# Boeing Alert Service Bulletin 737-52A1079: U.S. DOT/FAA - Service Information - 1 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2012-1156; AD 2013-13-12 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-52A1079](https://openairdocs.org/service-documents/boeing/737-52a1079.md) - Title as filed: U.S. DOT/FAA - Service Information - 1 - Pages: 103 - PDF: https://openairdocs.org/files/sha256/c2/72/c272ecc3dcf88322d06d3d02da767d5351c9655867f9a8580246d24657fc077a - Page: https://openairdocs.org/service-documents/boeing/737-52a1079/file/c272ecc3dcf8 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-52A1079 Original Issue: December 16, 1983 Revision 7: December 17, 2010 ATA System: 5231 SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). 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all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1989 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. 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, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery 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. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 1 of 103 4.0 ### Page 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 2 of 103 BOEING SERVICE BULLETIN 737-52A1079 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 ........................................ 2 2 B. Concurrent Requirements ...................................... 2 2 C. Reason ................................................ 2 2 D. Description .............................................. 2 4 E. Compliance .............................................. 2 7 F. Approval ............................................... 3 9 G. Manpower .............................................. 4 0 H. Weight and Balance Changes .................................... 4 1 I. Electrical Load Data ......................................... 4 1 J. References .............................................. 4 1 1. Existing Data: ......................................... 4 1 2. Data supplied with this Service Bulletin: ........................... 4 2 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 4 2 4. Process Data: ......................................... 4 2 K. Publications Affected ........................................ 4 3 L. Interchangeability and Intermixability of Parts ........................... 4 3 2. MATERIAL INFORMATION ........................................ 4 5 A. Material - Price and Availability ................................... 4 5 B. Industry Support Information .................................... 4 5 C. Parts Necessary For Each Airplane ................................. 4 6 1. Kits/Parts: ........................................... 4 6 2. Parts and Materials Supplied by the Operator: ........................ 5 2 3. Parts Modified and Reidentified: ............................... 5 4 4. Parts Removed and Not Replaced: .............................. 5 4 D. Parts Necessary to Change Spares ................................. 5 4 E. Special Tooling - Price and Availability ............................... 5 4 F. Special Tooling Necessary to do this Service Bulletin ....................... 5 5 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 5 7 A. GENERAL INFORMATION ..................................... 5 7 B. WORK INSTRUCTIONS ....................................... 5 8 FIGURE 1: AFT CARGO DOOR INSPECTION .............................. 6 6 FIGURE 2: CORNER INSPECTION AND REWORK ........................... 7 0 FIGURE 3: LOWER BEAM REPAIR - FORWARD END ......................... 7 2 FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END ..................... 7 7 FIGURE 5: LOWER BEAM REPAIR - AFT END ............................. 8 2 FIGURE 6: REPAIR PARTS - LOWER BEAM AFT END ......................... 8 7 FIGURE 7: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL INSPECTION ................................. 8 9 FIGURE 8: AFT CARGO DOOR - LOWER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL INSPECTION .......................................... 9 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 3 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 4 FIGURE 9: AFT CARGO DOOR - UPPER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL INSPECTION ................................. 9 5 FIGURE 10: AFT CARGO DOOR - UPPER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL INSPECTION .......................................... 9 8 FIGURE 11: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL INSPECTION FOR AIRPLANES WITH LOWER BEAM OUTER 'T' CHORD REPAIR INSTALLED ON THE FORWARD END ...................... 1 0 1 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 4 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-52A1079Original Issue: December 16, 1983 Revision 7: December 17, 2010 ATA System: 5231 SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION More work is necessary on airplanes that have not accomplished the repair or preventive modification in accordance with previous releases of this service bulletin. Do an ultrasonic inspection for cracks in the upper and lower corner frames and a HFEC inspection for cracks in the upper and lower cross beams at the revised time specified in Paragraph 1.E., Compliance. More work is necessary on airplanes that have repair angles 65C25180-9, -43, -10, -11 or -12 installed in accordance with previous issues of this service bulletin. Do the work in Paragraph 3.B., Work Instructions, Part V - Corner Inspection and Rework in accordance with Revision 7 of this service bulletin at the revised time specified in Paragraph 1.E., Compliance. More work is necessary on airplanes that have accomplished the repair or preventive modification of the upper or lower cross beams in accordance with previous releases of this service bulletin. Do supplemental structural inspections of the cross beams at the times specified in Paragraph 1.E., Compliance. These supplemental structural inspections provide compliance with 14 CFR 26.43 (c). Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2000-06-13 R1 supersedes Airworthiness Directive (AD) 98-25-06. No new airplanes have been added or removed from the effectivity of this bulletin. REASON FOR REVISION This revision is sent to: — Remove the option for repeat inspections and add a High Frequency Eddy Current (HFEC) inspection for cracks in the beam. — Remove the option to repair the upper edge frame using a Structural Repair Manual (SRM) procedure. — Replace the HFEC inspection of the frames with an ultrasonic inspection. — Inform operators that the corner reinforcing angles given in previous releases of this service bulletin have been superseded by corner reinforcing angles with an increased edge margin. — Inform operators that this revision provides supplemental structural inspections in compliance with 14 CFR 26.43 (c). — Change the Lower Beam Outer 'T' Chord Repair on the forward end of the lower beam to include a joggle of the replacement 'T' Chord. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 5 of 103 ### Page 6 — Change the heat treatment of the replacement 'T' Chord A to 2024-0. — Instruct operators to identify the aft cargo door part number which is currently installed on each airplane in accordance with the original issue of Boeing Service Bulletin 737-52A1153 before further work is done. — Instruct operators to also accomplish all applicable actions in accordance with the original issue of Service Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance, if any cracks are found. These sections were changed: 1. The Summary Background and Action sections are updated. 2. Summary illustration - Reinforcement angles are added to the lower corners of the aft cargo door. 3. Paragraph 1.C., Reason is updated. 4. Paragraph 1.D., Description is updated. 5. Paragraph 1.E., Compliance - The compliance information is changed. 6. Paragraph 1.F, Approval - An Alternative Method of Compliance (AMOC) statement is added. Also, supplemental structural inspection information is added. 7. Paragraph 1.G., Manpower - The manpower information is updated. 8. Paragraph 1.H., Weight and Balance Changes - The SRM repair is removed from the table. 9. Paragraph 1.J., References - Non Destructive Test (NDT) Manual references, reference service bulletin numbers and Federal Aviation Administration (FAA) Airworthiness Directives (AD) are added. Supplemental Structural Inspection Document numbers are also added. SRM 51-40-3 reference is removed. 10. Paragraph 1.K., Publications Affected - A statement for Damage Tolerance Based Structural Inspections is added. 11. Paragraph 2.C.1., Kits/Parts - Replacement parts are added to one kit table. 12. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - Fasteners are added to the table for the repair parts. 13. Paragraph 3.A., General Information - Note added, reference the use of the words "refer to" and "in accordance with". 14. Paragraph 3.B., Work Instructions - Supplemental Structural Inspections are added. Also, the option to repair the upper edge frame using an SRM procedure is removed. 15. Figures 1 through 5 are updated. 16. Figures 7 through 11 are added to provide Supplemental Structural Inspections. Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 6 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 7 Pages with no vertical lines have no important changes. REVISION HISTORY December 16, 1983Original Issue: December 15, 1988Revision 1: July 20, 1989Revision 2: May 17, 1990Revision 3: February 21, 1991Revision 4: May 16, 1996Revision 5: November 18, 1999Revision 6: December 17, 2010Revision 7: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 7 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 8 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 8 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT BLANK PAGE ### Page 9 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-52A1079Original Issue: December 16, 1983 Revision 7: December 17, 2010 ATA System: 5231 SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification 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 Based on a structural review of the 737 airplane, incorporation of the modification in accordance with this service bulletin is recommended on aging airplanes. As of 1996, several operators had reported cracks 0.75 to 20 inches long in the forward and aft lower corner of the aft cargo door frames. The airplanes had 10,100 to 38,000 flight hours and 14,000 to 54,000 flight cycles. In addition, some of the doors had a cracked web in the beam common to the forward lower stop fitting, approximately 3 inches aft of the fitting. In some of the cases, the frame and beam cracks were discovered after the airplane had experienced pressurization problems. Cracking is caused by fatigue as a result of cabin pressurization cycles. Since 1996, there have been additional reports of cracked frames and cracked beam webs. One airplane with 86,400 hours and 35,400 flight cycles experienced a rapid decompression caused by an approximately 12 inch long crack in the aft lower frame corner. The lower beam web and outer 'T' chord were also cracked. Since 1996, there have also been at least two reports of cracking in the lower beam outer "T" chord. One airplane had only the outer "T" chord cracked and had about 63,800 flight hours and 66,500 flight cycles. On the other airplane, the frame and "T" chord were cracked all the way through. The inspection, repair and preventive modification of cross beam D on the aft cargo door is the subject of the original issue of Boeing Service Bulletin 737-52-1154 . The Federal Aviation Administration (FAA) has issued an Airworthiness Directive (AD) which requires incorporation of Revision 5 or 6 of this bulletin. Boeing Service Related Problem (SRP) 737-SRP-52-0077 is related to this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 9 of 103 ### Page 10 ACTION Identify the aft cargo door assembly part number which is currently installed on each airplane in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is found to be from an airplane in the line number range greater than 873, accomplish all applicable actions in accordance with Service Bulletin 737-52A1153 , Original Issue. For Groups 1, 2 and 3 airplane doors: If an airplane is found to have a door configuration that was delivered between line numbers 6 and 873, inclusive, do the following: Do an inspection for cracks in the forward and aft frames at the upper and lower corners. Use visual and ultrasonic inspection techniques to look for cracking in the radius of the frames. Also, do a HFEC inspection for cracking in the lower and upper beam web and outer "T" chord. For airplanes that have previously installed reinforcement angle 65C25180-9, -43, -10, -11 or -12, do an inspection for adequate edge margin and cracks. For airplanes that have previously installed repairs or modifications to the upper or lower cross beam, do supplemental structural inspections at the times given in Paragraph 1.E., Compliance . These supplemental structural inspections provide compliance with 14 CFR 26.43 (c). The modification requires installation of a steel reinforcement angle in each corner of the door and the installation of a web doubler on the upper and lower beams. In addition, if any cracks are found, accomplish all applicable actions in accordance with the original issue of Service Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance . EFFECTIVITY 737-200, -200C, -300, and -400 series airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. COMPLIANCE See Paragraph 1.E., Compliance. Federal Aviation Administration (FAA) Airworthiness Directive AD 90-06-02, AD 98-25-06, AD 98-11-04 R1, AD 2000-06-13 R1, AD 2008-08-23 and AD 2008-09-13 are related to this service bulletin. INDUSTRY SUPPORT INFORMATION This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether you ever filed a warranty claim with Boeing on this service bulletin. MANPOWER See Paragraph 1.G., Manpower. MATERIAL INFORMATION Refer to Paragraph 2.A., Material - Price and Availability. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 10 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 11 (OCR) BOEING SERVICE BULLETIN 737-52A1079 ALERT ALERT STA STA 1016 907 STA 787 logoooopo REINFORCEMENT ANGLES (4 PLACES) FWD INBD TYPICAL FRAME CRACK TYPICAL'T' CHORD CRACK TYPICAL WEB CRACK BEAM WEB STOP FITTING BEAM OUTER 'T' CHORD FRAME HOLID INBD DOOR FRAME TYPICAL FRAME CRACK 752670 VIEW A-A Original Issue: December 16, 1983 Revision 7: December 17, 2010 737-52A1079 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 103 ### Page 12 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 12 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT BLANK PAGE ### Page 13 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-52A1079 Original Issue: December 16, 1983 Revision 7: December 17, 2010 ATA System: 5231 SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes This service bulletin is for the airplanes shown below. Refer to Service Bulletin Index Document D6-19567, Part 3 for Airplane Variable Number, Line Number, and Serial Number data. DESCRIPTIONCONFIGURATIONGROUP 737-200 and -200C airplanes, line numbers 6 - 571. These airplanes are the same as Group 2 airplanes except for slightly different door stop cutouts in the frame which required different repair kit parts. -1 737-200 and -200C airplanes, line numbers 510 - 873. These airplanes are the same as Group 1 airplanes except for slightly different door stop cutouts in the frame which required different repair kit parts. -2 737-200/-200C/-300 and -400 airplanes, line numbers 874 - 1642. These airplanes require an inspection to determine the aft cargo door configuration. -3 Airplane Models: 737-200, 737-200C, 737-300, 737-400 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 13 of 103 ### Page 14 GroupVariable Number 1PG001 - PG075 1PG199 1PG201 - PG230 1PG251 - PG255 1PG271 - PG279 1PG301 - PG314 1PG331 - PG332 1PG351 - PG356 1PG375 1PG401 - PG403 1PG431 - PG442 1PG471 - PG475 1PG501 - PG505 1PG571 - PG586 1PG621 - PG630 1PG651 - PG652 1PG701 - PG705 1PH001 1PH011 - PH013 1PH021 - PH024 1PH701 - PH715 1PH731 - PH732 1PH741 - PH743 1PJ001 - PJ006 2PJ007 - PJ009 1PJ031 - PJ032 1PJ071 - PJ072 1PJ101 - PJ111 2PJ112 - PJ119 1PJ201 - PJ219 1PK026 - PK029 1PK041 - PK053 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 14 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 15 GroupVariable Number 1PK061 - PK070 1PK081 2PK082 1PK091 - PK099 1PK101 - PK103 1PK111 - PK120 1PK141 - PK146 2PK201 - PK204 1PK211 - PK212 2PK213 - PK215 3PK216 - PK220 1PK221 2PK222 - PK223 1PK231 - PK235 2PK236 - PK240 1PK241 1PK251 - PK258 1PK271 - PK273 2PK274 1PK281 2PK282 - PK289 1PK291 1PK301 - PK306 2PK307 - PK310 1PK311 - PK314 2PK315 - PK318 1PK341 1PK351 - PK352 2PK353 - PK361 1PK391 2PK431 - PK433 1PK451 2PK452 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 15 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 16 GroupVariable Number 1PK461 - PK465 2PK466 - PK469 2PK495 1PK501 2PK502 - PK503 3PK504 1PK511 2PK512 - PK514 3PK515 3PK519 2PK521 - PK524 3PK525 - PK528 2PK541 - PK564 3PK565 2PK581 2PK591 - PK599 2PK601 - PK617 2PK621 - PK630 3PK631 - PK637 2PK641 - PK642 2PK661 - PK663 3PK664 - PK666 2PK671 - PK678 3PK679 - PK681 2PK691 - PK696 3PK697 2PK711 - PK716 2PK731 - PK749 3PK750 - PK765 2PK771 - PK779 2PK801 - PK802 3PK803 - PK804 2PK819 - PK826 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 16 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 17 GroupVariable Number 3PK827 2PK830 2PK861 - PK863 2PK871 - PK874 2PK881 - PK884 2PK901 - PK932 3PK933 - PK938 2PK971 - PK974 1PL001 2PL002 - PL023 3PL024 - PL028 2PL061 2PL081 2PL101 - PL112 3PL113 2PL151 2PL171 3PL172 2PL201 - PL203 3PL221 2PL401 - PL412 3PL413 - PL417 2PL421 2PL441 2PL451 - PL454 3PL455 - PL456 2PL471 2PL491 2PL501 - PL506 2PL551 - PL561 3PL562 2PL581 2PL601 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 17 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 18 GroupVariable Number 3PL602 - PL603 3PL611 3PL621 - PL626 3PL631 - PL632 1PL711 - PL712 1PL716 - PL743 2PL744 - PL745 3PL746 - PL747 1PL756 1PL758 1PL761 - PL767 2PL768 - PL770 1PL781 - PL782 2PL783 3PL784 - PL788 1PL793 1PL801 - PL803 2PM001 - PM002 3PM003 - PM006 3PM016 - PM017 2PM021 - PM023 3PM051 - PM066 2PM101 - PM104 3PM105 - PM119 2PM141 - PM142 3PM171 3PM181 3PM251 - PM255 3PM281 - PM283 3PM381 3PN001 - PN002 3PN021 - PN043 3PN081 - PN086 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 18 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 19 GroupVariable Number 3PN101 - PN117 3PN131 - PN163 3PN401 - PN420 3PN431 - PN433 3PN451 - PN456 3PN471 - PN474 3PN481 3PN491 - PN493 3PN501 - PN502 3PN511 - PN512 3PN521 3PP001 - PP047 3PP101 - PP139 3PP161 - PP169 3PP181 - PP197 3PP201 - PP205 3PP221 3PP231 - PP243 3PP281 - PP286 3PP301 - PP305 3PP351 - PP353 3PP376 - PP384 3PP391 - PP393 3PP401 - PP440 3PP471 - PP475 3PP501 - PP507 3PP521 - PP522 3PP631 - PP634 3PP651 - PP652 3PP671 - PP699 3PP701 - PP733 3PP771 - PP779 3PP801 - PP804 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 19 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 20 GroupVariable Number 3PP821 - PP827 3PP831 - PP848 3PP851 - PP852 3PP861 - PP872 3PP891 - PP899 3PP901 - PP914 3PP931 - PP936 3PP946 - PP948 3PP951 - PP952 3PP961 - PP965 3PP981 - PP984 3PP991 3PQ001 - PQ012 3PQ026 - PQ041 3PQ051 - PQ065 3PQ086 - PQ090 3PQ101 - PQ145 3PQ221 - PQ222 3PQ231 - PQ236 3PQ241 - PQ243 3PQ251 3PV001 - PV010 3PW001 - PW005 3PW061 3PW091 1PX071 1PX701 1PY001 - PY008 1PY021 - PY022 1PY031 1PY036 - PY037 1PY046 - PY048 1PY051 - PY053 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 20 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 21 GroupVariable Number 3PY056 - PY057 1PY101 - PY103 1PY111 - PY113 1PY131 - PY133 2PY134 - PY135 1PY141 - PY143 1PY151 - PY152 2PY153 - PY154 1PY156 - PY157 1PY161 - PY162 1PY166 1PY191 1PY201 1PY221 - PY222 2PY231 2PY241 - PY244 2PY270 1PY271 - PY274 2PY275 1PY281 1PY286 1PY301 - PY304 1PY321 - PY323 1PY341 - PY346 1PY361 - PY362 1PY381 1PY401 3PY409 - PY410 1PY411 2PY421 3PY422 2PY441 2PY451 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 21 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 22 GroupVariable Number 2PY461 - PY462 3PY463 3PY591 - PY595 1PY611 2PY612 2PY621 2PY631 2PY651 3PY671 - PY672 3PY721 3PY741 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 As a result of the FAA sponsored Aging Fleet conference, a 737 Structures Working Group with Airline and Boeing members and FAA observers was formed to review structural service bulletin modifications and recommend selected bulletins for incorporation on aging airplanes. This service bulletin modification has been recommended for incorporation on aging 737 airplanes. Accomplishment of the modification in accordance with this bulletin will reduce the possibility of fatigue cracks in the aft cargo door. Cracks in the aft cargo door frame may propagate and result in an inability to maintain cabin pressurization. As of 1996, several operators had reported cracks 0.75 to 20 inches long in the forward and aft lower corner of the aft cargo door frames. The airplanes had 10,100 to 38,000 flight hours and 14,000 to 54,000 flight cycles. In addition, some of the doors had a cracked web in the beam common to the forward lower stop fitting, approximately three inches aft of the fitting. In some of the cases, the frame and beam cracks were discovered after the airplane had experienced cabin pressurization problems. Cracking is caused by fatigue as a result of cabin pressurization cycles. Since 1996, there have been additional reports of cracked frames and cracked beam webs. One airplane with 86,400 hours and 35,400 flight cycles experienced a rapid decompression caused by an approximately 12 inch long crack in the aft lower frame corner. The lower beam web and outer "T" chord were also cracked. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 22 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 23 Since 1996, there have also been at least two reports of cracking in the lower beam outer "T" chord. One airplane had only the outer "T" chord cracked and had approximately 63,800 flight hours and 66,500 flight cycles. The other airplane had the outer "T" chord and the frame cracked all the way through. The inspection, repair and preventive modification of cross beam D on the aft cargo door is the subject of the original issue of Boeing Service Bulletin 737-52-1154 . Boeing is aware that doors requiring inspection, repair, and modification in accordance with this service bulletin may be used on airplanes (Group 3 airplanes) originally delivered with doors which do not require the service bulletin inspections or modifications. This service bulletin addresses these doors. The Federal Aviation Administration (FAA) has issued an Airworthiness Directive (AD) which requires incorporation of Revision 5 or 6 of this bulletin. Revision 1 was issued to advise operators that some aft cargo door corner reinforcement kits may have been delivered with an incorrectly manufactured angle that if installed may have four fasteners with inadequate edge margin. New Kit and supplemental kit information was provided and updated drawings provided. Revision 2 of this bulletin was issued to provide the recommendations of the Aging Fleet 737 Structures Working Group and to lower the inspection threshold on the door frames and beams from 25,000 flight cycles to 12,000 flight cycles. Revision 3 of this service bulletin was issued to advise operators that installation of reinforcement angle 65C25180-9 or -43 may result in a short edge margin condition. This condition may appear between the angle and fastener locations common to the outer skin. New kit and part information were provided, along with updated drawings. Revision 4 of this service bulletin was sent to add the circle note indicators to Figure 2 that were accidentally ignored when Revision 3 was released. Indicators were added to the text notes and locations in the illustration were corrected. Revision 5 of this service bulletin was sent to advise operators that installation of reinforcement angles 65C25180-10, -11 and -12, included in corner reinforcement kits 65C25180-3, -44 and -46, can result in a short edge margin condition. Also, the minimum allowable edge margin was changed from 0.38 inch to 0.32 inch. This service bulletin revision provided corner reinforcement kit 65C25180-47 and supplemental kit 65C25180-51 that included reinforcement angles with sufficient material added to both flanges. The new reinforcement angles were for the upper aft, lower forward and lower aft corners. New kit and part information were provided, along with updated drawings. Revision 6 of this service bulletin was sent to: — Add Group 3 airplanes to the effectivity. These airplanes may have a Group 1 or 2 airplane aft cargo door installed on them which requires inspection, repair, or modification. — Add a High Frequency Eddy Current (HFEC) inspection for cracks in the frames of doors that do not have steel reinforcement angles. — Add an inspection for cracks in the upper and lower beam outer 'T' chord of doors that do not have the lower beam reinforcement doubler. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 23 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 24 — Add repair instructions for the lower beam outer "T" chord. — Remove the two inch stop-drilled crack allowable. — Update Paragraph 1.F., Approval, to make Revisions 4, 5, and 6 of this service bulletin an Alternative Method of Compliance (AMOC) to AD 90-06-02, and to make Revision 6 of this service bulletin an AMOC to AD 98-25-06. Revision 7 of this service bulletin is sent to: — Remove the option for repeat inspections and add a High Frequency Eddy Current (HFEC) inspection for cracks in the beam. — Remove the option to repair the upper edge frame using a Structural Repair Manual (SRM) procedure. — Replace the HFEC inspection of the frames with an ultrasonic inspection. — Inform operators that the corner reinforcing angles given in previous releases of this service bulletin have been superseded by corner reinforcing angles with an increased edge margin. — Inform operators that this revision provides supplemental structural inspections in compliance with 14 CFR 26.43 (c). — Change the Lower Beam Outer 'T' Chord Repair on the forward end of the lower beam to include a joggle of the replacement 'T' Chord. — Change the heat treatment of the replacement 'T' Chord A to 2024-0. — Instruct operators to identify the aft cargo door part number which is currently installed on each airplane in accordance with the original issue of Boeing Service Bulletin 737-52A1153 before further work is done. — Instruct operators to also accomplish all applicable actions in accordance with the original issue of Service Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance, if any cracks are found. Boeing Service Related Problem (SRP) 737-SRP-52-0077 is related to this service bulletin. D. Description Identify the aft cargo door assembly part number which is currently installed on each airplane in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is found to be from an airplane in the line number range greater than 873, accomplish all applicable actions in accordance with Service Bulletin 737-52A1153 , Original Issue. For Groups 1, 2 and 3 airplane doors: If an airplane is found to have a door configuration that was delivered between line numbers 6 and 873, inclusive, do the following: Do an inspection for cracks in the forward and aft frames at the upper and lower corners. Use visual and ultrasonic inspection techniques to look for cracking in the radius of the frames. Also, do a HFEC inspection for cracking in the web and outer "T" chord of the upper and lower beams. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 24 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 25 — If a crack is found in an upper or lower corner frame web, replace the damaged frame and install the preventive modification kits on the frames and on the beams. — If a crack is found in the web of the upper or lower beam, trim out the crack and install the repair kits on the frames and on the beams. The frame preventive modification kit requires the installation of a steel reinforcement angle in each corner of the door on the exterior of the door frame under the outer skin and door seal retainer. The beam preventive modification/repair kit requires the installation of a bent-up web doubler on the forward and aft ends of the beam. — If a crack is found in the web and "T" chord of the lower beam, or in the outer "T" chord only, trim out the web crack and do the repair in accordance with this bulletin. The repair for the aft end of the lower beam requires the installation of the preventive modification kit, two splice angles (operator supplied), and a new section of "T" chord (operator supplied). The repair for the forward end of the lower beam requires the installation of new repair parts which are all operator supplied: a new bent-up repair doubler, fillers, splice angles, and a new section of "T" chord. — If a crack is found in the "T" chord of the upper beam, contact Boeing. — If no cracks are found in the frames or beams, do the preventive modification in accordance with this service bulletin. — Do Supplemental Structural Inspections at the times shown in Paragraph 1.E., Compliance . — In addition, if any cracks are found, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . If you have previously installed reinforcement angles 65C25180-9 or -43, -10, -11 or -12, do an inspection for adequate edge margin and cracks. If cracks are found or the edge margin is not adequate, replace the angles with 65C25180-52, 53, 54 and 55. If no cracks are found and the edge margins are adequate, no further action is required on the retrofit angles in accordance with this service bulletin. More work is necessary on airplanes that have accomplished the repair or preventive modification of the upper or lower cross beams in accordance with previous releases of this service bulletin. Do supplemental structural inspections of the cross beams at the times specified in Paragraph 1.E., Compliance. These supplemental structural inspections provide compliance with 14 CFR 26.43 (c). Airplane effectivity is divided into three groups. Group 1 and 2 airplanes are 737-200 and -200C airplanes line numbers 6 through 873. Group 1 airplane doors are the same as Group 2 airplane doors except for slightly different door stop cutouts in the frame which required different repair kit parts. Group 3 airplanes are 737-200, -200C, -300, and -400 airplanes line numbers 874 through 1642. Based on a structural review of the 737 airplane, the modifications in accordance with the inspections of this service bulletin should be accomplished within 4,500 flight cycles from the date of Revision 7 of this service bulletin. Revision 1 - Airplanes previously modified with corner reinforcement kit 65C25180-3 require inspection to ensure that a correctly configured angle was installed. If an incorrectly configured angle was installed inspection is required to ensure that adequate edge margin exists for attach fasteners common to reinforcement angle and the two forward upper door stops. If an inadequate edge margin exists inspection is required for cracks in the angle. If cracks are found, the angle is replaced. If no cracks are found, repeat inspections at every structural inspection period (D check) intervals until the angle is replaced with a correctly configured angle, in accordance with Revision 3. Revision 2 - Airplanes modified in accordance with Part II of the Accomplishment Instructions of Revision 1 of this service bulletin do require additional work, in accordance with Revision 3. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 25 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 26 Revision 3 or 4 - Airplanes previously modified with corner reinforcement kit 65C25180-44 or have had angle 65C25180-9 or -43 installed required additional inspection to ensure that adequate edge margin exists for attach fasteners common to reinforcement angle and outer skin. If inadequate edge margin exists, inspect angle for cracks. If cracks were found, replace angle. If no cracks were found, repeat inspection every Structural Inspection Period (D check) until angle is replaced with 65C25180-45 to provide proper edge margin. Revision 5 - Airplanes previously modified with the installation of angles 65C25180-10, 65C25180-11, and 65C25180-12 will require additional inspections to ensure that adequate edge margin exists for attach fasteners common to door stop fittings and reinforcement angle. If inadequate edge margin exists, inspect angle for cracks. If cracks are found, replace angle. If no cracks are found, repeat inspection every Structural Inspection Period (D check) until angles are replaced with 65C25180-48, 65C25180-49 and 65C25180-50 to provide proper edge margin. Revision 6 - Airplanes modified in accordance with Revision 5 of this service bulletin require no more work. Revision 7 - More work is necessary as follows: — More work is necessary on airplanes that have not accomplished the repair or preventive modification in accordance with previous releases of this service bulletin. Do an ultrasonic inspection for cracks in the upper and lower corner frames and a HFEC inspection for cracks in the upper and lower cross beams at the revised time specified in Paragraph 1.E., Compliance. — More work is also necessary on airplanes that have repair angles 65C25180-9, -43, -10, -11 or -12 installed in accordance with previous issues of this service bulletin. Do the work in Paragraph 3.B., Work Instructions, Part V - Corner Inspection and Rework in accordance with Revision 7 of this service bulletin at the revised time specified in Paragraph 1.E., Compliance. — More work is necessary on airplanes that have accomplished the repair or preventive modification of the upper or lower cross beams in accordance with previous releases of this service bulletin. Do supplemental structural inspections of the cross beams at the times specified in Paragraph 1.E., Compliance. Prior or concurrent incorporation of the Service Bulletins listed below are suggested on commonly affected airplanes. These bulletins have some common access requirements: 737-52-1051 - Lower Cargo Door Latch Spring Relocation and Replacement. 737-52-1063 - Lower Cargo Door Hinge Attach Bolt Inspection. 737-52-1065 - Forward and Aft Cargo Door Stop Fittings Inspection and Replacement. 737-52-1154 - Aft Cargo Door Cross Beam D Inspection, Repair and Preventive Modification. This service bulletin is listed in Boeing Document D6-38505. The work in this service bulletin is done in the maintenance zone(s) given below. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 26 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 27 Group 1-3: Affected Maintenance Zones ZoneModel 2-19737-200, 737-200C Group 3: Affected Maintenance Zones ZoneModel 219737-300, 737-400 E. Compliance Federal Aviation Administration (FAA) Airworthiness Directives AD 90-06-02 , AD 98-25-06 , AD 98-11-04 R1, AD 2000-06-13 R1, AD 2008-08-23 and AD 2008-09-13 are related to this service bulletin. Accomplish the work in accordance with Revision 7 of this service bulletin at the times shown in the tables that follow. Table 1: Determination of door configuration (all airplanes), and High Frequency Eddy Current (HFEC) and Ultrasonic Inspections for airplanes not modified and not repaired in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6 of this service bulletin. Compliance TimeActionCondition Within 4,500 door flight cycles from the date of Revision 7 to this Ser- vice Bulletin. (a) Determine door configuration in accordance with Service Bulletin 737-52A1153, Original Issue, Paragraph 3.B.1. All Groups. At the time given in 737-52A1153, Original Issue. Accomplish all applicable actions in accordance with the original issue of Service Bulletin 737- 52A1153. Door found to be from an airplane with a line number range greater than 873. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. (a) Do one-time HFEC and ultrasonic inspections of the upper and lower corner frames and the upper and lower cross beams for cracks in ac- cordance with Work Instructions, Part I - Access and Part II - Inspection. (a) Doors found to be from an airplane in the line number range between 6 and 873 without either the Modifi- cation or Repair accomplished in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5 and 6 of this service bulletin. Before further flight. (a)Do the modification in accordance with Work Instructions, Part III - Preventive Modification. No crack(s) found in the upper and lower corner frames or the upper and lower cross beams. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 27 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 28 Table 1: Determination of door configuration (all airplanes), and High Frequency Eddy Current (HFEC) and Ultrasonic Inspections for airplanes not modified and not repaired in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6 of this service bulletin. Compliance TimeActionCondition Before further flight.Do the beam repair in accordance with Work Instructions. Crack(s) found in the upper or lower beam. Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. (a) Before further flight.Replace the frame. Do the frame modification in accordance with Work Instructions, Part III - Preventive Modification. Crack(s) found in an upper corner frame. Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. (a) Before further flight.Replace the damaged frame in accordance with Work Instructions, Part IV - Lower Frame Replacement for Aft and Forward Frames and do the modification in accordance with Work Instructions, Part III - Preventive Modification. Crack(s) found in a lower corner frame. Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. (a) (a) NOTE: This is a new requirement of Revision 7 of this service bulletin. Compliance requirements of AD 90-06-02 amendment 39-6489 and AD 2000-06-13 R1 amendment 39-12317 still apply. Table 2: Supplemental Inspection for airplanes with reinforcement angles 65C25180-9, -43, -10, -11 or -12 installed Compliance TimeActionCondition Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. (a) Inspect lower corner frames to determine if door has reinforcement angles 65C25180-9, -43, - 210, -11, or -12 installed in accordance with the original issues, Revision 1, 2, 3 or 4 of this service bulletin. All Groups. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. (a) Do a one-time general visual inspection for edge margin and detailed inspection for cracks in accordance with Work Instructions, Part V - Corner Inspection and Rework. Airplanes with reinforcement angles 65C25180-9, -43, -10, -11 or -12 installed in accordance with the original issue, Revision 1, 2, 3 or 4 of this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 28 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 29 Table 2: Supplemental Inspection for airplanes with reinforcement angles 65C25180-9, -43, -10, -11 or -12 installed Compliance TimeActionCondition -No further action is required.Airplanes without reinforcement angles 65C25180-9, -43, -10, -11 or -12 installed. Before further flight. (a)Replace the corner reinforcement angle in ac- cordance with Work Instructions, Part III - Pre- ventive Modification. Crack(s) found in corner reinforce- ment angle or edge margin is not adequate. Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. (a) -No further action is required.No crack(s) found in corner rein- forcement angles and edge margin is adequate. (a) NOTE: This is a new requirement of Revision 7 of this service bulletin. Compliance requirements of AD 90-06-02 amendment 39-6489 and AD 2000-06-13 R1 amendment 39-12317 still apply. Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the preventive modifica- tion is installed, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the for- ward end of the low- er cross beam in ac- cordance with the Original Issue or Re- visions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are known. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 29 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 30 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the preventive modifica- tion is installed. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the for- ward end of the low- er cross beam in ac- cordance with the Original Issue or Re- visions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 30 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 31 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the preventive modifica- tion is installed, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the aft end of the lower cross beam in accor- dance with the Origi- nal Issue or Revi- sions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the preventive modifica- tion is installed. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the aft end of the lower cross beam in accor- dance with the Origi- nal Issue or Revi- sions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are not known. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 31 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 32 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the preventive modifica- tion is installed, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the for- ward end of the up- per cross beam in accordance with the Original Issue or Re- visions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before urther flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 32 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 33 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the preventive modifica- tion is installed. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the for- ward end of the up- per cross beam in accordance with the Original Issue or Re- visions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the preventive modifica- tion is installed, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the aft end of the upper cross beam in accor- dance with the Origi- nal Issue or Revi- sions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are known. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 33 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 34 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the preventive modifica- tion is installed. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a pre- ventive modification installed on the aft end of the upper cross beam in accor- dance with the Origi- nal Issue or Revi- sions 1, 2, 3, 4, 5, 6 or 7 of this service bulletin and the door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the lower beam outer "T" chord repair is in- stalled, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a low- er beam outer "T" chord repair installed on the forward end of the lower cross beam in accordance with this revision of this service bulletin and the door flight cycles are known. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 34 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 35 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the lower beam outer "T" chord repair is in- stalled. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a low- er beam outer "T" chord repair installed on the forward end of the lower cross beam in accordance with this revision of this service bulletin and the door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Before 56,000 total door flight cycles, or, Within 18,000 door flight cycles after the lower beam outer "T" chord repair is in- stalled, whichever comes first. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a low- er beam outer "T" chord repair installed on the aft end of the lower cross beam in accordance with Re- vision 6 or 7 of this service bulletin and the door flight cycles are known. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 35 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 36 Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per this Revision of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. 4,500 door flight cycles. Within 4,500 door flight cycles from the date of Revision 7 to this ser- vice bulletin. Within 4,500 door flight cycles after the lower beam outer "T" chord repair is in- stalled. Do a detailed inspection and a LFEC inspection of the cross beam for cracks in accordance with Work Instructions, Part VII - Supplemental Structural Inspections. Airplanes with a low- er beam outer "T" chord repair installed on the aft end of the lower cross beam in accordance with Re- vision 6 or 7 of this service bulletin and the door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the re- pair. Crack(s) found. -Before further flight.Accomplish actions in ac- cordance with Tables 1 through 4 of Service Bul- letin 737-52-1154, Original Issue, Paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 36 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 37 Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 17,000 door flight cycles. Within 17,000 door flight cycles from the date of Revision 7 to this service bulletin. 66,000 door flight cy- cles after installation of the Lower Beam Outer 'T' Chord Repair on the forward end of the low- er cross-beam or 100,000 total door flight cycles, whichever comes first. Do Open-Hole HFEC in- spections of the forward end of the lower cross beam for cracks in accor- dance with Work Instruc- tions, Part VIII - Forward End Lower Beam Outer 'T' Chord Repair Supple- mental Inspections. Airplanes with a Lower Beam Outer 'T' Chord Repair in- stalled on the for- ward end of the lower beam in ac- cordance with Revi- sion 6 of this Ser- vice Bulletin and the door flight cy- cles since the re- pair are known. -Before further flight.Contact Boeing for repair instructions and do the repair. Crack(s) found. -Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Para- graph 1.E., Compliance. 17,000 door flight cycles. 17,000 door flight cy- cles from the date of Revision 7 to this bul- letin. 100,000 total door flight cycles. Do Open-Hole HFEC in- spections of the forward end of the lower cross beam for cracks in accor- dance with Work Instruc- tions, Part VIII - Forward End Lower Beam Outer 'T' Chord Repair Supple- mental Inspections. Airplanes with a Lower Beam Outer 'T' Chord Repair in- stalled on the for- ward end of the lower beam in ac- cordance with Revi- sion 6 of this Ser- vice Bulletin and the door flight cy- cles since the re- pair are not known. -Before further flight.Contact Boeing for repair instructions and do the repair. Crack(s) found. -Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Para- graph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 37 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 38 Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 17,000 door flight cycles. 17,000 door flight cycles from the date of Revi- sion 7 to this bulletin. Do Open-Hole HFEC in- spections of the forward end of the lower cross beam for cracks in accor- dance with Work Instruc- tions, Part VIII - Forward End Lower Beam Outer 'T' Chord Repair Supple- mental Inspections. Airplanes with a Lower Beam Outer 'T' Chord Repair in- stalled on the for- ward end of the lower beam in ac- cordance with Revi- sion 6 of this Ser- vice Bulletin and the total door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the repair. Crack(s) found. -Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Para- graph 1.E., Compliance. 4,500 door flight cycles. Within 17,000 door flight cycles from the date of Revision 7 of this Service Bulletin. Before 56,000 total door flight cycles. Do a detailed inspection of the outer skin in the inspection area for cracks in accordance with Work Instructions, Part VIII - Forward End Lower Beam Outer 'T' Chord Repair Supple- mental Inspections. Airplanes with a Lower Beam Outer "T" Chord Repair installed on the for- ward end of the lower beam in ac- cordance with Revi- sion 6 of this Ser- vice Bulletin and the door flight cy- cles are known. -Before further flight.Contact Boeing for repair instructions and do the repair. Crack(s) found. -Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Para- graph 1.E., Compliance. Bulletin BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 38 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 39 Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin Repeat Inter- val (Not to Exceed) Compliance Time (Whichever Occurs Later)ActionCondition 4,500 door flight cycles. 4,500 door flight cycles from the date of Revi- sion 7 to this bulletin. Do a detailed inspection of the outer skin in the inspection area for cracks in accordance with Work Instructions, Part VIII - Forward End Lower Beam Outer 'T' Chord Repair Supple- mental Inspections. Airplanes with a Lower Beam Outer "T" Chord Repair installed on the for- ward end of the lower beam in ac- cordance with Revi- sion 6 of this Ser- vice Bulletin and the total door flight cycles are not known. -Before further flight.Contact Boeing for repair instructions and do the repair. Crack(s) found. -Before further flight.Accomplish actions in accordance with Tables 1 through 4 of Service Bulletin 737-52-1154, Original Issue, Para- graph 1.E., Compliance. F. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the modification defined in Revision 3, 4, 5, 6 and 7 of Service Bulletin 737-52A1079, Door - Aft Cargo, Frame and Beam Inspection, Repair and Modification as an alternative method of compliance to the requirements of paragraph (a) of AD 90-06-02 , amendment 39-6489. This alternative method of compliance applies only to the modification specified in Boeing document D6-38505 for Service Bulletin 737-52A1079. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 39 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 40 For airplanes identified in this service bulletin, Revision 7, the repairs and/or modifications of this service bulletin have been reviewed as required by paragraphs (g) and (i) of Airworthiness Directive AD 2008-08-23, paragraphs (g), (h) and (i) of AD 98-11-04 R1, and paragraphs (g) and (i) of AD 2008-09-13. The repairs and/or modifications are found to affect Structurally Significant Item (SSI) F-1 of Supplemental Structural Inspection Documents (SSID) D6-37089, Revisions D and E, and D6-82669, but the F-1 inspections remain effective with the repairs and/or modifications installed. Therefore, an alternative inspection is not necessary for F-1. Do the existing F-1 inspections as required per paragraphs (g), (h) and (i) of AD 2008-08-23, paragraphs (b) and (c) of AD 98-11-04 R1, and paragraphs (g), (h), and (i) of AD 2008-09-13. The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the supplemental inspections defined in paragraph 1.E, Compliance, Tables 3 and 4 of Revision 7 of this service bulletin as an alternative method of compliance (AMOC) to the inspections of SSI F-1 required by paragraphs (g) and (h) of AD 2008-08-23 (SSID D6-37089, Revision E), and paragraphs (g) and (h) of AD 2008-09-13 (SSID D6-82669). The Manager of the FAA Seattle ACO also approves the supplemental inspections defined in paragraph 1.E, Compliance, Tables 3 and 4 of Revision 7 of this service bulletin as a method of compliance to paragraph (g) of AD 98-11-04 R1 (SSID D6-37089, Revision E). This approval applies only to SSI F-1 of the applicable SSID and only for the portions of the upper and lower cross beams of the aft door that have been repaired and/or modified in accordance with this service bulletin. All provisions of AD 2008-08-23, AD 98-11-04 R1, and AD 2008-09-13 that are not specifically referenced in this paragraph remain fully applicable and must be satisfied. In addition, the Manager of the FAA Seattle ACO approves the inspection, repair and modification with the corresponding compliance times specified in Tables 1 and 2 of paragraph 1.E, Compliance, of this service bulletin as an AMOC to the inspections, repairs, and modifications required by paragraphs (a), (c), (d) and (e) of AD 2000-06-13 R1. This AMOC only applies to areas inspected, repaired or modified by this service bulletin. All provisions of AD 2000-06-13 R1 that are not specifically referenced in this paragraph remain fully applicable and must be satisfied. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph (i) of AD 98-11-04 R1, paragraph (l) of AD 2008-08-23, paragraph (l) of AD 2008-09-13, or paragraph (f) of AD 2000-06-13 R1, as applicable. G. Manpower Approximately 180 man hours are required to accomplish this modification per airplane. The following breakdown of manpower requirements is suggested as a guide to assist operators in planning and accomplishing this modification. This estimate is for direct labor performed by an experienced crew. It does not include setup, planning, familiarization, cure time, part fabrication, tool acquisition, or lost time. Factor this estimate as necessary based on your own experience. Elapsed Time (Hours)Man-HoursNumber of PersonsTask 362Access 10202Inspection 721442Modification 5102Restoration 90180TOTAL FOR EACH AIRPLANE BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 40 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 41 Elapsed Time (Hours)Man-HoursNumber of PersonsTask Add 24 man-hours and 12 hours downtime to the total modification for each lower frame that requires replacement. For airplane doors with retrofit angles 65C25180-9, -43, -10, -11 or -12: Approximately 116 man hours and a crew of 2 men are required to accomplish this upper corner reinforcement angle inspection and replacement. Part VII - Supplemental Structural Inspections Elapsed Time (Hours)Man-HoursNumber of PersonsTask 12121Inspection 1212TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes Change in Moment (Pound-Inches) Change in Weight (Pounds) Applicability Modification + 5,319.70+ 6.15- Corner straps and beam doublers Repair No ChangeNo Change- Lower and/or upper beam web repair No ChangeNo Change- Lower beam "T" chord repair I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Engineering Change Memo PRR 33098. b. 737-100/200 Aircraft Maintenance Manual (AMM) 52-09-121, 52-31-0. c. 737-100/200 Structural Repair Manual (SRM) 51-10-2 . d. 737 Non-Destructive Testing (NDT) Manual Part 4, 52-10-02 , Part 6, 51-00-00 , Part 6, 52-30-01 . e. Standard Overhaul Practices Manual (SOPM) 20-41-02 , 20-43-03 . f. Overhaul Manual (OHM) 52-36-12. g. 737 Structural Item Interim Advisory (SIIA) 737-71. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 41 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 42 h. Boeing Service Bulletin 737-52-1051 , 737-52-1063 , 737-52-1065 , 737-52-1154 , 737-52A1153 . i. Boeing Document D6-38505 Structural Modification Program - Model 737-100/-200/-200C. j. Boeing Service Related Problem (SRP) 737-SRP-52-0077 . k. Federal Aviation Administration (FAA) Airworthiness Directive 2000-06-13 R1, 2008-08-23 , 2008-09-13 , 90-06-02 , 98-11-04 R1, 98-25-06 . l. Boeing Document D6-82669 Supplemental Structural Inspection Document Model 737-300/400/500 Airplanes, Original Release. m. Boeing Document D6-37089 Supplemental Structural Inspection Document Model 737-100/200/200C Airplanes, Revisions E and D. n. Boeing Drawing 65C25180. 2. Data supplied with this Service Bulletin: a. Drawings: ADCNDCN/REVSheetTitleDrawing No -C1Frame and Beam Reinforcement Repair - Aft Cargo Door 65C25180 -D2 3B3 4B4 -A5 3B6 -GPL 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number Door Assy - Aft Cargo65-47952 This drawing was used to prepare this service bulletin. This drawing is not necessary to make the specified changes, and is not supplied with this service bulletin. This drawing may not be applicable to all airplane configurations or operators. 4. Process Data: Boeing Process specifications referred to on the drawings are not given in this service bulletin since these procedures are frequently used as standard shop practices. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 42 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 43 K. Publications Affected 1. Publications Chapter-SectionPublication 52-30-2737 Structural Repair Manual OHM 52-36-12Overhaul Manual 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS and new DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin. L. Interchangeability and Intermixability of Parts Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 43 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 44 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 44 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT BLANK PAGE ### Page 45 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, as shown below. Kit availability is shown in the Reorder Lead Time (ROLT). ROLT is calculated from the date Boeing gets the purchase order. Improved flow times may be possible if necessary to support operator's planned modification schedule. Therefore, operators are requested to include planned dates of incorporation on their purchase orders. Unit Price thru Sept. 30, 1996 ROLT (weeks) NameKit Number Inactive for procurementModification Kit65-91434-3 $ 4,530.0029Modification Kit65-91434-4 $ 286.0026Supplemental Kit65-91434-5 $ 737.0022Repair Kit65C25180-5 $ 973.0024Repair Kit65C25180-6 $ 764.0022Repair Kit65C25180-7 $ 967.0023Repair Kit65C25180-8 $ 174.0033Angle65C25180-45 Inactive for procurementReinforcement Kit65C25180-46 $ 2,768.0029Reinforcement Kit65C25180-47 The prices quoted are subject to the terms and condition of Boeing's standard purchase order acknowledgment. Quotations are subject to acceptance within 180 days from date hereon. Prices quoted in United States Dollars. Terms: Net 30 days. Address purchase orders and correspondence pertaining to this quotation to Director of Spares, and refer to this service bulletin number. B. Industry Support Information This service bulletin was first released before October of 1994. Thus industry support for affected airplanes depends upon whether you ever filled a warranty claim with Boeing on this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 45 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 46 C. Parts Necessary For Each Airplane 1. Kits/Parts: To get the kits shown below, refer to Paragraph 2.A., Material - Price and Availability. NOTE: Modification top kit is divided into subkits for convenience of installation. Only one top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary to modify each airplane. 1. 2. An applicable forward and aft frame repair kit should be available during door modification. AFT CARGO DOOR MODIFICATION TOP KIT65-91434 --1-2-3-4-5 NamePart NumberQuantity Modification Top Kit65-91434-1 (a)-.... Modification Top Kit65-91434-2 (a).-... Modification Top Kit65-91434-3 (b)..-.. Modification Top Kit65-91434-4 (c)...-. Modification Suppl Kit65-91434-5 (d)....- Corner Reinforcement Kit65C25180-31.... Lower Beam Reinforcement Kit65C25180-41111. Upper Beam Reinforcement Kit65C25180-421111. Corner Reinforcement Kit65C25180-44.1... Corner Reinforcement Kit65C25180-46..1.. Corner Reinforcement Kit65C25180-47...1. Corner Reinforcement Suppl Kit65C25180-51....1 (a) Inactive for procurement. Rework 65-91434-1 or 65-91434-2 by reworking subkit 65C25180- 3 or 65C25180-44 to subkit 65C25180-47. (b) Inactive for procurement. Replaced by 65-91434-4. (c) Preferred Modification Top Kit. Replaces 65-91434-3. (d) Supplemental Kit. 65-91434-5 plus 65-91434-3 is equivalent to 65-91434-4. FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity Corner Reinforcement Kit -65C25180-3 (a)-...... BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 46 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 47 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity Lower Beam Reinforce- ment Kit -65C25180-4.-..... Upper Beam Reinforce- ment Kit -65C25180-42..-.... Corner Reinforcement Kit -65C25180-44 (a)...-... Corner Reinforcement Kit -65C25180-46 (b)....-.. Corner Reinforcement Kit -65C25180-47 (c).....-. Supplemental Kit, Cor- ner Reinforcement -65C25180-51 (d)......- Angle Strap-Lwr Fwd-65C25180-10 (e)1..11.. Angle Strap-Lwr Aft-65C25180-11 (f)1..11.. Angle Strap-Upr Aft-65C25180-12 (g)1..11.. Seal Retainer-65C25180-131..111. Seal Retainer-65C25180-141..111. Seal Retainer-65C25180-151..111. Seal Retainer-65C25180-161..111. Filler-65C25180-171..111. Filler-65C25180-181..111. Filler-65C25180-191..111. Filler-65C25180-201..111. Web-65C25180-25.1..... Web-65C25180-26.1..... Filler-65C25180-27.1..... Filler-65C25180-28.1..... Radius Strap-65C25180-29.1..... Radius Strap-65C25180-30.1..... Web-65C25180-33..1.... Angle-65C25180-34..1.... Filler-65C25180-35..1... Radius Strap-65C25180-36..1.... BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 47 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 48 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity Web-65C25180-38..1.... Filler-65C25180-40..1.... Radius Strap-65C25180-41..1.... Angle Strap-Upr Fwd-65C25180-43...1... Angle Strap-Upr Fwd-65C25180-45 (i)....1.. Angle Strap-Lwr Fwd-65C25180-48 (i)....... Angle Strap-Lwr Aft-65C25180-49 (i)....... Angle Strap-Upr Aft-65C25180-50 (i)....... Angle Strap-Upr Fwd65C25180-9 (j)65C25180-52 (i).....1. 65C25180-43 (j) Angle Strap-Lwr Fwd65C25180-10 (j)65C25180-53 (e) (i).....11 Angle Strap-Lwr Aft65C25180-11 (j)65C25180-54 (f) (i).....11 Angle Strap-Upr Aft65C25180-12 (j)65C25180-55 (g) (i).....11 Angle Strap-Upr Fwd-65C25180-91...... Washer-66-2955-1010..101010. Bracket-69-43929-4..1.... Bracket-69-43929-5..1.... Hi-Lok Csk 100 Deg-BACB30FM6-3101..101101101. Hi Lok-Csk 100 Deg-BACB30FN6A3113..113113113. Hi Lok-Csk 100 Deg-BACB30FN6A425..252525. Hi-Lok,Shear-BACB30FP8-6.44.... Hi-Lok,Shear-BACB30FP8-7.88.... Hi-Lok,Shear-BACB30FP8-8.88.... Hi Lok-Csk 100 Deg-BACB30FQ6A54..444. Hi-Lok Csk 100 Deg-BACB30KF6-31..111. Hi-Lok Csk 100 Deg-BACB30KF6-59..999. Hi Lok-Csk 100 Deg-BACB30KF6A518..181818. Hi-Lok Shear-BACB30KF6A6.22.... Hi Lok-Csk 100 Deg-BACB30KF6A74..444. Hi-Lok Csk 100 Deg-BACB30KK6-39..999. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 48 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 49 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity Hi-Lok Csk 100 Deg-BACB30KK6-48..888. Hi-Lok Csk 100 Deg-BACB30KK6-63..333. Bolt-Blind-BACB30VH06-02S.23..... Bolt-Blind-BACB30VH06-03S..14.... Bolt-Blind-BACB30VH06-04S.813.... Bolt-Blind-BACB30VH06-05S.214.... Bolt-Blind-BACB30VH06-06S..7.... Collar-BACC30AG8202020202020. Collar-BACC30M6243..243243243. Collar-BACC30R652..525252. Filler-Tapered-BACF3T01A11-1615..151515. Filler-Tapered-BACF3T01A11-92..222. Filler-Tapered-BACF3T01A12-91..111. Filler-Tapered-BACF3T01A13-162..222. Filler-Tapered-BACF3T01A13-82..222. Rivet-BACR15AD7D7..7.... Rivet-BACR15BB5D56.2666. Rivet-BACR15BB6D5.5332.... Rivet-BACR15BB6D6.4155.... Rivet-BACR15BB6D7.10677.... Rivet-BACR15BB6D8..4.... Rivet-BACR15BB8D8.22.... Rivet-BACR15CE3D5..30.... Rivet-BACR15CE3D7..2.... Rivet-BACR15CE5D7..2.... Rivet-BACR15CE6D4..6.... Rivet-BACR15CE6D5..4.... Rivet-Csk 100 Deg-BACR15CE6D673.20737373. Rivet-Csk 100 Deg-BACR15CE6D724.5242424. Rivet-Csk 100 Deg-BACR15CE6D8223.222. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 49 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 50 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity Rivet-BACR15CE6D9..22.... Rivet-Csk 100 Deg-BACR15DS7D62..222. Rivet-Csk 100 Deg-BACR15DS7D76..666. Rivet-Csk 100 Deg-BACR15DS7D828..282828. Rivet-BACR15ET7D10..8.... Rivet-BACR15ET7D5.15..... Rivet-BACR15ET7D6.941.... Rivet-BACR15ET7D7.49102.... Rivet-BACR15ET7D8.246.... Rivet-BACR15ET7D9.213.... Rivet-Blind-MS90354-0602.6..... Bolt-Blind (OPTIONAL BACB30VH06-02S) -0SBPT6-2 (h).23..... Bolt-Blind (OPTIONAL BACB30VH06-03S) -0SBPT6-3 (h)..14.... Bolt-Blind (OPTIONAL BACB30VH06-04S) -0SBPT6-4 (h).813.... Bolt-Blind (OPTIONAL BACB30VH06-05S) -0SBPT6-5 (h).214.... Bolt-Blind (OPTIONAL BACB30VH06-06S) -0SBPT6-6 (h)..7.... Bolt-Blind-0SB100T6-3..1.... (a) Inactive for procurement. Rework 65C25180-3 or 65C25180-44 to 65C25180-47 by replacing angle 65C25180-9 or 65C25180-43 with 65C25180-52 and by replacing angle 65C25180-10, -11 and -12 with 65C25180-53, -54 and -55, respectively. (b) Inactive for procurement. Rework 65C25180-46 to 65C25180-47 by replacing angles 65C25180-10, -11 and -12 with 65C25180-53, -54 and -55, respectively. (c) 65C25180-47 replaces 65C25180-46. (d) 65C25180-51 plus 65C25180-46 is equivalent to 65C25180-47. (e) 65C25180-10 is replaced by 65C25180-53. (f) 65C25180-11 is replaced by 65C25180-54. (g) 65C25180-12 is replaced by 65C25180-55. (h) Huck Manufacturing Company (V17446), 900 Watson Center Road, Carson, CA 90745. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 50 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 51 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -3-4-42-44-46-47-51 NameExisting Part Number New Part NumberQuantity (i) 65C25180-45 is superseded by 65C25180-52, 65C25180-48 is superseded by 65C25180-53, 65C25180- 49 is superseded by 65C25180-54, 65C25180-50 is superseded by 65C25180-55. (j) You can use the existing part to replace the new or changed part. If you use the existing part, you cancel the effect of the change given in this service bulletin. FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -5-6-7-8 NamePart NumberQuantity Subkit, Frame Instl-Lwr Fwd65C25180-5 (a)-... Subkit, Frame Instl-Lwr Aft65C25180-6 (a).-.. Subkit, Frame Instl-Lwr Fwd65C25180-7 (b)..-. Subkit, Frame Instl-Lwr Aft65C25180-8 (b)...- Frame-Lwr Fwd65C25180-211... Frame-Lwr Fwd65C25180-22..1. Frame-Lwr Aft65C25180-23.1.. Frame-Lwr Aft65C25180-24...1 WasherAN960-4163333 WasherAN960PD10L4.4. WasherAN960PD416L2222 Hi-LokBACB30FP6-33333 Hi-LokBACB30FP6-46666 BoltBACB30LK3-4X1.1. Bolt-Csk 100 DegBACB30LU3-5X1.1. Bolt-BlindBACB30VH06-04S6868 Bolt-BlindBACB30VH06-05S4343 Bolt-BlindBACB30VH06-06S.2.2 Bolt-BlindBACB30VH06-07S.4.4 CollarBACC30AG69999 Nut PlateBACN10JR3F7575 NutplateBACN10KB3F2.2. RivetBACR15BB5D55151 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 51 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 52 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)65C25180 -5-6-7-8 NamePart NumberQuantity RivetBACR15BB6D64444 Rivet-Csk 100 DegBACR15CE6D64444 Rivet-Csk 100 DegBACR15DS7D68.8. Rivet-Csk 100 DegBACR15DS7D77878 RivetBACR15ET7D104444 RivetBACR15ET7D68686 RivetBACR15ET7D7923923 RivetBACR15ET7D8812812 RivetBACR15ET7D93232 ShimBACS40R06C301111 NutMS21042L32.2. NutMS21042L45555 ScrewNAS623-3-42.2. BoltNAS6604-10X2222 BoltNAS6604-4X3333 Bolt-Blind (OPTIONAL BACB30VH06-04S)0SBPT6-4 (c)6868 Bolt-Blind (OPTIONAL BACB30VH06-05S)0SBPT6-5 (c)4343 Bolt-Blind (OPTIONAL BACB30VH06-06S)0SBPT6-6 (c).2.2 Bolt-Blind (OPTIONAL BACB30VH06-07S)0SBPT6-7 (c).4.4 (a) Applicable for Group 1 airplanes. (b) Applicable for Group 2 airplanes. (c) Huck Manufacturing Company (V17446), 900 Watson Center Road, Carson, CA 90745. 2. Parts and Materials Supplied by the Operator: INSPECTION AND MODIFICATION SUPPLIES NameSpecificationQuantity SealantBMS 5-95, Class BAs Required Leveling CompoundBMS 5-125, Type 1 (a)As Required Bonding CompoundBMS 5-92, Type 3As Required (a) Epibond 1542 A/B, M&T Chemicals (V99384), Furane Products Division, 5121 San Fernando Road West, Los Angeles, CA 90039. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 52 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 53 REPAIR PARTS - LOWER BEAM FORWARD END (FIG 4) NameSpecificationQuantity Filler A0.056 x 1.9 x 10.9, clad 7075-T6 or 2024-T31 Radius Filler AMake from BAC1512-3355 x 0.65 wide x 11.0 long, 7075- T6511 or 2024-T3511 1 Radius Filler BMake from BAC1512-3355 x 0.60 wide x 6.5 long, 7075- T6511 or 2024-T3511 1 Radius Filler CMake from BAC1512-3355 x 0.65 wide x 0.90 long, 7075- T6511 or 2024-T3511 2 Angle A1.55 x 8.30 x 0.040, 2024-01 Angle B1.44 x 6.40 x 0.050, 2024-01 Replacement 'T' Chord ABAC1505-100570 x 8.0, 2024-0 (a)1 Doubler4.83 x 11.67 x 0.071, 7075-01 RivetBACR15BB7D98 RivetMS20470D6-7. Optional: BACR15BB6D72 RivetBACR15CE6D6. Optional: BACR15GF6D62 RivetBACR15CE6D8. Optional: BACR15GF6D813 RivetBACR15CE6D9. Optional: BACR15GF6D97 Chemical Film Treatment(Alodine 1200S) MIL-C-5541As Required PrimerBMS 10-11, Type 1As Required (a) As an option to joggling the 2024-0 extrusion and heat-treating in accordance with Figure 4, replacement 'T' chord A can be made from part 65C80735-25 by trimming part to length. REPAIR PARTS - LOWER BEAM AFT END (FIG 6) (a) NameSpecificationQuantity Radius Filler BMake from BAC1512-3355 x 0.60 wide x 6.50 long, 7075- T6511 or 2024-T3511 1 Radius Filler CMake from BAC1512-3355 x 0.65 wide x 0.90 long, 7075- T6511 or 2024-T3511 2 Angle C1.55 x 8.50 x 0.040, 2024-01 Angle D1.44 x 6.50 x 0.050, 2024-01 Replacement 'T' Chord BBAC1505-100570 x 9.0, 2024-0 (b)1 RivetBACR15BB7D98 RivetBACR15CE6D6. Optional: BACR15GF6D63 RivetBACR15CE6D8. Optional: BACR15GF6D82 RivetBACR15CE6D9. Optional: BACR15GF6D97 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 53 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 54 REPAIR PARTS - LOWER BEAM AFT END (FIG 6) (a) NameSpecificationQuantity Chemical Film Treatment(Alodine 1200S) MIL-C-5541As Required PrimerBMS 10-11, Type 1As Required (a) In addition to the parts shown below, you will need doubler 65C25180-25, filler 65C25180-27, and radius strap 65C25180-30. These parts are contained in subkit 65C25180-4. (b) As an option to joggling the 2024-0 extrusion and heat-treating in accordance with Figure 6, replacement 'T' chord B can be made from part 65C80735-25 by trimming part to length. 3. Parts Modified and Reidentified: The parts shown below are changed in accordance with this service bulletin. The quantity (QTY) is the number of parts changed on each airplane. NotesNew Part NumberNameQTYExisting Part Number (a) (b) (c)-Door Assembly165-47952-1 (a) (b) (c)-Door Assembly165-47952-524 (a) Make the change in accordance with this service bulletin. (b) There is no equivalent Boeing part number for the changed part. Identify on the part that the change in accordance with this service bulletin was made. (c) You can use the existing part to replace the new or changed part. If you use the existing part, you cancel the effect of the change given in this service bulletin. 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. NamePart NumberQuantity Modification Top Kit65-91434-41 E. Special Tooling - Price and Availability The operator can supply the tools shown in Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin. Tool price and supply data are not given. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 54 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 55 F. Special Tooling Necessary to do this Service Bulletin To get the tools shown below, refer to Paragraph 2.E., Special Tooling - Price and Availability. Maintenance and overhaul tools in the manuals shown in Paragraph 1.J., References, can also be necessary. Examine operator tool supply to make sure all necessary tools are available. NotesNameTool Kit Number (a) (c)TransducerSUS 1015-10MHz-70A (b) (c)TransducerHS-7520-10-70A (a) Available from: NDT Engineering Corporation (Cage Code 61100) 19620 Russell Road Kent, WA 98032-1115 (b) Available from: Staveley Sensors Inc. (Cage Code 59334) 91 Prestige Park Circle East Hartford, CT 06108-1918 (c) A different vendor can make the transducer. But it must have the properties specified below, that the transducer: - Puts a shear wave in aluminum that is between 65 and 75 degrees. - Operates at a frequency of between 9 MHz and 11 MHz. - Has a maximum outer case length of 0.315 inches (8.0 mm). - Can give satisfactory results during calibration as specified in 737 NDT Manual, Part 4, 52-10-02. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 55 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 56 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 56 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT BLANK PAGE ### Page 57 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: — Linear dimensions are in inches — Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch — Angular tolerance is plus or minus 2 degrees — For hole dimensions for standard solid rivets, refer to 737 Structural Repair Manual, Chapter 51 — For torque limits to tighten nuts and bolts, refer to 737 Structural Repair Manual, Chapter 51. — Shim all gaps greater than 0.005 inch. 4. For approved fastener and process material substitutions, refer to 737 Structural Repair Manual, Chapter 51. For alternate fasteners, refer to 737 Structural Repair Manual Chapter 51. 5. If the length of fasteners specified in this service bulletin do not meet the installation standards, fasteners of the same specification, or an approved substitute, one grip length longer or shorter may be used. 6. As recommended by the 737 Aging Fleet Structures Working Group, accomplish the modification in accordance with this service bulletin, Part II, prior to, or upon the accumulation of 75,000 flight cycles as required by AD 90-06-02. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 57 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 58 7. 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. 8. 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 ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal 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. 9. These work instructions refer to procedures included on 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. B. WORK INSTRUCTIONS GROUP 1 AND 2 AIRPLANES 1. PART I - Access NOTE: If you previously installed reinforcement angles 65C25180-9 or -43 (upper forward), -10 (lower forward), -11 (lower aft) or -12 (upper aft), in accordance with the original issue, Revision 1, 2, 3, or 4 of this service bulletin, then do Part V - 'Corner Inspection and Rework'. 1. 2. The following instructions supplement information contained on Drawing 65C25180. Unless otherwise noted all references herein are to that drawing. a. Remove or push aside the insulation in the aft cargo door as required to gain access to the inside of the four corner frames and the ends of the upper and lower cross beams. b. Identify the aft cargo door assembly part number which is currently installed on each airplane in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is found to be from an airplane in the line number greater than 873, accomplish all applicable actions in accordance with the original issue of Boeing Service Bulletin 737-52A1153 . c. Remove the aft cargo door. Refer to 737-100/200 AMM 52-31-0 as an accepted procedure. d. Remove the aft cargo door flap type seal. Refer to 737-100/200 AMM 52-09-121 as an accepted procedure. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 58 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 59 e. Remove and discard corner seal retainers in accordance with Sheet 2, Views 1A5-1 and 1A7-1 and Sheet 3, Views 3B5 and 3C11. Remove and retain the forward and aft seal retainers in accordance with Sheet 2, Views 1A5-1 and 1A7-1. f. Remove exterior skin fasteners in accordance with Sheet 1, View 3A2. NOTE: Remove any sealant found in each frame corner radius before inspection. If cracks do exist in this inspection area they could be hidden under the existing sealant. g. Do Part II - Inspection. 2. PART II - Inspection a. Remove or push aside the insulation in the aft cargo door as required to gain access to the inside of the four corner frames and the ends of the upper and lower cross beams. b. Identify the aft cargo door assembly part number which is currently installed on each airplane in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is found to be from an airplane in the line number greater than 873, accomplish all applicable actions in accordance with Service Bulletin 737-52A1153 , Original Issue. c. Do the inspection in accordance with FIGURE 1. d. If no cracks are found, modify the door in accordance with Part III. e. If cracks up to complete severance are found in the upper or lower beam web, repair the beam in accordance with the beam modification in Part III. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . f. For the lower beam, if cracks are found in the web and outer "T" chord or in the outer "T" chord only, then repair the beam in accordance with Part VI - Lower Beam Outer "T" Chord Repair. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . g. For the upper beam, if cracks are found in the outer "T" chord, contact Boeing for repair instructions and do the repair before further flight. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 59 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT ### Page 60 h. If cracks are found in the forward or aft upper corner frame, replace the frame and install the preventive modification in accordance with Part III. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . i. If cracks are found in the forward or aft lower door frame, replace the damaged frame in accordance with Part IV Lower Forward and Aft Frame Replacement and modify in accordance with Part III - Preventive Modification. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . j. Put the airplane back to a serviceable condition. 3. PART III - Preventive Modification NOTE: The following instructions supplement information contained on Drawing 65C25180. Unless otherwise noted all references herein are to that drawing. a. Gain access to the lower beam by removing the door inner skin in accordance with Sheet 1, View 1A2. Retain removed parts for reinstallation. b. Gain access to the upper beam by removing the door inner skin in accordance with Sheet 5, View 4A2-1. Retain removed parts for reinstallation. c. If cracks are found during inspection of the lower and upper cross beams, trim out the web cracks with a 0.40 minimum trim radius. Do a HFEC surface inspection within 0.20 of the edge of the trim out. If cracks are found, trim them out and repeat the HFEC surface inspection. When no cracks are found, make a 0.20 insurance cut to the edge of the trim out. Maintain 0.38 minimum edge margins. Replace trim out with a 7075-T6 aluminum filler. Finish filler with one coat of chemical conversion coating (Alodine 1200S, Type II), refer to SOPM 20-43-03 and one coat of primer (BMS 10-11, Type I), refer to SOPM 20-41-02 . Do the Preventive Modification to the upper and lower cross beams in accordance with paragraphs d and e. In addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance . d. Use Kit 65C25180-4 and modify the lower cross beam in accordance with Sheet 2, Views B1-1 and B3-1. e. Use Kit 65C25180-42 and modify the upper cross beam in accordance with Sheets 5 and 6. f. Use Kit 65C25180-47 and locate and drill corner reinforcement angles and seal retainers in accordance with Sheet 1, View 3A2; Sheet 2, Views 1A5-1 and 1A7-1; and Sheet 3, Views 3B5 and 3C11. NOTE: Trim corner strap angles on installation as required to fit door stops, latch torque tube housing and water drain seal retainer in accordance with Sheet 2, View 1A5-1 and 1A7-1. g. Remove seal retainers and trim ends in accordance with Sheet 1, View C8. Apply chemical film treatment (Alodine or Iridite, Refer to 737-100/200 SRM 51-10-2 as an accepted procedure) and one coat of epoxy primer (Ref. BMS 10-11, Type 1). BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 16, 1983 737-52A1079Revision 7: December 17, 2010 60 of 103 BOEING SERVICE BULLETIN 737-52A1079 ALERTALERT The text continues at https://openairdocs.org/service-documents/boeing/737-52a1079/file/c272ecc3dcf8.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.