BendixKing KFC 500 User Manual
Page 17
16
ALT SEL (automatic capture of
selected altitude)
“ALT” is annunciated in white on
the EADI when the Altitude Select
mode is armed by depressing the
SEL pushbutton on the KAV 485
Altimeter/Vertical Speed Indicator.
The selected altitude is displayed in
the KAV 485’s altitude preselect win-
dow. Altitude Select will automati-
cally Arm after a change in the alti-
tude select value. The Altitude
Select mode provides a method for
selecting, capturing, and tracking
another altitude. ALT SEL requires a
compatible vertical mode to be used
to acquire the selected altitude.
Upon reaching the altitude capture
point, the selected vertical mode will
cancel and the flight director will
engage Altitude Capture and then
Altitude Hold. Altitude Select must be
deactivated to inhibit capture and
tracking of the preselected altitude.
If the value of selected altitude is
changed while in altitude capture, the
system reverts to pitch attitude hold
mode. In the event of sustained
invalid altitude, ALT SEL mode will
deactivate. To disengage Altitude
Select, press the SEL mode push-
button on the KAV 485. Detailed
operation of the KAV 485 is
described on page 34.
ALT HOLD (hold current reference
altitude)
The light above the ALT pushbut-
ton illuminates and “ALT” is dis-
played on the EADI in green when
the Altitude Hold mode is activated
by depressing the ALT pushbutton or
by automatic sequencing through
Altitude Arm and Altitude Capture.
In the Altitude Hold mode, the flight
director commands pitch attitudes for
tracking of the helicopter altitude at
the moment of mode selection. The
system normally uses barometrically
corrected altitude, but can use pres-
sure altitude in the event barometric
altitude is not available. Altitude Hold
can be entered directly or in conjunc-
tion with the Altitude Select mode.
Engaging Altitude Hold directly dur-
ing a climb or descent will cause the
aircraft to fly through the desired alti-
tude and then return to the desired
altitude from the other side. For this
reason, the vertical speed should be
limited to 500 fpm when this method
KMS 540 Vertical Mode Selection
0
2
3
4
5
6
7
8
9
ALT
1,160
30.08 1,700
1
ı
ALT
ALERT
ALT
SEL
SEL
U
P LL
V S
KAV 485 Altitude Select
ALT
☛
Selected
Altitude
Display