TruTrak DFC Operating Manual User Manual

Page 14

internal magnetic disturbances
within the aircraft, and should
be performed once the autopilot
is installed in the panel of the
aircraft. It may need to be
repeated if the autopilot is
moved within the panel, or if
new equipment is installed
nearby. In order to skip this
step, press and quickly release
the encoder knob while

selected.

If a calibration is desired, it

may be done in either of two
ways: (1) With the autopilot
disengaged, either in the air or
on the ground, the operator will
turn the aircraft through a full
circle according to instructions,
or (2) With the autopilot
engaged, in flight, the autopilot
directs the aircraft in the
necessary flight path.
In either method of
calibration, the aircraft is
turned, first to North, then East,
then South, and finally West. At
each step, the heading is flown
for approximately 20 seconds
while the autopilot gathers and
averages the data from the
magnetometer.

The magnetometer is

initially calibrated at the factory
for operation in an environment
free of magnetic disturbances,
and should be functional,
though not accurate, when
mounted in the aircraft. The
first calibration of the
magnetometer in the actual
aircraft is probably best done on
the ground, on a level pavement
surface, as there are fewer

variables involved than would
be the case in flight. Assuming
that it is desired to perform this
calibration, do the following
steps:
(1) Rotate the encoder knob to

select

in the setup screen.

(2) Press and quickly release
the encoder knob to begin the
setup sequence. The screen will
now show:

CALIBRATING
TURN NORTH

Turn the aircraft to a

heading of North using a
reliable reference, either a
compass or magnetically slaved
DG or HSI. Once this is done,
press and quickly release the
encoder knob to confirm that
the heading is steady. The
screen will now show:

CALIBRATING

HOLD NORTH

After a period of approximately
20 seconds, the screen will
show:

CALIBRATING
TURN EAST

Again, turn the aircraft to a

heading of 090 magnetic and
then press and quickly release
the encoder knob. In the same
manner as before, the screen
will say

HOLD

for twenty

seconds. This process is
continued through South and
West. Once the westerly data