# Boeing Alert Service Bulletin 737-57A1296: Revision 2

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- Document: [Boeing Alert Service Bulletin 737-57A1296](https://openairdocs.org/service-documents/boeing/737-57a1296.md)
- Title as filed: Boeing Service Information
- Pages: 438
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### Page 1

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-57A1296
Original Issue: June 13, 2007
Revision 2: April 01, 2015
ATA System: 5714
SUBJECT: WINGS - Center Wing Box - Longitudinal Floor Beams Between Body Station 656 and
Body Station 727 - Inspection, Repair and Preventive Modification
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET
Copyright © 2007 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
1 of 438
5.0

### Page 2

Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
2 of 438
BOEING SERVICE BULLETIN 737-57A1296
ALERTALERT
BLANK PAGE

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Table of Contents
Revision Transmittal Sheet ............................................ 9
Summary ..................................................... 1 3
1. PLANNING INFORMATION ........................................ 1 7
A. Effectivity ............................................... 1 7
1. Airplanes ............................................ 1 7
2. Spares Affected ........................................ 2 9
B. Concurrent Requirements ...................................... 2 9
C. Reason ................................................ 2 9
D. Description .............................................. 3 0
E. Compliance .............................................. 3 2
F. Approval ............................................... 4 7
G. Manpower .............................................. 4 8
H. Weight and Balance Changes .................................... 5 6
I. Electrical Load Data ......................................... 5 7
J. References .............................................. 5 7
1. Existing Data: ......................................... 5 7
2. Data Supplied with this Service Bulletin: ........................... 5 8
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 5 8
K. Publications Affected ........................................ 5 8
L. Interchangeability and Intermixability of Parts ........................... 5 8
M. Software Accomplishment Summary ................................ 5 9
2. MATERIAL INFORMATION ........................................ 6 1
A. Material - Price and Availability ................................... 6 1
B. Industry Support Information .................................... 6 1
C. Parts Necessary for Each Airplane ................................. 6 1
1. Kits/Parts: ........................................... 6 1
2. Parts and Materials Supplied by the Operator: ........................ 6 1
3. Parts Modified and Reidentified: ............................... 7 5
4. Parts Removed and Not Replaced: .............................. 7 6
D. Parts Necessary to Change Spares ................................. 7 6
E. Special Tooling - Price and Availability ............................... 7 6
F. Special Tooling Necessary to do this Service Bulletin ....................... 7 6
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 7 7
A. GENERAL INFORMATION ..................................... 7 7
B. WORK INSTRUCTIONS ....................................... 7 9
FIGURE 1: CENTER WING BOX - LONGITUDINAL FLOOR BEAMS - ACCESS [Group 1-2, 4] .... 9 1
FIGURE 2: CENTER WING BOX - LONGITUDINAL FLOOR BEAMS - ACCESS [Group 3] ...... 9 2
FIGURE 3: CENTER WING BOX - LONGITUDINAL FLOOR BEAM UPPER CHORD INSPECTION AT RBL
24.82 AND LBL 24.82 BETWEEN STA 656 AND STA 685 [Group 3, Configuration 2] . . . 93
FIGURE 4: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB INSPECTION AT LBL 24.82 AND
RBL 24.82 BETWEEN STA 705 AND STA 715 [Group 1-4, Configuration 2] ........ 9 7
FIGURE 5: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB INSPECTION AT LBL 45.57 AND
RBL 45.57 BETWEEN STA 705 AND STA 715 [Group 1-4, Configuration 2] ....... 1 0 0
FIGURE 6: CENTER WING BOX - LONGITUDINAL FLOOR BEAM UPPER CHORD INSPECTION AT LBL
24.82 AND RBL 24.82, STA 727B [Group 1-4, Configuration 2] .............. 1 0 3
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
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Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
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BOEING SERVICE BULLETIN 737-57A1296
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### Page 4

FIGURE 7: CENTER WING BOX - LONGITUDINAL FLOOR BEAM UPPER CHORD INSPECTION AT LBL
45.57 AND RBL 45.57, STA 727B [Group 1-4, Configuration 2] .............. 1 0 7
FIGURE 8: CENTER WING BOX - LONGITUDINAL FLOOR BEAM LOWER CHORD INSPECTION AT
LBL 24.82 AND RBL 24.82 BETWEEN STA 660 AND STA 666 [Group 1, Configuration 2] . 111
FIGURE 9: CENTER WING BOX - LONGITUDINAL FLOOR BEAM LOWER CHORD INSPECTION AT
LBL 24.82 AND RBL 24.82 BETWEEN STA 660 AND STA 666 [Group 2, 4, Configuration 2]
................................................. 1 1 6
FIGURE 10: CENTER WING BOX - LONGITUDINAL FLOOR BEAMS - CLOSE ACCESS [Group 1-2, 4]
................................................. 1 2 1
FIGURE 11: CENTER WING BOX - LONGITUDINAL FLOOR BEAMS - CLOSE ACCESS [Group 3] . 122
FIGURE 12: CENTER WING BOX - LONGITUDINAL FLOOR BEAM LOWER CHORD INSPECTION AT
LBL 24.82 AND RBL 24.82 BETWEEN STA 660 AND STA 666 [Group 3, Configuration 2] . 123
FIGURE 13: CENTER WING BOX - REPAIR/PREVENTIVE MODIFICATION PARTS FOR THE
LONGITUDINAL FLOOR BEAM UPPER CHORD AT BL 24.82 AND STA 656 TO STA 685
[Group 3, Configuration 2] .................................. 1 2 8
FIGURE 14: CENTER WING BOX - LONGITUDINAL FLOOR BEAM UPPER CHORD REPAIR/PREVENTIVE
MODIFICATION AT LBL 24.82 BETWEEN STA 656 AND STA 685 [Group 3, Configuration 2]
................................................. 1 3 2
FIGURE 15: CENTER WING BOX - LONGITUDINAL FLOOR BEAM UPPER CHORD REPAIR/PREVENTIVE
MODIFICATION AT RBL 24.82 BETWEEN STA 656 AND STA 685 [Group 3, Configuration 2]
................................................. 1 3 9
FIGURE 16: CENTER WING BOX - REPAIR PARTS FOR THE LONGITUDINAL FLOOR BEAM WEB AT
BL 24.82 AND BL 45.57 FROM STA 698 TO STA 717 [Group 1-4] ............ 1 4 6
FIGURE 17: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT LBL 24.82 FROM
STA 698 TO STA 717 [Group 1-2, Configuration 2] ..................... 1 4 7
FIGURE 18: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT RBL 24.82 FROM
STA 698 TO STA 717 [Group 1-2, Configuration 2] ..................... 1 5 4
FIGURE 19: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT LBL 24.82 FROM
STA 698 TO STA 717 [Group 3, Configuration 2] ...................... 1 6 1
FIGURE 20: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT RBL 24.82 FROM
STA 698 TO STA 717 [Group 3, Configuration 2] ...................... 1 6 8
FIGURE 21: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT LBL 24.82 FROM
STA 698 TO STA 717 [Group 4, Configuration 2] ...................... 1 7 5
FIGURE 22: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT RBL 24.82 FROM
STA 698 TO STA 717 [Group 4, Configuration 2] ...................... 1 8 2
FIGURE 23: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT LBL 45.57 FROM
STA 698 TO STA 717 [Group 1-2, Configuration 2] ..................... 1 8 9
FIGURE 24: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT RBL 45.57 FROM
STA 698 TO STA 717 [Group 1-2, Configuration 2] ..................... 1 9 6
FIGURE 25: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT LBL 45.57 FROM
STA 698 TO STA 717 [Group 3-4, Configuration 2] ..................... 2 0 3
FIGURE 26: CENTER WING BOX - LONGITUDINAL FLOOR BEAM WEB REPAIR AT RBL 45.57 FROM
STA 698 TO STA 717 [Group 3-4, Configuration 2] ..................... 2 1 0
FIGURE 27: CENTER WING BOX - REPAIR/PREVENTIVE MODIFICATION PARTS FOR THE AFT END
OF THE LONGITUDINAL FLOOR BEAM UPPER CHORD AT LBL 24.82, STA 727B [Group
1-4, Configuration 2] ..................................... 2 1 7
FIGURE 28: CENTER WING BOX - REPAIR OF THE AFT END OF THE LONGITUDINAL FLOOR BEAM
UPPER CHORD AT LBL 24.82, STA 727B [Group 1-4, Configuration 2] ......... 2 2 1
Export Controlled ECCN: 9E991 - BOEING
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Original Issue: June 13, 2007
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4 of 438
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### Page 5

FIGURE 29: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE AFT END OF THE
LONGITUDINAL FLOOR BEAM UPPER CHORD AT LBL 24.82, STA 727B [Group 1-4,
Configuration 2] ........................................ 2 2 8
FIGURE 30: CENTER WING BOX - REPAIR/PREVENTIVE MODIFICATION PARTS FOR THE AFT END
OF THE LONGITUDINAL FLOOR BEAM UPPER CHORD AT RBL 24.82, STA 727B [Group
1-4, Configuration 2] ..................................... 2 3 4
FIGURE 31: CENTER WING BOX - REPAIR OF THE AFT END OF THE LONGITUDINAL FLOOR BEAM
UPPER CHORD AT RBL 24.82, STA 727B [Group 1-4, Configuration 2] ......... 2 3 8
FIGURE 32: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE AFT END OF THE
LONGITUDINAL FLOOR BEAM UPPER CHORD AT RBL 24.82, STA 727B [Group 1-4,
Configuration 2] ........................................ 2 4 5
FIGURE 33: CENTER WING BOX - REPAIR/PREVENTIVE MODIFICATION PARTS FOR THE AFT END
OF THE LONGITUDINAL FLOOR BEAM UPPER CHORD AT LBL 45.57, STA 727B [Group
1-4, Configuration 2] ..................................... 2 5 1
FIGURE 34: CENTER WING BOX - REPAIR OF THE AFT END OF THE LONGITUDINAL FLOOR BEAM
UPPER CHORD AT LBL 45.57, STA 727B [Group 1-4, Configuration 2] ......... 2 5 5
FIGURE 35: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE AFT END OF THE
LONGITUDINAL FLOOR BEAM UPPER CHORD AT LBL 45.57, STA 727B [Group 1-4,
Configuration 2] ........................................ 2 6 2
FIGURE 36: CENTER WING BOX - REPAIR/PREVENTIVE MODIFICATION PARTS FOR THE AFT END
OF THE LONGITUDINAL FLOOR BEAM UPPER CHORD AT RBL 45.57, STA 727B [Group
1-4, Configuration 2] ..................................... 2 6 8
FIGURE 37: CENTER WING BOX - REPAIR OF THE AFT END OF THE LONGITUDINAL FLOOR BEAM
UPPER CHORD AT RBL 45.57, STA 727B [Group 1-4, Configuration 2] ......... 2 7 2
FIGURE 38: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE AFT END OF THE
LONGITUDINAL FLOOR BEAM UPPER CHORD AT RBL 45.57, STA 727B [Group 1-4,
Configuration 2] ........................................ 2 7 9
FIGURE 39: CENTER WING BOX - PREVENTIVE MODIFICATION PARTS FOR THE LONGITUDINAL
FLOOR BEAM WEB AT BL 24.82 AND BL 45.57 FROM STA 698 TO STA 717 [Group 1-4]
................................................. 2 8 5
FIGURE 40: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT LBL 24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 2] . . 286
FIGURE 41: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT RBL 24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 2] . 292
FIGURE 42: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT LBL 24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 2] . . . 298
FIGURE 43: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT RBL 24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 2] . . . 305
FIGURE 44: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT LBL 24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 2] . . . 311
FIGURE 45: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT RBL 24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 2] . . . 318
FIGURE 46: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT LBL 45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 2] . . 325
FIGURE 47: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT RBL 45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 2] . 331
FIGURE 48: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT LBL 45.57 FROM STA 698 TO STA 717 [Group 3-4, Configuration 2] . . 338
FIGURE 49: CENTER WING BOX - PREVENTIVE MODIFICATION OF THE LONGITUDINAL FLOOR BEAM
ASSEMBLY AT RBL 45.57 FROM STA 698 TO STA 717 [Group 3-4, Configuration 2] . 345
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
5 of 438
BOEING SERVICE BULLETIN 737-57A1296
ALERTALERT

### Page 6

FIGURE 50: CENTER WING BOX - LONGITUDINAL FLOOR BEAM TAPERED FILLER LOCATIONS AT
LBL 24.82 AND LBL 45.57 [Group 1-4, Configuration 1] .................. 3 5 1
FIGURE 51: CENTER WING BOX - LONGITUDINAL FLOOR BEAM TAPERED FILLER LOCATIONS AT
RBL 24.82 AND RBL 45.57 [Group 1-4, Configuration 1] .................. 3 5 3
FIGURE 52: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR AND PREVENTIVE
MODIFICATION - REMOVAL AT LBL 24.82 AND LBL 45.57 FROM STA 698 TO STA 717
[Group 1-4, Configuration 1] ................................. 3 5 5
FIGURE 53: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR AND PREVENTIVE
MODIFICATION - REMOVAL AT RBL 24.82 AND RBL 45.57 FROM STA 698 TO STA 717
[Group 1-4, Configuration 1] ................................. 3 5 7
FIGURE 54: CENTER WING BOX - LONGITUDINAL FLOOR BEAM TAPERED FILLER AREA INSPECTION
AT LBL 24.82 AND LBL 45.57 FROM STA 698 TO STA 717 [Group 1-4, Configuration 1] . 359
FIGURE 55: CENTER WING BOX - LONGITUDINAL FLOOR BEAM TAPERED FILLER AREA INSPECTION
AT RBL 24.82 AND RBL 45.57 FROM STA 698 TO STA 717 [Group 1-4, Configuration 1] . 362
FIGURE 56: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] ............. 3 6 5
FIGURE 57: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] ............. 3 6 8
FIGURE 58: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 1] .............. 3 7 1
FIGURE 59: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 1] .............. 3 7 5
FIGURE 60: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 1] .............. 3 7 8
FIGURE 61: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 1] .............. 3 8 1
FIGURE 62: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] ............. 3 8 4
FIGURE 63: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] ............. 3 8 7
FIGURE 64: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
45.57 FROM STA 698 TO STA 717 [Group 3, Configuration 1] .............. 3 9 0
FIGURE 65: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
45.57 FROM STA 698 TO STA 717 [Group 3, Configuration 1] .............. 3 9 3
FIGURE 66: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT LBL
45.57 FROM STA 698 TO STA 717 [Group 4, Configuration 1] .............. 3 9 6
FIGURE 67: CENTER WING BOX - LONGITUDINAL FLOOR BEAM REPAIR - INSTALLATION AT RBL
45.57 FROM STA 698 TO STA 717 [Group 4, Configuration 1] .............. 3 9 9
FIGURE 68: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] . 402
FIGURE 69: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 24.82 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] . 405
FIGURE 70: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 1] . 408
FIGURE 71: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 24.82 FROM STA 698 TO STA 717 [Group 3, Configuration 1] . 412
FIGURE 72: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 1] . 415
FIGURE 73: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 24.82 FROM STA 698 TO STA 717 [Group 4, Configuration 1] . 418
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
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Original Issue: June 13, 2007
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ALERTALERT

### Page 7

FIGURE 74: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] . 421
FIGURE 75: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 45.57 FROM STA 698 TO STA 717 [Group 1-2, Configuration 1] . 424
FIGURE 76: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 45.57 FROM STA 698 TO STA 717 [Group 3, Configuration 1] . 427
FIGURE 77: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 45.57 FROM STA 698 TO STA 717 [Group 3, Configuration 1] . 430
FIGURE 78: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT LBL 45.57 FROM STA 698 TO STA 717 [Group 4, Configuration 1] . 433
FIGURE 79: CENTER WING BOX - LONGITUDINAL FLOOR BEAM PREVENTIVE MODIFICATION -
INSTALLATION AT RBL 45.57 FROM STA 698 TO STA 717 [Group 4, Configuration 1] . 436
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
7 of 438
BOEING SERVICE BULLETIN 737-57A1296
ALERTALERT

### Page 8

Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: June 13, 2007
737-57A1296Revision 2: April 01, 2015
8 of 438
BOEING SERVICE BULLETIN 737-57A1296
ALERTALERT
BLANK PAGE

### Page 9

Commercial 
Airplanes
737
Service Bulletin
ALERT
Revision Transmittal SheetNumber: 737-57A1296Original Issue: June 13, 2007
Revision 2: April 01, 2015
ATA System: 5714
SUBJECT: WINGS - Center Wing Box - Longitudinal Floor Beams Between Body Station 656 and
Body Station 727 - Inspection, Repair and Preventive Modification
This revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service
bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin
mandatory.
Federal Aviation Administration (FAA) Airworthiness Directives AD 2008-09-13, AD 2008-05-06 and AD 98-11-04
R1 are related to this service bulletin.
More work is necessary on the airplane(s) changed in accordance with Revision 1 of this service bulletin. For
operators that did not install tapered fillers near STA 716 during the repair or the preventive modification done
in accordance with Revision 1 of this service bulletin, install two tapered fillers on each longitudinal floor beam
in accordance with Part 6 of the Work Instructions.
REASON FOR REVISION
Revision 2 is sent to add instruction steps to install tapered fillers required for repairs or preventive modifications
at STA 716, BL 24.82 and BL 45.57 inadvertently omitted from Revision 1 of this service bulletin. Omission of
the tapered fillers creates a preload condition that may promote undetected fatigue cracking and subsequent
failure of the BL 24.82 and BL 45.57 Longitudinal Floor Beams. Revision 2 elevates this service bulletin to an
ALERT level status.
These sections were changed:
1. Changed Summary Background and Action sections.
2. Paragraph 1.A., Effectivity - Added Group/Configurations to provide instructions for operators that have
or have not accomplished the prior issue of this service bulletin and have or have not installed a repair
or preventive modification. Added Group 5.
3. Paragraph 1.C., Reason - Changed the Reason paragraph.
4. Paragraph 1.D., Description - Changed the Description paragraph. Added Group 5 to Affected
Maintenance Zones.
Export Controlled ECCN: 9E991 - BOEING
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### Page 10

5. Paragraph 1.E., Compliance - Changed Tables 1-4 to provide corrective actions for "No Crack Found"
conditions. Added Table 5 to provide compliance data for tapered filler inspections and corrective
actions. Added Group 5 compliance data.
6. Paragraph 1.F., Approval - Changed the Approval paragraph.
7. Paragraph 1.G., Manpower - Changed manpower requirements.
8. Paragraph 1.H., Weight and Balance - Added Weight and Balance data for Group 1-4 Configuration 1
and Group 5.
9. Paragraph 1.J., References - Changed References.
10. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - Changed fastener requirements for
Group 1-4 Configuration 2 airplanes to accommodate tapered filler installation, clarified nutplate sizing,
and added optional material thicknesses. Added Group 1-4 Configuration 1 and Group 5 material and
requirements.
11. Paragraph 3.A. General Information - Changed General Notes.
12. Paragraph 3.B., Work Instructions - Changed Work Instructions PART 1-5. Added Work Instructions
for Group 1-4 Configuration 1 and Group 5.
13. Figures 1 and 10, Changed step table.
14. Figure 16, Changed applicability.
15. Figures 3-7, 27, 30, 36, and 39, Changed applicability and step table.
16. Figures 8, 9, and 12, Changed applicability, step table, and fastener code table.
17. Figures 13, 25, 26, and 33, Changed applicability, illustrations, and step table.
18. Figures 14, 15, 17-24, 28, 29, 31, 32, 34, 35, 37, 38, and 40-49, Changed applicability, illustrations,
step table, and fastener code table.
19. Added Figures 50-79.
The data given in Information Notice 737-57-1296 IN01 and IN02 and IN03 is included in this Revision.
737-57-1296 IN01 was sent to tell operators the correct instructions for inspecting Group 3 airplanes. 737-57-1296
IN02 was sent to provide additional information to operators including fastener pattern information, fastener
quantity, clip-on nutplate, primer and enamel. 737-57-1296 IN03 was sent to provide information to operators
about the tapered fillers.
The data given in Alternative Method of Compliance Notice 737-57-1296-AMOC-02 is included in this revision.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location
of important changes.
Pages with no vertical lines have no important changes.
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REVISION HISTORY
June 13, 2007Original Issue:
September 26, 2012Revision 1:
April 01, 2015Revision 2:
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BLANK PAGE

### Page 13

Commercial 
Airplanes
737
Service Bulletin
ALERT
SummaryNumber: 737-57A1296Original Issue: June 13, 2007
Revision 2: April 01, 2015
ATA System: 5714
SUBJECT: WINGS - Center Wing Box - Longitudinal Floor Beams Between Body Station 656 and
Body Station 727 - Inspection, Repair and Preventive Modification
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH
1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OWNER.
CONCURRENT REQUIREMENTS
None.
BACKGROUND
This service bulletin gives instructions to inspect the center wing box longitudinal floor beams for any crack at
Left Buttock Line (LBL) 24.82, Right Buttock Line (RBL) 24.82, LBL 45.57 and RBL 45.57. Extended fatigue
cracks in the longitudinal floor beams could reduce the structural integrity of the center wing box area. This
service bulletin also gives instructions to repair cracks found during inspection or to install preventive modifications
that terminate repeat inspections. Accomplishment of this service bulletin will make sure that any crack is detected
and repaired at an early stage. Undetected fatigue cracking could adversely affect the structural integrity of the
floor, resulting in loss of controllability of the airplane and/or rapid loss of cabin pressure.
Boeing has received several reports of cracks in the center wing box longitudinal floor beams of 737 Classic
airplanes discovered during normal maintenance inspection. The cracks were found in the longitudinal floor
beam web, upper chord and lower chord at LBL 24.82, RBL 24.82, LBL 45.57 and RBL 45.57 between Station
(STA) 656 and STA 727B. The airplanes had between 17,000 and 70,000 total flight cycles. These are fatigue
cracks attributed to cyclic pressurization loads, fuel loads and passenger loads. Similar longitudinal floor beam
cracks at BBL 0 have been previously reported and is the subject of Boeing Service Bulletin 737-57-1210.
Revision 1 of this service bulletin inadvertently omitted the installation of tapered fillers during the repair and
preventive modification of the longitudinal floor beam webs. Omission of the tapered fillers creates a preload
condition that may promote undetected fatigue cracking and subsequent failure of the BL 24.82 and BL 45.57
Longitudinal Floor Beams. Revision 2 of this service bulletin instructs operators that have accomplished repairs
or preventive modifications in accordance with Revision 1 of this service bulletin to determine if tapered fillers
are installed and to perform subsequent corrective actions.
Boeing Service Related Problem (SRP) 737-SRP-57-0202 is related to this service bulletin.
Boeing Fleet Team Digest (FTD) 737 FTD 57-14002 is related to this service bulletin.
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### Page 14

This table is provided to operators for planning purposes only. Refer to the applicable sections for more
information.
ReferenceAffectedPlanning Data
Paragraph 1.A.2., Spares AffectedNoSpares Affected
Paragraph 1.E., Compliance and Paragraph
1.F., Approval
YesAD Related
Paragraph 1.H., Weight and Balance ChangesYesWeight and Balance Change
Paragraph 1.I., Electrical Load DataNoElectrical Load Changed
Paragraph 1.K., Publications AffectedNoPublications Affected
Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew
Operations Manual and/or FAA Approved Air-
plane Flight Manual)
Paragraph 2.C.1., Kits/PartsNoKits/Parts Required
Paragraph 2.C.2., Parts and Materials Supplied
by the Operator
YesOperator Supplied Material
Paragraph 2.F., Special Tooling Necessary to
do this Service Bulletin
NoSpecial Tooling Required
ACTION
Group 1-4, Configuration 1:
1. Make sure tapered fillers are installed on the longitudinal floor beams at STA 716, BL 24.82 and BL
45.57. If tapered fillers are installed, no further action is required.
2. If tapered fillers are not installed, remove existing repair or preventive modification and do a Detailed
Inspection and fastener open hole High Frequency Eddy Current inspection for any crack at the affected
tapered filler area.
3. If any crack is found, contact Boeing and do the work instructed by Boeing. If no crack is found, install
tapered fillers and new repair or new preventive modification.
4. Installation of a repair or preventive modification in accordance with Boeing Service Bulletin 737-57A1296
Revision 02 or later is terminating action for repeat inspections.
Group 1-4, Configuration 2:
1. Remove and keep seats, carpets and floor panels above the center wing box.
2. Do Detailed Inspections for any crack in the longitudinal floor beam upper chord at LBL 24.82, RBL
24.82, between STA 656 and STA 685. Do High Frequency Eddy Current (HFEC) inspections for any
crack in the longitudinal floor beam lower chord at LBL 24.82 and RBL 24.82, between STA 660 and
STA 666. Do Detailed Inspections for any crack in the longitudinal floor beam web at LBL 24.82, RBL
24.82, LBL 45.57 and RBL 45.57 between STA 705 to STA 715. Do Detailed Inspections for any crack
in the horizontal flange of the longitudinal floor beam upper chord at LBL 24.82, RBL 24.82, LBL 45.57
and RBL 45.57 at STA 727B.
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3. If any crack is found, make the necessary parts and repair the structure in accordance with Paragraph
3.B.3., Accomplishment Instructions. If no crack is found, close the access and do repeat inspections
as given in Paragraph 1.E., Compliance or, install the preventive modification.
4. Installation of a repair or preventive modification in accordance with Boeing Service Bulletin 737-57A1296
Revision 02 or later is terminating action for repeat inspections.
Group 5:
1. Contact Boeing to get instructions for the inspection, repair/preventive modification and do the work
instructed by Boeing.
NOTE: Boeing Service Bulletin 737-57-1210 and Boeing Service Bulletin 737-57-1139 have similar access
requirements as this service bulletin.
EFFECTIVITY
737-100/-200/-300/-400/-500 Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.
COMPLIANCE
Refer to Paragraph 1.E, Compliance.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service
bulletin.
MANPOWER
Refer to Paragraph 1.G., Manpower.
MATERIAL INFORMATION
Operator Supplied Parts/Materials.
Refer to Paragraph 2.A., Material - Price and Availability.
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### Page 16 (OCR)

BOEING SERVICE BULLETIN 737-57A1296
ALERT  ALERT
DO DETAILED INSPECTIONS FOR ANY CRACK IN
THE LONGITUDINAL FLOOR BEAM UPPER CHORD.
IF ANY CRACK IS FOUND, INSTALL A REPAIR.
TO TERMINATE REPEAT INSPECTIONS, INSTALL
THE PREVENTIVE MODIFICATION.
STA
727B  RBL
STA  45.57
STA 727  RBL
706  24.82
BBL
ALBL
STA  24.82
656
LBL
FWD C  _45.57
STA
540
DO DETAILED INSPECTIONS
FOR ANY CRACK IN THE
LONGITUDINAL FLOOR BEAM
WEB. IF ANY CRACK IS
FOUND, INSTALL A REPAIR.
TO TERMINATE REPEAT
INSPECTIONS, INSTALL THE
PREVENTIVE MODIFICATIONS.
DO DETAILED INSPECTIONS FOR ANY CRACK IN THE LONGITUDINAL FLOOR BEAM
UPPER CHORD. IF ANY CRACK IS FOUND, INSTALL A REPAIR. TO TERMINATE
REPEAT INSPECTIONS, INSTALL THE PREVENTIVE MODIFICATION.DO OPEN HOLE
HIGH FREQUENCY EDDY CURRENT INSPECTIONS OF THE LONGITUDINAL FLOOR
BEAM LOWER CHORD. IF ANY CRACK IS FOUND, CONTACT BOEING FOR FURTHER
INSTRUCTIONS.
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### Page 17

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-57A1296
Original Issue: June 13, 2007
Revision 2: April 01, 2015
ATA System: 5714
SUBJECT: WINGS - Center Wing Box - Longitudinal Floor Beams Between Body Station 656 and
Body Station 727 - Inspection, Repair and Preventive Modification
THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH
1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO
THE NEW OWNER.
1.    PLANNING INFORMATION
A. Effectivity
1. Airplanes
Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
This service bulletin is for the airplanes shown below.
DESCRIPTIONCONFIGURATIONGROUP
737-100/200 Airplanes that will need three fastener holes inspected
at LBL 24.82 and RBL 24.82 between STA 660 and STA 666 and
have no angle on the inboard side of BL 24.82 and BL 45.57 at STA
706 and STA 717.
-1
Airplanes that have done Revision 1 of the service bulletin AND
Installed the repair or preventive modification
1
Airplanes that have not done Revision 1 of the service bulletin OR
did NOT install the repair or preventive modification
2
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### Page 18

DESCRIPTIONCONFIGURATIONGROUP
737-200 Airplanes that will need two fastener holes inspected at LBL
24.82 and RBL 24.82 between STA 660 and STA 666 and have no
angle on the inboard side of BL 24.82 and BL 45.57 at STA 706 and
STA 717.
-2
Airplanes that have done Revision 1 of the service bulletin AND
Installed the repair or preventive modification
1
Airplanes that have not done Revision 1 of the service bulletin OR
did NOT install the repair or preventive modification
2
All 737-300/400/500 Airplanes.-3
Airplanes that have done Revision 1 of the service bulletin AND
Installed the repair or preventive modification
1
Airplanes that have not done Revision 1 of the service bulletin OR
did NOT install the repair or preventive modification
2
737-200 Airplanes that will need two fastener holes inspected at LBL
24.82 and RBL 24.82 between STA 660 and STA 666 and have an
angle on the inboard side of BL 24.82 and BL 45.57 at STA 706 and
STA 717.
-4
Airplanes that have done Revision 1 of the service bulletin AND
Installed the repair or preventive modification
1
Airplanes that have not done Revision 1 of the service bulletin OR
did NOT install the repair or preventive modification
2
737-100/200 Airplanes. Line Number 1 - 291-5
Airplane Models:
737-100, 737-200, 737-300, 737-400, 737-500
GroupVariable Number
5PA001 - PA022
5PA099
5PA231 - PA232
5PC001 - PC005
5PG001 - PG075
5PG199
5PG201 - PG230
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GroupVariable Number
5PG251 - PG255
5PG271 - PG279
5PG301 - PG314
5PG331 - PG332
5PG351 - PG356
5PG375
5PG401 - PG403
5PG431 - PG442
5PG471 - PG475
5PG501 - PG505
5PG571 - PG583
1PG584 - PG586
5PG621 - PG630
5PG651 - PG652
5PG701 - PG705
1PH001
1PH011 - PH012
2PH013
2PH021 - PH024
5PH701 - PH715
5PH731 - PH732
5PH741 - PH742
2PH743
5PJ001 - PJ002
2PJ003 - PJ009
5PJ031 - PJ032
5PJ071 - PJ072
5PJ101 - PJ104
2PJ105 - PJ119
1PJ201 - PJ219
3PJ301 - PJ302
3PJ551 - PJ561
3PJ601 - PJ615
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GroupVariable Number
3PJ811
3PJ816 - PJ817
2PK026 - PK029
2PK041 - PK053
2PK061 - PK070
2PK081 - PK082
2PK091 - PK099
2PK101 - PK103
2PK111 - PK120
2PK141 - PK146
2PK201 - PK204
2PK211 - PK215
4PK216 - PK220
2PK221 - PK223
2PK231 - PK241
2PK251 - PK258
2PK271 - PK274
2PK281 - PK289
2PK291
2PK301 - PK318
2PK341
2PK351 - PK361
2PK391
2PK431 - PK433
2PK451 - PK452
2PK461 - PK469
2PK495
2PK501 - PK504
2PK511 - PK514
4PK515
2PK519
2PK521 - PK525
4PK526 - PK528
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GroupVariable Number
2PK541 - PK564
4PK565
2PK581
2PK591 - PK599
2PK601 - PK617
2PK621 - PK637
2PK641 - PK642
2PK661 - PK664
4PK665 - PK666
2PK671 - PK680
4PK681
2PK691 - PK697
2PK711 - PK716
2PK731 - PK749
4PK750 - PK765
2PK771 - PK779
2PK801 - PK804
2PK819 - PK827
2PK830
2PK861 - PK863
2PK871 - PK874
2PK881 - PK884
2PK901 - PK932
4PK933 - PK938
2PK971 - PK974
2PL001 - PL028
2PL061
2PL081
2PL101 - PL113
2PL151
2PL171 - PL172
2PL201 - PL203
2PL221
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GroupVariable Number
2PL401 - PL417
2PL421
2PL441
2PL451 - PL454
4PL455 - PL456
2PL471
2PL491
2PL501 - PL506
2PL551 - PL562
2PL581
2PL601 - PL602
4PL603
2PL611
2PL621 - PL623
4PL624 - PL626
2PL631 - PL632
5PL711 - PL712
5PL716
2PL717 - PL725
1PL726 - PL728
2PL729 - PL735
1PL736 - PL742
2PL743 - PL745
4PL746 - PL747
1PL756
2PL758
1PL761
2PL762 - PL770
2PL781 - PL788
2PL793
5PL801 - PL803
2PM001 - PM006
2PM016 - PM017
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GroupVariable Number
2PM021 - PM023
2PM051 - PM062
4PM063 - PM066
2PM101 - PM117
4PM118 - PM119
2PM141 - PM142
4PM171
4PM181
4PM251 - PM255
4PM281 - PM283
3PM381 - PM399
3PM401 - PM417
3PM541 - PM564
2PN001 - PN002
2PN021 - PN032
4PN033 - PN043
2PN081 - PN086
2PN101 - PN112
4PN113 - PN117
4PN131 - PN163
4PN401 - PN420
4PN431 - PN433
4PN451 - PN456
4PN471 - PN474
4PN481
4PN491 - PN493
4PN501 - PN502
4PN511 - PN512
4PN521
3PP001 - PP054
3PP101 - PP169
3PP181 - PP199
3PP201 - PP205
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GroupVariable Number
3PP221
3PP231 - PP243
3PP281 - PP286
3PP301 - PP305
3PP351 - PP353
3PP376 - PP384
3PP391 - PP393
3PP401 - PP440
3PP471 - PP475
3PP501 - PP522
3PP631 - PP634
3PP651 - PP652
3PP671 - PP699
3PP701 - PP733
3PP771 - PP779
3PP801 - PP808
3PP821 - PP827
3PP831 - PP848
3PP851 - PP852
3PP861 - PP877
3PP891 - PP899
3PP901 - PP936
3PP946 - PP948
3PP951 - PP952
3PP961 - PP967
3PP981 - PP991
3PP993
3PQ001 - PQ016
3PQ026 - PQ041
3PQ051 - PQ092
3PQ101 - PQ199
3PQ201 - PQ202
3PQ221 - PQ237
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GroupVariable Number
3PQ241 - PQ243
3PQ251 - PQ267
3PQ281 - PQ299
3PQ301 - PQ307
3PQ331 - PQ332
3PQ341 - PQ348
3PQ361 - PQ373
3PQ391 - PQ395
3PQ401 - PQ418
3PQ421
3PQ431 - PQ438
3PQ447 - PQ448
3PQ451
3PQ454
3PQ471 - PQ475
3PQ479 - PQ481
3PQ486 - PQ487
3PQ491 - PQ493
3PQ771 - PQ772
3PQ791 - PQ793
3PQ801 - PQ805
3PQ931 - PQ935
3PQ951
3PQ971 - PQ997
3PR001 - PR017
3PR021 - PR034
3PR041 - PR045
3PR061 - PR072
3PR077 - PR082
3PR091 - PR092
3PR096
3PR101
3PR121 - PR122
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GroupVariable Number
3PR131 - PR132
3PR141 - PR143
3PR161 - PR172
3PR181
3PS601 - PS631
3PS636 - PS638
3PS641 - PS644
3PS651 - PS657
3PS666 - PS669
3PS691 - PS692
3PS701 - PS706
3PS751 - PS799
3PS811
3PS836 - PS837
3PS841 - PS846
3PS851 - PS852
3PS856
3PS861 - PS863
3PS866 - PS868
3PS871 - PS874
3PS896 - PS897
3PS901 - PS941
3PS956 - PS957
3PS961 - PS963
3PS971 - PS978
3PT001 - PT015
3PT021 - PT031
3PT041 - PT064
3PT101 - PT105
3PT121 - PT138
3PT146 - PT148
3PT161 - PT170
3PT181 - PT188
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GroupVariable Number
3PT211 - PT220
3PT295
3PT301 - PT309
3PT331 - PT360
3PT381 - PT399
3PT401 - PT438
3PT501 - PT517
3PT561 - PT565
3PT581 - PT586
3PT611 - PT621
3PT641 - PT644
3PT651 - PT656
3PT671 - PT672
3PT681 - PT685
3PT701 - PT703
3PT716 - PT717
3PT721 - PT725
3PT801 - PT834
3PT851 - PT854
3PT871 - PT886
3PT901 - PT930
3PT971 - PT973
3PT981 - PT985
3PT996
3PU001 - PU025
3PU301
3PU311 - PU313
3PV001 - PV055
3PV201 - PV209
3PV226 - PV229
3PV231 - PV237
3PV271 - PV272
3PV281 - PV287
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GroupVariable Number
3PV296
3PV301 - PV302
3PV351
3PV356 - PV357
3PW001 - PW054
3PW061 - PW068
3PW072
3PW086 - PW088
3PW091 - PW094
3PW101 - PW102
3PW106
3PW111 - PW120
3PW156 - PW157
3PW161 - PW171
3PW201 - PW252
3PW261 - PW268
3PW271 - PW276
3PW278
3PW281 - PW293
3PW296
3PW301 - PW327
3PW401 - PW408
3PW411 - PW418
3PW421 - PW424
3PW431 - PW435
3PW441 - PW450
3PW461 - PW467
3PW501 - PW504
3PW511 - PW522
3PW524 - PW550
3PW556 - PW557
3PW561 - PW564
3PW571 - PW576
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GroupVariable Number
3PW591 - PW596
3PW611 - PW622
3PW631 - PW637
3PW661 - PW662
3PW681 - PW683
3PW701 - PW702
3PW711 - PW717
3PW741 - PW742
3PW761
3PW771
3PW831
3PW851 - PW856
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
This service bulletin gives instructions to inspect the center wing box longitudinal floor beams for any
crack at Left Buttock Line (LBL) 24.82, Right Buttock Line (RBL) 24.82, LBL 45.57 and RBL 45.57.
Extended fatigue cracks in the longitudinal floor beams could reduce the structural integrity of the center
wing box area. This service bulletin also gives instructions to repair cracks found during inspection or
to install preventive modifications that terminate repeat inspections. Accomplishment of this service
bulletin will make sure that any crack is detected and repaired at an early stage. Undetected fatigue
cracking could adversely affect the structural integrity of the floor, resulting in loss of controllability of
the airplane and/or rapid loss of cabin pressure.
Boeing has received several reports of cracks in the center wing box longitudinal floor beams of 737
Classic airplanes discovered during normal maintenance inspection. The cracks were found in the
longitudinal floor beam web, upper chord and lower chord at LBL 24.82, RBL 24.82, LBL 45.57 and
RBL 45.57 between Station (STA) 656 and STA 727B. The airplanes had between 17,000 and 70,000
total flight cycles. These are fatigue cracks attributed to cyclic pressurization loads, fuel loads and
passenger loads. Similar longitudinal floor beam cracks at BBL 0 have been previously reported and
is the subject of Boeing Service Bulletin 737-57-1210.
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### Page 30

Revision 1 of this service bulletin inadvertently omitted the installation of tapered fillers during the repair
and preventive modification of the longitudinal floor beam webs. Omission of the tapered fillers creates
a preload condition that may promote undetected fatigue cracking and subsequent failure of the BL
24.82 and BL 45.57 Longitudinal Floor Beams. Revision 2 of this service bulletin instructs operators
that have accomplished repairs or preventive modifications in accordance with Revision 1 of this service
bulletin to determine if tapered fillers are installed and to perform subsequent corrective actions.
Boeing Service Related Problem (SRP) 737-SRP-57-0202 is related to this service bulletin.
Boeing Fleet Team Digest (FTD) 737 FTD 57-14002 is related to this service bulletin.
The FAA has issued an AD which requires incorporation of this service bulletin.
Revision 1 is sent to provide repair and preventive modification instructions for longitudinal floor beams
between Body Station (STA) 656 and STA 727 and to correct the instructions for the inspection of
group 3 airplanes.
Revision 2 is sent to add instruction steps to install tapered fillers required for repairs or preventive
modifications at STA 716, BL 24.82 and BL 45.57 inadvertently omitted from Revision 1 of this service
bulletin. Omission of the tapered fillers creates a preload condition that may promote undetected fatigue
cracking and subsequent failure of the BL 24.82 and BL 45.57 Longitudinal Floor Beams. Revision 2
elevates this service bulletin to an ALERT level status.
D. Description
Group 1-4, Configuration 1:
1. Make sure tapered fillers are installed on the longitudinal floor beams at STA 716, BL 24.82 and
BL 45.57. If tapered fillers are installed, no further action is required.
2. If tapered fillers are not installed, remove existing repair or preventive modification and do a Detailed
Inspection and fastener open hole High Frequency Eddy Current inspection for any crack at the
affected tapered filler area.
3. If any crack is found, contact Boeing and do the work instructed by Boeing. If no crack is found,
install tapered fillers and new repair or new preventive modification.
4. Installation of a repair or preventive modification in accordance with Boeing Service Bulletin
737-57A1296 Revision 02 or later is terminating action for repeat inspections.
Group 1-4, Configuration 2:
1. Remove and keep seats, carpets and floor panels above the center wing box.
2. Do Detailed Inspections for any crack in the longitudinal floor beam upper chord at LBL 24.82,
RBL 24.82, between STA 656 and STA 685. Do High Frequency Eddy Current (HFEC) inspections
for any crack in the longitudinal floor beam lower chord at LBL 24.82 and RBL 24.82, between
STA 660 and STA 666. Do Detailed Inspections for any crack in the longitudinal floor beam web
at LBL 24.82, RBL 24.82, LBL 45.57 and RBL 45.57 between STA 705 to STA 715. Do Detailed
Inspections for any crack in the horizontal flange of the longitudinal floor beam upper chord at LBL
24.82, RBL 24.82, LBL 45.57 and RBL 45.57 at STA 727B.
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### Page 31

3. If any crack is found, make the necessary parts and repair the structure in accordance with
Paragraph 3.B.3., Accomplishment Instructions. If no crack is found, close the access and do
repeat inspections as given in Paragraph 1.E., Compliance or, install the preventive modification.
4. Installation of a repair or preventive modification in accordance with Boeing Service Bulletin
737-57A1296 Revision 02 or later is terminating action for repeat inspections.
Group 5:
1. Contact Boeing to get instructions for the inspection, repair/preventive modification and do the
work instructed by Boeing.
NOTE: Boeing Service Bulletin 737-57-1210 and Boeing Service Bulletin 737-57-1139 have similar
access requirements as this service bulletin.
Revision 1 - No more work is necessary on airplanes inspected in accordance with the original issue
of this service bulletin. Repeat inspections are required for any previously installed repairs. To terminate
these inspections, install repairs or preventive modifications in accordance with Boeing Service Bulletin
737-57-1296 Revision 01 or later.
Revision 2 - More work is necessary on the airplane(s) changed in accordance with Revision 1 of this
service bulletin. For operators that did not install tapered fillers for the repair or the preventive modification
near the STA 716 locations, install two tapered fillers on each longitudinal floor beam in accordance
with Part 6 of the accomplishment instructions.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1-2, 4:
Affected Maintenance Zones
ZoneModel
2-16, 2-17, 2-21737-200
Group 3:
Affected Maintenance Zones
ZoneModel
216, 217, 221737-300, 737-400, 737-500
Group 5:
Affected Maintenance Zones
ZoneModel
2-16, 2-17, 2-21737-100, 737-200
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### Page 32

E. Compliance
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this
service bulletin mandatory.
Federal Aviation Administration Airworthiness Directives AD 2008-09-13, AD 2008-05-06 and AD
98-11-04 R1 are related to this service bulletin.
Do the required actions in accordance with Paragraph 3. Accomplishment Instructions.
When more than one OPTION is given, do only one of the OPTION numbers. When more than one
ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for
that CONDITION number or OPTION number.
Group 1, Configuration 2:
Table 1 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at Left Buttock
Line (LBL) 24.82 and Right
Buttock Line (RBL) 24.82, be-
tween Station (STA) 705 and
STA 715 in accordance with
Accomplishment Instructions
paragraphs 3.B.2.b.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraphs
3.B.3.b.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraphs
3.B.3.b.(1)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (a)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
24.82 and RBL 24.82, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraphs
3.B.2.b.(1).
No crack
found.
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### Page 33

Group 1, Configuration 2:
Table 1 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at LBL 45.57
and RBL 45.57, between STA
705 and STA 715 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.b.(2).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(2)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(2)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (b)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
45.57 and RBL 45.57, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.b.(2).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 24.82 and RBL
24.82, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(b).
Any crack
found on the
right side.
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### Page 34

Group 1, Configuration 2:
Table 1 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
6,000 Flight Cy-
cles. (c)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
24.82 and RBL 24.82, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 45.57 and RBL
45.57, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(2).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (d)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
45.57 and RBL 45.57, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(2).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a High Frequency Eddy
Current (HFEC) open hole in-
spection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.f.(1).
All airplanes.
-Before further flight.Contact Boeing for repair in-
structions and do the work in-
structed by Boeing.
Any crack
found.
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### Page 35

Group 1, Configuration 2:
Table 1 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
6,000 Flight Cy-
cles.
--Do a repeat HFEC open hole
inspection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.f.(1).
No crack
found.
(a) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.b.(1).
(b) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.b.(2).
(c) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(1).
(d) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(2).
(e) Installation of a repair done in accordance with the Accomplishment Instructions of this service bulletin
terminates the repeat inspections for the repaired area only.
Group 2, Configuration 2:
Table 2 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at Left Buttock
Line (LBL) 24.82 and Right
Buttock Line (RBL) 24.82, be-
tween Station (STA) 705 and
STA 715 in accordance with
Accomplishment Instructions
paragraph 3.B.2.b.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(1)(b).
Any crack
found on the
right side.
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### Page 36

Group 2, Configuration 2:
Table 2 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
6,000 Flight Cy-
cles. (a)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
24.82 and RBL 24.82, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.b.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at LBL 45.57
and RBL 45.57, between STA
705 and STA 715 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.b.(2).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(2)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.b.(2)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (b)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
45.57 and RBL 45.57, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.b.(2).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 24.82 and RBL
24.82, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(a).
Any crack
found on the
left side.
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### Page 37

Group 2, Configuration 2:
Table 2 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (c)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
24.82 and RBL 24.82, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 45.57 and RBL
45.57, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(2).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (d)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
45.57 and RBL 45.57, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(2).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a High Frequency Eddy
Current (HFEC) open hole in-
spection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.g.(1).
All airplanes.
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### Page 38

Group 2, Configuration 2:
Table 2 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Before further flightContact Boeing for repair in-
structions and do the work in-
structed by Boeing.
Any crack
found.
6,000 Flight Cy-
cles.
--Do a repeat HFEC open hole
inspection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.g.(1).
No crack
found.
(a) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.b.(1).
(b) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.b.(2).
(c) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(1).
(d) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(2).
(e) Installation of a repair done in accordance with the Accomplishment Instructions of this service bulletin
terminates the repeat inspections for the repaired area only.
Group 3, Configuration 2:
Table 3 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam upper chord at Left
Buttock Line (LBL) 24.82 and
Right Buttock Line (RBL)
24.82, between Station (STA)
656 and STA 685 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.a.(1).
All airplanes.
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### Page 39

Group 3, Configuration 2:
Table 3 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
(f)Before further flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.a.(1)(a).
Any crack
found on the
left side that
does not ex-
tend into the
upper chord
horizontal
flange.
(f)Before further flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.a.(1)(b).
Any crack
found on the
right side that
does not ex-
tend into the
upper chord
horizontal
flange.
-Before further flight.Contact Boeing for repair in-
structions and do the work in-
structed by Boeing.
Any crack
found on the
left or right
side that ex-
tends into the
upper chord
horizontal
flange.
7,000 Flight Cy-
cles. (a)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam upper chord
at LBL 24.82 and RBL 24.82,
between STA 656 and STA
685 in accordance with Accom-
plishment Instructions para-
graph 3.B.2.a.(1).
No crack
found.
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at LBL 24.82
and RBL 24.82, between STA
705 and STA 715 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.a.(2).
All airplanes.
(f)Before further flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.a.(2)(a).
Any crack
found on the
left side.
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### Page 40

Group 3, Configuration 2:
Table 3 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
(f)Before further flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.a.(2)(b).
Any crack
found on the
right side.
7,000 Flight Cy-
cles. (b)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
24.82 and RBL 24.82, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.a.(2).
No crack
found.
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at LBL 45.57
and RBL 45.57, between STA
705 and STA 715 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.d.(1).
All airplanes.
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.d.(1)(a).
Any crack
found on the
left side.
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.d.(1)(b).
Any crack
found on the
right side.
7,000 Flight Cy-
cles. (c)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
45.57 and RBL 45.57, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.d.(1).
No crack
found.
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 24.82 and RBL
24.82, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(1).
All airplanes.
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### Page 41

Group 3, Configuration 2:
Table 3 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(a).
Any crack
found on the
left side.
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(b).
Any crack
found on the
right side.
7,000 Flight Cy-
cles. (d)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
24.82 and RBL 24.82, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(1).
No crack
found.
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 45.57 and RBL
45.57, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(2).
All airplanes.
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(a).
Any crack
found on the
left side.
(f)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(b).
Any crack
found on the
right side.
7,000 Flight Cy-
cles. (e)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
45.57 and RBL 45.57, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(2).
No crack
found.
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### Page 42

Group 3, Configuration 2:
Table 3 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 7,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a High Frequency Eddy
Current (HFEC) open hole in-
spection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.a.(3).
All airplanes.
-Before further flight.Contact Boeing for repair in-
structions and do the work in-
structed by Boeing.
Any crack
found.
7,000 Flight Cy-
cles.
--Do a repeat HFEC open hole
inspection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.a.(3).
No crack
found.
(a) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.a.(1).
(b) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.a.(2).
(c) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.d.(1).
(d) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(1).
(e) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(2).
(f) Installation of a repair done in accordance with the Accomplishment Instructions of this service bulletin
terminates the repeat inspections for the repaired area only.
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### Page 43

Group 4, Configuration 2:
Table 4 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at Left Buttock
Line (LBL) 24.82 and Right
Buttock Line (RBL) 24.82, be-
tween Station (STA) 705 and
STA 715 in accordance with
Accomplishment Instructions
paragraph 3.B.2.c.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.c.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.c.(1)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (a)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
24.82 and RBL 24.82, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.c.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack in the longitudinal
floor beam web at LBL 45.57
and RBL 45.57, between STA
705 and STA 715 in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.d.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.d.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.d.(1)(b).
Any crack
found on the
right side.
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### Page 44

Group 4, Configuration 2:
Table 4 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
6,000 Flight Cy-
cles. (b)
--Do a repeat Detailed Inspec-
tion for any crack in the longi-
tudinal floor beam web at LBL
45.57 and RBL 45.57, be-
tween STA 705 and STA 715
in accordance with Accomplish-
ment Instructions paragraph
3.B.2.d.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 24.82 and RBL
24.82, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(1).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(a).
Any crack
found on the
left side.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(1)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (c)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
24.82 and RBL 24.82, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(1).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a Detailed Inspection for
any crack at the aft end of the
longitudinal floor beam upper
chord at LBL 45.57 and RBL
45.57, STA 727B in accor-
dance with Accomplishment
Instructions paragraph
3.B.2.e.(2).
All airplanes.
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(a).
Any crack
found on the
left side.
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### Page 45

Group 4, Configuration 2:
Table 4 - Longitudinal Floor Beam Inspection and Repair
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever Occurs
Later)
ActionCondition
(e)Before Further Flight.Do the repair in accordance
with Accomplishment Instruc-
tions paragraph 3.B.3.e.(2)(b).
Any crack
found on the
right side.
6,000 Flight Cy-
cles. (d)
--Do a repeat Detailed Inspec-
tion for any crack at the aft
end of the longitudinal floor
beam upper chord at LBL
45.57 and RBL 45.57, STA
727B in accordance with Ac-
complishment Instructions
paragraph 3.B.2.e.(2).
No crack
found.
-Within 6,000 Flight
Cycles after April 8,
2008 (the effective
date of AD 2008-05-
06).
Before 20,000 Total
Flight Cycles.
Do a High Frequency Eddy
Current (HFEC) open hole in-
spection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.g.(1).
All airplanes.
-Before further flight.Contact Boeing for repair in-
structions and do the work in-
structed by Boeing.
Any crack
found.
6,000 Flight Cy-
cles.
--Do a repeat HFEC open hole
inspection for any crack in the
longitudinal floor beam lower
chord at LBL 24.82 and RBL
24.82, between STA 660 and
STA 666 in accordance with
Accomplishment Instructions
paragraph 3.B.2.g.(1).
No crack
found.
(a) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.c.(1).
(b) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.d.(1).
(c) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(1).
(d) To terminate repeat inspections, accomplish the preventive modification in accordance with Accomplishment
Instructions paragraph 3.B.4.e.(2).
(e) Installation of a repair done in accordance with the Accomplishment Instructions of this service bulletin
terminates the repeat inspections for the repaired area only.
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### Page 46

Group 1-4, Configuration 1:
Table 5 - Tapered Filler - Inspection and Installation
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 7000 flight
cycles after the
Revision 2 date of
this service bul-
letin.
OPTION 1:
Do a review of mainte-
nance records in accor-
dance with Accomplish-
ment Instructions para-
graph 3.B.6.a.(1)(a) to
make sure tapered fillers
are installed. (a)
All airplanes.
OPTION 2:
Do an On-Airplane inspec-
tion in accordance with
Accomplishment Instruc-
tions paragraph
3.B.6.a.(2)(a) and (b) to
make sure tapered fillers
are installed.
--No further action is re-
quired.
CONDITION 1:
TAPERED FILLERS IN-
STALLED
-Before Further
Flight.
ACTION 1-
Remove existing repair or
preventive modification in
accordance with Accom-
plishment Instructions
paragraph 3.B.6.c.(2).
CONDITION 2:
TAPERED FILLERS NOT
INSTALLED
ACTION 2-
Do a Detailed Inspection
for any crack and a fasten-
er open hole High Fre-
quency Eddy Current
(HFEC) inspection for any
crack in accordance with
Accomplishment Instruc-
tions paragraph
3.B.6.c.(3).
-Before Further
Flight.
Contact Boeing for repair
instructions and do the
work instructed by Boe-
ing.
CONDITION 3:
ANY CRACK FOUND
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### Page 47

Group 1-4, Configuration 1:
Table 5 - Tapered Filler - Inspection and Installation
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before Further
Flight.
Install tapered fillers and
new repair or new preven-
tive modification in accor-
dance with Accomplish-
ment Instructions para-
graph 3.B.6.c.(3)(b)1) or
2).
CONDITION 4:
NO CRACK FOUND
(a) A review of the maintenance records is acceptable for compliance with the requirements
of this action provided the installation of tapered fillers can be conclusively determined
from that review.
Group 5:
Within 120 days after the Revision 2 date of this service bulletin, contact Boeing to get compliance
information for the inspection, repair/preventive modification and do the work instructed by Boeing.
F. Approval
This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified
in this service bulletin comply with the applicable regulations and are FAA approved, as well as European
Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved
airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on
the airplane in its original Boeing delivery configuration or as modified by other approved Boeing
changes.
The Manager, Seattle Aircraft Certification Office, FAA, approves the inspections in Paragraph 1.E,
Tables 1, 2, 4, and 5 of this service bulletin, Revision 2, as a method of compliance (MOC) to paragraph
(g) of AD 98-11-04 R1 for the inspection of Structurally Significant Item F-46 of the Supplemental
Structural Inspection Document, D6-37089 affected by the repair/preventive modification. This MOC
only applies to the areas inspected in accordance with this service bulletin, Revision 2 and to the
airplanes identified in this service bulletin, Revision 2. At or above 66,000 total flight cycles, the
inspections of this service bulletin, Revision 2, Tables 1, 2, 4, and 5 remain in place and supersede
the F-46 inspections for the LBL 24.82, RBL 24.82, LBL 45.57, and RBL 45.57 floor beams at the
specified locations until the preventive modification or repair specified in Tables 1, 2, 4, and 5 as
appropriate, of this service bulletin, Revision 2, is accomplished. Operators of 737-100/-200 airplanes
must revise their FAA-approved maintenance or inspection program to comply with paragraph (g) of
AD 98-11-04 R1 when incorporating the changes specified in this service bulletin, Revision 2. All
provisions of AD 98-11-04 R1 that are not specifically referenced in the above statements remain fully
applicable and must be complied with.
The Manager, Seattle Aircraft Certification Office, FAA, approves the inspections defined in Paragraph
1.E., Compliance Tables 3 and 5 of this service bulletin, Revision 2, as an alternative method of
compliance (AMOC) to paragraphs (g) and (h) of AD 2008-09-13 for the inspection of SSI F-46 of the
Supplemental Structural Inspection Document, D6-82669, affected by the repair/preventive modification.
This AMOC only applies to the areas inspected in accordance with this service bulletin, Revision 2 and
to the airplanes identified in this service bulletin, Revision 2. At or above 66,000 total flight cycles, the
inspections of this service bulletin, Revision 2, Tables 3 and 5 remain in place and supersede the F-46
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### Page 48

inspections for the LBL 24.82, RBL 24.82, LBL 45.57, and RBL 45.57 floor beams at the specified
locations until the preventive modification or repair specified in Tables 3 and 5 of this service bulletin,
Revision 2, is accomplished. Operators of 737-300/-400/-500 airplanes must revise their FAA-approved
maintenance or inspection program to comply with paragraph (g) and (h) of AD 2008-09-13 when
incorporating the changes specified in this service bulletin, Revision 2. All provisions of AD 2008-09-13
that are not specifically referenced in the above statements remain fully applicable and must be complied
with.
The Manager, Seattle Aircraft Certification Office, FAA, approves accomplishment of the inspection
methods, repair, and preventive modification defined in Paragraph 1.E., Compliance, Tables 1 through
5 of this service bulletin, Revision 2, as an alternative method of compliance (AMOC) to the
corresponding requirements of paragraph (f) of AD 2008-05-06. All provisions of AD 2008-05-06 that
are not specifically referenced in the above statement remain fully applicable and must be complied
with.
Where this service bulletin specifies to contact Boeing for repair instructions: Before further flight, repair
using a method approved in accordance with the procedures specified in paragraph (h) of AD
2008-05-06.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected
by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this service bulletin.
G. Manpower
The tables below show an estimate of the task hours necessary to do this service bulletin for each
airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with
operator task hour data if necessary. The estimate does not include lost time. These are some examples
of lost time:
 Time to adjust to the workplace
 Time to schedule the work
 Time to inspect the work
 Time to cure the materials
 Time to make the parts
 Time to find the tools.
Group 1, Configuration 2:
Table 1: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002Open Access
2.254.502FIGURE 1
2.002.001FIGURE 4
2.002.001FIGURE 5
0.500.501FIGURE 6
0.500.501FIGURE 7
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### Page 49

Group 1, Configuration 2:
Table 1: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
1.251.251FIGURE 8
2.254.502FIGURE 10
(a)(a)-FIGURE 16
4.0016.004FIGURE 17
4.0016.004FIGURE 18
4.0016.004FIGURE 23
4.0016.004FIGURE 24
(a)(a)-FIGURE 27
4.759.502FIGURE 28
3.256.502FIGURE 29
(a)(a)-FIGURE 30
4.759.502FIGURE 31
3.256.502FIGURE 32
(a)(a)-FIGURE 33
4.759.502FIGURE 34
3.507.002FIGURE 35
(a)(a)-FIGURE 36
4.759.502FIGURE 37
3.507.002FIGURE 38
(a)(a)-FIGURE 39
5.7511.502FIGURE 40
5.7511.502FIGURE 41
5.7511.502FIGURE 46
5.7511.502FIGURE 47
4.008.002Close Access
90.25206.25TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
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### Page 50

Group 2, Configuration 2:
Table 2: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002Open Access
2.254.502FIGURE 1
2.002.001FIGURE 4
2.002.001FIGURE 5
0.500.501FIGURE 6
0.500.501FIGURE 7
1.251.251FIGURE 9
2.254.502FIGURE 10
(a)(a)-FIGURE 16
4.0016.004FIGURE 17
4.0016.004FIGURE 18
4.0016.004FIGURE 23
4.0016.004FIGURE 24
(a)(a)-FIGURE 27
4.759.502FIGURE 28
3.256.502FIGURE 29
(a)(a)-FIGURE 30
4.759.502FIGURE 31
3.256.502FIGURE 32
(a)(a)-FIGURE 33
4.759.502FIGURE 34
3.507.002FIGURE 35
(a)(a)-FIGURE 36
4.759.502FIGURE 37
3.507.002FIGURE 38
(a)(a)-FIGURE 39
5.7511.502FIGURE 40
5.7511.502FIGURE 41
5.7511.502FIGURE 46
5.7511.502FIGURE 47
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### Page 51

Group 2, Configuration 2:
Table 2: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002Close Access
90.25206.25TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 3, Configuration 2:
Table 3: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modifi-
cation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002Open Access
1.002.002FIGURE 2
2.502.501FIGURE 3
2.002.001FIGURE 4
2.002.001FIGURE 5
0.500.501FIGURE 6
0.500.501FIGURE 7
1.002.002FIGURE 11
1.251.251FIGURE 12
(a)(a)-FIGURE 13
4.509.002FIGURE 14
4.509.002FIGURE 15
(a)(a)-FIGURE 16
4.0016.004FIGURE 19
4.0016.004FIGURE 20
4.0016.004FIGURE 25
4.0016.004FIGURE 26
(a)(a)-FIGURE 27
4.759.502FIGURE 28
3.256.502FIGURE 29
(a)(a)-FIGURE 30
4.759.502FIGURE 31
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### Page 52

Group 3, Configuration 2:
Table 3: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modifi-
cation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
3.256.502FIGURE 32
(a)(a)-FIGURE 33
4.759.502FIGURE 34
3.507.002FIGURE 35
(a)(a)-FIGURE 36
4.759.502FIGURE 37
3.507.002FIGURE 38
(a)(a)-FIGURE 39
3.0012.004FIGURE 42
3.0012.004FIGURE 43
5.7511.502FIGURE 48
5.7511.502FIGURE 49
4.008.002Close Access
93.75222.75TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 4, Configuration 2:
Table 4: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002Open Access
2.254.502FIGURE 1
2.002.001FIGURE 4
2.002.001FIGURE 5
0.500.501FIGURE 6
0.500.501FIGURE 7
1.251.251FIGURE 9
2.254.502FIGURE 10
(a)(a)-FIGURE 16
4.0016.001FIGURE 21
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### Page 53

Group 4, Configuration 2:
Table 4: Center Wing Box Longitudinal Floor Beam Inspection, Repair and Preventive Modi-
fication.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.0016.001FIGURE 22
4.0016.001FIGURE 25
4.0016.001FIGURE 26
(a)(a)-FIGURE 27
4.759.502FIGURE 28
3.256.502FIGURE 29
(a)(a)-FIGURE 30
4.759.502FIGURE 31
3.256.502FIGURE 32
(a)(a)-FIGURE 33
4.759.502FIGURE 34
3.507.002FIGURE 35
(a)(a)-FIGURE 36
4.759.502FIGURE 37
3.507.002FIGURE 38
(a)(a)-FIGURE 39
3.0012.004FIGURE 44
3.0012.004FIGURE 45
5.7511.52FIGURE 48
5.7511.52FIGURE 49
4.008.002Close Access
84.75207.25TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 1-2, Configuration 1:
Table 5: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002OPEN ACCESS
2.254.502FIGURE 1
2.254.502FIGURE 10
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### Page 54

Group 1-2, Configuration 1:
Table 5: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
(a)(a)-FIGURE 16
(a)(a)-FIGURE 39
0.250.251FIGURE 50
0.250.251FIGURE 51
1.503.002FIGURE 52
1.503.002FIGURE 53
3.003.001FIGURE 54
3.003.001FIGURE 55
4.5018.004FIGURE 56
4.5018.004FIGURE 57
4.5018.004FIGURE 62
4.5018.004FIGURE 63
4.0016.004FIGURE 68
4.0016.004FIGURE 69
4.0016.004FIGURE 74
4.0016.004FIGURE 75
4.008.002Close Access
56.00173.50TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 3, Configuration 1:
Table 6: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002OPEN ACCESS
2.254.502FIGURE 2
2.254.502FIGURE 11
(a)(a)-FIGURE 16
(a)(a)-FIGURE 39
0.250.251FIGURE 50
0.250.251FIGURE 51
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### Page 55

Group 3, Configuration 1:
Table 6: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
1.503.002FIGURE 52
1.503.002FIGURE 53
3.003.001FIGURE 54
3.003.001FIGURE 55
4.5018.004FIGURE 58
4.5018.004FIGURE 59
4.5018.004FIGURE 64
4.5018.004FIGURE 65
4.0016.004FIGURE 70
4.0016.004FIGURE 71
4.0016.004FIGURE 76
4.0016.004FIGURE 77
4.008.002Close Access
56.00173.50TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 4, Configuration 1:
Table 7: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.008.002OPEN ACCESS
2.254.502FIGURE 1
2.254.502FIGURE 10
(a)(a)-FIGURE 16
(a)(a)-FIGURE 39
0.250.251FIGURE 50
0.250.251FIGURE 51
1.503.002FIGURE 52
1.503.002FIGURE 53
3.003.001FIGURE 54
3.003.001FIGURE 55
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### Page 56

Group 4, Configuration 1:
Table 7: Center Wing Box Longitudinal Floor Beam Tapered Filler Installation.
Elapsed HoursTask-HoursNumber of Per-
sons
Task
4.5018.004FIGURE 60
4.5018.004FIGURE 61
4.5018.004FIGURE 66
4.5018.004FIGURE 67
4.0016.004FIGURE 72
4.0016.004FIGURE 73
4.0016.004FIGURE 78
4.0016.004FIGURE 79
4.008.002Close Access
56.00173.50TOTAL FOR EACH AIRPLANE
(a) Time to make parts is not included in Boeing estimates.
Group 5:
Contact Boeing for Manpower requirements.
H. Weight and Balance Changes
Group 1-4, Configuration 1:
None.
Group 1-4, Configuration 2:
Table 1: Repair/Preventive Modifications for 737-100/200/300/400/500 Airplanes
Change in Moment
(Pound-Inches)
Change in Weight
(Pounds)
Repair/Preventive Modification Loca-
tion
+ 5,630+ 8.4Floor Beam Upper Chord at LBL 24.82
and RBL 24.82, from STA 656 to STA
685 (2 repairs/preventive modifications
- refer to FIGURE 14 and FIGURE 15).
Group 1-4, Configuration 2:
Table 2: Repair for 737-100/200/300/400/500 Airplanes
Change in Moment
(Pound-Inches)
Change in Weight
(Pounds)Repair Location
+ 2,550+ 3.6Floor Beam Web at LBL 24.82, RBL
24.82, LBL 45.57 and RBL 45.57, from
STA 698 to STA 717 (4 repairs - refer to
FIGURE 17 - FIGURE 26).
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### Page 57

Group 1-4, Configuration 2:
Table 2: Repair for 737-100/200/300/400/500 Airplanes
Change in Moment
(Pound-Inches)
Change in Weight
(Pounds)Repair Location
+ 1,300+ 1.7Aft end of the Longitudinal Floor Beam
Upper Chord at LBL 24.82, RBL 24.82,
LBL 45.57 and RBL 45.57, STA 727B (4
repairs - refer to FIGURE 28, FIGURE
31, FIGURE 34 and FIGURE 37).
Group 1-4, Configuration 2:
Table 3: Preventive Modification for 737-100/200/300/400/500 Airplanes
Change in Moment
(Pound-Inches)
Change in Weight
(Pounds)Preventive Modification Location
+ 1,415+ 2.0Longitudinal Floor Beam Assembly at
LBL 24.82, RBL 24.82, LBL 45.57 and
RBL 45.57, from STA 698 to STA 717
(4 preventive modifications - refer to
FIGURE 39 - FIGURE 49).
+ 1,300+ 1.7Aft end of the Longitudinal Floor Beam
Upper Chord at LBL 24.82, RBL 24.82,
LBL 45.57 and RBL 45.57, STA 727B (4
preventive modifications - refer to FIG-
URE 29, FIGURE 32, FIGURE 35 and
FIGURE 38).
Group 5:
Contact Boeing for Weight and Balance Changes.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data:
a. Boeing Service Bulletin 737-57-1139, 737-57-1210
b. Boeing Service Letter 737-SL-51-042
c. Boeing Service Related Problem (SRP) 737-SRP-57-0202
d. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2008-05-06, 2008-09-13,
98-11-04 R1
e. Standard Overhaul Practices Manual (SOPM) 20-10-03, 20-20-02, 20-41-02, 20-43-03,
20-50-01 , 20-50-19, 20-50-20
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### Page 58

f. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19
g. 737 Fleet Team Digest (FTD) 57-14002
h. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00 Procedure 16 , Part 6, 51-00-00
Procedure 4 or Procedure 23
i. 737-100/200 Aircraft Maintenance Manual (AMM) 25-22-00 , 25-22-11, 25-27-100, 25-27-101,
53-21-0, 53-21-00
j. 737-100/200 Structural Repair Manual (SRM) 51-30-5
k. 737-300/400/500 Aircraft Maintenance Manual (AMM) 25-22-00, 25-27-15, 53-21-00
l. 737-300 Structural Repair Manual (SRM) 51-20-06, 51-40-05
m. 737-400 Structural Repair Manual (SRM) 51-40-05
n. 737-500 Structural Repair Manual (SRM) 51-40-05
2. Data Supplied with this Service Bulletin:
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin:
TitleDrawing Number
Floor Beam Installation - Wing Center Section65-45410
These drawings were used to prepare this service bulletin. These drawings are not necessary to
make the specified changes, and are not supplied with this service bulletin. These drawings may
not be applicable to all airplane configurations or operators.
K. Publications Affected
1. Publications:
None.
2. Damage Tolerance Based Structural Inspections:
Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue
Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the
Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected
are contained in Paragraph 1.E., Compliance of this service bulletin.
L. Interchangeability and Intermixability of Parts
Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.
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### Page 59

M. Software Accomplishment Summary
Not affected.
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### Page 60

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