# Boeing Alert Service Bulletin 737-57A1323: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2015-1983; AD 2016-03-01 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 737-57A1323](https://openairdocs.org/service-documents/boeing/737-57a1323.md)
- Title as filed: U.S. DOT/FAA - SB-737-57A1323-00
- Pages: 102
- PDF: https://openairdocs.org/files/sha256/ff/56/ff56d801772cfb58ac403f676d957bea046d4ead8143e264d20da0e049e1fedc
- Page: https://openairdocs.org/service-documents/boeing/737-57a1323/file/ff56d801772c

## Text

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### Page 1

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-57A1323
Original Issue: December 05, 2014
ATA System: 5711
SUBJECT: WINGS - Front Spar - Wing Front Spar Lower Chord Between WBL 114 and WBL 183
and Wing Skin Common to the Nacelle Outboard Side Load Fitting Fasteners at WBL
198.6 - Inspection
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 © 2014 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Unpublished Work.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: December 05, 2014
737-57A1323
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### Page 3

Table of Contents
Summary ...................................................... 5
1. PLANNING INFORMATION ........................................ 9
A. Effectivity ................................................ 9
1. Airplanes ............................................. 9
2. Spares Affected ........................................ 2 1
B. Concurrent Requirements ...................................... 2 1
C. Reason ................................................ 2 1
D. Description .............................................. 2 1
E. Compliance .............................................. 2 3
F. Approval ............................................... 2 7
G. Manpower .............................................. 2 7
H. Weight and Balance Changes .................................... 2 9
I. Electrical Load Data ......................................... 2 9
J. References .............................................. 2 9
1. Existing Data: ......................................... 2 9
2. Data Supplied with this Service Bulletin: ........................... 3 0
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 0
K. Publications Affected ........................................ 3 0
L. Interchangeability and Intermixability of Parts ........................... 3 0
M. Software Accomplishment Summary ................................ 3 0
2. MATERIAL INFORMATION ........................................ 3 1
A. Material - Price and Availability ................................... 3 1
B. Industry Support Information .................................... 3 1
C. Parts Necessary for Each Airplane ................................. 3 1
1. Kits/Parts ............................................ 3 1
2. Parts and Materials Supplied by the Operator ........................ 3 1
3. Parts Modified and Reidentified ................................ 3 2
4. Parts Removed and Not Replaced .............................. 3 2
D. Parts Necessary to Change Spares ................................. 3 3
E. Special Tooling - Price and Availability ............................... 3 3
F. Special Tooling Necessary to do this Service Bulletin ....................... 3 3
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 5
A. GENERAL INFORMATION ..................................... 3 5
B. WORK INSTRUCTIONS ....................................... 3 6
FIGURE 1: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI) [Group 2] .................... 4 5
FIGURE 2: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI) [Group 2] .................... 4 9
FIGURE 3: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI) [Group 3] .................... 5 3
FIGURE 4: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI) [Group 3] .................... 5 7
FIGURE 5: LEFT WING AT (WBL) 198.6 - HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE
INSPECTION [Group 3] .................................... 6 1
FIGURE 6: RIGHT WING AT (WBL) 198.6 - HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE
INSPECTION [Group 3] .................................... 6 4
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FIGURE 7: LEFT WING AT (WBL) 198.6 - HIGH FREQUENCY EDDY CURRENT (HFEC) MOUSE HOLE
INSPECTION [Group 3] .................................... 6 7
FIGURE 8: RIGHT WING AT (WBL) 198.6 - HIGH FREQUENCY EDDY CURRENT (HFEC) MOUSE HOLE
INSPECTION [Group 3] .................................... 7 0
FIGURE 9: LEFT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - FASTENER
INSTALLATION [Group 3] ................................... 7 3
FIGURE 10: RIGHT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - FASTENER
INSTALLATION [Group 3] ................................... 7 6
FIGURE 11: LEFT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED FASTENER
INSTALLATION [Group 3] ................................... 7 9
FIGURE 12: RIGHT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED
FASTENER INSTALLATION [Group 3] ............................ 8 2
FIGURE 13: LEFT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED FASTENER
INSTALLATION [Group 3] ................................... 8 5
FIGURE 14: RIGHT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED
FASTENER INSTALLATION [Group 3] ............................ 8 8
FIGURE 15: LEFT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED FASTENER
INSTALLATION [Group 3] ................................... 9 1
FIGURE 16: RIGHT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED
FASTENER INSTALLATION [Group 3] ............................ 9 4
FIGURE 17: LEFT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED FASTENER
INSTALLATION [Group 3] ................................... 9 7
FIGURE 18: RIGHT WING OUTBOARD SIDE LOAD NACELLE SUPPORT FITTING - OVERSIZED
FASTENER INSTALLATION [Group 3] ........................... 1 0 0
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### Page 5

Commercial 
Airplanes
737
Service Bulletin
ALERT
SummaryNumber: 737-57A1323Original Issue: December 05, 2014
ATA System: 5711
SUBJECT: WINGS - Front Spar - Wing Front Spar Lower Chord Between WBL 114 and WBL 183
and Wing Skin Common to the Nacelle Outboard Side Load Fitting Fasteners at WBL
198.6 - Inspection
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
An operator reported that a crack was found during an inspection performed in accordance with Supplemental
Structural Inspection Document (SSID) Item W-19A on the forward leg of the left front spar lower chord at WBL
177. As a result, the front spar lower chord was removed, repaired and reinstalled. Upon additional inspection
of the repaired spar chord installation, cracks were also discovered on the lower wing skin at three fastener
holes common to the nacelle outboard side load fitting at WBL 198.6. This event occurred at 57,617 Flight Cycles
and is the first reported incident of this type. Metallurgical analysis of the chord determined that cracks initiated
at fastener holes and were propagated by operating load fatigue. The analysis found no anomalies which could
have contributed to the cracking. A Detailed Inspection/High Frequency Eddy Current (DI/HFEC) inspection of
the affected areas will determine if crack(s) exist. If not corrected, fatigue cracking of the forward leg of the left
front spar lower chord and lower wing skin common to the nacelle outboard side load fitting could adversely
affect the structural integrity of the wing.
Boeing Service Related Problem 737-SRP-57-0253 is related to this service bulletin.
Boeing Fleet Team Digest (FTD) 737 FTD 57-12002 is related to this service bulletin.
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 ChangesNoWeight and Balance Change
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ReferenceAffectedPlanning Data
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 Parts/Material
Paragraph 2.F., Special Tooling Necessary to
do this Service Bulletin
YesSpecial Tooling Required
ACTION
Refer to Paragraph 1.D., Description.
EFFECTIVITY
All 737-100, -200, -200C, -300, -400, -500 Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected
airplanes.
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.
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 7 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
114  WBL
183
FRONT SPAR LOWER
CHORD
WBL
198.6
NACELLE OUTBOARD SIDE
LOAD FITTING
WING FRONT SPAR LOWER CHORD BETWEEN
WBL 114 AND WBL 183, AND WING SKIN COMMON
FASTENERS AT WBL 198.6  TO THE NACELLE OUTBOARD SIDE LOAD FITTING  2300454
- INSPECTION
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### Page 9

Commercial 
Airplanes
737
Service Bulletin
ALERT
Number: 737-57A1323
Original Issue: December 05, 2014
ATA System: 5711
SUBJECT: WINGS - Front Spar - Wing Front Spar Lower Chord Between WBL 114 and WBL 183
and Wing Skin Common to the Nacelle Outboard Side Load Fitting Fasteners at WBL
198.6 - Inspection
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 D6-19567 Part 3 for Airplane Variable Number, Line Number, and
Serial Number data.
This service bulletin is for the airplane(s) shown below.
DESCRIPTIONCONFIGURATIONGROUP
737-100/200/200C Airplanes Line Numbers 1 - 291.-1
737-200/200C Airplanes.-2
737-300/400/500 Airplanes.-3
Airplane Models:
737-100, 737-200, 737-200C, 737-300, 737-400, 737-500
GroupVariable Number
1PA001 - PA022
1PA099
1PA231 - PA232
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GroupVariable Number
1PC001 - PC005
1PG001 - PG075
1PG199
1PG201 - PG230
1PG251 - PG255
1PG271 - PG279
1PG301 - PG314
1PG331 - PG332
1PG351 - PG356
1PG375
1PG401 - PG403
1PG431 - PG442
1PG471 - PG475
1PG501 - PG505
1PG571 - PG583
2PG584 - PG586
1PG621 - PG630
1PG651 - PG652
1PG701 - PG705
2PH001
2PH011 - PH013
2PH021 - PH024
1PH701 - PH715
1PH731 - PH732
1PH741 - PH742
2PH743
1PJ001 - PJ002
2PJ003 - PJ009
1PJ031 - PJ032
1PJ071 - PJ072
1PJ101 - PJ104
2PJ105 - PJ119
2PJ201 - PJ219
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GroupVariable Number
3PJ301 - PJ302
3PJ551 - PJ561
3PJ601 - PJ615
3PJ811
3PJ816 - PJ817
2PK026 - PK029
2PK041 - PK053
2PK061 - PK070
2PK081 - PK082
2PK091 - PK099
2PK101 - PK103
2PK111 - PK120
2PK141 - PK146
2PK201 - PK204
2PK211 - 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 - PK515
2PK519
2PK521 - PK528
2PK541 - PK565
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GroupVariable Number
2PK581
2PK591 - PK599
2PK601 - PK617
2PK621 - PK637
2PK641 - PK642
2PK661 - PK666
2PK671 - PK681
2PK691 - PK697
2PK711 - PK716
2PK731 - PK765
2PK771 - PK779
2PK801 - PK804
2PK819 - PK827
2PK830
2PK861 - PK863
2PK871 - PK874
2PK881 - PK884
2PK901 - PK938
2PK971 - PK974
2PL001 - PL028
2PL061
2PL081
2PL101 - PL113
2PL151
2PL171 - PL172
2PL201 - PL203
2PL221
2PL401 - PL417
2PL421
2PL441
2PL451 - PL456
2PL471
2PL491
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GroupVariable Number
2PL501 - PL506
2PL551 - PL562
2PL581
2PL601 - PL603
2PL611
2PL621 - PL626
2PL631 - PL632
1PL711 - PL712
1PL716
2PL717 - PL747
2PL756
2PL758
2PL761 - PL770
2PL781 - PL788
2PL793
1PL801 - PL803
2PM001 - PM006
2PM016 - PM017
2PM021 - PM023
2PM051 - PM066
2PM101 - PM119
2PM141 - PM142
2PM171
2PM181
2PM251 - PM255
2PM281 - PM283
3PM381 - PM399
3PM401 - PM417
3PM541 - PM564
2PN001 - PN002
2PN021 - PN043
2PN081 - PN086
2PN101 - PN117
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GroupVariable Number
2PN131 - PN163
2PN401 - PN420
2PN431 - PN433
2PN451 - PN456
2PN471 - PN474
2PN481
2PN491 - PN493
2PN501 - PN502
2PN511 - PN512
2PN521
3PP001 - PP054
3PP101 - PP169
3PP181 - PP199
3PP201 - PP205
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
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GroupVariable Number
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
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
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GroupVariable Number
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
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
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GroupVariable Number
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
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
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GroupVariable Number
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
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
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GroupVariable Number
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
3PW591 - PW596
3PW611 - PW622
3PW631 - PW637
3PW661 - PW662
3PW681 - PW683
3PW701 - PW702
3PW711 - PW717
3PW741 - PW742
3PW761
3PW771
3PW831
3PW851 - PW856
1PX071
1PX701
1PY001 - PY008
1PY021
2PY022
1PY031
2PY036 - PY037
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GroupVariable Number
2PY046 - PY048
2PY051 - PY053
2PY056 - PY057
2PY101 - PY103
2PY111 - PY113
2PY131 - PY135
2PY141 - PY143
2PY151 - PY154
2PY156 - PY157
2PY161 - PY162
2PY166
2PY191
2PY201
2PY221 - PY222
2PY231
2PY241 - PY244
2PY270 - PY275
2PY281
2PY286
1PY301 - PY304
1PY321 - PY323
1PY341 - PY346
1PY361 - PY362
1PY381
2PY401
2PY409 - PY411
2PY421 - PY422
2PY441
2PY451
2PY461 - PY463
2PY591 - PY595
2PY611 - PY612
2PY621
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GroupVariable Number
2PY631
2PY651
2PY671 - PY672
2PY721
2PY741
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
An operator reported that a crack was found during an inspection performed in accordance with
Supplemental Structural Inspection Document (SSID) Item W-19A on the forward leg of the left front
spar lower chord at WBL 177. As a result, the front spar lower chord was removed, repaired and
reinstalled. Upon additional inspection of the repaired spar chord installation, cracks were also discovered
on the lower wing skin at three fastener holes common to the nacelle outboard side load fitting at WBL
198.6. This event occurred at 57,617 Flight Cycles and is the first reported incident of this type.
Metallurgical analysis of the chord determined that cracks initiated at fastener holes and were propagated
by operating load fatigue. The analysis found no anomalies which could have contributed to the cracking.
A Detailed Inspection/High Frequency Eddy Current (DI/HFEC) inspection of the affected areas will
determine if crack(s) exist. If not corrected, fatigue cracking of the forward leg of the left front spar lower
chord and lower wing skin common to the nacelle outboard side load fitting could adversely affect the
structural integrity of the wing.
Boeing Service Related Problem (SRP) 737-SRP-57-0253 is related to this service bulletin.
Boeing Fleet Team Digest (FTD) 737 FTD 57-12002 is related to this service bulletin.
D. Description
This service bulletin provides instructions to do as follows:
Group 1:
1. Contact Boeing for inspection and repair instructions and do the work as instructed by Boeing.
Group 2-3:
DETAILED INSPECTION FOR CRACKS
1. Do a Detailed Inspection (DI) for any crack on the left and right wing front spar lower chord and
inspar skin between WBL 114 and WBL 183. Based on inspection findings do as follows:
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CONDITION 1: NO CRACK FOUND
a. Do repetitive (DI) for any crack on the left and right wing front spar lower chord and inspar
skin between WBL 114 and WBL 183 at intervals specified in Paragraph 1.E., Compliance,
Table 1.
b. Do corrective actions based on inspection findings.
CONDITION 2: ANY CRACK FOUND
a. Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 1: HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION FOR CRACKS
1. Do a High Frequency Eddy Current (HFEC) open hole probe inspection for any crack on the left
and right wing nacelle outboard side load fitting fastener holes common to the front spar lower
chord and skin at (WBL) 198.6. Based on inspection findings do as follows:
CONDITION 3: NO CRACK FOUND
a. Install new or serviceable fasteners on the left and right wing nacelle outboard side load fitting
fastener holes common to the front spar lower chord and skin at (WBL) 198.6.
b. Do repetitive inspection for any crack on the left and right wing at (WBL) 198.6 at intervals
specified in Paragraph 1.E., Compliance, Table 2 or Table 3.
c. Do corrective actions based on inspection findings.
CONDITION 4: ANY CRACK FOUND
a. Determine if crack is repairable and repair crack.
b. Do repetitive inspection for any crack on the left and right wing at (WBL) 198.6 at intervals
specified in Paragraph 1.E., Compliance, Table 2 or Table 3.
c. Do corrective actions based on inspection findings.
CONDITION 5: ANY CRACK FOUND AND NOT REMOVED BY MAXIMUM ALLOWABLE HOLE
SIZE
a. Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 2 - HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION THROUGH MOUSE HOLE
FOR CRACKS
1. Do a HFEC surface probe inspection through "mouse hole" for any crack in the inspar skin on the
left and right wing in areas where the skin is hidden by the nacelle outboard side load fitting and
aft back-up fitting at (WBL) 198.6. Based on inspection findings do as follows:
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CONDITION 6: NO CRACK FOUND
a. Do repetitive inspection for any crack on the left and right wing at (WBL) 198.6 at intervals
specified in Paragraph 1.E., Compliance, Table 2 or Table 3.
b. Do corrective actions based on inspection findings.
CONDITION 7: ANY CRACK FOUND
a. Contact Boeing for repair instructions and do the repair as instructed by Boeing.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1:
Affected Maintenance Zones
ZoneModel
3-4737-100, 737-200, 737-200C
Group 2:
Affected Maintenance Zones
ZoneModel
3-4737-200, 737-200C
Group 3:
Affected Maintenance Zones
ZoneModel
303, 305, 403, 405737-300, 737-400, 737-500
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.
When more than one OPTION is given for a CONDITION, 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.
Do the required actions in accordance with Paragraph 3. Accomplishment Instructions.
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Group 1:
Contact Boeing to get instructions for the inspection and repair for this service bulletin, 737-57A1323
Original issue, and do the work instructed by Boeing within 120 days of the Original issue date of this
service bulletin.
Group 2-3:
Table 1: DETAILED INSPECTION (DI) OF THE LEFT AND RIGHT WING FRONT SPAR LOWER CHORD
AND INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs later)
ActionCondition
-Within 5,000
flight cycles or
24 months after
the orignal issue
date of this ser-
vice bulletin,
whichever oc-
curs first.
Before 50,000
total flight cy-
cles.
Do PART 2, Detailed In-
spection (DI) of the left
and right wing front spar
lower chord and inspar
skin between (WBL) 114
and (WBL) 183 for
cracks.
All Airplanes
5,000 flight cycles.--Repeat PART 2, Detailed
Inspection (DI) of the left
and right wing front spar
lower chord and inspar
skin between (WBL) 114
and (WBL) 183 for
cracks.
Condition 1: No crack
found
--Before further
flight.
Contact Boeing for repair
instructions and do the
repair as instructed by
Boeing.
Condition 2: Any crack
found
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NOTE: Two options are given for the High Frequency Eddy Current (HFEC) inspection and the
corrective action for the left and right wing at WBL 198.6 for cracks. Operators must do OPTION
1 (Table 2) or OPTION 2 (Table 3).
Group 3:
Table 2: OPTION 1: HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION OF THE LEFT
AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs later)
ActionCondition
-Within 10,000
flight cycles or
48 months after
the original is-
sue date of this
service bulletin,
whichever oc-
curs first.
Before 50,000
total flight cy-
cles.
Do PART 2, High Fre-
quency Eddy Current
(HFEC) open hole inspec-
tion of the left and right
wing at (WBL) 198.6 for
cracks.
All Airplanes
--Before further
flight.
Action 1:
Do Part 2, Condition 1,
Install new or serviceable
fasteners.
Condition 3: No crack
found
AND
25,000 flight cy-
cles.
--Action 2:
Repeat PART 2, High
Frequency Eddy Current
(HFEC) open hole inspec-
tion of the left and right
wing at (WBL) 198.6 for
cracks.
(a)
--Before further
flight.
Action 1:
Do PART 3, Repair.
Condition 4: Any crack
found
AND
25,000 flight cy-
cles.
--Action 2:
Repeat PART 2, High
Frequency Eddy Current
(HFEC) open hole inspec-
tion of the left and right
wing at (WBL) 198.6 for
cracks.
(a)
--Before further
flight.
Contact Boeing for repair
instructions and do the
repair as instructed by
Boeing.
Condition 5: Any crack
found and not removed by
maximum allowable hole
size
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Group 3:
Table 2: OPTION 1: HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION OF THE LEFT
AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs later)
ActionCondition
(a) As an option, the repeat inspection may be accomplished in accordance with the repeat inspection re-
quirements outlined in Table 3 "mouse hole inspection". The repeat inspection interval must be based
on the inspection method of the most recently performed inspection. Any inspection following an "open
hole inspection" must be performed prior to 25,000 flight cycles.
NOTE: Two options are given for the High Frequency Eddy Current (HFEC) inspection and the
corrective action for the left and right wing at WBL 198.6 for cracks. Operators must do OPTION
1 (Table 2) or OPTION 2 (Table 3).
Group 3:
Table 3: OPTION 2: HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION THROUGH MOUSE HOLE
OF THE LEFT AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
Repeat Inter-
val (Not to Ex-
ceed)
Compliance Time (Whichever Occurs Latest)ActionCondition
-Within 10,000
flight cycles af-
ter last (SSID)
W-19B inspec-
tion
Within 10,000
flight cycles or
48 months after
the original is-
sue date of this
service bulletin,
whichever oc-
curs first
Before 50,000
total flight cy-
cles.
Do PART 2, High Fre-
quency Eddy Current
(HFEC) inspection
through mouse hole of
the left and right wing at
(WBL) 198.6 for cracks.
All Airplanes
10,000 flight
cycles.
---Repeat PART 2, High
Frequency Eddy Current
(HFEC) inspection
through mouse hole of
the left and right wing at
(WBL) 198.6 for cracks.
Condition 6:
No crack found
(a)
---Before further
flight.
Contact Boeing for repair
instructions and do the
repair as instructed by
Boeing.
Condition 7:
Any crack
found
(a) As an option, the repeat inspection may be accomplished in accordance with the repeat inspection re-
quirements outlined in Table 2 "open hole inspection". The repeat inspection interval must be based on
the inspection method of the most recently performed inspection. Any inspection following a "mouse hole
inspection" must be performed prior to 10,000 flight cycles.
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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.
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 table below shows an estimate of the task hours necessary to do this inspection 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:
No manpower information given.
Group 2:
DETAILED INSPECTION (DI) OF THE LEFT AND RIGHT WING FRONT SPAR LOWER CHORD
AND INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
Elapsed HoursTask HoursNumber of PersonsTask
0.501.002Open Access
2.002.001FIGURE 1
2.002.001FIGURE 2
1.002.002Close Access
5.507.00TOTAL FOR EACH AIRPLANE
(a)
(a) Inspection hours given are for each airplane.
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Group 3:
DETAILED INSPECTION (DI) OF THE LEFT AND RIGHT WING FRONT SPAR LOWER CHORD
AND INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
Elapsed HoursTask HoursNumber of PersonsTask
1.002.002Open Access
2.002.001FIGURE 3
2.002.001FIGURE 4
1.503.002Close Access
6.509.00TOTAL FOR EACH AIRPLANE
(a)
(a) Inspection hours given are for each airplane.
Group 3:
OPTION 1: HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION OF THE
LEFT AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
Elapsed HoursTask HoursNumber of PersonsTask
4.5036.008Open Access
1.251.251FIGURE 5
1.251.251FIGURE 6
0.500.501FIGURE 9
0.500.501FIGURE 10
0.750.751FIGURE 11
0.750.751FIGURE 12
1.001.001FIGURE 13
1.001.001FIGURE 14
1.001.001FIGURE 15
1.001.001FIGURE 16
1.001.001FIGURE 17
1.001.001FIGURE 18
4.7538.008Close Access
20.2585.00TOTAL FOR EACH AIRPLANE
(a) (b)
(a) Inspection hours given are for each airplane.
(b) Maximum task hours are given, actual hours are to be determined by the op-
erator based on inspection results.
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Group 3:
OPTION 2: HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION THROUGH MOUSE
HOLE OF THE LEFT AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
Elapsed HoursTask HoursNumber of PersonsTask
3.0012.004Open Access
0.750.751FIGURE 7
0.750.751FIGURE 8
3.006.002Close Access
7.0019.50TOTAL FOR EACH AIRPLANE
(a)
(a) Inspection hours given are for each airplane.
H. Weight and Balance Changes
None.
I. Electrical Load Data
None.
J. References
1. Existing Data:
a. Boeing Service Related Problem (SRP) 737-SRP-57-0253
b. Service Bulletin Index D6-19567
c. Standard Overhaul Practices Manual (SOPM) 20-50-19
d. 737/300/400/500 Supplemental Structural Inspection Document (SSID) W-19B, WBL 198.6
e. 737 Fleet Team Digest (FTD) 57-12002
f. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Procedure 16, Part 6, 57-10-24
g. 737-200 Aircraft Maintenance Manual (AMM) 24-22-00, 27-81-00, 29-11-00
h. 737-200 Maintenance Planning Data (MPD) Chapter 1, Section 1-4
i. 737-300/400/500 Aircraft Maintenance Manual (AMM) 24-22-00, 27-81-00, 28-23-00, 29-15-00,
51-31-00, 71-00-02
j. 737-300/400/500 Maintenance Planning Data (MPD) Section 4
k. 737-300/400/500 Structural Repair Manual (SRM) 51-40-04, 51-40-09
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2. Data Supplied with this Service Bulletin:
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin:
TitleDrawing Number
SUPPORT INSTL - ENGINE NACELLE, WING65C25203
FRONT SPAR INSTALLATION - WING65-45320
The table above lists applicable drawings used to prepare this service bulletin. The drawings are
not necessary to make the specified changes, and are not supplied with this service bulletin. The
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 but no new DTIs are necessary.
L. Interchangeability and Intermixability of Parts
None.
M. Software Accomplishment Summary
None.
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2.    MATERIAL INFORMATION
A. Material - Price and Availability
The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each
Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin
does not show the Boeing price and supply data.
B. Industry Support Information
Boeing warranty remedies are not available for the inspection or repair given in this service bulletin.
C. Parts Necessary for Each Airplane
1. Kits/Parts
None.
2. Parts and Materials Supplied by the Operator
The following parts or materials are necessary to do the change in this service bulletin. Parts and
materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine
operator part and material supply to make sure all necessary parts and materials are available.
a. Group 1-2:
None.
b. Group 3:
OPTION 1, CONDITION 3
NotesNameQTYPart Number / Specifica-
tion
(a)BOLT4BACB30US9K31M
BOLT4BACB30US9K32M
WASHER8BACW10BP9CD
WASHER8BACW10BP9DP
NUT8BACN10HR9CD
-SEALANT50 ozBMS 5-45
(a) Refer to 737 Structural Repair Manual Chapter 51 for alternate fasteners.
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c. Group 3:
OPTION 1, CONDITION 4
NotesNameQTYPart Number / Specifica-
tion
(a)BOLTARBACB30US10K31M
BOLTARBACB30US10K32M
BOLTARBACB30US10K31MX
BOLTARBACB30US10K32MX
BOLTARBACB30US10K31MY
BOLTARBACB30US10K32MY
BOLTARBACB30US9K31MX
BOLTARBACB30US9K32MX
WASHERARBACW10BP10CD
WASHERARBACW10BP10DP
WASHERARBACW10BP101CD
WASHERARBACW10BP101DP
WASHERARBACW10BP102CD
WASHERARBACW10BP102DP
WASHERARBACW10BP91CD
WASHERARBACW10BP91DP
NUTARBACN10HR9CD
NUTARBACN10HR10CD
-SEALANT50 ozBMS 5-45
(a) Refer to 737 Structural Repair Manual Chapter 51 for alternate fasteners. "AR" is "As Required"
quantity.
d. Group 3:
OPTION 2, CONDITIONS 6 AND 7
None.
3. Parts Modified and Reidentified
None.
4. Parts Removed and Not Replaced
None.
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D. Parts Necessary to Change Spares
None
E. Special Tooling - Price and Availability
Group 1-2:
1. None.
Group 3:
Option 1, Condition 3
1. None.
Group 3:
Option 1, Condition 4
1. The 737-300/400/500 SRM 51-40-09 gives data about cold working tools and sleeves necessary
to do the work given in this service bulletin. These tools are available from industry sources.
West Coast Industries, Inc.
14900 Whitman Avenue North
Seattle, WA 98133-6532 USA
Phone Number (206) 365-7513
Fax (206) 365-7483
Group 3:
Option 2, Conditions 6 and 7
1. None.
F. Special Tooling Necessary to do this Service Bulletin
Group 1-2:
1. None.
Group 3:
Option 1, Condition 3
1. None.
Group 3:
Option 1, Condition 4
1. Cold working tools are necessary to do the change given in this service bulletin. To get the cold
working tools, refer to Paragraph 2.E., Special Tooling - Price and Availability.
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Group 3:
Option 2, Conditions 6 and 7
1. None.
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3.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL
PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL,
METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE
DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR
OTHER ELECTRICAL DAMAGE.
NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for
definition of the acronyms.
2. Obey all of the warnings and cautions given in the specified manual sections.
3. Unless shown differently, these dimensions and tolerances are used:
– Linear dimensions are in inches
– Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus
or minus 0.03 inch
– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch
– Angular tolerance is plus or minus 2 degrees
– Hole dimensions for standard solid rivets and fasteners are in Structural Repair
Manual (SRM) Chapter 51
– Torque Values:
— Values for structural fasteners are given in 737 Structural Repair Manual,
Chapter 51.
— Values for engine maintenance tasks are included in Chapter 70 of 737
Airplane Maintenance Manual (AMM).
— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
4. Use the approved fastener, process and material substitutions in accordance with
SRM Chapter 51.
5. If the length of any fastener specified in this service bulletin does not meet installation
standards given in SRM Chapter 51, then a fastener of the same specification, or
an approved substitute, with a length which meets the installation standards given
in SRM Chapter 51 may be used. In addition, washers may be installed for fastener
grip length in accordance with SRM Chapter 51.
6. A Detailed Inspection is defined as: An intensive examination of a specific item,
installation, or assembly to detect damage, failure, or irregularity. Available lighting
is normally supplemented with a direct source of good lighting at an intensity deemed
appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be
necessary. Surface cleaning and elaborate procedures may be required.
7. These work instructions refer to procedures included in other Boeing documents.
When the words "refer to" are used and the operator has an accepted alternative
procedure, the accepted alternative procedure can be used. When the words "in
accordance with" are included in the instruction, the procedure in the Boeing document
must be used.
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8. The instructions in Paragraph 3.B., Work Instructions and the figures can include
operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated
Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing
Index contain data on versions of the tools or test equipment that you can use. It is
permitted to use replaced tools. It is not permitted to use superseded tools.
9. If it is necessary to remove more parts for access, you can remove those parts. If
you can get access without removing identified parts, it is not necessary to remove
all of the identified parts. Jacking and shoring limitations must be observed.
10. Where the work instructions include installation of a kept part, a new or serviceable
part with the same part number can be installed as an alternative to the kept part.
11. This service bulletin includes functional test procedures for the systems changed by
this service bulletin. More functional tests can possibly be necessary in accordance
with standard maintenance practices because of interruption to other airplane systems.
12. Use of colors in Figures is based on guidance from the ATA e-Business Program
(ATA) iSpec 2200.
13. When more than one OPTION is given for a CONDITION, 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.
14. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS
are in Paragraph 1.E., Compliance.
15. The CONDITIONS, ACTIONS and OPTIONS shown apply to each fastener location
independently.
16. Some steps in the Work Instructions are identified as Required for Compliance (RC).
If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps
identified as RC must be done to comply with the AD. Alternative procedures for
steps not identified with RC can be used if the RC steps can still be done as specified,
and the airplane can be put back in a serviceable condition. An Alternative Method
of Compliance (AMOC) is not necessary for deviations to steps that are not identified
as RC.
B. WORK INSTRUCTIONS
Group 1:
1. RC - Contact Boeing to get instructions for the inspection and repair for this service bulletin, and
do the work instructed by Boeing.
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Group 2-3:
1. PART 1: ACCESS
ACCESS FOR DETAILED INSPECTION (DI) OF THE LEFT AND RIGHT WING FRONT SPAR
LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
a. Group 2:
Extend Krueger flaps. Refer to 737-200 AMM 27-81-00 as an accepted procedure.
b. Group 3:
Extend Krueger flaps. Refer to 737-300/400/500 AMM 27-81-00 as an accepted procedure.
c. Group 2:
Remove electrical power from the airplane. Refer to 737-200 AMM 24-22-00 as an accepted.
procedure.
d. Group 3:
Remove electrical power from the airplane. Refer to 737-300/400/500 AMM 24-22-00 as an
accepted. procedure.
e. Group 2:
Depressurize and safety hydraulic systems. Refer to 737-200 AMM 29-11-00 as an accepted
procedure.
f. Group 3:
Depressurize and safety hydraulic systems. Refer to 737-300/400/500 AMM 29-15-00 as an
accepted procedure.
g. Group 2:
Gain access to the area of inspection by removing access panels 6301L and 6401R . Refer
to 737-200 MPD Chapter 1, Section 1-4.
h. Group 3:
Gain access to the area of inspection by removing access panels 6304L, 6404R, 6305L and
6405R. Refer to 737-300/400/500 MPD Section 4.
Group 3:
OPTION 1: ACCESS FOR HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE
INSPECTION OF THE LEFT AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
a. Defuel and purge wing fuel tanks and prepare for entry. Refer to 737-300/400/500 AMM
28-23-00 as an accepted procedure.
b. Remove number 1 and 2 engines. Refer to 737-300/400/500 AMM 71-00-02 as an accepted
procedure.
c. Gain access to the area of inspection by removing access panels 7204L, 7404R, 7205L,
7405R, 7224L and 7424R. Refer to 737-300/400/500 MPD Section 4.
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Group 3:
OPTION 2: ACCESS FOR HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION
THROUGH MOUSE HOLE OF THE LEFT AND RIGHT WING AT (WBL) 198.6 FOR CRACKS
a. Defuel and purge wing fuel tanks and prepare for entry. Refer to 737-300/400/500 AMM
28-23-00 as an accepted procedure.
b. Gain access to the area of inspection by removing access panels 7204L, 7404R, 7205L,
7405R, 7224L and 7424R. Refer to 737-300/400/500 MPD Section 4.
2. PART 2: INSPECTION
Group 2:
DETAILED INSPECTION (DI) OF THE LEFT WING FRONT SPAR LOWER CHORD AND INSPAR
SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
a. RC - Do a Detailed Inspection (DI) for any crack on the left wing front spar lower chord and
inspar skin between WBL 114 and WBL 183 in accordance with FIGURE 1.
CONDITION 1: NO CRACK FOUND
(1) Do PART 4, Restoration.
(2) RC - Repeat PART 2, DI for any crack on the left wing front spar lower chord and inspar
skin between WBL 114 and WBL 183 at intervals specified in Paragraph 1.E., Compliance,
Table 1.
CONDITION 2: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
DETAILED INSPECTION (DI) OF THE LEFT WING FRONT SPAR LOWER CHORD AND INSPAR
SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
a. RC - Do a Detailed Inspection (DI) for any crack on the left wing front spar lower chord and
inspar skin between WBL 114 and WBL 183 in accordance with FIGURE 3.
CONDITION 1: NO CRACK FOUND
(1) Do PART 4, Restoration.
(2) RC - Repeat PART 2, DI for any crack on the left wing front spar lower chord and inspar
skin between WBL 114 and WBL 183 at intervals specified in Paragraph 1.E., Compliance,
Table 1.
CONDITION 2: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
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Group 2:
DETAILED INSPECTION (DI) OF THE RIGHT WING FRONT SPAR LOWER CHORD AND
INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
a. RC - Do a Detailed Inspection (DI) for any crack on the right wing front spar lower chord and
inspar skin between WBL 114 and WBL 183 in accordance with FIGURE 2.
CONDITION 1: NO CRACK FOUND
(1) Do PART 4, Restoration.
(2) RC - Repeat PART 2, DI for any crack on the right wing front spar lower chord and inspar
skin between WBL 114 and WBL 183 at intervals specified in Paragraph 1.E., Compliance,
Table 1.
CONDITION 2: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
DETAILED INSPECTION (DI) OF THE RIGHT WING FRONT SPAR LOWER CHORD AND
INSPAR SKIN BETWEEN (WBL) 114 AND (WBL) 183 FOR CRACKS
a. RC - Do a Detailed Inspection (DI) for any crack on the right wing front spar lower chord and
inspar skin between WBL 114 and WBL 183 in accordance with FIGURE 4.
CONDITION 1: NO CRACK FOUND
(1) Do PART 4, Restoration.
(2) RC - Repeat PART 2, DI for any crack on the right wing front spar lower chord and inspar
skin between WBL 114 and WBL 183 at intervals specified in Paragraph 1.E., Compliance,
Table 1.
CONDITION 2: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 1 - HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION OF THE
LEFT WING FOR CRACKS
CAUTION: IT IS RECOMMENDED THAT NOT MORE THAN TWO NACELLE OUTBOARD
SIDE LOAD FITTING FASTENERS BE REMOVED AT A TIME. IF YOU REMOVE
MORE THAN TWO FASTENERS AT A TIME YOU MAY NOT BE ABLE TO
MAINTAIN FITTING TO WING SURFACE JOINT CLAMP-UP. REAMING THE
HOLES WITHOUT PROPER CLAMP-UP MAY DAMAGE THE HOLES.
a. RC- Remove nacelle outboard side load fitting fasteners and do a High Frequency Eddy
Current (HFEC) open hole probe inspection for any crack in accordance with FIGURE 5.
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CONDITION 3: NO CRACK FOUND
(1) RC - Install new or serviceable fasteners in accordance with FIGURE 9.
(2) Do PART 4 - Restoration.
(3) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the left
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 4: ANY CRACK FOUND
(1) RC - Do the repair in accordance with PART 3.
(2) Do PART 4 - Restoration.
(3) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the left
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 5: ANY CRACK FOUND AND NOT REMOVED BY MAXIMUM ALLOWABLE
HOLE SIZE
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 1 - HIGH FREQUENCY EDDY CURRENT (HFEC) OPEN HOLE INSPECTION OF THE
RIGHT WING FOR CRACKS
CAUTION: IT IS RECOMMENDED THAT NOT MORE THAN TWO NACELLE OUTBOARD
SIDE LOAD FITTING FASTENERS BE REMOVED AT A TIME. IF YOU REMOVE
MORE THAN TWO FASTENERS AT A TIME YOU MAY NOT BE ABLE TO
MAINTAIN FITTING TO WING SURFACE JOINT CLAMP-UP. REAMING THE
HOLES WITHOUT PROPER CLAMP-UP MAY DAMAGE THE HOLES.
a. RC - Remove nacelle outboard side load fitting fasteners and do a High Frequency Eddy
Current (HFEC) open hole probe inspection for any crack in accordance with FIGURE 6.
CONDITION 3: NO CRACK FOUND
(1) RC - Install new or serviceable fasteners in accordance with FIGURE 10.
(2) Do PART 4 - Restoration.
(3) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the right
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 4: ANY CRACK FOUND
(1) RC - Do the repair in accordance with PART 3.
(2) Do PART 4 - Restoration.
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(3) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the right
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 5: ANY CRACK FOUND AND NOT REMOVED BY MAXIMUM ALLOWABLE
HOLE SIZE
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 2 - HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION THROUGH MOUSE
HOLE OF THE LEFT WING FOR CRACKS
a. RC - Do a HFEC surface probe inspection through "mouse hole" for any crack in accordance
with FIGURE 7.
CONDITION 6: NO CRACK FOUND
(1) Do PART 4 - Restoration.
(2) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the left
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 7: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
Group 3:
OPTION 2 - HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION THROUGH MOUSE
HOLE OF THE RIGHT WING FOR CRACKS
a. RC - Do a HFEC surface probe inspection through "mouse hole" for any crack in accordance
with FIGURE 8.
CONDITION 6: NO CRACK FOUND
(1) Do PART 4 - Restoration.
(2) RC - Repeat PART 2, Option 1 or Option 2 (HFEC) inspection for any crack on the right
wing at (WBL) 198.6 at intervals specified in Paragraph 1.E., Compliance, Table 2 or
Table 3.
CONDITION 7: ANY CRACK FOUND
(1) RC - Contact Boeing for repair instructions and do the repair as instructed by Boeing.
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3. PART 3: REPAIR
Group 3:
OPTION 1, CONDITION 4: ANY CRACK FOUND - LEFT WING
a. RC - Ream any cracked hole incrementally to remove crack. Begin with the smallest hole
diameter size first in accordance with the table below.
MORE DATAFASTENER INSTALLATIONFINAL INSPECTION HOLE SIZE
(a) (b)FIGURE 110.5776/0.5786 INCH DIAMETER
FIGURE 130.5970/0.6000 INCH DIAMETER
FIGURE 150.6130/0.6160 INCH DIAMETER
(a) (b) (c)FIGURE 170.6310/0.6340 INCH DIAMETER MAXIMUM
(a) To ensure crack has been removed, do HFEC open hole probe inspection for cracks after
ream inspection hole size in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure
16, dated November 15, 2012, or later Boeing approved revisions that are published on My-
BoeingFleet.
(b) If no crack is found, install oversized fastener in accordance with FIGURE 11 or FIGURE 13
or FIGURE 15 or FIGURE 17.
(c) 0.6310/0.6340 is the maximum hole size allowable for crack removal. If any crack is found,
do the actions specified under PART 2, Group 3, Option 1, Condition 5.
Group 3:
OPTION 1, CONDITION 4: ANY CRACK FOUND - RIGHT WING
a. RC - Ream any cracked hole incrementally to remove crack. Begin with the smallest hole size
diameter first in accordance with the table below.
MORE DATAFASTENER INSTALLATIONFINAL INSPECTION HOLE SIZE
(a) (b)FIGURE 120.5776/0.5786 INCH DIAMETER
FIGURE 140.5970/0.6000 INCH DIAMETER
FIGURE 160.6130/0.6160 INCH DIAMETER
(a) (b) (c)FIGURE 180.6310/0.6340 INCH DIAMETER MAXIMUM
(a) To ensure crack has been removed, do HFEC open hole probe inspection for cracks after
ream inspection hole size in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure
16, dated November 15, 2012, or later Boeing approved revisions that are published on My-
BoeingFleet.
(b) If no crack is found, install oversized fastener in accordance with FIGURE 12 or FIGURE 14
or FIGURE 16 or FIGURE 18.
(c) 0.6310/0.6340 is the maximum hole size allowable for crack removal. If any crack is found,
do the actions specified under PART 2, Group 3, Option 1, Condition 5.
4. PART 4: RESTORATION
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Group 2-3:
CLOSE ACCESS AFTER COMPLETION OF THE DETAILED INSPECTION (DI) OF THE LEFT
AND RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114
AND (WBL) 183 FOR CRACKS
a. Group 2:
Reinstall access panels 6301L and 6401R . Refer to 737-200 MPD Chapter 1, Section 1-4.
b. Group 3:
Reinstall access panels 6304L, 6404R, 6305L and 6405R. Refer to 737-300/400/500 MPD
Section 4.
c. Group 2:
Apply electrical power to the airplane. Refer to 737-200 AMM 24-22-00 as an accepted
procedure.
d. Group 3:
Apply electrical power to the airplane. Refer to 737-300/400/500 AMM 24-22-00 as an accepted
procedure.
e. Group 2:
Pressurize hydraulic systems. Refer to 737-200 AMM 29-11-00 as an accepted procedure.
f. Group 3:
Pressurize hydraulic systems. Refer to 737-300/400/500 AMM 29-15-00 as an accepted
procedure.
g. Group 2:
Retract Krueger flaps. Refer to 737-200 AMM 27-81-00 as an accepted procedure.
h. Group 3:
Retract Krueger flaps. Refer to 737-300/400/500 AMM 27-81-00 as an accepted procedure.
Group 3:
OPTION 1: CLOSE ACCESS AFTER COMPLETION OF THE HIGH FREQUENCY EDDY
CURRENT (HFEC) OPEN HOLE INSPECTION OF THE LEFT AND RIGHT WING AT (WBL)
198.6 FOR CRACKS
a. Reinstall number 1 and 2 engines. Refer to 737-300/400/500 AMM 71-00-02 as an accepted
procedure.
b. Reinstall access panels 7204L, 7404R, 7205L, 7405R, 7224L and 7424R. Refer to
737-300/400/500 MPD Section 4.
c. Refuel wing fuel tanks. Refer to 737-300/400/500 AMM 28-23-00 as an accepted procedure.
Group 3:
OPTION 2: CLOSE ACCESS AFTER COMPLETION OF THE HIGH FREQUENCY EDDY
CURRENT (HFEC) MOUSE HOLE INSPECTION OF THE LEFT AND RIGHT WING AT (WBL)
198.6 FOR CRACKS
a. Reinstall access panels 7204L, 7404R, 7205L, 7405R, 7224L and 7424R. Refer to
737-300/400/500 MPD Section 4.
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### Page 44

b. Refuel wing fuel tanks. Refer to 737-300/400/500 AMM 28-23-00 as an accepted procedure.
5. Put airplane back to a serviceable condition.
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### Page 45 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
This Figure applies only to: Group 2.
FRONT SPAR
WBL
114
WBL
150
FRONT SPAR /
LOWER CHORD
WBL
183
2300788
FIGURE 1: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 1 OF 4)
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### Page 46 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
114
FRONT SPAR
WBL
INED  150
A.
(TYPICAL)
LOWER
WING SKIN
WBL
150
LOWER CHORD  FRONT SPAR  - FRONT SPAR
FRONT SPAR
LOWER CHORD
WBL
114  LOWER
WING SKIN
4.50
4.00
- FRONT SPAR
FWD
.4.50
FRONT SPAR  4.00
LOWER CHORD
INSPECTION AREA  (TYPICAL)  A-A  LOWER  WING SKIN  2300828
FIGURE 1: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 2 OF 4)
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### Page 47 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
150
FRONT SPAR
WBL
183
B
TYPICAL
B
LOWER
WING SKIN
LOWER CHORD  FRONT SPAR  WBL  183
• FRONT SPAR
FRONT SPAR
LOWER CHORD
WBL
150  • LOWER
WING SKIN
4.50
4.00
FRONT SPAR
• 4.50
FRONT SPAR  4.00
LOWER CHORD
TYPICAL  LOWER
INSPECTION AREA  B-B  WING SKIN
FIGURE 1: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 3 OF 4)
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### Page 48

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
(a) (b)--FRONT SPAR LOWER
CHORD WBL 114 TO
WBL 150
Inspect1
(a) (b)--INSPAR SKIN WBL
114 TO WBL 150
Inspect2
(a) (b)--FRONT SPAR LOWER
CHORD WBL 150 TO
WBL 183
Inspect3
(a) (b)--INSPAR SKIN WBL
150 TO WBL 183
Inspect4
(a) Do Detailed Inspection (DI) for any crack.
(b) Removal of attached structure obscuring inspection areas is not required to perform the DI.
FIGURE 1: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 4 OF 4)
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### Page 49 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
This Figure applies only to: Group 2.
FRONT SPAR
WBL
114
WBL
150
\ FRONT SPAR
LOWER CHORD
WBL
183
2300847
FIGURE 2: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 1 OF 4)
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### Page 50 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
114
FRONT SPAR
WBL
150
ERND
(TYPICAL)
LOWER
WING SKIN
WBL
150
FRONT SPAR  FRONT SPAR  LOWER CHORD
FRONT SPAR
LOWER CHORD
WBL
LOWER  114
WING SKIN
4.50
FRONT SPAR  4.00
,4.50
4.00  FRONT SPAR
LOWER CHORD  2300852
LOWER  (TYPICAL)  INSPECTION AREA
WING SKIN  A-A
FIGURE 2: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 2 OF 4)
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### Page 51 (OCR)

BOEING SERVICE BULLETIN 737-57A1323C
ALERT  ALERT
WBL
150
FRONT SPAR
WBL
183
TYPICAL
LOWER  → B
WING SKIN
WBL
183  FRONT SPAR
LOWER CHORD
FRONT SPAR
FRONT SPAR
LOWER CHORD
WBL
LOWER  150
WING SKIN
4.50
4.00
FRONT SPAR
FWD
4.50  FRONT SPAR
4.00  LOWER CHORD
LOWER  TYPICAL  INSPECTION AREA  2305791
WING SKIN  B-B
FIGURE 2: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 3 OF 4)
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### Page 52

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
(a) (b)--FRONT SPAR LOWER
CHORD WBL 114 TO
WBL 150
Inspect1
(a) (b)--INSPAR SKIN WBL
114 TO WBL 150
Inspect2
(a) (b)--FRONT SPAR LOWER
CHORD WBL 150 TO
WBL 183
Inspect3
(a) (b)--INSPAR SKIN WBL
150 TO WBL 183
Inspect4
(a) Do Detailed Inspection (DI) for any crack.
(b) Removal of attached structure obscuring inspection areas is not required to perform the DI.
FIGURE 2: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 4 OF 4)
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### Page 53 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
This Figure applies only to: Group 3.
FRONT SPAR
WBL
114
WBL
150
FRONT SPAR /
LOWER CHORD
WBL
183
2308995
FIGURE 3: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 1 OF 4)
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### Page 54 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
114
FRONT SPAR
WBL
INED  150
A.
(TYPICAL)
LOWER
WING SKIN
WBL
150
LOWER CHORD  FRONT SPAR  - FRONT SPAR
FRONT SPAR
LOWER CHORD
WBL
114  LOWER
WING SKIN
4.50
4.00
- FRONT SPAR
FWD
4.50
FRONT SPAR  4.00
LOWER CHORD
INSPECTION AREA  (TYPICAL)  A-A  LOWER  WING SKIN
FIGURE 3: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 2 OF 4)
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### Page 55 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
150
FRONT SPAR
WBL
183
TYPICAL
B  LOWER
WING SKIN
WBL
183
FRONT SPAR
LOWER CHORD  FRONT SPAR
FRONT SPAR
LOWER CHORD
WBL
150  LOWER
WING SKIN
4.50
4.00
FRONT SPAR
- 4.50
FRONT SPAR  4.00
LOWER CHORD  TYPICAL  LOWER  2308975
INSPECTION AREA  B-B  WING SKIN
FIGURE 3: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 3 OF 4)
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Export Controlled ECCN: 9E991 - BOEING  737-57A1323
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Work - See page 1 for details.  55 of 102

### Page 56

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
(a) (b)--FRONT SPAR LOWER
CHORD WBL 114 TO
WBL 150
Inspect1
(a) (b)--INSPAR SKIN WBL
114 TO WBL 150
Inspect2
(a) (b)--FRONT SPAR LOWER
CHORD WBL 150 TO
WBL 183
Inspect3
(a) (b)--INSPAR SKIN WBL
150 TO WBL 183
Inspect4
(a) Do Detailed Inspection (DI) for any crack.
(b) Removal of attached structure obscuring inspection areas is not required to perform the DI.
FIGURE 3: LEFT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: December 05, 2014
737-57A1323
56 of 102
BOEING SERVICE BULLETIN 737-57A1323
ALERTALERT

### Page 57 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
This Figure applies only to: Group 3.
FRONT SPAR
WBL
114
WBL
150
\ FRONT SPAR
LOWER CHORD
WBL
183
2308997
FIGURE 4: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 1 OF 4)
Original Issue: December 05, 2014
Export Controlled ECCN: 9E991 - BOEING  737-57A1323
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.  57 of 102

### Page 58 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
114
FRONT SPAR
WBL
150
(TYPICAL)
LOWER
WING SKIN
WBL
150
FRONT SPAR
FRONT SPAR  LOWER CHORD
FRONT SPAR
LOWER CHORD
WBL
LOWER  114
WING SKIN
4.50
4.00
FRONT SPAR
FWD
,4.50
4.00  FRONT SPAR
LOWER CHORD  2308998
LOWER  (TYPICAL)  INSPECTION AREA
WING SKIN  A-A
FIGURE 4: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 2 OF 4)
Original Issue: December 05, 2014
PROPRIETARY - Copyright © Unpublished  Export Controlled ECCN: 9E991 - BOEING  737-57A1323
Work - See page 1 for details.  58 of 102

### Page 59 (OCR)

BOEING SERVICE BULLETIN 737-57A1323
ALERT  ALERT
WBL
150
FRONT SPAR
WBL
183
B  TINED
LEND
TYPICAL
LOWER
WING SKIN  B
WBL
183
FRONT SPAR
FRONT SPAR  LOWER CHORD
FRONT SPAR
LOWER CHORD
WBL
LOWER  150
WING SKIN
4.50
4.00
FRONT SPAR
FWD
_4.50.
4.00  FRONT SPAR
LOWER CHORD  2308999
LOWER  TYPICAL  INSPECTION AREA
WING SKIN  B-B
FIGURE 4: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 3 OF 4)
Original Issue: December 05, 2014
Export Controlled ECCN: 9E991 - BOEING  737-57A1323
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.  59 of 102

### Page 60

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
More DataQtyIdentificationNameTaskStep
(a) (b)--FRONT SPAR LOWER
CHORD WBL 114 TO
WBL 150
Inspect1
(a) (b)--INSPAR SKIN WBL
114 TO WBL 150
Inspect2
(a) (b)--FRONT SPAR LOWER
CHORD WBL 150 TO
WBL 183
Inspect3
(a) (b)--INSPAR SKIN WBL
150 TO WBL 183
Inspect4
(a) Do Detailed Inspection (DI) for any crack.
(b) Removal of attached structure obscuring inspection areas is not required to perform the DI.
FIGURE 4: RIGHT WING FRONT SPAR LOWER CHORD AND INSPAR SKIN BETWEEN (WBL) 114 AND
(WBL) 183 - DETAILED INSPECTION (DI)
(SHEET 4 OF 4)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: December 05, 2014
737-57A1323
60 of 102
BOEING SERVICE BULLETIN 737-57A1323
ALERTALERT

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