Table 3-3 Bonding Requirements; Aluminum Surface Preparation - Garmin GI 275 Maintenance Manual

The resistance must be verified with a calibrated milliohm meter with ±0.1
all connector(s) disconnected.
LRU
GI 275 Base
GI 275 ADAHRS
GTP 59
GMU 44B
GSB 15
3.5.3

Aluminum Surface Preparation

In order to prepare the aluminum surface for proper bonding, the following general steps should be
accomplished. For a detailed procedure, refer to SAE ARP1870 Sections 5.1 and 5.5.
1. Clean grounding location with solvent.
2. Remove non-conductive films or coatings from the grounding location. When area is cleaned
around fastener heads or washers, the area cleaned should be 0.125 inches wider than the footprint
of the washer or the bolt head.
3. Apply a chemical conversion coat, such as Bonderite M-CR 1200S Aero, to the bare metal.
4. Once the chemical conversion coat is dry, clean the area.
5. Install bonding aluminum tape or equipment at grounding location.
6. After the bond is complete, if any films or coatings were removed from the surface, re-apply a
suitable film or coating to the surrounding area.
190-02246-C2
Rev. 3

Table 3-3 Bonding Requirements

Bonding Requirement
2.5 mΩ (from unit to instrument panel)
2.5 mΩ (from unit to local structure)
2.5 mΩ (from unit to instrument panel or local structure)
GI 275 Part 27 AML STC Maintenance Manual
Ω (or better) accuracy with
m
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