-
Remove the Power Plant with the PT90-E (Optional)
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Remove the Power Plant with the Crane and Overhead Sling (Optional)
-
Install the Power Plant with the Bootstrap Equipment (Recommended)
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Install the Power Plant with the PT90-E (Optional)
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Install the Power Plant with the Crane and Overhead Sling (Optional)
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Put the Airplane Back to Its Usual Condition.
B.
You can use the bootstrap equipment, the PT90-E or the crane and overhead sling to remove and install an engine. It is necessary to use the platforms and stands to get access to the disconnect points of the power plant. The disconnect points are approximately 13 feet (4 meters) from the ground level.
(1)
The power plant weighs approximately 11,000 pounds when you remove it from the airplane. You must add the weight of the ground support equipment and the persons that are lifted to the weight of the power plant when you calculate the load.
(2)
Before you remove the engine, you must calculate the weight and balance of the airplane to make sure the airplane center of gravity (C.G.) will stay in the safe limits. As an alternative, you can add ballast to the forward cargo compartment until the shock strut pressure of the nose landing gear is 200 psi (1,779 kPa). This shock strut pressure will cause an "X" dimension (AMM 12-15-05/301) of 15 inches (38.1 cm) or less, before the removal of an inboard engine, will make sure the airplane will not move. It is recommended that the most aft airplane C.G. is not more than 38% mean aerodynamic chord (MAC).
(3)
Be very careful not to apply too much force to lift the power plant when it is engaged with the strut.
(4)
During the power plant removal or installation, you must install the approved caps on all openings. During the power plant removal, you must install the caps on all tube ends, ducts and electrical connectors when it is possible after they are disconnected. During the power plant installation, you must not remove the caps until you connect them. You must use the external caps, and not the internal plugs.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
(5)
When the power plant is operated, the mass airflow will cause unwanted objects to go into the power plant. Thus, you must make sure the power plant and area around the power plant is very clean. After you do the removal/installation procedure, you must clean and examine the engine compartment, air inlet, and work area to make sure there are no unwanted objects before the power plant operation.
(6)
With the bootstrap equipment
(a)
Three load cells are used to monitor the loads applied.
(b)
The strut-mounted bootstrap components use a lever hoist in each of the four support legs. The adjustment of the lever hoists lets the power plant move in the pitch and roll direction while it hangs. The pitch is done when you lift or lower the two front or rear hoists together. The roll is done with the front hoists only.
(c)
When you use the bootstrap components, you must make the airplane level to zero | 1/4 degree in the pitch and roll directions.
(7)
The PT90-E Procedure
(a)
This procedure uses the Dendro Maskin PT90-E Universal Engine Change System (referred to as the PT90-E) to hold the weight of the engine.
(b)
A control box controls the PT90-E. When you use the control box, you can control the position of the engine in all directions:
-Vertical
-Transverse
-Axial
-Pitch
-Yaw
-Roll
(c)
The load cells on the bottom of the PT90-E show the forces applied to the engine or the strut.
(d)
If you leave the airplane when the PT90-E touches the airplane, push the AUTOGUARD switch on the PT90-E control box to the in (off) position.
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