Installation Instructions

190-01007-A3 GTN 6XX/7XX AML STC Installation Manual
Rev. 4 Page 2-27
2.4.7.5 Power Distribution – Dual GTNs, Aircraft Greater than 6000 Pounds
When dual GTNs are installed in aircraft with a maximum certified gross takeoff weight of 6000 pounds
or greater, each GTN must be installed on a separate avionics bus. If two avionics busses are not available
in the aircraft, install GTN #1 on the main bus and GTN #2 on the avionics bus. Both options are shown
in Figure 2-14. Preferably, GTN# 1 should not be connected to the bus that supplies power to the GTN #2
avionics bus. The GTN #1 NAV/GPS and COM circuit breakers (reference Figure E-4) must be
connected to the same bus, and the GTN #2 NAV/GPS and COM circuit breakers must also be connected
to the same bus.
The GTNs must be grounded at separate ground terminal/stud locations on the aircraft. The power and
ground wiring for GTN #1 must be routed separately from the power and ground wiring for GTN #2,
including no shared connectors. This will maximize system redundancy if the ground connection for one
GTN fails.
GTN 6XX
/7XX
COM
Ground Plane
Avionics Bus 2
OR
GTN 6XX/7XX
COM
Avionics Bus 1
GTN
6XX/7XX
COM
Ground Plane
Avionics Bus
GTN 6XX/7
XX
COM
Main Bus
Figure 2-14. Power and Ground Distribution -
Dual GTNs, Aircraft Weight Greater than 6000 lb
2.4.7.6 Power Distribution – GMA 35 Audio Panel
When a GMA 35 audio panel is installed, it should be connected to an avionics bus. If GTN #1 and GTN
#2 are on separate electrical buses, the GMA 35 must be connected to the same avionics bus as the GTN
that is controlling the GMA 35.
2.4.8 Optional Switch Installation
If optional switches are installed as part of the GTN 6XX/7XX and GMA 35 installation, each switch
installed must meet the following requirements:
• The switch must be labeled as specified in the interconnect drawings in Appendix E.
• The label must be adjacent to the switch.
• The switch must be readily accessible to the pilot.