Northern Airborne Technology 802 - Manual (Page 9)

802-009 Switch Panel
SM802 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-2
ENG-FORM: 805-0117.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.2 Cautions
CAUTION:
Do not bundle any lines from this unit with transmitter coax lines. Do not bundle any audio or DC
power lines from this unit with 400 Hz synchro wiring or AC power lines. Do not position this unit or
wiring from this unit next to any device with a strong alternating magnetic field such as an inverter,
or significant audio interference will result .
CAUTION:
In all installations, use shielded cable exactly as shown and ground as indicated. Significant ground loop
and noise problems may result from not following these guidelines. Ensure that the chassis is grounded
to provide proper shield terminations.
Ensure the microphone and headphone jacks are isolated from the airframe ground. Use caution
when routing microphone wiring, as it carries low-level signals prone to coupling from other sources.
Do not take a ground from the instrument panel or similar location that shares a ground return with a
turn and bank, horizon or other motor driven instrument. This may cause the unit to pick up the
sound of the motor as ground loop interference.
2.4.3 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 wiring diagrams in
Section 2.6 as required.
Allow 3" from the end of the shielded wiring to the shield termination. Reference the interconnect drawing
in Section 2.6 for shield termination details. 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 20 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.