TruTrak Digiflight Operation Manual - Manual (Page 6)

5
GPS Acquisition
Between the word
MAG
and
the three digit numeric display,
a flashing period
MAG • 155
will
appear each time the GPS sends
a message to the autopilot (once
per second). This indicates the
GPS is working but has not yet
obtained a position fix. As long
as the period is shown, the
heading display cannot
transition to the
TRK
mode.
When the GPS does obtain
a fix, the period will be
replaced by an asterisk
MAG*155
. This means that
when a certain velocity is
attained
MAG
will be replaced
by
TRK
. This happens at
approximately 10 Knots ground
speed as detected by GPS and
will even occur at rapid taxi
speeds.
Digiflight 100
Lateral Modes
Upon being engaged, the
autopilot will be in the basic
lateral mode, and it will be
synchronized to the direction
being flown at the time. The
number following
SEL
(Selected
direction) is underlined,
meaning that rotation of the
encoder will select heading.
Rotation of the knob when it is
not depressed will cause 5
°
steps of
SEL
and when it is
depressed the steps will be 1
°
.
If a GPS flight plan has
been entered into the GPS,
pushing the small button to the
left of the display will engage
the
GPS NAV
mode and a
flashing plus sign will show. In
the
GPS NAV
mode the autopilot
will follow a flight plan
programmed into the GPS. The
autopilot must, however, over-
fly each way point prior to
turning and intercepting the
next course line.
If the
GPS-S-
option has
been added, pushing the small
button to the left of the display
will engage the GPS steering.
In the
GPS-S-
mode the autopilot
follows lateral steering or bank
commands generated by a
navigation system (EFIS or
GPS).
Magnetic Back-Up
Mode
The lateral modes
previously described are based
on GPS track being present.
When GPS is lost, the DG
TRK+135
GPS -S- AP ON
TRK*135
SEL 135 AP ON
TRK+135
GPS NAV AP ON