# Boeing Alert Service Bulletin 737-55A1033: Revision 2 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2016-7426; AD 2017-11-01 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-55A1033](https://openairdocs.org/service-documents/boeing/737-55a1033.md) - Title as filed: SB-737-55A1033R2 - Pages: 103 - PDF: https://openairdocs.org/files/sha256/80/ea/80ea7f0858e7a124dc1a3aa0bc6c683e633a62ef4f8a84eb9ff70474b2c434e8 - Page: https://openairdocs.org/service-documents/boeing/737-55a1033/file/80ea7f0858e7 ## 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: 737-55A1033 Original Issue: April 12, 1985 Revision 2: August 07, 2015 ATA System: 5510 SUBJECT: STABILIZERS - Horizontal Stabilizer - Joint Inspection Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 1989 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 1 of 103 5.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 2 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 43 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 45 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 46 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 FIGURE 1: CENTER SECTION REAR SPAR UPPER CLEVIS LUGS DETAILED, HFEC, AND ULTRASONIC INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 FIGURE 2: HORIZONTAL STABILIZER REAR SPAR UPPER LUGS DETAILED, HFEC, AND ULTRASONIC INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 FIGURE 3: CENTER SECTION REAR SPAR UPPER CLEVIS LUGS HFEC AND DYE PENETRANT INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 FIGURE 4: HORIZONTAL STABILIZER REAR SPAR UPPER LUG HFEC AND DYE PENETRANT INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 FIGURE 5: CENTER SECTION FRONT AND REAR SPAR UPPER CLEVIS LUGS HFEC AND DYE PENETRANT INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 3 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 4 FIGURE 6: HORIZONTAL STABILIZER FRONT AND REAR SPAR UPPER LUG HFEC AND DYE PENETRANT INSPECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 FIGURE 7: LUG PREPARATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 FIGURE 8: BUSHING INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 APPENDIX A: DEFINITION FOR 0.780 INCH AND 0.932 INCH THICK REAR SPAR UPPER LUGS . . . 84 APPENDIX B: BUSHING AND SLEEVE MATERIAL AND FABRICATION . . . . . . . . . . . . . . . . . 87 APPENDIX C: HORIZONTAL STABILIZER INSTALLATION BOLT CONFIGURATIONS . . . . . . . . . 91 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 4 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 5 Commercial Airplanes 737 Service Bulletin ALERT Revision Transmittal SheetNumber: 737-55A1033Original Issue: April 12, 1985 Revision 2: August 07, 2015 ATA System: 5510 SUBJECT: STABILIZERS - Horizontal Stabilizer - Joint Inspection This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION This service bulletin is related to Federal Aviation Administration Airworthiness Directives FAA AD 86-12-05 and FAA AD 84-23-05. FAA AD 84-23-05 superseded FAA AD 81-11-07. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. The airplanes from Boeing Service Bulletin (SB) 737-55A1029 have been added to the effectivity of this service bulletin as Group 1 airplanes. More work is necessary on airplanes that have accomplished the inspections or modifications in accordance with Revision 1 or the Original Issue of this service bulletin or Revision 1, Revision 2, Revision 3, Revision 4, or Original Revision of service bulletin 737-55A1029. Refer to Paragraph 1.E., Compliance for new compliance times. REASON FOR REVISION This revision is sent to provide new inspection and new compliance information and repair information. This revision is also sent to change the service bulletin to Alert Status and to modify the inspection threshold information based on service related experience. This revision also replaces Boeing Service Bulletin 737-55A1029. Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. Because this bulletin incorporates requirements from SB 737-55A1029 in addition to multiple formating changes, this constitutes a complete rewrite of this service bulletin. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. REVISION HISTORY April 12, 1985Original Issue: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 5 of 103 ### Page 6 November 30, 1989Revision 1: August 07, 2015Revision 2: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 6 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 7 Commercial Airplanes 737 Service Bulletin ALERT SummaryNumber: 737-55A1033Original Issue: April 12, 1985 Revision 2: August 07, 2015 ATA System: 5510 SUBJECT: STABILIZERS - Horizontal Stabilizer - Joint Inspection 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 During accomplishment of Service Bulletin 737-55-1026 on a Group 2 airplane with 28,704 flights, an operator detected a cracked center section rear spar upper chord clevis lug. The crack was in the forward face of the aft lug of the clevis, extending from the lug hole at the 12 o'clock position. The chord was replaced. Subsequent analysis of the cracked lug indicated fatigue was the cause of cracking. Four operators of Group 2 airplanes have also reported one airplane with cracked shim and eight airplanes with corrosion. These airplanes had between 17,160 and 42,050 flight cycles. Failure to detect cracks in the horizontal stabilizer center section rear spar clevis lugs prior to their reaching critical length may result in unscheduled spar chord replacement or loss of the horizontal stabilizer and elevator, resulting in loss of controllability of the airplane.. Group 1 airplanes were originally in Service Bulletin 737-55A1029. Revision 2 of this service bulletin replaces Service Bulletin 737-55A1029. All airplanes originally in Service Bulletin 737-55A1029 are now in Group 1 of this service bulletin. Subsequent to the release of Revision 4 of Service Bulletin 737-55A1029, four operators of Group 1 airplanes found six airplanes with cracks in the clevis lugs while completing inspections in accordance with Service Bulletin 737-55A1029 R04. The airplanes had between 41,900 and 69,200 flight cycles. Group 2 airplanes have thicker horizontal stabilizer center section rear spar upper chord attach lugs than earlier airplanes affected by Service Bulletin 737-55A1029, which reported cracked lugs. Subsequent to the original release of this service bulletin, two operators of Group 2 airplanes found three airplanes with cracked clevis lugs. The airplanes had between 41,900 and 69,200 flight cycles. The cracking was very similar to fatigue cracking on early airplanes reported in Service Bulletin 737-55A1029. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 7 of 103 ### Page 8 A structural reassessment of the 737 airplane has been conducted under the requirements of the FAA Advisory Circular 91-56 in accordance with Federal Aviation Regulation (FAR) 25.571, as amended in 1978, to ensure safe operation of 737 airplanes throughout their operational life. As a result of this reassessment, the structure affected by this service bulletin has been determined to be structurally significant in that it is critical to the structural integrity of the airplane and should be inspected in accordance with a Flight Safety Inspection Program. The integrity of the horizontal stabilizer rear spar terminal fittings, which comprise of the center section clevis lugs and the outboard section lugs, is dependent on the integrity of the front spar terminal fittings. Therefore, a flight safety inspection program describing inspections necessary to maintain the structural integrity of the airplane must include the front and rear spar terminal fittings and are defined in this service bulletin. 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. Boeing Fleet Team Digest (FTD) 737 FTD 55-02001 is related to this service bulletin. ACTION Get access to the horizontal stabilizers and center section rear spar upper lugs. At the times specified in Paragraph 1.E., Compliance, do PART 2 Detailed and High Frequency Eddy Current (HFEC) and Ultrasonic inspections of the horizontal stabilizer and center section lugs to detect any crack indication. Based on inspection findings do PART 2 repeat inspections or PART 3 to confirm crack indication. Based on inspection findings in PART 3, do PART 2 repeat inspections or PART 3A inspection and subsequent corrective actions. EFFECTIVITY 737-100/-200/-200C airplanes. See Paragraph 1.A.1., Airplane(s), for effectivity. COMPLIANCE Refer to Paragraph 1.E., Compliance. FAA AD 86-12-05 and FAA AD 84-23-05 are related to this service bulletin. FAA AD 84-23-05 superseded FAA AD 81-11-07. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspections given in this service bulletin. MANPOWER Refer to Paragraph 1.G., Manpower. MATERIAL INFORMATION Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 8 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 9 (OCR) BOEING SERVICE BULLETIN 737-55A1033 ALERT ALERT SCHEDULED INSPECTION FOR CRACKS ON HORIZONTAL STABILIZER FRONT SPAR JOINTS INSPECT FOR CRACKS ON HORIZONTAL STABILIZER UPPER REAR SPAR JOINTS AND SCHEDULED INSPECTION FOR CRACKS ON HORIZONTAL STABILIZER REAR SPAR JOINTS. 2350416 Original Issue: April 12, 1985 Revision 2: August 07, 2015 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-55A1033 Work - See page 1 for details. 9 of 103 ### Page 10 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 10 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT BLANK PAGE ### Page 11 Commercial Airplanes 737 Service Bulletin ALERT Number: 737-55A1033 Original Issue: April 12, 1985 Revision 2: August 07, 2015 ATA System: 5510 SUBJECT: STABILIZERS - Horizontal Stabilizer - Joint Inspection 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 Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. An equivalent change is on subsequent production airplanes. Refer to PRR 31913 for data about this change. DESCRIPTIONCONFIGURATIONGROUP 737-100/200/200C Airplanes. Line numbers 1 through 315, 323 and 324. Airplanes with 0.780 inch thick horizontal stabilizer center section rear spar upper chord clevis lugs installed in production. -1 Airplanes with 0.780 inch thick horizontal stabilizer center section rear spar upper chord clevis lugs as of the release date of Revision 2 of this service bulletin. 1 Airplanes that have 0.932 inch thick horizontal stabilizer center section rear spar upper chord clevis lugs as of the release date of Revision 2 of this service bulletin. 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 11 of 103 ### Page 12 DESCRIPTIONCONFIGURATIONGROUP 737-200/200C Airplanes. Line numbers 316 through 322 and Line Number 325 and on. These airplanes have 0.932 inch thick horizontal stabilizer center section rear spar upper chord clevis lugs installed in production. -2 Airplane Models: 737-100, 737-200, 737-200C GroupVariable Number 1PA001 - PA022 1PA099 1PA231 - PA232 1PC001 - PC005 1PG001 - PG075 1PG199 1PG201 - PG230 1PG251 - PG255 1PG271 - PG279 1PG301 - PG314 1PG331 - PG332 1PG351 - PG356 1PG375 1PG401 - PG403 1PG431 - PG442 1PG471 - PG475 1PG501 - PG505 1PG571 - PG586 1PG621 - PG630 1PG651 - PG652 1PG701 - PG705 1PH001 1PH011 2PH012 - PH013 2PH021 - PH024 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 12 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 13 GroupVariable Number 1PH701 - PH715 1PH731 - PH732 1PH741 - PH742 2PH743 1PJ001 - PJ002 2PJ003 - PJ009 1PJ031 - PJ032 1PJ071 - PJ072 1PJ101 - PJ104 2PJ105 - PJ119 2PJ201 - PJ219 2PK026 - PK029 2PK041 - PK053 2PK061 - PK070 2PK081 - PK082 2PK091 - PK099 2PK101 - PK103 2PK111 - PK120 2PK141 - PK146 2PK201 - PK204 2PK211 - PK223 2PK231 - PK241 2PK251 - PK258 2PK271 - PK274 2PK281 - PK289 2PK291 2PK301 - PK318 2PK341 2PK351 - PK361 2PK391 2PK431 - PK433 2PK451 - PK452 2PK461 - PK469 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 13 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 14 GroupVariable Number 2PK495 2PK501 - PK504 2PK511 - PK515 2PK519 2PK521 - PK528 2PK541 - PK565 2PK581 2PK591 - PK599 2PK601 - PK617 2PK621 - PK637 2PK641 - PK642 2PK661 - PK666 2PK671 - PK681 2PK691 - PK697 2PK711 - PK716 2PK731 - PK765 2PK771 - PK779 2PK801 - PK804 2PK819 - PK827 2PK830 2PK861 - PK863 2PK871 - PK874 2PK881 - PK884 2PK901 - PK938 2PK971 - PK974 2PL001 - PL028 2PL061 2PL081 2PL101 - PL113 2PL151 2PL171 - PL172 2PL201 - PL203 2PL221 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 14 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 15 GroupVariable Number 2PL401 - PL417 2PL421 2PL441 2PL451 - PL456 2PL471 2PL491 2PL501 - PL506 2PL551 - PL562 2PL581 2PL601 - PL603 2PL611 2PL621 - PL626 2PL631 - PL632 1PL711 - PL712 1PL716 2PL717 - PL725 1PL726 - PL728 2PL729 - PL735 1PL736 - PL742 2PL743 - PL747 1PL756 2PL758 1PL761 - PL762 2PL763 - PL770 1PL781 - PL782 2PL783 - PL788 1PL793 1PL801 - PL803 2PM001 - PM006 2PM016 - PM017 2PM021 - PM023 2PM051 - PM066 2PM101 - PM119 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 15 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 16 GroupVariable Number 2PM141 - PM142 2PM171 2PM181 2PM251 - PM255 2PM281 - PM283 2PN001 - PN002 2PN021 - PN043 2PN081 - PN086 2PN101 - PN117 2PN131 - PN163 2PN401 - PN420 2PN431 - PN433 2PN451 - PN456 2PN471 - PN474 2PN481 2PN491 - PN493 2PN501 - PN502 2PN511 - PN512 2PN521 1PX071 1PX701 1PY001 - PY008 1PY021 2PY022 1PY031 1PY036 - PY037 1PY046 - PY047 2PY048 1PY051 2PY052 - PY053 2PY056 - PY057 2PY101 - PY103 2PY111 - PY113 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 16 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 17 GroupVariable Number 2PY131 - PY135 2PY141 - PY143 2PY151 - PY154 2PY156 - PY157 2PY161 - PY162 2PY166 2PY191 2PY201 2PY221 - PY222 2PY231 2PY241 - PY244 2PY270 - PY275 2PY281 2PY286 1PY301 - PY304 1PY321 - PY323 1PY341 - PY346 1PY361 - PY362 1PY381 2PY401 2PY409 - PY411 2PY421 - PY422 2PY441 2PY451 2PY461 - PY463 2PY591 - PY595 2PY611 - PY612 2PY621 2PY631 2PY651 2PY671 - PY672 2PY721 2PY741 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 17 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 18 2. Spares Affected None. B. Concurrent Requirements None. C. Reason During accomplishment of Service Bulletin 737-55-1026 on a Group 2 airplane with 28,704 flights, an operator detected a cracked center section rear spar upper chord clevis lug. The crack was in the forward face of the aft lug of the clevis, extending from the lug hole at the 12 o'clock position. The chord was replaced. Subsequent analysis of the cracked lug indicated fatigue was the cause of cracking. Four operators of Group 2 airplanes have also reported one airplane with cracked shim and eight airplanes with corrosion. These airplanes had between 17,160 and 42,050 flight cycles. Failure to detect cracks in the horizontal stabilizer center section rear spar clevis lugs prior to their reaching critical length may result in unscheduled spar chord replacement or loss of the horizontal stabilizer and elevator, resulting in loss of controllability of the airplane. Group 1 airplanes were originally in Service Bulletin 737-55A1029. Revision 2 of this service bulletin replaces Service Bulletin 737-55A1029. All airplanes originally in Service Bulletin 737-55A1029 are now in Group 1 of this service bulletin. Subsequent to the release of Revision 4 of Service Bulletin 737-55A1029, four operators of Group 1 airplanes found six airplanes with cracks in the clevis lugs while completing inspections in accordance with Service Bulletin 737-55A1029 R04. The airplanes had between 41,900 and 69,200 flight cycles. Group 2 airplanes have thicker horizontal stabilizer center section rear spar upper chord attach lugs than earlier airplanes affected by Service Bulletin 737-55A1029, which reported cracked lugs. Subsequent to the original release of this service bulletin, two operators of Group 2 airplanes found three airplanes with cracked clevis lugs. The airplanes had between 41,900 and 69,200 flight cycles. The cracking was very similar to fatigue cracking on early airplanes reported in Service Bulletin 737-55A1029. A structural reassessment of the 737 airplane has been conducted under the requirements of the FAA Advisory Circular 91-56 in accordance with Federal Aviation Regulation (FAR) 25.571, as amended in 1978, to ensure safe operation of 737 airplanes throughout their operational life. As a result of this reassessment, the structure affected by this service bulletin has been determined to be structurally significant in that it is critical to the structural integrity of the airplane and should be inspected in accordance with a Flight Safety Inspection Program. The integrity of the horizontal stabilizer rear spar terminal fittings, which comprise of the center section clevis lugs and the outboard section lugs, is dependent on the integrity of the front spar terminal fittings. Therefore, a flight safety inspection program describing inspections necessary to maintain the structural integrity of the airplane must include the front and rear spar terminal fittings and are defined in this service bulletin. 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. Revision 1 was issued to provide the recommendations of the Aging Fleet Structures Working Group. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 18 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 19 Revision 2 is sent to provide new compliance information and add new inspection and repair information. Revision 2 is also sent to change the service bulletin to Alert Status and to modify the inspection threshold information based on service related experience. Optional work instructions are also added which allow operators the possibility of reworking a damaged lug instead of replacing the rear spar upper chord. Revision 2 is also sent to replace service bulletin 737-55A1029. Boeing Fleet Team Digest (FTD) 737 FTD 55-02001 is related to this service bulletin. D. Description Get access to the horizontal stabilizers and center section rear spar upper lugs. At the times specified in Paragraph 1.E., Compliance, do PART 2 Detailed and High Frequency Eddy Current (HFEC) and Ultrasonic inspections of the horizontal stabilizer and center section lugs to detect any crack indication. Based on inspection findings do PART 2 repeat inspections or PART 3 to confirm crack indication. Based on inspection findings in PART 3, do PART 2 repeat inspections or PART 3A inspection and subsequent corrective actions. Revision 1 - Airplanes modified per the previous release of this service bulletin require additional work per Service Bulletin 737-55-1028, Revision 2, 3, or 4, Part I for the outboard rear spar upper chord attach lug on the commonly affected airplanes. On airplanes not commonly affected by this service bulletin and Service Bulletin 737-55-1028, modify per 737 Maintenance Manual Subject 27-41-131. Revision 2 - More work is necessary on airplanes that have accomplished the inspections or modifications in accordance with Revision 1 or the original issue of this service bulletin. More work is necessary on airplanes that have accomplished the inspections or modifications in accordance with Revision 1, 2, 3, 4 or the original issue of Service Bulletin 737-55A1029. Refer to Paragraph 1.E., Compliance for new compliance times. The work in this service bulletin is done in the maintenance zone(s) given below. Group 1: Affected Maintenance Zones ZoneModel 7-9, 7-10737-100, 737-200, 737-200C Group 2: Affected Maintenance Zones ZoneModel 7-9, 7-10737-200, 737-200C E. Compliance Federal Aviation Administration (FAA) Airworthiness Directives (AD) AD 86-12-05 and FAA AD 84-23-05 are related to this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 19 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 20 The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Do the required actions in accordance with Paragraph 3. Accomplishment Instructions. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. The table that follows immediately below describes the service bulletin PARTS noted in the compliance tables. Completing PART 3A inspections fulfills PART 7 and PART 7A inspections. DescriptionTitle ACCESSPART 1 CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPEC- TIONS PART 2 HORIZONTAL STABILIZER REAR UPPER LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS PART 2A CENTER SECTION AND HORIZONTAL STABILIZER REAR SPAR UPPER CHORD CONDITIONAL TEAR- DOWN INSPECTION PART 3 CENTER SECTION AND HORIZONTAL STABILIZER FRONT AND REAR SPAR UPPER CHORD LUG CONDITIONAL TEARDOWN INSPECTION PART 3A LUG REPAIRPART 4 LUG REPAIR - BORE OVERSIZEPART 5 INSTALLATIONPART 6 CENTER SECTION SCHEDULED TEARDOWN IN- SPECTION PART 7 HORIZONTAL STABILIZER SCHEDULED TEAR- DOWN INSPECTION PART 7A NEW CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT PART 8 SERVICEABLE CENTER SECTION REPLACEMENTPART 9 SERVICEABLE HORIZONTAL STABILIZER REPLACE- MENT PART 10 CLOSE ACCESSPART 11 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 20 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 21 Group 1, Configuration 1: Table 1: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 1,500 Horizontal Stabilizer Center Section flight cycles or 12 months, whichever occurs first, af- ter the Revision 2 date of this service bulletin. Do PART 2 for any crack.All airplanes -Within 6,000 Horizontal Stabilizer Center Section flight cycles or 5 years, whichever occurs first, af- ter the Revision 2 date of this service bulletin. OPTION 1: Do PART 8. (a)All airplanes -OPTION 2: Do PART 9. (a) (b) 1,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 1: NO CRACK FOUND during PART 2 -Before further flight.Do PART 3 for any crack.CONDITION 2: ANY CRACK FOUND during PART 2 1,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 5: NO CRACK FOUND during PART 3 -Before further flight.Do PART 3A for any crack.CONDITION 6: ANY CRACK FOUND during PART 3 -Before further flight.OPTION 1: Do PART 4.CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A -OPTION 2: Do PART 8. (a) -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A -OPTION 2: Do PART 8. (a) -OPTION 3: Do PART 9. (a) (b) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 21 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 22 Group 1, Configuration 1: Table 1: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.OPTION 1: Do PART 4.CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 4.CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE CHAM- FER OR LUG FACE dur- ing PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (c) -OPTION 3: Do PART 10. (b) (c) -Before further flight.OPTION 1: Do PART 5.CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (c) -OPTION 3: Do PART 10. (b) (c) (a) For the denoted action, refer to Table 2 for post replacement center section inspections. (b) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (c) If the denoted action results in the horizontal stabilizer rear spar upper chord being replaced, or it results in the entire horizontal stabilizer being replaced, then hereafter, refer to Table 6 for post replacement horizontal stabilizer inspections. (d) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 22 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 23 Group 1, Configuration 1: Table 2: POST NEW OR SERVICEABLE CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 18,000 Horizontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first, af- ter replacement. Do PART 2 for any crack. (d) All airplanes with New 0.932 Inch Thick Center Section Rear Spar Upper Chord (c) -Within 4,500 Horizontal Stabilizer Center Section flight cycles after replace- ment. All airplanes with Service- able 0.932 Inch Thick Center Section Rear Spar Upper Chord (c) 4,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 1: NO CRACK FOUND during PART 2 -Before further flight.Do PART 3 for any crack.CONDITION 2: ANY CRACK FOUND during PART 2 4,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 5: NO CRACK FOUND during PART 3 -Before further flight.Do PART 3A for any crack.CONDITION 6: ANY CRACK FOUND during PART 3 -Before further flight.OPTION 1: Do PART 4.CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 5.CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 4.CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 23 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 24 Group 1, Configuration 1: Table 2: POST NEW OR SERVICEABLE CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.OPTION 1: Do PART 5.CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 4.CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE CHAM- FER OR LUG FACE dur- ing PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (b) -OPTION 3: Do PART 10. (a) (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (b) -OPTION 3: Do PART 10. (a) (b) (a) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (b) If the denoted action results in the horizontal stabilizer rear spar upper chord being replaced, or it results in the entire horizontal stabilizer being replaced, then hereafter, refer to Table 6 for post replacement horizontal stabilizer inspections. (c) Tables 1, 5, 6, and 7 are lead in for the post replacement requirements. (d) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 24 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 25 Group 1, Configuration 2; Group 2: Table 3: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC CONDITIONAL INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Within 3,000 Horizon- tal Stabilizer Center Section flight cycles or 12 months, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Do PART 2 for any cracks. All airplanes with original or service- able center section rear spar upper chord -Within 3,000 Horizon- tal Stabilizer Center Section flight cycles or 12 months, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Within 18,000 Hori- zontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first, after replace- ment. All airplanes that have new center section rear spar up- per chord 3,000 Horizontal Sta- bilizer Center Section flight cycles if PART 7 has NOT been ac- complished. --Repeat PART 2 for any crack. (d) CONDITION 1: NO CRACK FOUND dur- ing PART 2 4,500 Horizontal Sta- bilizer Center Section flight cycles if PART 7 has been accom- plished. --Before further flight.Do PART 3 for any crack. CONDITION 2: ANY CRACK FOUND dur- ing PART 2 3,000 Horizontal Sta- bilizer Center Section flight cycles if PART 7 has NOT been ac- complished. --Repeat PART 2 for any crack. (d) CONDITION 5: NO CRACK FOUND dur- ing PART 3 4,500 Horizontal Sta- bilizer Center Section flight cycles if PART 7 has been accom- plished. --Before further flight.Do PART 3A for any crack. CONDITION 6: ANY CRACK FOUND dur- ing PART 3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 25 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 26 Group 1, Configuration 2; Group 2: Table 3: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC CONDITIONAL INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Before further flight.OPTION 1: Do PART 4. CONDITION 7: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE CHAM- FER OR LUG FACE during PART 3 OR PART 3A --OPTION 2: Do PART 8. (a) --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 5. CONDITION 8: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A --OPTION 2: Do PART 8. (a) --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 4. CONDITION 9: ANY CRACK FOUND IN THE CENTER SEC- TION FRONT SPAR LUG BORE CHAM- FER OR LUG FACE during PART 3A --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 5. CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 4. CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE CHAMFER OR LUG FACE dur- ing PART 3 or PART 3A --OPTION 2: Replace affected upper chord with new upper chord. (b) --OPTION 3: Do PART 10. (b) (c) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 26 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 27 Group 1, Configuration 2; Group 2: Table 3: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC CONDITIONAL INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Before further flight.OPTION 1: Do PART 5. CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE during PART 3 OR PART 3A --OPTION 2: Replace affected upper chord with new upper chord. (b) --OPTION 3: Do PART 10. (b) (c) (a) Refer to Table 4 for post replacement center section inspections. (b) If the denoted action results in the horizontal stabilizer rear spar upper chord being replaced, or it results in the entire horizontal stabilizer being replaced, then hereafter, refer to Table 6 for post replacement horizontal stabilizer inspections. (c) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (d) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles. Group 1, Configuration 2; Group 2: Table 4: POST NEW OR SERVICEABLE CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 4,500 Horizontal Stabilizer Center Section flight cycles after replace- ment. Do PART 2 for any cracks. (d) All airplanes that have re- placed with serviceable center section rear spar upper chord (c) -Within 18,000 Horizontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first, af- ter replacement. All airplanes that have re- placed with a new center section rear spar upper chord (c) 4,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 1: NO CRACK FOUND during PART 2 -Before further flight.Do PART 3 for any crack.CONDITION 2: ANY CRACK FOUND during PART 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 27 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 28 Group 1, Configuration 2; Group 2: Table 4: POST NEW OR SERVICEABLE CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition 4,500 Horizontal Stabilizer Center Section flight cy- cles. -Repeat PART 2 for any crack. (d) CONDITION 5: NO CRACK FOUND during PART 3 -Before further flight.Do PART 3A for any crack.CONDITION 6: ANY CRACK FOUND during PART 3 -Before further flight.OPTION 1: Do PART 4.CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 5.CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 4.CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 5.CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) -Before further flight.OPTION 1: Do PART 4.CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE CHAM- FER OR LUG FACE dur- ing PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (b) -OPTION 3: Do PART 10. (a) (b) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 28 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 29 Group 1, Configuration 2; Group 2: Table 4: POST NEW OR SERVICEABLE CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.OPTION 1: Do PART 5.CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. (b) -OPTION 3: Do PART 10. (a) (b) (a) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (b) If the denoted action results in the horizontal stabilizer rear spar upper chord being replaced, or it results in the entire horizontal stabilizer being replaced, then hereafter, refer to Table 6 for post replacement horizontal stabilizer inspections. (c) Table 3, 5, 6, and 7 are lead in for the post replacement requirements. (d) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles. Table 5: HORIZONTAL STABILIZER REAR SPAR UPPER CHORD LUG DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Within 3,000 Horizon- tal Stabilizer flight cycles or 12 months, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Do PART 2A for any cracks. All airplanes with original or service- able horizontal stabi- lizer rear spar upper chord -Within 3,000 Horizon- tal Stabilizer flight cycles or 12 months, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Within 18,000 Hori- zontal Stabilizer flight cycles or 7 years, whichever occurs first, after replace- ment. All airplanes that have new horizontal stabilizer rear spar upper chord Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 29 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 30 Table 5: HORIZONTAL STABILIZER REAR SPAR UPPER CHORD LUG DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition 3,000 Horizontal Sta- bilizer flight cycles if PART 7A has NOT been accomplished. --Repeat PART 2A for any crack. (d) CONDITION 3: NO CRACK FOUND dur- ing PART 2A 4,500 Horizontal Sta- bilizer flight cycles if PART 7A has been accomplished. - --Before further flight.Do PART 3 for any crack. CONDITION 4: ANY CRACK FOUND dur- ing PART 2A 3,000 Horizontal Sta- bilizer flight cycles if PART 7A has NOT been accomplished. --Repeat PART 2A for any crack. (d) CONDITION 5: NO CRACK FOUND dur- ing PART 3 4,500 Horizontal Sta- bilizer flight cycles if PART 7A has been accomplished. - --Before further flight.Do PART 3A for any crack. CONDITION 6: ANY CRACK FOUND dur- ing PART 3 --Before further flight.OPTION 1: Do PART 4. CONDITION 7: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE CHAM- FER OR LUG FACE during PART 3 or PART 3A --OPTION 2: Do PART 8. (a) --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 5. CONDITION 8: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A --OPTION 2: Do PART 8. (a) --OPTION 3: Do PART 9. (a) (c) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 30 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 31 Table 5: HORIZONTAL STABILIZER REAR SPAR UPPER CHORD LUG DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Before further flight.OPTION 1: Do PART 4. CONDITION 9: ANY CRACK FOUND IN THE CENTER SEC- TION FRONT SPAR LUG BORE CHAM- FER OR LUG FACE during PART 3A --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 5. CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (a) (c) --Before further flight.OPTION 1: Do PART 4. CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE CHAMFER OR LUG FACE dur- ing PART 3 or PART 3A --OPTION 2: Replace affected upper chord with new upper chord. (b) --OPTION 3: Do PART 10. (b) (c) --Before further flight.OPTION 1: Do PART 5. CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A --OPTION 2: Replace affected upper chord with new upper chord. (b) --OPTION 3: Do PART 10. (b) (c) (a) Refer to Table 2 (Group 1, Configuration 1 airplanes) or Table 4 (Group 1, Configuration 2 and Group 2 airplanes) for post replacement center section inspections. (b) If the denoted action results in the horizontal stabilizer rear spar upper chord being replaced, or it results in the entire horizontal stabilizer being replaced, then hereafter, refer to Table 6 for post replacement horizontal stabilizer inspections. (c) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (d) If PART 2A and PART 7A are scheduled to be done concurrently, PART 2A may be deferred for 4,500 Horizontal Stabilizer flight cycles. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 31 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 32 Table 6: POST NEW OR SERVICEABLE HORIZONTAL STABILIZER REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 4,500 Horizontal Stabilizer flight cycles after replacement. Do PART 2A for any cracks. (d) All airplanes that have re- placed with serviceable horizontal stabilizer (c) -Within 18,000 Horizontal Stabilizer flight cycles or 7 years, whichever occurs first, after replacement. All airplanes that have re- placed with a new horizon- tal stabilizer rear spar up- per chord (c) 4,500 Horizontal Stabilizer flight cycles. -Repeat PART 2A for any crack. (d) CONDITION 3: NO CRACK FOUND during PART 2A -Before further flight.Do PART 3 for any crack.CONDITION 4: ANY CRACK FOUND during PART 2A 4,500 Horizontal Stabilizer flight cycles. -Repeat PART 2A for any crack. (d) CONDITION 5: NO CRACK FOUND during PART 3 -Before further flight.Do PART 3A for any crack.CONDITION 6: ANY CRACK FOUND during PART 3 -Before further flight.OPTION 1: Do PART 4.CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A -OPTION 2: Do PART 8. (b) -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A -OPTION 2: Do PART 8. (b) -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 4.CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) (b) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 32 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 33 Table 6: POST NEW OR SERVICEABLE HORIZONTAL STABILIZER REPLACEMENT, DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.OPTION 1: Do PART 5.CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (a) (b) -Before further flight.OPTION 1: Do PART 4.CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE CHAM- FER OR LUG FACE dur- ing PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. -OPTION 3: Do PART 10. (a) -Before further flight.OPTION 1: Do PART 5.CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A -OPTION 2: Replace affect- ed upper chord with new upper chord. -OPTION 3: Do PART 10. (a) (a) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (b) Refer to Table 2 (Group 1, Configuration 1 airplanes) or Table 4 (Group 1, Configuration 2 and Group 2 airplanes) for post replacement center section inspections. (c) Tables 1, 2, 3, 4, 5, and 7 are lead in for the post replacement requirements. (d) If PART 2A and PART 7A are scheduled to be done concurrently, PART 2A may be deferred for 4,500 Horizontal Stabilizer flight cycles. Table 7: SCHEDULED TEARDOWN DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Within 9,000 Horizon- tal Stabilizer Center Section flight cycles or 5 years, whichever occurs first, after the Revision 2 date of this service bulletin. Do PART 7 for any crack. (a) (f) All airplanes with original or service- able center section rear spar upper chord Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 33 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 34 Table 7: SCHEDULED TEARDOWN DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Within 9,000 Horizon- tal Stabilizer flight cycles or 5 years, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Do PART 7A for any crack. (a) (g) All airplanes with original or service- able horizontal stabi- lizer rear spar upper chord. -Within 9,000 Horizon- tal Stabilizer Center Section flight cycles or 5 years, whichever occurs first, after the Revision 2 date of this service bulletin. Within 18,000 Hori- zontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first, after replace- ment. Do PART 7 for any crack. (a) (f) All airplanes that have new center section rear spar up- per chord -Within 9,000 Horizon- tal Stabilizer flight cycles or 5 years, whichever occurs first, after the Revi- sion 2 date of this service bulletin. Within 18,000 Hori- zontal Stabilizer flight cycles or 7 years, whichever occurs first, after replace- ment. Do PART 7A for any crack. (a) (g) All airplanes that have new horizontal stabilizer rear spar upper chord 18,000 Horizontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first. --Repeat PART 7 for any crack. (f) (g) CONDITION 13: NO CRACK FOUND dur- ing PART 7 18,000 Horizontal Stabilizer flight cy- cles or 7 years, whichever occurs first. --Repeat PART 7A for any crack. (f) (g) CONDITION 14: NO CRACK FOUND dur- ing PART 7A --Before further flight.Do PART 3A.CONDITION 15: ANY CRACK FOUND during PART 7 or PART 7A Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 34 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 35 Table 7: SCHEDULED TEARDOWN DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Before further flight.OPTION 1: Do PART 4. CONDITION 7: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE CHAM- FER OR LUG FACE during PART 3A or PART 7 --OPTION 2: Do PART 8. (b) (d) --OPTION 3: Do PART 9. (b) (c) (d) --Before further flight.OPTION 1: Do PART 5. CONDITION 8: ANY CRACK FOUND IN THE CENTER SEC- TION REAR SPAR UPPER CHORD LUG BORE during PART 3A or PART 7 --OPTION 2: Do PART 8. (b) (d) --OPTION 3: Do PART 9. (b) (c) (d) --Before further flight.OPTION 1: Do PART 4. CONDITION 9: ANY CRACK FOUND IN THE CENTER SEC- TION FRONT SPAR LUG BORE CHAM- FER OR LUG FACE during PART 3A or PART 7 --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (b) (c) (d) --Before further flight.OPTION 1: Do PART 5. CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A or PART 7 --OPTION 2: Replace with new front spar. --OPTION 3: Do PART 9. (b) (c) (d) --Before further flight.OPTION 1: Do PART 4. CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE CHAMFER OR LUG FACE dur- ing PART 3A or PART 7A --OPTION 2: Replace affected upper chord with new upper chord. (e) (h) --OPTION 3: Do PART 10. (b) (c) (e) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 35 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 36 Table 7: SCHEDULED TEARDOWN DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance Time (Whichever Occurs Later) ActionCondition --Before further flight.OPTION 1: Do PART 5. CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STA- BILIZER FRONT OR REAR SPAR LUG BORE during PART 3A or PART 7A --OPTION 2: Replace affected upper chord with new upper chord. (e) (h) --OPTION 3: Do PART 10. (b) (c) (e) (a) Center section, left stabilizer and right stabilizer scheduled teardown inspections do not need to be done concurrently; however, all three component teardown inspections must be done within their respective compliance periods given in this table. (b) Refer to Table 8 for post replacement inspections. (c) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (d) Refer to Table 2 (Group 1, Configuration 1 airplanes) or Table 4 (Group 1, Configuration 2 and Group 2 airplanes) for post replacement center section inspections. (e) After replacing the horizontal stabilizer rear spar or the entire horizontal stabilizer, refer to Table 6 for post replacement horizontal stabilizer inspections. (f) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles. (g) If PART 2A and PART 7A are scheduled to be done concurrently, PART 2A may be deferred for 4,500 Horizontal Stabilizer flight cycles. (h) After replacing the horizontal stabilizer rear spar, refer to Table 8 for post replacement inspections. Table 8: POST SCHEDULED TEARDOWN REPLACEMENT DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 18,000 Horizontal Stabilizer Center Section flight cycles or 7 years, whichever occurs first, af- ter replacement. Do PART 7 for any crack. (a) (d) All airplanes that have re- placed the center section rear spar upper chord (c) -Within 18,000 Horizontal Stabilizer flight cycles or 7 years, whichever occurs first, after replacement. Do PART 7A for any crack. (a) (e) All airplanes that have re- placed the horizontal stabi- lizer rear spar upper chord (c) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 36 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 37 Table 8: POST SCHEDULED TEARDOWN REPLACEMENT DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition 18,000 Horizontal Stabiliz- er Center Section flight cy- cles or 7 years, whichever occurs first. -Repeat PART 7 for any crack. (d) (e) CONDITION 13: NO CRACK FOUND during PART 7 18,000 Horizontal Stabiliz- er flight cycles or 7 years, whichever occurs first. -Repeat PART 7A for any crack. (d) (e) CONDITION 14: NO CRACK FOUND during PART 7A -Before further flight.Do PART 3A.CONDITION 15: ANY CRACK FOUND during PART 7 or PART 7A -Before further flight.OPTION 1: Do PART 4.CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3A or PART 7 -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3A or PART 7 -OPTION 2: Do PART 8. -OPTION 3: Do PART 9. (b) -Before further flight.OPTION 1: Do PART 4.CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A or PART 7 -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (b) -Before further flight.OPTION 1: Do PART 5.CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A or PART 7 -OPTION 2: Replace with new front spar. -OPTION 3: Do PART 9. (b) -Before further flight.OPTION 1: Do PART 4.CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE CHAM- FER OR LUG FACE dur- ing PART 3A or PART 7A -OPTION 2: Replace affect- ed upper chord with new upper chord. -OPTION 3: Do PART 10. (b) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 37 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 38 Table 8: POST SCHEDULED TEARDOWN REPLACEMENT DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC) AND DYE PENETRANT INSPECTIONS Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.OPTION 1: Do PART 5.CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZ- ER FRONT OR REAR SPAR LUG BORE during PART 3A or PART 7A -OPTION 2: Replace affect- ed upper chord with new upper chord. -OPTION 3: Do PART 10. (b) (a) Center section, left stabilizer and right stabilizer scheduled teardown inspections do not need to be done concurrently; however, all three component teardown inspections must be done within their respective compliance periods given in this table. (b) The replacement part lugs must be crack free. PART 7 and PART 7A are the methods to determine a crack free replacement part. (c) Table 7 is the lead in for the post replacement requirements. (d) If PART 2 and PART 7 are scheduled to be done concurrently, PART 2 may be deferred for 4,500 Hori- zontal Stabilizer Center Section flight cycles. (e) If PART 2A and PART 7A are scheduled to be done concurrently, PART 2A may be deferred for 4,500 Horizontal Stabilizer flight cycles. 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 Los Angeles Aircraft Certification Office approves the action (i.e. inspection or modification) defined in this service bulletin as an alternative method of compliance to the requirements of paragraph A. and B. of AD 86-12-05, paragraph A. of AD 84-23-05, and paragraph (c) of AD 98-11-04 R1 for inspection detail E-19B listed in Boeing Document No. D6-37089, "Supplemental Structural Inspection Document" (SSID), Revision D. All provisions of AD 86-12-05, AD 84-23-05, and AD 98-11-04 R1 that are not specifically referenced in the above statement remain fully applicable and must be complied with. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 38 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 39 G. Manpower The tables below show an estimate of the task hours necessary to do this change for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. Each table below gives the task hours necessary for each Part of the Work Instructions. Refer to Paragraph 1.E., Compliance, to determine which tables are applicable. PART 2 AND PART 2A: DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND UL- TRASONIC INSPECTIONS Elapsed HoursTask HoursNumber of Per- sons Task 1.751.751Open Access 1.252.502FIGURE 1 1.252.502FIGURE 2 1.751.751Close Access 6.008.5TOTAL FOR EACH AIRPLANE BOLT AND BUSHING REMOVAL/INSPECTION, FABRICATION, AND INSTALLATION Elapsed HoursTask HoursNumber of Per- sons Task 10.2541.004Open Access (a)(a)(a)APPENDIX B 1.002.002FIGURE 8 14.5058.004APPENDIX C 25.75101.00TOTAL FOR EACH AIRPLANE (a) Fabricates parts and as such is considered lost time in Boeing man hour esti- mates. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 39 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 40 PART 9: CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT Elapsed HoursTask HoursNumber of Per- sons Task 14.5058.004PART 9: CENTER SECTION REAR SPAR UPPER CHORD REPLACE- MENT 14.5058.00TOTAL FOR EACH AIRPLANE H. Weight and Balance Changes None. I. Electrical Load Data Not applicable. J. References 1. Existing Data: a. Engineering Change Memo PRR 35005-310RS b. Boeing Service Bulletin 737-55-1026, 737-55-1028, 737-55-1034, 737-55A1029 c. Boeing Service Letter 737-SL-51-042 d. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 81-11-07, 84-23-05, 86-12-05 e. Standard Overhaul Practices Manual (SOPM) 20-10-03, 20-20-02, 20-30-03, 20-41-02, 20-43-03, 20-50-01 f. 737 Non-Destructive Testing (NDT) Manual Part 4, 55-10-17, Part 6, 51-00-00, Part 6, 55-10-04 g. 737-100/200 Aircraft Maintenance Manual (AMM) 12-31-81, 27-41-11, 27-41-131 h. 737-100/200 Structural Repair Manual (SRM) 51-10-01, 55-10-6 2. Data Supplied with this Service Bulletin: a. Drawings: ADCNDCN/REVSheetTitleDrawing No -F2JACKSCREW FITTING, INSTL-CENTER SECTION HORIZONTAL TAIL 65-46847 -YPL --PSDL Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 40 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 41 ADCNDCN/REVSheetTitleDrawing No -C2FRONT SPAR INSTALLATION-HORIZON- TAL TAIL 65-47500 -F3 -E4 -AJPL --PSDL H-2REAR SPAR INSTALLATION HORIZON- TAL STABILIZER 65-47501 E-3 H-4 -AYPL --PSDL -K2CLOSURE RIB INSTALLATION-INBOARD, HORIZONTAL STABILIZER 65-47502 -ACPL --PSDL -E2RIB INSTALLATION-HINGE SUPPORT ELEV, STA 213.32, STAB. 65-47522 -NPL --PSDL K-2RIB INSTALLATION-HINGE SUPPORT, ELEV STA 39.02, STABILIZER 65-47525 -AHPL --PSDL K-2RIB INSTALLATION-HINGE SUPPORT, ELEV STA 66.54, STABILIZER. 65-47526 -E3 -AAPL --PSDL -F2RIB INSTALLATION-T.E. BEAM SUPPORT, ELEV STA 94.07, STABILIZER. 65-47527 -ACPL --PSDL E-2RIB INSTALLATION-HINGE SUPPORT, ELEV STA 121.59, STABILIZER 65-47528 -AGPL -G2RIB INSTL-TE BEAM SUPPORT, ELEV STA 149.12, STABILIZER 65-47529 -AAPL --PSDL Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 41 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 42 ADCNDCN/REVSheetTitleDrawing No -G2RIB INSTALLATION-HINGE SUPPORT, ELEV STA 176.64, STABILIZER 65-47530 -ABPL --PSDL H-2RIB INSTALLATION-TE BEAM SUPPORT ELEV. STA 195.00, STABILIZER 65-47531 -AGPL --PSDL -E2PRIMARY BEAM INSTL-HORIZONTAL TAIL, CENTER SECTION 65-47597 -H2THRUST BEAM INSTL-CENTER SECTION, HORIZONTAL TAIL 65-47598 -H3 -E4 -MPL --PSDL H-2PANEL INSTL-STAB. TRAILING EDGE65-52493 -D3 H-4 -K5 -UPL --PSDL B-1HOLE INSTL-INTERCHANGABILITY CONTROL, HORIZ STABILIZER JOINT 65-52857 -B2 B-3 A-4 --5 -A6 -ADPL --PSDL -H2REMOVABLE LEADING EDGE INSTALLA- TION- HORIZONTAL STABILIZER 65-73783 -H3 -C4 A-5 -AAPL --PSDL Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 42 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 43 ADCNDCN/REVSheetTitleDrawing No -G2STABILIZER, INSPAR AND TE ASSEMBLY65-73794 -E3 -D4 -H5 -H6 -F7 -CFPL --PSDL -A1Horizontal Stabilizer Attach Fittings Bushing Replacement - Kit 65C22125 -EPL --PSDL -G1BUSHING DETAILS - HORIZONTAL STA- BILIZER, VERTICAL FIN AND BODY 69-72039 -G1 G-1 -KPL K-PL 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. K. Publications Affected 1. Publications: Chapter-SectionPublication 27-41737 Aircraft Maintenance 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. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance. Any rework that will require Boeing contact for an approved repair plan will, accordingly, require a Damage Tolerance Evaluation. L. Interchangeability and Intermixability of Parts Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 43 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 44 M. Software Accomplishment Summary None Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 44 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 45 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are not available for the configuration changes, inspection and/or repair procedures given in this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available. NotesNameQTYPart Number / Specifica- tion (d)SPAR CHORD-65-50581-17 (d)SPAR CHORD-65-50581-18 (d)SPAR CHORD-65-50578-13 (d)SPAR CHORD-65-50578-14 (d)FRONT SPAR FITTING-65-47596-6 (d)STAB. ASSY-LH-65-73782-1 (d)STAB ASSY-65-73782-5 (d)STAB ASSY-65-73782-19 (d)STAB. ASSY-RH-65-73782-2 (d)STAB ASSY-65-73782-6 (a) (b)AL-NI-Bronze Bar6 in.AMS 4640 (a)Primer4 ozBMS 10-11, Type 1 (a)Sealant8 ozBMS 5-95 (a)Corrosion Inhibiting Compound8 ozBMS 3-27 or BMS 3-38 (c)Colored Chemical Conversion Coating4 ozSOPM 20-43-03 Type 2, Class A (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 45 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 46 NotesNameQTYPart Number / Specifica- tion (b) Required length is a minimum of six (6) inches. Minimum diameter is 2.600 inches. (c) Refer to SOPM 20-43-03 for material sources. (d) The parts supplied by the operator are based on inspection findings. 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability The operator can supply the tools shown in Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin from PETERSEN, INCORPORATED, 1527 N. 2000 W., OGDEN., UT. 84404-9687. CAO-ADP: S0602A-HQ0339. CAGE Code: 0AL26. Tool price and supply data are not given. 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. NameTool Kit Number Kit Tool - Attach Fitting Bushing Replacement, Horizon- tal Stabilizer MIT65C22125-10 Kit Tool - Attach Fitting Bushing Replacement, Horizon- tal Stabilizer. Center Sect. MIT65C22125-20 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 46 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 47 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque Values: — Values for structural fasteners are given in 737 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 737 Aircraft Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). — Values for engine maintenance tasks are included in Chapter 70 of 737 Aircraft Maintenance Manual (AMM). — Non-standard torque values for maintenance tasks are included in the applicable installation step. 4. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 5. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate full threaded fasteners (screws) needed for installation in this service bulletin. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 47 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 48 7. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 8. Boeing Service Letter 737-SL-51-042, Damage Reporting and Repair Plan/Design Guidelines, is an acceptable procedure to request information from Boeing for additional structural repair instructions. The Service Letter describes what information must be provided to Boeing before a structural repair can be provided. 9. Refer to APPENDIX A to find definitions for 0.780 inch and 0.932 inch thick rear spar upper lugs. 10. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 11. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. 12. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 13. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems. 14. Use of colors in Figures is based on guidance from the ATA e-Business Program (ATA) iSpec 2200. 15. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. 16. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. B. WORK INSTRUCTIONS PART 1: ACCESS 1. Remove access panels 9123, 9124, 9223, and 9224 on the horizontal stabilizer upper and lower surfaces. Refer to 737-100/200 AMM 12-31-81 as an accepted procedure. PART 2: CENTER SECTION REAR SPAR UPPER CHORD CLEVIS LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS 1. Do Detailed, HFEC, and Ultrasonic Inspections for any crack in accordance with FIGURE 1. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 48 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 49 a. CONDITION 1: NO CRACK FOUND (1) Do PART 11: CLOSE ACCESS. (2) Put airplane back to a serviceable condition. b. CONDITION 2: ANY CRACK FOUND (1) Do PART 3: CENTER SECTION AND HORIZONTAL STABILIZER REAR SPAR UPPER CHORD CONDITIONAL TEARDOWN INSPECTION. PART 2A: HORIZONTAL STABILIZER REAR UPPER LUGS DETAILED, HIGH FREQUENCY EDDY CURRENT (HFEC), AND ULTRASONIC INSPECTIONS 1. Do Detailed, HFEC, and Ultrasonic Inspections for any crack in accordance with FIGURE 2. a. CONDITION 3: NO CRACK FOUND (1) Do PART 11: CLOSE ACCESS. (2) Put airplane back to a serviceable condition. b. CONDITION 4: ANY CRACK FOUND (1) Do PART 3: CENTER SECTION AND HORIZONTAL STABILIZER REAR SPAR UPPER CHORD CONDITIONAL TEARDOWN INSPECTION. PART 3: CENTER SECTION AND HORIZONTAL STABILIZER REAR SPAR UPPER CHORD CONDITIONAL TEARDOWN INSPECTION 1. Remove the affected horizontal stabilizer(s). Refer to 737-100/200 AMM 27-41-11 as an accepted procedure. 2. Remove the bushing(s) from the affected lug(s). Refer to 737-100/200 AMM 27-41-131 as an accepted procedure. 3. Do HFEC and Fluorescent Dye Penetrant Inspections on the affected lug(s) in accordance with FIGURE 3 and FIGURE 4. a. CONDITION 5: NO CRACK FOUND (1) Do PART 6: INSTALLATION. (2) Do PART 11: CLOSE ACCESS. (3) Put the airplane back to a serviceable condition. b. CONDITION 6: ANY CRACK FOUND (1) Do PART 3A: CENTER SECTION AND HORIZONTAL STABILIZER FRONT AND REAR LUG CONDITIONAL TEARDOWN INSPECTION Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 49 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 50 PART 3A: CENTER SECTION AND HORIZONTAL STABILIZER FRONT AND REAR LUG CONDITIONAL TEARDOWN INSPECTION 1. Remove the remaining horizontal stabilizer if not previously removed. Refer to 737-100/200 AMM 27-41-11 as an accepted procedure. 2. Remove remaining bushings and sleeves from the horizontal stabilizer and center section front and rear spar upper lugs. Refer to 737-100/200 AMM 27-41-131 as an accepted procedure. 3. Do HFEC and Fluorescent Dye Penetrant Inspections in accordance with FIGURE 5 and FIGURE 6, if not previously completed. a. CONDITION 7: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A or PART 7 (1) OPTION 1: (a) Do PART 4: LUG REPAIR. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Do PART 8: NEW CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT. (3) OPTION 3: (a) Do PART 9: SERVICEABLE CENTER SECTION REPLACEMENT. b. CONDITION 8: ANY CRACK FOUND IN THE CENTER SECTION REAR SPAR UPPER CHORD LUG BORE during PART 3 or PART 3A or PART 7 (1) OPTION 1: (a) Do PART 5: LUG REPAIR - BORE OVERSIZE. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Do PART 8: NEW CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT. (3) OPTION 3: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 50 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 51 (a) Do PART 9: SERVICEABLE CENTER SECTION REPLACEMENT. c. CONDITION 9: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE CHAMFER OR LUG FACE during PART 3A or PART 7 (1) OPTION 1: (a) Do PART 4: LUG REPAIR. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Replace with a new front spar in accordance with the table that follows. Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )FRONT SPAR FITTING65-47596-6 (a) THRUST BEAM INSTL- CENTER SECTION, HORIZONTAL TAIL 65-47598-( ) PRIMARY BEAM INSTL- HORIZONTAL TAIL, CEN- TER SECTION 65-47597-( ) JACKSCREW FITTING, INSTL-CENTER SECTION HORIZONTAL TAIL 65-46847-( ) (a) 65-47596-502 Stabilizer Center Section Front Spar Assemblies, delivered on some group 1 airplanes, are not acceptable front spar replacements. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (3) OPTION 3: (a) Do PART 9: SERVICEABLE CENTER SECTION REPLACEMENT. d. CONDITION 10: ANY CRACK FOUND IN THE CENTER SECTION FRONT SPAR LUG BORE during PART 3A or PART 7 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 51 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 52 (1) OPTION 1: (a) Do PART 5: LUG REPAIR - BORE OVERSIZE. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Replace with a new front spar in accordance with the table that follows. Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )FRONT SPAR FITTING65-47596-6 (a) THRUST BEAM INSTL- CENTER SECTION, HORIZONTAL TAIL 65-47598-( ) PRIMARY BEAM INSTL- HORIZONTAL TAIL, CEN- TER SECTION 65-47597-( ) JACKSCREW FITTING, INSTL-CENTER SECTION HORIZONTAL TAIL 65-46847-( ) (a) 65-47596-502 Stabilizer Center Section Front Spar Assemblies, delivered on some group 1 airplanes, are not acceptable front spar replacements. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (3) OPTION 3: (a) Do PART 9: SERVICEABLE CENTER SECTION REPLACEMENT. e. CONDITION 11: ANY CRACK FOUND IN THE HORIZONTAL STABILIZER FRONT OR REAR SPAR LUG BORE CHAMFER OR LUG FACE during PART 3 or PART 3A or PART 7A (1) OPTION 1: (a) Do PART 4: LUG REPAIR. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 52 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 53 (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Replace affected upper chord with new upper chord in accordance with the table that follows. Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )Front Spar Left Side Front Spart Right Side 65-50581-17 65-50581-18 FRONT SPAR INSTALLA- TION-HORIZONTAL TAIL 65-47500-( ) CLOSURE RIB INSTALLA- TION-INBOARD, HORI- ZONTAL STABILIZER 65-47502-( ) STABILIZER, INSPAR AND TE ASSEMBLY 65-73794-( ) REMOVABLE LEADING EDGE INSTALLATION- HORIZONTAL STABILIZ- ER 65-73783-( ) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 53 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 54 Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )Rear Spar Left Side Rear Spar Right Side 65-50578-13 65-50578-14 REAR SPAR INSTALLA- TION HORIZONTAL STA- BILIZER 65-47501-( ) CLOSURE RIB INSTALLA- TION-INBOARD, HORI- ZONTAL STABILIZER 65-47502-( ) STABILIZER, INSPAR AND TE ASSEMBLY 65-73794-( ) RIB INSTALLATION- HINGE SUPPORT ELEV, STA 213.32, STAB. 65-47522-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 39.02, STABILIZER 65-47525-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 66.54, STABILIZER. 65-47526-( ) RIB INSTALLATION-T.E. BEAM SUPPORT, ELEV STA 94.07, STABILIZER. 65-47527-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 121.59, STABILIZER 65-47528-( ) RIB INSTL-TE BEAM SUPPORT, ELEV STA 149.12, STABILIZER 65-47529-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 176.64, STABILIZER 65-47530-( ) RIB INSTALLATION-TE BEAM SUPPORT ELEV. STA 195.00, STABILIZER 65-47531-( ) PANEL INSTL-STAB. TRAILING EDGE 65-52493-( ) (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 54 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 55 (3) OPTION 3: (a) Do PART 10: SERVICEABLE HORIZONTAL STABILIZER REPLACEMENT. f. CONDITION 12: ANY CRACK FOUND IN THE HORIZONTAL STABILIZER FRONT OR REAR SPAR LUG BORE during PART 3 or PART 3A or PART 7A (1) OPTION 1: (a) Do PART 5: LUG REPAIR - BORE OVERSIZE. (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. (2) OPTION 2: (a) Replace affected upper chord with new upper chord in accordance with the table that follows. Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )Front Spar Left Side Front Spart Right Side 65-50581-17 65-50581-18 FRONT SPAR INSTALLA- TION-HORIZONTAL TAIL 65-47500-( ) CLOSURE RIB INSTALLA- TION-INBOARD, HORI- ZONTAL STABILIZER 65-47502-( ) STABILIZER, INSPAR AND TE ASSEMBLY 65-73794-( ) REMOVABLE LEADING EDGE INSTALLATION- HORIZONTAL STABILIZ- ER 65-73783-( ) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 55 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 56 Drawing TitleDrawingPart DescriptionPart Number HOLE INSTL-INTER- CHANGABILITY CON- TROL, HORIZ STABILIZ- ER JOINT 65-52857-( )Rear Spar Left Side Rear Spar Right Side 65-50578-13 65-50578-14 REAR SPAR INSTALLA- TION HORIZONTAL STA- BILIZER 65-47501-( ) CLOSURE RIB INSTALLA- TION-INBOARD, HORI- ZONTAL STABILIZER 65-47502-( ) STABILIZER, INSPAR AND TE ASSEMBLY 65-73794-( ) RIB INSTALLATION- HINGE SUPPORT ELEV, STA 213.32, STAB. 65-47522-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 39.02, STABILIZER 65-47525-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 66.54, STABILIZER. 65-47526-( ) RIB INSTALLATION-T.E. BEAM SUPPORT, ELEV STA 94.07, STABILIZER. 65-47527-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 121.59, STABILIZER 65-47528-( ) RIB INSTL-TE BEAM SUPPORT, ELEV STA 149.12, STABILIZER 65-47529-( ) RIB INSTALLATION- HINGE SUPPORT, ELEV STA 176.64, STABILIZER 65-47530 RIB INSTALLATION-TE BEAM SUPPORT ELEV. STA 195.00, STABILIZER 65-47531-( ) PANEL INSTL-STAB. TRAILING EDGE 65-52493-( ) (b) Do PART 6: INSTALLATION. (c) Do PART 11: CLOSE ACCESS. (d) Put the airplane back to serviceable condition. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 56 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 57 (3) OPTION 3: (a) Do PART 10: SERVICEABLE HORIZONTAL STABILIZER REPLACEMENT. PART 4: LUG REPAIR 1. Remove the crack in the lug, in accordance with 737-100/200 SRM 51-10-01. 2. Contact Boeing to evaluate the repair and possibly get additional work instructions for the repair for this service bulletin, and do the work instructed by Boeing. PART 5: LUG REPAIR - BORE OVERSIZE 1. Oversize the bore until the crack is removed. NOTE: Make sure the crack is removed by performing an HFEC inspection of the lug bore in accordance with 737 NDT Manual Part 6, 51-00-00, Procedure 1 or Procedure 11 or Procedure 16. 2. Oversize the bore an additional 0.0625 - 0.0633 inch diameter. 3. Contact Boeing to evaluate the repair and possibly get additional work instructions for the repair for this service bulletin, and do the work instructed by Boeing. PART 6: INSTALLATION 1. Prepare the lugs, only at the affected location(s), in accordance with FIGURE 7. 2. Fabricate new bushings and sleeves, only for the affected location(s), in accordance with APPENDIX B. 3. Install, only at the affected location(s), the bushings and sleeves in accordance with FIGURE 8. 4. Install the affected horizontal stabilizer(s) as follows: a. Refer to 737-100/200 AMM 27-41-11 as an accepted procedure, EXCEPT in lieu of Section E, do bolt installation in accordance with APPENDIX C. PART 7: CENTER SECTION SCHEDULED TEARDOWN INSPECTION 1. Remove the affected horizontal stabilizer(s). Refer to 737-100/200 AMM 27-41-11 as an accepted procedure. 2. Remove bushings from the affected center section front and rear spar upper chord clevis lugs. Refer to 737-100/200 AMM 27-41-131 as an accepted procedure. 3. Do HFEC and Fluorescent Dye Penetrant Inspections in accordance with FIGURE 5. a. CONDITION 13: NO CRACK FOUND (1) Do PART 6: INSTALLATION. (2) Do PART 11: CLOSE ACCESS. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 57 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 58 (3) Put the airplane back to a serviceable condition. b. CONDITION 15: ANY CRACK FOUND (1) Do PART 3A: CENTER SECTION AND HORIZONTAL STABILIZER FRONT AND REAR LUG CONDITIONAL TEARDOWN INSPECTION. PART 7A: HORIZONTAL STABILIZER SCHEDULED TEARDOWN INSPECTION 1. Remove affected horizontal stabilizers. Refer to 737-100/200 AMM 27-41-11 as an accepted procedure. 2. Remove all bushings and sleeves from the affected horizontal stabilizer front and rear spar upper chord lugs. Refer to 737-100/200 AMM 27-41-131 as an accepted procedure. 3. Do HFEC and Fluorescent Dye Penetrant Inspections in accordance with FIGURE 6. a. CONDITION 14: NO CRACK FOUND (1) Do PART 6: INSTALLATION. (2) Do PART 11: CLOSE ACCESS. (3) Put the airplane back to a serviceable condition. b. CONDITION 15: ANY CRACK FOUND (1) Do PART 3A: CENTER SECTION AND HORIZONTAL STABILIZER FRONT AND REAR LUG CONDITIONAL TEARDOWN INSPECTION. PART 8: NEW CENTER SECTION REAR SPAR UPPER CHORD REPLACEMENT 1. Replace the center section rear spar upper chord with a new part in accordance with Boeing Service Bulletin 737-55-1034 Part III. 2. Do PART 6: INSTALLATION. 3. Do PART 11: CLOSE ACCESS. 4. Return airplane to serviceable condition. PART 9: SERVICEABLE CENTER SECTION REPLACEMENT 1. Replace the center section with a serviceable center section assembly number 65-73781-501 in accordance with 737-100/200 SRM 55-10-6. NOTE: Center section assemblies part number 65-73781-2, delivered on group 1 airplanes, are not acceptable center section replacements. 2. Do PART 6: INSTALLATION. 3. Do PART 11: CLOSE ACCESS. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 58 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 59 4. Return airplane to a serviceable condition. PART 10: SERVICEABLE HORIZONTAL STABILIZER REPLACEMENT 1. Get a serviceable horizontal stabilizer in accordance with the table that follows: Part DescriptionPart Number LEFT SIDE STAB. ASSY65-73782-1 LEFT SIDE STAB ASSY65-73782-5 LEFT SIDE STAB. ASSY65-73782-19 RIGHT SIDE STAB. ASSY65-73782-2 RIGHT SIDE STAB. ASSY65-73782-6 2. Do PART 6: INSTALLATION. 3. Do PART 11: CLOSE ACCESS. 4. Return airplane to a serviceable condition. PART 11: CLOSE ACCESS 1. Install access panels 9123, 9124, 9223, and 9224 on the horizontal stabilizer upper and lower surfaces. Refer to 737-100/200 AMM 12-31-81 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 12, 1985 737-55A1033Revision 2: August 07, 2015 59 of 103 BOEING SERVICE BULLETIN 737-55A1033 ALERTALERT ### Page 60 (OCR) BOEING SERVICE BULLETIN 737-55A1033 ALERT ALERT HORIZONTAL STABILIZER CENTER SECTION REAR SPAR UPPER CHORD OR B LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE 2350415 FIGURE 1: CENTER SECTION REAR SPAR UPPER CLEVIS LUGS DETAILED, HFEC, AND ULTRASONIC INSPECTIONS (SHEET 1 OF 3) Original Issue: April 12, 1985 Revision 2 August 07, 2015 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 737-55A1033 Work - See page 1 for details. 60 of 103 The text continues at https://openairdocs.org/service-documents/boeing/737-55a1033/file/80ea7f0858e7.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.