(2)
The two rotary actuators hold the same load. If one actuator does not operate correctly, its load will be put on the other actuator. This may cause damage to that actuator. Thus, if you replace an actuator because it does not operate, you must replace the other actuator.
CAUTION:_______YOU MUST REPLACE THE TWO ACTUATORS AT THE SAME TIME. IF YOU DO NOT REPLACE THE TWO ACTUATORS, MORE AIRPLANE DAMAGE WILL OCCUR.
(3)
The removal and installation procedures for the rotary actuators at the forward and aft cargo doors are equivalent. But the rotary actuators on the forward cargo door are not interchangeable with the rotary actuators on the aft cargo door.
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B.
C.
D.
A
747-400 MAINTENANCE MANUAL
(4)
The actuators are removed and installed with the cargo door installed.
(5)
You can replace the actuator with the airplane on its gear or on jacks. If the airplane is on its gear, do these steps:
-
Make sure the fuel is divided the same way on each side of the fuselage
-
Make sure the difference between total fuel quantities on each side of the airplane is less than 5000 pounds.
References
(1)
AMM 20-11-28/401, Lockwire
(2)
AMM 25-52-01/401, Containerized Cargo Compartment Ceiling and Sidewall Linings
(3)
AIPC 52-34-01
(4)
AIPC 52-34-03
(5)
AIPC 52-34-09
(6)
OHM 20-50-03Access
(1)
Location Zone 122 Forward Cargo Container Compartment, Forward Half 142 Aft Cargo Container Compartment
(2)
Access Panel 821R Door - Forward Cargo Compartment 822R Door - Aft Cargo Compartment
Procedure
S 424-028
(1)
Make sure that the rotary actuator arm press-fit bushing is installed (OHM 20-50-03).
S 424-011
(2)
Install the rotary actuator to the support structure as follows:
(a)
Put the rotary actuator in a position to install the bolts (View A and View B).
NOTE: Make sure you put the rotary actuator with the support
____ bracket on the aft end of the forward cargo door and on the forward end of the aft cargo door.
(b)
Install the bolts at the forward and aft sides of the rotary actuator.
(c)
Make sure the shims in View C and View B-B are in the correct position before you install the bolts.
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A 747-400 MAINTENANCE MANUAL
(d) Make sure the shims in View D-D position the rotary actuator in the forward and aft direction.
NOTE:____ The self-aligning rotary actuator bearing allows the gap to taper to accomodate floor beam misalignment. The gaps are controlled by the sum of the minimum gap and the maximum gap not to be greater than 0.140 inch. The maximum and minimum gaps are 180 degrees from each other.
(e) (f) Tighten the 5/16-inch bolts to 180-220 pound-inches.Tighten the 1/4-inch bolts to 110-150 pound-inches.
(3) S 414-019Manually raise the door to the full open position.
(4) S 414-020Hold the door in the full open position with a temporary support.
(5) S 414-021Rotate two rotary actuator arms to positive stops in door up position.
(6) S 424-022Measure vertical distance from door hinge to holes in ends of actuator arms. Lower one of the arms away from its mechanical stop, while maintaining other arm against its stop, as required to equalize vertical distance, within | 0.06 inch, between both arms (Fig. 401).
(7) S 434-012Connect the input shaft of the rotary actuator to the torque tube as follows: (a) Turn the input shafts of the rotary actuator to the door open position until the internal driving dogs are engaged.
NOTE:____ The rotation of the input shaft is opposite to the direction the door turns.
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