Installation Instructions

190-01007-A3 GTN 6XX/7XX AML STC Installation Manual
Rev. 4 Page 2-25
2.4.6 Placards and Labels
All placards and labels must be readable in all cockpit lighting conditions. Ambient flood lighting is
acceptable. Placards added as part of the GTN and GMA 35 installation must be displayed in a
conspicuous place and must not be easily erased, disfigured, or obscured. Text height must be a minimum
of 0.10 inch, and the text must contrast with the placard surroundings such that it is easily readable. The
text must be a high-quality, solid-color font of at least 300 DPI (dots per inch). Dot-matrix fonts are
unacceptable.
New circuit breakers and switches installed for the GTN or GMA 35 unit must be labeled as shown in the
applicable interconnect drawing in Appendix E or Appendix F.
2.4.7 Power Distribution
For the purpose of this section, an avionics bus is considered to be any group of circuit breakers fed from
a common source or multiple sources with a remote switch for the intent of controlling the power to
avionics equipment.
2.4.7.1 Circuit Protection
Circuit protection devices for the GTN and GMA 35 must be push-pull manually resettable circuit
breakers (e.g. Klixon 7274 or 7277 Series circuit breakers). Refer to Figure E-4 for GTN circuit breaker
ratings or Figure F-2 for GMA 35 circuit breaker ratings. The circuit breakers must be labeled as specified
in the interconnect diagrams in Appendix E and Appendix F and the circuit breakers must be readily
accessible to the pilot.
A single circuit breaker must be dedicated to the GTN Main and NAV power inputs as shown in
Figure E-4. A single circuit breaker must also be dedicated to the COM input for the GTN 635/650/750.
See Figure E-4 for more information. Do not combine more than one unit on the same circuit breaker.
2.4.7.2 Power Distribution – Single GTN, Aircraft Weight Less than 6000 Pounds
When one GTN is installed in aircraft with a maximum certified gross takeoff weight of less than 6000
pounds, the GTN should be connected to the avionics bus. The NAV/GPS and COM circuit breakers
(Reference Figure E-4) must be connected to the same avionics bus.
When the GTN is the second NAV/COM unit being installed in the aircraft, the GTN should be connected
to the avionics bus. The 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 should be routed
separately from the power and ground wiring for the other NAV/COM. This method, shown in
Figure 2-11, will maximize system redundancy if the ground connection for one radio fails.
Avionics Bus
GTN 6XX/7XX
COM
Ground Plane
Other NAV/COM
Figure 2-11. Power and Ground Distribution -
Single GTN, Aircraft Weight Less Than 6000 lb