BendixKing KFC 500 - Manual (Page 18)

17
of Attitude Hold engagement is used.
Selecting Altitude Hold after the
Altitude Select mode has been
engaged cancels Altitude Select
(white “ALT” on EADI). The flight
director will command the aircraft to
hold the altitude present at the
moment of mode selection.
Altitude Hold commands may be
modified by moving the CBT switch
forward (decrease reference altitude)
or rearward (increase reference alti-
tude).
A flashing lamp above the ALT
pushbutton indicates loss of a sensor
required to hold current reference
altitude (e.g. invalid altitude). The
flashing continues until a push of
the ALT pushbutton acknowledges
automatic deactivation of the mode.
The ALT pushbutton may also be
used to deactivate the altitude hold
mode.
IAS (hold current reference air-
speed)
The lamp above the IAS pushbutton
illuminates when the airspeed hold
mode is activated by depressing the
IAS pushbutton. Engaging the
Indicated Airspeed Hold Mode
causes the flight director to com-
mand pitch attitudes to maintain the
indicated airspeed current upon
selection. Airspeed commands may
be altered through use of the flight
director CBT switch.
OVERSPEED PROTECTION
A flashing IAS lamp indicates
loss of a sensor required to hold the
current reference airspeed (e.g.
invalid indicated airspeed). Flashing
continues until a second push of the
IAS pushbutton (pilot acknowledge-
ment of mode loss). The IAS push-
button may also be used to deacti-
vate the IAS hold mode. The
airspeed reference is provided by the
KDC 481T central air data computer.
As a safety feature, the flight
director automatically reverts to
Indicated Airspeed Hold and flashes
the IAS annunciator lamp (amber
“IAS” on EADI) whenever the heli-
copter exceeds a stored maximum
speed. Except in Altitude Hold and
altitude capture modes, the flight
director will command pitch attitudes
to reduce indicated airspeed to VNE
and then resume the previous pitch
mode.
VS (hold current or selected vertical
speed)
Depressing the ENG pushbutton on
the KAV 485 Altimeter/Vertical
Speed Indicator or on the KMS 540
Mode Select Panel activates the
flight director in Vertical Speed
mode. In Vertical Speed mode, the
flight director commands pitch atti-
tudes to maintain the vertical speed
selection displayed by the KAV 485
Altitude/Vertical Speed Indicator. In
IAS
☛
VS
☛