(a) Remove the axle jack(s) from under the axle(s).
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757 MAINTENANCE MANUAL
JACKING FOR AIRPLANE SUPPORT WITH ENGINE(S) REMOVED -
_____________________________________________________ MAINTENANCE PRACTICES
_____________________
1. General
_______
A. Jacks are not necessary to keep the airplane stable during engine removal. This is possible if the airplane gross weight and center of gravity (CG) are in the SAFE ZONE limits. The SAFE ZONE limits are specified in Figure 201 and Figure 202.
ú B. 757-200 Airplanes
ú The SAFE ZONE limits are specified in Figure 201 and Figure 202.
TASK 07-11-05-582-002
2. Make the Airplane Stable to Prevent Tipping
___________________________________________
A. General
(1)
Find the airplane gross weight. Use approved weight reports and procedures.
(2)
Find the airplane center of gravity (CG) for the applicable airplane configuration. Use component weight and CG data and calculation procedures in the approved weight and balance manuals. Make sure you know the location of all airplane components and equipment. This includes support and test equipment that has been removed, installed, or relocated in the airplane.
ú (3) 757-200 Airplanes Use the gross weight and CG data to find the weight and CG point of operation in Figure 201 and Figure 202.
CAUTION: THE GROUND STABILITY LIMITS DO NOT ALLOW FOR OTHER PRIMARY
_______ COMPONENT REMOVAL. THEY ALSO DO NOT ALLOW FOR MOVEMENT OF PERSONS AND EQUIPMENT IN OR NEAR THE AFT END OF THE FUSELAGE. ALL NECESSARY PRECAUTIONS MUST BE FOLLOWED.
(4) The airplane will remain stable after engine removal if the point of operation is in the SAFE ZONE. But, the point of operation must be in the SAFE ZONE below the GROUND STABILITY LIMIT line.
NOTE: In the hanger, the airplane will be sufficiently stable to
____ permit some movement of persons in the airplane. It will also permit controlled removal of components. This is also correct if the airplane is in a no-wind condition. The lower the operation point is below the GROUND STABILITY LIMIT line, the more stable the airplane becomes after engine removal.
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MAINTENANCE MANUAL
B. References
(1) 07-11-01/201, Jacking Airplane
C. Procedures
S 492-001
(1) If the operation point is in the CAUTION ZONE and above the GROUND STABILITY LIMIT line, make the airplane stable. Use one of the procedures that follow (Ref 07-11-01):
(a) Use accepted weight and CG procedures to move the point of operation into the SAFE ZONE.
NOTE: On a two engine removal, the best possible solution
____ might be, to remove and install one engine at a time. Do this to get a point of operation satisfactory for maintenance.
(b) Install the airplane jack at the tail jack point to prevent airplane tipping.
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64
60
CENTER OF GRAVITY (% MAC)
56
52
48
44
40
36
32
28
AIRPLANE WEIGHT (1000 POUNDS)
Center of Gravity and Gross Weight Limits for Removal of One Engine
Figure 201 (Sheet 1)
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