# Boeing Alert Service Bulletin 747-53A2747: Revision 2

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- Document: [Boeing Alert Service Bulletin 747-53A2747](https://openairdocs.org/service-documents/boeing/747-53a2747.md)
- Title as filed: Boeing - Service Bulletin - SB-747-53A2747-02
- Pages: 284
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## Text

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Commercial 
Airplanes
747
Service Bulletin
Number: 747-53A2747
Original Issue: July 08, 2010
Revision 2: February 22, 2012
ATA System: 5331
SUBJECT: FUSELAGE - Skin - Inspection, Repair and Modification of Section 41 Skin Panels
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 730-774). 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 © 2010 The Boeing Company
Unpublished Work - All Rights Reserved
Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable
subject matter. Boeing also claims copyright in this document as a compilation and/or collective work.
This document includes proprietary information owned by The Boeing Company and/or one or more third parties.
Treatment of the document and the information it contains is governed by contract with Boeing. For more
information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.
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, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the
Boeing livery 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.
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3.0

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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 1
C. Reason ................................................ 2 1
D. Description .............................................. 2 2
E. Compliance .............................................. 2 4
F. Approval ............................................... 5 3
G. Manpower .............................................. 5 4
H. Weight and Balance Changes .................................... 5 5
I. Electrical Load Data ......................................... 5 5
J. References .............................................. 5 5
1. Existing Data .......................................... 5 5
2. Data supplied with this Service Bulletin ............................ 5 6
3. Installation Drawings Used in the Preparation of this Service Bulletin ............ 5 6
K. Publications Affected ........................................ 5 6
L. Interchangeability and Intermixability of Parts ........................... 5 6
2. MATERIAL INFORMATION ........................................ 5 7
A. Material - Price and Availability ................................... 5 7
B. Industry Support Information .................................... 5 7
C. Parts Necessary For Each Airplane ................................. 5 7
1. Kits/Parts ............................................ 5 7
2. Parts and Materials Supplied by the Operator ........................ 5 7
3. Parts Modified and Reidentified ................................ 5 7
4. Parts Removed and Not Replaced .............................. 5 7
D. Parts Necessary to Change Spares ................................. 5 7
E. Special Tooling - Price and Availability ............................... 5 7
F. Special Tooling Necessary to do this Service Bulletin ....................... 5 7
3. ACCOMPLISHMENT INSTRUCTIONS .................................. 5 9
A. GENERAL INFORMATION ..................................... 5 9
B. WORK INSTRUCTIONS ....................................... 6 0
FIGURE 1: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - LEFT SIDE PLUS
CENTER LOWER LOBE [Group 1-4, 12] ........................... 6 6
FIGURE 2: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - RIGHT SIDE [Group
1-4, 12] ............................................. 7 4
FIGURE 3: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - LEFT SIDE PLUS
CENTER LOWER LOBE [Group 5-7, 13] ........................... 8 0
FIGURE 4: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - RIGHT SIDE [Group
5-7, 13] ............................................. 8 8
FIGURE 5: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - LEFT SIDE PLUS
CENTER LOWER LOBE [Group 8-11, 14] .......................... 9 4
FIGURE 6: INSPECTION FOR SKIN CRACKS AND DISCREPANT FASTENERS - RIGHT SIDE [Group
8-11, 14] ............................................ 1 0 2
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FIGURE 7: INSPECTION FOR DOUBLER DISBOND - LEFT SIDE PLUS CENTER LOWER LOBE [Group
1-4, 12] ............................................ 1 0 8
FIGURE 8: INSPECTION FOR DOUBLER DISBOND - RIGHT SIDE [Group 1-4, 12] ......... 1 4 0
FIGURE 9: INSPECTION FOR DOUBLER DISBOND - LEFT SIDE PLUS CENTER LOWER LOBE [Group
5-7, 13] ............................................ 1 6 4
FIGURE 10: INSPECTION FOR DOUBLER DISBOND - RIGHT SIDE [Group 5-7, 13] ......... 1 9 0
FIGURE 11: INSPECTION FOR DOUBLER DISBOND - LEFT SIDE PLUS CENTER LOWER LOBE [Group
8-11, 14] ............................................ 2 1 3
FIGURE 12: INSPECTION FOR DOUBLER DISBOND - RIGHT SIDE [Group 8-11, 14] ........ 2 4 5
FIGURE 13: TERMINATING MODIFICATION FOR EXISTING REPAIR DOUBLERS ......... 2 7 5
FIGURE 14: LOCATION OF INSPECTION ZONES ............................ 2 7 6
FIGURE 15: SUPPLEMENTAL INSPECTION FOR DISBONDED DOUBLER [Group 1-7, 12-13] . . . 278
FIGURE 16: SUPPLEMENTAL INSPECTION FOR DISBONDED DOUBLERS [Group 8-11, 14] . . . 282
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Commercial 
Airplanes
747
Service Bulletin
Revision Transmittal SheetNumber: 747-53A2747Original Issue: July 08, 2010
Revision 2: February 22, 2012
ATA System: 5331
SUBJECT: FUSELAGE - Skin - Inspection, Repair and Modification of Section 41 Skin Panels
This revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
No more work is necessary on the airplanes changed in accordance with Revision 1 of this service bulletin.
NOTE: With Revision 1 to this service bulletin, a supplemental inspection for disbonds was added as a more
work requirement for airplanes inspected in accordance with the initial release of this service bulletin.
The compliance time for the supplemental disbond inspection added with Revision 1 to this service
bulletin is changed with this revision.
Federal Aviation Administration (FAA) Airworthiness Directives AD 2006-20-02, AD 2006-24-02, and AD
2006-24-05 are related to this service bulletin.
REASON FOR REVISION
This revision is sent to give a revised (later) compliance time for the disbond inspection given in this service
bulletin. Boeing has conducted additional analysis which shows that the initial disbond inspection can be delayed
if crack inspections are accomplished at the intervals specified in this revision.
Also, this revision is sent to give an exemption from the inspections given in this service bulletin to areas where
external modification doublers have been installed in accordance with Boeing Service Bulletin 747-53A2367 .
These areas were inadvertantly omitted from the list of exempt areas given in previous releases of this service
bulletin.
These sections were changed:
1. Paragraph 1.E., Compliance: Changes have been made to the compliance tables as follows:
Table 1: Changed compliance time for initial disbond inspection from 8,000 to 14,000 flight-cycles and
added note (f).
Table 2: Changed compliance time for initial disbond inspection from 8,000 to 14,000 flight-cycles and
added note (h).
Table 3: Changed compliance time for initial disbond inspection from 10,000 to 16,000 flight-cycles and
added note (h).
Tables 4, 5: Removed the action of a disbond inspection so that it is now not a necessary action for any
condition given in these tables.
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Tables 6, 8: Changed compliance time for the supplemental disbond inspection from 8,000 to 14,000
flight-cycles.
Tables 7, 9: Changed compliance time for the supplemental disbond inspection from 10,000 to 16,000
flight-cycles.
2. Paragraph 3.B., Work Instructions:
Step 1: Areas where external modification doublers have been installed in accordance with Boeing Service
Bulletin 747-53A2367  have been added to the list of areas that are exempt from the crack and fastener
inspections given in this service bulletin.
Step 2: Areas where external modification doublers have been installed in accordance with Boeing Service
Bulletin 747-53A2367  have been added to the list of areas that are exempt from the disbond inspections
given in this service bulletin. Also, instruction to inspect for disbonds in areas common to external repair
doublers was removed.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location
of important changes.
Pages with no vertical lines have no important changes.
REVISION HISTORY
July 08, 2010Original Issue:
October 12, 2011Revision 1:
February 22, 2012Revision 2:
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Commercial 
Airplanes
747
Service Bulletin
SummaryNumber: 747-53A2747Original Issue: July 08, 2010
Revision 2: February 22, 2012
ATA System: 5331
SUBJECT: FUSELAGE - Skin - Inspection, Repair and Modification of Section 41 Skin Panels
CONCURRENT REQUIREMENTS
None.
BACKGROUND
This service bulletin tells about the possibility of fatigue cracks in the section 41 body skins caused by disbond
of the internal doublers. Fatigue cracks can start in the body skin at fastener holes where internal doublers have
disbonded from the skin panel. This service bulletin tells how to find and repair disbonded doublers and fatigue
cracks before they can affect flight safety. This service bulletin also tells about the possibility of cracked, deformed,
or missing fastener heads in section 41 and it tells how to find and repair this condition which could cause fatigue
cracking at adjacent fastener holes. Lastly, this service bulletin tells how the structure in section 41 can be
changed so that the inspections given in this service bulletin will not be necessary. Fatigue cracks that are not
found and repaired could extend with continued use of the airplane and cause a rapid decompression and loss
of structural integrity.
The section 41 skin panels to be inspected have internal bonded doublers which reinforce the skin where it is
connected by fasteners to the stringers, frames, intercostals, sills, and shear ties. The function of the internal
bonded doublers is to reduce bending stresses in the skin. If an internal doubler becomes disbonded, the bending
stresses in the skin will increase in the area of the disbond and this can cause fatigue cracks to start at the
fastener holes common to the disbonded doubler.
Boeing Service Bulletins 747-53A2321, 747-53A2409, 747-53A2675 and 747-53A2406 each give instruction to
inspect for skin cracks over some of the inspection area given in this service bulletin. Boeing Service Bulletin
747-53A2409 also gives instruction to inspect some section 41 skin panels for disbonded doublers. Boeing
Service Bulletin 747-53A2409 instructs to do repeat inspections only if/where disbonded doublers were found
with the initial inspection. Based on a report of a disbonded doubler and 10 inch crack found at 21,800 flight-cycles
on an airplane that had been inspected as given in Boeing Service Bulletin 747-53A2409, it is now believed that
certain section 41 skin panels should be inspected for doubler disbond and cracks over the operational life of
the airplane, or until a replacement skin panel is installed.
Boeing has also received two reports of cracked or missing fastener heads found on four airplanes. Cracked
and/or missing fastener heads were found at STA 480 and STA 520 between stringers S-8 and S-10 on airplanes
with 10,529 and 10,531 flight-cycles. Also, missing fastener heads were found between STA 400 and 420 at
stringer S-24AL on airplanes with 28,153 and 28,319 flight-cycles. As a result of these findings, this service
bulletin also includes an inspection for cracked, deformed or missing fastener heads.
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The inspections given in this service bulletin supersede those given in Boeing Service Bulletins 747-53A2321,
747-53A2409, and 747-53A2675. The inspections given in this service bulletin also supersede the section 41
(only) inspections given in Boeing Service Bulletin 747-53A2406. Inspection in accordance with these service
bulletins is to be continued until inspection in accordance with this service bulletin is started.
Boeing Service Related Problem (SRP) 747-SRP-53-0297 is related to this service bulletin (SB).
ACTION
Specified skin panels in section 41 are to be inspected for cracks and disbonded doublers. The skin panels are
to be inspected for cracks at the fasteners common to the frames, stringers, intercostals and shear ties. The
inspection for cracks is to be done from outside the airplane using a specified surface HFEC procedure. Also,
a Detailed inspection for cracked, deformed or missing countersunk fastener heads is to be made in the same
areas inspected for cracks.
The skin panels are also to be inspected for disbonds at the doublers that reinforce the skin where it is fastened
to the frames, stringers, intercostals, shear ties and sills. The disbond inspection is to be done from outside the
airplane using a specified ultrasonic or thermographic procedure, or alternatively, a Detailed inspection for
disbonds can be done from inside the airplane.
Skin panels that have a crack or damaged fastener are to be repaired in accordance with the SRM. Skin panels
that have missing fasteners or fasteners with deformed or missing heads are to be repaired in accordance with
this service bulletin. Where there is a disbond finding and the disbonded area is crack-free, a disbond repair
can be accomplished in accordance with the SRM, or alternatively, only repeat inspections for cracks can be
accomplished. Skin panels that have more than a specified amount of disbond are to be replaced within a
specified number of flight-cycles.
EFFECTIVITY
747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F,
747SP, 747SR Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.
COMPLIANCE
Refer to Paragraph 1.E., Compliance.
Federal Aviation Administration (FAA) Airworthiness Directives FAA AD 2006-24-02, FAA AD 2006-20-02, and
FAA AD 2006-24-05 are related to this service bulletin.
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.
INDUSTRY SUPPORT INFORMATION
Boeing warranty remedies are not available for the inspections and/or repair procedures given in this service
bulletin.
MANPOWER
Refer to Paragraph 1.G., Manpower.
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BOEING SERVICE BULLETIN 747-53A2747
MATERIAL INFORMATION
None.
INSPECT THE SKIN PANELS IN THE SHADED  AREA FOR CRACKS, DISBONDED DOUBLERS, AND
CRACKED, MISSHAPED OR MISSING FASTE  JER HEADS.  INSPECT FOR CRACKS AT THE FASTENERS
COMMON TO THE FRAMES, STRINGERS, INTERCOSTALS AND SHEAR TIES FROM OUTSIDE THE
AIRPLANE USING A SPECIFIED HFEC PROCEDURE.  • FOR DISBONDS AT THE INTERNAL
DOUBLERS THAT REINFORCE THE SKIN WHERE IT  NED TO THE FRAMES, STRINGERS,
INTERCOSTALS, SHEAR TIES AND SILLS. INSPEC  T FOR DISBONDS FROM OUTSIDE THE AIRPLANE
USING A SPECIFIED ULTRASONIC OR THEMOGRAPHIC PROCEDURE, OR ALTERNATIVELY, DO A
DETAILED INSPECTION FOR DISBONDS FROM INSIDE THE AIRPLANE. REPAIR SKIN PANEL CRACKS,
DISBONDS, AND DAMAGED FASTENERS IN ACCORDANCE WITH THE SRM. REPLACE SKIN PANELS
WITHIN A SPECIFIED NUMBER OF FLIGHT-CYCLES IF MORE THAN A SPECIFIED AMOUNT OF DISBOND
IS FOUND ON THE PANELS.
STA
520
STA
340  _S-6
STA  260  _ S-14
STA
220
STA
520
S-10A  000000000  STA  400
S-34  STA
340
~ S-6
S-19-  • 0  STA  260
S-23-  STA  400  STA  460  STA  300  - S-14
PASSENGER AIRPLANE
LEFT SIDE SHOWN, RIGHT SIDE SIMILAR
- S-34
S-19 -
S-23 -
STA
STA  460
400
AIRPLANE WITH NOSE CARGO DOOR  1843133
LEFT SIDE SHOWN, RIGHT SIDE SIMILAR
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Revision 2: February 22, 2012  747-53A2747
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Commercial 
Airplanes
747
Service Bulletin
Number: 747-53A2747
Original Issue: July 08, 2010
Revision 2: February 22, 2012
ATA System: 5331
SUBJECT: FUSELAGE - Skin - Inspection, Repair and Modification of Section 41 Skin Panels
1.    PLANNING INFORMATION
A. Effectivity
1. Airplanes
This service bulletin is for the airplanes shown below.
Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line
Number, and Serial Number data.
DESCRIPTIONCONFIGURATIONGROUP
Line number 1-200 airplanes that do not have a nose cargo door or
Stretched Upper Deck
-1
Line number 201-430 airplanes that do not have a nose cargo door
or Stretched Upper Deck
-2
Line number 431-628 airplanes that do not have a nose cargo door
or stretched upper deck
-3
Line number 686-1075 airplanes that do not have a nose cargo door
or stretched upper deck
-4
Line number 201-430 airplanes that have a stretched upper deck-5
Line number 431-628 airplanes that have a stretched upper deck-6
Line number 686-1075 airplanes that have a stretched upper deck-7
Line number 1-200 airplanes that have a nose cargo door-8
Line number 201-430 airplanes that have a nose cargo door-9
Line number 431-628 airplanes that have a nose cargo door-10
Line number 686-1075 airplanes that have a nose cargo door-11
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DESCRIPTIONCONFIGURATIONGROUP
Line number 629-685 airplanes that do not have a nose cargo door
or stretched upper deck
-12
Line number 629-685 airplanes that have a stretched upper deck-13
Line number 629-685 airplanes that have a nose cargo door-14
Airplane Models:
747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400,
747-400D, 747-400F, 747SP, 747SR
GroupVariable Number
1RA001 - RA034
1RA101 - RA115
1RA161 - RA164
1RA201 - RA203
1RA216 - RA217
1RA245 - RA246
1RA251 - RA259
2RA260 - RA266
1RA301 - RA312
2RA313 - RA318
1RA351 - RA360
1RA369 - RA373
1RA401 - RA414
2RA415 - RA418
1RA501 - RA502
1RA521 - RA527
2RA528
1RA532 - RA540
2RA541 - RA548
1RA551 - RA552
1RA559 - RA561
1RA581 - RA582
1RA585
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GroupVariable Number
1RA601 - RA602
1RA631 - RA635
1RA651 - RA652
1RA671 - RA677
1RA701 - RA702
1RA721 - RA724
2RA725 - RA729
3RA730 - RA731
1RA741 - RA743
2RA744 - RA745
2RA749 - RA750
1RA761 - RA762
1RA781 - RA782
2RA783 - RA784
1RA901 - RA916
1RB001 - RB005
2RB006 - RB016
1RB041 - RB044
1RB071 - RB075
1RB101 - RB102
12RB411 - RB412
4RB413
4RB421
2RB601 - RB607
2RB681 - RB687
3RB688 - RB697
2RB711
2RB721 - RB722
3RB723
3RB741 - RB748
1RD001 - RD002
2RD003 - RD004
2RD021 - RD022
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GroupVariable Number
2RD041 - RD052
3RD053 - RD059
2RD071 - RD072
2RD081
3RD082 - RD083
2RD091 - RD092
2RD101 - RD104
2RD121 - RD124
3RD125 - RD127
2RD131 - RD139
3RD140 - RD144
12RD166 - RD167
2RD171 - RD172
2RD181 - RD183
2RD201 - RD203
3RD204
3RD221 - RD226
12RD227
12RD231 - RD234
4RD235
2RD241
3RD242 - RD243
2RD251 - RD256
3RD257 - RD259
12RD260 - RD262
2RD271 - RD272
12RD291 - RD292
12RD301 - RD302
12RD311
2RD351
3RD352 - RD358
2RD361 - RD363
3RD364 - RD366
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GroupVariable Number
5RD381
6RD382 - RD383
2RD411 - RD413
3RD414
3RD421 - RD426
3RD431 - RD435
3RD441 - RD442
3RD451 - RD456
3RD461
3RD471 - RD475
2RD513 - RD517
3RD518 - RD519
2RD531 - RD532
3RD533
2RD551
2RD561
2RD571
3RD581 - RD583
2RD591 - RD592
3RD593
5RD601 - RD606
6RD607
2RD621 - RD623
2RD641 - RD646
3RD647 - RD649
2RD651 - RD654
3RD655 - RD658
12RD659
2RD661
2RD671
2RD681 - RD682
2RD691 - RD692
2RD701 - RD702
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GroupVariable Number
6RD721 - RD722
3RD741 - RD742
3RD751 - RD754
12RD755
3RD761
3RD771 - RD773
12RD774 - RD775
3RD781 - RD782
12RD783
12RD791
4RD792
3RE001
2RG001 - RG009
2RG091
3RG095
2RG101 - RG104
2RG121 - RG126
2RG141 - RG142
2RG161 - RG162
3RG163 - RG164
2RG171
3RG172 - RG174
2RG191
3RG192 - RG193
3RG211 - RG213
3RG221 - RG222
2RH101
12RH102
3RH111 - RH112
3RH121 - RH122
9RJ131 - RJ133
9RJ151 - RJ152
9RJ301 - RJ302
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GroupVariable Number
10RJ303
14RJ321
11RJ322
9RJ331
10RJ332 - RJ333
9RR001 - RR005
10RR021 - RR023
11RR024 - RR025
9RR031
8RR201
9RR202
10RR203 - RR204
14RR205
11RR206
9RR221 - RR224
10RR225 - RR226
9RR261 - RR262
10RR263 - RR265
14RR266 - RR267
9RR301 - RR304
10RR305 - RR306
11RR307 - RR310
9RR331 - RR332
10RR336
9RR341 - RR344
10RR345
9RR361 - RR362
9RR421
10RR422
14RR431 - RR432
11RR441 - RR442
11RR451
9RR501 - RR502
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GroupVariable Number
10RR503 - RR504
10RR521
11RR522
11RR526
10RR531
10RR551 - RR553
11RR554 - RR556
10RR561
11RR566
11RR701
11RR721 - RR722
11RR746 - RR747
11RR851 - RR854
11RR951 - RR952
13RS001 - RS002
6RS201
6RS211 - RS212
6RS221 - RS222
6RS231 - RS241
6RS251 - RS254
13RS255 - RS258
7RS259
7RS263
7RS265 - RS268
6RS271 - RS273
13RS274 - RS276
6RS291 - RS292
6RS301
13RS302 - RS304
7RS305 - RS306
6RS311 - RS315
13RS316 - RS320
7RS331 - RS333
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GroupVariable Number
13RS341
7RS342
6RS699
6RS701 - RS702
7RS703
6RS711 - RS712
13RS713
6RS721
13RS722
7RS731 - RS732
13RS741 - RS743
13RS751 - RS752
13RS761
7RS762
13RS771
7RS781 - RS782
7RS786
7RT001 - RT011
7RT021 - RT022
7RT031 - RT033
7RT041 - RT047
7RT061
7RT071 - RT075
7RT101 - RT103
7RT121
7RT131 - RT134
7RT151 - RT152
7RT161 - RT166
7RT401 - RT412
7RT431 - RT441
7RT451 - RT469
7RT471 - RT499
7RT501 - RT535
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GroupVariable Number
7RT551 - RT568
7RT571 - RT588
7RT591
7RT601 - RT622
7RT631 - RT636
7RT641 - RT657
7RT671 - RT673
7RT681 - RT682
7RT691 - RT699
7RT701 - RT704
7RT711 - RT717
7RT741 - RT755
7RT776 - RT777
7RT781 - RT784
7RT831 - RT833
7RT861 - RT864
7RT876 - RT880
7RT931 - RT932
7RT945 - RT946
7RT951 - RT954
7RT966 - RT967
7RU001 - RU004
7RU031 - RU032
7RU051 - RU052
7RU059 - RU062
7RU081 - RU083
7RU121 - RU123
7RU801 - RU809
7RU831 - RU841
2. Spares Affected
None.
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B. Concurrent Requirements
None.
C. Reason
This service bulletin tells about the possibility of fatigue cracks in the section 41 body skins caused by
disbond of the internal doublers. Fatigue cracks can start in the body skin at fastener holes where
internal doublers have disbonded from the skin panel. This service bulletin tells how to find and repair
disbonded doublers and fatigue cracks before they can affect flight safety. This service bulletin also
tells about the possibility of cracked, deformed, or missing fastener heads in section 41 and it tells how
to find and repair this condition which could cause fatigue cracking at adjacent fastener holes. Lastly,
this service bulletin tells how the structure in section 41 can be changed so that the inspections given
in this service bulletin will not be necessary. Fatigue cracks that are not found and repaired could extend
with continued use of the airplane and cause a rapid decompression and loss of structural integrity.
The section 41 skin panels to be inspected have internal bonded doublers which reinforce the skin
where it is connected by fasteners to the stringers, frames, intercostals, sills, and shear ties. The
function of the internal bonded doublers is to reduce bending stresses in the skin. If an internal doubler
becomes disbonded, the bending stresses in the skin will increase in the area of the disbond and this
can cause fatigue cracks to start at the fastener holes common to the disbonded doubler.
Boeing Service Bulletins 747-53A2321, 747-53A2409, 747-53A2406, and 747-53A2675 each give
instruction to inspect for skin cracks over some of the inspection area given in this service bulletin.
Boeing Service Bulletin 747-53A2409 also gives instruction to inspect some section 41 skin panels for
disbonded doublers. Boeing Service Bulletin 747-53A2409 instructs to do repeat inspections only
if/where disbonded doublers were found with the initial inspection. Based on a report of a disbonded
doubler and 10 inch crack found at 21,800 flight-cycles on an airplane that had been inspected as given
in Boeing Service Bulletin 747-53A2409, it is now believed that certain section 41 skin panels should
be inspected for doubler disbond and cracks over the operational life of the airplane, or until a
replacement skin panel is installed.
Boeing also has received two reports of cracked or missing fastener heads found on four airplanes.
Cracked and/or missing fastener heads were found at STA 480 and STA 520 between stringers S-8
and S-10 on airplanes with 10,529 and 10,531 flight-cycles. Also, missing fastener heads were found
between STA 400 and 420 at stringer S-24AL on airplanes with 28,153 and 28,319 flight-cycles. As a
result of these findings, this service bulletin also includes an inspection for cracked, deformed, or
missing fastener heads
The inspections given in this service bulletin supersede those given in Boeing Service Bulletins
747-53A2321, 747-53A2409, and 747-53A2675. The inspections given in this service bulletin also
supersede the section 41 (only) inspections given in Boeing Service Bulletin 747-53A2406. Inspection
in accordance with these service bulletins is to be continued until inspection in accordance with this
service bulletin is started.
Boeing Service Related Problem (SRP) 747-SRP-53-0297 is related to this service bulletin (SB).
Revision 1 is sent to give a changed compliance time limit for the initial inspections and to remove the
compliance time for disbond repairs. With Revision 1, the repair of disbonds became an optional task
where the disbonded area is crack-free. With Revision 1 the total inspection area was divided into two
areas labeled Zone 1 and Zone 2 due to differences in the compliance data for the two Zones. Also,
Revision 1 adds doubler locations to the disbond inspection given in this service bulletin.
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Revision 2 is sent to give a revised (later) compliance time for the disbond inspection given in this
service bulletin. Also, Revision 2 is sent to give an exemption from the inspections given in this service
bulletin to areas where external modification doublers have been installed in accordance with Boeing
Service Bulletin 747-53A2367 .
D. Description
Specified skin panels in section 41 are to be inspected for cracks and disbonded doublers. The skin
panels are to be inspected for cracks at the fasteners common to the frames, stringers, intercostals
and shear ties. The inspection for cracks is to be done from outside the airplane using a specified
surface HFEC procedure. Also, a Detailed inspection for cracked, deformed or missing countersunk
fastener heads is to be made in the same areas inspected for cracks.
The skin panels are also to be inspected for disbonds at the doublers that reinforce the skin where it
is fastened to the frames, stringers, intercostals, shear ties and sills. The disbond inspection is to be
done from outside the airplane using a specified ultrasonic or thermographic procedure, or alternatively,
a Detailed inspection for disbonds can be done from inside the airplane.
Skin panels that have a crack or damaged fastener are to be repaired in accordance with the SRM.
Skin panels that have missing fasteners or fasteners with deformed or missing heads are to be repaired
in accordance with this service bulletin. Where there is a disbond finding and the disbonded area is
crack-free, a disbond repair can be accomplished in accordance with the SRM, or alternatively, only
repeat inspections for cracks can be accomplished. Skin panels that have more than a specified amount
of disbond are to be replaced within a specified number of flight-cycles.
The changes in this service bulletin will not change the Central Maintenance Computer System (CMCS).
Revision 1 - More work is necessary on airplanes inspected in accordance with the original issue of
this service bulletin. A supplemental inspection for disbonds is necessary at doubler locations on each
side of the airplane. These doubler locations were added to the disbond inspection given in this service
bulletin with this revision.
Revision 2 - No more work is necessary on the airplane(s) changed in accordance with Revision 1 of
this service bulletin. The compliance time for the supplemental disbond inspection (the more work
requirement associated with Revision 1 of this service bulletin) is changed with this revision.
The work in this service bulletin is done in the maintenance zone(s) given below.
Group 1:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-100, 747-200B
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Group 2:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-100, 747-100B, 747-200B,
747SP, 747SR
Group 3:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-100B, 747-200B, 747SP,
747SR
Group 4-5:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200B
Group 6:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200B, 747-300
Group 7:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-300, 747-400, 747-400D
Group 8:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200F
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Group 9-10, 14:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200C, 747-200F
Group 11:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200C, 747-200F, 747-400F
Group 12:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-200B, 747SP
Group 13:
Affected Maintenance Zones
ZoneModel
112, 115, 116, 117, 118, 121, 122, 211, 212,
221, 222, 223, 224, 231, 232
747-100B SUD, 747-300
E. Compliance
Federal Aviation Administration (FAA) Airworthiness Directives FAA AD 2006-24-02, FAA AD 2006-20-02,
and FAA AD 2006-24-05 are related to this service bulletin.
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.
NOTE: If a Condition given in a Compliance Table is applicable (the criteria for that Condition is
satisfied by the actual conditions), then the Action given in the table with that Condition is
necessary regardless of whether there is another applicable Condition in the table with a
different Action.
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Group 1-2, 5, 8-9:
Table 1: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.
(b)
Before 8,000 total
flight cycles, or
within 2,000 flight
cycles after doing
an HFEC inspec-
tion in accordance
with Boeing Ser-
vice Bulletin 747-
53A2675, or within
150 flight cycles
after the original is-
sue date of this
service bulletin,
whichever occurs
latest.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have had a
HFEC inspection in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin.
2,000 flight-cycles.
(b)
Before 8,000 total
flight-cycles, or
within 150 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have NOT
had a HFEC inspection in
accordance with service
bulletin 747-53A2675 as of
the original issue date of
this service bulletin.
2,000 flight-cycles.
(b)
Before 8,000 total
flight-cycles, or
within 2,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
All airplanes.
See Table 4 for applicable data.All airplanes: an external
or internal repair doubler
has been installed at the
inspection area and the
fasteners common to the
inspection area are the
edge row fasteners through
the repair doubler, or the
second or third row of fas-
teners from the edge of the
repair doubler.
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### Page 26

Group 1-2, 5, 8-9:
Table 1: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 14,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last. (f)
In inspection Zone 1 and
Zone 2:
Do an external or internal
inspection for disbonded
doublers in accordance
with Paragraph 3.B.,
Work Instructions. (a)
All airplanes:
-Before further
flight.
Accomplish a repair in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin crack or discrepant
fastener finding.
(d)
(b)
6,000 flight-cycles.Within 6,000 flight-
cycles after the ini-
tial inspection of
the skin panel for
disbonds.
Repeat the inspection for
disbonded doublers in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has no disbond
or has less than 50% dis-
bond.
(c) (g)
(b) (e)
(b) (e)
-Within 6,000 flight-
cycles of the dis-
bond inspection
where disbond was
found to be 50% or
more.
Replace the skin panel in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has 50% or
more disbond.
(c) (g)
--No more work is neces-
sary at the replacement
skin panel.
Skin panel has been re-
placed in accordance with
this service bulletin.
(a) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
(b) A replacement skin panel can be installed as an alternative to doing SRM repairs and/or
repeat inspections.
(c) The % disbond is the sum of the disbonded areas on the skin panel divided by the sum
of the areas of all the internal bonded doublers on the skin panel. The sum of the disbonded
areas includes all disbonded areas that have been found on the skin panel including those
associated with previous findings and those associated with the repair area disbond in-
spections given in Table 4. If the amount of disbonded area for any given internal doubler
associated with a previous repair is not known, it is to be assumed that the doubler was
fully (100%) disbonded.
(d) Discrepant fasteners include those with a crack or other damage including a deformed or
missing head.
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### Page 27

Group 1-2, 5, 8-9:
Table 1: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
(e) Repair of a disbonded doubler in accordance with Paragraph 3.B., Work Instructions is
terminating action for the disbond inspection at the repaired location.
(f) If the airplane was inspected for disbonds in accordance with the initial release of this
service bulletin and not inspected for disbonds in accordance with a later revision of this
service bulletin, the supplemental disbond inspection data given in Compliance Table 6
(Groups 1, 2, 5) or Table 8 (Groups 8, 9) is applicable.
(g) Repeat inspections for cracks and discrepant fasteners as specified in this table above
are also applicable with this condition.
Group 3, 6, 10, 12-14:
Table 2: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 8,000 total
flight cycles, or
within 2,000 flight
cycles after doing
an HFEC inspec-
tion in accordance
with Boeing Ser-
vice Bulletin 747-
53A2675, or within
150 flight cycles
after the original is-
sue date of this
service bulletin,
whichever occurs
latest.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have had a
HFEC inspection in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin.
-Before 8,000 total
flight-cycles, or
within 150 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have NOT
had a HFEC inspection in
accordance with service
bulletin 747-53A2675 as of
the original issue date of
this service bulletin.
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### Page 28

Group 3, 6, 10, 12-14:
Table 2: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 8,000 total
flight-cycles, or
within 2,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
All airplanes.
See Table 4 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
-Before further
flight.
Accomplish a repair in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin crack or discrepant
fastener finding.
(d)
(b)
-Before 14,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 1 and
Zone 2:
Do an external or internal
inspection for disbonded
doublers in accordance
with Paragraph 3.B.,
Work Instructions. (a)
All Airplanes.
6,000 flight-cycles.Within 6,000 flight-
cycles after the ini-
tial inspection of
the skin panel for
cracks.
Repeat the inspection for
skin cracks and the in-
spection for discrepant
fasteners in accordance
with Paragraph 3.B.,
Work Instructions.
Skin panel HAS been in-
spected for disbonds and
the skin panel has no new
or previous crack or dis-
bond finding.
(e) (g) (h)
(b)
(b) (d)
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### Page 29

Group 3, 6, 10, 12-14:
Table 2: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.Within 2,000 flight-
cycles after the ini-
tial inspection of
the skin panel for
cracks.
Repeat the inspection for
skin cracks and the in-
spection for discrepant
fasteners in accordance
with Paragraph 3.B.,
Work Instructions.
Skin panel has NOT been
inspected for disbonds, or
skin panel has a new or
previous crack or disbond
finding. (i)
(b)
(b) (d)
6,000 flight-cycles.Within 6,000 flight-
cycles after the ini-
tial inspection of
the skin panel for
disbonds.
Repeat the inspection for
disbonded doublers in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has no disbond
or has less than 50% dis-
bond.
(c) (j)
(b) (f)
(b) (f)
-Within 6,000 flight-
cycles of the dis-
bond inspection
where disbond was
found to be 50% or
more.
Replace the skin panel in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has 50% or
more disbond.
(c) (j)
--No more work is neces-
sary at the replacement
skin panel.
Skin panel has been re-
placed in accordance with
this service bulletin.
(a) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
(b) A replacement skin panel can be installed as an alternative to doing SRM repairs and/or
repeat inspections.
(c) The % disbond is the sum of the disbonded areas on the skin panel divided by the sum
of the areas of all the internal bonded doublers on the skin panel. The sum of the disbonded
areas includes all disbonded areas that have been found on the skin panel including those
associated with previous findings and those associated with the repair area disbond in-
spections given in Table 4. If the amount of disbonded area for any given internal doubler
associated with a previous repair is not known, it is to be assumed that the doubler was
fully (100%) disbonded.
(d) Discrepant fasteners include those with a crack or other damage including a deformed or
missing head.
(e) The results from crack inspections at repair locations accomplished in accordance with
Table 4 are to be included in the determination of the applicable condition.
(f) Repair of a disbonded doubler in accordance with Paragraph 3.B., Work Instructions is
terminating action for the disbond inspection at the repaired location.
(g) If the skin panel was inspected for disbonds in accordance with the initial release of this
service bulletin and not inspected for disbonds in accordance with a later revision of this
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### Page 30

Group 3, 6, 10, 12-14:
Table 2: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
service bulletin, the supplemental disbond inspection data given in Compliance Table 6
(Groups 3, 6, 12, 13) or Table 8 (Groups 10, 14) is applicable and the supplemental disbond
inspection must be accomplished for a no disbond condition to apply to the skin panel.
(h) The compliance time for the repeat inspection for cracks and discrepant fasteners is de-
pendent on whether or not a crack or disbond has been found on the skin panel. In addition
to the repeat inspections for cracks and discrepant fasteners given with this condition,
repeat inspections for disbonds (or skin panel replacement) as specified in this table below
are also applicable with this condition.
(i) The compliance time for the repeat inspection for cracks and discrepant fasteners is de-
pendent on whether or not a crack or disbond has been found on the skin panel. In addition
to the repeat inspections for cracks and discrepant fasteners given with this condition,
repeat inspections for disbonds (or skin panel replacement) as specified in this table below
are also applicable (after the initial disbond inspection is accomplished).
(j) Repeat inspections for cracks and discrepant fasteners as specified in this table above
are also applicable with this condition.
Group 4, 7, 11:
Table 3: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 10,000 total
flight cycles, or
within 2,000 flight
cycles after doing
an HFEC inspec-
tion in accordance
with Boeing Ser-
vice Bulletin 747-
53A2675, or within
150 flight cycles
after the original is-
sue date of this
service bulletin,
whichever occurs
latest.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have had a
HFEC inspection in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin.
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### Page 31

Group 4, 7, 11:
Table 3: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 10,000 total
flight-cycles, or
within 150 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
Airplanes that have NOT
had a HFEC inspection in
accordance with service
bulletin 747-53A2675 as of
the original issue date of
this service bulletin.
-Before 10,000 total
flight-cycles, or
within 2,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks and an external
Detailed inspection for
discrepant fasteners in
accordance with Para-
graph 3.B., Work Instruc-
tions. (d)
All airplanes.
See Table 5 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
-Before further
flight.
Accomplish a repair in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin crack or discrepant
fastener finding.
(d)
(b)
-Before 16,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
In inspection Zone 1 and
Zone 2:
Do an external or internal
inspection for disbonded
doublers in accordance
with Paragraph 3.B.,
Work Instructions. (a)
All airplanes.
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### Page 32

Group 4, 7, 11:
Table 3: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
6,000 flight-cycles.Within 6,000 flight-
cycles after the ini-
tial crack inspec-
tion.
Repeat the inspection for
skin cracks and the in-
spection for discrepant
fasteners in accordance
with Paragraph 3.B.,
Work Instructions.
Skin panel HAS been in-
spected for disbonds and
the skin panel has no new
or previous crack or dis-
bond finding.
(e) (g) (h)
(b)
(b) (d)
2,000 flight-cycles.Within 2,000 flight-
cycles after the ini-
tial crack inspec-
tion.
Repeat the inspection for
skin cracks and the in-
spection for discrepant
fasteners in accordance
with Paragraph 3.B.,
Work Instructions.
Skin panel has NOT been
inspected for disbonds, or
skin panel has a new or
previous crack or disbond
finding. (i)
(b)
(b) (d)
6,000 flight-cycles.Within 6,000 flight-
cycles after the ini-
tial disbond inspec-
tion.
Repeat the inspection for
disbonded doublers in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has no disbond
or has less than 50% dis-
bond.
(c) (j)
(b) (f)
(b) (f)
-Within 6,000 flight-
cycles of the dis-
bond inspection
where disbond was
found to be 50% or
more.
Replace the skin panel in
accordance with Para-
graph 3.B., Work Instruc-
tions.
Skin panel has 50% or
more disbond.
(c) (j)
--No more work is neces-
sary at the replacement
skin panel.
Skin panel has been re-
placed in accordance with
this service bulletin.
(a) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
(b) A replacement skin panel can be installed as an alternative to doing SRM repairs and/or
repeat inspections.
(c) The % disbond is the sum of the disbonded areas on the skin panel divided by the sum
of the areas of all the internal bonded doublers on the skin panel. The sum of the disbonded
areas includes all disbonded areas that have been found on the skin panel including those
associated with previous findings and those associated with the repair area disbond in-
spections given in Table 5. If the amount of disbonded area for any given internal doubler
associated with a previous repair is not known, it is to be assumed that the doubler was
fully (100%) disbonded.
(d) Discrepant fasteners include those with a crack or other damage including a deformed or
missing head.
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### Page 33

Group 4, 7, 11:
Table 3: Skin Panel Inspection and Repair Compliance Times
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
(e) The results from crack inspections at repair locations accomplished in accordance with
Table 5 are to be included in the determination of the applicable condition.
(f) Repair of a disbonded doubler in accordance with Paragraph 3.B., Work Instructions is
terminating action for the disbond inspection at the repaired location.
(g) If the skin panel was inspected for disbonds in accordance with the initial release of this
service bulletin and not inspected for disbonds in accordance with a later revision of this
service bulletin, the supplemental disbond inspection data given in Compliance Table 7
(Groups 4, 7) or Table 9 (Group 11) is applicable and the supplemental disbond inspection
must be accomplished for a no disbond condition to apply to the skin panel.
(h) The compliance time for the repeat inspection for cracks and discrepant fasteners is de-
pendent on whether or not a crack or disbond has been found on the skin panel. In addition
to the repeat inspections for cracks and discrepant fasteners given with this condition,
repeat inspections for disbonds (or skin panel replacement) as specified in this table below
are also applicable with this condition.
(i) The compliance time for the repeat inspection for cracks and discrepant fasteners is de-
pendent on whether or not a crack or disbond has been found on the skin panel. In addition
to the repeat inspections for cracks and discrepant fasteners given with this condition,
repeat inspections for disbonds (or skin panel replacement) as specified in this table below
are also applicable (after the initial disbond inspection is accomplished).
(j) Repeat inspections for cracks and discrepant fasteners as specified in this table above
are also applicable with this condition.
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### Page 34

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
been inspected in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
8,000 flight-cycles
after the repair
doubler was in-
stalled, or,
the time for the
next repeat inspec-
tion per service
bulletin 747-
53A2675, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
NOT been inspected in ac-
cordance with service bul-
letin 747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
8,000 flight-cycles
after the repair
doubler was in-
stalled, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
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### Page 35

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
All airplanes:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
8,000 flight-cycles
after the repair
doubler was in-
stalled, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial LFEC inspec-
tion accomplished
in accordance with
this service bul-
letin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area and
also an inspection for
disbond of the internal
doubler. Replace the ex-
isting external repair dou-
bler with a new extended
external repair doubler.
Do this work in accor-
dance with Paragraph
3.B., Work Instructions.
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
been inspected in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
8,000 total flight-
cycles, or,
the time for the
next repeat inspec-
tion per service
bulletin 747-
53A2675, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
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### Page 36

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
NOT been inspected in ac-
cordance with service bul-
letin 747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
8,000 total flight-
cycles, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
500 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
All airplanes:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial LFEC inspec-
tion accomplished
in accordance with
this service bul-
letin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area and
also an inspection for
disbond of the internal
doubler. Replace the ex-
isting external repair dou-
bler with a new extended
external repair doubler.
Do this work in accor-
dance with Paragraph
3.B., Work Instructions.
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### Page 37

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
An INTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
8,000 flight-cycles
after the repair
doubler was in-
stalled, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a) 2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
8,000 flight-cycles
after the repair
doubler was in-
stalled, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area.
Replace the existing inter-
nal repair doubler with a
new extended repair
doubler. Do this work in
accordance with Para-
graph 3.B., Work Instruc-
tions.
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BOEING SERVICE BULLETIN 747-53A2747

### Page 38

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
8,000 total flight-
cycles, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
(a)
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area.
Replace the existing inter-
nal repair doubler with a
new extended repair
doubler. Do this work in
accordance with Para-
graph 3.B., Work Instruc-
tions.
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BOEING SERVICE BULLETIN 747-53A2747

### Page 39

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
--Inspection in accordance
with this service bulletin
is not necessary in the
area covered by the re-
pair doubler.
An EXTERNAL or INTER-
NAL repair doubler has
been installed at the inspec-
tion area and the SECOND
row of fasteners from the
edge of the repair doubler
are common to the inspec-
tion area - and an open
hole HFEC inspection of
the skin was accomplished
at the fastener holes com-
mon to the inspection area
at the time of repair or lat-
er.
-Before the last to
occur of:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions.
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
SECOND row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.(c)
-Within 10,000
flight-cycles after
the LFEC inspec-
tion was accom-
plished in accor-
dance with this
service bulletin.
Accomplish the terminat-
ing inspection which in-
cludes an open hole
HFEC inspection for skin
cracks at the fastener
holes common to the in-
spection area and an in-
spection for disbond of
the internal doubler. Ac-
complish these inspec-
tions in accordance with
Paragraph 3.B., Work In-
structions.
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BOEING SERVICE BULLETIN 747-53A2747

### Page 40

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before the last to
occur of:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions.
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
SECOND row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin(c)
-Within 10,000
flight-cycles after
the surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
Accomplish the terminat-
ing inspection which in-
cludes an open hole
HFEC inspection for skin
cracks at the fastener
holes common to the in-
spection area. Accom-
plish this inspection in
accordance with Para-
graph 3.B., Work Instruc-
tions.
--Inspection in accordance
with this service bulletin
is not necessary in the
area covered by the re-
pair doubler.
An EXTERNAL or INTER-
NAL repair doubler has
been installed at the inspec-
tion area and the THIRD
row of fasteners from the
edge of the repair doubler
are common to the inspec-
tion area - and an open
hole HFEC inspection of
the skin was accomplished
at the fastener holes com-
mon to the inspection area
at the time of repair or lat-
er.
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BOEING SERVICE BULLETIN 747-53A2747

### Page 41

Group 1-3, 5-6, 8-10, 12-14:
Table 4: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before the last to
occur of:
Accomplish a one time
external surface LFEC
inspection for skin cracks
at the fasteners common
to the inspection area in
accordance with Para-
graph 3.B., Work Instruc-
tions.
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
THIRD row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Before the last to
occur of:
Accomplish a one time
external surface HFEC
inspection for skin cracks
at the fasteners common
to the inspection area in
accordance with Para-
graph 3.B., Work Instruc-
tions.
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
THIRD row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
8,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Before further
flight.
Accomplish a new repair
in accordance with Para-
graph 3.B., Work Instruc-
tions
Skin crack finding.
(a) To zero-time a fastener hole, an open hole HFEC inspection with no crack finding is ac-
complished and then the hole diameter is increased by 1/16 inch or more to remove any
undetected crack in the skin. If the total flight-cycles on the airplane at the time the repair
doubler was installed is not known, use the compliance time given for a repair that does
not include zero-timed fastener holes.
(b) Accomplishment of the terminating repair is an alternative to this action.
(c) Accomplishment of the terminating inspection is an alternative to this action.
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BOEING SERVICE BULLETIN 747-53A2747

### Page 42

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
been inspected in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
10,000 flight-cycles
after the repair
doubler was in-
stalled, or,
the time for the
next repeat inspec-
tion per service
bulletin 747-
53A2675, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
NOT been inspected in ac-
cordance with service bul-
letin 747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
10,000 flight-cycles
after the repair
doubler was in-
stalled, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
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BOEING SERVICE BULLETIN 747-53A2747

### Page 43

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
All airplanes:
An EXTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
10,000 flight-cycles
after the repair
doubler was in-
stalled, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial LFEC inspec-
tion accomplished
in accordance with
this service bul-
letin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area and
also an inspection for
disbond of the internal
doubler. Replace the ex-
isting external repair dou-
bler with a new extended
external repair doubler.
Do this work in accor-
dance with Paragraph
3.B., Work Instructions.
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
been inspected in accor-
dance with service bulletin
747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
10,000 total flight-
cycles, or,
the time for the
next repeat inspec-
tion per service
bulletin 747-
53A2675, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
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### Page 44

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
500 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
For airplanes that have
NOT been inspected in ac-
cordance with service bul-
letin 747-53A2675 as of the
original issue date of this
service bulletin:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
10,000 total flight-
cycles, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a)
500 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions. (b)
All airplanes:
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial LFEC inspec-
tion accomplished
in accordance with
this service bul-
letin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area and
also an inspection for
disbond of the internal
doubler. Replace the ex-
isting external repair dou-
bler with a new extended
external repair doubler.
Do this work in accor-
dance with Paragraph
3.B., Work Instructions.
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### Page 45

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
An INTERNAL repair dou-
bler has been installed at
the inspection area, and
the edge row fasteners
through the repair doubler
are common to the inspec-
tion area - and the edge
row fastener holes were
zero-timed at the time of
repair or later.
10,000 flight-cycles
after the repair
doubler was in-
stalled, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
(a) 2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
10,000 flight-cycles
after the repair
doubler was in-
stalled, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area.
Replace the existing inter-
nal repair doubler with a
new extended repair
doubler. Do this work in
accordance with Para-
graph 3.B., Work Instruc-
tions.
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### Page 46

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 1:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
edge row fasteners through
the repair doubler are
common to the inspection
area - and the edge row
fastener holes were NOT
zero-timed at the time of
repair or later.
10,000 total flight-
cycles, or,
150 flight-cycles
after the original is-
sue date of this
service bulletin.
2,000 flight-cycles.Before the last to
occur of:
In inspection Zone 2:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area. Do this inspection
in accordance with Para-
graph 3.B., Work Instruc-
tions. (b)
(a)
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Within 6,000 flight-
cycles after the ini-
tial surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
In inspection Zone 1 and
Zone 2:
Accomplish a terminating
repair which includes an
open hole HFEC inspec-
tion for skin cracks at the
fastener holes common
to the inspection area.
Replace the existing inter-
nal repair doubler with a
new extended repair
doubler. Do this work in
accordance with Para-
graph 3.B., Work Instruc-
tions.
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### Page 47

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
--Inspection in accordance
with this service bulletin
is not necessary in the
area covered by the re-
pair doubler.
An EXTERNAL or INTER-
NAL repair doubler has
been installed at the inspec-
tion area and the SECOND
row of fasteners from the
edge of the repair doubler
are common to the inspec-
tion area - and an open
hole HFEC inspection of
the skin was accomplished
at the fastener holes com-
mon to the inspection area
at the time of repair or lat-
er.
-Before the last to
occur of:
Do an external surface
LFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions.
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
SECOND row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.(c)
-Within 10,000
flight-cycles after
the LFEC inspec-
tion was accom-
plished in accor-
dance with this
service bulletin.
Accomplish the terminat-
ing inspection which in-
cludes an open hole
HFEC inspection at the
fastener holes common
to the inspection area and
an inspection for disbond
of the internal doubler.
Accomplish these inspec-
tions in accordance with
Paragraph 3.B., Work In-
structions.
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### Page 48

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before the last to
occur of:
Do an external surface
HFEC inspection for skin
cracks at the fasteners
common to the inspection
area in accordance with
Paragraph 3.B., Work In-
structions.
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
SECOND row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin(c)
-Within 10,000
flight-cycles after
the surface HFEC
inspection accom-
plished in accor-
dance with this
service bulletin.
Accomplish the terminat-
ing inspection which in-
cludes an open hole
HFEC inspection at the
fastener holes common
to the inspection area in
accordance with Para-
graph 3.B., Work Instruc-
tions.
--Inspection in accordance
with this service bulletin
is not necessary in the
area covered by the re-
pair doubler.
An EXTERNAL or INTER-
NAL repair doubler has
been installed at the inspec-
tion area and the THIRD
row of fasteners from the
edge of the repair doubler
are common to the inspec-
tion area - and an open
hole HFEC inspection of
the skin was accomplished
at the fastener holes com-
mon to the inspection area
at the time of repair or lat-
er.
-Before the last to
occur of:
Accomplish a one time
external surface LFEC
inspection for skin cracks
at the fasteners common
to the inspection area in
accordance with Para-
graph 3.B., Work Instruc-
tions.
An EXTERNAL repair dou-
bler has been installed at
the inspection area and the
THIRD row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
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### Page 49

Group 4, 7, 11:
Table 5: Compliance Times for Work Necessary at External and Internal Repairs
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before the last to
occur of:
Accomplish a one time
external surface HFEC
inspection for skin cracks
at the fasteners common
to the inspection area in
accordance with Para-
graph 3.B., Work Instruc-
tions.
An INTERNAL repair dou-
bler has been installed at
the inspection area and the
THIRD row of fasteners
from the edge of the repair
doubler are common to the
inspection area - and an
open hole HFEC inspection
of the skin was NOT accom-
plished at the fastener
holes common to the in-
spection area at the time of
repair or later.
10,000 total flight-
cycles, or,
2,000 flight-cycles
after the original is-
sue date of this
service bulletin.
-Before further
flight.
Accomplish a new repair
in accordance with Para-
graph 3.B., Work Instruc-
tions
Skin crack finding.
(a) To zero-time a fastener hole, an open hole HFEC inspection with no crack finding is ac-
complished and then the hole diameter is increased by 1/16 inch or more to remove any
undetected crack in the skin. If the total flight-cycles on the airplane at the time the repair
doubler was installed is not known, use the compliance time given for a repair that does
not include zero-timed fastener holes.
(b) Accomplishment of the terminating repair is an alternative to this action.
(c) Accomplishment of the terminating inspection is an alternative to this action.
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### Page 50

Group 1-3, 5-6, 12-13:
Table 6: Compliance Time for Supplemental Inspection for Disbonded Doubler
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 14,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
Do an external or internal
supplemental inspection
for disbonds at one inter-
nal doubler location on
each side of the airplane
in accordance with Para-
graph 3.B., Work Instruc-
tions. (a) (b)
Airplanes inspected in ac-
cordance with the initial re-
lease of this service bul-
letin, but not inspected in
accordance with a subse-
quent release of this ser-
vice bulletin.
See Table 4 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
--Refer to Tables 1-2, 4 as
applicable for repair and
reinspection data based
on the results of the sup-
plemental inspection.
Supplemental inspection
for disbonds accomplished.
(a) This supplemental inspection is the "more work" requirement associated with Revision 1
to this service bulletin. The supplemental inspection is at bonded doublers that were not
included in the inspection given in the original release of this service bulletin. The supple-
mental inspection is applicable only to airplanes for which the specified condition applies.
(b) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
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### Page 51

Group 4, 7:
Table 7: Compliance Time for Supplemental Inspection for Disbonded Doubler
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 16,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
Do an external or internal
supplemental inspection
for disbonds at one inter-
nal doubler location on
each side of the airplane
in accordance with Para-
graph 3.B., Work Instruc-
tions. (a) (b)
Airplanes inspected in ac-
cordance with the initial re-
lease of this service bul-
letin, but not inspected in
accordance with a subse-
quent release of this ser-
vice bulletin.
See Table 5 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
--Refer to Tables 3, 5 as
applicable for repair and
reinspection data based
on the results of the sup-
plemental inspection.
Supplemental inspection
for disbonds accomplished.
(a) This supplemental inspection is the "more work" requirement associated with Revision 1
to this service bulletin. The supplemental inspection is at bonded doublers that were not
included in the inspection given in the original release of this service bulletin. The supple-
mental inspection is applicable only to airplanes for which the specified condition applies.
(b) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
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### Page 52

Group 8-10, 14:
Table 8: Compliance Time for Supplemental Inspection for Disbonded Doublers
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 14,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
Do an external or internal
supplemental inspection
for disbonds at internal
doubler locations on the
right side of the airplane
in accordance with Para-
graph 3.B., Work Instruc-
tions. (a) (b)
Airplanes inspected in ac-
cordance with the initial re-
lease of this service bul-
letin, but not inspected in
accordance with a subse-
quent release of this ser-
vice bulletin.
See Table 4 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
--Refer to Tables 1, 2, 4 as
applicable for repair and
reinspection data based
on the results of the sup-
plemental inspection.
Supplemental inspection
for disbonds accomplished.
(a) This supplemental inspection is the "more work" requirement associated with Revision 1
to this service bulletin. The doublers to be inspected with this supplemental inspection
were not identified as doublers to be inspected in the original release of this service bulletin;
however, these doublers were identified as doublers to be inspected in the Ultrasonic in-
spection procedure specified in the initial release of this service bulletin. This supplemental
inspection is necessary only if the doublers included in the supplemental inspection were
not inspected for disbonds when the disbond inspection was accomplished in accordance
with the initial release of this service bulletin.
(b) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
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### Page 53

Group 11:
Table 9: Compliance Time for Supplemental Inspection for Disbonded Doublers
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before 16,000 total
flight-cycles, or
within 6,000 flight-
cycles after the
original issue date
of this service bul-
letin, whichever
occurs last.
Do an external or internal
supplemental inspection
for disbonds at internal
doubler locations on the
right side of the airplane
in accordance with Para-
graph 3.B., Work Instruc-
tions. (a) (b)
Airplanes inspected in ac-
cordance with the initial re-
lease of this service bul-
letin, but not inspected in
accordance with a subse-
quent release of this ser-
vice bulletin.
See Table 5 for applicable data.An external or internal re-
pair doubler has been in-
stalled at the inspection
area and the fasteners
common to the inspection
area are the edge row fas-
teners through the repair
doubler, or the second or
third row of fasteners from
the edge of the repair dou-
bler.
--Refer to Tables 3, 5 as
applicable for repair and
reinspection data based
on the results of the sup-
plemental inspection.
Supplemental inspection
for disbonds accomplished.
(a) This supplemental inspection is the "more work" requirement associated with Revision 1
to this service bulletin. The doublers to be inspected with this supplemental inspection
were not identified as doublers to be inspected in the original release of this service bulletin;
however, these doublers were identified as doublers to be inspected in the Ultrasonic in-
spection procedure specified in the initial release of this service bulletin. This supplemental
inspection is necessary only if the doublers included in the supplemental inspection were
not inspected for disbonds when the disbond inspection was accomplished in accordance
with the initial release of this service bulletin.
(b) The alternatives for the disbond inspection are: external ultrasonic, external thermography,
and internal detailed.
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.
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### Page 54

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.
The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the inspection and corrective
actions of SB 747-53A2747, Revision 2 as an AMOC to the inspection and repair required by paragraphs
(f), (k), and (l) of FAA AD 2006-24-02. When this SB specifies contacting Boeing for repair instructions,
the repair instructions must be approved by the FAA in accordance with paragraph (n) of the FAA AD.
All provisions of FAA AD 2006-24-02 that are not specifically referenced in this paragraph remain fully
applicable and must be complied with.
The Manager of the FAA Seattle Aircraft Certification Office (ACO) also approves the inspection and
corrective actions of SB 747-53A2747, Revision 2 as an AMOC to the inspection, investigative and
corrective actions required by paragraphs (f), (g), and (h) of FAA AD 2006-20-02. When this SB specifies
contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in
accordance with paragraph (k) of the FAA AD. All provisions of FAA AD 2006-20-02 that are not
specifically referenced in this paragraph remain fully applicable and must be complied with.
The Manager of the FAA Seattle Aircraft Certification Office (ACO) also approves the inspection and
corrective actions of SB 747-53A2747, Revision 2 as an AMOC to the inspection, investigative and
corrective actions specified in Table 1, under paragraph 1.E., Compliance, of SB 747-53A2675, dated
October 12, 2006, required by paragraph (f), and to the reporting procedures with the corresponding
compliance times required by paragraph (i), of FAA AD 2006-24-05. When this SB specifies contacting
Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with
paragraph (j) of the FAA AD. All provisions of FAA AD 2006-24-05 that are not specifically referenced
in this paragraph remain fully applicable and must be complied with.
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 1-7, 12-13:
Elapsed HoursTask HoursNumber of PersonsTask
63.255068Inspect for Skin
Cracks - Groups 1-7,
12, 13
46.53728Inspect for Doubler
Disbonds - Groups 1-
7, 12, 13 (a)
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### Page 55

Group 1-7, 12-13:
Elapsed HoursTask HoursNumber of PersonsTask
109.75878TOTAL FOR EACH AIRPLANE
(a) The data given is for an external ultrasonic inspection. The hours for a detailed
inspection will be similar with additional manpower required to get access to
the skin panels from inside the airplane.
Group 8-11, 14:
Elapsed HoursTask HoursNumber of PersonsTask
47.53808Inspect for Skin
Cracks - Groups 8-
11, 14
352808Inspect for Doubler
Disbonds - Groups 8-
11, 14 (a)
82.5660TOTAL FOR EACH AIRPLANE
(a) The data given is for an external ultrasonic inspection. The hours for a detailed
inspection will be similar with additional manpower required to get access to
the skin panels from inside the airplane.
H. Weight and Balance Changes
None.
I. Electrical Load Data
Not changed.
J. References
1. Existing Data
a. Boeing Service Bulletin 747-53-2272, 747-53A2253, 747-53A2303, 747-53A2305,
747-53A2321, 747-53A2396, 747-53A2406, 747-53A2409, 747-53A2499, 747-53A2563,
747-53A2675, 747-53A2367
b. Boeing Service Letter 747-SL-51-048
c. Boeing Service Related Problem (SRP) 747-SRP-53-0297
d. Federal Aviation Administration (FAA) Airworthiness Directive 2006-20-02, 2006-24-02,
2006-24-05
e. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19
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f. 747 Non-Destructive Testing (NDT) Manual Part 4, 53-30-03, Part 6, 51-00-00, Part 6, 53-30-00,
Part 6, 53-30-02, Part 6, 53-30-03, Part 6, 53-30-06, Part 6, 53-30-19, Part 9, 51-00-03, Part
9, 51-00-04
g. 747-100/200/300 Aircraft Maintenance Manual (AMM) 25-21-00, 25-22-00, 25-24-00, 25-25-00,
25-27-00, 25-28-00, 25-52-00, 53-21-02
h. 747-100/200/300 Structural Repair Manual (SRM) 51-10-01, 51-30-05, 53, 53-30-03
i. 747-400 Aircraft Maintenance Manual (AMM) 25-21-00, 25-22-00, 25-24-00, 25-25-00,
25-27-00, 25-28-00, 25-52-00, 53-21-02
j. 747-400 Structural Repair Manual (SRM) 51-10-02, 51-40-05, 53, 53-00-01, 53-10-01
k. 747-400F Structural Repair Manual (SRM) 51-10-02, 51-40-05, 53, 53-00-01, 53-10-01
l. 747-400LCF Structural Repair Manual (SRM) 51-10-02, 53
m. 747-400SF Structural Repair Manual (SRM) 51-10-02, 51-40-05, 53, 53-00-01, 53-10-01
n. 747-SP Structural Repair Manual (SRM) 51-10-01, 51-30-05, 53, 53-39-01
2. Data supplied with this Service Bulletin
None.
3. Installation Drawings Used in the Preparation of this Service Bulletin
TitleDrawing Number
Skin Diagram - Fuselage, Model 74765B00006
The above drawing was used to prepare this service bulletin. The drawing is not necessary to
make the specified changes, and is not supplied with this service bulletin. The drawing 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 and new DTI requirements for the structure
affected are contained in Paragraph 1.E., Compliance of this service bulletin.
L. Interchangeability and Intermixability of Parts
Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.
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2.    MATERIAL INFORMATION
A. Material - Price and Availability
None.
B. Industry Support Information
Boeing warranty remedies are not available for the inspection and/or repair procedures given in 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. Use the approved fastener and process material substitutions in accordance with
SRM Chapter 51.
4. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures,
and SWPM 20-10-19 for the wire separation requirements, as accepted procedures.
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.
8. 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.
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.
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B. WORK INSTRUCTIONS
1. INSPECTION FOR CRACKS AND DISCREPANT FASTENERS:
Do an external surface HFEC inspection for skin cracks and a Detailed inspection for discrepant
countersunk fasteners in accordance with the applicable figures identified in the table below and
in accordance with Paragraph 1.E., Compliance. A fastener is to be found discrepant if the fastener
head is cracked, deformed, or missing as specified in the figure identified below. The compliance
data refers to inspection Zone 1 and Zone 2 which are to be located in accordance with FIGURE
14.
The inspections for skin cracks and discrepant countersunk fasteners is to be repeated in
accordance with Paragraph 1.E., Compliance.
Inspection for skin cracks or discrepant fasteners in accordance with this service bulletin is not
necessary if/where conditions are as follows:
– Inspection for discrepant fasteners in accordance with this service bulletin is not necessary
in areas common to repairs or where a modification doubler or replacement skin panel has
been installed.
– Inspection for skin cracks in accordance with this service bulletin is not necessary in the area
under an internal or external repair doubler if the repair doubler extends three or more fastener
rows beyond the fastener row common to the inspection area. Any post-repair inspections
that apply to the repair area (such as SRM or RAP program inspections) remain applicable
after the inspections and changes given in this service bulletin are accomplished.
NOTE: Inspections for cracks are still necessary in areas where the oversize fastener repair
was installed in accordance with 747-100/200/300 SRM 53-30-03 Figure 57, Detail
III, 747-400 SRM 53-10-01 Repair 4, Detail III, 747-400F SRM 53-10-01 Repair 4,
Detail III, 747-400SF SRM 53-10-01 Repair 4, Detail III, or 747-SP SRM 53-39-01
Figure 48, Detail III. Because these SRM repairs were developed for damage found
with the inspections given in service bulletin 747-53A2409, the instruction for these
repairs may state that repair is not necessary at other areas (areas outside those
inspected per service bulletin 747-53A2409). This service bulletin instructs to inspect
in locations not included in the inspection given in service bulletin 747-53A2409, and
disbonds found with the inspection given in this service bulletin may be eligible for
repair even if the SRM states that a repair is not necessary.
– Inspection is not necessary in the area where an external doubler has been installed with a
015U0451-( ) kit in accordance with Boeing Service Bulletin 747-53A2321 (between body
stations 340 and 520 and stringers S-6 and S-14).
– Inspection is not necessary in the area where a replacement skin panel has been installed in
accordance with Boeing Service Bulletin 747-53A2321 with a 015U0451-( ) kit received from
Boeing on or after September 26, 1996.
– Inspection is not necessary in the area where external modification doublers have been
installed in accordance with Boeing Service Bulletin 747-53A2253 , 747-53-2272, 747-53A2303,
747-53A2305, 747-53A2367 , or 747-53A2499.
– Inspection is not necessary in the area where an external modification doubler has been
installed above main entry door no. 1 in accordance with Boeing Service Bulletin 747-53A2396.
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