Garmin GI 275 Installation Manual page 146

4.6.1.3 GMU 11 Mounting in Non-Metallic Wingtip
4.6.1.3.1 Overview
In some installations, it is desirable to mount the GMU 11 Magnetometer in the wingtip of a metal aircraft
that has non-metallic (e.g., fiberglass) wingtip covers. If this is the case, the following requirements must
be met:
• The aircraft must have wingtip navigation lights installed
• Heavy overbraid must be installed over the wiring from the GMU 11 to where the wiring exits the
wingtip
• The overbraid must be terminated at this wingtip exit point using a #10 terminal lug and stud
• The GMU 11 must be mounted to a metal rib that does not enclose a fuel bay
• There must be at least one intermediate rib between the rib that encloses the fuel bay and the rib on
which the GMU 11 is installed
• The GMU 11 mounting bracket must be electrically bonded to the wing using fasteners or rivets
4.6.1.3.2 Overbraid Fabrication and Installation
The length of overbraid required is approximately equal to the length of the GMU 11 service loop
(measured from the wing rib to the collar of connector P111) plus 4 inches.
Refer to Figure 4-30 and Figure 4-31 while completing the following overbraid installation procedure:
NOTE
It is recommended that this procedure is completed prior to terminating wires to connector
P111. If this procedure is completed before assembly of P111, proceed to step 3.
1. Disconnect P111 from the GMU 11.
2. De-pin wires from P111 to facilitate placing overbraid over wire bundle.
3. Slide the overbraid over wire bundle extending from wing rib.
4. Terminate the end nearest the metal wing rib with the overbraid in accordance with one of the two
methods in Section 4.6.1.3.3 using a #8 terminal lug.
5. Secure the overbraid pigtail to the shield block when assembling P111 (refer to Section 4.5).
6. Terminate the end nearest the GMU 11 with the overbraid in accordance with one of the two
methods in Section 4.6.1.3.3 using a #10 terminal lug.
7. Secure the overbraid pigtail to a #10 terminal stud. Refer to Section 4.6.1.3.4 for stud location
instructions.
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Rev. 11
GI 275 Part 23 AML STC Installation Manual
Page 4-45