Page 3-10
GTN 625/635/650 TSO Installation Manual
Rev. C
190-01004-02
3.5
GTN 625/635/650 Mounting Considerations
The GTN is designed to mount in the avionics stack in the aircraft instrument panel within view and reach
of the pilot. The primary unit location should minimize pilot head movement when transitioning between
looking outside of the cockpit and viewing/operating the GTN. The location should be such that the GTN
unit is not blocked by the glare shield on top, or by the throttles, control yoke, etc. on the bottom. If
aircraft has a throw-over yoke, be sure the yoke does not interfere with the GTN.
3.6
Cabling and Wiring Considerations
Wiring should be installed in accordance with AC 43.13-1B Chapter 11. For dual GTN unit installations,
care should be taken to ensure separation between wires of redundant systems to reduce the possibility of
loss of navigation due to a single event. When wire separation cannot be achieved, the following issues
should be addressed:
It should not be possible for a cable harness to be exposed to wire chafing in a manner that both
GPS units fail simultaneously;
The cable harness should not be located near flight control cables and controls, high voltage lines
or fuel lines;
The cable harness should be located in a protected area of the aircraft (e.g., isolated from engine
rotor burst); and
Do not route cable near high voltage sources.
NOTE
Pigtail lengths must be less than 3.0 inches. Wiring which is required to be shielded must
be shielded per Appendix D.
Refer to Section 4.8 and Section 4.9 for connector and tooling information.
Refer to Section 4.11 for recommended coax cable.
Refer to Appendix D for the appropriate wiring connections to assemble the wiring connector.
Once the cable assemblies have been made, attach the cable connectors to the rear connector plate. After
installing the mounting tube, attach the assembled connector plate. Route the wiring bundle as
appropriate. Use 22 to 24 AWG wire for all connections except for power. Use 20 AWG for power and
ground. Avoid sharp bends.
