(2)
The primary function of tail support is to prevent the airplane tail from moving down if an aft CG condition occurs. The operator should develop procedures for the loading and unloading of cargo and fuel which will make tail support unnecessary. Tail support is recommended during cargo loading and unloading or fueling operations where CG movement procedures are not in place.
(3)
When you defuel or transfer fuel make sure all unnecessary support equipment and stands are away from the airplane. During the defuel or fuel transfer operation the change in fuel load causes the pitch and roll attitude to change. This condition can cause the wing or fuselage to move up or down. During windy or slippery conditions on the ramp, an aft CG condition can cause the airplane to weathervane and the nose of the airplane to move sideways. This movement can cause the airplane to contact support equipment.
D.
Lateral Fuel Imbalance
(1)
When it is necessary to defuel or transfer fuel unevenly between the left and right wings, obey the limits provided in the lateral fuel imbalance task.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
28-26-00
ALL ú ú 01 Page 201 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
E. Low Pressure Light Illumination During Defueling and Fuel Transfer
(1)
During the pressure defuel operation, the low pressure light for the override/jettison pumps can show. No maintenance action is necessary. The illumination of the low pressure light during ground defueling, fuel transfer or in-flight jettison is acceptable and expected because the pressure switch is installed to monitor engine feed performance.
F.
You must install safety locks on the leading edge or trailing edge flaps when persons do tasks near the flaps.
TASK 28-26-00-802-242
2. Pressure Defueling (Fig. 201)
__________________
A. General
(1)
Do this task to pressure defuel the airplane.
(2)
The fastest procedure for defueling is to connect the defueling hoses to all four fueling receptacles. You then operate the truck pumps and the airplane pumps at the same time. You can use this procedure to defuel the tanks fully if it is necessary. You can also use this procedure to remove only some of the fuel from the tank.
(3)
If you cannot supply electrical power to the airplane, you can defuel with the defueling pumps on the fuel truck. You can then drain the remaining fuel through the sump drain valves. If you must fully defuel the airplane, you must remove the fuel to the sump level with these pumps:
(a)
The fuel boost pumps
(b)
The override/jettison pumps
B.
References
(1)
AMM 12-11-01/301, Servicing - Fuel
(2)
AMM 07-11-08/201, Cargo and Fuel Loading Support
(3)
AMM 10-11-03/201, Parking (high wind)
(4)
AMM 20-41-01/201, Static Grounding
(5)
AMM 24-22-00/201, Manual Control
(6)
AMM 27-51-00/201, Trailing Edge Flap System
(7)
AMM 27-81-00/201, Leading Edge Flap System
(8)
AMM 28-15-00/201, Center Wing Tank Scavenge System
(9)
AMM 28-31-04/401, Fuel Jettison Valve Actuator
(10)
AMM 32-00-30/201, Landing Gear Door Locks
C.
Equipment
(1)
G28010 - Horizontal Stabilizer Sump Drain Tool
(2)
702800-2 - Drain Tool Assembly, APCO, Whittier, CA
(3)
Container(s) - to collect fuel and of these capacities:
(a)
Reserve tanks - 5 U.S. gallons (20 liters)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
28-26-00
ALL ú ú 04 Page 202 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
PRESSURE REFUEL STATION
SEE A
PRESSURE REFUEL STATION
SEE A
REFUEL RECEPTACLE B
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