190-01115-01 G3X/G3X Touch Installation Manual - GPS/XM Antenna InstallationRev. AC Page 22-2522.6 Non-Structural Mount InstallationThis section provides installation examples and considerations for non-structural mounting of teardrop andARINC 743 footprint antennas. Typical installations may be below a non-metallic glareshield, under thecomposite or fabric skin, or on an external, non-structural surface. Other non-structural installations mayexist, but are not presented in this manual.External mounting of the antenna is preferred, although the antenna can be mounted inside the aircraft.When mounted internally, the antenna does not have to be aligned with the aircraft forward direction, butshould be equal to the aircraft typical cruise attitude.There should be a solid mechanical base in the mounting area for the antenna, and existing surfaces orbrackets may be used with the doubler plate. Alternately, non-structural brackets may be fabricated in thefield as necessary to mount the antenna. Brackets should be made of minimum 0.032” thickness aluminumand should span as short a distance as possible.Some fabric aircraft include aluminum paste in the fabric finishing process, often referred to as “silvercoats”. Presence of thick fabric and/or heavy “silver coats” may degrade the signal strength of the antenna.22.6.1 Generic Non-structural Antenna InstallationFigure 22-25 shows the generic non-structural installation for the ARINC 743 footprint (GA 36, GA 37,GA 55A/GA 57X) antenna. The teardrop footprint antennas (GA 35, GA 55, GA 56 stud mount) can alsobe installed in this manner.For mounting the teardrop style antenna (GA 35, GA 55, or GA 56), a doubler plate similar to Figure 22-4or P/N 115-00846-10 can be used with the mounting surface to support the antenna. Rivets used to securethe doubler plate to the mounting surface are optional in a non-structural installation. Screws, washers,and locking nuts as shown in the outline and installation drawings in Section 22.7 are required to secure theTeardrop style antenna to the mounting surface. Torque the locking nuts to 12-15 in-lbs, torque should beapplied evenly across all mounting studs.A doubler plate similar to Figure 22-11, or P/N 115-00846-00 (ARINC 743 style) can be used with themounting surface to support the antenna. Rivets used to secure the doubler plate to the mounting surfaceare optional in a non-structural installation. Locking nuts are required to secure the ARINC 743 antenna(locking nuts installed on doubler). Torque the four supplied #10-32 stainless steel screws (Garmin P/N:211-60212-20, MS51958-67, or equivalent) evenly across all mounting screws.
