June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 79 

### Commercial **Airplane Group**  

# 747 Service Bulletin

**Number: 747-53A2303** Date: June 02, 1988 Revision 2: October 01, 2009 ATA System: 5310 5311
**SUBJECT:** FUSELAGE - Nose Section - Station 400 to 520 Stringer Lap Splice Inspection, Repair and Modification 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1989 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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, 707, 717, 727, 737, 747, 757, 767, 777, BBJ, BOEING BUSINESS JET, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-90, the Boeing logo and the Boeing livery are among the trademarks owned by Boeing or its subsidiaries. No intellectual property license (express or implied) is granted in connection with this document or otherwise.**BLANK PAGE** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

BLANK PAGE**Table of Contents** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**Table of Contents** Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 36 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 36 4. Process Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 36 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 40 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 40 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 FIGURE 1: THIS FIGURE IS DELETED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 FIGURE 2: INITIAL INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 FIGURE 3: INTERNAL ACCESS AND RESTORATION. . . . . . . . . . . . . . . . . . . . . . . . . 54 FIGURE 4: THIS FIGURE IS DELETED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODI FICATION INSPECTION . . . . . . 57 FIGURE 6: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED BY SERVICE BULLETIN 747-53A2321 - INSPECTION . . . . . . . . . . . . . . . . . 64 FIGURE 7: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND SKIN REPLACEMENT MODIFICATION BY SERVICE BULLETIN 747-53A2321 - INSPECTION . . . . . . . . 66 FIGURE 8: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED**Table of Contents** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION . . . . . . . . . 68 FIGURE 9: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND SKIN REPLACEMENT MODIFICATION BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION 70 APPENDIX A: DISCREPANT STRUCTURE REPORT . . . . . . . . . . . . . . . . . . . . . . . . . 72 APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS . . . . . . . . . . . . . . . . . . 75 APPENDIX C: EXTENSION OF THE 141U2100 MODIFICATION DOUBLERS WHEN AN SRM REPAIR IS PRESENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 79 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53A2303** 

### Revision Transmittal Sheet Original Issue: June 02, 1988 Revision 2: October 01, 2009 ATA System: 5310 5311
**SUBJECT:** FUSELAGE - Nose Section - Station 400 to 520 Stringer Lap Splice Inspection, Repair and Modification

This Revision includes all pages of the service bulletin.
**COMPLIANCE INFORMATION RELATED TO THIS REVISION** More work is necessary on airplanes on which the Flight Safety inspections are being accomplished. The repeat inspection interval has been reduced from 5,000 flight-cycles to 3,000 flight-cycles since the last Flight Safety inspection was accomplished, or within 1,000 flight-cycles after the date on Revision 2, whichever occurs later. More work is also necessary on airplanes modified as shown in the initial release and/or Revision 1 of this service bulletin. Airplanes that have accomplished a protruding head fastener modification or a modification as given in certain Structural Repair Manual (SRM) repairs will be required to accomplish the doubler modification as given in Paragraph 1.E., Compliance. In addition, airplanes that have had a structural modification accomplished as given in the SRM or other Boeing service bulletins will be required to accomplish post modification inspections as given in Paragraph 1.E., Compliance.
**REASON FOR REVISION** This revision is sent to update inspection requirements and to update the post modification inspection requirements for airplanes that have accomplished a modification as shown in the initial release and/or Revision 1 of this service bulletin. This revision is also sent to remove the optional top row protruding head fastener modification, as well as modifications per certain SRM repairs. Changes to this service bulletin include: – Airworthiness Directive (AD) 90-21-17 supersedes AD 89-05-03. – Specific repair figures in SRM 53-30-03 are referenced as an acceptable modification. – Compliance information is added to Paragraph 1.E., Compliance. Existing compliance information to accomplish the Flight Safety Inspection Program, the Economics Based Inspection Program and the modification has been moved from the logic diagrams in Figure 1 to Tables 1 and 2 of Paragraph 1.E., Compliance. Compliance information for the repeat post modification inspections is included in Table 3 of Paragraph 1.E., Compliance. New compliance information for the inspection and modification of airplanes with certain SRM repairs or the optional top row protruding head fastener modification that was shown in the original release and Revision 1 of this service bulletin is added to Tables 4 and 5. – The 747 Non-Destructive Test manual, Boeing service bulletins, a Service Related Problem, a Boeing Document, an AD and SRM references are added to Paragraph 1.J., References. – Primer and Sealant are added to the Parts and Materials Supplied by the Operator. – Paragraph 3.B., Work Instructions have been extensively rewritten.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

– Figure 1 is deleted. The information previously in the logic diagrams has been moved to the tables in Paragraph 1.E., Compliance. – The NDT procedures referenced in Figure 2 have been changed. – Figure 4 is deleted to remove the top row protruding head fastener modification. – Figure 5 is added to inspect the top row protruding head fastener modification accomplished by previous releases of this service bulletin for cracks. – Figure 6 is added to provide inspections for airplanes with doublers installed by this service bulletin and doublers installed by service bulletin 747-53A2321 for cracks. – Figure 7 is added to provide inspections for airplanes with doublers installed by this service bulletin and the skin replacement modification by service bulletin 747-53A2321 for cracks. – Figure 8 is added to provide alternative inspections to the Figure 6 inspections for cracks. – Figure 9 is added to provide alternative inspections to the Figure 7 inspections for cracks. – Appendix B is added to provide alternative lap splice trim instructions. – Appendix C is added to show how the Drawing 141U2100 modification doublers should be changed when an SRM repair is present in the modification area. Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. 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** Original Issue: June 02, 1988 Revision 1: March 29, 1990 Revision 2: October 1, 2009Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 79 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53A2303** 

### Summary Original Issue: June 02, 1988 Revision 2: October 01, 2009 ATA System: 5310 5311
**SUBJECT:** FUSELAGE - Nose Section - Station 400 to 520 Stringer Lap Splice Inspection, Repair and Modification

**CONCURRENT REQUIREMENTS**
None.
**BACKGROUND** Based on a structural review of the 747 airplane, incorporation of a modification per Revision 2 of this service bulletin is recommended on aging airplanes. Accomplishment of the intent of this service bulletin will ensure the structural integrity of the fuselage skin lap splice along stringer 6 left and stringer 6 right from Station (STA) 400 to 520 throughout the operational life of the airplane. One operator reported fuselage skin cracks of 0.16 inch long at 10 rivet locations in the upper fastener row of the left stringer 6 skin lap splice between STA 400 and 420 on one airplane. This airplane had accumulated 29,439 flight hours and 22,248 reduced pressure cycles (approximately 19,000 equivalent full pressure cycles). Investigation revealed the cracks were initiated in the fastener countersinks and were propagated by cabin pressurization cyclic loading. A structural reassessment of the 747 airplane was made under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure the safe operation of 747 airplanes throughout their operational life. As a result of this reassessment, the stringer lap splice, left and right sides, between STA 400 and 520 have been determined to be structurally significant and critical to the structural integrity of the airplane. Skin cracks not detected prior to reaching critical crack length may result in in-flight depressurization of the airplane and the inability to withstand current regulatory fail-safe loads. Therefore, a flight safety inspection program is defined in this bulletin which will continue throughout the operational life of the airplane. This service bulletin is the subject of Federal Aviation Administration (FAA) Airworthiness Directives (AD) 90-21-17 and 90-06-06. AD 90-21-17 supersedes AD 89-05-03. Boeing Service Related Problem (SRP) 747OP-SRP-53-0292 is related to this service bulletin.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**ACTION** (PRR 82284R) As recommended by the 747 Aging Fleet Structures Working Group, accomplish a modification per the accomplishment instructions at or before the accumulation of 23,000 flight-cycles. Airplanes on which a protruding head fastener modification or a modification as given in certain SRM repairs are required to accomplish the external doubler modification given in this service bulletin at the time given in Paragraph 1.E., Compliance, Table 5. This bulletin details a flight safety inspection program, an economics based inspection program, structural modifications to improve the resistance to cracking along the affected skin lap splice, and an after-modification inspection program. The flight safety inspection program is defined as follows: On unmodified airplanes initiate a detailed and High Frequency Eddy Current (HFEC) inspection at the time given in Paragraph 1.E., Compliance, Table 1. If a crack is not indicated, reinspect as given in Paragraph 1.E., Compliance, Table 1. As an alternative, install a modification which will consist of the installation of an external doubler. If cracks are indicated during the initial inspection, modify the skin lap splice per the accomplishment instructions of this service bulletin before further flight. On any area left unmodified, repeat the initial inspection as given in Paragraph 1.E., Compliance, Table 1. At modified areas initiate the post modification internal and external inspections at the time given in Paragraph 1.E., Compliance, Table 3. If no cracks are found, repeat these inspections as given in Paragraph 1.E., Compliance, Table 3. If cracks are found, repair per 747 Structural Repair Manual or contact Boeing. If the Service Bulletin 747-53-2272 Zone 2 modification has previously been accomplished, the after modification inspections per this service bulletin may be performed using external methods only, and with a repeat interval as given in Paragraph 1.E., Compliance, Table 3. The Economic Based Inspection Program has a lower initial threshold than the Flight Safety Inspection Program. The repeat inspection interval, inspection methods, and options are the same for both inspection programs.
**EFFECTIVITY** 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR and 747SP series airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.
**COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directives 90-21-17 and 90-06-06 are related to this service bulletin. Refer to Paragraph 1.E., Compliance.
**INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**MANPOWER** Refer to Paragraph 1.G., Manpower.
**MATERIAL INFORMATION** Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

STA 520 STA 400

STA 400 STA 520 UPPER SKIN PANEL INSPECT FOR CRACKS IN TOP ROW

3 ROW SPLICE SHOWN 4 ROW SPLICE SIMILAR STRINGER NO.6

LEFT SIDE SHOWN RIGHT SIDE SIMILAR

LOWER SKIN PANEL AND ACCOMPLISH A STRUCTURAL MODIFICATIONJ76126Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 79 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53A2303** Original Issue: June 02, 1988 Revision 2: October 01, 2009 ATA System: 5310 5311
**SUBJECT:** FUSELAGE - Nose Section - Station 400 to 520 Stringer Lap Splice Inspection, Repair and Modification

**1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 82284R for data about this change.

Airplane models:

**GROUP CONFIGURATION DESCRIPTION** 1 - 747-100, -200B and -200F airplanes, line number 1 through 200 with standard upper deck configuration of one right side crew entry door. 2 - 747-100 and -200B airplanes, line number 1 through 200 with right and left side upper deck crew entry doors. 3 - 747-100, -100B, -200B, -200C, -200F, 747SP and 747SR airplanes, line number 201 through 628 with standard upper deck configuration of one right side crew entry door. 4 - 747-100, -100B, -200B, -200C, -200F, 747SP and 747SR airplanes, line number 201 through 628 with right and left side upper deck crew entry doors. 5 - 747-200 and -300 airplanes, line number 201 through 628 with a 208 inch Stretched Upper Deck (SUD) configuration, including airplanes modified to SUD per Master Change 42360-( )Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

747-100 747-100B 747-200B 747-200C 747-200F 747-300 747SP 747SR IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER AAR AIRCRAFT SALES & LEASING (AFD) 4 RB681–RB682 RB691 AERO CONTROLS (AEO) 2 RA722–RA723 AEROLINEAS ARGENTINAS (ARG) 3 RD122–RD127 AEROSUR (REO) 5 RS235 AFRICA UNITED HOLDING CO. (UHD) 3 RB010 4 RD513 AFX (AXL) 3 RD201 AGES AIRCRAFT SALES & LEASING (AGJ) 1 RB004 AIR ATLANTA ICELANDIC (AID) 3 RD414 RR204 4 RD141–RD142 RD144 RD647–RD648 RD771 5 RS211 RS233 RS237 AIR CANADA (ACN) 4 RA749–RA750 RD531 AIR CHINA (BEJ) 3 RD782 AIR FRANCE (AFA) 3 RR306 4 RD655 RD657–RD658 AIR GULF FALCON (GFG) 1 RA535 RA537 AIR INDIA (AIN) 4 RA729 RA731 AIR UNIVERSAL (UVL) 4 RD649 AMERICAN AIRLINES (AAL) 3 RA266Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

ARKIA ISRAELI AIRLINES (ARK) 1 RA253 3 RR332 ATLAS AIR (TLS) 3 RD361–RD366 RD691–RD692 4 RD641 RD646 RD753–RD754 RJ333 RR301 AVIATION EXPOSURE MANAGEMENT (EXU) 4 RD131–RD132 RD143 BANC OF AMERICA LEASING (SBC) 1 RD001–RD002 BOEING (TBC) 4 RR222–RR223 BOEING AIRCRAFT HOLDING CO. (BHC) 3 RD181 RJ132 4 RB693 RD451–RD454 BOEING WICHITA MOD CENTER (WMC) 4 RD455 C.A.L. CARGO AIR LINES (CRG) 4 RJ331–RJ332 C.I.T. LEASING CORPORATION (TCI) 3 RB011 RD047 CAPITAL ASSET MANAGEMENT (CPG) 3 RD053 CARGAIR (CGL) 3 RD203 CARGO B AIRLINES (CBO) 3 RR561 CATHAY PACIFIC AIRWAYS (CAT) 3 RD581 4 RD358 CORSAIR (COR) 5 RS239–RS240 DUBAI AIR WING (DAW) 3 RD622 EL AL ISRAEL AIRLINES (ELA) 4 RR225–RR226Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

ELITE AIRLINES S.A. (ETE) 4 RB696 EUROPEAN AVIATION AIR CHARTER (EUL) 4 RD135–RD138 EVERGREEN INTERNATIONAL A/L (EVR) 1 RA028 RA631 RA633 3 RB604 RB607 RD004 RD041–RD043 RJ131 RJ133 4 RD772–RD773 EVERGREEN TRADE INC. (EVG) 1 RA371 3 RD056–RD057 RD241 RD243 RD254–RD255 RD257 EXPORT RESTRICTED AIRPLANES (YWV) 1 RA101–RA103 RA112 RA161–RA163 3 RG141–RG142 RG171 4 RB711 RD681–RD682 RG101–RG104 RR001–RR004 FINOVA (GRB) 1 RA651 GA TELESIS, LLC (GTG) 4 RB692 RB697 GE (GEC) 1 RA016 GECAS (GEF) 1 RA007 RA013 RA027 GENERIC CUSTOMER/SUPPLIER (XXX) 3 RR202–RR203 4 RD104 RD592 5 RD382 GLOBAL AIR LEASING (GAO) 3 RG164 GLOBAL PEACE INITIATIVE (GPI) 3 RG174 GRACE CATHEDRAL INC. (GCI) 4 RG193 HORTA (HOB) 3 RG163 INTERNATIONAL AIR LEASES (IAL) 3 RB006Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

IRAQI AIRWAYS (IRQ) 3 RG095 RG172 RJ301–RJ303 JAL INTERNATIONAL (JAL) 5 RS251–RS252 RS254 JET AERO HOLDINGS (JHD) 3 RG122 JOHNSON SPACE CENTER (ZBR) 1 RA908 3 RB601 RG091 JUMBO JET LEASING (JJL) 1 RA526 RA532–RA534 RA539 KABO AIR (KAB) 1 RA560 2 RA305 3 RB008 RD121 4 RA316 KALITTA AIR (KAC) 1 RA401–RA402 RA524 RA635 RA913 3 RA546 RA548 RB605 RD052 RD054 RD083 RD224–RD225 RD571 RD621 RD623 RR262 RR265 RR361–RR362 4 RD221 RR261 RR501 KUWAIT AIRWAYS (KUW) 3 RD202 RD204 L-3 COMMUNICATIONS (LCS) 4 RD352 LOGISTIC AIR, INC. (LGA) 1 RA015 RA217 RA910 4 RB722–RB723 MK AIRLINES (MKA) 3 RD055 RD441 RD781 RR022–RR023 RR264 RR336 4 RR224 RR421 RR504 NEA HOLDINGS, INC. (NEA) 1 RB001 3 RD045–RD046 NIPPON CARGO AIRLINES (NCA) 4 RR552–RR553Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

NORTHWEST AIRLINES (NWA) 3 RD242 RD251–RD253 RD258–RD259 RR341–RR342 RR344–RR345 4 RR005 RR503 OMAN ROYAL FLIGHT (RFO) 3 RG161 ORIENT THAI AIRLINES (OTH) 1 RA540 3 RA528 RA543–RA544 4 RD222 RD516 5 RS253 RS292 RS712 PAKISTAN INT'L AIRLINES (PIA) 4 RD701–RD702 5 RS301 PHUKET AIRLINES (PHK) 4 RD421–RD424 5 RD381 RD605 RS238 RS241 RS711 POLAR AIR CARGO (PAO) 4 RD752 PRATT & WHITNEY ENGINE SERVICE (PWE) 3 RG213 4 RG222 PRONAIR (TXI) 4 RR221 QANTAS (QAN) 5 RS273 ROYAL AIR MAROC (RAM) 3 RD671 SATAIR (SAI) 5 RD606 SAUDI ARABIAN AIRLINES (SVA) 3 RB741–RB746 RB748 RH121 5 RS311–RS315 SAUDI ROYAL FLIGHT (SRF) 3 RH101 RH122 5 RS699 SKYLEASE I DBA TRADEWINDS AIRLINES (TWN) 3 RD461 4 RA726Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

SOUTH AFRICAN AIRWAYS (SAA) 5 RS212 RS232 RS236 SOUTHERN AIR (SOF) 3 RD411–RD412 RD583 RR302–RR305 4 RB695 RD272 RD642–RD643 RD751 RR551 5 RD383 RD601–RD602 RD607 RS721 STAR AIRLINES (SRQ) 4 RD426 SUO1 (UO1) 3 RB013–RB016 TESIS AVIATION ENTERPRISE (TEV) 3 RA784 TRANSAERO AIRLINES (TRX) 3 RD226 RD471–RD475 4 RD356 5 RS271 TRANSATLANTIC INTL AIRLINES (TIB) 3 RG173 UPS (UPS) 1 RA026 RA029 RA033 RA902 RA912 RA915–RA916 3 RD051 RD058–RD059 4 RD593 VIRGIN ATLANTIC AIRWAYS (VAA) 4 RD357 WHIRLPOOL FINANCIAL CORP. (ZZW) 1 RB005 WINGS WORLD WIDE (WWW) 4 RG221 WORLDWIDE AIRCRAFT HOLDING CO. (WAH) 3 RG008 YEMENIA (YEM) 3 RG162 YONA (IOP) 3 RG009 4 RG191Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

IDENTIFICATION BY VARIABLE NUMBER **Variable Group** RA001–RA007 1 RA009 1 RA011–RA020 1 RA022–RA034 1 RA101–RA110 1 RA112–RA115 1 RA161–RA164 1 RA201 1 RA203 1 RA216–RA217 1 RA245 2 RA251–RA259 1 RA261–RA266 3 RA301–RA308 2 RA309 1 RA310 2 RA311 1 RA312 2 RA313–RA318 4 RA351–RA360 1 RA369–RA373 1 RA401–RA414 1 RA415–RA418 3 RA501–RA502 1 RA521–RA527 1 RA528 3 RA532–RA535 1 RA537–RA540 1 RA541–RA548 3 RA551–RA552 1 RA559–RA561 1 RA581–RA582 1 RA585 1 RA601–RA602 1 RA631–RA635 1 RA651–RA652 1 RA671–RA675 2Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

RA677 2 RA701–RA702 1 RA722–RA724 2 RA725–RA726 4 RA728–RA731 4 RA741–RA743 2 RA744–RA745 4 RA749–RA750 4 RA761–RA762 1 RA781–RA782 1 RA783–RA784 3 RA901–RA916 1 RB001–RB005 1 RB006–RB016 3 RB041–RB044 1 RB071–RB075 1 RB101–RB102 1 RB601–RB602 3 RB604–RB607 3 RB681–RB697 4 RB711 4 RB721–RB723 4 RB741–RB748 3 RD001–RD002 1 RD003–RD004 3 RD021–RD022 3 RD041–RD059 3 RD071–RD072 3 RD081–RD083 3 RD091 3 RD101–RD102 3 RD103–RD104 4 RD121–RD127 3 RD131–RD144 4 RD171–RD172 3 RD181–RD183 3 RD201–RD204 3 RD221–RD222 4 RD223–RD226 3 **Variable Group**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

RD241–RD243 3 RD251–RD259 3 RD271–RD272 4 RD351–RD358 4 RD361–RD366 3 RD381–RD383 5 RD411–RD414 3 RD421–RD426 4 RD431–RD435 3 RD441–RD442 3 RD451–RD456 4 RD461 3 RD471–RD475 3 RD513–RD519 4 RD531–RD533 4 RD551 3 RD561 4 RD571 3 RD581–RD583 3 RD592–RD593 4 RD601–RD607 5 RD621–RD623 3 RD641–RD649 4 RD651–RD655 4 RD657–RD658 4 RD661 4 RD671 3 RD681–RD682 4 RD691–RD692 3 RD701–RD702 4 RD721–RD722 5 RD741–RD742 3 RD751–RD754 4 RD761 4 RD771–RD773 4 RD781–RD782 3 RE001 4 RG001–RG009 3 RG091 3 **Variable Group**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

RG095 3 RG101–RG104 4 RG121–RG126 3 RG141–RG142 3 RG161–RG164 3 RG171–RG174 3 RG191–RG193 4 RG211–RG213 3 RG221–RG222 4 RH101 3 RH111–RH112 4 RH121–RH122 3 RJ131–RJ133 3 RJ151–RJ152 3 RJ301–RJ303 3 RJ331–RJ333 4 RR001–RR005 4 RR021–RR023 3 RR031 3 RR201 1 RR202–RR204 3 RR221–RR226 4 RR261 4 RR262–RR265 3 RR301 4 RR302–RR306 3 RR331–RR332 3 RR336 3 RR341–RR345 3 RR361–RR362 3 RR421–RR422 4 RR501 4 RR503–RR504 4 RR521 3 RR531 3 RR551–RR553 4 RR561 3 RS211–RS212 5 RS221–RS222 5 **Variable Group**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

2. Spares Affected
None. **B. Concurrent Requirements**
None.
**C. Reason** As a result of the Federal Aviation Administration (FAA) Sponsored Aging Fleet Conference, a 747 Structures Working Group with Airline and Boeing members and FAA observers was formed to review structural service bulletin modifications and recommend selected service bulletins for incorporation on aging airplanes. These service bulletin modifications have been recommended for incorporation on aging 747 airplanes. Accomplishment of the inspection programs and modifications described in this service bulletin will ensure the structural integrity of the fuselage skin lap splice along the left and right stringer 6 from Station (STA) 400 to 520 throughout the operational life of the airplane. One operator reported fuselage skin cracks of 0.16 inch long at 10 rivet locations in the upper fastener row of the left stringer 6 skin lap splice between STA 400 and 420 on one airplane. This airplane had accumulated 29,439 flight hours and 22,248 reduce pressure cycles (approximately 19,000 equivalent full pressure cycles). Investigation revealed the cracks were initiated in the fastener countersinks and were propagated by cabin pressurization cyclic loading. A structural reassessment of the 747 airplane was made under the requirements of FAA Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 25.571 as amended in 1978, to ensure the safe operation of 747 airplanes throughout their operational life. As a result of this reassessment, the stringer lap splice, left and right sides, between STA 400 and 520 have been determined to be structurally significant and critical to the structural integrity of the airplane. Skin cracks not detected prior to reaching critical crack length many result in in-flight depressurization of the airplane and the inability to withstand current regulatory fail-safe loads. RS231–RS241 5 RS251–RS254 5 RS271–RS273 5 RS291–RS292 5 RS301 5 RS311–RS315 5 RS699 5 RS701–RS702 5 RS711–RS712 5 RS721 5 **Variable Group**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

The modifications contained in this service bulletin do not alter the skin lap splices structural environment such that a flight safety inspection is no longer required. Therefore, a flight safety inspection program is defined in this bulletin which will continue throughout the operational life of the airplane. This service bulletin is the subject of Federal Aviation Administration (FAA) Airworthiness Directive (AD) 90-21-17. AD 90-21-17 supersedes AD 89-05-03. Boeing Service Related Problem (SRP) 747OP-SRP-53-0292 is related to this service bulletin. Revision 1 is issued to recommend modification per this service bulletin for incorporation on aging 747 airplanes. The incorporation threshold for this service bulletin is shown in the Description and Accomplishment Instructions. In addition, this revision is also issued to formalize and update Telex Alert Service Bulletin 747-53A2303, to add an economics based initial inspection program, provides complete details on the external doubler modification, and adds reference to Federal Aviation Administration Airworthiness Directive AD-89-05-03, Amendment 39-6146. Revision 2 is sent to update inspection requirements and to update the post modification inspection requirements for airplanes that have accomplished a modification as shown in the initial release and/ or Revision 1 of this service bulletin. This revision is also sent to remove the optional top row protruding head fastener modification, as well as modifications per certain SRM repairs. Changes to this service bulletin include: – Airworthiness Directive (AD) 90-21-17 supersedes AD 89-05-03. – Specific repair figures in SRM 53-30-03 are referenced as an acceptable modification. – Compliance information is added to Paragraph 1.E., Compliance. Existing compliance information to accomplish the Flight Safety Inspection Program, the Economics Based Inspection Program and the modification has been moved from the logic diagrams in Figure 1 to Tables 1 and 2 of Paragraph 1.E., Compliance. Compliance information for the repeat post modification inspections is included in Table 3 of Paragraph 1.E., Compliance. New compliance information for the inspection and modification of airplanes with certain SRM repairs or the optional top row protruding head fastener modification that was shown in the original release and Revision 1 of this service bulletin is added to Tables 4 and 5. – The 747 Non-Destructive Test manual, Boeing service bulletins, a Service Related Problem, a Boeing Document, an AD and SRM references are added to Paragraph 1.J., References. – Primer and Sealant are added to the Parts and Materials Supplied by the Operator. – Paragraph 3.B., Work Instructions have been extensively rewritten. – Figure 1 is deleted. The information previously in the logic diagrams has been moved to the tables in Paragraph 1.E., Compliance. – The NDT procedures referenced in Figure 2 have been changed. – Figure 4 is deleted to remove the top row protruding head fastener modification. – Figure 5 is added to inspect the top row protruding head fastener modification accomplished by previous releases of this service bulletin for cracks. – Figure 6 is added to provide inspections for airplanes with doublers installed by this service bulletin and doublers installed by service bulletin 747-53A2321 for cracks. – Figure 7 is added to provide inspections for airplanes with doublers installed by this service bulletin and the skin replacement modification by service bulletin 747-53A2321 for cracks. – Figure 8 is added to provide alternative inspections to the Figure 6 inspections for cracks. – Figure 9 is added to provide alternative inspections to the Figure 7 inspections for cracks. – Appendix B is added to provide alternative lap splice trim instructions. – Appendix C is added to show how the Drawing 141U2100 modification doublers should be changed when an SRM repair is present in the modification area.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**D. Description** As recommended by the 747 Aging Fleet Structures Working Group, accomplish a modification per the accomplishment instructions at or before the accumulation of 23,000 flight-cycles. Airplanes on which a protruding head fastener modification or a modification as given in certain SRM repairs are required to accomplish the external doubler modification given in this service bulletin at the time given in Paragraph 1.E., Compliance, Table 5. This service bulletin defines a flight safety inspection program and an economics based inspection program to detect cracking of the skin lap splice along the left and right stringer 6 between STA 400to 520. Modifications are also described that will improve the resistance to this cracking. An aftermodification inspection program is also defined. The flight safety and economics based inspection programs differ in inspection thresholds and basic intent. The modifications described herein are alternatives to the repeated initial flight safety or economics based inspections, but incorporation does not eliminate the need for the flight safety after modification inspections.
**NOTE:** 1. Concurrent incorporation of Boeing service bulletin 747-53-2272 "FUSELAGE - Nose Section 41 Body Frame Structure Replacement and Reinforcement" Zone 2 modification and Boeing service bulletin 747-53-2253, "FUSELAGE - Nose Section - Station 340 to 400 Stinger 6 Inspection and Modification", is recommended because of similar access and inspection requirements. 2. For Group 1 and Group 2 airplanes to be modified per this service bulletin revision 1 or later should, concurrent with any of the modification described herein delaminate stringer 6 skin lap splice, remove adhesive and replace with fay surface sealant in accordance with 747 Structural Repair Manual Subject 53-30-03 Figure 10. Group 2 airplanes are not required to delaminate the left stringer 6 skin lap splice where the skin lap splice contains four rows of fasteners. 3. Initial inspection thresholds shall be determined from the total number of pressurized flights that obtain a 2.0 psi pressure differential or greater. 4. On group 5 airplanes which have been modified to the Stretched Upper Deck (SUD), 280 inch extension per MC 42360-( ), the above initial inspection thresholds are measured from the time of the SUD modification, when the body skin panel in this area were replaced. 5. Airplanes that have previously been modified per Structural Repair Manual 53-30-03 Figure 10 along the left and right stringer from STA 400 to 520 prior to the initial release of this service bulletin, without accomplishing the initial flight safety inspection program of this bulletin, are to be inspected at the thresholds specified in the flight safety inspection program, but a different inspection procedure is defined herein. 6. On Group 1 and 2 airplanes, the instructions for the structural modification will be based on the condition of the individual airplane modified. Operators will need to make a contract with Boeing to get instructions as given in Paragraph 1.E., Compliance. Flight Safety Inspection Program:Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

The flight safety inspection program is the minimum inspection program necessary to ensure the structural integrity of the affected skin lap splice throughout the operation life of the airplane. The intent of this inspection program is to detect cracks between STA 400 to 520 on the left and right stringer 6 of the fuselage skin lap splice prior to their reaching critical crack length. Since the program is concerned only with safety, without economic consideration any cracking found may be extensive and potentially costly to repair. For airplanes on which the full modification per this bulletin has not been previously accomplished, initiate a detailed and eddy current inspection at the time given in Paragraph 1.E., Compliance, Table 1. If no cracks are indicated, reinspect at the time given in Paragraph 1.E., Compliance. As an alternative, install the external doubler modification over the skin lap splice as given in this service bulletin. At all unmodified areas of the skin lap splice, repeat the initial inspections at the time given in Paragraph 1.E., Compliance, Table 1. For any lap splice which requires repair per the 747 SRM for cracking per this bulletin Revision 2 or later, the lap splice should have incorporated the modification specified per this service bulletin at the time given in Paragraph 1.E., Compliance. After modification, internal and external eddy current inspections are required on modified areas of the skin lap splice at the times given in Paragraph 1.E., Compliance, Table 3. As an alternative, the post modification inspections required per this service bulletin may be performed using external methods only, but with a reduced repeat interval as given in Paragraph 1.E., Compliance, Table 3. The flight safety addendum is a summary of the required inspection. Refer to Appendix A. Economics Based Inspection Program - Operator’s Option: The economics based inspection program applies only to those affected airplanes on which a modification has not been accomplished. On these airplanes, at the operator’s option, this inspection program may be implemented in lieu of the initial flight safety inspection until a modification is accomplished. After modification inspections are in accordance with the "Flight Safety Inspection Program". The intent of this optional program is to give guidance to enable the operator to initiate inspection and modification prior to extensive skin lap splice cracking which may result in more costly repairs. For applicable airplanes, initiate detailed and eddy current inspections as given in Paragraph 1.E., Compliance, Table 1. The repeat inspection interval, inspection methods, and options are the same for both inspection programs.
Modification: As recommended by the 747 Aging Fleet Structures Working Group, modification should be accomplished at or before the accumulation of 23,000 flight-cycles. The modification consists of installing the specified external doubler modification to the skin lap splice. This modification improves the fuselage skin lap splice resistance to cracking between STA 400 to 520 along the left and right stringer 6. However, this modification does not alter the skin lap splice’sstructural environment such that a flight safety inspection is no longer required. Start to do the postmodification inspections at the time given in Paragraph 1.E., Compliance, Table 3.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

This service bulletin is the subject of Federal Aviation Administration (FAA) Airworthiness Directives (AD) 90-21-17 and 90-06-06. This service bulletin is listed in Boeing Document D6-35999.
PLEASE REPORT YOUR PLANNED ACTION AND INSPECTION RESULTS TO BOEING CUSTOMER SUPPORT AS SOON AS EACH INSPECTION IS COMPLETE.
THESE REPORTS WILL ASSIST BOEING IN COMPILING DATA RELATIVE TO FLEET SERVICE EXPERIENCE AND PROVIDE FOR THE MOST COST EFFECTIVE MEANS OF RESOLVING THE REPORTED PROBLEM.
**NOTE:** Contact Boeing for instructions if any damaged areas exceed the specified limits. To expedite Boeing response, be specific when defining and locating damage. Circumstances leading to the damage and any secondary effects, when known, should be included in the communication and followed by sketches and photographs when appropriate. In addition, where corrosion is involved, length, width, and greatest depth of clean-up are required.
CONTACT: BOEING COMMERCIAL AIRPLANES ATTENTION: MANAGER, AIRLINE SUPPORT Revision 2 - More work is necessary on airplanes on which the Flight Safety inspections are being accomplished. The repeat inspection interval has been reduced from 5,000 flight-cycles to 3,000 flight-cycles since the last Flight Safety inspection was accomplished, or within 1,000 flight-cycles after the date on Revision 2, whichever occurs later. More work is also necessary on airplanes modified as shown in the initial release and/or Revision 1 of this service bulletin. Airplanes that have accomplished a protruding head fastener modification or a modification as given in certain Structural Repair Manual (SRM) repairs will be required to accomplish the doubler modification as given in Paragraph 1.E., Compliance. In addition, airplanes that have had a structural modification accomplished as given in the SRM or other Boeing service bulletins will be required to accomplish post modification inspections as given in Paragraph 1.E., Compliance. **E. Compliance** The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration (FAA) Airworthiness Directives 90-21-17 and 90-06-06 are related to this service bulletin.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

Boeing recommends operators do the inspections and modifications shown in this service bulletin at the following intervals: Table 1: Flight Safety and Economics Based Inspection Programs

**Condition Action Compliance Time (Whichever**  **Occurs Later) Repeat Interval**  **(Not to Exceed)** Airplanes with 16,000 total flight-cycles or more as of March 31, 1989 that have not had the modification shown in any version of this service bulletin done. (a) (d) (e) (f) (g) (i) Inspect the skin lap splice between STA 400 and 520 for cracks at unmodified areas as given in Paragraph 3.B., PART 1. Within 100 flight-cycles after March 31, 1989, unless previously accomplished within the last 4,900 flight-cycles before March 31, 1989. (i) -

Airplanes with between 12,000 and 16,000 total flight-cycles as of March 31, 1989, that have not had the modification shown in any version of this service bulletin done. (a) (d) (e) (f) (g) (i) Inspect the skin lap splice between STA 400 and 520 for cracks at unmodified areas as given in Paragraph 3.B., PART 1. Before 16,100 total flight-cycles or within 1,000 flight-cycles after March 31, 1989, whichever occurs first, unless previously accomplished within the last 4,000 flight-cycles before March 31, 1989. (a) (i) -

Airplanes with 12,000 total flight-cycles or less as of March 31, 1989 that have not had the modification shown in any version of this service bulletin done. (a) (d) (e) (f) (g) (i) Inspect the skin lap splice between STA 400 and 520 for cracks at unmodified areas as given in Paragraph 3.B., PART 1. Before 13,000 total flight-cycles, unless previously accomplished within the last 5,000 flight-cycles before March 31, 1989. (a) (d) (i) -

Airplanes that have had the modification shown in the initial release or Revision 1 or Revision 2 of this service bulletin done. Refer to Table 3: Post Modifications Inspections. Refer to Table 3: Post Modifications Inspections Refer to Table 3: Post Modifications Inspections
Crack(s) found. Install a repair as given in Paragraph 3.B., PART 2. (b) (e) Before further flight. (h)

As an alternative, do the modification as given in Paragraph 3.B., PART 3. (b) (c) No crack(s) found. (j) Repeat inspections as given in Paragraph 3.B., PART 1. Within 3,000 flight-cycles after the last inspection. Within 1,000 flight-cycles after the date on Revision 2 of this service bulletin. 3,000 flightcycles (b)
As an alternative, do the modification as given in Paragraph 3.B., PART 3. (b) (c) (a) On Group 5 airplanes that have been modified by Boeing to the Stretched Upper Deck (SUD) configuration, the initial inspection thresholds should be calculated from the time that the SUD modification was accomplished, when the skin panel in this area was replaced.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

(b) Accomplishment of the modification given in Table 2 terminates the requirement for repeat inspections given in this table. (c) After accomplishment of the modification, do the post modification inspections as given in Table 3.(d) For the economics based inspection program, start to do the inspections at or before 8,000 total flightcycles. (e) Local repairs accomplished on the lap splice must be removed and the structural modification as given in Paragraph 3.B., PART 3 must be installed before the accumulation of 23,000 total flight-cycles or within 30 months after repair installation, whichever occurs earlier. Refer to Table 2. (f) For airplanes that have had the Service Bulletin 747-53A2321 modification installed, refer to Table 3 for post-modification inspections.
**NOTE:** FAA AD 2006-24-02 mandates the Service Bulletin 747-53A2321 modification for airplanes line number 1 through 200 at 20,000 total flight-cycles. The Service Bulletin 747-53A2321 modification was optional for all other affected airplanes. (g) For Groups 1 and 2 airplanes (line number 1 - 200) that have had the skin lap joint cold bond delamination repair given in 747-100/200/300 SRM 53-30-03 Figure 10 accomplished, and have also had 1/ 16 inch diameter oversize protruding head fasteners installed in the upper row, treat this configuration as a modification and refer to Table 3 for Post-modification inspections. (h) After accomplishment of the repair, until the structural modification given in Paragraph 3.B, PART 3 is done, any additional requirements given in the applicable SRM must be followed, including repeat inspections of blind fasteners. (i) March 31, 1989 is the effective date of FAA AD 89-05-03, which was superseded by FAA AD 90-21-17. (j) This applies to unmodified sections of the lap splice outside the repair area.
Table 2: Modification **Condition Action Compliance Time** All airplanes where no previous modifications or repairs have been installed in the affected area. Accomplish the structural modification as given in Paragraph 3.b., PART 3. (a) Before 23,000 total flight-cycles or within 4 years after April 17, 1990 (the effective date of FAA AD 90-06-06), whichever occurs later. Airplanes that have not had the structural modification accomplished, but that have had lap joint repairs accomplished. Remove any existing repairs and accomplish the structural modification as given in Paragraph 3.b., PART 3. (a) (b) Before 23,000 total flight-cycles or within 30 months after repair installation, whichever occurs earlier. (a) After accomplishment of the modification, do the post modification inspections as given in Table 3. (b) Until the structural modification given in Paragraph 3.B, PART 3 is accomplished, any additional requirements as given in the SRM must be followed, including repeat inspections for blind fastener repairs. Table 1: Flight Safety and Economics Based Inspection Programs

**Condition Action Compliance Time (Whichever**  **Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

Table 3: Post Modification Inspections

**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** Airplanes modified with the Service Bulletin 747- 53A2321 repair doubler installation and the Drawing 141U2100 doubler installation. (b) (c) Accomplish an internal and external HFEC inspection for cracks as given in Paragraph 3.B., PART 4. (a) Within 10,000 flight-cycles after the modification was installed. (f) Within 1,000 flight cycles after the date on Revision 2 of this service bulletin or 5,000 flight cycles after the last detailed and High Frequency Eddy Current inspection of the skin lap splice as given in a previous version of this service bulletin, whichever occurs first. -

Airplanes that have had the structural modification as given in Drawing 141U2100 accomplished. (b) (c) (e) Accomplish an internal and external HFEC inspection for cracks as given in Paragraph 3.B., PART 4. (a) Within 10,000 flight-cycles after the modification was installed. Within 1,000 flight cycles after the date on Revision 2 of this service bulletin or 5,000 flight cycles after the last detailed and High Frequency Eddy Current inspection of the skin lap splice as given in a previous version of this service bulletin, whichever occurs first. -

Airplanes that have had a structural modification as given in 747 SRM 53-30-03 Figure 19, 25, 28, or 34 accomplished for the full length of the lap joint. (b) (d) Accomplish an internal and external HFEC inspection for cracks as given in Paragraph 3.B., PART 4. (a) Within 10,000 flight-cycles after the modification was installed. Within 1,000 flight cycles after the date on Revision 2 of this service bulletin or 5,000 flight cycles after the last detailed and High Frequency Eddy Current inspection of the skin lap splice as given in a previous version of this service bulletin, whichever occurs first. -

Airplanes that have had a protruding head fastener modification or any SRM modification other than 747-100/ 200/300 SRM 53-30-03 Figure 19, 25, 28, or 34 for the full length of the lap splice. (c) Refer to Table 4 and Table 5 for inspections and modification. Refer to Table 4 and Table 5 for inspections and modification. Refer to Table 4 and Table 5 for inspections and modification.

No crack(s) found. Repeat inspection as given in Paragraph 3.B., PART 4. (a) Within 3,000 flight-cycles afterthe last postmodification inspection. Within 1,000 flight-cycles after the date on Revision 2 of this service bulletin. 3,000 flightcycles (a)

Crack(s) found Contact Boeing for repair instructions and do the repair. Repair before further flight. -Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

(a) As an alternative, do inspections for cracks as shown in Figure 8 or Figure 9. The repeat inspection interval is 800 flight-cycles. (b) If the lower skin panel was replaced as given in Boeing Service Bulletin 747-53A2321, but the external doubler was not installed, this inspection is not applicable. Contact Boeing for inspection instructions or do inspections in accordance with Table 1. (c) On Group 1 and 2 airplanes, more work may be required on airplanes that were delivered with cold bonded lap splices. Contact Boeing for further information and/or instructions regarding this issue as given in Table 5. Boeing Service Bulletins 747-53A2463, 747-53-2253, 747-53A2267, and 747-53-2307 are also related to this issue. (d) In areas of the crew entry door, the 747 SRM repair/modification should not extend forward of STA 425. If it extends forward of STA 425, contact Boeing for inspection instructions. (e) Includes doubler configurations modified as given in Appendix C. (f) Compliance time since installation of the Drawing 141U2100 modification. Table 4: Inspections of Certain Configurations

**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)** In areas where a 747 SRM external doubler repair was installed as a modification, except as given in 747 SRM 53-30-03 Figure 19, 25, 28, or 34 for the full length of the lap joint. (a) Accomplish an internal HFEC inspection for cracks as given in Paragraph 3.B., PART 5. Within 10,000 flight-cycles after the structural modification was installed. Within 500 flightcycles after the date on Revision 2 of this service bulletin. -

In areas where a protruding head fastener modification was installed as given in the initial release or Revision 1 of this service bulletin. Accomplish an external HFEC inspection for cracks as given in Paragraph 3.B., PART 5. Within 10,000 flight-cycles after the structural modification was installed. Within 500 flightcycles after the date on Revision 2 of this service bulletin. -

Crack(s) found Install a repair as given in Paragraph 3.B., PART 2. (b) (d) Before further flight. (c)

As an alternative, accomplish the modification as given in Paragraph 3.B., PART 3. (b) Affected areas where no crack(s) were found. Repeat inspection as given in Paragraph 3.B., PART 5. Within 500 flight-cycles after the last inspection. 500 flight-cycles (b)
(a) In areas of the crew entry door, the 747 SRM repair/modification should not extend forward of STA 425. If it extends forward of STA 425, contact Boeing for inspection instructions. Table 3: Post Modification Inspections

**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 31 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/ JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. (b) Accomplishment of the modification given in Table 5 is required and terminates the requirement for repeat inspections given in this table. (c) After accomplishment of the repair, until the structural modification given in Paragraph 3.B, PART 3 is done, any additional requirements given in the applicable SRM must be followed, including repeat inspections of blind fasteners. (d) Local repairs accomplished on the lap splice must be removed and the structural modification must be installed within 30 months of the repair as given in Paragraph 3.B., Part 3. Table 5: Modification of Certain Configurations

**Condition Action Compliance Time**  **(Whichever Occurs Later)** Airplanes that have accomplished a protruding head fastener modification and/or a SRM 53-30- 03 repair or modification that is not per Figure 19, 25, 28, or 34 for the full length of the lap splice. (b) Accomplish the Structural Modification as given in Paragraph 3.B., PART 3. Within 14,000 flightcycles after the first modification was installed. (a) Within 3,000 flightcycles after the date on Revision 2 of this service bulletin. (a)

(a) After the modification doubler installation, refer to Table 3 for Post Modification inspections. The post modification inspection thresholds are measured from the time of the modification doubler installation. (b) On Group 1 and 2 airplanes, the instructions for the structural modification will be based on the condition of the lap splices on the individual airplane to be modified. Operators will need to make a contract with Boeing to get instructions for the structural modification. It is suggested that operators contact Boeing with requests for structural modification data at least one year before the data will be needed to make the modification. The airplane is not to be operated without this modification after the compliance time given in this table. Table 4: Inspections of Certain Configurations

**Condition Action Compliance Time**  **(Whichever Occurs Later) Repeat Interval**  **(Not to Exceed)**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 32 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of the applicable inspection andrepair procedures of this service bulletin and the structural modification (and associated postmodification inspection) procedures specified in paragraph 1.E., Compliance of this service bulletin as an AMOC to the corresponding requirements of paragraphs A., B., C., D., and E. of AD 90-21-17. This AMOC only applies to the areas inspected as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph G. of the AD. All provisions of AD 90-21-17 that are not specifically referenced in this paragraph remain fully applicable and must be complied with. The Manager of the FAA Seattle ACO also approves the accomplishment of the structural modification procedures specified in Tables 2 and 5 of paragraph 1.E., Compliance of this service bulletin as an AMOC to the corresponding requirements of paragraph (A) of AD 90-06-06. This AMOC only applies to the areas modified as given in this service bulletin. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph C. of the AD. All provisions of AD 90-06-06 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 service bulletin for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to inspect the work — Time to cure the materials — Time to make the parts — Time to find the tools. **TABLE 1: Initial Inspection (Modification No t Accomplished) (Paragraph 3.B., PART 1)** 

**Task Number of Persons Task Hours Elapsed Hours**  **Left Right Left Right Left Right** Initial Flight Safety Inspection All Groups 1 1 2 2 2 2 Economics Based Inspection. All Groups 1 1 1 1 1 1
**TABLE 2: Structural Modification (Paragraph 3.B., PART 3)**

**Task Number of Persons Task Hours Elapsed Hours**  **Left Right Left Right Left Right** Access All Groups 2 2 10 14 5 7 Open Hole Inspection All Groups 113333 Fastener Modification Group 1 Airplanes 2 2 12 10 6 5Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 33 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

Group 2 Airplanes 2 2 10 10 5 5 Group 3 Airplanes 2 2 12 10 6 5 Group 4 Airplanes 2 2 10 10 5 5 Group 5 Airplanes 2 2 12 12 6 5 External Doubler Modification Group 1 Airplanes 2 2 330 330 165 165 Group 2 Airplanes 2 2 310 330 155 165 Group 3 Airplanes 2 2 340 310 170 155 Group 4 Airplanes 2 2 310 310 155 155 Group 5 Airplanes 2 2 340 340 170 170 SRM Modification All Groups (a) (a) (a) Restoration All Groups 2 2 10 14 5 7 TOTAL FOR EACH AIRPLANE (b) (b) (a) Crew size, Man Hours, Elapsed Time is dependant on the extent of the cracking. Estimates must be made by the operator on a case by case bases. (a) Total Man Hours and Elapsed Time is the sum of the Access, Open Hole Inspection, Restoration and the individual modification to be accomplished.
**TABLE 3: Post Modification Inspections (Paragraph 3.B., PART 4) and Inspection of Certain Configurations (Paragraph 3.B., PART 5.)** 

**Task Number of Persons Task Hours Elapsed Hours**  **Left Right Left Right Left Right** Top Row Protruding Head Fastener Modification Inspection (a) 2 2 16 16 8 8

Doubler Inspection (a) 2 2 31 31 15.5 15.5 Doubler and Skin Modification Inspection (a) 2 2 31 31 15.5 15.5

Doubler Alternative Inspection (a) 2 2 38 38 19 19

Doubler and Skin Modification Alternative Inspection (a) 2 2 30.5 30.5 15.25 15.25 **TABLE 2: Structural Modification (Paragraph 3.B., PART 3)**

**Task Number of Persons Task Hours Elapsed Hours**  **Left Right Left Right Left Right**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** Additional time will be required for repairs if cracks are found. **H. Weight and Balance Changes**

**I. Electrical Load Data** Not applicable.
**J. References** 1. Existing Data: a. Engineering Change Memo PRR 82284R SRM Modification Inspection (a) (b) (b) (b)
(a) Operators will not be required to accomplish all of the post modification inspections. The required inspection will be determined on the airplanes configuration at the stringer 6 skin lap splice, left and right sides. (b) Crew size, Man Hours, Elapsed Time is dependant on the extent of the repair. Estimates must be made by the operator on a case by case bases.

**Applicability Change in Weight (Pounds)**  **Change in Moment (Pound-Inches)**  **Left Side Right Side Left Side Right Side**  Protruding Head Fastener Modification (c) All Groups +0.1 +0.1 +50 +50 External Doubler Modification Group 1 Airplanes +19 +19 +8740 +8740 Group 2 Airplanes +20 +19 +10120 +8740 Group 3 Airplanes +22 +20 +10120 +9660 Group 4 Airplanes +20 +21 +10120 +9660 Group 5 Airplanes +23 +23 +10580 +10580 Structural Repair Manual Modification All Groups (a) (a) Total (b) (b) (a) Changes in weight and moment is not given due to the variability of the Structural Repair Manual modifications (b) Total weight and moment change is the sum of the weights or the sum of the moments for the modifications made to an individual airplane’s left and right side. (c) The protruding head fastener modification is deleted in Revision 2. **TABLE 3: Post Modification Inspections (Paragraph 3.B., PART 4) and Inspection of Certain Configurations (Paragraph 3.B., PART 5.)** 

**Task Number of Persons Task Hours Elapsed Hours**  **Left Right Left Right Left Right**Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

b. Engineering Change Memo MC 42360-( ) c. Service Related Problem (SRP) 747OP-SRP-53-0292 d. 747 Maintenance Manual (AMM) Subject 25-21-04, 25-22-03, 25-23-01, 25-24-00, 25-24-11, 25-24-12, 25-24-19, 25-25-01, 25-25-04, 25-26-02, 25-26-03, 25-26-06, 25-28-15, 25-28-23, 25-40-03, 52-51-01, 52-51-00, 52-13-01. e. 747 Structural Repair Manual (SRM) Subject 51-10-02. f. 747 Structural Repair Manual (SRM) Subject 53-30-03 g. 747 Nondestructive Test (NDT) Manual, Part 6, Subject 51-00-00, 53-30-00, 53-30-03, 53-30-05, 53-30-10, 53-30-15, 53-30-19 h. Boeing Service Bulletin 747-53-2253 "FUSELAGE - Nose Section - Station 340 to 400 Stinger 6 Inspection and Modification" i. Boeing Service Bulletin 747-53-2272 "FUSELAGE - Nose Section 41 Body Frame Structure Replacement and Reinforcement" j. Boeing Service Bulletin 747-53A2321, "FUSELAGE - Skin - Upper Body Skin Inspection and Repair at Longitudinal Rows of Fasteners at Stringers Along Flat Side in Section 41" k. Boeing Service Letter 747-SL-53-44, dated 31 May, 1988
l. FAA Airworthiness Directive 89-05-03, 90-21-17, 90-06-06 m. Boeing Document D6-35999, "Aging Airplane Service Bulletin Structural Modification Program, Model 747" n. Boeing Document D6-36181, "Repair Assessment Guidelines - Model 747" o. Supplement Structural Inspection Document (SSID) D6-35022 Item F-25 p. Boeing Parts Standards Document D-590 q. Boeing Drawing 012W6100Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

2. Data supplied with this Service Bulletin: a. Drawings:

3. Installation Drawings Used in the Preparation of this Service Bulletin:
None.
4. Process Data: Boeing Process specifications referred to on the drawings are not given in this service bulletin since these procedures are frequently used as standard shop practices.
**K. Publications Affected**
1. Publications

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** Refer to Paragraph 2.C., Parts Necessary For Each Airplane, for interchangeability and intermixability information. **Drawing Number Title Sheet DCN ADCN** 141U2100 Doubler Installation - Exterior Stringer 6 Station 400 to 520, Repair PL (a) - - 1 (a) - - 2 (a) - - 3 (a) - - 4 (a) - - 5 (a) - - (a) Transmitted with Revision 1.

**Publication Chapter-Section** 747 Structural Repair Manual 53-30Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary For Each Airplane as shown below. If there is a limit to the quantity (QTY) of available kits, a supply sequence is given by Spares. More kits become available as shown in the Reorder Lead Time (ROLT). ROLT is calculated from the date Boeing gets the purchase order.

The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. After the Unit Price date, new price and ROLT data is applicable. Prices are in United States dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of the methods that follow: 1. Order on-line via ATA Spec 2000 or Boeing Part Page 2. Fax to (206) 662-7145 3. Spares Customer Support - MC 36-65 Boeing Spares Department P.O. Box 3707 Seattle, Washington 98124-2207 USA **B. Industry Support Information** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. **Kit Number Name Date QTY ROLT**  **(Weeks) Unit Price thru**  **Mar 29/90** 141U2100-1 Doubler Kit 06/22/90 4 22 $319.00 141U2100-3 Doubler Kit 06/22/90 4 22 $515.00 141U2100-4 Doubler Kit 06/22/90 3 22 $515.00 141U2100-5 Doubler Kit 06/22/90 3 22 $325.00 141U2100-6 Doubler Kit 06/22/90 4 22 $325.00 141U2100-7 Doubler Kit 06/22/90 3 22 $318.00 141U2100-8 Doubler Kit 06/22/90 4 22 $516.00Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**C. Parts Necessary For Each Airplane**
1. Kits/Parts: To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability.
**NOTE:** One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane.
**Kit 141U2100 New Part**  **Number QTY**  **Name Notes -8 -7 -6 -5 -4 -3 -1**  141U2100-1 . . . . . . - External Doubler, Group 3, Left Side 141U2100-3 . . . . . - . External Doubler, Gr oups 2 and 4, Left Side 141U2100-4 . . . . - . . External Doubler, Gr oups 3 and 4, Right Side 141U2100-5 . . . - . . . External Doubler, Group 5, Left Side 141U2100-6 . . - . . . . External Doubler, Group 5, Right Side 141U2100-7 . - . . . . . External Doubler, Group 1, Left Side 141U2100-8 - . . . . . . External Doubler, Group 5, Right Side 141U2100-11 . 1 . . . . 1 Doubler 141U2100-13 . 1 . . . . 1 Doubler 141U2100-15 . . . . . 1 . Doubler 141U2100-16 1 . . . 1 . . Doubler 141U2100-17 . . . . . 1 . Doubler 141U2100-18 1 . . . 1 . . Doubler 141U2100-19 . . . . 1 . Doubler 141U2100-20 . . . . 1 . . Doubler 141U2100-22 1 . . . . . . Doubler 141U2100-23 . . . 1 . . . Doubler 141U2100-24 . . 1 . . . . Doubler 141U2100-25 . . . 1 . . . Doubler 141U2100-26 . . 1 . . . . Doubler BACR15CE5D5 614 764 664 664 557 557 705 Rivet BACR15CE5D6 6 10 10 10 6 6 10 Rivet BACR15CE5D7 27 . . 27 27 . Rivet BACR15CE6D8 2 . . . 2 2 4 Rivet BACR15CE6D10 3 . . . 5 5 . RivetOriginal Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

BACR15DS7D6 . 2 2 2 . . 2 Rivet BACR15DS7D7 8 14 16 16 8 8 16 Rivet BACR15DS7D8 22 28 28 28 22 22 31 Rivet BACR15DS7D9 29 35 30 30 29 29 31 Rivet BACR15DS7D10 7 . . . 7 7 . Rivet BACR15BB5D5 59 115 117 117 59 59 117 Rivet BACR15BB5D6 98 . . . 65 65 . Rivet BACR15BB5D7 3 . . . 3 3 . Rivet BACR15BB6D7 185 257 257 257 185 185 257 Rivet BACR15BB6D8 25 14 14 14 25 25 10 Rivet BACR15BB6D9 12 . . . 12 12 . Rivet BACR15BB6D10 2 . . . . . . Rivet BACR15BB8D7 94 188 39 39 . . . Rivet BACR15BB8D8 99 151 23 23 47 47 23 Rivet BACR15BB8D9 66 28 25 25 66 66 25 Rivet BACR15BB8D10 35 . 14 14 35 35 . Rivet BACR15BB8D11 9 . . . 6 6 . Rivet BACR15ET7D7 6 8 288 288 149 149 288 Rivet BACR15ET7D8 10 23 148 148 83 83 148 Rivet BACR15ET7D9 18 6 9 9 28 28 4 Rivet BACR15ET7D10 53 . . . 58 58 . Rivet BACR15ET7D11 26 . . . 26 26 . Rivet BACR15MY6K5Y 3 . . . 3 3 . Rivet BACR15MY6K7Y 39 . . . 39 39 . Rivet BACR15MY6K8Y 5 . . . 2 2 . Rivet BACR15MY6K9Y . . . . 3 3 . Rivet BACR15NW6K6Y 2 . . . 2 2 . Rivet BACC30R6 49 . . . 49 49 . Collar **Kit 141U2100 New Part**  **Number QTY**  **Name Notes -8 -7 -6 -5 -4 -3 -1** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

2. Parts and Materials Supplied by the Operator:

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. **Part Number / Specification QTY Name Notes**  BMS 5-95 32 oz. Sealant (a) BMS 10-11, Type I 8 oz. Primer (a) - As Required Modification Parts (b) (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to 747-100/200/300 SRM 53-30-03 Figures 19, 25, 28 or 34 for the materials required to accomplish the lap joint modification.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**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. Unless shown differently, these dimensions and tolerances are used: — Linear dimensions are in inches — Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch — Angular tolerance is plus or minus 2 degrees — Hole dimensions for standard solid rivets are given in 747 Structural Repair Manual, Chapter 51 — Torque limits to tighten nuts and bolts are given in 747 Structural Repair Manual, Chapter 51. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. As recommended by the 747 Aging Fleet Structures Working Group, accomplish themodification per this service bulletin prior to, or upon the accumulation of 23,000 flightcycles 5. Adequate lighting must be used for this inspection. The eddy current inspections may beconducted without removal of the paint, provided the paint does not interfere (see NonDestructive Test (NDT) Manual D6-7170) with the inspections. Paint must be removed using an approved chemical stripper in any situation where the inspector determines that the paint is interfering with proper functioning of the inspection equipment or where the fastener heads are not clearly visible. 6. Inspection is not required at Station (STA) 400 to 416 at those locations where there is an upper deck door cutout. Right side on all Group 1, 2, 3 and 4 airplanes. Left side on all Group 2 and 4 airplanes. 7. Refer to Paragraph 1.E., Compliance for thresholds and repeat inspection intervals. 8. For approved fastener and process material substitutions, refer to 747 SRM, Chapter 51, Alternate fasteners are given in 747 SRM Chapter 51 and Boeing Drawing 012W6100. 9. If the length of any fastener specified in this service bulletin does not meet the 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.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

10. 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. 11. These work instructions refer to procedures included on 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 "as given in" are included in the instruction, the procedure in the Boeing document must be used. 12. Refer to Appendix A for the Flight Safety Addendum for this service bulletin. 13. Refer to Appendix B for alternate skin trim instructions. 14. Refer to Appendix C for instructions to extend the 141U2100 modification doublers if previous SRM repairs are present.
**B. WORK INSTRUCTIONS**
**PART 1 - FLIGHT SAFETY INSPECTION PROGRAM** 1. Initial inspection on airplanes on which the modification given in PART 3 or in any previous version of this service bulletin has not been accomplished: a. At the time specified in Paragraph 1.E., Compliance, inspect the skin lap splice at Stringer 6, from STA 400 to STA 520, on the left and right side of the airplane, for cracks as given in Figure 2.
**NOTE:** The optional Economics Based Inspection Program may be initiated at an earlier time than the Flight Safety Inspection Program, as given in Paragraph 1.E., Compliance. Other than the initial inspection threshold, all other compliance requirements for the Economics Based Inspection Program are the same as the Flight Safety Inspection Program. b. If no cracks are found, repeat the inspections given in Figure 2 at the times specified in Paragraph 1.E., Compliance. As an alternative, accomplish the modification in PART 3 to terminate the Flight Safety or Economics Based inspection program. c. If a crack is found, accomplish the modification in PART 3. As a time-limited alternative, accomplish a repair as given in PART 2. Continue to do inspections in unrepaired areas as given in Figure 2. Continue to do inspections in repaired areas as given in Paragraph 1.E., Compliance, Table 1 and the related footnotes. Send Boeing a report of any discrepancies that are found.
**PART 2 - REPAIR** 1. Gain access as necessary for removal of the top row of fasteners along the left and right stringer 6 lap splice as given in Figure 3.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** 1. This repair may be installed temporarily instead of the modification in PART 3, but it does not terminate the inspections that are necessary as given in PART 1. 2. In all locations where cracks are trimmed, use care to make sure that adjacent internal tear straps, door cutout internal bear straps, and other internal structure are not cut or otherwise damaged. 3. For any skin lap splice repair installed as given in previous revisions of this service bulletin, the lap splice must incorporate the modification specified in PART 3 of Revision 2 at the time specified in Paragraph 1.E., Compliance, Table 2 or Table 4.
4. If skin cracks are found in the area of the 0.025 inch thick bonded internal doubler at STA 425 to STA 457, adjacent to the upper deck door cutout, the repair should be based on the total thickness of the cracked or trimmed out skin and doubler. The skin trim out should not extend forward of STA 425 for this condition. 5. If cracks extend forward of STA 425 at the door cutout, contact Boeing for repair instructions. 2. Repair cracks as given in 747-100/200/300 SRM 53-30-03 Figures 17, 20, 23, 26, 29, or 32. Contact Boeing if the inner skin panel is to be trimmed. 3. Install equipment that was removed for access as given in Figure 3. 4. Put the airplane back to a serviceable condition. Continue to do inspections in unrepaired areas as given in Paragraph 1.E., Compliance. Do the modification given in PART 3 at the time given in Paragraph 1.E., Compliance.
**PART 3 - MODIFICATION** 1. Gain access as necessary for removal of the fasteners along the left and right stringer 6 lap splice as given in Figure 3.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** 1. These modification options may be used as an alternative to the inspections given in PART 1. 2. It is recommended that the scribe line inspections given in Boeing Service Bulletin 747-53A2563, "Fuselage - Skin - Inspections of the Fuselage Skin and Butt Joint Splice Straps for Scribe Lines" be done in the affected area prior to doubler installation. If the scribe line inspections are not done prior to doubler installation, it may be necessary to remove the doublers to accomplish the scribe line inspections. 3. On Group 1 and 2 airplanes to be modified as given in Revision 1 of this service bulletin or later, at the same time as the modification given in this service bulletin is installed, delaminate the stringer 6 lap splice, remove the adhesive, and replace with faying surface sealant as given in 747-100/200/300 SRM 53-30-03 Figure 10. On Group 2 airplanes it is not necessary to delaminate the left side stringer 6 lap splice where the splice contains four rows of fasteners. 4. In all locations where cracks are trimmed, use care to make sure that adjacent internal tear straps, door cutout internal bear straps, and other internal structure are not cut or otherwise damaged.
5. If skin cracks are found in the area of the 0.025 inch thick bonded internal doubler at STA 425 to STA 457, adjacent to the upper deck door cutout, the modification should be based on the total thickness of the cracked or trimmed out skin and doubler. The skin trim out should not extend forward of STA 425 for this condition. 6. If cracks extend forward of STA 425 at the door cutout, contact Boeing for repair instructions. 7. The protruding head fastener modification has been removed from this service bulletin as part of Revision 2. 2. If cracks were not found during the PART 1 or PART 5 inspections, do the steps that follow: a. Remove any SRM repair that exists between STA 400 and STA 520 in the area of the modification. Contact Boeing if the inner skin was trimmed, since the modification per Drawing 141U2100 may not be applicable. b. Remove the lap joint fasteners and do open hole HFEC inspections at the top and bottom rows of lap joint fastener holes as given in 747 NDT, Part 6, 51-00-00 Figure 1, 11, or 16. c. If cracks are found, go to Step 3. d. If no cracks are found, do the external doubler modification as given in Drawing 141U2100 Sheets 1 - 5.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** 1. Protruding head fasteners may be oversized up to 0.250 inch in diameter common to the existing lap joint and frame flanges. 1.7D edge margin must be maintained in the frame flanges and 4D spacing must be maintained in the skin. If fastener holes common to the upper row of the existing lap joint exceed these limitations, refer to Appendix B for alternate trim instructions. 2. In the area of removed SRM doublers or trim outs, locally extend the profile of the lower doubler to act as a filler for the upper skin trim. Additionally, extend the Drawing 141U2100 doublers above and below the removed SRM repair such that the perimeter row of fasteners is installed in new fastener holes. Refer to Appendix C for additional instructions. Install BACR15BB5D( ) rivets in the new fastener holes. e. Finish the modification area as necessary to match adjacent structure. 3. If cracks were found during the PART 1 or PART 5 inspections, or during the open-hole HFEC inspection done prior to the modification, do the steps that follow: a. Remove any SRM repair that exists between STA 400 and STA 520 in the area of the modification. Contact Boeing if the inner skin was trimmed, other than as given in Appendix B, since the modification per Drawing 141U2100 may not be applicable. b. Trim out all cracks as given in 747-100/200/300 SRM 53-30-03 Figures 17, 20, 23, 26, 29, or 32, or as given in Appendix B. Contact Boeing for instructions if cracks were found in the inner skin at the bottom row of fastener holes in the lap joint. c. Do the external doubler modification as given in Drawing 141U2100 Sheets 1 - 5.
**NOTE:** 1. Protruding head fasteners may be oversized up to 0.250 inch in diameter common to the existing lap joint and frame flanges. 1.7D edge margin must be maintained in the frame flanges and 4D spacing must be maintained in the skin. If fastener holes common to the upper row of the existing lap joint exceed these limitations, refer to Appendix B for alternate trim instructions. 2. In the area of removed SRM doublers or trim outs, locally extend the profile of the lower doubler to act as a filler for the upper skin trim. Additionally, extend the Drawing 141U2100 doublers above and below the removed SRM repair such that the perimeter row of fasteners is installed in new fastener holes. Refer to Appendix C for additional instructions. Install BACR15BB5D( ) rivets in the new fastener holes. d. Finish the modification area as necessary to match adjacent structure. 4. Install equipment that was removed for access as given in Figure 3. 5. Put the airplane back to a serviceable condition. Do post-modification inspections as given in PART 4 at the times given in Paragraph 1.E., Compliance, Table 3.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**PART 4 - POST-MODIFICATION INSPECTIONS** 1. At the times given in Paragraph 1.E., Compliance, Table 3:
**NOTE:** For all Group 1 and 2 airplanes that have been modified as given in this revision or previous revisions of this service bulletin, contact Boeing for additional instructions as given in Paragraph 1.E., Compliance, Table 5. More work may be necessary on airplanes that were delivered with cold bonded lap splices. a. If the doubler installation as given in Service Bulletin 747-53A2321 has been installed and a doubler has also been installed as given in this service bulletin, do a detailed inspection and internal and external HFEC inspections of the skin in the area of the modification as given in Figure 6.
**NOTE:** As an alternative for airplanes on which the Service Bulletin 747-53-2272 Zone 2 modification has been previously accomplished, it is acceptable to do only external inspections as given in Figure 8. However, the alternative inspection given in Figure 8 has a shorter repeat inspection interval, as given in Paragraph 1.E., Compliance, Table 3. b. If the modification given on Drawing 141U2100 (including doubler configurations modified as given in Appendix C), or as given in 747-100/200/300 SRM 53-30-03 Figure 19, 25, 28, or 34 has been accomplished for the full length of the lap joint, do a detailed inspection and internal and external HFEC inspections of the skin in the area of the modification as given in Figure 7.
**NOTE:** As an alternative for airplanes on which the Service Bulletin 747-53-2272 Zone 2 modification has been previously accomplished, it is acceptable to do only external inspections as given in Figure 9. However, the alternative inspection given in Figure 9 has a shorter repeat inspection interval, as given in Paragraph 1.E., Compliance, Table 4. 2. If no cracks are found, do the inspections again at the time specified in Paragraph 1.E., Compliance, Table 3. 3. If cracks are found, repair before further flight. Contact Boeing for repair instructions. 4. Report any discrepancies using the reporting system described in the Flight Safety Addendum given in Appendix A of this service bulletin. 5. Put the airplane back to a serviceable condition.
**PART 5 - INSPECTION AND MODIFI CATION OF CERTAIN CONFIGURATIONS**  1. At the times given in Paragraph 1.E., Compliance, Table 4: a. In areas where the top row protruding head fastener modification has been accomplished as given in the original release or Revision 1 of this service bulletin, do an external HFEC inspection of the skin around the fasteners in the upper row of the lap joint for cracks as given in Figure 5.Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

b. If a modification as given in 747-100/200/300 SRM 53-30-03 has been accomplished as given in the original release or Revision 1 of this service bulletin, do an internal HFEC inspection for cracks as given in the applicable SRM figures, except at compliance times and intervals given in Paragraph 1.E., Compliance, Table 4. 2. If cracks are found, do one of the following: a. Install a modification as given in PART 3. or b. Install a repair as given in PART 2.
**NOTE:** The full external doubler modification given in PART 3 must be installed at the time specified in Paragraph 1.E., Compliance, Table 5. 3. If no cracks are found, do one of the following: a. Install a modification as given in PART 3. or b. Repeat the inspections as given in Paragraph 1.E., Compliance, Table 4.
**NOTE:** The full external doubler modification given in PART 3 must be installed at the time specified in Paragraph 1.E., Compliance, Table 5.**FIGURE 1: THIS FIGURE IS DELETED**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 48 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 1: THIS FIGURE IS DELETED**

THIS FIGURE IS DELETED.D38438

**(SHEET 1 OF 1) FIGURE 2: INITIAL INSPECTIONS**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 2: INITIAL INSPECTIONS**

STA 520 STA 400 STRINGER NO.6

4 ROW SPLICE LEFT SIDE GROUPS 3 AND 5; RIGHT SIDE GROUP 5 (OPPOSITE) A SEE SEE B 3 ROW SPLICE LEFT SIDE GROUP 1 LOWER SKIN PANEL UPPER SKIN PANEL STA 520 STA 400J76130

**(SHEET 1 OF 5) FIGURE 2: INITIAL INSPECTIONS**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 50 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

A

B 1

1 UPPER SKIN PANEL UPPER SKIN PANEL

LOWER SKIN PANEL LOWER SKIN PANEL

STRINGER 6 STRINGER 6

STA 400 STA 400

FWD UP

FWD UP (4-ROW SPLICE) LEFT SIDE GROUPS 3 AND 5 RIGHT SIDE GROUP 5 (OPPOSITE)

(3-ROW SPLICE) LEFT SIDE GROUP 1 INDICATES AREA TO BE INSPECTEDJ76135

**(SHEET 2 OF 5) FIGURE 2: INITIAL INSPECTIONS**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

STA 520 STA 400 STRINGER NO.6

STA 520 STA 400

UPPER SKIN PANEL DOOR CUTOUT

LOWER SKIN PANEL

C SEE RIGHT SIDE SHOWN

4-ROW SPLICE RIGHT SIDE GROUPS 3 AND 4; LEFT SIDE GROUPS 2 AND 4 (OPPOSITE) SEE D 3-ROW SPLICE RIGHT SIDE GROUPS 1 AND 2J76147

**(SHEET 3 OF 5) FIGURE 2: INITIAL INSPECTIONS**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. UP

FWD UP

FWD STA 417

STA 417 DOOR CUTOUT

DOOR CUTOUT

STRINGER 6 STRINGER 6 UPPER SKIN PANEL

UPPER SKIN PANEL

LOWER SKIN PANEL LOWER SKIN PANEL

INDICATES AREA TO BE INSPECTED 

### D C

1 1

(4-ROW SPLICE) RIGHT SIDE OF GROUPS 3 AND 4 LEFT SIDE GROUPS 2 AND 4 OPPOSITE

(3-ROW SPLICE) RIGHT SIDE OF GROUPS 1 AND 2J76479

**(SHEET 4 OF 5) FIGURE 2: INITIAL INSPECTIONS**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** If protruding head fasteners are in the top row of the lap splice, contact Boeing for inspection instructions. 1. Using a high frequency eddy current method per 747 NDT, 53-30-02 or 747 NDT, 53-30-06 externally inspect the skin at the top row of lap splice between body stations 400 and 520. Also perform a detailed inspection of the skin lap splice for cracking concurrent with the eddy current inspection.

**(SHEET 5 OF 5) FIGURE 3: INTERNAL ACCESS AND RESTORATION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 54 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 3: INTERNAL ACCESS AND RESTORATION**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each airplane. FLIGHT COMPARTMENT AFT PARTITION FLIGHT COMPARTMENT DOOR
E11 RACK ENCLOSURE PARTITION
RIGHT CREW DOOR

LEFT CREW DOOR FORWARD LEFT PARTITION

LOWER CLOSURE PANEL

PSU PANEL STOWAGE BIN UPPER CLOSURE PANEL CENTER LIGHTED REVEAL 1

TYPICAL UPPER DECK CONFIGURATION

WITH LEFT AND RIGHT CREW DOOR (OTHER UPPER DECK CONFIGURATIONS SIMILAR) 2J76482

**(SHEET 1 OF 2) FIGURE 3: INTERNAL ACCESS AND RESTORATION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

1. Remove and salvage equipment and furnishings as required to gain access to Body Station 400 to 520 frames. See the following maintenance manual subjects for removal procedures:

2. Install all items which are removed in the preceding step per the applicable maintenance manual subject or operators comparable procedure. **Equipment Maintenance Manual Subject** Insulation 747-100/200/300 AMM 25-21-04 Ceiling Panels 747-100/200/300 AMM 25-22-03 Passenger Service Units 747-100/200/300 AMM 25-23-01 Forward Closets 747-100/200/300 AMM 25-24-00 Forward Right Partition 747-100/200/300 AMM 25-24-11 Forward Left Partition 747-100/200/300 AMM 25-24-12 Crew Rest Area 747-100/200/300 AMM 25-24-19 Passenger Seats 747-100/200/300 AMM 25-25-01 Wall Mounted Attendant Seat 747-100/200/300 AMM 25-25-04 Stairway Forward Right partition 747-100/200/300 AMM 25-26-02 Stairway Aft Right partition 747-100/200/300 AMM 25-26-03 Stairway Forward Left partition 747-100/200/300 AMM 25-26-06 Sidewall Stowage Units 747-100/200/300 AMM 25-28-15 Overhead Stowage Units 747-100/200/300 AMM 25-28-23 Lavatories 747-100/200/300 AMM 25-40-03 Flight Compartment Door 747-100/200/300 AMM 52-51-01/52-51-00 Crew Entry Door 747-100/200/300 AMM 52-13-01 Insulation 747-100/200/300 AMM 25-21-04 Ceiling Panels 747-100/200/300 AMM 25-22-03 Passenger Service Units 747-100/200/300 AMM 25-23-01 Forward Closets 747-100/200/300 AMM 25-24-00 Forward Right Partition 747-100/200/300 AMM 25-24-11 Forward Left Partition 747-100/200/300 AMM 25-24-12 Crew Rest Area 747-100/200/300 AMM 25-24-19 Passenger Seats 747-100/200/300 AMM 25-25-01 Wall Mounted Attendant Seat 747-100/200/300 AMM 25-25-04 Stairway Forward Right partition 747-100/200/300 AMM 25-26-02 Stairway Aft Right partition 747-100/200/300 AMM 25-26-03 Stairway Forward Left partition 747-100/200/300 AMM 25-26-06 Sidewall Stowage Units 747-100/200/300 AMM 25-28-15 Overhead Stowage Units 747-100/200/300 AMM 25-28-23 Lavatories 747-100/200/300 AMM 25-40-03 Flight Compartment Door 747-100/200/300 AMM 52-51-01/52-51-00 Crew Entry Door 747-100/200/300 AMM 52-13-01

**(SHEET 2 OF 2) FIGURE 4: THIS**  **FIGURE IS DELETED** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 4: THIS FIGURE IS DELETED**

THIS FIGURE IS DELETED.D38438

**(SHEET 1 OF 1) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 5: TOP ROW PROTRUDING HE AD FASTENER MODIFICATION INSPECTION** 

S-6 400 STA

LEFT SIDE SHOWN

400 STA

(3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES STRINGER 6 PANEL LOWER SKIN UPPER SKIN PANEL 520 STA

FWD UP 1

INDICATES AREA TO BE INSPECTEDJ81666

**(SHEET 1 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

UPPER SKIN PANEL STA 400

LOWER SKIN PANEL

STRINGER 6 S-6 LEFT SIDE SHOWN STA 400 STA 520

(4 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES 1

FWD UP

INDICATES AREA TO BE INSPECTEDJ82065

**(SHEET 2 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

LEFT SIDE SHOWN S-6 STA 400 STA 520

(3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 2, GROUP 4 AND GROUP 5 AIRPLANES FWD UP STA 417

DOOR CUTOUT STRINGER 6 UPPER SKIN PANEL

LOWER SKIN PANEL

INDICATES AREA TO BE INSPECTED 1J82031

**(SHEET 3 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 60 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

LEFT SIDE SHOWN S-6 STA 400 STA 520

FWD UP STA 417 UPPER SKIN PANEL

INDICATES AREA TO BE INSPECTED 1

(4-ROW SPLICE) LEFT SIDE OF GROUP 2, GROUP 4 AND GROUP 5 AIRPLANES DOOR CUTOUT

STRINGER 6 LOWER SKIN PANELJ82051

**(SHEET 4 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 61 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

RIGHT SIDE SHOWN S-6 STA 400 STA 520

STA 417

DOOR CUTOUT STRINGER 6 UPPER SKIN PANEL

LOWER SKIN PANEL

INDICATES AREA TO BE INSPECTED 1

(3-ROW SPLICE) RIGHT SIDE OF ALL GROUP AIRPLANES UP

FWDJ81673

**(SHEET 5 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 62 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

RIGHT SIDE SHOWN S-6 STA 400 STA 520

STA 417 UPPER SKIN PANEL

INDICATES AREA TO BE INSPECTED 1

(4-ROW SPLICE)

RIGHT SIDE OF ALL GROUP AIRPLANES DOOR CUTOUT

STRINGER 6 LOWER SKIN PANEL UP

FWDJ81684

**(SHEET 6 OF 7) FIGURE 5: TOP ROW PROTRUDING HEAD FASTENER MODIFICATION INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 63 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

The step number shown below agrees with the number shown in the circle symbols in the figure. 1. Do a High Frequency Eddy Current (HFEC) Inspection, as given in 747 NDT, Part 6, 53-30-19, on the upper skin 360 degrees around the fastener heads, along the top row of fasteners at the stringer 6 lap splice from outside the airplane, left and right sides, for cracks.

**(SHEET 7 OF 7) FIGURE 6: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - INSPECTION** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 64 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 6: DOUBLER INSTALLED BY THIS SE RVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - INSPECTION**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. STA 400

(3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES (RIGHT SIDE AND OTHER GROUPS SIMILAR) STRINGER 6

PANEL LOWER SKIN UPPER SKIN PANEL

LOWER DOUBLER UPPER DOUBLER

INDICATES AREA TO BE INSPECTED STA 520 STA 400 STRINGER NO.6

LEFT SIDE SHOWN (RIGHT SIDE SIMILAR)

FWD UP 1

2 4 3J83748

**(SHEET 1 OF 2) FIGURE 6: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - INSPECTION** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 65 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** The three-row lap splice configuration is shown. The four-row lap splice configuration is similar. 1. Do a High Frequency Eddy Current (HFEC) Inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the skin 360 degrees around the fastener tails, along the top row of fasteners, from inside the airplane, left and right sides, for cracks. Inspections are not necessary at tear strap locations. 2. Do a HFEC Inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the doubler (or tripler which is not shown in the drawings) 360 degrees around the fastener head, along the indicated row of fasteners from outside the airplane, left and right sides, for cracks. In areas common to the tripler installed between STA 421 - 461 (near the upper deck door cutout), inspect the tripler instead of the doubler. 3. Do a detailed inspection of the modification area for cracks from inside the airplane, left and right sides. 4. Do a detailed inspection of the modification area for cracks from outside the airplane, left and right sides.

**(SHEET 2 OF 2) FIGURE 7: DOUBLER INSTALLED BY THIS**  **SERVICE BULLETIN AND SKIN REPLACEMENT MODIFI CATION BY SERVICE BULLETIN 747-53A2321 - INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 66 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 7: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND SKIN REPLACEMENT MODIFICATION BY SERVICE BULLETIN 747-53A2321 - INSPECTION** 

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. STA 400

(3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES (RIGHT SIDE AND OTHER GROUPS SIMILAR) STRINGER 6

PANEL LOWER SKIN UPPER SKIN PANEL

LOWER DOUBLER UPPER DOUBLER

INDICATES AREA TO BE INSPECTED STA 520 STA 400 STRINGER NO.6

LEFT SIDE SHOWN (RIGHT SIDE SIMILAR)

FWD UP 1

2 4 3

1J83750

**(SHEET 1 OF 2) FIGURE 7: DOUBLER INSTALLED BY THIS SE**  **RVICE BULLETIN AND SKIN REPLACEMENT MODIFI CATION BY SERVICE BULLETIN 747-53A2321 - INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 67 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** The three-row lap splice configuration is shown. The four-row lap splice configuration is similar. 1. Do a High Frequency Eddy Current (HFEC) inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the doubler, 360 degrees around the fastener tails, along the top row of fasteners from inside the airplane, left and right sides, for cracks. Inspections are not necessary at tear strap locations. 2. Do a HFEC inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the doubler (or tripler which is not shown in the drawings), 360 degrees around the fastener heads, along the indicated row of fasteners from outside the airplane, left and right sides, for cracks. In areas common to the tripler installed between STA 421 - 461 (near the upper deck door cutout), inspect the tripler instead of the doubler. 3. Do a detailed inspection of the modification area for cracks from inside the airplane, left and right sides. 4. Do a detailed inspection of the modification area for cracks from outside the airplane, left and right sides.

**(SHEET 2 OF 2) FIGURE 8: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 68 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 8: DOUBLER INSTALLED BY THIS SE RVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. (3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES (RIGHT SIDE AND OTHER GROUPS SIMILAR) STA 400

STRINGER 6

PANEL LOWER SKIN UPPER SKIN PANEL

LOWER DOUBLER UPPER DOUBLER

INDICATES AREA TO BE INSPECTED STA 520 STA 400 STRINGER NO.6

LEFT SIDE SHOWN (RIGHT SIDE SIMILAR)

FWD UP 1

2 3J83749

**(SHEET 1 OF 2) FIGURE 8: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND REPAIR DOUBLER INSTALLED**  **BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION** June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 69 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** 1. The alternative inspection shown in this figure is no longer a satisfactory alternative for the Figure 6 inspections if cracks and/or damage is found from previous inspection as shown in this figure. 2. The three-row lap splice configuration is shown. The four-row lap splice configuration is similar. 1. Do a Low Frequency Eddy Current Inspection as given in 747 Non Destructive Test manual, Part 6, Subject 53-30-10 of the skin under the doubler, 360 degrees around the heads of the horizontal top and bottom rows of fasteners for cracks from outside the airplane, left and right sides. 2. Do a High Frequency Eddy Current Inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the doubler, 360 degrees around the heads of the horizontal row of indicated fasteners for cracks from outside the airplane, left and right sides. In areas common to the tripler installed between STA 421 - 461 (near the upper deck door cutout), inspect the tripler instead of the doubler. 3. Do a detailed inspection of the modification area for cracks from outside the airplane, left and right sides.

**(SHEET 2 OF 2) FIGURE 9: DOUBLER INSTALLED BY THIS**  **SERVICE BULLETIN AND SKIN REPLACEMENT MODIFI CATION BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 70 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**FIGURE 9: DOUBLER INSTALLED BY THIS SERVICE BULLETIN AND SKIN REPLACEMENT MODIFICATION BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION** 

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. (3 ROW SPLICE) LEFT SIDE OF GROUP 1, GROUP 3 AND GROUP 5 AIRPLANES (RIGHT SIDE AND OTHER GROUPS SIMILAR) STA 400

STRINGER 6

PANEL LOWER SKIN UPPER SKIN PANEL

LOWER DOUBLER UPPER DOUBLER

INDICATES AREA TO BE INSPECTED STA 520 STA 400 STRINGER NO.6

LEFT SIDE SHOWN (RIGHT SIDE SIMILAR)

FWD UP 1

2 3

1J83751

**(SHEET 1 OF 2) FIGURE 9: DOUBLER INSTALLED BY THIS SE**  **RVICE BULLETIN AND SKIN REPLACEMENT MODIFI CATION BY SERVICE BULLETIN 747-53A2321 - ALTERNATIVE INSPECTION**  June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 71 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** 1. The alternative inspection shown in this figure is no longer a satisfactory alternative for the Figure 7 inspections if cracks and/or damage is found from previous inspection as shown in this figure. 2. The three-row lap splice configuration is shown. The four-row lap splice configuration is similar. 1. Do a Low Frequency Eddy Current Inspection as given in 747 Non Destructive Test manual, Part 6, Subject 53-30-10 of the skin under the doubler, 360 degrees around the heads of the horizontal top row of fasteners for cracks from outside the airplane, left and right sides. 2. Do a High Frequency Eddy Current Inspection as given in 747 NDT, Part 6, 51-00-00 Figure 4 or 747 NDT, Part 6, 53-30-19 of the doubler, 360 degrees around the heads of the horizontal row of indicated fasteners for cracks from outside the airplane, left and right sides. In areas common to the tripler installed between STA 421 - 461 (near the upper deck door cutout), inspect the tripler instead of the doubler. 3. Do a detailed inspection of the Modification Area for cracks from outside the airplane, left and right sides.

**(SHEET 2 OF 2) APPENDIX A: DISCREPANT STRUCTURE REPORT**  Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 72 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**APPENDIX A: DISCREPANT STRUCTURE REPORT**
ADDENDUM
FLIGHT SAFETY SECTION
INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME A structural reassessment of the 747 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56, in accordance with Federal Aviation Regulation (FAR) 2.571, as amended in 1978, to ensure the safe operation of 747 airplanes throughout their operational life. The inspections specified in the tables in Paragraph 1.E., Compliance are recommended for the detection of cracks in the Body Station 400 to 520 skin lap splice at Stringer (S)-6L and S-6R prior to their reaching critical lengths. Failure to detect cracks prior to their reaching critical length may result in in-flight depressurization of the airplane and the inability to withstand current regulatory failsafe loads. Any skin splice cracks should be repaired prior to further flight unless specifically approved by your cognizant regulatory agency. Report any discrepancies to Boeing Customer Support Engineering using the reporting system described in this addendum. Boeing requests that operators use the following Structural Significant Item (SSI) reporting system to report any discrepancies that are found in accomplishing a Flight Safety Inspection. 1. Upon recognition of a discrepancy, the following information should be sent to Boeing: Heading: ATTENTION - SSI DISCREPANCY - SERVICE BULLETIN RELATED – Service bulletin number – Airplane serial number on which discrepancy was found – Identification of structural item found damaged – Flight cycles and hours on damaged item – Location and description of damage including direction and size – When discovered and inspection method used Send a message through your Boeing Field Service Representative or directly to: 747 Customer Support Engineering 2. An operator’s follow up report containing all available pertinent data, relative to the structural discrepancy, shall be sent to Boeing within 10 working days. A summary of the information that should be reported is sown in the DISCRAPANT STRUCTURE REPORT form attached. Operators may use this form or any suitable alternative which contains the same information

. 3. All data and reports dealing with the Flight Safety Inspection Program shall be submitted either through a Boeing Field Service Representative or directly to:
BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT 4. All reports will be reviewed immediately.**APPENDIX A: DISCREPANT STRUCTURE REPORT** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 73 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

5. The Boeing Company will summarize the results of all reported significant data for distribution semiannually to operators and appropriate Airworthiness Authorities.

WALK-AROUND SCHEDULED MAINTENANCE 6. 5. 4. 3.

4A.

4B. AIRCRAFT DATA 2. DISCREPANT STRUCTURE REPORT

1.

STATION

MODEL A.T.A. INDEX REPORT DATA

NAME
IPC/DWG REF

COMPONENT FLIGHT CYCLES SINCE NEW COMPLETE THE FOLLOWING IF KNOWN AND DIFFERENT FROM SECTION 2: S/N

COMPLETED REPAIR DATA PLANNED

ACTION

SB
MPD
STRUCTURAL SIGNIFICANT ITEM NO.
SERVICE BULLLETINS INCORPORATED IN AREA OF DISCREPANCY

INSPECTION DATA

CORRESPONDING INSPECTION LEVELS

X 24291 ORIG. 3/84 (FRONT) 6A. WHEN DISCOVERED

OVERHAUL UNSCHEDULED SYMPTOM (FUEL/PRESS. LEAK . . . ) RELATED FLEET EXPERIENCE ACCIDENT INVESTIGATION SSID SERIES 50 6B. INSPECTION LEVEL

GENERAL VISUAL EXTERNAL SURVEILLANCE

DETAILED SPECIAL 6C. DETECTION METHOD

INTERNAL SURVEILLANCE VISUAL MAG. VISUAL DYE PENETRANT ULTRASONIC X-RAY LOW FREQUENCY EDDY CURRENT HIGH FREQUENCY EDDY CURRENT BORESCOPE MAGNETIC PARTICLE TAP TEST SOUND SMELL FEEL FUEL LEAK PRESS. LOSS SIDE 1

AIRLINE/AGENCY MONTH DAY YEAR REPORT NO.

MFG. SERIAL NO. FLIGHT HOURS SERIES TAIL NO.
FLIGHT CYCLES

COMPONENT FLIGHT HOURS SINCE NEW COMPONENT DATA (AS APPLICABLE AND AVAILABLE):

P/N
SRM REF

SINCE OVERHAUL
SINCE OVERHAUL

NO. SERVICE BULLETIN OF SERVICE BULLETIN APPLICABLE SECTION INCORPORATION DATE OF CYCLES AT INCORPORATION TOTAL FLIGHT HOURS AND

HOURS
HOURS
HOURS FLIGHTS
FLIGHTS FLIGHTS AD

OTHER (E.G., SDR, MRR) IPC SRM
SIIA SERIES 50 NO.

(COMPLETE KNOWN INFO., CHECK APPROPRIATE ITEMS FOR DISCREPANT STRUCTURE): CURRENT INSPECTION INTERVALS (FLIGHT)

SPECIAL/DIRECTED (AD, SB . . . ) REFERENCES ASSOCIATED WITH INSPECTION/REPAIR (SPECIFY NO., PAGE, FIGURE, ETC)W76755**APPENDIX A: DISCREPANT STRUCTURE REPORT** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 74 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

STRINGER Attach sketch, photos and text as required to describe defect and specific location. DISCREPANT STRUCTURE REPORT

X 2491 ORIG. 1/84 (BACK)

INSPECTED BY

ORIGINATED BY REPAIRED BY

DATE DISCREPANCY DESCRIPTION: 7. SIDE 2

associated discrepancies on the same airplane, related experience with this discrepancy on any airplane, and previous modification(s) to the discrepant structure. When applicable, give details of

TYPE OF DISCREPANCY: 7A.

LEAK DETACHED DENTED

DELAMINATED DEFORMED CRACKED CORRODED CONTAMINATED BENT

BURNED BUCKLED BROKEN

CLOGGED WORN STUCK OUT-OF-TOLERANCE MISSING LOOSE

ADJUSTED IMPROPERLY WRINKLED

SIZE OF DISCREPANCY: 7B. INCHES, OR CENTIMETERS
AREA

FINAL MEASUREMENT (IF DIFFERENT) CRACK LENGTH INITIALLY DETECTED DEPTH
DATE DATE X

7C. DISCREPANT PART: FRAME/BULKHEAD PRESSURE BULKHEAD FRAME AROUND OPENING WINDOW FORGING KEEL BEAM FLOOR

SPAR RIB

FLAP TRACK FAIRING WING CENTER SECTION WING DRY-BAY AREA/COMPT

LANDING GEAR BEAM JOINT/SPLICE LUG WELD BOND OPEN HOLE FASTENER HOLE CUTOUT

NOTCH/GROOVE DISCONTINUITY BASIC MATERIAL BUSHING PIN SKIN PLATE/PANEL CHORD NO.

STRUT/BRACE BEAM

LINK/ROD LONGERON FITTING BRACKET/SLIP STOP FASTENER ACCESS/LIGHTENING HOLE

7D. LOCATION OF DISCREPANT PART: GENERAL LOCATION (E.G., BILGE, UNDER GALLEY)

WING STA NO. BODY STA NO.

VERT STAB. STA HORIZ STAB. STA

NOSE LANDING GEAR MAIN LANDING GEAR WING LANDING GEAR BODY LANDING GEAR DOOR ACCESS PANEL RUDDER ELEVATOR AILERON FLAP SLAT SPOILER TAB (ALSO CHECK ABOVE) INTERIOR INBOARD LEFT FORWARD UPPER LEADING EDGE MIDDLE SPECIFIC LOCATION EXTERIOR OUTBOARD RIGHT AFT LOWER TRAILING EDGE SIDE NACELLE/PYLON COMPARTMENTW76756**APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 75 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS** 1. Alternate Trim Option 1: Local Lap Splice Trim Refer to the trim instructions below and Detail A for a diagram of a typical local lap splice trim. Locally trim out the upper and lower skin as shown in Detail A to remove any crack indications or discrepant fastener holes. When installing the 141U2100 Sheet 1 - 5 doublers, revise the profile of the lower external modification doubler to extend upwards into the trim area. Install 5/32 inch diameter BACR15BB( )D( ) rivets in the new fastener holes. 2. Alternate Trim Option 2: Full Lap Splice Trim in Areas With No Crew Entry Door Refer to Detail B for a trim of the entire length of the affected lap joint, from STA 400 to STA 520, on airplanes without a crew entry door in the affected area. In areas without a left or right side crew entry door, it is acceptable to trim off the entire upper skin panel lap joint from STA 400 to STA 520. If the upper skin panel is trimmed, additionally trim the upper fastener row of the lower skin panel from STA 400 to STA 520. Revise the profile of the lower external modification doubler to extend upwards into the trim area. Install 5/32 inch diameter BACR15BB( )D( ) rivets in the new fastener holes. 3. Alternate Trim Option 3: Lap Splice Trim in Areas With a Crew Entry Door Refer to Detail C for a trim of the affected lap joint, from STA 425 to STA 520, on airplanes with a crew entry door in the affected area. In areas with a left and/or right side crew entry door, it is acceptable to trim the upper skin panel lap joint from STA 425 to STA 520. If the upper skin panel is trimmed, additionally trim the upper fastener row of the lower skin panel from STA 425 to STA 520. Revise the profile of the lower external modification doubler to extend upwards into the trim area. Install 5/32 inch diameter BACR15BB( )D( ) rivets in the new fastener holes.
4. Trim Instructions:
A. Gain access to the area to be trimmed. B. Remove the fasteners from the longitudinal lap splice as necessary. C. Tape a stainless steel sheet to the fuselage skin below the damage to protect the fuselage skin.
**CAUTION:** USE CARE TO NOT GOUGE, SCRATCH, OR BUCKLE THE SKIN ADJACENT TO THE REPAIR. D. Carefully separate the bonded skins with nylon or hardwood wedges. Use a sufficient number of wedges to slowly and continuously move apart the skins to prevent buckling.
**NOTE:** To help separate the bonded skins, cold soak the joint with dry ice (solid carbon dioxide) for approximately 30 minutes. E. Carefully cut out the damaged area of the overlapped (or overlapping) skin. Use a sheet metal guard between the skins to prevent damage to the overlapping skin. Make a 0.50 inch radius at the internal and external corners of the cutout.**APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 76 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

F. Break all sharp edges of the original and repair parts 0.015 to 0.030 inch. G. Remove all nicks, scratches, gouges, burrs and sharp edges from the skin panels.**APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 77 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**NOTE:** The illustrations show a typical three row lap splice. For airplanes with a four row lap splice in the affected area, trim out all four rows common to the upper skin panel. Trim out only the upper row common to the lower skin panel.

LOWER SKIN PANEL UPPER SKIN PANEL

EDGE OF UPPER SKIN PANEL

EDGE OF LOWER SKIN PANEL

TRIM LINE (LOWER SKIN) TRIM LINE (UPPER SKIN)

TRIM LINE (UPPER SKIN)

LOWER SKIN PANEL UPPER SKIN PANEL

S-6 STA 520 STA 400

OVERSIZE HOLE LOCATIONS

EDGE OF UPPER SKIN PANEL

EDGE OF LOWER SKIN PANEL

TRIM LINE (LOWER SKIN) TRIM LINE (UPPER SKIN) A A

A A 

### A

B1419415**APPENDIX B: ALTERNATIVE LAP SPLICE TRIM INSTRUCTIONS** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 78 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

LOWER SKIN PANEL TRIM LINE (UPPER SKIN) UPPER SKIN PANEL

TRIM LINE (LOWER SKIN)



### A-A LOWER SKIN PANEL UPPER SKIN PANEL



### A-A BEFORE TRIM AFTER TRIM LOWER SKIN PANEL UPPER SKIN PANEL

S-6 STA 425 STA 520

OVERSIZE HOLE LOCATIONS

EDGE OF UPPER SKIN PANEL

EDGE OF LOWER SKIN PANEL

TRIM LINE (LOWER SKIN) TRIM LINE (UPPER SKIN)

EDGE OF CREW DOOR CUTOUT TRIM LINE (UPPER SKIN)



### A-A AFTER MODIFICATION LOWER EXTERNAL MODIFICATION DOUBLER UPPER SKIN PANEL

LOWER SKIN PANEL UPPER EXTERNAL MODIFICATION DOUBLER S-6

STRINGER A A

INBD INBD INBD 

### C1423332**APPENDIX C: EXTENSION OF THE 141U2100 MO DIFICATION DOUBLERS WHEN AN SRM REPAIR IS**  **PRESENT** Original Issue: June 02, 1988 Revision 2: October 01, 2009 747-53A2303 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 79 of 79 

### BOEING SERVICE BULLETIN 747-53A2303

**APPENDIX C: EXTENSION OF THE 141U2100 MODI FICATION DOUBLERS WHEN AN SRM REPAIR IS**  **PRESENT** Extend the 141U2100 Modification doublers in the area of a typical 747-100/200/300 SRM 53-30-03 lap splice repair. The doublers should be extended a minimum of one fastener row beyond the SRM repair fastener holes as shown. Do not end the doubler on a stringer.
**NOTE:** The three-row lap splice configuration is shown. The four-row lap splice configuration is similar.

141U2100 UPPER DOUBLER EDGE OF LOWER SKIN

LOWER SKIN UPPER SKIN TYPICAL UPPER SKIN TRIM LINE

141U2100 LOWER DOUBLER (EXTENDED INTO TRIM AREA)

NEW FASTENER HOLES EXISTING FASTENER HOLES1574622