December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 68 

### Commercial **Airplane Group**  

# 747 Service Bulletin

**Number: 747-53-2307** Date: December 21, 1989 Revision 3: April 16, 2009 ATA System: 5310 5331 **SUBJECT:** FUSELAGE - Skin - Upper Body Longitudinal Lap Joint (Stringers 23 and Above) Inspection and Repair 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1989 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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or otherwise.**BLANK PAGE** December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

BLANK PAGE**Table of Contents** December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**Table of Contents** Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 23 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 23 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 23 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 26 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 26 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM . . . . . . . . . . . . . . . . . 32 FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION . . . . . . . . . . . . . . . . . . . 38 FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS . . . . . . . . . . . . . . . . . . . . . . 48 FIGURE 4: UPPER DECK LAP JOINT INTERNAL ACCESS . . . . . . . . . . . . . . . . . . . . . . 52 FIGURE 5: MAIN DECK LAP JOINT INTERNAL ACCESS . . . . . . . . . . . . . . . . . . . . . . . 54 FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR LESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR LESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63**Table of Contents** December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

BLANK PAGEOriginal Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 68 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53-2307** 

### Revision Transmittal Sheet Original Issue: December 21, 1989 Revision 3: April 16, 2009 ATA System: 5310 5331 **SUBJECT:** FUSELAGE - Skin - Upper Body Longitudinal Lap Joint (Stringers 23 and Above) Inspection and Repair
This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** More work is necessary on airplanes changed as shown in Revision 2, Revision 1 or the original issue of this service bulletin. On lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 inches or less will be required to accomplish a structural modification as given Boeing Service Bulletin 747- 53A2463. In addition, for airplanes with the optional protruding head fastener modification installed, the repeat inspection interval has been reduced from 3,000 flight-cycles to 1,000 flight-cycles. **REASON FOR REVISION** This revision is sent to add references to 747-53A2463 for a structural modification and post modification inspections for lap joint locations where the upper (overlapping) skin thickness at the upper row of fasteners is0.071 inches or less. In addition, this revision is sent to change the repeat inspection interval from 3,000 flightcycles to 1,000 flight-cycles, for airplanes with the optional protruding head fastener modification installed. Changes to this service bulletin include: — Service Related Problem references are added to the summary section, Paragraph 1.C., Reason and Paragraph 1.J., References. — Industry Support Information is added to the Summary sections and Paragraph 2.B. — Paragraph 1.D., Description - Details to contact Boeing for structural modification information are added. — New compliance information given in Boeing Service Bulletin 747-53A2463 Revision 1 is referred to in Paragraph 1.E., Compliance. — Paragraph 1.H., Weight and Balance Changes - A statement regarding the structural modification is added. — Paragraph 3.A., General Information - Dimensions, tolerances and substitutions notes are added. — Paragraph 3.B., Work Instructions - Instructions to inspect repairs are added. References to modifications as given in Service Bulletin 747-53A2463 are added. — Notes are added throughout the service bulletin to inform operators that they should not use SRM 53-30-03, Figure 18 or 27 for a lap joint repair as these repairs do not have adequate coverage of the lap joint area. — Figure 1 and Figure 2 - Instructions to accomplish the structural modification as given in Boeing Service Bulletin 747-53A2463 are added. Figure 2 has been changed to be consistent with the logic diagrams in Figure 1. — Figure 3 - A station number in the illustration is corrected for the flight engineer’s section. — Added references to FAA AD 94-12-09, Amendment 39-8937.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

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: December 21, 1989 Revision 1: August 27, 1992 Revision 2: October 14, 1993 Revision 3: April 16, 2009Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 68 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53-2307** 

### Summary Original Issue: December 21, 1989 Revision 3: April 16, 2009 ATA System: 5310 5331 **SUBJECT:** FUSELAGE - Skin - Upper Body Longitudinal Lap Joint (Stringers 23 and Above) Inspection and Repair

**CONCURRENT REQUIREMENTS**
None. **BACKGROUND** Based on a structural review of the 747 airplane, accomplishment of the inspection program and incorporation of a select portion of the lap joint modification per this service bulletin is recommended on aging airplanes. This inspection will detect corrosion and fatigue cracks in upper body skin longitudinal lap joints caused by disbonding of the cold bond at the joint. Continued operation of an airplane that has corrosion or fatigue cracking in lap joints could lead to separation of the skin at the lap joint causing rapid decompression of the airplane. Several operators have reported corrosion, and associated bulging of skin at upper body lap joints on airplanes with 26,733 to 70,000 flight-hours. One operator reported cracking and corrosion of the lap joint at Stringer 12 from Station 1515 to 1735 and Stringer 4L at Station 1710 on an airplane with 35,134 flight-hours. One other operator reported corrosion and cracking at the lap joint at Stringer 4R, Station 1500 on an airplane with 49,024 flight-hours. Another operator reported a one inch crack at Stringer 0, Station 738 suspected to have been caused by corrosion from disbonding at the cold bonded lap joint. There have been numerous additional instances of corrosion reported at the Stringer 23 lap joint. This bulletin supersedes that portion of Service Bulletin 747-53-2157 which addresses the upper body skin longitudinal lap joints. Airplanes previously inspected per Service Bulletin 747-53-2157 require additional inspection of lap joint areas as described herein. Any lap joint areas repaired per Service Bulletin 747-53-2157 do not require further repair but an After Modification Inspection is necessary at intervals given by Revision 1 of this bulletin. This bulletin does not supersede Service Bulletin 747-53-2253 or Service Bulletin 747-53A2303 which address the upper body skin longitudinal lap joints at Stringer 6 in Section 41.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

Subsequent to previous releases of this service bulletin a review of all bulletins which recommend repeat inspections was performed to determine if the inspections were appropriate on aging airplanes. This review indicated that lap joints where the upper (overlapping) skin thickness is less than or equal to 0.071 inches should be modified at the times given in Service Bulletin 747-53A2463 on aging 747 airplanes, line numbers 1 through 200. Boeing Service Related Problem (SRP) 747OP-SRP-53-0292 is related to this service bulletin. This item is identified in Boeing Structural Item Interim Advisory (SIIA) 747-71. Federal Aviation Administration (FAA) Airworthiness Directives 90-15-06, Amendment 39-6653 and 94-12-09, Amendment 39-8937 are related to this service bulletin. **ACTION** As recommended by the 747 Structures Working Group, accomplish the inspection program per this service bulletin. In addition, do the selected portion of the lap joint modification that addresses lap joints fastened with deep countersink rivets. Incorporation thresholds for the inspection and modification are shown in the Description and Accomplishment Instructions Do a detailed external visual inspection of the upper body longitudinal lap joints at Stringers 23 and above from Station 140 to 2360 (except Stringer 6 from Station 340 to 520) within 1,000 flight-cycles after receipt of the original release of this bulletin, or before 15,000 flight-cycles have accumulated, whichever comes later. Visually inspect all lap joints for evidence of corrosion or cracking and make any necessary repair prior to further flight as given in the Accomplishment Instructions. Repeat these visual inspections at intervals not to exceed 1,000 flight-cycles for the lap joints in Sections 41, 42, and 46. Repeat the visual inspections at 2,000 flight-cycle intervals for the lap joints in Section 44. As an alternative to repeat inspections of Sections 41, 42, and 46 at 1,000 flight-cycle intervals, do an external high frequency eddy current (HFEC) inspection of selected lap joints together with the above initial visual inspection. Repeat the visual inspections at 2,000 flight-cycle intervals and the HFEC inspections in Section 41 and 42 at 4,000 flight-cycle intervals and the HFEC inspections in Section 46 at 6,000 flight-cycle intervals. For airplanes with more than 15,000 flight-cycles, within 1000 flight cycles after receipt of this service bulletin, do a external HFEC inspection of selected lap joints together with the visual inspections. Repeat the visual inspections at 2000 flight-cycle intervals and the HFEC inspections at 4,000 flight-cycle intervals in Section 41 and 42 and at 6,000 flight-cycle intervals in Section 46. On aircraft with a main deck side cargo door, extended intervals for inspection are not permitted on selected 46- section skin lap areas at Stringers 4-Left and 12-Left. Refer to the Accomplishment Instructions. On all the lap joints where the upper (overlapping) skin thickness is 0.071 inches or less, a structural modification is required at the time given in Service Bulletin 747-53A2463. If the operator’s plan is to continue with this service bulletin, rather than per the instructions in Service Bulletin 747-53A2463, based on the age of the airplane, refer to the Accomplishment Instructions for the Full or Optional Modification procedure. Do an After Modification Inspection of lap joint areas after the Full or Optional Modification. Refer to the Accomplishment Instructions for procedure and intervals for inspection. Corrosion inhibiting compound (BMS 3-23) is recommended to be applied internally to lap joint areas after Full or Optional Modification as given in the Accomplishment Instructions.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**EFFECTIVITY** 747-100, 200B and -200F 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 90-15-06 and 94-12-09 are related to this service bulletin. Boeing recommends a detailed visual inspection for all airplanes with less than 15,000 flight cycles within 1,000 flight cycles after receipt of this service bulletin. Repeat detailed visual inspections at 1,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42, and 46 and 2,000 flight cycles intervals for Section 44. This group of airplanes can elect to do the inspection for older airplanes per Method II to extend the inspection intervals. Airplanes with 15,000 or more flight cycles must do a detailed visual inspection and a High Frequency Eddy Current (HFEC) inspection within 1,000 flight cycles after receipt of this service bulletin. Repeat detailed visual inspections at 2,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42, 44 and 46. Repeat HFEC inspections at 4,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42 and 6,000 flight cycle intervals for Section 46. Section 44 does not require a HFEC inspection. Refer to Service Bulletin 747-53A2463 for new compliance information. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the configuration changes, inspections, and/or repair procedures given in this service bulletin. **MANPOWER**

**MATERIAL INFORMATION** Boeing Supplied Kits * * Kit is necessary only on airplanes with a main deck side cargo door. Refer to Paragraph 2.A., Material - Price and Availability. **Task Total Task Hours Elapsed Hours** External Visual Inspection 152 38 External HFEC Inspection 56 14 Internal Visual with LFEC Inspection (Main Deck Side Cargo Door Only) 8 8 Full or Optional Modification Refer to Paragraph 1.G., ManpowerOriginal Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

S-14 S-6

S-0 S-23 S-19 (TYPICAL) LAP JOINT SECTION 46

S-4 S-12 1480 STA 2360 STA

41 42 44

LEFT SIDE OPPOSITE RIGHT SIDE SHOWN

OF SKIN, AND MISSING OR DISTRESSED FASTENERS. ACCOMPLISH A STRUCTURAL MODIFICATION ON ALL LAP JOINTS WHERE THE UPPER (OVERLAPPING) SKIN THICKNESS IS 0.071 INCHES OR LESS AS GIVEN IN SERVICE BULLEIN 747-53A2463. INSPECT LAP JOINTS FOR CORROSION, CRACKS OR PILLOWING 140 STA 520 STA 1000 STA

SECTIONS1370319Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 68 

### Commercial **Airplanes** 

# 747 Service Bulletin

**Number: 747-53-2307** Original Issue: December 21, 1989 Revision 3: April 16, 2009 ATA System: 5310 5331 **SUBJECT:** FUSELAGE - Skin - Upper Body Longitudinal Lap Joint (Stringers 23 and Above) Inspection and Repair

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

Airplane models: 747-100 747-200B 747-200F IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER AERO CONTROLS (AEO) 1 RA722–RA723 AGES AIRCRAFT SALES & LEASING (AGJ) 1 RB004 AIR GULF FALCON (GFG) 1 RA535 RA537 **GROUP CONFIGURATION DESCRIPTION** 1 - 747-100 and -200B series airplanes, line numbers 1 through 200, with different skin thickness than airplanes in Group 3. 2 - 747-200F series airplane, line number 168. 3 - 747-100 series airplanes, line numbers 2 though 161, with different skin thickness than airplanes in Group 1.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

ALBARAKA (AAB) 1 RB102 ARKIA ISRAELI AIRLINES (ARK) 1 RA253 BANC OF AMERICA LEASING (SBC) 1 RA106 RD001–RD002 EVERGREEN A/C SALES & LEASING (EVG) 1 RA371 EVERGREEN INTERNATIONAL A/L (EVR) 3 RA028 RA631 RA633 EXPORT RESTRICTED AIRPLANES (YWV) 3 RA101–RA103 RA112 RA161–RA163 FINOVA (GRB) 1 RA651 GE (GEC) 1 RA016 GECAS (GEF) 1 RA007 RA013 RA027 JOHNSON SPACE CENTER (ZBR) 1 RA908 JUMBO JET LEASING (JJL) 1 RA526 RA532–RA534 RA539 KABO AIR (KAB) 1 RA305 RA560 KALITTA AIR (KAC) 3 RA401–RA402 RA524 RA635 RA913 LOGISTIC AIR, INC. (LGA) 1 RA217 3 RA015 RA910 NEA HOLDINGS, INC. (NEA) 1 RB001 ORIENT THAI AIRLINES (OTH) 1 RA540 UPS (UPS) 3 RA026 RA029 RA033 RA902 RA912 RA915–RA916Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

WHIRLPOOL FINANCIAL CORP. (ZZW) 1 RB005 IDENTIFICATION BY VARIABLE NUMBER **Variable Group** RA001 1 RA002 3 RA003–RA005 1 RA006 3 RA007–RA010 1 RA011 3 RA012–RA014 1 RA015 3 RA016–RA025 1 RA026 3 RA027 1 RA028–RA030 3 RA031–RA032 1 RA033 3 RA034 1 RA101–RA103 3 RA104–RA110 1 RA111–RA112 3 RA113–RA115 1 RA161–RA163 3 RA164 1 RA201–RA203 1 RA216–RA217 1 RA245–RA246 1 RA251–RA259 1 RA301–RA312 1 RA351–RA360 1 RA369–RA373 1 RA401–RA405 3 RA406–RA414 1 RA501–RA502 1 RA521–RA523 1 RA524 3 RA525–RA527 1 RA532–RA540 1Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

2. Spares Affected
None. **B. Concurrent Requirements**
None. **C. Reason** As a result of the 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 inspections and recommend selected service bulletins for incorporation on aging airplanes. This inspection program and a select portion of the lap joint modification that addresses lap joints fastened with deep countersink rivets have been recommended for accomplishment on aging 747 airplanes. RA551–RA552 1 RA559–RA561 1 RA581–RA582 1 RA585 1 RA601–RA602 1 RA631–RA635 3 RA651–RA652 1 RA671–RA677 1 RA701–RA702 1 RA721–RA724 1 RA741–RA743 1 RA761–RA762 1 RA781–RA782 1 RA901–RA902 3 RA903–RA909 1 RA910–RA916 3 RB001–RB005 1 RB041 3 RB042 1 RB043 3 RB044 1 RB071–RB075 1 RB101–RB102 1 RD001–RD002 1 RR201 2 **Variable Group**Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

This inspection will detect corrosion or cracking in upper body skin longitudinal lap joints caused by disbonding of the cold bond at the lap joint. Continued operation of an airplane that has corrosion or cracking in lap joints could lead to separation of the skin at the lap joint causing rapid decompression of the airplane. Several operators have reported corrosion, and associated bulging of skin at upper body lap joints on airplanes with 26,733 to 70,000 flight-hours. One operator reported corrosion of one to three lap joint rivets and bulging of the skin at Stringer 12 near Station 1694 on an airplane with 34,827 flight-hours. This operator also reported cracked and corroded fuselage skin with separation at the lap joint at Stringer 12 L and R at six locations each sidefrom Station 1515 to 1735 and Stringer 4L at Station 1710 on the same airplane with 35,134 flighthours. One other operator reported a corrosion bulge resulting in a skin lap crack at Stringer 4R, Station 1500 on an airplane with 49,024 flight-hours and 13,594 flight-cycles. Another operator reported a one inch skin crack starting from the lap joint at Stringer 0 near Station 738 on an airplane with 49,800 flight-hours which was suspected to have been caused by corrosion from disbonding at the cold bonded lap joint (Ref. SIIA 747-71). This operator also reported two airplanes with skin corrosion of lap joint at Stringer 4L. On one airplane, with 35,985 flight-hours, this corrosion was found at four locations between Stations 1482 and 1676. On the other airplane, corrosion was found near Stations 1510 and 1615 on an airplane with 36,461 flight-hours. Also, an operator has reported skin corrosion in the lap joint at Stringer 23R near Station 1400 on an airplane with 26,733 flight-hours and skin corrosion with bulging skin involving the lap joint at Stringer 23L between Station 1720 and 1820 on another airplane. There have been numerous additional instances of corrosion reported at the Stringer 23 lap joint. This bulletin supersedes that portion of Service Bulletin 747-53-2157 which addresses the upper body skin longitudinal lap joints. Airplanes previously inspected per Service Bulletin 747-53-2157 require additional inspection of lap joint areas as described herein. Any lap joint areas repaired per Service Bulletin 747-53-2157 do not require further repair, but an After Modification Inspection is made necessary by Revision 1 of this bulletin. Refer to the Accomplishment Instructions of this bulletin for procedure and the time interval for inspection. This bulletin does not supersede Service Bulletin 747-53-2253 or Service Bulletin 747-53A2303 which address the upper body skin longitudinal lap joints at Stringer 6 in Section 41. Boeing Service Related Problem (SRP) 747OP-SRP-53-0292 is related to this service bulletin. This item is identified in Boeing Structural Item Interim Advisory (SIIA) 747-71. Federal Aviation Administration (FAA) Airworthiness Directives 90-15-06, Amendment 39-6653 and 94-12-09, Amendment 39-8937 are related to this service bulletin.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

As a result of the 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 inspections and recommend selected service bulletins for incorporation on aging airplanes. Based on a structural review of the 747 airplane, the Structures Working Group has determined that a select portion of the lap joint modification per this service bulletin, at or before the indicated threshold, should be accomplished to support the continued structural integrity of aging 747 airplanes. Subsequent to previous releases of this service bulletin a review of all bulletins which recommend repeat inspections was performed to determine if the inspections were appropriate on aging airplanes. This review indicated that lap joints where the upper (overlapping) skin thickness is less than or equal to 0.071 inches should be modified at the times given in Service Bulletin 747-53A2463 on aging 747 airplanes, line numbers 1 through 200. Revision 1 was sent to make these changes: 1. Add an After Modification Inspection that is necessary after Full or Optional Modification. 2. Add instructions to change the terminating action for lap joints fastened with deep countersink fasteners at these locations: a. Stringer 12 from STA 520 - 740 (Line Number 59 - 200 only). b. Stringer 12 from STA 740 - 1000. c. Stringer 19 from STA 520 - 740. In these lap joints, the upper (overlapping) skin panel has a doubler hot bonded to the skin. The countersink depth of the rivet is greater than the basic skin gage. While this is not a problem for a skin panel with the hot bond intact, disbonding will result in a knife edge condition in the skin layer. This condition makes these lap joints more susceptible to fatigue cracking. Several operators have reported cracks at these lap joints. 3. Add an Optional Modification for lap joints with outer skin panel thickness of 0.090 inches or less that do not have either cracks or corrosion. 4. Add instruction to make necessary the HFEC inspection in Sections 41, 42, and 46 on airplanes with 15,000 or more flight-cycles. For these areas, the repeat HFEC inspection is necessary at 4,000 flight-cycle intervals in Section 41 and 42 and at 6,000 flight-cycle intervals in Section 46. 5. Add instruction to allow a minimum of 1.5 diameter edge margin for the skin lap joints at the top row of fastener holes on the inner skin panel for lap joints changed by the Full or Optional modification. 6. Add instruction to permit the top row of fastener holes to be oversized by 1/64 inch diameter before HFEC inspection to decrease incorrect crack indication. 7. Add instruction to recommend that corrosion inhibiting compound BMS 3-23 be applied internally to lap joints after terminating action (Full Modification). 8. Add inspection, terminating action, and oversize fastener kit for airplanes with a main deck side cargo door to Figure 6.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

9. Add reference to Aging Airplane Corrosion Prevention and Control Program D6-36022. 10. Add Figure 6 to show outer skin panel thickness at skin lap joints of 0.090 inches or less. 11. Add reference to Federal Aviation Administration (FAA) Airworthiness Directive 90-15-06, Amendment 39-6653. 12. Remove references to protruding head fasteners from the Accomplishment Instructions and from Flagnote 3 of Figure 1. The type of fasteners necessary are given by the Structural Repair Manual. 13. Remove the lap joint shown in Figure 2 in Section 44 at stringer 23 from Body Station 1000 to 1241. There is not a lap joint at this location. 14. Change Flagnote 1 of Figure 2 to show that airplanes not listed in Flagnote 1 have fay-sealed lap joints at stringer 4 in Body Section 44. 15. Instruction to contact Boeing for jacking instructions is added. Revision 2 was sent to make the following changes: 1. Add a chart in Figure 2 to assist the operator to plan the initial inspection. The chart uses station and stringer locations to identify the areas of inspection. The chart also defines the alternative inspection to extend the repeat inspection threshold for airplanes with less than 15,000 flight cycles. In addition, the chart defines the only inspection recommended for airplanes with 15,000 flight cycles or more. 2. Change to the illustrations showing the lap joint locations for Section 41. These illustrations have had the reference to Str 6 removed from the detail because service bulletins 747-53-2253 and 747-53A2303 show inspections and repair at Str 6. The station callout for Str 0 is changed to reflect the correct starting point for the inspections. The tables showing the lap joint locations have also been revised to remove Str 6 information and to correct the starting point for Str 0. 3. Add a Compliance statement to the Summary information and to Section I, D in the service bulletin. 4. Remove redundant information in Figure 1 logic diagram for Inspection Method II. 5. Change the flight cycle threshold in Flag note 5 of Figure 1. The change brings the statement in accord with the 747 Aging Fleet Structures Working Group recommendation and the flight cycle threshold in the first paragraph of the Description. Revision 3 is sent to add a structural modification and post modification inspections for lap joint locations where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 inchesor less. In addition, this revision is sent to change the repeat inspection interval from 3,000 flightcycles to 1,000 flight-cycles, for airplanes with the optional protruding head fastener modification installed. Changes to this service bulletin include: — Service Related Problem references are added to the summary section, Paragraph 1.C., Reason and Paragraph 1.J., References. — Industry Support Information is added to the Summary sections and Paragraph 2.B.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

— Paragraph 1.D., Description - Details to contact Boeing for structural modification information are added. — New compliance information given in Boeing Service Bulletin 747-53A2463 Revision 1 is referred to in Paragraph 1.E., Compliance. — Paragraph 1.H., Weight and Balance Changes - A statement regarding the structural modification is added. — Paragraph 3.A., General Information - Dimensions, tolerances and substitutions notes are added. — Paragraph 3.B., Work Instructions - Instructions to inspect repairs are added. References to modifications as given in Service Bulletin 747-53A2463 are added. — Notes are added throughout the service bulletin to inform operators that they should not use SRM 53-30-03, Figure 18 or 27 for a lap joint repair as these repairs do not have adequate coverage of the lap joint area. — Figure 1 and Figure 2 - Instructions to accomplish the structural modification as given in Boeing Service Bulletin 747-53A2463 are added. Figure 2 has been changed to be consistent with the logic diagrams in Figure 1. — Figure 3 - A station number in the illustration is corrected for the flight engineer’s section. — Added references to FAA AD 94-12-09, Amendment 39-8937. **D. Description** Subsequent to previous releases of this service bulletin a review of all bulletins which recommend repeat inspections was performed to determine if the inspections were appropriate on aging airplanes. This review indicated that lap joints where the upper (overlapping) skin thickness is less than or equal to 0.071 inches should be modified at the times given in Service Bulletin 747-53A2463 on aging 747 airplanes, line numbers 1 through 200. Refer to Service Bulletin 747-53A2463 to determine whether to continue with the instructions in this service bulletin or with the instructions in Service Bulletin 747- 53A2463. Based on a structural review of the 747 airplane, it is recommended that the inspection program be accomplished per this service bulletin. A select portion of the lap joint modification that addresses lap joints fastened with deep countersink rivets per the Accomplishment Instructions should be accomplished prior to, or upon accumulation of 20,000 flight cycles or within 1000 flight cycles after receipt of Revision 1 of this service bulletin, whichever is later. Within 1,000 flight-cycles after receipt of this bulletin, a detailed external visual inspection is done at the upper body longitudinal lap joints at Stringers 23 and above from Station 140 to 2360 (except Stringer 6 from Station 340 to 520). A visual inspection is done at all lap joints for evidence of corrosion or cracking and any necessary repair is done as given in the Accomplishment Instructions prior to further flight. These visual inspections are repeated at intervals not to exceed 1,000 flight-cycles for the lap joints in Sections 41 (Station 140 - 520), 42 (Station 520 - 1000), and 46 (Station 1480 - 2360). Visual inspections are repeated at 2,000 flight-cycle intervals for the lap joints in Section 44 (Station 1000 - 1480). As an alternative to repeat inspections of Sections 41, 42, and 46 at 1,000 flight-cycle intervals, external high frequency eddy current (HFEC) inspection can be done at selected lap joints together with the above initial visual inspection. The visual inspection is repeated at 2,000 flight-cycle intervals and the HFEC inspection in Section 41 and 42 at 4,000 flight-cycle intervals and the HFEC inspection in Section 46 at 6,000 flight-cycle intervals.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

For airplanes with 15,000 flight-cycles or more, within 1000 flight cycles after receipt of this service bulletin, do an external HFEC inspection of selected lap joints together with the visual inspections.Repeat the visual inspections at 2000 flight cycle intervals and the HFEC inspections at 4,000 flightcycle intervals in Section 41 and 42 and at 6,000 flight-cycle intervals in Section 46. On aircraft with a main deck side cargo door, extended intervals for inspection are not permitted on selected 46-section skin lap areas at Stringers 4-Left and 12-Left. Refer to the Accomplishment Instructions. In lieu of continued reinspections, terminating action can be done by a Full Modification or by an Optional Modification. The Full Modification is accomplished when an uncorroded lap joint area is separated between adjacent circumferential splices, adhesive removed, protective finish and faying surface sealant is applied, and joint is refastened per 747 Structural Repair Manual Subject 53-30-03. Terminating action in a corroded or cracked lap joint area may be accomplished when the area is repaired per 747 Structural Repair Manual Subject 53-30-03. For the Full Modification in Section 42 only, repair of deep countersink fasteners at selected lap joints is made necessary by Revision 1 as given in the Accomplishment Instructions. An Optional Modification is permitted at selected lap joint areas with outer skin panel thickness of 0.090 inches or less that do not have either cracks or corrosion. For the Optional Modification, the countersunk fasteners are replaced in only the top row of the lap joint with 1/16 inch diameter oversize protruding head fasteners. Corrosion inhibiting compound (BMS 3-23) must be applied internally to lap joints after Optional Modification. An open hole HFEC inspection is necessary before fastener installation. This Optional Modification is not permitted at the lap joints with deep countersink fasteners located in Section 42. It is recommended that this service bulletin be accomplished concurrently with service bulletins 747- 53A2265, 747-53-2272, 747-53A2279, 747-53-2305, and 747-53A2463 due to common access. Airplanes modified per the initial release of this service bulletin do require more work. As a result of Rev 1, an after modification inspection will be required.
**NOTE:** For lap joints with an upper (overlapping) skin thickness equal to or less than 0.071 inches blend out damage that is less than 10% of the original thickness. Repair damage greater than 10% of the original thickness per SRM 53-30-03 Fig. 19. If the damaged area is more than the specified limits in SRM 53-30-03 Fig. 19, contact Boeing for repair instructions. SEND TO: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT To define the repair for each lap joint, the structural condition of the adjacent skin, the location of the damage, the dimensions of the damage, and existing local repairs must be known. Because of these reasons, it is likely that unique repair drawings will be needed to define the terminating action for each airplane by Service Bulletin 747-53A2463. Federal Aviation Administration (FAA) Airworthiness Directives 90-15-16, Amendment 39-6653 and 94-12-09, Amendment 39-8937 are related to this service bulletin. This service bulletin is listed in Boeing Document D6-35999.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

Revision 3 - More work is necessary on airplanes changed as shown in Revision 2, Revision 1 or the original issue of this service bulletin. On lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 inches or less will be required to accomplish a structural modification as given Boeing Service Bulletin 747-53A2463. In addition, for airplanes with the optional protrudinghead fastener modification installed, the repeat inspection interval has been reduced from 3,000 flightcycles to 1,000 flight-cycles. **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 90-15-06 and 94-12-09 are related to this service bulletin. Boeing recommends a detailed visual inspection for all airplanes with less than 15,000 flight cycles within 1,000 flight cycles after receipt of this service bulletin. Repeat detailed visual inspections at 1,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42, and 46 and 2,000 flight cycles intervals for Section 44. This group of airplanes can elect to do the inspection for older airplanes per Method II to extend the inspection intervals. Airplanes with 15,000 or more flight cycles must do a detailed visual inspection and a High Frequency Eddy Current (HFEC) inspection within 1,000 flight cycles after receipt of this service bulletin. Repeat detailed visual inspections at 2,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42, 44 and 46. Repeat HFEC inspections at 4,000 flight cycle intervals on non-terminated lap joints in Sections 41, 42 and 6,000 flight cycle intervals for Section 46. Section 44 does not require a HFEC inspection. Longitudinal lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches will require accomplishment of a structural modification or a second modification, and post modification inspections at the times given in SB 747-53A2463 Revision 1 "FUSELAGE - Skin - Longitudinal Lap Joints Inspection and Repair", Paragraph 1.E., Compliance, Table 3. SB 747-53A2463 Revision 1 includes instructions for accomplishing the structural modification. **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.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

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, repair, and modification procedures of this service bulletin as an AMOC to the corresponding requirements of paragraph A., B., and F. of AD 90-15-06. 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 H. of the AD. All provisions of AD 90-15-06 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 applicable inspection, repair, and modification procedures of this service bulletin as an AMOC to the corresponding requirements of paragraphs (a), (b), (c), (e), (f) and (g) of AD 94-12-09. 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 (i) of the AD. All provisions of AD 94-12-09 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. **Task Number of Persons Task Hours Elapsed Hours** Visual Inspection of Lap Joints 4 152 38 Eddy Current Inspection of Lap Joints 4 56 14
TOTAL FOR EACH AIRPLANE 208 52 (a) Crew size, man hour and elapsed time shown does not include time for lap joint repair or access to accomplish such repair since it is dependent on the extent of repairs required. It is assumed that operators will not perform terminating action on all lap joint areas at one time. Therefore, crew size, man hours and elapsed time should be based on operator's experience and on the length and location of the lap joint for which terminating action is accomplished. Accomplishment of terminating action is estimated to be 96 man hours for each 200 inch length of uncracked and uncorroded lap joint.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

The following breakdown of manpower requirements is suggested as a guide to assist operators in planning and accomplishing this modification on airplanes with Main Deck Side Cargo Door (MDSCD) Modification. This estimate is for direct labor performed by an experienced crew. It does not include setup, planning, familiarization, cure time, part fabrication, tool acquisition, or lost time. Factor this estimate as necessary based on your own experience.

**H. Weight and Balance Changes** Installation of lap joint repairs and modifications as outlined in Boeing Service Bulletin 747-53A2463 "Fuselage - Skin - Longitudinal Lap Joints Inspection and Repair" will affect the weight and balance of the airplane. Determination of these changes is necessary, once the configuration of the lap joint repairs and modifications are defined. **I. Electrical Load Data** Not applicable. **J. References** 1. Existing Data: a. Service Related Problem (SRP) 747OP-SRP-53-0292 b. 747 Maintenance Manual (AMM) Subject 25-11-01, 25-11-02, 25-11-03, 25-11-05, 25-14- 01, 25-19-00, 25-21-01, 25-21-02, 25-21-04, 25-21-12, 25-22-01, 25-22-03, 25-22-06, 25- 23-01, 25-23-04, 25-23-05, 25-24-00, 25-24-05, 25-24-11, 25-24-12, 25-24-19, 25-25-01, 25-25-03, 25-25-04, 25-26-02, 25-26-03, 25-26-06, 25-27-00, 25-28-01, 25-28-15, 25-28- 23, 25-31-04, 25-40-01, 25-40-03, 25-59-01, 25-68-02, 31-00-00, 34-11-00, 35-00-00, 35- 21-00, 52-11-01, 52-13-01, 52-51-01, 53-21-01, 53-21-02 c. 747 Structural Repair Manual (SRM) Subject 51-10-01, 53-30-03 d. 747 Nondestructive Test (NDT) Manual D6-7170, Part 6, Subjects 51-00-00, 53-30-00, 53- 30-02, 53-30-03, 53-30-05, 53-30-09, and 53-30-19 e. 747 Structural Item Interim Advisory (SIIA) 747-71 f. Boeing Service Bulletins 747-53-2157, "Body Longitudinal Skin Lap Joints, Tear Strap/Skin Lap Splices, Window Forgings, Skin Panel Doublers, And Selected Skin Panel Corrosion Inspection"; 747-53-2253, "Fuselage - Nose Section - Station 340 to 400 Stringer 6 Skin Inspection and Modification"; 747-53A2265, "Fuselage - Nose Section 41 - Body Frame Structure Inspections and Crack Repairs"; 747-53A2279, "Fuselage - Skin - Upper Body Skin Bonded Tear Strap Inspection and Modification"; 747-53A2303, "Fuselage - Nose Section - Station 400 to 520 Stringer 6 Skin Lap Splice Inspection Repair and Modification" 747-53A2463 "Fuselage - Skin - Longitudinal Lap Joints Inspection and Repair" **Task Number of Persons Task Hours Elapsed Hours** Internal Visual Inspection and Low Frequency Eddy Current Inspection (MDSCD Mod) 188Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

g. FAA Airworthiness Directive (AD) 90-15-06, Amendment 39-6653 and 94-12-09, Amendment 39-8937. h. Boeing Document D6-36022, "Aging Airplane Corrosion Prevention and Control Program, Model 747. i. Boeing Document D6-35999, "Aging Airplane Service Bulletin Structural Modification Program, Model 747". 2. Data supplied with this Service Bulletin: a. Drawings:

3. Installation Drawings Used in the Preparation of this Service Bulletin:
None. **K. Publications Affected**

**L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

**Drawing Number Title Sheet DCN ADCN** 015U0566 Replacement Fastener Instl - Lap Splice Rework, Sta. 1656 to Sta. 2002 Str 4L and Str 12L - Top Kit P/L (a) A - 1 (a) - - 2 (a) - - (a) Drawings sent with Revision 1 of this service bulletin.

**Publication Chapter-Section** 747 Corrosion Prevention Manual 53-30-47Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

BLANK PAGEDecember 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**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.

Date: August 27, 1992 The kits are subject to the terms and conditions of Boeing's standard purchase order acknowledgment. The prices (and ROLT) are subject to acceptance within 180 days from the date shown above. After 180 days, 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 configuration changes, inspection, and/or repair procedures given in this service bulletin. **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. **Kit Number Name ROLT**  **(Weeks) Unit Price** 015U0566-1 Replacement Fastener Instl-Lap Splice Rework, Sta 1656 to Sta 2002, S-4L and S-12L, Top Kit 42 $5927.00December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**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.

2. Parts and Materials Supplied by the Operator:
None. 3. Parts Modified and Reidentified:
None. 4. Parts Removed and Not Replaced:
None. **D. Parts Necessary to Change Spares**
None **E. Special Tooling - Price and Availability**
None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. **015U0566- Replacement Fastener Instl. - Lap Splice Rework, Sta 1656 to Sta 2002 Str 4L to Str 12L - Top Kit** 

**New Part Number QTY**  **Name Notes -1**  015U0566 - Top Kit (a) (b) (c) (d) (a) This kit is for airplanes with Main Deck Side Cargo Door Modification only. This kit contains fasteners to accomplish the full modification from Sta 1656 to Sta 2002 at Str 4L and Str 12L only. (b) See sheet PL of drawing 015U0566, supplied with this service bulletin, for kit contents. (c) This kit has more parts than necessary for installation. Discard or save parts not used. (d) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 012W6100 are used to determine the part numbers used as substitutes.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**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. The following paragraphs outline the general accomplishment instructions. The suggested sequence of operations and detailed accomplishment instructions are indicated by circle notes on the figures. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Figure 1 contains the Logic Diagram presentations of the following general accomplishment instructions. 4. Lap joints on cargo door are not required to be inspected or modified on aircraft with Main Deck Side Cargo Door. 5. As recommended by the 747 Aging Fleet Structures Working Group, accomplish the inspection program per this service bulletin. In addition, do the selected portion of the lap joint modification that addresses lap joints fastened with deep countersink rivets. Incorporation thresholds for the inspection and modification are shown in the Description and Accomplishment Instructions 6. To accomplish the Full or Optional Modification on lap joints where the upper (overlapping) skin panel thickness is 0.090 inches or less, a HFEC inspection on some fastener holes is required. Figure 6 identifies the locations where the upper (overlapping) skin panel thickness is 0.090 inches or less. Lap joints where the upper (overlapping) skin panel thickness is 0.071 inches or less require an after modification inspection. Figure 7 identifies the locations where the upper (overlapping) skin panel thickness is 0.071 inches or less. 7. In some areas of the lap joints, a doubler is bonded to the upper (overlapping) skin panel. The skin panel thicknesses used in Figure 6 and Figure 7 do not include doublers. The thickness dimension used in Figure 6 and Figure 7 are for skin panels only. The modifications and after modification inspections are based on skin panel thickness only. 8. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 9. 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 SRM, Chapter 51Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

— Torque limits to tighten nuts and bolts are given in 747 SRM, Chapter 51. 10. 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. 11. 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. **B. WORK INSTRUCTIONS** 1. For all lap joints affected by this bulletin as identified by Figure 2, perform inspection of the lap splices using Method I or II as outlined in the logic diagrams of Figure 1. Method I: Visual Inspection only (Do not use for airplanes with more than 15,000 flight cycles) Within 1,000 flight-cycles after receipt of the original release of this bulletin, do a detailed visual inspection of the affected lap joints per Figure 2, circle notes 1 and 3. Repair any corrosion beyond limits or cracking as specified in Figure 2, circle note 3. Repeat the detailed visual inspection at intervals not to exceed 1,000 flight-cycles for the nonterminated lap joints in Sections 41, 42, and 46. Repeat the detailed visual inspection at intervals not to exceed 2,000 flight-cycles in Section 44. Method II: Visual and Eddy Current Inspection (Required for airplanes with 15,000 or more flight cycles, optional for airplanes with less than 15,000 flight cycles) Within 1,000 flight-cycles after receipt of the original release of this bulletin, do a detailed visual inspection of the affected lap joints per Figure 2, circle notes 1 and 3. At the same time do an external high frequency eddy current (HFEC) inspection of selected lap joints as indicated in Figure 2, circle notes 2 and 3. Repair any corrosion beyond limits or cracking as specified in Figure 2, circle note 3. Repeat the detailed visual inspections at intervals not to exceed 2,000 flight-cycles in Sections 41, 42, 44, and 46. Repeat the HFEC inspections at intervals not to exceed 4,000 flight-cycles for the nonterminated lap joints in Sections 41 and 42 and intervals not to exceed 6,000 flight-cycles for the nonterminated lap joints in Section 46. Eddy Current inspections are not required for lap joints in Section 44. On aircraft with a main deck side cargo door, do an internal low frequency eddy current (LFEC) inspection per 747 Non Destructive Test Manual D6-7170, Part 6, Subject 53-30-09 on selected 46-section skin lap areas at Stringer 4-left and 12-left together with the above initial visual inspections. 2. In lieu of continued reinspections, modification of lap joint areas shown in Figure 2 is accomplished as follows:Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**NOTE:** 1. At laps where the upper (overlapping) skin thickness is 0.071 inch or less, Boeing recommends that operators accomplish the structural modification as given in Boeing Service Bulletin 747-53A2463, "Fuselage - Skin - Longitudinal Lap Joints Inspection and Repair". Refer to the compliance table in Paragraph 1.E. of Service Bulletin 747-53A2463 to determine whether to continue with the instructions in this service bulletin or to accomplish the modification given in Service Bulletin 747- 53A2463. 2. The optional modification should not be accomplished at lap joint locations where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 inches or less. 3. Do not use 747-100/200/300 SRM 53-30-03 Figure 18 or 27 when accomplishing a lap joint repair. 747-100/200/300 SRM 53-30-03 Figure 19 should be used for lap joint repairs. 4. Figure 7 shows the locations of all lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches. a. Full modification in an uncorroded lap joint is accomplished when the lap joint is separated along an entire skin panel between adjacent circumferential splices, adhesive is removed, faying surface sealant is applied and the joint is refastened per 747 Structural Repair Manual Subject 53-30-03 Figure 9 or Figure 10 as applicable. This does not apply to deep countersink fastener locations. See following procedure for deep countersink fastener modification. b. Full modification in the area of deep countersink rivets, Str 12, Sta 520 to Sta 1000 and Str 19, Sta 520 to Sta 740, must be accomplished by the following method. Separate the lap joint between adjacent circumferential splices and remove adhesive to inspect for corrosion or cracks. Do a HFEC open hole inspection of all fastener locations per 747 Non Destructive Test Manual D6-7170 Part 6, Subject 53-30-00 Figure 1,3 or 4. At rivet locations, drill to oversize dimension of 0.284-0.296. Apply fay surface sealant to the lap joint to fill the remaining countersink void, and install 9/32 protruding head fasteners in all three fastener rows in lap joint. All bolt locations in lap joint area are to be reworked per 747 Structural Repair Manual Subject 53-30-03, Fig. 10. c. Full modification in a corroded lap joint is accomplished when a permanent repair of corroded lap joint area is conducted per 747 Structural Repair Manual Subject 53-30-03 concurrently with full modification of the remaining part of the lap joint per step 3.a. If the amount of material removed exceeds 10 percent, trim the affected area and repair per SRM. At the same time inspect the body frame in the corroded area and repair any frame cracking per Structural Repair Manual Subject 51-40-03.
**NOTE:** Do not use 747-100/200/300 SRM 53-30-03 Figure 18 or 27 when accomplishing a lap joint repair. 747-100/200/300 SRM 53-30-03 Figure 19 should be used for lap joint repairs.Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

d. Modification in a lap joint that is both corrosion and crack free is accomplished by either the full modification per step 3.a. or an optional modification. The optional modification consists of replacing existing countersunk fasteners, in areas where the upper (overlapping) skin panel thickness is 0.090 or less, with 1/16 inch oversized protruding head fasteners in the lap joint upper fastener row without disturbing the rest of the lap joint. e. Full modification of the lap joints around the Main Deck Side Cargo Door (MDSCD) modification can be accomplished by the following method. Remove the straps and doublers at Str 4, Sta 1660 to Sta 2000. Remove doublers from Str 12, Sta 1741 to Sta 1780, Sta 1920 to Sta 1961. Full modification of the lap joints forward of Sta 1741 and aft of Sta 1961 can be accomplished. After full modification of Str 4 and Str 12 in this area, reinstall straps and doublers using the special kit of oversize fasteners. Refer to drawing 015U0566, PL, Sh 1 and Sh 2. For both Full and Optional Modifications on lap joints where the upper (overlapping) skin panel thickness is 0.090 inches or less, a HFEC inspection of some fastener holes is required. Do an open hole HFEC inspection in the upper fastener row of lap joint per 747 Non Destructive Test Manual D6-7170 Part 6, 53-30-00 Figure 1, 3 or 4 for countersunk holes or 51-00-00 Figure 1 or 11 for non countersunk holes to verify holes are crack free. For both full and optional modifications it is acceptable to oversize holes in upper fastener row by 1/64 inch to decrease incorrect crack indication. After inspection, enlarge holes again by 3/64 inch to permit installation of 1/4 inch protruding head fasteners. See Figure 6 for upper (overlapping) skin panels 0.090 thickness or less. The HFEC inspection is not required on lap joints where the upper (overlapping) skin panel thickness is greater than 0.090 inches. Conduct both an internal and external detailed visual inspection for cracking and corrosion of the lap joint prior to the modification. Apply corrosion prevention compound BMS 3-23, at time of modification, to the lap joint externally under the wing to body fairing and internally at all lap joint areas. **NOTE:** 1. When accomplishing terminating action on a specific lap joint length, contact Boeing for jacking requirements (specify lap joint being reworked, details of airplane configuration including weight and CG, and any other work being performed concurrently on the airplane). Lap joint must be opened completely between circumferential splices. No partial lap joint rework is allowed. 2. To accomplish terminating action with either the full or optional modification, the standard 2 dia. edge margin requirement is changed to 1.5 dia minimum at the top row of fasteners on the inner skin panel of all lap joints. 3. Apply corrosion inhibiting compound (BMS 3-23 or equivalent) internally to all lap joint areas after terminating action is accomplished. Affected lap joints for which inspection or terminating action has been accomplished by previous release of this service bulletin do not require additional work for application of corrosion inhibiting compound. Application of corrosion inhibiting compound is mandatory for airplanes repaired by the optional modification. 3. Restore airplane to normal configuration. 4. After modification reinspect as follows:Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 31 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

a. External HFEC inspection for skin cracks at the upper fastener row of the lap joint (0.071 and less upper (overlapping) skin thicknesses only) per 747 NDT, Part 6, 53-30-19 (preferred) or 747 NDT, Part 6, 51-00-00 Figure 4. See Figure 7 for areas of the lap joints that require reinspection. — at 10,000 flight cycles after full modification per Revision 1 or later revision; — at 7000 flight cycles after optional modification; — at 5000 flight cycles for Sec. 42 deep countersink fastener locations reworked per the original release of this service bulletin; Repeat at 1,000 flight cycle intervals (applicable to all modification methods). Post-modification inspections per this service bulletin at lap joints with upper (overlapping) skin thickness of 0.071 inch or less at the upper fastener row can be terminated after thestructural modification given in Service Bulletin 747-53A2463 has been done. Postmodification inspection data for lap joints with upper (overlapping) skin thickness of 0.071 inch or less at the upper fastener row will be included with the structural modification data given as part of the Service Bulletin 747-53A2463 requirements. b. Detailed visual inspection for corrosion per Boeing Document D6-36022. External at 5 year intervals Internal at 8 year intervals with application of corrosion inhibiting compound. c. If any corrosion or cracks are found, repair per 747 Structural Repair Manual Subject 53-30-03, notify Boeing of the details of the discrepancy and continue inspection per steps 4.a. and 4.b. above. **NOTE:** Do not use 747-100/200/300 SRM 53-30-03 Figure 18 or 27 when accomplishing a lap joint repair. 747-100/200/300 SRM 53-30-03 Figure 19 should be used for lap joint repairs. 5. Inspect repairs as given in 747-100/200/300 SRM 53-30-03 or as given in the 747 Repair Assessment Guidelines document D6-36181. For any external doubler repairs greater than 40 inches in length (in the horizontal direction) do internal surface HFEC inspections every 3,000 flight-cycles.**FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 32 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**

INSPECTION METHOD I: VISUAL ONLY

(DO NOT USE FOR AIRPLANES WITH 15,000 OR MORE FLIGHT-CYCLES) WITHIN 1,000 FLIGHT CYCLES AFTER RECEIPT OF THIS BULLETIN PERFORM THE FOLLOWING

CONDUCT A DETAILED EXTERNAL VISUAL INSPECTION TO DETERMINE IF CORROSION OR CRACKING EXISTS AT COLD-BONDED LONGITUDINAL BODY SKIN LAP JOINTS AT S-23 AND ABOVE FROM STATION 140 TO 2360 (REF FIGURE 2)

AREAS OF CRACKS OR CORROSION NO CRACKS OR CORROSION
CONDUCT HFEC INSPECTION FOR CRACKS AT UPPER FASTENER ROW OF LAP JOINT OVER COMPLETE LENGTH OF LAP JOINT AS INDICATED IN FIGURE 2 CONDUCT TERMINATING ACTION ON AFFECTED LAP JOINTS

DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS) REPEAT VISUAL INSPECTION OF ALL NONTERMINATED LAP JOINTS IN SECTIONS 41,42AND 46 AT 1,000 FLIGHTCYCLE INTERVALS AND SECTION 44 AT 2,000 FLIGHTCYCLE INTERVALS CORROSION BUT NO CRACKS CRACKS

DETERMINE AMOUNT OF MATERIAL LOSS PER LFEC INSPECTION METHOD IN 747 NDT D6-7170, PART 6, 51-00-00, FIGURE 5 OR FIGURE 12

CONTINUED ON NEXT PAGE 5 1

2

3

A B C D1370326

**(SHEET 1 OF 6) FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 33 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

AT 5,000 FLIGHT-CYCLES FOR DEEP COUNTERSINK RIVETS REWORKED PER ORIGINAL RELEASE DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS) CONDUCT TERMINATING ACTION ON REMAINDER OF LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES WITHIN 15 MONTHS

DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS)

AT 7,000 FLIGHT-CYCLES AFTER OPTIONAL MODIFICATION AT 10,000 FLIGHT-CYCLES AFTER FULL MODIFICATION

EXTERNAL HFEC INSPECTIONS FOR CRACKS AT THE UPPER FASTENER ROW OF THE LAP JOINT PER THE 747 NDT MANUAL MATERIAL LOSS LESS THAN 10% MATERIAL LOSS GREATER THAN 10%

CONDUCT TERMINATING ACTION ON

30 MONTHS CORRODED LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES WITHIN CORRODED JOINTS BETWEEN

INTERVALS REPEAT INSPECTION OF CIRCUMFERENTIAL SPLICES AT 500 FLIGHT-CYCLE FLIGHT CORROSION PER SRM 53-30-03 PRIOR TO FURTHER PRESSURIZED REPAIR ALL CRACKS OR

THEN WITHIN 1,000 FLIGHT-CYCLES FROM LAST EXTERNAL HFEC INSPECTION C D B A CONTINUED FROM PREVIOUS PAGE

4

3 3 61370333

**(SHEET 2 OF 6) FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

INSPECTION METHOD II: VISUAL AND EDDY CURRENT INSPECTION (REQUIRED FOR AIRPLANES WITH 15,000 OR MORE FLIGHT-CYCLES) WITHIN 1,000 FLIGHT-CYCLES AFTER RECEIPT OF THIS BULLETIN PERFORM THE FOLLOWING
CONDUCT A DETAILED EXTERNAL VISUAL INSPECTION TO DETERMINE IF CORROSION OR CRACKING EXISTS AT COLD-BONDED LONGITUDINAL BODY SKIN LAP JOINTS AT S-23 AND ABOVE FROM STATION 140 TO 2360 (REF FIGURE 2) CONDUCT AN EXTERNAL HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF SELECTED LAP JOINTS IN SECTIONS 41, 42 AND 46 FOR SKIN CRACKING AS INDICATED IN FIGURE 2

NO CRACKS OR CORROSION

CONDUCT TERMINATING ACTION ON AFFECTED LAP JOINTS
DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS) REPEAT VISUAL INSPECTION OF ALL NONTERMINATED LAP JOINTS IN SECTIONS 41,42, 44 AND 46 AT 2,000 FLIGHT CYCLE INTERVALS; REPEAT HFEC INSPECTIONS AT 4,000 FLIGHT-CYCLES FOR SECTIONS 41 AND 42, 6,000 FLIGHT-CYCLES FOR SECTION 46 CRACKS CORROSION BUT NO CRACKS

DETERMINE AMOUNT OF MATERIAL LOSS PER LFEC INSPECTION METHOD IN 747 NDT D6-7170, PART 6, 51-00-00, FIGURE 5 OR FIGURE 12 1 5

2

3

A
CONTINUED ON NEXT PAGE B C D1370334

**(SHEET 3 OF 6) FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

The instruction numbers shown below agree with the numbers shown inside the flag symbols in FIGURE 1. 1. A "CYCLE" IS A FLIGHT CYCLE WITH CABIN PRESSURE DIFFERENTIAL GREATER THAN 2.0 PSID. DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS) DO POST MODIFICATION INSPECTION (SKIN GAGE 0.071 OR LESS)

AT 10,000 FLIGHT-CYCLES AFTER FULL MODIFICATION AT 5,000 FLIGHT-CYCLES FOR DEEP COUNTERSINK RIVETS REWORKED PE RORIGINAL RELEASE AT 7,000 FLIGHT-CYCLES AFTER OPTIONAL MODIFICATION

EXTERNAL HFEC INSPECTIONS FOR CRACKS AT THE UPPER FASTENER ROW OF THE LAP JOINT PER THE 747 NDT MANUAL

THEN WITHIN 1,000 FLIGHT-CYCLES FROM LAST EXTERNAL HFEC INSPECTION MATERIAL LOSS LESS THAN 10%

REPEAT INSPECTION OF CORRODED JOINTS BETWEEN CIRCUMFERENTIAL SPLICES AT 500 FLIGHT-CYCLE INTERVALS

CONDUCT TERMINATING ACTION ON CORRODED LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES WITHIN 30 MONTHS MATERIAL LOSS GREATER THAN 10%

REPAIR ALL CRACKS OR CORROSION PER SRM 53-30-03 PRIOR TO FURTHER PRESSURIZED FLIGHT

CONDUCT TERMINATING ACTION ON REMAINDER OF LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES WITHIN 15 MONTHS 4

3 3 6 A CONTINUED FROM PREVIOUS PMAGE

B C D1370338

**(SHEET 4 OF 6) FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

2. EXTERNALLY, EVIDENCE OF CORROSION IN CLUDES SKIN PILLOWING OR BULGES BETWEEN FASTENERS; WHITE POWDER PROTRUDING FROM LAP JOINT; LOOSE, MISSING OR DISTRESSED FASTENER HEADS; SKIN CRACKS; OR CORROSION THROUGH THE SKIN AS SHOWN IN NOTES 1 AND 2. SKIN PILLOWING IN EXCESS OF 0.010 INCH IS CONSIDERED EVIDENCE OF CORROSION. AS AN ALTERNATIVE TO MEASURING PILLOWING OF SKIN AND VISUAL INSPECTION FOR DISTRESSED FASTENERS, EDDY CURRENT INSPECTION PER 747 NON DESTRUCTIVE TEST MANUAL D6 7170, PART 6, 51- 00-00, FIGURE 5 MAY BE USED TO MEASURE THE EXTENT OF MATERIAL LOSS IN THE LAP JOINT.
**NOTE:** 1. Distressed fasteners are evidenced by cracking of the fastener head, dishing of fastener head or excessive countersink depth. Refer to the ’Distressed Fastener Examples’ illustration at the end of this Figure. 2. Measuring of pillowing is accomplished by using a suitable straight edge and thickness gage. Minimum length of straight edge should be 4.50 inches. Refer to the ’Pillowing Example’ illustration at the end of this Figure. 3. TERMINATING ACTION HAS A CHOICE OF PROCEDURES. FULL MODIFICATION: FULL MODIFICATION CONSISTS OF OPENING THE LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES, REMOVING ADHESIVE, REPAIRING ALL CRACKS AND CORROSION, AND REASSEMBLING LAP JOINT PER SRM SUBJECT 53-30-03 FIG 9 AND 10. FULL MODIFICATION FOR DEEP COUNTERSINK FASTENER LOCATIONS AT STR 12 STA 520 - 1000 AND STR 19 STA 520 - 740 CONSISTS OF OPENING THE LAP JOINT BETWEEN CIRCUMFERENTIAL SPLICES, REMOVING ADHESIVE, REPAIRING ALL CRACKS AND CORROSION, AND REASSEMBLING THE LAP JOINT WITH 9/32 INCH PROTRUDING HEAD FASTENERS IN ALL FASTENER LOCATIONS. THIS IS THE ONLY ACCEPTABLE MOD FOR DEEP COUNTERSINK FASTENERS AND GIVES THE OPERATOR FULL MOD STATUS ON POST MOD INSPECTION SCHEDULE. OPTIONAL MODIFICATION: OPTIONAL MODIFICATION CONSISTS OF REMOVING THE UPPER ROW OF FASTENERS AT A CORROSION FREE LAP JOINT, HFEC OPEN HOLE INSPECT FOR CRACKS IN REMOVED FASTENER LOCATIONS, AND INSTALLING 1/4 INCH PROTRUDING HEAD FASTENERS. THE OPTIONAL MODIFICATION IS NOT APPLICABLE TO DEEP COUNTERSINK FASTENER LOCATIONS.
**NOTE:** 1. Longitudinal lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches will require accomplishment of a structural modification or a second modification, and post modification inspections at the times given in SB 747-53A2463 Revision 1 "FUSELAGE - Skin - Longitudinal Lap Joints Inspection and Repair", Paragraph 1.E., Compliance. 2. The optional modification should not be accomplished at lap joint locations where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 inches or less. 3. Figure 7 shows the locations of all lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches.

**(SHEET 5 OF 6) FIGURE 1: EXTERNAL LAP JOINT INSPECTION LOGIC DIAGRAM**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

4. IN ADDITION, THERE MUST BE NO EVIDENCE OF MISSING FASTENER HEADS, SKIN CRACKS, OR CORROSION COMPLETELY THROUGH THE SKIN AND FOR SECTION 46, THE TEAR STRAPS MUST HAVE BEEN REWORKED BY TEMPORARY REPAIR OR TERMINATING ACTION PER SERVICE BULLETIN 747-53A2279 IN AREA ADJACENT TO CORROSION. CORRECT AS REQUIRED TO MEET THESE CONDITIONS. 5. AS RECOMMENDED BY THE 747 AGING FLEET STRUCTURES WORKING GROUP, ACCOMPLISH THE INSPECTION PROGRAM AND A SELECT PORTION OF THE LAP JOINT MODIFICATION THAT ADDRESSES LAP JOINTS FASTENED WITH DEEP COUNTERSINK RIVETS PER THIS SERVICE BULLETIN PRIOR TO, OR UPON THE ACCUMULATION OF 20,000 FLIGHT CYCLES OR WITHIN 1000 FLIGHT CYCLES AFTER RECEIPT OF REVISION 1 OF THIS SERVICE BULLETIN, WHICHEVER IS LATER. 6. DO NOT USE 747 STRUCTURAL REPAIR MANUAL SUBJECT 53-30-03 FIGURE 18 OR 27 WHEN ACCOMPLISHING A LAP JOINT REPAIR.



### DISTRESSED FASTENER EXAMPLES DISHING OF FASTENER HEAD

EXCESSIVE COUNTERSUNK DEPTH

CRACKS AT FASTENER SHANK1370348



### PILLOWING EXAMPLES INBD 4.50 MIN

INNER SKIN AT JOINT STRAIGHT EDGE OUTER SKIN AT JOINT

SKIN PILLOWING DIMENSION (PILLOWING SHOWN EXAGGERATED FOR CLARITY)1370351

**(SHEET 6 OF 6) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**



### ENTRY DOOR NO. 1 A A

INDICATES AREA OF VISUAL AND HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTIONS.
SECTION 41 LEFT SIDE S-19
S-23 S-14 S-0 STA 520

STA 287 STA 260 STA 220 STA 180 STA 140 STA 340 STA 400

1 2 3

1 21370356

**(SHEET 1 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

UP
INBD TYPICAL LAP JOINT SECTION 41 STRINGER TYPICAL SECTION 42, 44 AND 46 STRINGER TYPICAL

INNER SKIN OUTER SKIN



### SECTION A-A 3 1 21370362

**(SHEET 2 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

ENTRY DOOR NO. 1 A A

INDICATES AREA OF VISUAL AND HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTIONS.
SECTION 41 LEFT SIDE CREW DOOR

S-19
S-23 S-14 S-0 STA 520

STA 287 STA 260 STA 220 STA 180 STA 140 STA 340 STA 400

1 2 3

1 21370395

**(SHEET 3 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

S-23 S-19 S-12 S-6
S-0

S-23 S-19 S-12 S-6 S-0 WING BODY FAIRINGS ENTRY DOOR NO. 2

FORWARD

CARGO DOOR



### RIGHT SIDE SECTION 42

LEFT SIDE SECTION 42 STA 520 STA 941 STA 1000

STA 520 STA 1000 STA 741 WING BODY FAIRINGS ENTRY DOOR NO. 2 A A

INDICATES AREA OF VISUAL AND HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTIONS. 1 2 3

1 21370402

**(SHEET 4 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

S-23 S-19

S-12

S-4 ENTRY DOOR NO. 3

S-23 S-19 S-12 S-4 BL-0

STA 1000 STA 1241 STA 1480
ENTRY DOOR NO. 3 A A



### SECTION 44

APPLICABLE TO RA001-RA014, RA102, RA103 AND RA201 ONLY. AIRPLANES NOT LISTED HAVE FAY-SEALED LAP JOINTS AND DO NOT REQUIRE INSPECTION IN THESE AREAS. INDICATES AREA OF VISUAL INSPECTION ONLY. 1

1

1 

### 1 2

FWD

11370444

**(SHEET 5 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

A A



### SECTION 46 AFT CARGO DOOR



### STA 1961.1 STA 1480 STA 1741.1 ENTRY DOOR NO. 4

S-23 S-19
S-12
S-4

S-4
S-12
S-19 S-23

ENTRY DOOR NO. 4

WING/BODY FAIRINGS WING/BODY FAIRINGS

SEE FIGURE 6 FOR AIRPLANES WITH MAIN DECK SIDE CARGO DOOR.

INDICATES AREA OF VISUAL AND HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTIONS. 1 2 3

1 21370885

**(SHEET 6 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

A A



### SECTION 46 INDICATES AREA OF VISUAL AND HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTIONS. S-23 S-19
S-12

S-4

S-4

S-12
S-19 S-23 BL-0 ENTRY DOOR NO. 5

ENTRY DOOR NO. 5 STA 1961.1 STA 2181.1 STA 2360 BULK CARGO DOOR

1 2 1 2 31370886

**(SHEET 7 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

INITIAL PLANNING REFERENCE CHART **AREA OF INITIAL INSPECTION - VISUAL ONLY 1000 F/C THRESHOLD - REPEAT 1000 F/C INTERVALS**  **STR BODY STATION AREA** 0 Sta 287 to Sta 941 4 L & R Sta 1480 to Sta 2360 6 L & R Sta 520 to Sta 1000 12 L & R Sta 520 to Sta 1000 - Sta 1480 to Sta 2360 14 L & R Sta 140 to Sta 520 19 L & R Sta 140 to Sta 1000 - Sta 1480 to Sta 2360 23 L & R Sta 140 to Sta 1000 - Sta 1480 to Sta 2360
**AREA OF INITIAL INSPECTION - VISUAL ONLY 1000 F/C THRESHOLD - REPEAT 2000 F/C INTERVALS HFEC**  **STR BODY STATION AREA** 4 L & R Sta 1000 to Sta 1480 See F/N 1 12 L & R Sta 1000 to Sta 1480 19 L & R Sta 1000 to Sta 1480 23 L & R Sta 1000 to Sta 1480
**AREA OF INITIAL INSPECTION - VISUAL AND HFEC 1000 F/C THRESHOLD - REPEAT 2000 F/C INTERVALS VISUAL AND**  **4000 F/C INTERVALS HFEC STR BODY STATION AREA**  0 Sta 287 to Sta 941 6 L & R Sta 520 to Sta 1000 12 L & R Sta 520 to Sta 1000 14 L & R Sta 140 to Sta 520 19 L & R Sta 140 to Sta 1000 23 L & R Sta 140 to Sta 1000
**AREA OF INITIAL INSPECTION - VISUAL AND HFEC 1000 F/C THRESHOLD - REPEAT 2000 F/C INTERVALS VISUAL AND**  **6000 F/C INTERVALS HFEC STR BODY STATION AREA**  4 L & R Sta 1480 to Sta 2360 12 L & R Sta 1480 to Sta 2360 19 L & R Sta 1480 to Sta 2360 23 L & R Sta 1480 to Sta 2360

**(SHEET 8 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

The instruction numbers shown below agree with the numbers shown inside the circle symbols in FIGURE 2. 1. Perform an external detailed inspection to determine if corrosion or cracking exists at cold bonded longitudinal body skin lap joints. If evidence of corrosion or cracking is detected during the visual inspection, conduct a high frequency eddy current (HFEC) inspection (Ref. 747 Non-Destructive Test Manual D6- 7170, Part 6, Subject 53-30-02, 53-30-03, 53-30-05) for cracks in the skin at the upper row of fasteners in the lap joint over the entire length of the corroded or cracked skin panel.
**NOTE:** 1. In lieu of visual inspection, non destructive test method for corrosion detection per 747 NonDestructive Manual D6-7170, Part 6, Subject 51-00-00, Figure 5 or Figure 12 may be used. 2. Externally, evidence of corrosion includes skin pillowing or bulges between fasteners; white powder protruding from the lap joint; loose, missing or distressed fastener heads; skin cracks; or corrosion through the skin. 3. Skin pillowing in excess of 0.010 inch is considered evidence of corrosion. As an alternative to measuring pillowing of skin and visual inspection for distressed fasteners, eddy current inspect (Ref. 747 Boeing Non-Destructive Test Manual D6-7170, Part 6, Subject 51-00-00, Figure 5 or Figure 12) to measure the extent of material loss in the lap joint. 2. Perform a high frequency eddy current (HFEC) inspection (Ref. 747 Non-Destructive Manual D6-7170, Part 6, Subject 53-30-02, 53-30-03, 53-30-05) to determine if cracking exists in the outer skin of the lap splice at the upper fastener row (leftmost row at the Stringer 0 lap joint). Repair any cracking found per 747 Structural Repair Manual Subject 53-30-03 prior to further pressurized flight. 3. Perform the following applicable actions:
**NOTE:** 1. Longitudinal lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches will require accomplishment of a structural modification or a second modification, and post modification inspections at the times given in SB 747-53A2463 Revision 1 "FUSELAGE - Skin - Longitudinal Lap Joints Inspection and Repair", Paragraph 1.E., Compliance. 2. Do not use 747 Structural Repair Manual Subject 53-30-03 Figures 18 and 27 when accomplishing a lap joint repair. 3. Figure 7 shows the locations of all lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is less than or equal to 0.071 inches. A. For lap joint areas with cracking or corrosion completely through the skin, repair per 747 Structural Repair Manual Subject 53-30-03 prior to further pressurized flight. B. For missing or distressed fasteners, replace fastener per 747 Structural Repair Manual Subject 53- 30-03, Figure 9 or 10, prior to next pressurized flight, except at deep countersink fastener locations. C. For lap joint areas with skin bulging or pillowing in excess of 0.010 inch, repair per 747 Structural Repair Manual Subject 53-30-03 unless the following three conditions have been met:

**(SHEET 9 OF 10) FIGURE 2: EXTERNAL LAP JOINT CORROSION INSPECTION**  Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

1. Inspection per 747 Non-Destructive Test Manual D6-7170, Part 6, Subject 51-00-00, Figure 5 or Figure 12 indicates that material loss does not exceed 10 percent. 2. No evidence of skin cracks or corrosion completely through the skin is found. 3. For Section 46, tear straps have been reworked by temporary repair or terminating action per Service Bulletin 747-53A2279 in adjacent area.
**NOTE:** Adjacent area refers to the area bounded by the 3 stringer bays above and below the applicable lap joint and the closest tear strap forward and aft of the corroded area. Where corrosion is within 5 inches of a frame, the next distant tear strap from and not the tear strap closest to that frame determines that boundary. D. For lap joint areas where measured material loss does not exceed 10 percent, reinspect per this service bulletin at 500 flight-cycles as specified in the procedure (Method I or II) being used. Terminating action must be performed on corroded lap joint (from forward circumferential splice to aft circumferential splice) within 30 months of being found. E. For lap joint areas where material loss is greater than 10 percent, repair per 747 Structural Repair Manual Subject 53-30-03 prior to next pressurized flight. F. For any lap splice which is required to be repaired per 747 Structural Repair Manual Subject 53-30- 03, terminating action must be performed on the remaining unrepaired length of the skin panel (from forward circumferential splice to aft circumferential splice of repaired skin panel) within 15 months of the repair. If existing repairs are found during the initial visual inspection of this bulletin, terminating action must be accomplished on the remaining unrepaired length of the skin panel within 15 months of being found.
**NOTE:** Terminating action may still require further actions as given in Service Bulletin 747-53A2463. G. Inspect repairs as given in 747-100/200/300 SRM 53-30-03 or as given in the 747 Repair Assessment Guidelines document D6-36181. For any external doubler repairs greater than 40 inches in length (in the horizontal direction) do internal surface HFEC inspections every 3,000 flight-cycles.

**(SHEET 10 OF 10) FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 48 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS**

FLIGHT ENGINEER'S STATION STA 394

STA STA STA STA 332

260

340

520 LAVATORY AREA

PILOTS' STATION

OBSERVERS' STATION
STOWAGE AREA UPPER DECK

TYPICAL FLIGHT DECK INSTALLATION ALL AFFECTED CONFIGURATIONS SIMILAR P5, P7, P12, (AND P126) OVERHEAD PANELS

1 2 3 5

UP FWD1370852

**(SHEET 1 OF 4) FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

FWD UP 6

330 300 STA STA1370856

**(SHEET 2 OF 4) FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 50 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

The instruction numbers shown below agree with the numbers shown inside the circle symbols in Figure 3. 1. Remove the flight engineer's seat per 747 Maintenance Manual Subject 25-11-02 or operator's comparable procedure. Remove the observer's seat per 747 Maintenance Manual Subject 25-11-03 or operator's comparable procedure. Remove the crew seat per 747 Maintenance Manual Subject 25-11- 05 or operator's comparable procedure. 

### UP

FWD 6

390 STA 300 STA1370859

**(SHEET 3 OF 4) FIGURE 3: FLIGHT DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

2. Remove the pilot's seats per 747 Maintenance Manual Subject 25-11-01, or operator's comparable procedure. 3. Remove the pilots' overhead panel P5 and circuit breaker panels P7, P12 (and P126 if installed). Reference 747 Maintenance Manual Subject 31-00-00. 4. Not shown - Cover pedestal, panels, racks, and all wire bundle connectors with plastic sheets to help prevent contamination or damage of equipment. 5. Remove and salvage disconnect panels behind the pilots' overhead panel P5 and circuit breaker panels P7 and P12. Disconnect wire bundles as required to enable disconnect panels to be moved clear of modification area for dripshield removal.
**NOTE:** Prior to disconnecting any wire bundles from disconnect panels, removing any wire bundles from wire bundle clamps or disconnecting any separate ground wires, ensure that all wire bundles and separate wires are identified and suitably marked for reinstallation. 6. Remove and salvage the overhead sidewall linings, moldings, dripshields, and insulation in flight deck area per 747 Maintenance Manual Subject 25-14-01 or operator's comparable procedure. 7. Not shown - Loosen and deflect any installed pitot static tubing as required in modification areas per 747 Maintenance Manual Subject 34-11-00 or operator's comparable procedure. 8. Not shown - Loosen and deflect, or remove any oxygen tubing in modification areas, as required per 747 Maintenance Manual Subject 35-00-00 or operator's comparable procedure. 9. Not shown - Remove crew escape hatch per 747 Maintenance Manual Subject 53-21-01 or operator's comparable procedure.

**(SHEET 4 OF 4) FIGURE 4: UPPER DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 4: UPPER DECK LAP JOINT INTERNAL ACCESS**

The instruction numbers shown below agree with the numbers shown inside the circle symbols in FIGURE 4. 1 AFT PARTITION FLIGHT COMPARTMENT
FLIGHT COMPARTMENT DOOR E11 RACK ENCLOSURE PARTITION RIGHT CREW DOOR

LEFT CREW DOOR (IF INSTALLED) FLOOR MOUNTED ESCAPE SLIDE (TYPICAL) FORWARD LEFT PARTITION

CENTER LIGHTED REVEAL UPPER CLOSURE PANEL TYPICAL UPPER DECK CONFIGURATION WITH LEFT AND RIGHT CREW DOOR (OTHER UPPER DECK CONFIGURATIONS SIMILAR)

WINDOW REVEAL PSU PANEL LOWER CLOSURE PANEL

STOWAGE BIN1370861

**(SHEET 1 OF 2) FIGURE 4: UPPER DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

1. Remove and salvage equipment and furnishings as required to gain access to STA 420 through STA 520 lap joints. Refer to the following maintenance manual subjects for removal procedure.

2. Not shown - Install all items which are removed in the preceding step per the applicable maintenance manual subject or operator's comparable procedure. **Equipment Maintenance Manual Subject**  Window Reveal 25-21-02 Sidewall and Ceiling Insulation 25-21-04 Ceiling Panels 25-22-03 Passenger Service Units 25-23-01 Forward Closets 25-24-00 Forward Right Partition 25-24-11 Forward Left Partition 25-24-12 Crew Rest Area 25-24-19 Passenger Seats 25-25-01 Wall Mounted Attendant Seat 25-25-04 Stairway Forward Right Partition 25-26-02 Stair Aft Right Partition 25-26-03 Stairway Forward Left Partition 25-26-06 Sidewall Stowage Units 25-28-15 Overhead Stowage Bins 25-28-23 Lavatories 25-40-03 Floor Mounted Escape Slide 25-68-02 Crew Entry Door 52-13-01 Flight Compartment Door 52-51-01

**(SHEET 2 OF 2) FIGURE 5: MAIN DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 54 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 5: MAIN DECK LAP JOINT INTERNAL ACCESS**

The instruction numbers shown below agree with the numbers shown inside the circle symbols in FIGURE 5. **CAUTION:** TO PREVENT DAMAGE TO FLOOR PANELS, IT IS RECOMMENDED THAT A 1/2 INCH THICK, 1 FOOT SQUARE PLYWOOD BEARING PAD BE USED UNDER EACH LEG OF LADDERS, CEILING ATTENDANT SERVICE

PANEL PANEL

DOOR ONE MAIN ENTRY SERVICE UNIT PASSENGER

PANEL ATTENDANT

LINING PANEL SIDEWALL STOWAGE BIN OVERHEAD

(OTHER MAIN DECK CONFIGURATIONS SIMILAR) TYPICAL MAIN DECK CONFIGURATION 11370864

**(SHEET 1 OF 2) FIGURE 5: MAIN DECK LAP JOINT INTERNAL ACCESS**  December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

STANDS OR SCAFFOLDS. ADDITIONALLY, IT IS ALSO RECOMMENDED THAT ONLY ONE PERSON BE ALLOWED TO USE EACH LADDER, STAND OR SCAFFOLD. 1. Remove and salvage equipment and furnishings as required to gain access to STA 140 through STA 2360 lap joints. Refer to the following maintenance manual subjects for removal procedure.

2. Not shown - Install all items which are removed in the preceding step per the applicable maintenance manual subject or operator's comparable procedure. **Equipment Maintenance Manual Subject**  Sidewall Lining Panels 25-21-01/-02 Sidewall and Ceiling Insulation 25-21-04 Sidewall Dado Panels 25-21-12 Ceiling Panels 25-22-01/-03 Entryway Ceiling Panels 25-22-06 Passenger Service Units 25-23-01 Attendant Service Unit 25-23-04 Forward Closets 25-24-00 Partitions 25-24-05 Passenger Seats 25-25-01 Track Mounted Attendant Seats 25-25-03 Wall Mounted Attendant Seats 25-25-04 Floor Covering 25-27-00 Insulation Blankets 25-28-01 Overhead Stowage Bins 25-28-23 Sidewall Galleys 25-31-04 Sidewall Lavatories 25-40-01 Cargo Lining Panels 25-59-01 Attendant Panel 25-23-05 Oxygen Tubing 35-21-00 Main Entry Door No. 1 52-11-01 Floor Panels 53-21-02

**(SHEET 2 OF 2) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

**FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR LESS** 



### STA 2360 STA 1961.1 STA 1480 STA 1000 STA 520

SEE DETAIL I (PASS) SEE DETAIL V (R6001) SEE DETAIL II

NOTE: SEE DETAIL VII FOR A/P'S WITH MAIN DECK SIDE CARGO DOOR MODIFICATION SEE DETAIL III (PASS) SEE DETAIL VI (R6001) SEE DETAIL IV1370872

**(SHEET 1 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE STA 899 R6001 STA 774 ALL EXCEPT R6001 STA 796.5 ALL EXCEPT R6001 STA 755 R6001 SEC 42 S-12

S-23 S-19 S-6 S-0 S-19 S-23 S-14 S-0

RIGHT SIDE OPPOSITE (EXCEPT CREW DOOR) LEFT SIDE SHOWN



### DETAIL II DETAIL I

STA 520 1000

STA 941 STA 941 1 STA 287 STA 520

STA 1

21370868

**(SHEET 2 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE STA 1716 SEC 46

FWD

SEC 46 AFT S-23 S-19 S-12 S-4 S-23 S-19 S-12 S-4



### DETAIL IV LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE ALL EXCEPT R6001 SEE DETAIL VI 

### DETAIL III

STA 1961 2360 STA

1 1
1741 STA
STA 1638 1572 STA STA

STA 1480 1961

1484 STA 11370874

**(SHEET 3 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

1485 STA 1961 STA

STA 1480

STA 1538

STA 1642 STA 1642 STA 1737 STA 1741

SEC 46

FWD R6001

LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE SEC 41 R6001 STA 1572 S-12 S-4

S-19
S-23 S-0

S-14

S-19 S-23 STA 520 STA

287

1



### DETAIL VI LEFT SIDE SHOWN RIGHT SIDE OPPOSITE (EXCEPT CREW DOOR) 

### DETAIL V 11370879

**(SHEET 4 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 60 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

STA 1480 STA 1572 STA 1700 STA 1735 STA 1960 STA 2000 STA 1965
S-4

S-12

S-19

S-23

STA 1638 STA 1716 STA 1485

6 3 4 5 1

4 5



### DETAIL VII1370880

**(SHEET 5 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 61 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

Station locations shown in table represent areas of lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is 0.090 or less. Airplanes are presented in three groups to separate the passenger configuration from the freighter configuration and distinct lap joint inspection and terminating action requirements. Airplanes with the Main Deck Side Cargo Door (MDSCD) modification will find lap joint information for that area in Detail VII.
**SECTION 41 STR AREA GROUP AREA GROUP**  Str 0 Sta. 287 to Sta. 520 1,2,3 Str 14 L Sta. 134.4 to Sta. 520 1,2 Sta. 134.4 to C2 C3 to Sta. 520 3 R Sta. 134.4 to Sta. 520 1,2 Sta. 134.4 to C2 C3 to Sta. 520 3 Str 19 L Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3 R Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta.400 3 Str 23 L Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3 R Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3

**SECTION 42 STR AREA GROUP AREA GROUP**  Str 0 Sta. 520 to Sta. 941 1,2,3 Str 6 L Sta. 520 to Sta. 941 1,2,3 R Sta. 520 to Sta. 941 1,2,3 Str 12 L Sta. 520 to Sta. 1000 1,2,3 R Sta. 520 to Sta. 1000 1,2,3 Str 19 L Sta. 520 to Sta. 741.1 1,2,3 L Sta. 741.1 to Sta. 772 1,2 Sta. 741.1 to Sta. 899 3 R Sta. 520 to Sta. 741.1 1,2,3 R Sta. 741.1 to Sta. 772 1,2, Sta. 741.1 to Sta. 899 3 Str 23 L Sta. 520 to Sta. 796.5 1,2 Sta. 520 to Sta. 755 3 R Sta. 520 to Sta. 796.5 1,2 Sta. 520 to Sta. 755 3
**SECTION 46 STR AREA GROUP AREA GROUP**  Str 4 L Sta. 1572 to Sta. 2360 1,2,3 R Sta. 1572 to Sta. 2360 1,2,3 Str 12 L Sta. 1484 to Sta. 2360 1,2,3 R Sta. 1484 to Sta. 2360 1,2,3

**(SHEET 6 OF 7) FIGURE 6: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.090 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 62 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

The instruction numbers shown below agree with the numbers shown inside the circle symbols in the figure. 1. Illustrations show highlighted areas where the upper (overlapping) skin thickness is 0.090 or less. Where the upper (overlapping) skin thickness at upper fastener row tapers longitudinally and changes between body frames from more than 0.090 inches thickness to less than 0.090 inches thickness, the start of protruding head fasteners is indicated at a specific body frame, even though the skin may be thicker than 0.090 at the start. Refer to Table I. 2. The skin configuration of the upper (overlapping) skin in this area is a doubler hot bonded to the skin. This area is fastened with deep countersink rivets. 3. The skin panel joints at Str 4 between Sta 1741 and Sta 1961 and Str 12 between Sta 1741 and the forward side of the door, and between the aft side of the door and Sta 1961 are butt joints and require no inspection or modification. 4. These areas require inspection. Refer to 747 Non Destructive Test Manual D6-7170, Part 6, Subject 53- 30-09. 5. The straps and doublers at Str 4, Sta 1700 to Sta 2000, and Str 12, Sta 1735 to forward side of door, and from the aft side of door to Sta 1965 need to be removed to accomplish full modification of the lap joints forward of Sta 1741 and aft of Sta 1961. Reinstallation of the straps and doublers will require a special kit of oversize fasteners. 6. No inspection of this area is necessary. The MDSCD modification accomplished terminating action per this service bulletin in this area. Str 19 L Sta. 1480 to Sta. 1638 Sta. 1741 to Sta. 2360 1,2 Sta. 1480 to Sta. 1538 Sta. 1642 to Sta.1737.6 Sta. 1741 to Sta. 2360 3

R Sta. 1480 to Sta. 1638 Sta. 1741 to Sta. 2360 1,2 Sta. 1480 to Sta. 1538 Sta. 1642 to Sta.1737.6 Sta. 1741 to Sta. 2360 3

Str 23 L Sta. 1480 to Sta 1716.5 Sta. 1741 to Sta. 2360 1,2 Sta. 1642 to Sta.2360 3
R Sta. 1480 to Sta 1716.5 Sta. 1741 to Sta. 2360 1,2 Sta. 1642 to Sta.2360 3 **SECTION 46 STR AREA GROUP AREA GROUP** 

**(SHEET 7 OF 7) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 63 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

**FIGURE 7: LOCATIONS OF LAP JOINT UPPER (O VERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS**

SEE DETAIL III (PASS) SEE DETAIL I (PASS) SEE DETAIL V (R6001) SEE DETAIL II SEE DETAIL IV STA 1480 STA 2360 STA 1961.1 STA 1000 STA 520

NOTE: SEE DETAIL VI FOR A/P'S WITH MAIN DECK SIDE CARGO DOOR MODIFICATION1370873

**(SHEET 1 OF 6) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 64 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

881 STA S-12

S-23 S-19 S-6 S-0 S-19 S-23 S-14 S-0

RIGHT SIDE OPPOSITE (EXCEPT CREW DOOR) LEFT SIDE SHOWN



### DETAIL II 763 STA STA 741 

### DETAIL I

STA 520 1000

STA 941 STA 941 1 STA 287 STA 520

STA 11370882

**(SHEET 2 OF 6) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 65 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

ALL S-23 S-19 S-12 S-4 S-23 S-19 S-12 S-4



### DETAIL IV DETAIL III

STA 1961

STA 2181 2360 STA

1 1
1741 STA
STA 1622.5 STA

STA 1480 1961 STA 1572 STA 1738.2 STA 1741

STA 1489.5 STA 1737.8

PASS ONLY1370883

**(SHEET 3 OF 6) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 66 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

1489.5

STA

1622.5 STA STA 1780 STA 1700 1961 STA

STA 1480

STA 1735

STA 1920 STA 1572 S-12 S-4

S-19
S-23 S-0

S-14

S-19 S-23 STA 520 STA

287

1



### DETAIL VI DETAIL V 11370884

**(SHEET 4 OF 6) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 67 of 68 

### BOEING SERVICE BU **LLETIN 747-53-2307**

This figure will assist the operator in identifying lap joint areas for the After Modification Inspection. All lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 or less must have the After Modification Inspection. Station locations shown in table represent areas of lap joints where the upper (overlapping) skin thickness at the upper row of fasteners is 0.071 or less. Airplanes are presented in three groups to separate the passenger configuration from the freighter configuration.
**SECTION 41 STR AREA GROUP AREA GROUP**  Str 0 Sta. 287 to Sta. 520 1,2,3 Str 14 L Sta. 134.4 to Sta. 520 1,2 Sta. 134.4 to C2 C3 to Sta. 520 3 R Sta. 134.4 to Sta. 520 1,2 Sta. 134.4 to C2 C3 to Sta. 520 3 Str 19 L Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3 R Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3 Str 23 L Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3 R Sta. 134.4 to Sta. 400 1,2 Sta. 134.4 to C2 C3 to Sta. 400 3

**SECTION 42 STR AREA GROUP AREA GROUP**  Str 0 Sta. 520 to STA. 941.1 1,2,3 Str 6 L Sta. 520 to STA. 941.1 1,2,3 R Sta. 520 to STA. 941.1 1,2,3 Str 12 L Sta. 520 to STA. 881.1 1,2,3 R Sta. 520 to STA. 881.1 1,2,3 Str 19 L Sta. 520 to Sta 763.07 1,2 Sta. 520 to Sta. 741.1 3 R Sta. 520 to Sta 763.07 1,2 Sta. 520 to Sta. 741.1 3 Str 23 L Sta. 520 to Sta. 741.1 1,2,3 R Sta. 520 to Sta. 741.1 1,2,3
**SECTION 46 STR AREA GROUP AREA GROUP**  Str 4 L Sta. 1572 to Sta. 1738.2 Sta. 1741.1 to Sta. 2360 1,2,3
R Sta. 1572 to Sta. 1738.2 Sta. 1741.1 to Sta. 2360 1,2,3
Str 12 L Sta. 1489.5 to Sta. 1737.8 Sta. 1741.1 to Sta. 2360 1,2,3
R Sta. 1489.5 to Sta. 1737.8 Sta. 1741.1 to Sta. 2360 1,2,3

**(SHEET 5 OF 6) FIGURE 7: LOCATIONS OF LAP JOINT UPPER (OVERLAPPING) SKIN THICKNESS 0.071 INCHES OR**  **LESS** Original Issue: December 21, 1989 Revision 3: April 16, 2009 747-53-2307 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 68 of 68 

### BOEING SERVICE BULLETIN 747-53-2307

The instruction number shown below agree with the number shown inside the circle symbol in the figure. 1. Illustrations show highlighted areas where the upper (overlapping) skin thickness is 0.071 or less. Where the upper (overlapping) skin thickness at upper fastener row tapers longitudinally and changes between body frames from more than 0.071 inches thickness to less than 0.071 inches thickness, the start of protruding head fasteners is indicated at a specific body frame, even though the skin may be thicker than 0.071 at the start. Refer to Table I. Str 19 L Sta. 1480 to Sta. 1622.5 Sta. 1741.1 to Sta. 2360 1,2 Sta. 1741.1 to Sta. 2360 3
R Sta. 1480 to Sta. 1622.5 Sta. 1741.1 to Sta. 2360 1,2 Sta. 1741.1 to Sta. 2360 3 Str 23 L Sta. 1961.1 to Sta.2360 1,2 Sta. 2181.1 to Sta. 2360 3 R Sta. 1961.1 to Sta.2360 1,2 Sta. 2181.1 to Sta. 2360 3 **SECTION 46 STR AREA GROUP AREA GROUP** 

**(SHEET 6 OF 6)**