Figure B-4 Fiberglass Insulation For Carbon Material - Garmin GTX 330D Maintenance Manual

When replacing damaged aluminum foil, the following procedure is recommended for bonding on
composite structures.
1. The aluminum tape must be isolated from carbon composite material. Secure a thin layer of
fiberglass cloth to the carbon fiber with fiberglass resin as shown in figure B-4.
CARBON
FIBER

Figure B-4 Fiberglass Insulation for Carbon Material

2. Ensure the existing ground location is prepared in accordance with section B.2.
3. Route the aluminum tape between the GTX install rack and the grounding location. If needed to
maintain the length-to-width ratio, the tape width can be overlapped in more than one strip. If two
or more pieces of tape must be joined end-to-end, they can be joined as illustrated in figure B-5.
4. Fold the end of the tape over twice for added thickness at the prepared grounding location. The
span of the fold should equal or exceed the width of the aluminum plate used to protect the
aluminum tape from the fasteners.
5. Secure the end of the tape to the composite surface with the existing aluminum plate as shown in
figure B-6.
6. If any of the existing special bonding components are found to be damaged, use the braid and
hardware specified in table B-2 to replace the damaged items (refer to figure B-6 and figure B-7).
7. If multiple strips of tape were used, the plate must touch each strip to ensure grounding.
8. Ensure the bonding straps, aluminum plate, and associated hardware are reinstalled as shown in
figure B-7.
9. Verify the resistance between tape and the local grounding location does not exceed 2.5 mΩ.
10. Reinstall the GTX install rack and aluminum plate on the aluminum tape as shown in figure B-7.
The recommended torque for #6 screws is 12-15 in-lbs and for #10 screws is 20-25 in-lbs.
11. Verify the resistance between the GTX chassis and the aircraft ground structure specified in
table B-1 does not exceed the value specified in table B-1.
190-00734-11
Rev. 6
ALUMINUM TAPE
GTX 33X and GTX 3X5 ADS-B Maintenance Manual
STRIP OF LIGHT FIBERGLASS CLOTH
SUCH AS 1080-50 (1.45 OZ/SQ. YARD)
ATTACHED WITH FIBERGLASS RESIN.
¼" MINIMUM DISTANCE
EACH SIDE.
Page B-5