# Boeing Alert Requirements Bulletin 737-57A1353 RB: No revision named - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2022-1061; AD 2022-25-15 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Requirements Bulletin 737-57A1353 RB](https://openairdocs.org/service-documents/boeing/737-57a1353-rb.md) - Title as filed: 737-57A1353 RB - Pages: 57 - PDF: https://openairdocs.org/files/sha256/0d/ba/0dbae6cc0d1c8b5ea6ce3a2bcc01d2e639ce3fa42329709aaef16f464541b573 - Page: https://openairdocs.org/service-documents/boeing/737-57a1353-rb/file/0dbae6cc0d1c ## 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 737 Requirements Bulletin ALERT Number: 737-57A1353 RB Original Issue: February 10, 2022 ATA System: 5711 SUBJECT: WINGS - Wing Spar - Wing Rear Spar Lower Chord Inspection EXPORT CONTROLLED - This technology or software is subject to the U.S. Export Administration Regulations (EAR), (15 C.F.R. Parts 730-774). No authorization from the U.S. Department of Commerce is required for export, re-export, in-country transfer, or access EXCEPT to country group E:1 or E:2 countries/persons per Supp.1 to Part 740 of the EAR. 9E991ECCN: Copyright © 2022 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 Unpublished Work.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 Original Issue: February 10, 2022 737-57A1353 RB 1 of 57 3.0 ### Page 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 2 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT BLANK PAGE ### Page 3 Table of Contents 1. EFFECTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 A. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 B. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2. CONCURRENT REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3. COMPLIANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. APPROVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 A. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Work Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 FIGURE 3: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION [Group 2-3] . . . . . . . . . 22 FIGURE 4: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION [Group 2-3] . . . . . . . . . 24 FIGURE 5: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 2, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURE 6: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 2, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . 30 FIGURE 7: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 2, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . 34 FIGURE 8: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 2, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . 37 FIGURE 9: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 3, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . 40 FIGURE 10: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 3, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . 43 FIGURE 11: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 3, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 12: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION [Group 3, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . 49 FIGURE 13: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION [Group 2-3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 FIGURE 14: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION [Group 2-3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 3 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 4 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 4 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT BLANK PAGE ### Page 5 Commercial Airplanes 737 Requirements Bulletin ALERT Number: 737-57A1353 RB Original Issue: February 10, 2022 ATA System: 5711 SUBJECT: WINGS - Wing Spar - Wing Rear Spar Lower Chord 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 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 Airplane(s), line number(s) 1-3132 in 3 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 Numbers and Group Information for the applicable airplanes is given below. DESCRIPTIONCONFIGURATIONGROUP 737-100/-200/-200C Airplanes, line numbers 1-291-1 737-200/-200C Airplanes-2 737-200/-200C Airplanes that have not been modified in accordance with Service Bulletin 737-57-1216 1 737-200/-200C Airplanes that have been modified in accordance with Service Bulletin 737-57-1216 2 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 5 of 57 ### Page 6 DESCRIPTIONCONFIGURATIONGROUP 737-300/-400/-500 Airplanes-3 737-300/-400/-500 Airplanes that have not been modified in accordance with Service Bulletin 737-57-1216 1 737-300/-400/-500 Airplanes that have been modified in accordance with Service Bulletin 737-57-1216 2 Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 GroupVariable Number 1PA001 - PA022 1PA099 1PA231 - PA232 1PC001 - PC005 1PG001 - PG075 1PG199 1PG201 - PG230 1PG251 - PG255 1PG271 - PG279 1PG301 - PG314 1PG331 - PG332 1PG351 - PG356 1PG375 1PG401 - PG403 1PG431 - PG442 1PG471 - PG475 1PG501 - PG505 1PG571 - PG583 2PG584 - PG586 1PG621 - PG630 1PG651 - PG652 1PG701 - PG705 GroupVariable Number 2PH001 2PH011 - PH013 2PH021 - PH024 1PH701 - PH715 1PH731 - PH732 1PH741 - PH742 2PH743 1PJ001 - PJ002 2PJ003 - PJ009 1PJ031 - PJ032 1PJ071 - PJ072 1PJ101 - PJ104 2PJ105 - PJ119 2PJ201 - PJ219 3PJ301 - PJ302 3PJ551 - PJ561 3PJ601 - PJ615 3PJ811 3PJ816 - PJ817 2PK026 - PK029 2PK041 - PK053 2PK061 - PK070 GroupVariable Number 2PK081 - PK082 2PK091 - PK099 2PK101 - PK103 2PK111 - PK120 2PK141 - PK146 2PK201 - PK204 2PK211 - PK223 2PK231 - PK241 2PK251 - PK258 2PK271 - PK274 2PK281 - PK289 2PK291 2PK301 - PK318 2PK341 2PK351 - PK361 2PK391 2PK431 - PK433 2PK451 - PK452 2PK461 - PK469 2PK495 2PK501 - PK504 2PK511 - PK515 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 6 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 7 GroupVariable Number 2PK519 2PK521 - PK528 2PK541 - PK565 2PK581 2PK591 - PK599 2PK601 - PK617 2PK621 - PK637 2PK641 - PK642 2PK661 - PK666 2PK671 - PK681 2PK691 - PK697 2PK711 - PK716 2PK731 - PK765 2PK771 - PK779 2PK801 - PK804 2PK819 - PK827 2PK830 2PK861 - PK863 2PK871 - PK874 2PK881 - PK884 2PK901 - PK938 2PK971 - PK974 2PL001 - PL028 2PL061 2PL081 2PL101 - PL113 2PL151 2PL171 - PL172 2PL201 - PL203 2PL221 2PL401 - PL417 2PL421 2PL441 GroupVariable Number 2PL451 - PL456 2PL471 2PL491 2PL501 - PL506 2PL551 - PL562 2PL581 2PL601 - PL603 2PL611 2PL621 - PL626 2PL631 - PL632 1PL711 - PL712 1PL716 2PL717 - PL747 2PL756 2PL758 2PL761 - PL770 2PL781 - PL788 2PL793 1PL801 - PL803 2PM001 - PM006 2PM016 - PM017 2PM021 - PM023 2PM051 - PM066 2PM101 - PM119 2PM141 - PM142 2PM171 2PM181 2PM251 - PM255 2PM281 - PM283 3PM381 - PM399 3PM401 - PM417 3PM541 - PM564 2PN001 - PN002 GroupVariable Number 2PN021 - PN043 2PN081 - PN086 2PN101 - PN117 2PN131 - PN163 2PN401 - PN420 2PN431 - PN433 2PN451 - PN456 2PN471 - PN474 2PN481 2PN491 - PN493 2PN501 - PN502 2PN511 - PN512 2PN521 3PP001 - PP054 3PP101 - PP169 3PP181 - PP199 3PP201 - PP205 3PP221 3PP231 - PP243 3PP281 - PP286 3PP301 - PP305 3PP351 - PP353 3PP376 - PP384 3PP391 - PP393 3PP401 - PP440 3PP471 - PP475 3PP501 - PP522 3PP631 - PP634 3PP651 - PP652 3PP671 - PP699 3PP701 - PP733 3PP771 - PP779 3PP801 - PP808 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 7 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 8 GroupVariable Number 3PP821 - PP827 3PP831 - PP848 3PP851 - PP852 3PP861 - PP877 3PP891 - PP899 3PP901 - PP936 3PP946 - PP948 3PP951 - PP952 3PP961 - PP967 3PP981 - PP991 3PP993 3PQ001 - PQ016 3PQ026 - PQ041 3PQ051 - PQ092 3PQ101 - PQ199 3PQ201 - PQ202 3PQ221 - PQ237 3PQ241 - PQ243 3PQ251 - PQ267 3PQ281 - PQ299 3PQ301 - PQ307 3PQ331 - PQ332 3PQ341 - PQ348 3PQ361 - PQ373 3PQ391 - PQ395 3PQ401 - PQ418 3PQ421 3PQ431 - PQ438 3PQ447 - PQ448 3PQ451 3PQ454 3PQ471 - PQ475 3PQ479 - PQ481 GroupVariable Number 3PQ486 - PQ487 3PQ491 - PQ493 3PQ771 - PQ772 3PQ791 - PQ793 3PQ801 - PQ805 3PQ931 - PQ935 3PQ951 3PQ971 - PQ997 3PR001 - PR017 3PR021 - PR034 3PR041 - PR045 3PR061 - PR072 3PR077 - PR082 3PR091 - PR092 3PR096 3PR101 3PR121 - PR122 3PR131 - PR132 3PR141 - PR143 3PR161 - PR172 3PR181 3PS601 - PS631 3PS636 - PS638 3PS641 - PS644 3PS651 - PS657 3PS666 - PS669 3PS691 - PS692 3PS701 - PS706 3PS751 - PS799 3PS811 3PS836 - PS837 3PS841 - PS846 3PS851 - PS852 GroupVariable Number 3PS856 3PS861 - PS863 3PS866 - PS868 3PS871 - PS874 3PS896 - PS897 3PS901 - PS941 3PS956 - PS957 3PS961 - PS963 3PS971 - PS978 3PT001 - PT015 3PT021 - PT031 3PT041 - PT064 3PT101 - PT105 3PT121 - PT138 3PT146 - PT148 3PT161 - PT170 3PT181 - PT188 3PT211 - PT220 3PT295 3PT301 - PT309 3PT331 - PT360 3PT381 - PT399 3PT401 - PT438 3PT501 - PT517 3PT561 - PT565 3PT581 - PT586 3PT611 - PT621 3PT641 - PT644 3PT651 - PT656 3PT671 - PT672 3PT681 - PT685 3PT701 - PT703 3PT716 - PT717 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 8 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 9 GroupVariable Number 3PT721 - PT725 3PT801 - PT834 3PT851 - PT854 3PT871 - PT886 3PT901 - PT930 3PT971 - PT973 3PT981 - PT985 3PT996 3PU001 - PU025 3PU301 3PU311 - PU313 3PV001 - PV055 3PV201 - PV209 3PV226 - PV229 3PV231 - PV237 3PV271 - PV272 3PV281 - PV287 3PV296 3PV301 - PV302 3PV351 3PV356 - PV357 3PW001 - PW054 3PW061 - PW068 3PW072 3PW086 - PW088 3PW091 - PW094 3PW101 - PW102 3PW106 3PW111 - PW120 3PW156 - PW157 3PW161 - PW171 3PW201 - PW252 3PW261 - PW268 GroupVariable Number 3PW271 - PW276 3PW278 3PW281 - PW293 3PW296 3PW301 - PW327 3PW401 - PW408 3PW411 - PW418 3PW421 - PW424 3PW431 - PW435 3PW441 - PW450 3PW461 - PW467 3PW501 - PW504 3PW511 - PW522 3PW524 - PW550 3PW556 - PW557 3PW561 - PW564 3PW571 - PW576 3PW591 - PW596 3PW611 - PW622 3PW631 - PW637 3PW661 - PW662 3PW681 - PW683 3PW701 - PW702 3PW711 - PW717 3PW741 - PW742 3PW761 3PW771 3PW831 3PW851 - PW856 1PX071 1PX701 1PY001 - PY008 1PY021 GroupVariable Number 2PY022 1PY031 2PY036 - PY037 2PY046 - PY048 2PY051 - PY053 2PY056 - PY057 2PY101 - PY103 2PY111 - PY113 2PY131 - PY135 2PY141 - PY143 2PY151 - PY154 2PY156 - PY157 2PY161 - PY162 2PY166 2PY191 2PY201 2PY221 - PY222 2PY231 2PY241 - PY244 2PY270 - PY275 2PY281 2PY286 1PY301 - PY304 1PY321 - PY323 1PY341 - PY346 1PY361 - PY362 1PY381 2PY401 2PY409 - PY411 2PY421 - PY422 2PY441 2PY451 2PY461 - PY463 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 9 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 10 GroupVariable Number 2PY591 - PY595 2PY611 - PY612 2PY621 GroupVariable Number 2PY631 2PY651 2PY671 - PY672 GroupVariable Number 2PY721 2PY741 -- 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 737-57A1353 RB. The Airworthiness Directive will make the compliance tasks and times given in Requirements Bulletin 737-57A1353 RB mandatory. Accomplish the required actions, based on the applicable conditions in Table 1, in accordance with 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: Boeing endorses the FAA rules related to Limit of Validity (LOV) and recommends immediate and permanent removal from service of any airplanes upon reaching the LOV, whether or not it is operated under FAA jurisdiction. As such, Boeing no longer provides maintenance instructions for airplanes that have accumulated flight cycles beyond the LOV. Airplanes in Group 1 (line numbers 1-291) have accumulated flight cycles beyond the LOV of the maintenance program. 14 CFR 121.1115 and 129.115 prohibit operation of an airplane beyond its LOV. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 10 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 11 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Repeat Interval (Not to Exceed) Boeing Recommended Compliance Time (Whichever Occurs Later) ActionCondition -Within 4,500 flight cycles af- ter the Original Issue date of Requirements Bulletin 737- 57A1353 RB. Before 50,000 Total Flight Cy- cles. OPTION 1: Do an open hole High Frequency Eddy Current (HFEC) inspection of the wing rear spar lower chord at the Main Landing Gear (MLG) aft fitting at Wing Buttock Line (WBL) 157 for any crack. All Airplanes. OPTION 2: Do a surface HFEC inspection and ultrasonic (UT) inspection of the wing rear spar lower chord at the MLG aft fit- ting at WBL 157 for any crack. -Before further flight.CONDITION 1 (ACTION 1): Contact The Boeing Company for repair instructions and do the repair. CONDITION 1: ANY CRACK FOUND DURING OPTION 1 OPEN HOLE HFEC INSPECTION. -Before further flight.CONDITION 1 (ACTION 2): In- stall fasteners. 24,000 flight cy- cles. -CONDITION 1 (ACTION 3) (OPTION 1): Repeat open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) -Within 24,000 flight cycles after most recent OPTION 1 open hole HFEC inspection. CONDITION 1 (ACTION 3) (OPTION 2) Do a surface HFEC inspection and UT inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 11 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 12 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Repeat Interval (Not to Exceed) Boeing Recommended Compliance Time (Whichever Occurs Later) ActionCondition -Before further flight.CONDITION 2: (ACTION 1): In- stall fasteners. CONDITION 2: NO CRACK FOUND DURING OPTION 1 OPEN HOLE HFEC INSPECTION. 24,000 flight cy- cles. -CONDITION 2 (ACTION 2) (OPTION 1): Repeat open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) -Within 24,000 flight cycles after most recent OPTION 1 open hole HFEC inspection. CONDITION 2 (ACTION 2) (OPTION 2): Do a surface HFEC inspection and UT inspec- tion of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) -Before further flight.CONDITION 3 (ACTION 1): Contact The Boeing Company for repair instructions and do the repair. CONDITION 3: ANY CRACK FOUND DURING OPTION 2 SURFACE HFEC AND UT INSPEC- TION. -Within 9,000 flight cycles aftermost recent OPTION 2 surface HFEC and UT inspections. CONDITION 3 (ACTION 2) (OPTION 1): Do an open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) 9,000 flight cycles.-CONDITION 3 (ACTION 2) (OPTION 2): Repeat surface HFEC inspection and UT inspec- tion of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 12 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 13 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Repeat Interval (Not to Exceed) Boeing Recommended Compliance Time (Whichever Occurs Later) ActionCondition -Within 9,000 flight cycles after most recent OPTION 2 surface HFEC and UT inspections. CONDITION 4 (OPTION 1): Do an open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) CONDITION 4: NO CRACK FOUND DURING OPTION 2 SURFACE HFEC AND UT INSPEC- TION. 9,000 flight cycles.-CONDITION 4 (OPTION 2): Repeat surface HFEC inspec- tion and UT inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) (a) After the accomplishment of this OPTION, it is acceptable to change the repeat action from this OPTION to any other OPTION under this CONDITION. (b) It is not required to do the inspection in areas where a repair covers the affected inspection area if the repairs meets the conditions that follow: 1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737- 57A1353 RB and installed after the original issue date of Requirements Bulletin 737-57A1353 RB. 2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA) via a FAA Form 8100-9. 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 Union Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in this Requirements 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. These data have been reviewed by the Boeing ODA for fuel tank ignition prevention requirements, and no further approval from the FAA Oversight Office is required to satisfy the requirements of CDCCL 28-AWL-11 provided the repair or alteration is accomplished in accordance with these instructions. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 13 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 14 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT BLANK PAGE ### Page 15 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 737-SL-51-042, 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 737 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 737 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 737 Aircraft Maintenance Manual (AMM). Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 15 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 16 — 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 part, 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 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. 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. 10. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification 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. 11. Use the approved process and material substitutions, except for fasteners, in accordance with SRM Chapter 51. B. WORK INSTRUCTIONS Actions Required for Compliance 1. Requirements. Group 1: Boeing endorses the FAA rules related to Limit of Validity (LOV) and recommends immediate and permanent removal from service of any airplanes upon reaching the LOV, whether or not it is operated under FAA jurisdiction. As such, Boeing no longer provides maintenance instructions for airplanes that have accumulated flight cycles beyond the LOV. Airplanes in Group 1 (line numbers 1-291) have accumulated flight cycles beyond the LOV of the maintenance program. 14 CFR 121.1115 and 129.115 prohibit operation of an airplane beyond its LOV. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 16 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 17 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Refer to the listed procedures in SB 737- 57A1353 Original Is- sue or later approved revisions as an ac- cepted procedure Method of ComplianceActionCondition PART 1: GET ACCESS FOR OPTION 1 OPEN HOLE HFEC INSPEC- TION. -OPTION 1: Do an open hole High Frequency Eddy Current (HFEC) inspection of the wing rear spar lower chord at the Main Landing Gear (MLG) aft fitting at Wing Buttock Line (WBL)157 for any crack. All Airplanes. PART 5: FASTENER REMOVAL FOR OP- TION 1 OPEN HOLE HFEC INSPECTION. - -LEFT SIDE: FIGURE 3 RIGHT SIDE: FIGURE 4 PART 2: GET ACCESS FOR OPTION 2 SUR- FACE HFEC AND UT INSPECTION. -OPTION 2: Do a surface HFEC inspection and ultrasonic (UT) inspection of the wing rear spar lower chord at the MLG aft fit- ting at WBL 157 for any crack. -LEFT SIDE: FIGURE 13 RIGHT SIDE: FIGURE 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 17 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 18 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Refer to the listed procedures in SB 737- 57A1353 Original Is- sue or later approved revisions as an ac- cepted procedure Method of ComplianceActionCondition --CONDITION 1 (ACTION 1): Contact The Boeing Company for repair instructions and do the repair. CONDITION 1: ANY CRACK FOUND DURING OPTION 1 OPEN HOLE HFEC INSPECTION. PART 3: CLOSE AC- CESS FOR OPTION 1 OPEN HOLE HFEC IN- SPECTION. Group 2, Configuration 1: LEFT SIDE: FIGURE 5 RIGHT SIDE: FIGURE 6 Group 2, Configuration 2: CONDITION 1 (ACTION 2): In- stall fasteners. LEFT SIDE: FIGURE 7 RIGHT SIDE: FIGURE 8 Group 3, Configuration 1: LEFT SIDE: FIGURE 9 RIGHT SIDE: FIGURE 10 Group 3, Configuration 2: LEFT SIDE: FIGURE 11 RIGHT SIDE: FIGURE 12 PART 1: GET ACCESS FOR OPTION 1 OPEN HOLE HFEC INSPEC- TION. -CONDITION 1 (ACTION 3) (OPTION 1): Repeat open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) PART 5: FASTENERREMOVAL FOR OP- TION 1 OPEN HOLE HFEC INSPECTION. - -LEFT SIDE: FIGURE 3 RIGHT SIDE: FIGURE 4 PART 2: GET ACCESS FOR OPTION 2 SUR- FACE HFEC AND UT INSPECTIONS. -CONDITION 1 (ACTION 3) (OPTION 2): Do a surface HFEC inspection and UT inspec- tion of the wing rear spar lower chord at the MLG aft fitting and below the aft fitting at WBL 157 for any crack. (a)(b) -LEFT SIDE: FIGURE 13 RIGHT SIDE: FIGURE 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 18 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 19 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Refer to the listed procedures in SB 737- 57A1353 Original Is- sue or later approved revisions as an ac- cepted procedure Method of ComplianceActionCondition PART 3: CLOSE AC- CESS FOR OPTION 1 OPEN HOLE HFEC IN- SPECTION. Group 2, Configuration 1: LEFT SIDE: FIGURE 5 RIGHT SIDE: FIGURE 6 Group 2, Configuration 2: CONDITION 2 (ACTION 1): In- stall Fasteners. CONDITION 2: NO CRACK FOUND DURING OPTION 1 OPEN HOLE HFEC INSPECTION. LEFT SIDE: FIGURE 7 RIGHT SIDE: FIGURE 8 Group 3, Configuration 1: LEFT SIDE: FIGURE 9 RIGHT SIDE: FIGURE 10 Group 3, Configuration 2: LEFT SIDE: FIGURE 11 RIGHT SIDE: FIGURE 12 PART 1: GET ACCESS FOR OPTION 1 OPEN HOLE HFEC INSPEC- TION. -CONDITION 2 (ACTION 2) (OPTION 1): Repeat open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) PART 5: FASTENERREMOVAL FOR OP- TION 1 OPEN HOLE HFEC INSPECTION. - -LEFT SIDE: FIGURE 3 RIGHT SIDE: FIGURE 4 PART 2: GET ACCESS FOR OPTION 2 SUR- FACE HFEC AND IN- SPECTIONS. -CONDITION 2 (ACTION 2) (OPTION 2): Do a surface HFEC inspection and UT inspec- tion of the wing rear spar lower chord at the MLG aft fitting and below the aft fitting at WBL 157 for any crack. (a)(b) -LEFT SIDE: FIGURE 13 RIGHT SIDE: FIGURE 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 19 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 20 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Refer to the listed procedures in SB 737- 57A1353 Original Is- sue or later approved revisions as an ac- cepted procedure Method of ComplianceActionCondition --CONDITION 3 (ACTION 1): Contact The Boeing Company for repair instructions and do the repair. CONDITION 3: ANY CRACK FOUND DURING OPTION 2 SURFACE HFEC AND UT INSPEC- TIONS. PART 4: CLOSE AC- CESS FOR OPTION 2 SURFACE HFEC AND UT INSPECTIONS. - PART 1: GET ACCESS FOR OPTION 1 OPEN HOLE HFEC INSPEC- TION. -CONDITION 3 (ACTION 2) (OPTION 1): Do an open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) PART 5: FASTENERREMOVAL FOR OP- TION 1 OPEN HOLE HFEC INSPECTION. - -LEFT SIDE: FIGURE 3 RIGHT SIDE: FIGURE 4 Do PART 2: GET AC- CESS FOR OPTION 2 SURFACE HFEC AND UT INSPECTIONS. -CONDITION 3 (ACTION 2) (OPTION 2): Repeat surface HFEC inspection and UT inspec- tion of the wing rear spar lower chord at the MLG aft fitting and below the aft fitting at WBL 157 for any crack. (a)(b) -LEFT SIDE: FIGURE 13 RIGHT SIDE: FIGURE 14 Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 20 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 21 Group 2-3: Table 1: Open Hole High Frequency Eddy Current (HFEC) Inspection or Surface HFEC and Ultrasonic (UT) Inspection of the Wing Rear Spar Lower Chord at the Main Landing Gear (MLG) Aft Fitting at Wing Buttock Line (WBL) 157 Left and Right Side Refer to the listed procedures in SB 737- 57A1353 Original Is- sue or later approved revisions as an ac- cepted procedure Method of ComplianceActionCondition PART 4: CLOSE AC- CESS FOR OPTION 2 SURFACE HFEC AND UT INSPECTIONS. -CONDITION 4 (OPTION 1): Do an open hole HFEC inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) CONDITION 4: NO CRACK FOUND DURING OPTION 2 SURFACE HFEC AND UT INSPEC- TIONS. PART 1: GET ACCESSFOR OPTION 1 OPEN HOLE HFEC INSPEC- TION. - PART 5: FASTENER REMOVAL FOR OP- TION 1 OPEN HOLE HFEC INSPECTION. - -LEFT SIDE: FIGURE 3 RIGHT SIDE: FIGURE 4 PART 2: GET ACCESS FOR OPTION 2 SUR- FACE HFEC AND UT INSPECTIONS. -CONDITION 4 (OPTION 2): Repeat surface HFEC inspec- tion and UT inspection of the wing rear spar lower chord at the MLG aft fitting at WBL 157 for any crack. (a)(b) -LEFT SIDE: FIGURE 13RIGHT SIDE: FIGURE 14 (a) After the accomplishment of this OPTION, it is acceptable to change the repeat action from this OPTION to any other OPTION under this CONDITION. (b) It is not required to do the inspection in areas where a repair covers the affected inspection area if the repairs meets the conditions that follow: 1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737- 57A1353 RB and installed after the original issue date of Requirements Bulletin 737-57A1353 RB. 2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA) via a FAA Form 8100-9. Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 21 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 22 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2-3. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). FWD TYPICAL MLG AND MLG SUPPORT BEAM WING REAR WING UPPER WBL SHOWN FOR REFERENCE ONLY SPAR UPPER SKIN 157 STIFFENER CHORD STIFFENER WING REAR SPAR WEB WING REAR SPAR LOWER CHORD WING LOWER FITTING MLG AFT TYPICAL CRACK FITTING MLG FORWARD INBD SKIN VIEW LOOKING FORWARD _ AT WING REAR SPAR A-A 2981902 - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 3: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION (SHEET 1 OF 2) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 22 of 57 ### Page 23 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)4-OPEN HOLEInspect1 (a) Do an open hole HFEC inspection of the fastener holes for any crack in accordance with 737 NDT Man- ual Part 6, 51-00-00, Procedure 1, 11 or 16. NOTE: Use the steps in 737 NDT Manual Part 6, 51-00-00, Procedure 16 Paragraph 7 to confirm crack indication(s). Discrepancies in shims can cause false positive crack indications. If an indication can be confirmed to be at the same depth and radial position as the discrepancy location, the fastener hole can be accepted. A discrepancy is defined as a cut or rip in the shim, a shim that has migrated past the edge of the hole, or a gap caused by shim migration outward. FIGURE 3: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION (SHEET 2 OF 2) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 23 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 24 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2-3. MAIN LANDING GEAR (MLG) WBL SUPPORT BEAM 157 FWD _ TYPICAL MLG AND MLG SUPPORT BEAM SHOWN FOR REFERENCE ONLY WBL 157 WING UPPER SKIN WING REAR SPAR UPPER STIFFENER CHORD STIFFENER WING REAR SPAR WEB MLG FORWARD TYPICAL MLG AFT WING REAR NBD FITTING CRACK FITTING WING SPAR LOWER LOWER CHORD A-A SKIN VIEW LOOKING FORWARD AT WING REAR SPAR - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 4: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION (SHEET 1 OF 2) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 24 of 57 ### Page 25 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)4-OPEN HOLEInspect1 (a) Do an open hole HFEC inspection of the fastener holes for any crack in accordance with 737 NDT Man- ual Part 6, 51-00-00, Procedure 1, 11 or 16. NOTE: Use the steps in 737 NDT Manual Part 6, 51-00-00, Procedure 16 Paragraph 7 to confirm crack indication(s). Discrepancies in shims can cause false positive crack indications. If an indication can be confirmed to be at the same depth and radial position as the discrepancy location, the fastener hole can be accepted. A discrepancy is defined as a cut or rip in the shim, a shim that has migrated past the edge of the hole, or a gap caused by shim migration outward. FIGURE 4: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION (SHEET 2 OF 2) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 25 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 26 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2, Configuration 1. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). TYPICAL MLG AND MLG SUPPORT BEAM WING REAR SPAR UPPER WING UPPER WBL SHOWN FOR REFERENCE ONLY STIFFENER CHORD SKIN 157 STIFFENER WING REAR SPAR WEB A 10F 120 1 OF A 10F 120, 20 WING REAR CHORD SPAR LOWER MLG AFI FITTING VIEW LOOKING FORWARD AT WING REAR SPAR SKING LOWER A-A4 LOCATIONS SKIN FITTING MLG FORWARD INBD 2981904 REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 5: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 4) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 26 of 57 ### Page 27 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the transition fit hole size (Ref 0.309-0.313 inch diameter transition fit hole size for airplanes as delivered condition). For 0.309-0.313 inch diameter initial hole location or up to 0.3261 inch diameter clean-up reamed hole location, ream final hole size to 0.3241-0.3261 inch diameter (1st oversize 0.0005/0.0035 interference fit) and install specified 1st oversize bolt and its mating collar. For up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch di- ameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 5: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 27 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 28 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(f)0.309-0.3134BACB30NX10K()BOLT (NOMINAL)A -4BACC30BH10COLLAR (b)(d)(e)(f)0.3241-0.3261-BACB30NX10K()XBOLT (1ST OVER- SIZE) --BACC30BH10COLLAR (d)(e)(f)03241-0.3261-BACB30MC10A()BOLT (1ST OVER- SIZE) --BACC30BH10COLLAR (d)(e)(f)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (c)(d)(e)(f)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.309-0.313 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate first oversize fastener. (c) Alternate second oversize fastener. (d) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. FIGURE 5: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 28 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 29 More DataHole DiaQtyIdentificationNameCode (e) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in either 0.3241-0.3261 or 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Those four fastener locations can be installed with mix of first oversize and second oversize fasteners in 0.0005/0.0035 interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 inter- ference fit holes at those four depicted fastener locations. (f) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 5: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 4 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 29 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 30 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2, Configuration 1. MAIN LANDING GEAR (MLG) WBL 157 SUPPORT BEAM TYPICAL SHOWN FOR REFERENCE ONLY MLG AND MLG SUPPORT BEAM WBL WING UPPER SPAR UPPER WING REAR STIFFENER 157 SKIN CHORD STIFFENER WING REAR SPAR WEB A 10F Izo A 10F 120 NBD MLG FORWARD FITTING 4 LOCATIONS A-A SKIN WING LOWER MLG AFT FITTING WING REAR CHORD SPAR LOWER VIEW LOOKING FORWARD AT WING REAR SPAR • REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 6: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 4) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 30 of 57 ### Page 31 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the transition fit hole size (Ref 0.309-0.313 inch diameter transition fit hole size for airplanes as delivered condition). For 0.309-0.313 inch diameter initial hole location or up to 0.3261 inch diameter clean-up reamed hole location, ream final hole size to 0.3241-0.3261 inch diameter (1st oversize 0.0005/0.0035 interference fit) and install specified 1st oversize bolt and its mating collar. For up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch di- ameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 6: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 31 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 32 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(f)0.309-0.3134BACB30NX10K()BOLT (NOMINAL)A -4BACC30BH10COLLAR (b)(d)(e)(f)0.3241-0.3261-BACB30NX10K()XBOLT (1ST OVER- SIZE) --BACC30BH10COLLAR (d)(e)(f)03241-0.3261-BACB30MC10A()BOLT (1ST OVER- SIZE) --BACC30BH10COLLAR (d)(e)(f)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (c)(d)(e)(f)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.309-0.313 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate first oversize fastener. (c) Alternate second oversize fastener. (d) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. FIGURE 6: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 32 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 33 More DataHole DiaQtyIdentificationNameCode (e) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in either 0.3241-0.3261 or 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Those four fastener locations can be installed with mix of first oversize and second oversize fasteners in 0.0005/0.0035 interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 inter- ference fit holes at those four depicted fastener locations. (f) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 6: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 4 OF 4) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 33 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 34 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2, Configuration 2. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). FWD TYPICAL MLG AND MLG SUPPORT BEAM WING REAR WING UPPER WBL SHOWN FOR REFERENCE ONLY SPAR UPPER SKIN 157 STIFFENER CHORD STIFFENER WING REAR SPAR WEB B |10F 121 B 10F B 10 WING REAR SPAR LOWER CHORD MLG AFT FITTING WING LOWER SKIN 4 LOCATIONS FITTING MLG FORWARD INBD VIEW LOOKING FORWARD AT WING REAR SPAR A-A 2987673 • REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 7: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 34 of 57 ### 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the 1st oversize transition fit hole size (Ref 0.325-0.328 inch diameter transition fit hole size for airplanes with service bulletin 737-57-1216 modification). For 0.325-0.328 inch diameter initial hole location or up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch diameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 7: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 35 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 36 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(e)0.325-0.3284BACB30NX10K()XBOLT (1ST OVER- SIZE) B -4BACC30BH10COLLAR (c)(d)(e)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (b)(c)(d)(e)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.325-0.328 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate second oversize fastener. (c) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 interference fit holes at those four depicted fastener locations. (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 7: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 36 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 37 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2, Configuration 2. MAIN LANDING GEAR (MLG) WBL SUPPORT BEAM 157 FWD MLG AND MLG SUPPORT BEAM TYPICAL SHOWN FOR REFERENCE ONLY WBL 157 WING UPPER SKIN WING REAR SPAR UPPER STIFFENER STIFFENER CHORD WING REAR SPAR WEB B 10I B |10F 121 B 10 B 10F 214- MLG FORWARD 12) MLG AFT WING REAR NBD FITTING WING LOWER FITTING SPAR LOWER 4 LOCATIONS SKIN CHORD A-A VIEW LOOKING FORWARD AT WING REAR SPAR • - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 8: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 37 of 57 ### Page 38 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the 1st oversize transition fit hole size (Ref 0.325-0.328 inch diameter transition fit hole size for airplanes with service bulletin 737-57-1216 modification). For 0.325-0.328 inch diameter initial hole location or up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch diameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 8: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 38 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 39 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(e)0.325-0.3284BACB30NX10K()XBOLT (1ST OVER- SIZE) B -4BACC30BH10COLLAR (c)(d)(e)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (b)(c)(d)(e)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.325-0.328 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate second oversize fastener. (c) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 interference fit holes at those four depicted fastener locations. (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 8: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 39 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 40 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 3, Configuration 1. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). TYPICAL MLG AND MLG SUPPORT BEAM WING REAR SPAR UPPER WING UPPER WBL SHOWN FOR REFERENCE ONLY STIFFENER CHORD SKIN 157 STIFFENER WING REAR SPAR WEB C 10F 122 C†1 10I C 10F 122, 22 WING REAR SPAR LOWER MLG AF MLG FORWARD INBD CHORD FITTING WING LOWER A-A+ LOCATIONS FITTING VIEW LOOKING FORWARD AT WING REAR SPAR SKIN 2987674 REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 9: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 40 of 57 ### Page 41 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the transition fit hole size (Ref 0.309-0.313 inch diameter transition fit hole size for airplanes as delivered condition). For 0.309-0.313 inch diameter initial hole location or up to 0.3261 inch diameter clean-up reamed hole location, ream final hole size to 0.3241-0.3261 inch diameter (1st oversize 0.0005/0.0035 interference fit) and install specified 1st oversize bolt and its mating collar. For up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch di- ameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 9: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 41 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 42 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(c)(e)0.309-0.3134HLT422AP10-( )BOLT (NOMINAL)C -4HL73BP10COLLAR (a)(b)(c)(e)0.309-0.313-BACB30YK10K()BOLT (NOMINAL) --BACC30CP10CCOLLAR (d)(e)0.3241-0.3261-BACB30YK10K()XBOLT (1ST OVER- SIZE) --BACC30CP10CCOLLAR (d)(e)0.3397-0.3417-BACB30YK10K()YBOLT (2ND OVER- SIZE) --BACC30CP10CYCOLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.309-0.313 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate nominal fastener. (c) HLT422AP10-( ) bolt is equivalent to BACB30YK10K( ) bolt. HL73BP10 collar is equivalent to BACC30CP10C collar. Acceptable to mix HLT422AP10-( ) bolt with BACB30YK10K( ) bolt and HL73BP10 collar with BACC30CP10C collar at all four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in either 0.3241-0.3261 or 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Those four fastener locations can be installed with mix of first oversize and second oversize fasteners in 0.0005/0.0035 interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 inter- ference fit holes at those four depicted fastener locations. (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 9: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 42 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 43 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 3, Configuration 1. WBL MAIN LANDING GEAR (MLG) 157 SUPPORT BEAM TYPICAL MLG AND MLG SUPPORT BEAM SHOWN FOR REFERENCE ONLY WBL WING UPPER WING REAR SPAR UPPER STIFFENER 15- SKIN CHORD STIFFENER WING REAR SPAR WEB C 10F 122 C 10F 122. WING REAR INBD MLG FORWARD FITTING 4 LOCATIONS A-A SKIN WING LOWER MLG AFT FITTING SPAR LOWER CHORD VIEW LOOKING FORWARD AT WING REAR SPAR • - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 10: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 43 of 57 ### Page 44 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the transition fit hole size (Ref 0.309-0.313 inch diameter transition fit hole size for airplanes as delivered condition). For 0.309-0.313 inch diameter initial hole location or up to 0.3261 inch diameter clean-up reamed hole location, ream final hole size to 0.3241-0.3261 inch diameter (1st oversize 0.0005/0.0035 interference fit) and install specified 1st oversize bolt and its mating collar. For up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch di- ameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 10: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 44 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 45 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(c)(e)0.309-0.3134HLT422AP10-( )BOLT (NOMINAL)C -4HL73BP10COLLAR (a)(b)(c)(e)0.309-0.313-BACB30YK10K()BOLT (NOMINAL) --BACC30CP10CCOLLAR (d)(e)0.3241-0.3261-BACB30YK10K()XBOLT (1ST OVER- SIZE) --BACC30CP10CCOLLAR (d)(e)0.3397-0.3417-BACB30YK10K()YBOLT (2ND OVER- SIZE) --BACC30CP10CYCOLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.309-0.313 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate nominal fastener. (c) HLT422AP10-( ) bolt is equivalent to BACB30YK10K( ) bolt. HL73BP10 collar is equivalent to BACC30CP10C collar. Acceptable to mix HLT422AP10-( ) bolt with BACB30YK10K( ) bolt and HL73BP10 collar with BACC30CP10C collar at all four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in either 0.3241-0.3261 or 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Those four fastener locations can be installed with mix of first oversize and second oversize fasteners in 0.0005/0.0035 interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 inter- ference fit holes at those four depicted fastener locations. (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 10: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 45 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 46 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 3, Configuration 2. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). FWD TYPICAL MLG AND MLG SUPPORT BEAM WING REAR WING UPPER WBL SHOWN FOR REFERENCE ONLY SPAR UPPER SKIN 157 STIFFENER CHORD STIFFENER WING REAR SPAR WEB D 10F 122 D 10F D 10F WING REAR SPAR LOWER CHORD FITTING MLG AFT WING LOWER SKIN 4 LOCATIONS MLG FORWARD FITTING INBD VIEW LOOKING FORWARD AT WING REAR SPAR A-A 2987675 REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 11: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 46 of 57 ### Page 47 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the 1st oversize transition fit hole size (Ref 0.325-0.328 inch diameter transition fit hole size for airplanes with service bulletin 737-57-1216 modification). For 0.325-0.328 inch diameter initial hole location or up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch diameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 11: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 47 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 48 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(e)0.325-0.3284BACB30NX10K()XBOLT (1ST OVER- SIZE) D -4BACC30BH10COLLAR (c)(d)(e)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (b)(c)(d)(e)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.325-0.328 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate second oversize fastener. (c) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 interference fit holes at those four depicted fastener locations (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 11: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 48 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 49 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 3, Configuration 2. MAIN LANDING GEAR (MLG) WBL SUPPORT BEAM 157 FWD MLG AND MLG SUPPORT BEAM TYPICAL SHOWN FOR REFERENCE ONLY WBL 157 WING UPPER SKIN WING REAR SPAR UPPER STIFFENER STIFFENER CHORD WING REAR SPAR WEB D 10F 122 D 10F D 10F 224J MLG FORWARD 12) MLG AFT WING REAR NBD FITTING WING LOWER FITTING SPAR LOWER 4 LOCATIONS SKIN CHORD A-A VIEW LOOKING FORWARD AT WING REAR SPAR • - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 12: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 49 of 57 ### Page 50 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)(b)--FASTENER HOLE(S)Ream1 (a)(b)(c)(d)(e)4-FASTENERInstall (New)2 (a)(b)(c)(e)4-COLLARInstall (New) (f)-BMS 5-45SEALANTApply3 (a) The four depicted fastener hole locations must meet one of the fastener installation requirements that follow: 1. If all four holes are not enlarged for clean-up ream during the fastener removal step, install the same hexdrive bolt and collar type as recorded in fastener removal step. No hole reaming is required. 2. If clean-up ream is done on any one or more of the four holes, all remaining hole(s) that are not clean- up reamed must not remain in the 1st oversize transition fit hole size (Ref 0.325-0.328 inch diameter transition fit hole size for airplanes with service bulletin 737-57-1216 modification). For 0.325-0.328 inch diameter initial hole location or up to 0.3417 inch diameter clean-up reamed hole location, ream final hole size to 0.3397-0.3417 inch diameter (2nd oversize 0.0005/0.0035 interference fit) and install specified 2nd oversize bolt and its mating collar. (b) Install new fasteners. Refer to 737-100/200 SRM 51-30-02, 737-300 SRM 51-40-02, 737-400 SRM 51- 40-02, or 737-500 SRM 51-40-02 as an accepted procedure. Install approved substitute fasteners in ac- cordance with 737-100/200 SRM 51-30-03, 737-300 SRM 51-40-03, 737-400 SRM 51-40-03 or 737-500 SRM 51-40-03. (c) Refer to the fastener code table. (d) Install fasteners wet with BMS 5-45 sealant. Refer to SOPM 20-50-19, Method 2 as an accepted procedure. (e) Collar must be installed on the outside of the fuel tank. (f) Completely encapsulate end of fastener that is inside the fuel tank using BMS 5-45 sealant in accordance with 737-100/200 SRM 51-10-12, 737-300 SRM 51-80-01, 737-400 SRM 51-80-01 or 737-500 SRM 51- 80-01. Completely encapsulate end of fastener that is outside the fuel tank for corrosion protection sealing requirements. Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 12: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 2 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 50 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 51 The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure. 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)(e)0.325-0.3284BACB30NX10K()XBOLT (1ST OVER- SIZE) D -4BACC30BH10COLLAR (c)(d)(e)0.3397-0.3417-BACB30NX10K()YBOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (b)(c)(d)(e)0.3397-0.3417-BACB30MD10A()BOLT (2ND OVER- SIZE) --BACC30AC10COLLAR (a) Install fastener at all four depicted fastener holes if all four hole diameters are within 0.325-0.328 without clean-up ream done during the fastener removal step and without crack indication found during the open hole HFEC inspection step. (b) Alternate second oversize fastener. (c) Whether using primary or alternate bolts, all four depicted fastener locations must use bolts made from the same material alloy and with the same type specification. Do not mix bolts made from different mate- rial alloy or with different type specification at those four depicted fastener locations. (d) Once clean-up ream was done on any one or more fastener location(s) during the fastener removal step, all four fasteners must be installed in 0.3397-0.3417 (0.0005/0.0035) interference fit holes. Do not mix transition fit holes with 0.0005/0.0035 interference fit holes at those four depicted fastener locations (e) Check fastener grip length prior to fastener installation. Adjust grip length as required. FIGURE 12: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - FASTENER INSTALLATION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 51 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 52 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2-3. WBL 157 SUPPORT BEAM MAIN LANDING GEAR (MLG). FWD TYPICAL MLG AND MLG SUPPORT BEAM WING REAR WING UPPER WBL SHOWN FOR REFERENCE ONLY SPAR UPPER SKIN 157 STIFFENER CHORD STIFFENER WING REAR SPAR WEB WING REAR SPAR LOWER CHORD MLG AFT FITTING WING LOWER MLG FORWARD FITTING INBD SKIN A-A VIEW LOOKING FORWARD AT WING REAR SPAR • REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 13: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 52 of 57 ### Page 53 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT WBL TYPICAL 157 CRACK MLG AFT FITTING MLG AFT FITTING WING REAR SPAR WEB WING WING REAR LOWER SPAR LOWER SKIN CHORD 0.75 INCH 0.75 INCH MINIMUM MINIMUM INBD WING LOWER SKIN FWD WING REAR SPAR LOWER CHORD SURFACE HFEC INSPECTION B-B ULTRASONIC INSPECTION FIGURE 13: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 2 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 53 of 57 ### 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)-65-45325-()REAR SPAR LOWER CHORD Inspect1 (b)-65-45325-()REAR SPAR LOWER CHORD Inspect2 (a) Do a surface HFEC inspection of the wing rear spar lower chord below the MLG aft fitting at WBL 157 for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 4 or Procedure 23. (b) Do an ultrasonic inspection of the wing rear spar lower chord for any crack around the four depicted fas- teners in accordance with 737 NDT Manual Part 4, 57-50-07. FIGURE 13: LEFT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 54 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT ### Page 55 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT This Figure applies only to: Group 2-3. MAIN LANDING GEAR (MLG) WBL SUPPORT BEAM 157 FWD MLG AND MLG SUPPORT BEAM TYPICAL SHOWN FOR REFERENCE ONLY WBL 157 • WING UPPER SKIN WING REAR SPAR UPPER STIFFENER STIFFENER CHORD WING REAR SPAR WEB FORWARD MLG AFT WING REAR NBD FITTING WING LOWER FITTING SPAR LOWER SKIN A-A CHORD VIEW LOOKING FORWARD AT WING REAR SPAR - REFERENCE FASTENER (STRUCTURE MAY NOT BE EXACTLY AS SHOWN) FIGURE 14: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 1 OF 3) Original Issue: February 10, 2022 737-57A1353 RB Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. 55 of 57 ### Page 56 (OCR) REQUIREMENTS BULLETIN 737-57A1353 ALERT ALERT WBL 157 TYPICAL CRACK MLG AFT FITTING MLG AFT FITTING WING REAR WING REAR WING SPAR WEB SPAR LOWER LOWER CHORD SKIN 0.75 INCH 0.75 INCH MINIMUM MINIMUM INBD WING REAR SPAR LOWER CHORD SKIN WING LOWER FWD SURFACE HFEC INSPECTION B-B ULTRASONIC INSPECTION 2982093 FIGURE 14: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 2 OF 3) Original Issue: February 10, 2022 Export Controlled ECCN: 9E991 737-57A1353 RB Copyright © Unpublished Work - See page 1 for details. 56 of 57 ### 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)-65-45325-()REAR SPAR LOWER CHORD Inspect1 (b)-65-45325-()REAR SPAR LOWER CHORD Inspect2 (a) Do a surface HFEC inspection of the wing rear spar lower chord below the MLG aft fitting at WBL 157 for any crack in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 4 or Procedure 23. (b) Do an ultrasonic inspection of the wing rear spar lower chord for any crack around the four depicted fas- teners in accordance with 737 NDT Manual Part 4, 57-50-07. FIGURE 14: RIGHT SIDE - WING REAR SPAR LOWER CHORD AT THE MLG AFT FITTING - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION AND ULTRASONIC (UT) INSPECTION (SHEET 3 OF 3) Export Controlled ECCN: 9E991 Copyright © Unpublished Work - See page 1 for details. Original Issue: February 10, 2022 737-57A1353 RB 57 of 57 REQUIREMENTS BULLETIN 737-57A1353 ALERTALERT --- 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.