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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 747-400 MAINTENANCE MANUAL
 (7)  S 863-038Put a load on the airplane.
 NOTE:____ For the best precision, the full weight of the airplane must be 200,000 pounds more than the empty weight of the airplane. The temperature difference between the times you measure the data must not be more than 20°F.
 (8)  S 723-039Do a check of the landing gear pressurization with a full load of weight and fuel in the airplane. (a) Measure the pressures and extensions of the shock struts for each body landing gear. (b) Compare the pressures and the extensions to the band on the servicing chart.
 NOTE:____ If the point is on the servicing band, then the fluid level is correct. If the point is on the right of the band, then the fluid level is too high. If the point is on the left of the band, then the fluid level is too low.
 (9)  S 613-040Perform a full servicing (Ref. "Body Landing Gear Shock Strut Servicing" task) or add hydraulic fluid to the full level (Ref. "Pressure/Extension Check" task) if the fluid level is not correct.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 12-15-04
 ALL  ú ú 02 Page 314 ú Feb 10/96
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 NOSE LANDING GEAR SHOCK STRUT - SERVICING
_________________________________________
 1.  General_______
 A.  This procedure contains 3 tasks:
 (1)  
A full servicing procedure

 (2)  
An optional procedure to use if you cannot lower the airplane.

 (3)  
A task to measure the fluid level in the shock strut without the removal of the fluid (pressure/extension check).

 B.  There is no easy procedure to do a check of the fluid level in the shock strut. The volume of the fluid changes when you pressurize the strut with nitrogen or dry air. You must do the full servicing procedure to accurately fill the shock strut.
 C.  AIRPLANES WITH A PRESSURE GAGE ON THE SHOCK STRUT; The vendor bends the indicator on the gage during calibration. A gage with a bent indicator is usually not a broken gage.
 D.  You can do a check of the fluid in the shock strut without the removal of fluid from the strut. The pressure and the extension of the shock strut at different airplane weights gives an indication of the fluid level. You must use the servicing chart to see if the strut is serviceable.
 TASK 12-15-05-603-001
 2.  Nose Landing Gear Shock Strut Servicing_______________________________________
 A.  General
 (1)  
This task gives the instructions to fill and pressurize the shock strut for the nose landing gear. On the airplane the shock strut nameplate and the servicing placard show the data which is also in this task.

 (2)  
Each shock strut contains approximately 8.0 gallons of hydraulic fluid. When the shock strut is full of fluid, you will pressurize it with nitrogen or dry air.

 (3)  
AIRPLANES WITHOUT A PRESSURE GAGE ON THE SHOCK STRUT; The air valve is on the pressure sensor assembly. The pressure sensor assembly is part of the green band system and is on the top of the shock strut.

 (4)  
AIRPLANES WITH A PRESSURE GAGE ON THE SHOCK STRUT; The air valve is on the pressure gage assembly. From the pressure gage, a line connects the air valve to the pressure sensor assembly.

 (5)  
You must add a lubricant to the shock strut during the servicing. As an alternative, you can use a fluid which has an added lubricant. For usual servicing when small quantities of fluid are necessary, you can use fluid without lubricant to fill the shock strut.

 B.  Special Tools and Equipment
 (1)  
F70200-14 - Strut Inflation Tool

 (2)  
3MIT65B00163-1 - Landing Gear Strut Service Manifold Assembly

 C.  Standard Tools and Equipment
 (1) Clean, nitrogen or dry air source - 1800 psi with pressure gages
　
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