Antenna Installation Instructions - Garmin G900X Installation And Maintenance Manual

12.5.9 Preparation of Doubler
a. Use Garmin P/N: 115-00846-10, or refer to Table 12-5 for guidance on selecting the appropriate
doubler drawing based on the thickness of skin at the antenna location. Make the doubler from
2024-T3 Aluminum (AMS-QQ-A-250/5), 0.063" sheet thickness.
b. For installation in aircraft skins of thickness less than 0.051", countersink the rivet holes in the
doubler for use with flush head rivets (MS20426AD4-x).
c. When using Garmin P/N: 115-00846-10 doubler, sixteen rivet holes exist in the part. For
installation of Garmin P/N: 115-00846-10 in skins of thickness between 0.032" and 0.049", only
those identified for use through the skin cutout detail (Figure 12-9) and doubler installation
(Figure 12-12) are required.
12.5.10

Antenna Installation Instructions

a. Refer to Table 12-6 for guidance on selecting the appropriate mounting cutout. Drill or punch the
holes to match the mating part (doubler).
b. Install a doubler plate to reinforce the aircraft skin, as required. Refer to Section 12.6.1 for
doubler preparation and Table 12-6 for additional guidance on the doubler installation. Dimple
aircraft skin when the skin thickness is less than 0.051" for installation of flush head rivets.
Countersink aircraft skin when the skin thickness is between 0.051" and 0.063" for installation of
flush head rivets.
c. For the stud mount teardrop footprint antenna, place install gasket on top of aircraft skin using the
four screw holes to align the gasket. For the through mount teardrop footprint antenna, secure o-
ring in the o-ring groove on the underside of the antenna.
d. Washers and locking nuts are required to secure the antenna. Torque the four #8-32 stainless
steel locking nuts 12-15 in-lbs. Torque should be applied evenly across all mounting studs or
screws to avoid deformation of the mounting area.
e. Ensure that the antenna base and aircraft skin are in continuous contact with the gasket or o-ring,
as appropriate to the antenna model.
f. Seal the antenna and gasket to the fuselage using Dow Corning 738 Electrical Sealant or
equivalent. Run a bead of the sealant along the edge of the antenna where it meets the exterior
aircraft skin. Use caution to ensure that the antenna connectors are not contaminated with
sealant.
Do not use construction grade RTV sealant or sealants containing acetic acid. These sealants may
damage the electrical connections to the antenna. Use of these type sealants may void the
antenna warranty.
G900X/G950 Installation and Maintenance Manual – Garmin GPS WAAS Antenna
190-00719-00
CAUTION
Page 12-11
Revision D