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Revision D 190-00607-04
2.3.3 Materials Required but Not Supplied
The GMX 200 equipment is intended for use with standard aviation accessories. See Appendix C for a list
of compatible equipment. The following items are required for the installation:
• Wire (MIL-W-22759/16 or equivalent)
• Shielded Wire (MIL-C-27500 or equivalent)
• 5-Amp Circuit Breaker
• Tie wraps or lacing cord
• #8 Ring Terminals (for grounding)
• AN507 or MS24693 6-32 cadmium-plated carbon steel screws with 100° countersink flat-heads to
secure the mounting tube to the aircraft structure.
• MS51957-42 or MS35206-242 stainless or cadmium-plated steel screw (PHP, 8-32x.312") for
terminating shield drains to shield block.
• MS35338-137 or MS35338-42 stainless or cadmium-plated steel Split Washer (#8, .045" compressed
thickness) for terminating shield drains to shield block.
• NAS1149CN832R or NAS1149FN832P stainless or cadmium-plated steel Flat Washer (#8, .032"
thick, .174"ID, .375" OD) for terminating shield drains to shield block.
• Shield Terminators
• Silicon Fusion Tape
2.4 Installation Considerations
2.4.1 Minimum System Configuration
The minimum GMX 200 installation requires the following items:
• GMX 200 or GMX 200 I/O
• External GPS Navigation sensor
Altitude from GPS Navigation sensor or an altitude encoder is required
for the terrain function.
2.4.2 External Sensors
External serial data sources intended for use with the GMX 200 should be checked for compatibility
before installation. The list of supported devices is located in Appendix C of this manual.
When the GMX 200 is installed with external sensors, these sensors must be installed with manufacturer's
data. Installation of any external sensors is beyond the scope of this manual and STC.
18.104.22.168 Position Source
The GMX 200 uses the configured GPS source as the primary position source. If a GDL 90 is connected,
the GMX 200 will use the GPS position from the GDL 90 as a backup position source (i.e. the GDL 90
position is used only when the primary GPS position is unavailable).
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GMX 200 Installation Manual Page 2-3
190-00607-04 Revision D 22.214.171.124 Altitude Source
The GMX 200 uses altitude for its terrain awareness function and for calculating absolute altitudes for
traffic. Only one type of altitude (GPS or pressure) can be configured for use by the GMX 200. An
external altitude source (either GPS or pressure) is required if any of the following features is configured:
• The GMX 200 terrain awareness function is used (i.e. an external TAWS source is not
• A Ryan TCAD is configured as the traffic source (altitude is only used to calculate the absolute
altitude for traffic).
126.96.36.199.1 GPS Altitude
If the Altitude Type is set to GPS, the GMX 200 uses GPS Altitude for all of its calculations (if pressure
altitude is also available to the GMX 200, it will not be used). If a GDL 90 is connected, the GMX 200
will use the GPS Altitude from the GDL 90 as a second altitude source, and the altitude source with the
highest integrity will be used for all calculations.
188.8.131.52.2 Pressure Altitude
If the Altitude Type is set to Pressure, the GMX 200 uses Pressure Altitude for all of its calculations (if
GPS Altitude is also available to the GMX 200, it will not be used).
2.4.3 Mounting Considerations
The GMX 200 is designed to mount in the avionics stack in the aircraft instrument panel within view and
reach of the pilot. The GMX 200 must be located where the operator will have easy access to the controls
and adequate viewing of the display meeting the installation limitations in section 7.2. The preferred
location would minimize pilot head movement when transitioning between looking outside of the flight
deck and viewing and operating the GMX 200. Reference Figure D-4. A sample diagram of a typical
cockpit front panel view of the GMX 200 is shown in Figure D-2. The GMX 200 should be placed as
high as possible in the radio stack to minimize the shifting of colors on the display. The audio panel
should be the only equipment above the GMX 200.
The standard package includes a mounting tube for ease of mounting, connections, and service of the unit.
Allow an additional 2” clearance to the rear of the mounting tube for routing cables. Mounting tube
details are shown in Figure D-5 and Figure D-6.
2.4.4 Cable and Wiring Considerations
Wiring should be installed in accordance with AC 43.13-1B Chapter 11. When wire separation cannot be
achieved, the following issues should be addressed:
• The cable harness should not be located near flight control cables and control, high electrical
capacity lines or fuel lines
• The cable harness should be located in a protected area of the aircraft
• Do not route cable near high-energy sources
2.4.5 Air Circulation and Cooling
The GMX 200 does not required external cooling, but mounting configuration should not restrict intake
airflow into the duct above the I/O D-sub connector or exhaust airflow out of the exhaust fans. Reference
Figure D-6 for exhaust fan and air duct locations.
2.4.6 Compass Safe Distance
After reconfiguring the avionics in the cockpit panel, if the GMX 200 is mounted less than six inches
from the compass, recalibrate the compass and make the necessary changes for noting correction data.
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GMX 200 Installation Manual Page 3-1
190-00607-04 Revision D
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 return shipments. 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 Special Tools Required
A crimp tool meeting MIL specification M22520/2-01 and a positioner/locator are required to ensure
consistent, reliable crimp contact connections for the rear D-sub connectors. Refer to Table 3-2 for a list
of recommended crimp tools.
3.3 Equipment Mounting
3.3.1 Mounting Tube Installation
Use the dimensions shown in Figure D-6 to prepare the mounting holes for the GMX 200. You may also
use the GMX 200 mounting tube itself as a template for drilling the mounting holes. Care must be taken
when installing the mounting tube to ensure you can properly insert and secure the unit.
Secure the mounting tube to the avionics stack using the sixteen flat head screws specified in Section
2.3.3. The mating holes in the avionics stack must also be countersunk to accept the screw head so that
the screw head is flush with the inside surface of the mounting tube or adjoining radios.
Failure to properly countersink the mounting holes will result in damage to the GMX
200. Mounting screw heads must not protrude into the mounting tube.
Ensure the mounting tube is flush to the instrument panel and allow sufficient clearance for
the back of the bezel of the GMX 200 to mount flush to the mounting tube. Sufficient
clearance must exist in the instrument panel opening to allow ease of insertion and removal
of the GMX 200.
If the back of the GMX 200 bezel does not mount flush to the mounting tube, connectors
may not engage fully.
Cable assemblies may be attached to the mounting tube before or after the mounting tube is
installed in the avionics stack. Be sure to use the specified flat head screws so the unit will slide
in and out freely. Attach the front of the mounting tube to the stack. Use support brackets to
attach the rear of the tube to the aircraft.
Slide the unit into the tube and hand-tighten the threaded screw shaft using a 3/32" hex. The unit will be
pulled into the tube by the shaft, and the connectors will fully engage. The back of the bezel must be flush to
the mounting tube.
To remove the unit from the mounting tube, unscrew the screw shaft. The unit will be loosened and then
may be pulled from the tube. No special extraction tools are required.
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3.3.2 Unit Replacement
Whenever the GMX 200 is removed and reinstalled, verify that the GMX 200 unit power-up self-test
sequence is successfully completed and no failure messages are annunciated. If the unit was serviced or if
a different unit is being installed, verify that the configuration is correct using the previously completed
checkout log prior to verifying that the GMX 200 unit power-up self-test sequence is successfully
completed and no failure messages are annunciated.
The installation configuration settings are stored in the configuration module and will be
retained when the GMX 200 is replaced with a new unit. However, user settings are
stored on the SD card and will be lost when the GMX 200 is replaced with a new unit,
unless the SD card from the removed unit is installed in the new unit.
3.4 Cabling and Wiring
The GMX 200 installation kit includes connectors and crimp contacts. Make the crimp connections with a
crimp tool as specified in Table 3-2.
Refer to the interconnection diagrams in Appendix E for the appropriate interconnections. Use 22 or 24
AWG wire for all connections except for power. Use 20 AWG for power/ground. Install the
configuration module as described in Section 184.108.40.206. Once the cable assemblies have been made, attach
the backshell/connector to the rear of the mounting tube. Route the wiring bundle as appropriate. Avoid
3.4.1 Wiring Harness
Allow adequate space for installation of cables and connectors. The installer supplies and fabricates all of
the cables. All electrical connections are made through a 37-pin D-Subminiature connector (and 62-pin
D-subminiature connector for the GMX 200 I/O) provided by Garmin. Construct the wiring harness
according to the information contained in this and the following sections. Cable lengths will vary
depending upon installation. Strip all wires going to the connectors 1/8”. Insert the wire into the pin and
crimp with one of the recommended (or equivalent) crimping tools. Insert the pin into the connector
housing location as specified by the interconnect drawing in Appendix E. Verify the pin is properly
engaged into the connector by gently tugging on the wire. Route and secure the cable run from the GMX
200 to the other units away from sources of electrical noise.
Section 4 provides I/O definition of all input and output signals. Required connectors and associated
hardware are supplied with the connector kit(s). See Appendix E for interconnect wiring diagrams.
Check wiring connections for errors before inserting the GMX 200 into the tube.
Incorrect wiring could cause component damage.
Table 3-1. Socket Contact Part Numbers
37-pin connector (P2001) 62-pin connector (P2002)
 22-28 AWG
Garmin P/N 336-00022-00 336-00055-00
Military P/N M39029/63-368 M39029/57-354
AMP N/A N/A
Positronic N/A N/A
ITT Cannon N/A N/A