(c)  
Remove the accelerometer.

 TASK 22-21-03-404-026
 3.  Modal Suppression Accelerometer Installation (Fig. 401)____________________________________________
 A. References
 (1)  
22-21-00/501, Yaw Damper System

 (2)  
24-22-00/201, Manual Control

 (3)  
29-11-00/201, Main Hydraulic Supply System

 (4)  
34-21-00/201, Inertial Reference System

 (5)  
53-21-02/401, Main and Upper Deck Floor

 (6)  
IPC 22-21-03, Fig. 1

 B. Access
 (1)  Location Zone 115 Area between Nose Gear Well and Fuselage, LH 116 Area between Nose Gear Well and Fuselage, RH 145 Bulk Cargo Compartment, LH 146 Bulk Cargo Compartment, RH
 C. Procedure
 S 424-027
 (1)  Do these steps to install the accelerometer:
 (a)  Put the modal suppression accelerometer in its position.
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747-400 MAINTENANCE MANUAL
 (b)  
Make sure the arrow on the accelerometer points to the right side.

 (c)  
Install the washers and mounting bolts on the accelerometer.

 (d)  
Connect the electrical connector to the accelerometer.

 D. Modal Suppression Accelerometer Test
 S 864-045
 (1) Close these circuit breakers and remove the DO-NOT-CLOSE tags:
 (a)  P7 Overhead Circuit Breaker Panel
 1) 7C10 FLT CONT ELEC 2L AC
 2) 7C12 FLT CONT ELEC 1L AC
 3) 7C14 FLT CONT ELEC 1R AC
 4) 7C16 FLT CONT ELEC 2R AC

 S 864-028
 (2)  
Supply the electrical power (Ref 24-22-00/201).

 S 864-034

 (3)  
Align the left, center and right IRUs in the NAV mode
 (AMM 34-21-00/201).

 S 864-035
 WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF ALL CONTROL
_______ SURFACES BEFORE YOU SUPPLY HYDRAULIC POWER. AILERONS, RUDDERS, ELEVATORS, FLAPS, SLATS, SPOILERS, LANDING GEAR, AND THRUST REVERSERS CAN MOVE QUICKLY WHEN YOU SUPPLY HYDRAULIC POWER. THIS CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.
 (4)  
Supply the hydraulic pressure to the hydraulic systems No. 2 and No. 3 (Ref 29-11-00/201).

 S 864-046

 (5)  
Make sure the FLT CONTROL HYD POWER TAIL 2 and 3 switches are in the NORM position. These switches are on the Pilots' Overhead Maintenance Panel (P461).

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 S 864-037
 (6)  
Push and release the engage switch of the applicable yaw damper (P5) to engage the yaw damper system. Make sure that the ON annunciator comes on and the INOP annunciator is off.

 S 744-039

 (7)  
Do this task: Ground Test - Yaw Damper (Ref 22-21-00/501).

 NOTE: The right aft and forward modal suppression accelerometers
____ are connected to the lower yaw damper module. The left aft and forward modal suppression accelerometers are connected to the upper yaw damper module.
 E. Airplane to Its Initial Condition
 S 864-040
 (1)  
Push and release the engage switch of the applicable yaw damper (P5) to disengage the yaw damper system.

 S 864-041

 (2)  
Set all the mode selector switches on the IRS control panel (P5) to the OFF position if it is not necessary (Ref 34-21-00/201).

 S 414-042

 (3)  
Install the applicable panel in the main deck floor
 (Ref 53-21-02/401).

 S 864-043

 (4)  
Remove the hydraulic power if it is not necessary
 (Ref 29-11-00/201).

 S 864-044

 (5)  
　
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