# Boeing Alert Service Bulletin 747-53A2494: Revision 1

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- Document: [Boeing Alert Service Bulletin 747-53A2494](https://openairdocs.org/service-documents/boeing/747-53a2494.md)
- Title as filed: U.S. DOT/FAA - SB-747-53A2494-01
- Pages: 48
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## Text

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### Page 1

Commercial 
Airplanes
747
Service Bulletin
ALERT
Number: 747-53A2494
Original Issue: September 18, 2003
Revision 1: January 09, 2015
ATA System: 5312
SUBJECT: FUSELAGE - Section 46 - Body Station 2231 Frame Inner Chord Crack Inspection and
Repair
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 © 2003 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Unpublished Work.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: September 18, 2003
747-53A2494Revision 1: January 09, 2015
1 of 48
4.0

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Table of Contents
Revision Transmittal Sheet ............................................ 5
Summary ...................................................... 7
1. PLANNING INFORMATION ........................................ 1 1
A. Effectivity ............................................... 1 1
1. Airplanes ............................................ 1 1
2. Spares Affected ........................................ 2 0
B. Concurrent Requirements ...................................... 2 0
C. Reason ................................................ 2 0
D. Description .............................................. 2 1
E. Compliance .............................................. 2 2
F. Approval ............................................... 2 4
G. Manpower .............................................. 2 5
H. Weight and Balance Changes .................................... 2 7
I. Electrical Load Data ......................................... 2 7
J. References .............................................. 2 7
1. Existing Data: ......................................... 2 7
2. Data Supplied with this Service Bulletin: ........................... 2 7
3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 2 7
K. Publications Affected ........................................ 2 7
L. Interchangeability and Intermixability of Parts ........................... 2 8
M. Software Accomplishment Summary ................................ 2 8
2. MATERIAL INFORMATION ........................................ 2 9
A. Material - Price and Availability ................................... 2 9
B. Industry Support Information .................................... 2 9
C. Parts Necessary for Each Airplane ................................. 2 9
1. Kits/Parts: ........................................... 2 9
2. Parts and Materials Supplied by the Operator: ........................ 2 9
3. Parts Modified and Reidentified: ............................... 2 9
4. Parts Removed and Not Replaced: .............................. 2 9
D. Parts Necessary to Change Spares ................................. 2 9
E. Special Tooling - Price and Availability ............................... 2 9
F. Special Tooling Necessary to do this Service Bulletin ....................... 2 9
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 1
A. GENERAL INFORMATION ..................................... 3 1
B. WORK INSTRUCTIONS ....................................... 3 2
FIGURE 1: THIS FIGURE IS DELETED .................................. 3 5
FIGURE 2: ACCESS / RESTORATION FOR CONFIGURATION WITH PASSENGERS IN THE AFT BODY
[Group 1, 3] ........................................... 3 6
FIGURE 3: ACCESS / RESTORATION FOR CONFIGURATION WITH CARGO IN THE AFT BODY [Group
2 ,  4 ]  ............................................... 3 8
FIGURE 4: INSPECTION [Group 1-4, Configuration 1] .......................... 4 0
FIGURE 5: HFEC INSPECTION ...................................... 4 3
APPENDIX A: LOGIC DIAGRAM [Group 1-4, Configuration 1] ........................ 4 6
APPENDIX B: LOGIC DIAGRAM [Group 1-4, Configuration 2] ........................ 4 8
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ALERTALERT
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Commercial 
Airplanes
747
Service Bulletin
ALERT
Revision Transmittal SheetNumber: 747-53A2494Original Issue: September 18, 2003
Revision 1: January 09, 2015
ATA System: 5312
SUBJECT: FUSELAGE - Section 46 - Body Station 2231 Frame Inner Chord Crack Inspection and
Repair
This revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
More work is necessary on the airplane(s) changed or inspected in accordance with the original issue of this
service bulletin. Do HFEC initial inspection and repeat inspections in accordance with this revision.
Airplanes RT631-RT632, RT743 and RT876, which have been modified to the 747 Large Cargo Freighter (LCF)
configuration, have been removed from the effectivity of this service bulletin.
Federal Aviation Administration (FAA) Airworthiness Directive AD 2005-01-09 is related to this service bulletin.
REASON FOR REVISION
This revision is sent to include HFEC initial inspection and repeat inspections for the Body Station (STA) 2231
Frame Inner Chord. This revision is also sent to include new SRM repairs. The inspections in this service bulletin
are similar to the inspections in Boeing Service Bulletin 747-53A2450 R07, which begin before 16,000 total flight
cycles.
These sections were changed:
1. In the Background paragraph in the Summary section, changed to include new work, SRP references
and planning data table.
2. In the Action paragraph in the Summary section, changed to include new work.
3. In the Effectivity paragraph in the Summary section, changed to better describe affected airplanes.
4. In the Compliance paragraph in the Summary section, updated to direct to Paragraph 1.E..
5. Summary illustration updated to include new work.
6. In Paragraph 1.A., Effectivity, airplanes RT631, RT632, RT743, and RT876 have been removed from
the effectivity, and Group configurations added to the table.
7. In Paragraph 1.C., Reason, changed to include new work and added new paragraphs describing the
reason for revision.
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8. In Paragraph 1.D., Description, updated work summary, added reason for revision and maintenance
zone data.
9. In Paragraph 1.E., Compliance, added Airworthiness Directive statement and new compliance information
in tabular format.
10. In Paragraph 1.F., Approval, updated approval statement and added new Airworthiness Directive
statement.
11. In Paragraph 1.G., Manpower, added new manpower tables for repeat inspections.
12. In Paragraph 1.J., References, added new SRP and AD references.
13. In Paragraph 1.K., Publications Affected, a Damage Tolerance statement was added.
14. In Paragraph 2.B., Industry Support Information, revised the statement.
15. In Paragraph 3.B., Work Instructions, updated to include new general information and new inspections.
16. FIGURE 1 was deleted and Logic Diagram moved to Appendix A and Appendix B.
17. In FIGURE 2, added group information.
18. In FIGURE 3, added group information.
19. In FIGURE 4, added group information, changed sheet 2 and step table.
20. FIGURE 5 was added for HFEC Inspection.
21. APPENDIX A and APPENDIX B were added to include new Logic Diagrams.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity and format changes,
to show the location of all content changes.
Pages with no vertical lines have no changes.
REVISION HISTORY
September 18, 2003Original Issue:
January 09, 2015Revision 1:
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Commercial 
Airplanes
747
Service Bulletin
ALERT
SummaryNumber: 747-53A2494Original Issue: September 18, 2003
Revision 1: January 09, 2015
ATA System: 5312
SUBJECT: FUSELAGE - Section 46 - Body Station 2231 Frame Inner Chord Crack Inspection and
Repair
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
Accomplishment of this service bulletin will make sure that the body frame at station 2231 at stringer 26 does
not have any nicks, scratches, and / or gouges, and has no cracks. Cracks can initiate at nicks, scratches, and
/ or gouges. If not repaired, cracks could result in damage to the adjacent structure which could result in rapid
depressurization of the airplane.
The body frame at station 2231 is forward of the number 5 main entry door opening. The door 5 lower main sill
goes through a cutout in the station 2231 frame at stringer 26. Boeing investigation indicates that during production,
the door lower main sill chord can rub the station 2231 frame. If the sill rubs the frame, nicks, scratches, and /
or gouges in the frame inner chord can occur which can cause frame cracks. Cracks in the inner chords and
web at this location could extend with continued operation and fully cut the frame. If the frame becomes fully
cut, skin cracks could occur which could cause a rapid depressurization of the airplane.
One operator has reported cracked inner chords (forward and aft) and a cracked web at station 2231 and stringer
26L. Refer to Paragraph 1.C., Reason, for a detailed service history.
Airplane line numbers 1334 and on were delivered with additional checks to ensure no nicks, scratches, and/or
gouges were added during the production process.
Inspections accomplished in accordance with Service Bulletin 747-53A2450 R07 are an acceptable substitute
for the inspections specified in this service bulletin. Airplane line numbers 1-1419, except 747SP and 747-400
LCF, are affected by Service bulletin 747-53A2450 R07 .
This table is provided to operators for planning purposes only. Refer to the applicable sections for more
information.
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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
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
NoOperator Supplied Parts/Material
Paragraph 2.F., Special Tooling Necessary to
do this Service Bulletin
NoSpecial Tooling Required
Boeing Service Related Problems (SRP) 747-SRP-53-0202 and 747-SRP-53-0452 are related to this service
bulletin.
ACTION
Do a detailed inspection for nicks, scratches, and / or gouges of the station 2231 frame inner chords (forward
and aft), and web, at stringer 26 at the edge and side of the inner chords and do a surface High Frequency Eddy
Current (HFEC) inspection of the Station 2231 frame inner chords (forward and aft), for cracks. If any nicks,
scratches, and / or gouges are found, repair in accordance with the Structural Repair Manual (SRM) before next
flight. If cracks are found do a repair in accordance with the SRM, or contact Boeing for repair instructions,
before further flight. Repeat the HFEC inspection for cracks in accordance with Paragraph 1.E., Compliance.
EFFECTIVITY
747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F
and 747SR Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s).
COMPLIANCE
Refer to Paragraph 1.E., Compliance.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are available for airplanes in warranty as of November 22, 2002. Please refer to
Paragraph 2.B., Industry Support Information.
MANPOWER
Elapsed HoursTotal Task HoursAirplanes
34Groups 1 and 3
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Elapsed HoursTotal Task HoursAirplanes
34Groups 2 and 4 (with two MED #5)
1.52Groups 2 and 4 (with one MED #5)
MATERIAL INFORMATION
None.
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BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
STA
2231
SEE (
DOOR 5 LEFT
DOOR 5 RIGHT OPPOSITE  →FUD
DOOR 5 LEFT
MAIN DECK  S-25L
FLOOR
LOWER
MAIN
SILL
S-26L
UP
FWD
DO A DETAILED VISUAL INSPECTION FOR
NICKS, SCRATCHES, AND/OR GOUGES AND
UP  A SURFACE HFEC INSPECTION FOR CRACKS,  ON THE INNER CHORDS (FORWARD AND
AFT), INNER CHORD EDGES, AND WEB
INBD  EDGE, IN THE HEAVILY SHADED AREA AND
A-A  HEAVILY SHADED EDGE.
Original Issue: September 18, 2003
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Commercial 
Airplanes
747
Service Bulletin
ALERT
Number: 747-53A2494
Original Issue: September 18, 2003
Revision 1: January 09, 2015
ATA System: 5312
SUBJECT: FUSELAGE - Section 46 - Body Station 2231 Frame Inner Chord Crack Inspection and
Repair
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
This service bulletin is applicable to 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400,
-400D, -400F and 747SR Airplanes, line numbers 1-1333, except 747 Large Cargo Freighter (LCF)
airplanes, in four Groups. The Variable Numbers and Group Information for the applicable airplanes
is given below.
Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
DESCRIPTIONCONFIGURATIONGROUP
747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747-400,
747-400D and 747SR airplanes, line number 1 through 1304, except
Combi, Special Freighter, Boeing Converted Freighter (BCF) and
747 Large Cargo Freighter (LCF) airplanes.
-1
That have not completed the original issue of this service bulletin.1
That have completed the original issue of this service bulletin.2
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DESCRIPTIONCONFIGURATIONGROUP
747-200B, 747-200C, 747-200F, 747-300, 747-400 and 747-400F
Freighter, Convertible, Combi, Special Freighter, and BCF airplanes,
line number 1 through 1304.
-2
That have not completed the original issue of this service bulletin.1
That have completed the original issue of this service bulletin.2
747-400 Passenger airplanes, from line number 1305 through 1333.-3
That have not completed the original issue of this service bulletin.1
That have completed the original issue of this service bulletin2
747-400F airplanes, from line number 1305 through 1333.-4
That have not completed the original issue of this service bulletin.1
That have completed the original issue of this service bulletin2
Airplane Models:
747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400,
747-400D, 747-400F, 747SR
GroupVariable Number
1RA001 - RA034
1RA101 - RA115
1RA161 - RA164
1RA201 - RA203
1RA216 - RA217
1RA245 - RA246
1RA251 - RA266
1RA301 - RA318
1RA351 - RA360
1RA369 - RA373
1RA401 - RA418
1RA501 - RA502
1RA521 - RA528
1RA532 - RA548
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GroupVariable Number
1RA551 - RA552
1RA559 - RA561
1RA581 - RA582
1RA585
1RA601 - RA602
1RA631 - RA635
1RA651 - RA652
1RA671 - RA677
1RA701 - RA702
1RA721 - RA731
1RA741 - RA745
2RA749 - RA750
1RA761 - RA762
1RA781 - RA784
1RA901 - RA916
1RB001 - RB016
1RB041 - RB044
1RB071 - RB075
1RB101 - RB102
2RB411 - RB413
2RB421
1RB601 - RB607
1RB681 - RB697
1RB711
1RB721 - RB723
1RB741 - RB748
1RD001 - RD004
1RD021 - RD022
1RD041 - RD059
1RD071 - RD072
1RD081 - RD083
1RD091 - RD092
1RD101 - RD104
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GroupVariable Number
1RD121 - RD127
1RD131 - RD144
1RD166 - RD167
1RD171 - RD172
1RD181 - RD183
2RD201 - RD204
1RD221 - RD227
1RD231 - RD235
1RD241 - RD243
1RD251 - RD262
1RD271 - RD272
1RD291 - RD292
1RD301 - RD302
1RD311
1RD351 - RD358
1RD361 - RD366
1RD381 - RD383
1RD411 - RD414
1RD421 - RD426
1RD431 - RD435
1RD441 - RD442
1RD451 - RD456
1RD461
1RD471 - RD475
1RD513 - RD519
2RD531 - RD533
2RD551
2RD561
2RD571
2RD581 - RD583
2RD591 - RD593
2RD601 - RD607
2RD621 - RD623
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GroupVariable Number
2RD641 - RD649
2RD651 - RD659
2RD661
2RD671
2RD681 - RD682
2RD691 - RD692
2RD701 - RD702
2RD721 - RD722
2RD741 - RD742
2RD751 - RD755
2RD761
2RD771 - RD775
2RD781 - RD783
2RD791 - RD792
1RE001
3RF001 - RF006
2RJ131 - RJ133
2RJ151 - RJ152
2RJ301 - RJ303
2RJ321 - RJ322
2RJ331 - RJ333
2RL401 - RL402
4RL403
2RL411 - RL419
4RL420 - RL421
4RL431 - RL432
2RL651 - RL654
4RL655
4RL671 - RL673
4RL681 - RL682
4RL751 - RL752
1RM001 - RM007
1RM010 - RM013
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GroupVariable Number
1RM021 - RM024
1RM026 - RM029
1RM036 - RM045
1RM051 - RM052
1RM071
1RM081 - RM084
1RM091
1RM096 - RM097
1RM116 - RM117
1RM126 - RM132
1RM136 - RM147
1RM156 - RM158
1RM166 - RM177
1RM191 - RM192
1RM231 - RM233
1RM241 - RM246
1RM261 - RM264
1RM316 - RM318
1RM331 - RM333
1RM341
1RM351 - RM355
1RM366 - RM367
3RM401 - RM402
3RM426
2RM801 - RM803
2RM811 - RM813
2RM851 - RM858
2RM861
4RM862
2RM871 - RM876
4RM877 - RM879
2RM881 - RM886
4RM887
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GroupVariable Number
2RM891 - RM899
2RM901 - RM904
4RM905 - RM906
2RM911
2RR001 - RR005
2RR021 - RR025
2RR031
2RR201 - RR206
2RR221 - RR226
2RR261 - RR267
2RR301 - RR310
2RR331 - RR332
2RR336
2RR341 - RR345
2RR361 - RR362
2RR421 - RR422
2RR431 - RR432
2RR441 - RR442
2RR451
2RR501 - RR504
2RR521 - RR522
2RR526
2RR531
2RR551 - RR556
2RR561
2RR566
2RR701
2RR721 - RR724
2RR746 - RR748
2RR851 - RR856
2RR861 - RR862
2RR951 - RR952
1RS001 - RS002
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GroupVariable Number
1RS201
1RS211 - RS212
1RS221 - RS222
1RS231 - RS241
1RS251 - RS259
1RS263
1RS265 - RS268
1RS271 - RS276
1RS291 - RS292
1RS301 - RS306
1RS311 - RS320
1RS331 - RS333
1RS341 - RS342
1RS699
2RS701 - RS703
2RS711 - RS713
2RS721 - RS722
2RS731 - RS732
2RS741 - RS743
2RS751 - RS752
2RS761 - RS762
2RS771
2RS781 - RS782
2RS786
2RT001 - RT014
2RT021 - RT022
2RT031 - RT035
2RT041 - RT047
2RT061
2RT071 - RT075
2RT101 - RT103
2RT121
2RT131 - RT137
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GroupVariable Number
2RT151 - RT152
2RT161 - RT168
1RT401 - RT412
1RT431 - RT447
1RT451 - RT469
1RT471 - RT499
1RT501 - RT535
1RT551 - RT568
1RT571 - RT591
1RT601 - RT630
1RT633 - RT657
1RT671 - RT673
1RT681 - RT682
1RT691 - RT699
1RT701 - RT704
1RT711 - RT717
1RT741 - RT742
1RT744 - RT757
1RT776 - RT777
1RT781 - RT784
1RT801 - RT803
1RT811 - RT814
1RT831 - RT837
1RT861 - RT864
1RT877 - RT880
1RT931 - RT932
1RT945 - RT949
1RT951 - RT955
1RT966 - RT967
1RU001 - RU006
1RU016 - RU017
1RU031 - RU032
1RU051 - RU052
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GroupVariable Number
1RU059 - RU062
1RU081 - RU083
1RU101 - RU102
1RU121 - RU132
1RU801 - RU809
1RU831 - RU841
2. Spares Affected
None.
B. Concurrent Requirements
None.
C. Reason
Accomplishment of this service bulletin will make sure that the body frame at station 2231 at stringer
26 does not have any nicks, scratches, and / or gouges, and has no cracks. Cracks can initiate at nicks,
scratches, and / or gouges. If not repaired, cracks could result in damage to the adjacent structure
which could result in rapid depressurization of the airplane.
The body frame at station 2231 is forward of the number 5 main entry door opening. The door 5 lower
main sill goes through a cutout in the station 2231 frame at stringer 26. Boeing investigation indicates
that during production, the door lower main sill chord can rub the station 2231 frame. If the sill rubs the
frame, nicks, scratches, and / or gouges in the frame inner chord can occur which can cause frame
cracks. Cracks in the inner chords and web at this location could extend with continued operation and
fully cut the frame. If the frame becomes fully cut, skin cracks could occur which could cause a rapid
depressurization of the airplane.
One operator has reported cracked inner chords (forward and aft) and a cracked web at station 2231
and stringer 26L. The following table provides service history details.
Service History
ReportCycles / Hours
Both chords and web severed on BS 2231 Frame at
Stringer 26L
14,687 / 87,877
Between the release of the original issue and Revision 1 of this service bulletin, there have been further
reports of cracking in the inner chords at station 2231 and stringer 26 (left and right). The crack at this
location is also inspected in accordance with 747-53A2450 R07, which must begin before 16,000 flight
cycles. The following table provides the service history details of one of the reports provided between
the original issue and Revision 1.
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Service History
ReportCycles / Hours
0.25" crack on BS 2231 Frame inner chord at Stringer
26R
11,023 / 91,788
Airplane line numbers 1334 and on were delivered with additional checks to ensure no nicks, scratches,
and/or gouges were added during the production process.
Inspections accomplished in accordance with Service Bulletin 747-53A2450 Revision 7 are similar to
the inspections specified in this service bulletin. Airplane line numbers 1-1419, except 747SP and
747-400LCF, are affected by Service bulletin 747-53A2450 R07.
Revision 1 is sent to add a repeat surface High Frequency Eddy Current (HFEC) inspection of the
Station 2231 frame inner chord.
Boeing Service Related Problems (SRP) 747-SRP-53-0202 and 747-SRP-53-0452 are related to this
service bulletin.
D. Description
Do a detailed inspection for nicks, scratches, and / or gouges of the station 2231 frame inner chords
(forward and aft) at stringer 26 at the edge and side of the inner chords and do a surface High Frequency
Eddy Current (HFEC) inspection of the frame inner chords (forward and aft) for cracks. If any nicks,
scratches, and / or gouges are found, repair in accordance with the Structural Repair Manual (SRM)
before next flight. If cracks are found do a repair in accordance with the SRM, or contact Boeing for
repair instructions, before further flight. Repeat the HFEC inspection for cracks in accordance with
Paragraph 1.E., Compliance.
The airplane effectivity is divided into four groups because of access requirements.
Revision 1 - More work is necessary on airplanes changed or inspected in accordance with the original
issue of this service bulletin. Do HFEC initial inspection and repeat inspections in accordance with this
revision.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1:
Affected Maintenance Zones
ZoneModel
271, 272747-100, 747-100B, 747-100B
SUD, 747-200B, 747-300, 747-
400, 747-400D, 747SR
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Group 2:
Affected Maintenance Zones
ZoneModel
271, 272747-200B, 747-200C, 747-200F,
747-300, 747-400, 747-400F
Group 3:
Affected Maintenance Zones
ZoneModel
271, 272747-400
Group 4:
Affected Maintenance Zones
ZoneModel
271, 272747-400F
E. Compliance
Federal Aviation Administration (FAA) Airworthiness Directive 2005-01-09 is related to this service
bulletin. The effective date of AD 2005-01-09 is February 11, 2005.
Group 1-4, Configuration 1:
Table 1: Station 2231 Frame Inner Chord - Detailed and HFEC Inspections
Repeat Interval
(Not to Exceed)
Compliance Time
(Whichever Occurs Later)
ActionCondition
-Within 1,500
flight cycles
after the ef-
fective date
of AD 2005-
01-09.
Before
10,000 total
flight cycles
Do a detailed inspec-
tion for nicks, scratch-
es, or gouges of the
frame inner chords and
web in accordance with
Paragraph 3.B., Work
Instructions, Step 3 (a)
All airplanes.
AND
-Within 1,500
flight cycles
after the re-
lease of Revi-
sion 1 of this
service bul-
letin.
Before
10,000 total
flight cycles.
Do a surface HFEC in-
spection of the frame
inner chords for cracks
in accordance with
Paragraph 3.B., Work
Instructions, Step 4. (a)
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Group 1-4, Configuration 1:
Table 1: Station 2231 Frame Inner Chord - Detailed and HFEC Inspections
Repeat Interval
(Not to Exceed)
Compliance Time
(Whichever Occurs Later)
ActionCondition
--Before fur-
ther flight.
Repair in accordance
with Paragraph 3.B.,
Work Instructions, Step
5
Nicks, scratches or
gouges found and no
cracks found.
AND
3,000 flight cy-
cles.
--Repeat the surface
HFEC inspection of the
frame inner chords for
cracks in accordance
with Paragraph 3.B.,
Work Instructions, Step
11. (a)
--Before fur-
ther flight.
Repair in accordance
with Paragraph 3.B.,
Work Instructions, Step
7
Any crack found.
AND
3,000 flight cy-
cles.
--Repeat the surface
HFEC inspection of the
frame inner chords for
cracks in accordance
with Paragraph 3.B.,
Work Instructions, Step
11. (b)
3,000 flight cy-
cles.
--Repeat the surface
HFEC inspection of the
frame inner chords for
cracks in accordance
with Paragraph 3.B.,
Work Instructions, Step
11. (a)
No nicks, scratches or
gouges found and no
cracks found.
(a) Inspections accomplished in accordance with Service Bulletin 747-53A2450 Revision 7
are similar to the inspections specified in this service bulletin.
(b) For airplanes with inner chords repaired in accordance with Paragraph 3.B., Work Instruc-
tions Step 7, do the inspections in accordance with Paragraph 3.B., Work Instructions Step
11 for the chords that were not repaired.
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Group 1-4, Configuration 2:
Table 2: Station 2231 Frame Inner Chord - HFEC Inspections
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 1,500
flight cycles af-
ter the release
of Revision 1 of
this service bul-
letin.
Before 10,000
total flight cy-
cles.
Do the surface HFEC in-
spection of the frame in-
ner chords for cracks in
accordance with Para-
graph 3.B., Work Instruc-
tions, Step 6. (a)
All airplanes.
-Before further flight.Repair in accordance with
Paragraph 3.B., Work In-
structions, Step 7.
Any crack found.
AND
3,000 flight cycles.--Repeat the surface HFEC
inspection of the frame
inner chords for cracks in
accordance with Para-
graph 3.B., Work Instruc-
tions, Step 11. (b)
3,000 flight cycles.--Repeat the surface HFEC
inspection of the frame
inner chords for cracks in
accordance with Para-
graph 3.B., Work Instruc-
tions, Step 11. (a)
No crack found.
(a) Inspections accomplished in accordance with Service Bulletin 747-53A2450 Revision 7 are similar to the
inspections specified in this service bulletin.
(b) For airplanes with inner chords repaired in accordance with Paragraph 3.B., Work Instructions Step 7,
do the inspections in accordance with Paragraph 3.B., Work Instructions Step 11 for the chords that were
not repaired.
Logic diagrams showing compliance tasks and compliance times are included as an aid in Appendix
A and B.
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.
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The Manager of the FAA Seattle ACO approves the accomplishment of the inspection as defined by
Boeing SB 747-53A2494 Revision 1 as an AMOC to the accomplishment of the inspection as defined
by Boeing SB 747-53A2494 Original Issue required by paragraph (f) and (h) of AD 2005-01-09. All
provisions of AD 2005-01-09 that are not specifically referenced in the above statement remain fully
applicable and must be complied with accordingly.
G. Manpower
The tables below show estimates 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 examine the work
— Time to cure the materials
— Time to make the parts
— Time to find the tools.
GROUP 1 AND GROUP 3 AIRPLANES:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
111Open Access
122Inspection
111Close Access
34TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
GROUP 2 AND GROUP 4 AIRPLANES WITH ACTIVE OR INACTIVE MAIN
ENTRY DOOR 5 ON BOTH SIDES OF THE AIRPLANE:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
111Open Access
122Inspection
111Close Access
34TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
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GROUP 2 AND GROUP 4 AIRPLANES WITH ACTIVE OR INACTIVE MAIN
ENTRY DOOR 5 ON ONE SIDE OF THE AIRPLANE:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
.5.51Open Access
.512Inspection
.5.51Close Access
1.52TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
GROUP 1 AND GROUP 3 AIRPLANES:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
111Open Access
122Repeat Inspection
111Close Access
34TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
GROUP 2 AND GROUP 4 AIRPLANES WITH ACTIVE OR INACTIVE MAIN
ENTRY DOOR 5 ON BOTH SIDES OF THE AIRPLANE:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
111Open Access
122Repeat Inspection
111Close Access
34TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
GROUP 2 AND GROUP 4 AIRPLANES WITH ACTIVE OR INACTIVE MAIN
ENTRY DOOR 5 ON ONE SIDE OF THE AIRPLANE:
Elapsed HoursTask-HoursNumber of Per-
sons
Task
.5.51Open Access
.512Repeat Inspection
.5.51Close Access
1.52TOTAL FOR EACH AIRPLANE (a)
(a) Additional time may be required if repairs are accomplished.
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H. Weight and Balance Changes
None.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data:
a. Service Related Problem (SRP) 747-SRP-53-0202
b. Service Related Problem (SRP) 747-SRP-53-0452
c. 747-100/-200/-300 Maintenance Manual (AMM) Subjects 25-21-03, 25-21-04, 25-59-05
d. 747-400 Maintenance Manual (AMM) Subjects 25-21-03, 25-21-04
e. 747-100/-200/-300 Structural Repair Manual (SRM) Subjects 51-10-01, 53-10-04 Figure 147
f. 747-400 Structural Repair Manual (SRM) Subjects 51-10-00, 53-60-07 Repair 7
g. 747-400F Structural Repair Manual (SRM) Subject 53-60-07 Repair 7
h. 747-400SF Structural Repair Manual (SRM) Subject 53-60-07 Repair 7
i. 747 Nondestructive Test (NDT) Manual D6-7170, Part 6, Subject 51-00-00
j. Boeing Service Bulletin 747-53-2450
k. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2005-01-09, 2013-17-08
2. Data Supplied with this Service Bulletin:
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin:
None.
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.
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L. Interchangeability and Intermixability of Parts
Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.
M. Software Accomplishment Summary
Not affected.
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2.    MATERIAL INFORMATION
A. Material - Price and Availability
None.
B. Industry Support Information
Boeing warranty remedies are available for the original issue Service Bulletin work statement for 747
airplanes in warranty as of November 22, 2002. For inspection man-hour reimbursement for airplanes
in warranty as of that date, send a warranty claim to BCA Fleet Support Contracts - Warranty. If the
condition described in this service bulletin is found during inspection for airplanes in warranty as of that
date and additional man hours are required, send a warranty claim to BCA Fleet Support Contracts -
Warranty. Please refer to this service bulletin number and reference the airplane variable numbers in
your purchase order.
Boeing warranty remedies are not available for the additional work statement described in Revision 1
of this Service Bulletin.
C. Parts Necessary for Each Airplane
1. Kits/Parts:
None.
2. Parts and Materials Supplied by the Operator:
None.
3. Parts Modified and Reidentified:
None.
4. Parts Removed and Not Replaced:
None.
D. Parts Necessary to Change Spares
None.
E. Special Tooling - Price and Availability
None.
F. Special Tooling Necessary to do this Service Bulletin
No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance
and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine
operator tool supply to make sure all necessary tools are available.
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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 747 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 747
Airplane Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 747
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. 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.
6. 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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7. Boeing Service Letter 747-SL-51-048, Damage Reporting and Repair Plan/Design
Guidelines, is an acceptable procedure to request information from Boeing for
additional structural repair instructions. The Service Letter describes what information
must be provided to Boeing before a structural repair can be provided.
8. Refer to Appendix A and B for logic diagrams. Logic diagrams are provided as an
aid only. Information contained in Paragraph 1.E., Compliance is the primary source
for compliance times. Information in Paragraph 3.B., Work Instructions is the primary
source for tasks required for compliance.
9. 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.
10. 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.
11. 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.
12. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS
are in Paragraph 1.E., Compliance.
13. Refinish bare metal areas to match surrounding area.
B. WORK INSTRUCTIONS
1. Airplanes configured to carry passengers in the aft body should use FIGURE 2 for access.
2. Airplanes configured to carry cargo in the aft body should use FIGURE 3 for access.
3. Group 1-4, Configuration 1:
Do a detailed inspection of the Station 2231 Frame Inner Chord (forward and aft) surfaces and
edge and web edge for nicks, scratches, or gouges in accordance with FIGURE 4.
4. Group 1-4, Configuration 1:
Do a surface High Frequency Eddy Current (HFEC) inspection on the Station 2231 Frame Inner
Chord (forward and aft) surfaces for cracks in accordance with Figure 4.
5. Group 1-4, Configuration 1:
If any nicks, scratches, or gouges are found and no cracks were found in accordance with Step
4, repair as follows:
a. Rework in accordance with 747-100/-200/-300 SRM Section 51-10-01 (747-400 SRM 51-10-02,
747-400F SRM 51-10-02, 747-400SF SRM 51-10-02).
b. Get a surface finish of 63 micro-inches or better. Break sharp edges.
c. Maintain a minimum 2D edge margin to adjacent fastener locations.
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d. Maintain a minimum rework radius of 0.30 inch.
e. Group 1-2, Configuration 1:
Measure minimum distance "A" from the outboard edge of the chord flange to the rework
radius as shown in FIGURE 4. Minimum acceptable dimension is:
0.625 inch
If rework results in less than this dimension, contact Boeing for repair instructions and do the
repair.
f. Group 3-4, Configuration 1:
Measure minimum distance "A" from the outboard edge of the chord flange to the rework
radius as shown in FIGURE 4. Minimum acceptable dimension is:
0.510 inch
If rework results in less than this dimension, contact Boeing for repair instructions and do the
repair.
g. Accomplish a surface High Frequency Eddy Current (HFEC) inspection of the reworked edge
to ensure a crack free condition. Inspect in accordance with Nondestructive Test (NDT) Manual
D6-7170, Part 6, Subject 51-00-00, Procedure 4 or 23.
6. Group 1-4, Configuration 2:
Do a surface HFEC inspection on the Station 2231 Frame Inner Chord (forward and aft) surfaces
for cracks in accordance with FIGURE 5.
7. If any crack is found, repair in accordance with 747-100/200/300 SRM 53-10-04 (Figure 147),
747-400 SRM 53-60-07 (Repair 7), 747-400F SRM 53-60-07 (Repair 7), 747-400SF SRM 53-60-07
(Repair 7), or contact Boeing for repair instructions and do the repair.
NOTE: After the repair, it will be necessary to do inspections of the repaired area of the frame
in accordance with 747-100/200/300 SRM 53-10-04 (Figure 147), 747-400 SRM 53-60-07
(Repair 7), 747-400F SRM 53-60-07 (Repair 7), 747-400SF SRM 53-60-07 (Repair 7),
as applicable. If only one of the aft or forward inner chords is repaired, repeat the
inspections in accordance with Step 11 for the chords that are not repaired.
8. Airplanes configured to carry passengers in the aft body should use FIGURE 2 for restoration.
9. Airplanes configured to carry cargo in the aft body should use FIGURE 3 for restoration.
10. Put the airplane back to a serviceable condition.
11. Do a repeat surface High Frequency Eddy Current (HFEC) inspection on the Station 2231 Frame
Inner Chord (forward and aft) surfaces for cracks in accordance with FIGURE 5. If any crack is
found, repair in accordance with 747-100/200/300 SRM 53-10-04 (Figure 147), 747-400 SRM
53-60-07 (Repair 7), 747-400F SRM 53-60-07 (Repair 7), 747-400SF SRM 53-60-07 (Repair 7),
or contact Boeing for repair instructions and do the repair.
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NOTE: After the repair, it will be necessary to do inspections of the repaired area of the frame
in accordance with 747-100/200/300 SRM 53-10-04 (Figure 147), 747-400 SRM 53-60-07
(Repair 7), 747-400F SRM 53-60-07 (Repair 7), 747-400SF SRM 53-60-07 (Repair 7),
as applicable. If only one of the aft or forward inner chords is repaired, repeat the
inspections in accordance with Step 11 for the chords that are not repaired.
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FIGURE 1: THIS FIGURE IS DELETED
(SHEET 1 OF 1)
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BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
This Figure applies only to: Group 1, 3.
MAIN DECK FLOOR
LEFT SIDE SHOWN,
RIGHT SIDE OPPOSITE
W31307
FIGURE 2: ACCESS / RESTORATION FOR CONFIGURATION WITH PASSENGERS IN THE AFT BODY
(SHEET 1 OF 2)
Original Issue: September 18, 2003
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Work - See page 1 for details.  36 of 48

### Page 37

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for one side of the airplane.
NOTESQTYREFERENCESNAMETASKSTEP
-1747 AMM 25-21-03, 747-
400 AMM 25-21-03
Lower transition
Panel
Remove1
(a)-747 AMM 25-59-05, 747
AMM 25-21-04,  747-400
AMM 25-21-04
Insulation BlanketsPull Back2
(a) Pull back insulation blankets in area of inspection. Insulation blankets not shown in figure.
NOTESQTYREFERENCESNAMETASKSTEP
--747 AMM 25-59-05, 747
AMM 25-21-04, 747-400
AMM 25-21-04
Insulation BlanketsInstall3
-1747 AMM 25-21-03, 747-
400 AMM 25-21-03
Lower transition
Panel
Install4
FIGURE 2: ACCESS / RESTORATION FOR CONFIGURATION WITH PASSENGERS IN THE AFT BODY
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: September 18, 2003
747-53A2494Revision 1 January 09, 2015
37 of 48
BOEING SERVICE BULLETIN 747-53A2494
ALERTALERT

### Page 38 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
This Figure applies only to: Group 2, 4.
2)3
MAIN DECK FLOOR
LEFT SIDE SHOWN, RIGHT SIDE
OPPOSITE ON COMBI, CONVERTIBLE AND
AND SPECIAL FREIGHTER AIRPLANES  W31359
FIGURE 3: ACCESS / RESTORATION FOR CONFIGURATION WITH CARGO IN THE AFT BODY
(SHEET 1 OF 2)
Original Issue: September 18, 2003
Revision 1 January 09, 2015  Export Controlled ECCN: 9E991 - BOEING  PROPRIETARY - Copyright © Unpublished  747-53A2494
Work - See page 1 for details.  38 of 48

### Page 39

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for one side of the airplane.
NOTESQTYREFERENCESNAMETASKSTEP
-1747 AMM 25-59-01, 747-
400 AMM 25-59-01
Lower transition
Panel
Remove1
(a)-747 AMM 25-59-05, 747-
400 AMM 25-59-05
Insulation BlanketsPull Back2
(a) Pull back insulation blankets in area of inspection. Insulation blankets not shown in figure.
NOTESQTYREFERENCESNAMETASKSTEP
--747 AMM 25-59-05, 747-
400 AMM 25-59-05
Insulation BlanketsInstall3
-1747 AMM 25-59-01, 747-
400 AMM 25-59-01
Lower transition
Panel
Install4
FIGURE 3: ACCESS / RESTORATION FOR CONFIGURATION WITH CARGO IN THE AFT BODY
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: September 18, 2003
747-53A2494Revision 1 January 09, 2015
39 of 48
BOEING SERVICE BULLETIN 747-53A2494
ALERTALERT

### Page 40 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
This Figure applies only to: Group 1-4, Configuration 1.
SEE A
STA
2231
DOOR 5 LEFT
DOOR 5 RIGHT OPPOSITE  →FWD
DOOR 5 LEFT
MAIN DECK  S-25L
FLOOR
LOWER
MAIN
SILL
UP  S-26L
• FWD
LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE
ON PASSENGER, COMBI, CONVERTIBLE  W32516
AND SPECIAL FREIGHTER AIRPLANES
FIGURE 4: INSPECTION
(SHEET 1 OF 3)
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Work - See page 1 for details.  40 of 48

### Page 41 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
POTENTIAL CRACK
LOCATION
S-26L
SUP
INBD
S-29L
DIMENSION A
A-A
INNER CHORD (FWD)
WEB
OUTBOARD
EDGE OF
CHORD FLANGE
FWDS
INSPECTION  INNER CHORD (AFT)
AREA  B-B
FIGURE 4: INSPECTION
(SHEET 2 OF 3)
Original Issue: September 18, 2003
Revision 1 January 09, 2015  Export Controlled ECCN: 9E991 - BOEING  747-53A2494
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.  41 of 48

### Page 42

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
NOTESREFERENCESPROCEDURENAMETASKSTEP
(a)-Detailed InspectionStation 2231
Frame Inner
Chords (surfaces
and edge) and
Web Edge
Inspect1
(b)747 Nondestructive
Test (NDT) Manual
D6-7170, Part 6,
Subject 51-00-00,
Procedure 4 or 23
Surface High Fre-
quency Eddy Cur-
rent (HFEC) Inspec-
tion
Station 2231
Frame Inner
Chords (surfaces)
Inspect2
(a) Do a detailed inspection of the Station 2231 Frame Inner Chords (forward and aft surfaces
and edge) and Web edge for nicks, scratches, and / or gouges.
(b) Do a surface HFEC inspection on the Station 2231 Frame Inner Chords (forward and aft sur-
faces) for cracks.
FIGURE 4: INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
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BOEING SERVICE BULLETIN 747-53A2494
ALERTALERT

### Page 43 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
SEE A
STA
2231
DOOR 5 LEFT
DOOR 5 RIGHT OPPOSITE  →FWD
DOOR 5 LEFT
MAIN DECK  S-25L
FLOOR
LOWER
MAIN
SILL
S-26L
FWD
LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE
ON PASSENGER, COMBI, CONVERTIBLE  2340369
AND SPECIAL FREIGHTER AIRPLANES
FIGURE 5: HFEC INSPECTION
(SHEET 1 OF 3)
Original Issue: September 18, 2003
Revision 1 January 09, 2015  PROPRIETARY - Copyright © Unpublished  Export Controlled ECCN: 9E991 - BOEING  Work - See page 1 for details.  747-53A2494  43 of 48

### Page 44 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
POTENTIAL CRACK
LOCATION
• S-26L
SUP
INBD
S-29L
DIMENSION 'A
A-A
INNER CHORD (FWD)
. WEB
OUTBOARD
EDGE OF
CHORD FLANGE
FWDS
INSPECTION  INNER CHORD (AFT)  2340370
AREA  B-B
FIGURE 5: HFEC INSPECTION
(SHEET 2 OF 3)
Original Issue: September 18, 2003
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Work - See page 1 for details.  44 of 48

### Page 45

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
NOTESREFERENCESPROCEDURENAMETASKSTEP
(a)747 Nondestructive
Test (NDT) Manual
D6-7170, Part 6,
Subject 51-00-00,
Procedure 4 or 23
Surface High Fre-
quency Eddy Cur-
rent (HFEC) Inspec-
tion
Station 2231
Frame Inner
Chords (surfaces)
Inspect1
(a) Do a surface HFEC inspection on the Station 2231 Frame Inner Chords (forward and aft sur-
faces) for cracks.
FIGURE 5: HFEC INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991 - BOEING
PROPRIETARY - Copyright © Unpublished
Work - See page 1 for details.
Original Issue: September 18, 2003
747-53A2494Revision 1 January 09, 2015
45 of 48
BOEING SERVICE BULLETIN 747-53A2494
ALERTALERT

### Page 46 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
This Appendix applies only to: Group 1-4, Configuration 1.
ALL AIRPLANES
BEFORE 10,000 TOTAL FLIGHT
CYCLES OR WITHIN 1,500 FLIGHT
CYCLES AFTER THE EFFECTIVE
DATE OF AD 2005-01-09,
WHICHEVER COMES LATER, DO
A DET AND HFEC INSPECTION  >
NO  YES
ANY CRACK
FOUND.
NO  SCRATCH AND /  ANY NICK,  YES  FURTHER FLIGHT  REPAIR BEFORE
OR GOUGE  (SRM REPAIR)
FOUND.
REPAIR BEFORE  PERFORM
FURTHER FLIGHT  POST-REPAIR
(RADIUS REWORK  INSPECTION OF
REPAIR).  THE REPAIRED
CHORD PER SRM.
INSPECTIONS ACCOMPLISHED IN ACCORDANCE WITH 747-53A2450 REVISION 7 ARE SIMILAR
TO THE INSPECTIONS SPECIFIED IN THIS SERVICE BULLETIN.
CHORD IS REPAIRED, CONTINUE INSPECTION OF THE OTHER CHORDS PER THIS  THE FORWARD AND AFT CHORDS CAN BE REPAIRED INDEPENDENTLY. IF ONLY ONE  2340371
SERVICE BULLETIN.
APPENDIX A: LOGIC DIAGRAM
(SHEET 1 OF 2)
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### Page 47 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
DO REPEAT HFEC
SURFACE INSPECTION
AT INTERVALS NOT TO
EXCEED 3000 FLIGHT
CYCLES.
YES
ANY CRACK
FOUND.
REPAIR BEFORE
FURTHER FLIGHT
(SRM REPAIR)  NO
PERFORM
POST-REPAIR
INSPECTION OF
THE REPAIRED
CHORD PER SRM.
INSPECTIONS ACCOMPLISHED IN ACCORDANCE WITH 747-53A2450 REVISION 7 ARE SIMILAR
TO THE INSPECTIONS SPECIFIED IN THIS SERVICE BULLETIN.
THE FORWARD AND AFT CHORDS CAN BE REPAIRED INDEPENDENTLY. IF ONLY ONE
CHORD IS REPAIRED, CONTINUE INSPECTION OF THE OTHER CHORDS PER THIS
SERVICE BULLETIN.
2372764
APPENDIX A: LOGIC DIAGRAM
(SHEET 2 OF 2)
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### Page 48 (OCR)

BOEING SERVICE BULLETIN 747-53A2494
ALERT  ALERT
This Appendix applies only to: Group 1-4, Configuration 2.
ALL AIRPLANES
BEFORE 10,000 TOTAL FLIGHT
CYCLES OR WITHIN 1,500 FLIGHT
CYCLES AFTER THE EFFECTIVE
DATE REVISION 1 OF THIS
SERVICE BULLETIN, WHICHEVER
COMES LATER, DO A SURFACE
HFEC INSPECTION
YES
ANY CRACK
FOUND.
REPAIR BEFORE
FURTHER FLIGHT
(SRM REPAIR).
PERFORM
POST-REPAIR
INSPECTION OF
THE REPAIRED
CHORD PER SRM.
DO REPEAT HFEC SURFACE
INSPECTION AT INTERVALS NOT
TO EXCEED 3000 FLIGHT CYCLES.
INSPECTIONS ACCOMPLISHED IN ACCORDANCE WITH 747-53A2450 REVISION 7 ARE SIMILAR
TO THE INSPECTIONS SPECIFIED IN THIS SERVICE BULLETIN.
THE FORWARD AND AFT CHORDS CAN BE REPAIRED INDEPENDENTLY.IF ONLY ONE
CHORD IS REPAIRED, CONTINUE INSPECTIONOF THE OTHER CHORD PER THIS  SERVICE BULLETIN.  2348798
APPENDIX B: LOGIC DIAGRAM
(SHEET 1 OF 1)
Original Issue: September 18, 2003
Revision 1 January 09, 2015  PROPRIETARY - Copyright © Unpublished  Export Controlled ECCN: 9E991 - BOEING  747-53A2494
Work - See page 1 for details.  48 of 48

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