Page 3-22 GDU 37X Installation ManualRevision C 190-01054-013.6 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.3.6.1 Generic Non-structural Antenna InstallationFigure 3-25 shows the generic non-structural installation for the ARINC 743 footprint (GA 55A/GA 57X)antenna. The teardrop footprint antennas (GA55, GA56 stud mount) can also be installed in this manner.For mounting the teardrop style antenna (GA 55 or GA56), a doubler plate similar to Figure 3-4 or P/N115-00846-10 can be used with the mounting surface to support the antenna. Rivets used to secure thedoubler plate to the mounting surface are optional in a non-structural installation. Screws, washers, andlocking nuts as shown in Figures C.2.X are required to secure the Teardrop style antenna to the mountingsurface. Torque the locking nuts to 12-15 in-lbs, torque should be applied evenly across all mountingstuds.A doubler plate similar to Figure 3-14, 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.Figure 3-25 Generic Non-structural ARINC 743 Footprint Antenna Installation
