# Boeing Service Bulletin A3183: Revision 6 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2014-0756; AD 2015-11-04 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Service Bulletin A3183](https://openairdocs.org/service-documents/boeing/a3183.md) - Title as filed: U.S. DOT/FAA - Service Bulletin 707-00A3183-06 - Pages: 106 - PDF: https://openairdocs.org/files/sha256/b4/4f/b44fc7db2675659669f7dab444875abef80d93cad0a92162e6c609d9917027e9 - Page: https://openairdocs.org/service-documents/boeing/a3183/file/b44fc7db2675 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 707 Service Bulletin ALERT Number: A3183 Original Issue: June 27, 1975 Revision 6: February 07, 2014 ATA System: 5410 SUBJECT: NACELLE - Inboard and Outboard Nacelle Strut - Midspar Fitting - Inspection and Replacement 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 © 1989 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 Unpublished Work.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: June 27, 1975 A3183Revision 6: February 07, 2014 1 of 106 8.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 2 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 Summary ...................................................... 9 1. PLANNING INFORMATION ........................................ 1 3 A. Effectivity ............................................... 1 3 1. Airplanes ............................................ 1 3 2. Spares Affected ........................................ 1 7 B. Concurrent Requirements ...................................... 1 7 C. Reason ................................................ 1 7 D. Description .............................................. 1 8 E. Compliance .............................................. 2 0 F. Approval ............................................... 3 3 G. Manpower .............................................. 3 4 H. Weight and Balance Changes .................................... 3 6 I. Electrical Load Data ......................................... 3 6 J. References .............................................. 3 6 1. Existing Data: ......................................... 3 6 2. Data Supplied with this Service Bulletin: ........................... 3 7 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 7 K. Publications Affected ........................................ 3 7 L. Interchangeability and Intermixability of Parts ........................... 3 8 M. Software Accomplishment Summary ................................ 3 8 2. MATERIAL INFORMATION ........................................ 3 9 A. Material - Price and Availability ................................... 3 9 B. Industry Support Information .................................... 3 9 C. Parts Necessary for Each Airplane ................................. 3 9 1. Kits/Parts ............................................ 3 9 2. Parts and Materials Supplied by the Operator ........................ 4 5 3. Parts Modified and Reidentified ................................ 4 6 4. Parts Removed and Not Replaced .............................. 4 6 D. Parts Necessary to Change Spares ................................. 4 6 E. Special Tooling - Price and Availability ............................... 4 7 F. Special Tooling Necessary to do this Service Bulletin ....................... 4 7 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 4 9 A. GENERAL INFORMATION ..................................... 4 9 B. WORK INSTRUCTIONS ....................................... 5 0 FIGURE 1: THIS FIGURE IS DELETED .................................. 6 2 FIGURE 2: THIS FIGURE IS DELETED .................................. 6 3 FIGURE 3: NACELLE STRUT # 2 AND # 3 MIDSPAR FITTING INSPECTION - LIFE LIMIT PROGRAM .................................................. 6 4 FIGURE 4: NACELLE STRUT # 2 AND # 3 TORQUE BULKHEAD AND MIDSPAR CHORD INSPECTIONS .................................................. 6 7 FIGURE 5: NACELLE STRUT # 2 AND # 3 DRAG FITTING AND FRONT SPAR SUPPORT INSPECTIONS .................................................. 7 0 FIGURE 6: NACELLE STRUT # 1 AND # 4 MIDSPAR FITTING INSPECTION - LIFE LIMIT PROGRAM .................................................. 7 5 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 3 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 4 FIGURE 7: NACELLE STRUT # 1 AND # 4 TORQUE BULKHEAD AND MIDSPAR CHORD INSPECTIONS .................................................. 7 8 FIGURE 8: NACELLE STRUT # 1 AND # 4 DRAG FITTING AND FRONT SPAR SUPPORT INSPECTIONS .................................................. 8 1 FIGURE 9: NACELLE STRUT # 2 AND # 3 MIDSPAR FITTING INSPECTION - LIFE-LIMIT PROGRAM - MID INTERVAL INSPECTION ................................ 8 6 FIGURE 10: NACELLE STRUT # 1 AND # 4 MIDSPAR FITTING INSPECTION - LIFE-LIMIT PROGRAM - MID INTERVAL INSPECTION ................................ 8 9 FIGURE 11: NACELLE STRUT # 1, # 2, # 3 AND # 4 INBOARD SIDE OVERWING SUPPORT FITTING INSPECTION ......................................... 9 2 FIGURE 12: NACELLE STRUT # 1, # 2, # 3 AND # 4 OUTBOARD SIDE OVERWING SUPPORT FITTING INSPECTION ......................................... 9 4 FIGURE 13: NACELLE STRUT # 1, # 2, # 3 AND # 4 OUTBOARD SIDE OVERWING FASTENER INSTALLATION ........................................ 9 6 APPENDIX A: EXISTING PARTS ACCOUNTABILITY ............................ 9 8 APPENDIX B: NACELLE STRUT # 1 AND # 4 - DRAG FITTING - CHAMFER / RADIUS INSPECTION . 101 APPENDIX C: BUSHING DIMENSIONS FOR DRAG FITTING ATTACHMENT HOLES ......... 1 0 3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 4 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 5 Commercial Airplanes 707 Service Bulletin ALERT Revision Transmittal SheetNumber: A3183Original Issue: June 27, 1975 Revision 6: February 07, 2014 ATA System: 5410 SUBJECT: NACELLE - Inboard and Outboard Nacelle Strut - Midspar Fitting - Inspection and Replacement This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION More work is necessary on the airplane(s) changed in accordance with Revision 5 of this service bulletin. Install new inboard and outboard midspar fittings to each nacelle strut in accordance with the midspar fitting life-limit program. Also, do detailed inspection and High Frequency Eddy Current (HFEC) inspection of the nacelle strut midspar fittings in accordance with midspar fitting life-limit program mid interval inspection. Federal Aviation Administration (FAA) Airworthiness Directive AD 93-11-02 is related to this service bulletin. Federal Aviation Administration (FAA) Airworthiness Directive AD 2012-16-12 is related to this service bulletin. 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. Airplane line numbers 0910-0912, 0914-0915, 0917-0919, 0922-0923, 0925-0925, 0928-0929, 0936-0936, 0938-0938, 0941-0941 were added to Group 1 of this service bulletin effectivity. REASON FOR REVISION This revision is sent to give instructions to install new inboard and outboard midspar fittings to each nacelle strut and to add detailed inspections and High Frequency Eddy Current (HFEC) inspections of each nacelle strut midspar fitting. Instructions for detailed inspections and HFEC inspections of each nacelle strut torque bulkhead, midspar chord, drag fitting and front spar support are added. These sections were changed: 1. Background: Is updated and a new planning table added. 2. Action and Description: Is updated to install new inboard and outboard midspar fittings to each nacelle strut and to add new detailed inspections and High Frequency Eddy Current (HFEC) inspections of the midspar fittings, torque bulkhead, midspar chords, drag fitting and front spar support with the engine and nacelle removed from the airplane. 3. Summary, Effectivity, statement is updated. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 5 of 106 ### Page 6 4. Summary, Compliance: Added/Changed Federal Aviation Administration (FAA) Airworthiness Directive statements. 5. Summary, Industry Support Information: Section is added. 6. Summary, Manpower: Is updated to show a new reference. 7. Paragraph 1.E., Compliance: Added/Changed Federal Aviation Administration (FAA) Airworthiness Directive statements. Added compliance times and tables. 8. Paragraph 1.F., Approval: Is updated and new approval statements are added. 9. Paragraph 1.G., Manpower: New manpower times and tables are added. 10. Paragraph 1.J.1., Existing Data: Reference to Standard Overhaul Practices Manual (SOPM), Boeing Service Related Problem (SRP) and Non-Destructive Testing (NDT) and an Airworthiness Directive are added. 11. Paragraph 1.J.2., Data Supplied With This Service Bulletin: New drawings are added. 12. Paragraph 1.J.3., Installation Drawings Used in the Preparation of this Service Bulletin: New drawings are added. 13. Paragraph 1.K., Publications Affected: A new publication is added. 14. Paragraph 1.M., Software Accomplishment Summary: Section is added. 15. Paragraph 2.A., Material - Price and Availability: Is updated to show price and availability of new top kits. 16. Paragraph 2.C.1., Kits/Parts: Are updated to show two new top kits. 17. Paragraph 3.A., General Information: The notes section is updated. 18. Paragraph 3.B., Work Instructions: Are updated to include installation of new inboard and outboard midspar fittings to each nacelle strut and new detailed inspections and High Frequency Eddy Current (HFEC) inspections of the midspar fittings, torque bulkhead, midspar chords, drag fitting and front spar support with the engine and nacelle removed from the airplane. 19. FIGURE 1 and FIGURE 2: Are deleted. 20. FIGURE 3 and FIGURE 6: Are added to inspect the midspar fittings. 21. FIGURE 4 and FIGURE 7: Are added to inspect the torque bulkhead and midspar chords. 22. FIGURE 5 and FIGURE 8: Are added to inspect the drag fittings and front spar supports. 23. FIGURE 9 and FIGURE 10: Are added to inspect the midspar fittings. 24. FIGURE 11, FIGURE 12 and FIGURE 13: Are added to inspect the inboard and outboard overwing support fitting. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 6 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 7 25. Appendix A: The existing parts accountability data has been moved from the material information section to Appendix A. 26. Appendix B: Is added to show drag fitting chamfer/radius data for nacelle struts # 1 and # 4. 27. Appendix C: Is added to show bushing dimensions for drag fittings attachment holes. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY June 27, 1975Original Issue: May 13, 1977Revision 1: January 28, 1988Revision 2: January 31, 1991Revision 3: July 09, 1992Revision 4: September 16, 1993Revision 5: February 07, 2014Revision 6: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 7 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 8 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 8 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT BLANK PAGE ### Page 9 Commercial Airplanes 707 Service Bulletin ALERT SummaryNumber: A3183Original Issue: June 27, 1975 Revision 6: February 07, 2014 ATA System: 5410 SUBJECT: NACELLE - Inboard and Outboard Nacelle Strut - Midspar Fitting - Inspection and Replacement 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 This service bulletin gives instructions to inspect for any crack and to install a new number (#) 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fitting. If the work given in this service bulletin is not accomplished, a crack in the inboard and outboard midspar fitting may go undetected. An undetected crack could result in the loss of structural integrity of the midspar fitting which could cause an unsafe separation of the engine which may result in a wing fire and/or the loss of the airplane. Operators have reported more than 45 cracked midspar fittings on more than 40 turbofan airplanes with approximately 9,900 to 63,000 flight hours. On five airplanes, fracture of the midspar fittings resulted in separation of the inboard strut and engine from the airplane in flight. In two of those instances, the inboard nacelle strut contacted the outboard engine, causing it to separate from the airplane. Operators have also reported cracking in the transition radius of the # 1 and # 4 engine nacelle strut inboard and outboard midspar fittings. There have been several documented cases of the outboard engine departing the airplane in flight. However, the midspar fittings cannot be clearly shown to be the major cause of the outboard engines departing the airplane. The reported cracks on the # 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fittings were found to be vertical at the lug hole or across the double horizontal tangs at the radius where tangs merge with lug. Analysis indicates the 4330 steel midspar fittings cracked as a result of stress corrosion and/or fatigue at lug and fatigue at tangs. A new life limiting program for the # 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fittings and a redesign of the # 1 and # 4 engine nacelle strut inboard and outboard midspar fittings will prevent an unsafe separation of an engine due to an undetected cracked condition in a midspar fitting. Boeing Service Related Problem (SRP) 707-SRP-54-0105 is related to this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 9 of 106 ### Page 10 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 AffectedYesSpares Affected Paragraph 1.E., ComplianceYesAD Related Paragraph 1.H., Weight and Balance ChangesYesWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedYesPublications Affected Paragraph 1.K., Publications AffectedYesAirplane 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 18114-RS, PRR 17941) Midspar Fitting Life-Limit Program: Remove each engine and nacelle strut from the airplane. Remove the inboard and outboard midspar fittings from each nacelle strut. Do a detailed inspection and a High Frequency Eddy Current (HFEC) inspection of each nacelle strut inboard and outboard midspar fitting for any crack. If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do detailed inspection and HFEC inspection of the overwing support fitting for any crack. If any crack is found in overwing support fitting contact Boeing for repair instructions and do the repair instructed by Boeing or install a new overwing support fitting in accordance with Boeing service bulletin 3173 (707-3173). Do an open hole HFEC inspection of the vacated holes on each torque bulkhead and each midspar chord for any crack. If any crack is found in a torque bulkhead or midspar chord rivet hole, oversize the hole or contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack is found in a torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Do an open hole HFEC inspection of each drag fitting attachment hole for any crack. If any crack is found in a drag fitting attachment hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If no crack is found in a drag fitting attachment hole, install new operator supplied bushings. Do an open hole and a surface HFEC inspection of each front spar support for any crack. If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). Install new inboard and outboard midspar fittings. Midspar Fitting Life-Limit Program Mid Interval Inspection: Remove each engine and nacelle strut from the airplane. Do a detailed inspection and a HFEC inspection of each nacelle strut inboard and outboard midspar fitting for any crack. If any crack is found in the inboard or outboard midspar fitting, remove the torque bulkhead and each inboard and outboard midspar fittings. Do an open hole HFEC inspection of the vacated holes on the torque bulkhead and midspar chord for any crack. If any crack is found in the torque bulkhead or midspar chord rivet hole, oversize the hole or contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack is found in the torque bulkhead or midspar Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 10 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 11 chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do a detailed inspection and an open hole HFEC inspection of the overwing support fitting for any crack. If any crack is found in overwing support fitting contact Boeing for repair instructions and do the repair instructed by Boeing or install a new overwing support fitting in accordance with Boeing service bulletin 3173 (707-3173). Do an open hole HFEC inspection of each drag fitting attachment hole for any crack. If any crack is found in a drag fitting attachment hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If no crack is found in a drag fitting attachment hole, install new operator supplied bushings. Do an open hole and a surface HFEC inspection of each front spar support for any crack. If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). If any crack is found in the inboard or outboard midspar fitting, replace the midspar fitting. EFFECTIVITY All 707-100 LONG BODY, -100B LONG BODY, -100B SHORT BODY, -200, -300, -300B, -300C, -400, and 720, 720B Airplane(s). Refer to Paragraph 1.A., Effectivity, for the list of affected airplanes. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 93-11-02 is related to this service bulletin. Federal Aviation Administration (FAA) Airworthiness Directive AD 2012-16-12 is related to this service bulletin. 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 not available for the inspection, and/or repair procedures given in this service bulletin. MANPOWER Refer to Paragraph 1.G., Manpower. MATERIAL INFORMATION Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 11 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 12 (OCR) BOEING SERVICE BULLETIN A3183 ALERT ALERT NACELLE STRUT #4 NACELLE STRUT #3 NACELLE STRUT #2 NACELLE STRUT #1 MIDSPAR FITTING CRACKS UPPER HORIZONTAL TANG VERTICAL TANG NACELLE STRUT FWD ' LOWER HORIZONTAL TANG (TYPICAL) INSTALL NEW MIDSPAR FITTING IN ACCORDANCE WITH MIDSPAR FITTING LIFE-LIMIT PROGRAM. DO INSPECTIONS OF THE MIDSPAR FITTINGS FOR ANY CRACK IN ACCORDANCE WITH MIDSPAR FITTING LIFE-LIMIT PROGRAM MID INTERVAL INSPECTION. Original Issue: June 27, 1975 Revision 6: February 07, 2014 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING A3183 Work - See page 1 for details. 12 of 106 ### Page 13 Commercial Airplanes 707 Service Bulletin ALERT Number: A3183 Original Issue: June 27, 1975 Revision 6: February 07, 2014 ATA System: 5410 SUBJECT: NACELLE - Inboard and Outboard Nacelle Strut - Midspar Fitting - Inspection and Replacement 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 airplane(s) shown below. Refer to Service Bulletin Index D6-1647 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. DESCRIPTIONCONFIGURATIONGROUP All 707-100 LONG BODY, -100B LONG BODY, -100B SHORT BODY, 707-200, 707-300, 707-300B, 707-300C, 707-400, 720, 720B Airplanes -1 Airplane Models: 707-100 LONG BODY, 707-100B LONG BODY, 707-100B SHORT BODY, 707-200, 707-300, 707-300B, 707-300C, 707-400, 720, 720B GroupVariable Number 1B0001 - B0029 1B0101 - B0125 1B0201 - B0203 1B0301 - B0306 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 13 of 106 ### Page 14 GroupVariable Number 1B0401 - B0402 1B0501 - B0515 1B2001 - B2008 1B2091 - B2092 1B2101 - B2116 1B2191 - B2194 1B2199 1B2201 - B2227 1B2401 - B2403 1B2501 - B2502 1B2551 - B2553 1B2601 - B2608 100001 - 00002 100004 - 00006 100101 100103 - 00113 100115 - 00153 100201 - 00205 100301 - 00305 100401 - 00449 100471 - 00475 100501 - 00513 100601 100701 - 00703 102001 - 02020 102101 - 02121 102201 - 02207 102301 - 02303 102401 - 02418 104001 - 04005 104020 - 04022 104101 - 04106 104201 - 04218 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 14 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 15 GroupVariable Number 104271 - 04272 104301 - 04303 105001 - 05060 105101 - 05138 105201 - 05208 105301 - 05312 105401 105601 - 05605 105631 - 05635 105701 - 05703 105801 - 05802 105821 - 05827 105831 - 05833 105851 - 05854 105891 - 05892 105921 - 05923 105941 - 05942 105961 - 05970 106001 - 06002 106101 106401 - 06404 106451 106461 107001 - 07017 107041 - 07059 107071 - 07081 107101 - 07109 107181 107191 107201 - 07215 107251 - 07271 107401 - 07407 107451 - 07458 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 15 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 16 GroupVariable Number 107501 - 07504 107601 - 07626 107661 - 07662 107681 - 07684 107701 - 07702 107801 - 07821 107901 - 07907 108001 - 08008 108021 108051 - 08056 108071 - 08077 108101 - 08104 108121 - 08129 108141 - 08144 108151 - 08153 108171 - 08173 108191 - 08192 108201 - 08210 108221 - 08224 108241 - 08244 108251 108261 108271 108301 - 08320 108324 - 08330 108333 108401 - 08410 108451 - 08452 108471 - 08475 108501 - 08502 108551 - 08553 108581 - 08582 109001 - 09006 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 16 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 17 GroupVariable Number 109101 - 09107 109161 - 09167 109201 - 09204 109221 - 09223 109227 109231 - 09232 109251 109271 109281 109286 - 09290 109411 109421 109438 109441 2. Spares Affected Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for the recommended use. B. Concurrent Requirements None. C. Reason This service bulletin gives instructions to inspect for any crack and to install a new number (#) 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fitting. If the work given in this service bulletin is not accomplished, a crack in the inboard and outboard midspar fitting may go undetected. An undetected crack could result in the loss of structural integrity of the midspar fitting which could cause an unsafe separation of the engine which may result in a wing fire and/or the loss of the airplane. Operators have reported more than 45 cracked midspar fittings on more than 40 turbofan airplanes with approximately 9,900 to 63,000 flight hours. On five airplanes, fracture of the midspar fittings resulted in separation of the inboard strut and engine from the airplane in flight. In two of those instances, the inboard nacelle strut contacted the outboard engine, causing it to separate from the airplane. Operators have also reported cracking in the transition radius of the # 1 and # 4 engine nacelle strut inboard and outboard midspar fittings. There have been several documented cases of the outboard engine departing the airplane in flight. However, the midspar fittings cannot be clearly shown to be the major cause of the outboard engines departing the airplane. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 17 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 18 The reported cracks on the # 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fittings were found to be vertical at the lug hole or across the double horizontal tangs at the radius where tangs merge with lug. Analysis indicates the 4330 steel midspar fittings cracked as a result of stress corrosion and/or fatigue at lug and fatigue at tangs. A new life limiting program for the # 1, # 2, # 3 and # 4 engine nacelle strut inboard and outboard midspar fittings and a redesign of the # 1 and # 4 engine nacelle strut inboard and outboard midspar fittings will prevent an unsafe separation of an engine due to an undetected cracked condition in a midspar fitting. Revision 1 was issued to provide improved access for inspection at the root of the upper tang of the fitting where primary cracking occurs. Revision 2 was issued to modify inspection requirements so that repeat inspections on affected airplanes were accomplished at 1500 flight hours, 600 flight cycles, or 750 flight cycles, depending on model, whichever comes first. The 1.30 inch material removal dimension in Detail I and II of Figure 1 was changed to 1.50 inch to allow improved space for cleaning. Also, Notice of Status Change, dated November 30, 1979, was incorporated that added Boeing service Bulletin 3377, "Engine Nacelle Droop Strip Installation" to prior or concurrent incorporation recommendation. Revision 3 was issued to tell operators of the 707/720 Structures Working Group recommendations. Revision 4 was issued as a partial revision by telegraph to tell operators that the Accomplishment Instructions and Circle Notes 5, 8, and 9 in Figure 1, Inspection, were revised. It included the removal of the sailboat fairing, more cleaning, and new improved Borescope inspection instructions. Revision 5 is issued as a follow-up of partial release telegraphic Revision 4. New information about availability of replacement fittings is given. Figure 1 and 2 titles are changed to more accurately describe their contents. The illustrations in the Summary Page and in Figures 1 and 2 are revised to show locators. A new View A-A in Figure 1 is added to show a new lug area for inspection. Man hour requirements for Borescope inspection are included. Reference to new Airworthiness Directive (AD) 93-11-02, Amendment 39-8594, dated June 4, 1993, is included. Operators are referred to this AD for compliance thresholds for this bulletin. Therefore, the flight hour and flight cycle data for inspection thresholds in Notice of Status Change SB 3183 NSC 2 is not included in this revision. Revision 6 is sent to give instructions to install new inboard and outboard midspar fittings to each nacelle strut and to add detailed inspections and High Frequency Eddy Current (HFEC) inspections of each nacelle strut midspar fitting. Instructions for detailed inspections and HFEC inspections of each nacelle strut torque bulkhead, midspar chord, drag fitting and front spar support are added. Boeing Service Related Problem (SRP) 707-SRP-54-0105 is related to this service bulletin. D. Description Midspar Fitting Life-Limit Program: Remove each engine and nacelle strut from the airplane. Remove the inboard and outboard midspar fittings from each nacelle strut. Do a detailed inspection and a High Frequency Eddy Current (HFEC) inspection of each nacelle strut inboard and outboard midspar fitting for any crack. If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do detailed inspection and HFEC inspection of the overwing support fitting for any crack. If any crack is found in overwing support Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 18 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 19 fitting contact Boeing for repair instructions and do the repair instructed by Boeing or install a new overwing support fitting in accordance with Boeing service bulletin 3173 (707-3173). Do an open hole HFEC inspection of the vacated holes on each torque bulkhead and each midspar chord for any crack. If any crack is found in a torque bulkhead or midspar chord rivet hole, oversize the hole or contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack is found in a torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Do an open hole HFEC inspection of each drag fitting attachment hole for any crack. If any crack is found in a drag fitting attachment hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If no crack is found in a drag fitting attachment hole, install new operator supplied bushings. Do an open hole and a surface HFEC inspection of each front spar support for any crack. If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). Install new inboard and outboard midspar fittings. Midspar Fitting Life-Limit Program Mid Interval Inspection: Remove each engine and nacelle strut from the airplane. Do a detailed inspection and a HFEC inspection of each nacelle strut inboard and outboard midspar fitting for any crack. If any crack is found in the inboard or outboard midspar fitting, remove the torque bulkhead and each inboard and outboard midspar fittings. Do an open hole HFEC inspection of the vacated holes on the torque bulkhead and midspar chord for any crack. If any crack is found in the torque bulkhead or midspar chord rivet hole, oversize the hole or contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack is found in the torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do a detailed inspection and an open hole HFEC inspection of the overwing support fitting for any crack. If any crack is found in overwing support fitting contact Boeing for repair instructions and do the repair instructed by Boeing or install a new overwing support fitting in accordance with Boeing service bulletin 3173 (707-3173). Do an open hole HFEC inspection of each drag fitting attachment hole for any crack. If any crack is found in a drag fitting attachment hole, contact Boeing for repair instructions and do the repair instructed by Boeing. If no crack is found in a drag fitting attachment hole, install new operator supplied bushings. Do an open hole and a surface HFEC inspection of each front spar support for any crack. If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). If any crack is found in the inboard or outboard midspar fitting, replace the midspar fitting. NOTE: Prior or concurrent incorporation of Boeing service bulletin 3377 (707-3377), "Engine Nacelle Droop Strip Installation", is recommended. Revision 6 - More work is necessary on the airplane(s) changed in accordance with Revision 5 of this service bulletin. Install new inboard and outboard midspar fittings to each nacelle strut in accordance with the midspar fitting life-limit program. Also, do detailed inspection and High Frequency Eddy Current (HFEC) inspection of the nacelle strut midspar fittings in accordance with midspar fitting life-limit program mid interval inspection. The work in this service bulletin is done in the maintenance zone(s) given below. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 19 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 20 Affected Maintenance Zones ZoneModel 4-55, 4-56, 4-57, 4-58707-100 LONG BODY, 707- 100B LONG BODY, 707-100B SHORT BODY, 707-200, 707- 300, 707-300B, 707-300C, 707- 400, 720, 720B E. Compliance Federal Aviation Administration (FAA) Airworthiness Directive AD 93-11-02 is related to this service bulletin. Federal Aviation Administration (FAA) Airworthiness Directive AD 2012-16-12 is related to this service bulletin. 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. NOTE: Table 1 is not intended to be mandated by the FAA. The actions in Table 1 do not satisfy the requirements of Table 2, 3, 4 and 5. Table 1: Engine Number (#) 1, 2, 3 and 4 Nacelle Strut Inspection Repeat Interval (Not to Exceed) Compliance TimeActionCondition Before every flight.Before every flight.Action 1.1: Do a side force inspection of the engine # 1, # 2, # 3 and # 4 to inspect for any un- usual structural noises in accordance with Para- graph 3.B., Work Instruc- tions Part 1.a. All airplanes. (a) Action 1.2: Do a general visual inspection of en- gine # 1, # 2, # 3 and # 4 nacelle strut for signs of droop or flexure damage in accordance with Para- graph 3.B., Work Instruc- tions Part 1.b. (a) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 20 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 21 Table 1: Engine Number (#) 1, 2, 3 and 4 Nacelle Strut Inspection Repeat Interval (Not to Exceed) Compliance TimeActionCondition Before further flight. Before further flight. Do the Life-Limit Pro- gram-Mid Interval Inspec- tions in accordance with Paragraph 3.B., Work In- structions Part 4 or Part 5. If any signs of droop or flexure damage or any un- usual structural noises or broken midspar fitting are found during the inspec- tions accomplished in ac- cordance with Action 1.1 or Action 1.2. (a) It is Boeing's intention, that this action does not have to be accomplished by a qualified mechanic. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 21 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 22 Table 2: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition 3,000 flight cycles or 96 months, whichever occurs first. (a) Within 18 months af- ter the Revi- sion 6 date of this ser- vice bul- letin. Within 600 flight cycles after the Revision 6 date of this service bul- letin. Remove the inboard and out- board midspar fittings in accor- dance with Paragraph 3.B., Work Instructions, Part 2.d. All airplanes. Action 2.1: Do a detailed inspec- tion and a surface High Frequen- cy Eddy Current (HFEC) inspec- tion of the inboard and outboard midspar fittings for any crack in accordance with Paragraph 3.B., Work Instructions, Part 2.e. Action 2.2: Do an open hole HFEC inspections of the torque bulkhead, midspar chord, drag fitting and front spar support for any crack in accordance with Paragraph 3.B., Work Instruc- tions, Part 2.f., Part 2.g. & Part 2.i. Action 2.3: Do a surface HFEC inspection of the front spar sup- port for any crack in accordance with Paragraph 3.B., Work In- structions, Part 2.j. -Before further flight.Action 2.4: Do an open hole HFEC inspection for any crack in the two forward most fastener holes common to the inboard side of the nacelle strut over- wing support fitting and the wing front spar upper chord in accor- dance with Paragraph 3.B., Work Instructions, Part 6. Any crack equal to or larger than 0.3 inch found during the inspections accomplished in accordance with Action 2.1. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(1). No crack is found during the in- spections accomplished in ac- cordance with Action 2.4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 22 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 23 Table 2: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Action 2.5: Do an open hole HFEC inspection of the two for- ward most fastener holes com- mon to the outboard side of the nacelle strut overwing support fitting and the wing front spar upper chord for any crack in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2). Any crack found during the in- spections accomplished in ac- cordance with Action 2.4. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2)(a). No crack is found during the in- spections accomplished in ac- cordance with Action 2.5. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 6.a.(3). Any crack found during the in- spections accomplished in ac- cordance with Action 2.4 or Ac- tion 2.5. Or Install a new nacelle strut over- wing support fitting in accor- dance with Paragraph 3.B., Work Instructions, Part 6.a.(3) and Boeing service bulletin 3173 (707-3173). -Before further flight.Action 2.6: Oversize holes and do an open hole HFEC inspec- tion in accordance with Para- graph 3.B., Work Instructions, Part 2.f.(1). Any crack is found in a vacated torque bulkhead and midspar chord rivet hole during the in- spections accomplished in ac- cordance with Action 2.2. -Before further flight.Oversize the crack free rivet holes and install new midspar fittings in accordance with Paragraph 3.B., Work Instruc- tions, Part 2.f.(1)(a). If the crack is removed by oversizing procedure accom- plished in accordance with Ac- tion 2.6. -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 2.f.(1)(b). If the crack is not removed dur- ing the oversizing procedure accomplished in accordance with Action 2.6. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 23 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 24 Table 2: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 2.f.(2). Any crack is found in a vacated torque bulkhead and midspar chord bolt hole during the in- spections accomplished in ac- cordance with Action 2.2. -Before further flight.Install new inboard and out- board midspar fittings and the existing torque bulkhead in ac- cordance with Paragraph 3.B., Work Instructions, Part 2.f.(3). No crack is found in the midspar chords or the torque bulkhead during the inspections accomplished in accordance with Action 2.2. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 2.g.(1). Any crack found in a drag fitting attachment hole during the in- spections accomplished in ac- cordance with Action 2.2. -Before further flight.Install new bushings in accor- dance with Paragraph 3.B., Work Instructions, Part 2.g.(2). No crack found in the drag fit- ting attachment holes during the inspections accomplished in accordance with Action 2.2. -Before further flight.Install a new front spar support in accordance with Paragraph 3.B., Work Instructions, Part 2.i.(1); Part 2.j.(1) and Boeing service bulletin 3366 (707- 3366). Any crack found in the front spar support during the inspec- tions accomplished in accor- dance with Action 2.2 or Action 2.3. (a) There is no terminating action for the repeat inspections. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 24 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 25 Table 3: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition 3,000 flight cycles or 96 months, whichever occurs first. (a) Within 18 months af- ter the Revi- sion 6 date of this ser- vice bul- letin. Within 600 flight cycles after the Revision 6 date of this service bul- letin. Remove the inboard and out- board midspar fittings in accor- dance with Paragraph 3.B., Work Instructions, Part 3.d. All airplanes. Action 3.1: Do a detailed inspec- tion and a surface High Frequen- cy Eddy Current (HFEC) inspec- tion of the inboard and outboard midspar fittings for any crack in accordance with Paragraph 3.B., Work Instructions, Part 3.e. Action 3.2: Do an open hole HFEC inspections of the torque bulkhead, midspar chord, drag fitting and front spar support for any crack in accordance with Paragraph 3.B., Work Instruc- tions, Part 3.f., Part 3.g. and Part 3.i. Action 3.3: Do a surface HFEC inspection of the front spar sup- port for any crack in accordance with Paragraph 3.B., Work In- structions, Part 3.j. -Before further flight.Action 3.4: Do an open hole HFEC inspection for any crack in the two forward most fastener holes common to the inboard side of the nacelle strut over- wing support fitting and the wing front spar upper chord in accor- dance with Paragraph 3.B., Work Instructions, Part 6. Any crack equal to or larger than 0.3 inch found during the inspections accomplished in accordance with Action 3.1. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(1). No crack is found during the in- spections accomplished in ac- cordance with Action 3.4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 25 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 26 Table 3: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Action 3.5: Do an open hole HFEC inspection of the two for- ward most fastener holes com- mon to the outboard side of the nacelle strut overwing support fitting and the wing front spar upper chord for any crack in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2). Any crack found during the in- spections accomplished in ac- cordance with Action 3.4. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2)(a). No crack is found during the in- spections accomplished in ac- cordance with Action 3.5. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 6.a.(3). Any crack found during the in- spections accomplished in ac- cordance with Action 3.4 or Ac- tion 3.5. Or Install a new nacelle strut over- wing support fitting in accor- dance with Paragraph 3.B., Work Instructions, Part 6.a.(3) and Boeing service bulletin 3173 (707-3173). -Before further flight.Action 3.6: Oversize hole and do an open hole HFEC inspec- tion in accordance with Para- graph 3.B., Work Instructions, Part 3.f.(1). Any crack is found in a vacated torque bulkhead and midspar chord rivet hole during the in- spections accomplished in ac- cordance with Action 3.2. -Before further flight.Oversize the crack free rivet holes and install new midspar fittings in accordance with Paragraph 3.B., Work Instruc- tions, Part 3.f.(1)(a). If the crack is removed by oversizing procedure accom- plished in accordance with Ac- tion 3.6. -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 3.f.(1)(b). If the crack is not removed dur- ing the oversizing procedure accomplished in accordance with Action 3.6. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 26 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 27 Table 3: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 3.f.(2). Any crack is found in a vacated torque bulkhead and midspar chord bolt hole during the in- spections accomplished in ac- cordance with Action 3.2. -Before further flight.Install new inboard and out- board midspar fittings and the existing torque bulkhead in ac- cordance with Paragraph 3.B., Work Instructions, Part 3.f.(3). No crack is found in the midspar chords or the torque bulkhead during the inspections accomplished in accordance with Action 3.2. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 3.g.(1). Any crack found in a drag fitting attachment hole during the in- spections accomplished in ac- cordance with Action 3.2. -Before further flight.Install new bushings in accor- dance with Paragraph 3.B., Work Instructions, Part 3.g.(2). No crack found in the drag fit- ting attachment holes during the inspections accomplished in accordance with Action 3.2. -Before further flight.Install a new front spar support in accordance with Paragraph 3.B., Work Instructions, Part 3.i.(1), Part 3.j.(1) and Boeing service bulletin 3366 (707- 3366). Any crack found in the front spar support during the inspec- tions accomplished in accor- dance with Action 3.2 or Action 3.3. (a) There is no terminating action for the repeat inspections. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 27 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 28 Table 4: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition (a)Within 48 months from the last midspar fit- ting replace- ment. Within 1,500 flight cycles from the last midspar fit- ting replace- ment. Action 4.1: Do a detailed inspec- tion and a surface High Frequen- cy Eddy Current (HFEC) inspec- tion of the inboard and outboard midspar fittings for any crack in accordance with Paragraph 3.B., Work Instructions, Part 4.c. All airplanes. Action 4.2: Do an open hole HFEC inspections of the drag fitting and front spar support for any crack in accordance with Paragraph 3.B., Work Instruc- tions, Part 4.d. and Part 4.f. Action 4.3: Do a surface HFEC inspection of the front spar sup- port for any crack in accordance with Paragraph 3.B., Work In- structions, Part 4.g. -Before further flight.Remove the inboard and out- board midspar fittings in accor- dance with Paragraph 3.B., Work Instructions, Part 4.c.(1)(b). Any crack found during the in- spections accomplished in ac- cordance with Action 4.1. -Before further flight.Action 4.4: Do an open hole HFEC inspection of the fastener holes in the midspar chords and torque bulkhead for any crack in accordance with Paragraph 3.B., Work Instructions, Part 4.c.(1)(c). -Before further flight.Action 4.5: Do an open hole HFEC inspection for any crack in the two forward most fastener holes common to the inboard side of the nacelle strut over- wing support fitting and the wing front spar upper chord in accor- dance with Paragraph 3.B., Work Instructions, Part 6. Any crack equal to or larger than 0.3 inch found during the inspections accomplished in accordance with Action 4.1. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 28 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 29 Table 4: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Action 4.6: Oversize the hole and do an open hole HFEC in- spection in accordance with Paragraph 3.B., Work Instruc- tions, Part 4.c.(1)(c)1). Any crack found in a vacated torque bulkhead and midspar chord rivet hole during the in- spections accomplished in ac- cordance with Action 4.4. -Before further flight.Oversize the crack free rivet holes and install new midspar fittings in accordance with Paragraph 3.B., Work Instruc- tions, Part 4.c.(1)(c)1)a). If the crack is removed by oversizing procedure accom- plished in accordance with Ac- tion 4.6. -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 4.c.(1)(c)1)b). If the crack is not removed dur- ing the oversizing procedure accomplished in accordance with Action 4.6. -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 4.c.(1)(c)2). Any crack found in a torque bulkhead and midspar chord bolt hole accomplished in accor- dance with Action 4.4. -Before further flight.Install the torque bulkhead and new inboard and outboard midspar fittings in accordance with Paragraph 3.B., Work In- structions, Part 4.c.(1)(c)3). No crack is found in the midspar chords or the torque bulkhead accomplished in ac- cordance with Action 4.4. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(1). No crack is found during the in- spections accomplished in ac- cordance with Action 4.5. -Before further flight.Action 4.7: Do an open hole HFEC inspection of the two for- ward most fastener holes com- mon to the outboard side of the nacelle strut overwing support fitting and the wing front spar upper chord for any crack in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2). Any crack found during the in- spections accomplished in ac- cordance with Action 4.5. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 29 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 30 Table 4: Nacelle Strut # 2 and # 3 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2)(a). No crack is found during the in- spections accomplished in ac- cordance with Action 4.7. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 6.a.(3). Any crack found during the in- spections accomplished in ac- cordance with Action 4.5 and Action 4.7. Or Install a new nacelle strut over- wing support fitting in accor- dance with Paragraph 3.B., Work Instructions, Part 6.a.(3) and Boeing service bulletin 3173 (707-3173). -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 4.d.(1). Any crack is found in a drag fit- ting attachment hole during the inspections accomplished in accordance with Action 4.2. -Before further flight.Install new bushings in accor- dance with Paragraph 3.B., Work Instructions, Part 4.d.(2). No crack found in the drag fit- ting attachment holes during the inspections accomplished in accordance with Action 4.2. -Before further flight.Install a new front spar support in accordance with Paragraph 3.B., Work Instructions, Part 4.f.(1), Part 4.g.(1) and Boeing service bulletin 3366 (707- 3366). Any crack is found in the front spar support during the inspec- tions accomplished in accor- dance with Action 4.2 and Ac- tion 4.3. (a) New midspar fittings are installed after accomplishment of the inspections given in Table 2. After installation of the new midspar fittings, the mid interval inspection compliance time becomes applicable once more. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 30 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 31 Table 5: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition (a)Within 48 months from the last midspar fit- ting replace- ment. Within 1,500 flight cycles from the last midspar fit- ting replace- ment. Action 5.1: Do a detailed inspec- tion and a surface High Frequen- cy Eddy Current (HFEC) inspec- tion of the inboard and outboard midspar fittings for any crack in accordance with Paragraph 3.B., Work Instructions, Part 5.c. All airplanes. Action 5.2: Do an open hole HFEC inspections of the drag fitting and front spar support for any crack in accordance with Paragraph 3.B., Work Instruc- tions, Part 5.d. and Part 5.f. Action 5.3: Do a surface HFEC inspection of the front spar sup- port for any crack in accordance with Paragraph 3.B., Work In- structions, Part 5.g. -Before further flight.Remove the inboard and out- board midspar fittings in accor- dance with Paragraph 3.B., Work Instructions, Part 5.c.(1)(b). Any crack found during the in- spections accomplished in ac- cordance with Action 5.1. -Before further flight.Action 5.4: Do an open hole HFEC inspection of the fastener holes in the midspar chords and torque bulkhead for any crack in accordance with Paragraph 3.B., Work Instructions, Part 5.c.(1)(c). -Before fur- ther flight. Action 5.5: Do an open hole HFEC inspection for any crack in the two forward most fastener holes common to the inboard side of the nacelle strut over- wing support fitting and the wing front spar upper chord in accor- dance with Paragraph 3.B., Work Instructions, Part 6. Any crack equal to or larger than 0.3 inch found during the inspections accomplished in accordance with Action 5.1. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 31 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 32 Table 5: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Action 5.6: Oversize the hole and do an open hole HFEC in- spection in accordance with Paragraph 3.B., Work Instruc- tions, Part 5.c.(1)(c)1). Any crack found in a vacated torque bulkhead and midspar chord rivet hole during the in- spections accomplished in ac- cordance with Action 5.4. -Before further flight.Oversize the crack free rivet holes and install new midspar fittings in accordance with Paragraph 3.B., Work Instruc- tions, Part 5.c.(1)(c)1)a). If the crack is removed by oversizing procedure accom- plished in accordance with Ac- tion 5.6. -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 5.c.(1)(c)1)b). If the crack is not removed dur- ing the oversizing procedure accomplished in accordance with Action 5.6 -Before further flight.Contact Boeing for repair instruc- tions and new inboard and out- board midspar fitting installation instructions and do the work in- structed by Boeing in accor- dance with Paragraph 3.B., Work Instructions, Part 5.c.(1)(c)2). Any crack found in a torque bulkhead and midspar chord bolt hole during the inspections accomplished in accordance with Action 5.4. -Before further flight.Install the torque bulkhead and new inboard and outboard midspar fittings in accordance with Paragraph 3.B., Work In- structions, Part 5.c.(1)(c)3). No crack is found in the midspar chords or the torque bulkhead during the inspections accomplished in accordance with Action 5.4. -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(1). No crack is found during the in- spections accomplished in ac- cordance with Action 5.5. -Before further flight.Action 5.7: Do an open hole HFEC inspection of the two for- ward most fastener holes com- mon to the outboard side of the nacelle strut overwing support fitting and the wing front spar upper chord for any crack in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2). Any crack found during the in- spections accomplished in ac- cordance with Action 5.5. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 32 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 33 Table 5: Nacelle Strut # 1 and # 4 Midspar Fitting Life-Limit Program Mid Interval Inspection Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs First) ActionCondition -Before further flight.Install oversize fasteners in ac- cordance with Paragraph 3.B., Work Instructions, Part 6.a.(2)(a). No crack is found during the in- spections accomplished in ac- cordance with Action 5.7. -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 6.a.(3). Any crack found during the in- spections accomplished in ac- cordance with Action 5.5 and Action 5.7. Or Install a new nacelle strut over- wing support fitting in accor- dance with Paragraph 3.B., Work Instructions, Part 6.a.(3) and Boeing service bulletin 3173 (707-3173). -Before further flight.Contact Boeing for repair instruc- tions and do the repair instruct- ed by Boeing in accordance with Paragraph 3.B., Work Instruc- tions, Part 5.d.(1). Any crack is found in a drag fit- ting attachment hole during the inspections accomplished in accordance with Action 5.2. -Before further flight.Install new bushings in accor- dance with Paragraph 3.B., Work Instructions, Part 5.d.(2). No crack found in the drag fit- ting attachment holes during the inspections accomplished in accordance with Action 5.2. -Before further flight.Install a new front spar support in accordance with Paragraph 3.B., Work Instructions, Part 5.f.(1), Part 5.g.(1) and Boeing service bulletin 3366 (707- 3366). Any crack is found in the front spar support during the inspec- tions accomplished in accor- dance with Action 5.2 and Ac- tion 5.3. (a) New midspar fittings are installed after accomplishment of the inspections given in Table 3. After installation of the new midspar fittings, the mid interval inspection compliance time becomes applicable once more. 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 33 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 34 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. This service bulletin has been approved by the Federal Aviation Administration (FAA). In addition, the Manager of the FAA Seattle Aircraft Certification Office approves replacement of the midspar fittings on the inboard nacelle struts in accordance with Service Bulletin A3183, Revision 6 as an AMOC to the replacement of the midspar fittings specified in paragraph (e) of AD 93-11-02. All provisions of AD 93-11-02 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves accomplishment of the mid-interval inspections specified in Table 4 of paragraph 1.E., Compliance, of Service Bulletin A3183, Revision 6, as an AMOC to the next inspection required by paragraph (h) of AD 2012-16-12 provided the mid-interval inspections are accomplished within 1,500 flight cycles or 48 months from the last midspar fitting replacement, whichever occurs first. The repetitive inspections must continue thereafter as specified in paragraph (h) of AD 2012-16-12. All provisions of AD 2012-16-12 that are not specifically referenced in the above statement remain fully applicable and must be complied with accordingly. G. Manpower Approximately 260 man-hours and two persons are necessary to do this inspection and replacement for each airplane. Man hour savings resulting from common access may be gained by concurrent accomplishment of Boeing service bulletin 2313 (707-2313), "Nacelle Strut Forward Drag Support Fitting Replacement and Midspar Bushing Installation", Boeing service bulletin 2958 (707-2958), "Nacelle Strut Spar Chord Modification", and Boeing service bulletin 3173 (707-3173), "Inboard Nacelle Strut Overwing Support Fitting Modification and Replacement" on commonly affected airplanes. The tables below shows an estimate of the task hours necessary to do the inspection and replacement for each midspar fitting. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task 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 inspect the work  Time to cure the materials  Time to make the parts  Time to find the tools. TABLE 1 : ENGINE NUMBER (#)1, # 2, # 3 AND # 4 NACELLE STRUT INSPECTION Elapsed HoursTask HoursNumber of PersonsTask 0.400.401General Visual in- spection 0.400.401Side Force Inspec- tion Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 34 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 35 TABLE 1 : ENGINE NUMBER (#)1, # 2, # 3 AND # 4 NACELLE STRUT INSPECTION Elapsed HoursTask HoursNumber of PersonsTask 0.800.80TOTAL FOR EACH AIRPLANE TABLE 2: NACELLE STRUT #1, # 2, #3 AND # 4 MIDSPAR FITTING LIFE-LIMIT PROGRAM Elapsed HoursTask HoursNumber of PersonsTask 6.0048.008Open Access 4.5018.004Midspar Fitting Re- moval 2.004.002FIGURE 3 10.6021.202FIGURE 4 4.108.202FIGURE 5 2.004.002FIGURE 6 10.6021.202FIGURE 7 4.108.202FIGURE 8 4.5018.004Midspar Fitting Instal- lation 6.0048.008Close Access 2.008.004Test 56.40 (a)206.80 (a)TOTAL FOR EACH AIRPLANE (a) The estimated task hours do not include time to make repairs. TABLE 3: NACELLE STRUT #1, # 2, #3 AND # 4 MIDSPAR FITTING LIFE-LIMIT PROGRAM MID INTERVAL INSPECTION Elapsed HoursTask HoursNumber of PersonsTask 6.0048.008Open Access 10.6021.202FIGURE 4 (a) 4.108.202FIGURE 5 10.6021.202FIGURE 7 (a) 4.108.202FIGURE 8 2.004.002FIGURE 9 2.004.002FIGURE 10 6.0048.008Close Access 2.008.004Test 26.20 (b)(c)128.40 (b) (c)TOTAL FOR EACH AIRPLANE Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 35 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 36 TABLE 3: NACELLE STRUT #1, # 2, #3 AND # 4 MIDSPAR FITTING LIFE-LIMIT PROGRAM MID INTERVAL INSPECTION Elapsed HoursTask HoursNumber of PersonsTask (a) This task is only required if a crack is found in a midspar fitting. (b) The estimated task hours do not include time for midspar fitting installation or repairs. (c) The estimated task hours do not include time for the inspection of the torque bulkhead and midspar chords of the nacelle strut. TABLE 4: OVERWING SUPPORT FITTING INSPECTION Elapsed HoursTask HoursNumber of PersonsTask 2.202.201FIGURE 11 2.802.801FIGURE 12 2.202.201FIGURE 13 7.207.20TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes Change in Moment (Pound-Inches) Change in Weight (Pounds)Airplane + 836+ 1.0707 I. Electrical Load Data Not applicable. J. References 1. Existing Data: a. Engineering Change Memo PRR 18114-RS, PRR 17941 b. 707 Maintenance Manual Subjects 12-3-1, 71-5-0, 54-01-0 c. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-43-03, 20-50-03, 20-50-10, 20-50-19 d. Boeing service bulletin 2313 (707-2313), "Nacelle Strut Forward Drag Support Fitting Replacement and Bushing Installation" e. Boeing service bulletin 2958 (707-2958), "Nacelle Strut Spar Chord Modification" f. Boeing service bulletin 3173 (707-3173), "Inboard Nacelle Strut Overwing Support Fitting Modification and Replacement" Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 36 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 37 g. Boeing service bulletin 3377 (707-3377), "Engine Nacelle Droop Strip Installation" h. Boeing service bulletin 3366 (707-3366), "Nacelle Support Fitting Inspection, Modification and Replacement" i. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2012-16-12, 93-11-02 j. Boeing Service Related Problem (SRP) 707-SRP-54-0105 k. Service Bulletin Index D6-1647 l. 707, 720 Non-Destructive Testing (NDT) Manual Part 6, 51-00-00, Figure 4, Figure 13, Figure 16, Figure 23, Figure 24, Part 6, 57-40-07, Figure 2 m. 707-100/200 Structural Repair Manual (SRM) 51-2-5 n. 707-300/400 Structural Repair Manual (SRM) 51-2-5 2. Data Supplied with this Service Bulletin: a. Drawings: ADCNDCN/REVSheetTitleDrawing No --1Retrofit Kit, Midspar Fitting Replacement Instl, Outboard Nacelle Strut 65C13839 --1Top Kit - Midspar Fitting Replacement65C13873 --2 --1Kit - Clevis trim Drag Support, Inboard Na- celle 65C14192 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number INBOARD STRUT - NACELLE, ASSEMBLY OF65-2516 OUTBOARD STRUT NAC ASSY OF STRUCTURE65-2494 MIDSPAR INSTALLATION - OUTBOARD NACELLE STRUT64-1062 MIDSPAR INSTALLATION - INBOARD NACELLE STRUT64-1065 The table above lists applicable drawings used to prepare this service bulletin. The drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. The drawings may not be applicable to all airplane configurations or operators. K. Publications Affected Chapter-SectionPublication 54-01, 57-03707 Illustrated Parts Catalog Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 37 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 38 Chapter-SectionPublication 03-20707 Operations Manual 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: June 27, 1975 A3183Revision 6: February 07, 2014 38 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 39 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 as of the Revision 02 date of this Ser- vice Bulletin (US Dollars) ROLT as of the Revision 02 date of this Service Bulletin (Calendar Days) NameKit Number $7,737.00518TOP KIT, MIDSPAR FITTING REPLACEMENT IN- STL - INBOARD NACELLE STRUT 65C13873-1 $7,867.00518TOP KIT, MIDSPAR FITTING REPLACEMENT IN- STL - INBOARD NACELLE STRUT 65C13873-2 $7,800.00518TOP KIT, MIDSPAR FITTING REPLACEMENT IN- STL - INBOARD NACELLE STRUT 65C13873-3 (a)245RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT 65C13839-1 (a)245RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT 65C13839-2 (a) No price available. Contact Boeing for unit price. NOTE: (10) each Midspar Fittings 65-2536-25 and -26 are available July 8, 1993, as end-item parts. B. Industry Support Information Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. 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 . Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 39 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 40 NOTE: Four strut kits and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator , are necessary for each airplane. 65C13873 - KIT, INBOARD NACELLE STRUT MIDSPAR FITTING REPLACEMENT NamePart Number TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-1 (a) TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-2 (b) TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-3 (c) RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT65C13839-1 (d) RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT65C13839-2 (e) (a) Necessary to modify each inboard strut on affected 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C, and 720B turbofan airplanes. (b) Necessary to modify each inboard strut on affected 707-200 and -300 turbojet airplanes. (c) Necessary to modify each inboard strut on affected 707-100 LONG BODY, -400, and 720 turbojet airplanes. (d) Necessary to modify each outboard strut on affected 707-100B LONG BODY, -100B SHORT BODY, - 300B, -300C, and 720B turbofan airplanes. (e) Necessary to modify each outboard strut on affected 707-200 and -300 turbojet airplanes. Kit 65C13873 NotesNameQTYNew Part Number -3-2-1 -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT ..-65C13873-1 -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT .-.65C13873-2 -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT -..65C13873-3 -SUPPORT ANGLE.1165C13873-4 -SUPPORT ANGLE1..65C13873-5 -SHIM.2265C13873-6 -SUPPORT ANGLE11165C13873-7 -SHIM22264-1065-15 -SHIM22264-1065-16 -SHIM22264-1065-17 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 40 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 41 Kit 65C13873 NotesNameQTYNew Part Number -3-2-1 -LT MID SPAR FITTING ASSY11165-2536-15 -RT MID SPAR FITTING ASSY11165-2536-16 -LT MID SPAR FITTING ASSY11165-2536-25 -RT MID SPAR FITTING ASSY11165-2536-26 -FILLER2..65-2747-805 -KIT - CLEVIS TRIM - DRAG SUPPORT - INBOARD NACELLE 11165C14192 -LUG SHIM44466-1044-6 -LUG SHIM22266-1044-7 -LUG SHIM22266-1044-8 -LUG SHIM22266-1044-9 -LUG SHIM22266-1044-10 -LUG SHIM22266-1044-11 -FILLER2..66-1971-1 -FILLER2..66-1971-3 (a)SHEAR HI-LOCK4..BACB30FP8A-4 (a)SHEAR HI-LOCK.44BACB30FP8A-5 (a)SHEAR HI-LOCK622BACB30FP8A-7 (a)SHEAR HI-LOCK4616BACB30FP8A-8 (a)SHEAR HI-LOCK.48BACB30FP8A-9 (a)SHEAR HI-LOCK..2BACB30FP8A-10 (a)SHEAR HI-LOCK..2BACB30FP8A-11 (a)SHEAR HI-LOCK2..BACB30KK8A-4 (a)SHEAR HI-LOCK.22BACB30KK8A-5 (a)SHEAR HI-LOCK311BACB30KK8A-7 (a)SHEAR HI-LOCK238BACB30KK8A-8 (a)SHEAR HI-LOCK.24BACB30KK8A-9 (a)SHEAR HI-LOCK..1BACB30KK8A-10 (a)SHEAR HI-LOCK..1BACB30KK8A-11 (a)TENSION HI-LOCK44.BACB30MC12A-13 (a)TENSION HI-LOCK..4BACB30MC12A-16 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 41 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 42 Kit 65C13873 NotesNameQTYNew Part Number -3-2-1 (a)TENSION HI-LOCK44.BACB30MC12A-21 (a)TENSION HI-LOCK44.BACB30MC12A-23 (a)TENSION HI-LOCK44.BACB30MC12A-24 (a)TENSION HI-LOCK444BACB30MC12A-26 (a)TENSION HI-LOCK..4BACB30MC12A-27 (a)TENSION HI-LOCK..4BACB30MC12A-28 (a)TENSION HI-LOCK..4BACB30MC12A-29 (a)TENSION HI-LOCK888BACB30MC12A-31 (a)TENSION HI-LOCK22.BACB30MD12A-13 (a)TENSION HI-LOCK..2BACB30MD12A-16 (a)TENSION HI-LOCK22.BACB30MD12A-21 (a)TENSION HI-LOCK22.BACB30MD12A-23 (a)TENSION HI-LOCK22.BACB30MD12A-24 (a)TENSION HI-LOCK222BACB30MD12A-26 (a)TENSION HI-LOCK..2BACB30MD12A-27 (a)TENSION HI-LOCK..2BACB30MD12A-28 (a)TENSION HI-LOCK..2BACB30MD12A-29 (a)TENSION HI-LOCK444BACB30MD12A-31 -COLLAR141414BACC30AC12 -COLLAR141634BACC30M8 -COLLAR7817BACC30R8 -COLLAR282828BACC30X12 (a)BOLT.2.BACB30NE7-11X (a)BOLT..2BACB30NE7-13X (a)BOLT.4.BACB30NE7-18X (a)BOLT.2.BACB30NE7-11Y (a)BOLT..2BACB30NE7-13Y (a)BOLT.4.BACB30NE7-18Y (a)BOLT2..BACB30MT7T-11X (a)BOLT4..BACB30MT7T-18X (a)BOLT..4BACB30MT7T-22X Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 42 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 43 Kit 65C13873 NotesNameQTYNew Part Number -3-2-1 (a)BOLT2..BACB30MT7T-11Y (a)BOLT4..BACB30MT7T-18Y (a)BOLT..4BACB30MT7T-22Y -NUT666BACN10HR7 -NUTPLATE222BACN10JR3 (a)RIVET444BACR15BA3D4 (a)RIVET71010BACR15ET7D6 (a)RIVET4..BACR15ET7D9 (a)RIVET24244BACR15ET9D9 -WASHER, PLI..4SPS-X-66149-7.5-16.7 -WASHER, CSK666BACW10BP-71AC -WASHER, PLAIN666BACW10BP-71AP (a)SCREW222NAS603-8P (a)SCREW222NAS603-10BP -WASHER, CSK666BACW10BP-72AC -WASHER,CSK666BACW10BP-72AP (a) 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. Kit 65C13839 NotesNameQTYNew Part Number -2-1 -RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT .-65C13839-1 -RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT -.65C13839-2 (a)SHIM2264-1062-7 (a)SHIM2264-1062-8 (a)SHIM2264-1062-9 (a)FITTING ASSY, MID SPAR, OUTBOARD NACELLE STRUT1165-2534-21 (a)FITTING ASSY, MID SPAR, OUTBOARD NACELLE STRUT1165-2534-22 (a)BOLT2.BACB30FP10A10 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 43 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 44 Kit 65C13839 NotesNameQTYNew Part Number -2-1 (a)BOLT O/S44BACB30FP10A11 (a)BOLT.2BACB30FP10A12 (a)BOLT, PROTRUDING HD.2BACB30FP10A13 (a)BOLT.2BACB30FP8A10 (a)BOLT.2BACB30FP8A11 (a)BOLT.2BACB30FP8A12 (a)BOLT.2BACB30FP8A13 (a)BOLT, PROTRUDING HD.2BACB30FP8A15 (a)BOLT.2BACB30FP8A16 (a)BOLT44BACB30FP8A5 (a)BOLT22BACB30FP8A6 (a)BOLT614BACB30FP8A7 (a)BOLT44BACB30FP8A8 (a)BOLT.4BACB30FP8A9 (a)BOLT4.BACB30MC12A15 (a)BOLT, PROTRUDING HD.4BACB30MC12A16 (a)BOLT4.BACB30MC12A19 (a)BOLT, PROTRUDING HD4.BACB30MC12A22 (a)BOLT4.BACB30MC12A23 (a)BOLT, HEX DRIVE.4BACB30MC12A24 (a)BOLT.4BACB30MC12A25 (a)O/S BOLT.4BACB30MC12A26 (a)BOLT44BACB30MC12A29 (a)BOLT, HEX DRIVE44BACB30MC12A30 (a)BOLT16.BACB30MC6A6 (a)BOLT, 12 PT HEAD2.BACB30US7K13X (a)BOLT, 12 PT HEAD.2BACB30US7K15X (a)BOLT, 12 PT HEAD4.BACB30US7K18X (a)BOLT, 12 PT HEAD.4BACB30US7K20X -COLLAR2424BACC30BH12 -COLLAR68BACC30M10 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 44 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 45 Kit 65C13839 NotesNameQTYNew Part Number -2-1 -COLLAR16.BACC30M6 -COLLAR1634BACC30M8 -NUT66BACN10HR7CD (b)RIVET, UNIVERSAL HD3723BACR15BB7D6C -WASHER, PLAIN66BACW10BP71AC -WASHER, PLAIN66BACW10BP71AP (a) Discard the existing part. (b) 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. 2. Parts and Materials Supplied by the Operator NOTE: Refer to 707 Structural Repair Manual Chapter 51 for alternative fasteners. NotesNameQTYPart Number / Specification -Cadmium PlateAs RequiredAMS-QQ-P-416, Type 1, Class 2 -Chemical Conversion CoatingAs RequiredType 2, Class A -Corrosion Inhibiting CompoundAs RequiredBMS 3-23 or BMS 3-35 -SealantAs RequiredBMS 5-95, Class B2 -PrimerAs RequiredBMS 10-11, Type I -Cleaning SolventAs RequiredBMS 11-7 (a) (b)BoltAs RequiredBACB30MB12-10 (a) (b)CollarAs RequiredBACC30BH12 (c) (g)Straight Bushing - Non PlatedAs Required69-2860-1 (c) (g)Straight Bushing - Non PlatedAs Required69-2860-2 (d) (g) (h)Straight Bushing - PlatedAs Required69-2860-50 (d) (g) (h)Straight Bushing - PlatedAs Required69-2860-51 (d) (g) (h)Straight Bushing - PlatedAs Required69-2860-59 (e) (g)Straight Bushing - Non PlatedAs Required69-2860-3 (e) (g)Straight Bushing - Non PlatedAs Required69-2860-4 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 45 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 46 NotesNameQTYPart Number / Specification (f) (g) (h)Straight Bushing - PlatedAs Required69-2860-52 (f) (g) (h)Straight Bushing - PlatedAs Required69-2860-53 (f) (g) (h)Flanged Bushing - PlatedAs Required69-42475-5 (f) (g) (h)Flanged Bushing - PlatedAs Required69-42475-6 (d) (g) (h)Flanged Bushing - PlatedAs Required69-42475-9 (d) (g) (h)Flanged Bushing - PlatedAs Required69-42475-10 (d) (g) (h)Flanged Bushing - PlatedAs Required69-42475-15 (f) (g) (h)Flanged Bushing - PlatedAs Required69-42475-18 See 707 Maintenance or Overhaul Manual Chapter 20 for procurement. (a) This part is only required if oversizing in accordance with FIGURE 12 or FIGURE 13 is required. (b) A total of four bolts and collars could be required for each nacelle overwing support fitting. (c) This part is required with Top Kit 65C13873-2 and is necessary to modify drag fitting attachment holes on affected 707-200 and -300 turbojet airplanes. (d) This part is required with Top Kit 65C13873-1 and is necessary to modify drag fitting attachment holes on affected 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C, and 720B turbofan airplanes. (e) This part is required with Top Kit 65C13839-2 and is necessary to modify drag fitting attachment holes on affected 707-200 and -300 turbojet airplanes. (f) This part is required with Top Kit 65C13839-1 and is necessary to modify drag fitting attachment holes on affected 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C, and 720B turbofan airplanes. (g) Refer to APPENDIX C for bushing dimensions for drag fittings attachment holes. (h) This part requires cadmium plating. 3. Parts Modified and Reidentified Refer to APPENDIX A for existing parts accountability. 4. Parts Removed and Not Replaced None. D. Parts Necessary to Change Spares To get the kits shown below, refer to Paragraph 2.A., Material - Price and Availability . See Drawing 65C13873, Sheet 1, for kit components. In addition, the applicable operator furnished materials listed in Paragraph 2.C.2., Parts and Materials Supplied by the Operator , are necessary to supplement each of the following kits: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 46 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 47 65C13873 - KIT, INBOARD NACELLE STRUT MIDSPAR FITTING REPLACEMENT QTYNamePart Number -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-1 (a) -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-2 (b) -TOP KIT, MIDSPAR FITTING REPLACEMENT INSTL - INBOARD NACELLE STRUT65C13873-3 (c) (a) Necessary to modify each affected spare equipped strut assembly 65-2510-3001 through -3110, and each spare strut structure assembly 65-2516-3000, -3026, and -3030. (b) Necessary to modify each affected spare equipped strut assembly 65-2510-1 and -2, and each spare strut structure assembly 65-2516-1 and -3027. (c) Necessary to modify each affected spare equipped strut assembly 50-8227-( ), and each spare strut structure assembly 5-85617-( ). 65C13839 - KIT, OUTBOARD NACELLE STRUT MIDSPAR FITTING REPLACEMENT QTYNamePart Number -RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT 65C13839-1 (a) -RETROFIT KIT, MIDSPAR FITTING REPLACEMENT INSTL, OUTBOARD NACELLE STRUT 65C13839-2 (b) (a) Necessary to modify each affected spare equipped strut assembly 65-2488-3001 through -3128, -501, - 502, and each spare strut structure assembly 65-2494-3000, -3015, -3019, -501. (b) Necessary to modify each affected spare equipped strut assembly 65-2488-1 and -2, and each spare strut structure assembly 65-2494, -1, and -3016. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 47 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 48 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 48 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT BLANK PAGE ### Page 49 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. 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 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 8. 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 49 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 50 9. Boeing Service Letter 707-SL-51-029 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. 10. Refer to Appendix A for nacelle struts # 1, # 2, # 3 and # 4 existing parts accountability data. 11. Refer to Appendix B for nacelle struts # 1 and # 4, drag fitting chamfer/radius data. 12. Refer to Appendix C for bushing dimensions for drag fittings attachment holes. 13. 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. 14. 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. 15. 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. 16. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems. 17. At locations where "Boeing service bulletin XXXX" is shown, the XXXX is the base number for a 707 Boeing service bulletin. Where "(707-XXXX)" is mentioned in the service bulletin, it is the same as Boeing service bulletin XXXX. 18. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-' (dash) part number. Boeing Drawing 005W0900 contains more data. B. WORK INSTRUCTIONS 1. PART 1 - Engine Number (#) 1, # 2, # 3 And # 4 Nacelle Strut Inspection a. Do a side force inspection of the engine # 1, # 2, # 3 and # 4. Apply alternating side forces by hand to each side of engine nose cowl to inspect for any unusual structural noises. NOTE: If a fitting is not completely severed, fore and aft movement between a cracked lug and forward drag fitting clevis or between cracked tang ends may not be apparent during this inspection. However, any unusual structural noises during this inspection can indicate the start of a break. (1) If any broken midspar fitting or any unusual structural noises is found, do the Life-Limit Program - Mid Interval Inspections in accordance with Part 4 or Part 5. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 50 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 51 b. Do a General Visual inspection of the engine # 1, # 2, # 3 and # 4 nacelle strut for signs of droop below normal position. Look at the stripe if present for misalignment. In addition, do a General Visual inspection of the fairing straps, access panels and fairings between strut and wing for Flexure damage (buckles, wrinkles, cracks, elongated holes, loose or broken fasteners, etc). Noticeable nacelle droop or flexure damage may indicate that one or both midspar fittings are broken. (1) If any buckles, wrinkles, cracks, elongated holes, loose or broken fasteners, flexure damage to sheet metal or noticeable nacelle droop are found, do the Life-Limit Program - Mid Interval Inspections in accordance with Part 4 or Part 5. 2. PART 2 - Engine # 2 and # 3 Nacelle Strut - Midspar Fitting - Life-Limit Program. a. Remove the engine # 2 and # 3 from the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. b. Remove the nacelle strut # 2 and # 3 from the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. c. Remove/keep the upper portion of the torque bulkhead. Refer to Boeing drawing number 65C13873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. CAUTION: MAKE SURE THE LUG BORE LOCATIONS OF THE OLD MIDSPAR FITTINGS ARE ACCURATELY MAINTAINED ON THE INSTALLATION OF THE NEW MIDSPAR FITTINGS. IF THE LUG BORE LOCATIONS ARE NOT ACCURATELY MAINTAINED MISALIGNMENT OF THE NACELLE STRUT AND THE WING FORWARD DRAG FITTINGS CAN OCCUR. d. Remove the nacelle strut # 2 and # 3 inboard and outboard midspar fittings. Refer to Boeing drawing number 65CI3873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: New midspar fittings are supplied undrilled. As an option fabricate tooling as necessary to maintain the lug bore locations of the old midspar fittings. e. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of the removed nacelle strut # 2 and nacelle strut # 3 inboard and outboard midspar fittings for any crack in accordance with FIGURE 3. (1) If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do the Part 6 - Overwing Support Fitting - Inspection and accomplish the remaining Part 2 inspections. (2) If every crack found is less than 0.3 inch, or if no crack is found, in the inboard or outboard midspar fitting, continue with the Part 2 inspections. f. Do an open hole High Frequency Eddy Current (HFEC) inspections of the vacated holes on the torque bulkhead and midspar chords of the nacelle strut for any crack in accordance with FIGURE 4. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 51 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 52 (1) If any crack is found in a vacated torque bulkhead or midspar chord rivet hole, oversize the 3/16 inch rivet hole to 0.218 - 0.233 inch diameter and do an open hole High Frequency Eddy Current (HFEC) inspection for any crack in accordance with 707, 720 NDT Manual Part 6, 51-00-00, Figure 16, using a 0.02 notch calibration. (a) If no crack is found in the oversized rivet hole, oversize the crack free rivet hole to 0.263-0.265 inch diameter and install new inboard and outboard midspar fittings and existing torque bulkhead with the applicable BACR15BB8D*C oversize fasteners as necessary and in accordance with Boeing drawing number 65C13873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. (b) If any crack is found in the oversized rivet hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. (2) If any crack is found in a vacated torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. (3) If no crack is found in a vacated torque bulkhead or midspar chord fastener hole, install new inboard and outboard midspar fittings and the existing torque bulkhead in accordance with Boeing drawing number 65C13873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. g. Do an open hole High Frequency Eddy Current (HFEC) inspection of the drag fitting attachment holes for any crack in accordance with FIGURE 5. (1) If any crack is found in a drag fitting attachment hole contact Boeing for repair instructions and do the repair instructed by Boeing. (2) If no crack is found in the drag fitting attachment holes, install new operator supplied bushings in accordance with FIGURE 5. Refer to APPENDIX C for bushing dimensions. h. Make sure the corner radius or chamfer at the forward inside edges of the left and right wing forward drag fitting will clear the larger shoulder radius of the mating surface of the new midspar fitting. If the drag fitting will not clear the larger shoulder radius of the mating surface of the new midspar fitting, chamfer the drag fittings in accordance with drawing 65C14192, Sheet 1. (1) If required, re-identify all trimmed drag fittings to indicate incorporation of this service bulletin. Apply stencil markings (service bulletin number) to a visible area of the drag fitting. Refer to SOPM 20-50-10 as an accepted procedure. Make sure that trimmed fittings are used for all subsequent fitting replacements. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 52 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 53 i. Do an open hole High Frequency Eddy Current (HFEC) inspection of the front spar support attachment holes for any crack in accordance with FIGURE 5. (1) If any crack is found in the front spar support attachment holes, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). j. Do a surface High Frequency Eddy Current (HFEC) inspection of the front spar support for any crack in accordance with FIGURE 5. (1) If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). k. Apply sealant to the midspar area in accordance with drawing 65CI3873, Sheet 1 and Sheet 2, zones1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. l. Apply Corrosion Inhibiting Compound (CIC) BMS 3-23, TYPE II, CLASS 2 to the midspar fitting areas. Refer to SOPM 20-43-03 as an accepted procedure. NOTE: Each operator should evaluate his airplanes environment, the inhibitor used, and the application schedule to ensure adequate corrosion protection. Although Boeing has developed BMS 3-23 as a standard for organic corrosion inhibitors compound and recommends its use, other water displacing corrosion preventive compounds can be satisfactory, based on operator evaluation and experience. m. Install the nacelle strut # 2 and # 3 to the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. NOTE: On installation of nacelle strut to the airplane, make sure to install new lug shims (if and as required) to reduce lug-to-clevis gap below 0.002 inch. n. Install the engine # 2 and # 3 to the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. o. Put the airplane back to a serviceable condition. 3. PART 3 - Engine # 1 and # 4 Nacelle Strut - Midspar Fitting - Life-Limit Program. a. Remove the engine # 1 and # 4 from the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. b. Remove the nacelle strut # 1 and # 4 from the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. c. Remove/keep the torque bulkhead. Refer to Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 53 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 54 CAUTION: MAKE SURE THE LUG BORE LOCATIONS OF THE OLD MIDSPAR FITTINGS ARE ACCURATELY MAINTAINED ON THE INSTALLATION OF THE NEW MIDSPAR FITTINGS. IF THE LUG BORE LOCATIONS ARE NOT ACCURATELY MAINTAINED MISALIGNMENT OF THE NACELLE STRUT AND THE WING FORWARD DRAG FITTINGS CAN OCCUR. d. Remove the nacelle strut # 1 and # 4 inboard and outboard midspar fittings. Refer to Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: New midspar fittings are supplied undrilled. As an option fabricate tooling as necessary to maintain the lug bore locations of the old midspar fittings. e. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of the removed nacelle strut # 1 and nacelle strut # 4 inboard and outboard midspar fittings for any crack in accordance with FIGURE 6. (1) If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do the Part 6 - Overwing Support Fitting - Inspection and accomplish the remaining Part 3 inspections. (2) If every crack found is less than 0.3 inch, or if no crack is found, in the inboard or outboard midspar fitting, continue with the Part 3 inspections. f. Do an open hole High Frequency Eddy Current (HFEC) inspections of the vacated holes on the torque bulkhead and midspar chords of the nacelle strut for any crack in accordance with FIGURE 7. (1) If any crack is found in a vacated torque bulkhead or midspar chord rivet hole, oversize the 3/16 inch rivet hole to 0.218 - 0.233 inch diameter and do an open hole High Frequency Eddy Current (HFEC) inspection for any crack in accordance with 707, 720 NDT Manual Part 6, 51-00-00, Figure 16, using a 0.02 notch calibration. (a) If no crack is found in the oversized rivet hole, oversize the crack free rivet hole to 0.263-0.265 inch diameter and install new inboard and outboard midspar fittings and existing torque bulkhead with the applicable BACR15BB8D*C oversize fasteners as necessary and in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. (b) If any crack is found in the oversized rivet hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. (2) If any crack is found in a vacated torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 54 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 55 (3) If no crack is found in a vacated torque bulkhead or midspar chord fastener hole, install new inboard and outboard midspar fittings and the existing torque bulkhead in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. g. Do an open hole High Frequency Eddy Current (HFEC) inspection of the drag fitting attachment holes for any crack in accordance with FIGURE 8. (1) If any crack is found in a drag fitting attachment hole contact Boeing for repair instructions and do the repair instructed by Boeing. (2) If no crack is found in the drag fitting attachment holes, install new operator supplied bushings in accordance with FIGURE 8. Refer to APPENDIX C for bushing dimensions. h. Make sure the corner radius or chamfer at the forward inside edges of the left and right wing forward drag fitting will clear the larger shoulder radius of the mating surface of the new midspar fitting. If the drag fitting will not clear the larger shoulder radius of the mating surface of the new midspar fitting, chamfer the drag fittings in accordance with APPENDIX B. (1) If required, re-identify all trimmed drag fittings to indicate incorporation of this service bulletin. Apply stencil markings (service bulletin number) to a visible area of the drag fitting. Refer to SOPM 20-50-10 as an accepted procedure. Make sure that trimmed fittings are used for all subsequent fitting replacements. i. Do an open hole High Frequency Eddy Current (HFEC) inspection of the front spar support attachment holes for any crack in accordance with FIGURE 8. (1) If any crack is found in the front spar support attachment holes, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). j. Do a surface High Frequency Eddy Current (HFEC) inspection of the front spar support for any crack in accordance with FIGURE 8. (1) If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). k. Apply sealant to the midspar area in accordance with Boeing drawing number 65C13839 Sheet 1. l. Apply Corrosion Inhibiting Compound (CIC) BMS 3-23, TYPE II, CLASS 2 to the midspar fitting areas. Refer to SOPM 20-43-03 as an accepted procedure. NOTE: Each operator should evaluate his airplanes environment, the inhibitor used, and the application schedule to ensure adequate corrosion protection. Although Boeing has developed BMS 3-23 as a standard for organic corrosion inhibitors compound and recommends its use, other water displacing corrosion preventive compounds can be satisfactory, based on operator evaluation and experience. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 55 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 56 m. Install the nacelle strut # 1 and # 4 to the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. NOTE: On installation of nacelle strut to the airplane, make sure to install new lug shims (if and as required) to reduce lug-to-clevis gap below 0.002 inch. n. Install the engine # 1 and # 4 to the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. o. Put the airplane back to a serviceable condition. 4. PART 4 - Engine # 2 And # 3 Nacelle Strut - Midspar Fitting - Life-Limit Program - Mid Interval Inspection a. Remove the engine # 2 and # 3 from the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. b. Remove the nacelle strut # 2 and # 3 from the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. c. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of nacelle strut # 2 and nacelle strut # 3 inboard and outboard midspar fittings for any crack in accordance with FIGURE 9. (1) If any crack is found in the inboard or outboard midspar fitting, do the steps that follow: (a) Remove/keep the upper portion of the torque bulkhead in accordance with Boeing drawing number 65CI3873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. CAUTION: MAKE SURE THE LUG BORE LOCATIONS OF THE OLD MIDSPAR FITTINGS ARE ACCURATELY MAINTAINED ON THE INSTALLATION OF THE NEW MIDSPAR FITTINGS. IF THE LUG BORE LOCATIONS ARE NOT ACCURATELY MAINTAINED MISALIGNMENT OF THE NACELLE STRUT AND THE WING FORWARD DRAG FITTINGS CAN OCCUR. (b) Remove the inboard and outboard midspar fittings in accordance with Boeing drawing number 65CI3873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: New midspar fittings are supplied undrilled. As an option fabricate tooling as necessary to maintain the lug bore locations of the old midspar fittings. (c) Do an open hole High Frequency Eddy Current (HFEC) inspections of the vacated holes on the torque bulkhead and midspar chords of the nacelle strut for any crack in accordance with FIGURE 4. 1) If any crack is found in a vacated torque bulkhead or midspar chord rivet hole, oversize the 3/16 inch rivet hole to 0.218 - 0.233 inch diameter and do an open hole High Frequency Eddy Current (HFEC) inspection for any crack in accordance with 707, 720 NDT Manual Part 6, 51-00-00, Figure 16, using a 0.02 notch calibration. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 56 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 57 a) If no crack is found in the oversized rivet hole, oversize the crack free rivet hole to 0.263-0.265 inch diameter and install new inboard and outboard midspar fittings and existing torque bulkhead with the applicable BACR15BB8D*C oversize fasteners as necessary and in accordance with Boeing drawing number 65CI3873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. b) If any crack is found in the oversized rivet hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. 2) If any crack is found in a vacated torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. 3) If no crack is found in a vacated torque bulkhead or midspar chord fastener hole, install new inboard and outboard midspar fittings and the existing torque bulkhead in accordance with Boeing drawing number 65CI3873, Sheet 1 and Sheet 2, zones 1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. (2) If any crack equal to or larger than 0.3 inch is found in the inboard or outboard midspar fitting, do the Part 6 - Overwing Support Fitting - Inspection and accomplish the remaining Part 4 inspections. (3) If every crack found is less than 0.3 inch, or if no crack is found, in the inboard or outboard midspar fitting, continue with the Part 4 inspections. d. Do an open hole High Frequency Eddy Current (HFEC) inspection of the drag fitting attachment holes for any crack in accordance with FIGURE 5. (1) If any crack is found in a drag fitting attachment hole contact Boeing for repair instructions and do the repair instructed by Boeing. (2) If no crack is found in the drag fitting attachment holes, install new operator supplied bushings in accordance with FIGURE 5. Refer to APPENDIX C for bushing dimensions. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 57 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 58 e. Make sure the corner radius or chamfer at the forward inside edges of the left and right wing forward drag fitting will clear the larger shoulder radius of the mating surface of the new midspar fitting. If the drag fitting will not clear the larger shoulder radius of the mating surface of the new midspar fitting, chamfer the drag fittings in accordance with drawing 65C14192, Sheet 1. (1) If required, re-identify all trimmed drag fittings to indicate incorporation of this service bulletin. Apply stencil markings (service bulletin number) to a visible area of the drag fitting. Refer to SOPM 20-50-10 as an accepted procedure. Make sure that trimmed fittings are used for all subsequent fitting replacements. f. Do an open hole High Frequency Eddy Current (HFEC) inspection of the front spar support attachment holes for any crack in accordance with FIGURE 5. (1) If any crack is found in the front spar support attachment holes, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). g. Do a surface High Frequency Eddy Current (HFEC) inspection of the front spar support in accordance with FIGURE 5. (1) If any crack is found in the front spar support, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). h. Apply sealant to the midspar area in accordance with drawing 65CI3873, Sheet 1 and Sheet 2, zones1 thru 8 for 707B/C and 720B turbofan airplanes, and Zones 7 thru 13 for 707 and 720 turbojet airplanes. i. Apply Corrosion Inhibiting Compound (CIC) BMS 3-23, TYPE II, CLASS 2 to the midspar fitting areas. Refer to SOPM 20-43-03 as an accepted procedure. NOTE: Each operator should evaluate his airplanes environment, the inhibitor used, and the application schedule to ensure adequate corrosion protection. Although Boeing has developed BMS 3-23 as a standard for organic corrosion inhibitors compound and recommends its use, other water displacing corrosion preventive compounds can be satisfactory, based on operator evaluation and experience. j. Install the nacelle strut # 2 and # 3 to the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. NOTE: On installation of nacelle strut to the airplane, make sure to install new lug shims (if and as required) to reduce lug-to-clevis gap below 0.002 inch. k. Install the engine # 2 and # 3 to the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. l. Put the airplane back to a serviceable condition. 5. PART 5 - Engine # 1 And # 4 Nacelle Strut - Midspar Fitting - Life-Limit Program - Mid Interval Inspection a. Remove the engine # 1 and # 4 from the airplane. Refer to 707 Aircraft Maintenance Manual 71-5-0 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 58 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 59 b. Remove the nacelle strut # 1 and # 4 from the airplane. Refer to 707 Aircraft Maintenance Manual 54-01-0 as an accepted procedure. c. Do a detailed inspection and a surface High Frequency Eddy Current (HFEC) inspection of nacelle strut # 1 and nacelle strut # 4 inboard and outboard midspar fittings for any crack in accordance with FIGURE 10. (1) If any crack is found in the inboard or outboard midspar fitting, do the steps that follow: (a) Remove/keep the torque bulkhead in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. CAUTION: MAKE SURE THE LUG BORE LOCATIONS OF THE OLD MIDSPAR FITTINGS ARE ACCURATELY MAINTAINED ON THE INSTALLATION OF THE NEW MIDSPAR FITTINGS. IF THE LUG BORE LOCATIONS ARE NOT ACCURATELY MAINTAINED MISALIGNMENT OF THE NACELLE STRUT AND THE WING FORWARD DRAG FITTINGS CAN OCCUR. (b) Remove the inboard and outboard midspar fittings in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: New midspar fittings are supplied undrilled. As an option fabricate tooling as necessary to maintain the lug bore locations of the old midspar fittings. (c) Do an open hole High Frequency Eddy Current (HFEC) inspections of the vacated holes on the torque bulkhead and midspar chords of the nacelle strut for any crack in accordance with FIGURE 7. 1) If any crack is found in a vacated torque bulkhead or midspar chord rivet hole, oversize the 3/16 inch rivet hole to 0.218 - 0.233 inch diameter and do an open hole High Frequency Eddy Current (HFEC) inspection for any crack in accordance with 707, 720 NDT Manual Part 6, 51-00-00, Figure 16, using a 0.02 notch calibration. a) If no crack is found in the oversized rivet hole, oversize the crack free rivet hole to 0.263-0.265 inch diameter and install new inboard and outboard midspar fittings and existing torque bulkhead with the applicable BACR15BB8D*C oversize fasteners as necessary and in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 59 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT ### Page 60 b) If any crack is found in the oversized rivet hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. 2) If any crack is found in a vacated torque bulkhead or midspar chord bolt hole, contact Boeing for repair instructions and do the repair instructed by Boeing. Any repair must include replacement of the inboard and outboard midspar fittings with new fittings. 3) If no crack is found in a vacated torque bulkhead or midspar chord fastener hole, install new inboard and outboard midspar fittings and the existing torque bulkhead in accordance with Boeing drawing number 65C13839 Sheet 1, zones 1 thru 17 for 707-100B LONG BODY, -100B SHORT BODY, -300B, -300C and 720B turbofan airplanes, and Zones 20 thru 32 for 707-200 and 300 turbojet airplanes. NOTE: On installation of new midspar fitting use the optional lug bore tooling and match drill with existing fastener holes in the midspar and torque bulkhead installations. Make sure fastener Edge Distance (ED) is not less than 1D + 0.050 inch. (2) If any crack in the inboard or outboard midspar fitting is equal to or larger than 0.3 inch, do the Part 6 - Overwing Support Fitting - Inspection and accomplish the remaining Part 5 inspections. (3) If every crack found is less than 0.3 inch, or if no crack is found, in the inboard or outboard midspar fitting, continue with the Part 5 inspections. d. Do an open hole High Frequency Eddy Current (HFEC) inspection of the drag fitting attachment holes in accordance with FIGURE 8. (1) If any crack is found in a drag fitting attachment hole contact Boeing for repair instructions and do the repair instructed by Boeing. (2) If no crack is found in the drag fitting attachment holes, install new operator supplied bushings in accordance with FIGURE 8. Refer to APPENDIX C for bushing dimensions. e. Make sure the corner radius or chamfer at the forward inside edges of the left and right wing forward drag fitting will clear the larger shoulder radius of the mating surface of the new midspar fitting. If the drag fitting will not clear the larger shoulder radius of the mating surface of the new midspar fitting, chamfer the drag fittings in accordance with APPENDIX B. (1) If required, re-identify all trimmed drag fittings to indicate incorporation of this service bulletin. Apply stencil markings (service bulletin number) to a visible area of the drag fitting. Refer to SOPM 20-50-10 as an accepted procedure. Make sure that trimmed fittings are used for all subsequent fitting replacements. f. Do an open hole High Frequency Eddy Current (HFEC) inspection of the front spar support attachment holes in accordance with FIGURE 8. (1) If any crack is found in the front spar support attachment holes, install a new front spar support in accordance with Boeing service bulletin 3366 (707-3366). Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 27, 1975 A3183Revision 6: February 07, 2014 60 of 106 BOEING SERVICE BULLETIN A3183 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/a3183/file/b44fc7db2675.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.