LIFTING AND SHORING

航空

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LIFTING AND SHORING

航空

LIFTING
1. General
A. Two general types of airplane lifting will be covered in this chapter, airplane jacking for normal
maintenance, and lifting damaged airplanes.
B. When the airplane is jacked for normal maintenance, the main and auxiliary jacking points are
used. The airplane is usually jacked for weighing, leveling, alignment checks, and gear
retraction.
C. Procedures for lifting and recovery of damaged aircraft are contained in the Boeing Document
D6-40146, 707, 727, 737 AIRPLANE RECOVERY.
D. When necessary to obtain additional tail clearance for positioning an airplane in a hangar or
storage area, a nose lift dolly may be used to tilt the airplane. The nose lift dolly raises the
airplane nose section, causing the airplane to rotate about the main gear.

LIFTING AIRPLANE FOR MAINTENANCE
1. General
A. Lifting the airplane for maintenance is accomplished by using conventional airplane jacks at
jacking points provided on the wing, forward and aft body or at the nose and main landing gear.
The jacking points on the wing and body are provided with receptacles for the attachment of
removable ball-type jack adapters. The nose and main landing gear jacking points are integral
with the landing gear.

JACK AIRPLANE
1. General
A. The airplane is provided with three main jacking points and four auxiliary jacking points. The
main jacking points are wing jacking point D and aft body jacking point G. The four auxiliary
jacking points consist of one stabilizing and three landing gear jacking points. The stabilizing
jacking point is forward body jacking point C. The three landing gear jacking points are points
E-F at each main gear axle and points A-B under the nose gear axle. See Fig. 201 and 202 for
jacking point locations, jacking point maximum loads, wing and body jack adapters and
applicable jacks.
B. The airplane may be jacked at any gross weight provided the maximum load of any jacking
point is not exceeded. However, if the airplane is supported entirely by the three main jacks and
the stabilizing jack, the maximum jacking weight of the airplane must not be exceeded
(Fig. 202). At any weight, the airplane center of gravity must be within the forward and aft limits
prior to jacking.
C. The axle jacking points are designed to permit the changing of two flat tires on the same
landing gear while the airplane is at maximum taxi weight. The maximum load on an axle
jacking point must not be exceeded.
2. Equipment and Materials
A. Main Landing Gear Oleo Lock Assembly - F80016 or F80234-1
B. Nose Landing Gear Shock Strut Restrainer - 6ME65-73762 or F70263-1
C. Wing and Fuselage Jacks, Axle Jacks and Jack Pad Adapters (Fig. 202)
(1) Wing Jacks - Regent Model 986CT (or equivalent)
(2) Body Jacks - Regent Model 8156 (or equivalent)
(3) Axle Jacks - Regent Model 5923 (or equivalent)
D. Nose and Main Landing Gear Ground Lockpins - F72735 (flyaway)
3. Raise Airplane
CAUTION: DO NOT EXCEED 1 INCH CLEARANCE FROM JACK RAM LOCKNUT TO COLLAR
AS JACK IS BEING RAISED OR LOWERED. EXCESSIVE CLEARANCE CAN
RESULT IN DAMAGE TO AIRPLANE STRUCTURE IF JACK FAILS.
DO NOT OPERATE THE MAIN DECK CARGO DOOR WHILE JACK FORCE IS
BEING APPLIED TO THE JACK POINT AT THE FORWARD BODY. OPERATION OF
THE DOOR CAN RESULT IN DAMAGE TO BOTH THE DOOR AND THE FUSELAGE.
A. Ensure that the maximum allowable jacking gross weight will not be exceeded and that C.G.
conditions are such that airplane jack points allowable loads are not exceeded, and that all
landing gear downlocks are in place.

B. Set stabilizer, aileron and rudder trim controls to O.
C. Trip flight recorder circuit breakers before jacking so that recorded data is not lost while airplane
is on jacks.
D. Head airplane into the wind if in an exposed area.
CAUTION: DO NOT JACK AIRPLANE AT JACK POINTS D, G, AND C IF WINDS EXCEED
35 MILES PER HOUR.
E. When airplane is being jacked for weighing, leveling, or for general requirements, the landing
gear shock struts may be deflated and locked in the compressed position using oleo lock
assemblies at the main gear and nose gear. The airplane does not have to be jacked as high
with the shock struts locked in the compressed position.
CAUTION: DO NOT PERFORM THIS STEP IF AIRPLANE IS BEING RAISED TO PERMIT A
GEAR RETRACTION TEST. SUCH A TEST REQUIRES THAT GEAR BE FULLY
EXTENDED.
IF SHOCK STRUT IS NOT COMPLETELY DEFLATED PRIOR TO OLEO LOCK
ASSEMBLY INSTALLATION, OLEO LOCK ASSEMBLY MAY BE DAMAGED
DURING JACKING OPERATION.
TO AVOID SERIOUS DAMAGE TO SHOCK STRUT, DO NOT JACK AIRPLANE
WEIGHT OFF WHEELS WITH SHOCK STRUTS INFLATED ABOVE NORMAL
PRESSURE.
F. When airplane is being jacked for gear retraction test or when airplane is jacked and shock
struts are not deflated and locked, it should be noted that the main gear shock strut is canted to
trail 1.85 degrees aft of the vertical axis. When jacking the airplane, normal oleo extension on
the 88.15-degree angle causes aft wheel movement on the ground up to a maximum of 0.55
inch. If wheels are chocked or parking brakes are set during the jacking or lowering operation,
wheel movement will result in sliding of the chocks or scuffing of tires on the pavement.
CAUTION: HORIZONTAL REACTION LOADS DUE TO SCUFFING OR SLIDING WILL BE
TRANSMITTED THROUGH STRUCTURE TO THE JACK PADS, RESULTING IN
A TENDENCY TO TIP THE JACKS OVER.
G. Jacking the airplane for weighing, leveling, gear retraction test, or for general requirements
open the following circuit breakers.
(1) Drain, Mast. Air.
H. Remove jack pad adapter recess fillers and fasteners at position D.
NOTE: Aft body jacking adapter F80000-7 is a threaded rod with a machined semiball on one
end. The F80000-7 is inserted into a jack pad fitting that is an integral part of the
airplane structure.

I. Install jack pad adapters and position jacks per Fig. 201 making sure that one leg of jack at
position D points straight forward.
CAUTION: WHEN INSTALLING JACK PAD ADAPTERS, USE ATTACH BOLTS AS
SPECIFIED IN FIG. 202 OR STRUCTURAL DAMAGE MAY RESULT.
STABILIZING JACK MUST BE USED DURING WINDY CONDITIONS.
STABILIZER JACK MUST BE PRELOADED TO A MAXIMUM OF 5000 POUNDS
AT WINDS OF 35 MPH.
NOTE: Jacks must be equipped with pressure gages and a conversion table to give pounds
of load at each jack point.
J. After jacks have been positioned and jacking is ready to proceed, ensure that wheel chocks are
removed and that parking brakes have been released.
K. Use plumb bob and leveling scale in right wheel well to establish lateral level and longitudinal
attitude while raising airplane.
NOTE: The plumb bob method is accurate enough for general jacking requirements,
weighing, and gear retraction only. If more accurate leveling is required, refer to
Chapter 8, Leveling.
L. Station one man at each jack to operate the jack and to ensure that the jack loads are not
exceeded. Raise airplane in a level attitude, using jacks at wing jacking pad D and at aft
fuselage jacking pad G, until landing gear clears the ground.
CAUTION: JACKS AT PAD D MUST BE RAISED PRIOR TO OR SIMULTANEOUSLY WITH
JACK AT JACK PAD G. RAISING TAIL JACK AHEAD OF WING JACKS MAY
OVERLOAD TAIL JACK POINT BY FORCING NOSE OF AIRPLANE DOWN ON
NOSE GEAR, OR IT MAY OVERLOAD TAIL JACK POINT AND NOSE
STABILIZING JACK POINT WHEN LATTER IS USED.
JACK AIRPLANE IN A LEVEL ATTITUDE TO PREVENT INTRODUCING SIDE
LOADS INTO THE JACK POINTS THAT COULD CAUSE JACKS TO SLIP OFF
THE PADS OR OVERLOAD THE JACK POINTS AND DAMAGE STRUCTURE.
NOTE: When airplane is being jacked for gear retraction test, include 3 inches for tire arc
sweep clearance plus 1 inch additional clearance.