BendixKing KFC 500 - Manual (Page 22)

Normal Operation
34 June 15, 1999 006-08769-0000
Normal Operation
35 006-08769-0000 June 15, 1999
KSA 572 Trim Actuator
The KFC 500 incorporates three trim
actuators (one per axis) in parallel
with the helicopter control linkage.
The trim actuators provide the long-
term control guidance by moving the
control system to allow the linear
actuators to center and thus main-
tain control authority. The trim servo
also houses the magnetic brake por-
tion of the force trim system. The
force trim system also contains a
spring cartridge assembly, in each
axis, which houses a spring and a
sense switch. The spring provides
positive feedback to the pilot or copi-
lot proportional to the amount of con-
trol movement. When the pilot or
copilot moves the cyclic or antitorque
pedals the detent (sense) switch will
be activated. If the AP mode is
engaged and the detent switch is
activated the trim actuator drive is
interrupted. If the pilot or copilot
moves the cyclic (pitch and/or roll)
through the detent/s the AFCS will
revert automatically to SCAS (SCAS
annunciator lit). If the pilot or copliot
moves the anti-torque pedals
through the detent the yaw axis will
revert to SCAS operation, but the
pitch and roll axes will remain in AP
mode (SCAS annunciated on Mode
Select Panel and on discrete annun-
ciator). The pilot or copilot may man-
ually fly the aircraft at any time using
this method (Pilot Fly-Through
Mode). Once the pilot or copilot is
ready to allow the autopilot to take
over, the force trim switch may be
pushed and the cyclic and anti-
torque pedals (if applicable) posi-
tioned as desired or release the stick
and pedals and allow the autopilot to
return to its original reference. At
activation of the FTR switch, the
cyclic and the pedals the spring car-
tridge detent switches will release.
The SCAS mode will automatically
disengage (SCAS annunciator out)
and the AP mode will re-engage (AP
annunciator on). The AFCS will
return to the appropriate reference
for the mode engaged. The AFCS is
designed with absolute attitude limits
and rate limits. During fly through or
other modes of operation , the air-
craft attitude/rate must be less than
+ or - 45°/15° per second in roll and
+ or - 15°/10° per second in pitch
and 15° per second in yaw for the
AP mode to remain engaged. If
these limits are exceeded the autopi-
lot will automatically disconnect.
Force Trim and AP Trim
KSM 575 Linear Actuator
Assembly
A KSM 575 Linear Actuator is
installed in pitch, roll and yaw (anti-
torque) axis of helicopter. The linear
actuator is placed in series with the
control rods to provide limited
authority high speed damping of the
helicopter. The linear actuator con-
tains a position transducer for feed-
back of actuator position to the Flight
Computer.
KCP 520 Flight Computer
The KCP 520 Flight Computer pro-
vides all of the command computa-
tion for SCAS, autopilot and flight
director. The KCP 520 houses four
microprocessors. Two (redundant)
Autopilot processors provide the
autopilot control computations and
autopilot/stability augmentation
mode logic, a dedicated processor
for Flight Director provides command
computation and a dedicated
Maintenance processor assists in
diagnostics and maintenance. Inputs
to the Flight Control Computer
include control position feedback
from the control position transduc-
ers, and Attitude, Directional, and
Rate information from the vertical,
directional and rate gyros and accel-
eration from the acceleration sen-
sors. The KCP 520 outputs servo
drive to move the linear and trim
actuators.
AFCS Sensors
KVG 350 Attitude Gyro
The KVG 350 Vertical Gyro provides
attitude information to the EFIS and
the KCP 520 Flight Computer. The
attitude information received by the
Flight Computer is used for computa-
tions and system monitoring.
KCS 305 Slaved Compass
System
The KCS 305 Slaved Compass
System is comprised of the KSG 105
Directional Gyro, the KA 51B
Slaving Accessory, and the KMT 112
Flux Valve. The slaved compass sys-
tem provides magnetic heading infor-
mation to the EFIS and the Flight
Computer.The Free/Slave switch
provides the pilot a means to manu-
ally compensate for magnetic effects
POSITION
SYNCHRO
CYCLIC
FORCE
GRADIENT
SPRING
DETENT
SWITCH
INSIDE
TO
LINEAR
ACTUATOR
TRIM SERVO/
MAG BRAKE
MAN
CW
AUTO
CCW
- +
KSG 105
1
KCP 520 ı
Flight Control System Components
(SCAS, Autopilot, and Flight Director)