# Boeing Alert Service Bulletin 737-57A1271: U.S. DOT/FAA - Service Information - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2012-1068; AD 2013-09-02 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Alert Service Bulletin 737-57A1271](https://openairdocs.org/service-documents/boeing/737-57a1271.md) - Title as filed: U.S. DOT/FAA - Service Information - Pages: 77 - PDF: https://openairdocs.org/files/sha256/fc/3a/fc3ab069e51d03da5ff568fcf4c4e2c7027071ff91d960232c0408b3c3bcb30a - Page: https://openairdocs.org/service-documents/boeing/737-57a1271/file/fc3ab069e51d ## 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 Number: 737-57A1271 Original Issue: September 11, 2003 Revision 3: February 13, 2012 ATA System: 5752 SUBJECT: WINGS - Trailing Edge And Trailing Edge Devices - Trailing Edge Flaps - Outboard Flap, Inboard Track Inspection/Overhaul/Replacement at WBL 254 Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2003 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 1 of 77 4.0 ### Page 2 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 2 of 77 BOEING SERVICE BULLETIN 737-57A1271 BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet ............................................ 5 Summary ...................................................... 7 1. PLANNING INFORMATION ........................................ 1 1 A. Effectivity ............................................... 1 1 1. Airplanes ............................................ 1 1 2. Spares Affected ........................................ 2 3 B. Concurrent Requirements ...................................... 2 3 C. Reason ................................................ 2 3 D. Description .............................................. 2 5 E. Compliance .............................................. 2 6 F. Approval ............................................... 2 7 G. Manpower .............................................. 2 8 H. Weight and Balance Changes .................................... 2 8 I. Electrical Load Data ......................................... 2 8 J. References .............................................. 2 9 1. Existing Data: ......................................... 2 9 2. Data supplied with this Service Bulletin: ........................... 3 0 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 3 0 K. Publications Affected ........................................ 3 0 L. Interchangeability and Intermixability of Parts ........................... 3 0 2. MATERIAL INFORMATION ........................................ 3 1 A. Material - Price and Availability ................................... 3 1 B. Industry Support Information .................................... 3 1 C. Parts Necessary For Each Airplane ................................. 3 1 1. Kits/Parts: ........................................... 3 1 2. Parts and Materials Supplied by the Operator: ........................ 3 1 3. Parts Modified and Reidentified: ............................... 3 3 4. Parts Removed and Not Replaced: .............................. 3 3 D. Parts Necessary to Change Spares ................................. 3 3 E. Special Tooling - Price and Availability ............................... 3 3 F. Special Tooling Necessary to do this Service Bulletin ....................... 3 3 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 3 5 A. GENERAL INFORMATION ..................................... 3 5 B. WORK INSTRUCTIONS ....................................... 3 6 FIGURE 1: INSPECTION - TRACK WEBS AND FLANGES ....................... 4 2 FIGURE 2: INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED .......... 4 4 FIGURE 3: INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED ........ 4 6 FIGURE 4: REPLACEMENT - ANTI-FRET STRIP ............................ 4 8 FIGURE 5: REPLACEMENT - TAPERED SHIM .............................. 5 0 FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT ..................... 5 2 FIGURE 7: ALIGNMENT - TRACK INSTALLATION ............................ 5 7 FIGURE 8: INSTALLATION - NEW SPARES TRACK - GROUP 1 AIRPLANES - 737-100/200 .... 6 3 FIGURE 9: INSTALLATION - NEW SPARES TRACK - GROUP 3 AIRPLANES - 737-300/400/500 . . 68 FIGURE 10: SHOP AID - PRESSURE PLATE ............................... 7 2 FIGURE 11: TRACK OVERHAUL - SUPPLEMENTAL INSTRUCTIONS TO OHM 57-53-15 ...... 7 3 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 3 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 4 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 4 of 77 BOEING SERVICE BULLETIN 737-57A1271 BLANK PAGE ### Page 5 Commercial Airplanes 737 Service Bulletin Revision Transmittal SheetNumber: 737-57A1271Original Issue: September 11, 2003 Revision 3: February 13, 2012 ATA System: 5752 SUBJECT: WINGS - Trailing Edge And Trailing Edge Devices - Trailing Edge Flaps - Outboard Flap, Inboard Track Inspection/Overhaul/Replacement at WBL 254 This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION No more work is necessary on the airplane(s) changed in accordance with Revision 2 of this service bulletin. Federal Aviation Administration (FAA) Airworthiness Directive AD 78-13-07, AD 90-06-02, AD 2000-25-07 & AD 2002-05-07 are related to this service bulletin. REASON FOR REVISION This revision is sent to incorporate Information Notice 737-57A1271 IN 02. This Information Notice informed operators that sheet 2 of 3 in Figure 1 should be ignored. References to the related AD's were added and additional notes were added to section 3.A. General Information. These sections were changed: 1. Figure 1 was revised to remove the graphic on sheet 2 of 3. 2. 3.A. General Information, additional notes were added. 3. 1.F. Approval, updated to the current statement. The data given in Information Notice 737-57A1271 IN 02 is included in this revision. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. REVISION HISTORY September 11, 2003Original Issue: July 30, 2008Revision 1: January 17, 2011Revision 2: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 5 of 77 ### Page 6 February 13, 2012Revision 3: BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 6 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 7 Commercial Airplanes 737 Service Bulletin SummaryNumber: 737-57A1271Original Issue: September 11, 2003 Revision 3: February 13, 2012 ATA System: 5752 SUBJECT: WINGS - Trailing Edge And Trailing Edge Devices - Trailing Edge Flaps - Outboard Flap, Inboard Track Inspection/Overhaul/Replacement at WBL 254 CONCURRENT REQUIREMENTS None. BACKGROUND This service bulletin gives the instructions to inspect, repair, overhaul, and replace the flap track at Wing Buttock Line (WBL) 254. Since 1989, Boeing has more than thirty reports of cracks in the flap track at WBL 254. Cracks were found in the area of the rear spar attachment, in the track webs, and in the upper and lower flanges at the aft end of the track. The cracks in the area of the rear spar attachment were found at the edge of the hole for the outboard bolt, or at the outer edge of the flange adjacent to the outboard bolt. The cracks in the upper and lower flanges were 0.1 to 1.5 inches in length, and the cracks in the aft end of the webs were 0.75 to 7.0 inches in length. In one incident the aft end of a track had cracks through the two lower flanges, through the two webs, and through the fail-safe spacer. The two upper flanges were all that kept the aft end attached to the remaining part of the track. Also, a track was found with cracks through the two upper and two lower flanges, and through the two webs. The fail-safe spacer was all that kept the aft end of this track attached. This track also had a piece broken out in the curved area of the upper outboard flange. Some of the reports also show that tracks were found loose and had corrosion in the area of the rear spar attachment. These tracks that were found loose also had damaged, or missing, anti-fret strips and tapered shims. Initially, the loose tracks were thought to be caused by a weak bond of, or compression damage to, the phenolic anti-fret strip installed in the joint between the track and rear spar. But, subsequent reports showed that the sequence and procedures used during track installation could also be a cause of loose tracks. During installation, when full torque is applied to the forward attach bolt, it can cause the track to move laterally at the rear spar joint. If the track moves laterally at the rear spar joint during the installation procedures, it can put a side load on the inboard aft attach bolt. Then, when the inboard aft attach bolt is tightened to the specified torque value, some of the torque can be absorbed by friction. Subsequently, because of the friction, the torque applied to the bolt is not sufficient to hold the track tight against the rear spar structure. Continued operation with a cracked and/or loose attachment at the rear spar could cause the track to break. A result of a broken track could be the loss of the outboard trailing edge flap, and may preclude continued safe flight and landing of the airplane. The new spares track assemblies have increased upper flange thickness in the attachment area that mates with the wing rear spar, and improved coatings and processes for corrosion protection. The new track for the 737-100/200 also has an improved fail-safe configuration at the forward end that makes it comparable to the 737-300/400/500 track assembly. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 7 of 77 ### Page 8 The inspections given in this service bulletin will find the conditions that make repair or replacement of the flap track necessary. The repairs, scheduled overhauls, correct alignment during installation, and regularly scheduled maintenance will keep tracks in a serviceable condition. There is no terminating action for this service bulletin. This service bulletin replaces Service Bulletins 737-57A1082, 737-57A1249, and 737-57A1265. Boeing Service Related Problem (SRP) 737-SRP-57-0131 is related to this service bulletin. ACTION (PRR 35005-238RS) Do an initial inspection of the track webs, track flanges, and the track-to-wing attachment at WBL 254. Look for stop-drill repairs and cracks in the track webs. Look for stop-drill repairs, cracks, nicks, corrosion pits, galling, and other signs of damage on the track flanges. Look for corrosion, loose bolts, and a damaged or a missing anti-fret strip and/or tapered shim at the track-to-wing attachment. Remove a track from service if it has a stop-drill repair. If possible, make repairs to the edges of the track flange, but replace the track if cracks are found in the webs. Disassemble the track-to-wing joint and do more inspections if signs of corrosion, loose bolts, or a damaged or missing anti-fret strip or tapered shim are found. If necessary make and install a new anti-fret strip, and/or tapered shim, and remove corrosion and make repairs to the track. Do the procedures to correctly align the track during assembly of the track-to-wing joint. If the track cannot be repaired, install a serviceable flap track assembly. During installation of a serviceable flap assembly, do the procedures to correctly align the track during installation. Do the repeat inspections and schedule the initial, and repeat overhaul, of a flap track at the times given in Paragraph 1.E., Compliance. Flap track assemblies with short fail-safe bars, part number 65-46428-31 and 65-46428-33 must be removed from service during inspection or repair. EFFECTIVITY All 737-100, -200, -200C, -300, -400, and -500 airplanes line numbers 1 through 3132. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 78-13-07, AD 90-06-02, AD 2000-25-07 & AD 2002-05-07 are related to this service bulletin. Refer to Paragraph 1.E., Compliance, for the repeat inspection and overhaul thresholds. 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. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the inspection, and/or repair procedures, given in this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 8 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 9 (OCR) BOEING SERVICE BULLETIN 737-57A1271 MANPOWER Airplanes Total Task Hours Elapsed Hours All 82 23 MATERIAL INFORMATION Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability. WBL INSPECT TRACK WEB 254 AND FLANGES SEE LEFT WING SHOWN FWDY RIGHT WING SIMILAR A-A (EXAMPLE - CRACKS AND DAMAGE) ATTACH BOLTS AFT TRACK SUPPORT FITTING LOWER WING SKIN REAR SPAR INSPECT TRACK CHORD ATTACHMENT OVERHAUL TRACKS AT NEW INTERVALS. FOR INCREASED CORROSION PROTECTION FWD, AND SERVICE LIFE, REPLACE TRACKS WITH NEW SPARES TRACKS. > INBD FLAP TRACKS 2 AND 7 N85000 Original Issue: September 11, 2003 Revision 3: February 13, 2012 737-57A1271 Copyright © Unpublished Work - See page 1 for details. BOEING PROPRIETARY - 9 of 77 ### Page 10 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 10 of 77 BOEING SERVICE BULLETIN 737-57A1271 BLANK PAGE ### Page 11 Commercial Airplanes 737 Service Bulletin Number: 737-57A1271 Original Issue: September 11, 2003 Revision 3: February 13, 2012 ATA System: 5752 SUBJECT: WINGS - Trailing Edge And Trailing Edge Devices - Trailing Edge Flaps - Outboard Flap, Inboard Track Inspection/Overhaul/Replacement at WBL 254 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. DESCRIPTIONCONFIGURATIONGROUP 737-100/-200/-200C, airplanes with flap track assemblies 65-46428-() or 65C35380-(). Inspection, overhaul and replacement instructions given are applicable to Group 1 airplanes -1 737-200/-200C, airplanes with flap track assemblies 65-67158-() or 65C35380-(). If necessary, these tracks can be replaced with 65-67158-6. -2 737-300/400/500 airplanes with 65-46428-(), 65C35616-(), 65C35387-(), 65C34812-() or 65C35380-() flap track assemblies. The inspection, overhaul, and replacement instructions given in this service bulletin are applicable to Group 3 airplanes. -3 Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 GroupVariable Number 1PA001 - PA022 1PA099 1PA231 - PA232 2PC001 - PC005 1PG001 - PG075 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 11 of 77 ### Page 12 GroupVariable Number 1PG199 1PG201 - PG230 1PG251 - PG255 1PG271 - PG279 1PG301 - PG314 1PG331 - PG332 1PG351 - PG356 1PG375 1PG401 - PG403 1PG431 - PG442 1PG471 - PG475 1PG501 - PG505 1PG571 - PG586 1PG621 - PG630 1PG651 - PG652 1PG701 - PG705 1PH001 1PH011 - PH013 1PH021 - PH024 1PH701 - PH715 1PH731 - PH732 1PH741 - PH743 2PJ001 - PJ002 1PJ003 - PJ009 2PJ031 - PJ032 2PJ071 - PJ072 2PJ101 - PJ104 1PJ105 - PJ119 1PJ201 - PJ219 3PJ301 - PJ302 3PJ551 - PJ561 3PJ601 - PJ615 3PJ811 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 12 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 13 GroupVariable Number 3PJ816 - PJ817 1PK026 - PK029 1PK041 - PK053 1PK061 - PK070 1PK081 - PK082 1PK091 - PK099 1PK101 - PK103 1PK111 - PK120 1PK141 - PK146 1PK201 - PK204 1PK211 - PK223 1PK231 - PK241 1PK251 - PK258 1PK271 - PK274 1PK281 - PK289 1PK291 1PK301 - PK318 1PK341 1PK351 - PK361 1PK391 1PK431 - PK433 1PK451 - PK452 1PK461 - PK469 1PK495 1PK501 - PK504 1PK511 - PK515 1PK519 1PK521 - PK528 1PK541 - PK565 1PK581 1PK591 - PK599 1PK601 - PK617 1PK621 - PK637 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 13 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 14 GroupVariable Number 1PK641 - PK642 1PK661 - PK666 1PK671 - PK681 1PK691 - PK697 1PK711 - PK716 1PK731 - PK765 1PK771 - PK779 1PK801 - PK804 1PK819 - PK827 1PK830 1PK861 - PK863 1PK871 - PK874 1PK881 - PK884 1PK901 - PK938 1PK971 - PK974 1PL001 - PL028 1PL061 1PL081 1PL101 - PL113 1PL151 1PL171 - PL172 1PL201 - PL203 1PL221 1PL401 - PL417 1PL421 1PL441 1PL451 - PL456 1PL471 1PL491 1PL501 - PL506 1PL551 - PL562 1PL581 1PL601 - PL603 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 14 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 15 GroupVariable Number 1PL611 1PL621 - PL626 1PL631 - PL632 1PL711 - PL712 1PL716 - PL747 1PL756 1PL758 1PL761 - PL770 1PL781 - PL788 1PL793 2PL801 - PL803 1PM001 - PM006 1PM016 - PM017 1PM021 - PM023 1PM051 - PM066 1PM101 - PM119 1PM141 - PM142 1PM171 1PM181 1PM251 - PM255 1PM281 - PM283 3PM381 - PM399 3PM401 - PM417 3PM541 - PM564 1PN001 - PN002 1PN021 - PN043 1PN081 - PN086 1PN101 - PN117 1PN131 - PN163 1PN401 - PN420 1PN431 - PN433 1PN451 - PN456 1PN471 - PN474 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 15 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 16 GroupVariable Number 1PN481 1PN491 - PN493 1PN501 - PN502 1PN511 - PN512 1PN521 3PP001 - PP054 3PP101 - PP169 3PP181 - PP199 3PP201 - PP205 3PP221 3PP231 - PP243 3PP281 - PP286 3PP301 - PP305 3PP351 - PP353 3PP376 - PP384 3PP391 - PP393 3PP401 - PP440 3PP471 - PP475 3PP501 - PP522 3PP631 - PP634 3PP651 - PP652 3PP671 - PP699 3PP701 - PP733 3PP771 - PP779 3PP801 - PP808 3PP821 - PP827 3PP831 - PP848 3PP851 - PP852 3PP861 - PP877 3PP891 - PP899 3PP901 - PP936 3PP946 - PP948 3PP951 - PP952 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 16 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 17 GroupVariable Number 3PP961 - PP967 3PP981 - PP991 3PP993 3PQ001 - PQ016 3PQ026 - PQ041 3PQ051 - PQ092 3PQ101 - PQ199 3PQ201 - PQ202 3PQ221 - PQ237 3PQ241 - PQ243 3PQ251 - PQ267 3PQ281 - PQ299 3PQ301 - PQ307 3PQ331 - PQ332 3PQ341 - PQ348 3PQ361 - PQ373 3PQ391 - PQ395 3PQ401 - PQ418 3PQ421 3PQ431 - PQ438 3PQ447 - PQ448 3PQ451 3PQ454 3PQ471 - PQ475 3PQ479 - PQ481 3PQ486 - PQ487 3PQ491 - PQ493 3PQ771 - PQ772 3PQ791 - PQ793 3PQ801 - PQ805 3PQ931 - PQ935 3PQ951 3PQ971 - PQ997 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 17 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 18 GroupVariable Number 3PR001 - PR017 3PR021 - PR034 3PR041 - PR045 3PR061 - PR072 3PR077 - PR082 3PR091 - PR092 3PR096 3PR101 3PR121 - PR122 3PR131 - PR132 3PR141 - PR143 3PR161 - PR172 3PR181 3PS601 - PS631 3PS636 - PS638 3PS641 - PS644 3PS651 - PS657 3PS666 - PS669 3PS691 - PS692 3PS701 - PS706 3PS751 - PS799 3PS811 3PS836 - PS837 3PS841 - PS846 3PS851 - PS852 3PS856 3PS861 - PS863 3PS866 - PS868 3PS871 - PS874 3PS896 - PS897 3PS901 - PS941 3PS956 - PS957 3PS961 - PS963 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 18 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 19 GroupVariable Number 3PS971 - PS978 3PT001 - PT015 3PT021 - PT031 3PT041 - PT064 3PT101 - PT105 3PT121 - PT138 3PT146 - PT148 3PT161 - PT170 3PT181 - PT188 3PT211 - PT220 3PT295 3PT301 - PT309 3PT331 - PT360 3PT381 - PT399 3PT401 - PT438 3PT501 - PT517 3PT561 - PT565 3PT581 - PT586 3PT611 - PT621 3PT641 - PT644 3PT651 - PT656 3PT671 - PT672 3PT681 - PT685 3PT701 - PT703 3PT716 - PT717 3PT721 - PT725 3PT801 - PT834 3PT851 - PT854 3PT871 - PT886 3PT901 - PT930 3PT971 - PT973 3PT981 - PT985 3PT996 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 19 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 20 GroupVariable Number 3PU001 - PU025 3PU301 3PU311 - PU313 3PV001 - PV055 3PV201 - PV209 3PV226 - PV229 3PV231 - PV237 3PV271 - PV272 3PV281 - PV287 3PV296 3PV301 - PV302 3PV351 3PV356 - PV357 3PW001 - PW054 3PW061 - PW068 3PW072 3PW086 - PW088 3PW091 - PW094 3PW101 - PW102 3PW106 3PW111 - PW120 3PW156 - PW157 3PW161 - PW171 3PW201 - PW252 3PW261 - PW268 3PW271 - PW276 3PW278 3PW281 - PW293 3PW296 3PW301 - PW327 3PW401 - PW408 3PW411 - PW418 3PW421 - PW424 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 20 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 21 GroupVariable Number 3PW431 - PW435 3PW441 - PW450 3PW461 - PW467 3PW501 - PW504 3PW511 - PW522 3PW524 - PW550 3PW556 - PW557 3PW561 - PW564 3PW571 - PW576 3PW591 - PW596 3PW611 - PW622 3PW631 - PW637 3PW661 - PW662 3PW681 - PW683 3PW701 - PW702 3PW711 - PW717 3PW741 - PW742 3PW761 3PW771 3PW831 3PW851 - PW856 1PX071 1PX701 2PY001 - PY006 1PY007 - PY008 1PY021 - PY022 1PY031 1PY036 - PY037 1PY046 - PY048 1PY051 - PY053 1PY056 - PY057 1PY101 - PY103 1PY111 - PY113 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 21 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 22 GroupVariable Number 1PY131 - PY135 1PY141 - PY143 1PY151 - PY154 1PY156 - PY157 1PY161 - PY162 1PY166 1PY191 1PY201 1PY221 - PY222 1PY231 1PY241 - PY244 1PY270 - PY275 1PY281 1PY286 2PY301 - PY304 2PY321 - PY323 2PY341 - PY346 2PY361 - PY362 1PY381 1PY401 1PY409 - PY411 1PY421 - PY422 1PY441 1PY451 1PY461 - PY463 1PY591 - PY595 1PY611 - PY612 1PY621 1PY631 1PY651 1PY671 - PY672 1PY721 1PY741 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 22 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 23 2. Spares Affected Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for the recommended use. B. Concurrent Requirements None. C. Reason This service bulletin gives the instructions to inspect, repair, overhaul, and replace the flap track at Wing Buttock Line (WBL) 254. Since 1989, Boeing has more than thirty reports of cracks in the flap track at WBL 254. Cracks were found in the area of the rear spar attachment, in the track webs, and in the upper and lower flanges at the aft end of the track. The cracks in the area of the spar attachment were found at the edge of the hole for the outboard bolt, or between the center bolt hole and the outboard bolt hole, or at the outer edge of the flange adjacent to the outboard bolt. The cracks in the upper and lower flanges were 0.1 to 1.5 inches in length, and the cracks in the aft end of the webs were 0.75 to 7.0 inches in length. In one incident the aft end of a track had cracks through the two lower flanges, through the two webs, and through the fail-safe spacer. The two upper flanges were all that kept the aft end attached to the remaining part of the track. Also, a track was found with cracks through the two upper and two lower flanges, and through the two webs. The fail-safe spacer was all that kept the aft end of this track attached. This track also had a piece broken out in the curved area of the upper outboard flange. Some of the reports also show that tracks were found loose and had corrosion in the area of the rear spar attachment. These tracks that were found loose also had damaged, or missing, anti-fret strips and tapered shims. Initially, the loose tracks were thought to be caused by a weak bond of, or compression damage to, the phenolic anti-fret strip installed in the joint between the track and rear spar. But, subsequent reports showed that the sequence and procedures used during track installation could also be a cause of loose tracks. During installation, when full torque is applied to the forward attach bolt, it can cause the track to move laterally at the rear spar joint. If the track moves laterally at the rear spar joint during the installation procedures, it can put a side load on the inboard aft attach bolt. Then, when the inboard aft attach bolt is tightened to the specified torque value, some of the torque can be absorbed by friction. Subsequently, because of the friction, the torque applied to the bolt is not sufficient to hold the track tight against the rear spar structure. Continued operation with a cracked and/or loose attachment at the rear spar could cause the track to break. A result of a broken track could be the loss of the outboard trailing edge flap, and may preclude continued safe flight and landing of the airplane. The new spares track assemblies have increased upper flange thickness in the attachment area that mates with the wing rear spar, and improved coatings and processes for corrosion protection. The new track for the 737-100/200 also has an improved fail-safe configuration at the forward end that makes it comparable to the 737-300/400/500 track assembly. The inspections given in this service bulletin will find the conditions that make repair or replacement of the flap track necessary. The repairs, scheduled overhauls, correct alignment during installation, and regularly scheduled maintenance will keep tracks in a serviceable condition. There is no terminating action for this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 23 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 24 This service bulletin replaces Service Bulletins 737-57A1082, 737-57A1249, and 737-57A1265. Boeing Service Related Problem (SRP) 737-SRP-57-0131 is related to this service bulletin. Revision 01 is sent to include the data given in Information Notice 737-57A1271 IN 01 and make these changes: – The two notes that read "Some small cracks in the web, that start in the fastener holes, can be repaired with the overhaul instructions given in 737 OHM 57-53-15" are removed from the work instructions. Also, this statement is not added to the Action and Description paragraphs as stated in Information Notice 737-57A1271 IN 01. – Three notes are added to Paragraph 1.E., Compliance. The notes give more data about the overhaul of the flap tracks as related to the initial and repeat inspections. – A statement that shows the relationship between this service bulletin, Service Bulletin 737-57A1082, AD 90-06-02, and Boeing Document D6-38505 is added to Paragraph 1.F., Approval. – Figure 7, Note (d), List Item 3 is corrected to read "inboard attach hole" and a caution is added before List Item 3 to make sure that the inner diameter of the steel bushing is not increased at the inboard attach bolt. – Figure 9, Note (b) is moved to the part number column of Step 9 and the note is changed to add Track Assembly 65C35616-5. Note (d) is added to Step 9 to give part usage data. – Figure 11, added an upper limit for the thermal spray coating dimensions. Added additional coating information to view E-E, and added a new detail view "C". Note (c) is added to Step 2 to show thermal spray coating requirements. Revision 02 is sent to make to following changes: – 1.A. Effectivity: - Added reference to 65C35380-( ) and 65-67158-6 part numbers in the group configuration description. – 1.D. Description: - Added reference to 65C35380-( ) and 65-67158-6 part numbers in the group configuration description. - Added Maintenance zone table. – 1.E. Compliance: - Added statement to remove flap track assemblies with short failsafe bars from service. – 1.K. Publications Affected: - Added damage tolerance statement. – 2.C. Parts Necessary For Each Airplane: - Revised note (c) for spare parts availability. – 3.B. Work Instructions: - Clarified the inspection steps. – Figure 3 and 7: - Clarified notes. – Figure 8: - Corrected fastener grip length for step 11. Revision 3 is sent to incorporate Information Notice 737-57A1271 IN 02. This Information Notice informed operators that sheet 2 of 3 in Figure 1, in revision 2 of this service bulletin should be ignored. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 24 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 25 D. Description Do an initial inspection of the track webs, track flanges, and the track-to-wing attachment at WBL 254. Look for stop-drill repairs and cracks in the track webs. Look for stop-drill repairs, cracks, nicks, corrosion pits, galling, and other signs of damage on the track flanges. Look for corrosion, loose bolts, and a damaged or a missing anti-fret strip and/or tapered shim at the track-to-wing attachment. Remove a track from service if it has a stop-drill repair. If possible, make repairs to the edges of the track flange, but replace the track if cracks are found in the webs. Disassemble the track-to-wing joint and do more inspections if signs of corrosion, loose bolts, or a damaged or missing anti-fret strip or tapered shim are found. If necessary make and install a new anti-fret strip, and/or tapered shim, and remove corrosion and make repairs to the track. Do the procedures to correctly align the track during assembly of the track-to-wing joint. If the track cannot be repaired, install a serviceable flap track assembly. During installation of a serviceable flap assembly, do the procedures to correctly align the track during installation. Do the repeat inspections and schedule the initial, and repeat overhaul, of a flap track at the times given in Paragraph 1.E., Compliance. Flap track assemblies with short fail-safe bars, part number 65-46428-31 and 65-46428-33, must be removed from service if damage is found during an inspection or repair. If damage is not found, these flap tracks with short fail-safe bars must be removed from service at the initial overhaul. NOTE: It will be necessary to keep records of the flap tracks because they can be moved from one airplane to another. NOTE: The steel flap track and the aluminum spacer block are a machined set. During initial assembly, the aluminum spacers are machined to fit the machined slot in the steel tracks. Thus, each assembly must be kept together, as a machined set, during the overhaul procedures. The airplane effectivity is divided in three groups as follows:  Group 1 are 737-100/200 airplanes with 65-46428-() or 65C35380-( ) Flap Track Assemblies. The inspection, overhaul, and replacement instructions given in this service bulletin are applicable to Group 1 airplanes.  Group 2 are 737-200 airplanes with 65-67158-() or 65C35380-( ) Flap Track Assemblies. The inspection and overhaul instructions given in this service bulletin are applicable to Group 2 airplanes. If necessary, these tracks can be replaced with part number 65-67158-6.  Group 3 are 737-300/400/500 airplanes with 65-46428-(), 65C35616-(), 65C35387-(), 65C34812-() or 65C35380-( ) Flap Track Assemblies. The inspection, overhaul, and replacement instructions given in this service bulletin are applicable to Group 3 airplanes. Revision 1 - no more work is necessary on airplanes changed as shown in initial release of this service bulletin. Revision 2 - No more work is necessary on airplanes changed in accordance with the original issue or Revision 1 of this service bulletin. Revision 3 - No more work is necessary on airplanes changed in accordance with Revision 2 of this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 25 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 26 Group 1-2: Affected Maintenance Zones ZoneModel 3-7, 4-7737-100, 737-200, 737-200C Group 3: Affected Maintenance Zones ZoneModel 307, 407737-300, 737-400, 737-500 E. Compliance The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Federal Aviation Administration Airworthiness Directive (AD) 78-13-07, Amendment 39-3253; AD 2000-25-07, Amendment 39-1204; AD 2002-05-07, Amendment 39-12675; and AD 90-06-02, Amendment 39-6489 are related to this service bulletin. Boeing recommends the inspection and overhaul of the flap track installed at Left WBL 254, and Right WBL 254, as follows.  Initial Inspection. Perform the initial inspection of the flap track, using the instructions in this service bulletin, prior to the later of the times specified below:  15,000 flight cycles or 8 years since new or overhauled, whichever occurs first, or  180 days after the issue date on this service bulletin  Within 24 months of the last inspection performed in accordance with Part I of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000. NOTE: Overhaul of a flap track, with the overhaul instructions given in this service bulletin, can satisfy the initial inspection. Flap track assemblies with short failsafe bars, part number 65-46428-31 and 65-46428-33 must be removed from service during inspection or repair. NOTE: Tracks overhauled to satisfy the initial inspection must be scheduled for the repeat inspections and repeat overhauls.  Initial Overhaul. Do an initial overhaul of the flap track, using the instructions in this service bulletin, within 10,000 flight cycles or 4 years, whichever occurs first, of the Initial Inspection.  Repeat Inspections. Perform repeat inspections of the flap track within 10,000 flight cycles or 4 years, whichever occurs first, of the overhaul using the instructions in this service bulletin. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 26 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 27 NOTE: Overhaul of a flap track, with the overhaul instructions given in this service bulletin, can satisfy a repeat inspection.  Repeat Overhauls. Repeat the overhaul of the flap track, using the instructions in this service bulletin, at intervals not to exceed 20,000 flight cycles or 8 years, whichever occurs first. 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. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves these actions: 1. Performance of all requirements defined in "WORK INSTRUCTIONS, INSPECTION - TRACK WEB AND FLANGES" constitutes, for the inboard track only, an alternative method of compliance to the inspection intervals, methods and repair required by paragraphs A, B, C, and D of Airworthiness Directive 78-13-07. All other provisions of Airworthiness Directive 78-13-07, not specifically referenced in this statement, remain fully effective and must be complied with. The requirements for the outboard track defined by Airworthiness Directive 78-13-07, remain in effect and are not affected by the alternative method of compliance statement, described above. 2. Performance of detail visual inspection and requirements defined in "WORK INSTRUCTIONS, INSPECTION - TRACK WEB AND FLANGES" constitutes an alternative method of compliance to the inspection methods and corrective action required by paragraphs (a) and (b) of Airworthiness Directive 2000-25-07. All other provisions of Airworthiness Directive 2000-25-07, not specifically referenced in this statement, remain fully effective and must be complied with. 3. Performance of inspections defined in "WORK INSTRUCTIONS, INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED" constitutes an alternative method of compliance to the inspection methods required by paragraphs (a)(1), (a)(2) and (d) of Airworthiness Directive 2002-05-07. All other provisions of Airworthiness Directive 2002-05-07, not specifically referenced in this statement, remain fully effective and must be complied with. 4. Performance of actions defined in "WORK INSTRUCTIONS, INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED" constitutes an alternative method of compliance to the rework required by paragraph (c) of Airworthiness Directive 2002-05-07. all other provisions of Airworthiness Directive 2002-05-07, not specifically referenced in this statement, remain fully effective and must be complied with. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 27 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 28 5. The Manager of the FAA Seattle Aircraft Certification office approves the overhaul of the outboard flap inboard track per the Accomplishment Instructions in Service Bulletin 737-57A1271, Revision 3, as an Alternative Method of Compliance to the modification requirements of Paragraph A of AD 90-06-02 for SB 737-57A1082 only. All provisions of AD 90-06-02 not specifically referenced in the above statement, including the modification threshold, remain fully applicable and must be complied with. G. Manpower The table below shows 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 examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. Elapsed HoursTask-HoursNumber of Per- sons Task 4.024.0 (a)6Open Access 3.06.02Inspect (b)(b)(b)Repair 8.016.04Replace 5.030.0 (a)6Close Access 3.06.02Test 23.082.0TOTAL FOR EACH AIRPLANE The estimate shows the man hours necessary for the access procedures to do the inspection with the track-to-wing attachment disassembled. (a) No estimate given for the repair procedures.(b) H. Weight and Balance Changes None. I. Electrical Load Data Not changed. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 28 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 29 J. References 1. Existing Data: a. Engineering Change Memo PRR 35005-238RS b. Service Related Problem (SRP) 737-SRP-57-0131 c. 737-100/200 Maintenance Manual (AMM) Subject 12-20-0, 27-51-72, 27-51-111, 27-51-121, 27-51-151, 27-51-281 d. 737-300/400/500 Maintenance Manual (AMM) Subject 27-51-49. 27-51-52 e. 737 Nondestructive Test (NDT) Manual 737, Part 4, Subject 57-50-01 f. 737 Nondestructive Test (NDT) Manual 737, Part 6, Subject 57-50-01 g. 737 Nondestructive Test (NDT) Manual 737, Part 6, Subject 57-50-06 h. 737 Nondestructive Test (NDT) Manual 737, Part 6, Subject 51-00-00, Figure 19. i. 737 Nondestructive Test (NDT) Manual 737, Part 6, Subject 51-00-00, Figure 24. j. Overhaul Manual 57-53-15 k. 737 Structural Repair Manual (SRM) Chapter 51 l. Boeing Standard Overhaul Practices Manual (BSOPM) 20-10-01, 20-10-03. 20-30-02, 20-42-05, 20-43-03 m. Boeing Service Bulletin 737-57A1082 n. Boeing Service Bulletin 737-57-1203 o. Boeing Service Bulletin 737-57A1249 p. Boeing Service Bulletin 737-57A1265 q. FAA Airworthiness Directive 78-13-07, Amendment 39-3253 r. FAA Airworthiness Directive 90-06-02, Amendment 39-6489 s. FAA Airworthiness Directive 2000-25-07, Amendment 39-12041 t. FAA Airworthiness Directive 2002-05-07, Amendment 39-12675 u. Boeing Document D6-38505 v. Boeing Parts Standards Document D-590 w. Boeing Drawing 65-88700 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 29 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 30 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number Flap Track Installation - Inbd And Outbd Flap65-46429 Track Assy - Outboard Flap65-46428 Track Assy - Outboard Flap65C34812 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. K. Publications Affected 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS but no new DTIs are necessary. L. Interchangeability and Intermixability of Parts Refer to Paragraph 2.C., Parts Necessary For Each Airplane, for interchangeability and intermixability information. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 30 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 31 2. MATERIAL INFORMATION A. Material - Price and Availability The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary For Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. B. Industry Support Information Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. C. Parts Necessary For Each Airplane 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: NOTE: Quantity is for the replacement of one flap track. NotesExisting Part NumberNameQTYPart Number / Specification (b)(a)Flap Track Assy (Group 1 Airplanes)165-46428-36 (c)65-67158-2, or -3, or -6Flap Track Assy (Group 2 Airplanes)-- (e)(d)Flap Track Assy (Group 3 Airplanes)165C34812-8 (j)66-23210-6Sleeve166-23210-1 (h) (j)-Bolt1BACB30LE7HK26 (i) (j)-Bolt1BACB30LE8HK32 (i) (j)-Bolt1BACB30LE8HK31 (j)-Bolt1BACB30LT7DU27 (j)-Bolt1BACB30LT7DU17 (j)-Nut1BACN10HR7CD (j)-Nut1BACN10JD107 (j)-Washer1BACW10BN7SC (j)-Washer1BACW10BP7C (j)-Washer1BACW10BP7CD (j)-Washer1BACW10BP7P (k)-Washer, Torque-Indicating1BACW10DN8 (j)-Barrel Nut1NAS577B8A BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 31 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 32 NotesExisting Part NumberNameQTYPart Number / Specification (j)-Retainer1NAS578-8A (j)-Washer-NAS1149F0716P (j)-Washer-NAS1149F0732P (j)-Washer-NAS1149F0763P (i) (j)-Washer-NAS1149F0816P (i) (j)-Washer-NAS1149F0832P -Lockwire-NASM20995C32 -Cotter Pin1MS24665-285 -Sealant1 ptBMS 5-95 -Primer8 ozBMS 10-11, Type I Refer to BSOPM 20-43-03 -Chemical Conversion Coating8 ozType 2, Class A -Corrosion Preventive Compound8 ozMIL-C-11796, Class 3 (l)-Thermal Spray Powder-BMS 10-67, Type 1, Class 2 or 4 (l)-Retaining Compound-Loctite 262 or MIL- S-46163, Type II, Grade O (l)-Adhesion Promoter-Locquic Primer N 7649 65-46428-2, or -3, or -5, or -7, or -9, or -11, or -15, or -17, or -19, or -21, or -23, or -25, or-27, or -33, or -35. (a) You can use the existing part 65-46428-2, or -3, or -5, or -7, or -9, or -11, or -15, or -17, or -19, or -21, or -23, or -25, or-27, or -35, overhauled with the instructions in this service bulletin to replace the new or changed part. (b) You cannot use the existing part 65-46428-33 to replace the new or changed part. Boeing recommends that you remove the 65-46428-33 from service as given in Service Bulletin 737-57-1203. If you use the existing part 65-46428-2, or -3, or -5, or -7, or -9, or -11, or -15, or -17, or -19, or -21, or -23, or -25, or-27, or -35, you reduce the effect of the change given in this service bulletin. The existing track assembly does not have the fail safe capability of the new spares track assembly. The new spare flap track assembly for Group 2 airplanes is 65-67158-6. See 737-100/-200 AMM 27- 51-151 for removal and installation of these flap track assemblies. (c) 65-46428-31, or 65C35387-4, or 65C35616-5, or 65C34812-3, or -4, or -6(d) You can use the existing part 65C35616-5, or 65C35387-4, or 65C34812-3, or -4, or -6, overhauled with the instructions in this service bulletin to replace the new or changed part. (e) You cannot use the existing part 65-46428-31 to replace the new or changed part. Boeing recommends that you remove the 65-46428-31 from service as given in Service Bulletin 737-57-1203. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 32 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 33 See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data.(f) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners.(g) It is possible, because of shim thickness, that a bolt one grip length shorter or longer can be necessary for installation of the new spares track assembly. One Washer NAS1149F0716P, or NAS1149F0732, can be used to adjust the grip length of the bolt. See Figures 8 and 9. (h) It is possible, because of shim thickness, that a bolt one grip length shorter or longer can be necessary for installation of the new spares track assembly. One Washer NAS1149F0816P, or NAS1149F0832P, can be used to adjust the grip length of the bolt. See Figures 8 and 9. (i) If installed on the configuration of your airplane: The removed part can be serviceable and satisfactory for installation of the new spares flap track assembly. See Figures 8 and 9. (j) A new torque-indicating washer is necessary if the wing-to-track attachment is disassembled during the inspection procedures, and for the track alignment and installation procedures given in Figures 7, 8, and 9. (k) The retaining compound and adhesion promoter are necessary for the overhaul of a flap track. The application of the thermal spray powder (Tungsten-Carbide-Cobalt) is optional during the overhaul procedures, unless the track had Tungsten-Carbide-Cobalt applied during manufacture. Tracks that had Tungsten-Carbide-Cobalt applied during manufacture, must also have the compound applied during the overhaul procedures. See Figure 11. (l) 3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 33 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 34 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 34 of 77 BOEING SERVICE BULLETIN 737-57A1271 BLANK PAGE ### Page 35 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 are in Structural Repair Manual 737 (SRM) 51 – Torque limits to tighten nuts and bolts are in 737 SRM 51 4. Use the approved fastener and process material substitutions in accordance with 737 SRM 51. Alternate fasteners are listed in 737 SRM 51. 5. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures, and SWPM 20-10-19 for the wire separation requirements, as accepted procedures. 6. If the length of any fastener specified in this service bulletin does not meet the installation standards in 737 SRM 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards in 737 SRM 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 7. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate access procedures may be required. 8. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 35 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 36 9. 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. 10. 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. 11. 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. 12. 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. 13. 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. The removed part can be discarded if a new or serviceable part is installed. 14. 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. 15. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-' (dash) part number. Boeing Drawing 005W0900 contains more data. B. WORK INSTRUCTIONS INSPECTION - GROUP 1 AND GROUP 2 AIRPLANES - 737-100/200/200C 1. Remove the forward fairing from Flap Track Position 2 (Position 7 opposite). NOTE: Position 2 is equivalent to Left WBL 254 and Position 7 is equivalent to Right WBL 254. 2. Refer to 737-100/200 AMM 27-51-121 and remove the center and aft fairings from Position 2 (Position 7 opposite). NOTE: When you disconnect the push rod from the aft flap, install a support to sufficiently hold the aft flap in a stable position during the inspection procedures. During the inspection procedures it will be necessary to extend and retract the flaps to get access to all areas of the flap track. 3. INSPECTION - TRACK WEBS AND FLANGES. Do a visual and eddy current inspection of the flap track web and flanges as shown in Figure 1. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 36 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 37 a. If damage is found in the web or on the upper and/or lower flanges of the track: (1) Make repairs as given in 737 OHM 57-53-15. (2) If the damage cannot be repaired as given in OHM 57-53-15: Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the flanges of the track. Go to Step 5 for instructions for removal and installation. b. If an existing stop-drill repair is found on the upper and/or lower flanges of the track: (1) Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the flanges. Go to Step 5 for instructions for removal and installation. c. If the web has an existing stop-drill repair: (1) Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the web. Go to Step 5 for instructions for removal and installation. d. If you do not find damage in the flanges and/or the web, or you made repairs as given in 737 OHM 57-53-15, continue with the detail visual, ultrasonic, and eddy current inspections given in Step 4, below. e. If a flap track assembly with a short failsafe bar, part number 65-46428-31 or 65-46428-33, is found, it must be removed from service during inspection or repair. 4. INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED. Using Figure 2, do a detail visual inspection, ultrasonic inspection, and an eddy current inspection in the area where the flap track is attached to the wing rear spar. a. If the track is loose at the attachment to the wing rear spar: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. b. If there are signs of damage, or corrosion, to the tapered shim and/or anti-fret strip: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. c. If the ultrasonic or eddy current inspection shows an indication of a crack: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. d. If no signs of cracks, damage, corrosion, or a loose track are found: Schedule the overhaul of the flap track at the flight cycle or in-service time given in Paragraph 1. E., Compliance 5. INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED. a. Refer to 737-100/200 AMM 27-51-72 and remove the trailing edge flaps. b. Refer to 737-100/200 AMM 27-51-281 and remove the flap transmission. c. Refer to 737-100/200 AMM 27-51-111 and remove the fore-flap sequencing carriage from the track. d. Remove the bolts, lower the aft end of the track, and do the inspections given in Figure 3. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 37 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 38 (1) If the anti-fret strip is discarded during the inspection: Make and install a new anti-fret strip as shown in Figure 4. Make the shop aid, shown in Figure 10, to get a satisfactory installation of the new anti-fret strip. (2) If the tapered shim is discarded during the inspection: Make and install a new tapered shim as shown in Figure 5. Make the shop aid, shown in Figure 10, to get a satisfactory installation of the new tapered shim. (3) If the steel bushing is discarded during the inspection: Make and install a new bushing as shown in Figure 6. (4) If corrosion is found on the mating surface, and/or in the bolt holes: Remove the corrosion as given in Figure 6. (5) If corrosion is found during the inspection along the outboard edge of the track flange adjacent to the outboard bolt: Make repairs as shown in the rework tables of Figure 6. If damage is too large and cannot be removed within the limits of the rework tables: Replace the flap track with a serviceable flap track. (6) If damage is found with the eddy current inspection of the outboard hole: Remove the damage as given in the eddy current inspection procedures, but make sure the hole remains in the limits given in Figure 6. If damage is too large and cannot be removed during rework in accordance with Figure 6: Replace the flap track with a serviceable flap track. e. Align and install the track as shown in Figure 7. f. Refer to 737-100/200 AMM 27-51-111 and install the fore-flap sequencing carriage. g. Refer to 737-100/200 AMM 27-51-281 and install the flap transmission. h. Refer to 737-100/200 AMM 27-51-72 and install the trailing edge flaps. 6. Refer to 737-100/200 AMM 12-20-0 and lubricate the flap track. 7. Refer to 737-100/200 AMM 27-51-121 and install the center and aft fairings at Position 2 (Position 7 opposite). 8. Install the forward fairing at Position 2 (Position 7 opposite). 9. Put the airplane back to a serviceable condition. INSPECTION - GROUP 3 AIRPLANES - 737-300/400/500 1. Remove the forward fairing from Flap Track Position 2 (Position 7 opposite). 2. Refer to 737-300/400/500 AMM 27-51-52 and remove the center and aft fairing from Flap Track Position 2 (Position 7 opposite). BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 38 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 39 NOTE: When you disconnect the push rod from the aft flap, install a support to sufficiently hold the aft flap in a stable position during the inspection procedures. During the inspection procedures it will be necessary to extend and retract the flaps to get access to all areas of the flap track. 3. INSPECTION - TRACK WEBS AND FLANGES. Do a visual and eddy current inspection of the flap track web and flanges as shown in Figure 1. a. If damage is found in the web or on the upper and/or lower flanges of the track: (1) Make repairs as given in 737 OHM 57-53-15. (2) If the damage cannot be repaired as given in OHM 57-53-15: Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the flanges of the track. Go to Step 5 for instructions for removal and installation. b. If an existing stop-drill repair is found on the upper and/or lower flanges of the track: (1) Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the flanges. Go to Step 5 for instructions for removal and installation. c. If the web has an existing stop-drill repair: (1) Replace the flap track with a serviceable flap track. Do not stop-drill cracks in the web. Go to Step 5 for instructions for removal and installation. d. If you do not find damage in the flanges and/or the web, or you made repairs as given in 737 OHM 57-53-15: Continue with the detail visual, ultrasonic, and eddy current inspections given in Step 4, below. e. If a flap track assembly with a short failsafe bar, part number 65-46428-31 or 65-46428-33, is found, it must be removed from service during inspection or repair. 4. INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED. Using Figure 2, do a detail visual inspection, and an ultrasonic and eddy current inspection in the area where the flap track is attached to the wing rear spar. a. If the track is loose at the attachment to the wing rear spar: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. b. If there are signs of damage, or corrosion, to the tapered shim and/or anti-fret strip: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. c. If the ultrasonic or eddy current inspection shows an indication of a crack: Do the inspection with the track-to-wing attachment disassembled as shown in Step 5, below. d. If no signs of cracks, damage, corrosion, or a loose track are found: Schedule the overhaul of the flap track at the flight cycle or in-service time given in Paragraph 1. E., Compliance. e. If a flap track assembly with a short failsafe bar, part number 65-46428-31 or 65-46428-33, is found, it must be removed from service during inspection or repair. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 39 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 40 5. INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED. a. Refer to 737-300/400/500 AMM 27-51-34 and remove the trailing edge flaps. b. Refer to 737-300/400/500 AMM 27-51-71 and remove the flap transmission. c. Refer to 737-300/400/500 AMM 27-51-47 and remove the fore-flap sequencing carriage from the track. d. Remove the bolts, lower the aft end of the track, and do the inspections given in Figure 3. (1) If the anti-fret strip is discarded during the inspection: Make and install a new anti-fret strip as shown in Figure 4. Make the shop aid, shown in Figure 10, to get a satisfactory installation of the new anti-fret strip. (2) If the tapered shim is discarded during the inspection: Make and install a new tapered shim as shown in Figure 5. Make the shop aid, shown in Figure 10, to get a satisfactory installation of the new tapered shim. (3) If the steel bushing is discarded during the inspection: Make and install a new bushing as shown in Figure 6. (4) If corrosion is found on the mating surface, and/or in the bolt holes: Remove the corrosion as given in Figure 6. (5) If corrosion is found during the inspection along the outboard edge of the track flange adjacent to the outboard bolt: Make repairs as shown in the rework tables of Figure 6. If damage is too large and cannot be removed within the limits of the rework tables: Replace the flap track with a serviceable flap track. (6) If damage is found with the eddy current inspection of the outboard hole: Remove the damage as given in the eddy current inspection procedures, but make sure the hole remains in the limits given in Figure 6. If damage is too large and cannot be removed during the rework in accordance with Figure 6: Replace the flap track with a serviceable flap track. e. Align and install the track as shown in Figure 7. f. Refer to 737-300/400/500 AMM 27-51-47 and install the fore-flap sequencing carriage. g. Refer to 737-300/400/500 AMM 27-51-71 and install the flap transmission. h. Refer to 737-300/400/500 AMM 27-51-34 and install the trailing edge flaps. 6. Refer to 737-300/400/500 AMM 12-20-0 and lubricate the flap track. 7. Refer to 737-300/400/500 AMM 27-51-52 and install the center and aft fairings at Position 2 (Position 7 opposite). 8. Install the forward fairing at Position 2 (Position 7 opposite). BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 40 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 41 9. Put the airplane back to a serviceable condition. OVERHAUL - GROUPS 1, 2, AND 3, AIRPLANES - 737-100/200/200C/300/400/500 1. At the flight cycle or in- service time given in Paragraph 1. E.,Compliance: Refer to 737-100/200 AMM 27-51-151 and remove the flap track from the wing at Position 2 (Position 7 opposite). Refer to 737-300/400/500 AMM 27-51-49 and remove the flap track from the wing at Position 2 (Position 7 opposite). 2. Do an overhaul of the flap track as given in 737 OHM 57-53-15 and Figure 11. 3. Install an overhauled flap track at Position 2 (Position 7 opposite) as given in 737-100/200 AMM 27-51-151. Align the flap track during installation as shown in Figure 7. Install an overhauled flap track at Position 2 (Position 7 opposite) as given in 737-300/400/500 AMM 27-51-49. Align the flap track during installation as shown in Figure 7. 4. Schedule the repeat inspections and the repeat overhaul of the flap track at the flight cycles or times given in Paragraph 1. E., Compliance. 5. Put the airplane back to a serviceable condition. REPLACEMENT - GROUP 1 AIRPLANES 1. Refer to 737-100/200 AMM 27-51-151 and remove the flap track assembly. During removal, discard the parts shown in Figure 8. 2. Refer to 737-100/200 AMM 27-51-151 and install the new track assembly. During installation, do the alignment procedures given in Figure 7 and install the parts shown in Figure 8. 3. Put the airplane back to a serviceable condition. REPLACEMENT - GROUP 2 AIRPLANES 1. Replace the track assembly with an identical spares track assembly. REPLACEMENT - GROUP 3 AIRPLANES - 737-300/400/500 1. Refer to 737-300/400/500 AMM 27-51-49 and remove the flap track assembly. During removal, discard the parts shown in Figure 9. 2. Refer to 737-300/400/500 AMM 27-51-49 and install the new spares track assembly. During installation, do the alignment procedures given in Figure 7 and install the parts shown in Figure 9. 3. Put the airplane back to a serviceable condition. BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3: February 13, 2012 41 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 42 (OCR) BOEING SERVICE BULLETIN 737-57A1271 WBL 254 SEE 608066650600008 234 VISUAL INSPECTION AREA - WEBS AND UPPER/LOWER FLANGES - BOTH SIDES OF TRACK FWDE Br - PIECE BROKEN OFF TYPICAL WEB CRACK FWD C B A-A (EXAMPLE - CRACKS AND DAMAGE) TYPICAL FLANGE CRACK PIECE BROKEN OFF The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 1: INSPECTION - TRACK WEBS AND FLANGES (SHEET 1 OF 2) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 42 of 77 ### Page 43 WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF ALL CONTROL SURFACES BEFORE YOU SUPPLY HYDRAULIC POWER. CONTROL SURFACES CAN MOVE QUICKLY WHEN YOU SUPPLY HYDRAULIC POWER. THIS CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT. WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE LEADING EDGE AND TRAILING EDGE FLAPS AND FLAP DRIVE MECHANISMS BEFORE YOU MOVE THE FLAP CONTROL HANDLE. AN ACCIDENTAL FLAP MOVEMENT CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. NOTESQTYPART NUMBERNAMETASKSTEP (a)--Hydraulic PowerSupply1 --FlapsExtend/Retract --Hydraulic PowerRemove (b)1-Flap TrackClean2 (c)--Track FlangesInspect3 (d)--Track WebsInspect4 (e)--Eddy Current InspectionDo5 Refer to 737-100/200 AMM 27-51-0 and supply hydraulic power. Group 3: Refer to 737-300/400/500 AMM 27-51-00 and supply hydraulic power. As necessary, extend and retract the flaps during the in- spection procedures to get access to all areas of the flap track. (a) Warning: MAKE SURE TO REMOVE HYDRAULIC POWER BEFORE PERSONS GO INTO THE IN- SPECTION AREA. AN ACCIDENTAL FLAP MOVEMENT CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. Remove loose paint, sealant, corrosion inhibiting compounds, dirt and grease from the flanges and webs of the track. Removal of the finish is not necessary, unless signs of cracks or corrosion are found during the subsequent inspections. (b) Caution: DO NOT PRESSURE WASH THE FLAP TRACK. WATER OR SOLVENTS UNDER HIGH PRESSURE CAN GET UNDER THE FASTENER HEADS AND BETWEEN THE WEBS AND SPACER BAR. A RESULT CAN BE UNWANTED CORROSION AND CRACKS. Do a detailed visual inspection along the full length of the upper and lower flanges of the flap track. Look for stop-drill repairs, cracks, nicks, corrosion pits, galling, pieces broken off, or other signs of damage. Give special attention to the edges of the flanges. Reject a track that shows these signs of damage, or has existing stop-drill repairs. (c) Do a detailed visual inspection along the full length of the track webs. Look for stop-drill repairs, cracks, or other signs of damage. During the inspection, give special attention to the area adjacent to the fas- tener countersinks in the webs. (d) Reject tracks that have existing stop-drill repairs, and/or cracks in the web. No repair instructions are given in this service bulletin for web cracks. Do the eddy current inspection given in 737 NDT Part 6, 57-50-06. Reject a track that shows indications of cracks. (e) FIGURE 1: INSPECTION - TRACK WEBS AND FLANGES (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 43 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 44 (OCR) BOEING SERVICE BULLETIN 737-57A1271 WBL 254 INBOARD AFT TRACK ATTACH BOLT SUPPORT SEE OUTBOARD FITTING ATTACH BOLT LOWER WING SKIN 1X26 AFT TRACK 126 SUPPORT 3 ANTI-FRET FITTING STRIP ANTI-FRET STRIP TAPERED SHIM 126 FLAP TRACK TAPERED SHIM WING SKIN SEE INBD FLAP TRACK (WBL 254) FWD INBD A-A AFT TRACK OUTBOARD SUPPORT FITTING ATTACH BOLT REAR SPAR WEB ANTI-FRET STRIP REAR SPAR CHORD 26 LOWER TAPERED SHIM WING SKIN 12)(6 FWDY FLAP TRACK (WBL 254) B—B The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 2: INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED (SHEET 1 OF 2) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 44 of 77 ### Page 45 NOTESQTYPART NUMBERNAMETASKSTEP Remove sealant sufficient- ly to get a clear view of the outer edges of the ta- pered shim and anti-fret strip. --SealantRemove1 (a)--Tapered ShimInspect2 --Anti-Fret Strip (b)--Track AttachmentInspect3 (c)--Track AttachmentInspect4 (d)--Track AttachmentInspect5 (e)-BMS 5-95SealantApply6 Do a detailed visual inspection of the tapered shim and anti-fret strip. Look for signs of movement be- tween the components. Look to make sure the anti-fret strip is installed. Look for corrosion. (a) Do a detailed visual inspection of the area where the track is attached to the wing rear spar. Use manual force, up to 150 pounds, and try to move the track from the installed position. Look for signs of movement, cracks, and corrosion. (b) Do the eddy current inspection given in 737 NDT Part 6, 57-50-01. Do this inspection to find cracks in the outboard edge of the track adjacent to the outboard attach bolt. (c) Do the ultrasonic inspection given in 737 NDT Part 4, 57-50-01. Do this inspection to find cracks in the inner edge of the track adjacent to the outboard attach bolt. (d) Apply around the outer edges of the tapered shim and anti-fret strip. Do not apply the sealant at this time if disassembly of the track-to-wing attachment is made necessary as given in the Paragraph 3.B., Work Instructions. (e) FIGURE 2: INSPECTION - WITH TRACK-TO-WING ATTACHMENT ASSEMBLED (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 45 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 46 (OCR) BOEING SERVICE BULLETIN 737-57A1271 SEE FORWARD ATTACH BOLT SHIM THICKNESS DECAL BUSHINGS REAR AFT TRACK SPAR SUPPORT WEB FITTING (6) ANTI-FRET STRIP REAR SPAR CHORD 1 TAPERED SHIM LOWER WING TRACK INSPECTION SKIN AREA FWDE • INBD BARREL NUT WASHER AND RETAINER NUT WBL 254 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 3: INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED (SHEET 1 OF 2) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 46 of 77 ### Page 47 NOTESQTYPART NUMBERNAMETASKSTEP 1-Cotter PinRemove1 1-NutLoosen 1-BoltRemove/Keep2 2-Washer 1-Nut 1-BoltRemove/Keep3 1-WasherRemove/Discard4 Put a support below the track to hold it in position during the inspection pro- cedures. 1-TrackLower5 (a)1-Anti-Fret StripInspect6 (b)1-Tapered ShimInspect7 (c)1-Track AttachmentInspect8 (d)1-BushingInspect9 (e)1-Track FlangeInspect10 (f)2-HoleInspect11 Do a detailed visual inspection of the anti-fret strip. Look for signs that show the strip is loose or dam- aged. Discard a strip if it is made from phenolic material, or if it is loose, or if it is damaged. (a) Do a detailed visual inspection of the tapered shim. Discard a shim if it is damaged or shows signs of corrosion. Discard a shim if it is less than 1.70 inches wide as measured normal to the aft edge of the shim. Discard a shim if it is made from laminated material. (b) Do a detailed visual inspection of the track in the area where it mates against the wing skin. Look for corrosion on the surface and corrosion in the bolt holes. Rework/overhaul a track if it shows signs of corrosion. (c) If corrosion is found in the area where the track mates against the wing skin, do a detailed visual in- spection of the bushing. Discard a bushing if there are signs of corrosion between the outer wall and track. (d) Refer to 737 NDT Part 6, 51-00-00, Figure 24 and do an eddy current inspection on the upper surface of the track flange adjacent to the inboard and outboard bolt holes. Set the eddy current instrument frequency setting to 50 KHz to prevent false crack indications caused by scratches in the cadmium plating. Repair or replace a track that shows an indication of a crack. (e) As an alternative to the eddy current inspection, you can do a magnetic particle inspection as given in BSOPM 20-20-01. Refer to 737 NDT Part 6, 51-00-00, Figure 19 and do an eddy current inspection of the inboard and outboard bolt holes. Repair or replace a track that shows an indication of a crack. As an alternative to the eddy current inspection, you can do a magnetic particle inspection as given in BSOPM 20-20-01. (f) FIGURE 3: INSPECTION - WITH TRACK-TO-WING ATTACHMENT DISASSEMBLED (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 47 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 48 (OCR) BOEING SERVICE BULLETIN 737-57A1271 (8) TEMPORARY FASTENERS WASHERS REAR SPAR AFT TRACK WEB SUPPORT FITTING REAR SPAR CHORD ANTI-FRET STRIP SEE A LOWER ( >5 PRESSURE PLATE FWD WING DINBD SKIN WASHER, NUT WBL 254 2.00 0.73 ) ANTI-FRET STRIP WBL 254 / AFT EDGE 0.55 0.53 DIA. HOLE 4.28 • 54 0.70 -1.61→ 0.49 - DIA. HOLE 0.4/ ANTI-FRET STRIP FABRICATION The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 4: REPLACEMENT - ANTI-FRET STRIP (SHEET 1 OF 2) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 48 of 77 ### Page 49 NOTESQTYPART NUMBERNAMETASKSTEP (a)169-50772-( )Anti-Fret StripRemove1 --ThicknessMeasure (b)1-Anti-Fret StripMake2 Apply to all surfaces. Re- fer to BSOPM 20-43-03. -Type 2, Class AChemical Conversion Coating Apply one layer to all surfaces.-BMS 10-11, Type IPrimer (c)--SurfaceClean3 Apply to all bare alu- minum. Refer to BSOPM 20-43-03. -Type 2, Class AChemical Conversion Coating Apply Two layers.-BMS 10-11, Type IPrimer To mating surface of new anti-fret strip. -BMS 5-95SealantApply4 1-Anti-Fret StripInstall 1-Pressure PlateInstall5 2-Temporary FastenersInstall6 (d)--TorqueApply7 2-Temporary FastenersRemove8 1-Pressure Plate Apply a bead around the edges of the strip. -BMS 5-95SealantApply9 Remove the damaged anti-fret strip and measure the thickness. The new replacement strip must have the same thickness as the removed strip. (a) Make from 7075-T6 Aluminum Alloy Sheet, AMS-QQ-A-250/12.(b) Clean and remove all signs of enamel paint from the wing lower surface in the wing-to-track attachment area. Refer to BSOPM 20-30-02. (c) Apply 360-420 inch-pound. Give the sealant sufficient time to cure before you continue with the subse- quent step. (d) FIGURE 4: REPLACEMENT - ANTI-FRET STRIP (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 49 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 50 (OCR) BOEING SERVICE BULLETIN 737-57A1271 8 69 TEMPORARY FASTENERS WASHERS F PRESSURE PLATE FWDA 100 TAPERED SHIM DINBD SEE •STEEL FLAP TRACK BUSHING FLAP TRACK 3 WASHER, BARREL NUT NUT 7 (OR EQUIVALENT) WBL 254 2.00 - 0.73 TAPERED SHIM WBL 254 • AFT EDGE 0.55 0.53 DIA. HOLE 4.28 0.70 TAPERED SHIM FABRICATION -1.61- 0.47 DIA. HOLE N85428 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 5: REPLACEMENT - TAPERED SHIM (SHEET 1 OF 2) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 50 of 77 ### Page 51 NOTESQTYPART NUMBERNAMETASKSTEP (a)165-46429-( ), 69- 50772-( ) or 69- 77633 Tapered ShimRemove1 --ThicknessMeasure (b)1-Tapered ShimMake2 Apply to all surfaces. Re- fer to BSOP 20-43-03. -Type 2, Class AChemical Conversion Coating Apply one layer to all surfaces.-BMS 10-11, Type IPrimer (c)--SurfaceClean3 Two layers.-BMS 10-11, Type IPrimer To mating surface of new tapered shim. -BMS 5-95SealantApply4 1-Tapered ShimInstall 1-Pressure PlateInstall5 2-Temporary FastenersInstall6 (e)2-Self-Aligning Washer 360-420 inch-pound.--TorqueApply7 (d)--TorqueApply8 2-Temporary FastenersRemove9 1-Pressure Plate Apply a bead around the edges of the shim. -BMS 5-95SealantApply10 Remove the rejected shim and measure the thickness. The new replacement shim must have the same thickness as the removed shim, unless corrosion was removed from the upper surface of the track. If corrosion was removed from the track, increase the thickness of the new shim to adjust for the change in the thickness of the track. If you do not know the correct thickness of the new shim, refer to 737-100/200 AMM 27-51-151 for Group 1 and Group 2 Airplanes, and 737-300/400/500 AMM 27- 51-49 for Group 3 Airplanes. (a) Make from 2024-T351 Aluminum Alloy Plate, or Sheet, AMS-QQ-A-250/12. The thickness at all points along the aft edge of the shim must not be less than 0.03 inches. (b) Clean and remove all signs of enamel paint from the mating surface of the track. Refer to BSOPM 20- 30-02. (c) Apply 400-460 inch-pounds. Give the sealant sufficient time to cure before you continue with the sub- sequent step. (d) The two holes are not perpendicular to the surfaces of the tapered shim. To get a satisfactory pressure during the torque procedure, use self-aligning washers. (e) FIGURE 5: REPLACEMENT - TAPERED SHIM (SHEET 2 OF 2) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 51 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 52 (OCR) BOEING SERVICE BULLETIN 737-57A1271 7 0.003 (CROSS HATCHED AREA SEE 0000 FLAP TRACK (WBL 254) REPAIR AREA FWD > B > INBD A-A t, (OUTBOARD SIDE), t¿ (OUTBOARD SIDE), tz (INBOARD SIDE) t4 INBOARD SIDE) FWD < FLAP TRACK (WBL 254) B-B N85479 OUTBOARD SIDE SHOWN, INBOARD SIDE SIMILAR FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT (SHEET 1 OF 5) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 52 of 77/ ### Page 53 (OCR) BOEING SERVICE BULLETIN 737-57A1271 CHAMFER O.D. BOTH ENDS 0.003 X 45 DEGREES 0.013 CHAMFER I.D. BOTH ENDS 0.013 x 45 DEGREES 0.003 349 STEEL BUSHING REPAIR SEE (B AREA 0.5015 0.400 0.5005 0.395 FWD. - O.D.- WBL 254 B REPAIR BUSHING N85528 FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT (SHEET 2 OF 5) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 53 of 77 ### Page 54 Rework Table 1 - Flap Track 65-46427-4 MAXIMUM ALLOWABLE HOLE DIAM- ETERS MINIMUM ALLOWABLE DIMENSIONS d3d2d1WT4 (a)T3 (a)T2 (a)T1 (a) 0.58350.68550.58354.2700.3800.2350.3800.235 Rework Table 2 - Flap Tracks 65-46427-5/-7/-11/-13/-17/-21/-23/-25/-27/-29/-31/-44/-46 & 65C35380-2 MAXIMUM ALLOWABLE HOLE DIAM- ETERS MINIMUM ALLOWABLE DIMENSIONS d3d2d1WT4 (a)T3 (a)T2 (a)T1 (a) 0.58350.68550.58354.2700.3400.1950.3400.195 Rework Table 3 - Flap Tracks 65-67156-2/-12/-14 MAXIMUM ALLOWABLE HOLE DIAM- ETERS MINIMUM ALLOWABLE DIMENSIONS d3d2d1WT4 (a)T3 (a)T2 (a)T1 (a) 0.58350.68550.58354.2700.3480.2080.3480.208 Rework Table 4 - Flap Tracks 65-46427-35/-39 MAXIMUM ALLOWABLE HOLE DIAM- ETERS MINIMUM ALLOWABLE DIMENSIONS d3d2d1WT4 (a)T3 (a)T2 (a)T1 (a) Do Not Rework - Remove from service if damaged Rework Table 5 - Flap Tracks 65C34809-2 & 65C35387-2 & 65C35616-3 MAXIMUM ALLOWABLE HOLE DIAM- ETERS MINIMUM ALLOWABLE DIMENSIONS d3d2d1WT4 (a)T3 (a)T2 (a)T1 (a) 0.58350.68550.58354.2700.3400.1950.3400.195 The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT (SHEET 3 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 54 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 55 NOTESQTYPART NUMBERNAMETASKSTEP (a)--CorrosionRemove1 (b)--Repair AreaMeasure2 (c)169-37234-( )BushingRemove3 (d)1-HoleInspect4 --DiameterIncrease --DiameterMeasure Shot peen the holes as given in BSOPM 20-10-03, Intensity.012A, Coverage 2.0. 1-HoleShot peen Apply cadmium-titanium alloy plating to the holes as given in BSOPM 20-42-02. --PlatingApply (e)2-HoleInspect5 --DiameterIncrease --DiameterMeasure Shot peen the holes as given in BSOPM 20-10-03, Intensity.012A, Coverage 2.0. 2-HoleShot peen Apply cadmium-titanium alloy plating to the holes as given in BSOPM 20-42-02. --PlatingApply Shot peen all surfaces of the repair area as given in BSOPM 20-10-03, Intensi- ty.012A, Coverage 2.0. --Repair AreaShot peen6 Apply cadmium-titanium alloy plating to all surfaces of the repair area as given in BSOPM 20-42-02. --PlatingApply7 (f)1-Repair BushingMake8 --PlatingApply Install bushing wet with sealant.-BMS 5-95SealantApply9 (g)1-Repair BushingInstall If corrosion was found during the inspection, refer to the track repair procedures given in the 737 OHM 57-53-15 and BSOPM 20-10-01, and remove the damaged material from the repair area of the track. Maintain flatness of the repaired surface. (a) Measure the width (W) of the track in the repair area. Measure the thickness (T) of the track in the repair area at the four locations shown. Do not include the thickness of the tapered shim. (b) If the width and thickness are in the limits shown in the tables: Continue with the inspection of the bushing. - If the width and thickness are not in the limits shown in the tables: Write to Boeing for repair instructions.- FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT (SHEET 4 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 55 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 56 Refer to BSOPM 20-50-03 and remove the bushing if it was rejected during the inspection.(c) Note: It can be necessary to remove the tapered shim before you remove the bushing. To remove the tapered shim use a heat gun to make the sealant soft, and then use steel lockwire to cut the sealant between the lower surface of the shim and the track. Find and record the thickness of the tapered shim before removal. To find the shim thickness do one of these procedures: — Measure the shim thickness before removal. — Refer to the thickness that is recorded on the decal bonded to the wing rear spar adjacent to the flap track. — Use the procedure given in 737-100/200 AMM 27-51-151 for Group 1 and Group 2 Airplanes and 737-300/400/500 AMM 27-51-49 for Group 3 Airplanes. Note: The anti-fret strip must be installed if you use the AMM procedure to find the shim thickness. Do a detailed visual inspection of the hole. Look for signs of corrosion.(d) If corrosion is found: Increase the hole diameter, as given in BSOPM 20-10-01, to remove corrosion. Make and install a repair bushing. Hole diameter, before bushing installation, must remain in the limits shown in the tables. - Do a detailed visual inspection of the d1 and d3 holes. Look for signs of corrosion.(e) — If corrosion is found: Increase the hole diameters as given in BSOPM 20-10-01 to remove the cor- rosion. Hole diameters must remain in the limits shown in the rework tables. Make the bushing from 15-5PH or 17-4PH 180-200 ksi Steel Bar, AMS 5643, as shown in the 737 OHM 57-53-15. Use the dimensions shown in this service bulletin illustration. The outer diameter (OD) must be 0.0015 - 0.0017 inches larger than the diameter of the hole. Apply cadmium plating to all surfaces of the bushing as given in BSOPM 20-42-05, Finish Code F-15.02. (f) Refer to BSOPM 20-50-03 and install the bushing with the shrink fit procedure. Make sure the bushing does not protrude above the upper surface of the track, within 0.000/ -0.003 inches. (g) FIGURE 6: TRACK REPAIRS AND BUSHING REPLACEMENT (SHEET 5 OF 5) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 56 of 77 BOEING SERVICE BULLETIN 737-57A1271 ### Page 57 (OCR) BOEING SERVICE BULLETIN 737-57A1271 SEE ® OUTBOARD SEE A ATTACH BOLT OO8 ALIGNMENT PIN FORWARD ATTACH WASHER BOLT - 5) BUSHING REAR AFT TRACK SPAR SUPPORT WEB FITTING ANTI-FRET STRIP REAR SPAR TAPERED SHIM CHORD LOWER 2 FLAP TRACK WING SKIN STEEL FLAP TRACK BUSHING FWD WASHER (3) • INBD NUT 346O WBL 254 N85652 FIGURE 7: ALIGNMENT - TRACK INSTALLATION (SHEET 1 OF 6) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 57 of 77 ### Page 58 (OCR) BOEING SERVICE BULLETIN 737-57A1271 INBOARD OUTBOARD ATTACH BOLT AFT TRACK ATTACH BOLT 11)14 SUPPORT FITTING FORWARD ATTACH BOLT 11) WASHER REAR BUSHINGS SPAR WEB ANTI-FRET STRIP REAR SPAR TAPERED SHIM CHORD LOWER (11) BARREL NUT WING AND RETAINER SKIN WASHER FLAP TRACK NUT 1. STEEL FLAP TRACK BUSHING FWD DINBD WBL 254 FIGURE 7: ALIGNMENT - TRACK INSTALLATION (SHEET 2 OF 6) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 58 of 77 ### Page 59 (OCR) BOEING SERVICE BULLETIN 737-57A1271 AFT TRACK SEALANT INBOARD SUPPORT 16) ATTACH BOLT FITTING OUTBOARD ATTACH BOLT LOWER WING SKIN LOCKWIRE 15) ANTI-FRET ASTRIP TAPERED NUT — SHIM —INBD A-A INBOARD ATTACH BOLT OUTBOARD ATTACH BOLT SEALANT FWD AFT TRACK LOCKWIRE SUPPORT FITTING →INBD B-B The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane. FIGURE 7: ALIGNMENT - TRACK INSTALLATION (SHEET 3 OF 6) Original Issue: September 11, 2003 Revision 3 February 13, 2012 BOEING PROPRIETARY - 737-57A1271 Copyright © Unpublished Work - See page 1 for details. 59 of 77 ### Page 60 NOTESQTYPART NUMBERNAMETASKSTEP (a)1-Alignment PinMake1 1-Alignment PinInstall (b)1-Flap TrackLift/Align/Hold2 Apply to the shank and threads of the bolt. -MIL-C-11796, Class 3CompoundApply3 (c)1BACB30LE7HU( ) or BACB30LE7HK( ) BoltInstall (c) Under bolt head.1BACW10AK-C7 or BACW10BN7SC Washer (c) Under nut.1 or 2NAS1149F0716P or AN960-716L Washer (c)1BACN10HR7C or BACN10HR7CD or BACN10B7L Nut Temporarily tighten the nut to 40-60 pound-inch. --TorqueApply4 Temporarily tighten the nut to 270-300 pound- inch. --TorqueApply5 Temporarily tighten the nut to 360-420 pound- inch. --TorqueApply6 (d)--Alignment PinInspect7 1-Alignment PinRemove8 Decrease the torque to 40-60 pound-inch. 1-NutLoosen9 Decrease the torque to 40-60 pound-inch. 1-NutLoosen10 (c)1NAS577-8A or NAS577B8A Barrel NutInstall11 1NAS578-8ARetainer -MIL-C-11796, Class 3CompoundApply (c)1BACB30LE8H( ) or BACB30LE8HU( ) or BACB30LE8HK( ) BoltInstall (e)1BACW10DN8Washer - Torque-In- dicating FIGURE 7: ALIGNMENT - TRACK INSTALLATION (SHEET 4 OF 6) BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: September 11, 2003 737-57A1271Revision 3 February 13, 2012 60 of 77 BOEING SERVICE BULLETIN 737-57A1271 The text continues at https://openairdocs.org/service-documents/boeing/737-57a1271/file/fc3ab069e51d.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.