RIGHTAILERON
RUD CONTROLCABLES
AIL ELEV AIL
EICAS DISPLAY STATUS PAGE
FIRST OFFICER'SPOWER CONTROL
CONTROL WHEEL ACTUATORS(2 EACH WING)
CAPTAIN'S
CONTROL
WHEEL

LEFTAILERON
COLUMN FORCE
TRANSDUCER 1

BUS ROD
WHEEL FORCE
TRANSDUCERS 1

AILERON TRIM
COLUMN FORCE

SWITCHES
TRANSDUCER

1
RIGHT BUS ROD
AILERON FIRST OFFICER'S
OVERRIDE MECHANISM
RIGHT AUTOPILOTLATERAL CONTROLSERVO (ALCS)
CENTER AND
LEFT ALCS

1AIRPLANES WITH CONTROL WHEEL STEERING
Aileron Control System
Figure 16

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MAINTENANCE MANUAL

 (2)  
Feel is provided by a moving cam with a spring loaded cam follower. The cam is on the aft quadrant shaft, which is rotated by cables to the control wheels. The follower is a roller referenced to structure through the trim actuator. Movement of the aft quadrant shaft and cam is resisted by the spring loaded cam follower. The cam causes the follower to stretch the spring, and provide a centering force.

 (3)  
The trim actuator changes the relative position of the cam follower, thereby changing the center position of the cam. The actuator is an electric motor with a jackscrew drive shaft. Trim centering occurs when the actuator moves the spring loaded cam follower causing the roller to ride up the sides of the cam. This increases tension on the spring and the cam. The quadrant and control wheels relieve this spring tension by centering the cam on the roller.

 S. Aileron Control System Operation
 (1)  
The aileron control system consists of interconnecting cables and pushrods. Control wheel movement is either by manual force, or is back-driven by an ALCS. Any one ALCS can drive the primary system through interconnects in the wheel well. Aerodynamic feel is artificially applied by the feel, trim, and centering mechanism, since hydraulic force overcomes aerodynamic forces.

 (2)  
Each aileron is powered by two PCAs. The PCAs are controlled by manual inputs or autopilot inputs from the FCCs through the ALCSs. Each PCA and ALCS uses power from one of three main hydraulic systems. The aileron position is detected by position transmitters on each aileron and is indicated on the lower EICAS display unit status page (Ref 31-41-00).

 (3)  
Three Rotary Variable Differential Transducers (RVDTs) are on each forward quadrant. Each RVDT senses control wheel movement and provides independent electrical signals to Spoiler Control Modules (SCMs). The signals are processed by the SCMs to command spoiler movement that augments roll control. The spoiler RVDT primary winding uses 26 vac from the CSEU power supplies.

 T. Spoiler Control System Operation (Fig. 17)
 (1)  Twelve spoilers are on the airplane wings. Spoilers one through six are on the left. Spoilers seven through twelve are on the right. Spoiler pick-up is at 10 degrees of control wheel rotation. Inputs from the RVDTs on the forward quadrants are proportional to control wheel movement. The inputs are processed by six spoiler control modules (SCMs).
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757
MAINTENANCE MANUAL

SPOILER DEFLECTION LEGEND
CNF 5000-M184INDICATOR
LIGHTS
31-41-XXLATERAL CONTROL45
FULL TRAVEL

MAXIMUM ANGLESPOILERS GROUNDSPEED BRAKE
30 45
M10182 R EICASFLIGHT SPEED BRAKE
MAX ANGLECOMPUTER (E4-2)MAXIMUM ANGLE
70
REF

31-41-XX
M10181 L EICASCOMPUTER (E4-2)
FROM TRANSDUCER (3 PLACES) TRUCK TILT
HYD PRESS
SENSOR
FROM TRANSDUCER (3 PLACES)
32-09-XX TO ACTUATOR
LEFT TRUCKPOSITIONTHRUST
AIR/SENSOR
GNDLEVER
32-09-XXRELAYSSWITCH
　
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