12-15-04
ALL ú ú 02 Page 307 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
(f) Make sure the pressure differences are not more than the values in the table.
~...................................................... | LANDING GEAR | MAXIMUM PRESSURE DIFFERENCE (PSI) | ........................................................ | Wing gear | 150 | | Body gear | 150 | | All Main Gear | 400 | 2................….....................................1
1) If the airplane has all the conditions given above, permit the airplane to dispatch.
2) If the airplane does not have all the conditions given above after the first fast check, do these steps: a) Add or release pressure to the necessary shock struts
to get them to a point in the servicing band (Refer to
the applicable shock strut servicing placards).
NOTE: Do not permit a shock strut to have less than 1
____ inch (25.4mm) of extension (visible chrome), measured from the lower surface of the shock strut outer cylinder.
b) Do the fast check again for each landing gear.
3) If the airplane does not have all the conditions given above after the second fast check, add air to or release air from the struts to get them to a point in the servicing band (Refer to the applicable shock strut servicing placards).
NOTE: This step is to permit the dispatch of the
____ airplane for one flight to a station where the shock strut servicing equipments are available.
TASK 12-15-04-703-017
4. Body Landing Gear Pressure/Extension Check__________________________________________
A. General
(1) 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 shock strut is serviceable.
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12-15-04
ALL ú ú 02 Page 308 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
B. Access
(1) Location Zone
755 Body Landing Gear, LH
765 Body Landing Gear, RH
C. Procedure (Fig. 301)
S 863-018
(1) Make sure the airplane is empty.
NOTE: For this check, the landing weight of the airplane is
____
sufficient for the empty condition.
S 723-020
(2) Do a check of the landing gear pressurization with the airplane empty:
(a)
Measure the pressures and the extensions of the shock struts on the wing landing gear.
(b)
Compare the pressures and extensions to the band on the servicing chart.
(c)
Find the intersection of the pressure and dimension X on the servicing chart. 1) Add or release gas until the pressure and dimension X are
in the servicing band.
S 863-049
(3) Put 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.
S 723-031
(4) Do 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.
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12-15-04
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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747-400 MAINTENANCE MANUAL
(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.
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