(a)
Air Data Computers (ADCs)
(b)
Inertial Reference Units (IRUs)
(c)
AIRPLANES WITH -122 YDM AND SUBSEQUENT YDM DASH NUMBERS; Modal Suppression Accelerometer
(2)
These commands drive the yaw damper servos, which control the rudder through power control actuators. The modules monitor system operation and indicate system faults through automatic and manually initiated system testing. Yaw damper fault indications consist of the following (Ref 31-41-00):
(a)
Yaw damper panel INOP light
(b)
EICAS display unit annunciation
(c)
AIRPLANES WITH YDM DASH NUMBERS -101 THRU -121; Module faultballs
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SEE E
SEE F
SEE A B C
SEE D ANNUNCIATION WARNING
TEST PANEL TEST SWITCH YAW DAMPER GND PROX WING AFT STALLL RCMPTR AIR DATA R L PROBE HEAT WINDOW/ ANTI ICE QTY FUEL LEAK DUCT FWD EQUIP COOL LDG INOP T/O CONFIG TEST L YAW DMPR R CONTROL PANEL YAW DAMPER ENGAGE SWITCHES YAW DAMPER RL YAW DAMPER a w INOP ON a INOP w ON EICAS DISPLAY R YAW DAMPER L YAW DAMPER EGI 327 97.5 1.28 1.65 1.0 1.4 1.8 327 97.5 1.28 1.65 N1 EPR CLB TAT - 12C
A B C
ACCELEROMETER SUPPRESSION MODAL
F 1
L AND R ADC
L,C, AND R IRU
L AND R YAW DAMPER MODULES LEFT AND RIGHT YAW DAMPER SERVO
1 FOR AIRPLANES WITH -122 D E
AND ON YAW DAMPER MODULE
Yaw Damper System
Figure 1
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(d) AIRPLANES WITH -122 YDM AND SUBSEQUENT YDM DASH NUMBERS;
Fault message displayYaw Damper Servos (2)
(1)
The yaw damper servos use electrical command inputs from the yaw damper modules. The electrical input commands control hydraulic flow to actuator pistons, which provide a mechanical output. This output is connected in series with manual and autopilot rudder inputs supplied to rudder power control actuators, which actually move the rudder.
(2)
The maximum rudder authority for each SERVO is 6 degrees (3 degrees in each direction). If both SERVOS are operating, the rudder authority is 12 degrees. The yaw damper servo command is zero while the airplane is on ground, except during preflight testing. The yaw damper command is provided to the servos via an easy-on/easy-off function that reduces transients during ground/air transitions. If a system fault is detected, the servos are disengaged.
AIRPLANES WITH -122 YDM AND SUBSEQUENT YDM DASH NUMBERS; Modal Suppression Accelerometer
(1)
The modal suppression accelerometers provide the yaw damper modules with lateral acceleration data. Each yaw damper module has its own modal suppression accelerometer.
Yaw Damper Component Locations (Fig. 2)
(1)
Flight Deck
(a) The pilots overhead panel (P5) contains the yaw damper controls and indicators. Each channel (left and right) has a separate yaw damper ON switch/light and INOP indicator. The YAW DMPR test switch is on the P61 panel.
(2)
Main Equipment Center
(a) The yaw damper modules are located in the main electrical/electronic equipment center. The right module is on the E4-1 shelf. The left module is on the E3-1 shelf. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：757 AMM 飞机维护手册 自动飞行 AUTOFLIGHT 2(21)
