190-01912-00 GIA 64 Installation/User Manual
DRAFT Page 6 - 9
4.2. Cabling and Wiring Consideration
Cabling and wiring must be installed in accordance with AC 43.13-1B CHG 1 Chapter 11, Sections 8
through 13. The following issues must be addressed:
•Do not expose cabling and wiring to chafing
•Avoid sharp bends in cabling and wiring harnesses
•Make sure ample space is provided for cabling and wiring harnesses and connectors to allow
connection and disconnection.
•Do not route cabling and wiring harnesses near electrical noise sources or high current electrical
wiring (such as power lines to DC electrical motors)
•Do not route cabling and wiring harnesses near flight control cables
•Do not route cabling and wiring harnesses near heat sources
•Appropriate wiring should be shielded
•Wiring pigtail lengths must not exceed 3.0 inches
4.3. Bonding
Electrical equipment, supporting brackets, and racks must be electrically bonded to the aircraft's main
structure or a designated aircraft groundplane. Refer to the following documents for acceptable bonding
techniques:
•AC 43.13-1B CHG 1, "Acceptable Methods, Techniques, and Practices - Aircraft Inspection and
Repair", Chapter 11, "Aircraft Electrical Systems"
•SAE ARP 1870A, "Aerospace Systems Electrical Bonding and Grounding for Electromagnetic
Compatibility and Safety"
•A bonding procedure developed and supplied by the aircraft manufacturer (if available)
The electrical bond must achieve direct current (DC) resistance less than or equal to 2.5 milliohms to local
structure where the equipment is mounted. Compliance must be verified by inspection using a calibrated
milliohm meter.
4.4. Cooling Considerations
The GIA 64 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 64 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.
4.5. Mounting Requirements
The GIA 64 mounting surface must be capable of providing structural support and electrical bonding to
the aircraft to minimize radiated EMI and provide protection from High-Intensity Radiated Fields (HIRF).
4.6. Antenna Installation
The GIA 64 does not include antennas for the VHF COM, VOR/LOC, Glide Slope, and GPS RF
Interfaces. All antennas must be installed and bonded in accordance with the manufactures installation
instructions with the addition to the Garmin guidance provided in section 4.6.1.
