conductor insulator. E. F. G. Heat the outside of the connector sleeve and at the same time apply solder between the braid and the sleeve. Continue to apply heat until the solder flows evenly. Install 50 Matching Bushing.
Insert connector cap and tack solder in two places.

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GTX 320/320A Installation NOTES
Avoid installing the unit near heat sources. If this is not possible, ensure that additional cooling is provided. Allow adequate space for installation of cables and connectors. The installer will supply and fabricate all of the cables. All wiring must be in accordance with FAA AC 43.13-2A. GTX 320 units that are at Mod Level 1 must use the Mod Level 1 Rack Assembly. After Mod Level 1, GTX 320 installations are 0.170" (4.31 mm) deeper in the panel. A. Assemble the connector/rack kit according to figure B2. Install the rack assembly according to the dimensions given in figures B1. Mounting brackets are not supplied due to the wide range of mounting configurations available. Suitable mounting brackets may be fabricated from sheet metal or angle stock. To ensure a sturdy mount, rear support for the unit should be provided. Do not insert screws through the rear plate of the mounting tray, into the transponder. These holes are only for use with the adapter described in paragraph 2.8. Looking at the bottom of the transponder, make sure the front lobe of the locking mechanism is in a vertical position. This can be accomplished by using a 3/32" Allen wrench through the face plate. Slide the unit into the rack until the front lobe of the unit touches the rack. Guide pins on the back plate will help in the proper alignment of the unit in the rack. Turn the Allen wrench clockwise until unit is secured in the rack. Continue turning until tight. Do not overtighten the screw. To remove the unit from the rack, turn the 3/32" Allen wrench counterclockwise until it disengages from the rack.

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Electrical Connections

All electrical connections, except for the antenna, are made through a single, 25 pin, D subminiature connector. Figure 2-1 defines the electrical characteristics of all input and output signals and identifies the cable requirements for each signal. Required connector and associated hardware are supplied in the installation kit (P/N 010-10160-00). See figures B4 and B5 for interconnect wiring diagrams. Larger pins are supplied for the connector to provide power and ground at pins 13, 14, 15, and 25 when required. Refer to Figure B4, Note 3. Table 2-2 Pin Contact Part Numbers
Manufacturer Garmin P/N Military P/N AMP Positronic ITT Cannon 25 pin D-Subminiature connector (P102) 18 AWG 22-24 AWG (Power Only) 336-00023-00 336-00022-00 N/A M39029/63-368 N/A 205090-1 FC6018D M39029/63-368 See Note 3 031-1007-42
Table 2-3 Recommended Crimp Tools
Manufacturer Hand Crimping Tool

Positioner

18 AWG Insertion/ Extraction Tool M81969/1-02 M81969/1-02 N/A N/A M24308/1-02 M81969/1-02
22-24 AWG Insertion/ Extraction Tool
Military P/N Positronic ITT Cannon AMP Daniels Astro
M22520/2-995-0001-584 601966-1 AFM8 615717
N/A 9502-11 N/A N/A K774 N/A
M22520/2-08 9502-5 995-0001-604 601966-5 K13-1 615724
M81969/1-02 M81969/1-02 980-2000-426 91067-2 M24308/1-02 M81969/1-02
1. Insertion/extraction tools from ITT Cannon are all plastic; others are plastic with metal tip. 2. Non-Garmin part numbers shown are not maintained by Garmin and consequently are subject to change without notice. 3. Alternate contacts for 18 AWG wire: As an alternative to the Positronic contacts listed (and provided in the installation kit), the installer may use contacts made by ITT Cannon under P/N 031-1007-001. These contacts require the use of a different crimp tool positioner than shown in the table, with the part numbers as follows: Daniels P/N K250, Astro P/N 616245, or ITT Cannon P/N 980-0005-722. 4. All wires must be passed through the backshell before being assembled to connector. 5. In aircraft equipped with a dropping resistor for +28 VDC buss voltage, make sure the dropping resistor is bypassed.

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Figure 2-Pin D-Sub Connector Drawing
Table 2-Pin D-Sub Pin-Out Definitions
Not Used Do Not Connect Altitude A1 Altitude C2 Altitude A2 Altitude A4 Altitude C4 External Ident Altitude B1 Altitude C1 Altitude B2 Altitude B4 Ground Switched Power Output Aircraft Power (+11 to +33 VDC) External Standby External Suppression (Suppress I/O-GTX 320A) Altitude D4 Not Used Not Used Not Used Not Used 28 V Lighting 14 V Lighting Ground

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Check Existing Coax and Antenna Before Using a GTX 320/320A Adapter in an Existing Installation CAUTION
Before using a Narco or Bendix/King Adapter to install a GTX 320/320A into an existing installation, the RF coaxial cable, its connectors, and the antenna must be checked to ensure the following: There must be no corrosion or damage on the coax or its RF connectors that would adversely affect operation. The RF attenuation of the coax from the installation rack to the antenna must not exceed 1.5 dB at 1090 MHz. The antenna must not have corrosion, damage, or loose connections.
Installation Using Existing Narco AT 150 Installation Rack
The GTX 320 and GTX 320A can be used with an existing NARCO AT 150 Installation Rack by using the NARCO AT 150 Installation Adapter (P/N 011-00292-00). See figure B6 for the NARCO AT 150 Adapter assembly drawing.
GTX 320 units that are at Mod Level 1 must use the Mod Level 1 NARCO Installation Adapter. After Mod Level 1, the GTX 320 sits 0.17" (4.3 mm) closer to the instrument panel. Also, when installing the GTX 320 in an existing NARCO AT 150 rack (using the AT 150 Adapter) and when the aircraft has a bus voltage of +28 VDC, make sure the +28 VDC dropping resistor is bypassed. A. B. C. Slide the adapter into the rack installation until the jackscrew mates with its nut. Turn the jack screw with a 3/32" Allen wrench until the adapter is secure. Looking at the bottom of the transponder, make sure the front lobe of the locking mechanism is in a vertical position. This can be accomplished by using a 3/32" Allen wrench through the face plate. Slide the unit into the rack until the front lobe of the unit touches the rack. Guide pins on the back plate will help properly align the unit in the rack. Turn the Allen wrench clockwise until unit is secured in the rack. Continue turning until tight. Do not overtighten the screw. To remove the unit from the rack turn the 3/32" Allen wrench counterclockwise until it disengages from the rack.

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Installation Using Existing Bendix/King KT 76A/78A Installation Rack
The GTX 320 and GTX 320A can be used with an existing Bendix/King KT 76A/78A installation rack by using the KT 76A/78A Installation Adapter (P/N 011-00289-00). See figure B7 for the Bendix/King KT 76A/78A Adapter assembly drawing.
GTX 320 units that are at Mod Level 1 must use the Mod Level 1 Bendix/King KT 76A/78A Installation Adapter. After Mod Level 1, the GTX 320 sits 0.17" (4.3 mm) closer to the instrument panel. Also, when installing the GTX 320 in an existing Bendix/King KT 76A/78A rack (using the KT 76A/78A Adapter) and when the aircraft has a bus voltage of +28 VDC, make sure the +28 VDC dropping resistor is bypassed. A. Attach the KT 76A/78A installation adapter to the rear of the GTX 320 using the two captive screws on the adapter. Looking at the bottom of the transponder, make sure the front lobe of the locking mechanism is in a vertical position. This can be accomplished by using a 3/32" Allen wrench through the face plate. Slide the unit into the rack until the front lobe of the unit touches the rack. Guide pins on the back plate will help in the proper alignment of the unit in the rack. Turn the Allen wrench clockwise until unit is secured in the rack. Continue turning until tight. Do not overtighten the screw. To remove the unit from the rack, turn the 3/32" Allen wrench counterclockwise until it disengages from the rack.

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Blank Page

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POST INSTALLATION CONFIGURATION & CHECKOUT PROCEDURE Aircraft Station Licensing Requirements
The Telecommunications Act of 1996, effective February 8, 1996, provides the FCC discretion to eliminate radio station license requirements for aircraft and ships. At the present time, you do not need an individual license to operate the GTX 320/320A aboard your private aircraft in many circumstances. To find out the specific details on whether you are exempt from licensing, please see FCC Fact Sheet PR 5000 or contact the FCC at (800)-322-1117. If an aircraft license is required or desired, contact the FCC at (800)-322-1117 to request form 404, Application for Aircraft Radio Station License. The FCC also has a fax-on-demand service to provide forms by fax at (202)-418-0177. The GTX 320/320A owner accepts all responsibility for obtaining the proper licensing before using the transponder.

Operation NOTE

The coverage you can expect from the GTX 320/320A is limited to line of sight. Low altitude or aircraft antenna shielding by the aircraft itself may result in reduced range. Range can be improved by climbing to a higher altitude. It may be possible to minimize antenna shielding by locating the antenna where dead spots are only noticed during abnormal flight attitudes.
Figure 3-1. Transponder Front Panel (GTX 320 Shown)
The Transponder should be turned off before starting aircraft engine(s).

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3.2.1 Function Selection Switches
The function selector switch is a five position rotary switch. The five positions are: OFF Turns off all power to the GTX 320/320A.
SBY Turns the transponder on, but when in SBY the transponder will not reply to any interrogations from the ground radar system. ON Places the transponder in Mode A, the identification mode. In addition to the aircrafts identification code, the transponder will also reply to altitude interrogations (mode C) with signals that do not contain altitude information. ALT Places the transponder in Mode A and Mode C, the identification and altitude reporting modes to respond to ATC aircraft identification interrogations and altitude interrogations with standard pressure altitude (29.92 inches Hg.) received from an external altitude digital encoder. The ALT position may be used in aircraft that are not equipped with the optional altitude encoder, however, the only response will be discreet signals that do not contain altitude information.

Any time the function switch is in the ON or ALT position the transponder becomes an active part of the beacon system. Select ON or ALT as late as practical prior to takeoff and to OFF or SBY as soon as practical after completing landing roll unless the change to SBY has been accomplished previously at the request of ATC. TST Turning the switch to the TST position tests the reply indicator. The TST position is spring loaded and must be held momentarily. When released, it will automatically return to the ALT position.

3.2.2 Code Selection

The code selector consists of four, eight position switches that provide 4,096 active identification codes.
When making routine code changes, you should avoid inadvertent selection of codes 7500, 7600, or 7700 thereby causing momentary false alarms at automated ground facilities. For example when switching from code 2700 to code 7200, switch first to 2200 then 7200, NOT to 7700 and then 7200. This procedure applies to nondiscrete code 7500 and all discrete codes in the 7600 and 7700 series (i.e., 76007677, 7700-7777) which trigger special indicators in automated facilities. Only nondiscrete code 7500 will be decoded as the hijack code. An aircrafts transponder code (when available) is utilized to enhance the tracking capabilities of the ATC facility, therefore you should not turn the transponder to SBY when making routine code changes. See the Aeronautical Information Manual (AIM) for a detailed explanation of the identification codes.

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IDENT Button
On occasion, the controller will request SQUAWK IDENT. Respond by momentarily pressing and releasing the IDENT button. Pressing the IDENT button activates the Special Position Identification Pulse (SPI) for approximately 20 seconds identifying your transponder return from other aircraft on the controllers scope.

3.2.4 Reply Light

The reply light will blink each time the transponder replies to ground interrogation. The reply light also remains lit during the IDENT time interval.

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APPENDIX A CERTIFICATION DOCUMENTS

Continued Airworthiness

Other than for regulatory periodic functional checks, maintenance of the GTX 320/320A is on condition only. Refer to the GTX 320 and GTX 320A Maintenance Manuals. Periodic maintenance of the GTX 320/320A is not required. This section provides assistance to the installing agency in preparing Instructions for Continued Airworthiness (ICA) in response to Bulletin Number HBAW 98-18, Checklist for Instructions for Continued Airworthiness for Major Alterations Approved Under the Field Approval Process, effective 10/7/98. Aviation Authority approved installers are hereby granted permission to reference appropriate service instructions and excerpts from this Installation Manual to accomplish the Instructions for Continued Airworthiness. This permission does not construe suitability of the documents. It is the applicants responsibility to determine the suitability of the documents for the ICA. Following is a suggested ICA for a Garmin GTX 320/320A unit installation. Some of the checklist items do not apply, in which case they should be marked N/A (Not Applicable). Instructions For Continued Airworthiness, Garmin GTX 320/320A 1. Introduction [Aircraft that has been altered: Registration (N-) number, Make, Model and Serial Number] Content, Scope, Purpose and Arrangement: This document identifies the Instructions for Continued Airworthiness for the modification of the above aircraft by installation of a Garmin GTX 320/320A. Applicability: Applies to aircraft altered by installation of the Garmin GTX 320/320A. Definitions/Abbreviations: None, N/A. Precautions: None, N/A. Units of Measurement: None, N/A. Referenced Publications: Garmin GTX 320/320A Installation Manual, P/N 190-00133-01 Garmin GTX 320 Maintenance Manual, P/N 190-00133-02 Garmin GTX 320A Maintenance Manual, P/N 190-00133-08 Garmin STC # [applicable STC number for the specific model installed, refer to Appendix B of this manual]. Garmin GTX 320/320A Pilots Guide, P/N 190-00133-09. Distribution: This document should be a permanent aircraft record. 2. Description of the Alteration Installation of the Garmin GTX 320/320A, with interface to Encoding Altimeter or Blind Encoder. Refer to section 2.4 and Appendix B of this manual for interconnect information. Antenna installation, removal and replacement should be in accordance with applicable provisions of AC43.13-1B and 43.13-2A.

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3. Control, Operation Information
Refer to the GTX 320/320A Pilots Guide.

4. Servicing Information

5. Maintenance Instructions
Maintenance of the GTX 320/320A is on condition only. Periodic maintenance is not required. Refer to the GTX 320 and the 320A Series Maintenance Manuals.
6. Troubleshooting Information
Refer to the GTX 320 and the GTX 320A Maintenance Manuals.
7. Removal and Replacement Information
Refer to section 2.4 of this manual. If the unit is removed and reinstalled, a functional check of the equipment should be conducted in accordance with section 3.2 of this manual.

8. Diagrams

Refer to Appendix B of this manual.
9. Special Inspection Requirements N/A 10. Application of Protective Treatments N/A
11. Data: Relative to Structural Fasteners
Antenna installation, removal and replacement should be in accordance with applicable provisions of AC43.13-1A and 43.13-2A. Also, refer to section 2.3 of this manual.
12. Special Tools N/A 13. This Section is for Commuter Category Aircraft Only A. Electrical loads: Refer to section 1.3 of this manual.
B. Methods of balancing flight controls: N/A. C. Identification of primary and secondary structures: N/A. D. Special repair methods applicable to the airplane: Antenna installation, removal, and replacement should be in accordance with applicable provisions of AC43.13-1B and 43.13-2A.

14. Overhaul Period

No additional overhaul time limitations.
15. Airworthiness Limitation Section

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16. Revision
To revise this ICA, a letter must be submitted to the local FSDO with a copy of the revised FAA Form 337, and revised ICA. The FAA inspector accepts the change by signing Block 3 and including the following statement: The attached revised/new Instructions for Continued Airworthiness (date ______) for the above aircraft or component major alteration have been accepted by the FAA, superseding the Instructions for Continued Airworthiness (date ______).

17. Assistance

Flight Standards Inspectors have the resources to respond to questions regarding the ICA.
Implementation and Record Keeping
For major alterations performed in accordance with FAA field approval policy, the owner/operator operating under Part 91 is responsible for ensuring that the ICA is made part of the applicable section 91.409 inspection program for their aircraft. This is accomplished when a maintenance entry is made in the aircrafts maintenance record in accordance with section 43.9. This entry records the major alteration and identifies the original ICA location (e.g., Block 8 of FAA Form 337, dated ______) along with a statement that the ICA is now part of the aircrafts inspection/maintenance requirements.

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Environmental Qualification Form (GTX 320)
GTX 320 Airborne ATC Transponder Equipment TSO - C74c Class 1A

NOMENCLATURE:

TYPE/MODEL/PART NO.: 010-00135-00/10
MANUFACTURER'S SPECIFICATION AND/OR OTHER APPLICABLE SPECIFICATION: 004-00042-00 MANUFACTURER: ADDRESS: Garmin International 1200 E 151st St, Olathe, Kansas 66062
Table A-1 GTX 320 EQF Table

Conditions

Temperature and Altitude Low Temperature High Temperature In-Flight Loss of Cooling Altitude Decompression Overpressure Temperature Variation Humidity Shock Operational Crash Safety Vibration Explosion Waterproofness Fluids Susceptibility

RTCA DO160C Section

4.0 4.5.1 4.5.2. & 4.5.3 4.5.4 4.6.1 4.6.2 4.6.3 5.0 6.0 7.0 7.2 7.3 8.0 9.0 10.0 11.0
Description of Conducted Tests
Equipment tested to Categories A1 & D1 except as noted

Cooling air not required

Equipment tested to Category C Equipment tested to Category A Equipment tested according to DO-160C, Par. 7.2.1
Equipment tested without shock mounts to Categories B, M and N (Table 8-1) Equipment identified as Category X, no test required Equipment identified as Category X, no test required Equipment identified as Category X, no test required
Sand and Dust Fungus Salt Spray Magnetic Effect Power Input Voltage Spike
12.0 13.0 14.0 15.0 16.0 17.0
Equipment identified as Category X, no test required Equipment identified as Category X, no test required Equipment identified as Category X, no test required Equipment tested to Class Z Equipment tested to Category B Equipment tested to Category A

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Table A-1 GTX 320 EQF Table (continued)
Conditions Audio Frequency Susceptibility Induced Signal Susceptibility Radio Frequency Susceptibility Radio Frequency Emission Lightning Induce Transient Susceptibility Lightning Direct Effects Icing Other Tests Remarks- None
RTCA DO160C Section 18.0 19.0 20.0 21.0 22.0 23.0 24.0
Description of Conducted Tests Equipment tested to Category B Equipment tested to Category A Equipment tested to Category U Equipment tested to Category Z Equipment identified as Category XXXX, no test required Equipment identified as Category X, no test required Equipment identified as Category X, no test required

21.0 22.0 23.0 24.0 25.0

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APPENDIX B STC PERMISSION
Consistent with N8110.69 or Order 8110.4, Aviation Authority approved installations are hereby granted permission to use STC # SA00642WI data to modify aircraft.

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APPENDIX C ASSEMBLY AND INSTALLATION DRAWINGS

C.1 GENERAL

This section contains the following installation drawings:
C-1, GTX 320/320A Outline Drawing C-2, GTX 320/320A Connector/Rack Kit Assembly Drawing C-3, GTX 320/320A Recommended Panel Cutout Dimensions C-4, GTX 320/320A Interconnect Wiring Diagram C-5, Dual Transponder Interconnect Wiring Diagram C-6, Narco AT 150 Installation Adapter Assembly Drawing C-7, King KT 76A/78A Adapter Assembly Drawing

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Figure C-1 GTX 320/320A OUTLINE DRAWING
Page C-3 (Page C-4 blank) Rev M
011-00338-00 CONNECTOR/RACK KIT
ITEM 211-63234-12 212-20014-00 232-00013-01 330-00220-25 330-00184-25 330-00198-00 336-00022-00 336-00023-00 312-00005-05 115-00285-00 SEE NOTE NOT SHOWN NOT SHOWN NOT SHOWN SEE NOTE 125-00032-02 211-60234-06 125-00046-00 234-10002-00 330-00326-00

PART NUMBER

DESCRIPTION SCREW, 4-40X.75, FLHP, SS/P WSHR, FLAT, NON-STD, SS SNAP RING, EXT, 7/16 BACKSHELL, D-SUB, METAL, 25 POS. CONN., D-SUB, MIL CRP, SCKT, 25 CONN, BNC, MALE BLINDMATE CONT. SCKT, MIL CRP, SIZE 20 CONT, SCKT, MIL CRP, SIZE 20-18 TUBING, HT SHRINK INSTALL RACK BACK PLATE SCREW, 4-40X.187, PHP, SS/P NUT PLATE, D-SUB, 25 POSITION SPRING WASHER RF ADAPTER

SEE NOTE

2.3IN.

2 THESE HOLES NOT USED

NOTE: KIT WILL INCLUDE EITHER ITEM 6 OR ITEM 12. REFER TO SECTION 2 FOR ADDITIONAL INFORMATION.
Figure C-2 GTX 320/320A CONNECTOR/RACK KIT ASSEMBLY DRAWING
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Figure C-3 GTX 320/320A RECOMMENDED PANEL CUTOUT DIMENSIONS
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Figure C-4 GTX 320/320A INTERCONNECT WIRING DIAGRAM
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Figure C-5 GTX 320/320A DUAL TRANSPONDER INTERCONNECT WIRING DIAGRAM
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Figure C-6 NARCO AT 150 INSTALLATION ADAPTER ASSEMBLY DRAWING
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Figure C-7 KING KT 76A/78A ADAPTER ASSEMBLY DRAWING
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GTX 320A

Mode A/C Transponder

pilots guide

320A NewGuide.indd

09/29/00, 3:10 PM

2000 GARMIN Corporation GARMIN International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, U.S.A. Tel. 913/397.8200 or 800/800.1020 Fax 913/397.8282 GARMIN (Europe) Ltd. Unit 5, The Quadrangle, Abbey Park Industrial Estate, Romsey, SO51 9AQ, U.K. Tel. 44/1794.519944 Fax 44/1794.519222 GARMIN Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan Tel. 886/2.2642.9199 Fax 886/2.2642.9099 Website Address: www.garmin.com 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 prior written consent of GARMIN Corporation. GARMIN Corporation hereby grants permission to download a single copy of this manual onto a hard drive or other electronic storage medium to be viewed for personal use, provided that such electronic or printed copy of this manual contains the complete text of this copyright notice and provided further that any unauthorized commercial distribution of this manual is strictly prohibited. Information in this manual is subject to change without notice. GARMIN Corporation reserves the right to change or improve its products and to make changes in the content without obligation to notify any person or organization of such changes. Visit the GARMIN website (www.garmin.com) for current updates and supplemental information concerning the use and operation of this and other GARMIN products. GARMIN is a registered trademark of GARMIN Corporation and may not be used without the express permission of GARMIN Corporation.

October 2000

Part Number 190-00133-09 Rev. A

Printed in USA

10/02/00, 4:31 PM

Limited Warranty

GARMIN Corporation warrants this product to be free from defects in materials and workmanship for one year from the date of purchase. GARMIN will, at its sole option, repair or replace any components which fail in normal use. Such repairs or replacement will be made at no charge to the customer for parts or labor. The customer is, however, responsible for any transportation costs. This warranty does not cover failures due to abuse, misuse, accident or unauthorized alteration or repairs. THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED, INCLUDING ANY LIABILITY ARISING UNDER WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM STATE TO STATE. IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT. SOME STATES DO NOT ALLOW THE EXCLUSIONS OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS MAY NOT APPLY TO YOU. To obtain warranty service, call the GARMIN Customer Service department (913/397.8200) for a returned merchandise tracking number. The unit should be securely packaged with the tracking number clearly marked on the outside of the package, and sent freight prepaid and insured to a GARMIN warranty service station. A copy of the original sales receipt is required as the proof of purchase for warranty repairs. GARMIN retains the exclusive right to repair or replace the unit or software or offer a full refund of the purchase price at its sole discretion. SUCH REMEDY SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.

NOTE: The GTX 320A owner accepts all responsibility for obtaining the proper licensing before using the transponder. NOTE: The coverage you can expect from the GTX 320A is limited to line of sight. Low altitude or aircraft antenna shielding by the aircraft itself may result in reduced range. Range can be improved by climbing to a higher altitude. It may be possible to minimize antenna shielding by locating the antenna where dead spots are only noticed during abnormal ight attitudes. CAUTION: The GTX 320A should be turned off before starting or shutting down aircraft engine(s).

Ident Button

Reply Light

Code Selection Knobs

Function Selection Knob
Function Selector Switch:
The function selector switch is a ve position rotary switch. The ve positions are:
OFF-Turns off all power to the GTX 320A (the unit should be turned off before starting aircraft engine(s). SBY-Turns the transponder on, but when in SBY the unit will not reply to any interrogations. ON-The transponder transmits the aircrafts identication code (Mode A) but does not include altitude information. ALT- The transponder transmits the aircrafts identication code, in Mode A and pressure altitude (29.92 inches Hg) information in Mode C provided the aircraft is equipped with an optional altitude encoder. The unit is normally operated in the ALT position at all times unless otherwise directed by ATC. TST-Moving the switch to the TST position tests the reply light. The function selector is spring loaded and must be held in TST position. When released, it automatically returns to the ALT position. Any time the function switch is in the ON or ALT position the transponder becomes an active part of the Air Trafc Control Radar Beacon System (ATCRBS). The transponder also responds to interrogations from TCAS equipped aircraft.

Code Selector

The code selector consists of four, eight-position switches that provide 4,096 active identication codes. The code selected should be either a VFR code or a code assigned by ATC. Regulations require that aircraft equipped with a transponder must operate the transponder, including Mode C equipment unless otherwise directed by ATC. When making routine code changes, you should avoid inadvertent selection of codes 7500, 7600, or 7700 causing momentary false alarms at ground facilities. For example when switching from code 2700 to code 7200, switch rst to 2200 then 7200, NOT to 7700 and then 7200. This procedure applies to nondiscrete code 7500 and all discrete codes in the 7600 and 7700 series (i.e., 7600 to 7677, 7700 to 7777) which trigger special indicators in automated facilities. Only nondiscrete code 7500 will be decoded as the hijack code. An aircrafts transponder code is utilized for ATC tracking capability, therefore you should not turn the GTX 320A to SBY when making routine code changes.

Important Codes

1200-The United States VFR Code for any altitude. 7600-Loss of Communications. 7500-Hijacking (Never assigned by ATC without prior notication of the pilot that the aircraft is subject to unlawful interference). 7700-Emergency. 0000-Military use. Never squawk this Code. See the Aeronautical Information Manual (AIM) for an explanation and uses of identication codes.

IDENT Button

On occasion, a controller will request SQUAWK IDENT to identify your transponder return from other aircraft. Respond by momentarily pressing the IDENT button, activating the Special Position Identication for approximately 20 seconds.
The reply light will blink each time the transponder replies to an interrogation. The reply light remains illuminated during the IDENT time interval and during TST function.
GTX 320A TRANSPONDER SPECIFICATIONS
TSO Compliance: Temperature Range Installed weight with rack & connectors Physical dimensions: Bezel height Bezel width Depth behind panel incl. connectors Power Requirements Humidity Altitude Transmitter Frequency Transmitter Power Receiver Frequency Receiver Sensitivity Mode A Capability Mode C Capability External Suppression 1.63 in. (41 mm) 6.25 in. (159 mm) 8.76 in. (223 mm) 11.0 to 33.0 Vdc; Max Power Input: 12 Watts @ 500 prf 95% @ +55C for 16 Hours; 85% @ +38C for 32 Hours 50,000 Feet 1090 MHz 200 Watts Nominal 1030 MHz -74dBm Nominal for 90% replies 4096 Identication Codes 100 Foot Increments from -1000 to 63,000 feet Input - Low 0.5V; High 8V Output 18V Pulse TSO C74c Class 1A -20C to +55C (Continuous Operation) 2.9 lbs. (1.3 kg)
2000 GARMIN Corporation GARMIN International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, U.S.A. GARMIN (Europe) Ltd. Unit 5, The Quadrangle, Abbey Park Industrial Estate, Romsey, SO51 9AQ, U.K. GARMIN Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan www.garmin.com Part Number 190-00133-09 Rev. A