Installation Instructions

GTN 6XX/7XX AML STC Installation Manual 190-01007-A3
Page G-2 Rev. 4
CAUTION
All overbraid ends must be secured outside the backshell by the strain relief
bar. Failure to do so may allow overbraid ends to contact and short HSDB
pins, resulting in weather radar malfunction or damage.
6. At the bulkhead end of the overbraid (or grounding provisions at the metallic wing entry area),
comb out a maximum of two inches of braid, twist it, cut to length if necessary, and terminate it
in a terminal lug. Refer to Figure G-1.
7. Secure the overbraid pigtail to a terminal stud.
G.1.1.3 Overbraid Terminal Bonding
Electrical bond preparation for all aluminum-to-aluminum interfaces must be done in accordance with
SAE ARP1870 Sections 5.1 and 5.5. The overbraid terminal lug must be electrically bonded to a 5/16”
stud installed in accordance with AC 43.13-1B Section 11-189, as well as the following restrictions:
1. If possible, use an existing tooling hole to install the stud.
2. If no suitable tooling hole exists, use an existing fastener (5/16” or larger).
NOTE
Installation of a stud into a pressure bulkhead is not authorized under this STC. If a new
stud must be installed into a pressure bulkhead, additional approval for installation of the
stud will be required.
3. If there is no suitable fastener, install a new stud as follows:
a) When adding a new stud hole to the bulkhead, the center of the hole must be located a
minimum of one inch away from any existing, non-stiffened hole.
b) The new stud hole must be located such that the terminal lug face, neck, or attaching
hardware will not intrude into the flange bend radius of any edge or stiffened hole.
Refer to MS20659 for terminal lug dimensions.
Verify overbraid terminal bonding by checking resistance between the overbraid and the bulkhead (or the
metallic wing structure for a wing-mounted WXR). Resistance should be less than 2.5 mΩ.