Commercial

Airplane

Group

737

Service Bulletin

Number: 737-53A1166 Revision Transmittal Sheet

Date: June 30, 1994

Revision 1: May 25, 1995

ATA System: 5311

SUBJECT: FUSELAGE - FRAMES - BODY STATION 727 OUTBOARD CHORD AT STRINGER 18A,

INSPECTION AND PREVENTIVE MODIFICATION

This revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

Federal Aviation Administration (FAA) Notice of Proposed Rule Making, FAA Docket Number

94-NM-159-AD, is related to this service bulletin.

No more work is necessary on airplanes changed as shown in the initial release of this service bulletin.

SUMMARY

This revision is sent to add a stringer 18A outer chord repair. In addition, instructions have been added, to

trim "Time Limited Repair" parts, to eliminate interference with fasteners.

Paragraph I.A., Effectivity, shows changes of airplane operators. Each operator should examine the

Effectivity paragraph for changes.

Vertical lines are put on the left edge of each page, except in Paragraph I.A., Effectivity, to show the location

of important changes.

Pages with a revision number and date, but no vertical lines, have no important changes.

REVISION HISTORY

Initial Release: June 30, 1994

Revision 1: May 25, 1995

BOEING COMMERCIAL AIRPLANE GROUP P.O. BOX 3707 SEATTLE, WASHINGTON 98124-2207

Commercial

Airplane

Group

737

Service Bulletin

Number: 737-53A1166 Summary Date: June 30, 1994

Revision 1: May 25, 1995

ATA System: 5311

SUBJECT: FUSELAGE - FRAMES - BODY STATION 727 OUTBOARD CHORD AT STRINGER 18A,

INSPECTION AND PREVENTIVE MODIFICATION

BACKGROUND

Four operators sent reports of cracks in the

outboard chord of the frame at Body Station (BS)

727 where Stringer 18A is attached. The reports

were of eight airplanes with 39,000 to 54,100 flight

hours and 56,200 to 73,200 flight cycles. The

cracks were caused by fatigue that was started by

fretting of adjacent parts. Operators have also sent

reports of cracks in the outboard chord of Stringer

18-A.

The changes shown in this service bulletin will

decrease the probability of these cracks. This area

is a primary structural element. Operation with

cracks in the frame will decrease the structural

integrity of this area.

As part of a service bulletin validation program, the

inspection, frame chord replacement, and preventive

modification was completed on airplane PG576

(Group 2) before the initial release of this bulletin.

ACTION

Make an inspection of the outboard chord of the

frame at BS 727 where Stringer 18A is attached.

Look for cracks. Do the inspection at the times

given in the Compliance section.

Also, make an inspection of the outboard chord of

Stringer 18A at Station 727. If cracks are found in

the outboard chord of Stringer 18A, do the repair.

If cracks are found in the outboard chord of the

frame at BS 727, install the time limited repair or

replace the chord and, optionally, install the

preventive modification. If no cracks are found,

install the preventive modification or do the

inspection again. Do the inspection at the times

given in the Compliance section until the preventive

modification is installed. If the preventive

modification is installed, no more inspections per

this bulletin are necessary.

More work is necessary for operators that have

replaced the outboard chord of the frame at BS 727

as shown in Service Bulletin 737-53-1088. Refer to

Compliance.

COMPLIANCE

This bulletin has a Flight Safety Inspection Program

that is the minimum necessary to keep the structural

integrity of the outboard chord.

For airplanes with 27,000 flights to 50,000 flights, do

the inspection initially within 4,500 flights after you

get this bulletin. Do the inspection again at intervals

of 15,000 flights until the airplane collects more than

50,000 flights.

For airplanes with 50,000 flights to 60,000 flights, do

the inspection initially within 2,500 flights after you

get this bulletin. Do the inspection again at intervals

of 7,500 flights until the airplane collects more than

60,000 flights.

For airplanes with 60,000 flights to 70,000 flights, do

the inspection initially within 1,500 flights after you

get this bulletin. Do the inspection again at intervals

of 5,000 flights until the airplane collects more than

70,000 flights.

For airplanes with more than 70,000 flights, do the

inspection initially within 500 flights after you get this

bulletin. Do the inspection again at intervals of

3,000 flights.

For airplanes with the lower part of the chord

replaced by SB 737-53-1088, do the inspection at

the intervals shown above.

For airplanes with the upper part of the chord

replaced by SB 737-53-1088, do the inspection

initially within 30,000 flight cycles after the chord

was replaced. Do the inspection again at the

intervals shown above for flight cycles after the

chord was replaced.

BOEING COMMERCIAL AIRPLANE GROUP P.O. BOX 3707 SEATTLE, WASHINGTON 98124-2207 Summary Page 1 of 2
BOEING SERVICE BULLETIN 737-53A1166

EFFECTIVITY

All 737-100 and 737 -200 airplanes, Line Numbers

1-999, in 4 groups.

MANPOWER

Refer to Paragraph I.F. Manpower.

MATERIAL INFORMATION

Boeing Supplied Kits

Refer to Paragraph I.G., Material - Price and

Availability.

EDGE OF FLANGE

EXAMINE FORWARD

AROUND TWO FASTENER HEADS

EXAMINE SURFACE OF S-18A

EXAMINE AREA AROUND

TWO FASTENER HOLES

A FLAT STRAP)

THE OUTER CHORD OF

STRINGER 18-A IS

STRINGER 18-A

(ON SOME AIRPLANES

TYPICAL

CRACK

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

(WING-TO-BODY FAIRING NOT SHOWN)

STA

727

C79178

Jun 30/94

REV 1: May 25/95 Summary Page 2 of 2
Commercial

Airplane

Group

737

Service Bulletin

Number: 737-53A1166

Date: June 30, 1994

Revision 1: May 25, 1995

ATA System: 5311

SUBJECT: FUSELAGE - FRAMES - BODY STATION 727 OUTBOARD CHORD AT STRINGER 18A,

INSPECTION AND PREVENTIVE MODIFICATION

THIS SERVICE BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN

IN PARAGRAPH I.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS

SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND

THIS SERVICE BULLETIN TO THE NEW OWNER.

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 Number data.

This service bulletin is for the airplanes shown below.

IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER

AER LINGUS (ARL)

2 PY322

3 PK641-PK642

AERO CONTROLS, INC (AEO)

2 PG629

AERO COSTA RICA (AOR)

3 PK872-PK873

AEROLINEAS ARGENTINAS (ARG)

2 PH705-PH708 PH741-PH742 PY007

3 PH743 PK102-PK103 PK464

AIR ALGERIE (ALG)

3 PK361 PK631 PK633-PK634 PL717-PL725 PY051 PY053

AIR ATLANTA ICELANDIC (AID)

2 PY346

AIR FOYLE LTD. (FOY)

3 PJ108 PJ113

AIR FRANCE (AFA)

3 PL502-PL503 PN101-PN112

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BOEING SERVICE BULLETIN 737-53A1166

AIR GABON S.A. (GBN)

3 PY191

AIR GUINEE (GNE)

3 PY651

AIR MADAGASCAR (MAD)

2 PG375

3 PL793

AIR NEW ZEALAND, LTD. (ANZ)

3 PJ117-PJ119 PK214 PL621-PL623 PY741

AIR SOUTH, INC. (SOT)

2 PG210 PG215

3 PK221 PK351 PK353 PK462 PK466

AIR TANZANIA (TNZ)

3 PY611-PY612

AIR TOULOUSE INTERNATIONAL (TOL)

2 PL716

AIR UKRAINE (UKA)

3 PK354

AIR ZAIRE (ZAI)

3 PY111 PY113

AIRCORP (CRP)

2 PG037

AIRTRAN AIRWAYS, INC. (CQT)

2 PG438

3 PK028

ALASKA AIRLINES (ASA)

3 PY112 PY134-PY135 PY270 PY461-PY462

ALBATROS AIRLINES (ABS)

2 PG251 PG253

ALIADRIATICA (ADH)

3 PK432

ALL NIPPON AIRWAYS CO. LTD. (ANA)

2 PG584-PG586

3 PK711-PK716

ALOHA (ALO)

2 PG046

3 PK286-PK287 PK691-PK695 PY231 PY242 PY451

AMC AVIATION (AMF)

3 PK254

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BOEING SERVICE BULLETIN 737-53A1166

AMERICA WEST AIRLINES, INC. (AMW)

2 PC004 PG036 PL801

3 PK283 PK696 PL081 PL172 PL551-PL562

AMERICANA DE AVIATION S. A. (AMY)

2 PG276

AMIRI FLIGHT (ABD)

3 PK495

AMORA FLIGHT CHARTER SERVICES (FCA)

2 PG047

ANGOLA AIR CHARTER (AOH)

2 PG431

ANGOLA AIRLINES (ANG)

3 PK661 PK664 PY162

ANSETT WORLDWIDE AVIATION SERVICES (AWW)

1 PA001 PA003-PA004

ARAMCO ASSOCIATED CO. (ARM)

3 PL151 PY241 PY243-PY244

ARKIA ISRAELI AIRLINES, LTD (ARK)

2 PG575

ASEAN AVIATION (L) INC. (ASJ)

2 PG578-PG583

3 PK920

AVENSA (AVN)

3 PK042-PK043

AVIATECA (AVT)

2 PL736-PL737 PL740-PL741

AVIOGENEX AIR TRANSPORT (AVG)

3 PL501 PL506

BOURAQ INDONESIA AIRLINES (PTB)

2 PL742

3 PK501 PK913 PK918 PK931 PL743-PL744

BRITISH AIRWAYS (BAB)

3 PK731-PK749 PK771-PK772 PK774-PK777 PK779

CALDWELL AIRCRAFT TRADING CO. (CAS)

2 PG402

CAMBODIAN INTERNATIONAL AIRLINES (CAK)

2 PJ072

CAMEROON AIRLINES (CAM)

2 PY046-PY047

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BOEING SERVICE BULLETIN 737-53A1166

CANADIAN AIRLINES INTERNATIONAL LTD. (CDI)

2 PY303-PY304

3 PK358 PK671-PK675 PK677-PK680 PK822 PK881 PK884

PL401-PL417 PL764-PL770 PM141-PM142 PY151-PY154 PY421-PY422 PY441

CANAIR CARGO (CAZ)

3 PK026-PK027

CARNIVAL AIR (CVL)

2 PG305 PG312 PL712

3 PJ007-PJ008

CASINO EXPRESS (CIN)

2 PG279 PG436

3 PK461

CAYMAN AIRWAYS (CAY)

3 PJ009 PK222

COMAIR (CML)

2 PG353-PG354 PG356

3 PK355

CONSOLIDATED PRESS HOLDINGS (CPH)

3 PJ109

CONTINENTAL AIRLINES, INC. (CAL)

1 PA006-PA009 PA011 PG199

2 PA012 PA014 PA016-PA020 PG056 PG064 PG225

PG433 PG501-PG505 PG621-PG625 PG627-PG628 PG630 PG704

3 PL001

COPA COMPANIA PANAMENA DE AVIATION S.A. (COP)

2 PY341

3 PJ107 PJ112 PK465 PK617 PL745 PY201

CROATIA AIRLINES (CRH)

3 PK904 PK906-PK907 PK928 PK932

DAMANIA AIRWAYS LTD. (DAI)

3 PL451-PL452 PN081-PN082

DELTA AIR LINES, INC. (DAL)

3 PK611 PK613 PK623-PK624 PL221

4 PN131-PN135

E G AND G (EGN)

3 PL763

E-SYSTEMS (ESM)

2 PG208

EAS EUROPE AIRLINES (EUR)

3 PK203 PK215 PK282 PK359 PK564 PK612

EAST WEST AIRLINES (INDIA) (BOM)

3 PK615-PK616 PK819 PK824 PL171

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BOEING SERVICE BULLETIN 737-53A1166

EDRESS, SHIEKH M. (SME)

3 PL505

EGYPTAIR (EGP)

3 PK255 PK257-PK258

EL AL ISRAEL AIRLINES, LTD. (ELA)

3 PL631-PL632

EURALAIR (ERA)

2 PG026 PG028-PG029 PY004 PY006

FAR EASTERN AIR TRANSPORT (FAT)

1 PA002 PA005

2 PG055 PG226 PG228 PG230

3 PK562

FAUCETT (COMPANIA DE AVIATION S.A. (FCT)

2 PC002 PG034 PG213 PL711

3 PK241 PL758

FLIGHTSTAR AVIATION CORPORATION (FST)

2 PG274

FRENCH POSTAL OFFICE (FPO)

2 PY302 PY344

3 PY101-PY103

FRONTIER AIRLINES (FRO)

2 PG304 PG306 PG308 PG310-PG311

GARUDA INDONESIAN AIRWAYS (GIA)

3 PK917 PK929-PK930

GATARI AIR SERVICE (GRI)

3 PL441

GB AIRWAYS (GBA)

3 PJ110-PJ111

GE CAPITAL AVIATION SERVICES, INC. (GEH)

1 PG272

2 PG218-PG219 PG651-PG652

GOVERNMENT OF BRAZIL (BRZ)

3 PK068-PK069

GOVERNMENT OF MEXICO (MXG)

2 PC005 PG223

GOVERNMENT OF SHARJAH (SHJ)

3 PL581

GPA GROUP LTD. (GUI)

3 PK252 PK614

GULF AIR (GUL)

3 PK467-PK468

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BOEING SERVICE BULLETIN 737-53A1166

HAPAG LLOYD (HAP)

3 PL504

INDIAN AIR FORCE (IDF)

2 PH712-PH713

4 PM016-PM017

INDIAN AIRLINES (IND)

2 PH709 PH711

3 PH021 PH024 PK231-PK233 PK235-PK240 PM001-PM006 PY631

INDONESIAN AIR FORCE (IDO)

3 PL601-PL602

4 PL603

INTEGRATED RESOURCES (INH)

1 PG271

2 PG273 PG403

3 PK697

INTERNATIONAL AIR LEASES (IAL)

2 PG048 PJ001

INTERNATIONAL AIRLINE SUPPORT GROUP (ASG)

2 PG021

INTERNATIONAL PACIFIC TRADING CO. (IPT)

2 PG572 PG574 PJ102

IRAN AIR (IRN)

2 PH731 PY021

3 PK391 PY022

IRAQI AIRWAYS (IRQ)

3 PY141-PY142

JAPAN TRANSOCEAN AIR CO., LTD. (SWL)

3 PK521 PK523-PK525

JETALL HOLDING CORPORATION (JEL)

2 PY002 PY005

KENYA AIRWAYS (KEN)

3 PK253 PK256

LACSA (LAC)

3 PK357 PK871

LADECO (LDE)

2 PL802

3 PJ004-PJ006 PK029 PK212 PK281 PK826 PK830

LAN-CHILE S.A. (LAN)

3 PK360 PK825 PL025-PL026 PL028

LAPA (LAZ)

2 PG355

3 PK047 PK051 PK463

Jun 30/94 737-53A1166

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BOEING SERVICE BULLETIN 737-53A1166

LINA CONGO (LNA)

3 PY411

LINHAS AEREAS DE MOZAMBIQUE (LAM)

2 PH703 PY031

LITHUANIAN AIRLINES (LIJ)

3 PK563

LUFTHANSA GERMAN AIRLINES (DLH)

2 PY345

3 PK901-PK903 PK911-PK912 PK914-PK916 PK919 PK921-PK923 PK926-PK927

MAGNICHARTERS (MAM)

2 PG224

3 PJ003

MALEV HUNGARIAN AIRLINES (HGA)

3 PK284-PK285 PK636-PK637 PK827

MANDALA AIRLINES (MND)

3 PK874 PK924-PK925 PL027 PL061 PL421 PN002

MARKAIR, INC. (ALK)

3 PK632 PL611

4 PY056-PY057

MODILUFT (MOU)

3 PK905 PK908-PK910

MONTELY II (MOY)

2 PJ031

NASA (NAS)

1 PA099

NATIONAL AIRLINES (NAW)

2 PJ104

3 PJ105-PJ106

NICA (NICARAGUENCE DE AVIACION) (NIC)

3 PK823

NIGERIA AIRWAYS, LTD. (NIA)

3 PL781-PL782 PL785-PL788

NORDIC EAST (NOE)

2 PJ002

NWT AIR (NTA)

2 PX701

3 PY132-PY133 PY281

OLYMPIC AIRWAYS (OLY)

3 PK301-PK304 PK307-PK310 PM021-PM023

P. T. AIRFAST (PTF)

2 PG204 PG278 PY343

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BOEING SERVICE BULLETIN 737-53A1166

PETROLAIR SYSTEMS S. A. (PTS)

3 PL471

PLUNA (PLU)

3 PL201-PL203

PRESIDENTIAL AIR (PRB)

2 PC003

REPUBLIC OF NIGER (NIR)

3 PY166

ROYAL AIR MAROC (RAM)

3 PK271-PK274 PY671

4 PY672

RYANAIR (RYR)

3 PJ114-PJ115 PK503 PK801-PK804 PN001

SABENA S.A. (SAB)

3 PK041 PK044-PK046 PK048-PK050 PK052-PK053 PK431 PK433

PY272-PY275

SAETA S.A. (SAE)

3 PK211 PK561

SAHARA INDIAN AIRLINES (SAQ)

3 PK820

SAHSA (SERVICIO AEREO DE HONDURAS,S.A.) (SAH)

2 PJ071

SAKHALIN AIRLINES (SKH)

2 PG214

SAUDI ARABIAN AIRLINES CORP. (SVA)

2 PL726-PL728 PY036-PY037

3 PK311-PK317 PL729-PL735

SAUDI ROYAL FLIGHT (SRF)

3 PK318

SERVICIOS AEREOS RUTAS ORIENTE, (SARO) (SEV)

2 PA015 PA021-PA022 PJ032

SHAHEEN AIR INTERNATIONAL (SHK)

3 PK514

SHANNONAIR LEASING LTD. (SLE)

3 PK352

SIERRA PACIFIC AIRLINES (SRP)

3 PK627

SOUTH AFRICAN AIRWAYS (SAA)

3 PL101-PL113

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BOEING SERVICE BULLETIN 737-53A1166

SOUTHWEST AIRLINES CO. (SWA)

3 PK082 PK091-PK099 PK541-PK560 PK621 PK628-PK630 PM051-PM062

SUDAN (SUD)

3 PY156-PY157

T A PORTUGUESES (TAP)

3 PK971 PK973-PK974 PN083

4 PN084-PN086

TACA INTERNATIONAL AIRLINES, INC. (TAC)

2 PG059 PG352

3 PK213 PK223 PK882 PY131

TAESA (TES)

3 PK622 PK625-PK626

TAT EUROPEAN AIRLINES (TTR)

2 PY003 PY301 PY321 PY361-PY362

THAI AIR FORCE (TAF)

4 PK519

THAI AIRWAYS INT'L PUBLIC CO., LTD. (TII)

3 PK511

TITAN CHARTER AVIATION INC. (TCA)

2 PL761

3 PL762

TRANSAERO (TRX)

3 PK451-PK452 PK773

TRANSAVIA AIRLINES (TAV)

2 PG074

3 PK502 PK504 PK821

TRANSMILE AIR SERVICES (TML)

2 PY323 PY342 PY381

TUNISAIR (TUN)

3 PK861-PK863 PY621

UKRAINE INTERNATIONAL AIRLINES (UKR)

3 PK635

UNITED AIR LINES, INC. (UAL)

1 PG001-PG004 PG006-PG008

2 PG009-PG013 PG015-PG019 PG022-PG025 PG027 PG030 PG032

PG038-PG040 PG045 PG051-PG054 PG057 PG060-PG063 PG065-PG072

PG075

3 PK201-PK202 PL002-PL023

UNITED STATES AIR FORCE (USF)

3 PJ201-PJ219

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BOEING SERVICE BULLETIN 737-53A1166

USAIR, INC. (USA)

2 PG073 PG301 PG303 PG307 PG313-PG314 PG474

3 PK288-PK289 PK591-PK599 PK601-PK610 PK883 PM101-PM117 PN021-PN028

4 PM118-PM119 PN029-PN038

USL CAPITAL (USL)

2 PY001

VANGUARD AIRLINES (VAG)

2 PG041-PG042 PG206 PG576 PL803

VARIG AIRLINES (VAR)

3 PK111-PK116 PK118-PK120 PK141-PK146 PL453-PL454

VARSA (VAB)

2 PG351

VASP (VSP)

2 PG435 PG437 PG439-PG440 PG471-PG473 PL756 PX071

3 PH011-PH013 PK061-PK062 PK065-PK067 PK356 PK581 PY286

VENEZUELA - GOVERNMENT OF (VNZ)

3 PK070

VISCOUNT AIR SERVICE INC. (VAS)

2 PG201 PG203 PG209 PG212 PG216-PG217 PG220-PG222

PJ101 PJ103

3 PK305-PK306

YEMEN AIRWAYS (YEM)

3 PK341

ZAMBIA AIRWAYS (ZAM)

3 PK291

IDENTIFICATION BY VARIABLE NUMBER

GROUP 1

PA001-PA011 PA099 PG001-PG008 PG199 PG271-PG272

GROUP 2

PA012-PA022 PA231-PA232 PC001-PC005 PG009-PG075 PG201-PG230 PG251-PG255

PG273-PG279 PG301-PG314 PG331-PG332 PG351-PG356 PG375 PG401-PG403

PG431-PG442 PG471-PG475 PG501-PG505 PG571-PG586 PG621-PG630 PG651-PG652

PG701-PG705 PH701-PH715 PH731-PH732 PH741-PH742 PJ001-PJ002 PJ031-PJ032

PJ071-PJ072 PJ101-PJ104 PL711-PL712 PL716 PL726-PL728 PL736-PL742

PL756 PL761 PL801-PL803 PX071 PX701 PY001-PY008

PY021 PY031 PY036-PY037 PY046-PY047 PY301-PY304 PY321-PY323

PY341-PY346 PY361-PY362 PY381

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BOEING SERVICE BULLETIN 737-53A1166

GROUP 3

PH001 PH011-PH013 PH021-PH024 PH743 PJ003-PJ009 PJ105-PJ119

PJ201-PJ219 PK026-PK029 PK041-PK053 PK061-PK070 PK081-PK082 PK091-PK099

PK101-PK103 PK111-PK120 PK141-PK146 PK201-PK204 PK211-PK215 PK221-PK223

PK231-PK241 PK251-PK258 PK271-PK274 PK281-PK289 PK291 PK301-PK318

PK341 PK351-PK361 PK391 PK431-PK433 PK451-PK452 PK461-PK469

PK495 PK501-PK504 PK511-PK514 PK521-PK525 PK541-PK564 PK581

PK591-PK599 PK601-PK617 PK621-PK637 PK641-PK642 PK661-PK664 PK671-PK680

PK691-PK697 PK711-PK716 PK731-PK749 PK771-PK779 PK801-PK804 PK819-PK827

PK830 PK861-PK863 PK871-PK874 PK881-PK884 PK901-PK932 PK971-PK974

PL001-PL028 PL061 PL081 PL101-PL113 PL151 PL171-PL172

PL201-PL203 PL221 PL401-PL417 PL421 PL441 PL451-PL454

PL471 PL491 PL501-PL506 PL551-PL562 PL581 PL601-PL602

PL611 PL621-PL623 PL631-PL632 PL717-PL725 PL729-PL735 PL743-PL745

PL758 PL762-PL770 PL781-PL788 PL793 PM001-PM006 PM021-PM023

PM051-PM062 PM101-PM117 PM141-PM142 PN001-PN002 PN021-PN028 PN081-PN083

PN101-PN112 PY022 PY048 PY051-PY053 PY101-PY103 PY111-PY113

PY131-PY135 PY141-PY143 PY151-PY154 PY156-PY157 PY161-PY162 PY166

PY191 PY201 PY221-PY222 PY231 PY241-PY244 PY270-PY275

PY281 PY286 PY401 PY411 PY421-PY422 PY441

PY451 PY461-PY462 PY611-PY612 PY621 PY631 PY651

PY671 PY741

GROUP 4

PK519 PL603 PM016-PM017 PM118-PM119 PN029-PN038 PN084-PN086

PN131-PN135 PY056-PY057 PY672

2. Spares

None

Jun 30/94 737-53A1166

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BOEING SERVICE BULLETIN 737-53A1166

B. Reason

Boeing Supplemental Structural Inspection Document D6-37089, Section 8.2, SSI Number F.29, is

related to this service bulletin.

Boeing Structural Item Interim Advisory (SIIA) 737-131 is related to this service bulletin.

The changes shown in this service bulletin will decrease the probability of cracks in the frame at Body

Station (BS) 727 where Stringer 18A is attached. This area is a primary structural element.

Operation with cracks in the frame will decrease the structural integrity of this area. Unscheduled

downtime can be necessary to replace a frame that has a crack.

Four operators sent reports of cracks in the outboard chord of the frame at BS 727. The reports were

of eight airplanes with 39,000 to 54,100 flight hours and 56,200 to 73,200 flight cycles. The cracks

were found in the chord at the lower row of fasteners where Stringer 18A is attached. The cracks

were in a forward and aft direction and measured approximately 1.4 to 3.0 inches in length. The

cracks were caused by fatigue that was started by fretting of adjacent parts. Operators have also

sent reports of cracks in the outboard chord of Stringer 18-A.

Revision 1 is sent to add a stringer 18A outer chord repair. In addition, instructions have been added,

to trim "Time Limited Repair" parts, to eliminate interference with fasteners.

As part of a service bulletin validation program, the inspection, frame chord replacement, and

preventive modification was completed on airplane PG576 before the initial release of this bulletin.

Airplane PG576 had the configuration of a Group 2 airplane.

C. Description

The airplane effectivity is divided in 4 groups because of differences in airplane configuration. There

is a preventive modification kit for each of the airplane configurations.

Do the inspections that follow at the times given in the Compliance section.

Make a visual inspection of the edge of the forward flange of the outboard chord of the frame at BS

727. Look for cracks.

Make an inspection of the outboard chord under Stringer 18-A. Use the Pulse Echo Shear Wave

(PESW) Inspection procedure. Look for cracks in the area of the two forward lower fastener holes in

the chord where Stringer 18A is attached.

NOTES:

1. Airplanes with 60,000 to 70,000 cycles can omit the next step only at the initial inspection at

1500 flights after you get this bulletin.

2. Airplanes with more than 70,000 cycles can omit the next step only at the initial inspection at

500 flights after you get this bulletin.

Remove the two forward lower fasteners. Make an inspection of the fastener holes in the outboard

chord of BS 727. Use a high frequency eddy current (HFEC) inspection procedure. Look for cracks.

Also, make an inspection of the outboard surface of the outboard chord of Stringer 18A at Station

727. Examine the surface around the heads of two fasteners. Use a high frequency eddy current

(HFEC) inspection procedure. Look for cracks. If cracks are found in the outboard chord of Stringer

18A, do the repair.

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BOEING SERVICE BULLETIN 737-53A1166

If cracks are found in the outboard chord of the frame at BS 727, install the time limited repair or

replace the chord. Refer to Boeing Service Bulletin 737-53-1088 for instructions to replace the chord.

When you replace the chord, Boeing recommends that you also install the preventive modification.

At the operators option, the preventive modification can be installed later.

The repair is time limited. Within 4500 flight cycles, but not more than 18 months, after the repair was

installed, replace the chord as specified in Boeing Service Bulletin 737-53-1088. The repair chord

takes the place of the forward splice angle of the chord replacement kit per Service Bulletin

737-53-1088. When you replace the chord, Boeing recommends that you also install the preventive

modification. At the operators option, the preventive modification can be installed later.

If no cracks are found, install the preventive modification or repeat the inspection at the times given in

the Compliance section until the preventive modification is installed.

If the preventive modification is installed, no more inspections, per this service bulletin, are

necessary.

More work is necessary for operators that have replaced the chord as shown in Service Bulletin

737-53-1088. Refer to the Compliance section.

Revision 1 - no more work is necessary on airplanes changed as shown in the initial release of this

service bulletin.

An evaluation form is attached to this service bulletin. Please use this form to tell us what you think

of the quality of this service bulletin.

NOTES:

1. The changes given in Boeing Service Bulletin 737-53A1039, "Fuselage - Skin Lap Joint

Inspection and Repair", can be made on applicable airplanes before or during the changes

given in this service bulletin.

2. The changes given in Boeing Service Bulletin 737-53-1066, "Fuselage - Stringer 18A Shear

Beam Inspection, Repair and Modification", can be made on applicable airplanes before or

during the changes given in this service bulletin.

3. The changes given in Boeing Service Bulletin 737-53-1076, "Fuselage - Circumferential Butt

Splices and Bonded Doublers Inspection, Repair and Modification", can be made on applicable

airplanes before or during the changes given in this service bulletin.

4. The changes given in Boeing Service Bulletin 737-53-1077, "Fuselage - Skin Inspection,

Repair, and Modification Aft of Body Station 727 Between Stringer S-18 and S-21", can be

made on applicable airplanes before or during the changes given in this service bulletin.

5. The changes given in Boeing Service Bulletin 737-53-1089, "Fuselage - Skin Cracks at Stringer

17 Inspection and Preventive Modification", can be made on applicable airplanes before or

during the changes given in this service bulletin.

6. The changes given in Boeing Service Bulletin 737-53-1124, "Fuselage - Bonded Doublers

(Tear Straps) - Inspection and Repair - For Delamination above Stringer 26 Between Stations

259 and1016", can be made on applicable airplanes before or during the changes given in this

service bulletin.

PLEASE SEND A REPORT OF YOUR INSPECTION PROGRAM. ALSO, SEND THE INSPECTION

RESULTS WHEN EACH INSPECTION IS COMPLETE. REFER TO THE FLIGHT SAFETY SECTION

IN THE ADDENDUM.

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BOEING SERVICE BULLETIN 737-53A1166

D. Compliance

This bulletin has a Flight Safety Inspection Program that is the minimum necessary to keep the

structural integrity of the outboard chord.

For airplanes with 27,000 flights to 50,000 flights, do the inspection initially within 4,500 flights after

you get this bulletin. Do the inspection again at intervals of 15,000 flights until the airplane collects

more than 50,000 flights.

For airplanes with 50,000 flights to 60,000 flights, do the inspection initially within 2,500 flights after

you get this bulletin. Do the inspection again at intervals of 7,500 flights until the airplane collects

more than 60,000 flights.

For airplanes with 60,000 flights to 70,000 flights, do the inspection initially within 1,500 flights after

you get this bulletin. Do the inspection again at intervals of 5,000 flights until the airplane collects

more than 70,000 flights.

For airplanes with more than 70,000 flights, do the inspection initially within 500 flights after you get

this bulletin. Do the inspection again at intervals of 3,000 flights.

For airplanes with the lower part of the chord replaced by Service Bulletin 737-53-1088, do the

inspection at the intervals shown above.

For airplanes with the upper part of the chord replaced by Service Bulletin 737-53-1088, do the

inspection initially within 30,000 flight cycles after the chord was replaced. Do the inspection again at

the intervals shown above for flight cycles after the chord was replaced.

Federal Aviation Administration (FAA) Notice of Proposed Rule Making, FAA Docket Number

94-NM-159-AD, is related to this service bulletin.

E. Approval

This service bulletin was examined by the Federal Aviation Administration (FAA). The changes

specified in this service bulletin comply with the applicable Federal Aviation Regulations (FAR) and

are FAA approved. The service bulletin and the FAA approval were based on the airplane in its

original Boeing delivery configuration or as modified by other FAA 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.

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BOEING SERVICE BULLETIN 737-53A1166

F. Manpower

The data below shows an estimate of the man-hours necessary to do the inspection, repair, and

preventive modification for each airplane. This estimate is for direct labor only, done by an

experienced crew. Adjust the estimate with operator man-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 make the parts

- Time to find the tools.

Inspection:

Task Number of Persons Man-Hours Elapsed Time (Hours)

Open Access 1 1 1

Inspection 1 1.5 1.5

Close Access 1 1 1

TOTAL FOR INSPECTION 3.5 3.5

Time Limited Repair for the Outer Chord of BS 727 Frame.

Task Number of Persons Man-Hours Elapsed Time (Hours)

Open Access 2 6 3

Install Repair 2 30 15

Close Access 2 6 3

TOTAL FOR REPAIR 42 21

Preventive Modification.

Task Number of Persons Man-Hours Elapsed Time (Hours)

Open Access 2 32 16

Preventive

Modification

2 40 20

Close Access 2 27 13.5

TOTAL FOR MODIFICATION 99 49.5

Stringer 18A Repair

Task Number of Persons Man-Hours Elapsed Time (Hours)

Open Access 2 8 4

Install Repair 2 26 13

Close Access 2 8 4

TOTAL FOR REPAIR 42 21

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BOEING SERVICE BULLETIN 737-53A1166

G. Material - Price and Availability

Boeing can supply the kits shown in Paragraphs II.A., Parts Necessary For Each Airplane as shown

below. Kit availability is shown in the Reorder Lead Time (ROLT). ROLT is calculated from the date

Boeing gets the purchase order.

Kit Number Name

ROLT

(weeks)

Unit Price thru

Jan 26/96

65C37277-1 Top Kit, Left Side 32 $1759

65C37277-2 Top Kit, Right Side 32 $1759

65C37277-3 Top Kit, Left Side 32 $1825

65C37277-4 Top Kit, Right Side 32 $1825

65C37277-5 Top Kit, Left Side 32 $1840

65C37277-6 Top Kit, Right Side 32 $1840

65C37277-7 Top Kit, Left Side 32 $1805

65C37277-8 Top Kit, Right Side 32 $1805

65C37565-1 (a) Top Kit, Left Side 36 $1460

65C37565-2 (a) Top Kit, Right Side 36 $1460

65C37565-3 (a) Top Kit, Left Side 36 $1460

65C37565-4 (a) Top Kit, Right Side 36 $1460

65C37565-5 (a) Top Kit, Left Side 36 $1631

65C37565-6 (a) Top Kit, Right Side 36 $1631

65C37565-7 (a) Top Kit, Left Side 36 $1631

65C37565-8 (a) Top Kit, Right Side 36 $1631

(a) As an option, instructions to make theStringer 18A repair parts are provided in

Figure 6 of this service bulletin.

The kits are subject to the terms and conditions of the Boeing standard purchase order

acknowledgment. After the Unit Price date, new price (and ROLT ) data 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 - Price and Availability

None

I. Weight and Balance

Task

Change in Weight

(Pounds)

Change in Moment

(Pound-Inches)

Preventive Modification +3.70 +2690

Time Limited Repair +6.50 +4755

Stringer 18A Repair:

Repair Kit 65C37565-1,-2,-3,-4 (a) +1.52 +1105

Repair Kit 65C37565-5,-6,-7,-8 (b) +1.90 +1381

(a) For airplanes without the preventive modification installed.

(b) For airplanes with the preventive modification installed.

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BOEING SERVICE BULLETIN 737-53A1166

J. References

1. Existing Data:

a. 737 Maintenance Manual Subjects 26-21-11, 27-51-261, 53-23-1

b. 737 Structural Repair Manual Subjects 51-10-1, 51-10-2, 51-20-1, 51-20-4

c. 737 Nondestructive Test Manual D6-37239, Part 4, Subject 53-10-01

d. 737 Nondestructive Test Manual D6-37239, Part 6, Subject 51-00-00, Figure 1

e. 737 Maintenance Planning Data Manual D6-17594-2, Section 6-02

f. Boeing Service Bulletin 737-53-1088, "Fuselage - Body Station 727 Bulkhead, Outboard Chord

Inspection and Replacement"

2. Data supplied with this service bulletin:

a. Drawings:

Drawing Number Sheet DCN ADCN Title

65C37277 PL - 1 Strap Installation - Station 727 Bulkhead,

1 - - S-18 to S-20, Preventive Modification (Top Kit)

65C37565 PL (a) A - Strap Installation - S-18A Outboard Chord

1 (a) - - Repair - Station 727

(a) Sent with Revision 1.

3. Installation Drawings:

Drawing Number Title

65-48654 Frame Installation - Aft Wing/Body Fairing, Station 729.38

65-46877 Strap and Beam Installation - Stringer 18A, Station 639 to Station 747

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.

4. Process Data:

Boeing Process Specifications referred to on the drawings are not given in this service bulletin

since these procedures are frequently used as standard shop practices.

Jun 30/94 737-53A1166

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BOEING SERVICE BULLETIN 737-53A1166

K. Publications Changed

Publication Chapter-Section

737 Structural Repair Manual 53-10-2

737 Non-Destructive Test Manual Part 4

L. Electrical Load Data

Not changed

Jun 30/94 737-53A1166

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BOEING SERVICE BULLETIN 737-53A1166

II. MATERIAL INFORMATION

A. Parts Necessary For Each Airplane

1. To get the kits shown below, refer to Paragraph I.G., Material - Price and Availability.

NOTES:

1. One Preventive Modification Kit and if required, one S-18A Repair Kit, and the operator

supplied materials specified in Paragraph II.A.2., Parts and Materials Supplied by the

Operator, are necessary for each side of the airplane.

2. As an option, the Stringer 18A repair parts, included in the 65C37565 Repair Kits, can be

made by the operator. Refer to Figure 6.

65C37277 - STRAP INSTALLATION - STATION 727 BULKHEAD, S-18 TO S-20,

PREVENTIVE MODIFICATION (TOP KIT)

-4 -3 -2 -1

Quantity Part Number Name

. . . - 65C37277-1 (a) (e) Preventive Modification Kit (Left Side)

. . - . 65C37277-2 (a) (e) Preventive Modification Kit (Right Side)

. - . . 65C37277-3 (b) (e) Preventive Modification Kit (Left Side)

- . . . 65C37277-4 (b) (e) Preventive Modification Kit (Right Side)

65C37277 - STRAP INSTALLATION - STATION 727 BULKHEAD, S-18 TO S-20,

PREVENTIVE MODIFICATION (TOP KIT)

-8 -7 -6 -5

Quantity Part Number Name

. . . - 65C37277-5 (c) (e) Preventive Modification Kit (Left Side)

. . - . 65C37277-6 (c) (e) Preventive Modification Kit (Right Side)

. _ . . 65C37277-7 (d) (e) Preventive Modification Kit (Left Side)

- . . . 65C37277-8 (d) (e) Preventive Modification Kit (Right Side)

65C37565 - STRAP INSTALLATION - STATION 727 BULKHEAD, S-18A OUTBOARD

CHORD REPAIR (TOP KIT)

-4 -3 -2 -1

Quantity Part Number Name

. . . - 65C37565-1 (b) (f) (h) Repair Kit (Left Side)

. . - . 65C37565-2 (b) (f) (h) Repair Kit (Right Side)

. - . . 65C37565-3 (c) (f) (h) Repair Kit (Left Side)

- . . . 65C37565-4 (c) (f) (h) Repair Kit (Right Side)

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BOEING SERVICE BULLETIN 737-53A1166

65C37565 - STRAP INSTALLATION - STATION 727 BULKHEAD, S-18 TO S-20,

PREVENTIVE MODIFICATION (TOP KIT)

-8 -7 -6 -5

Quantity Part Number Name

. . . - 65C37565-5 (b) (g) (h) Repair Kit (Left Side)

. . - . 65C37565-6 (b) (g) (h) Repair Kit (Right Side)

. _ . . 65C37565-7 (c) (g) (h) Repair Kit (Left Side)

- . . . 65C37565-8 (c) (g) (h) Repair Kit (Right Side)

a. For Group 1 airplanes.

b. For Group 2 airplanes.

c. For Group 3 airplanes.

d. For Group 4 airplanes.

e. Refer to Drawing 65C37277, sent with the initial release of this bulletin, for the list of parts.

f. For airplanes without the 65C37277 Preventive Modification installed.

g. For airplanes with the 65C37277 Preventive Modification installed.

h. Refer to Drawing 65C37565, sent with this bulletin, for the list of parts.

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BOEING SERVICE BULLETIN 737-53A1166

2. Parts and Materials Supplied by the Operator for the Preventive Modification:

Quantity Part Number (Specification) Name

As necessary BMS 5-92, or equivalent Adhesive

As necessary BMS 5-95, or equivalent Sealant

As necessary BMS 10-11, Type 1, or equivalent Primer

As necessary BMS 10-11, Type 2, or equivalent,

Color BAC702 White

Gloss Enamel

3. Parts and Materials Supplied by the Operator if the Preventive Modification is not installed:

NOTE: Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners.

Quantity Part Number (Specification) Name

2 BACB30MB8A( ) (a) (b) (e) Hi-Lok

2 BACB30MC8A( ) (a) (c) (e) Hi-Lok

2 BACC30X8 (a) (b) (c) Collar

2 BACB30MD8A( ) (a) (d) (e) Hi-Lok

2 BACC30AC8 (a) (d) Collar

(a) Use if the chord is not replaced and the preventive modification is not installed. Use oversize

fasteners if necessary (refer to III. Accomplishment Instructions). Only two fasteners are

necessary at each installation. Choose the appropriate size.

(b) Standard size.

(c) For 1/64 oversize.

(d) For 1/32 oversize.

(e) Choose the grip length the same as the fastener that is removed. Refer to Figure 1.

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BOEING SERVICE BULLETIN 737-53A1166

4. Parts and Materials Supplied by the Operator for the Time Limited Repair:

The table that follows shows the repair parts necessary at each installation.

NOTE: Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners.

Quantity Part Number (Specification) Name

1 4x8x 0.15 inch thick 7075-T0 Aluminum Alloy Sheet

1 AND10134-2008 x 20.8, 7075-T6

or equivalent

Extruded Angle

1 1.25 x 4.25 x 0.032 inch thick 7075-T6 Aluminum Alloy Sheet

1 1.25 x 6 x 0.18 inch thick 7075-T6 Aluminum Alloy Sheet

1 1.4 x 8.2 x 0.18 inch thick 7075-T6 Aluminum Alloy Sheet

1 2.1 x 11.4 x 0.18 inch thick 7075-T6 Aluminum Alloy Sheet

1 1.2 x 8.7 x 0.18 inch thick 7075-T6 Aluminum Alloy Sheet

1 1.2 x 1.4 x 0.82 inch thick 7075-T6 Aluminum Alloy Sheet

As necessary BMS 5-95, or equivalent Sealant

As necessary BMS 10-11, Type 1, or equivalent Primer

As necessary BACB30MB8A( ) Hi-Lok

As necessary BACC30X8 Collar

B. Parts Necessary to Change Spares

None

C. Special Tools and Equipment

No special tools or equipment are necessary to do the change in this service bulletin. Also,

maintenance and overhaul tools in manuals shown in Paragraph I.J., References, can be necessary.

Examine operator tool supply to make sure all necessary tools are available.

D. Existing Parts Accountability

None

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BOEING SERVICE BULLETIN 737-53A1166

III. ACCOMPLISHMENT INSTRUCTIONS

NOTES:

1. The paragraphs identified with letters give the general work instructions and the necessary tests.

The instructions identified with numbers on the figures give the recommended sequence of steps.

2. 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 given in 737 Structural Repair Manual Chapter 51

- Torque limits to tighten nuts and bolts are given in 737 Structural Repair Manual Chapter 51

- Edge margins for fasteners are given in 737 Structural Repair Manual Chapter 51

3. Fastener installation is given in 737 Structural Repair Manual Chapter 51.

4. Alternative fasteners are given in 737 Structural Repair Manual Chapter 51.

5. Obey all of the warnings and cautions given in the specified manual sections.

Part I Flight Safety Inspection Program

A. Do the inspections that follow at the thresholds specified in the Compliance section.

B. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at Body Station (BS)

727 through the opening in the flap fairing. At the operators option, for more access, remove the

fairing for the inboard track of the inboard flap. Keep the fairing and all fasteners for installation.

C. Get access to the inboard side of the frame at BS 727 from inside the wheelwell. On the left side, at

the operators option for more access, disconnect the connectors for the gauge and the detonator on

the aft fire bottle.

D. Examine the outboard surface of the outboard chord of Stringer 18-A. Look for cracks in the surface

around the heads of the two fasteners immediately aft of BS 727. Refer to Figure 1.

E. If there are cracks in the outboard chord of Stringer 18-A, do the repair as specified in Part IV.

F. At the edge of the forward flange of the outboard chord of the frame at BS 727, inspect for cracks.

Refer to Figure 1.

G. If there are no cracks in the forward flange of the outboard chord of the frame at BS 727, go to Step H.

If there are cracks, go to Step L.

H. Use the Pulse Echo Shear Wave Inspection procedure in the area under the outboard chord of

Stringer 18-A. Look for cracks in the area of the two lower fastener holes. Refer to Figure 1.

I. If no cracks are detected by this procedure in the area of the two lower fastener holes in the outboard

chord of the frame at BS 727, go to Step J. If there are cracks, go to Step L.

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BOEING SERVICE BULLETIN 737-53A1166

NOTES:

1. Airplanes with 60,000 to 70,000 cycles can omit Steps J and K only at the initial inspection at

1500 flights after you get this bulletin.

2. Airplanes with more than 70,000 cycles can omit Steps J and K only at the initial inspection at

500 flights after you get this bulletin.

J. Get access to the two lower fasteners in the outboard chord of the frame at BS 727 where Stringer

18A is attached. Refer Figure 1.

K. Remove the two fasteners and inspect the fastener holes for cracks as shown in Figure 1.

L. If cracks are found in the outboard chord of the frame at BS 727, at the customers option install the

time limited repair (refer to Part III of the Accomplishment Instructions) or go to Step M. The time

limited repair is limited to a crack that extends from the forward edge of the chord, or from the forward

fastener hole, but does not extend past the second fastener hole. At the time specified in Part C.

Description, replace the chord. Refer to Step M. The repair chord takes the place of the forward

splice angle of the chord replacement kit per Service bulletin 737-53-1088. If the crack extends past

the second fastener hole go to Step M.

M. Replace the chord as shown in Boeing Service Bulletin 737-53-1088 (refer to Part II of the

Accomplishment Instructions). When you replace the chord, Boeing recommends that you also install

the preventive modification. At the customers option, the preventive modification can be installed

later. If you install the preventive modification, use the hole pattern shown for the chord replacement

(refer to 737-53-1088) to install the 69-78770-1 splice plate. If the preventive modification is not

installed, do the inspections again as specified in the Compliance section.

N. If no cracks are found, install the preventive modification as specified in Part II of the Accomplishment

Instructions or do the inspections again as specified in the Compliance section.

O. If the preventive modification is not installed, replace the fasteners removed in Step K (refer to Figure

1). If necessary, drill 1/64 or 1/32 inch oversize to remove any damage (such as scratches, nicks, or

ovality) in the fastener holes and install oversize fasteners (refer to Section II.A.2. Parts and Materials

Supplied by Operator). Do the inspections again, as specified in the Compliance section, until the

preventive modification is installed.

NOTE: Check the fastener holes before they are oversized to see if they are already oversize by the

incorporation of another service bulletin. If another service bulletin has been installed, use

the same size and type of fastener used in the other service bulletin. If necessary, drill 1/64

or 1/32 inch oversize to remove any damage (such as scratches, nicks, or ovality) in the

fastener holes and install oversize fasteners.

P. If disconnected in Step C, install the connectors for the gauge and the detonator on the aft fire bottle.

Q. If removed in Step B, Install the fairing for the inboard track of the inboard flap.

R. Return the airplane to serviceable condition.

S. Send a report of the inspection to Boeing. Refer to Paragraph C. Description and the Flight Safety

Section in the Addendum.

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BOEING SERVICE BULLETIN 737-53A1166

Part II Preventive Modification

A. Get access to the outboard side of the outboard chord at Body Station (BS) 727 between Stringers

S-17 and S-20. Also, get access to the outboard side of Stringers S-18A and S-19 from BS 709 to BS

747 (for 737 -100 airplanes) or 727A (for 737-200 airplanes). Refer to Figure 2.

To get the access, remove the parts that follow:

. The wing-to-body fairings (refer to AMM 53-51-21).

. The fairing support structure at BS 727 (refer to View A-A in Figure 2).

B. Get access to the inboard side of Stringer S-19 between BS 729 and 747 (for 737 -100 airplanes) or

727A (for 737-200 airplanes). To get the access, remove the cargo liner at the forward end of the

cargo compartment in the aft lower lobe.

NOTE: On some airplanes there may be an auxiliary fuel tank installed. If installed, remove the

auxiliary fuel tank to get access to the cargo liner (refer to 737 AMM 53-23-1).

C. In the wheel well, get access to the inboard side of Stringer S-18A between BS 709 and 727.

D. In the wheel well, get access to the inboard side of the outer chord at BS 727. To get the access,

remove the engine fire extinguisher bottles (refer to 737 AMM 26-21-11).

CAUTION: TO INSTALL THE PREVENTIVE MODIFICATION, SKIN PANEL ATTACHMENT

FASTENERS ARE REMOVED. THIS SKIN PANEL AND FASTENERS ARE THE

SUBJECT OF AIRWORTHINESS DIRECTIVES 88-22-11 R1, 89-09-03, 91-08-12 AND

92-25-09. MAKE SURE THAT THE INCORPORATION OF THIS SERVICE BULLETIN

DOES NOT CHANGE THE COMPLIANCE WITH THESE AIRWORTHINESS

DIRECTIVES.

NOTE: Airworthiness Directives 88-22-11 R1 and 89-09-03 refer to Boeing Service Bulletins

737-53-1039 and 737-53-1089. Airworthiness Directive 91-08-12 refers to Boeing Service

Bulletin 737-53-1124. Airworthiness Directive 92-25-09 refers to Boeing Service Bulletin

737-53-1076.

E. Install the preventive modification as shown in Drawing 65C37277.

NOTES:

1. At the customers option make the external strap, 69-78770-1, -2 opposite, from 4130 150-170

KSI or 15-5PH 150-170 KSI steel.

2. Service Bulletin 737-53-1077 installs a repair patch at BS 727 and Stringer 18A. If the repair

patch is installed, then the 69-78773-10 filler is not needed. If necessary, install an additional

filler forward of BS 727 to match the thickness of the repair patch. If necessary, also use a

tapered filler forward of BS 727, same as the 69-78773-7 tapered filler, but with the thickness

increased to match the repair patch. Keep the same taper ratio.

F. Install the cargo liner if that was removed in Step B. If removed in Step B, install the auxiliary fuel tank

(refer to 737 AMM 53-23-1).

G. Install the engine fire extinguisher bottles removed in Step D (refer to 737 AMM 26-21-11).

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BOEING SERVICE BULLETIN 737-53A1166

H. Install the wing-to-body fairing that was removed in Step A (refer to AMM 53-51-21).

NOTE: The preventive modification installs new structure to replace most of the fairing support

structure that was removed in Step A (refer to Figure 2).

I. Return the airplane to serviceable condition.

Part III Time Limited Repair

A. In the wheel well, get access to the inboard side of the outer chord at BS 727. To get the access,

remove the engine fire extinguisher bottles (refer to 737 AMM 26-21-11).

B. Get access to the aft side of the bulkhead at BS 727. To get the access, remove the cargo liner at the

forward end of the cargo compartment in the aft lower lobe.

NOTE: On some airplanes there may be an auxiliary fuel tank installed. If installed, remove the

auxiliary fuel tank to get access to the cargo liner (refer to 737 AMM 53-23-1).

C. Get access to the forward side of the bulkhead at BS 727. Remove the flap right angle gearbox and

associated brackets (refer to Figure 3).

D. On the forward side of the bulkhead at BS 727, find the horizontal stiffener at approximately Water

Line189. Trim the outboard part of the vertical side of the horizontal stiffener to allow installation of the

repair angle (refer to Figure 3).

E. Trim the aft part of the outboard vertical side of the Stringer S-18A Shear Beam to allow installation of

the repair angle (refer to Figure 3).

F. Drill a stop crack hole at the end of the crack (refer to 737 Structural Repair Manual 51-10-1).

NOTE: To prevent damage to the skin or S-18 structure, put a thin steel shim between the outer

chord at BS 727 and the skin.

G. Make the repair parts (refer to Figure 4).

H. Install the repair parts (refer to Figure 5).

I. Install the flap right angle gearbox and associated brackets removed in Step C (refer to Figure 5).

J. Install the cargo liner removed in Step B. If removed in Step B, install the auxiliary fuel tank (refer to

737 AMM 53-23-1).

K. Install the engine fire extinguisher bottles removed in Step A (refer to 737 AMM 26-21-11).

L. Return the airplane to serviceable condition.

Jun 30/94 737-53A1166

REV 1: May 25/95 26
BOEING SERVICE BULLETIN 737-53A1166

Part IV - Stringer 18A - Outboard Chord Repair

A. Get access to the outboard side of Stringer S-18A, from BS 709 to BS 747 (for 737 -100 airplanes) or

727A (for 737-200 airplanes). Refer to Figure 2.

To get the access, remove the parts that follow:

. The wing-to-body fairings (refer to AMM 53-51-21).

. The fairing support structure at BS 727 (refer to View A-A in Figure 2).

B. In the wheel well, get access to the inboard side of Stringer S-18A between BS 709 and 727.

C. Do the stringer 18A outboard chord repair as specified in drawing 65C37565.

NOTES:

1. Drawing 65C37565 provides repair procedures for airplanes with and without the frame

outboard chord preventive modification installed.

2. The Stringer 18A repair parts can be purchased as Repair Kit 65C37565, refer to Paragraph

I.G., Material - Price and Availability, or, as an option, the Stringer 18A repair parts can be

made by the operator. Refer to Figure 6.

Jun 30/94 737-53A1166

REV 1: May 25/95 27
BOEING SERVICE BULLETIN 737-53A1166

Illustration Table of Contents

Title Page

FIGURE 1. INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION . . . . . . . . . . . . . . . . . . . 32

FIGURE 3. ACCESS FOR THE TIME LIMITED REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . 35

FIGURE 4. MAKE THE TIME LIMITED REPAIR PARTS . . . . . . . . . . . . . . . . . . . . . . . . . 39

FIGURE 5. INSTALL THE TIME LIMITED REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Jun 30/94 737-53A1166

REV 1: May 25/95 28
BOEING SERVICE BULLETIN 737-53A1166

(WING-TO-BODY FAIRING NOT SHOWN)

RIGHT SIDE OPPOSITE

LEFT SIDE SHOWN

SEE DETAIL I

C79635

FIGURE 1. INSPECTION

Jun 30/94 SHEET 1 OF 3 737-53A1166

REV 1: May 25/95 29
BOEING SERVICE BULLETIN 737-53A1166

DETAIL II

2

3 4 5 6

TYPICAL

CRACK

STRINGER 18-A

1

DETAIL I

INBD

FWD

SEE DETAIL II

STRINGER 18-A IS

A FLAT STRAP)

THE OUTER CHORD OF

STRINGER 18-A

(ON SOME AIRPLANES

STA

727

STA

727

C79638

FIGURE 1. INSPECTION

Jun 30/94 SHEET 2 OF 3 737-53A1166

REV 1: May 25/95 30
BOEING SERVICE BULLETIN 737-53A1166

The step number shown below agree with the numbers shown inside the circle symbols in the figure.

STEP TASK NAME PROCEDURE REFERENCES NOTES

1 Examine Outboard chord

of Stringer 18-A

High Frequency

Eddy Current

Inspection

NDT Part 6, 51-00-00,

Figure 4

Examine the outboard

surface of the outboard

chord around the

fastener head. Look for

cracks.

2 Examine Outboard chord

of frame

Close Visual

Inspection

Examine the edge of the

forward flange of the

outboard chord. Look for

cracks.

3 Examine Outboard chord

of frame

Pulse Echo

Shear Wave

Inspection

NDT Part 4, 53-10-01 Examine the area under

the outboard chord of

Stringer 18-A. Look for

cracks.

If there is no indication of a crack, go to Step 4.

STEP TASK NAME PART NUMBER QTY NOTES

4 Remove /

Discard

Lockbolt

Collar

BACB30GW8( )

BACC30K8

2

2

Measure the grip length of the

fastener that was removed.

STEP TASK NAME PROCEDURE REFERENCES NOTES

5 Examine Fastener Holes High Frequency

Eddy Current

Inspection

NDT Part 6, 51-00-00,

Figure 1

Examine the fastener

holes in the forward

flange of the outboard

chord. Look for cracks

If you do not install the preventive modification, go to Step 6.

STEP TASK NAME PART NUMBER QTY NOTES

6 Examine Hole 2 Look for damage.

Drill Oversize

hole

2 If necessary, drill oversize hole

to remove damage. Make sure that

the edge margin is not less than 1.5D

Install Hi-Lok BACB30MB8A( )

or

BACB30MC8A( )

or

BACB30MD8A( )

or equivalent.

(a)

(b)

(c)

2

2

2

Use the same grip length as the

fastener that was removed in Step 4.

(a) Standard size.

(b) 1/64 oversize.

(c) 1/32 oversize.

FIGURE 1. INSPECTION

Jun 30/94 SHEET 3 OF 3 737-53A1166

REV 1: May 25/95 31
BOEING SERVICE BULLETIN 737-53A1166

S-19

S-18A

S-20

S-17

STA

716

STA

709

727A (737-200)

STA

747 (737-100)

STA

727

S-18

LEFT SIDE SHOWN

RIGHT SIDE OPPOSITE

(WING-TO-BODY FAIRING NOT SHOWN)

A

A

D23274

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION

Jun 30/94 SHEET 1 OF 3 737-53A1166

REV 1: May 25/95 32
BOEING SERVICE BULLETIN 737-53A1166

5

2

3

1

6

7

7

4

VIEW A-A

INBD

S-17

S-18

S-19

S-20

D23551

The step numbers shown below agree with the numbers shown inside the circle symbols in the figure.

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION

Jun 30/94 SHEET 2 OF 3 737-53A1166

REV 1: May 25/95 33
BOEING SERVICE BULLETIN 737-53A1166

STEP TASK NAME REFERENCES QTY NOTES

1 Remove /

Discard

Stiffener 1

2 Remove /

Keep

Tee Chord 1 Keep the tee chord to use

again.

3 Remove /

Discard

Web 1

4 Remove /

Discard

Angle 1

5 Remove /

Discard

Attach Angle 1

6 Remove /

Keep

Filler 1 Keep the filler to use again.

7 Remove /

Discard

Filler 2

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION

Jun 30/94 SHEET 3 OF 3 737-53A1166

REV 1: May 25/95 34
BOEING SERVICE BULLETIN 737-53A1166

1

DETAIL I

FLAP RIGHT ANGLE GEARBOX

RIGHT GEAR BOX SHOWN

LEFT GEARBOX SIMILAR

FWD

SEE DETAIL II

SEE DETAIL I

R07300

FIGURE 3. ACCESS FOR THE TIME LIMITED REPAIR

Jun 30/94 SHEET 1 OF 4 737-53A1166

REV 1: May 25/95 35
BOEING SERVICE BULLETIN 737-53A1166

SEE DETAIL III 5

2

3

S-20

4 SEE DETAIL III

S-19

S-18A

WL 190

INBD

RIGHT SIDE SIMILAR

LEFT SIDE SHOWN

DETAIL II

R07463

FIGURE 3. ACCESS FOR THE TIME LIMITED REPAIR

Jun 30/94 SHEET 2 OF 4 737-53A1166

REV 1: May 25/95 36
BOEING SERVICE BULLETIN 737-53A1166

FWD

INBD

727

STA

5

4

VIEW A-A

FWD

VIEW B-B

INBD

DETAIL III

B

B

S-18A

A A

5

S-19

S-18A

WL 190

4

4

5

R07478

FIGURE 3. ACCESS FOR THE TIME LIMITED REPAIR

Jun 30/94 SHEET 3 OF 4 737-53A1166

REV 1: May 25/95 37
BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

STEP TASK NAME PART NUMBER QTY NOTES

1 Remove/

Keep

Flap Right Angle

Gearbox

1 Keep the parts to use again.

Refer to AMM 27-51-261.

2 Remove/

Keep

Tee 65-48692-5 Left Side

65-48692-12 Right Side

1 Keep the tee to use again.

3 Remove/

Keep

Bracket 69-39436-2 Left Side

69-39437-2 Right Side

Keep the bracket to use again.

4 Trim

Apply

Apply

Shear Beam Web

Chemical Film

Treatment

(Alodine)

Primer

65-46877-( )

BMS 10-11, Type 1

1 Trim the aft part of the outboard

vertical side of the Shear Beam

Web to allow for the installation

of the Repair Angle.

Apply to cut area. Refer to 737

Structural Repair Manual

51-10-2

Apply one layer to cut area.

5 Trim

Apply

Apply

Horizontal

Stiffener

Chemical Film

Treatment

(Alodine)

Primer

65-46547-( )

BMS 10-11, Type 1

1 Trim the outboard part of the

vertical side of the Horizontal

Stiffener to allow for the

installation of the Repair Angle.

Apply to cut area. Refer to 737

Structural Repair Manual

51-10-2

Apply one layer to cut area.

FIGURE 3. ACCESS FOR THE TIME LIMITED REPAIR

Jun 30/94 SHEET 4 OF 4 737-53A1166

REV 1: May 25/95 38
BOEING SERVICE BULLETIN 737-53A1166

VIEW A-A

A

A

1 1

R07508

FIGURE 4. MAKE THE TIME LIMITED REPAIR PARTS

Jun 30/94 SHEET 1 OF 3 737-53A1166

REV 1: May 25/95 39
BOEING SERVICE BULLETIN 737-53A1166

7

8

6

3

4

2

5

6

R07515

FIGURE 4. MAKE THE TIME LIMITED REPAIR PARTS

Jun 30/94 SHEET 2 OF 3 737-53A1166

REV 1: May 25/95 40
BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

NOTE: Make the repair parts shown in the table that follows. Trim the repair parts to match the existing

equivalent airplane parts. Make sure that the fastener hole edge margin is not less than the

equivalent airplane part.

STEP TASK NAME MATERIAL QTY NOTES

1 Make

Heat Treat

Repair Angle

Repair Angle

AND10134-2008 x 20.8

7075-T0,

or equivalent.

Heat Treat to T-6

1

2 Make Shim 1.25 x 4.25 x 0.032 inch thick

7075-T6 Aluminum Alloy Sheet.

1

3 Make Repair Strap 1.25 x 6 x 0.18 inch thick

7075-T6 Aluminum Alloy Sheet.

1

4 Make Filler 1.4 x 8.2 x 0.18 inch thick

7075-T6 Aluminum Alloy Sheet.

1

5 Make Filler 1.2 x 1.4 x 0.15 inch thick

7075-T6 Aluminum Alloy Sheet

1

6 Make

Bend

Heat Treat

Repair Angle

Vertical Wall

Repair Angle

4 x 8.2 x 0.15 inch thick

7075-T0 Aluminum Alloy Sheet.

Heat treat to T-6.

1 Refer to 737 Structural

Repair Manual 51-20-1.

Use a minimum bend radius

of 0.44. Chamfer the aft

vertical edge 0.10 x 45

degrees to match the

Repair Angle made in Step

1.

Also, bend the vertical wall

so it will align with the filler

made in Step 4 and the

Repair Angle made in Step

1.

7 Make Shim 2.1 x 11.4 x 0.18 inch thick

7075-T6 Aluminum Alloy Sheet.

1

8 Make Shim 1.2 x 8.7 x 0.18 inch thick

7075-T6 Aluminum Alloy Sheet.

1

FIGURE 4. MAKE THE TIME LIMITED REPAIR PARTS

Jun 30/94 SHEET 3 OF 3 737-53A1166

REV 1: May 25/95 41
BOEING SERVICE BULLETIN 737-53A1166

SEE DETAIL I

SEE DETAIL II

DETAIL I

FLAP RIGHT ANGLE GEARBOX

RIGHT GEAR BOX SHOWN

LEFT GEARBOX SIMILAR

12

FWD

R07523

FIGURE 5. INSTALL THE TIME LIMITED REPAIR

Jun 30/94 SHEET 1 OF 5 737-53A1166

REV 1: May 25/95 42
BOEING SERVICE BULLETIN 737-53A1166

1 3

10 11

1 9

1 8

1

1 2

WL 190

S-18A

S-19

S-20

4 1 7

INBD

RIGHT SIDE SIMILAR

LEFT SIDE SHOWN

DETAIL II

B

B

A A

R07532

FIGURE 5. INSTALL THE TIME LIMITED REPAIR

Jun 30/94 SHEET 2 OF 5 737-53A1166

REV 1: May 25/95 43
BOEING SERVICE BULLETIN 737-53A1166

1 4

FWD

INBD

VIEW A-A

1 3

STA

727

1 7

1 5

1 2

1 6

R07567

FIGURE 5. INSTALL THE TIME LIMITED REPAIR

Jun 30/94 SHEET 3 OF 5 737-53A1166

REV 1: May 25/95 44
BOEING SERVICE BULLETIN 737-53A1166

1 5

1 7

1 6

VIEW B-B

LOOKING OUTBOARD

FWD

S-20

STA

727

S-18

S-18A

S-19

1 2

R07646

FIGURE 5. INSTALL THE TIME LIMITED REPAIR

Jun 30/94 SHEET 4 OF 5 737-53A1166

REV 1: May 25/95 45
BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

STEP TASK NAME PART NUMBER QTY NOTES

1 Install

Drill

Remove

Deburr

Apply

Apply

Repair parts

Fastener holes

Repair parts

Fastener holes

Chemical film

treatment (Alodine)

Primer BMS 10-11, Type 1

Temporarily install repair parts.

Remove sharp edges.

Refer to 737 Structural Repair

Manual 51-10-2.

2 Install Repair Angle (a) (refer to Figure 4, Step 1) 1 Install parts with BMS 5-95 fay

surface sealant. Refer to 737

Structural Repair Manual

51-20-4.

Install with BACB30 MB

fasteners the same size as

was removed. If necessary,

use oversize fasteners.

For new fastener locations, use

BACB30MB8-( ) fasteners.

Install fasteners wet with BMS

5-95 sealant.

3 Install Shim (b) (refer to Figure 4, Step 2) 1

4 Install Repair Strap (b) (refer to Figure 4, Step 3) 1

5 Install Filler (refer to Figure 4, Step 4) 1

6 Install Filler (refer to Figure 4, Step 5)

7 Install Repair Angle (refer to Figure 4, Step 6) 1

8 Install Shim (refer to Figure 4, Step 7) 1

9 Install Shim (refer to Figure 4, Step 8) 1

10 Install Bracket 69-39436-2 Left Side

69-39436-2 Right Side

1 Install the bracket removed in

Step 3 of Figure 3.

11 Install Tee 65-48692-5 Left Side

65-48692-12 Right Side

1 Install the tee removed in Step

2 of Figure 3.

12 Install Flap Right Angle

Gearbox

1 Install the Flap Right Angle

Gearbox removed in Step 1 of

Figure 3.

Refer to AMM 27-51-261.

(a) If necessary, the inboard edge of the repair angle can be trimmed to remove interference with

fasteners through the Repair Strap, (Step 4), Shim (Step 3), and Tee, (Step 11).

(b) The fastener at the inboard edge of the Repair Strap and Shim, as shown in the initial installation, can

be difficult to install. Trim the Repair Strap and Shim so that installation does not require removal of

this fastener. Detail II has been revised to show the changed installation.

FIGURE 5. INSTALL THE TIME LIMITED REPAIR

Jun 30/94 SHEET 5 OF 5 737-53A1166

REV 1: May 25/95 46
BOEING SERVICE BULLETIN 737-53A1166

LEFT SIDE SHOWN, RIGHT SIDE OPPOSITE

2.00R-2.50R

3 4

0.90

C,D C,D

3

4.20 1.20

0.14

.62R VIEW C-C 9`

2

0.25 0.25

9.25 0.10

VIEW B-B

0.10

0.21 FORM AFTER

MACHINING

.50R 2 LOCATIONS

4

1.20 3.70

0.14

.62R

VIEW D-D

9`

1

0.05 FORM AFTER

MACHINING

0.10

2.00R-2.50R

0.25 0.25

9.25 0.10

VIEW A-A

1 2 0.46

2.96

3.00

4.94

7.50 1.25

2.50

.62R

A,B A,B

14.35

R37837

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS

Jun 30/94 SHEET 1 OF 5 737-53A1166

REV 1: May 25/95 47
BOEING SERVICE BULLETIN 737-53A1166

11.42

6

2.68

2.34

2.46

16.66

7

15.86

.62R

.50R

2.62

8

.62R

2.34

1.25

1.25

19.06

9

.50R

2.62

2.34

1.25

R37960

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS

Jun 30/94 SHEET 2 OF 5 737-53A1166

REV 1: May 25/95 48
11.29

8.51

7.01

6.15

4.64

0.13

2.84

2.86

4.34

4.36

11.20

3.25

1.58

3.09

2.77

0.23

3.05

TYPICA

0.94

-1 SHOWN,-2 OPPOSITE

SEE DETAIL I

HOLE LAYOUT

4 LOCATIONS

0.28R

R37979

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS

REV 1: May 25/95

Jun 30/94 SHEET 3 OF 5 737-53A1166

49
BOEING SERVICE BULLETIN 737-53A1166

5

7.62

6.63

4.30

3.32

TYPICAL

0.38 TYPICAL 0.38

0.25 IN. 1.50

JOG UP OML

BEND 90`X.12R

-1 SHOWN,-2 OPPOSITE

HOLE LAYOUT

DETAIL I

R38342

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS

Jun 30/94 SHEET 4 OF 5 737-53A1166

REV 1: May 25/95 50
BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

STEP TASK NAME MATERIAL QTY NOTES

1 Make Strap

65C37566-5, Left

65C37566-6, Right

3.1 x 14.4 x 0.25 inch thick

7075-T6 Bare Plate

1 For Group 2 airplanes.

See View A-A

2 Make Strap

65C37566-7, Left

65C37566-8, Right

3.1 x 14.4 x 0.25 inch thick

7075-T6 Bare Plate

1 For Group 3 airplanes.

See View B-B

3 Make Filler

65C37566-9

1.0 x 5.5 x 0.14 inch thick

2024-T3 Bare Sheet

1 See View C-C

4 Make Filler

65C37566-10

1.0 x 5.0 x 0.14 inch thick

2024-T3 Bare Sheet

1 See View D-D

5 Make

Heat Treat

Splice Angle

69-87822-1, Left

69-87822-2, Right

Splice Angle

3.3 x 11.4 x 0.063 inch thick

2024-0 Clad Sheet

Heat Treat to T42

1 -

6 Make Strap

65C37566-4

2.8 x 11.5 x 0.10 inch thick

7075-T6 Clad Sheet

1 -

7 Make Strap

65C37566-3

2.5 x 16.7 x 0.10 inch thick

7075-T6 Clad Sheet

1 -

8 Make Strap

65C37566-2

2.7 x 16.0 x 0.10 inch thick

7075-T6 Clad Sheet

1 -

9 Make Strap

65C37566-1

2.7 x 19.2 x 0.10 inch thick

7075-T6 Clad Sheet

1 -

FIGURE 6. MAKE STRINGER 18A REPAIR PARTS

Jun 30/94 SHEET 5 OF 5 737-53A1166

REV 1: May 25/95 51

BOEING SERVICE BULLETIN 737-53A1166

ADDENDUM

FLIGHT SAFETY SECTION

INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME

A structural reassessment of the 737 airplane has been conducted under the 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.

Table I provides a summary of the inspections specified in Accomplishment Instructions, Part I - Flight Safety

Inspection Program and the Compliance Section, 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 outboard chord of the frame at BS 727.

Any cracked structure should be replaced prior to further flight unless specifically approved by your cognizant

regulatory agency.

Please report any discrepancies to Boeing Customer Support Engineering using the reporting system

described in the addendum.

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 1 of 6
BOEING SERVICE BULLETIN 737-53A1166

TABLE I - CHORD INSPECTION

Inspection

(See 737 Non

Destructive Test

Manual)

Airplane Condition Inspection Threshold

(Flight Cycles)

Repeat Inspection

Interval (Flight Cycles)

until Preventive

Modification is installed

Close visual inspection

of the the outboard

chord of the frame at

BS 727. Examine the

edge of the forward

flange.

Pulse Echo Shear

Wave inspection of the

outboard chord of the

frame at BS 727.

Examine area where

Stringer 18A is

attached.

High Frequency Eddy

Current inspection of

the outboard chord of

the frame at BS 727.

Examine two fastener

holes (i) (j).

High Frequency Eddy

Current inspection of

the outboard surface

of Stringer 18-A.

Examine around the

heads of two fastener

holes.

Service Bulletin

Modification not

accomplished.

Service Bulletin

737-53-1088 frame

replacement not

accomplished.

or

Service Bulletin

Modification not

accomplished.

Lower part of frame

replaced per Service

Bulletin 737-53-1088.

27,000 to 50,000 (a) 15,000 (e)

50,000 to 60,000 (b) 7,500 (f)

60,000 to 70,000 (c) 5,000 (g)

70,000 (d) 3,000

Service Bulletin

Modification not

accomplished.

Upper part of frame

replaced per Service

Bulletin 737-53-1088.

30,000 (after the

chord was replaced).

Use the intervals shown

above for flight cycles

after the chord was

replaced.

Close visual inspection

of the the outboard

chord of the frame at

BS 727. Examine the

edge of the forward

flange. (h)

Service Bulletin

Modification

accomplished.

Next scheduled

structural inspection.

Refer to the 737

Maintenance Planning

Data Manual

D6-17594-2, Section

6-02.

Use your Maintenance

Program Interval for

scheduled structural

inspections.

Refer to the 737

Maintenance Planning

Data Manual

D6-17594-2, Section

6-02.

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 2 of 6
BOEING SERVICE BULLETIN 737-53A1166

(a) For airplanes at this threshold, do the inspection initially within 4,500 flights after you get this bulletin.

(b) For airplanes at this threshold, do the inspection initially within 2,500 flights after you get this bulletin.

(c) For airplanes at this threshold, do the inspection initially within 1,500 flights after you get this bulletin.

(d) For airplanes at or over this threshold, do the inspection initially within 500 flights after you get this

bulletin.

(e) Use these intervals until the airplane collects more than 50,000 flights.

(f) Use these intervals until the airplane collects more than 60,000 flights.

(g) Use these intervals until the airplane collects more than 70,000 flights.

(h) Fully extend the trailing edge flaps. Get access to the outboard side of the frame at BS 727 through the

opening in the flap fairing. Get access to the inboard side of the frame at BS 727 from inside the

wheelwell.

(i) Airplanes with 60,000 to 70,000 cycles can omit this step only at the initial inspection at 1500 flights after

you get this bulletin.

(j) Airplanes with more than 70,000 cycles can omit this step only at the initial inspection at 500 flights after

you get this bulletin.

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 3 of 6
BOEING SERVICE BULLETIN 737-53A1166

Boeing requests that operators use the following Structural Significant Item (SSI) Reporting System to report

any discrepancies that are found in accomplishing a Flight Safety Inspection.

1. Upon recognition of discrepancy, the following information should be telegraphed to Boeing:

Heading: ATTENTION - SSI DISCREPANCY - SERVICE BULLETIN RELATED

- Service Bulletin number

- Airplane serial number on which discrepancy was found

- Identification of structural item found damaged

- Flight cycles and hours on damaged item

- Location and description of damage including direction and size

- When discovered and inspection method used

Send telegram through Boeing Field Service Representative or directly to:

737 Customer Support Engineering

2. An Operator's Follow-Up Report containing all available pertinent data, relative to the structural

discrepancy, shall be sent to Boeing. A summary of the information that 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 or directly to:

The Boeing Commercial Airplane Group

P.O. Box 3707

Seattle, Washington 98124-2207, USA

Attn: 707/727/737 Service Engineering Director

Org. M-7201 Mail Stop 2H-84

4. All reports will be reviewed promptly.

5. The Boeing Company will summarize the results of all reported significant data for distribution

semi-annually to operators and appropriate Airworthiness Authorities.

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 4 of 6
BOEING SERVICE BULLETIN 737-53A1166

DISCREPANT STRUCTURE REPORT SIDE 1

1 REPORT DATA A.T.A. INDEX REPORT NO. __

AIRLINE/AGENCY __________________ STATION MONTH DAY YEAR________

2 AIRCRAFT DATA MODEL ___________________ SERIES _____________ TAIL NO. ___________________________________

MFG. SERIAL NO. ____________________________ FLIGHT HOURS _________________ FLIGHT CYCLES _________________________

3 COMPONENT DATA (AS APPLICABLE AND AVAILABLE):

NAME ________________________________________________ P/N _________________________ S/N ____________________________

IPC/DWG. REF. ________________________________________ SRM REF. ____________________________________________________

COMPLETE THE FOLLOWING IF KNOWN AND DIFFERENT FROM SECTION 2:

COMPONENT FLIGHT HOURS SINCE NEW ____________________________ SINCE OVERHAUL ____________________________

COMPONENT FLIGHT HOURS SINCE NEW ____________________________ SINCE OVERHAUL ____________________________

4 REPAIR DATA [] PLANNED [] COMPLETED

4A ACTION ___________________________________________________________________________________

___________________________________________________________________________________________

___________________________________________________________________________________________

4B REFERENCE ASSOCIATED WITH INSPECTION/REPAIR (SPECIFY NO., PAGE, FIGURE, ETC):

SB_______________________ AD _______________________ IPC ________________________ SRM ______________________________

MPD_____________________ OTHER (E.G. SDR, MRR) __________________________________ SIIA ______________________________

STRUCTURAL SIGNIFICANT ITEM NO. _________________ SERIES 50 NO. __________________________

5 SERVICE BULLETINS INCORPORATED IN AREA OF DISCREPANCY

SERVICE BULLETIN APPLICABLE SECTION DATE OF TOTAL FLIGHT HOURS AND

NO. OF SERVICE BULLETIN INCORPORATION CYCLES AT INCORPORATION

_________________ ____________________ ________________ __________ HOURS ________ FLIGHTS

_________________ ____________________ ________________ __________ HOURS ________ FLIGHTS

_________________ ____________________ ________________ __________ HOURS ________ FLIGHTS

6 INSPECTION DATA (COMPLETE KNOWN INFO., CHECK APPROPRIATE ITEMS FOR DISCREPANT STRUCTURE):

CURRENT INSPECTION INTERVALS (FLIGHTS) _________________ _________________ ________________ ________________

CORRESPONDING INSPECTION LEVELS _________________ _________________ ________________ ________________

6A WHEN DISCOVERED 6B INSPECTION LEVEL 6C DETECTION METHOD

[] SCHEDULED MAINTENANCE

[] OVERHAUL

[] UNSCHEDULED

[] SPECIAL/DIRECTED (AD, SB...)

[] SYMPTOM (FUEL/PRESS LEAK...)

[] RELATED FLEET EXPERIENCE

[] ACCIDENT INVESTIGATION

[] SSID

[] SERIES 50

[] ______________________

[] WALK - AROUND

[] GENERAL VISUALL

[] EXTERNAL SURVEILLANCE

[] INTERNAL SURVEILLANCE

[] DETAILED

[] SPECIAL

[]

______________________

[] VISUAL

[] MAG. VISUAL

[] DYE PENETRANT

[] ULTRASONIC

[] LOW

FREQUENCY

EDDY CURRENT

[] HIGH

FREQUENCY

EDDY CURRENT

[] BORESCOPE

[] MAGNETIC

PARTICLE

[] TAP TEST

[] SOUND

[] SMELL

[] FEEL

[] X-RAY

[] PRESS. LOSS

[] __________

[] __________

[] __________

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 5 of 6
BOEING SERVICE BULLETIN 737-53A1166

DISCREPANT STRUCTURE REPORT SIDE 2

7 DISCREPANCY DESCRIPTION: ______________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

Attach sketch, photos and text as required to describe defect and specific location. When applicable give details of associated

discrepancies on the same aircraft, related experience with this discrepancy on any aircraft, and previous modification (s) to the

discrepant structure.

7A TYPE OF DISCREPANCY:

[] BENT

[] BROKEN

[] BUCKLED

[] BURNED

[] CLOGGED

[] CONTAMINATED

[] CORRODED

[] CRACKED

[] DEFORMED

[] DELAMINATED

[] DENTED

[] DETACHED

[] IMPROPERLY

ADJUSTED

[] LEAK

[] LOOSE

[] MISSING

[] OUT-OF-TOLERANCE

[] STUCK

[] WORN

[] WRINKLED

[]_________________

[]_________________

[]_________________

[]_________________

7B SIZE OF DISCREPANCY: [] INCHES, OR [] CENTIMETERS

AREA__________________________ X ____________________________ DEPTH ________________________________________________

CRACK LENGTH INITIALLY DETECTED ________________________________________ DATE ____________________________________

FINAL MEASUREMENT (IF DIFFERENT) ________________________________________ DATE ____________________________________

7C DISCREPANT PART:

[] FRAME/BULKHEAD

[] PRESSURE BULKHEAD

[] FRAME AROUND OPENING

[] WINDOW FORGING

[] KEEL BEAM

[] FLOOR

[] WING CENTER SECTION

[] WING DRY-BAY AREA/COMPT.

[] SPAR

[] RIB

[] LANDING GEAR BEAM

[] FLAP TRACK

[] FAIRING

[] _______________________________________

[] SKIN

[] PLATE/PANEL

[] CHORD

[] STRINGER NO.

[] BEAM

[] STRUT/BRACE

[] LINK/ROD

[] LONGERON

[] FITTING

[] BRACKET/CLIP

[] STOP

[] FASTENER

[] ________________________________

[] ________________________________

[] JOINT/SPLICE

[] LUG

[] WELD

[] BOND

[] OPEN HOLE

[] FASTENER HOLE

[] CUT-OUT

[] ACCESS/LIGHTENING HOLE

[] NOTCH/GROOVE

[] DISCONTINUITY

[] BASIC MATERIAL

[] BUSHING

[] PIN

[] ____________________________

7D LOCATION OF DISCREPANT PART:

GENERAL LOCATION (E.G., BILGE, UNDER GALLEY) ______________________________________________________________________

[] BODY STA. NO. __________

[] WING STA. NO. ___________

[] VERT. STAB. STA. ________

[] HORIZ.STAB.STA. ________

[] NACELLE/PYLON

COMPARTMENT _________

[] NOSE LANDING GEAR

[] MAIN LANDING GEAR

[] WING LANDING GEAR

[] BODY LANDING GEAR

[] DOOR/ACCESS PANEL

[] RUDDER

[] ELEVATOR

[] AILERON

[] FLAP

[] SLAT

[] SPOILER

[] TAB (ALSO CHECK ABOVE)

[] ________________________

[] ________________________

[] INTERIOR

[] INBOARD

[] LEFT

[] FORWARD

[] UPPER

[] LEADING EDGE

[] MIDDLE

[] EXTERIOR

[] OUTBOARD

[] RIGHT

[] AFT

[] LOWER

[] TRAILING EDGE

[] SIDE

[] SPECIFIC LOCATION __________________________________

________________________________________________________

________________________________________________________

INSPECTED BY REPAIRED BY

ORIGINATED BY DATE

Jun 30/94 ADDENDUM

REV 1: May 25/95 Page 6 of 6
Commercial

Airplane

Group

737

Service Bulletin

Number: 737-53A1166 Evaluation Form

Date: June 30, 1994

Revision 1: May 25, 1995

ATA System: 5311

Prepared By: Steve Lemon

SUBJECT: FUSELAGE - FRAMES - BODY STATION 727 OUTBOARD CHORD AT STRINGER 18A,

INSPECTION AND PREVENTIVE MODIFICATION

Use this evaluation form to tell us what you think of the quality of this service bulletin. We will use the data

that you give us to improve the quality of our service bulletins. Please include data about these or other

items:

- Did this service bulletin meet your estimate of quality?

- How easy is this service bulletin to understand?

- Are the Planning Information, Material Information and Accomplishment Instructions satisfactory?

- Will you do this service bulletin fully? If not, please tell us why.

- Is the Manpower estimate satisfactory?

NOTE: Please do not use this evaluation form to tell us to make changes to your manuals. To make these

changes, please use a Publication Change Request (PCR) form.

Please give us this data:

OPERATOR: TODAY'S DATE:

PREPARED BY: TITLE:

ORGANIZATION: TELEX CODE:

TELEPHONE NUMBER:

COMMENTS:

If you have other comments please use the other side. Thank you for the time you used to complete this

form.

Give the completed evaluation form to your Boeing Field Service Representative or send the evaluation form

directly to this address:

T. J. Taylor, Manager

Service Bulletin Engineering

Boeing Commercial Airplane Group

P.O. Box 3707, Mail Stop 20-85

Seattle, WA 98124-2207

BOEING COMMERCIAL AIRPLANE GROUP P.O. BOX 3707 SEATTLE, WASHINGTON 98124-2207 Page 1 of 1