Revision A5 3-21
GRT Avionics HXr Installation Manual
SECTION 3: WIRING CONSIDERATIONS
3.1 General Guidelines
Wires that are certain to be used are pre-installed in the EFIS cable assembly connectors. Optional
connections to the EFIS are not installed in the D-sub connectors at the factory, however, colored
aviation-grade wires with pre-installed D-sub connector contacts are included for these connections.
The cable description diagram includes recommended wire colors for each connection to the EFIS
components.
When routing the wiring, the following guidelines should be considered:
Ÿ
Good practices for physical installation of the wiring should be followed, such as grommets where
wires pass through sheet metal, considering for chaffing and interference with moving
mechanisms, etc.
Ÿ
Cable lengths should include enough extra length to allow for servicing the equipment. For
example, the cables which plug into the display unit should be long enough to allow them to be
connected to display unit with the display unit not installed in the instrument panel.
Ÿ
In general, routing of the wiring is not critical, as the EFIS is designed to be tolerant of the electrical
noise and other emissions typically found in aircraft. Some consideration should be given to avoid
routing wires near antennas, or other locations that could impart high levels of electromagnetic
signals on the wiring.
Ÿ
The checkout procedures outlined in Section must be completed to verify the EFIS is not affected
by radio transmissions on any frequency.
Ÿ
Consider the effects of individual component failures in the design of the system as a whole to
create redundancy where necessary.
3.2 Power Connections
The display units each include 3 isolated power input connections. This allows redundant power
sources, such as a main and secondary bus. The display units consume approximately 1 amp,
making even a small 3 Amp-Hour gel cell a suitable emergency source.
The configuration of the power supplied to the display unit(s) is left to the installer. Considerations
such as the number of power buses, the desire or not to supply one piece of equipment with power
from redundant buses (which in theory allows the possibility of one device affecting both buses),
the configuration of the electrical system with respect to backup equipment, and so on, may dictate
the best configuration for a particular airplane.
No provision is included within the display units for a power switch. If a power switch is desired
for the EFIS, the +12V power should be controlled with the switch (not ground). It is desirable to
have the display units and AHRS off during the engine start if all of the buses which power them
