# Boeing Alert Service Bulletin 747-53A2901: No revision named - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2019-0875, the docket of AD 2020-04-11. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 747-53A2901](https://openairdocs.org/service-documents/boeing/747-53a2901.md) - Title as filed: 747-53A2901-00- RB - Pages: 35 - PDF: https://openairdocs.org/files/sha256/f1/e8/f1e8b3be3b10d1ba0b47afa83262caae4dd0c31a7bb2d1dda193320a1084b132 - Page: https://openairdocs.org/service-documents/boeing/747-53a2901/file/f1e8b3be3b10 ## 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: 747-53A2901 RB Original Issue: July 25, 2019 ATA System: 5311 SUBJECT: FUSELAGE - Skin - Stringer 34L and 40L Lap Splice 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. 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 Unpublished Work.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 Original Issue: July 25, 2019 747-53A2901 RB 1 of 35 5.0 ### Page 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 2 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT BLANK PAGE ### Page 3 Table of Contents 1. EFFECTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 A. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 B. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. CONCURRENT REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. COMPLIANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. APPROVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 A. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 B. Work Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 FIGURE 2: FUSELAGE SKIN - STRINGER 34L LAP SPLICE - HIGH FREQUENCY EDDY CURRENT INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 3 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 4 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 4 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT BLANK PAGE ### Page 5 Commercial Airplanes 747 Requirements Bulletin ALERT Number: 747-53A2901 RB Original Issue: July 25, 2019 ATA System: 5311 SUBJECT: FUSELAGE - Skin - Stringer 34L and 40L Lap Splice Inspection 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 747-400 Airplane(s), line number(s) 717, 739, 748, 760, 769, 777, 791, 805, 809, 812 in 1 Group(s). DESCRIPTIONCONFIGURATIONGROUP 747-400BCF airplanes.-1 B. Spares Affected None. 2. CONCURRENT REQUIREMENTS None. 3. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2008-16-14 is related to this service bulletin. The effective date of AD 2008-16-14 is September 17, 2008. The Federal Aviation Administration (FAA) will possibly release an additional Airworthiness Directive related to Boeing Requirements Bulletin 747-53A2901 RB. The Airworthiness Directive will make the compliance tasks and times given in Boeing Requirements Bulletin 747-53A2901 RB mandatory. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 5 of 35 ### Page 6 Accomplish the required action(s), based on the applicable condition(s) in Table 1 and Table 2, 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. Table 1: Low Frequency Eddy Current (LFEC) Inspections of the Fuselage Upper Skin Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 1,500 flight cycles af- ter the Original Issue date of the Require- ments Bulletin 747-53A2901 RB. Before 11,000 total flight cy- cles. Do a LFEC inspection of the fuselage upper skin at Stringer (S) 40L lap splice, from Station (STA) 1640 to STA 1820 for any crack. All airplanes -Before further flight.ACTION 1:CONDITION 1: Contact The Boeing Company for repair in- structions and do the re- pair. ANY CRACK FOUND. 1,500 flight cycles.-ACTION 2: Repeat the LFEC inspec- tion of the fuselage upper skin at S-40L lap splice, from STA 1640 to STA 1820 for any crack. (a) 1,500 flight cycles.-Repeat the LFEC inspec- tion of the fuselage upper skin at S-40L lap splice, from STA 1640 to STA 1820 for any crack. (a) CONDITION 2: NO CRACK FOUND. (a) It is not required to do the inspections in accordance with Requirements Bulletin 747-53A2901 RB in areas where a repair covers the affected inspection area and meets the following conditions: 1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 747- 53A2901 RB and installed after the Original Issue date of the Requirements Bulletin 747- 53A2901 RB. 2. The repair was approved by the Boeing Organization Designation Authorization (ODA) via an FAA Form 8100-9 which contains a repeat inspection program for the subject area. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 6 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 7 Table 2: High Frequency Eddy Current (HFEC) Inspections of the Fuselage Upper Skin Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 1,500 flight cycles af- ter the Original Issue date of the Require- ments Bulletin 747-53A2901 RB. Before 11,000 total flight cy- cles. Do a HFEC inspection of the fuselage upper skin at Stringer (S) 34L lap splice, from Station (STA) 1640 to STA 1820 for any crack. All airplanes -Before further flight.ACTION 1:CONDITION 3: Contact The Boeing Company for repair in- structions and do the re- pair. ANY CRACK FOUND. 3,000 flight cycles.-ACTION 2: Repeat the HFEC inspec- tion of the fuselage upper skin at S-34L lap splice, from STA 1640 to STA 1820 for any crack. (a) 3,000 flight cycles.-Repeat the HFEC inspec- tion of the fuselage upper skin at S-34L lap splice, from STA 1640 to STA 1820 for any crack. (a) CONDITION 4: NO CRACK FOUND. (a) It is not required to do the inspections in accordance with Requirements Bulletin 747-53A2901 RB in areas where a repair covers the affected inspection area and meets the following conditions: 1. The repair is the corrective action to the crack condition identified in the Requirements Bulletin 747- 53A2901 RB and installed after the Original Issue date of the Requirements Bulletin 747- 53A2901 RB. 2. The repair was approved by the Boeing Organization Designation Authorization (ODA) via an FAA Form 8100-9 which contains a repeat inspection program for the subject area. 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: July 25, 2019 747-53A2901 RB 7 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 8 In addition, the Manager of the Seattle Aircraft Certification Office (ACO) Branch approves the accomplishment of the inspection and repair actions with corresponding compliance times specified in Tables 1 and 2 under paragraph 1.E., "Compliance," of this Requirements Bulletin (RB), as an Alternate Method of Compliance (AMOC) to the accomplishment of the corresponding inspection and repair requirements of AD 2008-16-14. This AMOC is only applicable after the accomplishment of the initial inspections specified in Paragraph 1.E., "Compliance" of this RB. All provisions of AD 2008-16-14 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 8 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 9 5. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION NOTE: 1. This is an Enhanced Required for Compliance document. There will 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 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. 3. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance. 4. 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. 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: July 25, 2019 747-53A2901 RB 9 of 35 REQUIREMENTS BULLETIN 747-53A2901 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. 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. 8. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 9. 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. B. WORK INSTRUCTIONS Actions Required for Compliance 1. Requirements. Table 1: Low Frequency Eddy Current (LFEC) Inspections of the Fuselage Upper Skin Refer to the listed procedures in SB 747-53A2901 Origi- nal Issue or later approved revi- sions as an accept- ed procedure Method of ComplianceActionCondition DO PART 1:-Do a LFEC inspection of the fuselage upper skin at Stringer (S) 40L lap splice, from Station (STA) 1640 to STA 1820 for any crack. All airplanes GET ACCESS -FIGURE 1 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 10 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 11 Table 1: Low Frequency Eddy Current (LFEC) Inspections of the Fuselage Upper Skin Refer to the listed procedures in SB 747-53A2901 Origi- nal Issue or later approved revi- sions as an accept- ed procedure Method of ComplianceActionCondition DO PART 2:-ACTION 1:CONDITION 1: CLOSE ACCESSContact The Boeing Company for repair instructions and do the repair. ANY CRACK FOUND. DO PART 1:-ACTION 2: GET ACCESSRepeat the LFEC inspection of the fuselage upper skin at S-40L lap splice, from STA 1640 to STA 1820 for any crack. (a) -FIGURE 1 DO PART 2:- CLOSE ACCESS DO PART 1:-Repeat the LFEC inspection of the fuselage upper skin at S-40L lap splice, from STA 1640 to STA 1820 for any crack. (a) CONDITION 2: NO CRACK FOUND. GET ACCESS -FIGURE 1 DO PART 2:- CLOSE ACCESS (a) It is not required to do the inspections in accordance with Requirements Bulletin 747-53A2901 RB in areas where a repair covers the affected inspection area and meets the following conditions: 1. The repair is the corrective action to the crack condition identified in the Requirements Bulletin 747- 53A2901 RB and installed after the Original Issue date of the Requirements Bulletin 747- 53A2901 RB. 2. The repair was approved by the Boeing Organization Designation Authorization (ODA) via an FAA Form 8100-9 which contains a repeat inspection program for the subject area. Table 2: High Frequency Eddy Current (HFEC) Inspections of the Fuselage Upper Skin Refer to the listed procedures in SB 747-53A2901 Origi- nal Issue or later approved revi- sions as an accept- ed procedure Method of ComplianceActionCondition DO PART 1:-Do a HFEC inspection of the fuselage upper skin at Stringer (S) 34L lap splice, from Station (STA) 1640 to STA 1820 for any crack. All airplanes GET ACCESS -FIGURE 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 11 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 12 Table 2: High Frequency Eddy Current (HFEC) Inspections of the Fuselage Upper Skin Refer to the listed procedures in SB 747-53A2901 Origi- nal Issue or later approved revi- sions as an accept- ed procedure Method of ComplianceActionCondition DO PART 2:-ACTION 1:CONDITION 3: CLOSE ACCESSContact The Boeing Company for repair instructions and do the repair. ANY CRACK FOUND. DO PART 1:-ACTION 2: GET ACCESSRepeat the HFEC inspection of the fuselage upper skin at S-34L lap splice, from STA 1640 to STA 1820 for any crack. (a) -FIGURE 2 DO PART 2:- CLOSE ACCESS DO PART 1:-Repeat the HFEC inspection of the fuselage upper skin at S-34L lap splice, from STA 1640 to STA 1820 for any crack. (a) CONDITION 4: NO CRACK FOUND. GET ACCESS -FIGURE 2 DO PART 2:- CLOSE ACCESS (a) It is not required to do the inspections in accordance with Requirements Bulletin 747-53A2901 RB in areas where a repair covers the affected inspection area and meets the following conditions: 1. The repair is the corrective action to the crack condition identified in the Requirements Bulletin 747- 53A2901 RB and installed after the Original Issue date of the Requirements Bulletin 747- 53A2901 RB. 2. The repair was approved by the Boeing Organization Designation Authorization (ODA) via an FAA Form 8100-9 which contains a repeat inspection program for the subject area. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 12 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 13 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT STA 1640 STA 1820 STA 1740+1 STA STA STA STAO STA $780 STA UPPER 1640 1660 1680 1760 1820 SKIN S-34L S-40L - LOWER SKIN EXTERNAL DOUBLER FWD 2869471 FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 1 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 13 of 35 ### Page 14 (OCR) + ** ** *+ *i + ..... 798-S + + NINS 748-S 788-S 768-S 70₺-S *************** ***************** VIS VIS ам- 0991 2869472 ### Page 15 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN S-34L * + + * * S-35L ******* **+* EXTERNAL ‚DOUBLER - 79€-S **** * * * * - 728-S - 788-S * +* - 768-S ******* S-40L ****** * * ** ******************* STA VIEW LOOKING INBOARD STA FWD 1660 1680 2869475 INSPECTION AREA FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 3 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 15 of 35 ### Page 16 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN 7 + 7 7 S-34L ****** * * ****** ÷ S-35L * * ***** EXTERNAL ‚DOUBLER S-36L ********** * * + S-37L + S-38L + S-39L S-40L ********************* ******************* STA VIEW LOOKING INBOARD STA FWD 1680 1700 2869486 INSPECTION AREA FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 4 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 16 of 35 ### Page 17 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN S-34L * * " * * * *7 ******* * * S-35L - * * * * * EXTERNAL ‚DOUBLER S-36L - + % S-37L S-38L ' S-39L - ++ S-40L **************** ****************** STA VIEW LOOKING INBOARD STA FWD 1700 1720 2869497 INSPECTION AREA FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 5 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 17 of 35 ### Page 18 (OCR) * + ..... + + 798-9 ........ TENTEE + ************ + ÷ ********* 788-S ******** TENDEN + + + 768-S ........ *+* 70₺-S ****** ****** *********************** VIS VIS VIS OZLI 1+OTLI O+LI 2869504 ### Page 19 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN ·/77 S-34L * *+ * + * * * + * S-35L EXTERNAL DOUBLER S-36L * * * S-37L - INTERNAL STRAP S-38L - S-39L S-40L *********** ******* * + + STA STA VIEW LOOKING INBOARD STA INSPECTION AREA 1740 1740+1 1760 2869511 FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 7 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 19 of 35 ### Page 20 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN S-34L *+*+++++ * * * * **** + S-35L * ........* EXTERNAL DOUBLER + S-36L ********* S-37L ******** + + S-38L - ****** * * + S-39L * * S-40L 1*****+ ********* * * ******* STA VIEW LOOKING INBOARD STA 1760 1780 2869515 INSPECTION AREA FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 8 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 20 of 35 ### Page 21 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN 777777 S-34L *+**+* * * * * ** S-35L - EXTERNAL ‚DOUBLER • 798-S * **** + _ 728-S * * * • 788-S - 768-S S-40L ************** *********** STA VIEW LOOKING INBOARD STA -WD 1780 1800 2869520 INSPECTION AREA FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 9 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 21 of 35 ### Page 22 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT UPPER SKIN S-34L - ***** + * S-35L • * * EXTERNAL DOUBLER S-36L **** 'LOWER SKIN S-37L * * * * S-38L S-39L - + % S-40L ****** INSPECTION AREA 1800 STA VIEW LOOKING INBOARD 1820 STA 2896987 FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 10 OF 11) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 22 of 35 ### Page 23 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTYnumbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)-STRINGER S-40LUPPER SKINInspect1 (a) Do a Low Frequency Eddy Current (LFEC) inspection of the fuselage upper skin at the S-40L lap splice, from STA 1640 to STA 1820 for any crack. Inspect along the fastener row in accordance with 747 NDT Manual D6-7170, Part 6, 53-30-00, Procedure 5. FIGURE 1: FUSELAGE SKIN - STRINGER 40L LAP SPLICE - LOW FREQUENCY EDDY CURRENT INSPECTION (SHEET 11 OF 11) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 23 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT ### Page 24 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT STA 1640 STA 1820 STA 1740+1 STA STA STA STA STA STA UPPER 1640 1660 1680 1700 1740 176 1820 SKIN S S-40L LOWER SKIN EXTERNAL DOUBLER 2869007 FIGURE 2: FUSELAGE SKIN - STRINGER 34L LAP SPLICE - HIGH FREQUENCY EDDY CURRENT INSPECTION (SHEET 1 OF 12) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 24 of 35 ### Page 25 (OCR) VIS 0991 VANA * * * * ******* ********** + * 798-S * + * ** NIXS 768- * * ****************** 70₺-S ******************** ********** 2869043 ### Page 26 (OCR) VIS 0991 0891 * ÷У· ********** ****************** ***** 798-S . . + + . 798-S *********** - 728-S ******* - 788-S +*+* - 768-S * * * ***************] 70+-S ******************** ********* 2869213 ### Page 27 (OCR) VIS VIS 0891 OOLL ·#/##: TE-S ****** ***** + ++ *+*+* ********* + • 798-S + + + * * * . 798-S * * ********* *** 748-S 788-S - 768-S ************** 70t-S ********************* * * * ********** 2869225 ### Page 28 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT STA STA 1700 1 UPPER SKIN 1720 S-34L ********** **** ********** ********** + S-35L * * * + * EXTERNAL DOUBLER S-36L - ***** ****** S-37L * ** * * S-38L S-39L - ** * * ************** * * * * . . . S-40L ******************* VIEW LOOKING INBOARD -WD INSPECTION AREA 2869230 FIGURE 2: FUSELAGE SKIN - STRINGER 34L LAP SPLICE - HIGH FREQUENCY EDDY CURRENT INSPECTION (SHEET 5 OF 12) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 28 of 35 ### Page 29 (OCR) VIS VIS OZLI WAYWA: : :::/#VH - E-S *****+ * + *.*** * * ****** ******** **'*** * *+ * * * * * + . 798-S 798-S ******************* + + 7L8-S + + - 788-S + + 768-S *************** 70+-S ****************** ************** 2869372 (T CO COA) ### Page 30 (OCR) VIS VIS VIS 0921 * + *+* +*++ + + + **++** ******* *************** ** * * 798-S + + - 798-S +*+ ***** TE-S 78&-S • 768-S ****************** 70+-S * * * * * * * * * * * * ** *'****" ************* ам- 2869389 ### Page 31 (OCR) THETY VIS VIS 0921 08L1 VAL*A* ****** *+ + ****** * * ******************* 798-S - 798-S * * * **** - 728-S * * - 788-S + - 768-S ************** 70+-S ****************** * * *********** 2869391 COLONI 90 18 ### Page 32 (OCR) AYETE VIS VIS 08L1 NYS H ddn OÙ 0081 TE-S ******** + + * + + ******* ******* * ** + 798-S * + TENERE 798-S **** 748-S **+*** 788-S 768-S . . *****!!*******!** 70₺-S ***************** ************* ам- COE COONE 2869405 (A JO ENS) SEO LE ### Page 33 (OCR) PEETV VIS VIS 008 1 /AWÁ: : - TE-S * + + + ****** ******** 79g-S * + TENDEE - 798-S ***** NINS - 748-S * * * * * * + - 788-S + * * + - 76&-S * + + * + ****************** 70₺-S ******************** ********************* 01980 (AL O OL EENS) ### Page 34 (OCR) REQUIREMENTS BULLETIN 747-53A2901 ALERT ALERT DUPERSKIN S-34L EXTERNAL DOUBLER LOWER SKIN VIEW LOOKING AFT INBD INSPECTION AREA A-A 2869416 FIGURE 2: FUSELAGE SKIN - STRINGER 34L LAP SPLICE - HIGH FREQUENCY EDDY CURRENT INSPECTION (SHEET 11 OF 12) Original Issue: July 25, 2019 Export Controlled ECCN: 9E991 747-53A2901 RB Copyright © Unpublished Work - See page 1 for details. 34 of 35 ### Page 35 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)-STRINGER S-34LUPPER SKINInspect1 (a) Do a High Frequency Eddy Current (HFEC) inspection of the fuselage upper skin at the S-34L lap splice, from STA 1640 to STA 1820 for any crack. Inspect along the fastener row in accordance with 747 NDT Manual D6-7170, Part 6, 51-00-00, Procedure 23. FIGURE 2: FUSELAGE SKIN - STRINGER 34L LAP SPLICE - HIGH FREQUENCY EDDY CURRENT INSPECTION (SHEET 12 OF 12) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2019 747-53A2901 RB 35 of 35 REQUIREMENTS BULLETIN 747-53A2901 ALERTALERT --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. 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