Altitude Hold commands may be
modified by holding the autopilot Ver-
tical Trim rocker switch in the up or
down position either momentarily or
for several seconds
at
a time. Momen-
tary switch activation modifies target
altitudes at the rate of
20
feet per
"click." Continuous Vertical Trim
operation causes the flight director to
command a climb or descent, as ap-
propriate, at
500
fpm until the switch
is released.
Altitude
Select
(ALT ARM)
The Altitude Select mode arms the
flight director for capture and tracking
of altitudes selected with the KAV
485
AltitudeNertical Speed Indicator or
KNS
660.
A
separate vertical mode,
must be engaged to provide flight
guidance to the point of altitude cap-
ture. Upon reaching the altitude cap-
ture point, the selected vertical mode
will cancel and the flight director will
engage Altitude Capture and then Alti-
tude Hold.
During transitions to armed alti-
tudes the KFC
400
briefly sounds an
alert tone when the aircraft passes
within
1000
feet of the selected alti-
tude. In addition, an Alert annunciator
illuminates on the KAV
485
when the
aircraft is between
1000
and
300
feet
above or below the armed altitude.
The annunciator illuminates again,
briefly, when the aircraft reaches the
selected altitude. Subsequently,
alerts are provided
if
the aircraft devi-
ates
300
feet or more from the se-
lected altitude. Strapping is also
available in some installations for alert
when the aircraft deviates more than
200
feet.
Altitude Select will engage auto-
matically with selection of Climb or
Descent modes, provided that a
higher or lower altitude, as appropri-
ate, is displayed in the KAV
485s
alti-
tude preselect window. Altitude Select
must
be
disengaged to inhibit capture
and tracking of the preselected alti-
tude.
To disengage Altitude Select,
press the appropriate mode selector
key on either the KMS
446
or
KAV
485.
Climb Mode (CLB)
At typical aircraft climb power set-
tings, selecting the Climb mode
causes the flight director to command
pitch attitudes to maintain a pro-
grammed climb that alters airspeed
with reference
to
altitude. The climb
profile conforms to a comfortable air-
craft attitude for use during en route
climbs. The exact climb profile is pro-
grammed for each aircraft type.
Engaging the Climb mode also
activates the Altitude Select mode
whenever a higher altitude is dis-
played in the KAV
485s
altitude pre-
select window. In that case, the flight
director automatically cancels the
Climb mode upon initiation of Altitude
Capture and transition to Altitude
Hold.
Selecting the Climb mode with
the aircraft operating at a reduced
power setting may cause the flight
director to command level flight until
the aircraft accelerates to the sched-
uled airspeed for the current altitude.
Only upon reaching that target air-
speed will the flight director command
pitch attitudes
to
initiate the climb.
Descent Mode (DESC)
In the Descent mode the flight di-
rector commands pitch attitudes to
initiate a descent at a predetermined
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