# Boeing Alert Service Bulletin 747-53A2895: No revision named - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2020-0095, the docket of AD 2020-08-12. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 747-53A2895](https://openairdocs.org/service-documents/boeing/747-53a2895.md) - Title as filed: 747-53A2895-00--RB - BOEING - Pages: 124 - PDF: https://openairdocs.org/files/sha256/c4/b3/c4b34ec869f77a71b2970d58cb643057337f089a19d93cac9e9726fe40a73476 - Page: https://openairdocs.org/service-documents/boeing/747-53a2895/file/c4b34ec869f7 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 747 Requirements Bulletin ALERT Number: 747-53A2895 RB Original Issue: September 12, 2019 ATA System: 5300 5321 SUBJECT: FUSELAGE - Skin - Section 41 and 42, Skin Lap Joint Inspection and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991ECCN: Copyright © 2019 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. Original Issue: September 12, 2019 747-53A2895 RB 1 of 124 2.0 ### Page 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 2 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT BLANK PAGE ### Page 3 Table of Contents 1 . E F F E C T I V I T Y ................................................ 5 A. Airplanes ................................................ 5 B . S p a r e s A f f e c t e d ............................................ 6 2. CONCURRENT REQUIREMENTS ..................................... 6 3 . C O M P L I A N C E ................................................ 6 4. APPROVAL ................................................. 8 5. ACCOMPLISHMENT INSTRUCTIONS .................................. 9 A. General Information .......................................... 9 B. Work Instructions ........................................... 1 1 FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION L EFT SIDE [Group 1-3] . 15 FIGURE 2: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION R IGHT SIDE [Group 1] . . 20 FIGURE 3: SECTION 41 - STRINGER S- 23 - LAP JOINT - MODIFICATION LEFT SIDE [Group 1-2] . 24 FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE [Group 1-3] . 30 FIGURE 5: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION R IGHT SIDE [Group 2-3] . 36 FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE [Group 3] . . 40 FIGURE 7: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICAT ION INSPECTIONS LEFT SIDE [Group 1-3] ........................................ 4 6 FIGURE 8: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICAT ION INSPECTIONS RIGHT SIDE [Group 1-3] ........................................ 4 9 FIGURE 9: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICA TION INSPECTIONS LEFT SIDE [Group 1-3] ........................................ 5 2 FIGURE 10: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFIC ATION INSPECTIONS RIGHT SIDE [Group 1-3] ........................................ 5 5 FIGURE 11: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE [Group 4-6] . 58 FIGURE 12: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE [Group 4-6] . 63 FIGURE 13: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE [Group 4-5] . 68 FIGURE 14: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE [Group 4-6] . 76 FIGURE 15: SECTION 42 - STRINGER S-44 - LAP JOINT - MODIFICATION LEFT SIDE [Group 4-6] . 84 FIGURE 16: SECTION 42 - STRINGER S-44 - LAP JOINT - MODIFICATION RIGHT SIDE [Group 4] . 89 FIGURE 17: SECTION 42 - STRINGER S-44 - LAP JOINT - MODIFICATION RIGHT SIDE [Group 5-6] . 94 FIGURE 18: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE [Group 6] . . 99 FIGURE 19: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICA TION INSPECTIONS LEFT SIDE [Group 4-6] ....................................... 1 0 7 FIGURE 20: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICA TION INSPECTIONS RIGHT SIDE [Group 4-6] ....................................... 1 1 0 FIGURE 21: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFIC ATION INSPECTIONS LEFT SIDE [Group 4-6] ....................................... 1 1 3 FIGURE 22: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFIC ATION INSPECTIONS RIGHT SIDE [Group 4-6] ....................................... 1 1 6 FIGURE 23: SECTION 42 - STRINGER S-44 - LAP JOINT - POST-MODIFIC ATION INSPECTIONS LEFT SIDE [Group 4-6] ....................................... 1 1 9 FIGURE 24: SECTION 42 - STRINGER S-44 - LAP JOINT - POST-MODIFIC ATION INSPECTIONS RIGHT SIDE [Group 4-6] ....................................... 1 2 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 3 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 4 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 4 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT BLANK PAGE ### Page 5 Commercial Airplanes 747 Requirements Bulletin ALERT Number: 747-53A2895 RB Original Issue: September 12, 2019 ATA System: 5300 5321 SUBJECT: FUSELAGE - Skin - Section 41 and 42, Skin Lap Joint Inspection and Modification THIS DOCUMENT IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS DOCUMENT TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE NEW OWNER. THIS IS AN ENHANCED REQUIRED FOR COMPLIANCE DOCUMENT. THE BOEING PROCESSES USED TO CREATE THE SERVICE BULLETIN (SB) AND THE REQUIREMENTS BULLETIN (RB) ENSURE THAT THE INFORMATION BETWEEN "RC START" AND "RC END" IN THE SB ARE IDENTICAL TO THE INFORMATION IN THE SAME SECTIONS (COMPLIANCE, WORK INSTRUCTIONS…) OF THE RB WHICH THE SB REFERS TO AS THE RELATED DOCUMENT. 1. EFFECTIVITY A. Airplanes This bulletin is applicable to 747-8, 747-8F Airplane(s), line number(s) 1420-1560 in 6 Group(s). Where the effectivity is presented with hyphens between line numbers, the airplane applicability means "through" and "inclusive", e.g. line numbers 1-9 means line numbers 1 through 9 inclusive. The Variable Number table below includes all affected airplanes up to Line Number 1557. Affected airplanes after Line Number 1557 will show up as available as they are added to Maintenance Performance Toolbox DESCRIPTIONCONFIGURATIONGROUP 747-8 Airplanes, line numbers 1434 - 1456.-1 747-8 Airplanes, line numbers 1459 - 1492.-2 747-8 Airplanes, line numbers 1494 and on.-3 747-8F Airplane, line number 1420.-4 747-8F Airplanes, line numbers 1421 - 1491.-5 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 5 of 124 ### Page 6 DESCRIPTIONCONFIGURATIONGROUP 747-8F Airplanes, line numbers 1493 and on.-6 B. Spares Affected None. 2. CONCURRENT REQUIREMENTS None. 3. COMPLIANCE The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to Requirements Bulletin 747-53A2895 RB. The Airworthiness Directive will make the compliance tasks and times given in Requirements Bulletin 747-53A2895 RB mandatory. Accomplish the required actions, based on the applicable conditions in Tables 1, 2, 3, and 4, in accordance with the Accomplishment Instructions. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION or an OPTION, do all of the ACTION numbers for that CONDITION or OPTION. Group 1-3: Table 1: Structural Modification of the Left and Right Side Lap Joints at Stringers S-6 and S-23, Section 41 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 30,000 total flight cycles. Do structural modification to left and right side lap joints at stringers S-6 and S-23. All airplanes. Group 1-3: Table 2: Post-Modification Inspections of the Left and Right Side Lap Joints at Stringers S-6 and S-23, Section 41 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 15,000 flight cy- cles after accomplishing the modifications at stringers S-6 and S-23. Do internal detailed and sur- face High Frequency Eddy Current (HFEC) inspections of the left and right side skin, along the edge fastener rows of the structurally modified lap joints at stringers S-6 and S- 23 for any crack. Airplanes that have ac- complished the modifica- tion of the lap joint at S-6 and S-23. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 6 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 7 Group 1-3: Table 2: Post-Modification Inspections of the Left and Right Side Lap Joints at Stringers S-6 and S-23, Section 41 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.CONDITION 1 (ACTION 1):CONDITION 1: Contact The Boeing Compa- ny for repair instructions and do the repair. ANY CRACK FOUND. 3,000 flight cycles.-CONDITION 1 (ACTION 2): Repeat the internal detailed and surface HFEC inspec- tions of the left and right side skin, along the edge fastener rows of the structurally modi- fied lap joints at stringers S-6 and S-23 for any crack at un- repaired areas. 3,000 flight cycles.-Repeat the internal detailed and surface HFEC inspec- tions of the left and right side skin, along the edge fastener rows of the structurally modi- fied lap joints at stringers S-6 and S-23 for any crack at un- repaired areas. CONDITION 2: NO CRACK FOUND. Group 4-6: Table 3: Structural Modification of the Left and Right Side Lap Joints at Stringers S-6, S-23, Section 41 and, Stringer S-44, Section 42 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before 30,000 total flight cycles. Do structural modification to the left and right side lap joints at stringers S-6 and S- 23, and S-44. All airplanes. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 7 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 8 Group 4-6: Table 4: Post-Modification Inspections of the Left and Right Side Lap Joints at Stringers S-6, S-23, Section 41, and Stringer S-44, Section 42 Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 15,000 flight cy- cles after accomplishing the modifications at stringers S-6, S-23 and S-44. Do internal detailed and sur- face High Frequency Eddy Current (HFEC) inspections of the left and right side skin, along the edge fastener rows of the structurally modified lap joints stringers S-6, S-23, and S-44 for any crack. Airplanes that have ac- complished the modifica- tion of the lap joint at S- 6, S-23 and S-44. -Before further flight.CONDITION 3 (ACTION 1):CONDITION 3: Contact The Boeing Compa- ny for repair instructions and do the repair. ANY CRACK FOUND. 3,000 flight cycles.-CONDITION 3 (ACTION 2): Repeat the internal detailed and surface HFEC inspec- tions of the left and right side skin, along the edge fastener rows of the structurally modi- fied lap joints at stringers S- 6, S-23, and S-44 for any crack at unrepaired areas. 3,000 flight cycles.-Repeat the internal detailed and surface HFEC inspec- tions of the left and right side skin, along the edge fastener rows of the structurally modi- fied lap joints at stringers S- 6, S-23, and S-44 for any crack at unrepaired areas. CONDITION 4: NO CRACK FOUND. 4. APPROVAL This Requirements Bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this document 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 document and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this Requirements Bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this Requirements Bulletin. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 8 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 9 5. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION NOTE: 1. This is an Enhanced Required for Compliance document. There w ill be a separate Service Bulletin (SB) and a separate Requirements Bulletin (RB). If an RB is mandated by an Airworthiness Directive (AD), then all applicable requirements specified in the RB must be done. For the related SB, some locations are marked RC Start and RC End to identify the requirements that are restated from the RB. For the related SB, the areas between RC Start and RC End, including sub-steps and any figures identified between RC Start and RC End, must be done to comply with the AD. Therefore, an Alternative Method of Compliance (AMOC) is required for any deviations to steps between RC Start and RC End, including substeps and identified figures. For the related SB, the steps not between RC Start and RC End may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC; this is provided that the steps between RC Start and RC End, including sub-steps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition. Figures not required for compliance are omitted from the RB. 2. This is an Enhanced Required for Compliance document. The Boe ing processes used to create the Service Bulletin (SB) and the Requirements Bulletin (RB) ensure that the information between "RC Start" and "RC End" in the SB are identical to the information in the same sections (Compliance, Work Instructions...) of the RB which the SB refers to as the related document. 3. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance. 4. Boeing Service Letter 747-SL-51-048, Damage Reporting and Rep air 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. 5. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque Values: — Values for structural fasteners are given in 747 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 747 Aircraft Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). — Values for engine maintenance tasks are included in Chapter 70 of 747 Aircraft Maintenance Manual (AMM). Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 9 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 10 — Non-standard torque values for maintenance tasks are included in the applicable installation step. 6. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 7. Where the work instructions include installation of a kept pa rt, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 8. If it is necessary to remove more parts for access, you can r emove 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. 9. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 10. A Detailed Inspection is defined as: An intensive examinatio n of a specific item, installation or assembly to detect damage, failure or irregularity. This could include tactile assessment in which a component or assembly can be checked for tightness/security. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors and magnifying lenses may be necessary. Surface cleaning and elaborate access procedures may be required. 11. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION or an OPTION, do all of the ACTION numbers for that CONDITION or OPTION. 12. If the length of any fastener specified in this service bull etin 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. Refer to SOPM 20-50-01 for alternate full threaded fasteners (screws) needed for installation in this service bulletin. 13. Manual titles are referred to by acronyms. Refer to Paragrap h 1.J., References, for definition of the acronyms. 14. Obey all of the warnings and cautions given in the specified manual sections. 15. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-' (dash) part number. Boeing Drawing 005W0900 contains more data. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 10 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 11 16. Although 747-8P SRM 51-40-08 and 747-8F SRM 51-40-08 give in structions for installation of countersink repair washers, it is not required to install repair washers in existing countersinks under the modification doublers that are installed in accordance with this service bulletin. As an alternative to repair washers, fill existing countersinks with BMS 5-95 sealant prior to doubler installation. 17. For airplanes that operate with Reduced Vertical Separation Minimum (RVSM), skin waviness measurements as given in 747-8P SRM 51-10-03 are not required after doublers are installed in accordance with this service bulletin. 18. For airplanes that operate with Reduced Vertical Separation Minimum (RVSM), skin waviness measurements as given in 747-8F SRM 51-10-03 are not required after doublers are installed in accordance with this service bulletin. B. WORK INSTRUCTIONS Actions Required for Compliance: 1. Requirements. Group 1-3: Table 1: Structural Modification of the Left and Right Side Lap Joints at Stringers S-6 and S-23, Section 41 Refer to the list- ed procedures in SB 747-53A2895 Original Issue or later approved revisions as an accepted proce- dure Method of ComplianceActionCondition -FIGURE 1 and FIGURE 2 Group 1Do structural modification of the left and right lap joint at stringers S-6 and S-23. All airplanes. -FIGURE 3 and FIGURE 4 -FIGURE 1 and FIGURE 5 Group 2 -FIGURE 3 and FIGURE 4 -FIGURE 1 and FIGURE 5 Group 3 -FIGURE 6 and FIGURE 4 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 11 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 12 Group 1-3: Table 2: Post-Modification Inspections of the Left and Right Side Lap Joints at Stringers S-6 and S-23, Section 41 Refer to the list- ed procedures in SB 747-53A2895 Original Issue or later approved revisions as an accepted proce- dure Method of ComplianceActionCondition -FIGURE 7 and FIGURE 8 Groups 1-3Do internal detailed and sur- face High Frequency Eddy Current (HFEC) inspections of the left and right side lap joint modifications at S-6 and S-23 for any crack. Airplanes that have ac- complished the modifica- tion of the lap joint at S-6 and S-23. -FIGURE 9 andFIGURE 10 --CONDITION 1 (ACTION 1):CONDITION 1: Contact The Boeing Compa- ny for repair instructions and do the repair. ANY CRACK FOUND. -FIGURE 7 and FIGURE 8 Groups 1-3CONDITION 1 (ACTION 2): Repeat internal detailed and surface HFEC inspections of the left and right side lap joint modifications at stringers S-6 and S-23, Section 41, for any crack. -FIGURE 9 and FIGURE 10 -FIGURE 7 and FIGURE 8 Groups 1-3Repeat internal detailed and surface HFEC inspections of the left and right side lap joint modifications at stringers S-6 and S-23 for any crack. CONDITION 2: NO CRACK FOUND. -FIGURE 9 and FIGURE 10 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 12 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 13 Group 4-6: Table 3: Structural Modification of the Left and Right Side Lap Joints at Stringers S-6, S-23, Section 41, and Stringer S-44, Section 42 Refer to the list- ed procedures in SB 747-53A2895 Original Issue or later approved revisions as an accepted proce- dure Method of ComplianceActionCondition -FIGURE 11 and FIGURE 12 Group 4Do structural modification of the left and right lap joint at stringers S-6, S-23, and S-44. All airplanes. -FIGURE 13 and FIGURE 14 -FIGURE 15 and FIGURE 16 -FIGURE 11 and FIGURE 12 Group 5 -FIGURE 13 and FIGURE 14 -FIGURE 15 and FIGURE 17 -FIGURE 11 and FIGURE 12 Group 6 -FIGURE 18 and FIGURE 14 -FIGURE 15 and FIGURE 17 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 13 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 14 Group 4-6: Table 4: Post-Modification Inspections of the Left and Right Side Lap Joints at Stringers S-6, S-23, Section 41, and Stringer S-44, Section 42 Refer to the list- ed procedures in SB 747-53A2895 Original Issue or later approved revisions as an accepted proce- dure Method of ComplianceActionCondition -FIGURE 19 and FIGURE 20 Groups 4-6Do internal detailed and sur- face High Frequency Eddy Current (HFEC) inspections of the left and right side lap joint modifications at stringers S-6, S-23, and S-44, for any crack. Airplanes that have ac- complished the modifica- tion of the lap joint at S- 6, S-23 and S-44. -FIGURE 21 andFIGURE 22 -FIGURE 23 and FIGURE 24 --CONDITION 3 (ACTION 1):CONDITION 3: Contact The Boeing Compa- ny for repair instructions and do the repair. ANY CRACK FOUND. -FIGURE 19 and FIGURE 20 Groups 4-6CONDITION 3 (ACTION 2): Repeat internal detailed and surface HFEC inspections of the left and right side lap joint modifications at stringers S- 6, S-23, and S-44, for any crack. -FIGURE 21 and FIGURE 22 -FIGURE 23 and FIGURE 24 -FIGURE 19 and FIGURE 20 Groups 4-6Repeat internal detailed and surface HFEC inspections of the left and right side lap joint modifications at stringers S- 6, S-23, and S-44, for any crack. CONDITION 4: NO CRACK FOUND. -FIGURE 21 and FIGURE 22 -FIGURE 23 and FIGURE 24 2. Put the airplane back to a serviceable condition. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 14 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 15 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. STA 400 STA 340 AND STA 340 D RETROFIT 624U4105 SHEET 2 S-2L - 0000 0000000000 SKIN C RETROFIT 624U4105 SHEET 2 EXTERNAL DOUBLER STA 400 S-6L - RETROFIT 624U4105 SHEET 1 STRUCTURAL FILLER S-10L - E RETROFIT 624U4105 SHEET 2 FWD 2816614 FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 1 OF 5) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 15 of 124 ### Page 16 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT RETROFIT STA 340 624U4106 SHEET 2 S-2L SKIN H RETROF 24U410 SHEET 2 EXTERNAL DOUBLER STA 400 S-6L -G RETROFIT 624U4106 SHEET 1 STRUCTURAL FILLER S-10L - K RETROFIT 624U4106 SHEET 2 FWD 6696286 FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 2 OF 5) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 16 of 124 ### Page 17 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4106, Sheets 1 and 2. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)--SKINInspect2 (a)(c)1675U0017-7STRUCTURAL FILLERLocate3 (a)(c)1675U0017-5EXTERNAL DOUBLERLocate (a)(d)-675U0017-7STRUCTURAL FILLERDrill4 (a)(d)-675U0017-5EXTERNAL DOUBLERDrill (a)(e)(f)1675U0017-7STRUCTURAL FILLERCut5 (a)(e)(f)1675U0017-5EXTERNAL DOUBLERCut (a)(f)(g)1675U0017-5EXTERNAL DOUBLERCut6 (a)(f)(h)1675U0017-7STRUCTURAL FILLERCut7 (a)(f)(h)1675U0017-5EXTERNAL DOUBLERCut (a)(i)1675U0017-7STRUCTURAL FILLERDeburr8 (a)(i)1675U0017-5EXTERNAL DOUBLERDeburr (j)(k)6 OzBMS 5-95SEALANTApply9 Refer to fastener code table. 1675U0017-7STRUCTURAL FILLERInstall (New)10 (j) Refer to fastener code table. 1675U0017-5EXTERNAL DOUBLERInstall (New) (j) (j)(l)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply11 (a) In accordance with drawing 624U4105 sheets 1 and 2. (b) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. (c) Locate the structural filler and the external doubler at stringer S-6 in the correct orientation. Make sure the structural filler and external doubler are flush with the existing skin with the clad surface facing outboard. (d) Back drill from existing fastener locations, and locate and drill new fastener locations. (e) Trim the material edge to maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for new fasteners to maintain 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii will be 0.50 inches minimum unless noted otherwise. FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 3 OF 5) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 17 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 18 More DataQtyIdentificationNameTaskStep (f) It is not required to cut around an existing fastener if it is in contact with the outer edge of the structural filler or external doubler. (g) Trim the material to match the escape hatch door cutout in the existing skin or edge of existing skin. Maintain a 2D minimum edge margin, a 1.7D minimum fastener edge margin is acceptable if limited by adjacent fastener or structure. (h) Trim the radius tangent to adjacent edges to maintain a constant radius of 7 inches minimum. Maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line for new fasteners to maintains a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. (i) Break sharp edges and maintain surface roughness of 125 microinches or better. (j) In accordance with drawing 624U4106 sheets 1 and 2. (k) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (l) Apply aerodynamic sealant along the edges of the external doubler and structural filler. Refer to SOPM 20-50-11 as an accepted procedure. The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4106, Sheets 1 and 2. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode (a)0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (b)(c)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B (b)--BACC30M6COLLAR (a) For 3/16 inch diameter rivets, it is acceptable to adjust the location to maintain a 0.060 inch minimum clearance between rivet head and the edge of adjacent bonded doubler or bonded strap. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 4 OF 5) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 18 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 19 More DataHole DiaQtyIdentificationNameCode (c) Maintain a 2D minimum edge margin, a 1.7D minimum fastener edge margin is acceptable if limited by adjacent fastener or structure. FIGURE 1: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 5 OF 5) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 19 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 20 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1. STA 400 STA 340 AND RETROFIT STA 624U4105 340 SHEET 4 0000000000000 SKIN -- S-2R EXTERNAL DOUBLER RETROFIT 624U4105 SHEET 4 STA 400 - S-6R RETROFIT 624U4105 SHEET 3 STRUCTURAL FILLER RETROFIT E - S-10R 624U4105 SHEET 4 2816099 FIGURE 2: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 1 OF 4) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 20 of 124 ### Page 21 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT RETROFIT STA 624U4106 340 SHEET 5 SKIN - S-2R EXTERNAL DOUBLER ~ RETROFIT SHEET 5 624U4106 H STA 400 - S-6R GI RETROFIT 624U4106 SHEET 4 STRUCTURAL FILLER - S-10R 624U4106 RETROFIT K SHEET 5 FIGURE 2: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 2 OF 4) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 21 of 124 ### Page 22 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4106, Sheets 4 and 5. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)--SKINInspect2 (a)(c)1675U0017-8STRUCTURAL FILLERLocate3 (a)(c)1675U0017-6EXTERNAL DOUBLERLocate (a)(d)-675U0017-8STRUCTURAL FILLERDrill4 (a)(d)-675U0017-6EXTERNAL DOUBLERDrill (a)(e)(f)1675U0017-8STRUCTURAL FILLERCut5 (a)(e)(f)1675U0017-6EXTERNAL DOUBLERCut (a)(f)(g)1675U0017-8STRUCTURAL FILLERCut6 (a)(f)(g)1675U0017-6EXTERNAL DOUBLERCut (a)(h)1675U0017-8STRUCTURAL FILLERDeburr7 (a)(h)1675U0017-6EXTERNAL DOUBLERDeburr (i)(j)6 OzBMS 5-95SEALANTApply8 Refer to fastener code table. 1675U0017-8STRUCTURAL FILLERInstall (New)9 (i) Refer to fastener code table. 1675U0017-6EXTERNAL DOUBLERInstall (New) (i) (i)(k)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply10 (a) In accordance with drawing 624U4105 sheets 3 and 4. (b) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. (c) Locate the structural filler and the external doubler at stringer S-6 in the correct orientation. Make sure the structural filler and external doubler are flush with the existing skin with the clad surface facing outboard. (d) Back drill from existing fastener locations, and locate and drill new fastener locations. (e) Trim the material edge to maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for new fasteners to maintain 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii will be 0.50 inches minimum unless noted otherwise. (f) It is not required to cut around an existing fastener if it is in contact with the outer edge of the structural filler or external doubler. FIGURE 2: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 3 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 22 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 23 More DataQtyIdentificationNameTaskStep (g) Trim the radius tangent to adjacent edges to maintain a constant radius of 7 inches minimum. Maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line for new fasteners to maintains a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. (h) Break sharp edges and maintain surface roughness of 125 microinches or better. (i) In accordance with drawing 624U4106 sheets 4 and 5. (j) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (k) Apply BMS 5-142, Type 2, aerodynamic sealant along the edges of the external doubler and structural filler. Refer to SOPM 20-50-11 as an accepted procedure. The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4106, Sheets 4 and 5. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode (a)0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (b)(c)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B (b)--BACC30M6COLLAR (a) For 3/16 inch diameter rivets, it is acceptable to adjust the location to maintain a 0.060 inch minimum clearance between rivet head and the edge of adjacent bonded doubler or bonded strap. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. (c) Maintain a 2D minimum edge margin, a 1.7D minimum fastener edge margin is acceptable if limited by adjacent fastener or structure. FIGURE 2: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 4 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 23 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 24 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-2. STA 400 STA 000 220 000 0000 | AND G FORWARD STA EXTERNAL AFT EXTERNAL 220 DOUBLER DOUBLER S-231 SPLICE FORWARD PLATE AFT STRUCTURAL STRUCTURAL FILLER FILLER RETROFIT 624U4122 SHEET 1 2819081 FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 1 OF 6) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 24 of 124 ### Page 25 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4122, Sheet 1 and Drawing 624U4123, Sheet 1. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)1861DRAOA SENSORRemove / Keep (a)1233T9131-3GASKETRemove / Keep (a)2-ANGLERemove (a)(c)--SKINInspect2 FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 2 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 25 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 26 More DataQtyIdentificationNameTaskStep (a)(d)1675U0018-17AFT STRUCTURAL FILLER Locate3 (a)(d)1675U0018-13FWD STRUCTURAL FILLER Locate (a)(d)1675U0018-15AFT DOUBLERLocate (a)(d)1675U0018-11FWD DOUBLERLocate (a)(d)1675U0018-19SPLICE PLATELocate (a)(d)2675U0018-21ANGLELocate (a)(e)1675U0018-17AFT STRUCTURAL FILLER Drill4 (a)(e)1675U0018-13FWD STRUCTURAL FILLER Drill (a)(e)1675U0018-15AFT DOUBLERDrill (a)(e)1675U0018-11FWD DOUBLERDrill (a)(e)1675U0018-19SPLICE PLATEDrill (a)(e)2675U0018-21ANGLEDrill (a)(f)1675U0018-17AFT STRUCTURAL FILLER Cut5 (a)(f)1675U0018-13FWD STRUCTURAL FILLER Cut (a)(f)1675U0018-15AFT DOUBLERCut (a)(f)1675U0018-11FWD DOUBLERCut (a)(f)1675U0018-19SPLICE PLATECut (a)(g)1675U0018-11FWD DOUBLERCut6 (a)(h)1675U0018-17AFT STRUCTURAL FILLER Deburr7 (a)(h)1675U0018-13FWD STRUCTURAL FILLER Deburr (a)(h)1675U0018-15AFT DOUBLERDeburr (a)(h)1675U0018-11FWD DOUBLERDeburr (a)(h)1675U0018-19SPLICE PLATEDeburr (a)(h)2675U0018-21ANGLEDeburr FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 3 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 26 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 27 More DataQtyIdentificationNameTaskStep (a)(j)1675U0018-17AFT STRUCTURAL FILLER Cut8 (a)(j)1675U0018-13FWD STRUCTURAL FILLER Cut (i)(k)--FASTENERSCountersink9 (i)(l)6 OzBMS 5-95SEALANTApply10 Refer to fastener code table. 2675U0018-21ANGLEInstall (New)11 (i) Refer to fastener code table. 1675U0018-17AFT STRUCTURAL FILLER Install (New) (i) Refer to fastener code table. 1675U0018-13FWD STRUCTURAL FILLER Install (New) (i) Refer to fastener code table. 1675U0018-15AFT DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-11FWD DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-19SPLICE PLATEInstall (New) (i) (i)(m)1675U0018-22FILLERInstall (New)12 (i)1233T9131-3GASKETInstall (Kept) (i)(n)(o)(p)(q)1861DRAOA SENSORInstall (Kept) (i)(o)8BACB30LH3-5BOLTInstall (New) (i)(r)1861DRAOA SENSORMeasure13 (i)(s)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply14 (a) In accordance with drawing 624U4122 sheet 1. (b) Remove the Angle Of Attack (AOA) sensor. Keep at least two fasteners attached to the tripler for the modification to make sure the tripler does not move. (c) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 4 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 27 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 28 More DataQtyIdentificationNameTaskStep (d) Locate the forward and aft structural fillers, forward and aft external doublers, splice plate and angle at stringer S-23 in the correct orientation. Make sure the forward and aft structural fillers, and forward and aft external doublers are flush with the existing skin with the clad surface facing outboard. (e) Back drill from existing fastener locations, and locate and drill new fastener locations. (f) Trim the material edge, maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for the new fasteners to maintain a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii should be 0.50 inches minimum unless noted otherwise. (g) Trim a circular cutout in the forward external doubler to match the hole for the AOA sensor in the existing skin. (h) Break sharp edges and maintain surface roughness of 125 microinches or better. (i) In accordance with drawing 624U4123 sheet 1. (j) If the edge margin of the existing hole location and edge of structural filler is less than 1.7D, make a cutout in the structural filler and install filler. Break sharp edges and maintain surface roughness of 125 microinches or better. (k) If the fasteners interfere with the forward external doubler, it is acceptable to countersink the fasteners flush with the skin surface. (l) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, splice plate, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (m) Apply chemical conversion coating to holes in filler. Refer to SOPM 20-43-03 as an accepted procedure. (n) Install the AOA sensor under the existing AOA sensor flange. Make sure the two position holes for the AOA sensor in the existing tripler are between 0.2180 - 0.2290 inches, and the holes through the new filler common to the AOA sensor are +/- 0.005 inches with the position holes in the existing tripler. (o) Install 7 countersunk fasteners and measure the resistance from the uninstalled fastener surface to the nearest adjacent skin rivet. Make sure the bonding resistance is 10.00 miliohms maximum. Install the final countersunk fastener. Refer to SWPM 20-20-00 as an accepted procedure. (p) Fill the gap between the forward external doubler and the AOA sensor base with BMS 5-142, TYPE II. Make sure the sealant is flush with the adjacent surfaces. Refer to SOPM 20-50-19 as an accepted pro- cedure. (q) Make sure the surface of the AOA sensor base adjacent to the index holes is flush with the forward external doubler surface. Make sure the AOA sensor base surface is within -0.010 to +0.010 inches of the forward external doubler surface. Apply BMS 5-142, TYPE II, aerodynamic sealant to the forward external doubler to smooth the mismatch of the AOA sensor. Refer to SOPM 20-50-11 as an accepted procedure. (r) Use the AOA sensor base plate and the external skin as contact surfaces to measure the bonding resis- tance. Make sure the bonding resistance is 0.010 ohm or less. Refer to SWPM 20-20-00 as an accepted procedure. (s) Apply BMS 5-142, TYPE II, aerodynamic sealant along the edges of the external doubler, structural filler and splice plate. Refer to SOPM 20-50-11 as an accepted procedure. FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 5 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 28 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 29 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4123, Sheet 1. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode -0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B ---BACC30M6COLLAR (a)(c)0.2630 - 0.2660 -BACB30NW8K( )XBOLT, 100 DEG HEX DR ---BACC30M8COLLAR (a)(b)0.1870 - 0.1900 -BACB30VT6K( )BOLT, PROTRUDING HD C ---BACC30BL6COLLAR (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR D ---BACC30AG6COLLAR (a) If the edge margin of the existing hole location is 1.7D or less, drill a class III hole for 1st oversize. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. (c) If second oversizing is required, bolts can be second oversized to 0.2780 - 0.2810 inch hole diameter. FIGURE 3: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 6 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 29 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 30 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. STA 400 000 STA 220 000000000000 A AND G FORWARD STA 400 AFT EXTERNAL DOUBLER EXTERNAL DOUBLER STA 220 -S-23R SPLICE AFT STRUCTURAL PLATE FORWARD FILLER STRUCTURAL FILLER RETROFIT 624U4122 SHEET 2 FWD 2819099 FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 1 OF 6) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 30 of 124 ### Page 31 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4122, Sheet 2 and Drawing 624U4123, Sheet 2. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)1861DRAOA SENSORRemove / Keep (a)1233T9131-3GASKETRemove / Keep (a)(c)--SKINInspect2 FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 2 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 31 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 32 More DataQtyIdentificationNameTaskStep (a)(d)1675U0018-18AFT STRUCTURAL FILLER Locate3 (a)(d)1675U0018-14FWD STRUCTURAL FILLER Locate (a)(d)1675U0018-16AFT DOUBLERLocate (a)(d)1675U0018-12FWD DOUBLERLocate (a)(d)1675U0018-20SPLICE PLATELocate (a)(e)1675U0018-18AFT STRUCTURAL FILLER Drill4 (a)(e)1675U0018-14FWD STRUCTURAL FILLER Drill (a)(e)1675U0018-16AFT DOUBLERDrill (a)(e)1675U0018-12FWD DOUBLERDrill (a)(e)1675U0018-20SPLICE PLATEDrill (a)(f)1675U0018-18AFT STRUCTURAL FILLER Cut5 (a)(f)1675U0018-14FWD STRUCTURAL FILLER Cut (a)(f)1675U0018-16AFT DOUBLERCut (a)(f)1675U0018-12FWD DOUBLERCut (a)(f)1675U0018-20SPLICE PLATECut (a)(g)1675U0018-12FWD DOUBLERCut6 (a)(h)1675U0018-18AFT STRUCTURAL FILLER Deburr7 (a)(h)1675U0018-14FWD STRUCTURAL FILLER Deburr (a)(h)1675U0018-16AFT DOUBLERDeburr (a)(h)1675U0018-12FWD DOUBLERDeburr (a)(h)1675U0018-20SPLICE PLATEDeburr (a)(j)1675U0018-18AFT STRUCTURAL FILLER Cut8 (a)(j)1675U0018-14FWD STRUCTURAL FILLER Cut (i)(k)--FASTENERSCountersink9 (i)(l)6 OzBMS 5-95SEALANTApply10 FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 3 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 32 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 33 More DataQtyIdentificationNameTaskStep Refer to fastener code table. 1675U0018-18AFT STRUCTURAL FILLER Install (New)11 (i) Refer to fastener code table. 1675U0018-14FWD STRUCTURAL FILLER Install (New) (i) Refer to fastener code table. 1675U0018-16AFT DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-12FWD DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-20SPLICE PLATEInstall (New) (i) (i)(m)1675U0018-22FILLERInstall (New)12 (i)1233T9131-3GASKETInstall (Kept) (i)(n)(o)(p)(q)1861DRAOA SENSORInstall (Kept) (i)(o)8BACB30LH3-5BOLTInstall (New) (i)(r)1861DRAOA SENSORMeasure13 (i)(s)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply14 (a) In accordance with drawing 624U4122 sheet 2. (b) Remove the Angle Of Attack (AOA) sensor. Keep at least two fasteners attached to the tripler for the modification to make sure the tripler does not move. (c) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. (d) Locate the forward and aft structural fillers, forward and aft external doublers, and splice plate at stringer S-23 in the correct orientation. Make sure the forward and aft structural fillers, and forward and aft external doublers are flush with the existing skin with the clad surface facing outboard. (e) Back drill from existing fastener locations, and locate and drill new fastener locations. (f) Trim the material edge, maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for the new fasteners to maintain a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii should be 0.50 inches minimum unless noted otherwise. (g) Trim a circular cutout in the forward external doubler to match the hole for the AOA sensor in the existing skin. FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 4 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 33 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 34 More DataQtyIdentificationNameTaskStep (h) Break sharp edges and maintain surface roughness of 125 microinches or better. (i) In accordance with drawing 624U4123 sheet 2. (j) If the edge margin of the existing hole location and edge of structural filler is less than 1.7D, make a cutout in the structural filler and install filler. Break sharp edges and maintain surface roughness of 125 microinches or better. (k) If the fasteners interfere with the forward external doubler, it is acceptable to countersink the fasteners flush with the skin surface. (l) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, splice plate, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (m) Apply chemical conversion coating to holes in filler. Refer to SOPM 20-43-03 as an accepted procedure. (n) Install the AOA sensor under the existing AOA sensor flange. Make sure the two position holes for the AOA sensor in the existing tripler are between 0.2180 - 0.2290 inches, and the holes through the new filler common to the AOA sensor are +/- 0.005 inches with the position holes in the existing tripler. (o) Install 7 countersunk fasteners and measure the resistance from the uninstalled fastener surface to the nearest adjacent skin rivet. Make sure the bonding resistance is 10.00 milliohms maximum. Install the final countersunk fastener. Refer to SWPM 20-20-00 as an accepted procedure. (p) Fill the gap between the forward external doubler and the AOA sensor base with BMS 5-142, TYPE II. Make sure the sealant is flush with the adjacent surfaces. Refer to SOPM 20-50-19 as an accepted pro- cedure. (q) The surface of the AOA sensor base adjacent to the index holes must be flush with the forward external doubler surface. Make sure the AOA sensor base surface is within + or - 0.010 inches of the forward ex- ternal doubler surface. Apply BMS 5-142, TYPE II, aerodynamic sealant to the forward external doubler to smooth the mismatch of the AOA sensor. Refer to SOPM 20-50-11 as an accepted procedure. (r) Use the AOA sensor base plate and the external skin as contact surfaces to measure the bonding resis- tance. Make sure the bonding resistance is 0.010 ohm or less. Refer to SWPM 20-20-00 as an accepted procedure. (s) Apply BMS 5-142, TYPE II, aerodynamic sealant along the edges of the external doubler, structural filler and splice plate. Refer to SOPM 20-50-11 as an accepted procedure. FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 5 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 34 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 35 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4123, Sheet 2. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode -0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B ---BACC30M6COLLAR (a)(c)0.2630 - 0.2660 -BACB30NW8K( )XBOLT, 100 DEG HEX DR ---BACC30M8COLLAR (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR C --BACC30AG6COLLAR (a) If the edge margin of the existing hole location is 1.7D or less, drill a class III hole for 1st oversize. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. (c) If second oversizing is required, bolts can be second oversized to 0.2780 - 0.2810 inch hole diameter. FIGURE 4: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 6 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 35 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 36 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 2-3. STA 400 STA 340 AND D RETROFIT 624U4105 STA 340 SHEET4 0000000000000 SKIN * S-2R EXTERNAL DOUBLER RETROFIT SHEET 4 624U4105 C STA 400 - S-6R RETROFIT 624U4105 SHEET 10 STRUCTURAL FILLER RETROFIT - S-10R SHEET 4 624U4105 E 2823637 FIGURE 5: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 1 OF 4) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 36 of 124 ### Page 37 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT RETROFIT J STA 624U4106 340 SHEET 12 SKIN - S-2R EXTERNAL DOUBLER ~ RETROFIT 624U4106 SHEET 12L STA 400 - S-6R GI RETROFIT 624U4106 SHEET 11 STRUCTURAL FILLER - S-10R 624U4106 RETROFIT K SHEET 12 FIGURE 5: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 2 OF 4) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 37 of 124 ### Page 38 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4106, Sheets 11 and 12. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)--SKINInspect2 (a)(c)1675U0017-8STRUCTURAL FILLERLocate3 (a)(c)1675U0017-6EXTERNAL DOUBLERLocate (a)(d)-675U0017-8STRUCTURAL FILLERDrill4 (a)(d)-675U0017-6EXTERNAL DOUBLERDrill (a)(e)(f)1675U0017-8STRUCTURAL FILLERCut5 (a)(e)(f)1675U0017-6EXTERNAL DOUBLERCut (a)(f)(g)1675U0017-8STRUCTURAL FILLERCut6 (a)(f)(g)1675U0017-6EXTERNAL DOUBLERCut (a)(h)1675U0017-8STRUCTURAL FILLERDeburr7 (a)(h)1675U0017-6EXTERNAL DOUBLERDeburr (i)(j)6 OzBMS 5-95SEALANTApply8 Refer to fastener code table. 1675U0017-8STRUCTURAL FILLERInstall (New)9 (i) Refer to fastener code table. 1675U0017-6EXTERNAL DOUBLERInstall (New) (i) (i)(k)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply10 (a) In accordance with drawing 624U4105 sheets 10 and 4. (b) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. (c) Locate the structural filler and the external doubler at stringer S-6 in the correct orientation. Make sure the structural filler and external doubler are flush with the existing skin with the clad surface facing outboard. (d) Back drill from existing fastener locations, and locate and drill new fastener locations. (e) Trim the material edge to maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for new fasteners to maintain 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii will be 0.50 inches minimum unless noted otherwise. (f) It is not required to cut around an existing fastener if it is in contact with the outer edge of the structural filler or external doubler. FIGURE 5: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 3 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 38 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 39 More DataQtyIdentificationNameTaskStep (g) Trim the radius tangent to adjacent edges to maintain a constant radius of 7 inches minimum. Maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line for new fasteners to maintains a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. (h) Break sharp edges and maintain surface roughness of 125 microinches or better. (i) In accordance with drawing 624U4106 sheets 11 and 12. (j) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (k) Apply BMS 5-142, TYPE II, aerodynamic sealant along the edges of the external doubler and structural filler. Refer to SOPM 20-50-11 as an accepted procedure. The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4106, Sheets 11 and 12. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode (a)0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (b)(c)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B (b)--BACC30M6COLLAR (a) For 3/16 inch diameter rivets, it is acceptable to adjust the location to maintain a 0.060 inch clearance between rivet head and the edge of adjacent bonded doubler or bonded strap. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. (c) Maintain a 2D minimum edge margin, a 1.7D minimum fastener edge margin is acceptable if limited by adjacent fastener or structure. FIGURE 5: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION RIGHT SIDE (SHEET 4 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 39 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 40 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 3. STA 400 STA 000 220 000 0000 | AND G FORWARD STA EXTERNAL AFT EXTERNAL 220 DOUBLER DOUBLER S-23L SPLICE FORWARD PLATE AFT STRUCTURAL STRUCTURAL FILLER FILLER RETROFIT 624U4122 SHEET 5 2823194 FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 1 OF 6) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished 747-53A2895 RB Work - See page 1 for details. 40 of 124 ### Page 41 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4122, Sheet 5 and Drawing 624U4123, Sheet 5. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)1861DRAOA SENSORRemove / Keep (a)1233T9131-3GASKETRemove / Keep (a)2-ANGLERemove (a)(c)--SKINInspect2 FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 2 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 41 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 42 More DataQtyIdentificationNameTaskStep (a)(d)1675U0018-17AFT STRUCTURAL FILLER Locate3 (a)(d)1675U0018-13FWD STRUCTURAL FILLER Locate (a)(d)1675U0018-15AFT DOUBLERLocate (a)(d)1675U0018-11FWD DOUBLERLocate (a)(d)1675U0018-19SPLICE PLATELocate (a)(d)2675U0018-21ANGLELocate (a)(e)1675U0018-17AFT STRUCTURAL FILLER Drill4 (a)(e)1675U0018-13FWD STRUCTURAL FILLER Drill (a)(e)1675U0018-15AFT DOUBLERDrill (a)(e)1675U0018-11FWD DOUBLERDrill (a)(e)1675U0018-19SPLICE PLATEDrill (a)(e)2675U0018-21ANGLEDrill (a)(f)1675U0018-17AFT STRUCTURAL FILLER Cut5 (a)(f)1675U0018-13FWD STRUCTURAL FILLER Cut (a)(f)1675U0018-15AFT DOUBLERCut (a)(f)1675U0018-11FWD DOUBLERCut (a)(f)1675U0018-19SPLICE PLATECut (a)(g)1675U0018-11FWD DOUBLERCut6 (a)(h)1675U0018-17AFT STRUCTURAL FILLER Deburr7 (a)(h)1675U0018-13FWD STRUCTURAL FILLER Deburr (a)(h)1675U0018-15AFT DOUBLERDeburr (a)(h)1675U0018-11FWD DOUBLERDeburr (a)(h)1675U0018-19SPLICE PLATEDeburr (a)(h)1675U0018-21ANGLEDeburr FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 3 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 42 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 43 More DataQtyIdentificationNameTaskStep (a)(j)1675U0018-17AFT STRUCTURAL FILLER Cut8 (a)(j)1675U0018-13FWD STRUCTURAL FILLER Cut (i)(h)2675U0018-21ANGLECut9 (i)(k)--FASTENERSCountersink10 (i)(l)6 OzBMS 5-95SEALANTApply11 Refer to fastener code table. 2675U0018-21ANGLEInstall (New)12 (i) Refer to fastener code table. 1675U0018-17AFT STRUCTURAL FILLER Install (New) (i) Refer to fastener code table. 1675U0018-13FWD STRUCTURAL FILLER Install (New) (i) Refer to fastener code table. 1675U0018-15AFT DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-11FWD DOUBLERInstall (New) (i) Refer to fastener code table. 1675U0018-19SPLICE PLATEInstall (New) (i) (i)(m)1675U0018-22FILLERInstall (New)13 (i)1233T9131-3GASKETInstall (Kept) (i)(n)(o)(p)(q)1861DRAOA SENSORInstall (Kept) (i)(o)8BACB30LH3-5BOLTInstall (New) (i)(r)1861DRAOA SENSORMeasure14 (i)(s)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply15 (a) In accordance with drawing 624U4122 sheet 5. (b) Remove the Angle Of Attack (AOA) sensor. Keep at least two fasteners attached to the tripler for the modification to make sure the tripler does not move. (c) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 4 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 43 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 44 More DataQtyIdentificationNameTaskStep (d) Locate the forward and aft structural fillers, forward and aft external doublers, splice plate and angle at stringer S-23 in the correct orientation. Make sure the forward and aft structural fillers, and forward and aft external doublers are flush with the existing skin with the clad surface facing outboard. (e) Back drill from existing fastener locations, and locate and drill new fastener locations. (f) Trim the material edge, maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for the new fasteners to maintain a 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii will be 0.50 inches minimum unless noted otherwise. (g) Trim a circular cutout in the forward external doubler to match the hole for the AOA sensor in the existing skin. (h) Break sharp edges and maintain surface roughness of 125 microinches or better. (i) In accordance with drawing 624U4123 sheet 5. (j) If the edge margin of the existing hole location and edge of structural filler is less than 1.7D, make a cutout in the structural filler and install filler. Break sharp edges and maintain surface roughness of 125 microinches or better. (k) If the fasteners interfere with the forward external doubler, it is acceptable to countersink the fasteners flush with the skin surface. (l) Apply BMS 5-95 fay surface sealant to structural filler, external doubler, splice plate, skin and all common surfaces. Refer to SOPM 20-50-19 as an accepted procedure. (m) Apply chemical conversion coating to holes in filler. Refer to SOPM 20-43-03 as an accepted procedure. (n) Install the AOA sensor under the existing AOA sensor flange. Make sure the two position holes for the AOA sensor in the existing tripler are between 0.2180 - 0.2290 inches, and the holes through the new filler common to the AOA sensor are +/- 0.005 inches with the position holes in the existing tripler. (o) Install 7 countersunk fasteners and measure the resistance from the uninstalled fastener surface to the nearest adjacent skin rivet. Make sure the bonding resistance is 10.00 milliohms maximum. Install the final countersunk fastener. Refer to SWPM 20-20-00 as an accepted procedure. (p) Fill the gap between the forward external doubler and the AOA sensor base with BMS 5-142, TYPE II. Make sure the sealant is flush with the adjacent surfaces. Refer to SOPM 20-50-19 as an accepted pro- cedure. (q) Make sure the surface of the AOA sensor base adjacent to the index holes is flush with the forward external doubler surface. Make sure the AOA sensor base surface is within +/ - 0.010 inches of the forward external doubler surface. Apply BMS 5-142, TYPE II, aerodynamic sealant to the forward external doubler to smooth the mismatch of the AOA sensor. Refer to SOPM 20-50-11 as an accepted procedure. (r) Use the AOA sensor base plate and the external skin as contact surfaces to measure the bonding resis- tance. Make sure the bonding resistance is 0.010 ohm or less. Refer to SWPM 20-20-00 as an accepted procedure. (s) Apply BMS 5-142, TYPE II, aerodynamic sealant along the edges of the external doubler, structural filler and splice plate. Refer to SOPM 20-50-11 as an accepted procedure. FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 5 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 44 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 45 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in Drawing 624U4123, Sheet 5. A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the number of fasteners necessary for this figure. More DataHole DiaQtyIdentificationNameCode -0.1900 - 0.1960 -BACR15GF6D( )RIVET, 100 DEGA (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR B ---BACC30M6COLLAR (a)(c)0.2630 - 0.2660 -BACB30NW8K( )XBOLT, 100 DEG HEX DR ---BACC30M8COLLAR (a)(b)0.1870 - 0.1900 -BACB30VT6K( )BOLT, PROTRUDING HD C ---BACC30BL6COLLAR (a)(b)0.2000 - 0.2030 -BACB30NW6K( )XBOLT, 100 DEG HEX DR D --BACC30AG6COLLAR (a) If the edge margin of the existing hole location is 1.7D or less, drill a class III hole for 1st oversize. (b) If second oversizing is required, bolts can be second oversized to 0.2160 - 0.2190 inch hole diameter. (c) If second oversizing is required, bolts can be second oversized to 0.2780 - 0.2810 inch hole diameter. FIGURE 6: SECTION 41 - STRINGER S-23 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 6 OF 6) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 45 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 46 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. STA 400 STA 340 STA 340 1000000 S-2L - 000000 SKIN EXTERNAL DOUBLER STA 400 S-6L STRUCTURAL FILLER S-10L - FWD 2817490 FIGURE 7: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 1 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 46 of 124 ### Page 47 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT STA STA 360 340 - -S-2L -- S-2AL .-- S-3L EXTERNAL (1 DOUBLE -- - S-3AL •- S-4L STA -- S-5L 400 • S-5AL •- S-6L • - S-7L - - S-8L SKIN STRUCTURAL 2 - S-9L FILLER - - S-10L VIEW LOOKING OUTBOARD INSPECTION AREA 2817496 FIGURE 7: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 2 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 47 of 124 ### Page 48 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)--SKINInspect1 (b)--SKINInspect2 (a) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the upper fastener row of the external doubler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. (b) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the lower fastener row of the structural filler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. FIGURE 7: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 48 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 49 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. 400 STA STA 340 STA 340 0000002 SKIN -- S-2R EXTERNAL DOUBLER STA 400 - S-6R STRUCTURAL FILLER - S-10R FWD 2818043 FIGURE 8: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 1 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. DZ11O 6t ### Page 50 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT STA STA 360 340 S-2R- S-2AR-- S-3R -- 1 EXTERNAL S-3AR - - DOUBLER S-4R -- S-5R -- STA 380 STA 400 S-5AR - S-6R-- 222 S-7R S-8R -- • SKIN S-9R- 2) STRUCTURAL FILLER S-10R - штии VIEW LOOKING OUTBOARD INSPECTION AREA 2818042 FIGURE 8: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 2 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 50 of 124 ### Page 51 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)--SKINInspect1 (b)--SKINInspect2 (a) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the upper fastener row of the external doubler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. (b) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the lower fastener row of the structural filler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. FIGURE 8: SECTION 41 - STRINGER S-6 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 51 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 52 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. STA 400 STA 000 220 100000 0000 0000 FORWARD STA 220 DOUBLER EXTERNAL DOUBLER AFT EXTERNAL STA 400 S-23L SPLICE FORWARD PLATE AFT STRUCTURAL STRUCTURAL FILLER FILLER FIGURE 9: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 1 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. ### Page 53 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT FORWARD EXTERNAL DOUBLER STA 280 STRUCTURAL FORWARD FILLER STA 300 VIEW LOOKING OUTBOARD FWD STA 320 STA 340 AFT EXTERNAL DOUBLER STA 360 AFT STRUCTURAL INSPECTION AREA FILLER FIGURE 9: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 2 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 53 of 124 ### Page 54 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)--SKINInspect1 (b)--SKINInspect2 (a) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the upper fastener row of the FWD and AFT external doubler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. (b) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the lower fastener row of the FWD and AFT structural filler attaches to the structure, for any crack in ac- cordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. FIGURE 9: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS LEFT SIDE (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 54 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 55 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 1-3. STA 400 000 STA 220 0000000000000 FORWARD STA AFT EXTERNAL EXTERNAL STA 400 DOUBLER DOUBLER 220 -S-23R SPLICE AFT STRUCTURAL PLATE FORWARD FILLER STRUCTURAL FILLER FWD 2821001 FIGURE 10: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 1 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 55 of 124 ### Page 56 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT AFT EXTERNAL DOUBLER STA 320 STA STA 300 280 FORWARD STRUCTURAL FILLER FWD VIEW LOOKING OUTBOARD FORWARD EXTERNAL DOUBLER STA 260 INSPECTION AREA 40 S-23R 2821214 FIGURE 10: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 2 OF 3) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Copyright © Unpublished Work - See page 1 for details. 56 of 124 ### Page 57 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)--SKINInspect1 (b)--SKINInspect2 (a) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the upper fastener row of the FWD and AFT external doubler attaches to the structure, for any crack in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. (b) Do an internal detailed and surface High Frequency Eddy Current (HFEC) inspection of the skin where the lower fastener row of the FWD and AFT structural filler attaches to the structure, for any crack in ac- cordance with 747 NDT Manual Part 6, 51-00-00, Procedure 4 or 23. Where the skin is covered by a production internal doubler, inspect the internal doubler instead of the skin. It is not necessary to inspect locations where the skin or internal doubler is covered by a frame or tearstrap. FIGURE 10: SECTION 41 - STRINGER S-23 - LAP JOINT - POST-MODIFICATION INSPECTIONS RIGHT SIDE (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 57 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT ### Page 58 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT This Figure applies only to: Group 4-6. STA 400 STA 340 AND RETROFIT STA 340 624U4105 SHEET 2 S-2L - SKIN RETROFIT 624U4105 SHEET 2 EXTERNAL DOUBLER STA 400 S-6L RETROFIT 624U4105 SHEET 1 STRUCTURAL FILLER RETROFIT S-10L - 624U410 SHEET: FWD 2823847 FIGURE 11: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 1 OF 5) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 58 of 124 ### Page 59 (OCR) REQUIREMENTS BULLETIN 747-53A2895 ALERT ALERT RETROFIT STA 340 624U4106 SHEET 14 S-21 SKIN HI RETROFIT 624U4106 SHEET 14 EXTERNAL - DOUBLER STA 400 RETROFIT 624U4106 S-6L - SHEET 13 STRUCTURAL FILLER S-10L - -K RETROFIT 624U4106 SHEET 14 FIGURE 11: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 2 OF 5) Original Issue: September 12, 2019 Export Controlled ECCN: 9E991 747-53A2895 RB Work - See page 1 for details. Copyright © Unpublished 59 of 124 ### Page 60 The step numbers shown below agree with the numbers shown in the circle symbols in Drawing 624U4106, Sheets 13 and 14. The QTY numbers shown below are the number of parts necessary for each figure. More DataQtyIdentificationNameTaskStep (a)--FASTENERSRemove1 (a)(b)--SKINInspect2 (a)(c)1675U0017-7STRUCTURAL FILLERLocate3 (a)(c)1675U0017-5EXTERNAL DOUBLERLocate (a)(d)-675U0017-7STRUCTURAL FILLERDrill4 (a)(d)-675U0017-5EXTERNAL DOUBLERDrill (a)(e)(f)1675U0017-7STRUCTURAL FILLERCut5 (a)(e)(f)1675U0017-5EXTERNAL DOUBLERCut (a)(f)(g)1675U0017-5EXTERNAL DOUBLERCut6 (a)(f)(h)1675U0017-7STRUCTURAL FILLERCut7 (a)(f)(h)1675U0017-5EXTERNAL DOUBLERCut (a)(i)-675U0017-7STRUCTURAL FILLERDeburr8 (a)(i)1675U0017-5EXTERNAL DOUBLERDeburr (j)(k)6 OzBMS 5-95SEALANTApply9 Refer to fastener code table. 1675U0017-7STRUCTURAL FILLERInstall (New)10 (j) Refer to fastener code table. 1675U0017-5EXTERNAL DOUBLERInstall (New) (j) (j)(l)6 OzBMS 5-142, TYPE IIAERODYNAMIC SEALANT Apply11 (a) In accordance with drawing 624U4105 sheets 1 and 2. (b) Do an open hole High Frequency Eddy Current (HFEC) inspection for any crack at hole locations where fasteners were removed, in accordance with 747 NDT Manual Part 6, 51-00-00, Procedure 1, 11, or 16. If any crack is found, contact The Boeing Company for repair instructions and do the repair. (c) Locate the structural filler and the external doubler at Stringer S-6 in the correct orientation. Make sure the structural filler and external doubler are flush with the existing skin with the clad surface facing outboard. (d) Back drill from existing fastener locations, and locate and drill new fastener locations. (e) Trim the material edge to maintain a 2D minimum fastener edge margin for existing fasteners. Make sure the trim line provides enough space for new fasteners to maintain 0.25 inch minimum distance from existing internal doubler edges for clearance of the fastener heads. All internal and external trim radii will be 0.50 inches minimum unless noted otherwise. FIGURE 11: SECTION 41 - STRINGER S-6 - LAP JOINT - MODIFICATION LEFT SIDE (SHEET 3 OF 5) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: September 12, 2019 747-53A2895 RB 60 of 124 REQUIREMENTS BULLETIN 747-53A2895 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/747-53a2895/file/c4b34ec869f7.md?from=61 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.