AUTOMATIC FLIGHT CONTROL SYSTEM (AFCS)
COMPONENT
STABILATOR
SAS 1
SAS 2
TRIM
FPS
FUNCTION
MAINTAINS LEVEL
ATTITUDE IN FLIGHT.
ENHANCES HANDLING
QUALITIES AND
IMPROVES C. G. RANGE
PROVIDES SHORT-TERM
RATE DAMPENING FOR
DYNAMIC STABILITY
PROVIDES SHORT-TERM
RATE DAMPENING FOR
DYNAMIC STABILITY
PROVIDES A FORCE
GRADIENT
PROVIDES LONG-TERM
RATE DAMPENING IN
P/R/Y AXIS FOR STATIC
STABILITY
BRAINS
MUSCLE
TWO
STABILATOR
AMPLIFIERS
TWO STABILATOR
ACTUATORS
#1 DC ESS
#2 DC PRI
SAS AMPLIFIER
(ANALOG)
SAS AMPLIFIER
(DIGITAL)
INSIDE SAS
2/FPS
COMPUTER
MONITORED BY
SAS 2/FPS
COMPUTER
SAS 2/FPS
COMPUTER
%CONTROL
AXIS
N/A
N/A
PITCH, ROLL AND
YAW SAS
ACTUATORS
UP TO 5%
(10%
COUPLED
W/SAS 2)
PITCH
ROLL
YAW
PITCH, ROLL AND
YAW SAS
ACTUATORS
UP TO 5%
(10%
COUPLED
W/SAS 1)
PITCH
ROLL
YAW
3 TRIM
ACTUATORS
(2 ELEC/1HYD)
100% WHEN
COUPLED
WITH FPS
PITCH
ROLL
YAW
3 TRIM
ACTUATORS
(2 ELEC/1HYD)
100% WHEN
COUPLED
WITH TRIM
PITCH
ROLL
YAW
REMARKS
PROGRAMMED FOR FIVE
BASIC FUNCTIONS (SCALP)
STREAMLINES, COLLECTIVE
COUPLING, ANGLE OF
INCIDENCE, SIDESLIP-TOPITCH AND PITCH-RATE
FEEDBACK
SAS DOES NOT MOVE THE FLT
CONTROLS
(TO DOUBLE GAIN
MALFUNCTIONING SAS MUST BE
DISENGAGED)
ONE SAS UP TO 5%
SAS DOES NOT MOVE THE FLT
CONTROLS
(TO DOUBLE GAIN
MALFUNCTIONING SAS MUST BE
DISENGAGED)
ONE SAS UP TO 5%
PITCH TRIM SERVO IS HYDROMECHANICAL
ROLL AND YAW TRIM SERVOS
ARE ELECTRO-MECHANICAL
FOR FPS TO WORK
PROPERLY—MUST HAVE SAS 1
OR SAS 2 ON, TRIM, BOOST
AND STABILATOR
(TRIM WILL WORK W/OUT FPS BUT
FPS WON’T WORK W/OUT TRIM)
FPS PROVIDES CERTAIN FUNCTIONS AT AIRSPEEDS ABOVE AND
BELOW 60 KIAS
BELOW 60 KIAS
AXIS
ATTITUDE HOLD
PITCH
ABOVE 60 KIAS
ATTITUDE HOLD
AIRSPEED HOLD
ATTITUDE HOLD
ROLL
ATTITUDE HOLD
HEADING HOLD
YAW
HEADING HOLD
TURN COORDINATION*
(REQUIRES ½ “ CYCLIC AND 1 ½ DEG ROLL CHANGE)
AFCS CONSISTS OF 4 SUBSYSTEMS (SFTS):
• SAS 1 OR SAS 2
• FPS
• TRIM
• STABILATOR
FPS CONSISTS OF 4 SUBSYSTEMS (SBTS):
• SAS 1 OR SAS 2
• BOOST
• TRIM
• STABILATOR IN AUTO MODE (ENHANCES OPERATION BUT NOT REQUIRED)