System Overview
1-9
Similarly, Envelope Protection (EP
™) will provide high-speed
protection and alerting near V
ne
. In this case, as V
ne
is
approached in AP mode, the autopilot will adjust pitch as required
to maintain an airspeed near V
ne
. Aircraft bank angle is not
adjusted by the autopilot during overspeed protection. Depending
on conditions (e.g. rapidly changing airspeed, turbulence, etc.), it
is possible for V
ne
to be exceeded. An overspeed condition is
annunciated to the pilot via an “
OVERSPEED
” text alert on the
PFD, a “SPEED PROTECTION ACTIVE” aural alert in the
headsets, and by a flashing of any engaged (green) autopilot
mode annunciators.
The DFC90 is capable of taking flap position into account in
Envelope Protection (EP
™) and Envelope Alerting (EA™)
calculations and as a result, the definition of V
s
, changes
depending on flap position in those aircraft with the flap wiring
installed. The use of this flap input is part of Avidyne
’s Adaptive
Autopilot
™ concept.
NOTE
Envelope Protection During Icing Conditions
The DFC90 autopilot is not to be used during icing
conditions. The autopilot does not have any kind of
AOA or icing input and therefore does not register
changing aircraft dynamics during icing conditions.
Therefore, Envelope Protection (EP
™) is not
effective under icing conditions.
Change 3