TruTrak Digiflight II Operating Manual - Manual (Page 10)

9
enter GPSV hold, and the
display will show as below:
Once the VDI has been above
the center by one dot for at least
5 seconds the GPSV mode will
ARM, and the display will
show:
As the VDI passes through
center, the autopilot will couple
to the virtual glide slope, and
the display will show that the
autopilot is now coupled to the
virtual glide slope as below:
Missed approach
Once the Glide Slope is coupled
press any button to activate the
Go Around mode. The
autopilot will pitch up to +500
fpm and will engage TRK mode
on the current track.
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
fast trim it will be necessary to
tap or pulse the trim button so
that it will be slow enough to
turn it off before going too far.
When a reversal takes place, a
slight tap in the opposite
direction may be required to get
the bars to stay off. Finally
when the bars have been made
to disappear and there has been
no speed change, the bars can
be ignored if they reappear in
that it is known the aircraft is
close to being in trim.
Minimum and
Maximum Airspeed
The Digiflight II series
autopilots have a minimum and
maximum airspeed feature.
These are added only for safety.
This feature is easier described
using the Digiflight IIVS model
as an example. If the pilot