Abnormal Procedures
5-3
The following failure modes result in some degradation of the
DFC100 autopilot functionality as noted:
o
Loss of all on-board air data systems (results in the
inability to use any of the air data modes such as VS,
IAS, ALT modes, and loss of Envelope Protection and
Full-time Envelope Alerting functions - note that Straight
and Level, Pitch, Roll, and ILS capabilities are retained
and the VS knob can be used to adjust pitch)
o
Ice in the pitot-static lines (results in inability to track or
track accurately any IAS, VS, or ALT related mode)
o
Inoperative Mx and Safety Recorder (results in loss of all
aural alerting and autopilot disconnect tones)
o
Servo Failure (depending on the servo lost, potential
inability of the airplane to achieve set targets)
o
Servo Limit reached (results in the inability of the
autopilot to track the commanded targets)
o
Loss of Keyboard (forces the use of the
Bug Select
tab of
the PFD page to set Heading and Altitude bug targets)
o
Loss of both VHF radios (results in the inability to select
and track any VHF-based target such as Localizer, ILS or
VOR)
o
Loss of both GPS (results in inability to use FMS as the
source in Primary Nav LSK and therefore, no Vectors)
o
Crosscheck Attitude 1 (in single AHRS-equipped aircraft,
this specific Crosscheck Attitude message will result in an
autopilot disconnect and “Gyro Miscompare” aural alert
but it will allow a manual autopilot reengagement)
o
Gyro miscompare in the air (results in a disconnect of the
autopilot in dual AHRS equipped systems after a pitch or
roll miscompare and after any subsequent manual
reengagement, loss of comparator)
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