GMC 605

Installation Manual

190-01488-01 November, 2023 Revision 12

 © 2023
Garmin Ltd. or its subsidiaries
All Rights Reserved
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1200 E. 151st Street
Olathe, KS 66062 USA
Garmin (Europe) Ltd.
Liberty House, Hounsdown Business Park
Southampton, Hampshire SO40 9LR U.K.

Garmin aviation support and warranty information is available at garmin.com/aviationwarranty.

RECORD OF REVISIONS

Revision
Revision Description
Date
8 02/09/21 Updated configuration mode info
9 04/09/21 Corrected measurements in Table 1-2 Physical Characteristics
10 05/02/22 Corrected pin layout in Figure 4-2
11 11/08/23 Updated Configuration info and various updates
12 11/16/23 Added color display unit info

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 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. The preceding statement is required to be included on any and all
reproductions in whole or in part of this manual.

CURRENT REVISION DESCRIPTION

Page Section
Revision Description of Change
Number(s) Number
ii Front Added note regarding color display units
1-1–1-3,
1-6–1-9, 1 Added color display unit info throughout Section 1
1-11, 1-13
Updated GMC 605 part numbers Table 2-1 per color display
2-1 2.2
units
3-13–3-16,
3-18–3-24,
3.10.1.1 Updated configuration info per color display units
3-27, 3-30,
12 3-32
3-35–3-37,
3.10.2 Updated post install cal procedures per color display units
3-39–3-41
Added note regarding screenshots and updated captions in
3-45 3.11.2
Figures 3-27 & 3-28 to specify monochrome display units
Added note regarding screenshots and updated caption in
3-47 3.11.3
Figure 3-29 to specify monochrome display unit
3-48 3.12 Updated data log download info per color display units
3-49 3.13 Added Figure 3-32 for color display unit
4-15 4.17.1 Added note regarding ARINC In ports.

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 DEFINITIONS OF WARNINGS, CAUTIONS, AND NOTES

NOTE
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.

NOTE
Throughout this document, references made to GMC 605 apply equally to the GMC 605H
unless specifically noted otherwise.

NOTE
The GMC 605 units are available with a monochrome or a color display. Details and
specifications are provided for both unit types and are identified accordingly in this
manual.

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 SOFTWARE LICENSE AGREEMENT
BY USING THE DEVICE, COMPONENT OR SYSTEM MANUFACTURED OR SOLD BY GARMIN
(“THE GARMIN PRODUCT”), YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS
OF THE FOLLOWING SOFTWARE LICENSE AGREEMENT. PLEASE READ THIS AGREEMENT
CAREFULLY. Garmin Ltd. and its subsidiaries (“Garmin”) grants you a limited license to use the
software embedded in the Garmin Product (the “Software”) in binary executable form in the normal
operation of the Garmin Product. Title, ownership rights, and intellectual property rights in and to the
Software remain with Garmin and/or its third-party providers. You acknowledge the Software is the
property of Garmin and/or its third-party providers and is protected under the United States of America
copyright laws and international copyright treaties. You further acknowledge the structure, organization,
and code of the Software are valuable trade secrets of Garmin and/or its third-party providers and the
Software in source code form remains a valuable trade secret of Garmin and/or its third-party providers.
You agree not to reproduce, decompile, disassemble, modify, reverse assemble, reverse engineer, or
reduce to human readable form the Software or any part thereof or create any derivative works based on
the Software. You agree not to export or re-export the Software to any country in violation of the export
control laws of the United States of America.

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 TABLE OF CONTENTS

PARAGRAPH PAGE

Section 1 General Description ...........................................................................1-1

1.1 Introduction...................................................................................................................... 1-1
1.2 Equipment Description .................................................................................................... 1-1
1.3 Interface Summary........................................................................................................... 1-5
1.4 Technical Specifications .................................................................................................. 1-6
1.5 Certification ................................................................................................................... 1-10
1.6 Limitations ..................................................................................................................... 1-12
1.7 Operating Instructions.................................................................................................... 1-13
1.8 Reference Documents .................................................................................................... 1-15

Section 2 Installation Overview .........................................................................2-1

2.1 Introduction...................................................................................................................... 2-1
2.2 Installation Materials ....................................................................................................... 2-1
2.3 Equipment Available ....................................................................................................... 2-1
2.4 Installation Considerations and Data Prioritization ......................................................... 2-3
2.5 Cabling & Wiring ............................................................................................................ 2-4
2.6 Electrical Bonding ........................................................................................................... 2-4
2.7 Cooling Air ...................................................................................................................... 2-4
2.8 Mounting Requirements .................................................................................................. 2-5

Section 3 Installation Procedure........................................................................3-1

3.1 Unpacking Unit................................................................................................................ 3-1
3.2 Wiring Harness Installation ............................................................................................. 3-1
3.3 Backshell Assembly......................................................................................................... 3-2
3.4 Garmin Air Data Module (ADM) Installation ................................................................. 3-2
3.5 Configuration Module Installation................................................................................... 3-4
3.6 Collective Position Sensor Installation (Rotorcraft Only) ............................................... 3-4
3.7 Garmin Magnetometer Installation (Rotorcraft Only)..................................................... 3-7
3.8 Equipment Rack Installation............................................................................................ 3-8
3.9 Unit Installation ............................................................................................................... 3-9
3.10 Post Installation Configuration & Checkout................................................................ 3-10
3.11 Software Loading......................................................................................................... 3-44
3.12 Data Log Download..................................................................................................... 3-48
3.13 Assert Log Download .................................................................................................. 3-49
3.14 Continued Airworthiness ............................................................................................. 3-49

Section 4 System Interconnects .........................................................................4-1

4.1 Connector Description ..................................................................................................... 4-1
4.2 Pin List ............................................................................................................................. 4-1
4.3 Aircraft Power.................................................................................................................. 4-6

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PARAGRAPH PAGE

4.4 Analog Inputs................................................................................................................... 4-6

4.5 Excitation Outputs ........................................................................................................... 4-8
4.6 Audio Output ................................................................................................................... 4-8
4.7 CAN Bus.......................................................................................................................... 4-9
4.8 Configuration Module (Serial Input/Output) ................................................................... 4-9
4.9 Discrete Inputs, Configurable ........................................................................................ 4-10
4.10 Discrete Inputs, Active High ....................................................................................... 4-11
4.11 Discrete Outputs .......................................................................................................... 4-11
4.12 Ethernet ........................................................................................................................ 4-12
4.13 Flight Director Analog Outputs ................................................................................... 4-13
4.14 GPS PPS (Pulse Per Second) ....................................................................................... 4-13
4.15 Lighting Bus ................................................................................................................ 4-14
4.16 Navigation Analog Interfaces ...................................................................................... 4-14
4.17 Serial Data.................................................................................................................... 4-15
4.18 Power Out .................................................................................................................... 4-17

Appendix A Outline & Installation Drawings.................................................A-1

Appendix B Interconnect Drawings.................................................................B-1

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 LIST OF FIGURES
FIGURE PAGE

Section 1 General Description ...........................................................................1-1

Figure 1-1 GMC 605 Autopilot Mode Controller/Flight Director Computer
(011-02967-02) ...................................................................................................................... 1-2
Figure 1-2 GMC 605 Autopilot Mode Controller/Flight Director Computer
(Black Fixed Wing, IAS Button, 011-02967-12) .................................................................. 1-2
Figure 1-3 GMC 605 Autopilot Mode Controller/Flight Director Computer
(Gray Fixed Wing, FLC Button 011-02967-14) .................................................................... 1-3
Figure 1-4 GMC 605 Autopilot Mode Controller/Flight Director Computer
(Black Fixed Wing, FLC Button, 011-02967-16).................................................................. 1-3
Figure 1-5 GMC 605H Mode Controller/Computer for Rotorcraft (with external
Flight Director support) (011-02967-20) ............................................................................... 1-3
Figure 1-6 GMC 605H Mode Controller/Computer for Rotorcraft (no external Flight
Director support) (011-02967-22) ......................................................................................... 1-4
Figure 1-7 GMC 605H Mode Controller/Computer for Rotorcraft (no Trim Wheel)
(011-02967-24) ...................................................................................................................... 1-4

Section 2 Installation Overview .........................................................................2-1

Figure 2-1 GMC 605 Install Rack (115-01918-10) .............................................................. 2-5

Section 3 Installation Procedure........................................................................3-1

Figure 3-1 Attachment of ADM to Rear Connector Plate .................................................... 3-3
Figure 3-2 Configuration Mode Start-Up Screen (monochrome display unit)................... 3-12
Figure 3-3 Configuration Pages Block Diagram ................................................................ 3-13
Figure 3-4 Sys/Status Configuration Page (monochrome display unit) ............................. 3-14
Figure 3-5 Sys/Status Configuration Page (color display unit) .......................................... 3-14
Figure 3-6 Prod/Main Board Configuration Page (monochrome display units) ................ 3-18
Figure 3-7 Prod/Main Board Configuration Page (color display units) ............................. 3-18
Figure 3-8 Manifest Page, Pass Indication (monochrome display units) ........................... 3-19
Figure 3-9 Manifest Page, Fail Indication (monochrome display units) ............................ 3-19
Figure 3-10 Manifest Page, Pass Indication (color display units) ...................................... 3-20
Figure 3-11 Manifest Page, Fail Indication (color display units) ....................................... 3-20
Figure 3-12 Piecewise Graph GMC DSP/Backlight Configuration Page
(monochrome display units) ................................................................................................ 3-21
Figure 3-13 Piecewise Graph GMC DSP/Backlight Configuration Page
(color display units) ............................................................................................................. 3-21
Figure 3-14 GMC DSP/Photocell Configuration Page (monochrome display units)......... 3-22
Figure 3-15 GMC DSP/Photocell Configuration Page (color display units)...................... 3-22
Figure 3-16 Piecewise Graph Remote DSP/Backlight Configuration Page
(monochrome display units) ................................................................................................ 3-24
Figure 3-17 Piecewise Graph Remote DSP/Backlight Configuration Page
(color display units) ............................................................................................................. 3-24

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FIGURE PAGE

Figure 3-18 GFC/AHRS Configuration Page (monochrome display units)....................... 3-27

Figure 3-19 GFC/AHRS Configuration Page (color display units).................................... 3-27
Figure 3-20 GFC/RIGGING Configuration Page............................................................... 3-28
Figure 3-21 I/O/RS-232 Configuration Page (monochrome display units)........................ 3-30
Figure 3-22 I/O/RS-232 Configuration Page (color display units)..................................... 3-30
Figure 3-23 Test/Audio Configuration Page ...................................................................... 3-32
Figure 3-24 Test/Audio Configuration Page ...................................................................... 3-32
Figure 3-25 Helicopter Position Examples ......................................................................... 3-37
Figure 3-26 Test Servo Page............................................................................................... 3-39
Figure 3-27 Standard or Select Load Page (monochrome display unit)............................. 3-45
Figure 3-28 SW Upload Results Page (monochrome display unit).................................... 3-45
Figure 3-29 Start Load Page (monochrome display unit)................................................... 3-47
Figure 3-30 A-B Sys/Data Logs Configuration Page (monochrome display unit)............. 3-48
Figure 3-31 A-B Sys/Data Logs Configuration Page (color display unit) ......................... 3-48
Figure 3-32 Asserts Page (color display unit) .................................................................... 3-49

Section 4 System Interconnects .........................................................................4-1

Figure 4-1 Rear View of Backplate ...................................................................................... 4-1
Figure 4-2 Rear Connectors J6051 & J6052, Viewed from Back of Unit............................ 4-1

Appendix A Outline & Installation Drawings ................................................A-1

Figure A-1 Outline Drawing................................................................................................ A-1
Figure A-2 Installation Drawing.......................................................................................... A-2
Figure A-3 Panel Cutout Drawings ..................................................................................... A-3

Appendix B Interconnect Drawings ................................................................B-1

Figure B-1 Power, Lighting Bus, GI 285 Interconnect Drawing Example ..........................B-1
Figure B-2 Config Module, Alt Enc, GNS™ 430W Receiver Interconnect
Drawing Example ..................................................................................................................B-2
Figure B-3 Audio Output Interconnect Drawing Example...................................................B-3
Figure B-4 Configuration Discrete Inputs Interconnect Drawing Example .........................B-4
Figure B-5 Rotorcraft Only Configuration Discrete Inputs Interconnect
Drawing Example ..................................................................................................................B-5
Figure B-6 GSA 87 Interconnect Drawing Example............................................................B-6
Figure B-7 GFS 83 Interconnect Drawing Example ............................................................B-7
Figure B-8 ARINC 429 Roll Steering Interconnect Drawing Example ...............................B-8
Figure B-9 GPS Source Interconnect Drawing Example .....................................................B-9
Figure B-10 Ethernet Interconnect Drawing Example .......................................................B-10
Figure B-11 Garmin Air Data Interconnect Drawing Example..........................................B-11
Figure B-12 Stall Warning, Flap Extend/Retract Interconnect Drawing Example ............B-12
Figure B-13 Position Sensor Wiring Interconnect Drawing Example ...............................B-13
Figure B-14 Radar Altimeter Interconnect Drawing Example ...........................................B-14

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 LIST OF TABLES
TABLE PAGE

Section 1 General Description ...........................................................................1-1

Table 1-1 Interface Summary ............................................................................................... 1-5
Table 1-2 Physical Characteristics GMC 605 Monochrome Display Unit (011-02967-02) and
GMC 605H (011-02967-20/-22/-24) ..................................................................................... 1-6
Table 1-3 Physical Characteristics GMC 605 Color Display Unit
(011-02967-12/-14/-16) ......................................................................................................... 1-6
Table 1-4 General Specifications GMC 605 Monochrome Display Unit
(011-02967-02) and GMC 605H (011-02967-20/-22/-24) .................................................... 1-7
Table 1-5 General Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16).. 1-7
Table 1-6 Power Specifications GMC 605 Monochrome Display Unit
(011-02967-02) and GMC 605H (011-02967-20/-22/-24) .................................................... 1-8
Table 1-7 Power Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16) .... 1-8
Table 1-8 Display Specifications GMC 605 Monochrome Display Units (011-02967-02)
and GMC 605H (011-02967-20/-22/-24) .............................................................................. 1-9
Table 1-9 Display Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16) .. 1-9
Table 1-10 Position Sensor Specifications ......................................................................... 1-10
Table 1-11 GMC 605 (011-02967-02, 011-02967-1( ), 011-02967-2( ))
TSO Compliance.................................................................................................................. 1-11
Table 1-12 GMC 605 (011-02967-02, 011-02967-1( ), 011-02967-2( ))
TSO Deviations.................................................................................................................... 1-12
Table 1-13 Lever Arm Distances........................................................................................ 1-12
Table 1-14 Reference Documents....................................................................................... 1-15

Section 2 Installation Overview .........................................................................2-1

Table 2-1 GMC 605 Catalog Part Numbers ......................................................................... 2-1
Table 2-2 Equipment Available ............................................................................................ 2-1
Table 2-4 Potted Configuration Module Kit Contents (011-00979-03) ............................... 2-2
Table 2-5 GMC 605 Backplate Kit Contents (011-03295-10) ............................................. 2-2
Table 2-6 GMC 605 Connector Kit Contents (011-03296-00)............................................. 2-2
Table 2-3 Accessories Required But Not Provided .............................................................. 2-2
Table 2-8 String Pot, Connector Kit Contents (011-05126-00)............................................ 2-3
Table 2-9 Data Priority ......................................................................................................... 2-3
Table 2-7 GMC 605 Air Data Module (w/Kit) Contents (011-04426-00) ........................... 2-3

Section 3 Installation Procedure........................................................................3-1

Table 3-1 Pin Contact Part Numbers .................................................................................... 3-1
Table 3-2 Recommended Crimp Tools................................................................................. 3-1
Table 3-3 Air Data Module Inputs and Outputs ................................................................... 3-2
Table 3-4 Collective Position Sensor Inputs and Outputs (ANALOG 1 option) ................. 3-5
Table 3-5 Collective Position Sensor Inputs and Outputs (ANALOG 2 option) ................. 3-5
Table 3-6 Magnetometer Inputs............................................................................................ 3-7

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TABLE PAGE

Table 3-7 Required Equipment ......................................................................................... 3-10

Table 3-8 GMC 605 Installation Key Functions by Model ................................................ 3-11
Table 3-9 Configuration Mode Navigation ........................................................................ 3-12
Table 3-10 Sys/Status Selections ........................................................................................ 3-15
Table 3-11 Install Selections............................................................................................... 3-16
Table 3-12 Manifest Page Selections.................................................................................. 3-19
Table 3-13 Backlight Source Selections ............................................................................. 3-21
Table 3-14 Backlight Source Selections ............................................................................. 3-25
Table 3-15 Status ................................................................................................................ 3-28
Table 3-16 Selectable Command ........................................................................................ 3-29
Table 3-17 Post-Installation Calibration Procedure Summary ........................................... 3-33
Table 3-18 Slip Clutch Test Unavailable Conditions ......................................................... 3-42
Table 3-19 Slip Clutch Test Error Conditions .................................................................... 3-43

Section 4 System Interconnects .........................................................................4-1

Table 4-1 J6051 Pin Assignments ........................................................................................ 4-1
Table 4-2 J6052 Pin Assignments ........................................................................................ 4-4
Table 4-3 Aircraft Power ...................................................................................................... 4-6
Table 4-4 Analog Inputs ....................................................................................................... 4-7
Table 4-5 Excitation Outputs ................................................................................................ 4-8
Table 4-6 Audio Out ............................................................................................................. 4-8
Table 4-7 CAN Bus .............................................................................................................. 4-9
Table 4-8 Configuration Module .......................................................................................... 4-9
Table 4-9 Discrete Inputs.................................................................................................... 4-10
Table 4-10 Discretes In, Active Hi ..................................................................................... 4-11
Table 4-12 Discrete Outputs ............................................................................................... 4-12
Table 4-13 Ethernet ............................................................................................................ 4-12
Table 4-11 Discrete Output Formats .................................................................................. 4-12
Table 4-14 Flight Director Analog Outputs........................................................................ 4-13
Table 4-15 GPS PPS ........................................................................................................... 4-13
Table 4-16 Lighting Bus ..................................................................................................... 4-14
Table 4-17 Navigation Analog Interfaces........................................................................... 4-14
Table 4-18 ARINC 429....................................................................................................... 4-15
Table 4-19 Receiver Comments ......................................................................................... 4-16
Table 4-20 RS-232.............................................................................................................. 4-16
Table 4-21 RS-485.............................................................................................................. 4-17
Table 4-22 Power Out......................................................................................................... 4-17

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1 GENERAL DESCRIPTION
1.1 Introduction
This manual is intended to provide mechanical and electrical information for use in the planning and
design of an installation of the Garmin GMC 605 into an aircraft. This manual is not a substitute for an
approved airframe-specific maintenance manual, installation design drawing, or complete installation data
package. Attempting to install equipment by reference to this manual alone and without first planning or
designing an installation specific to your aircraft may compromise your safety and is not recommended.
The content of this manual assumes use by competent and qualified avionics engineering personnel and/or
avionics installation specialists using standard aviation maintenance practices in accordance with Title 14
of the Code of Federal Regulations and other relevant accepted practices. This manual is not intended for
use by individuals who do not possess the competencies and abilities set forth above.

NOTE
Garmin recommends installation of the GMC 605 by a Garmin-authorized installer. To
the extent allowable by law, Garmin will not be liable for damages resulting from
improper or negligent installation of the GMC 605. For questions, please contact Garmin
Product Support at 1-888-606-5482.

1.2 Equipment Description

The GMC 605 is a panel-mounted Line Replaceable Unit (LRU) that provides automatic flight guidance
computation, control, and display functions for a Garmin Automatic Flight Control System (AFCS). The
GMC 605 mounts flush to the instrument panel or radio console in a tray that includes captive connectors.
GMC 605H refers to GMC 605 models that address the needs of rotorcraft pilots. These models
(Figure 1-5, Figure 1-6, and Figure 1-7) use green backlighting that is commonly seen in helicopter night
operations. The operation of the engagement buttons, annunciators, and remote discrete switches were
developed for rotorcraft operation. The GMC 605H shares connector pin definitions with the fixed wing
GMC 605. Unless otherwise noted, all content applies to both the fixed wing and rotorcraft models of the
GMC 605 family. The GMC 605 is also available with a color display. Where there are differences in
behavior between the monochrome and color units, separate content is provided for each.
The user interface consists of backlit mode selection keys, annunciators, a wheel to adjust pitch flight
director references, and a backlit LCD to display active and armed modes, reference values, alerts, and
messages.
Flight director mode logic as well as some autopilot management functions are performed within the
GMC 605 main processor.
The GMC 605 contains internal sensors which compute pitch, roll, and yaw attitude and rates. These
internal sensors are capable of following maneuvers through a range of 360º in bank and pitch. The
rotation rate capability is 250 º/s. Independent monitors within the GMC can disconnect the autopilot if
errors are detected, allowing the GMC 605 to operate without any external Attitude Heading Reference
System (AHRS) interface. An Air Data Module (ADM) can optionally be mounted on the GMC tray and
connected to the aircraft pitot-static system to support a pressure altitude hold (ALT), vertical speed (VS),
and Indicated Airspeed (IAS) modes when there is no external air data computer (ADC) interface
available.

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The GMC 605 has extensive I/O capabilities that support interfaces to a large variety of equipment found
in fielded aircraft. When interfaced to a Garmin Primary Flight Display (PFD), a high speed Ethernet
connection provides efficient data transfer between the display unit (GDU™ display) and GMC with
minimal wiring required.
The GMC 605 features a covered micro USB port on the front face of the unit, allowing a convenient
means of updating software or configuration and downloading diagnostic information to aid in
troubleshooting.
For fixed wing installations that do not receive magnetometer measurements directly, magnetic field
unsuitability near the Earth’s poles does not degrade operation of the GMC 605. The GMC 605 has an
internal AHRS, which does not rely on magnetic field readings from a magnetometer, and does not require
recurrent magnetic field model updates.
In contrast, the GMC 605H rotorcraft installations require magnetometer measurements to improve AHRS
performance during uncoordinated maneuvers. The internal AHRS for the GMC 605H is affected by
magnetic field unsuitability near the Earth’s poles, and does require magnetic field model updates. It also
requires a magnetometer calibration step as part of its installation process. See Section 1.6 for further
details.

Figure 1-1 GMC 605 Autopilot Mode Controller/Flight Director Computer

(011-02967-02)

Figure 1-2 GMC 605 Autopilot Mode Controller/Flight Director Computer

(Black Fixed Wing, IAS Button, 011-02967-12)

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 Figure 1-3 GMC 605 Autopilot Mode Controller/Flight Director Computer
(Gray Fixed Wing, FLC Button 011-02967-14)

Figure 1-4 GMC 605 Autopilot Mode Controller/Flight Director Computer

(Black Fixed Wing, FLC Button, 011-02967-16)

Figure 1-5 GMC 605H Mode Controller/Computer for Rotorcraft (with external Flight
Director support) (011-02967-20)

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 Figure 1-6 GMC 605H Mode Controller/Computer for Rotorcraft (no external Flight
Director support) (011-02967-22)

Figure 1-7 GMC 605H Mode Controller/Computer for Rotorcraft (no Trim Wheel)
(011-02967-24)

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1.3 Interface Summary
Table 1-1 provides a summary of the types of interfaces supported by the GMC 605. For more detailed
information see the Pin Function List in Section 4.

Table 1-1 Interface Summary

Type Interfacing Equipment
ARINC 429 Input Air Data Computer, GPS Roll Steering, Radar Altimeter, configurable interfaces
Analog Audio Out Audio Panel, Unswitched/Unmuted Alert
Analog Input Course Deviation Left/Right, Glideslope Deviation Up/Down, Lateral Flag,
Vertical Flag, Course Error, Heading Error, Dimmer (5VAC, or 5/14/28 VDC),
Directional Gyro Heading (400/5000 Hz), Collective Lever Sensor
Analog Output Flight Director Left/Right/Up/Down, Directional Gyro Heading
(400/5000 Hz excitation), Collective Lever Sensor excitation
CAN Garmin Force Trim Servos (GFS)
Configuration Serial Garmin Air Data Module (ADM) or Garmin Configuration Module
Input/Output
Discrete Input Stall Warn, Flaps-in-Motion, Go Around (GA), Control Wheel Steering (CWS),
Trim Arm, Trim Up/Down, Autopilot Disconnect, Approach Mode. See STC
Installation Manual for additional details.
Discrete Output FD Valid, Sonalert
HSDB (High Speed Garmin Display Unit (GDU), Garmin Touchscreen Navigator (GTN™ avionics)
Ethernet)
PPS Input GPS Time Mark (from GTN, GNS™-W receiver, or GTX™ 3X5 transponder with
GPS Option)
RS-232 Input GI 285 Remote Annunciator, MapMx GPS Data (from GTN, GNS-W, or GTX
3X5 with GPS Option)
RS-232 Output GI 285 Remote Annunciator
RS-485 In/Out Garmin autopilot servos (GSA), Garmin trim adapter (GTA), or Input only from
Garmin magnetometer (GMU)

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1.4 Technical Specifications
1.4.1 Environmental Qualification Form
It is the responsibility of the installing agency to obtain the latest revision of the GMC 605 Environmental
Qualification Form. This form is available directly from Garmin under the following part number:
GMC 605 Environmental Qualification Form, Garmin part number 005-00747-03
To obtain a copy of this form, see the dealer/OEM portion of the Garmin web site (www.garmin.com).
1.4.2 Physical Characteristics

Table 1-2 Physical Characteristics GMC 605 Monochrome Display Unit (011-02967-02) and
GMC 605H (011-02967-20/-22/-24)

Characteristics Specifications
Width (behind panel) 6.30 inches (16. 0 cm)
Bezel Width 6.25 inches (15.9 cm)
Height (behind panel) 1.625 inches (4.1 cm)
Bezel Height 1.65 inches (4.2 cm)
Depth (behind panel) w/Air Data Module 9.61 inches (24.4 cm)
Depth (behind panel) w/Connector Kit 9.61 inches (24.4 cm)
Unit Weight w/out Connector Kit 2.19 lbs (0.99 kg)
Weight, Unit w/Connector Kit and Air Data Module 2.91 lbs (1.32 kg)
Install Rack Weight 0.34 lbs (0.15 kg)

Table 1-3 Physical Characteristics GMC 605 Color Display Unit (011-02967-12/-14/-16)

Characteristics Specifications
Width (behind panel) 6.30 inches (16. 0 cm)
Bezel Width 6.25 inches (15.9 cm)
Height (behind panel) 1.625 inches (4.1 cm)
Bezel Height 1.65 inches (4.2 cm)
Depth (behind panel) w/Air Data Module 9.61 inches (24.4 cm)
Depth (behind panel) w/Connector Kit 9.61 inches (24.4 cm)
Unit Weight w/out Connector Kit 2.28 lbs (1.03 kg)
Weight, Unit w/Connector Kit and Air Data Module 3.00 lbs (1.36 kg)
Install Rack Weight 0.34 lbs (0.15 kg)

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1.4.3 General Specifications
Table 1-4 and Table 1-5 contain general specifications.
Table 1-4 General Specifications GMC 605 Monochrome Display Unit (011-02967-02) and
GMC 605H (011-02967-20/-22/-24)

Characteristics Specifications
Operating Temperature Range* -40ºC to +70ºC (-40º F to +158º F)
Humidity 95% non-condensing
Maximum Operating Altitude, GMC 605 only 55,000 ft
Maximum Operating Altitude, GMC 605 w/Air Data Module 30,000 ft
Maximum Operating Airspeed, GMC 605 w/Air Data Module 300 kts
Software Compliance RTCA/DO-178B Level A, B, C, D, E
Hardware Compliance RTCA/DO-254 Level A
Environmental Compliance RTCA/DO-160F
Maximum Days of Continuous Operation 49
*Warm equipment to -30ºC (-22ºF) if Air Data Module experiences temperatures below -40ºC (-40ºF) for
prolonged periods. For more details, see the Environmental Qualification Form (Section 1.4.1)

Table 1-5 General Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16)

Characteristics Specifications
Operating Temperature Range* -40ºC to +55ºC (-40º F to +131º F)
Humidity 95% non-condensing
Maximum Operating Altitude, GMC 605 only 55,000 ft
Maximum Operating Altitude, GMC 605 w/Air Data Module 30,000 ft
Maximum Operating Airspeed, GMC 605 w/Air Data Module 300 kts
Software Compliance RTCA/DO-178B Level A, B, C, D, E
Hardware Compliance RTCA/DO-254 Level A
Environmental Compliance RTCA/DO-160F
Maximum Days of Continuous Operation 49
*Warm equipment to -30ºC (-22ºF) if Air Data Module experiences temperatures below -40ºC (-40ºF) for
prolonged periods. For more details, see the Environmental Qualification Form (Section 1.4.1)

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1.4.4 Power Specifications

Table 1-6 Power Specifications GMC 605 Monochrome Display Unit (011-02967-02) and
GMC 605H (011-02967-20/-22/-24)

Power Consumption* Specifications

Average Current Draw 14 Vdc 0.53 A
Maximum Current Draw 14Vdc 1.15 A
Average Current Draw 28 Vdc 0.27 A
Maximum Current Draw 28Vdc 0.70 A
*14/28 Vdc. See the Environmental Qualification Form for details on surge ratings and minimum/
maximum operating voltages.

Table 1-7 Power Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16)

Power Consumption* Specifications

Average Current Draw 14 Vdc 0.76 A
Maximum Current Draw 14Vdc 1.33 A
Average Current Draw 28 Vdc 0.38 A
Maximum Current Draw 28Vdc 0.79 A
*14/28 Vdc. See the Environmental Qualification Form for details on surge ratings and minimum/
maximum operating voltages.

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1.4.5 Display Specifications

Table 1-8 Display Specifications GMC 605 Monochrome Display Units (011-02967-02) and
GMC 605H (011-02967-20/-22/-24)

Characteristic Specifications
Width: 3.46 inches (88.0 mm)
Display Size
Height: 0.843 inches (21.4 mm)
Width: 2.95 inches (74.98 mm)
Active Area
Height: 0.486 inches (12.36 mm)
Resolution 200 x 33 pixels
Left: 45°
Right: 45°
Viewing Angles (direction of pilot’s viewing angle)
From Top: 30°
From Bottom: 10°

Table 1-9 Display Specifications GMC 605 Color Display Unit (011-02967-12/-14/-16)

Characteristic Specifications
Display Size 3.2 inches (81.3 mm) diagonal
Width: 3.06 inches (77.76 mm)
Active Area
Height: 0.79 inches (20.00 mm)
Resolution 480 x 124 pixels
Left: 45°
Right: 45°
Viewing Angles (direction of pilot’s viewing angle)
From Top: 30°
From Bottom: 10°

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1.4.6 Position Sensor Specifications
The Position Sensor accessory measuring Collective Lever operation, Garmin 011-04817-00, has the
following characteristics. The Sensor is driven with a 2500 Hz 7 VRMS A/C signal.

Table 1-10 Position Sensor Specifications

Characteristic Specifications
Sensor Type Potentiometer
Resistance 5 kΩ ± 10%
Independent Linearity Error ±0.5% maximum
Power Rating 1.0 W (70 °C)
Cable Tension Range (Normal Operation) 1.5 to 12 oz (0.4 to 3.3 N)
Minimum Cable Breaking Strength 40 lb (177 N)

1.5 Certification
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
find 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 if performed under 14 CFR part
43 or the applicable airworthiness requirements. This is an incomplete system intended to provide the
functions identified in, and when installed according to the installation manual.
The Appliance Project Identifier (API) for the GMC 605 and the GMC 605H is GMN-01075. The API has
been used for project identification with the FAA.
The GMC 605 and GMC 605H are designed to support a failure condition classification of Catastrophic for
autopilot operation.

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1.5.1 GMC 605 TSO Compliance
Table 1-11 lists the applicable TSO for the GMC 605.
Table 1-11 GMC 605 (011-02967-02, 011-02967-1( ), 011-02967-2( )) TSO Compliance
Boot Block
Class System Software Part CLD Part
Function Model TSO Class Software Part
Description Numbers Numbers
Numbers
RTCA DO-178B Level A:
Autopilot for Fixed 006-B1838-02 through
A1
Wing Airplane 006- B1838-1( )
RTCA DO-178B Level A, B, C, D: RTCA DO-178B Level A:
GMC 605 006-B2071-0( ) 006-B2071-B( )
Monochrome 006-B1838-B( ) RTCA DO-254 Level A:
TSO-C198 RTCA DO-178B Level E:
Fixed Wing 006-C0164-0( )
B Yaw Damper 006-B2071-T( ) RTCA DO-178B Level B:
011-02967-02
RTCA DO-178B Level B: 006-B2029-B( )
006-B2029-0( )
RTCA DO-178B Level E:
C Flight Director
006-B2029-5( )

RTCA DO-178B Level A:

006- B1838-1( )
Autopilot for Fixed
A1 RTCA DO-178B Level A, B, C, D:
Wing Airplane
006-B4421-0( )
RTCA DO-178B Level E: RTCA DO-178B Level A:
GMC 605 006-B4421-T( ) 006-B4421-B( )
Automatic Flight Guidance 006-B1838-B( )
Color RTCA DO-178B Level A, B, C, D: RTCA DO-254 Level A:
and Control Systems TSO-C198 006-B4163-A( )
Fixed Wing 006-B4163-0( ) 006-C0164-0( )
(AFGCS) Equipment
011-02967-1( ) B Yaw Damper RTCA DO-178B Level E: RTCA DO-178B Level A,
006-B4163-T( ) B, C, D:006-B4163-B( )
RTCA DO-178B Level E:
006-B4163-U( )
RTCA DO-178B Level E:
C Flight Director 006-B4163-C( )

RTCA DO-178B Level A:

006-B1838-02 through
Autopilot for 006- B1838-1( )
A2
Rotorcraft RTCA DO-178B Level A, B, C, D: RTCA DO-178B Level
GMC 605H 006-B2071-0( ) A:|006-B2071-B( )
Monochrome 006-B1838-B( ) RTCA DO-254 Level A:
TSO-C198 RTCA DO-178B Level E:
Rotorcraft 006-C0164-0( )
006-B2071-T( ) RTCA DO-178B Level B:
011-02967-2( )
RTCA DO-178B Level B: 006-B2029-B( )
C Flight Director 006-B2029-0( )
RTCA DO-178B Level E:
006-B2029-5( )

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1.5.2 GMC 605 TSO Deviations
The GMC 605 has the following deviation.
Table 1-12 GMC 605 (011-02967-02, 011-02967-1( ), 011-02967-2( )) TSO Deviations

TSO Deviation
Garmin has been granted a deviation from TSO-C198 to use RTCA/DO-160F instead
TSO-C198 of RTCA/DO-160G as the standard for Environmental Conditions and Test Procedures
for Airborne Equipment.

1.6 Limitations
This article meets the minimum performance and quality control standards required by a technical standard
order (TSO). Installation of this article requires separate approval.
Low Temperatures: The Air Data Module was tested using -40ºC Ground Survival Low Temperature. If
the Module experiences temperatures below -40ºC for prolonged periods, warm the equipment to -30ºC
before flight.
GPS Antenna to AHRS Distance: The installer should locate the GPS antenna as short a distance from the
GMC 605 as practicable. Refer to Table 1-13 for guidance if using AHRS software v2.06 or earlier, later
software versions account for lever arm distance. During high rotation rate pedal turns, close spacing helps
the GPS receiver perceive similar accelerations as those sensed by the inertial accelerometers of the GMC
605 internal AHRS. This reduces the likelihood of inadvertent tripping of the internal AHRS comparison
monitor. For perspective, a standard rate 2-minute turn is performed at 3 degs/sec, well below the Yaw
Rates listed in Table 1-13.

Table 1-13 Lever Arm Distances

GPS Antenna to GMC 605 Lever Arm Minimum Sustained Yaw Rate That Can Reset AHRS

1m 50 degs/sec
2m 40 degs/sec
3m 30 degs/sec
8m 20 degs/sec
10m 15 degs/sec

Polar Region Operations: For installations in which the GMC 605 receives output from a GMU
magnetometer, operation in the following regions is not authorized due to unsuitability of the magnetic
fields near the Earth’s poles:
1. North of 72° North latitude at all longitudes
2. South of 70° South latitude at all longitudes
3. North of 65° North latitude between longitude 75° W and 120° W. (Northern Canada)
4. North of 70° North latitude between longitude 70° W and 128° W. (Northern Canada)
5. North of 70° North latitude between longitude 85° E and 114° E. (Northern Russia)
6. South of 55° South latitude between longitude 120° E and 165° E. (Region south of Australia and
New Zealand)
Specific equipment limitations are included in applicable sections in this document.

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1.7 Operating Instructions
This section contains generic operating instructions for TSO purposes only and is not to be used in place of
field operating instructions.

NOTE
Always refer to applicable airframe specific documentation for instructions on Garmin
AFCS operation. This documentation can be found on www.garmin.com.

1.7.1 GMC 605

The following is a list of controls found on the GMC 605 with associated function for a GMC 605
operating in normal mode:
• AP (Autopilot) key – The AP key engages/disengages the autopilot.
• FD (Flight Director) key – The FD key activates/deactivates the Flight Director.
• YD (Yaw Damper) key – The YD key engages/disengages the Yaw Damper.
• HDG (Heading) key – The HDG key selects/deselects the Heading mode.
• NAV (Navigation) key – The NAV key selects/deselects the Navigation mode.
• APR (Approach) key – The APR key selects/deselects the Approach mode.
• BC (Back Course) key – The BC key selects/deselects the BC mode.
• VNV (Vertical Navigation) key – The VNV key selects/deselects the vertical navigation mode.
• IAS (Indicated Air Speed) key – The IAS key selects/deselects the Indicated Air Speed mode.
• ALT (Altitude) key – The ALT key selects/deselects the Altitude Hold mode.
• FLC (Flight Level Change) key - The FLC key selects/deselects the FLC mode
• VS (Vertical Speed) key – The VS key selects/deselects the Vertical Speed mode.
• LVL (Level) key – The LVL key engages the autopilot in Level mode. Once Level mode is active,
subsequent presses of the LVL key have no effect.
• NOSE UP/DN Wheel – The NOSE UP/DN wheel controls the vertical speed reference (in VS
mode), pitch reference (in PIT mode), indicated airspeed reference (in IAS mode), and the altitude
reference (in ALT mode).
In addition to the controls on the GMC 605 itself, there are several controls that are located external to the
GMC that directly affect GMC operation:
• AP DISC key – The AP DISC key disengages the autopilot and can also be used to deactivate
Electronic Stability & Protection (ESP™ aviation technology).
• Pitch Trim Arm – The Pitch Trim Arm key arms the trim system and allows it to be manually
actuated using the Trim UP/DN rocker.
• Pitch Trim UP/DN Rocker – The Pitch Trim UP/DN Rocker runs the trim in the nose up or down
direction as long as the Trim Arm key is activated concurrently.
• GA (Go Around) key – The optional GA key activates the Go Around mode.
• CWS (Control Wheel Steering) key – The CWS key activates Control Wheel Steering as long as it
is held down.
• Dimming Control Knob – The optional Dimming Control knob changes the brightness level of the
GMC 605 display backlight and status LEDs.

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1.7.2 GMC 605H
The following is a list of the possible controls found on the GMC 605H with associated function for a
GMC 605H operating in normal mode:
• FCS (Flight Control System) key – The FCS key engages/disengages the flight control system.
• FD (Flight Director) key – The FD key activates/deactivates the display of the Flight Director bars.
• CPL (Couple) key – The CPL key couples/​decouples the flight control system from the flight
director.
• AP (Autopilot) key - The AP key engages ATT mode from the AP OFF state.
• SAS key – The SAS key engages the servos in the Stability Augmentation System (SAS) mode.
The servos continue SAS mode operation until they are disengaged directly by an external discrete
switch.
• HDG (Heading) key – The HDG key selects/deselects the Heading mode.
• NAV (Navigation) key – The NAV key selects/deselects the Navigation mode.
• APR (Approach) key – The APR key selects/deselects the Approach mode.
• DCL key – The DCL key selects/deselects the Deceleration Mode to reduce airspeed to a target
airspeed.
• IAS (Indicated Air Speed) key – The IAS key selects/deselects the Indicated Air Speed mode.
• HOV key – The HOV key engages the servos in Groundspeed Mode, and holds the present speed
over the ground.
• RHT key – The RHT key selects/deselects Radar Height Mode to hold the current radar altitude.
• ALT (Altitude) key – The ALT key selects/deselects the Altitude Hold Mode to move toward the
target altitude at a vertical speed selected by the pilot.
• ALTA key – The ALTA key selects/deselects the Altitude Acquire Mode to move toward the target
altitude at a predetermined vertical speed.
• VS (Vertical Speed) key – The VS key selects/deselects the Vertical Speed mode.
• LVL (Level) key – The LVL key engages the autopilot in Level mode. Once Level mode is active,
subsequent presses of the LVL key have no effect.
• NOSE UP/DN Wheel – The NOSE UP/DN wheel controls the vertical speed reference (in VS
mode), indicated airspeed reference (in IAS mode), and the altitude reference (in ALT mode).

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In addition to the controls on the GMC 605H itself, there are several controls that are located external to
the GMC that directly affect GMC operation:
• FCS DISC key – The FCS DISC key decouples or disengages the autopilot and can also be used to
deactivate the limit cue functions of the Electronic Stability & Protection (ESP).
• FTR (Force Trim Release) key – The FTR key resets the attitude trim point when decoupled or the
flight director references when coupled, and engages the autopilot if it was previously off.
• Beep Switch – The beep switch adjusts the attitude trim point when decoupled or the pitch flight
director references when coupled.
• External Level key (optional) – The external Level key engages the autopilot in Level mode.
• Dimming Control Knob – The optional Dimming Control knob changes the brightness level of the
GMC 605H display backlight, status LEDs, and keys (keys are controlled only when not
configured for photocell).
• External Yaw Damper key (optional) – For installations that include a yaw axis servo, the external
YD key engages/disengages the Yaw Damper.
• GA (Go Around) key – The optional GA key activates the Go Around mode.
• Yaw Beep (optional) - Yaw Beep adjusts the yaw axis control.
1.8 Reference Documents
The following publications are sources of additional information for installing the GMC 605. Before
installing the GMC 605, the installer should read all applicable referenced materials along with this
installation manual.
Table 1-14 Reference Documents

Part Number Document

190-00303-74 GTA 82 Trim Adapter Installation Manual
190-01277-00 GRA™ 5500 Radar Altimeter Installation Manual
190-01277-05 GRA 55 Installation Manual
190-01639-00 GSU 75 ADAHRS Installation Manual
190-01695-00 GFS 83 Installation Manual
190-01697-00 GLA 85 Installation Manual
190-01903-00 GSA 87 Installation Manual
190-01937-00 GFC 600 Automatic Flight Control System Part 23 AML STC Installation Manual
190-02081-00 GFC 600H Part 27 STC Installation Manual

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2 INSTALLATION OVERVIEW

2.1 Introduction
This section provides hardware equipment information for installing the GMC 605 and related hardware.
Installation of the GMC 605 should follow the aircraft TC or STC requirements. Cabling is fabricated by
the installing agency to fit each particular aircraft. The guidance of FAA advisory circulars AC 43.13-1B
and AC 43.13-2B, where applicable, may be found useful for making retro-fit installations that comply
with FAA regulations.

2.2 Installation Materials

The GMC 605 is available under the part numbers listed in Table 2-1.

Table 2-1 GMC 605 Catalog Part Numbers

Item Catalog P/N

GMC 605 Unit Only (011-02967-02) 010-01075-02
GMC 605 Color, Black, IAS, Unit Only (011-02967-12) 010-01075-12
GMC 605 Color, Gray, FLC, Unit Only (011-02967-14) 010-01075-14
GMC 605 Color, Black, FLC, Unit Only (011-02967-16) 010-01075-16
GMC 605H Unit Only w/FD, NV (011-02967-20) 010-01075-20
GMC 605H Unit Only w/o FD, NV (011-02967-22) 010-01075-22
GMC 605H Unit Only 4-Axis, SAS, NV (011-02967-24) 010-01075-24

2.3 Equipment Available

Each of the following accessories are provided separately from the GMC 605 LRU. A single connector
kit, installation rack, and mounting hardware (Section 2.8) is required to install the unit.

Table 2-2 Equipment Available

Equipment Garmin P/N

Configuration Module, Potted (w/kit), not required with Air Data Module 011-00979-03
GMC 605 Backplate Kit 011-03295-10
Sub Assy, Conn Kit, GMC 605 011-03296-00
Air Data Module (w/Kit) 011-04426-00
Position Sensor, String Pot, 2” 011-04817-00
String Pot, Connector Kit 011-05126-00
Installation Rack 115-01918-10

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 Table 2-3 Accessories Required But Not Provided

Item Garmin P/N Qty

013-00430-00
USB Jump Drive (formatted using FAT32) 1
or equivalent
Cable, USB, A Female to A Micro Male* 320-00726-01 1
*Garmin USB cable (320-00726-00 now discontinued) may also be used. Either cable can enable
communication with the Flash drive.

2.3.1 Contents of Available Kits

Table 2-4 Potted Configuration Module Kit Contents (011-00979-03)

Item Garmin P/N Qty

Potted Configuration Module w/EEPROM 011-02178-00 1
Harness, 4 Conductor 325-00122-00 1
Contact, Pin, Mil Crimp, Size 22D 336-00021-00 5

Table 2-5 GMC 605 Backplate Kit Contents (011-03295-10)

Item Garmin P/N Qty

Pre-bagged Screws “D” 011-02650-03 1
Connector Plate w/Inserts 115-01963-10 1
Flat Washer, SAE, SS, #4 212-00024-04 1
Alignment Pin, #4-40, Shoulder 233-00087-00 1

Table 2-6 GMC 605 Connector Kit Contents (011-03296-00)

Item Garmin P/N Qty

Backshell w/Hdw, 50/78 Pin 011-00950-04 2
Ground Adapter Shell, Size 4 & 5 011-01169-01 2
Screw, 4-40x.437, FLHP 100, SS/P, Nyl 211-63234-11 4
D-Sub, Hi Density D-Sub Connector, Mil Crimp, 78ckt 330-00185-78 2
Size 22D Pin Contact, Mil Crimp 336-00021-00 155
Size 22D Pin Contact, Crimp, 18 & 20 AWG 336-00044-00 4

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 Table 2-7 GMC 605 Air Data Module (w/Kit) Contents (011-04426-00)

Item Garmin P/N Qty

GMC Air Data Module Unit Only 011-04426-01 1
Screw, 4-40x.375, PHP, SS/P, w/NYL 211-60234-10 2
Wire Harness, 5 Conductor, Air Data Module 325-00496-00 1

Table 2-8 String Pot, Connector Kit Contents (011-05126-00)

Item Garmin P/N Qty

Cable Tie, 3.15” 231-10001-06 2
Conn, Plug, WTW, D369 Series, 6 Position, Pin Insert, Key N 330-01429-01 1
Conn, Rcpt, WTW, D369 Series, 6 Position, Socket Insert, Key N 330-01430-01 1
Strain Relief, D369 Series, 6 Position 330-90056-06 2
Cont, Pin, Mil Crimp, Size 22D 336-00021-00 6
Contact, Sckt, Mil Crimp, Size 22 336-00055-00 6

2.4 Installation Considerations and Data Prioritization

Fabrication of a wiring harness is required. Sound mechanical and electrical methods and practices are
required for installation of the GMC 605. Where multiple redundant interfaces types are available on
attached equipment (e.g., Navigators supplying both ARINC 429 and analog outputs), connections must be
planned in accordance with the GFC 600 Data Prioritization method, as shown in Table 2-9.

Table 2-9 Data Priority

Interface Type Data Priority

HSDB (Ethernet) 1 (highest)
ARINC 429 2
Analog 3 (lowest)

If multiple interfaces are wired, the GMC 605 software uses the highest priority interface. Lower priority
interfaces are ignored.

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2.5 Cabling & Wiring
Refer to the interconnect examples in Appendix B for wire gauge guidance.
Wiring must be installed in accordance with AC 43.13-1B Chapter 11, Sections 8 through 13. The
following issues must be addressed:
• Do not expose cabling and wiring to chafing
• Do not route cabling and wiring harnesses near flight cables
• Do not route cabling and wiring near high-energy sources. (e.g. DC motors, high heat sources)
• Wiring indicated as shielded in Appendix B must be shielded
• Pigtail lengths must be less than 3.0 inches

2.6 Electrical Bonding

Electrical equipment, supporting brackets, and racks should be electrically bonded to the aircraft’s main
structure. Refer to SAE ARP 1870 Section 5 when surface preparation is required to achieve electrical
bond. An equivalent OEM procedure may also be substituted. The electrical bond should achieve direct
current (DC) resistance less than or equal to 2.5 milliohms to local structure where the equipment is
mounted. Compliance should be verified by inspection using a calibrated milliohm meter.

2.7 Cooling Air

Cooling is not required for the GMC 605.

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2.8 Mounting Requirements
The GMC 605 is to be mounted using the GMC 605 Install Rack, see Figure 2-1.
The GMC 605 includes an extremely sensitive strap-down inertial measurement unit. It must be mounted
rigidly to the aircraft primary structure. Shock mounting should be avoided. The mounting must make
sure the installed unit is not exposed to vibration levels that exceed DO–160F levels claimed by the GMC
605. (See the GMC 605 Environmental Qualification Form, Section 1.4.1). Vibration outside of these
limits may result in degraded accuracy.
The GMC 605 mounting rack and back plate must be rigidly connected to the aircraft primary structure
through strong structural members capable of supporting substantial loads. Avoid areas that are prone to
severe vibration (e.g., areas close to engine mounts).
The GMC 605 should be mounted within 13 feet longitudinally and 6.5 feet laterally of the aircraft center
of gravity. The mounting location for the GMC 605 should be protected from rapid thermal transients, in
particular, large heat loads from nearby high-power equipment.
The GMC 605 mounting rack must be leveled to within -85° to +85° in aircraft longitudinal direction
(pitch), and 3° in aircraft lateral direction (roll). An aircraft leveling and offset setting procedure must be
carried out before flight. (This procedure is described in Section 3.10).
In regards to heading, the GMC 605 supports mounting in two azimuth orientations (i.e., connector
forward, or canted 7.5° of forward, to match the panel’s cant angle) and must be aligned within ±1.0° of
the applicable azimuth orientation to avoid heading errors. The mounting orientation will be stored in the
aircraft specific Configuration Module (either the backshell-mounted Configuration Module or the
memory chip within the Air Data Module).
Refer to Appendix A Outline and Installation Drawings for details.

Figure 2-1 GMC 605 Install Rack (115-01918-10)

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3 INSTALLATION PROCEDURE
3.1 Unpacking Unit
Carefully unpack the equipment and make a visual inspection of the unit for evidence of damage incurred
during shipment. If the unit is damaged, notify the carrier and file a claim. To justify a claim, save the
original shipping container and all packing materials. Do not return the unit to Garmin until the carrier has
authorized the claim.
Retain the original shipping containers for storage. If the original containers are not available, a separate
cardboard container should be prepared that is large enough to accommodate sufficient packing material to
prevent movement.
3.2 Wiring Harness Installation
Allow adequate space for installation of cables and connectors. The installer shall supply and fabricate all
of the cables. All electrical connections are made through two 78-pin D subminiature connectors.
Section 4 defines the electrical characteristics of all input and output signals. Required connectors and
associated hardware are supplied with the connector kit.
See Appendix B for examples of interconnect wiring diagrams. Construct the actual harnesses in
accordance with the aircraft manufacturer authorized interconnect standards.

Table 3-1 Pin Contact Part Numbers

78-Pin D-Subminiature Connector (P6051/P6052)

Manufacturer (Note 1)
18-20 AWG (Power Only) 22-28 AWG
Garmin P/N 336-00044-00 336-00021-00
Military P/N N/A M39029/58-360
1. Non-Garmin part numbers shown are not maintained by Garmin and consequently are subject to change without
notice.

Table 3-2 Recommended Crimp Tools

18-20 AWG 22-28 AWG

Hand Insertion/
Manufacturer Insertion/
Crimping Extraction
(Note 1) Positioner Positioner Extraction
Tools Tool
Tool
(Note 2)
Military P/N M22520/1-01 N/A M81969/1-04 M22520/2-09 M81969/1-04
Positronic 9507 9502-11 M81969/1-04 9502-3 M81969/1-04
AMP 601966-1 N/A 91067-1 601966-6 91067-1
Daniels AFM8 K774 M81969/1-04 K42 M81969/1-04
Astro 615717 N/A M81969/1-04 615725 M81969/1-04
1. Non-Garmin part numbers shown are not maintained by Garmin and consequently are subject to change without
notice.
2. Extracting the #18 and #20 contacts requires the expanded wire barrel be cut off from the contact. It may also be
necessary to push the pin out from the face of the connector when using an extractor due to the absence of the
wire. A new contact must be used when reassembling the connector.

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3.3 Backshell Assembly
The GMC 605 connector kit includes two Garmin backshell assemblies. Garmin’s backshell connectors
give the installer the ability to easily terminate shield grounds at the backshell housing using the Shield
Block grounding kit. To assemble the GMC 605 backshell, refer to instructions provided in the Shield
Block Installation Instructions, Garmin part number 190-00313-09.

3.4 Garmin Air Data Module (ADM) Installation

NOTE
The memory chip inside the Air Data Module stores configuration data.

The Garmin Air Data Module (011-04426-00) measures pitot and static pressures which are used by the
GMC605 to calculate indicated airspeed and pressure altitude. The ADM also includes a memory chip to
retain aircraft installation configuration settings if the GMC 605 is replaced with a different unit. The
ADM is fastened to the rear of the back plate, and pressure fittings connect it to the plumbing for the
aircraft pitot and static port.
The GMC 605 communicates with the ADM using a four-wire serial interface. A fifth wire supplies power
to the ADM. The ADM installation kit includes a wire harness (325-00496-00) for connection to one of
the GMC 605 D-sub connectors. The wire colors are listed in Table 3-3.

Table 3-3 Air Data Module Inputs and Outputs

Pin Name Color Connector Pin I/O

CONFIG MODULE CLOCK White P6052 23 OUT
CONFIG MODULE DATA Yellow P6052 42 IN
CONFIG MODULE GROUND Black P6052 24 GND
CONFIG MODULE POWER Red P6052 43 OUT
POWER OUT POSITIVE Blue P6052 21 OUT

The wire harness is routed out the back of the backshell and plugged into the ADM when the backplate
(rear connector plate) is assembled. Figure 3-1 shows the orientation of the ADM and fastener usage.
Wiring is described below:
1. Remove 0.17 inches of insulation from the end of each wire.
2. Crimp socket contacts onto each wire of the four-conductor wire harness.
3. Insert crimped socket contacts and wires into the applicable connector housing location.

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 Figure 3-1 Attachment of ADM to Rear Connector Plate

3.4.1 Pneumatic Connections

The installer is required to fabricate pneumatic hose connections and attach the aircraft pitot and static
pressure sources to the ADM.

NOTE
Check pneumatic connections for errors before operating the GMC 605 with ADM
attached. Incorrect plumbing could cause internal component damage. Use the following
cautions when connecting pneumatic lines.

1. Make sure the aircraft static system is plumbed to the port marked "S" on the ADM and the pitot
line is plumbed to the port marked "P".
2. Use appropriate air hoses and fittings to connect the pitot and static lines to the unit. Avoid sharp
bends and routing near aircraft control cables. The ADM should not be at the low point of the pitot
and static plumbing line, to avoid moisture or debris collecting at or near the unit.
3. Use care to avoid getting fluids or particles anywhere within the pitot and static lines connected to
the ADM.
4. Seal the threads of the ADM pneumatic fitting at the connector port. The thread size is 1/8-27
ANPT female thread. The mating fitting must have 1/8-27 ANPT male threads. Use caution to
make sure there are no pneumatic leaks.
Before completion of the installation, a pitot and static system leak check must be performed. Refer to the
aircraft maintenance manual for pitot and static system leak test instructions. Refer to Part 43, Appendix E
for approved practices while installing hoses and connections.

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3.5 Configuration Module Installation

NOTE
Installations with an optional Garmin Air Data Module do not require a configuration
module.

NOTE
The configuration module stores unit configuration data. This lets the installer remove
and replace the GMC 605 without loss of configuration data. Installation of the module is
part of the aircraft harness.

Do not install the configuration module in the connector backshell when the Garmin Air Data Module is
installed on the connector backplate. The Garmin Air Data Module has a built-in configuration data
storage device and interfaces to the GMC 605 through the same pins as the configuration module.
An Air Data Module is not required for installations that receive airspeed, altitude, and other parameters
from an external Air Data Computer (e.g, GDC 74A, GDC 72, GSU 75, or a GDU™ display providing Air
Data parameters). For these installations a Configuration Module must be attached to the GMC 605 in
place of the Air Data Module to provide memory storage for aircraft-specific installation settings. A four-
wire harness (325-00122-00) connects the serial communication signals listed in the first four rows of
Table 3-3. The Module itself is placed into a recess within the backshell of J6052. Refer to document
"G1000® Flight Deck Potted Configuration Module Installation into a Backshell" (190-00313-13) for
assembly instructions.

3.6 Collective Position Sensor Installation (Rotorcraft Only)

NOTE
The Garmin Collective Position Sensor is required for certain rotorcraft models only.

For rotorcraft not equipped with an OEM-installed potentiometer, the Garmin Collective Position Sensor
(011-04817-00) provides the GMC 605H with measurement of the collective lever position. The
measurement improves the performance of the GFC 600 HFCS in the following three ways.
1. By allowing for the flight control system to compensate for collective/yaw coupling effects.
2. By adjusting the rotorcraft pitch during precision pitch axis modes (such as approach mode
glideslope)
3. By inhibiting servo motion when the Collective Lever position indicates the rotorcraft is on the
ground

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3.6.1 Electrical Installation
The GMC 605H reads the Collective Position Sensor using a five-wire analog interface. Two output pins
supply 2500 Hz, 7 VRMS AC excitation signal to the sensor. One input pin reads the signal amplitude
applied to the sensor. One input pin reads the sensor’s output signal. A third input pin acts as a precision
reference. Either the ANALOG 1 or ANALOG 2 pin groupings may be used, as shown in Table 3-4 and
Table 3-5. The wiring connections are also shown in Figure B-13. When wired as shown, and with correct
mechanical installation, the voltage measured at the sensor output signal (when referenced to the sensor
reference signal) will increase in amplitude as the collective lever is raised.

Table 3-4 Collective Position Sensor Inputs and Outputs (ANALOG 1 option)

Signal Description Pin Name Connector Pin Wire Color

Excitation EXCITATION OUT HI P6052 69 Black
Excitation Reference EXCITATION OUT LO P6052 68 Red
Sensor Input ANALOG 1 IN Y P6052 77 Black
Sensor Output ANALOG 1 IN X P6052 78 White
Sensor Reference ANALOG 1 IN Z P6052 76 Red

Table 3-5 Collective Position Sensor Inputs and Outputs (ANALOG 2 option)

Signal Description Pin Name Connector Pin Wire Color

Excitation EXCITATION OUT HI P6052 69 Black
Excitation Reference EXCITATION OUT LO P6052 68 Red
Sensor Input ANALOG 2 IN Y P6052 74 Black
Sensor Output ANALOG 2 IN X P6052 75 White
Sensor Reference ANALOG 2 IN Z P6052 73 Red

NOTE
All signals used in the Collective Position Sensor interface must be isolated from aircraft
ground. This is needed for highest noise rejection, best EMC immunity, and to prevent
damage to the GMC circuitry.

NOTE
Verify the sensor’s output is never driven directly by the GMC EXCITATION signals. The
output is the wiper of a potentiometer, and is not designed to handle high currents.

NOTE
If the EXCITATION OUT pins are used with the Collective Position Sensor interface, they
are unavailable for connection to other equipment (DG, HSI, etc.).

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3.6.2 Mechanical Installation
The maximum extension length of the Garmin Collective Position Sensor is 2 inches. To attain acceptable
measurement resolution, the mechanical installation should be sized so the difference between maximum
extension (lever raised) and the retracted position (lever lowered) uses at least 50% of this length. The
retracted position should use at least 0.100 inches. This prevents the steel cable from ever becoming slack.
The fasteners used with the Position Sensor’s 2-56 threaded holes must be coated with thread-locker
(MIL-S-46163 Type II, Grade N Medium Strength, or equivalent such as Loctite 242, Garmin
291-00023-02), and torqued to 2.5 ± 0.5 inch-pounds.

CAUTION
During and before installation, do not allow the steel cable to snap back (i.e., freely
retract). Doing so will damage the sensor. Tension must be maintained on the cable at all
times.

NOTE
Do not pull the steel cable beyond its maximum extension length, 2 inches. Overextension
may damage the sensor. The installation location must provide adequate clearance from
nearby structures that might snag the sensor cable, or cause inaccurate readings due to
inadvertent pressure. The location must be free of debris and environmental exposures
that might affect the motion of the steel cable.

NOTE
Due to the small size of the sensor wire (30 AWG), an interposing connector is
recommended to transition to a larger wire size. Solder splicing is not recommended.
Refer to the STC Installation Manual for rotorcraft model-specific information.

3.6.3 Configuration
When the electrical and mechanical installation is complete, the Collective Position Sensor’s retracted and
extended positions must be configured. The collective lever position is shown as a percentage. See
Section 3.10.1.1 for the Configuration descriptions.

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3.7 Garmin Magnetometer Installation (Rotorcraft Only)
The GMC 605H receives measurements of the Earth’s magnetic field from the same GMU 44 that supplies
field measurements to the rotorcraft’s GSU 75 ADAHRS (or GRS 79 AHRS). The measurements enable
more comprehensive comparisons against internal inertial sensor measurements (gyro and accelerometer).
This improves performance in rotorcraft operation, especially for uncoordinated abrupt maneuvers that
occur regularly in rotorcraft operation.
The GSU 75 ADAHRS (or GRS 79 AHRS) supports most magnetometer needs: 1) supplying power;
2) supplying software updates when needed; 3) reporting detailed faults; 4) commanding the
magnetometer into calibration mode during installation; 5) assisting the installer during the Magnetometer
Interference Test.
The GMC 605H must gain magnetometer calibration information that is relevant to its own pitch and roll
offsets. This requires coordination with the rotorcraft’s GSU 75 ADAHRS (or GRS 79 AHRS) because
the commands are received from those products, not the GMC 605H itself.
The GMC 605H includes an internal memory that holds the magnetic field model. Garmin provides an
updated model on a 5-year basis. The model may be easily loaded into the GMC 605H using the front
panel USB port.

Table 3-6 Magnetometer Inputs

Pin Name Connector Pin I/O

RS-485 3A J6051 74 IN
RS-485 3B J6051 55 IN

NOTE
There are no direct connections with the Magnetometer for Magnetometer Power In,
Magnetometer Power Ground, or Magnetometer RS-232. Refer to the GSU 75
Installation Manual.

3.7.1 Magnetometer Installation

NOTE
The Magnetometer is installed with the GMC 605H in rotorcraft installations. It is not
used in the GMC 605 fixed wing installations.

NOTE
In each installation, the RS-422 output from a single Magnetometer is received by both the
GMC 605H internal AHRS and another external AHRS (GSU 75, GRS 79, or equivalent).
Magnetometer power, software loading, and RS-232 calibration commands are supplied
by the external AHRS.

Refer to Section 3.10 Post Installation Configuration & Checkout for calibration details. Refer to the
“POST INSTALLATION, CONFIGURATION, AND CHECKOUT PROCEDURE” within
190-01639-00, GSU 75 ADAHRS Installation Manual for detailed Magnetometer checkout including the
Magnetometer Interference Test.

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3.8 Equipment Rack Installation

CAUTION
Exercise caution when installing the rack in the instrument panel. Deformation of the
rack will make it difficult to install and remove the GMC 605.

NOTE
If the front lip of the mounting rack is behind the surface of the aircraft panel, the
GMC 605 connectors may not fully engage. For more information refer to Appendix A.

NOTE
Make sure no screw heads or other obstructions prevent the unit from fully engaging in the
rack. For drawing dimensions necessary to prepare the cutouts for the GMC 605 unit,
refer to Figure A-3. For drilling the mounting holes, the GMC 605 mounting rack may be
used as a template.

NOTE
The following step 3 can be done before or after the wire harness is installed in the
aircraft.

1. Install the rack in a rectangular hole (or gap between units) in the instrument panel, typically in the
radio stack. The lower front lip of the rack should be flush with, or extend slightly beyond, the
finished aircraft panel.
2. Use six #6-32 flat head screws and self-locking nuts to install the rack in the aircraft panel. The
screws are inserted from the inside through holes in the sides of the rack.
3. Use provided screws to attach the connector(s) to the backplate.
4. Align the backplate so the backplate screw heads pass through the keyed holes in the back of the
rack.
5. Slide the backplate downwards.
6. Attach the backplate by tightening the four #4-40 screws.
7. Use two #4-40 pan head screws to attach the Garmin Air Data Module to the backplate, if used.
Refer to Figure A-2.
8. Connect the wire harness to the Garmin Air Data Module, if used. Refer to Figure A-2.

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3.9 Unit Installation

CAUTION
The application of hex drive tool torque more than 8 in-lbs can damage the locking
mechanism.

NOTE
Before placing the unit in the rack, make sure the position of the retention mechanism is
correct. It may be necessary to insert the drive tool into the access hole and turn the hex
drive tool counterclockwise until if fully stops.
Insertion:
1. Slide the unit in until it stops.
2. Insert a 3/32” hex drive tool into the access hole on the unit face.
3. Turn the hex drive tool clockwise, and apply 8 in-lbs of torque maximum.
Removal:
1. Insert the hex drive tool into the access hole on the unit face.
2. Turn the hex drive tool counterclockwise until the hex drive tool stops.
3. Pull the unit from the rack.

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3.10 Post Installation Configuration & Checkout
The GMC 605 must be installed with the equipment listed in Table 3-7. For the equipment other than the
GMC 605 and the Air Data Module, refer to the appropriate installation manual for post installation
procedures.
Table 3-7 Required Equipment

Required Equipment Function Comments

GMC 605 AFCS Controller
Stores pitch and roll alignment
Memory chip inside ADM, or offsets and panel cant angle
Configuration Memory
inside Configuration Module needed by the GMC 605 internal
AHRS
2 to 4 servos may be required,
GSA 87 depending on STC
Servos
(or equivalent Garmin servos) recommendations for the aircraft
model
Airspeed source (Air Data
Module, GDC 74A, GDC 74B,
GDC 72, GSU 75, or GDC 7400)
AHRS aiding source
OR One airspeed source and as many
(airspeed, WAAS GPS, or
Garmin WAAS GPS (GTN™ 650/ as two GPS sources are supported
both)
750 avionics, GNS430W/
GNS530W, or GTX™ 3X5
transponder with GPS) or Both
GMC 605 itself
OR
Annunciator must be within pilot’s
GDU Display AFCS Annunciators
field of view
OR
GI 285 Remote Annunciator
Improve rotorcraft handling
For rotorcraft not equipped with an
Collective Position Sensor based on collective lever
OEM-installed potentiometer
usage
Improve operation during
GMU 44 or equivalent A magnetometer is required for
uncoordinated abrupt
Magnetometer (reception only) certain rotorcraft models.
rotorcraft maneuvers
2 to 4 servos may be required,
GFS 83 (or equivalent Garmin depending on STC
Rotorcraft Servos
rotorcraft servos) recommendations for the rotorcraft
model
3 linear servos may be required,
GLA 85 (or equivalent Garmin depending on STC
Rotorcraft Linear Servos
rotorcraft linear servos) recommendations for the rotorcraft
model
A trim adapter may be required,
GTA 82 (or equivalent) Trim Adapter depending on STC
recommendations for the aircraft.

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Rev. 12 Page 3-10
 Table 3-7 Required Equipment

Required Equipment Function Comments

Radar Height readings may be
GRA™ 55/5500 radar altimeter used, depending on STC
Radar Altimeter
(or equivalent) recommendations for the rotorcraft
model.
Engine operational status may be
used, depending on STC
GDU Display (or equivalent) Engine Instrument System
recommendations for the aircraft
model.

CAUTION
Before applying power to the system, make sure the control surfaces are free from
obstructions.

CAUTION
Check all aircraft control movements before flight is attempted to make sure the wiring
harness does not touch any moving part.

3.10.1 Functional Selector Switches and Display

NOTE
Due to differences in key labeling, access to installation operations differs by GMC 605
model.

Table 3-8 GMC 605 Installation Key Functions by Model

Fixed Wing 10 Key 12 Key
Action 8 Key Helicopter
(12 keys) Helicopter Helicopter
Boot into
FD or LVL LVL LVL NAV
Configuration Mode
Boot into USB Mode YD or ALT ALT VS APR
Reset Mode Flags HDG HDG HDG HDG
Continue HDG HDG NAV IAS

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3.10.1.1 Configuration Mode
To enter configuration mode:
1. See Table 3-8 to find the “Boot into Configuration Mode” button applicable to the unit.
2. When the configuration start-up screen (Figure 3-2) appears, press the CONTINUE
(Table 3-8) key.
3. Refer to Table 3-9 for navigating the settings in configuration mode

NOTE
The configuration mode start-up screen acts as a safeguard to prevent the pilot from
unintentionally accessing configuration mode. Upon entering configuration mode, if the
continue key (identified by the text, “CONT”) is not pressed within 60 seconds, the unit
will reboot into normal mode.
IN CONFIG MODE, SCROLL WHEEL
ON ENTERING CONFIG MODE, PRESS WITHIN (OR USE ALT AND VS KEYS) TO
60 SECONDS TO CONTINUE IN CONFIG MODE MOVE CURSOR UP AND DOWN

HOLD DOWN DURING IN CONFIG MODE, IN CONFIG MODE,

POWER ON FOR PRESS TO MOVE PRESS TO MOVE
CONFIGURATION MODE CURSOR BACKWARD CURSOR FORWARD
Figure 3-2 Configuration Mode Start-Up Screen (monochrome display unit)

Table 3-9 Configuration Mode Navigation

Fixed Wing 10 Key 12 Key
Action 8 Key Helicopter
(12 keys) Helicopter Helicopter
Cursor Forward or
VS VS VS DCL
Confirm Selection
Navigation Up or
Scroll Wheel Scroll Wheel Scroll Wheel NAV and APR
Down
Cursor Backward or
IAS IAS IAS HOV
Deselect

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Figure 3-3 lists all configuration pages. Not all pages are present in all system configurations.

PROD GMC DSP RMT DSP GFC

SYS I/O TEST
(Product (GMC Display (Remote Display (Status and
(System) (I/O Status) (System Tests)
Information) Settings) Settings) Operations)

STATUS MAIN BOARD BACKLGHT BACKLGHT AHRS RS-232 AUDIO

SERVO
INSTALL DISP BOARD LIGHTBUS LIGHTBUS ADC RS-485
(HELI ONLY)

ASSERTS AHRS PHOTOCEL PHOTOCEL ADM CAN KEYS

CONTRAST
DATALOGS SERVOS (MONOCHROME SERVOS ARINC 429
DISP. ONLY)

RANGE CAL
SW UPLOAD RMT ANNUNC DISCRETE
(HELI ONLY)

RIGGING
MANIFEST
(HELI ONLY)

COLL SNSR
(HELI ONLY)

GPS OFFSET
(HELI ONLY)

CALIBRATE

Figure 3-3 Configuration Pages Block Diagram

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3.10.1.1.1 SYS
Available selections are Status, Install, Asserts, Datalogs, and SW Upload.

Figure 3-4 Sys/Status Configuration Page (monochrome display unit)

Figure 3-5 Sys/Status Configuration Page (color display unit)

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Status page - Displays current status of the selections listed in Table 3-10. “Y” is for Yes, a positive
indication, “N” is for No, a negative indication.
Table 3-10 Sys/Status Selections
SELECTION DESCRIPTION
Analog Calibration Indicates whether the analog calibration has been successfully performed
FPGA Fail Indicates whether FPGA 1 has failed
HW Version Indicates the version of unit hardware
Sys Fail Indicates whether a hardware/system failure has been detected
High Temp Indicates an over temperature condition
Low Temp Indicates an under temperature condition
Status Valid Indicates whether the main board status is valid
Voltage Valid Indicates whether the main board voltage is valid (monochrome display unit)
Indicates the number of times the GMC605 unit has been powered on (color
Power Up Count
display unit)
Temp Indicates whether the main board temperature is valid
Aircraft Power A Indicates whether the Power Bus A voltage is valid
Aircraft Power B Indicates whether the Power Bus B voltage is valid
PALT Reports the pressure altitude (if ADM is present)
Indicates the operational mode of the main board processor (System, Test,
Main Mode
Boot Block, or Configuration)

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Install page - Displays current status of the selections listed in Table 3-11. These settings are stored in
the configuration module.
Table 3-11 Install Selections
SELECTION DESCRIPTION
PTRM Select Yes if the installation includes a pitch trim servo, otherwise select No.
Yaw Damper Select Yes if the installation includes a yaw damper servo, otherwise select No.
Select Yes if the installation includes a GI 285 remote mode annunciator panel,
GI 285
otherwise select No.
Select NO if the installation does not include an HSI or DG interface, otherwise
HSI/DG select the equipment that is interfaced to the GMC 605 for the purpose of being
used as an HSI/DG.
Select NO if the system is not interfaced to a flight director display, otherwise
Flt Dir select the equipment that is interfaced to the GMC 605 for the purpose of being
used as a Flight Director display.
Select YES if ARINC 429 or HSDB roll steering is provided directly to the GMC
GPS ROLSTR
605, otherwise select NO.
Select ANGULAR (ANGULR for color display units) for any TSO-C146 (WAAS)
GPS Dev
GPS. Select LINEAR for any non-WAAS GPS.
Select YES if the installation includes Garmin displays and software versions that
VNAV
support vertical navigation.
Select the collective position sensor hardware depending on the installation:
COL SNSR
NONE, LVDT, or POT.
Select the sensor used for cabin pressure depending on the installation: NONE,
CBN PRSSR
ADM.
Select TXI if the installation is connected to a Garmin Txi™ display, otherwise
EIS
select NONE.
RAD ALT Select YES if the installation includes a radar altimeter, otherwise select No.
YTRM Select YES if the installation includes a Yaw Trim servo, otherwise select No.
RTRM Select YES if the installation includes a Roll Trim servo, otherwise select No.
Select NO, if the installation does not include a Vertical Deviation Indicator
VDI
(Garmin Txi or third party), but does include a Garmin GTN.
IAS Units (SPD
Select KT if airspeed mode will use knots. Select MPH if airspeed mode will use
UNITS for color
miles per hour. Select KPH if airspeed mode will use kilometers per hour.
display units)
ALT Units (color Select FT if altitude will be displayed in feet and M if altitude will be displayed in
display units) meters.

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Asserts page - Download Asserts using the Garmin USB cable connected through the port on the bezel of
the GMC 605. See Section 3.13 for details.
Datalogs page - Download Datalogs using the Garmin USB cable connected through the port on the bezel
of the GMC 605. See Section 3.12 for details.
SW Upload page - The Garmin USB cable must be connected to the port on the bezel of the GMC 605.
The data is provided by a USB drive loaded with current software. Press Upload to begin software update.
See Section 3.11 for details.

NOTE
Use only the Garmin USB cable.

NOTE
The GMC displays the text "ERROR - USB STICK INCOMPATIBLE" if an incompatible
cable or jump drive is detected.

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3.10.1.1.2 PROD
Displays the part number, version, and serial number (if applicable) for all product data in the GFC 600
system. A field will display dashes “-” if the product is not communicating or data is not available.

Figure 3-6 Prod/Main Board Configuration Page (monochrome display units)

Figure 3-7 Prod/Main Board Configuration Page (color display units)

Main Board page - Displays part number, version, and serial number of the System, Boot Block, Region
List, FPGA, Gain, Test, Audio Database, Audio Config, ARINC Config, Aircraft Config, Install Config,
and Key files stored on the Main Board and of the Installation Config files stored on the Configuration
Module or Air Data Module.
Display Board page - Displays part number, version, and serial number of the System, Boot Block, USB,
Config, MLO, Test, Region List, and Key files stored on the Display Board.
AHRS page - Displays part number, version, and serial number of the System, Boot Block, Region List,
IGRF, and Configuration files stored on the AHRS Board.
Servos page - Displays part number, version, and serial number of the Pitch Mon, Pitch Ctl, Roll Mon,
Roll Ctl, Yaw Mon, Yaw Ctl, Pitch Trim Mon, Pitch Trim Ctl, Roll Trim Mon, Roll Trim Ctl, Yaw Trim,
Mon, Yaw Trim Ctl, Collective Trim Mon, Collective Trim Ctl, Pitch Linear Mon, Pitch Linear Ctl, Roll
Linear Mon, Roll Linear Ctl, Yaw Linear Mon, and Yaw Linear Ctl, depending on system configuration.
For each of these items, System, Gains, Boot Block, Region List, and Key can be displayed.
Remote Annunciator page - Displays part number, version, and serial number of the Remote Annunciator
GI 285.

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Manifest page - The manifest system compares reported product data from each LRU against a list of
expected product data. The versions in the expected list, are the versions from the released loader card
image. The status of the selections is listed in Table 3-12. The manifest data is stored on the display
board. A Pass indication results if both the expected and reported versions match. If the reported version
has a dashed line, the LRU is not reporting product data, this results in a Fail indication. A Fail indication
also results if the LRU reports an unexpected (incorrect) version.
Table 3-12 Manifest Page Selections
COLUMN DESCRIPTION
LRU Indicates which LRU is reporting the region
REGION Indicates which region is being tested
R/RSLT (Result) Displays the result of the comparison. P = Pass F = Fail
EXP (Expected) Displays the expected region version from the manifest.
REP (Reported) Displays the reported region version from the LRU.

Figure 3-8 Manifest Page, Pass Indication (monochrome display units)

Figure 3-9 Manifest Page, Fail Indication (monochrome display units)

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 Figure 3-10 Manifest Page, Pass Indication (color display units)

Figure 3-11 Manifest Page, Fail Indication (color display units)

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3.10.1.1.3 GMC DSP
Available selections are Backlight, Light Bus, Photocell, and Contrast (Monochrome units only). These
settings are stored in the GMC 605 configuration module.

NOTE
Once configuration is complete, be sure to review the performance of the backlighting
through the full range of inputs (0% to 100%) when driven by both the photocell and
lighting bus.
Figure 3-12 and Figure 3-13 show the Piecewise Graph Backlight Curve System.

Figure 3-12 Piecewise Graph GMC DSP/Backlight Configuration Page (monochrome

display units)

Figure 3-13 Piecewise Graph GMC DSP/Backlight Configuration Page (color display units)

Backlight page - Displays and allows the setting of the backlight source and transition. This page also
shows the current lighting curve status information in the bottom right box
SOURCE
Table 3-13 describes the backlight source selections:
Table 3-13 Backlight Source Selections
SELECTION DESCRIPTION
DEFAULT. Backlight level is determined by the ambient light level as
PHOTOCELL
measured by the GMC 605 photocell.
14 VDC Backlight level tracks a 14 Volt DC aircraft lighting bus.
28 VDC Backlight level tracks a 28 Volt DC aircraft lighting bus.
5 VDC Backlight level tracks a 5 Volt DC aircraft lighting bus.
5 VAC Backlight level tracks a 5 Volt AC aircraft lighting bus.

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 TRANSITION
Sets the minimum lighting bus threshold for when the display switches from the lighting bus
source to photocell. This setting is not applicable when the source is set to photocell. The value
range is 0 to 100 and the default setting is 25. Example: Source is set to 5 VDC and transition is
set to 20%. When the lighting bus input reaches 1VDC (20% of 5 VDC) the display will
automatically switch the source from lighting bus to photocell. This feature ensures the display
can still be visible even if the lighting bus is set to a low value.
SRC
Displays the backlight source inside of the box in the bottom right corner of the screen for
reference. This box is shown on every GMC DSP page except for the contrast page. This field
makes it easier to remember what source is selected when adjusting points on other pages.
I
Displays the input lighting level as a percentage in the box in the bottom right corner of the screen
for reference. This shows the input lighting level of either the photocell or the lighting bus
depending on the source (SRC) listed above.
O
Displays the output lighting level as a percentage in the box in the bottom right corner of the
screen for reference. This shows the output lighting level of either the display or the keypad
depending on which device the points are being adjusted for (the default for the backlight page is
the display).
Figure 3-14 and Figure 3-15 show the GMC DSP/Photocell Configuration Page.

Figure 3-14 GMC DSP/Photocell Configuration Page (monochrome display units)

Figure 3-15 GMC DSP/Photocell Configuration Page (color display units)

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Light Bus page - Displays and allows the setting of the points in the lighting bus piecewise curve for both
the display and the keypad backlights. The third menu option along the top (DISP/KEYS) is used to select
between the display and the keypad backlights.
The backlight values are set using a four-point piecewise curve. The first input (X1) and fourth input (X4)
are set to 0 and 100 respectably and cannot be changed. This ensures that for any input value, there is a
defined output value. The other two input values (X2 and X3) can be adjusted. Each input must be greater
than the previous input (X4 > X3 > X2 > X1) and each output must be greater than or equal to the previous
output (Y4 >= Y3 >= Y2 >= Y1).
POINTS
The left side of the screen shows two points depending on the selected page in the top right. These
fields are used to set the input and output points (all are as a percentage).
STATUS BOX
The center of the screen shows the status box with the source and the input/output percentages.
This data is explained above in the backlight page section.
GRAPH
The right side of the screen provides a visual representation of the lighting curve in the form of a
graph. The graph will automatically update when a value is changed. The X axis represents the
input and the Y axis represents the output. Like the output percentage in the status box, the graph
represents the display or the keypad backlight depending on which is currently being adjusted.
Photocell page - Displays and allows the setting of the points in the photocell piecewise curve for both the
display and the keypad backlights. The third menu option along the top (DISP/KEYS) is used to select
between the display and the keypad backlights. The Photocell page uses the same presentation and rules as
the Light Bus page (see preceding Light Bus page description).
Contrast page (monochrome units only) - Displays and allows the setting of the display contrast offset
setting.
This is a direct adjustment of the display contrast. Default factory contrast is shown as zero (0).
Display contrast is set manually in the factory to achieve optimum contrast performance in cold, hot, and
ambient temperatures. The factory set value is not intended to be used as a production requirement. The
contrast level can be manually set during installation if further adjustments are necessary.

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3.10.1.1.4 RMT DSP
Used to modify the Brightness, Light Bus, and Photocell settings for the GI-285 (if installed). These
settings are stored in the GMC 605 configuration module.

NOTE
If configuring the GI 285 settings, make sure the GI 285 has been enabled under the SYS >
INSTALL page (Section 3.10.1.1.1). If the GI 285 has not been enabled these pages will
display GI 285 NOT CONFIGURED.

Figure 3-16 and Figure 3-17 show the Piecewise Graph Backlight Curve System.

Figure 3-16 Piecewise Graph Remote DSP/Backlight Configuration Page (monochrome

display units)

Figure 3-17 Piecewise Graph Remote DSP/Backlight Configuration Page (color display
units)

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Backlight page - Displays and allows the setting of the backlight source and transition.

SOURCE
Table 3-14 describes the backlight source selections:

Table 3-14 Backlight Source Selections

SELECTION DESCRIPTION
DEFAULT. Backlight level is determined by the ambient light level as
PHOTOCELL
measured by the GI-285’s photocell.
14 VDC Backlight level tracks a 14 Volt DC aircraft lighting bus.
28 VDC Backlight level tracks a 28 Volt DC aircraft lighting bus.
5 VDC Backlight level tracks a 5 Volt DC aircraft lighting bus.
5 VAC Backlight level tracks a 5 Volt AC aircraft lighting bus.

TRANSITION
Sets the minimum lighting bus threshold for when the display switches from the lighting bus
source to photocell. This setting is not applicable when the source is set to photocell. The value
range is 0 to 100 and the default setting is 25. Example: Source is set to 5 VDC and transition is
set to 20%. When the lighting bus input reaches 1VDC (20% of 5 VDC) the display will
automatically switch the source from lighting bus to photocell. This feature ensures the remote
annunciator can still be visible even if the lighting bus is set to a low value.

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Light Bus page - Displays and allows the setting of the points in the lighting bus piecewise curve for the
remote annunciator backlights.
The backlight values are set using a four-point piecewise curve. The first input (X1) and fourth input (X4)
are set to 0 and 100 respectably and cannot be changed. This ensures that for any input value, there is a
defined output value. The other two input values (X2 and X3) can be adjusted. Each input must be greater
than the previous input (X4 > X3 > X2 > X1) and each output must be greater than or equal to the previous
output (Y4 >= Y3 >= Y2 >= Y1).
POINTS
The left side of the screen shows two points depending on the selected page in the top right. These
fields are used to set the input and output points (all are as a percentage).
STATUS BOX
The center of the screen shows the status box with the currently selected backlight source. This
field is to make it easier to remember what source is selected when adjusting points on other
pages.
GRAPH
The right side of the screen provides a visual representation of the lighting curve in the form of a
graph. The graph will automatically update when a value is changed. The X axis represents the
input and the Y axis represents the output.
Photocell page - Displays and allows the setting of the points in the photocell piecewise curve for the
remote annunciator backlights. The Photocell page uses the same presentation and rules as the Light Bus
page (see preceding Light Bus page description).

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3.10.1.1.5 GFC
Available selections are: AHRS, ADC, ADM, SERVOS, RANGE CAL (GMC 605H units only),
RIGGING (GMC 605H units only), COLL SENSOR (GMC 605H units only), GPS OFFSET (GMC 605H
units only), and CALIBRATE.

Figure 3-18 GFC/AHRS Configuration Page (monochrome display units)

Figure 3-19 GFC/AHRS Configuration Page (color display units)

AHRS Page (ver. 1) - Displays Internal and External Pitch, Roll, Magnetic Heading (with a magnetometer
only), X Acc, Y Acc, Z Acc, Pitch Body Rate, Roll Body Rate, Yaw Body Rate, and Inertial Altitude Rate
values. Also, displays AHRS handshake status, AHRS PFT status, and the status of the three AHRS
debugging discretes. These sub-pages may be helpful when the PFT indication persists for too long. The
“√” check mark means “valid”, X means “invalid”:
GFC AHRS HANDSHAKE: Verifies internal AHRS configuration and calibrations
◦ FINAL: PASS (entire status of the internal AHRS handshake checks)
◦ CNFG: GOOD (internal AHRS configuration is valid)
◦ P/R: GOOD (internal AHRS pitch/roll offset calibration was successful)
◦ MAG: GOOD (rotorcraft only: internal AHRS has good magnetometer installation
calibration)
◦ MIT: (magnetometer interference test result, always N/A)
GFC AHRS PFT: Verifies current pitch and roll attitudes, and AHRS aiding is adequate
◦ PITCH: √ (internal AHRS pitch attitude is valid)
◦ ROLL: √ (Internal AHRS roll attitude is valid)
GFC AHRS DISC 270, 271, 272: Detailed discrete status bits (contact Garmin support for details)

AHRS Page (ver. 2) - Displays AHRS 1, AHRS 2, and Standby AHRS, Pitch, Roll, Magnetic Heading, X
Acc, Y Acc, Z Acc, Pitch Body Rate, Roll Body Rate, Yaw Body Rate, and Inertial Altitude Rate values.
ADC Page (ver. 1) - Displays SAT, IAS, TAS, VS, DALT, PALT, STAT P, and DIFF P values for
ADC 1.
ADC Page (ver. 2) - Displays TAT, IAS, TAS, VS, DALT, PALT, STAT P, and DIFF P values for
ADC 1, ADC 2, and Standby ADC.

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ADM Page - Displays SAT, IAS, TAS, VS, PALT, STAT P, and DIFF P values. When Cabin Pressure
(CBN PRSSR) is configured as ADM, the page will show the cabin pressure altitude instead of the other
data.
Servos Page - Displays servo diagnostic information for each connected servo. This contains discrete
input data or status of servo systems. The items are: program 1-4, AP disconnect, pre-flight test status,
FTR, discrete inputs 1-4, voltage, current, position, speed, torque, and position. Also contains the servo
slip clutch test (see Section 3.10.2.8).
Range Cal Page (Heli Only) - Calibrate movement range of rotorcraft servos (see Section 3.10.2.3).
Rigging Page (Heli Only) - Provides selectable options for systems with Garmin GLA 85 linear actuators
which allow the installer to change the displacement of the actuator for the purpose of rigging the aircraft
flight controls. For selectable axes, PITCH, ROLL, and YAW, the page displays a status, trim actuator
position, linear actuator position, selectable command, and start command. This manual does not specify
any rigging procedures and installers should consult the Aircraft Manufacturer’s data for specific
instructions on how to rig the primary flight controls.

Figure 3-20 GFC/RIGGING Configuration Page

STATUS: See Table 3-15.

Table 3-15 Status

Status Meaning
PFT IN PROGRESS Actuators are performing PFT.
VERIFYING ON GROUND Actuators have passed PFT but are not yet ready for rigging command.
READY FOR LINEAR CMD Actuators have passed PFT and are ready for rigging command.
START command has been selected, but actuators are still performing
WAITING FOR PFT
PFT.
RIGGING IN START command has been selected, and actuators are ready for rigging
PROGRESS… command.
RIGGING COMPLETE Rigging command has completed successfully.
RIGGING FAILED Rigging command has failed.
COMMAND TIMED OUT Rigging command was sent to actuators, but no response was received.
PFT TIMEOUT Actuators have not passed PFT within the allowable time.

TRIM ACTUATOR POSITION: The GFS 83 trim actuator position is displayed as a percentage
and in degrees.
LINEAR ACTUATOR POSITION: The linear actuator position is displayed as a percentage and
in millimeters.

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 SELECTABLE COMMAND:

Table 3-16 Selectable Command

Command Meaning
CENTER Center the linear actuator within its allowed range of motion.
MAX Move the linear actuator to its maximum allowed displacement.
MIN Move the linear actuator to its minimum allowed displacement.
RECAL Mechanically recenter the linear actuator.

START COMMAND: Select “START” to start the selected command.

Coll Snsr Page (Heli only) - Calibrate movement range of Collective Lever position sensor (see
Section 3.10.2.4).
GPS Offset Page (Heli only) - Enter the Lever Arm Distance (the distance from the GPS antenna to the
GMC AHRS). Pick the antenna location for each of the configured GPS offsets for the following list:
HSDB, RS232 4, and RS232 5. The options for each location are either configured as none or “Antenna
X”. The STC data included with this airframe will inform which antennas are connected with which GPS
source if any are configured. See Table 1-13 for details.
Calibrate Page - See Section 3.10.2.1 for pitch/roll AHRS offset calibration, magnetometer calibration,
and engine run-up check.

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3.10.1.1.6 I/O
Available selections are RS-232, RS-485, CAN, ARINC 429, and Discrete

Figure 3-21 I/O/RS-232 Configuration Page (monochrome display units)

Figure 3-22 I/O/RS-232 Configuration Page (color display units)

Possible indications in the Status column (applicable to RS-232, RS-485, CAN, and ARINC 429) follow:
• Checkmark: Port Status OK (normal operation)
• 'X': Port Status Fail
• 'NA': Port Status Not Applicable
• '?': Port Status Unknown
• '--' (two dashes): Information not available
The Format column indicates which external interface each channel is connected to. The supported
interfaces for each of the available I/O selections are as follows:
RS-232 - Displays Status and Format settings for the 6 RS-232 channels
Supported options for the RS-232 Format column follow:

OFF GRS 77 #1 GDC 74 #1 GDC 74 #2

GRS 77 #2 GSU 75 #1 GSU 75 #2 Internal AHRS
GI 285 MAPMX #1 MAPMX #2

RS-485 - Displays Status and Format settings for the 2 RS-485 channels for configurable RS-485 channels
1 and 3. Channel 2 is reserved for Servo usage. Supported options for the RS-485 Format column follow:
• OFF
• GFC 600 (Servos)
• GMU

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CAN - Displays Status and Format settings for the 2 CAN channels. Supported options for the CAN
Format column follow:
• OFF
• GFC 600 (Servos)
ARINC 429 - Displays Status, Speed (H=High, L=Low), and Format settings for the 7 input and 2 output
ARINC 429 channels
Supported options for the ARINC 429 Format column follow:
• OFF
• ADC
• AHRS
• ADAHRS
• RADAR HT
• CNFG 1
• CNFG 2
• CNFG 3
Discrete - Displays Discrete Number, Active Logical Level, and Function settings for the 26 Discrete
Inputs and 4 Discrete Outputs. Discretes will be named or will have a number.
DIS: Discrete Number
LVL: Active Logical Level of the pin. H = active high, L = active low
ACTV: State of the discrete. Y = active, N = not active
FUNCTION: Name or number of the associated aircraft system signal

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3.10.1.1.7 TEST
Available selections are Audio, Servo (Heli only), and Keys

Figure 3-23 Test/Audio Configuration Page (monochrome display units)

Figure 3-24 Test/Audio Configuration Page (color display units)

Audio Page - Press PLAY to start (and press STOP to discontinue) the AP Disconnect Tone. Adjust the
volume to an appropriate level for the aircraft. Make sure the audio is loud enough for the pilot to hear.
Servo Page (Heli only) - Provides verification of servo installation wiring, See Section 3.10.2.6.
Keys Page - Starts test for all keys. Press each key (and move the scroll wheel up and down) and verify
the LCD displays an output that corresponds to the key label. If no keys are pressed for 3 seconds, the
GMC 605 will automatically exit the key test page.

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3.10.2 Post Installation Calibration Procedures

NOTE
The GMC 605H shares the magnetometer that is powered and commanded by the GSU/
GRS. For optimum sensing accuracy, and to save installation time, it is recommended that
both magnetometer calibrations be performed simultaneously. Refer to the Dual
Magnetometer Calibration instructions in the applicable rotorcraft STC Installation
Manual for Post Installation Configuration & Checkout procedures.
After mechanical and electrical installation of the GMC 605 has been completed, before operation, a set of
post-installation calibration procedures must be carried out. Table 3-17 describes the necessary calibration
procedures. Perform the procedures in the suggested completion order to optimize installation efficiency
(and for GMC 605H, for magnetometer accuracy).
Table 3-17 Post-Installation Calibration Procedure Summary

Installations Suggested
Calibration Procedure
Procedure Name Requiring Completion
Procedure Description
Procedure Order
Pitch/Roll Offset
A Level Aircraft All installations Second
Compensation
Fixed Wing Engine Validate vibration
All fixed wing
B Run-Up Vibration characteristics of First
installations
Test installation
Rotorcraft Servo Calibrate servo All rotorcraft
C Any Order
Range Calibration movement range installations
Rotorcraft
Collective Lever Calibrate lowered and installations with
D Any Order
Position Calibration raised lever positions collective position
sensor
With aircraft leveled,
calibrate
Magnetometer All rotorcraft
E magnetometer pitch/ Fifth
Calibration installations
roll offset. Calibrate
magnetic readings.
Allows checking of
Servo Post Beeps, FTR, and AP All rotorcraft
F Third
Installation Checkout Disconnect in each installations
axis
Magnetometer
Use GSU/GRS AHRS
Interference Test
to identify and correct All rotorcraft
G (see GSU 75 Fourth
magnetic interference installations
ADAHRS Installation
sources.
Manual)
Fixed wing
Automated Slip Verify slip clutch installations with
H Sixth
Clutch Test operation GSA80, GSA81, or
GSA80HS servos

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 NOTE
If removal and replacement of a GMC 605 is required after post-installation calibration
has been completed, the unit mounting rack must not be moved. If the mounting hardware
that secures the GMC 605 mounting rack is loosened for any reason, a new post-
installation calibration procedure A and B must be carried out before the aircraft can be
returned to service.
3.10.2.1 Calibration Procedure A: Pitch/Roll Offset Compensation by Aircraft Leveling
1. Level the aircraft to within ±0.25° of zero pitch and zero roll.
2. Enter configuration mode and navigate to the GFC>Calibrate>P/R page.
3. Highlight the 1/9 selection then move the highlighting to select 2/9, 3/9, 4/9, 5/9, 6/9, 7/9, 8/9
while verifying the on-screen instructions on each page.
4. Move the highlighting to select 9/9.
5. Press the CONFIRM key to select “Begin Calibration”.
6. Move the highlighting to select “Begin Calibration”, then press the CONFIRM key (to begin the
calibration).

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3.10.2.2 Calibration Procedure B: Fixed Wing Engine Run-Up Vibration Test

NOTE
Calibration Procedure B is required for all fixed wing installations to validate the
vibration characteristics of the installation. Calibration Procedure A is not required
before this procedure.

NOTE
Calibration Procedure B is not applicable to rotorcraft.

1. Enter configuration mode and navigate to the GFC>Calibrate>Engine page.

2. Highlight the 1/8 selection then move the Scroll Wheel downward to select 2/8.
3. Follow the on-screen instructions to make sure the aircraft is in a location where the engine can
safely be increased to full throttle.
4. Move the Scroll Wheel downward to select 3/8, 4/8, 5/8, 6/8, 7/8 while verifying the on-screen
instructions on each page.
5. Move the Scroll Wheel downward to select 8/8.
6. Press the CONFIRM key to select “Begin Run-up Test” (monochrome display units) or “Start
Calibration” (color display units).
7. Move the Scroll Wheel downward to highlight “Begin Run-up Test”, then press the CONFIRM
key to begin the run-up test.
8. Throttle engine according to on-screen instructions on screens 3/8 through 7/8 in step 4.
9. Move the Scroll Wheel downward to highlight “Complete” (if passed) or “Quit” (if failed) then
press the CONFIRM key to finish the run-up test.
10. Pass/fail is displayed to indicate the result of the vibration test. If the test fails, the specific
measurements causing the failure are identified and numeric values are displayed. Use the Scroll
Wheel to scroll through and view the entire list of failed measurements. If failures are indicated,
the engine run-up test may be repeated up to three times. If the test does not pass after three
attempts, then the installation should be considered unreliable until the source of the vibration
problem is identified and remedied.

NOTE
If the engine run-up test fails repeatedly, record the values that are reported to be out of
range for future reference.

The following are potential causes for failure of the engine run-up test:
a) Excessive flexibility of the GMC 605 mechanical mounting with respect to airframe (See
Section 3.9).
b) Vibrational motion of the GMC 605 caused by neighboring equipment and/or supports.
c) Mounting of the GMC 605 at a location that is subject to severe vibrations (example: close
to an engine mount.)
d) Mounting screws and other hardware for the GMC 605 not firmly attached.
e) Absence of mounting supports recommended by the aircraft manufacturer.

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 f) GMC 605 connector not firmly attached to unit.
g) Cabling leading to the GMC 605 not firmly secured to supporting structure.
h) An engine/propeller combination that is significantly out of balance.

NOTE
In some aircraft, attempting the engine run-up test on a day with very strong and/or gusty
winds may cause the test to occasionally fail. However, windy conditions should not be
taken as evidence the test would pass in calm conditions; an actual pass is required before
the installation can be considered adequate.

3.10.2.3 Calibration Procedure C: Rotorcraft Servo Range Calibration (GMC 605H units
only)
Range (PITCH, ROLL, YAW, COLLECTIVE) Calibration:
1. Enter configuration mode and navigate to the GFC>Range Cal page.
2. Using the highlighting, select Save Strap and press the CONFIRM key to save off the input.
3. Make sure the pre-flight tests have successfully completed by waiting for the “PFT” CAS message
to extinguish before continuing to the next step.
4. Wait 10 seconds before continuing to the next step.
5. Select START and follow the on screen instructions.
6. Move the servo through the full control range and select STOP.
7. Verify the range calibration was successful.
3.10.2.4 Calibration Procedure D: Collective Lever Position Calibration (GMC 605H units
only)
Collective Lever Position Calibration:
1. Enter configuration mode and navigate to the GFC>Coll SNSR page.
2. Press the CONFIRM key to move the cursor to START under Begin Calibration (an arrow will be
visible next to START).
3. Move the highlighting up or down to select START.
4. Press the CONFIRM key to begin the calibration.
5. Move the Collective Lever to full down and full up positions per the calibration instructions on the
GMC 605 display.
6. Use the CONFIRM key and highlighting to save the calibration.
7. After the GMC 605 has reported a successful calibration, confirm the calibration setting by
displacing the Collective Lever to full up and full down positions.

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3.10.2.5 Calibration Procedure E: Magnetometer Calibration (GMC 605H units only)

NOTE
Two magnetometer calibration procedures defined in the GSU 75 ADAHRS Installation
Manual must be completed successfully before performing the GMC 605H Magnetometer
Calibration Procedure: (1) Procedure B, "Magnetometer Calibration" and
(2) Procedure E, "Magnetometer Interference Test".

NOTE
GMC 605H Calibration Procedure A must be successfully completed before Calibration
Procedure E. If GMC 605H Calibration Procedure A is repeated, then GMC 605H
Procedure E must also be repeated.

NOTE
GMC 605H Calibration Procedure E must be carried out at a location that is determined
to be free of magnetic disturbances, such as a compass rose. Attempting to carry out this
maneuver on a typical ramp area will not yield a successful calibration. The accuracy of
the AHRS cannot be guaranteed if this calibration is not performed at a magnetically
clean location. A method for evaluating the magnetic disturbances at a candidate site is
described in the section, "Site Evaluation of Magnetic Disturbances for Magnetometer
Calibration Procedure" in the GSU 75 ADAHRS Installation Manual, Garmin part
number 190-01639-00.

Taxi the aircraft to a site that has been determined to be free of magnetic disturbances. Make sure there are
no nearby magnetic materials on or near the perimeter of the site. If unavoidable, maneuver the aircraft to
keep the magnetometer from passing within twenty feet (6.1 meters) of such objects. Additionally make
sure that vehicles or other aircraft are an adequate distance [forty feet (12.2 meters)] away from the aircraft
under test.
At the site, align the aircraft to a heading of magnetic north (5°). The aircraft should be positioned to
enable clockwise turning around the compass rose. For helicopters, it is best to position the aircraft in the
center of the compass rose. These positions are depicted in Figure 3-25.

Figure 3-25 Helicopter Position Examples

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With the aircraft stationary, initiate the GMC 605 magnetometer calibration procedure as follows:
1. Enter configuration mode and navigate to the GFC>Calibrate>Mag page.
2. Navigate to the Mag page in config mode (GFC > Calibrate>Mag).
3. Make sure that each of the pre-calibration steps has been completed. The pre-calibration
instructions will explain what will happen during the calibration.
4. When START TEST is visible, press the CONFIRM key. A selection pointer will appear to the
right of START TEST.
5. Use the highlighting to select START TEST again.
6. Press the CONFIRM key to begin the calibration. The GMC 605 display will advise the operator
when to turn the aircraft, when to stop, and when to turn again.

NOTE
For system software versions before v2.40, an extra step must be taken after step 6, but
before step 7, to calibrate the magnetometer. The first attempt to calibrate the aircraft per
power cycle will not send the magnetometer start procedure and the software will stall
indefinitely at the start page. To avoid this, start the calibration and then cancel it
immediately. After a two minute wait time, the procedure can be started again. Once the
two minute countdown is complete, the calibration can be completed as normal. This
issue only affects the first attempt per power cycle, so if the calibration must be attempted
again, this process does not need to be repeated.
7. Upon instruction to turn, lift the aircraft off the ground and maintain a level orientation.
a) While the aircraft is hovering, make a heading change of approximately 30° to the right (i.e.,
clockwise).
b) After turning by approximately 30°, the aircraft should be set back down on the ground.

NOTE
Due to the difficulties in executing smooth, accurate turns the GMC 605 display may
incorrectly interpret a station and instruct to “HOLD AIRCRAFT FOR n SECONDS”
before full completion of a 30 turn. If this scenario is encountered, it is best for the
operator to ignore the “HOLD AIRCRAFT FOR n SECONDS” command and instead use
outside references to complete the approximate 30 of turn. Instead of using the GMC 605
display instruction to turn as a real-time indication of when to turn, simply judge the 30°
(±5°) turn increments of the aircraft by using the compass rose radials. Dwelling at these
30 increments for the time recommended by the GMC 605 display should result in
successful calibration.

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 8. The GMC 605 display guides the operator to dwell at multiple headings around a complete circle.

NOTE
Due to high winds or excessive airframe vibration, the operator may encounter a
condition where the GMC 605 display restarts the 18-second countdown without full
completion of the previous countdown. If this is encountered more than once for a given
station, the operator should begin turning to the next station (approximately 30). A
minimum of 2 successful stations per quadrant is required, where a successful station is a
full 18-second countdown followed by instruction to move. Make sure that if stations are
skipped, at least a minimum of 2 stations per quadrant are completed. Thus, it may
sometimes be required to dwell at a station after a countdown restart. A maximum of 30
stations are allowed for the entire calibration procedure. If too many countdown restarts
are encountered, the calibration will fail with the message “TEST FAILED: TOO MANY
STATIONS AROUND COMPASS ROSE”.
9. Repeat the turn-and-stop process until the GMC 605 display instructs the operator that a successful
calibration is complete.
10. Press the ENTER key on the GMC 605 display to conclude this procedure.

NOTE
A magnetometer calibration failure is indicated by a “TEST FAILED: <specific failure>”
message. In the event of a failure, verify the installation passes the Magnetometer
Interference Test procedure of the GSU 75 ADAHRS Installation Manual, Garmin part
number 190-01639-00, and (if needed) move the aircraft to a different location and
attempt the magnetic calibration again.
3.10.2.6 Calibration Procedure F: Servo Post Installation Checkout (GMC 605H units only)
Servo Post Installation Checkout:
1. Enter configuration mode and navigate to the Test>Servo page.
2. This page allows the verification of any servo beep, FTR, or AP disconnect discrete press. The
screen will indicate per axis the discrete pressed. This allows the installer to verify all connections
are in order before continuing to further tests. Any number of discretes can be pressed at the same
time and they all will be indicated on the screen.
3. Exit the page by selecting END TEST and pressing the CONTINUE key.

Figure 3-26 Test Servo Page

3.10.2.7 Calibration Procedure G: Magnetometer Interference Test (GMC 605H units only)
See the GSU 75 ADAHRS Installation Manual (190-01639-00) for this procedure.

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3.10.2.8 Calibration Procedure H: Automated Slip Clutch Test
The servo slip clutch test was developed for GSA80/81/80 highspeed servos, which are used in tandem
with GSM85(A)/86 gearboxes containing a mechanical slip clutch. The test serves as an automated
method to verify the servos can be overpowered in the event of a jam in the gearbox that would otherwise
lock the control surfaces of the airplane. The test passes if the minimum and maximum torques reported
while slipping each axes’ clutch are within 94.17% and 112%, respectively, of the configured mechanical
torque limits.

NOTE
The automated slip clutch test is only applicable to installations containing
GSA80/81/80HS servos. The test start page will indicate the test is unavailable on any
axis that doesn’t contain one of those servos.

1. The following conditions must be true to run this test:

a) The aircraft is on the ground, and stationary
b) The aircraft contains at least one GSA80/81/80HS servo
c) The servos have all passed their internal preflight checks
d) The aircraft-specific configuration/gains files have all been loaded correctly
2. Navigate to the GFC > Servos > TST page (monochrome display units) or to the GFC > Servos >
Selected Servo > TEST page (color display units).
3. Navigate through each axis and verify the test is available to run on all axes containing a
GSA80/81/80HS.

NOTE
Note that some installations will not contain servos on all axes.
4. On any axis’ TST/TEST page, click “TEST ALL”
5. The test will begin running on each installed axis, in both directions, in the following order:
a) Pitch up
b) Pitch down
c) Roll left
d) Roll right
e) Yaw left
f) Yaw right
g) Pitch trim up
h) Pitch trim down

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 6. The automated test sequence for each axis is described below. Each of these states is reflected on
the display by the prompt in (parentheses):
a) The servo is commanded to move at its configured max speed until it runs up against the
mechanical stop. (MOVING CONTROLS TO STOP)
b) Once it hits the stop, it slows the speed to 2.5 RPM, and waits 3 seconds for the measuring
sensors to settle. (INITIALIZING TEST)
c) The software records torque measurement data for 25 seconds. (TAKING DATA)
d) The software commands the servo to stop while it calculates pass/fail for this axis / direc-
tion. (CALCULATING RESULTS)
e) Steps a-d are repeated for the next direction/axis. After steps a-d are completed for all the
axes, the final test results are displayed.

NOTE
During the test sequence, the user can view the currently reported measurements by
scrolling the wheel up. The user can cancel the running test by scrolling the wheel down
and clicking the “CANCEL TEST” button, or by holding the controls firmly and pressing
AP_DISCONNECT

CAUTION
Pressing AP Disconnect while not holding the controls may damage the controls.

7.
a) For Monochrome Display Units: Once completed, the display prompt on the results page
will read TEST RESULTS CALCULATED. The color of the LEDs indicates whether the
test passed, failed, or aborted due to a problem. Scroll up to view the minimum and
maximum torques seen on each direction/axis. When ready to exit the test, hold the controls
firmly, press AP_DISCONNECT, then scroll down and click the “EXIT TEST” button.
b) For Color Display Units: Once completed, the display will show a screen indicating that
the test is complete and that a restart is required. Scroll up one page (TRO page) to view
minimum and maximum torques for each direction/axis. When ready to exit the test, scroll
down to the CTL page and select RESTART. The unit will restart and display a screen
indicating the results of the test. A yellow annunciation indicates that one or more axes
failed while a green indication indicates they all passed. Once satisfied with the results,
press FLC/IAS to start the unit again and boot into Configuration mode.

CAUTION
Pressing AP Disconnect while not holding the controls may damage the controls.

a) Green: all axes PASSED

b) Red: one or more axes FAILED*
c) Yellow: the test encountered a problem (or was canceled) and aborted.

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 NOTE
If the test aborts after completing on one or more axes where the torques were out of
passing range, the end result will be Red for fail instead of Yellow for abort.

8. After pressing and releasing AP_DISCONNECT, the software will command the servos to reset.

3.10.2.8.1 Slip Clutch Test Unavailable Conditions

Table 3-18 lists the conditions that would cause the slip clutch test to be unavailable to start, and the
annunciation that will appear on the display if they occur.

Table 3-18 Slip Clutch Test Unavailable Conditions

Error Condition Annunciation

System is airborne AIRBORNE STATUS
No servo configured on axis AXIS NOT CONFIGURED
Servo on axis has no slip clutch NO SLIP CLUTCH ON AXIS
Servo is offline SERVO OFFLINE
Servo PFT in progress SERVO PFT IN PROGRESS
Servo PFT failed SERVO PFT FAILED
System gains are invalid GAINS MISMATCH
Other/unknown error UNKNOWN ERROR

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3.10.2.8.2 Slip Clutch Test Error Conditions
Table 3-19 lists potential error states for the test and the annunciation that will appear on the display if they
occur. Any of these states causes an abort condition.

Table 3-19 Slip Clutch Test Error Conditions

Error Condition Annunciation

Software can’t verify the aircraft is on the ground
AIRBORNE STATUS
and stationary
Servo under test fails to periodically transmit the
SERVO DATA TIMED OUT
sensor status
Controls stop is not detected within 60 seconds
after the test attempts to move the servo to its STOP NOT REACHED
mechanical stop
Servo under test does not respond to the speed
TEST SPEED INVALID
command within 60 seconds after the test initiates
Any single state of the test exceeds 60 seconds in
SERVO TEST TIMED OUT
duration
System has received a command to cancel the
TEST CANCELLED
test, or AP_DISCONNECT is pressed
While the test is executing the data collection step,
the servo speed is less than 2 RPM or greater TEST SPEED INVALID
than 3 RPM
While the test is executing the data collection step,
the servo torque is less than 70% of the SERVO TORQUE TOO LOW
configured mechanical torque limit
The servo torque is greater than 130% of the
SERVO TORQUE TOO HIGH
configured mechanical torque limit
The servo’s monitor processor has determined the
LOAD CELL/CURRENT MONITOR FAULT
calibration is no longer valid
Servo goes offline during test SERVO OFFLINE

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3.11 Software Loading

NOTE
The GMC 605 is not pre-loaded with the following installation-specific files: aircraft
configuration, gains, audio database, audio configuration, and AHRS configuration.
These files are packaged into an airframe specific loader image, which must be loaded
into the GMC 605 as part of the post-installation configuration and checkout process.

NOTE
Garmin recommends the use of a USB 2.0 compatible flash drive for updating the
GMC 605 databases and software. The flash drive must be formatted as FAT32. Avoid
using card readers, especially those that may require more current than USB 2.0 flash
drives.

NOTE
The USB port is activated during Configuration Mode for use with the USB flash drive. It
is turned off otherwise.

3.11.1 Prepare the GMC 605 Loader Image

1. Go to the Garmin Dealer Resource Center.
2. Download the GMC 605 airframe specific loader image.
3. Make sure that a USB flash drive is connected to the PC.
4. Run the executable file that was downloaded and follow the prompts on the screen to put the
loader image on the USB flash drive.
5. After the loader image has been created, select Finish to complete the process.
6. Eject the USB flash drive from the computer. The USB flash drive is now prepared for uploading
the loader image to the GMC 605.

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3.11.2 GMC 605 SW Upload

NOTE
This functionality is available on both monochrome and color display units. Only
monochrome display screenshots are shown.
1. Document the customer settings under SYS Installation (Section 3.10.1.1.1), GMC Display
(Section 3.10.1.1.3), Remote Display (Section 3.10.1.1.4), and TEST - Audio Volume
(Section 3.10.1.1.7) settings before the software upload.
2. Connect the USB flash drive with the loader image to the GMC 605 using the Garmin USB cable.

NOTE
Use only the Garmin USB cable.

NOTE
The aircraft must not be in motion during a SW load. Motion may trip sensors which will
prevent certain regions from loading, especially during AHRS loads.
3. Enter configuration mode using the CONFIG mode key, see Table 3-8.
4. Navigate to the SW Upload page in config mode (SYS > SW Upload). Select “UPLOAD”, scroll
to highlight, and then press the CONTINUE key again to begin uploading the first set of files from
the loader image in the USB flash drive.

NOTE
If the message “ERROR - USB STICK INCOMPATIBLE” appears on the display, the USB
drive or the USB cable may not be compatible.
5. Once in USB mode, a prompt will ask for a STANDARD or SELECT load (Figure 3-27). Select
STANDARD load. (see Section 3.11.3 for SELECT load instructions if needed)

Figure 3-27 Standard or Select Load Page (monochrome display unit)

6. While the load is proceeding, a progress bar is shown on the display (if the USB flash drive is
equipped with an LED, the LED will begin flashing). After the load completes, the GMC 605 will
display a summary page (Figure 3-28) stating the USB SW upload results. If any items fail, please
view the info screen and note these.

Figure 3-28 SW Upload Results Page (monochrome display unit)

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 7. After the SW upload has been acknowledged, the unit will restart and perform a secondary SW
upload. After the secondary upload is complete, another summary page will state the upload
success status of the secondary upload.
8. Press and hold the CONTINUE key to reboot the GMC 605 into Normal Mode.
9. Power cycle the GMC 605 while holding the “Boot into configuration mode” key to boot into
configuration mode. Verify the SYS Installation (Section 3.10.1.1.1), GMC Display
(Section 3.10.1.1.3), Remote Display (Section 3.10.1.1.4), and TEST- Audio Volume
(Section 3.10.1.1.7) settings match those documented before the software upload.

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3.11.3 GMC 605 SW Selectable Upload

NOTE
Do not perform a Select load on the initial load. Certain load orders are required for the
initial load of a unit.

NOTE
This functionality is available on both monochrome and color display units. Only
monochrome display screenshots are shown.

1. If an item fails to load the first time, using Select loading allows a faster way to load only the data
that failed. Perform steps 1-5 in Section 3.11.2 but choose SELECT instead of STANDARD in
step 4. See Figure 3-27.

NOTE
The SELECT button can be used to toggle back and forth between the Select screen and
the Main screen.
2. Toggle all items that are not needed to show ‘X’. This can be done one at a time or with the Toggle
All button. The desired items should be checked. Depending on the loader card, there may be
items designated with an ‘R’, these are Required loads, so they are not selectable.
3. Toggle all items that are not needed to show ‘X’. All items start checked. Toggling can be done
one at a time by SCROLLING to each item or with the Toggle All button found on the first page,
see Figure 3-15. Depending on the loader card, there may be items designated with an ‘R’. These
are Required loads and are not selectable.

Figure 3-29 Start Load Page (monochrome display unit)

4. Begin at step 6 of Section 3.11.2 and continue with the Standard SW upload.

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3.12 Data Log Download
1. Connect the USB flash drive with enough space to hold the desired data logs using the Garmin
USB cable.

NOTE
The maximum size of all logs is 3GB, but each log will be much smaller. The size of each
log is listed on the display.

NOTE
Use only the Garmin USB Cable.

2. Navigate to the data logs page in config mode (SYS > DATALOGS).

Figure 3-30 A-B Sys/Data Logs Configuration Page (monochrome display unit)

Figure 3-31 A-B Sys/Data Logs Configuration Page (color display unit)

3. Use the date and size (SZ) fields to find which logs to download.

NOTE
The date field will be all zeros if there was no GPS date when the log was created.

NOTE
The newest log is identified as Log 1. Each power cycle is one log and when a new log is
recorded, the identifying number of existing older logs is incremented. All logs must be
downloaded between the selected first and last log (inclusive). To download two
nonconsecutive logs, two separate downloads must be performed.
4. Use the first and last fields to select the logs to download.

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 5. Select the DOWNLOAD button and press the CONTINUE key to start the data logs download.
After the download completes, the GMC 605 will display a summary page stating the download
status.

NOTE
If the message “ERROR-USB STICK INCOMPATIBLE” appears on the display, the USB
drive or the USB cable may not be compatible.
6. Press and hold the CONTINUE key to acknowledge the end of the download.
3.13 Assert Log Download
1. Connect the USB flash drive with enough space to hold the desired data logs using the Garmin
USB cable.

Figure 3-32 Asserts Page (color display unit)

NOTE
Use only a Garmin USB cable, other cables may not be compatible with the GMC 605.

2. Navigate to the assert logs download page in config mode (SYS > ASSERTS).
3. Select the DOWNLOAD ASSERTS text, scroll to highlight, and then press the CONTINUE key to
start the assert logs download.
4. After the download completes, the GMC 605 will display a summary page stating the download
status.

NOTE
If the message “ERROR-USB STICK INCOMPATIBLE” appears on the display, the USB
drive or the USB cable may not be compatible.

5. Press and hold the CONTINUE key to acknowledge the end of the download
3.14 Continued Airworthiness
Maintenance of the GMC 605 is “on condition” only. For regulatory periodic functional checks, refer to
approved aircraft maintenance manuals or manual supplements for actual aircraft maintenance
requirements.

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4 SYSTEM INTERCONNECTS
4.1 Connector Description
The GMC 605 has two 78-pin connectors located at the rear of the unit designated J6051 and J6052 which
are oriented as shown in Figure 4-1. The GMC 605 is installed into a rack with shield block backshells.

011-03295-10

Figure 4-1 Rear View of Backplate

4.2 Pin List

Figure 4-2 Rear Connectors J6051 & J6052, Viewed from Back of Unit

J6051 and J6052 pins are configured as shown in Figure 4-2. J6051 and J6052 pin assignments are listed
in Table 4-1 and Table 4-2.
Following Table 4-1 and Table 4-2, additional tables group pin connections by function. A gray shaded
table row indicates the J6052 connector.
An asterisk (*) following a signal name denotes the signal is active low logic. Active low inputs are
connected to ground to activate. Active low outputs sink current to ground when active.
4.2.1 J6051 Connector
Table 4-1 J6051 Pin Assignments
Pin Pin Name I/O
1 ARINC 429 IN 1 HI IN
2 ARINC 429 IN 1 LO IN
3 ARINC 429 IN 2 HI IN
4 ARINC 429 IN 2 LO IN
5 RESERVED --
6 ETHERNET IN 1A IN
7 ETHERNET IN 1B IN
8 SIGNAL GROUND --

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 Table 4-1 J6051 Pin Assignments
Pin Pin Name I/O
9 SIGNAL GROUND --
10 RS-232 IN 1 IN
11 RS-232 IN 2 IN
12 ANALOG 4 IN Y IN
13 ANALOG 4 IN Z IN
14 RS-485 2A I/O
15 RS-485 2B I/O
16 CONFIG DISC IN 17 IN
17 DISC IN 1 IN
18 CONFIG DISC IN 13 (HV) IN
19 CAN TERM 2 --
20 CAN HI 2 I/O
21 ARINC 429 IN 3 HI ADC 1 IN
22 ARINC 429 IN 3 LO ADC 1 IN
23 ARINC 429 IN 4 HI IN
24 ARINC 429 IN 4 LO IN
25 RESERVED --
26 ETHERNET OUT 1A OUT
27 ETHERNET OUT 1B OUT
28 SIGNAL GROUND --
29 RS-232 OUT 1 OUT
30 RS-232 OUT 2 OUT
31 ANALOG 4 IN X IN
32 CAN TERM 1 --
33 CONFIG DISC IN 12(HV) IN
34 CONFIG DISC IN 14(HV) IN
35 CONFIG DISC IN 18 IN
36 CONFIG DISC IN 2 IN
37 CONFIG DISC IN 11 IN
38 RESERVED --
39 CAN LO 2 I/O
40 ARINC 429 IN 5 HI IN
41 ARINC 429 IN 5 LO IN
42 ARINC 429 IN 6 HI IN
43 ARINC 429 IN 6 LO IN
44 ETHERNET IN 2A IN
45 ETHERNET IN 2B IN
46 ETHERNET OUT 2A OUT

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 Table 4-1 J6051 Pin Assignments
Pin Pin Name I/O
47 ETHERNET OUT 2B OUT
48 SIGNAL GROUND --
49 SIGNAL GROUND --
50 SIGNAL GROUND --
51 ANALOG 3 IN Y IN
52 CAN HI 1 I/O
53 CONFIG DISC IN 10 IN
54 CONFIG DISC IN 15(HV) IN
55 RS-485 3B I/O
56 CONFIG DISC IN 3 IN
57 CONFIG DISC IN 5 IN
58 CONFIG DISC IN 26 IN
59 CONFIG DISC IN 25 IN
60 ARINC 429 OUT 1 HI OUT
61 ARINC 429 OUT 1 LO OUT
62 ARINC 429 IN 7 HI IN
63 ARINC 429 IN 7 LO IN
64 SIGNAL GROUND --
65 SIGNAL GROUND --
66 SIGNAL GROUND --
67 SIGNAL GROUND --
68 AUDIO OUT LO OUT
69 AUDIO OUT HI OUT
70 ANALOG 3 IN X IN
71 CAN LO 1 I/O
72 ANALOG 3 IN Z IN
73 CONFIG DISC IN 16 IN
74 RS-485 3A I/O
75 CONFIG DISC IN 4 IN
76 CONFIG DISC IN 6 IN
77 RS-485 1A I/O
78 RS-485 1B I/O

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4.2.2 J6052 Connector

Table 4-2 J6052 Pin Assignments

Pin Pin Name I/O
1 AIRCRAFT POWER 1 IN
2 RESERVED OUT
3 POWER GROUND 1 --
4 DISC OUT* 2 OUT
5 DISC OUT* 3 OUT
6 RS-232 IN 3 IN
7 RS-232 OUT 3 OUT
8 SIGNAL GROUND --
9 RS-232 IN 7 IN
10 SIGNAL GROUND --
11 HEADING ERROR HI IN
12 HEADING ERROR LO IN
13 COURSE ERROR HI IN
14 COURSE ERROR LO IN
15 FLIGHT DIRECTOR + RIGHT OUT
16 FLIGHT DIRECTOR + LEFT OUT
17 LIGHTING BUS HI IN
18 ETHERNET IN 3B IN
19 ETHERNET IN 3A IN
20 ETHERNET OUT 3A OUT
21 POWER OUT POSITIVE OUT
22 POWER GROUND 2 --
23 CONFIG MODULE CLOCK OUT
24 CONFIG MODULE GROUND --
25 SIGNAL GROUND --
26 SIGNAL GROUND --
27 SIGNAL GROUND --
28 RS-232 IN 6 IN
29 SIGNAL GROUND --
30 SIGNAL GROUND --
31 SIGNAL GROUND --
32 SIGNAL GROUND --
33 SIGNAL GROUND --
34 CONFIG DISC OUT 1 OUT
35 SIGNAL GROUND --
*Active low

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 Table 4-2 J6052 Pin Assignments
Pin Pin Name I/O
36 LIGHTING BUS LO IN
37 SIGNAL GROUND --
38 SIGNAL GROUND --
39 ETHERNET OUT 3B OUT
40 AIRCRAFT POWER 2 IN
41 CONFIG DISC IN 22 IN
42 CONFIG MODULE DATA IN
43 CONFIG MODULE POWER OUT
44 RS-232 IN 5 IN
45 SPARE --
46 RS-232 IN 4 IN
47 RS-232 OUT 6 OUT
48 CONFIG DISC IN 24 IN
49 DISC IN 7 IN
50 LATERAL FLAG IN- IN
51 LATERAL FLAG IN+ IN
52 VERTICAL FLAG IN- IN
53 VERTICAL FLAG IN+ IN
54 FLIGHT DIRECTOR + DOWN OUT
55 FLIGHT DIRECTOR + UP OUT
56 VERTICAL DEV + DOWN IN
57 VERTICAL DEV + UP IN
58 LATERAL DEV + RIGHT IN
59 LATERAL DEV + LEFT IN
60 CONFIG DISC IN 21 IN
61 SPARE --
62 DISC OUT* 4 OUT
63 PPS SEL SINGLE STRAP OUT
64 GPS PPS IN 2 LO IN
65 GPS PPS IN 2 HI IN
66 GPS PPS IN 1 LO IN
67 GPS PPS IN 1 HI IN
68 EXCITATION OUT LO OUT
69 EXCITATION OUT HI OUT
70 DISC IN 23 IN
71 EXCITATION IN HI IN
72 EXCITATION IN LO IN
73 ANALOG 2 IN Z IN
74 ANALOG 2 IN Y IN
75 ANALOG 2 IN X IN
*Active low

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 Table 4-2 J6052 Pin Assignments
Pin Pin Name I/O
76 ANALOG 1 IN Z IN
77 ANALOG 1 IN Y IN
78 ANALOG 1 IN X IN
*Active low

4.3 Aircraft Power

The GMC 605 operates on either 14VDC or 28VDC. After initial power on, the GMC will operate
normally to a minimum of 9 VDC supplied power. Current draw is dependent on I/O usage and output
loading. Power wire gauge should be determined for each specific installation based upon these criteria.
AIRCRAFT POWER 1 and AIRCRAFT POWER 2 are wired together with internal isolating diodes to
provide aircraft power redundancy. The default power connection is through AIRCRAFT POWER 1.
AIRCRAFT POWER 2 may be connected to an alternate power source in aircraft having two independent
electrical buses.
Table 4-3 Aircraft Power

Pin Connector Pin Name I/O

1 J6052 AIRCRAFT POWER 1 IN
3 J6052 POWER GROUND 1 --
40 J6052 AIRCRAFT POWER 2 IN
22 J6052 POWER GROUND 2 --

4.4 Analog Inputs

The GMC 605 includes analog inputs capable of measuring AC waveforms, as well as DC signals. These
inputs may be used with various avionics sensors such as DG heading bugs, HSI course select pointers, and
RVDTs. The Configuration Page enables the interface features needed for various external equipment
such as DGs and HSIs. Here is a signal overview of the three types of analog inputs.
ANALOG 1 IN and ANALOG 2 IN: Two pairs of channels of differential inputs are reserved for future
use. The X input channel and the Y input channel are both measured relative to the Z input. These
differential inputs are intended for connecting across rotary sensors. The amplitude of both DC (-14.45 to
+14.45 VDC) and AC signals (400 Hz through 5000 Hz, amplitudes from 0-10.22 VRMS) may be
measured. The relative phase of AC signals on the X and Y channels may be measured to enable full 360°
determination of position on synchro and resolver interfaces.
ANALOG 3 IN and ANALOG 4 IN: Two pairs of channels of differential inputs are reserved for future
use. These give a processor-independent comparison against ANALOG 1 IN and ANALOG 2 IN. The X
input channel and the Y input channel are both measured relative to the Z input. These differential inputs
are intended for connecting across rotary sensors. The amplitude of both DC (-14.45 to +14.45 VDC) and
AC signals (400 Hz through 5000 Hz, amplitudes from 0-10.22 VRMS) may be measured. Relative phase
cannot be measured.

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 For ANALOG IN inputs 1, 2, 3, and 4, the voltages listed conform to the DO-160 Power Inputs “Abnormal
Operating Conditions”. For voltages that are stable/unchanging when the aircraft power source surges in
amplitude, the channels can accurately read an additional 16.5% above the values listed. The following
limits apply for stable voltages:
VAC (max) = 10.22 * 116.5% = 11.9 VRMS
VDC (max) = +/- 14.45 * 116.5% = +/- 16.8 VDC
EXCITATION IN, HEADING ERROR IN, COURSE ERROR IN: Three pairs of channels of differential
inputs are provided for reading popular HSI and DG interfaces. Each channel’s high side is measured
relative to its low side input pin. These differential inputs are intended for connecting across rotary sensors
such as the variable transformers used in DG such as the Century 52D54 (5000 Hz format) and ARC
G502A (400 Hz format), but they can also read DC signals such as those produced by the King Radio
KI-525 HSI. The amplitude of both DC (-15 to +15 VDC) and AC signals (400 Hz through 5000 Hz,
amplitudes from 0-30.3 VRMS) may be measured. The phase of AC signals (HEADING ERROR IN
relative to EXCITATION IN, COURSE ERROR IN relative to EXCITATION IN) may be measured to
find bug/pointer position relative to the lubber line.

Table 4-4 Analog Inputs

Pin Connector Pin Name I/O

78 J6052 ANALOG 1 IN X IN
77 J6052 ANALOG 1 IN Y IN
76 J6052 ANALOG 1 IN Z IN
75 J6052 ANALOG 2 IN X IN
74 J6052 ANALOG 2 IN Y IN
73 J6052 ANALOG 2 IN Z IN
70 J6051 ANALOG 3 IN X IN
51 J6051 ANALOG 3 IN Y IN
72 J6051 ANALOG 3 IN Z IN
31 J6051 ANALOG 4 IN X IN
12 J6051 ANALOG 4 IN Y IN
13 J6051 ANALOG 4 IN Z IN
11 J6052 HEADING ERROR HI IN
12 J6052 HEADING ERROR LO IN
13 J6052 COURSE ERROR HI IN
14 J6052 COURSE ERROR LO IN
71 J6052 EXCITATION IN HI IN
72 J6052 EXCITATION IN LO IN

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4.5 Excitation Outputs
The EXCITATION OUT pin pair may be configured to provide a differential sine wave signal (400 Hz to
5000 Hz) to differential non-grounded loads such as RVDTs and the Heading Error and Course Error
transducers inside HSIs and DGs. For legacy equipment, this capability is important if the aircraft
electrical system doesn’t provide any source of 400 Hz. Signal amplitudes of up to 6.5 VRMS may be
applied across a resistor load of 100 Ω. Higher impedance inductive loads such as DG transformers may
be driven with 7 VRMS. The EXCITATION OUT amplifier is offset from ground by +8V, and neither of
the output pins may be connected to Aircraft Ground.

NOTE
If used in the installation, the GMC EXCITATION OUT pins must be wired to differential
loads. Connection to ground is not permitted.

Table 4-5 Excitation Outputs

Pin Connector Pin Name I/O

68 J6052 EXCITATION OUT LO OUT
69 J6052 EXCITATION OUT HI OUT

4.6 Audio Output

The audio output is capable of driving 40 mW into a max load of 500 Ω, with bandwidth from 300 Hz to
6 kHz. Pins 68 and 69 provide connection to the internal ground-isolated transformer.

NOTE
NOTE: The GMC Audio Output pins should be wired to differential audio inputs for
highest EMC immunity.

Table 4-6 Audio Out

Pin Connector Pin Name I/O

68 J6051 AUDIO OUT LO OUT
69 J6051 AUDIO OUT HI OUT

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4.7 CAN Bus
This data bus conforms to the ISO 11898 standard for Controller Area Network. Bus wiring must be
twisted shielded pair cable having a controlled impedance of 120 Ω. Total length of the CAN bus network
must be 40 meters or less. Refer to Garmin 190-00313-15, “Controller Area Network (CAN) Architecture
and Installation Practices”.
Due to the high data rate (1 Mbyte/sec) the equipment at the end points of the network must be terminated
using 120 Ω loads. If the GMC 605 is at the end point, connect the CAN TERM 1 to CAN LO 1, and
connect CAN TERM 2 to CAN LO 2.
Table 4-7 CAN Bus

Pin Connector Pin Name I/O

32 J6051 CAN TERM 1 --
52 J6051 CAN HI 1 I/O
71 J6051 CAN LO 1 I/O
19 J6051 CAN TERM 2 --
20 J6051 CAN HI 2 I/O
39 J6051 CAN LO 2 I/O

4.8 Configuration Module (Serial Input/Output)

The Configuration Module Serial Bus provides digital two-wire serial communication to and from the
memory chip that contains installation configuration settings. This memory chip is inside either a
Configuration Module or within the Air Data Module, depending on the aircraft installation. When the Air
Data Module is installed, this serial bus also reads the pitot and static pressure sensors. Power and ground
signals are provided.
The Air Data Module also uses the POWER OUT POSITIVE pin described in Section 4.18.
Table 4-8 Configuration Module

Pin Connector Pin Name I/O

23 J6052 CONFIG MODULE CLOCK OUT
24 J6052 CONFIG MODULE GROUND --
42 J6052 CONFIG MODULE DATA IN
43 J6052 CONFIG MODULE POWER OUT

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4.9 Discrete Inputs, Configurable
The Configurable Discrete Inputs may be individually configured as Active High or Active Low type
discrete inputs. Most inputs are rated for DO-160F A3/B3 indirect lightning transients (“Standard
Voltage”), but four “High Voltage” inputs are rated for A4/B3. The High Voltage (HV) inputs are suitable
for aircraft system connections outside the cockpit.
When configured for the Active Low state, a voltage of 0 to 3.5 V or a resistance of less than 375 Ω to
ground is considered an Active signal. A voltage of 8 V to 36 V or a resistance of greater than 100 kΩ is
considered an Inactive signal.
When configured for the Active High state, a voltage of 8 to 36 V is considered an Active signal. A
voltage of 0 to 3.5 V or open is considered an Inactive signal.
The Configurable Discrete Inputs are designed to source or sink a wetting current to mitigate oxidation that
may exist on switch contacts. Most of the Configurable Discrete Inputs, those with “Standard Voltage”
rating, sink 1mA each when connected to 28V (or sink 0.5mA for 14V) or source 2 mA each when
connected to ground. The remaining “High Voltage” inputs sink 0.5mA each when connected to 28V (or
sink 0.25mA for 14V) or source 1 mA each when connected to ground.
Customers should only connect one GMC Configurable Discrete Input or other receiving input to each
sender (switch or Active Low output). If additional inputs are listening to the sender, the GMC input
resistance may affect readings by those additional inputs when the GMC is off (circuit breaker pulled).
Installers may add a blocking diode in the wiring to remove the effect of this GMC input resistance.
Refer to Figure B-4 for an example of the GTN™ avionics reading the same Go Around switch as the
GMC 605.
Where functional independence is required for an installation’s failure analysis, two of the Configurable
Discrete Inputs are internally routed so they may be read independently by separate GMC processors
(CONFIG DISC IN 21, 22). These have the same properties for as the “Standard Voltage” inputs.
Table 4-9 Discrete Inputs

Pin Connector Pin Name I/O

36 J6051 CONFIG DISC IN 2 IN
56 J6051 CONFIG DISC IN 3 IN
75 J6051 CONFIG DISC IN 4 IN
57 J6051 CONFIG DISC IN 5 IN
76 J6051 CONFIG DISC IN 6 IN
53 J6051 CONFIG DISC IN 10 IN
37 J6051 CONFIG DISC IN 11 IN
33 J6051 CONFIG DISC IN 12 (HV) IN
18 J6051 CONFIG DISC IN 13 (HV) IN
34 J6051 CONFIG DISC IN 14 (HV) IN
54 J6051 CONFIG DISC IN 15 (HV) IN
73 J6051 CONFIG DISC IN 16 IN
16 J6051 CONFIG DISC IN 17 IN

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-10
 Table 4-9 Discrete Inputs

Pin Connector Pin Name I/O

35 J6051 CONFIG DISC IN 18 IN
60 J6052 CONFIG DISC IN 21 IN
41 J6052 CONFIG DISC IN 22 IN
48 J6052 CONFIG DISC IN 24 IN
59 J6051 CONFIG DISC IN 25 IN
58 J6051 CONFIG DISC IN 26 IN

4.10 Discrete Inputs, Active High

The Active High Inputs have the same properties as the Configurable Discrete Inputs when in Active High
mode. All Active High Inputs are rated for DO-160F A3/B3 indirect lightning transients (“Standard
Voltage”). A voltage of 8 to 36 V is considered an Active signal. A voltage of 0 to 3.5 V or open is
considered an Inactive signal. The wetting current for the Active Low mode is not present.
Where functional independence is required for an installation’s failure analysis, DISC IN 23 is internally
routed so it may be read independently by separate GMC processors.
Table 4-10 Discretes In, Active Hi

Pin Connector Pin Name I/O

17 J6051 DISC IN 1 IN
49 J6052 DISC IN 7 IN
70 J6052 DISC IN 23 IN

4.11 Discrete Outputs

The GMC 605 provides three Active Low Discrete Outputs and one Configurable Discrete Output. The
Configurable Discrete Output may be used to drive the validity flag of an analog Flight Director
instrument.
The Active Low Discrete Outputs may be pulled up to an externally sourced supply, VOUT, in the range
0 ≤ VOUT ≤ 33 VDC. In the active state, each Active Low Discrete Output can sink up to 500 mA. In the
inactive state, each Active Low Discrete Output shall present no less than 100 kΩ of impedance between
the output pin and ground.
The Configurable Discrete Output may be configured for one of two formats for the active state: Active
Low and Super Flag (see Table 4-11). For both formats, the inactive state is a high impedance consisting
of more than 100 kΩ between output pin and ground (or Aircraft Power input).
The Configurable Discrete Output includes latching over-current protection. If triggered by a wiring fault,
the fault must be corrected. Once the GMC 605 power is cycled, the intended operation may resume.

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-11
 Table 4-11 Discrete Output Formats

Format Active State Voltage Range

Output may be pulled up to an externally sourced supply,
Active Low Low; can sink ≤ 500 mA
VOUT, in the range 0 ≤ VOUT ≤ 33 VDC
High; ≤ 6 Ω to Aircraft Amplitude of the output voltage is determined by the level of
Super Flag
Power input the Aircraft Power input

Table 4-12 Discrete Outputs

Pin Connector Pin Name I/O

34 J6052 CONFIG DISC OUT 1 OUT
4 J6052 DISC OUT* 2 OUT
5 J6052 DISC OUT* 3 OUT
62 J6052 DISC OUT* 4 OUT
*Active low

4.12 Ethernet
This Ethernet based high speed data bus (HSDB) provides communications capability with the GDU™
display and GTN radios. HSDB meets the hardware aspects of IEEE standard 802.3 for 10 base T Ethernet
communications.
Table 4-13 Ethernet

Pin Connector Pin Name I/O

6 J6051 ETHERNET IN 1A IN
7 J6051 ETHERNET IN 1B IN
26 J6051 ETHERNET OUT 1A OUT
27 J6051 ETHERNET OUT 1B OUT
44 J6051 ETHERNET IN 2A IN
45 J6051 ETHERNET IN 2B IN
46 J6051 ETHERNET OUT 2A OUT
47 J6051 ETHERNET OUT 2B OUT
18 J6052 ETHERNET IN 3B IN
19 J6052 ETHERNET IN 3A IN
20 J6052 ETHERNET OUT 3A OUT
39 J6052 ETHERNET OUT 3B OUT

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-12
4.13 Flight Director Analog Outputs
The GMC 605 provides paired output pins to drive the command bars of analog flight directors. The
installer may select the command bar scale factor that matches the analog flight director. The GMC
outputs may apply voltages from -10 VDC to +10 VDC to the flight director, through a 1 kΩ current
limiting resistor. Flight Director Right and Flight Director Up are driven output pins, while Left and Down
are ground references.
The validity flag of the analog flight director may be driven using the Configurable Discrete Output
described in Section 4.11 Discrete Outputs.
Table 4-14 Flight Director Analog Outputs

Pin Connector Pin Name I/O

15 J6052 FLIGHT DIRECTOR + RIGHT OUT
16 J6052 FLIGHT DIRECTOR + LEFT OUT
54 J6052 FLIGHT DIRECTOR + DOWN OUT
55 J6052 FLIGHT DIRECTOR + UP OUT

4.14 GPS PPS (Pulse Per Second)

The GMC 605 supports both a single ended and a differential PPS signal from the GPS. The single ended
PPS input accepts a 0/5V CMOS logic-level signal. The differential PPS input conforms to the electrical
specifications of the EIA standard RS- 422 receiver.
PPS SEL SINGLE STRAP (J6052-63) sets the PPS reception mode to match the output capability of the
GPS interface. Select differential mode by leaving the PPS SEL SINGLE STRAP unconnected. Connect
PPS SEL SINGLE STRAP output to GPS PPS IN 1 LO input for single ended mode for GPS 1. Similarly,
connect PPS SEL SINGLE STRAP to GPS PPS IN 2 LO for single ended mode for GPS 2.
Table 4-15 GPS PPS

Pin Connector Pin Name I/O

63 J6052 PPS SEL SINGLE STRAP OUT
66 J6052 GPS PPS IN 1 LO IN
67 J6052 GPS PPS IN 1 HI IN
64 J6052 GPS PPS IN 2 LO IN
65 J6052 GPS PPS IN 2 HI IN

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-13
4.15 Lighting Bus
The GMC 605 can be configured to track a 5 VAC, 5, 14, or 28 VDC lighting bus using these inputs. The
lighting bus voltage is used as a reference to control the brightness of the GMC display backlight, LED
annunciators, and keypad backlight. Alternatively, the GMC 605 can be configured to track a photocell in
which case the lighting bus inputs are not used.
Table 4-16 Lighting Bus

Pin Connector Pin Name I/O

17 J6052 LIGHTING BUS HI IN
36 J6052 LIGHTING BUS LO IN

4.16 Navigation Analog Interfaces

The GMC 605 provides a complete set of analog navigation inputs compatible with typical navigation
radios. The GMC measures Lateral (VOR/LOC) and Vertical (Glideslope) validity flags and deviation
signals.
The GMC 605 Lateral Flag and Vertical Flag Inputs are compatible with both the low level flag and Super
Flag navigation radio outputs.
When wired for low level flag outputs, the input impedance measured from Flag Hi relative to Flag Lo is
approximately 1 kΩ. The inputs are differential and able to work with radios having DC offset outputs.
The received signal is considered valid when the differential measurement is 180 mV or more (Flag Hi
relative to Flag Lo).
When wired for Super Flag outputs, the input impedance measured from Flag Hi relative to ground is
approximately 26.5 kΩ. The electrical format is the same as the Active High Inputs. A voltage of 8 to 36
V is considered an Active signal. A voltage of 0 to 3.5 V or open is considered an Inactive signal.
The GMC 605 Lateral and Vertical Deviation Inputs are compatible with navigation radio outputs for
VOR/LOC and GS. The input impedance measured from +IN relative to -IN is approximately 1 kΩ. The
inputs are differential and able to work with radios having DC offset outputs. The VOR scale factor is 15
mV/°. The LOC scale factor is 60 mV/°. The GS scale factor is 214 mV/°.
Table 4-17 Navigation Analog Interfaces

Pin Connector Pin Name I/O

50 J6052 LATERAL FLAG IN- IN
51 J6052 LATERAL FLAG IN+ IN
52 J6052 VERTICAL FLAG IN- IN
53 J6052 VERTICAL FLAG IN+ IN
56 J6052 VERTICAL DEV + DOWN IN
57 J6052 VERTICAL DEV + UP IN
58 J6052 LATERAL DEV + RIGHT IN
59 J6052 LATERAL DEV + LEFT IN

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-14
4.17 Serial Data
4.17.1 ARINC 429
The ARINC 429 output conforms to ARINC 429 electrical specifications when loaded with up to five
standard ARINC 429 receivers. The ARINC 429 output may be programmed to operate at high or low
speed. ARINC input ports are configured per airframe requirements.
The ARINC 429 receivers may accept either high-speed or low-speed data. With one exception, ARINC
429 IN 3 ADC 1, other systems in the aircraft may be assigned to the receivers in an arbitrary fashion. The
signals for this external ADC are routed internally to two independent GMC processors.

Table 4-18 ARINC 429

Pin Connector Pin Name I/O

1 J6051 ARINC 429 IN 1 HI IN
2 J6051 ARINC 429 IN 1 LO IN
60 J6051 ARINC 429 OUT 1 HI OUT
61 J6051 ARINC 429 OUT 1 LO OUT
3 J6051 ARINC 429 IN 2 HI IN
4 J6051 ARINC 429 IN 2 LO IN
21 J6051 ARINC 429 IN 3 HI ADC 1 IN
22 J6051 ARINC 429 IN 3 LO ADC 1 IN
23 J6051 ARINC 429 IN 4 HI IN
24 J6051 ARINC 429 IN 4 LO IN
40 J6051 ARINC 429 IN 5 HI IN
41 J6051 ARINC 429 IN 5 LO IN
42 J6051 ARINC 429 IN 6 HI IN
43 J6051 ARINC 429 IN 6 LO IN
62 J6051 ARINC 429 IN 7 HI IN
63 J6051 ARINC 429 IN 7 LO IN

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-15
4.17.2 RS-232
The RS-232 outputs conform to EIA Standard RS-232C with an output voltage swing of at least ± 5V
when driving a standard RS-232 load.
Table 4-19 lists some limitations and capabilities that affect assignment of the RS-232 receivers to other
systems within the aircraft. Default assignments are shown in parentheses but they may be ignored,
depending on the installation:

Table 4-19 Receiver Comments

Pin Name Comment
RS-232 IN 1 (AHRS 1) Receiver/Transmitter pair. Routed only to Main processor.
RS-232 IN 2 (AHRS 2) Receiver/Transmitter pair. Routed only to Main processor.
RS-232 IN 3 (ADC 1) Receiver/Transmitter pair. Routed only to Main processor.
RS-232 IN 4 (MapMx 1) Receiver only. Routed to internal AHRS processor.
RS-232 IN 5 (MapMx 2) Receiver only. Routed to internal AHRS processor.
RS-232 IN 6 (AHRS 3) Receiver/Transmitter pair. Routed only to Display processor.
RS-232 IN 7 (AHRS 4) Receiver only. Routed only to Display processor.

Table 4-20 RS-232

Pin Connector Pin Name I/O

10 J6051 RS-232 IN 1 IN
29 J6051 RS-232 OUT 1 OUT
11 J6051 RS-232 IN 2 IN
30 J6051 RS-232 OUT 2 OUT
6 J6052 RS-232 IN 3 IN
7 J6052 RS-232 OUT 3 OUT
46 J6052 RS-232 IN 4 IN
44 J6052 RS-232 IN 5 IN
28 J6052 RS-232 IN 6 IN
47 J6052 RS-232 OUT 6 OUT
9 J6052 RS-232 IN 7 IN

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-16
4.17.3 RS-485
The GMC 605 contains a total of three channels of RS-485 serial data communications. These data busses
conform to EIA standard RS-485. Primary servo bus RS-485 1A/1B must be wired to servos in all
installations. Secondary servo bus RS-485 2A/2B must be wired to servos where required by the aircraft
model STC/TC. The third bus, RS-485 3A/3B, is available for receiving RS-422 magnetometer readings
from a GMU 44 or equivalent, as required in rotorcraft installations.
Table 4-21 RS-485

Pin Connector Pin Name I/O

77 J6051 RS-485 1A I/O
78 J6051 RS-485 1B I/O
14 J6051 RS-485 2A I/O
15 J6051 RS-485 2B I/O
74 J6051 RS-485 3A I/O
55 J6051 RS-485 3B I/O

4.18 Power Out

The GMC 605 provides power to the Air Data Module using the POWER OUT POSITIVE pin. This pin
supplies nominal +15.8 VDC to the Module.

Table 4-22 Power Out

Pin Connector Pin Name I/O

21 J6052 POWER OUT POSITIVE OUT

190-01488-01 GMC 605 Installation Manual

Rev. 12 Page 4-17
APPENDIX A Outline & Installation Drawings

CENTER OF GRAVITY LOCATIONS AIRCRAFT FRONT PANEL SURFACE

CONFIGURATION X Y Z .675 17.1

WITHOUT AIR .125 3.2

DATA MODULE 4.2 3.1 0.8

WITH AIR DATA

MODULE 4.5 3.2 0.8

6.30 160.0
RACK
SEE NOTE 4

Y
(CENTER
OF
GRAVITY)

.81 20.4 X (CENTER OF GRAVITY)

7.85 199.4
9.24 234.6
AIR DATA MODULE STATIC FITTING
9.61 244.1
1/8-27 ANPT FEMALE THREAD
1.625 41.28 RACK BODY
2X .800 20.32 2X 1.675 42.55 2X .050 1.27 NOT INCLUDING DIMPLES
SEE NOTE 4

1.650 41.91
BEZEL

Z
6.250 158.75 BEZEL 4X .437 11.10 2X .050 1.27 P6051 P6052
(CENTER OF 6X NOTE 3
GRAVITY) AIR DATA MODULE PITOT FITTING
2X 7.000 177.80
1/8-27 ANPT FEMALE THREAD
2X .406 10.31 SEE NOTE 4

NOTES:
1. DIMENSIONS: INCHES[mm]. METRIC VALUES ARE FOR REFERENCE ONLY.
2. DIMENSIONS ARE NOMINAL AND TOLERANCES ARE NOT IMPLIED UNLESS SPECIFICALLY STATED.
3. MOUNTING HOLES ARE FOR #6 FLAT HEAD 100° CSK SCREWS (6 PLACES).
4. ORIENT CONNECTOR BACKSHELLS WITH THE GARMIN LOGO FACING UP. ORIENT AIR DATA MODULE WITH
THE PITOT AIR FITTING NEAR THE CENTER OF THE GMC 605.

Figure A-1 Outline Drawing

190-01488-01 GMC 605 Installation Manual
Revision 12 Page A-1
APPENDIX A Outline & Installation Drawings

GMC AIR DATA MODULE KIT

(OPTIONAL)
011-04426-00
NOTE 3
325-00496-00
011-04426-01
211-60234-10
NOTE 2
2 PLACES

GMC 605
BACKPLATE KIT
011-03295-10

115-01963-10
GMC 605
211-60234-08 CONNECTOR KIT
NOTE 2 011-03296-00
4 PLACES NOTE 1
212-00024-04 011-01169-01
2 PLACES
233-00087-00
011-00950-04
2 PLACES
330-00185-78
2 PLACES
211-63234-11
4 PLACES

GMC 605 RACK

115-01918-10

NOTES:
1. REFER TO 190-00313-09 FOR ADDITIONAL PARTS LIST.
2. SCREWS SHOULD BE PARTIALLY INSTALLED SO THE SCREW HEADS PASS
THROUGH THE KEY HOLES IN THE BACK OF THE RACK
3. BACKPLATE MUST BE SECURED TO THE RACK BEFORE INSTALLING THE
GMC 605 UNIT AIR DATA MODULE.
011-02967-( )

Figure A-2 Installation Drawing

190-01488-01 GMC 605 Installation Manual
Revision 12 Page A-2
APPENDIX A Outline & Installation Drawings

OPTION 1:
STACK CUTOUT (RACK INSTALLED 6.310 160.27 MIN
FROM FRONT OF AIRCRAFT PANEL)

OPTION 2: 1.685 42.80 MIN

RADIO CUTOUT (RACK INSTALLED
FROM FRONT OF AIRCRAFT PANEL)

4X R.06 1.60 6.310 160.27 MIN

.060 1.52 .060 1.52

OPTION 3: 2X .300 7.62

RADIO CUTOUT (RACK INSTALLED
FROM BACK OF AIRCRAFT PANEL 1.630 41.40 UNLESS OTHERWISE SPECIFIED:
ONLY) MAXIMUM AIRCRAFT PANEL 1. DIMENSIONS: INCH [mm]. METRIC VALUES ARE FOR
2X .658 16.71
THICKNESS IS .125 INCH [3.18 mm] REFERENCE ONLY.
2. TOLERANCES:
INCHES mm
.050 1.27
.XX .02 .XX 0.5
4X R.06 1.60 .750 19.05 2.300 58.42 .XXX .010 .XXX 0.25
3. IF THE FRONT LIP OF THE MOUNTING RACK IS BEHIND
THE SURFACE OF THE AIRCRAFT PANEL THE UNIT
2X 6.180 156.97 CONNECTORS MAY NOT FULLY ENGAGE.
4. MAXIMUM AIRCRAFT PANEL THICKNESS IS .125 [3.18].

Figure A-3 Panel Cutout Drawings

190-01488-01 GMC 605 Installation Manual
Revision 12 Page A-3
APPENDIX B Interconnect Drawings

GMC 605 GI 285

(MODE CONTROLLER) (AP ANNUN)
J6051 P6051
P2851 J2851

RS-232 IN 2 11 1 RS-232 OUT 1

RS-232 OUT 2 30 2 RS-232 IN 1
SIGNAL GROUND 50 6 SIGNAL GROUND
S S

J6052 P6052 GMC 605

SEE NOTE 5
AIRCRAFT POWER 1 1 14/28 VDC AIRCRAFT POWER

AIRCRAFT POWER 2 40 PROTECTED AIRCRAFT POWER

SEE NOTE 5
POWER GROUND 1 3 POWER GROUND

POWER GROUND 2 22

LIGHTING BUS HI 17 TO DIMMER BUS

LIGHTING BUS LO 36 TO DIMMER BUS

1. UNLESS OTHERWISE NOTED, ALL STRANDED WIRE MUST CONFORM TO MIL-W-22759/16 OR EQUIVALENT

2. SHIELDED WIRE USED FOR HSDB INTERFACES SHALL BE AIRCRAFT GRADE CATEGORY 5/5E ETHERNET CABLE
(CARLISLEIT P/N 392404).

3. SHIELDED WIRE USED FOR CAN BUS INTERFACES SHALL BE 120Ω

120 CONTROLLED IMPEDANCE CABLE (TENSOLITE/
CARLISLEIT BMS 13-80T01C02G024, CARLISLEIT CAN24TST120 (CIT), CARLISLEIT CAN24TDT120 (CIT), OR EQUIVALENT).

4. UNLESS OTHERWISE NOTED, ALL SHIELDED WIRE MUST CONFORM TO MIL-C-27500 OR EQUIVALENT

5. THE GMC 605 CONNECTOR KIT PROVIDES FOUR PIN CONTACTS THAT ARE COMPATIBLE WITH AWG #18 & #22
WIRE SIZES TO BE USED FOR AIRCRAFT POWER AND GROUND. THE AIRCRAFT_POWER_1
AIRCRAFT_POWER_1 AND AIRCRAFT_POWER_2
PINS ARE CONNECTED TOGETHER INTERNAL TO THE GMC 605, AS ARE THE POWER_GROUND_1 AND POWER_GROUND_2 PINS.
DEPENDING ON THE EXPECTED CURRENT DRAW OF THE GMC 605 IN EACH SPECIFIC AIRCRAFT INSTALLATION,
USE EITHER ONE OR BOTH OF THE POWER (AIRCRAFT_
(AIRCRAFT_POWER_1
POWER_1 AND AIRCRAFT_POWER_2) PINS AND GROUND
(POWER_GROUND_1 AND POWER_GROUND_2) PINS.

6. SYMBOL DESIGNATIONS

TWISTED SHIELDED 3 CONDUCTOR SHIELD

TERMINATED TO SHIELD BLOCK GROUND
S
S

Figure B-1 Power, Lighting Bus, GI 285 Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-1
APPENDIX B Interconnect Drawings

AIR DATA
MODULE

MODULE
CONFIG
GMC 605 CONFIG MODULE OR
(GARMIN MODE CONTROLLER) P6052
AIR DATA MODULE

BLACK
CONFIG MODULE GROUND 24 1 4 GROUND
RED
CONFIG MODULE POWER 43 4 3 VCC

YELLOW
CONFIG MODULE DATA 42 3 1 DATA
WHITE
CONFIG MODULE CLOCK 23 2 2 CLOCK

BLUE
POWER OUT POSITIVE 21 N/A 5 +16V (ONLY APPLICABLE
TO AIR DATA MODULE)

P4001 GNS 430W

LATERAL FLAG IN- 50 24 LAT -FLAG OUT

LATERAL FLAG IN+ 51 23 LAT +FLAG OUT
S S

VERTICAL FLAG IN- 52 30 VERT -FLAG OUT

VERTICAL FLAG IN+ 53 29 VERT +FLAG OUT
S S

VERTICAL DEV +DOWN 56 28 MAIN +DOWN

VERTICAL DEV +UP 57 27 MAIN +UP
S S

LATERAL DEV +RIGHT 58 22 MAIN +RIGHT

LATERAL DEV +LEFT 59 21 MAIN +LEFT
S S

P6051

CONFIG DISC IN 18 35 14 ILS/GPS APPR MODE OUT

(ILS/GPS APPR MODE)

Figure B-2 Config Module, Alt Enc, GNS™ 430W Receiver Interconnect Drawing Example
190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-2
APPENDIX B Interconnect Drawings

GMA35 SL15 GMA GMA GARMIN AUDIO PANEL

GMC 605
GMA350 SL15M 340 347
(MODE CONTROLLER)
J6051 P6051 P3501 P3502 BOTTOM J1 J3471
2 1
AUDIO OUT HI 69 -- 29 T 31 54 UNSWITCHED UNMUTED AUDIO IN HI
AUDIO OUT LO 68 43 -- GND LUG 32 55 UNSWITCHED UNMUTED AUDIO IN LO
S

NOTES:

1 OTHER AUDIO PANEL INPUTS MAY BE USED ONLY IF INPUTS ARE UNSWITCHED UNMUTED.

2 GROUND SHIELD OF AUDIO WIRE AT ONE END ONLY TO PREVENT GROUND LOOP.

Figure B-3 Audio Output Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-3
APPENDIX B Interconnect Drawings

YOKE MOUNTED SWITCH CONNECTIONS

GTN 6XX/7XX
P100X J100X
GMC 605
(MODE CONTROLLER) X REMOTE GO AROUND
J6051 P6051

GO AROUND SW
CONFIG DISC IN 2 36
1N4007
SEE NOTE 1 AP DISCONNECT SW 1 (NORMALLY CLOSED)
DISC IN 1 17 PROTECTED AIRCRAFT POWER

AP DISCONNECT SW 2 (NORMALLY OPEN)

CONFIG DISC IN 11 37

PITCH UP SW
CONFIG DISC IN 5 57

PITCH DOWN SW
CONFIG DISC IN 6 76

TRIM ARM SW
CONFIG DISC IN 4 75

CONTROL WHEEL STEERING SW

CONFIG DISC IN 3 56

NOTES:
1. ADD 1N4007 DIODE AS SHOWN WHEN SWITCH SIGNAL IS APPLIED TO BOTH THE GMC CONFIG DISCRETE IN AND A SECOND LRU.

Figure B-4 Configuration Discrete Inputs Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-4
APPENDIX B Interconnect Drawings

FCS DISC N.O.

(NORMALLY OPEN)

FCS DISC N.C PROTECTED AIRCRAFT POWER

J6051 P6051 (NORMALLY CLOSED)

P83x J83x GFS 83

DISC IN 11 37 SERVO
9 AP DISC
DISC IN 1 17
GMC 605H 21 TRIM_RELEASE
FORCE TRIM RLS

DISC IN 3 56
PITCH BEEP UP

DISC IN 5 57

DISC IN 13 18
ROLL BEEP R
DISC IN 12 33 ROLL BEEP L

DISC IN 6 76
Yaw Damper
DISC IN 16 73 PITCH BEEP DN

DISC IN 26 58 Level

Figure B-5 Rotorcraft Only Configuration Discrete Inputs Interconnect Drawing Example
190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-5
APPENDIX B Interconnect Drawings

GMC 605
(MODE CONTROLLER) J6051 P6051
P871 GSA 87 (ROLL)
RS-485 1 A 77 19 RS 485 1A
RS-485 1 B 78 20 RS 485 1B

S S
P871 GSA 87 (PITCH)
19 RS 485 1A
20 RS 485 1B

S
P871 GSA 87 (PITCH TRIM)
19 RS 485 1A (IF INSTALLED)
20 RS 485 1B
S
NOTE:
REFER TO THE GSA 87 INSTALLATION MANUAL FOR COMPLETE P871 GSA 87 (YAW)
CONNECTIONS INFORMATION. 19 RS 485 1A (IF INSTALLED)
20 RS 485 1B

Figure B-6 GSA 87 Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-6
APPENDIX B Interconnect Drawings

GFS 83
P831 J831
PITCH SERVO
3 CAN HI 1
4 CAN LO 1
S 16 CAN TERM 1

NOTES:
1. THIS DRAWING SHOWS THE CONNECTIONS FOR THE GFS 83 (-00) 5 CAN HI 2
PARALLEL SERVO. 6 CAN LO 2
S 17 CAN TERM 2
2. REFER TO THE GFS 83 INSTALLATION MANUAL FOR CONNECTIONS
FOR ALL MODELS.

3. REFER TO THE GLA 85 INSTALLATION MANUAL FOR CONNECTIONS

FOR ALL LINEAR ACTUATOR MODELS.

P832 J832
GFS 83
ROLL SERVO
3 CAN HI 1
4 CAN LO 1
S

S
5 CAN HI 2
6 CAN LO 2
S

GFS 83
P833 J833
YAW SERVO
3 CAN HI 1
4 CAN LO 1
S

S
5 CAN HI 2
6 CAN LO 2
S

GMC 605 GSU 75

J6051 P6051 P751 J751 AHRS 1
AFCS
CAN HI 1 52
20 CAN HI 1
CAN LO 1 71
19 CAN LO 1
CAN TERM 1 32 S
S 38 CAN TERM 1
CAN HI 2 20
CAN LO 2 39
CAN TERM 2 19 S S

Figure B-7 GFS 83 Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-7
APPENDIX B Interconnect Drawings

GARMIN
GPS400W
GPS500W GNC155XL 429 ROLL STEERING
GNC420W GNS480
GNS530W GNC300XL
GMC 605 GNS430W
(MODE CONTROLLER) P6051
P5001 P4001 P5 P1
ARINC 429 IN 4 HI 23 46 46 5 16 429 ROLL STEERING A
ARINC 429 IN 4 LO 24 47 47 25 15 429 ROLL STEERING B
S 1 2 S

NOTES:

1 FOR 429 ROLL STEERING, CONNECT IN PARALLEL WITH ANY EXISTING CONNECTIONS TO THESE PINS.

2 IF A GPS/NAV SWITCHING RELAY IS INSTALLED, ROUTE 429 ROLL STEERING THROUGH A

SPARE SET OF RELAY CONTACTS SUCH THAT THE 429 BUS IS ONLY CONNECTED WHEN THE
RELAY IS SWITCHED TO THE GPS POSITION.

Figure B-8 ARINC 429 Roll Steering Interconnect Drawing Example

190-01488-01 GMC 605 Installation Manual
Revision 12 Page B-8
APPENDIX B Interconnect Drawings

GTN7XX GPS500W
GPS400W
GTX335/R GPS #1
GNC420W GNS480
GMC 605
(MODE CONTROLLER) J6052 P6052
GTN6XX GNS530W
GNS430W
GTX345/R
(ATTITUDE AIDING)
P1001 P5001 P4001 P1 P3251 2
1
RS-232 IN 4 46 7 56 56 5 8 232 OUT
4
SIGNAL GROUND 26 45 GND GND 23 51 232 GND
GPS 1 S S

1
GPS PPS IN 1 HI 67 3 16 16 19 4 TIME MARK OUT A
3
GPS PPS IN 1 LO 66 22 -- -- 17 26 TIME MARK OUT B
S S

PPS SEL SINGLE STRAP 63 3

GTN7XX GPS500W
GPS400W
GTX335/R GPS #2
GNC420W GNS480
GTN6XX GNS530W
GNS430W
GTX345/R
(ATTITUDE AIDING)
P1001 P5001 P4001 P1 P3251 2
1
RS-232 IN 5 44 7 56 56 5 8 232 OUT
4
SIGNAL GROUND 25 45 GND GND 23 51 232 GND
S S
GPS 2
1
GPS PPS IN 2 HI 65 3 16 16 19 4 TIME MARK OUT A
3
GPS PPS IN 2 LO 64 22 -- -- 17 26 TIME MARK OUT B
S S

NOTES:

1 SPLICE THESE WIRES TO ANY EXISTING WIRES AT THE SOURCE UNITS.

2 DO NOT CONNECT THE SAME SOURCE TO BOTH GMC 605 INPUTS.

3 FOR GNS4XX/5XX SERIES UNITS, THE "TIME MARK OUT B" SIGNAL IS NOT REQUIRED. IN THIS CASE, CONNECT P6052-66 AND/OR P6052-64 TO P6052-63
WITH A JUMPER WIRE, LENGTH NOT TO EXCEED 6 INCHES.

4 IT IS ACCEPTABLE TO USE OTHER 232 PORTS ON THE SOURCE UNITS.

5 FOR FIXED WING INSTALLATIONS: IF ADM OR ADC IS PRESENT, ONE OR BOTH GROUPS OF GPS AIDING SIGNALS ARE OPTIONAL, BUT ARE RECOMMENDED
FOR BEST AFCS PERFORMANCE AND AVAILABILITY.
FOR ROTORCRAFT INSTALLATIONS: ONE ADC AND AT LEAST ONE GPS ARE REQUIRED EQUIPMENT.

Figure B-9 GPS Source Interconnect Drawing Example

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GTN7XX GDU700 ETHERNET

GDU620
GMC 605 GTN6XX GDU1060
(MODE CONTROLLER) 2

J6051 P6051 P1002 P6201 P2

ETHERNET IN 2A 44 4 13 21 ETHERNET OUT A
ETHERNET IN 2B 45 5 14 36 ETHERNET OUT B
ETHERNET OUT 2A 46 13 11 20 ETHERNET IN A
ETHERNET OUT 2B 47 14 12 35 ETHERNET IN B
S S

J6052 P6052

ETHERNET IN 3A 19 17 32 17 ETHERNET OUT A

ETHERNET IN 3B 18 18 33 32 ETHERNET OUT B
ETHERNET OUT 3A 20 15 30 16 ETHERNET IN A
ETHERNET OUT 3B 39 16 31 31 ETHERNET IN B

S S
NOTES:

1. GTN UNITS ARE PREFERRED FOR ETHERNET CONNECTIONS.

2. IT IS ACCEPTABLE TO USE OTHER ETHERNET PORT NUMBERS. REFER TO SECTION 4 FOR PIN ASSIGNMENTS.

3. THE GMC 605 SHOULD CONNECT DIRECTLY TO THE GTN PORTS, AND INDIRECTLY (VIA THE SPARE GTN ETHERNET PORTS)
TO THE GDU.
4. THE GMC 605 SHOULD ONLY BE CONNECTED TO GTN #2 IF THERE IS ALSO A GDU INSTALLED. OTHERWISE CONNECT THE
GMC ONLY TO GTN #1.
5. ONLY ONE ETHERNET PORT IS REQUIRED FOR THE GMC 605 CONNECTION TO THE GDU.
6. SHIELDED WIRE USED FOR ETHERNET INTERFACES SHALL BE AIRCRAFT GRADE CATEGORY 5/5e ETHERNET CABLE
(CARLISLE IT P/N 392404 OR EQUIVALENT).

Figure B-10 Ethernet Interconnect Drawing Example

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GMC 605
(MODE CONTROLLER) GARMIN AIR DATA
GSU75 GDC72 GDC74()
J6051 P6051
1
P751 P721 P741
ARINC 429 IN 3 HI ADC 1 21 21 21 29 ADC 429 TX A
ARINC 429 IN 3 LO ADC 1 22 22 22 30 ADC 429 TX B
S S

NOTES:

1 SPLICE THESE WIRES TO ANY EXISTING WIRES AT THE SOURCE UNITS.

Figure B-11 Garmin Air Data Interconnect Drawing Example

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GMC 605
(MODE CONTROLLER)
J6051 P6051

CONFIG DISC IN 12 (HV) 33 1

(STALL WARN)

CONFIG DISC IN 13 (HV) 18 2 3

(FLAP EXTENDING)

CONFIG DISC IN 16 73 2 3
(FLAP RETRACTING)

NOTES:

1 STALL WARNING DISCRETE INPUT IS CONFIGURABLE. REFER TO MODEL SPECIFIC

ADDENDUM FOR CONNECTION AND CONFIGURATION DETAILS.

2 FLAP EXTENDING/RETRACTING DISCRETE INPUTS ARE CONFIGURABLE. REFER TO

MODEL SPECIFIC ADDENDUM FOR CONNECTION AND CONFIGURATION DETAILS.

3 FLAP EXTENDING/RETRACTING DISCRETES ARE WIRED ONLY WHEN REQUIRED.

REFER TO MODEL SPECIFIC ADDENDUM FOR DETAILS.

Figure B-12 Stall Warning, Flap Extend/Retract Interconnect Drawing Example

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GMC 605
J6052 P6052

EXC OUT HI 69
EXC OUT LO 68

(BLK) VIN
ANALOG 1 IN Y 77 (WHT) VOUT
ANALOG 1 IN X 78
(RED) VREF
ANALOG 1 IN Z 76
S INTERPOSING POSITION
CONNECTOR SENSOR

GMC 605
J6052 P6052

EXC OUT HI 69
EXC OUT LO 68

(BLK) VIN
ANALOG 2 IN Y 74 (WHT) VOUT
ANALOG 2 IN X 75
(RED) VREF
ANALOG 2 IN Z 73
S INTERPOSING POSITION
CONNECTOR SENSOR

NOTES:

1. EITHER ANALOG 1 OR ANALOG 2 MAY BE USED.

2. USE INTERPOSING CRIMP CONNECTOR TO TRANSITION FROM SENSOR’S #30 AWG WIRING TO
LARGER GAUGE WIRING. STRIP SENSOR WIRES BACK 0.3 INCHES AND FOLD OVER FOR BEST
CRIMP FIT INTO CONNECTOR. SEE DETAILED EXAMPLE IN 190-02081-00.
3. POSITION SENSOR DOES NOT PROVIDE BRAIDED SHIELD. TERMINATE SHIELD GROUND AT
GMC 605H END ONLY.
Figure B-13 Position Sensor Wiring Interconnect Drawing Example
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FREE RADAR
GARMIN COLLINS HONEYWELL ALTIMETER
FLIGHT
GRA 55/
RA‐4500 ALT‐4000 KRA 405B
GRA 5500
GMC 605
(MODE CONTROLLER) P1 P1 P1 P4051
52 12 2 B ARINC 429 OUT A
55 11 10 C ARINC 429 OUT B
S S
2

NOTES

1 THE RADAR ALTIMETER TEST INPUT IS ACTIVATED BY EQUIPMENT OTHER THAN THE GMC 605.

THE ARINC 429 TRANSMIT SPEED OF THE FREE FLIGHT RADAR ALTIMETER MUST BE STRAPPED TO MATCH THE
2 GMC 605 RECEIVER PORT SPEED. THE ALTIMETER “429 SPEED SELECT” PROGRAM PIN, P1‐10, MUST BE LEFT
OPEN FOR LOW‐SPEED ARINC 429 OUTPUT (DEFAULT). GROUND THE PIN FOR HIGH‐SPEED OPERATION.

Figure B-14 Radar Altimeter Interconnect Drawing Example

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