TruTrak EFIS AP (8300-057C) - Manual (Page 4)

Mechanical Installation Considerations
PROGRAMMER INSTALLATION
Mounting Considerations
The EFIS Series unit is designed to mount in the aircraft instrument panel within view and reach of the
pilot. The primary unit location should minimize pilot head movement when transitioning between
looking outside of the cockpit and viewing/operating the EFIS Series unit. Maximum recommended
viewing angle should be no more than 20 deg. The maximum mounting angle the EFIS can accommodate
is 12 degrees longitudinal axis and 0 degrees lateral axis. The location should be such that the EFIS Series
unit is not blocked by the glare shield on top, or by the throttles, control yoke, etc. on the bottom. Use
aircraft installation standards for mounting and support of the EFIS programmer.
Wiring Considerations
Use AWG #24 or larger wire for all connections unless otherwise specified. The standard solder pin
contacts supplied in the connector kit are compatible with up to AWG #18 wire. In cases where some
installations have more than one component sharing a common circuit breaker, sizing and wire gauge is
based on, length of wiring and current draw on units. In these cases, a larger gauge wire such as AWG
#20 may be needed for power connections. Do not attach any wires to the outside of the EFIS or route
high current wires within six (6) inch of the programmer. Ensure that routing of the wiring is not exposed
to sources of heat, RF or EMI interference. Check that there is ample space for the cabling and mating
connectors. Avoid sharp bends in cabling and routing near aircraft control cables. Do not route the COM
antenna coax near any EFIS components.
RFI/EMI considerations
The EFIS programmer is shielded and does not generate any appreciable level of electromagnetic
interference. Moreover, the servo lines (except for power and ground) are low-current and cannot
contribute to RF interference. The servo power and ground lines do have switching currents through
them, but so long as there are no parallel runs of servo power and ground lines with such things as poorly-
shielded antenna lines or strobe light power lines, there is no need to shield the servo harnesses. The
EFIS itself has been internally protected from RF interference and has been tested under fairly extreme
conditions, such as close proximity to transmitting antennas. However, it is always good practice to
insure that such antennas are properly shielded and not routed directly over or under sensitive panel-
mounted electronic equipment. Most problems in this area are the result of improper RF shielding on
transmitting antennas, microphone cables, and the like. The most sensitive input to the autopilot is the
Control Wheel Switch input. This line should not be routed in parallel with transmitting antennas or
other sources of known RF interference. The CWS wire should be shielded with the shield connection to
pin 19 of the autopilot connector or a close suitable ground point.
Pitot and Static Connections
The TruTrak EFIS require connections to the Pitot and static lines, see page 8. The preferred method of
this connection would be tee fittings near the aircraft’s airspeed indicator. The importance of a good
static port and line cannot be overstated. In some cases, problems can be caused by having a large
number of devices connected to a single, insufficient, static port. In other cases, the static line itself is
adequate but there are one or more devices connected to the same line, one of which has a large static
reservoir. A simple remedy for this problem if it occurs is a tee-fitting near the static port, and a dedicated
line to the EFIS only or a dedicated static port close to the autopilot. Obviously, an insufficiently-large
orifice coupled with large static reservoirs can aggravate the problems associated with lag.
TruTrak Flight Systems 2 EFIS Autopilot Installation Manual
April 2009 8300-057 Rev D