TruTrak Digiflight Operation Manual - Manual (Page 8)

7
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
display is slaved to a magnetic
heading source contained
within the programmer and
TRK
is replaced with
MAG
. This
magnetic mode is only a backup
and would seldom be needed;
however, it does provide a
means of selecting and
maintaining a drift-free
direction of flight. If the
GPS-S-
signal source is functional, the
GPS-S-
mode will remain
functional.
Altitude Hold Mode
When the autopilot is
engaged it will be in the basic
lateral mode, and will
synchronize to the direction
being flown at the time. The
pitch servo will not be engaged
at this time. To engage the
altitude hold the aircraft must
be at the desired altitude and be
trimmed for level flight. After
trimming the aircraft, to enter
the altitude hold mode, simply
press and release the encoder
knob. The display will show:
If an altitude change is
desired, it is necessary to turn
off the altitude hold. To do
this, press and release the
encoder knob. The display will
show:
Gyro Set
When the initializing has
been done correctly, the gyros
should already be centered at
the time of take off. If
confirmation of this is desired,
with the aircraft stationary on
the runway and the autopilot
disengaged, pressing and
holding the encoder knob will
put the gyros in the fast
centering mode. The knob
should be depre ssed for
approximately 7 seconds during
TRK+135
GPS -S- AP ON
TRK*135 ALT HOLD
SEL 135 AP ON
TRK*135
SEL 135 AP ON
TRK+135
GPS NAV AP ON