Northern Airborne Technology AA38-5xx - Manual (Page 11)

AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop
SM54 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-2
ENG-FORM: 805-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4 Installation Procedures
2.4.1 Cabling and Wiring
All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to
MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.
For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the connector map in
Section 2.6 as required.
Coaxial cable shall be selected in accordance with MIL-C-17 unless otherwise specified. Do not use coax
cable with PVC insulation. Teflon dielectric cable is encouraged at or above VHF frequencies or where
cable runs exceed 8 feet. Note that at VHF frequencies, cables losses due to long cable runs and tight
bends may reduce the ERP (Effective Radiated Power) by greater than 50%.
Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Reference the interconnect drawing in Section 2.6 for shield termination details. Note that
the hood is a "clamshell" hood, and is installed after the wiring is complete. Aircraft harnessing shall
permit the unit to be lowered from the panel for easy access to all side adjustments. Do NOT mount the
unit until all adjustments have been performed.
Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions. Coaxial cables shall be routed separately from existing wire bundles in the
aircraft to minimize electromagnetic coupling effects.
Unless otherwise noted, all wiring shall be a minimum of 24 AWG, except power and ground lines, which
shall be a minimum of 22 AWG. Reference the Interconnect drawing for additional specifications.
Check
that the ground connection is clean and well secured, and that it shares no path with any electrically noisy
aircraft accessories such as blowers, turn and bank instruments or similar loads. Power to this unit must
be supplied from a separate circuit breaker or fuse (fast blow), and not attached to any other circuit
breaker without additional protection. Verify that the selected circuit breaker size and wire gauge are
adequate for the installation using the techniques specified in AC43.13-1B Change 1, Paragraphs 11-47
through 11-51 and 11-66 through 11-69.
2.4.2 Post Installation Checks
2.4.2.1 Voltage/Resistance Checks
Do not attach the AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop until the following
conditions are met.
Check the following:
a) Check P101, pin 1 for +28 Vdc relative to ground.
b) Check P101, pin 20 for continuity to ground (less than 0.5
Ω).
c) Check P101 pins 3, 5, 7 and 9 for continuity to ground (less than 0.5
Ω) when relevant ICS
PTT line is keyed.
For AA38-502, AA38-602 and AA38-802, repeat this process for the same pins in P102.