Cabling And Wiring; Cooling Air - Garmin GIA 63 Installation Manual

2.4 Cabling and Wiring

Refer to the interconnect examples in Appendix C for wire gauge guidance.
In some cases, a larger gauge wire such as AWG #16, #18, or #20 may be needed for power
connections. Special thin-wall heat shrink tubing is also provided to insulate the extended barrels
inside the backshell. If using AWG #16 or #18 barrel contacts, ensure that no two contacts are
mounted directly adjacent to each other. This minimizes the risk of contacts touching and
shorting to adjacent pins and to ground.
Ensure that routing of the wiring does not come in contact with sources of heat, RF or EMI
interference. Check that there is ample space for the cabling and mating connectors. Avoid sharp
bends in cabling and routing near aircraft control cables.
Coaxial cable with 50 Ω nominal impedance and meeting applicable aviation regulations should
be used for the installation. A typical maximum cable length for the GPS antenna is 40 feet. The
installer shall insure that the attenuation does not exceed 10 dB at 1.5 GHz for the GIA63, and
falls between 3 dB and 7 dB inclusive at 1.5 GHz for the GIA 63W or GIA 63H.
Check that there is ample space for the cabling and mating connectors. Avoid sharp bends in cabling,
particularly the COM antenna cable, and routing near aircraft control cables. Cabling for the GIA 63(X)
should not be routed near components or cabling which are sources of electrical noise. Do not route the
COM antenna coax near any ADF antenna cables. Route the GPS, VOR/LOC, and Glideslope antenna
cables as far as possible away from all COM transceivers and antenna cables.

2.5 Cooling Air

The GIA 63(X) meets all TSO requirements without external cooling. However, as with all electronic
equipment, lower operating temperatures extend equipment life. On the average, reducing the operating
temperature by 15-20 °C (25 to 35 °F) doubles the mean time between failure (MTBF). Recommended
airflow rating is 1 CFM (cubic foot per minute) at a pressure equivalent to 0.1 inches of water. Potential
damage to your GIA 63(X) may occur by using outside forced air to cool the equipment. Therefore, it is
recommended that an electric forced air fan be installed, of the indicated rating, to cool this equipment.
Units tightly packed in the avionics stack heat each other through radiation, convection, and sometimes
by direct conduction. Even a single unit operates at a much higher temperature in still air than in moving
air. Fans or some other means of moving the air around electronic equipment are usually a worthwhile
investment. A 5/8" diameter air fitting is provided on the rear of the mounting rack for the purpose of
admitting cooling air under such conditions. If a form of forced air cooling is installed, make certain that
rainwater cannot enter and be sprayed on the equipment. Refer to the G1000 System Installation manual,
Garmin part number 190-00303-00, for information on cooling requirements.
Page 2-10 GIA 63 Installation Manual
Revision T 190-00303-05