Teardrop Footprint Antenna Installation (Ga 55 And Ga 56); Preparation Of Doubler; Teardrop Footprint Antenna Doubler Design And Installation - Garmin G3X Installation Manual

13.4 Teardrop Footprint Antenna Installation (GA 55 and GA 56)

This section describes the structural mounting of the teardrop footprint antenna installation.
An acceptable installation method is to use Garmin P/N: 115-00846-10 doubler plate with the GA 55 or
GA 56 stud mount antennas. Another acceptable method is to fabricate and install one of three doublers
(Figure 13-4, Figure 13-5, and
designs vary only by number of rivets and hole preparation for installation with flush rivets. Table 13-5
provides a summary of design and installation details for selecting the appropriate antenna doubler/
backplate.
Figure 13-7 shows an example of the doubler installed between stringers on the top fuselage skin, just off
centerline. The location should be flat, with no gaps between the skin and doubler, to keep from deforming
the skin during installation.
Table 13-5 Teardrop Footprint Antenna Doubler Design and Installation
Aircraft Skin Thickness
Doubler Design (Figure)
Number of Rivets Required
Type of Rivets Required
Skin Preparation for Rivets
Doubler Preparation for Rivets
Skin Cutout Detail (Figure)
Doubler Installation (Figure)
1
Rivet length determined at installation, dependent on thickness of material (rivet length = grip length +
1.5 * rivet diameter)
Refer to the drawings beginning with

13.4.1 Preparation of Doubler

1. Use Garmin P/N: 115-00846-10, or refer to Table 13-5 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.
2. 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).
3. 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
the rivets identified for use through the skin cutout detail
(Figure 13-11) are required.
G3X Installation Manual - GPS/XM Antenna Installation
Page 13-8
Figure 13-6), depending on the thickness of the skin. The three doubler
0.032" to 0.049"
Figure 13-4
12
1
MS20426AD4-x
Dimple
Countersink
Figure 13-8
Figure 13-11
Figure B-1.1
0.049" to 0.051"
Figure 13-5
16
MS20426AD4-x
Dimple
Countersink
Figure 13-9
Figure 13-12
for Garmin Antenna installation drawings.
(Figure 13-8) and doubler installation
0.051" to 0.063"
Figure 13-6
16
MS20426AD4-x
Countersink
None
Figure 13-10
Figure 13-13
190-01115-01
Rev. L