(3)
Mechanical feel is then accomplished with a cam and spring-loaded cam follower on the first officer's control crank working against the feel actuator. A cam detent also creates a centering force to keep elevators in the neutral (faired) position.
(4)
Total elevator feel force is the combination of mechanical and hydraulic force from the feel unit, plus system friction. Feel force returns the controls to neutral and resists their displacement from neutral.
Y. Stabilizer Trim System (Fig. 20)
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MAINTENANCE MANUAL
MANUAL ELECTRIC
TRIM SWITCHES
STABILIZERTRIMSEE A CONTROLMODULES
(2) MANUAL
TRIM
INPUT HYDRAULIC
RELEASED
BRAKE (2)
MANUAL ELECTRIC
TRIM SWITCHES
COLUMN CUTOUT SWITCHES
A
FLIGHTSTABILIZER TRIM
HYDRAULIC
HYDRAULIC
CONTROLAND ELEVATOR
TRIM CONTROL
RELEASED
MOTOR (2)
COMPUTERASYMMETRYARM BRAKELIMIT SWITCH
)
(L
)
(L
STCM
AND POSITIONBALLSCREWTRANSMITTER
)(L
HYDRAULIC
COLUMNACTUATORMODULES
MOTOR
CUTOUTASSEMBLY
SWITCHESFLIGHT
LIMIT SWITCH
BALLSCREW
AND POSITIONCOMPUTER
AIR/GNDFLAP/SLATADC
CONTROL
ACTUATOR
TRANSMITTER
LOGIC ELECT (3) (2)
ASSEMBLY
MODULE
)(C
HYDRAULICMOTOR
STAB TRIMSTCM
STABILIZER TRIM(R)
FLIGHT
APL
AND ELEVATORCONTROL
HYDRAULIC
CONTROL
NOSE
ASYMMETRY
RELEASED
0
ARM
COMPUTER
DN
MODULEBRAKE
(R)
2
(R)
S COLUMN
T 4
A SWITCHES
CUTOUT
6
B
STABILIZER 8
T
MANUAL TRIM
R
10 I
LEVERS
12
M
MANUAL TRIM
O
14 LIMIT SWITCH
LEVERS
FAND POSITION
APL F
NOSE
STAB TRIM
UP
TRANSMITTERINDICATORMODULE (3)
Stabilizer Trim System ComponentsSTABILIZER COMPARTMENT
Figure 20
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MAINTENANCE MANUAL
(1)
The stabilizer consists of two outboard control surfaces joined together with a center section to form one assembly. The stabilizer pivots about a point at the aft end of the center section. The leading edge of the center section is moved by a ballscrew actuator assembly. The actuator is controlled by two stabilizer trim control modules.
(2)
The stabilizer trim control modules respond to either mechanical or electrical inputs. Manual stabilizer trim levers drive cables which move ARM and CONTROL hydraulic valves on both stabilizer trim control modules. The left cables provide ARM inputs. The right cables provide CONTROL inputs. Electrical inputs from the SAM control solenoid operate ARM and CONTROL valves on each module.
(3)
Three limit switch and position transmitter modules are mounted on fixed structure below the center section leading edge. Switches and transmitters in the modules are positioned by control cables driven by the stabilizer. Each module includes a Rotary Linear Variable Transformer (RVDT), a synchro, and limit switches. The RVDT provides stabilizer position inputs to the Stabilizer Position Module (SPM). The synchro provides position signals for the stabilizer trim position indicator on the control stand.
(4)
Stabilizer trim faults are indicated by an amber STAB TRIM light on the P5 panel.
Z. Stabilizer Trim Control and Operation
(1) Stab Trim Control
(a) Four priorities of trim are available.
1) First priority trim control is manual via the trim levers and cables. The manual ARM input to the Stabilizer Trim Control Modules (STCM) inhibits all electrical inputs (Ref 27-41-00, Horizontal Stabilizer Trim Control System).
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