BendixKing KFC 500 - Manual (Page 21)

Normal Operation
32 June 15, 1999 006-08769-0000
Normal Operation
33 006-08769-0000 June 15, 1999
Indicated Airspeed Hold
The lamp above the IAS push-button
illuminates when the airspeed hold
mode is activated by depressing the
IAS push-button on the mode select
panel. Engaging the Indicated
Airspeed Hold mode causes the
flight director to command pitch atti-
tudes to maintain the indicated air-
speed current upon selection. The
airspeed displayed on the pilot’s or
copilot’s airspeed indicator may not
exactly agree with the value being
used by the AFCS. The airspeed ref-
erence is provided by the KDC 481T
central air data computer.
The commanded indicated airspeed
reference value is displayed on the
EADI. This value may be modified by
moving the CBT switch forward
(increase reference airspeed) or
rearward (decrease reference air-
speed).
The pilot may also press the FTR
switch and manually fly the aircraft to
a new airspeed. The AFCS will hold
the new airspeed reference existing
at the time of release of the FTR
switch.
Continuous flashing of the annuncia-
tor lamp above the push-button and
the flashing of and changing color
from green to yellow of the IAS
annunciation on the EADI indicates
loss of a valid air speed signal from
the air data computer. Flashing con-
tinues until the IAS push-button on
the mode selector is pushed and
released (pilot acknowledgment or
mode loss) or another vertical mode
is selected. The IAS push-button
may be used to deactivate the IAS
mode at any time. Upon manual
deactivation, the annunciator lamp
above the IAS push-button and the
green IAS annunciation on the EADI
will flash for five seconds. This flash
sequence will terminate upon reacti-
vation of IAS or another pitch mode.
Overspeed Protection
As a safety feature, the flight director
automatically reverts to Indicated
Airspeed Hold and flashes the IAS
annunciation (amber “IAS” on EADI)
whenever the helicopter exceeds
VNE or the rate of closure with VNE
is excessive. The flight director will
command pitch attitudes to reduce
indicated airspeed to VNE and then
resume the previous pitch mode.
Overspeed protection is not provided
in Altitude Hold or Altitude Capture
Modes.
Vertical Speed Hold (VS)
Depressing the ENG push-button on
the KAV 485 Altimeter/Vertical
Speed Indicator or the VS button on
the KMS 540 Mode Select Panel
activates the vertical speed hold
mode. In vertical speed mode the
system commands pitch attitudes to
maintain the vertical speed present
at the time of engagement.
The reference vertical speed being
flown is displayed on the EADI in the
AFCS annunciation field and by the
vertical speed bug on the KAV 485
Altitude/Vertical Speed Indicator.
This vertical speed may be modified
by using the CBT switch. Pushing
the CBT switch forward slews the
existing vertical speed reference
towards zero or negative, and push-
ing aft slews the value towards zero
or positive.
The pilot may also press the FTR
switch and manually fly the aircraft to
a new vertical speed. The AFCS will
hold the new vertical speed refer-
ence existing at the time of release
of the FTR switch.
A vertical speed may be pre-
selected via the KAV 485
Altimeter/Vertical Speed Indicator.
Pull out on the vertical speed select
(SEL) knob to reposition the vertical
speed bug and/or bring the bug into
view if vertical speed mode is not
already engaged. Rotate the small
knob to make 100 fpm per click and
the large knob to make 1000 fpm per
click changes to the vertical speed. If
a vertical speed is already pre-
selected at the time of vertical speed
mode engagement, the pre-selected
value will be used immediately by
the AFCS without further action by
the pilot. If the mode is not already
engaged press the ENG push-button
on the altimeter/vertical speed indi-
cator to engage the mode. Push the
select (SEL) knob back in after the
bug position has been modified.
Note: When the select (SEL) knob
is pulled out the knobs modify the
position of the vertical speed bug.
When the knob is pushed in the
knobs modify the selected alti-
tude shown in a digital window on
the indicator.
Continuous flashing of the annunci-
ator lamp above the push-button and
the flashing of and changing color
from green to yellow of the VS
annunciation on the EADI indicates
loss of a valid vertical speed signal
from the air data computer or loss of
valid vertical acceleration from the
KRG 333 Rate/Acceleration Sensor.
Flashing continues until the VS
push-button on the mode select
panel is pushed or another pitch
mode is selected (pilot acknowledg-
ment of mode loss). The VS push-
button may be used to deactivate
the VS mode at any time. Upon
manual deactivation, the annunciator
lamp above the VS push-button and
the green VS annunciation on the
EADI will flash for five seconds. This
flash sequence will terminate upon
reactivation of VS or another pitch
mode.
KAV 485 Vertical Speed
Select
VS
☛
VS ALT
1000 FT/MIN
VS
2
3
2 1
1
.5
.5
0
UP
DN
IN HG HPa DEN ALT
SEL
VS
. ,
ENG SEL
BARO
U P SH
E
T
S T
SEL
U P LL
V S
3
Vertical Speed Bug
IAS
☛