Garmin 01594 Users Manual

GTN 725/750

TSO Installation Manual

GTN 725 and GTN 750

190-01007-02 TBD 2010 Rev. A

©Copyright 2010

Garmin Ltd. or its subsidiaries

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

Revision Revision Date Description

A

Initial Release

GTN 725/750 TSO Installation Manual Page A
190-01007-02 Rev. A

DOCUMENT PAGINATION

Section Pagination

Table of Contents i - viii

Section 1 1-1 through 1-14
Section 2 2-1 through 2-12
Section 3 3-1 through 3-10
Section 4 4-1 through 4-28
Section 5 5-1 through 5-38
Section 6 6-1 through 6-2

Section 7 7-1 through 7-2
Appendix A A-1 through A-2
Appendix B B-1 through B-10
Appendix C C-1 through C-6
Appendix D D-1 through D-40

Page B GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

This manual is applicable for units with main software version 2.00 or later.

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.

Perchlorate Material – special handling may apply, See

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

.

WARNING

This product contains a Lithium battery that must be recycled or disposed of properly.
Battery replacement and removal must be performed by professional services.

GTN 725/750 TSO Installation Manual Page i
190-01007-02 Rev. A

GENERAL DESCRIPTION ............................................................................................................1-1

1.

1.1 Introduction ..............................................................................................................................1-1

1.2 Equipment Description.............................................................................................................1-1

1.3 Technical Specifications...........................................................................................................1-2

1.3.1 Physical Characteristics........................................................................................................1-2

1.3.2 General Specifications..........................................................................................................1-2

1.3.3 GPS Specifications...............................................................................................................1-3

1.3.4 COM Specifications (GTN 750 Only) .................................................................................1-4

1.3.5 VOR Specifications (GTN 750 Only)..................................................................................1-5

1.3.6 LOC Specifications (GTN 750 Only) ..................................................................................1-5

1.3.7 Glideslope Specifications (GTN 750 Only) .........................................................................1-6

1.3.8 GPS Antenna Requirements.................................................................................................1-7

1.4 License Requirements...............................................................................................................1-8

1.5 Regulatory Compliance ............................................................................................................1-9

1.5.1 TSO Authorization and Advisory Circular References........................................................1-9

1.5.2 TSO Deviations..................................................................................................................1-11

1.5.3 FCC Grant of Equipment Authorization ............................................................................1-11

1.6 Database Options and Updates ...............................................................................................1-12

1.6.1 Navigation Database ..........................................................................................................1-12

1.6.2 TAWS/Terrain Database ....................................................................................................1-12

1.7 Fault Detection and Exclusion (FDE) ....................................................................................1-12

1.8 Limited Warranty ...................................................................................................................1-13

2. INSTALLATION OVERVIEW ......................................................................................................2-1

2.1 Introduction ..............................................................................................................................2-1

2.2 Minimum System Configuration ..............................................................................................2-1

2.2.1 VFR Installation ...................................................................................................................2-1

2.2.2 IFR GPS Installation ............................................................................................................2-1

2.2.3 IFR VOR/LOC/GLIDESLOPE Installation.........................................................................2-2

2.3 External Sensors .......................................................................................................................2-2

2.3.1 Multiple Uncorrected Pressure Altitude Sources .................................................................2-2

2.3.2 Multiple Baro-Corrected Altitude Sources...........................................................................2-3

2.3.3 Multiple Heading Sources....................................................................................................2-3

2.3.4 Multiple Indicated Airspeed Sources ...................................................................................2-4

2.3.5 Multiple True Airspeed Sources ..........................................................................................2-4

2.3.6 Multiple VLOC Course Select Sources ...............................................................................2-4

2.3.7 GPS Course Select Sources..................................................................................................2-5

2.3.8 Total Air Temperature Sources ............................................................................................2-5

2.3.9 Static Air Temperature Sources ...........................................................................................2-5

2.3.10 Joystick Waypoint Data .......................................................................................................2-6

2.4 Antenna Considerations............................................................................................................2-7

2.4.1 GPS Antenna Location.........................................................................................................2-7

2.4.2 COM Antenna Location.......................................................................................................2-8

2.4.3 VOR/LOC Antenna Location.............................................................................................2-10

2.4.4 Glideslope Antenna Location.............................................................................................2-10

2.4.5 Electrical Bonding..............................................................................................................2-10

2.4.6 Interference of GPS............................................................................................................2-10

2.5 Mounting Considerations .......................................................................................................2-11

2.6 Cabling and Wiring Considerations .......................................................................................2-11

Page ii GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

Air Circulation and Cooling ...................................................................................................2-11

2.7

2.8 Compass Safe Distance ..........................................................................................................2-11

3. INSTALLATION PROCEDURES..................................................................................................3-1

3.1 Unit and Accessories ................................................................................................................3-1

3.2 Optional Accessories ................................................................................................................3-2

3.2.1 GPS Antenna Options ..........................................................................................................3-2

3.3 Database Options......................................................................................................................3-3

3.4 Miscellaneous Options .............................................................................................................3-3

3.5 Optional Reference Material ....................................................................................................3-3

3.6 Installation Materials Required but Not Provided....................................................................3-4

3.6.1 Optional Accessories Not Supplied......................................................................................3-4

3.6.2 Materials Required But Not Supplied (New Installations Only)..........................................3-4

3.7 Special Tools Required.............................................................................................................3-4

3.8 Cable Installation......................................................................................................................3-5

3.9 Equipment Mounting................................................................................................................3-7

3.9.1 Rack Installation...................................................................................................................3-7

3.9.2 GTN Unit Insertion and Removal ........................................................................................3-7

3.9.3 Unit Replacement.................................................................................................................3-7

3.10 Antenna Installation and Connections......................................................................................3-8

3.10.1 GPS Antenna........................................................................................................................3-8

3.10.2 COM Antenna ......................................................................................................................3-9

3.10.3 NAV Antenna.......................................................................................................................3-9

4. SYSTEM INTERCONNECTS ........................................................................................................4-1

4.1 Pin Function List ......................................................................................................................4-1

4.1.1 P1001 Main Connector – Main Board .................................................................................4-1

4.1.2 P1002 Connector..................................................................................................................4-3

4.1.3 P1003 COM Connector........................................................................................................4-4

4.1.4 P1004 NAV Connector ........................................................................................................4-5

4.2 I/O Board ..................................................................................................................................4-7

4.2.1 P1005 Connector..................................................................................................................4-7

4.3 Power, Lighting, And Antennas ...............................................................................................4-9

4.3.1 Power....................................................................................................................................4-9

4.3.2 Lighting Bus.........................................................................................................................4-9

4.3.3 Antennas...............................................................................................................................4-9

4.3.4 Serial Data..........................................................................................................................4-10

4.3.5 Ethernet (HSDB)................................................................................................................4-15

4.3.6 Main Audio Output ............................................................................................................4-15

4.3.7 Main Indicator....................................................................................................................4-16

4.3.8 OBS....................................................................................................................................4-17

4.3.9 Discrete Inputs ...................................................................................................................4-17

4.3.10 Discrete Outputs.................................................................................................................4-19

4.3.11 Heading Synchro................................................................................................................4-21

4.3.12 Composite Video (function not currently implemented) ...................................................4-22

4.3.13 COM Audio (GTN 750 only).............................................................................................4-23

4.3.14 COM Discrete Inputs .........................................................................................................4-24

4.3.15 VOR/ILS Indicator (GTN 750 only)..................................................................................4-25

4.3.16 RMI/OBI (GTN 750 only) .................................................................................................4-27

4.3.17 DME Tuning (GTN 750 only) ...........................................................................................4-28

GTN 725/750 TSO Installation Manual Page iii
190-01007-02 Rev. A

5.

POST INSTALLATION CONFIGURATION AND CHECKOUT PROCEDURES .....................5-1

5.1 System Configuration Overview ..............................................................................................5-1

5.2 Mounting, Wiring, and Power Checks .....................................................................................5-1

5.3 Connector Engagement Check .................................................................................................5-2

5.4 Configuration Mode Operations...............................................................................................5-2

5.4.1 Main ARINC 429 Config Page ............................................................................................5-3

5.4.2 Main RS-232 Config Page ...................................................................................................5-6

5.4.3 HSDB (Ethernet) Configuration Page..................................................................................5-8

5.4.4 Interface Equipment Page ....................................................................................................5-8

5.4.5 Main CDI Indicator (Analog) Configuration Page...............................................................5-9

5.4.6 Lighting Configuration Page..............................................................................................5-10

5.4.7 Audio Configuration Page..................................................................................................5-12

5.4.8 Traffic Configuration Page.................................................................................................5-13

5.4.9 Main System Configuration Page ......................................................................................5-13

5.4.10 COM Configuration Page (GTN 750 Only)......................................................................5-14

5.4.11 VOR/LOC/GS Configuration Page....................................................................................5-15

5.5 Ground Checks (Configuration Mode)...................................................................................5-17

5.5.1 Main Indicator Check (Analog Only) ................................................................................5-17

5.5.2 VOR/ILS Indicator (Analog) .............................................................................................5-17

5.5.3 Discrete Inputs Checkout ...................................................................................................5-17

5.5.4 Discrete Outputs Checkout.................................................................................................5-18

5.5.5 HSDB Provisional Wiring Checkout .................................................................................5-18

5.5.6 TAWS Audio Check (For Units with TAWS Only) ..........................................................5-19

5.5.7 GAD 42 Interface Check....................................................................................................5-20

5.5.8 Lighting Bus Interface Check ............................................................................................5-20

5.6 Ground Checks (Normal Mode) .............................................................................................5-21

5.6.1 Display of Self-Test Data...................................................................................................5-21

5.6.2 Signal Acquisition Check...................................................................................................5-22

5.6.3 VHF COM Interference Check ..........................................................................................5-22

5.6.4 VHF NAV Checkout (GTN 750 Only) ..............................................................................5-24

5.6.5 VHF COM Checkout (GTN 750 Only)..............................................................................5-24

5.6.6 TAWS System Check (For Units with TAWS Only) ........................................................5-24

5.6.7 Altitude Encoder or Air Data Computer Check .................................................................5-25

5.6.8 AHRS/IRU Interface Check...............................................................................................5-25

5.6.9 Interface Checkout .............................................................................................................5-26

5.6.10 Magnetic Compass Check..................................................................................................5-31

5.7 Flight Checks..........................................................................................................................5-32

5.7.1 GPS Flight Check............................................................................................................... 5-32

5.7.2 VHF COM Flight Check (GTN 750) .................................................................................5-32

5.7.3 VOR Flight Check (GTN 750)...........................................................................................5-32

5.7.4 ILS Flight Check (GTN 750) .............................................................................................5-33

5.7.5 Autopilot Flight Check.......................................................................................................5-33

5.7.6 TAWS Audio Flight Check (TAWS-equipped Units Only) ..............................................5-33

5.8 Database Check ......................................................................................................................5-33

5.9 Data Card Replacement .......................................................................................................... 5-34

5.10 Software Loading ...................................................................................................................5-34

5.11 System Setup ..........................................................................................................................5-34

5.12 Documentation Checks...........................................................................................................5-34

Page iv GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

Airplane Flight Manual Supplement ..................................................................................5-34

5.12.1

5.12.2 Instructions for Continued Airworthiness (ICAW)............................................................5-34

5.13 Configuration and Checkout Log ...........................................................................................5-35

6. LIMITATIONS................................................................................................................................6-1

6.1 Operations.................................................................................................................................6-1

6.2 Installation ................................................................................................................................6-1

6.2.1 GPS Antenna........................................................................................................................6-1

6.3 Aircraft Radio Station License .................................................................................................6-1

7. PERIODIC MAINTENANCE .........................................................................................................7-1

7.1 Equipment Calibration..............................................................................................................7-1

7.2 VOR Checks.............................................................................................................................7-1

7.3 Cleaning....................................................................................................................................7-1

7.4 Battery Replacement.................................................................................................................7-1

Appendix A ENVIRONMENTAL QUALIFICATION FORM..........................................................A-1

Appendix B GTN DATA FORMAT ..................................................................................................B-1

B.1 RS-232 Aviation Data Format................................................................................................. B-1

B.1.1 Electrical Interface .............................................................................................................. B-1

B.1.2 General Output Format ....................................................................................................... B-1

B.1.3 Output Sentence Type 1 ...................................................................................................... B-1

B.1.4 Output Sentence Type 2 ...................................................................................................... B-3

B.2 GTN RS-232 Fuel/Air Data Input Format............................................................................... B-5

B.2.1 Electrical Interface .............................................................................................................. B-5

B.2.2 Shadin Altitude Sentence .................................................................................................... B-5

B.2.3 Icarus Altitude Sentence...................................................................................................... B-5

B.2.4 Shadin Fuel Flow Sentence................................................................................................. B-6

B.2.5 ARNAV/EI Fuel Flow Sentence ......................................................................................... B-6

B.2.6 Shadin Fuel/Air Data Computer Sentence ..........................................................................B-7

Appendix C MECHANICAL DRAWINGS .......................................................................................C-1

C.1 Drawing List............................................................................................................................C-1

Appendix D INTERCONNECT DIAGRAMS....................................................................................D-1

D.1 Drawing List............................................................................................................................D-1

GTN 725/750 TSO Installation Manual Page v
190-01007-02 Rev. A

LIST OF FIGURES

Figure 2-1. GPS Antenna Installation Considerations ..............................................................................2-9

Figure 3-1. Coaxial Cable Installation ......................................................................................................3-5

Figure 5-1. Configuration Mode Home Page............................................................................................5-2

Figure 5-2. Main ARINC 429 Configuration Page...................................................................................5-3

Figure 5-3. Main GTN Setup Page ...........................................................................................................5-3

Figure 5-4. Main RS-232 Configuration Page..........................................................................................5-6

Figure 5-5. HSDB Ethernet Port Configuration Page...............................................................................5-8

Figure 5-6. Main CDI Configuration Page ...............................................................................................5-9

Figure 5-7. Main Lighting Configuration Page ......................................................................................5-10

Figure 5-8. Photocell Configuration Page...............................................................................................5-11

Figure 5-9. Lighting Bus Configuration Page..........................................................................................5-12

Figure 5-10. Audio Configuration Page..................................................................................................5-12

Figure 5-11. COM Configuration Page...................................................................................................5-14

Figure 5-12. Traffic Configuration Page.................................................................................................5-13

Figure 5-13. Miscellaneous Configuration Page.....................................................................................5-13

Figure 5-14. Measurement of GPS Antenna Vertical Offset ..................................................................5-14

Figure 5-15. VOR/LOC/GS Configuration Page....................................................................................5-15

Figure 5-16. GTN Diagnostics Page.......................................................................................................5-17

Figure 5-17. HSDB Diagnostics Page.....................................................................................................5-18

Figure 5-18. GTN Audio Configuration Page ........................................................................................5-19

Figure 5-19. GAD 42 Configuration Page..............................................................................................5-20

Figure 5-20. Lighting Bus Configuration Page.......................................................................................5-20

Figure 5-21. Map Menu Page .................................................................................................................5-25

Figure C-1. GTN Mounting Rack Dimensions........................................................................................ C-3

Figure C-2. GTN Mounting Rack Installation .........................................................................................C-4

Figure C-3. GTN Mounting Rack Assembly ...........................................................................................C-5

Figure C-4. GTN Recommended Panel Cutout Dimensions ...................................................................C-6

Figure D-1. GTN System Interface Diagram........................................................................................... D-3

Figure D-2. GTN 750 Typical Installation...............................................................................................D-4

Figure D-3. GTN 725 Typical Installation...............................................................................................D-6

Figure D-4. GTN Power Lighting Configuration Interconnect ...............................................................D-8

Figure D-5. GTN – Antenna Interconnect ............................................................................................. D-10

Figure D-6. GTN - Main Indicator Interconnect....................................................................................D-13

Figure D-7. GTN - Autopilot Interconnect ............................................................................................D-14

Figure D-8. GTN - Traffic Interconnect ................................................................................................D-15

Figure D-9. GTN - Transponder Interconnect ....................................................................................... D-16

Figure D-10. Dual GTN to Single GDU Interconnect ........................................................................... D-17

Figure D-11. GTN - GDU/AHRS Interconnect ..................................................................................... D-18

Figure D-12. GTN - ARINC 429 EFIS Interconnect.............................................................................D-19

Figure D-13. GTN - GDL 69/69A Interconnect .................................................................................... D-21

Figure D-14. Audio Panel Interconnect .................................................................................................D-22

Figure D-15. Air Data/IRU/AHRS RS-232 Interconnect ......................................................................D-24

Figure D-16. Air Data/IRU/AHRS ARINC 429 Interconnect ...............................................................D-26

Figure D-17. GAD 42 Interconnect .......................................................................................................D-27

Figure D-18. VOR/ILS Indicator Interconnect ......................................................................................D-28

Figure D-19. RMI OBI Interconnect...................................................................................................... D-29

Figure D-20. GTN – WX-500 Interconnect...........................................................................................D-30

Figure D-21. GTN 750 - DME Interconnect.......................................................................................... D-31

Figure D-22. GTN 750 – Remote DME Interconnect............................................................................D-32

Figure D-23. Parallel 2 of 5 DME Tuning............................................................................................. D-33

Figure D-24. Parallel Slip Code DME Tuning Interconnect..................................................................D-34

Page vi GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

Figure D-25. Heading Synchro Interconnect .........................................................................................D-35

Figure D-26. GPS Annunciator Interconnect.........................................................................................D-36

Figure D-27. NAV Source Select Annunciator Interconnect.................................................................D-37

Figure D-28. TAWS Interconnect..........................................................................................................D-38

Figure D-29. Switches Interconnect....................................................................................................... D-39

Table 1-1. GTN Units ...............................................................................................................................1-1

Table 1-2. GTN Current Specifications ....................................................................................................1-6

Table 1-3. Approved GPS Antennas.........................................................................................................1-7

Table 1-4. TSO Authorization ..................................................................................................................1-9

Table 1-5. Main Software Part Number and Version .............................................................................1-10

Table 1-6. GPS/WAAS Software Part Number and Version..................................................................1-10

Table 3-1. Catalog Part Numbers..............................................................................................................3-1

Table 3-2. Standard Kit Accessories.........................................................................................................3-1

Table 3-3. Recommended Crimp Tools (or Equivalent)...........................................................................3-4

Table 3-4. Socket Contact Part Numbers..................................................................................................3-6

Table 5-1. GTN Post-Installation Checkout Log ....................................................................................5-35

LIST OF TABLES

Table B-1. Type 1 Output Sentence Format ............................................................................................ B-2

Table B-2. Type 2 Output Sentence Format ............................................................................................ B-4

GTN 725/750 TSO Installation Manual Page vii
190-01007-02 Rev. A

GTN 725/750 HARDWARE MOD LEVEL HISTORY

The following table identifies hardware modification (Mod) Levels for the GTN 725 and GTN 750. 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.

SERVICE

MOD LEVEL

BULLETIN

NUMBER

SERVICE BULLETIN

DATE

PURPOSE OF MODIFICATION

Page viii GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1. GENERAL DESCRIPTION

1.1 Introduction

This manual describes the physical, mechanical, and electrical characteristics, as well as instructions and
other conditions and limitations for installation and approval of the GTN units. Refer to Section 6,
Limitations, for additional information and other considerations.

NOTE

Except where specifically noted, references made to GTN will equally apply to the
GTN 725 and GTN 750.

Table 1-1. GTN Units

MODEL PART NUMBER COLOR NOTES

GTN 725

GTN 750

011-02281-00 BLACK

011-02282-00 BLACK 10 WATT UNIT

011-02282-10 GRAY 10 WATT UNIT

1.2 Equipment Description

The GTN 725 is a GPS/WAAS unit that meets the requirements of TSO-C146a (specified in Table 1-4)
and may be approved for IFR en route, terminal, non-precision, and precision approach operations.

The GTN 750 includes all the features of the GTN 725 and includes an airborne VHF communications
transceiver and airborne VOR/LOC and glideslope receivers. The GTN 750 meets the requirements of the
TSOs specified in Table 1-4.

CAUTION

The GTN use lenses coated with a special anti-reflective coating that is very sensitive to
waxes and abrasive cleaners. CLEANERS CONTAINING AMMONIA WILL HARM
THE ANTI-REFLECTIVE COATING. It is very important to clean the lens using a
clean, lint-free cloth and an eyeglass lens cleaner that is specified as safe for anti­reflective coatings.

CAUTION

The use of ground-based cellular telephones while aircraft are airborne is prohibited by
FCC rules. Due to potential interference with onboard systems, the use of ground-based
cell phones while the aircraft is on the ground is subject to FAA regulation 14
CFR §91.21.

FCC regulation 47 CFR §22.925 prohibits airborne operation of ground-based cellular
telephones installed in or carried aboard aircraft. Ground-based cellular telephones must
not be operated while aircraft are off the ground. When any aircraft leaves the ground, all
ground-based cellular telephones on board that aircraft must be turned off. Ground-based
cell phones that are on, even in a monitoring state, can disrupt GPS performance.

CAUTION

All screen shots used in this document are current at the time of publication. Screen shots
are intended to provide visual reference only. All information depicted in screen shots,
including software file names, versions, and part numbers, is subject to change and may
not be up to date.

GTN 725/750 TSO Installation Manual Page 1-1
190-01007-02 Rev. A

1.3 Technical Specifications

1.3.1 Physical Characteristics

Bezel Height

Bezel Width

Rack Height (Dimple-to-Dimple)

Rack Width

Depth Behind Panel with Connectors (Measured from
face of aircraft panel to rear of connector backshells)

GTN 725 Weight (Unit only)

GTN 725 Weight (With rack and back plate)

GTN 750 Weight (Unit only)

GTN 750 Weight (With rack and back plate)

1.3.2 General Specifications

Operating Temperature Range

Humidity
Altitude Range
Input Power Requirements
Input Voltage Range - All Units (Main Connector)
Input Voltage Range (COM Connector on GTN 750)
Input Voltage Range (NAV Connector on GTN 750)
GTN Current Draw
Superflag Power Requirements

Environmental Testing

6.00 in. (152 mm)

6.25 in. (159 mm)

6.025 in. (153 mm)

6.300 in (160 mm)

11.25 in. (286 mm)

TBD

TBD

7.50 lbs (3.40 kg)

9.16 lbs (4.15 kg)

-20°C to +55°C. For more details see
Environmental Qualification Form on the
Dealers Only page on www.garmin.com. See
Appendix A for part numbers.
95% non-condensing

-1,500 ft to 50,000 ft

9 to 33 VDC
9 to 33 VDC
9 to 33 VDC
Refer to Table 1-2
400 mA maximum per superflag output
See Environmental Qualification Form on the
Dealers Only page on www.garmin.com. See
Appendix A for part numbers.

The display on the GTN is a sunlight readable LCD display.

Display Size
Active Area
Resolution

Viewing Angle

6.9 inch diagonal

4.46 inches (W) x 5.27 inches (H)
600 x 708 pixels
Left/Right: 45°
Up: 10°
Down: 30°

Page 1-2 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.3.3 GPS Specifications

Number Of Channels
Frequency

Sensitivity (Acquisition, No Interference)

Sensitivity (Drop Lock)
Dynamic Range
Lat/Lon Position Accuracy
Velocity
TTFF (Time To First Fix)
Reacquisition
Position Update Interval
1 PPS (Pulse Per Second)
Datum

SATCOM Compatibility

Antenna Power Supply

15 (12 GPS and 3 GPS/WAAS/SBAS)

1575.42 MHz L1, C/A code

-134.5 dBm GPS

-135.5 dBm WAAS

-144 dBm
> 20 dB
<1.25 meter RMS horizontal, <2 meter vertical, with WAAS
1000 knots maximum (above 60,000 ft)
1:45 min. typical with current almanac, position, and time
10 seconds typical

0.2 sec (5 Hz)
±275 Nsec of UTC second
WGS-84
SATCOM compatibility is dependent upon antenna selection.

See Section TBD for additional information.
35 mA typical, 40 mA max at 4.7 VDC

GTN 725/750 TSO Installation Manual Page 1-3
190-01007-02 Rev. A

1.3.4 COM Specifications (GTN 750 Only)

1.3.4.1 COM Transmitter Specifications

Classes

Microphone Input

Modulation Capability
Modulation
Frequency Range
Frequency Tolerance

Output Power

Duty Cycle

Carrier Noise Level
Stuck Mic Time-Out

Demodulated Audio Distortion

Sidetone

3,4,5,6
Two inputs, standard carbon or dynamic mic with integrated

preamp providing minimum 70 mVRMS into 1000 load
85% with 100 to 1000 mVRMS microphone input at 1000 Hz
AM Double sided, Emission Designator 6K00A3E

118.000 to 136.975 MHz, 25 kHz and 8.33 kHz channel spacing
+/-2ppm from -40°C to +70°C
10 Watt Mode: 10 watts minimum

16 Watt Mode: 16 watts minimum
10W: 100%

16W: Recommended 25% (15 seconds on/45 seconds off,

5 seconds on/15 seconds off, etc.)
At least 35 dB (SNR).
35 seconds time-out, reverts to receive
Less than 5% distortion when the transmitter is at 85%

modulation at 350 to 2500 Hz

1.4 Vrms into a 500 load

1.3.4.2 COM Receiver Specifications

Classes
Frequency Range
Headset Audio Output
Speaker Audio Output
Audio Response
Audio Distortion

AGC Characteristics

Sensitivity

Squelch

Selectivity

D and E

118.000 to 136.975 MHz, 25 kHz and 8.33 kHz channel spacing
110 mW minimum into a 500 load
12 watts minimum into a 4 load
Less than 6 dB of variation between 350 and 2500 Hz.
Less than 5% at rated output power
Less than 3 dB of variation in the audio output from -93 to -13

dBm (power absorbed by a 50Ω load)
SINAD on all channels is greater than 6 dB when the RF level is

2 uV (hard) or -107 dBm (power absorbed by a 50Ω load)
modulated 30% at 1000 Hz at rated audio output power

Automatic squelch with manual override
6 dB BW is greater than +

60 dB BW is less than ±22 kHz for 25 kHz channeling.
6 dB BW is greater than ±3.5 kHz for 8.33 kHz channeling.
60 dB BW is less than ±7.37 kHz for 8.33 kHz channeling.

7 kHz for 25 kHz channeling.

Page 1-4 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.3.5 VOR Specifications (GTN 750 Only)

Receiver Audio Sensitivity
Course Deviation Sensitivity

Flag

AGC Characteristics

Spurious Response

VOR OBS Bearing Accuracy

Audio Output

Audio Response

Audio Distortion

At -103.5 dBm (S+N)/N is not less than 6 dB.

-103.5 dBm or less for 60% of standard deflection.
The VOR Course Deviation Flag must be flagged:

in the absence of an RF signal.
in the absence of the 9960 Hz modulation.
in the absence of either one of the two 30 Hz modulations.
When the level of a standard VOR deviation test signal produces

less than a 50% of standard deflection.
From -99 dBm to -13 dBm input of a Standard VOR Audio Test

Signal, audio output level does not vary more than 3 dB.
Greater than 80 dB.
The bearing information as presented to the pilot does not have an

error in excess of 2.7° as specified by RTCA DO-196 and
EuroCAE ED-22B.

A minimum 100 mW into a 500Ω load.
Less than 6 dB of variation between 350 and 2500 Hz. Except the

1020 Hz Ident Tone is at least 20 dB down in voice mode.
The distortion in the receiver audio output does not exceed 10% at

all levels up to 100 mW.

1.3.6 LOC Specifications (GTN 750 Only)

Receiver Audio Sensitivity
Course Deviation Sensitivity

Flag

AGC Characteristics

Spurious Response

VOR OBS Bearing Accuracy

Audio Output

Audio Response

Audio Distortion

At -103.5 dBm (S+N)/N is not less than 6 dB.

-103.5 dBm or less for 60% of standard deflection.
The VLOC Course Deviation Flag must be flagged:

in the absence of an RF signal.
in the absence of the 9960 Hz modulation.
in the absence of either one of the two 30 Hz modulations.
When the level of a standard VOR deviation test signal produces
less than a 50% of standard deflection.

From -99 dBm to -13 dBm input of a Standard VOR Audio Test
Signal, audio output level does not vary more than 3 dB.

Greater than 80 dB.
The bearing information as presented to the pilot does not have an

error in excess of 2.7° as specified by RTCA DO-196 and
EuroCAE ED-22B.

A minimum 100 mW into a 500Ω load.
Less than 6 dB of variation between 350 and 2500 Hz. Except the

1020 Hz Ident Tone is at least 20 dB down in voice mode.
The distortion in the receiver audio output does not exceed 10% at

all levels up to 100 mW.

GTN 725/750 TSO Installation Manual Page 1-5
190-01007-02 Rev. A

1.3.7 Glideslope Specifications (GTN 750 Only)

Sensitivity

Centering Accuracy

Selectivity

Standard Deflection

Flag

-87 dBm or less for 60% of standard deflection.

0 ±.0091 ddm or 0 ±7.8 mV.

The course deviation is 0 ddm ± .0091 ddm when using the
Glideslope Centering Test Signal as the RF frequency is varied
±17 kHz from the assigned channel.

At frequencies displaced by ±132 kHz or greater, the input signal is
at least 60 dB down.

a) With a standard deflection ‘FLY DOWN’ condition (90 Hz
dominant), the output is -78 mV ±7.8 mV.

b) With a standard deflection ‘FLY UP’ condition (150 Hz
dominant), the output is +78 mV ±7.8 mV.

The unit Flags:
When the level of a standard deviation test signal produces 50% or

less of standard deflection of the deviation indicator.
In the absence of 150 Hz modulation.
In the absence of 90 Hz modulation.
In the absence of both 90 Hz and 150 Hz modulation.
In the absence of RF.

Table 1-2. GTN Current Specifications

LRU

GTN 725

Main Connector 1.123 A

GTN 750

Main Connector 1.123 A
COM Connector 470 mA (RX)

NAV Connector 308 mA

14 Volt Current Draw 28 Volt Current Draw

Typical Maximum Typical Maximum

220 mA (RX)

5.16 A (TX:10W)

6.93 A (TX:16W)

2.04 A (TX:10W)

2.73 A (TX:16W)

Page 1-6 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.3.8 GPS Antenna Requirements

Antenna performance is critical to the GPS/WAAS operation. The antennas listed in Table 1-3 are
approved for installation with the GTNs.

Table 1-3. Approved GPS Antennas

Model/Description Conn Type Mfr Part Number

GA 35, GPS/WAAS

[1]

GA 36, GPS/WAAS TNC

GA 37, GPS/WAAS/XM TNC

A33W, WAAS Antenna

[3]

GPS/VHF Antenna

GPS/VHF Antenna

GPS/XM/VHF Antenna

GPS/XM/VHF Antenna

GPS Antenna TNC Comant [3] CI-428-200 N/A

GPS/XM Antenna TNC/TNC Comant [3] CI-428-410 N/A

TNC

TNC

TNC/BNC

[2]

TNC/BNC

[2]

TNC/TNC/BNC

[4]

TNC/TNC/BNC

[4]

Garmin 013-00235-( )

Aero Antenna AT575-93G( )-TNCF-000-RG-27-NM

Garmin 013-00244-( )

Aero Antenna AT575-126G( )-TNCF-000-RG-27-NM

Garmin 013-00245-( )

Aero Antenna AT2300-126G( )-TNCF-000-RG-27-NM

Garmin 013-00261-( )

Aero Antenna AT575-332G( )- TNCF-000-RG-27-NM

Comant [3] CI-2580-200 N/A

Comant [3] CI-2728-200 N/A

Comant [3] CI-2580-410 N/A

Comant [3] CI-2728-410 N/A

Garmin

Order

Number

013-00235-( )

013-00244-( )

013-00245-( )

013-00261-( )

[1] Same mounting hole pattern as GA 56, but GA 35 antenna has a physically larger footprint.
[2] The GPS/WAAS connector is a TNC type. The VHF connector is a BNC type.
[3] Installation of this antenna is not covered by the Garmin GA Antenna AML STC SA01695SE.
[4] The GPS/WAAS connector is a TNC type. The XM connector is a TNC type. The VHF connector is

a BNC type.

GTN 725/750 TSO Installation Manual Page 1-7
190-01007-02 Rev. A

1.4 License Requirements

The Telecommunications Act of 1996, effective February 8, 1996, provides the FCC discretion to
eliminate radio station license requirements for aircraft and ships. The GTN 725 and GTN 750
installations must comply with current transmitter licensing requirements. In the US, to find out the
specific details on whether a particular installation is exempt from licensing, please visit the FCC web site
http://wireless.fcc.gov/aviation. If an aircraft license is required, make application for a license on FCC
form 404, Application for Aircraft Radio Station License. The FCC also has a fax-on-demand service to
provide forms by fax. Outside the US, contact the responsible telecommunication authority. The GTN
725 and GTN 750 owner accepts all responsibility for obtaining the proper licensing before using the
transceiver. The maximum transmitting power, modulation identification, and frequency band
information may be required for licensing and are detailed in Section 1.4.4.

CAUTION

The VHF transmitter in this equipment is guaranteed to meet Federal Communications
Commission acceptance over the operating temperature range. Modifications not
expressly approved by Garmin could invalidate the license and make it unlawful to
operate the equipment.

Page 1-8 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.5 Regulatory Compliance

1.5.1 TSO Authorization and Advisory Circular References

The conditions and tests required for TSO approval of this article are minimum performance standards. It
is the responsibility of those installing this article either on or within a specific type or class of aircraft to
determine that the aircraft installation conditions are within the TSO standards. TSO articles must have
separate approval for installation in an aircraft. The article may be installed only in compliance with
14 CFR part 43 or the applicable airworthiness requirements.

Table 1-4. TSO Authorization

Minimum

Applicable SW

P/Ns

GTN 725

GTN 750

●

●

●

● ●

● ●

● ●

● ●

● ●

● ●

● ●

Function TSO

ILS Glideslope Receiving
Equipment
ILS Localizer Receiving
Equipment
VOR Receiving
Equipment
Airborne Weather and
Ground Mapping Pulsed
Radars
Airborne ATC
Transponder Equipment
Optional Display
Equipment for Weather
and Ground Mapping
Radar Indicators
Airborne Passive
Thunderstorm Detection
Equipment
Air Traffic Control Radar
Beacon System/Mode
Select ATCRABS/Mode S
Multipurpose Electronic
Displays

TCAS Airborne
Equipment

Environmental

Standard

TSO-C34e DO-160B DO-192 TBD

TSO-C36e DO-160B DO-195 TBD

TSO-C40c DO-160B DO-196 TBD

TSO-C63c DO-160A DO-173 TBD

TSO-C74d DO-160F DO-144A TBD

TSO-C105 DO-160A DO-174 TBD

TSO-C110a DO-160B DO-191 TBD

TSO-C112c DO-160F DO-181D TBD

TSO-C113 DO-160A AS 8034 TBD

TSO-C118 DO-160B DO-197 TBD

Operational

Performance

Standard

Class/Type

Equipment that
Prevents Blocked
Channels in

●

2-way Radio

TSO-C128a DO-160E DO-207 TBD

Communications due to
Unintentional
Transmissions

● ●

● ●

● ● TAS Airborne Equipment TSO-C147 DO-160D DO-197A TBD

● ● TAWS TSO-C151b DO-160E TSO-C151b TBD

Aircraft Audio Systems
and Equipment
Stand-Alone Airborne
Navigation Equipment
using the GPS
Augmented by the
Satellite Based
Augmentation System

TSO-C139 DO-160E DO-214 TBD

TSO-C146c DO-160E DO-229D TBD

GTN 725/750 TSO Installation Manual Page 1-9
190-01007-02 Rev. A

GTN 725

GTN 750

● ●

● ●

●

Function TSO

Aircraft Flight Information
Services – Broadcast
(FIS-B) Datalink Systems
and Equipment
Electronic Map Display
Equipment for Graphical
Depiction of Aircraft
Position
VHF Radio
Communications
Transceiver Equipment
Operating with Radio
Frequency Range

117.975 to 137.000 MHz

Table 1-5. Main Software Part Number and Version

Minimum

Environmental

Standard

TSO-C157 DO-160E DO-267A TBD

TSO-C165 DO-160E DO-257A TBD

TSO-C169a DO-160E DO-186B TBD

Operational

Performance

Standard

Class/Type

Applicable SW

Software Part Number Software Version

TBD TBD

P/Ns

Table 1-6. GPS/WAAS Software Part Number and Version

Software Part Number Software Version

006-B0339-10 V4.0

NOTE

For main or GPS software versions previous to those listed Table 1-5 or Table 1-6,
contact Garmin for assistance.

System Function DO-178B Level

Operating System B
GPS Navigation Information B
VOR Information C
LOC/Glideslope Information C
VHF Communication C
TAWS (Class B) Functionality C
Display of altitude, heading, course, speed, and track C
Display of other information - moving map, terrain, flight plan overlay and flight
mode, TAS/TIS traffic information, XM Weather data, data from passive lightning
detection equipment, checklist and timer
Terrain (Fixed Wing) D
Terrain Prox (Helicopter) D
HTAWS (Helicopter) C

D

NOTE

Unauthorized changes or modifications to any GTN unit product may void the
compliance to required regulations and authorization for continued equipment usage. All
GTN unit functions are design approved under the TSO.

Page 1-10 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.5.2 TSO Deviations

TSO Deviation

1. Garmin was granted a deviation from TSO-C110 not to mark the computer software level(s) on the unit.

TSO-C110

TSO-C113

TSO-C118

TSO-C139

TSO-C146c

TSO-C147

TSO-C151b

TSO-C165

2. Garmin was granted a deviation from the TSO-C110 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C113 not to mark the computer software level(s) on the unit.

2. Garmin was granted a deviation from TSO-C113 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C118 not to mark the computer software level(s) on the unit.

2. Garmin was granted a deviation from TSO-C118 to use RTCA/DO-197A instead of RTCA/DO-197 as the
Minimum Operational Performance Standards.

3. Garmin was granted a deviation from TSO-C118 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C139 not to furnish each person receiving a GTN 725/750 copies of
the data in Paragraph 5.l of the TSO.

2. Garmin was granted a deviation from TSO-C139 not to furnish each person receiving a GTN 725/750 copies of
the data in Paragraph 5.l, 5.m, 5.n of the TSO, if the equipment performs functions beyond those in paragraph 3
and paragraph 3.a.

3. Garmin was granted a deviation from TSO-C139 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from RTCA/DO-229D to use a 10 degree vertical viewing angle below the
lower display edge.

2. Garmin was granted a deviation from RTCA/DO-229D to use GPS antennas that meet Garmin minimum
performance specifications.

3. Garmin was granted a deviation from TSO-C146c to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C147 not to furnish each person receiving a GTN 725/750 copies of
the data in paragraphs 3(a)(10) through (12) of the TSO.

2. Garmin was granted a deviation from TSO-C147 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C151b Section 5.c(2) not to furnish each person receiving a GTN
725/750 copies of the data in paragraphs 5.a(11) through (13) of the TSO.

2. Garmin was granted a deviation from TSO-C151b to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1. Garmin was granted a deviation from TSO-C165 Section 5.c(2) not to furnish each person receiving a GTN
725/750 copies of the data in paragraphs 5.a(11) through (13) of the TSO.

2. Garmin was granted a deviation from TSO-C165 to mark product name, part number, serial number and a
statement on the unit’s nameplate label “TSO-C146c Class 3, See IM for Add’l Appliance Approvals ”, instead of
Product Type, TSO Numbers, Equipment Class, “Dev” (deviation), Environmental Categories, Date of
Manufacture, weight and Software Part Number.

1.5.3 FCC Grant of Equipment Authorization

Model FCC ID

GTN 750 IPH-01594

GTN 725/750 TSO Installation Manual Page 1-11
190-01007-02 Rev. A

1.6 Database Options and Updates

1.6.1 Navigation Database

The navigation database resides on a database card that is inserted in the card slot on the unit front panel.

The database is generated on periodic cycles from current Jeppesen data and converted to the format used
by the GTN products. The data conversion process is performed using software that is developed and
maintained under Garmin document control processes according to RTCA/DO-200A, Standards for
Processing Aeronautical Data.

The database can be updated by purchasing a database subscription from Jeppesen. The database updates
include either replacing or re-programming the database card and inserting the updated card in the left
card slot on the unit front panel. Contact Jeppesen at 800-621-5377 or www.jeppesen.com for more
information and instructions.

Contact Garmin for more information on databases available for the GTN.

1.6.2 TAWS/Terrain Database

The TAWS/Terrain database resides on a database card that is inserted in the card slot on the unit front
panel.

The TAWS/Terrain database which serves both functions of Terrain Awareness and Warning System
(TAWS) and the standard configured GTN providing terrain functionality is available for updating on
periodic cycles and is available from Garmin. TAWS/Terrain database updates can be accomplished by
replacing or reprogramming the database card and inserting the updated card in the card slot on the unit
front panel. The TAWS/Terrain database can be downloaded via the internet and the card programmed
using a USB programmer available from Garmin. Contact Garmin at 800-800-1020 or www.garmin.com
for more information or instructions.

1.7 Fault Detection and Exclusion (FDE)

The GTN unit, when installed as defined in this manual, complies with the requirements for GPS primary
means navigation in oceanic and remote airspace when used in conjunction with the FDE Prediction
program.

The GTN unit includes fault detection and exclusion (FDE), which is active for all flight phases including
oceanic and remote operations, en route and terminal, and precision and non-precision approaches, and
does not require any pilot interaction. The FDE consists of two parts:

1. The fault detection function detects a satellite failure that can affect navigation; and

2. The exclusion function is the capability to exclude one or more failed satellites and prevent them

from affecting navigation.

The FDE Prediction program is used to predict FDE availability. The FDE Prediction program must be
used prior to oceanic or remote area flights for all operators using the GTN unit as primary means
navigation under FAR parts 91, 121, 125, and 135.

Page 1-12 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

1.8 Limited Warranty

All Garmin avionics products are warranted to be free from defects in materials or workmanship for: two
years from the date of purchase for new Remote-Mount and Panel-Mount products; one year from the
date of purchase for new portable products and any purchased newly-overhauled products; six months for
newly-overhauled products exchanged through a Garmin Authorized Service Center; and 90 days for
factory repaired or newly-overhauled products exchanged at Garmin in lieu of repair. Within the
applicable 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 apply to: (i) cosmetic
damage, such as scratches, nicks and dents; (ii) consumable parts, such as batteries, unless product
damage has occurred due to a defect in materials or workmanship; (iii) damage caused by accident, abuse,
misuse, water, flood, fire, or other acts of nature or external causes; (iv) damage caused by service
performed by anyone who is not an authorized service provider of Garmin; or (v) damage to a product
that has been modified or altered without the written permission of Garmin. In addition, Garmin reserves
the right to refuse warranty claims against products or services that are obtained and/or used in
contravention of the laws of any country.

THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF
ALL OTHER WARRANTIES, WHETHER EXPRESS, 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 THE 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 (with a new or newly-overhauled replacement
product) the product 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.

Online Auction Purchases: Products purchased through online auctions are not eligible for warranty
coverage. 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.

International Purchases: A separate warranty may be provided by international distributors for devices
purchased outside the United States depending on the country. If applicable, this warranty is provided by
the local in-country distributor and this distributor provides local service for your device. Distributor
warranties are only valid in the area of intended distribution. Devices purchased in the United States or
Canada must be returned to the Garmin service center in the United Kingdom, the United States, Canada,
or Taiwan for service.

GTN 725/750 TSO Installation Manual Page 1-13
190-01007-02 Rev. A

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Page 1-14 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

2. INSTALLATION OVERVIEW

2.1 Introduction

Always follow acceptable avionics installation practices per AC 43.13-1B, AC 43.13-2B, or later FAA
approved revisions of these documents. The GPS/WAAS installation instructions have been prepared to
meet the guidance material contained in AC 20-138A “Airworthiness Approval of Global Navigation
Satellite System (GNSS) Equipment”. The communications installation instructions have been prepared
to meet the guidance material defined by AC 20-67B, “Airborne VHF Communications Equipment
Installations”.

2.2 Minimum System Configuration

2.2.1 VFR Installation

The minimum GTN installation requires the following items for a VFR Installation:

• GTN (installed in the aircraft manufacturer approved location for 6.25” wide avionics equipment)

• GPS antenna is required for GPS navigation functions.

• An external CDI is required for installations using the VOR navigation and glideslope

information.

• A NAV antenna is required for VHF NAV functions.

• A COM antenna is required for COM functions.

VFR installations must be placarded “GPS LIMITED TO VFR USE ONLY” in clear view of the pilot.

2.2.2 IFR GPS Installation

In order for the GTN to be utilized for IFR GPS Navigation, the criteria in Section 2.2.1 must be met in
addition to the following:

• An External CDI/HSI indicator must be installed in the pilot’s primary field-of-view (or in the

aircraft manufacturer approved mounting location). The indicator must have a vertical deviation
indicator (glideslope) in order to perform VNAV operations/approaches.

• Any annunciation required for Source Selection or IFR GPS Navigation must meet the acceptable

field-of-view requirements.

NOTE

To take full advantage of the GTN capabilities, an optional barometric altitude source is
recommended for automatic sequencing of fix-to-altitude (FA) and hold-to-altitude (HA)
leg types. If no barometric altitude data is provided to the GTN, FA and HA legs must be
manually sequenced.

GTN 725/750 TSO Installation Manual Page 2-1
190-01007-02 Rev. A

2.2.3 IFR VOR/LOC/GLIDESLOPE Installation

The minimum GTN unit installation requires the following items for an IFR VOR/LOC/GLIDESLOPE
installation:

• GTN (installed in the aircraft manufacturer approved location)

• GPS antenna, NAV antenna, and COM antenna.

• An External CDI/HSI indicator must be installed in the pilot’s primary field-of-view (or in the

aircraft manufacturer approved mounting location). The indicator must have a vertical deviation
indicator for glideslope and VNAV operations/approaches.

• Any annunciation required for Source Selection or IFR GPS Navigation must meet the acceptable

field-of-view requirements.

• A second GPS navigator, COM radio, or NAV radio must be installed.

2.3 External Sensors

When GTN is installed with external sensors, these sensors must be installed in accordance with the
manufacturer's data. This manual does not provide information for the installation of specific external
sensors.

The GTN can accept data from multiple altitude, heading, and baro correction sources. If multiple sources
are used, the GTN will accept data as described below.

NOTE

Barometric altitude is not required by the GTN to meet the requirements of TSO C146a.

2.3.1 Multiple Uncorrected Pressure Altitude Sources

The GTN can accept altitude from a RS-232 altitude encoder, fuel/air data computer (FADC),
ARINC 429 air data computer (ADC), ARINC 429 EFIS, and ARINC 429 traffic advisory system. If
multiple sources of altitude data are supplied to the GTN, only valid data from the highest priority source
is used (input priority cannot be configured). If the highest priority source becomes unavailable, data is
taken from the next-highest priority source. The priorities of the altitude sources are as follows (from
highest to lowest):

1. ARINC 429 ADC

2. ARINC 429 ADC/AHRS

3. ARINC 429 GDU

4. ARINC 429 EFIS/ADC

5. ARINC 429 Data Concentrator

6. ARINC 429 Traffic Advisory System

7. RS-232 Shadin Fuel and ADC

8. RS-232 Shadin Altitude or Icarus Altitude

Page 2-2 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02

2.3.2 Multiple Baro-Corrected Altitude Sources

The GTN unit can accept baro-corrected altitude from multiple ARINC 429 and RS-232 sources.

If multiple sources of baro-corrected altitude data are supplied to the GTN, only valid data from the
highest priority source is used. If the highest priority source becomes unavailable, data is taken from the
next-highest priority source. The priorities of the baro-corrected altitude sources are as follows from
highest to lowest:

1. ARINC 429 label 204 from Airdata

2. ARINC 429 label 204 from Garmin GDU

3. ARINC 429 label 204 from EFIS/Airdata

4. ARINC 429 label 204 from Data Concentrator

5. RS-232 bus from Shadin Fuel and Air Data Computer

2.3.3 Multiple Heading Sources

The GTN unit can accept heading data from multiple ARINC 429, RS-232, and Synchro sources. If
multiple sources of heading data are supplied to the GTN, only valid data from the highest priority source
is used. If the highest priority source becomes unavailable, data is taken from the next-highest priority
source. The priorities of the heading sources are as follows from highest to lowest:

1. ARINC 429 label 314 from EFIS or Honeywell EFIS

2. ARINC 429 label 320 from EFIS or Honeywell EFIS, corrected for local magnetic variation

3. ARINC 429 label 320 from EFIS/Airdata, corrected for local magnetic variation

4. ARINC 429 label 320 from Garmin GDU, corrected for local magnetic variation

5. ARINC 429 label 314 from INS/IRU

6. ARINC 429 label 314 from Data Concentrator

7. ARINC 429 label 320 from INS/IRU, corrected for local magnetic variation

8. ARINC 429 label 320 from Airdata/AHRS, corrected for local magnetic variation

9. ARINC 429 label 320 from Garmin GAD 42, corrected for local magnetic variation

10. ARINC 429 label 320 from Sandel EHSI, corrected for local magnetic variation

11. ARINC 429 label 314 from GAD 42

12. XYZ Synchro

13. ARINC 429 label 320 from Data Concentrator

14. ARINC 429 label 320 from Traffic Advisory, corrected for local magnetic variation

15. RS-232 bus from Shadin Fuel and Air Data Computer

16. RS-232 bus from WX-500

GTN 725/750 TSO Installation Manual Page 2-3
190-01007-02 Rev. A

2.3.4 Multiple Indicated Airspeed Sources

The GTN unit can accept indicated airspeed data from multiple ARINC 429 and RS-232 sources. If
multiple sources of indicated airspeed data are supplied to the GTN, only valid data from the highest
priority source is used. If the highest priority source becomes unavailable, data is taken from the next­highest priority source. The priorities of the indicated airspeed sources are as follows from highest to
lowest:

1. ARINC 429 label 206 from Garmin GDU

2. ARINC 429 label 206 from Airdata/AHRS

3. ARINC 429 label 206 from Data Concentrator

4. RS-232 bus from Shadin Fuel and Air Data Computer

2.3.5 Multiple True Airspeed Sources

The GTN unit can accept heading data from multiple ARINC 429 and RS-232 sources. If multiple
sources of true airspeed data are supplied to the GTN, only valid data from the highest priority source is
used. If the highest priority source becomes unavailable, data is taken from the next-highest priority
source. The priorities of the true airspeed sources are as follows from highest to lowest:

1. ARINC 429 label 210 from Airdata

2. ARINC 429 label 210 from Airdata/AHRS

3. ARINC 429 label 210 from Garmin GDU

4. ARINC 429 label 210 from EFIS/Airdata

5. ARINC 429 label 210 from Garmin GAD 42

6. ARINC 429 label 210 from Data Concentrator

7. RS-232 bus from Shadin Fuel and Air Data Computer

2.3.6 Multiple VLOC Course Select Sources

The GTN unit can accept VLOC course select data from the sources list below. If multiple sources of
VLOC course select data are supplied to the GTN, only valid data from the highest priority source is used.
If the highest priority source becomes unavailable, data is taken from the next-highest priority source. The
priorities of the VLOC course select sources are as follows from highest to lowest:

1. ARINC 429 label 100 from Sandel EHSI

2. ARINC 429 label 110 from Garmin GAD 42

3. TO/FROM course from the appliance’s Omni-Bearing Selector (OBS) control

Page 2-4 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02