TruTrak Digiflight Operation Manual - Manual (Page 10)

9
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.
Vertical Modes
When the autopilot is
engaged it will synchronize to
the direction and vertical speed
being flown at the time, the
lower right section of the
display shows SVS (selected
vertical speed). This is shown
below:
If an altitude change is
desired, momentarily push and
release the encoder knob and
the cursor will move over to the
selected vertical speed.
Rotation of the encoder
knob will now change the
selected vertical speed. If the
selected vertical speed is set to
zero, the display will show:
Once the desired vertical
speed has been selected,
momentarily pushing and
releasing the encoder knob will
move the cursor back to
SEL
, or
after approximately seven
seconds without moving the
encoder, the cursor will move
back to
SEL.
Setting Pitch Trim
The pitch servo contains a
torque sensor that sends a signal
to the computer when the up or
down force greater than a
threshold value is required to
fly a selected flight condition.
When this signal indicates an
out of trim condition that
persists in one direction for
more than a pre-set length of
time, the three moving
horizontal bars will come into
view and move according to the
direction in which trim is
required. The pilot is then
required to operate the trim
control (electric or manual) so
as to bring the system to neutral
trim. With mechanical trim this
is easily done, but with electric
systems it may be necessary to
develop a technique. If the trim
is slow enough, the pilot has
plenty of time to react when the
bars disappear before the trim
condition is reversed. With a
TRK*135
SEL 135 SVS 100+
TRK*135
SEL 135 SVS 100+
TRK*135 ALT HOLD
SEL 135 SVS 0