and to prevent secondary damage to the airplane.
WARNING: BE CAREFUL IN HIGH WINDS. DO NOT USE JACKS TO LIFT THE AIRPLANE IN VERY HIGH WINDS (MORE THAN 40 MPH, 35 KNOTS OR 64 KM/HOUR).
G. Lift the Airplane with Jacks
(1)
First you must change the airplane to a level attitude. Use an attitude gage or the plumb bob in the wheel well to monitor the movement of the airplane (see Section 8 of the Maintenance Manual). You can also use a different tool (carpenter’s level). Put this tool on the ceiling of the wheel well or put this tool on the keel beam. If you cannot get access to these areas, put this tool on the floor of the airplane.
(2)
Apply an initial (preload) pressure of 1,000 pounds (454 kilograms) to each jack when you start to lift the airplane. Make sure that you have safe conditions at all of the jack points. Then apply pressure to all of the jacks at the same time until each jack has its calculated load. Do not apply a jack load that is more than the permitted load at a jack point. Usually, if you have the maximum permitted load, there is an error in your procedures. Examine the weight at that jack point, the airplane weight and the CG location.
CAUTION: BE CAREFUL IF THE FUEL TANKS ARE NOT FULL. WHEN YOU CHANGE THE AIRPLANE TO A LEVEL ATTITUDE, THE MOVEMENT OF THE CENTER OF GRAVITY CAN BE LARGE.
(3) Jack Procedures, Airplane Without a Level Attitude
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IMPORTANT DATA ABOUT THE JACKS
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(a)
Lift the low point first. Because of the turn effect of the airplane, this jack point will move through an arc. Possibly, you will have horizontal movements as large as 10 to 15 inches (25 to 38 cm). These movements will cause a side load on the jacks that is too large.
(b)
Make small vertical jack movements of approximately 6 to 8 inches (15 to 20 cm). Put supports (cribs) in the area of the jack points to hold the airplane after each jack movement. Then align the jacks. Also, put more supports below the jacks if it is necessary.
(c)
Do this small movement procedure until the airplane has a level attitude.
NOTE: POSSIBLY YOU CAN DEFLATE THE STRUTS (OLEOS) AND THE TIRES OF THE OTHER LANDING GEAR. THEN YOU CAN HAVE A LEVEL AIRPLANE ATTITUDE MORE QUICKLY.
H. Jack Procedures, Airplane With a Level Attitude
(1)
Use the jacks to lift the airplane in a procedure that keeps it in a level attitude. If you do not do this, you will put horizontal loads on the jacks. Frequently monitor the plumb bob, or other tools, for all dangerous movements of the airplane.
(2)
There are no alternative jack points on the wing where you can hold the airplane with jacks. If you must align the jacks, you must use other equipment to hold the airplane. Then you can also add more support below the jacks if it is necessary.
