### Commercial **Airplanes** 

# 747 Service Bulletin **Number: 747-53A2465** Original Issue: April 05, 2001 Revision 5: July 11, 2013 ATA System: 5311 **SUBJECT:** FUSELAGE - Main Frame - Nose Wheel Well Side Panel and Top Panel - Web and Stiffener Inspection Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2001 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 1 of 51 4.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 2 of 51 **BOEING SERVICE BULLETIN 747-53A2465**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 27 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 29 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 29 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 FIGURE 1: INSPECTION OF AREA 1 - ALL AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . 35 FIGURE 2: INSPECTION OF AREA 2 [Group 1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 FIGURE 3: INSPECTION OF AREA 2 [Group 2]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 FIGURE 4: INSPECTION OF AREA 3 - ALL AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . 45 FIGURE 5: SECONDARY INSPECTION OF SIDE PANEL VERTICAL BEAMS AND HORIZONTAL STIFFENERS - ALL AIRPLANES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 FIGURE 6: SECONDARY INSPECTION OF LONGITUDINAL STIFFENERS, FLOOR BEAM LOWER CHORDS, FLOOR BEAM WEBS, AND VERTICAL BEAM UPPER ENDS [Group 1] . . . 50

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 3 of 51 **BOEING SERVICE BULLETIN 747-53A2465**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 4 of 51 **BOEING SERVICE BULLETIN 747-53A2465**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **Revision Transmittal Sheet Number: 747-53A2465**  Original Issue: April 05, 2001 Revision 5: July 11, 2013 ATA System: 5311 **SUBJECT:** FUSELAGE - Main Frame - Nose Wheel Well Side Panel and Top Panel - Web and Stiffener Inspection This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** More work is necessary on the airplanes inspected in accordance with the original issue or Revision 1 of this service bulletin. Revision 2 changed inspection requirements and compliance times. More work may be necessary on the airplanes inspected in accordance with the Revision 2 of this service bulletin. Revision 3 changed the initial compliance threshold for airplanes with 19,000 or more total flight cycles. More work may be necessary on the airplanes inspected in accordance with the Revision 3 of this service bulletin. Revision 4 changed the inspection methods and repeat inspection intervals for airplanes with 20,000 flight cycles or more. No more work is necessary on airplanes inspected in accordance with the Revision 4 of this service bulletin. However, this revision reduces the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web. Federal Aviation Administration (FAA) Airworthiness Directive AD 2006-22-15 is related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the revised compliance tasks and times given in this service bulletin mandatory. **REASON FOR REVISION** This revision is sent to reduce the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web, and to clarify inspection requirements in Figures 1, 2, and 3. These sections were changed: 1. In Summary: Added service history information since Revision 4. Added reference to Service Related Problem 747-SRP-53-0408 and related Fleet Team Digest articles. Also, added Planning Data table and reference to AD 2006-22-15. 2. In paragraph 1.C., Reason: Added service history information since Revision 4. Added reference to Service Related Problem 747-SRP-53-0408 and related Fleet Team Digest articles. 3. In paragraph 1.D., Description: Added "no more work" statement for Revision 5.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 5 of 514. In paragraph 1.E., Compliance: Tables identified as "Table 1" and "Table 2" in previous revisions of this service bulletin have been re-identified as "Table 2" and "Table 3", respectively. A new Table identified as "Table 1" has been added for inspection of the nose wheel well sidewall panel webs and top panel web at a reduced initial inspection threshold. Also, added reference to related AD 2006-22-15, and revised compliance Table 2 and Table 3 to reflect the compliance times specified in AD 2006-22-15. 5. In paragraph 1.F., Approval: Updated approval statement and added Alternative Method of Compliance statement for AD 2006-22-15. 6. In paragraph 1.K., Publications Affected: Added damage tolerance inspection statement. 7. In paragraph 3.A., General Information: Updated general notes. 8. In paragraph 3.B., Work Instructions: Updated SRM references. 9. In Figure 1: Added sentence to footnote (b) related to UT inspection information, that was previously in footnote (a). Figure 1 inspection requirements have not changed. 10. In Figure 2: Added cross sections B-B and C-C. Clarified side panel web detailed inspection. 11. In Figure 3: Added cross section B-B, and clarified side panel web detailed inspection. 12. In Figure 4: Added footnotes (a), (b), (c), and (d) to clarify inspection requirements. 13. Throughout the service bulletin, the words "as shown in" or "shown in" have been changed to "as given in" or "given in" when referring to procedures or bulletin sections that must be used. The words "as shown in" have been changed to "refer to" when referring to maintenance manual procedures. Vertical lines have not been put on the left edge of the pages where these changes were made. 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** April 05, 2001 Original Issue: October 16, 2003 Revision 1: November 11, 2004 Revision 2: December 23, 2004 Revision 3: February 24, 2005 Revision 4: July 11, 2013 Revision 5:

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 6 of 51 **BOEING SERVICE BULLETIN 747-53A2465**

### Commercial **Airplanes** 

# 747 Service Bulletin **Summary Number: 747-53A2465**  Original Issue: April 05, 2001 Revision 5: July 11, 2013 ATA System: 5311 **SUBJECT:** FUSELAGE - Main Frame - Nose Wheel Well Side Panel and Top Panel - Web and Stiffener Inspection **CONCURRENT REQUIREMENTS** None **BACKGROUND** Accomplishment of the inspections shown in this service bulletin will ensure the structural integrity of the nose wheel well top panel and side panels. Cracks in the top panel or side panel webs and stiffeners that are not found and repaired could become large and cause in flight depressurization and loss of structural integrity. Three operators have told Boeing about nose wheel well side panel web cracks that were found on four airplanes with 15,900 - 32,018 flight cycles. The cracks that were found were 1.5 inch to 14.5 inch long. In addition, a 17.5 inch long crack was found in the side panel web on Boeing's 747-400 Fatigue Test airplane at 58,890 pressure cycles. One operator has also reported a 13 inch long nose wheel well top panel web crack on one airplane. This airplane had flown 15,726 total flight cycles. Two operators have also reported nose wheel well side panel horizontal stiffener cracks on two airplanes. On one airplane with 19,577 flight cycles, a 12 inch long stiffener crack was found. On the other airplane with 31,863 flight cycles, 9 inch and 13 inch long stiffener cracks were found. Revision 2: After the initial release of this service bulletin, two operators have told Boeing that large sidewall panel web cracks (up to 12 inches long) were found during visual inspection on two airplanes. On one airplane, a 12 inch long side panel crack was found 1,178 flight cycles after the ultrasonic inspections shown in the initial release and Revision 1 of this service bulletin was accomplished. On the other airplane, multiple side panel cracks (up to 8.8 inches long) were found approximately 3,500 flight cycles after the ultrasonic inspection was accomplished. Revision 3: After Revision 2 of this service bulletin, an operator reported an in flight decompression of an airplane with 27,241 flight cycles. Upon inspection, the nose wheel well right hand side panel web was torn open between STA 260 and STA 280, and from WL 160 to WL 170. The airplane landed safely, however, the decompression resulted in deployment of the oxygen masks and a decision by the crew to conduct an air turn back. In addition, the decompression caused damage to the Nose Landing Gear doors and adjacent structure. Since Revision 4 of this service bulletin, Boeing has received six additional reports of cracks in the nose wheel well side panels and/or side panel stiffeners. Two of the reports were on airplanes with 17,320 and 21,623 flight cycles. The other four reports were on airplanes with between 13,541 and 13,828 flight cycles.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 7 of 51Boeing has determined that all the reported nose wheel well cracks were caused by fatigue. Furthermore, the nose wheel well top and side panels have been determined to be structure that could develop Widespread Fatigue Damage (WFD). For more information about WFD, refer to 747-SL-53-088. Service history and Boeing analysis show that fatigue cracking in the NWW top and side panels before 16,000 total flight cycles will be confined to a single bay between web stiffeners. Boeing has determined that cracking in a single stiffener bay is not an airplane safety concern. However, beyond 16,000 total flight cycles, WFD could result in cracking across multiple stiffener bays and a depressurization event significant enough to affect the structural integrity of the fuselage. In order to detect and repair possible cracking, and prevent a possible depressurization event, Boeing recommends that operators accomplish the inspections given in this service bulletin. Due to the possibility that the Federal Aviation Administration (FAA) will issue a new Airworthiness Directive to address cracking before 16,000 total flight cycles, the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web is being reduced to 13,000 total flight cycles. Boeing Structural Item Interim Advisory SIIA 747-129 is related to this service bulletin. Boeing Service Related Problems (SRP) 747-SRP-53-0133, 747-SRP-53-0231, and 747-SRP-53-0408 are related to this service bulletin. Boeing Fleet Team Digest (FTD) articles 747 FTD 53-12006 and 747 FTD 53-04002 are related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information.
**Reference Affected**  **Planning Data** Paragraph 1.A.2., Spares Affected No Spares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval Yes AD Related Paragraph 1.H., Weight and Balance Changes No Weight and Balance Change Paragraph 1.I., Electrical Load Data No Electrical Load Changed Paragraph 1.K., Publications Affected No Publications Affected Paragraph 1.K., Publications Affected No Airplane Flight Operations Affected (Flight CrewOperations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/Parts No Kits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator No Operator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin No Special Tooling Required

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 8 of 51 **BOEING SERVICE BULLETIN 747-53A2465 ACTION**  AREA 1 - Sidewall Panel Web at WL 150, WL 160, and WL 170: Open the Nose Landing Gear doors. Do a detailed inspection (and a UT inspection, if over 20,000 total flight cycles) of the Nose Wheel Well side panel for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Repair web cracks as given in the Structural Repair Manual or ask Boeing for repair data. AREA 2 - Sidewall Panel Web at WL 140 and WL 180 and Top Panel Web: Open the Nose Landing Gear doors. Do a detailed inspection (and a UT inspection, if over 20,000 total flight cycles) of the Nose Wheel Well side panel and top panel webs for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Repair web cracks as given in the Structural Repair Manual or ask Boeing for repair data. AREA 3 - Sidewall Panel and Top Panel Stiffeners: Get internal access to the Nose Wheel Well side panels and top panel. Do detailed and surface High Frequency Eddy Current (HFEC) inspections of the longitudinal stiffeners for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Replace cracked stiffeners, or ask Boeing for repair data. Do the AREA 1, AREA 2, and AREA 3 inspections again at the times given in this service bulletin. **EFFECTIVITY** All 747-100/-100B/-100B SUD/-200B/-200C/-200F/-300/-400/-400D/-400F/-SP/-SR airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** Federal Aviation Administration (FAA) Airworthiness Directive AD 2006-22-15 is related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the revised compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection and repair procedures given in this service bulletin. **MANPOWER Elapsed Time (Hours)**  **Total Man-Hours Airplanes**  13.5 27 All Airplanes - Area 1 10 20 Group 1 - Area 2 5 10 Group 2 - Area 2 36 72 All Airplanes - Area 3

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 9 of 51 **BOEING SERVICE BULLETIN 747-53A2465 MATERIAL INFORMATION**  None

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 10 of 51 **BOEING SERVICE BULLETIN 747-53A2465**

### Commercial **Airplanes** 

# 747 Service Bulletin **Number: 747-53A2465** Original Issue: April 05, 2001 Revision 5: July 11, 2013 ATA System: 5311 **SUBJECT:** FUSELAGE - Main Frame - Nose Wheel Well Side Panel and Top Panel - Web and Stiffener Inspection **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplane(s) shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 747 airplanes, line numbers 1 - 1419, except 747-200C, 747-200F, and 747-400F airplanes. - 1
All 747-200C, 747-200F, and 747-400F airplanes.

- 2

Airplane Models: 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, 747SR **Group Variable Number**  1 RA001 - RA034 1 RA101 - RA115 1 RA161 - RA164 1 RA201 - RA203 1 RA216 - RA217 1 RA245 - RA246 1 RA251 - RA266 1 RA301 - RA318

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 11 of 51**Group Variable Number**  1 RA351 - RA360 1 RA369 - RA373 1 RA401 - RA418 1 RA501 - RA502 1 RA521 - RA528 1 RA532 - RA548 1 RA551 - RA552 1 RA559 - RA561 1 RA581 - RA582 1 RA585 1 RA601 - RA602 1 RA631 - RA635 1 RA651 - RA652 1 RA671 - RA677 1 RA701 - RA702 1 RA721 - RA731 1 RA741 - RA745 1 RA749 - RA750 1 RA761 - RA762 1 RA781 - RA784 1 RA901 - RA916 1 RB001 - RB016 1 RB041 - RB044 1 RB071 - RB075 1 RB101 - RB102 1 RB411 - RB413 1 RB421 1 RB601 - RB607 1 RB681 - RB697 1 RB711 1 RB721 - RB723 1 RB741 - RB748 1 RD001 - RD004

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 12 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RD021 - RD022 1 RD041 - RD059 1 RD071 - RD072 1 RD081 - RD083 1 RD091 - RD092 1 RD101 - RD104 1 RD121 - RD127 1 RD131 - RD144 1 RD166 - RD167 1 RD171 - RD172 1 RD181 - RD183 1 RD201 - RD204 1 RD221 - RD227 1 RD231 - RD235 1 RD241 - RD243 1 RD251 - RD262 1 RD271 - RD272 1 RD291 - RD292 1 RD301 - RD302 1 RD311 1 RD351 - RD358 1 RD361 - RD366 1 RD381 - RD383 1 RD411 - RD414 1 RD421 - RD426 1 RD431 - RD435 1 RD441 - RD442 1 RD451 - RD456 1 RD461 1 RD471 - RD475 1 RD513 - RD519 1 RD531 - RD533 1 RD551

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 13 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RD561 1 RD571 1 RD581 - RD583 1 RD591 - RD593 1 RD601 - RD607 1 RD621 - RD623 1 RD641 - RD649 1 RD651 - RD659 1 RD661 1 RD671 1 RD681 - RD682 1 RD691 - RD692 1 RD701 - RD702 1 RD721 - RD722 1 RD741 - RD742 1 RD751 - RD755 1 RD761 1 RD771 - RD775 1 RD781 - RD783 1 RD791 - RD792 1 RE001 1 RF001 - RF006 1 RG001 - RG009 1 RG091 1 RG095 1 RG101 - RG104 1 RG121 - RG126 1 RG141 - RG142 1 RG161 - RG164 1 RG171 - RG174 1 RG191 - RG193 1 RG211 - RG213 1 RG221 - RG222

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 14 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RH101 - RH102 1 RH111 - RH112 1 RH121 - RH122 2 RJ131 - RJ133 2 RJ151 - RJ152 2 RJ301 - RJ303 2 RJ321 - RJ322 2 RJ331 - RJ333 2 RL401 - RL403 2 RL411 - RL436 2 RL451 - RL456 2 RL461 - RL462 2 RL471 - RL481 2 RL491 - RL492 2 RL501 - RL502 2 RL511 - RL516 2 RL521 - RL522 2 RL531 - RL534 2 RL551 2 RL561 - RL568 2 RL571 - RL572 2 RL576 - RL577 2 RL579 2 RL581 - RL586 2 RL651 - RL655 2 RL671 - RL675 2 RL681 - RL684 2 RL751 - RL752 1 RM001 - RM007 1 RM010 - RM013 1 RM021 - RM024 1 RM026 - RM030 1 RM036 - RM045

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 15 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RM051 - RM053 1 RM071 1 RM081 - RM084 1 RM091 1 RM096 - RM097 1 RM116 - RM117 1 RM126 - RM132 1 RM136 - RM147 1 RM156 - RM158 1 RM166 - RM177 1 RM191 - RM192 1 RM231 - RM233 1 RM241 - RM246 1 RM261 - RM264 1 RM316 - RM318 1 RM331 - RM333 1 RM341 1 RM351 - RM355 1 RM366 - RM367 1 RM401 - RM403 1 RM426 1 RM431 1 RM441 - RM443 1 RM445 1 RM801 - RM803 1 RM811 - RM813 2 RM851 - RM859 2 RM861 - RM863 2 RM871 - RM899 2 RM901 - RM906 2 RM911 2 RR001 - RR005 2 RR021 - RR025

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 16 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 2 RR031 2 RR201 - RR206 2 RR221 - RR226 2 RR261 - RR267 2 RR301 - RR310 2 RR331 - RR332 2 RR336 2 RR341 - RR345 2 RR361 - RR362 2 RR421 - RR422 2 RR431 - RR432 2 RR441 - RR442 2 RR451 2 RR501 - RR504 2 RR521 - RR522 2 RR526 2 RR531 2 RR551 - RR556 2 RR561 2 RR566 2 RR701 2 RR721 - RR724 2 RR746 - RR748 2 RR851 - RR856 2 RR861 - RR862 2 RR951 - RR952 1 RS001 - RS002 1 RS201 1 RS211 - RS212 1 RS221 - RS222 1 RS231 - RS241 1 RS251 - RS259 1 RS263

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 17 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RS265 - RS268 1 RS271 - RS276 1 RS291 - RS292 1 RS301 - RS306 1 RS311 - RS320 1 RS331 - RS333 1 RS341 - RS342 1 RS699 1 RS701 - RS703 1 RS711 - RS713 1 RS721 - RS722 1 RS731 - RS732 1 RS741 - RS743 1 RS751 - RS752 1 RS761 - RS762 1 RS771 1 RS781 - RS782 1 RS786 1 RT001 - RT014 1 RT021 - RT022 1 RT031 - RT035 1 RT041 - RT047 1 RT061 1 RT071 - RT075 1 RT101 - RT103 1 RT121 1 RT131 - RT137 1 RT151 - RT152 1 RT161 - RT168 1 RT401 - RT412 1 RT431 - RT447 1 RT451 - RT469 1 RT471 - RT499

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 18 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group**  **Variable Number** 1 RT501 - RT535 1 RT551 - RT568 1 RT571 - RT591 1 RT601 - RT657 1 RT671 - RT673 1 RT681 - RT682 1 RT691 - RT699 1 RT701 - RT704 1 RT711 - RT717 1 RT741 - RT757 1 RT776 - RT777 1 RT781 - RT784 1 RT801 - RT803 1 RT811 - RT814 1 RT831 - RT837 1 RT861 - RT864 1 RT876 - RT880 1 RT931 - RT932 1 RT945 - RT949 1 RT951 - RT955 1 RT966 - RT967 1 RU001 - RU006 1 RU016 - RU017 1 RU031 - RU032 1 RU051 - RU052 1 RU059 - RU062 1 RU081 - RU083 1 RU101 - RU102 1 RU121 - RU132 1 RU801 - RU809 1 RU831 - RU841

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 19 of 51 **BOEING SERVICE BULLETIN 747-53A2465**2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of the inspections shown in this service bulletin will ensure the structural integrity of the nose wheel well top panel and side panels. Cracks in the top panel or side panel webs and stiffeners that are not found and repaired could become large and cause in flight depressurization and loss of structural integrity. Three operators have told Boeing about nose wheel well side panel web cracks that were found on four airplanes with 15,900 - 32,018 flight cycles. The cracks that were found were 1.5 inch to 14.5 inch long. In addition, a 17.5 inch long crack was found in the side panel web on Boeing's 747-400 Fatigue Test airplane at 58,890 pressure cycles. One operator has also reported a 13 inch long nose wheel well top panel web crack on one airplane. This airplane had flown 15,726 total flight cycles. Two operators have also reported nose wheel well side panel horizontal stiffener cracks on two airplanes. On one airplane with 19,577 flight cycles, a 12 inch long stiffener crack was found. On the other airplane with 31,863 flight cycles, 9 inch and 13 inch long stiffener cracks were found. Revision 1 was sent to add instructions for visual and surface High Frequency Eddy Current (HFEC) inspection of more nose wheel well sidewall stiffeners. Instructions for the inspection of all of the stiffeners between STA 320 and STA 340 and the lower stiffener between STA 300 and 320 have been added. Revision 2: After the initial release of this service bulletin, two operators have told Boeing that large sidewall panel web cracks (up to 12 inches long) were found during visual inspection on two airplanes. On one airplane, a 12 inch long side panel crack was found 1,178 flight cycles after the ultrasonic inspections shown in the initial release and Revision 1 of this service bulletin was accomplished. On the other airplane, multiple side panel cracks (up to 8.8 inches long) were found approximately 3,500 flight cycles after the ultrasonic inspection was accomplished. Revision 2 was sent to change the inspection method for the sidewall and top panel webs. Two operators have reported that large sidewall panel cracks (up to 12 inches long) were found during visual inspections on two airplanes. On one airplane, a 12 inch long side panel crack was found approximately 1,178 flight cycles after the ultrasonic inspections shown in the initial release and Revision 1 of this service bulletin was accomplished. On the other airplane, multiple side panel cracks (up to 8.8 inches long) were found approximately 3,500 flight cycles after the ultrasonic inspection was accomplished. The ultrasonic inspection of the web has been removed from this service bulletin. Instead, operators should do an external detailed inspection of the sidewall panel webs and the top panel (on Group 1 airplanes only) from inside the nose wheel well. This inspection should be repeated every 1,000 flight cycles. The inspection of the stiffeners common to the sidewall panel and top panel has not been changed. Also, the effectivity is divided into two groups due to differences in the top panel web. Airplanes with a nose cargo door (Group 2 airplanes) have a thicker top panel web than Group 1 airplanes. An inspection is not necessary on the thicker top panel web. References to FAA NPRM 2001-NM-179-AD have been added.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 20 of 51 **BOEING SERVICE BULLETIN 747-53A2465**Revision 3: After Revision 2 of this service bulletin, an operator reported an in flight decompression of an airplane with 27,241 flight cycles. Upon inspection, the nose wheel well right hand side panel web was torn open between STA 260 and STA 280, and from WL 160 to WL 170. The airplane landed safely, however, the decompression resulted in deployment of the oxygen masks and a decision by the crew to conduct an air turn back. In addition, the decompression caused damage to the Nose Landing Gear doors and adjacent structure. Revision 3 was sent to recommend that operators inspect Area 1 and Area 2 within 100 flight cycles or 90 days after the release date of Revision 3, whichever is sooner, on airplanes with 20,000 or more flight cycles. This recommendation is to address an immediate concern that airplanes with 20,000 or more flight cycles could have large cracks that can cause in flight depressurization. Table 3 has been added to Paragraph 1.E., Compliance, to incorporate the urgent inspection requirement for Area 1 and Area 2. Revision 3 does not affect Area 3 inspections. Revision 4 was sent to change the Area 1 and Area 2 repeat inspection interval and method for airplanes with 20,000 total flight cycles or more. When affected airplanes reach 20,000 total flight cycles, start to do repeated detailed and UT inspections of Area 1 and Area 2 every 500 flight cycles. Also, the repeat inspection interval for Area 3 has been changed from every 6,000 flight cycles to every 1,500 flight cycles. Figures 1 and 2 have been changed to include inspection of the web from STA 260 to STA 270 along WL 140. Since Revision 4 of this service bulletin, Boeing has received six additional reports of cracks in the nose wheel well side panels and/or side panel stiffeners. Two of the reports were on airplanes with 17,320 and 21,623 flight cycles. The other four reports were on airplanes with between 13,541 and 13,828 flight cycles. Boeing has determined that all the reported nose wheel well cracks were caused by fatigue. Furthermore, the nose wheel well top and side panels have been determined to be structure that could develop Widespread Fatigue Damage (WFD). For more information about WFD, refer to 747-SL-53-088. Service history and Boeing analysis show that fatigue cracking in the NWW top and side panels before 16,000 total flight cycles will be confined to a single bay between web stiffeners. Boeing has determined that cracking in a single stiffener bay is not an airplane safety concern. However, beyond 16,000 total flight cycles, WFD could result in cracking across multiple stiffener bays and a depressurization event significant enough to affect the structural integrity of the fuselage. In order to detect and repair possible cracking, and prevent a possible depressurization event, Boeing recommends that operators accomplish the inspections given in this service bulletin. Due to the possibility that the Federal Aviation Administration (FAA) will issue a new Airworthiness Directive to address cracking before 16,000 total flight cycles, the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web is being reduced to 13,000 total flight cycles. Revision 5 is sent to reduce the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web, and to clarify inspection requirements in Figures 1, 2, and 3. Other minor changes have also been made. A detailed list of changes is given in the Revision Transmittal Sheet section of Revision 5. Boeing Structural Item Interim Advisory SIIA 747-129 is related to this service bulletin. Boeing Service Related Problems (SRP) 747-SRP-53-0133, 747-SRP-53-0231, and 747-SRP-53-0408 are related to this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 21 of 51 **BOEING SERVICE BULLETIN 747-53A2465**Boeing Fleet Team Digest (FTD) articles 747 FTD 53-12006 and 747 FTD 53-04002 are related to this service bulletin. **D. Description** AREA 1 - Sidewall Panel Web at WL 150, WL 160, and WL 170: Open the Nose Landing Gear doors. Do a detailed inspection (and a UT inspection, if over 20,000 total flight cycles) of the Nose Wheel Well side panel for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Repair web cracks as given in the Structural Repair Manual or ask Boeing for repair data. AREA 2 - Sidewall Panel Web at WL 140 and WL 180 and Top Panel Web: Open the Nose Landing Gear doors. Do a detailed inspection (and a UT inspection, if over 20,000 total flight cycles) of the Nose Wheel Well side panel and top panel webs for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Repair web cracks as given in the Structural Repair Manual or ask Boeing for repair data. AREA 3 - Sidewall Panel and Top Panel Stiffeners: Get internal access to the Nose Wheel Well side panels and top panel. Do detailed inspections and surface High Frequency Eddy Current (HFEC) inspections of the longitudinal stiffeners for cracks. If no cracks are found, put the airplane back in serviceable condition. If cracks are found, repair before any more flights. Replace cracked stiffeners, or ask Boeing for repair data. Do the AREA 1, AREA 2, and AREA 3 inspections again at the times given in this service bulletin. Revision 1 - No more work is necessary on airplanes inspected as shown in the initial release of this service bulletin. However, for airplanes that had accomplished a prior inspection per the initial release of this service bulletin, at the time of the next scheduled inspection, do the inspections as shown in this revision. All inspections accomplished after receipt of Revision 1 of this service bulletin shall be done as shown in Revision 1. Revision 2 - More work is necessary on airplanes inspected as shown in the initial release or Revision 1 of this service bulletin. Begin to do inspections in Area 1 and Area 2 as defined in this revision within 1,000 flight cycles of the last inspection done as shown in the initial release or Revision 1 of this service bulletin. Continue to do inspections in Area 3 as defined in this revision within 6,000 flight cycles of the last inspection done as shown the initial release or Revision 1 of this service bulletin. Revision 3 - For airplanes with 19,000 or more total flight cycles that have not been previously inspected as shown in a previous release of this service bulletin, the initial Compliance threshold has been changed. Refer to Table 3 in Paragraph 1.E., Compliance. For airplanes with less than 19,000 flight cycles, no more work is required per Revision 3, but inspections should be completed as specified in paragraph 1.E., Table 1 and Table 2. Refer to paragraph 1.E. for detailed compliance information. Revision 4 - More work may be necessary on airplanes previously inspected as shown in earlier releases of this service bulletin. In Area 1 and Area 2, when affected airplanes reach 20,000 total flight cycles, start to do repeated detailed and UT inspections of Area 1 and Area 2 every 500 flight cycles. In Area 3, do repeated detailed and HFEC inspections every 1,500 flight cycles. Refer to Paragraph 1.E., Compliance.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 22 of 51 **BOEING SERVICE BULLETIN 747-53A2465**Revision 5 - No more work is necessary on airplanes inspected in accordance with the Revision 4 of this service bulletin. However, this revision reduces the initial threshold for inspection of the nose wheel well sidewall panel webs and top panel web. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 113, 114 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747- 400, 747-400D, 747SP, 747SR **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 113, 114 747-200C, 747-200F, 747-400F **E. Compliance** Federal Aviation Administration (FAA) Airworthiness Directive AD 2006-22-15 is related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the revised compliance tasks and times given in this service bulletin mandatory. **TABLE 1: Inspections for Airplanes With Less Than 15,000 Total Flight-Cycles as of the Revision 5 date of this service bulletin.**  **Repeat Inter val Not to Ex** **ceed (Flight Cycles)**  **Action Initial Threshold (Use**  **whichever occurs later) Flight-Cycles**  **Total Flight- Cycles**  1,000 (a) AREA 1: External Detailed Inspection of the Sidewall Panel Web at WL 150, WL 160, and WL 170 for Cracks. Within 1,000 flight cycles after the Revision 5date of this service bulletin. 13,000

AREA 2: External Detailed Inspection of the Sidewall Panel Web at WL 140 and WL 180 and Top Panel Web for Cracks. (a) When the airplane has 16,000 total flight cycles, continue to inspect as given in TABLE 2.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 23 of 51 **BOEING SERVICE BULLETIN 747-53A2465 TABLE 2: Inspections for Airplanes With Less Than 19,000 Total Flight-Cycles as of December 11, 2006**  **(the effective date of AD 2006-22-15) Repeat Interval Not to Exceed**  **(Flight-Cycles) Action**  **Initial Threshold (Use whichever occurs later)**  **Detailed and Surface HFEC** **Detailed In spection**  **Flight-Cycles Total Flight-**  **Cycles**

- 1,000 (a) AREA 1: External Detailed Inspection of the Sidewall Panel Web at WL 150, WL 160, and WL 170 for Cracks. 1,000 (after May 10, 2005) 16,000

AREA 2: External Detailed Inspection of the Sidewall Panel Web at WL 140 and WL 180 and Top Panel Web for Cracks. 1,500 (b)

- AREA 3: Internal Detailed and HFEC In- spection of the Sidewall Panel and Top Panel Stiffeners for Cracks.1,000 (after January 27, 2005) (a) When the airplane has 20,000 total flight cycles, continue to inspect as given in TABLE 3. (b) If previously inspected as given in an earlier release of this service bulletin, repeat the inspection within 6,000 flight cycles of the last inspection, or within 1,500 flight cycles after December 11, 2006, whichever occurs first. **TABLE 3: Inspections for Airplanes With 19,000 Total Flight-Cycles or more as of December 11, 2006 (the effective date of AD 2006-22-15)**  **Repeat Interval Not to Ex ceed (Flight-Cycles)**  **Action Initial Threshold (Use whichever oc-**  **curs later) Detailed and**  **Surface HFEC**  **Detailed and UT In**  **spection Days**  **Flight-Cycles Total** **Flight Cycles** **(Use whichever occurs first)**

- 500 AREA 1: External Detailed and UT In- spections of the Sidewall Panel Web at WL 150, WL 160, and WL 170 for Cracks. 90 (after May 10, 2005) 100 (after May 10, 2005) 20,000

AREA 2: External Detailed and UT Inspections of the Sidewall Panel Web at WL 140 and WL 180 and Top Panel Web for Cracks. 1,500 (a)

- AREA 3: Internal Detailed and HFEC Inspection of the Sidewall Panel and Top Panel Stiffeners for Cracks. - 1000 (after Jan- uary 27, 2005) -

(a) If previously inspected as given in an earlier release of this service bulletin, repeat the inspection within 6,000 flight cycles of the last inspection, or within 1,500 flight cycles after December 11, 2006, whichever occurs first.
**NOTE:**On airplanes previously inspected as given in earlier releases of this service bulletin, continue to do repeat inspections using the repeat intervals in this service bulletin.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 24 of 51 **BOEING SERVICE BULLETIN 747-53A2465 NOTE:** Modification in accordance with Service Bulletin 747-53A2562 or Service Bulletin 747-53A2808, as applicable, terminates the inspection requirements of this service bulletin. **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. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the accomplishment of the inspections and corrective actions defined in this service bulletin as an alternate method of compliance to the requirements of paragraphs (f), (g), (h), (i), and (j) of AD 2006-22-15. This AMOC only applies to the areas inspected, repaired, or modified in accordance with 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 (p) of the AD. All provisions of AD 2006-22-15 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. **G. Manpower** The table below shows an estimate of the man-hours necessary to do this inspection for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator man-hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. **Group 1-2: Area 1 Inspection as given in Figure 1**  **Elapsed Time (Hours) Man-Hours**  **Number of Persons Task**  0.5 1 2 Open Access 12.5 25 2 Examine 0.5 1 2 Close Access 13.5 27 TOTAL FOR EACH AIRPLANE

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 25 of 51 **BOEING SERVICE BULLETIN 747-53A2465 Group 1:**  **Area 2 Inspection as given in Figure 2 Elapsed Time (Hours)**  **Man-Hours Number of Persons**  **Task** 0.5 1 2 Open Access 9 18 2 Examine 0.5 1 2 Close Access 10 20 TOTAL FOR EACH AIRPLANE **Group 2: Area 2 Inspection as given in Figure 3**  **Elapsed Time (Hours) Man-Hours**  **Number of Persons Task**  0.5 1 2 Open Access 4 8 2 Examine 0.5 1 2 Close Access 5 10 TOTAL FOR EACH AIRPLANE **Group 1-2: Area 3 Inspection as given in Figure 4**  **Elapsed Time (Hours) Man-Hours**  **Number of Persons Task**  4.5 9 2 Open Access 27 54 2 Examine 4.5 9 2 Close Access 36 72 TOTAL FOR EACH AIRPLANE
**NOTE:**More time will be necessary for repairs if cracks are found. **H. Weight and Balance Changes** None **I. Electrical Load Data** 747-400: Not changed All other 747 models: Not applicable **J. References** 1. Existing Data: a. Boeing Service Bulletin 747-53A2562, 747-53A2808

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 26 of 51 **BOEING SERVICE BULLETIN 747-53A2465**b. Boeing Service Letter 747-SL-51-048, 747-SL-53-088 c. Boeing Service Related Problem (SRP) 747-SRP-53-0133, 747-SRP-53-0231, 747-SRP-53-0408 d. Boeing Structural Item Interim Advisory (SIIA) 747-129 e. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2006-22-15 f. Service Bulletin Index D6-30300 g. 747 Fleet Team Digest (FTD) 53-04002, 53-12006 h. 747 Non-Destructive Testing (NDT) Manual Part 4, 53-10-12, Part 6, 51-00-00 i. 747-100/200/300 Aircraft Maintenance Manual (AMM) 09-11-00, 25-25-01, 25-27-01, 32-00-30, 53-21-02 j. 747-100/200/300 Structural Repair Manual (SRM) 53-10-04 k. 747-400 Aircraft Maintenance Manual (AMM) 09-11-00, 25-25-01, 25-27-01, 32-00-30, 53-21-02 l. 747-400 Structural Repair Manual (SRM) 53-10-14 m. 747-400F Structural Repair Manual (SRM) 53-10-14 n. 747-400SF Structural Repair Manual (SRM) 53-10-14 o. 747-SP Structural Repair Manual (SRM) 53-19-02 p. 747-E4B Structural Repair Manual (SRM) 53-10-04 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. **K. Publications Affected** 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS but no new DTIs are necessary.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 27 of 51 **BOEING SERVICE BULLETIN 747-53A2465 L. Interchangeability and Intermixability of Parts**  None. **M. Software Accomplishment Summary** Not affected.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 28 of 51 **BOEING SERVICE BULLETIN 747-53A2465 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** None. **B. Industry Support Information** Boeing warranty remedies are not available for the inspection and repair procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: None. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 29 of 51 **BOEING SERVICE BULLETIN 747-53A2465**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 30 of 51 **BOEING SERVICE BULLETIN 747-53A2465**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:**KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. Boeing Service Letter 747-SL-51-048, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 8. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 9. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 31 of 51 **BOEING SERVICE BULLETIN 747-53A2465**10. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "as given in" are included in the instruction, the procedure in the Boeing document must be used. **B. WORK INSTRUCTIONS INSPECTION OF AREA 1 - NOSE WHEEL WELL SIDEWALL PANEL WEB AT WL 150, WL 160,**  **AND WL 170** 1. PART 1 - ACCESS AND INSPECTION a. Install the ground locks on the landing gear. Refer to 747-100/200/300 AMM 09-11-00 or 747-400 AMM 09-11-00. **WARNING:**MAKE SURE THAT ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE DOOR OPERATION AREA. FAST MOVEMENT OF THE DOORS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. b. Open the nose landing gear doors and install door locks. Refer to 747-100/200/300 AMM 32-00-30 or 747-400 AMM 32-00-30. c. Do inspections of the side panel webs for cracks as given in FIGURE 1. d. If no cracks are found, continue to PART 2. Do the inspections in PART 1 again at the times given in Paragraph 1.E., Compliance. e. If cracks are found, repair before any more flights. For repair of web cracks, refer to 747-100/200/300 SRM 53-10-04; or 747-400 SRM 53-10-14; or 747-400F SRM 53-10-14; or 747-400SF SRM 53-10-14 ; or 747-SP SRM 53-19-02; or 747-E4B SRM 53-10-04. f. If cracks are found common to the side panel, do a detailed inspection of the vertical beams and the horizontal stiffeners in the areas where cracks were found, as given in FIGURE 5. Inspect within a 20 inch radius of where web cracks were found. If cracks are found during this secondary inspection, contact Boeing for repair data. g. Continue to PART 2. Do the inspections in PART 1 again at the times given in Paragraph 1.E., Compliance. 2. PART 2 - RESTORATION **WARNING:**MAKE SURE THAT ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE DOOR OPERATION AREA. FAST MOVEMENT OF THE DOORS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. a. Remove the door locks and close the nose landing gear doors. Refer to 747-100/200/300 AMM 32-00-30 or 747-400 AMM 32-00-30. b. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 32 of 51 **BOEING SERVICE BULLETIN 747-53A2465 INSPECTION OF AREA 2 - NOSE WHEEL WELL SIDEWALL PANEL WEB AT WL 140 AND WL**  **180, AND TOP PANEL WEB:** 1. PART 1 - ACCESS AND INSPECTION a. Install the ground locks on the landing gear. Refer to 747-100/200/300 AMM 09-11-00 or 747-400 AMM 09-11-00. **WARNING:**MAKE SURE THAT ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE DOOR OPERATION AREA. FAST MOVEMENT OF THE DOORS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. b. Open the nose landing gear doors and install door locks. Refer to 747-100/200/300 AMM 32-00-30 or 747-400 AMM 32-00-30.

c. **Group 1:** Do inspections of the top panel and side panel webs for cracks as given in FIGURE 2. d. **Group 2:** Do inspections of the side panel webs for cracks as given in FIGURE 3. e. If no cracks are found, continue to PART 2. Do the inspections in PART 1 again at the times given in Paragraph 1.E., Compliance. f. If cracks are found, repair before any more flights. For repair of web cracks, refer to 747-100/200/300 SRM 53-10-04; or 747-400 SRM 53-10-14; or 747-400F SRM 53-10-14; or 747-400SF SRM 53-10-14 ; or 747-SP SRM 53-19-02; or 747-E4B SRM 53-10-04. g. If cracks are found common to the side panel, do a detailed inspection of the vertical beams and the horizontal stiffeners in the areas where cracks were found, as given in FIGURE 5. Inspect within a 20 inch radius of where cracks were found. If cracks are found during this secondary inspection, contact Boeing for repair data. h. **Group 1:** If cracks are found common to the top panel, do a detailed inspection of the longitudinal stiffeners, the floor beam lower chords, the floor beam webs, and the vertical beam upper ends in the areas where cracks were found, as given in FIGURE 6. Inspect within a 20 inch radius of where cracks were found. If cracks are found during this secondary inspection, contact Boeing for repair data. i. Continue to PART 2. Do the inspections in PART 1 again at the times given in Paragraph 1.E., Compliance. 2. PART 2 - RESTORATION **WARNING:**MAKE SURE THAT ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE DOOR OPERATION AREA. FAST MOVEMENT OF THE DOORS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. a. Remove the door locks and close the nose landing gear doors. Refer to 747-100/200/300 AMM 32-00-30 or 747-400 AMM 32-00-30. b. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 33 of 51 **BOEING SERVICE BULLETIN 747-53A2465 INSPECTION OF AREA 3 - NOSE WHEEL WELL SIDEWALL PANEL AND TOP PANEL STIFFENERS**  1. PART 1 - ACCESS AND INSPECTION a. Remove the equipment that follows from the main deck as necessary for access to the nose wheel well top panel from STA 260 to STA 340, between LBL 20 and RBL 20. Refer to the following procedures: **AMM Subject Equipment**  747-100/200/300 AMM 25-25-01 or 747-400 AMM 25-25-01 Passenger Seats

747-100/200/300 AMM 25-27-01 or 747-400 AMM 25-27-01 Floor Covering

747-100/200/300 AMM 53-21-02 or 747-400 AMM 53-21-02 Floor Panels

b. Remove and keep the insulation blankets from the nose wheel well top panel and side panels. c. Do detailed inspections and surface HFEC inspections of the top panel and side panel stiffeners for cracks as given in FIGURE 4. d. If no cracks are found, continue to PART 2. Do the inspections in PART 1 again at the time given in Paragraph 1.E., Compliance. e. If any cracked stiffener is found, replace the cracked stiffener before further flight, or contact Boeing for repair instructions. Cracked stiffeners can be replaced using AND10139-2202 7075-T6511 extrusion. Make sure to attach the 0.75 inch flange (of the new stiffener) to the web using a filler that has a thickness equal to the depth of the joggle in the production stiffener. After cracked stiffeners are repaired or replaced, continue to PART 2. Do the inspections in PART 1 again at the time given in Paragraph 1.E., Compliance. 2. PART 2 - RESTORATION a. Install the insulation blankets that were removed from the nose wheel well top panel and side panels. b. Install any equipment that was removed from the main deck for access. c. Put the airplane back to a serviceable condition.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5: July 11, 2013 34 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 1: INSPECTION OF AREA 1 - ALL AIRPLANES**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 35 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 1: INSPECTION OF AREA 1 - ALL AIRPLANES**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 36 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  For cracks. (a)

- Detailed Inspection Side Panel Webs Inspect 1 On airplanes with 20,000 total flight cycles or more, do a UT inspection for cracks. (b) 747 NDT Part 4, 53-10-12 UT Inspection

(a) Typically, the webs crack at the lower edge of the bonded strap on the sidewall web. Pay particular attention to this location. (b) The UT inspection is only necessary along the lower edge of the bonded strap. If paint was removed to do the UT inspection, it is not necessary to reapply paint. Make sure that primer is present in areas where paint was removed. Apply primer if necessary. If necessary, reapply organic corrosion inhibitor to the affected area.

**FIGURE 1: INSPECTION OF AREA 1 - ALL AIRPLANES (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 37 of 51 **BOEING SERVICE BULLETIN 747-53A2465 This Figure applies only to: Group 1.** 

**FIGURE 2: INSPECTION OF AREA 2 (SHEET 1 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 38 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 2: INSPECTION OF AREA 2**  **(SHEET 2 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 39 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 2: INSPECTION OF AREA 2**  **(SHEET 3 OF 4)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 40 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  For cracks (a)

- Detailed Inspection Side Panel Webs Inspect 1 On airplanes with 20,000 total flight cycles or more (b) (c) 747 NDT Part 4, 53-10-12 UT Inspection

For cracks

- Detailed Inspection Top Panel Webs Inspect 2 On airplanes with 20,000 total flight cycles or more (c) (d) 747 NDT Part 4, 53-10-12 UT Inspection (a) At WL 180, the sidewall webs typically crack at the lower edge of the bonded strap. At WL 140, thesidewall webs typically crack at the upper edge of the bonded strap. Pay particular attention to these locations. (b) At WL 180, do the UT inspection along the lower edge of the bonded strap. At WL 140 from STA 260 toapproximately STA 270, do the UT inspection along the edge of the fairing cover. At WL 140 from approximately STA 270 to STA 320, do the UT inspection along the upper edge of the bonded strap. (c) If paint was removed to do the UT inspection, it is not necessary to reapply paint. Make sure that primer is present in areas where paint was removed. Apply primer if necessary. If necessary, reapply organic corrosion inhibitor to the affected area. (d) At RBL 10, BL 0, and LBL 10, do the UT inspection along the inboard and outboard edges of the bonded strap. At RBL 20 and LBL 20, do the UT inspection along only the inboard edge of the bonded strap.

**FIGURE 2: INSPECTION OF AREA 2 (SHEET 4 OF 4)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 41 of 51 **BOEING SERVICE BULLETIN 747-53A2465 This Figure applies only to: Group 2.** 

**FIGURE 3: INSPECTION OF AREA 2 (SHEET 1 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 42 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 3: INSPECTION OF AREA 2**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 43 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  For cracks (a)

- Detailed Inspection Side Panel Webs Inspect 1 On airplanes with 20,000 total flight cycles or more (b) (c) 747 NDT Part 4, 53-10-12 UT Inspection

(a) At WL 180, the sidewall webs typically crack at the lower edge of the bonded strap. At WL 140, the sidewall webs typically crack at the upper edge of the bonded strap. Pay particular attention to these locations. (b) At WL 180, do the UT inspection along the lower edge of the bonded strap. At WL 140 from STA 260 toapproximately STA 270, do the UT inspection along the edge of the fairing cover. At WL 140 from approximately STA 270 to STA 320, do the UT inspection along the upper edge of the bonded strap. (c) If paint was removed to do the UT inspection, it is not necessary to reapply paint. Make sure that primer is present in areas where paint was removed. Apply primer if necessary. If necessary, reapply organic corrosion inhibitor to the affected area.

**FIGURE 3: INSPECTION OF AREA 2 (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 44 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 4: INSPECTION OF AREA 3 - ALL AIRPLANES**  **(SHEET 1 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 45 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 4: INSPECTION OF AREA 3 - ALL AIRPLANES**  **(SHEET 2 OF 3)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 46 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  (a) (c)

- Detailed Inspection Top Panel and Side Panel Stiffeners Inspect 1 (b) (c) (d) 747 NDT Part 6, 51- 00-00, Procedure 4 or 23 Surface HFEC Top Panel and Side Panel Stiffeners Inspect 2

(a) Do an internal detailed inspection of the side panel stiffeners and top panel stiffeners for cracks. (b) Do a surface HFEC inspection for cracks parallel to (along the length of) the radius using a "transverse scan" method as shown in 747 NDT Part 6, 51-00-00, Procedure 4, Figure 11, or 747 NDT Part 6, 51- 00-00, Procedure 23, Figure 13. If a strap, or filler, or angle is installed in the radius of the stiffener, do the surface HFEC inspection of the stiffener surface that is opposite the radius, as shown. (c) Only the left side stiffeners are shown in the illustration, but inspection of the right side stiffeners is also required. (d) At STA 260 - 270, there is a reinforcing angle that prevents the surface HFEC inspection of the radius of the stiffener. Inspect the radius of the reinforcing angle as specified in note (b).

**FIGURE 4: INSPECTION OF AREA 3 - ALL AIRPLANES (SHEET 3 OF 3)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 47 of 51 **BOEING SERVICE BULLETIN 747-53A2465 FIGURE 5: SECONDARY INSPECTION OF SIDE PANEL VERTICAL BEAMS AND HORIZONTAL STIFFENERS**  **- ALL AIRPLANES (SHEET 1 OF 2)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 48 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown in the table below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  as necessary, from the nose wheel well side panel. - - Insulation Blankets Remove / Keep 1 (not shown) Inspect the horizontal stiffeners and the vertical beams for cracks. Inspection of the entirearea is not required. Only inspect within a 20 inch radius of cracks that were found in the side panel. - Detailed Inspec- tion Side Panel Horizontal Stiffeners Inspect 2
Side Panel Vertical Beams

as necessary, from the nose wheel well side panel. - - Insulation Blankets (kept) Install 3 (not shown)

**FIGURE 5: SECONDARY INSPECTION OF SIDE PANEL VERTICAL BEAMS AND HORIZONTAL STIFFENERS - ALL AIRPLANES**  **(SHEET 2 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 49 of 51 **BOEING SERVICE BULLETIN 747-53A2465 This Figure applies only to: Group 1.** 

**FIGURE 6: SECONDARY INSPECTION OF LONGITUDINAL STIFFENERS, FLOOR BEAM LOWER CHORDS, FLOOR BEAM WEBS, AND VERTICAL BEAM UPPER ENDS**  **(SHEET 1 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 50 of 51 **BOEING SERVICE BULLETIN 747-53A2465**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES REFERENCES**  **PROCEDURE NAME**  **TASK STEP**  as necessary. - 747-100/200/300 AMM 25-25-01 or 747-400 AMM 25- 25-01 Passenger Seats Remove / Keep 1 (not shown)

- 747-100/200/300 AMM 25-27-01 or 747-400 AMM 25- 27-01 Floor Coverings

- 747-100/200/300 AMM 53-21-02 or 747-400 AMM 53- 21-02 Floor Panels

as necessary, from the nose wheel well side panel. - - Insulation Blankets Inspect the longitudinal stiffeners that are on the top of the panel for cracks. Inspection of all stiffeners is not required, only inspect stiffeners within a 20 inch radius of cracks that were found in the top panel. - Detailed Inspection Longitudinal Stiffen- ers Inspect 2

For cracks. It is only necessary to inspect floor beams and vertical beams within a 20 inch radius of the cracks that were found in the top panel. - Detailed Inspection Floor Beam Lower Chords Inspect 3

Floor Beam WebsVertical Beam Upper Ends as necessary, from the nose wheel well side panel. - - Insulation Blankets (kept) Install 4 (not shown) as necessary. - 747-100/200/300 AMM 53-21-02 or 747-400 AMM 53- 21-02 Floor Panels (kept)

- 747-100/200/300 AMM 25-27-01 or 747-400 AMM 25- 27-01 Floor Coverings (kept)

- 747-100/200/300 AMM 25-25-01 or 747-400 AMM 25- 25-01 Passenger Seats (kept)

**FIGURE 6: SECONDARY INSPECTION OF LONGITUDINAL STIFFENERS, FLOOR BEAM LOWER CHORDS, FLOOR BEAM WEBS, AND VERTICAL BEAM UPPER ENDS**  **(SHEET 2 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 05, 2001 747-53A2465 Revision 5 July 11, 2013 51 of 51 **BOEING SERVICE BULLETIN 747-53A2465**