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Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1325 Original Issue: December 03, 2013 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Body Station (STA) 727 Bulkhead Lower Frame Web and Inner Chord - Inspection, Preventive Modification and Repair 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: BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2013 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 Unpublished Work.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: December 03, 2013 737-53A1325 1 of 138 6.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 2 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Summary ...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity ................................................ 9 1. Airplanes ............................................. 9 2. Spares Affected ........................................ 1 2 B. Concurrent Requirements ...................................... 1 2 C. Reason ................................................ 1 2 D. Description .............................................. 1 3 E. Compliance .............................................. 1 4 F. Approval ............................................... 2 3 G. Manpower .............................................. 2 3 H. Weight and Balance Changes .................................... 2 6 I. Electrical Load Data ......................................... 2 6 J. References .............................................. 2 6 1. Existing Data: ......................................... 2 6 2. Data Supplied with this Service Bulletin: ........................... 2 7 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 2 7 K. Publications Affected ........................................ 2 7 L. Interchangeability and Intermixability of Parts ........................... 2 7 M. Software Accomplishment Summary ................................ 2 7 2. MATERIAL INFORMATION ........................................ 2 9 A. Material - Price and Availability ................................... 2 9 B. Industry Support Information .................................... 2 9 C. Parts Necessary for Each Airplane ................................. 3 0 1. Kits/Parts: ........................................... 3 0 2. Parts and Materials Supplied by the Operator: ........................ 3 4 3. Parts Modified and Reidentified: ............................... 3 4 4. Parts Removed and Not Replaced: .............................. 3 4 D. Parts Necessary to Change Spares ................................. 3 4 E. Special Tooling - Price and Availability ............................... 3 4 F. Special Tooling Necessary to do this Service Bulletin ....................... 3 5 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 7 A. GENERAL INFORMATION ..................................... 3 7 B. WORK INSTRUCTIONS ....................................... 3 8 FIGURE 1: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - LEFT AND RIGHT SIDE [Group 1] .................................. 4 5 FIGURE 2: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - RIGHT SIDE [Group 2-3] .................................... 4 9 FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE [Group 1] ............................................ 5 2 FIGURE 4: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - RIGHT SIDE .................................................. 5 7 FIGURE 5: BODY STATION (STA) 727 LOWER FRAME REPAIR 1 - LEFT SIDE [Group 1] ..... 6 2 FIGURE 6: BODY STATION (STA) 727 LOWER FRAME REPAIR 1 - RIGHT SIDE .......... 6 9 FIGURE 7: BODY STATION (STA) 727 LOWER FRAME REPAIR 2 - LEFT SIDE [Group 1] ..... 7 6 FIGURE 8: BODY STATION (STA) 727 LOWER FRAME REPAIR 2 - RIGHT SIDE .......... 8 5 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 3 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 4 FIGURE 9: BODY STATION (STA) 727 LOWER FRAME REPAIR 3 - LEFT SIDE [Group 1] ..... 9 4 FIGURE 10: BODY STATION (STA) 727 LOWER FRAME REPAIR 3 - RIGHT SIDE ......... 1 0 3 FIGURE 11: LEFT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 1 INSPECTIONS [Group 1, 3] .......................................... 1 1 2 FIGURE 12: RIGHT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 1 INSPECTIONS ................................................. 1 1 5 FIGURE 13: LEFT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 2 INSPECTIONS [Group 1] ............................................ 1 1 8 FIGURE 14: RIGHT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 2 INSPECTIONS ................................................. 1 2 1 FIGURE 15: LEFT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 3 INSPECTIONS [Group 1] ............................................ 1 2 4 FIGURE 16: RIGHT SIDE - LOWER FRAME WEB AND INNER CHORD - POST REPAIR 3 INSPECTIONS ................................................. 1 2 7 FIGURE 17: LEFT SIDE - LOWER FRAME WEB AND INNER CHORD - POST PREVENTIVE MODIFICATION INSPECTIONS [Group 1] ................................... 1 3 0 FIGURE 18: RIGHT SIDE - LOWER FRAME WEB AND INNER CHORD - POST PREVENTIVE MODIFICATION INSPECTIONS ............................... 1 3 3 APPENDIX A: COMPLIANCE FLOW DIAGRAM FOR STA 727 FRAME INSPECTION, REPAIR AND MODIFICATION [Group 1] .................................. 1 3 6 APPENDIX B: COMPLIANCE FLOW DIAGRAM FOR RIGHT SIDE STA 727 FRAME INSPECTION, REPAIR AND MODIFICATION [Group 2] ............................... 1 3 7 APPENDIX C: COMPLIANCE FLOW DIAGRAM FOR STA 727 FRAME INSPECTION, REPAIR AND MODIFICATION [Group 3] .................................. 1 3 8 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 4 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-53A1325Original Issue: December 03, 2013 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Body Station (STA) 727 Bulkhead Lower Frame Web and Inner Chord - Inspection, Preventive Modification and Repair THIS BULLETIN 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 SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. CONCURRENT REQUIREMENTS None. BACKGROUND The inspections given in this service bulletin will detect cracks in the Body Station (STA) 727 bulkhead lower frame web and inner chord before they reach a critical length. The changes given in this service bulletin will decrease the occurrence of cracks at the STA 727 bulkhead lower frame web and inner chord. This area is a primary structural element (PSE). If the inspections given in this service bulletin are not accomplished undetected cracks could result in severed frames and induced skin cracks at these locations. This could lead to rapid decompression of the fuselage. The STA 727 bulkhead lower frames have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). Boeing has received reports of cracking on four airplanes in the lower bulkhead frame as shown in the service history table below. Service History - Model 737-600/-700 ReportFlight Cycles/Flight- hours One crack extending 0.25 inches outboard from the fastener hole. (a)25,544/ 44,100 One crack extending 0.50 inches outboard from the fastener hole. (a)23,682/ 40,381 One crack extending 0.50 inch outboard from the fastener hole, and one crack extending inboard through the frame radius into the inner chord flange. (a) 25,616/ 44,061 One crack was found at a fastener in the STA 727 frame web at Left Buttock Line (LBL) 60. The crack measures 0.50 inch, extending inboard. (a) 25,435/43,543 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 5 of 138 ### Page 6 Service History - Model 737-600/-700 ReportFlight Cycles/Flight- hours (a) All cracks reported occur in the lower frame web and originates at the 5/16 Inch diameter fastener location adjacent to the inboard chord and common to the STA 727 bulkhead compression chord. 737-600/700 airplanes after line number 1179 have a different frame assembly installed in production that has a thicker web and chord in the areas prone to cracking. Airplanes variable number YA026, YA035, and YA036 had a repair installed in the left side STA 727 Bulkhead lower frame web before the original issue of this service bulletin. Airplane variable number YA075 had a repair, which is equivalent to Repair 1 in this service bulletin, installed in the left side STA 727 Bulkhead lower frame web before the original issue of this service bulletin. Boeing Service Related Problem (SRP) 737NG-53-0384 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information. ReferenceAffectedPlanning Data Paragraph 1.A.2., Spares AffectedNoSpares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval YesAD Related Paragraph 1.H., Weight and Balance ChangesYesWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedNoPublications Affected Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew Operations Manual and/or FAA Approved Air- plane Flight Manual) Paragraph 2.C.1., Kits/PartsYesKits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator YesOperator Supplied Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin NoSpecial Tooling Required ACTION (PRR 38275-185RS) Group 1: Do detailed inspections on the left and right side, for cracking in the lower frame web and inner chord at STA 727, and an open hole high frequency eddy current (HFEC) inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable left or right side repair in accordance with this service bulletin. If a repair or modification is not installed, repeat the inspection. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 6 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 7 Group 2: Do detailed inspections on the right side only, for cracking in the lower frame web and inner chord at STA 727, and an open hole HFEC inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable right side repair in accordance with this service bulletin. If a repair or modification is not installed, repeat the inspection. Contact Boeing for left side inspection and modification instructions, and do the work instructed by Boeing. Group 3: Do detailed inspections on the right side, for cracking in the lower frame web and inner chord at STA 727, and an open hole HFEC inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the right lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the right lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable right side repair in accordance with this service bulletin. If a repair or modification is not installed on the right side, repeat the inspection. Do a HFEC inspection for any cracking in the modified left lower frame web and inner chord at STA 727. If any crack is found on the lower frame web, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found on the left side, repeat the inspection. Group 1: Do post repair/post modification inspections on the left and right side, for cracks in the lower frame web and inner chord. If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. Group 2-3: Do post repair/post modification inspections on the right side only, for cracks in the lower frame web and inner chord. If any crack is found contact Boeing for the repair instructions and do the work instructed by Boeing. EFFECTIVITY 737-600/700 passenger airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. COMPLIANCE The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are available for airplanes in warranty as of June 2, 2011. Please refer to Paragraph 2.B., Industry Support Information. MANPOWER Refer to Paragraph 1.G., Manpower. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 7 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 8 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT MATERIAL INFORMATION Boeing Supplied Kits Refer to Paragraph 2.A., Material - Price and Availability. STA 727 STA 727 INSPECT FOR CRACKS IN THE LOWER FRAME WEB AND INNER CHORD. IF ANY CRACK IS FOUND, INSTALL A REPAIR. IF NO CRACKING IS FOUND, INSTALL A MODIFICATION OR CONTINUE REPEAT INSPECTIONS DO POST MODIFICATION /REPAIR INSPECTION OF THE LOWER FRAME AT GIVEN INTERVALS. 2178688 Original Issue: December 03, 2013 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1325 Work - See page 1 for details. 8 of 138 ### Page 9 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-53A1325 Original Issue: December 03, 2013 ATA System: 5311 SUBJECT: FUSELAGE - Frames and Bulkheads - Body Station (STA) 727 Bulkhead Lower Frame Web and Inner Chord - Inspection, Preventive Modification and Repair THIS BULLETIN 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 SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes This service bulletin is for the airplanes shown below. An equivalent change is on subsequent production airplanes. Refer to PRR 38275-185RS for data about this change. Refer to Service Bulletin Index D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. DESCRIPTIONCONFIGURATIONGROUP 737-600/700 airplane line numbers 1-1179, which have lower frame part numbers 144A2615-1 and 144A2615-2 installed, excluding airplane variable number YA026, YA035, YA036 and YA075, which had a repair installed in the left side of STA 727 bulkhead lower frame before the original issue of this service bulletin. -1 737-700 airplane variable number YA026, YA035 and YA036, which have lower frame part numbers 144A2615-1 and 144A2615-2 installed and that had a repair installed in the left side of STA 727 bulkhead lower frame before the original issue of this service bulletin. -2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 9 of 138 ### Page 10 DESCRIPTIONCONFIGURATIONGROUP 737-700 airplane variable number YA075, which has lower frame part numbers 144A2615-1 and 144A2615-2 installed and that had a repair, which is equivalent to Repair 1 in this service bulletin, installed in the left side of STA 727 bulkhead lower frame before the original issue of this service bulletin. -3 Airplane Models: 737-600, 737-700 GroupVariable Number 1YA001 - YA025 2YA026 1YA027 - YA034 2YA035 - YA036 1YA037 - YA074 3YA075 1YA076 - YA099 1YA101 - YA124 1YA201 - YA211 1YA231 - YA242 1YA251 - YA256 1YA271 - YA272 1YA291 1YA301 - YA302 1YA311 - YA314 1YA321 - YA323 1YA336 - YA344 1YA351 1YA356 - YA357 1YA366 - YA367 1YA501 - YA536 1YA541 - YA552 1YA571 - YA578 1YA601 - YA615 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 10 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 11 GroupVariable Number 1YA621 - YA622 1YA626 - YA629 1YA635 - YA636 1YA645 - YA647 1YA656 - YA659 1YA671 - YA672 1YA681 - YA691 1YA701 - YA706 1YA721 - YA722 1YA731 - YA734 1YA751 - YA756 1YA801 - YA803 1YA809 1YA811 - YA814 1YA831 - YA834 1YA841 - YA856 1YA881 - YA882 1YA891 - YA892 1YA961 - YA968 1YB001 - YB006 1YB101 - YB116 1YB151 - YB153 1YB161 - YB162 1YB171 - YB172 1YB181 - YB183 1YB201 - YB207 1YB271 1YB276 1YB301 - YB307 1YB501 - YB502 1YB521 1YB551 1YE001 - YE020 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 11 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 12 GroupVariable Number 1YE051 1YE101 - YE109 1YE151 - YE157 1YE171 - YE172 1YE201 - YE203 1YE301 - YE305 2. Spares Affected None. B. Concurrent Requirements None. C. Reason The inspections given in this service bulletin will detect cracks in the Body Station (STA) 727 bulkhead lower frame web and inner chord before they reach a critical length. The changes given in this service bulletin will decrease the occurrence of cracks at the STA 727 bulkhead lower frame web and inner chord. This area is a primary structural element (PSE). If the inspections given in this service bulletin are not accomplished undetected cracks could result in severed frames and induced skin cracks at these locations. This could lead to rapid decompression of the fuselage. The STA 727 bulkhead lower frames have been determined to be structure that is susceptible to Widespread Fatigue Damage (WFD). Boeing has received reports of cracking on four airplanes in the lower bulkhead frame as shown in the service history table below. Service History - Model 737-600/-700 ReportFlight Cycles/Flight- hours One crack extending 0.25 inches outboard from the fastener hole. (a)25,544/ 44,100 One crack extending 0.50 inches outboard from the fastener hole. (a)23,682/ 40,381 One crack extending 0.50 inch outboard from the fastener hole, and one crack extending inboard through the frame radius into the inner chord flange. (a) 25,616/ 44,061 One crack was found at a fastener in the STA 727 frame web at Left Buttock Line (LBL) 60. The crack measures 0.50 inch, extending inboard. (a) 25,435/43,543 (a) All cracks reported occur in the lower frame web and originates at the 5/16 Inch diameter fastener location adjacent to the inboard chord and common to the STA 727 bulkhead compression chord. 737-600/700 airplanes after line number 1179 have a different frame assembly installed in production that has a thicker web and chord in the areas prone to cracking. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 12 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 13 Airplanes variable number YA026, YA035, and YA036 had a repair installed in the left side STA 727 Bulkhead lower frame web before the original issue of this service bulletin. Airplane variable number YA075 had a repair, which is equivalent to Repair 1 in this service bulletin, installed in the left side STA 727 Bulkhead lower frame web before the original issue of this service bulletin. Boeing Service Related Problem (SRP) 737NG-53-0384 is related to this service bulletin. D. Description Group 1: Do detailed inspections on the left and right side, for cracking in the lower frame web and inner chord at STA 727, and an open hole high frequency eddy current (HFEC) inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable left or right side repair in accordance with this service bulletin. If a repair or modification is not installed, repeat the inspection. Group 2: Do detailed inspections on the right side only, for cracking in the lower frame web and inner chord at STA 727, and an open hole HFEC inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable right side repair in accordance with this service bulletin. If a repair or modification is not installed, repeat the inspection. Contact Boeing for left side inspection and modification instructions, and do the work instructed by Boeing. Group 3: Do detailed inspections on the right side, for cracking in the lower frame web and inner chord at STA 727, and an open hole HFEC inspection at one fastener location in the lower frame web adjacent to the inner chord. If any crack is found in the right lower frame web or inner chord that is greater than 1.50 inches and does not extend into the flange of the inner chord, contact Boeing to get repair instructions, and do the work instructed by Boeing. If any crack is found in the right lower frame web or inner chord that extends into the flange of the inner chord or is not greater than 1.50 inches, do the applicable right side repair in accordance with this service bulletin. If a repair or modification is not installed on the right side, repeat the inspection. Do a HFEC inspection for any cracking in the modified left lower frame web and inner chord at STA 727. If any crack is found on the lower frame web, contact Boeing for repair instructions and do the work instructed by Boeing. If no cracking is found on the left side, repeat the inspection. Group 1: Do post repair/post modification inspections on the left and right side, for cracks in the lower frame web and inner chord. If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 13 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 14 Group 2-3: Do post repair/post modification inspections on the right side only, for cracks in the lower frame web and inner chord. If any crack is found contact Boeing for the repair instructions and do the work instructed by Boeing. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 141, 142737-600, 737-700 Group 2-3: Affected Maintenance Zones ZoneModel 141, 142737-700 E. Compliance The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. For airplanes which have incorporated Boeing Business Jet (BBJ) Lower Cabin Altitude Supplemental Type Certificate (STC) ST01697SE (6500 feet maximum cabin altitude in lieu of 8000 feet) as referenced in Boeing SB 737-21-1149, the flight cycle related compliance times are different from those specified in this service bulletin. All initial compliance times (thresholds) specified in flight cycles must be reduced to half of those specified in this service bulletin. All repeat interval compliance times specified in flight cycles must be reduced to one-quarter of those specified in this service bulletin. Group 1: A logic diagram showing compliance tasks is included as an aid in APPENDIX A. Group 2: A logic diagram showing compliance tasks is included as an aid in APPENDIX B. Group 3: A logic diagram showing compliance tasks is included as an aid in APPENDIX C. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 14 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 15 Group 1: Table 1: Inspection, Repair, and Modification of the Left and Right side STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 4,500 flight cycles af- ter the original issue date of this service bul- letin. Before 19,000 total flight cycles Do a detailed inspection of the left and right side lower frame web and inner chord and an open hole HFEC inspection of the left and right side lower frame web in accordance with Para- graph 3.B., Work Instruc- tions, PART 2, step 1 All airplanes 6,000 flight cyclesWithin 6,000 flight cycles after the initial inspection. (a) Do a detailed inspection of the left and right side lower frame web and inner chord and an open hole HFEC inspection of the left and right side lower frame web in accordance with Para- graph 3.B., Work Instruc- tions, PART 2, step 1.j. No crack found on both the left and right sides (a) -Before further flight.Do the repair 1 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.a. Any crack found, on the left side, less than or equal to 0.18 inches -Before further flight.Do the repair 1 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.b. Any crack found, on the right side, less than or equal to 0.18 inches -Before further flight.Do the repair 2 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.c. Any crack found, on the left side, greater than 0.18 inches and less than or equal to 1.50 inches in length, that does not ex- tend into the flange of the inner chord -Before further flight.Do the repair 2 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.d. Any crack found, on the right side, greater than 0.18 inches and less than or equal to 1.50 inches in length, that does not ex- tend into the flange of the inner chord Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 15 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 16 Group 1: Table 1: Inspection, Repair, and Modification of the Left and Right side STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Before further flight.Do the repair 3 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.e. Any crack found, on the left side, greater than 0.18 inches, that extends into the flange of the inner chord -Before further flight.Do the repair 3 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 1.f. Any crack found, on the right side, greater than 0.18 inches, that extends into the flange of the inner chord -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boeing. Any crack found greater than 1.50 inches in length and does not extend into the flange of the inner chord (a)Before further flight.Do the preventive modifica- tion on the left side in ac- cordance with Paragraph 3.B., Work Instructions, PART 2, step 1.h. No crack found on the left side and a repair was ac- complished on the right side (a)Before further flight.Do the preventive modifica- tion on the right side in ac- cordance with Paragraph 3.B., Work Instructions, PART 2, step 1.i. No crack found on the right side and a repair was ac- complished on the left side (a) Accomplishment of a modification or repair in accordance with this service bulletin terminates the require- ment for repeat inspections. Post modification/repair inspections are provided in Table 4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 16 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 17 Group 2: Table 2: Inspection, Repair, and Modification of the Left and Right STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 4,500 flight cycles af- ter the original issue date of this service bul- letin. Before 19,000 total flight cycles Do a detailed inspection of the right side lower frame web and inner chord and an open hole HFEC inspec- tion of the right side lower frame web in accordance with Paragraph 3.B., Work Instructions, PART 2, step 2 All airplanes 6,000 flight cyclesWithin 6,000 flight cycles after the initial inspection. (a) Do a detailed inspection of the right side lower frame web and inner chord and an open hole HFEC inspec- tion of the right side lower frame web in accordance with Paragraph 3.B., Work Instructions, PART 2, step 2.e. No crack found on the right side (a) -Before further flight.Do the repair 1 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 2.a. Any crack found less than or equal to 0.18 inches -Before further flight.Do the repair 2 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 2.b. Any crack found greater than 0.18 inches and less than or equal to 1.50 inch- es in length, that does not extend into the flange of the inner chord -Before further flight.Do the repair 3 in accor- dance with Paragraph 3.B., Work Instructions, PART 2, step 2.c. Any crack found greater than 0.18 inches, that ex- tends into the flange of the inner chord -Before further flight.Contact Boeing for repair instructions and do the work instructed by Boeing. Any crack found greater than 1.50 inches in length and does not extend into the flange of the inner chord Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 17 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 18 Group 2: Table 2: Inspection, Repair, and Modification of the Left and Right STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 4,500 flight cycles af- ter the original issue date of this service bul- letin. Before 19,000 total flight cycles Contact Boeing for left side inspection and modification instructions and do the work instructed by Boeing. All airplanes (a) Accomplishment of a modification or repair in accordance with this service bulletin terminates the require- ment for repeat inspections. Post modification/repair inspections are provided in Table 5. Group 3: Table 3: Inspection, Repair, and Modification of the Right Side STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Within 4,500 flight cycles af- ter the original issue date of this service bul- letin. Before 19,000 to- tal flight cy- cles Do a detailed inspection of the right side lower frame web and inner chord and an open hole HFEC inspection of the right side lower frame web in accordance with Paragraph 3.B., Work Instruc- tions, PART 2, step 2 All airplanes 6,000 flight cy- cles Within 6,000 flight cycles af- ter the initial inspection. (a) Do a detailed inspection of the right side lower frame web and inner chord and an open hole HFEC inspection of the right side lower frame web in accordance with Paragraph 3.B., Work Instruc- tions, PART 2, step 2. No crack found (a) -Before further flight.Do the repair 1 in accordance with Paragraph 3.B., Work Instruc- tions, PART 2, step 2.a. Any crack found less than or equal to 0.18 inches -Before further flight.Do the repair 2 in accordance with Paragraph 3.B., Work Instruc- tions, PART 2, step 2.b. Any crack found greater than 0.18 inches and less than or equal to 1.50 inch- es in length, that does not extend into the flange of the inner chord -Before further flight.Do the repair 3 in accordance with Paragraph 3.B., Work Instruc- tions, PART 2, step 2.c. Any crack found greater than 0.18 inches, that ex- tends into the flange of in- ner chord Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 18 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 19 Group 3: Table 3: Inspection, Repair, and Modification of the Right Side STA 727 Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition -Before further flight.Contact Boeing for repair instruc- tions and do the work instructed by Boeing. Any crack found greater than 1.50 inches in length and does not extend into the flange of the inner chord (a) Accomplishment of a modification or repair in accordance with this service bulletin terminates the require- ment for repeat inspections. Post modification/repair inspections are provided in Table 6. Group 1: Table 4 - Post Modification/Repair Inspection of the Left and Right side Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance TimeActionCondition 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair. Do a HFEC inspection of the frame web and frame inner chord in accordance with Paragraph 3.B., Work Instructions, PART 4, step 2.a. Airplanes with the Repair 1 accomplished, on the left side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 4, step 2.b. 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the preventive modification. Do a HFEC inspection of the frame web and frame inner chord in accordance with Paragraph 3.B., Work Instructions, PART 4, step 5.a. Airplanes with the Preven- tive Modification accom- plished, on the left side, in accordance with this ser- vice bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the pre- ventive modification. Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 4, step 5.b. 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair. Do a HFEC inspection of the frame web and frame inner chord in accordance with Paragraph 3.B., Work Instructions, PART 5, step 2.a. Airplanes with the Repair 1 accomplished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 2.b. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 19 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 20 Group 1: Table 4 - Post Modification/Repair Inspection of the Left and Right side Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance TimeActionCondition 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the preventive modification Do a HFEC inspection of the frame web and frame inner chord in accordance with Paragraph 3.B., Work Instructions, PART 5, step 5.a. Airplanes with the Preven- tive Modification accom- plished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the pre- ventive modification Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 5.b. 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 4, step 3 Airplanes with Repair 2 accomplished, on the left side, in accordance with this service bulletin 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 3 Airplanes with Repair 2 accomplished, on the right side, in accordance with this service bulletin 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 4, step 4 Airplanes with Repair 3 accomplished, on the left side, in accordance with this service bulletin 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 4 Airplanes with Repair 3 accomplished, on the right side, in accordance with this service bulletin -Before further flight.Contact Boeing for repair instruc- tions and do the work instructed by Boeing. Any Crack found Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 20 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 21 Group 2: Table 5 - Post Modification/Repair Inspection of the Right side Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance TimeActionCondition 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair. Do a HFEC inspection of frame web and frame inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 2.a. Airplanes with the Repair 1 accomplished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 2.b. 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the preventive modification Do a HFEC inspection of frame web and frame inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 5.a. Airplanes with the Preven- tive Modification accom- plished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the pre- ventive modification Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 5.b. 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 3 Airplanes with Repair 2 accomplished, on the right side, in accordance with this service bulletin 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 4 Airplanes with Repair 3 accomplished, on the right side, in accordance with this service bulletin -Before further flight.Contact Boeing for repair instruc- tions and do the work instructed by Boeing. Any Crack found Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 21 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 22 Group 3: Table 6 - Post Modification/Repair Inspection of the Left and Right side Lower Frame Web and Inner Chord Repeat Interval (Not to Exceed) Compliance TimeActionCondition 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair (left side). Do a HFEC inspection of the left side frame web and frame inner chord in accordance with Para- graph 3.B., Work Instructions, PART 4, step 6.a. All airplanes 18,000 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair (left side). Do a HFEC inspection of the left side inner chord in accordance with Paragraph 3.B., Work Instruc- tions, PART 4, step 6.b. 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the repair. Do a HFEC inspection of frame web and frame inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 2.a. Airplanes with the Repair 1 accomplished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 2.b. 5,600 flight cy- cles Within 50,000 flight cycles after accomplishment of the preventive modification Do a HFEC inspection of frame web and frame inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 5.a. Airplanes with the Preven- tive Modification accom- plished, on the right side, in accordance with this service bulletin 18,000 flight cy- cles Within 50,000 flight cycles after installation of the pre- ventive modification Do a HFEC inspection of the inner chord in accordance with Para- graph 3.B., Work Instructions, PART 5, step 5.b. 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 3 Airplanes with Repair 2 accomplished, on the right side, in accordance with this service bulletin 8,000 flight cy- cles Within 50,000 flight cycles after installation of the repair. Do a HFEC inspection of the frame web and inner chord in ac- cordance with Paragraph 3.B., Work Instructions, PART 5, step 4 Airplanes with Repair 3 accomplished, on the right side, in accordance with this service bulletin -Before further flight.Contact Boeing for repair instruc- tions and do the work instructed by Boeing. Any Crack found Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 22 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 23 F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. G. Manpower The data below shows an estimate of the man hours necessary to do the inspection, repair, and preventive modification for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator man hour data if necessary. The estimate does not include lost time. These are some examples of lost time: — Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to make the parts — Time to find the tools. Group 1: INSPECTION AND PREVENTIVE MODIFICATION OR FRAME REPAIR - LEFT AND RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask 6.5013.002Open Access 5.3010.602FIGURE 1 4.258.502FIGURE 3 4.258.502FIGURE 4 5.50 (a)11.00 (a)2FIGURE 5 5.50 (a)11.00 (a)2FIGURE 6 5.25 (b)10.50 (b)2FIGURE 7 5.25 (b)10.50 (b)2FIGURE 8 5.25 (c)10.50 (c)2FIGURE 9 5.25 (c)10.50 (c)2FIGURE 10 6.5013.002Close Access 26.8053.60TOTAL FOR EACH AIRPLANE (a) Add time to total if crack is found and repair 1 is accomplished. (b) Add time to total if crack is found and repair 2 is accomplished. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 23 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 24 Group 1: INSPECTION AND PREVENTIVE MODIFICATION OR FRAME REPAIR - LEFT AND RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask (c) Add time to total if crack is found and repair 3 is accomplished. Group 2: INSPECTION AND PREVENTIVE MODIFICATION OR FRAME REPAIR - RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask 3.507.002Open Access 5.3010.602FIGURE 2 4.258.502FIGURE 4 5.50 (a)11.00 (a)2FIGURE 6 5.25 (b)10.50 (b)2FIGURE 8 5.25 (c)10.50 (c)2FIGURE 10 3.507.002Close Access 16.5533.10TOTAL FOR EACH AIRPLANE (a) Add time to total if crack is found and repair 1 is accomplished. (b) Add time to total if crack is found and repair 2 is accomplished. (c) Add time to total if crack is found and repair 3 is accomplished. Group 3: INSPECTION AND PREVENTIVE MODIFICATION OR FRAME REPAIR - LEFT AND RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask 3.507.002Open Access 5.3010.602FIGURE 2 4.258.502FIGURE 4 5.50 (a)11.00 (a)2FIGURE 6 5.25 (b)10.50 (b)2FIGURE 8 5.25 (c)10.50 (c)2FIGURE 10 2.152.151FIGURE 11 3.507.002Close Access 20.0535.25TOTAL FOR EACH AIRPLANE (a) Add time to total if crack is found and repair 1 is accomplished. (b) Add time to total if crack is found and repair 2 is accomplished. (c) Add time to total if crack is found and repair 3 is accomplished. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 24 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 25 Group 1: POST MODIFICATION OR REPAIR INSPECTIONS - LEFT AND RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask 1.301.301Open Access 2.152.151FIGURE 11 2.152.151FIGURE 12 2.152.151FIGURE 13 2.152.151FIGURE 14 2.152.151FIGURE 15 2.152.151FIGURE 16 1.301.301Close Access 15.5015.50TOTAL FOR EACH AIRPLANE Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 25 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 26 Group 2-3: POST MODIFICATION OR REPAIR INSPECTIONS - RIGHT SIDE Elapsed HoursTask-HoursNumber of PersonsTask 1.301.301Open Access 2.152.151FIGURE 12 2.152.151FIGURE 14 2.152.151FIGURE 16 1.301.301Close Access 9.059.05TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes 737-600/700 Airplanes Change in Moment (Pound-Inches) Change in Weight (Pounds) Task +521.0+0.7168Preventive Modification/Frame Repair 1 - left side +1,534.0+2.1106Frame Repair 2 - left side +1,640.0+2.2563Frame Repair 3 - left side +521.0+0.7168Preventive Modification/Frame Repair 1 - right side +1,534.0+2.1106Frame Repair 2 - right side +1,640.0+2.2563Frame Repair 3 - right side I. Electrical Load Data Not applicable J. References 1. Existing Data: a. Engineering Change Memo PRR 38275-185RS. b. Boeing Service Bulletin 737-21-1149. c. Boeing Service Related Problem (SRP) 737NG-53-0384. d. Service Bulletin Index D6-19567. e. Standard Overhaul Practices Manual (SOPM) 20-41-02, 20-43-03, 20-50-19. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 26 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 27 f. 737 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00 Procedure 4, Procedure 11, Procedure 16, Procedure 23. g. 737-600/700/800/900 Aircraft Maintenance Manual (AMM) 06-30-00, 24-22-00, 25-52-06, 25-52-18, 25-80-00, 26-21-01, 32-00-01. h. 737-600 Structural Repair Manual (SRM) 51-20-10, 51-30-01. i. 737-700 Structural Repair Manual (SRM) 51-20-10, 51-30-01. 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number BULKHEAD INSTL - STA 727.00144A2600 FRAME ASSEMBLY - LOWER, STA 727.00, BULKHEAD144A2604 FRAME - LOWER, STA 727.00, BULKHEAD144A2615 DETAILS - BLKHD STA 727144A2619 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. K. Publications Affected 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. M. Software Accomplishment Summary Not affected. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 27 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 28 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 28 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT BLANK PAGE ### Page 29 2. MATERIAL INFORMATION A. Material - Price and Availability Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane, and Paragraph 2.D., Parts Necessary to Change Spares. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price Jan 31/2012 (US Dollars) ROLT (days)NameTop Kit $1,132.00543Top Kit, Retrofit - Preventive Modification/Frame Repair 1 - Left Side 002A0003-161 2,183.00543Top Kit, Retrofit - Frame Repair 2 - Left Side002A0003-162 2,820.00543Top Kit, Retrofit - Frame Repair 3 - Left Side002A0003-163 1,132.00543Top Kit, Retrofit - Preventive Modification/Frame Repair 1 - Right Side 002A0003-203 2,183.00543Top Kit, Retrofit - Frame Repair 2 - Right Side002A0003-204 2,820.00543Top Kit, Retrofit - Frame Repair 3 - Right Side002A0003-205 B. Industry Support Information Boeing warranty remedies are available for 737 airplanes in warranty as of June 2, 2011. For task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. The kits for airplanes in warranty as of that date will be supplied at no charge. Send a purchase order for the kits to Boeing Spares. Please refer to this service bulletin number and reference the airplane variables in your purchase order. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 29 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 30 C. Parts Necessary for Each Airplane 1. Kits/Parts: To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. NOTE: Group 1: One Top Kit for the left side, one top kit for the right side, and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. Group 2-3: One Top Kit for the right side and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. Group 1: Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -163-162-161 Top Kit, Retrofit - Preventive Modifica- tion/Frame Repair 1 - Left Side ..-002A0003-161 Top Kit, Retrofit - Frame Repair 2 - Left Side .-.002A0003-162 Top Kit, Retrofit - Frame Repair 3 - Left Side -..002A0003-163 (a) (c) (e) 144A2619-7ANGLE - RETROFIT..1144A2619-21 (b) (e)STRAP - RETROFIT..1144A2619-23 (b) (e)STRAP - RETROFIT.1.144A2619-24 (a) (c) (e) 144A2619-7ANGLE - RETROFIT.1.144A2619-25 (b) (e)FITTING - RETROFIT.1.144A2619-27 (b) (e)SPLICE STRAP - RETROFIT11.144A2619-29 (b) (e)FILLER - RETROFIT.1.144A2619-30 (a) (c) (e) 144A2619-7ANGLE - RETROFIT1..144A2619-31 (b) (e)STRAP - RETROFIT1..144A2619-33 (b) (e)FITTING - RETROFIT1..144A2619-35 (b) (e)FILLER - RETROFIT1..144A2619-37 (d)HEX DRIVE BOLT.1.BACB30NX10K10 (d)BOLT2..BACB30NX10K7 (d)BOLT, PROTRUDING HD..1BACB30NX10K8X Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 30 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 31 Group 1: Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -163-162-161 (d)BOLT, PROTRUDING HD12.BACB30NX10K9 (d)BOLT, PROTRUDING HD1BACB30NX12K7 (d)HEX DRIVE BOLT15.BACB30NX8K10 (d)BOLT, PROTRUDING HD222BACB30NX8K11 (d)BOLT, PROTRUDING HD1..BACB30NX8K12 (d)HI LOK559BACB30NX8K5 (d)BOLT656BACB30NX8K6 (d)BOLT, HEX DRIVE865BACB30NX8K7 (d)BOLT211BACB30NX8K8 (d)HEX DRIVE BOLT346BACB30NX8K9 (d)BOLT242BACB30VT8K10 (d)BOLT1212.BACB30VT8K4 (d)BOLT665BACB30VT8K5 (d)HI-LOK.2.BACB30VT8K6 (d)BOLT.2.BACB30VT8K7 (d)BOLT SHEAR LIGHT832BACB30VT8K8 (d)BOLT HI-LOK232BACB30VT8K9 COLLAR303211BACC30BL8 (b)FILLER1..BACF3F008E017NN (b)FILLER, RECTANGULAR1..BACF3H06YK018HN (b)FILLER-RADIUS.1.BACF3H07JP008HN (b)FILLER, RECTANGULAR.1.BACF3H07JP037HN (b)FILLER, RECTANGULAR..1BACF3H12JP013HN NUT, SELF-LOCK, HEX262627BACN10YT4CD NUT, SELF-LOCK, HEX331BACN10YT5CD NUT, SELF-LOCK, HEX..1BACN10YT6CD NUT ASSEMBLY222BACN11E4 (a) Discard the existing part. (b) This part is not used in production. (c) You cannot use the existing part to replace the new or changed part. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 31 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 32 Group 1: Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -163-162-161 (d) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. (e) To make installation easier, some Boeing parts are sent in an 'interim' configuration. Boeing will identify these interim configurations with a 'U', 'W' or 'Y' in place of the '-' (dash) in the part number. Interim parts are changed to the 'dash' configuration when installed as given in the Accomplishment Instructions of this service bulletin. Refer to Boeing Drawing 005W0900 "INTERIM PARTS - SPARES" and Boeing Service Letter 737-SL-00-018 for more information. Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -205-204-203 Top Kit, Retrofit - Preventive Modifica- tion/Frame Repair 1 - Right Side ..-002A0003-203 Top Kit, Retrofit - Frame Repair 2 - Right Side .-.002A0003-204 Top Kit, Retrofit - Frame Repair 3 - Right Side -..002A0003-205 (a) (c) (e) 144A2619-8ANGLE - RETROFIT..1144A2619-22 (b) (e)STRAP - RETROFIT..1144A2619-23 (b) (e)STRAP - RETROFIT.1.144A2619-24 (a) (c) (e) 144A2619-8ANGLE - RETROFIT.1.144A2619-26 (b) (e)FITTING - RETROFIT.1.144A2619-28 (b) (e)SPLICE STRAP - RETROFIT11.144A2619-29 (b) (e)FILLER - RETROFIT.1.144A2619-30 (a) (c) (e) 144A2619-8ANGLE - RETROFIT1..144A2619-32 (b) (e)STRAP - RETROFIT1..144A2619-33 (b) (e)FITTING - RETROFIT1..144A2619-36 (b) (e)FILLER - RETROFIT1..144A2619-37 (d)HEX DRIVE BOLT.1.BACB30NX10K10 (d)BOLT2..BACB30NX10K7 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 32 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 33 Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -205-204-203 (d)BOLT, PROTRUDING HD..1BACB30NX10K8X (d)BOLT, PROTRUDING HD12.BACB30NX10K9 (d)BOLT, PROTRUDING HD1BACB30NX12K7 (d)HEX DRIVE BOLT15.BACB30NX8K10 (d)BOLT, PROTRUDING HD222BACB30NX8K11 (d)BOLT, PROTRUDING HD1..BACB30NX8K12 (d)HI LOK559BACB30NX8K5 (d)BOLT656BACB30NX8K6 (d)BOLT, HEX DRIVE865BACB30NX8K7 (d)BOLT211BACB30NX8K8 (d)HEX DRIVE BOLT346BACB30NX8K9 (d)BOLT242BACB30VT8K10 (d)BOLT1212.BACB30VT8K4 (d)BOLT665BACB30VT8K5 (d)HI-LOK.2.BACB30VT8K6 (d)BOLT.2.BACB30VT8K7 (d)BOLT SHEAR LIGHT832BACB30VT8K8 (d)BOLT HI-LOK232BACB30VT8K9 COLLAR303211BACC30BL8 (b)FILLER1..BACF3F008E017NN (b)FILLER, RECTANGULAR1..BACF3H06YK018HN (b)FILLER-RADIUS.1.BACF3H07JP008HN (b)FILLER, RECTANGULAR.1.BACF3H07JP037HN (b)FILLER, RECTANGULAR..1BACF3H12JP013HN NUT, SELF-LOCK, HEX262627BACN10YT4CD NUT, SELF-LOCK, HEX331BACN10YT5CD NUT, SELF-LOCK, HEX..1BACN10YT6CD NUT ASSEMBLY222BACN11E4 (a) Discard the existing part. (b) This part is not used in production. (c) You cannot use the existing part to replace the new or changed part. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 33 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 34 Kit 002A0003 NotesExisting Part Number NameQTYNew Part Number -205-204-203 (d) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. (e) To make installation easier, some Boeing parts are sent in an 'interim' configuration. Boeing will identify these interim configurations with a 'U', 'W' or 'Y' in place of the '-' (dash) in the part number. Interim parts are changed to the 'dash' configuration when installed as given in the Accomplishment Instructions of this service bulletin. Refer to Boeing Drawing 005W0900 "INTERIM PARTS - SPARES" and Boeing Service Letter 737-SL-00-018 for more information. 2. Parts and Materials Supplied by the Operator: The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available. NotesNameQTYPart Number / Specification (a)SEALANT-BMS 5-95 TYPE 1, Class B (a)PRIMER-BMS 10-11, Type 1 (b)CHEMICAL CONVERSION COATING-TYPE 2, CLASS A FILLER A27075-T6 PER AMS-QQ-A-250/12 7075-T6 CLAD PER AMS-QQ-A-250/13 (1.25 x 2.5 x 0.12 inch) BOLT, PROTRUDING HD2BACB30NX10K7X NUT, SELF-LOCK, HEX2BACN10YT5CD (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to Boeing SOPM 20-43-03 or 737 SRM, Chapter 51, for supplier data. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 34 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 35 F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 35 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 36 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 36 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT BLANK PAGE ### Page 37 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – 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 737 Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in 737 SRM Chapter 51 4. Use the approved fastener and process material substitutions in accordance with 737 SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in 737 SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in 737 SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with 737 SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. 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. 8. 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 37 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 38 9. Refer to APPENDIX A, APPENDIX B and APPENDIX C for logic diagrams. Logic diagrams are provided as an aid only. Information contained in Paragraph 1.E., Compliance is the primary source for compliance times. Information in Paragraph 3.B., Work Instructions is the primary source for tasks required for compliance. 10. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 11. 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. 12. 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. 13. Shaded areas in Figures are reference only. Shaded areas in Figures may look different than your airplane. B. WORK INSTRUCTIONS PART 1 - GET ACCESS 1. Remove and keep aft cargo compartment forward bulkhead liner and cargo compartment sidewall lining for access to the lower frame web assembly. Refer to 737-600/700/800/900 AMM 06-30-00 and 737-600/700/800/900 AMM 25-80-00 as an accepted procedure. Panel Number737 AMM SubjectEquipment 141LW, 141JW, and 142MW 737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner 142AW737-600/700/800/900 AMM 25-52-06Cargo Compartment Sidewall Lining -737-600/700/800/900 AMM 25-80-00Insulation Blankets 2. Get access to the left main wheel well in the aft bulkhead area as follows: a. Install landing gear downlock pins. Refer to 737-600/700/800/900 AMM 32-00-01 as an accepted procedure. b. Remove electrical power from the airplane. Refer to 737-600/700/800/900 AMM 24-22-00 as an accepted procedure. c. Get access to the left main wheel well in the aft bulkhead area. 3. Get access to the right main wheel well in the aft bulkhead area as follows: a. Install landing gear downlock pins. Refer to 737-600/700/800/900 AMM 32-00-01 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 38 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 39 b. Remove electrical power from the airplane. Refer to 737-600/700/800/900 AMM 24-22-00 as an accepted procedure. c. Remove Fire Extinguisher Bottles. Refer to 737-600/700/800/900 AMM 26-21-01 as an accepted procedure. d. Get access to the right main wheel well in the aft bulkhead area. PART 2 - INSPECTION AND PREVENTIVE MODIFICATION OR FRAME REPAIR 1. Group 1: Do a detailed inspection of the left and right side lower frame web and inner chord and an open hole high frequency eddy current (HFEC) inspection of the left and right side lower frame web in accordance with FIGURE 1. a. If any crack is found on the left side not more than 0.18 inches in length, do repair 1 in accordance with FIGURE 5. b. If any crack is found on the right side not more than 0.18 inches in length, do repair 1 in accordance with FIGURE 6. c. If any crack is found on the left side more than 0.18 inches and less than or equal to 1.50 inches in length and does not extend into the flange of the inner chord, do repair 2 in accordance with FIGURE 7. d. If any crack is found on the right side more than 0.18 inches and less than or equal to 1.50 inches in length and does not extend into the flange of the inner chord, do repair 2 in accordance with FIGURE 8. e. If any crack is found on the left side more than 0.18 inches in length and extends into the flange of the inner chord, do repair 3 in accordance with FIGURE 9. f. If any crack is found on the right side more than 0.18 inches in length and extends into the flange of the inner chord, do repair 3 in accordance with FIGURE 10. g. If any crack is found more than 1.50 inches in length and does not extend into the flange of the inner chord contact Boeing for repair instructions and do the work instructed by Boeing. h. If no crack was found on the left side and a repair was accomplished on the right side, do the preventive modification on the left side in accordance with FIGURE 3. i. If no crack was found on the right side and a repair was accomplished on the left side, do the preventive modification on the right side in accordance with FIGURE 4. j. If no crack is found on both the left and right sides, install replacement fasteners in accordance with FIGURE 1 and repeat inspections at the times given in Paragraph 1.E., Compliance. OR do the preventive modification in accordance with FIGURE 3 and FIGURE 4. NOTE: Post modification inspections are provided in Paragraph 1.E., Compliance, Table 4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 39 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 40 2. Group 2-3: Do a detailed inspection of the right side lower frame web and inner chord and an open hole HFEC inspection of the right side lower frame web in accordance with FIGURE 2. a. If any crack is found on the right side not more than 0.18 inches in length, do repair 1 in accordance with FIGURE 6. b. If any crack is found on the right side not more than 0.18 inches and less than or equal to 1.50 inches in length and does not extend into the flange of the inner chord, do repair 2 in accordance with FIGURE 8. c. If any crack is found on the right side more than 0.18 inches in length and extends into the flange of the inner chord, do repair 3 in accordance with FIGURE 10. d. If any crack is found more than 1.50 inches in length and does not extend into the flange of the inner chord contact Boeing for repair instructions and do the work instructed by Boeing. e. If no crack is found on the right side, install a replacement fastener in accordance with FIGURE 2 and repeat inspections at the times given in Paragraph 1.E., Compliance. OR do the preventive modification on the right side in accordance with FIGURE 4. Group 2: NOTE: Post modification inspections are provided in Paragraph 1.E., Compliance, Table 5. Group 3: NOTE: Post modification inspections are provided in Paragraph 1.E., Compliance, Table 6. 3. Group 2: Contact Boeing for left side inspection and modification instruction and do the work instructed by Boeing. PART 3 - RESTORE ACCESS 1. Close access to the left main wheel well in the aft bulkhead area: a. Restore the electrical power to the airplane. Refer to 737-600/700/800/900 AMM 24-22-00, as an accepted procedure. b. Remove downlock pins from all landing gears. Refer to 737-600/700/800/900 AMM 32-00-01 as an accepted procedure. 2. Close access to the right main wheel well in the aft bulkhead area: a. Restore Fire Extinguisher Bottles. Refer to 737-600/700/800/900 AMM 26-21-01 as an accepted procedure. b. Restore the electrical power to the airplane. Refer to 737-600/700/800/900 AMM 24-22-00, as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 40 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 41 c. Remove downlock pins from all landing gears. Refer to 737-600/700/800/900 AMM 32-00-01 as an accepted procedure. 3. Close access to aft cargo compartment forward bulkhead liner, cargo compartment sidewall lining for access to the lower frame web assembly. Refer to 737-600/700/800/900 AMM 06-30-00 and 737-600/700/800/900 AMM 25-80-00 as an accepted procedure. Panel Number737 AMM SubjectEquipment 141LW, 141JW, and 142MW 737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner 142AW737-600/700/800/900 AMM 25-52-06Cargo Compartment Sidewall Lining -737-600/700/800/900 AMM 25-80-00Insulation Blankets 4. Return the airplane to a serviceable condition. Group 1, 3: PART 4 - POST MODIFICATION/REPAIR INSPECTION OF THE LEFT SIDE 1. Remove aft cargo compartment forward bulkhead liners, and insulation blankets to get access to the lower frame web and inner chord. Refer to 737-600/700/800/900 AMM 25-52-18 and 737-600/700/800/900 AMM 25-80-00 as an accepted procedure. Panel Number737 AMM SubjectEquipment 141LW, 141JW737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner -737-600/700/800/900 AMM 25-80-00Insulation Blankets 2. Group 1: Frame Web and Inner Chord Inspection - airplanes with repair 1 installed: a. Do a HFEC inspection of the left STA 727 lower frame web and frame inner chord in accordance with FIGURE 11, step 1 and step 2. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. b. Do a HFEC inspection of the left STA 727 frame inner chord in accordance with FIGURE 11, step 3. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 3. Group 1: Frame Web and Inner Chord Inspection - airplanes with repair 2 installed: a. Do a HFEC inspection of the left STA 727 lower frame web and inner chord in accordance with FIGURE 13. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 41 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 42 (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 4. Group 1: Frame Web and Inner Chord Inspection - airplanes with repair 3 installed: a. Do a HFEC inspection of the left STA 727 lower frame web and inner chord in accordance with FIGURE 15. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 5. Group 1: Frame Web and Inner Chord Inspection - airplanes with preventive modification installed: a. Do a HFEC inspection of the left STA 727 lower frame web and frame inner chord in accordance with FIGURE 17, step 1 and step 2. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. b. Do a HFEC inspection of the left STA 727 frame inner chord in accordance with FIGURE 17, step 3. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 6. Group 3: Frame Web and Inner Chord Inspection: a. Do a HFEC inspection of the left STA 727 lower frame web and frame inner chord in accordance with FIGURE 11, step 1 and step 2. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. b. Do a HFEC inspection of the left STA 727 frame inner chord in accordance with FIGURE 11, step 3. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 7. Restore/Install aft cargo compartment forward bulkhead liners, and insulation blankets. Refer to 737-600/700/800/900 AMM 25-52-18 and 737-600/700/800/900 AMM 25-80-00 as an accepted procedure. Panel Number737 AMM SubjectEquipment 141LW, 141JW737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner -737-600/700/800/900 AMM 25-80-00Insulation Blankets Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 42 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 43 8. Put the airplane back to a serviceable condition. PART 5 - POST MODIFICATION/REPAIR INSPECTION OF THE RIGHT SIDE 1. Remove aft cargo compartment forward bulkhead liner, sidewall lining, and insulation blankets to get access to the lower frame web and inner chord. Refer to 737-600/700/800/900 AMM 25-52-18, 737-600/700/800/900 AMM 25-52-06 and 737-600/700/800/900 AMM 25-80-00 as an accepted procedure. Panel Number737AMM SubjectEquipment 142MW737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner 142AW737-600/700/800/900 AMM 25-52-06Cargo Compartment Sidewall Lining -737-600/700/800/900 AMM 25-80-00Insulation Blankets 2. Frame Web and Inner Chord Inspection - airplanes with repair 1 installed: a. Do a HFEC inspection of the right STA 727 lower frame web and frame inner chord in accordance with FIGURE 12, step 1 and step 2. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. b. Do a HFEC inspection of the right STA 727 frame inner chord in accordance with FIGURE 12, step 3. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 3. Frame Web and Inner Chord Inspection - airplanes with repair 2 installed: a. Do a HFEC inspection of the right STA 727 lower frame web and inner chord in accordance with FIGURE 14. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 4. Frame Web and Inner Chord Inspection - airplanes with repair 3 installed: a. Do a HFEC inspection of the right STA 727 lower frame web and inner chord in accordance with FIGURE 16. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 5. Frame Web and Inner Chord Inspection - airplanes with preventive modification installed: a. Do a HFEC inspection of the right STA 727 lower frame web and frame inner chord in accordance with FIGURE 18, step 1 and step 2. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 43 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 44 (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. b. Do a HFEC inspection of the right STA 727 frame inner chord in accordance with FIGURE 18, step 3. (1) If any crack is found, contact Boeing for repair instructions and do the work instructed by Boeing. 6. Restore/Install aft cargo compartment forward bulkhead liner, sidewall lining, and insulation blankets. Refer to 737-600/700/800/900 AMM 25-52-18 and 737-600/700/800/900 AMM 25-52-06 as an accepted procedure. Panel Number737 AMM SubjectEquipment 142MW737-600/700/800/900 AMM 25-52-18Aft Cargo Compartment Forward Bulk- head Liner 142AW737-600/700/800/900 AMM 25-52-06Cargo Compartment Sidewall Lining -737-600/700/800/900 AMM 25-80-00Insulation Blankets 7. Put the airplane back to a serviceable condition. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 44 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 45 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT This Figure applies only to: Group 1. STA 727 SIA 727 2177651 FIGURE 1: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - LEFT AND RIGHT SIDE (SHEET 1 OF 4) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 138 ### Page 46 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT 23AG0 LOWER EXAMPLE CRACK FRAME FWD DETAILED INSPECTION INBD 2178660 AREA FIGURE 1: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - LEFTI AND RIGHT SIDE (SHEET 2 OF 4) Original Issue: December 03, 2013 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1325 Work - See page 1 for details. 46 of 138 ### Page 47 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT LOWER 23450 FRAME EXAMPLE CRACK FWD DETAILED INSPECTION NBD 2178718 AREA FIGURE 1: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - LEFT AND RIGHT SIDE (SHEET 3 OF 4) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 138 ### Page 48 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each side of the airplane. More DataQtyIdentificationNameTaskStep (a)--LOWER FRAME WEBInspect1 (a)--INNER CHORDInspect 1-FASTENERRemove2 (b)1-LOWER FRAME WEBInspect3 (c) (d)1-LOWER FRAME WEBDrill / Ream4 (c) (d) (e) (f)1BACB30NX10K7XBOLT, PROTRUDING HD Install (New)5 1BACN10YT5CDNUT, SELF-LOCK, HEX Install (New) Brush coat fastener heads, collars, and nuts. (g) -BMS 5-95SEALANTApply6 (a) Do a Detailed Inspection for cracking in the indicated area. (b) Do an open hole HFEC inspection for cracking in accordance with 737 NDT Part 6, 51-00-00, Procedure 11 or Procedure 16, 0.03 notch standard. (c) Only necessary if no cracks are found and the preventive modification is not being accomplished. (d) Hole diameter 0.3231 - 0.3261 inches. (e) Install wet using BMS 5-95. (f) Torque to 150 - 200 inch-pounds. (g) Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 1: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - LEFT AND RIGHT SIDE (SHEET 4 OF 4) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 48 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 49 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT This Figure applies only to: Group 2-3. STA 727 STA 727 2191948 FIGURE 2: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - RIGHT SIDE (SHEET 1 OF 3) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 138 ### Page 50 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT LOWER 234€6 FRAME EXAMPLE CRACK FWD DETAILED INSPECTION 2191949 AREA FIGURE 2: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - RIGHT SIDE (SHEET 2 OF 3) Original Issue: December 03, 2013 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1325 Work - See page 1 for details. 50 of 138 ### Page 51 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure. More DataQtyIdentificationNameTaskStep (a)--LOWER FRAME WEBInspect1 (a)--INNER CHORDInspect 1-FASTENERRemove2 (b)1-LOWER FRAME WEBInspect3 (c) (d)1-LOWER FRAME WEBDrill / Ream4 (c) (d) (e) (f)1BACB30NX10K7XBOLT, PROTRUDING HD Install (New)5 1BACN10YT5CDNUT, SELF-LOCK, HEX Install (New) Brush coat fastener heads, collars, and nuts. (g) -BMS 5-95SEALANTApply6 (a) Do a Detailed Inspection for cracking in the indicated area. (b) Do an open hole HFEC inspection for cracking in accordance with 737 NDT Part 6, 51-00-00, Procedure 11 or Procedure 16, 0.03 notch standard. (c) Only necessary if no cracks are found and the preventive modification is not being accomplished. (d) Hole diameter 0.3231 - 0.3261 inches. (e) Install wet using BMS 5-95. (f) Torque to 150 - 200 inch-pounds. (g) Refer to SOPM 20-50-19 as an accepted procedure. FIGURE 2: BODY STATION (STA) 727 LOWER FRAME WEB AND INNER CHORD - INSPECTION - RIGHT SIDE (SHEET 3 OF 3) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 51 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 52 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT This Figure applies only to: Group 1. STA 727 2177678 FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE (SHEET 1 OF 5) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 138 ### Page 53 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT LOWER FRAME FWD INBD BEFORE B-B 2179027 A-A FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE (SHEET 2 OF 5) Original Issue: December 03, 2013 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1325 Work - See page 1 for details. 53 of 138 ### Page 54 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT STRAP 160€ - RETROFIT - 4) 6 5.43 2.00 CHORD _D LOWER FRAME D ANGLE 15 - RETROFIT 10 WD INBD AFTER A-A C-C 2179051 FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE (SHEET 3 OF 5) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-53A1325 Work - See page 1 for details. 54 of 138 ### Page 55 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 one side of the airplane. More DataQtyIdentificationNameTaskStep (a)1144A2619-7ANGLERemove1 --FASTENERRemove (a)1-LOWER FRAMEClean2 Make sure each at- tachment is aligned to the lower frame web. 1144A2619-23STRAP - RETROFITLocate3 1144A2619-21ANGLE - RETROFITLocate (d) (e)1144A2619-21ANGLE - RETROFITDrill4 (d) (e)1144A2619-23STRAP - RETROFITDrill (d) (e)--LOWER FRAMEDrill to the mating sur- faces of the strap and frame. (b) -BMS 5-95SEALANTApply5 (c)1144A2619-21ANGLE - RETROFITInstall (New)6 (c)1144A2619-23STRAP - RETROFITInstall (New) --FASTENERInstall (New) Brush coat fastener heads, collars, and nuts. (b) -BMS 5-95SEALANTApply7 (a) Clean all sealant material from mating surfaces. (b) Refer to SOPM 20-50-19 as an accepted procedure. (c) Install all fasteners wet with BMS 5-95. (d) See fastener code table for holes sizes. (e) Match drill the strap and angle from existing fastener holes in the lower frame web. Drill additional fastener holes from pilots in new parts. FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE (SHEET 4 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 55 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT ### Page 56 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT FASTENER DIAMETER (OPTIONAL) LETTER CODE HEAD LOCATION N = NEAR SIDE D 6F F = FAR SIDE (OPTIONAL) C COUNTERSINK FASTENER LENGTH/GRIP (OPTIONAL) EXAMPLE OF FASTENER SYMBOL 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. Code Name Identification Qty Hole Dia More Data HI LOK BACB30NX8K5 9 0.247 - 0.250 (a) BOLT BACB30NX8K6 6 0.247 - 0.250 (a) BOLT, HEX DRIVE BACB30NX8K7 5 0.247 - 0.250 (a) BOLT BACB30NX8K8 1 0.247 - 0.250 (a) HEX DRIVE BOLT BACB30NX8K9 6 0.247 - 0.250 (a) NUT, SELF-LOCK, HEX BACN10YT4CD 27 BOLT, PROTRUDING HD BACB30NX8K11 2 0.247 - 0.250 (a) NUT ASSEMBLY BACN11E4 2 C BOLT, PROTRUDING HD BACB30NX12K7 0.370 - 0.373 NUT, SELF-LOCK, HEX BACN10YT6CD 1 D BOLT BACB30VT8K5 5 0.247 - 0.250 (a) BOLT SHEAR LIGHT BACB30VT8K8 2 0.247 - 0.250 (a) BOLT HI-LOK BACB30VT8K9 2 0.247 - 0.250 (a) BOLT BACB30VT8K10 2 0.247 - 0.250 (a) COLLAR BACC30BL8 11 (a) f necessary, oversize fastener hole diameter by 1/64 inch and install a 1/64 inch oversize fastener. FIGURE 3: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - LEFT SIDE (SHEET 5 OF 5) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-53A1325 Work - See page 1 for details. 56 of 138 ### Page 57 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT SIA 727 STA 727 2180986 FIGURE 4: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - RIGHT SIDE (SHEET 1 OF 5) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 138 ### Page 58 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT LOWEF - RAME FWD INBD BEFORE B-B 2180987 A-A FIGURE 4: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - RIGHT SIDE (SHEET 2 OF 5) Original Issue: December 03, 2013 Export Controlled ECCN: 9E991 - BOEING 737-53A1325 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 138 ### Page 59 (OCR) BOEING SERVICE BULLETIN 737-53A1325 ALERT ALERT STRAP -RETROFIT (3)4) 5)6) 5. i.43 CHORD LOWER FRAME ANGLE - RETROFIT AFTER A-A INBD C-C 2181166 FIGURE 4: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - RIGHT SIDE (SHEET 3 OF 5) Original Issue: December 03, 2013 PROPRIETARY - Copyright ® Unpublished Export Controlled ECCN: 9E991 - BOEING 737-53A1325 Work - See page 1 for details. 59 of 138 ### Page 60 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 one side of the airplane. More DataQtyIdentificationNameTaskStep (a)1144A2619-8ANGLERemove1 --FASTENERRemove (a)1-LOWER FRAMEClean2 Make sure each at- tachment is aligned to the lower frame web. 1144A2619-23STRAP - RETROFITLocate3 1144A2619-22ANGLE - RETROFITLocate (d) (e)1144A2619-22ANGLE - RETROFITDrill4 (d) (e)1144A2619-23STRAP - RETROFITDrill (d) (e)--LOWER FRAMEDrill to the mating sur- faces of the strap and frame. (b) -BMS 5-95SEALANTApply5 (c)1144A2619-22ANGLE - RETROFITInstall (New)6 (c)1144A2619-23STRAP - RETROFITInstall (New) 1-FASTENERInstall (New) Brush coat fastener heads, collars, and nuts. (b) -BMS 5-95SEALANTApply7 (a) Clean all sealant material from mating surfaces. (b) Refer to SOPM 20-50-19 as an accepted procedure. (c) Install all fasteners wet with BMS 5-95. (d) See fastener code table for holes sizes. (e) Match drill the strap and angle from existing fastener holes in the lower frame web. Drill additional fastener holes from pilots in new parts. FIGURE 4: BODY STATION (STA) 727 LOWER FRAME PREVENTIVE MODIFICATION - RIGHT SIDE (SHEET 4 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 03, 2013 737-53A1325 60 of 138 BOEING SERVICE BULLETIN 737-53A1325 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/737-53a1325/file/810d1c96a56b.md?from=61 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.