Number: 737-53-1061 Date: May 28, 1982 Revision 4: July 16, 1992 ATA System: 5311

SUBJECT: FUSELAGE
- OVERWING FRAME INSPECTION, MODIFICATION AND REPAIR
- BODY STATION559 THROUGH 639
This revision includesall pages ofthe service bulletin. SUMMARY This revision is sent to identify a new stub beam lower chord for Body Station 597, new stub beam repairs for Body Stations 578 and 597, and new frame outer chord repairs for Body Stations 616 and639. Inspections have been clarified to include all of portions of the frames below Stringer S-16 and all of the stub beams at Body Stations 559, 578, 597, 616 and639. Inspection interval has been reduced to 4,500flight cycles. Post modification inspections of the circumferential frames at Body Stations 616 and 639 have been added. Illustrations have been clarified. Inspections have been added for airplanes that were changed as given in other releases of this service bulletin at Body Station597 and have not installed radius fillers. An inspection for Group 4 airplanes that have modified a circumferential frame at Body Station 597 has been added. Typical crack locations have been added to illustrations. Service history has been updated. Shimming instructions have been added to eliminate gaps that may exist between stub beams and body frames. Kit history and kit procurement information has been clarified. Additional access information has been added. A flight safetyaddendum has been added. Flightcontrol cabledisconnection and rigging instructions have been added. Maintenance manual references have been added. The retrofit flow chart has been updated and expanded. Paragraph I.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivityparagraphforchanges. More work is necessary on airplanes that have installed stub beam lower chords with 1/4 inch diameter fasteners at Body Station597 as given by Revisions 1,2 or 3 of this service bulletin. Morework is necessary on airplanesthat havechanged shear ties as givenin Revision 1,2 or 3of thisservice bulletin. The information contained in Notice of Status Changes 737-53-1061 NSC3, NSC4 and NSC5 have been incorporated Inthis revision. Vertical lines are put on the left edge of each page, except in Paragraph I.A., Effectivity,to show the location of importantchanges. Pageswith a revision numberand date, but no vertical lines have no importantchanges. REVISION HISTORY Initial Release: May28, 1982 Revision 1: December 16, 1983 Revision 2: April 18, 1986 Revision 3: June 15,1989 Revision 4: July 16, 1992Number: Date: Revision 4: ATA System: 737-53-1061 May 28, 1982 July 16, 1992 5311

SUBJECT: FUSELAGE
- OVERWING FRAME INSPECTION, MODIFICATION AND REPAIR
- BODY STATION 559THROUGH 639
BACKGROUND Based on a structural review of the 737 airplane, incorporation of the modification per this service bulletin is recommendedon aging airplanes. Thirty-six operators have reported 197cracks in the overwing body frames and stub beams between Body Stations 559 through 639 on 115 airplanes. There were cracks in shearties, webs, inboard and outboard chords of the body station frames. There were cracks in the webs, attach angles, upper and lower chords of the stub beams. There were 100 reports of cracks at Body Station 639 with 12 reports of severed body frame webs, 12 reports of severed body frame inboard chords, and 4 reports of severed body frame outboard chords. There were 70 reports of cracks at Body Station 597 with a 12 inch crack reported in the stub beam web and a 5 inch crack reported in the stub beam lower chord. The airplanes had accumulated between 9,400 to 74,900 flight cycles and 8,000 to 65,600 flight hours. Two operators have reported 15 sheared fasteners in the overwing body frames and stub beams between Body Stations 559 through 639 on 6 airplanes. Periodic inspection of the bodyframe and overwing stub beam structure at Body Stations 559 through 639 perthis service bulletin will detect cracks at an early stage of propagation. The installation of the preventive modificationwill reducethe possibility of fatigue cracks. Undetected fatigue cracks could lead to damage in adjacent structure and may result inextensive repairs. ACTION (PRR 32974, 32974-R, 33419 and 33421-R) On airplanes subject to the 737 Aging Airplane Structural Modification Program, accomplish modification at the thresholds given in the compliance sectionof this service bulletin. Remove seats, carpets, side panels and floor panels to get access to overwing stub beams and body frames between Body Stations 559 through 639. Do a detailed visual inspection of circumferential frames from Stringer S-16 down to the top of the center wing fuel cell. Do a detailed visual inspection of the stub beam at BodyStations 559, 578, 597, 616 and 639. Do inspections at the thresholds given in the compliance section of this service bulletin. If no cracks or damaged fasteners are found , repeat inspection at the thresholds given in the compliance section of this service bulletin until the preventive modification is done. If cracks or damaged fasteners are found within the limits given in this service bulletin, then repair per this bulletin. For Airplane Groups 1 through 3, accomplish an eddy current inspection of the Body Station 639 frame inboard chord fastener hole at Stringer S-16. If no cracks are found, repeat eddy current inspectionat the thresholds given inthe compliance section of this service bulletin until the preventive modification is accomplished. If cracks are found within the limits given in this service bulletin, repair perthis bulletin. The preventive modification for Airplane Groups 1 through 3 is as follows: reinforce body frame inner chords and flanges, replace stub beam lower chords, replace stub beam upper chords, replace stub beam attach angles to the BBL 45.5 floor beam, and reinforce the stub beam web at Body Stations597, 616and 639. Disconnect,connect rig and functional test some flight control cable systems when replacing stub beam webs. Entry into the center wing fuel tank will be necessary when replacing stub beam lower chords at Body Stations 559, 578 and597. The preventive modification for Airplane Group4 is as follows: Reinforce body frame inner chords andflanges at Body Stations 559, 578 and 597. Replace stub beam lower chords at Body Stations 559, 578 and 597. Replace stub beam upper chords at Body Station 597. Replace stub beam attach angles to the BBL 45.5 floor beam. Disconnect, connect, rig and functional test some flight control cable systems when replacing stub beam webs. Entry intothe centerwing fuel tankwill be necessary when replacing stub beam lower chords at Body Stations 559, 578and 597. If cracks or damaged fasteners are found and cracked component can be replaced by the preventive modification, accomplish the modification on the affected frame. If cracks are within limits of this service bulletin, then repair those cracks as given in this service bulletin. Do post modification inspections at Body Stations 616 and639 frames. COMPLIANCE Refer to Paragraph I.D in Service Bulletin EFFECTIVITY Airplane Line Numbers 1
- 848 divided into 4 groups MANPOWER Referto Paragraph Fin Service Bulletin MATERIAL INFORMATION Referto ParagraphG inService Bulletin

Jul 16/92 REV. 4: Jul 16/92 Summary Page 2 of 2Number: Date: Revision 4: ATA System: 737-53-1061 May 28, 1982 July 16, 1992 5311

SUBJECT: FUSELAGE
- OVERWING FRAME INSPECTION, MODIFICATION AND REPAIR
- BODY STATION 559THROUGH 639

I. PLANNING INFORMATION A. Effectivity 1. Airplanes Refer to Service Bulletin Index Document D6-19567, Part 3 for Airplane Variable Number, Line Number, and Serial Numberdata. An equivalent change is on subsequent production airplanes. Refer to PRRs 32974, 32974-R, 33419and33421-Rfor data about this change.

LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER CUSTOMER GROUP VARIABLE NUMBER AER LINGUS (ARL) 1 PG254-PG255 PG573 2 PK029 PK614 4 PY281 PY321-PY323 PG575 PK641-PK642 AEROLINEASARGENTINAS (ARG) 1 PH705-PH708 PH741-PH743 2 PK102-PK103 4 PY007-PY008 AIR ALGERIE (ALG) 2 PL717-PL725 4 PY051-PY053 AIR FRANCE (AFA) 2 PL502-PL503 AIR GABON S.A. (GBN) 4 PY191 AIR GUINEE (GNE) 4 PY651 AIR LANKA, LTD. (LNK) 1 PH701 PL802

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 Page 1 of 53LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUPVARIABLE NUMBER AIR MADAGASCAR (MAD)

1 PG375 2 PL793 AIR NAURU (NAU) 2 PK356 PK581 4 PY286 AIR NEW ZEALAND, LTD. (ANZ) 2 PK047 PK211 AIR NIPPON CO., LTD. (ANK) 1 PG582 AIR TANZANIA (TNZ) 4 PY611-PY612 AIR ZAIRE (ZAI) 4 PY111 PY113 PK213-PK214

AIRCRAFT SUPPORT GROUP (ASG) 4 PY342 PY344 ALASKA AIRLINES (ASA) 4 PY112 PY134-PY135 PY270 PY461-PY462 ALL NIPPON AIRWAYS CO. LTD. (ANA) 1 PG578-PG581 PG583-PG586 2 PK711-PK716 ALOHA (ALO)

1 PG046 PG629 PG705 2 PK286-PK287 PK305-PK306 PK691-PK695 4 PY001 PY005 PY231 PY242 AMERICA WEST AIRLINES, INC. (AMW)

1 PC004 PG036 PL801 2 PK082 PK283 PK625-PK626 PL081 AMERICAN AIRLINES, INC. (AAL)

1 PG271-PG276 PG351 PG403 ANGOLAAIRLINES (ANG) 2 PK661 4 PY162 ANSETT WORLDWIDE AVIATION SERVICES (AWW)

1 PA001 PA003-PA004 ARAMCO SERVICES CO. (ARM) 2 PL151 4 PY241 PY243-PY244 ATLANTA ICELANDIC (AID) 4 PY002 PY381

Jul 16/92 REV. 4: Jul 16/92 PY451

PL551-PL559

737-53-10612LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUPVARIABLE NUMBER AVENSA (AVN) 2 PK042-PK043 AVIATECA (AVT)

1 PG201 AVIATION SALES CO., INC. (ASC)

1 PG331 PG401-PG402 PG436 AVIOGENEX AIR TRANSPORT (AVG) 2 PL501 PL506 BAHAMASAIR (BAH) 2 PK351 PK353 PL061 BRAATHENS S.A.F.E. (BRT)

1 PJ031 PJ072 2 PJ004-PJ009 PK882 BRITANNIA AIRWAYS, INC. (BRI)

1 PJ101 PJ103-PJ106 2 PJ108 PJ110-PJ111 PJ113-PJ118 BRITISH AIRWAYS (BAB) 2 PK731-PK749 PK771-PK777 PK779 CAMEROONAIRLINES (CAM) 4 PY046-PY047 CANADIAN AIRLINES INTERNATIONAL LTD. (CDI)

1 PG651-PG652 2 PK026-PK028 PK221 PK358 PK881 PK884 PL401-PL411 4 PY151-PY154 PY303-PY304 PY421 PG572

PK215 PG574 PJ102

PL716
PK819

PK671-PK675 PK677-PK678 PK822 PL761-PL762 PL764-PL770 PY441 CARNIVAL AIR (CVL) 1 PG302 PG305 PG312 PL712 CASINO EXPRESS (CIN) 1 PG279 CAYMAN AIRWAYS (CAY) 2 PK222 PK561 CONTINENTALAIRLINES, INC. (CAL) 1 PA006-PA014 PA016-PA020 PG056 PG064 PG199 PG225 PG229 PG432-PG433 PG441-PG442 PG501-PG505 PG621-PG628 PG630 PG704 PL001 COPA COMPANIA PANAMENA DE AVIATION S.A. (COP) 1 PC001 2 PJ107 PJ112 4 PY341 CRUZEIRO DO SUL (CRU) 2 PK141-PK146

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 3LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUP VARIABLE NUMBER DAN AIR (DAN) 2 PK820 PL421 DELTA AIR LINES, INC. (DAL) 2 PK611 PK613 DRAGONAIR (DRG) 2 PK357 PK871-PKE E G AND G (EGN) 1 PG037 PG208 2 PL763 EGYPTAIR (EGP) 2 PK252 PK254-PK2 EURALAIR (ERA) 1 PG026 PG028-PG( 4 PY004 PY006 PK615 PK623-PK624
873 PG210

!55 PG215

PK257-PK258
329 EUROPEAERO SERVICE (EUR) 2 PK203 PK359 PK612 FAR EASTERN AIR TRANSPORT (FAT)

1 PA002 PA005 PG055 2 PK562 FAUCETT (COMPANIA DE AVIATION S.A. (FCT) 1 PA231 PC002 PG034 FRENCH POSTAL OFFICE (FPO) 4 PY101 PY302 GB AIRWAYS (GBA) 2 PK282 PL171 GOVERNMENT OF BRAZIL (BRZ) 2 PK068-PK069 GOVERNMENT OF MEXICO (MXG)

1 PC005 PG223 GOVERNMENT OF SHARJAH (SHJ) 2 PL581 GULFAIR (GUL) 2 PK461-PK468 PK616 PK824 HAPAG LLOYD (HAP) 2 PL504-PL505 HEAVYLIFTAIRCRAFT ENGINEERING (HVL) 2 PJ109 INDIAN AIRLINES (IND) 1 PH709 PH711-PH713 2 PH021-PH022 PH024 PK231-PK233 4 PY631 PG226 PG228 PG230

PG213

3 PK235-PK240 PM001-PM002

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 4 PG431LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUP VARIABLE NUMBER INTERNATIONAL AIR LEASES (IAL) 1 PG043 PG047-PG048 PG251 PG253 IRAN ISLAMIC REPUBLIC AIRLINE (IRN) 1 PH731 2 PK391 4 PY021-PY022 IRAQI AIRWAYS (IRQ) 4 PY141-PY142 ITALJET S.R.L. (ITJ) 2 PK432 JET AVIATION (JTA) 2 PL441 KENYA AIRWAYS (KEN) 2 PK253 PK256 LADECO (LDE) 2 PK212 PK830 LAN-CHILE S.A. (LAN) 2 PK360 PK825 LINA CONGO (LNA) 4 PY411 LINHAS AEREAS DE MOCAMBIQUE (LAM) 1 PH703 4 PY031 LUFTHANSA GERMAN AIRLINES (DLH) 2 PK901-PK932 4 PY345-PY346 LUXAIR (LUX) 2 PK451-PK452 MALAYSIAN AIRLINES SYSTEM BERHAD (MAS) 2 PK051 PL736-PL738 PL740-PL745 4 PY201 MALEV HUNGARIAN AIRLINES (HGA) 2 PK284-PK285 MARKAIR, INC. (ALK) 1 PG216 PG218-PG219 MIDWAY AIRLINES, INC. (MID) 2 PK622 PK628-PK629 NASA (NAS) 1 PA099 NIGERIA AIRWAYS, LTD. (NIA) 2 PL781-PL782

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 5LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUPVARIABLE NUMBER NORDAM (NOP) 2 PK352 NWT AIR (NTA) 4 PY132-PY133 OLYMPIC AIRWAYS (OLY) 2 PK301-PK304 PK307-PK310 PM021-PM023 P. T. AIRFAST (PTF) 1 PG204 PG278 PAN AFRICAN EXPRESS (PFX) 1 PG211 PAN AMERICAN WORLD AIRWAYS, INC. (PAA) 1 PG020-PG021 PETROLAIR SYSTEMS S. A. (PTS) 2 PL471 PLUNA (PLU) 2 PL201-PL203 POLARIS LEASING CO. (PLS) 1 PG202 PG205 PG207 PG220-PG222 PG438 PG577 4 PX701 PRIVATE FLIGHT DIRECTORATE (ABU DHABI) (ABD) 2 PK495 REPUBLIC OF NIGER (NIR) 4 PY166 ROYAL AIR MAROC (RAM) 2 PK271-PK273 PK826 SABA AIRLINES S. A. (SBA) 1 PG209 PG212 SABENA BELGIAN WORLD AIRLINES (SAB) 2 PK041 PK044-PK046 PK048-PK050 PK052-PK053 PK431 PK433 4 PY272-PY275 SAUDIARABIAN AIRLINES CORP. (SVA) 2 PK311-PK317 PL726-PL735 4 PY036-PY037 SAUDI ROYAL FLEET (SRF) 2 PK318 SERVICIOSAEREOS RUTASORIENTE, (SARO)(SEV) 1 PA015 PA021-PA022 SIERRA PACIFICAIRLINES (SRP) 1 PC003 PG203 PG217 2 PK627

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 6LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUP VARIABLE NUMBER SOLOMON AIRLINES, LTD. (SOI) 2 PK823 SOUTH AFRICAN AIRWAYS (SAA) 1 PG353-PG356 2 PL101-PL110 SOUTHWEST AIRLINES CO. (SWA) 2 PK091-PK099 PK541-PK559 PK621 SOUTHWEST-SWAL (SWL) 2 PK521 PK523-PK524 SUDAN (SUD) 4 PY156-PY157 SULTANAIR (SLR) 1 PJ001 PJ032 PL803 2 PK563 T A PORTUGUESES (TAP) 2 PK971 PK973 PL451-PL452 3 PK974 TACA INTERNATIONALAIRLINES, INC. (TAC)

1 PG059 PG352 2 PK223 4 PY131 TAN SAHSA HONDURASAIRLINES (SAH)

1 PJ071 PL711 2 PK081 PL758 THAI AIRWAYS INTERNATIONAL, INC. (TII) 2 PK511 PK514 TIME AIR SWEDEN AB (TIS) 1 PJ002-PJ003 TRANS EUROPEAN AIRWAYS (TEA) 2 PK281 TRANSAVIAAIRLINES (TAV) 1 PG074 2 PK501-PK503 PK821 4 PY102-PY103 TRANSPORTAERIEN TRANSREGLONAL (TTR) 4 PY003 PY301 PY361-PY362 TUNIS AIR (TUN) 2 PK861-PK863 4 PY621

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 7LISTING BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER, (CONTINUED) CUSTOMER GROUPVARIABLE NUMBER UNITED AIR LINES, INC. (UAL) 1 PG001-PG004 PG006-PG019 PG022-PG025 PG027 PG038-PG040 PG044-PG045 PG051-PG054 PG057 PG075 2 PK201-PK202 PL002-PL022 UNITED STATES AIR FORCE (USF) 1 PJ201-PJ219 PG030 PG032-PG033 PG060-PG063 PG065-PG072

USAIR, INC. (USA)

1 PG041-PG042 PG313-PG314 2 PK288-PK289 PG073 PG474 PK591-PK599 PG206 PG576 PK601-PK609 PG301 PK883 PG303-PG304 PG306-PG311 PM101 VARIG AIRLINES (VAR) 2 PK111-PK116 PK118-PK120 PL453-PL454 VASP (VSP) 1 PG435 2 PH011-PH013 4 PX071 PG437 PK061-PK062 PY222 PG439-PG440 PG471-PG473 PK065-PK067 PK241 PK354-PK355 PL756 VENEZUELA
- GOVERNMENT OF (VNZ) 2 PK070 VISCOUNT AIR SERVICE INC. (VAS)

1 PG224 WHIRLPOOL FINANCIAL CORP (ZZW)

1 PG214 WIEN AIRLINES (WIE) 4 PY343 PY401 XIAMEN AIRLINES CO. LTD. (XIA) 2 PK874 YEMEN AIRWAYS (YEM) 2 PK341 ZAMBIA AIRWAYS (ZAM) 2 PK291

Jul 16/92 REV. 4: Jul 16/92 737-53-10618LISTING BY VARIABLE NUMBER
GROUP 1 PA001-PA022 PG201-PG230 PG375 PG621-PG630 PJ001-PJ003 PL711-PL712 PA099 PG251-PG255 PG401-PG403 PG651-PG652 PJ031-PJ032 PL801-PL803 PA231-PA232 PG271-PG279 PG431-PG442 PG701-PG705 PJ071-PJ072 PC001-PC005 PG301 -PG314 PG471 -PG475 PH701-PH715 PJ101-PJ106 PG001-PG075 PG331-PG332 PG501 -PG505 PH731-PH732 PJ201-PJ219 PG199 PG351-PG356 PG571-PG586 PH741-PH743 PL001
GROUP 2 PH001 PK041-PK053 PK141-PK146 PK271-PK273 PK391 PK511-PK514 PK601 -PK609 PK691-PK695 PK861 -PK863 PL061 PL401-PL411 PL501-PL506 PL761-PL770 PH011-PH013 PK061-PK070 PK201-PK204 PK281-PK289 PK431-PK433 PK521 -PK524 PK611-PK616 PK711-PK716 PK871 -PK874 PL081 PL421 PL551-PL559 PL781-PL782 PH021-PH024 PK081-PK082 PK211-PK215 PK291 PK451-PK452 PK541-PK559 PK621-PK629 PK731-PK749 PK881-PK884 PL101-PL110 PL441 PL581 PL793 PJ004-PJ009 PK091-PK099 PK221-PK223 PK301-PK318 PK461-PK469 PK561-PK563 PK641-PK642 PK771-PK779 PK901-PK932 PL151 PL451-PL454 PL716-PL745 PM001-PM002 PJ107-PJ118 PK101-PK103 PK231 -PK241 PK341 PK495 PK581 PK661 -PK662 PK819-PK826 PK971-PK973 PL171 PL471 PL756 PM021-PM023 PK026-PK029 PK111-PK120 PK251-PK258 PK351-PK360 PK501-PK503 PK591-PK599 PK671-PK678 PK830 PL002-PL022 PL201-PL203 PL491 PL758 PM101 GROUP 3 PK974 GROUP 4 PX071 PY046-PY048 PY151-PY154 PY221 -PY222 PY301-PY304 PY411 PY621 PX701 PY051-PY053 PY156-PY157 PY231 PY321-PY323 PY421 PY631 PY001-PY008 PY101-PY103 PY161-PY162 PY241-PY244 PY341-PY346 PY441 PY651 PY021-PY022 PY111-PY113 PY166 PY270-PY275 PY361-PY362 PY451 PY031 PY131-PY135 PY191 PY281 PY381 PY461-PY462 PY036-PY037 PY141-PY143 PY201 PY286 PY401 PY611-PY612

2. Spares None

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 9B. Reason As a result of the FAA sponsored Aging Fleet Conference, a 737 Structures Working Groupwith Airline and Boeing members and FAA observerswas formed to review structuresservice bulletin modifications and recommend selected bulletins for incorporation on aging airplanes. This service bulletin modification has been recommended for incorporationon aging 737 airplanes. Periodic inspection of the body frame and overwing stub beam structure at Body Stations 559 through 639 perthis service bulletin will detect cracks at an early stage of propagation. The installation of the preventive modification will reduce the possibility of fatigue cracks. Undetected fatigue cracks could leadto damage in adjacentstructure and may result in extensive repairs. Thirty-six operators have reported 197 cracks in the overwing body frames and stub beams between Body Stations 559through 639 on 115airplanes. Body frames hadcracks in shearties, webs, inboard and outboard chords. Stub beams had cracks inwebs, attach angles, upper and lower chords. There were 100 reports of cracks at Body Station 639with 12 reports of severed bodyframe webs, 12 reports of severed body frame inboard chords, and 4 reports of severed body frame outboard chords. There were 70 reports of cracks at Body Station 597with a 12inch crack reported inthe stubbeam web and a 5 inch crack reported in the stub beam lower chord. The airplanes had accumulated 9,400 to 74,900 flight cycles and8,000 to 65,600flight hours. Two operators have reported 15 sheared fasteners in the overwing body frames and stub beams between BodyStations 559through 639 on 6 airplanes. Revision 1of this bulletin provided superseding modification and repair kits with new improved lower chords. The detailed visual inspection was expanded to include the attachment fasteners at the Body Station 597 stub beam frame lower chord to BBL 70.85 rib upper chord interface. The modification provided larger attach fasteners at Body Station 597. As a result of operator experience, Revision 2 was issued to add a special eddy current inspection for cracks in the Body Station 639 inboard chord and to provide operators with revised repair drawings indicating trim requirementsfor repair angle installationand correct repair angle part numbers. Also, a repairwas added for cracks in the frame inboard chord and web at Body Station 597, 616 and 639 on both sides of Groups 1, 2 and 3 airplanes. Revision 3 was issued to provide the recommendations of the 737 Structures Working Group. As a result of operator experience Revision 3was issued to provide operators with revised modification and repairdrawings. New kit andsupplemental kit informationwas provided. Revision 4 is issued to identify a new stub beam lower chord for Body Station 597 and new stub beam repairs for Body Stations 578 and 597, and new frame outer chord repairs for Body Stations 616 and 639. Inspection interval has been reduced to 4,500 flight cycles. Inspections have been clarified to includeall ofportions of the frames below Stringer S-16 andall of the stub beams at Body Stations559, 578, 597, 616 and639. Post modification inspections at Body Stations 616 and639 have been added. Illustrations have been clarified. Typical cracks have been added to illustrations. Shimming instructions have been added to eliminate gaps that may exist between stub beams and body frames. Service history has been updated. Kit history and kit procurement information have been clarified. Additional access information has been added. A flight safety addendum has been added. Flight control cable disconnection and rigging instructions have been added for the preventive modification. Maintenance Manual References have been added. On Group 4 airplanes,the requirementto replace the upper chord at Body Station 578 during preventive modification has been removed. The intent of Notice of Status Change 737-53-1061NSC4 has been incorporated. The retrofit flow chart has been updated and expanded.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 10A structural reassessment of the 737 airplane has been conducted underthe requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56 in accordance with Federal Aviation Regulation (FAR) 25.571, as amended in 1978, to ensure safe operation of 737 airplanes throughout their operational life. Based on a structural reassessment of the 737 airplane, it has been determined that the structure affected by this service bulletin is structurally significant and should be inspected in accordancewith the flight safety inspectionprogram inthe addendumto this service bulletin. C. Description On airplanes subject to the 737 Aging Airplane Structural Modification Program, accomplish modification atthe thresholds given inthe compliance sectionof this servicebulletin. Remove seats, carpets, side panels and floor panels to get access to overwing stub beams and body frames between BodyStations559 through639. Do a detailed visual inspection of circumferential frames from Stringer S-16 down to the top of the center wing fuel cell. Do adetailed visual inspection of the stubbeam at Body Stations559, 578, 597, 616 and 639. Do inspectionsat the thresholds given inthe compliancesectionof this service bulletin. If nocracks or damagedfasteners arefound, repeat inspectionat the thresholds given inthe compliance section ofthis service bulletin until the preventive modification is done. If cracks or damaged fasteners are foundwithinthe limitsgiven inthisservice bulletin,then repair perthis bulletin. Accomplish post modification detailed visual inspections of the circumferential frames at Body Station 616 and639 atthe times given inthe compliancesection. On airplanes in Groups 1through 3, accomplish an eddy current inspection of the Body Station 639 frame inboard chord fastener hole at Stringer S-16. If no cracks are found, repeat eddy current inspection at the thresholds given inthe compliance section of this service bulletin until the preventive modification is accomplished. If cracks are found, repair per this bulletin. The preventive modificationfor Airplane Groups 1through 3 is as follows: reinforce body frame inner chords and flanges, replace stub beam lower chords, replace stub beam upper chords, replace stub beam attach anglesto the BBL45.5floor beam,and reinforcethe stubbeam web at BodyStations597, 616 and 639. Disconnect, connect rig and functional test some flight control cable systems when replacing stub beam webs. Entry into the center wing fuel tank will be necessarywhen replacingstub beam lowerchords at BodyStations 559, 578and 597. The preventive modificationfor Airplane Group 4 is as follows: Reinforce body frame inner chords and flanges at Body Stations 559, 578 and 597. Replace stub beam lower chords at Body Stations 559, 578 and597. Replacestub beam upperchords at BodyStation 597. Replacestub beam attach angles to the BBL 45.5 floor beam. Disconnect, connect, rig and functional test some flight control cable systems when replacing stub beam webs. Entry into the center wing fuel tank will be necessarywhen replacingstub beam lower chordsat BodyStations559, 578and597. On airplanes that have had the circumferential frames at Body Station 597 modified, visually inspect frame at Body Station 597 at the intervals given in the compliance section until radius fillers are installed. If cracks or damaged fasteners are found and cracked component can be replaced by the preventive modification, accomplish the modification on the affected frame. If cracks are within limits of this service bulletin, then repairthose cracks as given inthisservice bulletin. On Group 4 airplanes that have modified a circumferential frame at Body Station 578 with kit 65C22320-186, make surethe upper chord was not replaced.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 11Airplanes have been divided into4 groups. Airplane Groups 1through3 represent passengerairplanes that reinforce or replace the stub beams and body frames at Body Station 559, 578, 597, 616 and 639 at and below Stringer S-16. Airplane Groups 1 through 3 have different body frame repairs below Stringer S-16 at Body Station 597. Airplane Group 4 represents cargo airplanes that reinforce or replacethe stub beams and the body frames at Body Station 559, 578, 597, 616 and 639at and below StringerS-16. On airplanes that have installed stub beam lower chords with 1/4 inch diameter fasteners at Body Station 597 as given by Revisions 1, 2 or 3 of this service bulletin, do an inspection for short edge marginon the stub beam lowerchord and replaceas necessary. Thisservice bulletin is listed in Boeing Document D6-38505. NOTES: 1. Inspection and maintenance alternatives are shown in a diagram in Section III., ACCOMPLISHMENT INSTRUCTIONS. 2. If the damaged area is more than the specified limits,write to Boeing for repair instructions. To help Boeing send a reply, give the limits and location of the damage. When possible, send sketches and photographs. Ifthe damage includescorrosion, senddata onthe length,width, and largestdepth of clean up. SEND TO: BOEING COMMERCIAL AIRPLANE GROUP ATTENTION: MANAGER, AIRLINE SUPPORT 3. A retrofitflow diagram is provided inthe Accomplishment Instructions. 4. The last page of this service bulletin is an evaluationform. Please use this form to tell us what youthink ofthe quality ofthis service bulletin.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 12D. Compliance Based on a structural review of the 737 airplane, it is recommended that the modification per the Accomplishment Instructions of this service bulletin be accomplished prior to, or upon accumulation of 75,000flightcycles. Within 3,000 flight cycles of release of Revision 4 of this bulletin on airplanesthat have accumulated 15,000 or more flight cycles, accomplish a detailed visual inspection of circumferential frame from Stringer S-16 down to the top of the center wing fuel cell and of the stub beams at Body Stations 559, 578, 597, 616 and 639. If no cracks or damaged fasteners are found, repeat inspection at intervals not morethan 4,500 flight cycles until the preventive modification is done per Part IIof the accomplishment instructions. Within 24,000 flight cycles after the repair or preventive modification is done, do a detailed visual inspection of the BodyStations 616 and 639 framewebs, inner chords and outerchords near Stringer S-16. If nocracks are found,then repeat inspections at regular maintenance intervals of notmorethan 4,500 flightcycles. On Group 1
- 3 airplanes, at the nextscheduled maintenance periodwhen access to Body Station 639 Frame is available, accomplish the special inspection of the frame inboard chord fastener hole at Stringer S-16 at intervals of 15,000flight cycles. Repair any cracks found beforefurther flight. If no cracks are found, repeat eddy current inspections at 15,000 flight cycle intervals until the Part II preventive modification is accomplished. On airplanesthat havechanged circumferential frame at BodyStation 597 as given by original issue of this service bulletin, Revisions 1, 2 or 3 of this service bulletin, visually inspect the frames for cracks every 4,500 flight cycles. Dothese inspectionsuntil radiusfillers are installedas given by Revision4 of thisservice bulletin. Within3,000 flight cycles of releaseof Revision4 ofthis service bulletin, do aninspection forshort edge margin on the stub beam lowerchord on airplanesthat have installed stub beam lowerchords with 1/4 inch diameterfasteners at BodyStation 597as given by Revision 1,2or 3 ofthis service bulletin. This service bulletin describes a flight safety inspection program, in the addendum to this service bulletin, that is the minimum necessary to ensure the structural integrity of the stub beams and circumferentialframes between BodyStations 616and639. E. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The repairs and changes specified inthis service bulletin complywiththe applicable FederalAviation Regulations (FAR) and are FAA approved.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 13F. Manpower The data below shows an estimate of the man-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 man-hourdata if necessary. The estimate does notinclude losttime. Theseare some examples of lost time:

- Time to adjust to the workplace

- Time to schedule the work

- Time to examinethe work

- Timeto curethe materials

- Timeto makethe parts

- Time to findthe tools. Man-Hour Estimate PerAirplane (Repeat Inspection) Task Access Inspection Number of Persons 4 4 Restoration and 4 

### Operational Check TOTAL FOR
Man-Hour Estimate PerAirplane (Modification)Man-Hours 12 4 16

32 ElapsedTime (Hours) 3 1 4

8

Task Access Inspection Modification (Groups 1
- 3) Modification (Group 4) Restoration Cable Rigging and Operational Checks Numberof Persons 4 4 4

4

4 4 Man-Hours ElapsedTime (Hours) 32 6 288

116

32 16 8 1.5 72
29

8 8

TOTAL FORAIRPLANEGROUPS 1
- 3 TOTAL FOR AIRPLANEGROUP 4 374 97.5 202 54.5
NOTE: Man-hours to accomplish repairswill varydepending on type andextent of the repair.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 14G. Material- Priceand Availability Boeing can supply the kits shown in Paragraph II.A., Parts Necessary For Each Airplane, as shown below.
Kit Number

65C22320-1 65C22320-161 65C22320-162 65C22320-163 65C22320-164 65C22320-165 65C22320-166 65C22320-167 65C22320-168 65C22320-169 65C22320-171 65C22320-172 65C22320-173 65C22320-174 65C22320-175 65C22320-176 65C22320-179 65C22320-180 65C22320-181 65C22320-182 65C22320-183 65C22320-184 65C22320-185 Name Subkit Subkit Subkit Subkit Subkit Subkit Subkit Top Kit Top kit SupplementalSubkit SupplementalSubkit SupplementalSubkit Supplemental Subkit Supplemental Subkit Supplemental Subkit Supplemental Subkit Supplemental Subkit Supplemental Subkit Subkit Subkit Subkit Subkit Subkit Unit Pnce Inactiveforfuture procurement Inactivefor future procurement Inactivefor future procurement Inactivefor future procurement Inactivefor future procurement Inactivefor future procurement Inactiveforfuture procurement Inactiveforfuture procurement Inactiveforfuture procurement $3,717.00 $166.00 $1,311.00 $188.00 $5.00 $161.00 $161.00 $681.00 $546.00 $6,287.00 $6,398.00 Inactiveforfuture procurement Inactivefor future procurement $2,841.00

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 15Kit Number 65C22320-186 65C22320-187 65C22320-188 65C22320-2 65C22320-201 65C22320-202 65C22320-203 65C22320-204 65C22320-207 65C22320-208 65C22320-3 65C22320-4 65C22320-5 65C22320-6 65C22320-7 65C22320-75 65C22320-76 65C22320-8 65C25211-1 65C25211-101 65C25211-102 65C25211-105 65C25211-106 65C25211-11 65C25211-111 Name Subkit Top Kit Top Kit Subkit Top Kit Top Kit Subkit Subkit Supplemental Subkit Subkit Subkit Subkit Subkit Subkit Subkit Top Kit Top Kit Subkit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Unit Price Inactiveforfuture procurement Inactiveforfuture procurement Inactiveforfuture procurement Inactivefor future procurement $20,570.00 $6,558.00 $4,691.00 $3,166.00 $932.00 $1,627.00 Inactiveforfuture procurement Inactivefor future procurement Inactiveforfuture procurement Inactiveforfuture procurement $1,739.00 Inactivefor future procurement Inactivefor future procurement $2,196.00 $573.00 $520.00 $520.00 $199.00 $194.00 Inactiveforfuture procurement $709.00

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 16Kit Number 65C25211-112 65C25211-115 65C25211-116 65C25211-119 65C25211-12 65C25211-120 65C25211-121 65C25211-122 65C25211-123 65C25211-124 65C25211-125 65C25211-126 65C25211-129 65C25211-130 65C25211-133 65C25211-134 65C25211-137 65C25211-138 65C25211-141 65C25211-142 65C25211-143 65C25211-144 65C25211-145 65C25211-146 65C25211-147 Name Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Supplemental Repair Kit Supplemental Repair Kit Repair Kit Repair Kit Supplemental Repair Kit Supplemental Repair Kit Repair Kit Repair Kit Supplemental Repair Kit Supplemental Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Unit Price $709.00 $237.00 $237.00 $873.00 Inactiveforfuture procurement $873.00 $686.00 $686.00 $1,032.00 $665.00 $520.00 $520.00 $172.00 $172.00 $665.00 $665.00 $266.00 $266.00 $243.00 $192.00 $372.00 $372.00 $249.00 $208.00 $411.00

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 17Kit Number 65C25211-148 65C25211-2 65C25211-21 65C25211-22 65C25211-31 65C25211-32 65C25211-41 65C25211-42 65C25211-51 65C25211-52 65C25211-61 65C25211-62 65C25211-65 65C25211-66 65C25211-71 65C25211-72 65C25211-75 65C25211-76 65C25211-81 65C25211-82 65C25211-85 65C25211-86 65C25211-91 65C25211-92 65C25211-95 Name Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Unit Pnce $411.00 $473.00 $324.00 $324.00 Inactiveforfuture procurement $295.00 Inactiveforfuture procurement $686.00 $265.00 $265.00 Inactivefor future procurement Inactivefor future procurement Inactivefor future procurement Inactivefor future procurement $137.00 $137.00 $211.00 $211.00 $537.00 $537.00 $194.00 $194.00 $493.00 $493.00 $207.00

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 18Kit Number 65C25211-96 65C25211-97 65C25211-98 65C31658-1 65C31658-2 65C31658-3 65C31658-4 65C31658-5 65C31658-6 65C31658-27 65C31658-28 Date: July 16, 1992 Name Repair Kit Repair Kit Repair Doubler Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit Repair Kit

The kits are subject to the terms andconditions of Boeing's standard purchase order acknowledgment. The pricesare applicable from May 1, 1992through September 17,1992. After thisdate new pricedata is applicable. Prices are in United States Dollars. Terms: Net 30 days. Send purchase orders and letters about the supply data to the Director of Spares and refer to this service bulletin number. H. Special Tools- Priceand Availability None

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 19 Unit Pnce $207.00 $442.00 $124.00 $1,737.00 $1,791.00 $1,614.00 $1,635.00 $1,399.00 $1,399.00 $1,395.00 $1,386.00I. Weight and Balance Change inWeight Change in Moment Applicability (Pounds) (Pound-Inches) 65C22320-181 +15 +9,585 65C22320-182 +15 +9,240 65C22320-185 +7 +4,046 65C22320-203 +18 +10,746 65C22320-204 +12 +7,164 65C22320-208 +6 +3,468 65C22320-7 +5 +2,795 65C22320-8 +5 +2,795 Weight and Balance change for repairwill varydepending on extent of repairs. J. References 1. Existing Data:
a. Engineering Change Memo PRR32974-R, 32974,33421-R and33419 b. 737 Maintenance Manual Subjects 27-09-111, 27-51-0, 27-62-0, 28-10-00, 28-11-0, 28-11-31, 28-21-00, 28-23-0, 32-31-41 and53-10-3
c. 737 Structural Repair Manual Subjects 51-30-2 and51-50-1 d. 737 Structural Item InterimAdvisories 737-56 and 737-119
e. Boeing Standard Overhaul Practices ManualSubject 20-60-04 f. Boeing Document D6-38505 "Aging Airplane Service Bulletin Structural Modification Program
- Model 737-100/-200/-200C"

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 202. Datasupplied withthis service bulletin:
a. Drawings: Drawing Number 65C22320 Sheet DCN ADCN PL L 19 Title Frame InstallationOverwing, Body Station 559to 639,Top Kit 1 B 9 2 B W1 3 B 2 4 A 2 8 A 2 9 10 A 1 11 2 PL E 9 Repair Installation
- Overwing Stub Frames 1 B 4 2 A 2 3 4 PL A 3 Frame Installation
- Web and Chord Repair (Top Kit) 1 A 2 2 A 3 4 Boeing ProcessSpecifications referredto on drawings are not givenin this service bulletin since these procedures arefrequently usedasstandardshop practices.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 21 65C252111

65C316583. Installation Drawings: Drawing 65-46536 65-46537 65-46538 65-46539
65-46540 Title Frame Installation BodyStation 559 Frame Installation BodyStation 578 Frame Installation BodyStation 597 Frame Installation
- Emergency Escape Hatch BodyStation 616 Frame Installation
- Emergency Escape Hatch, BodyStation 639
These drawings were used to prepare this service bulletin. They are not necessary to make the changes specified. They are not supplied with this service bulletin. They may not be applicable to all airplane configurations oroperators. K. Publications Changed Publication Chapter-Section 737 Structural Repair Manual 737 Illustrated PartsCatalog 53-10 53-10
L. Electrical Load Data None

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 22II. MATERIAL INFORMATION A. Parts Necessary For EachAirplane 1. To getthe kits shownbelow, referto Paragraph I.G., Material
- PriceandAvailability. NOTE:The top kits are divided into subkits. Top kits and operator supplied materials specified in Paragraph II.A.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. Preventive Modification KitsforOverwing Framesfrom BodyStation559 to 639 -2011-2021-207 Quantity PartNumber Groups Name 3ody

.65C22320-201 35C22320-181 35C22320-182 65C22320-185 .65C22320-203 .65C22320-7 .65C22320-202 1

. 65C22320-204 1

. 65C22320-208
1 .65C22320-8

- 35C22320-207 Affected
1 through 3 1 through 3 1 through 3 1 through 3 1 through 3 1 through 3
4 4
4
4 1 through 4 Top Kit Sub Kit
- Stub Beam Replacement Sub Kit
- Stub Beam Replacement Sub Kit
- Stub Beam Upperand Lower Chord Replacement Sub Kit
- Stub Beam and Frame Change Sub Kit
- Stub Beam Lower Chord Replacement Top Kit Sub Kit
- Stub Beam and Frame Change Sub Kit
- Stub Beam Lower Chord Replacement Sub Kit
- Stub Beam Lower Chord Replacement Supplemental Kit- Stub Beam Lower Chord Replacement Stations Affected 559- 639 639 616 578 597 559 559 - 597 597 578 559 597

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 23 1
1
1
1
1PREVENTIVE MODIFICATION KIT HISTORY

Inactive Kit Number 65C22320-75 65C22320-167 65C22320-187 None 

### 65C22320-5 65C22320-165 65C22320-3 65C22320-163 65C22320-183 65C22320-2 65C22320-162 65C22320-1 65C22320-161 

### 65C22320-76 65C22320-168 65C22320-188 None 65C22320-6 65C22320-166 65C22320-186 65C22320-4 65C22320-164 65C22320-184 Supplemental Kit Number 65C22320-169 65C22320-172 65C22320-207 None None 65C22320-175 None 65C22320-173 65C22320-207 None 65C22320-180 None 65C22320-179 65C22320-170 65C22320-171 65C22320-207 None None 65C22320-176 None None 65C22320-174 65C22320-207 Replacing Kit Number 65C22320-167 (Top Kit) 65C22320-187 (Top Kit) 65C22320-201 * (Top Kit) 65C22320-7*(a) 65C22320-165 65C22320-185* 65C22320-163 65C22320-183 65C22320-203* 65C22320-162 65C22320-182* 65C22320-161 65C22320-181* 65C22320-168 (Top Kit) 65C22320-188 (Top Kit) 65C22320-202* (Top Kit) 65C22320-8*(a) 65C22320-166 65C22320-186 65C22320-208*(b) 65C22320-164 65C22320-184 65C22320-204*

(a) -7 and-8 Kits are original kits that do not replaceany kits. (b) -208 Kitdoes not containthe upper chords inthe -186 kit becausethe existing T section isa better installation.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 24 Body Station 559-639 559-639 559-639 559 578 578 597 597 597 616 616 639 639 559-597 559-597 559-597 559 578 578 578 597 597 597 Airplane Groups Affected 

## 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 1-3 4 4 4 4 4 4 4 4 4 4 *Active KitOVERWING STUB FRAME REPAIRKITS FROM BODY STATION 559TO 639 Kit Number

65C25211-101 65C25211-102 65C25211-105 65C25211-106 65C25211-111 65C25211-112 65C25211-115 65C25211-116 65C25211-141
65C25211-142
65C25211-143 65C25211-144 65C25211-81 65C25211-82 65C25211-85 65C25211-86 65C25211-91 65C25211-92 65C25211-95 65C25211-96 65C25211-125 65C25211-126 65C25211-129 Side Descntpion of Change

L Repair Kit
- Lower Chord R Repair Kit
- Lower Chord L Repair Kit
- Frame Attach Angle R Repair Kit
- Frame Attach Angle L Repair Kit
- Lower Chord R Repair Kit
- Lower Chord L Repair Kit
- Frame Attach Angle R Repair Kit
- Frame Attach Angle L Repair Kit- Stub Beam Web Cracks near Inner Chord R Repair Kit
- Stub Beam Web Cracks near Inner Chord L Repair Kit
- Stub BeamInboardWeb Crack R Repair Kit
- Stub Beam Inboard Web Crack L Repair Kit
- Lower Chord R Repair Kit
- Lower Chord L Repair Kit
- Frame Attach Angle R Repair Kit
- Frame Attach Angle L Repair Kit
- Lower Chord R Repair Kit
- Lower Chord L Repair Kit
- Frame Attach Angle R Repair Kit
- Frame Attach Angle L Repair Kit
- ShearTie R Repair Kit
- ShearTie L Supplemental Repair Kit
- ShearTie

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 25 Airplane Groups Affected 1through 3 1 through 3
1 through 3 1 through 3 4 4 4 4 1through 3

1through 3 Body 

### Station
559 559 559 559 559 559 559 559 578
578
578 578 578 578 578 578 578 578 578 578 597 597 597 1 1 1 1 1 1 4 4 4 4
1 1
1 through 3

through 3 through 3 through 3 through 3 through 3

through 3 through 3 through 3OVERWING STUB FRAME REPAIR KITS FROM BODY STATION 559 TO 639 65C25211-130 65C25211-133 65C25211-134 65C25211-137 65C25211-138 65C25211-145
65C25211-146
65C25211-147 65C25211-148 65C25211-71 65C25211-72 65C25211-75 65C25211-76 65C25211-121 65C25211-122 65C25211-124
65C25211-32 65C25211-51 65C25211-52 65C25211-97 65C25211-1 65C25211-119 65C25211-120 R Supplemental Repair Kit
- ShearTie L Repair Kit
- Shear Tie R Repair Kit
- Shear Tie L Supplemental Repair Kit
- ShearTie R Supplemental Repair Kit
- ShearTie L Repair Kit
- Stub BeamWeb Cracks near Inner Chord R Repair Kit
- Stub BeamWeb Cracks near Inner Chord L Repair Kit
- Stub Beam InboardWeb Crack R Repair Kit
- Stub Beam InboardWeb Crack L Repair Kit
- FrameAttachAngle R Repair Kit
- Frame Attach Angle L Repair Kit
- Frame Attach Angle R Repair Kit
- Frame Attach Angle L Repair Kit
- Stub BeamOutboard Web R Repair Kit
- Stub BeamOutboard Web L + R Supplemental Repair Kit
- Outboard Stub Beam Web R Repair Kit
- Stub Beam InboardWeb L Repair Kit
- FrameWeb nearStringer S-16 R Repair Kit
- FrameWeb nearStringer S-16 L Repair Kit
- Stub Beam InboardWeb L Repair Kit
- Stub Beam InboardWeb L Repair Kit
- Stub BeamOutboard Web R Repair Kit
- Stub BeamOutboard Web

Jul 16/92 REV. 4: Jul 16/92 1through 3 4 4
4 4 1 through 3

1through 3

1through 3 1 through 3 1 through 3 1 through 3 4 4 1 through 4 1 through 4 1through 4

1 through 4 1 through 4 1 through 4 1 through 4 1 through 4 1 through 4 1 through 4 

### 597 597 597 597 597 597
597
597 597 597 597 597 597 616 616 616
616 616 616 616 639 639 639

737-53-1061 26OVERWING STUB FRAME REPAIR 639 65C25211-123 L+R
639 65C25211-2 R 639 65C25211-21 L
639 65C25211-22 R KITS FROM BODY STATION 559 TO 639 Supplemental Repair Kit
- Outboard Stub Beam Web Repair Kit- Inboard Stub Beam Web Repair Kit
- Upper Web below Stringer S-16 Repair Kit
- Upper Web below Stringer S-16

OVERWING STUB FRAME REPAIR KIT HISTORY Body Inactive Kit Number Station
597 65C25211-61 597 65C25211-62 597 65C25211-65 597 65C25211-66 616 65C25211-31 616 65C25211-41 616 65C25211-42 639 65C25211-11 639 65C25211-12 Supplemental Kit Number
65C25211-129 65C25211-130 65C25211-137 65C25211-138 65C25211-98 65C25211-124 65C25211-124 65C25211-123 65C25211-123 Replacing Kit Number
65C25211-125 65C25211-126 65C25211-133 65C25211-134 65C25211-97 65C25211-121 65C25211-122 65C25211-119 65C25211-120

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 27 1through 4

1 through 4 1through 4

1 through 4

Airplane Group Affected 1through 3 1through 3 4 4 1through 4 1through 4 1through 4 1through 4 1through 4OVERWING FRAME INSTALLATION REPAIR KITS FROM BODY STATION 559 TO 639
- WEB AND
Side Descritpionof Change Airplane Groups Affected 65C31658-27 65C31658-28 65C31658-39 65C31658-40 65C31658-5 65C31658-6 65C31658-3 65C31658-4 65C31658-53 65C31658-54 65C31658-75
65C31658-76
65C31658-1 65C31658-2 65C31658-51 65C31658-52 65C31658-55 65C31658-56 L Top Kit
- Web Repair R Top Kit-Web Repair L Top Kit
- Web Repair R Top Kit
- Web Repair L Top Kit
- Web Repair R Top Kit
- Web Repair L Top Kit
- Web and Inboard Chord Repair R Top Kit
- Web and Inboard Chord Repair L Top Kit
- OuterChord Repair R Top Kit
- OuterChord Repair L Top Kit
- Web, Inboard Chord and Outboard Chord Repair R Top Kit
- Web, Inboard Chord and Outboard Chord Repair L Top Kit
- Web and Inboard Chord Repair R Top Kit
- Web and Inboard Chord Repair L Top Kit
- Outer Chord Repair R Top Kit
- Outer Chord Repair L Top Kit
- Inner and Outer Chord and Web Repair R Top Kit
- Innerand OuterChord and Web Repair

Jul 16/92 REV. 4: Jul 16/92 2 2 3 3
1 1 1 through 3 1through 3 1through 3 1through 3 4

4

1 through 3 1 through 3 1 through 3 1through 3 4 4

737-53-1061 28 CHORD Body Station Kit Number



### 597 597 597 597 597 597 616 616 616 616 616
616
639 639 639 639 639 6392. Parts and Materials Suppliedbythe Operator: NOTE: Referto 737 Structural Repair ManualChapter51 foralternative fasteners. Part Number (Specification) BMS 5-81
BMS 5-95-1/2, -2 or -4 (b) BACS40R 7075-T6 Name Secondary Fuel Barrier Sealant Sealant Shim Aluminum Stock for Radius Fillers (a) 1 quart should be the maximum quantity of sealant necessary when secondary fuel barrier needsto be repaired. (b) See Boeing Standard PracticesOverhaul ManualSubjects 20-50-12 and20-60-04 (c) There are ten possible shim locations they may or may not need shims depending on whether or notgaps exist. B. Parts Necessaryto ChangeSpares None C. Special Toolsand Equipment No specialtools or equipmentare necessaryto dothe change inthis service bulletin. Maintenanceand overhaul tools in manuals shown in Paragraph I.J., References, may be necessary. Examine operator tool supply to make sure all necessarytools are available. D. Existing PartsAccountability None

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 29 Quantity 

### 1Quart (a)

1 Quart (c) 1/8 x 3/4 x 8 inBLANK PAGE

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 30III. ACCOMPLISHMENT INSTRUCTIONS NOTES: 1. The paragraphs identified with letters give the general work instructions and the necessary tests. The instructions identifiedwith numberson the figuresgive the recommended sequence of steps. 2. The work instructionsare divided into five parts asfollows: Part I
- Inspection Part II
- Preventive Modification Part III
- Repair Part IV
- Special Inspection Part V
- Retrofit Flow Diagram 3. As recommended by the 737 Aging Fleet Structures Working Group, accomplish the Preventive Modification per Part II, except Paragraphs G and H, of the Accomplishment Instructions of this service bulletin prior to or upon accumulation of 75,000flight cycles. Paragraphs G and H were not included in 737 Aging Fleet Document D6-38505 Revision F because they address problems found afterthe 737 StructuresWorking Group reviewedthisservice bulletin. 4. Unlessspecified differently, these dimensionsandtolerances are used:

- All linear dimensionsare in inches

- Tolerance on lineardimensionsotherthan rivet and bolt edge margin is plus or minus0.03 inch

- Tolerance on rivetand bolt edge margin is plus or minus0.05 inch

- The hole dimensionsforstandard solid rivets arefound in737 Structural Repair ManualChapter51

- The torque limitsto tighten nutsand bolts arefound in737 Structural Repair ManualChapter51. 5. Flow charts that represent these accomplishment instructions follow these accomplishment instructions. 6. Referto 737 Structural RepairManual Chapter51for alternativefasteners. 7. Obeyall warnings andcautions inthe specified manualsections.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 31Part I- Inspection A. Removeseats,carpet, floor panels andside wall panels as requiredto gain accessto the overwing stub beams and portions of thebody frames at BodyStations 559, 578, 597, 616and 639. B. Accomplish adetailed visual inspectionfor cracks anddamaged fasteners of overwing stub beams and body frames per Figure 1. C. On airplanes that have installed stub beam lower chords with 1/4 inch diameter fasteners at Body Station 597 as given by Revisions 1, 2 or 3 of this service bulletin, do an inspection of the stub beam lower chord for short edge margin as given in Figure 1. If edge margin is less than 1.5D, do an inspection forcracks as given in Figure 1or replace lower chord as given in Paragraph H of Part II of these Accomplishment Instructions at times given in the compliance section. Refer to 737 Structural Repair Manual Subject 51-30-2for more information on removal and installation of fasteners. D. On airplanes that havechanged either circumferential frame at Body Station 597 as given by Revision 1,2 or 3of this service bulletin,visually inspect the framesforcracks. Dothis inspection atthe intervals given in the compliance section until radius fillers are installed as given in Paragraph G of Part II of these accomplishment instructions. E. If no cracks or damaged fasteners are found, repeat inspections as given inthe compliance section of this service bulletinor accomplish Part II PreventiveModification. F. If cracks or damaged fasteners are found within limitsgiven in Figure2, accomplish repair per Part III- Repair. G. On airplanesthat have hadthe repair or preventive modification onthe frames at Body Station 616and 639, do a detailed visual inspection of the Body Stations 616 and 639 frame webs, inner chords and outerchords near Stringer S-16. If no cracks arefound, then repeat inspections. Dothese inspections at times given inthe compliance section ofthis service bulletin. H. On Group 4 airplanes that have modified a circumferential frame at Body Station 578 with kit 65C22320-186, make surethe upper chord was not replaced. I. If the upper chord was replaced on Group 4 airplanes at Body Station 578 with kit 65C22320-186, contact Boeing for instructions. J. Reinstall components removed inStep A. Return airplaneto normal.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 32Part II
- Preventive Modification NOTES:1. The followinginstructions supplement information contained on Drawing65C22320. Unless otherwise noted, all referencesareto that drawing. 2. Entry into the center fuel cell is not necessary if only the stub beams at Body Stations 616 or 639are being preventively modified. A. Defuel airplane (Ref. 737 Maintenance Manual Subject 28-23-00). B. Purgecenterwing fuelcells, if installed (Ref.737 Maintenance ManualSubject 28-10-00). C. Remove center wing access panels and fuel cells, if installed,to gain access to overwing stub beam attachments in number 1 and2 fuelcell cavities (Ref.737 Maintenance ManualSubject 28-11-31). D. Disconnect flight control cables to replace stub beam webs. Refer to 737 Maintenance Manual Subjects 27-09-111 and27-62-0 for more informationto disconnect speedbrake cables SBA and SBB that go into spoiler mixer quad on the left side of the airplane. Refer to 737 Maintenance Manual Subjects 27-09-111 and 32-31-41 for more informationto disconnect landing gear valve cables LGVA and LGVB on the left side of the airplane. Refer to 737 Maintenance Manual Subjects 27-09-111 and 27-51-0for more informationto disconnectwing flap cablesWFA andWFB. E. On Groups 1,2, and3 airplanes, modifyoverwing stub beams at Body Stations559, 578, 597, 616 and 639 per Drawing65C22320 using kits65C22320-7,-185, -203,-182 and-181. NOTES: 1. When replacing 4 attach fasteners common to the plus chord andthe stub beam lower chord at the Body Station 597, maintain a minimum edge margin of 1.5D. 2. It will be necessary to scrape sealant away from the outboard end of the stub beam lower chord to get clearance to remove the lower chord. The lower chord is replaced during preventive modification ofthe stub beams at BodyStations 559, 578, and597. 3. Repair any secondaryfuel barrier sealant removed ordamagedduring installationof any stub beams parts (Ref.737 MaintenanceManual28-11-0). 4. Shim any gaps morethan 0.01 inch that exist between the frame and the stub beam to reduce pull down stresses. Gaps may occur after installation of the stub beam to floor beam fasteners and before installation of the frame to stub beam fasteners. Take measurements inthe following four areas for all 5 overwing frames on each side of the airplane: upper inboard chord area, upper outboard chord area, lower inboard chord area, and lower outboard chord area. Shimsthat are more than 0.05 inch thick should pick up a second row of fasteners. Gaps between the frame web and the stub beam must havea shim installedthat fillsthe complete frameto stub beamjoint. Install single anddouble tapered shims (Ref BACS40Ror equivalent)with afaying surface seal (Ref. BMS 5-95). If any gaps are more than 0.2 inch contact Boeing for instructions. 5. If 1.5D edge margin can not be maintainedduring installation of -39 or -40 shear ties in kit 65C22320-203, then trim the shear tie flange to clear the existing rivets. Maintain 10:1 ratio when trimming flange. Install two rivets MS20470D6 in the partially trimmed flange. Maintain 1.5D edge margin. Install rivets in linewith other rivets increase beam outerchord. Maintain3D minimumfastener spacing alongcrease beam outerchord.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 33F. On Group 4 airplanes, modify overwing stub beams at Body Stations 559, 578, and 597 per drawing using kits65C22320-8, -208 and-204. NOTES: 1. When replacing attach fasteners for the lower chord of the stub beam at Body Station 597, maintain a minimum edge margin of 1.5D. 2. It will be necessary to scrape sealant away from the outboard end of the stub beam lowerchord to getclearanceto remove the lowerchord. 3. Repair any secondary fuel barrier sealant removedor damaged during installation of any stubbeams parts (Ref.737 Maintenance ManualSubject 28-11-0). 4. Shim any gaps morethan 0.01 inch that exist between the frame andthe stub beam to reduce pull down stresses. Gaps may occur after installation of the stub beam to floor beam fasteners and before installation of the frame to stub beam fasteners. Take measurements in the following four areas on each side of the airplane: upper inboard chord area, upper outboard chord area, lower inboard chord area, and lower outboard chord area. Shims that are more than 0.05 inch thick should pick up a second row of fasteners. Gaps between the frame web andthe stub beam must have a shim installed that fills the complete frame to stub beam joint. Install single and double tapered shims (Ref BACS40R or equivalent) with a faying surface seal (Ref. BMS 5-95). If any gaps are morethan 0.2 inch contact Boeingfor instructions. 5. During installation of kit 65C22320-204, if the -45 or -46 shear ties can not be installed because of interference with existing rivets in the plus chord flange, then trim the shear tie flange to clear the existing rivets. Maintain 10:1 ratio when trimming flange. Install two rivets MS20470D6 in the partially trimmed flange. Maintain 1.5D edge margin. Install rivets in linewith other rivets in crease beam outer chord. Maintain3D minimum fastener spacing along crease beamouter chord. G. On Group 1through 4 airplanes, install radius fillers as given in Figure 4 during modification of frame at BodyStation 597. H. On any Group 1through 4 airplanes with a short edge margin in the stub beam lower chord at Body Station 597, replacethose lower chords per drawing using kits65C22320-207. NOTES: 1. When replacing attach fasteners for the lower chord of the stub beam at Body Station 597, maintain a minimum edge margin of 1.5D. 2. It will be necessary to scrape sealant away from the outboard end of the stub beam lower chordto get clearanceto remove the lower chord. 3. Repair any secondary fuel barrier sealant removed or damagedduring installation of any stub beams parts (Ref.737 Maintenance Manual Subject 28-11-0). 4. Shim any gaps morethan 0.01 inch that exist between the frame and the stub beam to reduce pull down stresses. Gaps may occur after installation of the stub beam to floor beam fasteners and before installation of the frame to stub beam fasteners. Take measurements in the lower inboard and outboard chord areas on each side of the airplane. Shims that are more than 0.05 inch thick should pick up a second row of fasteners. Gaps betweenthe frameweb and the stub beam must have ashim installed that fillsthe complete frame to stub beamjoint. Install single anddouble tapered shims

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 34(Ref BACS40R or equivalent) with a faying surface seal (Ref. BMS 5-95). If any gaps are more than 0.2 inch contact Boeing for instructions. I. Clean center wing fuel tank, reinstall fuel cells removed for access and close fuel tank (Ref. 737 Maintenance ManualSubject 28-11-31). J. Refuelairplaneandcheck forfuel leaks (Ref. Maintenance ManualSubjects 28-21-0 and28-11-0). K. Connect and rig flight control cables that were disconnected for stub beam web replacement. Referto 737 Maintenance Manual Subjects 27-09-111and 27-62-0for more informationto connect speedbrake cables SBA and SBB that go into spoiler mixer quad on the left side of the airplane. Refer to 737 Maintenance Manual Subjects 27-09-111 and 32-31-41 for more informationto connect landing gear valve cables LGVA and LGVB on the left side of the airplane. Refer to 737 Maintenance Manual Subjects 27-09-111 and27-51-0for more informationto connectwing flap cablesWFA andWFB.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 35Part III- Repair NOTES: 1. If removal of fasteners that attach the lower chord of the stub beam frames to the top of the center fuel cell becomes necessary,then gainaccess for entry into center fuel cell as given in Part IIof these accomplishment instructions. 2. If removal of web is necessary,then disconnect flight control cables. Disconnectflight control cables to replacestub beam webs. Referto 737 Maintenance Manual Subjects 27-09-111and 27-62-0 for more information to disconnect speedbrake cables SBA and SBB that go into spoiler mixer quad on the left side of the airplane. Referto 737 Maintenance ManualSubjects 27-09-111 and 32-31-41 for more information to disconnect landing gear valve cables LGVA and LGVB on the left side of the airplane. Refer to 737 Maintenance Manual Subjects 27-09-111 and 27-51-0for more informationto disconnectwing flap cables WFA andWFB. 3. Repair any secondary fuel barrier sealant removed or damaged during installation of any stub beams parts (Ref.737 Maintenance Manual Subject 28-11-0). 4. If access must be gained for replacement ofthe lowerportion of frames at BodyStation 616 or 639, Stringer S-16 may be cut midway between body station frames while taking care not to damage the skin. Referto 737 Structural Repair Manual Subject 53-10-3 Figure 1 Detail IIfor more information on splicing the stringer. Use stringer splice material 69-78188-17to restore strnger to normal. A. If cracked component can be replaced by installation of the appropriate preventive modification kit, accomplish Part II Preventive Modificationforthe affectedframe. B. If cracked part is covered in and is within the repair limits of Figure 2, accomplish applicable repair per Repair Drawing65C25211 or 65C31658. C. If cracked components can not be replaced or repaired per Step A or Step B,then contact Boeing for repair instructions.

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 36Part IV
- Special Inspection A. If not already accomplished, remove seats, carpet, floor and side panels as required to gain access to BodyStation 639 Frameon both sides of the airplane. B. Eddy-current inspect inboard chord of frame at Body Station 639 per Figure 3 for cracks propagating from the inboard fastener hole at Stringer 16. C. Ifcracks are found, repair per Part III
- Repair. D. If no cracks arefound, repeat inspection at thethreshold given inthe compliance sectionof this service bulletin until BodyStation 639frame is preventivelymodified per Part II
- PreventiveModification. E. Reinstallfloor panels, sidepanels, carpets andseatsthat were removed foraccess and restoreairplane to normal.

Jul 16/92 737-53-1061 REV. 4: Jul 16/92 37AIRPLANES THAT HAVE NOT BEEN REPAIRED OR PREVENTIVELY MODIFIED AS GIVEN IN SERVICE BULLETIN 737-53-1061 REVISION

AIRPLANES WITH LESS THAN 15,000

FLIGHT CYCLES

UPON ACCUMULATION

OF 15,000 FLIGHT CYCLES AIRPLANES WITH 15,000 FLIGHT CYCLES OR MORE

WITHIN3,000 FLIGHT CYCLES

AT A REGULAR SCHEDULED MAINTENANCE PERIOD:

(A) VISULLY INSPECT FRAMES AT BS 559, 578, 597, 616 AND 639 PER PART I INSPECTION, GROUPS 1-4 AIRPLANES (B) EDDY-CURRENT INSPECT BS 639 FRAME AT S-16 PER PART IV SPECIAL INSPECTION, GROUPS 1-3 AIRPLANES ONLY REINSPECT EVERY 15,000 FLIGHT CYCLES

NO CRACKS OR DAMAGED FASTENERS

REINSPECT EVERY 4,500

FLIGHT CYCLES UNTIL PREVENTIVE MODIFICATION IS DONE

MODIFY EACH UNREPAIRED FRAME OR PART OF FRAME NOT REPAIRED PER PART II PREVENTIVE MODIFICATION CRACK OR DAMAGED FASTENER FOUND

REPLACE CRACKED PART PER PART II PREVENTIVE MODIFICATION OR REPAIR CRACKED PART PER PART III REPAIR

FOR EACH FRAME OR PART OF FRAME NOT REPLACED OR REPAIRED FOR EACH FRAME OR PART OF FRAME

REPLACED OR REPAIRED

AT BODY STATIONS 559, 578 AND 597 NO FURTHER ACTION PER THIS BULLETIN

AT BODY STATIONS 616 AND 639 CONTINUE TO DO POST MODIFICATION INSPECTIONSAT TIMES GIVEN IN COMPLIANCE SECTION

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 38 )AIRPLANE MODIFIED OR REPAIRED AS GIVEN BY THE ORIGINAL ISSUE, REVISION 1, REVISION 2 OR REVISION 3 OF SERVICE BULLETIN 737-53-1061

AIRPLANES THAT HAVE HAD STA 597 CIRCUMFERENTIAL FRAME MODIFIED AIRPLANES THAT HAVE HAD STA 616 OR 639 CIRCUMFERENTIAL FRAMES MODIFIED

VISUALLY INSPECT CIRCUMFERENTIAL FRAME AT STATION 597 EVERY 4,500 FLIGHT CYCLES UNTIL RADIUS FILLERS ARE INSTALLED INSPECT STUB BEAM LOWER CHORD AT STATION 597 FOR SHORT EDGE MARGIN WITHIN 3,000 FLIGHT CYCLES DO POST MODIFICATION VISUAL INSPECTIONS WITHIN 24,000 FLIGHT CYCLES AND THEN EVERY 4,500 FLIGHT CYCLES

EDGE MARGIN IS LESS THAN 1.5D, CONTINUE TO INSPECT EVERY 4 500 FLIGHT CYCLES OR REPLACE

STUB BEAM LOWER CHORD EDGE MARGIN IS MORE THAN 1.5D

NO MORE ACTION IS NECESSARY

AIRPLANE PARTS NOT MODIFIED OR REPAIRED SHOULD BE INSPECTED OR MODIFIED AS GIVEN IN THE PREVIOUS FLOW CHART FOR AIRPLANES THAT HAVE NOT BEEN REPAIRED OR MODIFIED

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 39IllustrationTable of Contents Title Page Figure 1. Inspection 39 Figure 2. Repair Limits 43 Figure 3. Special Inspection 46 Figure 4. Radius Filler Fabrication and Installation 49

Jul 16/92 REV. 4: Jul 16/92 737-53-1061 40FIGURE 1. INSPECTION Jul 16/92 REV. 4: Jul 16/92 737-53-1061 41FIGURE 1. INSPECTION Jul 16/92 REV. 4: Jul 16/92 737-53-1061 42FIGURE 1. INSPECTION
Jul 16/92 REV. 4: Jul 16/92 737-53-1061 43FIGURE 1. INSPECTION
Jul 16/92 REV.4: Jul 16/92 737-53-1061 44Figure 2. Repair Limits Jul 16/92 REV. 4: Jul 16/92 737-53-1061 45Figure 2. Repair Limits Jul 16/92 REV. 4: Jul 16/92 737-53-1061 46Figure 2. Repair Limits
Jul 16/92 REV. 4: Jul 16/92 737-53-1061 47Figure 2. Repair Limits Jul 16/92 REV. 4: Jul 16/92 737-53-1061 48Figure 3. Special Inspection
Jul 16/92 REV. 4: Jul 16/92 737-53-1061 49Figure 3. Special Inspection Jul 16/92 REV. 4: Jul 16/92 737-53-1061 50FIGURE 4. RADIUS FILLER FABRICATION AND INSTALLATION
Jul 16/92 REV. 4: Jul 16/92 737-53-1061 51FIGURE 4. RADIUS FILLER FABRICATION AND INSTALLATION Jul 16/92 REV. 4: Jul 16/92 737-53-1061 52FIGURE 4. RADIUS FILLER FABRICATION AND INSTALLATION
Jul 16/92 REV. 4: Jul 16/92 737-53-1061 53ADDENDUM FLIGHT SAFETY SECTION INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME

Table I is a summary of inspections specified in Accomplishment Instructions, Part I
- Flight Safety Inspection Program, that are recommended for the detection of cracks prior to their reaching critical lengths. Failure to detect cracks prior to their reaching critical length may result in failure of the escape hatch door frames at Body Station 616and639 resulting in progressivefailure of adjacentstructure. Any cracked structure should be repaired or your cognizant regulatory agency. Please report any discrepancies to Boeing described inthe addendum.

AirplaneCondition

Service Bulletin Modification or Repair not accomplished Inspection

Detailed Visual replaced prior to further flight unless specifically approved by

Customer Support Engineering using the reporting system

TABLE I InspectionThreshold (Flight Cycles) 15,000 FlightCycles Repeat Inspection Interval (FlightCycles) 4,500 FlightCycles NOTE: For airplanes with morethan 15,000 flight cyclesat receiptof thisservice bulletin, do the inspectionwithin 3,000flight cycles. Service Bulletin Modification or Repair accomplished Detailed Visual 24,000 FlightCycles after preventive modification or repair 4,500 FlightCycles

NOTE: For airplanes with morethan 24,000 flight cycles after modification or repair at receiptof this service bulletin, dothe inspectionwithin 3,000 flight cycles.

ADDENDUM Jul 16/92 REV. 4: Jul 16/92Boeing requests that operators use the following Structural Significant Item (SSI) Reporting System to report any discrepancies thatarefound inaccomplishing a Flight Safety Inspection.

1. Upon recognitionof discrepancy, the following information should be telegraphedto Boeing: Heading: ATTENTION
- SSI DISCREPANCY
- SERVICE BULLETIN RELATED

- Service Bulletin number

- Airplaneserial number onwhich discrepancywas found

- Identificationof structural itemfound damaged

- Flightcycles and hours ondamaged item

- Locationanddescription of damage includingdirection and size

- When discovered and inspection method used Sendtelegramthrough Boeing Field Service Representative ordirectlyto: 737Customer Support Engineering 2. An Operator's Follow-Up Report containing all available pertinent data, relative to the structural discrepancy, shall be sentto Boeing. Asummary ofthe informationthat should be reported is shown in the DISCREPANT STRUCTURE REPORT form attached. Operators may use this form or any suitable alternative which contains the same information. 3. All data and reports dealing with the Flight Safety Inspection Program shall be submitted either through a Boeing Field Service Representative ordirectlyto: The Boeing Commercial Airplane Group P.O. Box 3707 Seattle,Washington 98124 Attn: Director,707/727/737 Customer Support Engineering Org. M-7470 Mail Stop 9H-96 4. All reportswill be reviewed promptly. 5. The Boeing Company will summarize the results of all reported significant data for distribution semi-annuallyto operators andappropriate AirworthinessAuthorities.

Jul 16/92 ADDENDUM REV. 4: Jul 16/92DISCREPANT STRUCTURE REPORT 1 REPORT DATA AIRLINE/AGENCY ATA INDEX STATION 2 AIRCRAFT DATA MFG SERIAL NO MODEL SERIES FUGHTHOURS TAIL NO FLIGHT CYCLES 3 COMPONENT DATA (AS APPLICABLE ANDAVAILABLE) NAME P/N IPC/DWG REF SRMREF COMPLETE THEFOLLOWING IFKNOWN ANDDIFFERENT FROM SECTION 2 COMPONENT FLIGHT HOURS SINCE NEW COMPONENT FLIGHT HOURS SINCE NEW 4 REPAIR DATA PLANNED C S/N

SINCE OVERHAUL SINCE OVERHAUL COMPLETED 4A ACTION

4B REFERENCE ASSOCIATED WITH INSPECTION/REPAIR (SPECIFY NO, PAGE. FIGURE, ECT) SB AD IPC SRM MPD OTHER (EGSDR,MRR) SIIA STRUCTURAL SIGNIFICANT ITEM NO. SERIES 50 NO. 5 SERVICE BULLETINS INCORPORATED IN AREA OF DISCREPANCY SERVICE BULLETIN APPLICABLE SECTION DATE OF NO OFSERVICE BULLETIN INCORPORATION TOTAL FLIGHT HOURS AND CYCLES ATINCORPORATION HOURS FUGHTS HOURS FUGHTS HOURS FUGHTS 6 INSPECTION DATA (COMPLETE KNOWN INFO,CHECK APPROPRIATE ITEMSFOR DISCREPANT STRUCTURE) CURRENT INSPECTION INTERVALS (FLIGHTS) CORRESPONDING INSPECTION LEVELS 6A WHEN DISCOVERED SCHEDULED MAINTENANCE OVERHAUL UNSCHEDULED SPECIALDIRECTED (AD,SB. ) SYMPTOM (FUEL/PRESS LEAK ) RELATED FLEET EXPERIENCE ACCIDENT INVESTIGATION SSID SERIES 50 6B INSPECTION LEVEL WALK-AROUND GENERAL VISUAL EXTERNAL SURVEILLANCE INTERNAL SURVEILLANCE DETAILED SPECIAL 6C DETECTION METHOD VISUAL TAPTEST MAGVISUAL SOUND DYEPENETRANT SMELL ULTRASONIC FEEL LOW X-RAY FREQUENCY PRESSLOSS EDDY CURRENT HIGH FREQUENCY EDDY CURRENT BORESCOPE MAGNETIC PARTICLE

Jul 16/92 REV. 4: Jul 16/92 ADDENDUM REPORT NO MONTH DAY YEARDESCREPANT STRUCTURE REPORT 7 DISCREPANCY DESCRIPTION:

Attach sketch, photos andtextasrequired todescribe defect andspecific location When applicable givedetails ofassociated discrepances onthesameaircraft, related experience withthis discrepancy onanyaircraft, andprevious modification (s)tothe discrepant structure 7A TYPE OF DISCREPANCY: BENT BROKEN BUCKLED BURNED CLOGGED CONTAMINATED CORRODED CRACKED DEFORMED DELAMINATED 7B SIZE OF DISCREPANCY: DENTED DETACHED IMPROPERLY ADJUSTED LEAK INCHES, OR AREA X CRACK LENGTH INITIALLY DETECTED FINAL MEASUREMENT (IFDIFFERENT) 7C DISCREPANT PART: FRAME/BULKHEAD PRESSURE BULKHEAD FRAME AROUND OPENING WINDOW FORGING KEELBEAM FLOOR WING CENTER SECTION WING DRY-BAY AREA/COMPT SPAR RIB LANDING GEAR BEAM FLAP TRACK FAIRING LOOSE MISSING OUT-OF-TOLERANCE STUCK WORN NRINKLED

CENTIMETERS DEPTH DATE DATE

SKIN PLATE/PANEL CHORD STRINGER NO BEAM STRUT/BRACE LINK/ROD LONGERON FITTING BRACKET/CUP STOP FASTENER JOINT/SPUCE LUG WELD BOND OPEN HOLE FASTENER HOLE CUT-OUT ACCESS/UGHTENING HOLE NOTCH/GROOVE DISCONTINUITY BASIC MATERIAL BUSHING PIN
7D LOCATIONOF DISCREPANT PART: GENERAL LOCATION (EG.,BILGE, UNDER GALLEY) BODY STA NO WING STA NO VERTSTABSTA HORIZ STAB STA NACELLE/PYLON COMPARTMENT NOSE LANDING GEAR MAINLANDING GEAR WING LANDING GEAR BODY LANDING GEAR DOOR/ACCESS PANEL RUDDER ELEVATOR AILERON FLAP SLAT SPOILER TAB(ALSO CHECK ABOVE)

INSPECTED BY INTERIOR INBOARD LEFT FORWARD UPPER LEADING EDGE MIDDLE SPECIFIC LOCATION EXTERIOR OUTBOARD RIGHT AFT LOWER TRAILING EDGE SIDE

REPAIRED BY ORIGINATED BY

Jul 16/92 REV. 4: Jul 16/92 ADDENDUM DATE SIDE 2Number: Date: Revision 4: ATA System: Prepared By: 737-53-1061 May28,1982 July 16, 1992 5311 John Bourgeois SUBJECT: FUSELAGE
- OVERWING FRAME INSPECTION, MODIFICATION AND REPAIR
- BODY STATION559 THROUGH 639
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