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System Overview
The flight director command bars in a DFC90 autopilot are
designed for easy use and improved performance during
uncoupled autopilot operations.
During coupled operations (both “AP” and “FD” buttons lit),
pressing the “FD” button will have no effect. Pressing the “AP”
button in this state will toggle the “AP” mode on/off. It is a good
way to disconnect the servos but continue to have flight director
command bars present. The recommended way to disengage
both the “AP” and “FD” modes will be via trim or the AP
Disconnect switch on the control yoke as described above.
DUAL PFD OPERATIONS
For those aircraft equipped with dual Avidyne PFDs, either PFD
can drive the DFC90 however; it requires a manual action on the
part of the pilot to select the right-hand PFD to be the attitude and
air data source for the autopilot. There is not an automatic
switchover capability to the right-hand PFD in the event of an
inoperative left-hand PFD. The ADAHRS source selection switch
on the instrument panel must be toggled by the pilot to the right-
hand PFD.
For dual Avidyne PFD equipped aircraft that also are equipped
with a Pilot Priority switch on the instrument panel as described in
the Avidyne PFD Pilot Guide, selecting the Uncoupled option will
have no affect on the DFC90.
A PFD-to-PFD Miscompare will have no affect on the DFC90 in
dual-Avidyne PFD equipped aircraft. In these aircraft, the DFC90
is still using the AHRS-Turn Coordinator comparator and not the
PFD-PFD comparator.
If manually transitioning from an Altitude Capture to Altitude Hold
mode in dual-PFD equipped aircraft, it may be necessary to press
the ALT button on the DFC90 control panel a second time in pre-
Release 8.0.6 systems.
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