Installation Instructions

GTN 6XX/7XX AML STC Installation Manual 190-01007-A3
Page 2-26 Rev. 4
2.4.7.3 Power Distribution – Dual GTNs, Aircraft Less than 6000 Pounds
When two GTNs are installed in aircraft with a maximum certified gross takeoff weight of less than 6000
pounds, connect GTN #1 to the avionics bus. The NAV/GPS and COM circuit breakers (reference
Figure E-4) for GTN #1 must be connected to the same avionics bus. If a second avionics bus is available,
connect GTN #2 to the second avionics bus; otherwise connect GTN #2 to the same avionics bus as
GTN #1. The NAV/GPS and COM circuit breakers for GTN #2 must be connected to the same avionics
bus.
The GTNs must be grounded at separate ground terminal/stud locations on the aircraft. Power and ground
wiring for GTN #1 should be routed separately from the power and ground wiring for GTN #2, as shown
in Figure 2-12. This will maximize system redundancy if the ground connection for one GTN fails.
Avionics Bus
GTN 6XX/
7
XX
COM
Ground Plane
GTN
6XX/7
XX
COM
Avionics Bus 1
GTN 6
XX/
7XX
COM
Ground Plane
GTN 6
XX/7
XX
COM
Avionics Bus 2
Preferred
Alternate
Figure 2-12. Power and Ground Distribution -
Dual GTNs, Aircraft Weight Less Than 6000 lb
2.4.7.4 Power Distribution – Single GTN, Aircraft Greater than 6000 Pounds
When a single GTN is installed in aircraft with a maximum certified gross takeoff weight of 6000 pounds
or greater, the GTN must be installed on a bus (main or avionics bus) separate from that of other pre-
existing NAV/COM systems in the aircraft, as shown in Figure 2-13. The GTN NAV/GPS and COM
circuit breakers (reference Figure E-4) must be connected to the same avionics bus.
The GTN and other NAV/COM must be grounded at separate ground terminal/stud locations on the
aircraft. The power and ground wiring for the GTN must be routed separately from the power and ground
wiring for the other NAV/COM, including no shared connectors. This will maximize system redundancy
if the ground connection for one radio fails.
Avionics Bus 1
GTN 6XX/7XX
COM
Ground Plane
Avionics Bus 2
Other NAV/COM
OR
Avionics Bus
GTN 6XX/7XX
COM
Ground Plane
Main Bus
Other NAV/COM
Figure 2-13. Power and Ground Distribution -
Single GTN, Aircraft Weight Greater Than 6000 lb