BendixKing KFC 500 - Manual (Page 15)

Yaw Force Trim Release
A collective mounted Yaw Force
Trim Release is provided. If the
Force Trim System is on, depressing
this switch releases the yaw clutch
(AFCS yaw axis will revert to SCAS
if engaged), allowing free anti-torque
pedal movement. In flight director
equipped aircraft, if the autopilot is
engaged, upon release of the switch
the autopilot will command ball cen-
tered flight.
Normal Operation
20 June 15, 1999 006-08769-0000
Normal Operation
21 006-08769-0000 June 15, 1999
Flight Director Operation
Modes of Operation
The KMS 540 Mode Select Panel
provides control and annunciation of
the KFC 500’s Flight Director modes
as well as the Autopilot and SCAS
modes. The Autopilot and SCAS
modes operate the same as previ-
ously described in the
SCAS/Autopilot section. To activate
flight director modes using the Mode
Select Panel, press and release the
desired button. The corresponding
mode lamp above the push-button
will illuminate and the mode annunci-
The following section provides an explanation of the normal operating proce-
dures for the flight director functions of the KFC 500 SCAS/AP System when
equipped with Flight Director. SCAS/AP operation is identical to that of the
basic SCAS/AP System, described in the proceeding section, with the follow-
ing exceptions.
SCAS/AP Operation
(Flight Director installed)
When the Flight Director is included
in the system a central air data sys-
tem is also installed. The air data
system allows the AFCS to provide
additional functionality in the yaw
axis plus improved performance with
airspeed gain scheduling. The yaw
axis, as described in the previous
section, augments rotorcraft stability
by opposing uncommanded yaw
motion (rate damping - keeps nose
from moving) and ball centering.
With an air data system installed,
the yaw axis also provides turn coor-
dination and yaw trim (using lateral
acceleration). Lateral acceleration is
used by the system to provide the
described functionality anytime that
the acceleration sensor is valid, the
AFCS is receiving valid airspeed
information from the air data, and the
aircraft is flying at an indicated air-
speed greater than 50 knots. When
the aircraft is flying below 50 KIAS,
lateral acceleration is inhibited.
During this time the AFCS yaw axis
will provide yaw rate damping only.
ı
APR HDG
ALT
BL
IAS
AP FD
NAV
VS
SCAS
KMS 540 Flight Director Mode Select Panel
ation on the Electronic Attitude
Indicator (EADI) will appear.
Alternatively, to deactivate a flight
director mode when activated,
depress and release the respective
push-button. The illumination level of
the annunciator lamps on the mode
selector is adjusted automatically by
a photocell located on the face of the
unit. The button nomenclature back
lighting is controlled by the pedestal
dimmer control on the overhead
panel.
AFCS
GROUND
TEST
SCAS &
AP PWR
OFF
EFIS PWR
PL1
OFF
EFIS PWR
CPL1
OFF
YAW
FORCE
TRIM
RELEASE