Garmin GDL 90 User manual

GDL 90 UAT Data Link Sensor
Installation Manual
October 2006
560-1049-02 Rev. B

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GDL 90 Installation Manual 560-1049-02 Rev. B i
History of Revisions
Revision Date Description
-00 -- 3/17/04 Initial release
-00 A 4/07/04 Update environmental categories (1.3.3, A.1), FCC waiver (1.4.3), APM p/n (Table 1-3). Add
missing lines (Figure 2-1), APM weight (Table 2-6), APM environmental qualification form
(A.2).
-00 B 4/30/04 Remove “STC Pending watermark”. Clarify output of data (1.2). Add transmitter caution
(1.3.7.2, 2.1, 2.5.2, 2.6.2, 2.8.1, 3.2.2, 4.). Add washer to install kit (Table 1-3). Limit APM
wire length to 4 inches, clarify APM tests, update lightning categories (2.5.2, 2.8.2, A.1, A.2, Fig
C-1). Add exploded-view diagrams (Fig. 2-4, 2-5). Correct MX20 manual refs (4.2.2, 4.3.1.2.2).
-01 -- 11/2/04 Extensive updates for GDL 90 Version 2.0 capabilities.
-01 A 11/10/04 Added text for Playaudio command.
-02 Rev 1 12/29/05 Experimental release for Ver 2.1 review.
-02 Rev A 4/28/06 Extensive updates for GDL 90 Version 2.1 capabilities.
-02 Rev B 10/05/06 Updates as follows:
Throughout: Added GMX 200 references to most places that discuss the MX20.
§1.3.4: Update GPS performance specifications.
§1.3.7.1: Update the list of approved GPS antennas.
§1.4.3: Added list of TSO deviations.
§2.6.1: Clarify the required GPS cable loss, and that the GDL 90 is not compatible with
SATCOM equipment. Clarified note regarding use of existing GPS antennas.
§2.10: Added recommended circuit breaker size and placard information.
§3.1: Updated the operational limitations.
§3.2: Update the description of the limitations regarding single-point squawk code entry.
§3.2.2: Add an instruction to check the correct box for GDL 90 control in the FMS.
§3.2.4: Updated the list of approved GPS antennas.
Table 4-3: Update RS-422 port configuration info for use with GMX 200.
§4.2.3: Clarify the use of the “CAPSTONE feature”.
§4.3.1.1: Removed checkout procedure for SATCOM equipment.
Appendix A.2 & A.3: Added a Note on reduced helicopter vibration levels to the environmental
qualification form.
Fig C-1: Updated wiring diagram (Note 3) for recommend GPS cable losses and GMX 200
information.
Ordering Information
To receive additional copies of GDL 90 publications, order the following part numbers:
GDL 90 Installation Manual* 560-1049-( )
A-41 UAT Antenna Installation Guide* 560-0215-( )
A-40 UAT Antenna Installation Guide* 560-0253-( )
A-33 GPS Antenna Installation Guide* 560-0949-( )
A-34 GPS Antenna Installation Guide* 560-5047-( )
GDL 90 Product CD 140-0063-( )
GDL 90 Helicopter Installation Supplement* 561-0290-( )
*These documents, and others relating to the GDL 90 installation, STC certification, and continued
airworthiness/maintenance, are included in electronic form in the GDL 90 UAT Sensor Product CD, part
number 140-0063-( ).

ii 560-1049-02 Rev. B GDL 90 Installation Manual
List of Effective Pages
Page Rev Page Rev Page Rev Page Rev Page Rev
Cover B 2-25 B B-1 A
Copyright B 2-26 A B-2 A
i B B-3 A
ii B 3-1 B B-4 A
iii B 3-2 B B-5 A
iv B 3-3 B B-6 A
v B 3-4 A
vi B C-1 A
4-1 A C-2 A
1-1 A 4-2 A C-3 A
1-2 B 4-3 A C-4 A
1-3 A 4-4 A C-5 A
1-4 B 4-5 A C-6 A
1-5 B 4-6 A
1-6 B 4-7 A D-1 A
1-7 B 4-8 A D-2 A
1-8 B 4-9 B D-3 A
1-9 A 4-10 B
1-10 A 4-11 B
4-12 A
2-1 A 4-13 B
2-2 A 4-14 A
2-3 A 4-15 A
2-4 A 4-16 A
2-5 A 4-17 A
2-6 A 4-18 B
2-7 A 4-19 B
2-8 B 4-20 A
2-9 B
2-10 A 5-1 A
2-11 A 5-2 A
2-12 A 5-3 A
2-13 A 5-4 B
2-14 A 5-5 A
2-15 A 5-6 A
2-16 A
2-17 A 6-1 A
2-18 A 6-2 A
2-19 A
2-20 B A-1 A
2-21 A A-2 B
2-22 A A-3 B
2-23 A A-4 A
2-24 A

Table of Contents
GDL 90 Installation Manual 560-1049-02 Rev. B iii
Table of Contents
1GENERAL INFORMATION ........................................................................................................................1-1
1.1 ABOUT THIS MANUAL ..................................................................................................................................1-1
1.1.1 MANUAL ORGANIZATION .........................................................................................................................1-1
1.1.2 SCOPE ......................................................................................................................................................1-1
1.1.3 REFERENCE DOCUMENTS.........................................................................................................................1-1
1.2 EQUIPMENT DESCRIPTION .............................................................................................................................1-2
1.2.1 FEATURES ................................................................................................................................................1-2
1.2.2 SYSTEM INTERFACES ...............................................................................................................................1-2
1.3 SPECIFICATIONS ............................................................................................................................................1-4
1.3.1 ELECTRICAL .............................................................................................................................................1-4
1.3.2 PHYSICAL .................................................................................................................................................1-4
1.3.3 ENVIRONMENTAL .....................................................................................................................................1-4
1.3.4 GPS/WAAS RECEIVER PERFORMANCE ...................................................................................................1-4
1.3.5 UAT PERFORMANCE................................................................................................................................1-5
1.3.6 AVIONICS INTERFACES .............................................................................................................................1-5
1.3.7 ANTENNA REQUIREMENTS .......................................................................................................................1-6
1.4 REGULATORY COMPLIANCE..........................................................................................................................1-8
1.4.1 TSO AND ADVISORY CIRCULAR REFERENCES .........................................................................................1-8
1.4.2 TSO AUTHORIZATION ..............................................................................................................................1-8
1.4.3 TSO DEVIATIONS.....................................................................................................................................1-8
1.4.4 FCC GRANT OF EQUIPMENT AUTHORIZATION..........................................................................................1-8
1.4.5 GDL 90 STC AUTHORIZATION.................................................................................................................1-8
1.5 UNPACKING THE EQUIPMENT ........................................................................................................................1-9
1.6 PACKAGE CONTENTS ....................................................................................................................................1-9
1.7 DEFINITIONS &ACRONYMS ........................................................................................................................1-10
2INSTALLATION .................................................................................................................................................2-1
2.1 PRE-INSTALLATION INFORMATION................................................................................................................2-1
2.2 INSTALLATION OVERVIEW ............................................................................................................................2-1
2.3 MATERIALS NOT SUPPLIED ...........................................................................................................................2-1
2.3.1 MATERIALS REQUIRED BUT NOT SUPPLIED .............................................................................................2-1
2.4 SPECIAL TOOLS REQUIRED............................................................................................................................2-2
2.5 EQUIPMENT MOUNTING ................................................................................................................................2-2
2.5.1 CABLING AND WIRING..............................................................................................................................2-2
2.5.2 MOUNTING TRAY INSTALLATION .............................................................................................................2-2
2.5.3 UNIT INSERTION &REMOVAL ..................................................................................................................2-7
2.6 ANTENNA INSTALLATION AND CONNECTIONS...............................................................................................2-8
2.6.1 GPS ANTENNA.........................................................................................................................................2-8
2.6.2 UAT ANTENNAS ....................................................................................................................................2-10
2.7 ELECTRICAL CONNECTIONS ........................................................................................................................2-11
2.7.1 INTERFACE CONNECTOR DEFINITION .....................................................................................................2-12
2.8 FUNCTIONAL DESCRIPTIONS .......................................................................................................................2-15
2.8.1 POWER ...................................................................................................................................................2-15
2.8.2 MICRO AIRCRAFT PERSONALITY MODULE (APM) .................................................................................2-15
2.8.3 STATUS LEDS........................................................................................................................................2-16
2.8.4 DISCRETE OUTPUT .................................................................................................................................2-17
2.8.5 DISCRETE INPUTS...................................................................................................................................2-18
2.8.6 SERIAL INTERFACES ...............................................................................................................................2-19
2.8.7 AUDIO OUTPUT ......................................................................................................................................2-22
2.8.8 SUPPRESSION OUTPUT............................................................................................................................2-22
2.8.9 1PPS TIME MARK INPUT/OUTPUT.........................................................................................................2-22
2.9 WEIGHT AND BALANCE...............................................................................................................................2-23
2.10 ELECTRICAL LOAD ANALYSIS .....................................................................................................................2-25
3LIMITATIONS....................................................................................................................................................3-1

Table of Contents
iv 560-1049-02 Rev. B GDL 90 Installation Manual
3.1 OPERATION ...................................................................................................................................................3-1
3.2 INSTALLATION...............................................................................................................................................3-1
3.2.1 SURVEILLANCE SERVICES ........................................................................................................................3-1
3.2.2 FLIGHT MANUAL SUPPLEMENT ................................................................................................................3-2
3.2.3 TCAS INTERFACE ....................................................................................................................................3-2
3.2.4 GPS ANTENNA.........................................................................................................................................3-2
3.2.5 UAT ANTENNA ........................................................................................................................................3-2
3.2.6 ANTENNA INSTALLATION –GENERAL ......................................................................................................3-3
3.2.7 EQUIPMENT INTERFACED TO THE GDL 90................................................................................................3-3
3.2.8 TRAFFIC DISPLAY.....................................................................................................................................3-3
3.2.9 PRESERVATION OF PREVIOUS SYSTEMS ...................................................................................................3-3
4POST INSTALLATION CONFIGURATION &CHECKOUT PROCEDURES............................................................4-1
4.1 MOUNTING AND WIRING CHECK...................................................................................................................4-1
4.2 EQUIPMENT SETUP AND CONFIGURATION .....................................................................................................4-1
4.2.1 HOW TO USE THE GDL 90 MAINTENANCE PORT WITH HYPERTERMINAL ................................................4-1
4.2.2 MAINTENANCE COMMANDS .....................................................................................................................4-2
4.2.3 MICRO APM INITIALIZATION PROCEDURE ...............................................................................................4-9
4.2.4 MICRO APM CONFIGURATION WORKSHEET ..........................................................................................4-13
4.2.5 OTHER EQUIPMENT SETUP .....................................................................................................................4-13
4.3 EQUIPMENT OPERATIONAL/FUNCTIONAL TEST ...........................................................................................4-17
4.3.1 SYSTEM CHECKOUT -GROUND CHECKS ................................................................................................4-17
5TROUBLESHOOTING.........................................................................................................................................5-1
5.1 TROUBLESHOOTING PROCEDURE ..................................................................................................................5-1
5.2 COLLECTING ADDITIONAL INFORMATION......................................................................................................5-2
5.2.1 MESSAGES FOR SERVICE COMMAND........................................................................................................5-2
5.2.2 MESSAGES FOR EXTERNAL COMMAND ....................................................................................................5-3
5.3 HOW TO VIEW THE GDL 90 INTERNAL GPS STATUS ON AN MX20 (IF EQUIPPED)........................................5-4
5.4 CONTACTING THE FACTORY FOR ASSISTANCE ..............................................................................................5-4
6PERIODIC MAINTENANCE ................................................................................................................................6-1
6.1 EQUIPMENT CALIBRATION ............................................................................................................................6-1
6.2 CLEANING .....................................................................................................................................................6-1
6.3 BATTERY REPLACEMENT ..............................................................................................................................6-1
6.4 ALTITUDE SOURCE........................................................................................................................................6-1
6.5 AUDIO ALERTS..............................................................................................................................................6-1
APPENDIX A -CERTIFICATION DATA....................................................................................................................... 1
A.1 GDL 90 ENVIRONMENTAL QUALIFICATION -FIXED-WING .............................................................................. 1
A.2 GDL 90 ENVIRONMENTAL QUALIFICATION -ROTORCRAFT ............................................................................. 2
A.3 MICRO APM ENVIRONMENTAL QUALIFICATION .............................................................................................. 3
APPENDIX B -TROUBLESHOOTING FLOWCHARTS .................................................................................................. 1
APPENDIX C -INTERCONNECT DIAGRAMS .............................................................................................................. 1
APPENDIX D -CONSTRUCTION &VALIDATION OF STRUCTURES ........................................................................... 1
List of Tables
TABLE 1-1. GARMIN UAT ANTENNAS.......................................................................................................1-7
TABLE 1-2. TSO AUTHORIZATION.............................................................................................................1-8
TABLE 1-3. PACKAGE CONTENTS ..............................................................................................................1-9
TABLE 1-4. INSTALLATION KIT CONTENTS (PN 424-6081-100) .............................................................1-10
TABLE 1-5. OPTIONAL PARTS ..................................................................................................................1-10
TABLE 2-1. CRIMP TOOL FOR P/N 245-0027 .............................................................................................2-2
TABLE 2-2. INTERFACE CONNECTORS .....................................................................................................2-11
TABLE 2-3. CRIMP CONTACT SPECIFICATIONS........................................................................................2-11

Table of Contents
GDL 90 Installation Manual 560-1049-02 Rev. B v
TABLE 2-4. MAIN SYSTEM CONNECTOR PIN-OUT (P1)...........................................................................2-13
TABLE 2-5. I/O CONNECTOR PIN-OUT (P2) .............................................................................................2-14
TABLE 2-6. UNIT WEIGHTS......................................................................................................................2-23
TABLE 2-7. UNIT POWER LOADS .............................................................................................................2-25
TABLE 2-8: CIRCUIT BREAKER SIZE &PLACARD.....................................................................................2-25
TABLE 4-1. MAINTENANCE MODE COMMANDS ........................................................................................4-2
TABLE 4-2. DISCRETE DISPLAY FORMAT ...................................................................................................4-4
TABLE 4-3. DATA ITEMS FOR APM INITIALIZATION .................................................................................4-9
TABLE 4-4. APM WORKSHEET ................................................................................................................4-15
TABLE 4-5. GDL 90 POST-INSTALLATION CHECKOUT LOG ....................................................................4-20
TABLE 5-1. TROUBLESHOOTING GUIDE.....................................................................................................5-1
TABLE D-1. STATIC TEST LOAD ...............................................................................................................D-1
List of Illustrations
FIGURE 1-1. TYPICAL GDL 90 SYSTEM DIAGRAM ....................................................................................1-3
FIGURE 2-1. SINGLE ENGINE AIRCRAFT GDL 90 MOUNTING LOCATIONS................................................2-3
FIGURE 2-2. MULTI-ENGINE AIRCRAFT GDL 90 MOUNTING LOCATIONS ................................................2-4
FIGURE 2-3. GDL 90 MOUNTING TRAY AND DIMENSIONS .......................................................................2-5
FIGURE 2-4. GDL 90 TRAY AND CONNECTORS .........................................................................................2-6
FIGURE 2-5. GDL 90 TRAY AND OPTIONAL COVER ..................................................................................2-7
FIGURE 2-6. ANTENNA PLACEMENT ..........................................................................................................2-8
FIGURE 2-7. RIGHT ANGLE COAX CONNECTOR ASSEMBLY ....................................................................2-10
FIGURE 2-8. REAR CONNECTOR LAYOUT ................................................................................................2-12
FIGURE 2-9. 15-PIN CONNECTOR –P1.....................................................................................................2-13
FIGURE 2-10. 37-PIN CONNECTOR –P2 ...................................................................................................2-14
FIGURE 2-11. GDL 90 CENTER OF GRAVITY ...........................................................................................2-24
FIGURE C-1. INTERCONNECT DIAGRAM FOR INSTALLATION W/MX20 MFD..............................................3
FIGURE C-2. INTERCONNECT DIAGRAM FOR CONTROL PANEL INSTALLATIONS..........................................4
FIGURE C-3. INTERCONNECT DIAGRAM FOR GARMIN DISPLAYS.................................................................5
FIGURE D-1. UPWARD STATIC LOAD TEST...............................................................................................D-2
FIGURE D-2. FORWARD STATIC LOAD TEST.............................................................................................D-2

Table of Contents
vi 560-1049-02 Rev. B GDL 90 Installation Manual
Notes

General Information
GDL 90 Installation Manual 560-1049-02 Rev. B 1-1
1 GENERAL INFORMATION
1.1 About This Manual
This manual describes the installation and checkout procedures for the GDL 90 UAT Data Link Sensor.
It is intended for use by persons certified by the Federal Aviation Administration (FAA) to install
avionics devices.
1.1.1 Manual Organization
Section 1 Provides General Information about the GDL 90 unit. TSO certification
information is also included in this section.
Section 2 Includes Installation procedures.
Section 3 Includes Limitations for the equipment and installation.
Section 4 Includes Post-Installation Configuration and Checkout procedures.
Section 5 Includes Troubleshooting information.
Section 6 Includes Periodic Maintenance requirements.
Appendix A Includes Certification Data.
Appendix B Includes Troubleshooting Flowcharts.
Appendix C Includes Interconnect Diagrams.
Appendix D Includes Construction & Validation of structures.
1.1.2 Scope
The information in this manual is STC approved. Only the equipment interfaces covered in this manual
are within the scope of this STC. Other equipment may be suitable for use with the GDL 90, but use of
such equipment is beyond the scope of this STC – additional FAA approval may be required if equipment
not covered in this manual is used to interface to the GDL 90.
This document describes the GDL 90 operating with software Version 2.1 and later. Version 2.1
supports all previous GDL 90 features.
Antenna installation in the pressure vessel of pressurized aircraft is also beyond the scope of the GDL 90
STC. Additional manufacturer's data may be necessary and FAA approval may be required to cover the
installation of the antenna.
Refer to Section 3 Limitations for additional information.
1.1.3 Reference Documents
•Garmin AT Document 560-1058-00 “GDL 90 Data Interface Specification”
This document (also known as the “Public ICD”) describes the Traffic Alert and Pass-through data
interfaces to a cockpit display, and the Control Panel interface.

General Information
1-2 560-1049-02 Rev. B GDL 90 Installation Manual
1.2 Equipment Description
The Garmin GDL 90 is a remote-mounted product that contains a GPS/WAAS receiver and a Universal
Access Transceiver. The GDL 90 will transmit ownship data via the UAT data link. It will receive data
from other UAT-equipped aircraft, as well as FIS-B weather – the received data may be output to an
appropriate display.
1.2.1 Features
The features of the GDL 90 UAT Data Link Sensor include:
•10-40 VDC Power Capability
•978 MHz Universal Access Transceiver data link radio designed to support ADS-B, TIS-B and
FIS-B airborne and ground applications
•GPS/WAAS receiver for state-of-the-art fast, accurate ADS-B position data (15-channel, 3
WAAS decoders, 5 Hz update of position, time, and velocity)
•Interface to Altitude Encoder via RS-232 or ARINC 429 buses
•Interface to a Control Panel or Transponder via RS-232 bus
•Interface to Garmin MX20 and GMX 200 Multi-function Displays, the Garmin GNS 400- and
500-series displays, and other display units that support the Garmin or Public ICD standard.
1.2.2 System Interfaces
The interfaces for a typical GDL 90 are shown in Figure 1-1. The available interfaces are further
described in the following sections.

General Information
GDL 90 Installation Manual 560-1049-02 Rev. B 1-3
Top UAT Antenna
Bottom UAT Antenna
GPS Antenna
GDL 90
Control Panel / Transponder
(optional)
MFD
Altitude Encoder
Maintenance
Port
Audio
Figure 1-1. Typical GDL 90 System Diagram
1.2.2.1 Multi-Function Display
The GDL 90 is capable of providing in-cockpit displays with traffic and optionally weather information.
The ability to display weather information depends on the specific display selected.
If the display is an MX20, it must use software Version 5.3 or later.
1.2.2.2 Altitude Encoder
The GDL 90 can connect to an altitude encoder to obtain pressure altitude data via an RS-232 or ARINC
429 bus.
1.2.2.3 Control Panel
The GDL 90 can connect to an optional Control Panel unit (such as the GSL 71), or certain models of
transponder via an RS-232 bus.
1.2.2.4 Annunciator Outputs and Switch Inputs
The GDL 90 can drive one external annunciator lamp and receive inputs from various switches to control
its operation.
1.2.2.5 Maintenance Interface
The GDL 90 has an RS-232 communication port that is used to configure and check the status of the
GDL 90 system.
1.2.2.6 Audio Alert
The GDL 90 has one 500 Ωaudio output that can be connected to an audio panel to provide audible
messages to the pilot.

General Information
1-4 560-1049-02 Rev. B GDL 90 Installation Manual
1.3 Specifications
This section includes detailed electrical, physical, environmental and performance specifications for the
GDL 90.
1.3.1 Electrical
Input voltage.................................................. 10 - 40 VDC
Input current (typical) ................................... 1.5 A at 14 VDC
750 mA at 28 VDC
1.3.2 Physical
Height............................................................ 7.42 inches (18.84 cm)
Width............................................................. 3.54 inches (8.97 cm)
Depth............................................................. 12.64 inches (32.11 cm)
Weight........................................................... 6.4 lb (2.9 kg) with mounting tray
1.2 lb (0.54 kg) mounting tray only
1.3.3 Environmental
The GDL 90 is designed and tested to meet appropriate categories as shown in the Environmental
Qualification Form included in Appendix A.
Operating temperature................................... -20°C to +55°C
Storage temperature ...................................... -55°C to +85°C
Temperature variation ................................... 5°C per minute
Humidity ....................................................... 95% at 65°C
Maximum continuous altitude ...................... 55,000 feet
Decompression.............................................. 55,000 feet
External Cooling ...........................................Not required with internal fans operational and
vents unobstructed
Water-resistant .............................................. With vertical mounting and optional cover
1.3.4 GPS/WAAS Receiver Performance
TSO Compliance........................................... TSO-C145a (RTCA/DO-229C)
Number of Channels .....................................15 (12 GPS and 3 GPS/WAAS/SBAS)
Frequency...................................................... 1575.42 MHz L1, C/A code
Sensitivity (Acquisition, no interference)..... -134.5 dBm GPS
-134.5 dBm WAAS
Position Accuracy (with WAAS).................. 1.25 meter RMS horizontal, 2 meter vertical
Velocity......................................................... 1000 knots maximum (above 60,000 ft)
TTFF (time to first fix) .................................1:45 min. typical with current almanac, position, and
time
Reacquisition................................................. 10 seconds typical
Position Update Interval................................ 0.2 sec (5 Hz)

General Information
GDL 90 Installation Manual 560-1049-02 Rev. B 1-5
1 pps (Pulse Per Second)............................... ±275 nsec of UTC second
Datum............................................................ WGS-84
Antenna Power Supply.................................. 35 mA typical, 40 mA max at 4.7 VDC
1.3.5 UAT Performance
TSO Compliance........................................... TSO-C154 (RTCA/DO-282)
Frequency...................................................... 978.00 MHz
Transmit Power ............................................. 50 W (+47 dBm)
Frequency Tolerance..................................... +/- 20 PPM
Modulation .................................................... Continuous Phase FSK, h = 0.6, Raised Cosine
shaping, a = 0.5
Data Rate....................................................... 1.04 Mbps
99% Power Bandwidth.................................. 1.3 MHz
60 dB Bandwidth........................................... 3.3 MHz (estimated)
Receiver Sensitivity ...................................... -96 dBm for 90% MSR
1.3.6 Avionics Interfaces
Annunciator Outputs ..................................... Open collector output capable of sinking up to 400
mA for turning ON annunciator lamp
Display .......................................................... RS-422 asynchronous serial
RS-232 asynchronous serial
ARINC 429 traffic interface
Altitude Encoder ........................................... RS-232 asynchronous serial
ARINC 429 ADC/AHRS source
Control Panel................................................. RS-232 asynchronous serial
External Position Input.................................. From ARINC 743A source

General Information
1-6 560-1049-02 Rev. B GDL 90 Installation Manual
1.3.7 Antenna Requirements
1.3.7.1 GPS Antennas
The GDL 90 may be installed with the Garmin AT A-33 and A-34 GPS antennas. The following table
summarizes the antenna identification.
Model/Description Mount Style Manufacturer Part
Number
Order
Number
Aero Antenna 575-9 N/A
A-33, GPS WAAS
Antenna Screw Mount Garmin AT 590-1104 N/A
Aero Antenna 575-93 013-00113-00
A-34, GPS WAAS
Antenna
Screw Mount,
Teardrop Footprint Garmin AT 590-1112 013-00113-00
1.3.7.1.1 A-33 (590-1104)
Early production runs of PN 590-1104 were marked with TSO-C129a. This antenna was re-qualified to
TSO-C144 with no changes to the antenna. P/N 590-1104 antennas marked with TSO-C129a
identification are identical to those marked with TSO-C144.
Applicable TSO.......................................................... TSO-C144 (RTCA/DO-228 with Change No. 1)
Frequency...................................................... 1575 MHz
Polarization ................................................... Right Hand Circular
Axial Ratio .................................................... 3 dB Max at bore site
Radiation Coverage....................................... Elevation Angle Minimum Gain
>15º -2.0 dBic
10º -3.0 dBic
5º -4.5 dBic
0º -7.5 dBic
Finish............................................................. Polyurethane Enamel
Weight........................................................... 3.9 oz. (0.11 kg)
Height............................................................ 0.61 inches (1.55 cm)
Operating Temperature .............................................. -55°C to +85°C
Operating Altitude...................................................... 55,000 feet (16,764m) max.
Amplifier:
Gain ........................................................ 26.5 dB ±2 dB
Noise Figure ........................................... 2.5 dB Max
Impedance............................................... 50 ohms
VSWR (Dry)........................................... < 1.5:1
VSWR (Rain) ......................................... < 2.0:1
Band Rejection ....................................... 35 dB

General Information
GDL 90 Installation Manual 560-1049-02 Rev. B 1-7
Power Handling ...................................... 1 Watt
Voltage ................................................... 5 VDC ±10%
Current.................................................... 35 mA nominal, 40 mA max.
L1 Filter Bandwidth ............................... 1575 ±20 MHz (3 dB)
+110, -210 MHz (60dB)
Group Delay (3dB bandwidth) ............... 27 ±10 nanosecond
Pass Band Ripple (3dB bandwidth) …….0.2 dB max
1.3.7.2 A-34 (590-1112)
The Garmin AT A-34 is an acceptable antenna. For specifications of the A-34 antenna, refer to the latest
revision of P/N 560-5047-( ).
1.3.7.3 UAT Antenna
The GDL 90 requires a UHF antenna meeting the following specifications:
•Standard 50Ωvertically polarized antenna with a VSWR < 1.7:1 at 978 MHz
•TSO-C66, C74, C112 or C154 antennas that also meet the VSWR specification.
Table 1-1. Garmin UAT Antennas
Antenna Model and Part Numbers Installation Manual Notes
A-40 (P/N 590-0052) P/N 560-0253-xx Open Circuit
A-41 (P/N 590-0051) P/N 560-0215-xx DC Grounded
NOTE
Certain types of transponder antennas that utilize very thin radiator elements are only
intended for use at 1030 and 1090 MHz. These types of antennas should be evaluated on
a model-by-model basis to determine their suitability as UAT data link antennas.
CAUTION
Operating the GDL 90 without RF terminations on the Top or Bottom UAT Antenna
ports can result in equipment damage. Always operate the GDL 90 with the Top and
Bottom UAT Antenna ports terminated with a VSWR ratio of 3.0:1 or less.

General Information
1-8 560-1049-02 Rev. B GDL 90 Installation Manual
1.4 Regulatory Compliance
1.4.1 TSO and Advisory Circular References
•TSO-C154 Universal Access Transceiver (UAT) Automatic Dependent Surveillance –
Broadcast (ADS-B) Equipment Operating on the Frequency of 978 MHz.
•TSO-C145A Airborne Navigation Sensors using GPS Augmented by WAAS
NOTE
Unauthorized changes or modifications to the GDL 90 may void the compliance to
required regulations and authorization for continued equipment usage.
1.4.2 TSO Authorization
Table 1-2. TSO Authorization
Function TSO
Minimum Performance
Standard
Software
RTCA/DO-178B
UAT Transceiver TSO-C154, Class A1H, B1 RTCA/DO-282 Level B, C
GPS/WAAS TSO-C145A, Class 1 RTCA/DO-229C, Class 1 Level B
1.4.3 TSO Deviations
Table 1-3 lists the GDL 90 TSO deviations.
Table 1-3. TSO Deviations
TSO Deviation
TSO-C145a 1. Garmin was granted a deviation from TSO-C145a with regard to the Initial Acquisition Time
requirements as stated in RTCA/DO-229c paragraph 2.1.1.7.
2. Garmin was granted a deviation from TSO-C145a with regard to the GPS Satellite Acquisition
Time requirements as stated in RTCA/DO-229c paragraph 2.1.1.8.1
3. Garmin was granted a deviation from TSO-C145a with regard to the WAAS Satellite Acquisition
Time requirements as stated in RTCA/DO-229c paragraph 2.1.1.8.2
4. Garmin was granted a deviation from TSO-C145a with regard to Satellite Reacquisition Time as
stated in RTCA/DO-229c paragraph 2.1.1.9
5. Garmin was granted a deviation from TSO-C145a with regard to Accuracy as stated in
RTCA/DO-229c paragraph 2.1.2.1.
TSO-C154 1. Garmin was granted a deviation from TSO-C154 to implement the requirements in the draft
RTCA/DO-282A prior to plenary approval.
The TSO-145a deviations degrade the GDL 90 availability as compared to fully-compliant equipment.
The installation of the GDL 90 must also comply with the operational limitations shown in Chapter 3 of
this document.
1.4.4 FCC Grant of Equipment Authorization
The GDL 90 has been issued an FCC Grant of Equipment Authorization. The FCC ID is marked on the
equipment nameplate.
1.4.5 GDL 90 STC Authorization
Refer to the GDL 90 Product CD 140-0063-xx for data regarding GDL 90 STC authorization.

General Information
GDL 90 Installation Manual 560-1049-02 Rev. B 1-9
1.5 Unpacking the Equipment
Carefully unpack the equipment. Visually inspect the package contents for any evidence of shipping
damage. Retain all shipping containers and packaging material in case reshipment is necessary.
1.6 Package Contents
As shipped from the Garmin AT factory, the GDL 90 package includes most necessary items for
installation other than supplies normally available at the installation shop, such as wire and cable ties,
circuit breakers, and required input and output equipment. The items included in the package are listed in
Table 1-4 and Table 1-5. In addition, Table 1-6 lists optional parts that may be needed for non-standard
installations. The GPS antenna may be provided separately as required for the specific installation.
Table 1-4. Package Contents
Part # Qty Description
424-6081-1xx 1 GDL 90 Installation Kit (see Table 1-5 for detail)
430-6081-1xx-xxx 1 GDL 90 UAT Data Link Sensor
140-0063-xx 1 GDL 90 Product CD
590-0051 OR 2 UAT Blade Antenna, passive, TNC
590-0052

General Information
1-10 560-1049-02 Rev. B GDL 90 Installation Manual
Table 1-5. Installation Kit Contents (PN 424-6081-100)
Part # Qty Description
162-0043 3 Connector, coax, RA, PNL MNT
265-0007 3 Retainer Ring, ext,7/16 shaft
240-0008 3 Washer, 0.446 ID 0.56 OD
162-1574 1 Receptacle DSUB 9-pin
162-1575 1 Receptacle DSUB 15-pin
162-1577 1 Receptacle DSUB 37-pin
162-2080 3 Connector, coax, RA, plug clamp, TNC
202-0002 8 Cable tie
224-0404 4 Screw, 4-40 x 1/4 SS flat head Phillips 82 deg.
245-0027 25 Crimp contact, DSUB, 20 to 24 AWG wire
310-0461-00 1 Cover Mounting Tray GDL 90
310-0462-00 1 Mounting Tray GDL 90
430-6200-000 1 Aircraft Personality Module (APM)
660-0014 50 Cable, coax RG400 dbl shield 50-ohm (feet)
Table 1-6. Optional Parts
Part # Description
310-0467-xx Capstone Phase 1 Adapter Plate
500-0290-xx Capstone Phase 1 Adapter Cable
560-1057-xx GDL 90 Capstone Upgrade Instructions
1.7 Definitions & Acronyms
ADC Air Data Computer
ADS-B Automatic Dependant Surveillance - Broadcast
AHRS Attitude Heading Reference System
ALT Altitude
APM Aircraft Personality Module
EN Engineering Notice
FIS-B Flight Information Services - Broadcast
GPS Global Positioning System
MFD Multi-Function Display
SBAS Satellite Based Augmentation Systems
STC Supplementary Type Certificate
TIS-B Traffic Information Service - Broadcast
TSO Technical Standard Order
UAT Universal Access Transceiver
WAAS Wide Area Augmentation System

Installation Procedures
GDL 90 Installation Manual 560-1049-02 Rev. B 2-1
2 Installation
This section describes the installation of the GDL 90 including mounting, wiring, and connections. Post-
Installation configuration and checkout procedures are included in Section 3.
2.1 Pre-Installation Information
Always follow acceptable avionics installation practices per FAA Advisory Circulars (AC) 43.13-1B,
43.13-2A, or later FAA approved revisions of these documents.
Follow the installation procedure in this section as it is presented for a successful installation. Read the
entire section before beginning the procedure. Prior to installation, consider the structural integrity of the
GDL 90 installation as defined in AC 43.13-2A, Chapter 1. Perform the post installation checkout before
closing the work area in case problems occur.
Complete an electrical load analysis in accordance with AC 43.13-1B, Chapter 11, on the aircraft prior to
starting modification to ensure aircraft has the ability to carry the GDL 90 load. Refer to Section 2.10 for
the power consumption of each GDL 90 mode of operation. Document the results of the electrical load
analysis on FAA Form 337.
The WAAS/GPS installation instructions have been prepared to meet the guidance material defined in
AC20-138A Airworthiness Approval of Global Navigation Satellite System (GNSS) Equipment.
CAUTION
Operating the GDL 90 without RF terminations on the Top or Bottom UAT Antenna
ports can result in equipment damage. Always operate the GDL 90 with the Top and
Bottom UAT Antenna ports terminated with a VSWR ratio of 3.0:1 or less.
2.2 Installation Overview
A successful installation should start with careful planning, including determination of mounting location
for the GDL 90, cable routing, and other required modifications. Once the mounting location has been
determined, prepare the mounting tray for installation. It may be easier to complete the wiring harness
and attach the connectors to the tray upon installation.
2.3 Materials Not Supplied
2.3.1 Materials Required But Not Supplied
The GDL 90 is intended for use with standard aviation accessories. The following items are required for
the installation, but not supplied:
•Wire (MIL-W-22759/16 or equivalent)
•Shielded wire (MIL-C-27500 or equivalent)
•Circuit Breakers
•Ring Terminals (for grounding)

Installation Procedures
2-2 560-1049-02 Rev. B GDL 90 Installation Manual
2.4 Special Tools Required
Some of the connectors use crimp contacts. The tables below identify crimp tools required to ensure
consistent, reliable crimp contact connections for the rear D-sub connectors. The tables define one source
for the crimp tool. Alternate equivalent tools may be used.
Table 2-1. Crimp Tool for P/N 245-0027
Description ITT/Cannon P/N Military Number
Insertion/Extraction tool CIET-20HD 980-200-426 M81969/39-01
Crimp tool 995-0001-584 M22520/2-01
Positioner 995-0001-604 M22520/2-08
Below is the contact for ITT/Cannon crimp tools:
ITT Cannon Phone [phone]
1851 E. Deere Ave FAX [phone]
Santa Ana, CA 92705-6500
Install the retainer ring for the coaxial connectors using external snap ring pliers, Diamond D32R or
equivalent. Note that the access holes inside the tray are enlarged and offset to provide access for the
pliers.
2.5 Equipment Mounting
2.5.1 Cabling and Wiring
Wiring should be installed in accordance with AC 43.13-1B Chapter 11. When wire separation cannot be
achieved, the following issues should be addressed:
•The cable harness should not be located near flight control cables and controls, high electrical
capacity lines or fuel lines
•The cable harness should be located in a protected area of the aircraft
•Do not route cable near high-energy sources
Refer to the interconnection diagrams in Appendix C for the appropriate wiring. Once the cable
assemblies have been made, attach the cable connectors to the rear of the mounting tray. Route the wiring
bundle as appropriate. Use 22 to 24 AWG wire for all connections except for power. Use 20 AWG for
power/ground. Avoid sharp bends.
2.5.2 Mounting Tray Installation
The GDL 90 does not require forced-air cooling; however, when mounting the GDL 90, avoid locating
the GDL 90 near sources that produce high levels of heat. The tray can be installed in a variety of
locations, such as the electronics bay, under a seat or behind the rear baggage area. Refer to Figure 2-1
and Figure 2-2 for suggested location. Leave sufficient clearance between the GDL 90 and any
obstruction. Install tray in accordance with AC 43.13-2A Chapter 2 Radio Installations. Tray should be
mounted to a surface known to have sufficient structural integrity to withstand additional inertia forces
imposed by a 6.4-pound unit. If it is necessary to build a shelf or bracket to mount the GDL 90 tray or it
is not certain that the chosen location is of sufficient structural integrity, refer to Appendix D.
Refer to Figure 2-3 for the GDL 90 tray dimensions. The tray can be mounted vertically using four 8-32
pan head screws (MS35206 or AN526 cadmium plated carbon steel.) It can also be mounted horizontally
using four 6-32 100° counter-sunk flathead screws (MS24693 or AN507R cadmium plated carbon steel.)
For installation in rotorcraft, the tray must be mounted vertically. See 561-0290-xxx GDL 90 Helicopter
Installation Supplement for additional rotorcraft installation requirements.