Page 21 D633W101-BEJ Sep 05/2002
AILERON AND FLAPERON CONTROL -WHEEL JAM BREAKOUT MECHANISM
Functional Description -Failure Mode
The wheel jam breakout mechanism permits the pilot to continue roll command if either wheel jams or a connection breaks.
If a right control wheel jams, the captain can operate the left wheel after overriding the 50 lb (23 kg) force of the breakout mechanism and the force of the feel and centering mechanism.
If the left control wheel jams, the first officer can operate the right control wheel after overriding only the force of the breakout mechanism. The right lost motion device engages after 2.9 degrees of control wheel movement. The lost motion device then turns the right shaft assembly.
If a control cable breaks between the control wheel and the cable drum, the pilot operates the other control wheel to control roll.
If a connection with the force transducer breaks, control roll through the motion device on the right cable drum. The right lost motion device engages after 2.9 degrees of control wheel movement.
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D633W101-BEJ Sep 05/2002
AILERON AND FLAPERON CONTROL -WHEEL JAM BREAKOUT MECHANISM
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D633W101-BEJ Jan 05/2002
AILERON AND FLAPERON CONTROL -WHEEL DAMPER
Purpose
The wheel damper absorbs control wheel vibrations and brings the wheel control system to rest with minimum oscillation.
Physical Description
The wheel damper is an LRU and weighs approximately 1.6 lb
(0.7 kg).
The wheel damper is the same as the pedal damper and the two column dampers. There are four of these dampers on the airplane.
The wheel damper is on the structure of the left shaft assembly mechanism. A damper crank and a control rod connect the damper shaft to the left crank. The control rod is not adjustable.
The wheel damper has an input shaft. The wheel damper uses a fluid to absorb vibrations that go to the shaft. A window on the wheel damper shows the position of the fluid level indicator.
The damper crank, on the damper shaft, has a pair of rivets. These shear out in case of a jam of the wheel damper.
Location
The wheel damper is on the mechanism of the left shaft assembly, between the flight deck floor and the left side of the nose gear wheel well. Access is through the MEC, then along the left side of the nose gear wheel well.
Functional Description
As the left shaft assembly turns, it turns the shaft of the wheel damper which absorbs the vibration of the wheel control system. The wheel damper adds a small force to the wheel control system.
Training Information Point
Put a pin through the inspection hole in the damper crank to check the rivet condition.
If the fluid level indicator shows a green band width of 1/16 inch or less, the fluid level is low. Then it is necessary to replace the wheel damper.
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AILERON AND FLAPERON CONTROL -WHEEL DAMPER
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D633W101-BEJ Jan 05/2002
AILERON AND FLAPERON CONTROL -AILERON FEEL AND CENTERING MECHANISM
Purpose
The aileron feel and centering mechanism supplies feel and centering forces to the aileron and flaperon control system. The aileron trim actuator supplies aileron trim control. The aileron trim moves the neutral position of the ailerons, the flaperons and the control wheels.
Physical Description
The aileron feel and centering mechanism consists of a single cam and roller unit. The cam attaches by a spline to the left shaft assembly and turns with it. The follower assembly has a roller which rolls on the cam surface. Two cranks hold the follower assembly. The cranks are bearing mounted on the left shaft assembly. A fitting attaches the two cranks together and to the trim actuator rod end. Two extension springs, between the fitting and the follower assembly, keep the roller on the cam.
The aileron trim actuator is a line replaceable unit (LRU). It is a 28v dc electrical, fixed rate motor which moves a non-reversible acme screw. The actuator attaches to the structure. The rod end of the actuator connects to the fitting of the feel and centering assembly.
Location
The aileron feel and centering mechanism is at the bottom of the left shaft assembly, between the flight deck floor and the nose gear wheel well. Access is through the MEC, then along the left side of the nose gear wheel well.
Functional Description
As the left shaft assembly and cam turn, the cam follower moves, which extends the two extension springs. The springs supply a feel force to the control wheels. The feel force varies from 5 lb (2 kg) to a maximum of 14 lb (6 kg) at 65 degrees of control wheel travel.
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