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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 S 865-121
 WARNING: YOU MUST CAREFULLY INSTALL THE GROUND LOCKS IN ALL LANDING
_______ GEAR. AN ACCIDENTAL RETRACTION OF THE LANDING GEAR CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.
 (1)  
Install the ground locks in all landing gear (AMM 09-11-00/201).

 S 865-033

 (2)  
Make sure that the landing gear control handle is in the Gear Down position.

 S 865-144

 (3)  
Pressurize hydraulic system No. 1 (AMM 29-11-00/201).

 S 875-143

 (4)  
Bleed the nose gear steering hydraulic system (AMM 29-11-00/201).

 (a)  
Operate the nose gear thru 5 full cycles.

 S 865-035
 (5)  
Release the pressure from hydraulic system No. 1 (AMM 29-11-00/201).

 S 865-036

 (6)  
Make sure that the rudder system is correctly rigged (AMM 27-21-00/501).

 S 865-037

 (7)  
On the P461 Pilot's Overhead Maintenance Panel, put the FLT CONTROL HYD POWER - TAIL VALVE switches No. 1, 2, 3, and 4 in the SHUTOFF position.

 S 865-038
 CAUTION: FAILURE TO OPEN THE CIRCUIT BREAKER BEFORE PERFORMING THE
_______ FOLLOWING PROCEDURES CAN RESULT IN DAMAGE TO EQUIPMENT OR EXCESSIVE EQUIPMENT OPERATING TIME.
 (8)  
Open the following circuit breakers:

 (a)  
P7 Overhead Circuit Breaker Panel
 1) 7G23 BODY GR STRG ARM AC
 2) 7G24 BODY GR STRG ARM DC

 (b)  
P180 DC Power Distribution Panel
 1) 180E7 ELEV/RUD VLV SYS 2
 2) 180H8 ELEV/RUD VLV SYS 1
 3) 180E22 ELEV/RUD VLV SYS 4
 4) 180E23 ELEV/RUD VLV SYS 3

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 015-039
 CAUTION: RESTRAIN THE TORSION LINK FROM DROPPING OR DAMAGE TO THE
_______
 SQUAT SWITCH MOUNTING BRACKET MAY RESULT.

 (9)  
Remove the nose gear torsion link apex bolt (Fig. 503).

 (a)  
Press the button and pull out the quick-release pin from the apex bolt.

 (b)  
Unscrew the apex bolt from the threaded bushing and pull it out.

 S 035-040
 (10)
 Manually move the upper link (restrained) through its arc to establish that an adequate clearance exists between the link and the P37 panel or the runway turnoff light housing.

 S 495-124

 (11)
 Secure the link to clear the nose wheel tires, using the torsion link holding tool.

 S 865-041

 (12)
 Make sure that the index mark on the steering collar bushing is aligned at zero on the nose gear protractor decal.

 S 865-042

 (13)
 Make sure that rig pin R-3 fits loosely in the rudder quadrant under the flight deck floor.

 S 085-134

 (14)
 Remove the tow safety pin, if it is installed.

 H.  
Test System Clearance, Valve Freedom and Centering

 S 715-043
 (1)  
Do a check of the steering system by manually bottoming out the steering actuator.

 (a)  
Manually turn the nose gear steering collar to the left (CCW) until the steering actuator bottoms out. 1) Make sure that the collar angular displacement is 70

 (+2/-3) degrees.
 2)  Make sure that that all the cables, pulleys, quadrants, tillers, rudder pedal steering system, summing mechanism and steering actuators are displaced freely, with no evidence of binding or galling or turnbuckle interference, throughout the system.
 S 715-044
 (2)  Repeat the above check but manually turn the nose gear steering collar to the right (CW) and check for the same result.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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