# Boeing Alert Service Bulletin 737-53A1166: U.S. DOT/FAA - Service Information - SB-737-53A1166-00

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2011-0722; AD 2012-23-04 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 737-53A1166](https://openairdocs.org/service-documents/boeing/737-53a1166.md)
- Title as filed: U.S. DOT/FAA - Service Information - SB-737-53A1166-00
- Pages: 52
- PDF: https://openairdocs.org/files/sha256/d1/de/d1dea4c2552acbb06ac0b86f24dc634a31be2584c2268606c21af1526928aabf
- Page: https://openairdocs.org/service-documents/boeing/737-53a1166/file/d1dea4c2552a

## Text

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### Page 1 (OCR)

BALIND  Airplane  Commercial  737
Group  Service Bulletin
-ALERT:
Number:  737-53A1166
Date:  June 30, 1994  Summary
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.
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
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 airpiane 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
instructions from Boeing.  the outboard chord of Stringer 18A, get repair
If cracks are found in the outboard chord of the
frame at BS 727, install the time limited repair or
replace the chord ano,  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 (SB) 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
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.
BOEING COMMERCIAL AIRPLANE GROUP P.O. BOX 3707 SEATTLE, WASHINGTON 98124-2207
Summary Page 1 of 2

### Page 2 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
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.
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.
EXAMINE AREA AROUND
STRINGER 18-A  TWO FASTENER HOLES
CON SOME AIRPLANES  STA
THE OUTER CHORD OF  727
STRINGER 18-A IS
A FLAT STRAP)
TYPICAL
CRACK
EXAMINE FORWARD
EDGE OF FLANGE
EXAMINE SURFACE OF S-18A
AROUND TWO FASTENER HEADS
LEFT SIDE SHOWN
RIGHT SIDE OPPOSITE
(WING-TO-BODY FAIRING NOT SHOWN)
Summary Page 2 of 2

### Page 3 (OCR)

BOLING  Commercial
Airplane  737
Group  Service Bulletin
—ALERT:
Number:  737-53A1166
Date:  June 30, 1994
ATA System: 5311
SUBJECT: FUSELAGE - FRAMES - BODY STATION 727 OUTBOARD CHORD AT STRINGER 18A,  INSPECTION AND PREVENTIVE MODIFICATION
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.  THIS SERVICE BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN
1. PLANNING INFORMATION
A. Effectivity
1. Airplanes
Number, and Serial Number data.  Refer to Service Bulletin Index Document D6-19567, Part 3 for Airplane Variable Number, Line
This service bulletin is for the airplanes shown below.
IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER
AER LINGUS (ARL)
2 PG255  PG573  PY322
3 РК029  PK641-PK642 PY281
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
AERON AVIATION (AAV)
2 PJ072
AIR ALGERIE (ALG)
З РК361  PK631  PK633-PK634 PL717-PL725 PY051-PY053
Jun 30/94
737-53A1166
Page 1 of 44

### Page 4 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
AIR ATLANTA ICELANDIC (AID)
2 PY002
AIR FRANCE (AFA)
3 PL502-PL503 PN101-PN112
AIR GABON S.A. (GBN)
3 PY191
AIR GUINEE (GNE)
3 РУ651
AIR MADAGASCAR (MAD)
2 PG375
3 PL793
AIR MALTA (MLT)
3 PL621-PL623
AIR NAURU (NAU)
3 РК356  PK581  PY286
AIR NEW ZEALAND, LTD. (ANZ)
3 PJ009  PJ117-PJ119 PK214 _PY741
AIR ONE AB SWEDEN (AOW)
3 PJ003
AIR SOUTH, INC. (SOT)
3 PK462  PK466
AIR TANZANIA (TNZ)
3 PY611-PY612
AIR TOULOUSE INTERNATIONAL (TOL)
2 PL716
AIR ZAIRE (ZAI)
3 PY111  PY113
ALASKA AIRLINES (ASA)
З РУ112  PY134-PY135 PY270  PY461-PY462
ALBATROS AIRLINES (ABS)
2 PG251  PG253
ALL NIPPON AIRWAYS CO. LTD. (ANA)
2 PG584-PG586
3 РК711-PК716
ALOHA (ALO)
2 PG046
3 PK286-PK287 PК691-PK695 PK697 PY231 PY242 PY451
AMC AVIATION (AMF)
3 РК254
Jun 30/94  737-53A1166
2

### Page 5 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
AMERICA WEST AIRLINES, INC. (AMW)
2 PC004  PG036  PL801
3 PK283  PK696  PL081  PL172  PL551-PL562
AMIRI FLIGHT (ABD)
3 PK495
ANGOLA AIRLINES (ANG)
3 PK661  PK664  PY162
ANSETT WORLDWIDE AVIATION SERVICES (AWW)
1 PA001  PA003-PA004
2 PC003
ARAMCO ASSOCIATED CO. (ARM)
3 PL151  PY241  PY243-PY244
ARKIA ISRAELI AIRLINES, LTD (ARK)
2 PG575
ASEAN AVIATION (L) INC. (ASJ)
2 PG578-PG583
ATASCO USA, INC. (ATJ)
3 PL762
AVENSA (AVN)
3 PK042-PK043
AVIATECA (AVT)
2 PL737  PL740-PL741
3 PY201
AVIOGENEX AIR TRANSPORT (AVG)
3 PL501  PL506
BEST LEISURE (BES)
3 PJ108  PJ113
BHOJA AIR (BHO)
3 PK614
BOURAQ INDONESIA AIRLINES (PTB)
2 PJ001  PL742  PL803
3 PK501  PL743-PL744
BRAATHENS S.A.F.E. (BRT)
3 PK882
BRITISH AIRWAYS (BAB)
3 PK731-PK749 PK771-PK772 PK774-PK777 PK779  PN001
CALDWELL AIRCRAFT TRADING CO. (CAS)
2 PG402
CAMEROON AIRLINES (CAM)
2 PY046-PY047
Jun 30/94
737-53A1168

### Page 6 (OCR)

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
CARNIVAL AIR (CVL)
2 PG305  PG312  PL712
3 PJ007-PJ008
CASINO EXPRESS (CIN)
2 PG279  PG436
3 PK461
CAYMAN AIRWAYS (CAY)
3 PK222  PK561
CHINA SOUTHERN AIRLINES (GUN)
3 PK636-PK637
CIS AIR HOLDINGS, LTD. (CIS)
2 PG302
COMAIR (CML)
2 PG354  PG356
CONQUEST SUN AIRLINES, INC. (CQT)
2 PG438
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
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 PK632  PL221  PL611
4 PN131-PN135
E G AND G (EGN)
2 PG037  PG208  PG210  PG215  PG431
3 PL763
EAS EUROPE AIRLINES (EUR)
3 PK203  PK215  PK282  PK359  PK564  PK612
EAST WEST AIRLINES (INDIA) (BOM)
3 PK615-PK616 PK819  PK824  PL171
Jun 30/94  737-53A1166

### Page 7 (OCR)

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 РК241  PL758
FLIGHTSTAR AVIATION CORPORATION (FST)
2 PG274
FORTUNE AVIATION (FOR)
3 РК432
FRENCH POSTAL OFFICE (FPO)
2 PY302  PY344
З PY101-PY103
FRONTIER AIRLINES (FRO)
2 PG306  PG308
GATARI AIR SERVICE (GRI)
3 PL441
GB AIRWAYS (GBA)
3 PJ110-PJ111
GOVERNMENT OF BRAZIL (BRZ)
3 PК068-PK069
GOVERNMENT OF MEXICO (MXG)
2 PC005  PG223
GOVERNMENT OF SHARJAH (SHJ)
3 PL581
GPA GROUP LTD. (GUI)
З РК252  PК354-PK355
GULF AIR (GUL)
3 PК464  PK467-PK468
HAPAG LLOYD (HAP)
3 PL504
Jun 30/94
137-53A1166

### Page 8 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
HEAVYLIFT AIRCRAFT ENGINEERING (HVL)
3 PJ109
INDIAN AIR FORCE (IDF)
2 PH712-PH713
4 PM016-PM017
INDIAN AIRLINES (IND)
2 PH70S  PH711
3 PH021  PH024  PК231-PК233 PК235-PК240 PM001-PМ006 PY631
INDONESIAN AIR FORCE (IDO)
3 PL601-PL602
4 PL603
INTEGRATED RESOURCES (INH)
1 PG271
2 PG273  PG403
INTERAMERICA S.A. DE C.V. (INJ)
2 PL761
INTERNATIONAL AIR LEASES (IAL)
2 PG043  PG047-PG048
INTERNATIONAL AIRLINE SUPPORT GROUP (ASG)
2 PG021
"2 PG22TIONAL PACIT2 TRADINGS 4 (PT)  2 PG224  PG572  PJ102
TRAN AIR (IRN)
2 PH731  PY021
З РК391  PY022
IRAQI AIRWAYS (IRQ)
3 PY141-PY142
JAPAN TRANSOCEAN AIR CO., LTD. (SWL)
3 PK521  PiC523-PK525
JETALL HOLDING CORPORATION (JEL)
2 PY005
KENYA AIRWAYS (KEN)
З РК253  PK256
LACSA (LAC)
З РК357  PK871
LADECO (LDE)
2 PL802
3 PJ004-PJ006 PK212  PK281  PK826  PK830
LAN-CHILE S.A. (LAN)
3 РК360  PK825  PLO25  PL028
Jun 30/94  737-53A1166
6

### Page 9 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
LAPA (LAZ)
2 PG355
3 РК047  PK051  PK463
LINA CONGO (LNA)
3 PY411
LINHAS AEREAS DE MOCAMBIQUE (LAM)
2 PH703  PY031
LITHUANIAN AIRLINES (LIJ)
3 PК563
LUFTHANSA GERMAN AIRLINES (DLH)
2 РY345-РY346
3 РК901-PК903 РК905  PK911-PK927 PK929-PK931
MALEV HUNGARIAN AIRLINES (HGA)
3 PК284-PK285 PK827
MANDALA AIRLINES (MND)
3 РК874  PLO27  PL061  PL421  PN002
MARKAIR, INC. (ALK)
4 PY056-PY057
MIDAIR (MAI)
2 PY342
MODILUFT (MOU)
3 PК908-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 PL784-PL788
NORDAM (NOP)
3 РК221
NORDIC EAST (NOE)
2 PJ002
NWT AIR (NTA)
2 PX701
З РУ132-PY133
Jun 30/94
737-53A1166

### Page 10 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
OLYMPIC AIRWAYS (OLY)
3 РК301-РК304 РК307-PК310 PМ021-PМ023
P.T. AIRFAST (PTF)
2 PG204  PG278  PY343
PETROLAIR SYSTEMS S.A. (PTS)
3 PL471
PLUNA (PLU)
3 PL201-PL203
POLARIS AIRCRAFT LEASING CORP. (PLS)
1 PG272
2 PG202  PG205  PG207  PG218-PG219 PG276  PG651-PG652
3 PК026-PК028
PRESIDENTIAL AIR (PRB)
2 PG432
REPUBLIC OF NIGER (NIR)
3 PY166
ROYAL AIR MAROC (RAM)
3 PK271-PK274 PY671
4 PY672
RYANAIR (RYR)
3 PJ114-PJ115 PK801-PK804
SABENA S.A. (SAB)
3 РК041  PК044-PК046 PК048-PK050 PK052-PK053 PК431 PК433
PY272-PY275
SAETA S.A. (SAE)
3 PK211  PK213
SAHARA INDIAN AIRLINES (SAQ)
3 PK820
SAHSA (SERVICIO AEREO DE HONDURAS,S.A.) (SAH)
2 PJ032  PJ071  PL736
SAUDI ARABIAN AIRLINES CORP. (SVA)
2 PL726-PL728 PY036-PY037
3 PK311-PK317 PL729-PL735
SAUDI ROYAL FLIGHT (SRF)
З РК318
SERVICIOS AEREOS RUTAS ORIENTE, (SARO) (SEV)
2 PA015  PA021-PA022
3 РК351  PK353
SHAHEEN AIR INTERNATIONAL (SHK)
3 РК514
Jun 30/94
737-53A1166

### Page 11 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
SHANNONAIR LEASING LTD. (SLE)
3 РК352
SIERRA PACIFIC AIRLINES (SP)
3 PК627
SOUTH AFRICAN AIRWAYS (SAA)
2 PG353
3 PL101-PL113
SOUTHWEST AIRLINES CO. (SWA)
З РК082  PК091-PK099 PK541-PK560 PК621  PK628-PK630 PM051-PM062
SUDAN (SUD)
3 PY156-PY157
T A PORTUGUESES (TAP)
3 PК971  PK973-PK974 PN083
4 PN084-PN086
TACA INTERNATIONAL AIRLINES, INC. (TAC)
2 PG059  PG352
3 PK223  PY131
TAESA (TES)
3 PK622  PK625-PK626
TAT EUROPEAN AIRLINES (TTR) PY321  2 PY003  РY301  PY361-PY362
THAI AIR FORCE (TAF)
4 PK519
THAI AIRWAYS INTERNATIONAL, INC. (TII)
3 РК511
TRANSAERO (TRX)
3 PК451-PK452 PK773
TRANSAVIA AIRLINES (TAV)
2 PG074
3 РК502-PК504 PК821
TRANSMILE AIR SERVICES (TML)
2 PY323  PY381
TUNIS AIR (TUN)
3 PKК861-PК863 PY621
UNITED AIR LINES, INC. (UAL)
1 PG001-PG004 PG006-PG008
2 PG009-PG013 PG015-PG019 PG022-PG025 PG027  PG038-PG040 PG045  PG075  PG051-PG054 PG057  PG060-PG063 PG065-PG072  PG030  PG032-PG033
3 PK201-PK202 PL002-PL023
UNITED STATES AIR FORCE (USF)
3 PJ201-PJ219
Jun 30/94  737-53A1166
9

### Page 12 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
USAIR, INC. (USA)
2 PG041-PG042 PG073  PG206  PG301  PG303-PG304 PG307
PG309 PG311 PG313-PG314 PG474  PG576
3 PK288-PK289 PK591-PK599  PK601-PK610 PK883  PM101-PM117 PN021-PN028
4 PM118-PM119 PN029-PN038
USL CAPITAL (USL)
2 PY001
VARIG AIRLINES (VAR)
3 PK111-PK116 PK118-PK120 PK141-PK146 PL453-PL454
VARSA (VAB)
2 PG351
VASP (VSP)
2 PG435  3 PH011-PH013 PК061-PК062 РК065-PК067  PG437  PG439-PG440 PG471-PG473 PL756  PX071
VENEZUELA - GOVERNMENT OF (VNZ)
З РК070
VISCOUNT AIR SERVICE INC. (VAS)
2 PG201  PG203  PG209  PG212  PG216-PG217 PG220-PG222
PJ101  PJ103
3 РК305-РК306
WHIRLPOOL FINANCIAL CORP (ZZW)
2 PG214
XIAMEN AIRLINES CO. LTD. (XIA)
3 РК635
YEMEN AIRWAYS (YEM)
3 РК341
ZAMBIA AIRWAYS (ZAM)
3 PK291  PL026
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  PG701-PG705  PH701-PH715  PG501-PG505 PG571-PG586 PG621-PG630 PG651-PG652  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
РY341-РY346  PY361-PY362  PY381
Jun 30/94  737-53A1166
10

### Page 13 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
GROUP 3
PJ201-PJ219  PK101-PK103  PH001  PK231-PK241  PH011-PH013  PK026-PK029  PK251-PK258 PK271-PK274  PK111-PK120  PK041-PK053  PK141-PK146  PH021-PH024  • PH743  PK061-PK070  PK201-PK204  PK281-PK289  PK081-PK082  PK211-PK215  PJ003-PJ009  PK091-PK099  PK221-PK223  PJ105-PJ119  PK301-PK318
PL001-PL028  PK691-PK697  PL201-PL203  PK591-PK599  PK711-PK716  PK601-PK617  PК351-PK361  PK501-PK504  PK861-PK863  PK621-PK637  PK731-PK749  PK511-PK514  PK871-PK874  PL401-PL417  PK771-PK779  PK881-PK884  PK641-PK642  PL101-PL113  PK521-PK525  PK431-PK433  PK451-PK452  PK541-PK564  PK661-PK664  PK801-PK804  PK901-PK932  PK671-PK680  PK819-PK827  PK461-PK469  PK971-PK974  PL451-PL454  PL171-PL172
PL621-PL623  PL631-PL632  PL501-PL506  PL717-PL725  PL551-PL562  PL729-PL735  PL601-PL602  PL743-PL745
PN101-PN112  PY131-PY135  PM051-PM062 PM101-PM117 PM141-PM142 PN001-PN002  PY141-PY143  F L762-PL770  PL781-PL788  PY151-PY154  PY156-PY157  PY051-PY053  PY161-PY162  PM001-PM006 PM021-PM023  PN021-PN028  PY101-PY103  PN081-PN083  PY111-PY113
PY221-PY222 PY231  PY241-PY244 PY270-PY275
PY461-PY462 PY611-PY612 PY621  PY421-PY422 PY441
GROUP 4
PN131-PN135 PY056-PY057 PY672-PM017 PM118-PM119 PN029-PN038 PN084-PN086
2. Spares
None
Jun 30/94
737-53A1166
11

### Page 14 (OCR)

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.
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, get repair instructions from Boeing.
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.
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BOEING SERVICE BULLETIN 737-53A1166
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.  The repair is time limited. Within 4500 flight cycles, but not more than 18 months, after the repair was
If no cracks are found, install the preventive modification or do the inspection again.
installed.  Do the inspection at the times given in the Compliance section until the preventive modification is
necessary.  If the preventive modification is installed, no more inspections, per this service bulletin, are
More work is necessary for operators that have replaced the chord as shown in Service Bulletin (SB)  737-53-1088 (refer to Compliance section).
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 builetin.
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.
intervals shown above.  For airplanes with the lower part of the chord replaced by SB 737-53-1088, do the inspection at the
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.
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 and do
not apply to airplanes on which other configuration changes have been made.
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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 cure the materials
- Time to make the parts
- Time to find the tools.
Inspection only.
Task  Number of Persons  Man-Hours  Elapsed Time (Hours)
Open Access  1  1
Inspection  1.5  1.5
Close Access  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  З
TOTAL FOR REPAIR  42  21
Preventive Modification.
Task  Number of Persons  Man-Hours  Elapsed Time (Hours)
Open Access  2  32  16
Preventive  2  40  20
Modification
Close Access  2  27  13.5
TOTAL FOR MODIFICATION  99  49.5
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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.
ROLT  Unit Price thru
Kit Number  Name  (weeks)  Sep 16/94
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
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
Change in Weight  Change in Moment
Task  (Pounds)  (Pound-Inches)
+(-)  +(-)
Preventive Modification  +3.7  +2690
Repair  +6.5  +4755
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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
1. 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  DON  ADCN  Title
65C37277  PL  1  Strap Installation - Station 727 Bulkhead,
S-18 to S-20, Preventive Modification (Top Kit)
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.
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
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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.
NOTE: One top kit and operator supplied materials specified in Paragraph II.A.2., Parts and
Materials Supplied by the Operator, are necessary for each side of the airplane.
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)  Top Kit (Left Side)
65C37277-2 (a) (e)  Top Kit (Right Side)
65C37277-3 (b) (e)  Top Kit (Left Side)
65C37277-4 (b) (e)  Top 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)  Top Kit (Left Side)
65C37277-6 (c) (e)  Top Kit (Right Side)
65C37277-7 (d) (e)  Top Kit (Left Side)
65C37277-8 (d) (e)  Top 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 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,  Gloss Enamel
Color BAC702 White
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
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
4 × 8 x 0.15 inch thick 7075-T0  Aluminum Alloy Sheet
AND10134-2008 × 20.8, 7075-T6  Extruded Angle
or equivalent
1.25 x 4.25 x 0.032 inch thick 7075-T6  Aluminum Alloy Sheet
1.25 × 6 x 0.18 inch thick 7075-T6  Aluminum Alloy Sheet
1.4 × 8.2 x 0.18 inch thick 7075-T6  Aluminum Alloy Sheet
1  2.1 × 11.4 × 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 l.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 (refer to Figure 1). Look for
cracks in the surface around the heads of the two fasteners immediately aft of BS 727.
E. If there are cracks in the outboard chord of Stringer 18-A, get repair instructions from Boeing.
F. Examine the edge of the forward flange of the outboard chord of the frame at BS 727 (refer to Figure  1). Look for cracks.
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 to 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 Ill 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  1 ki per Service
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 Il 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 Il 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
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.
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BOEING SERVICE BULLETIN 737-53A1166
S. Send a report of the inspection to Boeing (refer to Paragraph C. Description and the Flight Safety  Section in the Addendum).
Part II Preventive Modification
A. Get access to the outboard side of the outboard chord at Body Station (BS) 727 between Stringers
747 (for 737 -100 airplanes) or 727A (for 737-200 airplanes). Refer to Figure 2.  S-17 and S-20. Also, get access to the outboard side of Stringers S-18A and S-19 from BS 709 to BS
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:  FASTENERS ARE REMOVED.  TO INSTALL THE PREVENTIVE MODIFICATION, SKIN PANEL ATTACHMENT  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.
VOTE: alien T5) 31 124. Anon,  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 127, 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.
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BOEING SERVICE BULLETIN 737-53A1166
Illustration Table of Contents
Title  Page
FIGURE 1. INSPECTION .  26
FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION  29
FIGURE 3. ACCESS FOR THE REPAIR  32
FIGURE 4. MAKE THE REPAIR PARTS  36
FIGURE 5. INSTALL THE REPAIR  39
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BOEING SERVICE BULLETIN 737-53A1166
SEE DETAIL I
LEFT SIDE SHOWN
RIGHT SIDE OPPOSITE
(WING-TO-BODY FAIRING NOT SHOWN)
FIGURE 1. INSPECTION
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BOEING SERVICE BULLETIN 737-53A1166
STRINGER 18-A  STA
727
CON SOME AIRPLANES
THE OUTER CHORD OF
STRINGER 18-A IS
A FLAT STRAP)
0000o  _ SEE DETAIL II
STA
727
INBO
DETAIL
STRINGER 18-A
TYPICAL
CRACK
3
DETAIL II
FIGURE 1. INSPECTION
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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  High Frequency  NDT Part 6, 51-00-00,  Examine the outboard
of Stringer 18-A  Eddy Current  Figure 4  surface of the outboard
Inspection  chord around the
fastener head. Look for
cracks.
2  Examine  Outboard chord  Close Visual  Examine the edge of the
of frame  Inspection  forward flange of the
outboard chord. Look for
cracks.
Examine  Outboard chord  Pulse Echo  NOT Part 4, 53-10-01  Examine the area under
of frame  Shear Wave  the outboard chord of
Inspection  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 /  Lockbolt  BACB30GW8()  2  Measure the grip length of the
Discard  Collar  BACC30K8  2  fastener that was removed.
STEP  TASK  NAME  PROCEDURE  REFERENCES  NOTES
5  Examine  Fastener Holes  High Frequency  NDT Part 6, 51-00-00,  Examine the fastener
Eddy Current  Figure 1  holes in the forward
Inspection  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  2  if necessary, drill oversize hole
hole  to remove damage. Make sure that
the edge margin is not less than 1.5D
Install  • Hi-Lok  BACB30MB8A() (a)  Use the same grip length as the
or  fastener that was removed in Step 4.
BACB30MC8A() (b)  2
or
BACB30MD8A() (c)
or equivalent.
(a)  Standard size.
(b)  1/64 oversize.
(c)  1/32 oversize.
FIGURE 1. INSPECTION
Jun 30/94  SHEET 3 OF 3  737-53A1166
28

### Page 31 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
STA
STA
STA  727
709
716
STA
747(737-100)
S-17  727A (737-200)
•0
• S-18
S-18A
00 00000000  10 0
S-19
/o
S-20
LEFT SIDE SHOWN
RIGHT SIDE OPPOSITE
(WING-TO-BODY FAIRING NOT SHOWN)
FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION
Jun 30/94  SHEET 1 OF 3  737-53A1166
29

### Page 32 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
- 5-97
- 5-18
-5-19
+ + + +  - 5-20
INBO
VIEW A-A
FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION
Jun 30/94  SHEET 2 OF 3  737-53A1166
30

### Page 33 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
The step numbers shown below agree with the numbers shown inside the circle symbols in the figure.
STEP  TASK  NAME  REFERENCES  QTY  NOTES
1  Remove /  Stiffener  1
Discard
2  Remove /  Tee Chord  1  Keep the tee chord to use
Keep  again.
Remove /  • Web  1
Discard
4  Remove /  Angle
Discard
5  Remove /  Attach Angle
Discard
6  Remove /  Filler  1  ¡Keep the filler to use again.
Keep
7  Remove /  Filler  2
Discard
FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION
Jun 30/94  SHEET 3 OF 3  737-53A1166
31

### Page 34 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
SEE DETAIL II
SEE DETAIL I
FHD.
DETAIL I
FLAP RIGHT ANGLE GEARBOX
RIGHT GEAR BOX SHOWN
LEFT GEARBOX SIMILAR
107300
FIGURE 3. ACCESS FOR THE REPAIR
SHEET 1 OF 4  737-53A1196

### Page 35 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
SEE DETAIL 111 5
•L 190
S-18A
S-19
) SEE DETAIL III
S-20
DETAIL II
LEFT SIDE SHOWN
RIGHT SIDE SIMILAR
#07443
FIGURE 3. ACCESS FOR THE REPAIR
Jun 30/94  SHEET 2 OF 4  737-53A1166
33

### Page 36 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
5
- UL 190
S-18A
S-19
- S-18A
DETAIL III
_ STA
727
VIEW B-B
VIEW A-A
FIGURE 3. ACCESS FOR THE REPAIR
SHEET 3 OF 4  737-53A1166

### Page 37 (OCR)

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  Keep  Remove/  Flap Right Angle  Gearbox  Refer to AMM 27-51-261.  Keep the parts to use again.
2  Remove/  Tee  65-48692-5 Left Side  1  Keep the tee to use again.
Keep  65-48692-12 Right Side
Keep  Remove/  Bracket  69-39437-2 Right Side  69-39436-2 Left Side  Keep the bracket to use again.
4  Trim  Shear Beam Web  65-46877-()  Trim the aft part of the outboard
vertical side of the Shear Beam
Web to allow for the installation
of the Repair Angle.
Apply  (Alodine)  Treatment  Chemical Film  Structural Repair Manual  51-10-2  Apply to cut area. Refer to 737
Apply  Primer  BMS 10-11, Type 1  Apply one layer to cut area.
5  Trim  Horizontal  65-46547-()  1  Trim the outboard part of the
Stiffener  vertical side of the Horizontal
Stiffener to allow for the
installation of the Repair Angle.
Apply  | (Alodine)  Chemical Film  Treatment  51-10-2  Apply to cut area. Refer to 737  Structural Repair Manual
Apply  Primer  BMS 10-11, Type 1  Apply one layer to cut area.
FIGURE 3. ACCESS FOR THE REPAIR
Jun 30/94  SHEET 4 OF 4  737-53A1166
35

### Page 38 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
VIEW A-A
FIGURE 4. MAKE THE REPAIR PARTS
Jun 30/94  SHEET 1 OF 3  737-53A1166
36

### Page 39 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
R07515
FIGURE 4. MAKE THE REPAIR PARTS
Jun 30/94  SHEET 2 OF 3  737-53A1166
37

### Page 40 (OCR)

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 part.  equivalent airplane parts. Make sure that the fastener hole edge margin is not less than the
STEP  TASK  NAME  MATERIAL  QTY  NOTES
Make  Repair Angle  AND10134-2008 × 20.8  1
7075-T6,
or equivalent.
2  Make  Shim  1.25 × 4.25 × 0.032 inch thick  1
7075-T6 Aluminum Alloy Sheet.
Make  Repair Strap  1.25 × 6 x 0.18 inch thick  1
7075-T6 Aluminum Alloy Sheet.
4  Make  Filler  1.4 x 8.2 x 0.18 inch thick
7075-T6 Aluminum Alloy Sheet.
5  Make  Filler  1.2 × 1.4 × 0.82 inch thick
7075-T6 Aluminum Alloy Sheet
6  Make  Repair Angle  4 × 8.2 x 0.15 inch thick  Refer to 737 Structural
7075-TO Aluminum Alloy Sheet.  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
Bend  Vertical Wall  Also, bend the vertical wall
so it will align with the filler
made in Step 4 and the
Repair Angle made in Step
Heat Treat  Repair Angle  Heat treat to T-6.
7  Make  Shim  2.1 × 11.4 x 0.18 inch thick
7075-T6 Aluminum Alloy Sheet.
8  I Make  Shim  1.2 x 8.7 x 0.18 inch thick  1
7075-T6 Aluminum Alloy Sheet.
FIGURE 4. MAKE THE REPAIR PARTS
Jun 30/94  SHEET 3 OF 3  737-53A1166
38

### Page 41 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
SEE DETAIL 11
SEE DETAIL I
12
DETAIL I
FLAP RIGHT ANGLE GEARBOX
RIGHT GEAR BOX SHOWN
LEFT GEARBOX SIMILAR
FIGURE 5. INSTALL THE REPAIR
Jun 30/94  SHEET 1 OF 5  737-53A1166
39

### Page 42 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
WL 190
S-18A
S-19
S-20
INBO
DETAIL II
LEFT SIDE SHOWN
RIGHT SIDE SIMILAR
FIGURE 5. INSTALL THE REPAIR
SHEET 2 OF 5  737-53A1166
40

### Page 43 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
STA
727
FWD
VIEW A-A
FIGURE 5, INSTALL THE REPAIR
SHEET 3 OF 5  737-53A1166
41

### Page 44 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
STA
727
- S-18
- S-18A
$-19 -
- 5-20
VIEW B-B
LOOKING OUTBOARD
FIGURE 5. INSTALL THE REPAIR
Jun 30/94  SHEET 4 OF 5  737-5341185

### Page 45 (OCR)

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
Install  Repair parts  Temporarily install repair parts.
Drill  Fastener holes
Remove  Hepair parts
Deburr  Fastener holes  Remove sharp edges.
Apply  Chemical film  Refer to 737 Structural Repair
treatment (Alodine)  Manual 51-10-2.
Apply  Primer  BMS 10-11, Type 1
2  Install  Repair Angle  (refer to Figure 4, Step 1)  1  Install parts with BMS 5-95 fay
Install  Shim  (refer to Figure 4, Step 2)  1  surface sealant. Refer to 737  Structural Repair Manual
4  Install  Repair Strap  (refer to Figure 4, Step 3)  1  Install with BACB30 MB  51-20-4.
5  6  Install  Install  Filler  Filler  (refer to Figure 4, Step 4)  (refer to Figure 4, Step 5)  1  use oversize fasteners.  fasteners the same size as  was removed. If necessary,
7  Install  Repair Angle  (refer to Figure 4, Step 6)  1  For new fastener locations, use  BACB30MB8-() fasteners.
8  Install  Shim  (refer to Figure 4, Step 7)  1  Install fasteners wet with BMS
5-95 sealant.
9  Instali  Shim  (refer to Figure 4, Step 8)  1
10  Install  Bracket  69-39436-2 Left Side  1  Install the bracket removed in
69-39436-2 Right Side  Step 3 of Figure 3.
11  Install  Tee  65-48692-5 Left Side  1  Install the tee removed in Step
65-48692-12 Right Side  2 of Figure 3.
12  Install  Flap Right Angle  1  Install the Flap Right Angle
Gearbox  Gearbox removed in Step 1 of
Figure 3.
Refer to AMM 27-51-261.
FIGURE 5. INSTALL THE REPAIR
SHEET 5 OF 5  737-53A1166
43

### Page 46 (OCR)

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
25.571, as amended in 1978, to ensure safe operation of 737 airplanes throughout their operational life.  Aviation Administration (FAA) Advisory Circular 91-56 in accordance with Federal Aviation Regulation (FAR)
failure of the outboard chord of the frame at BS 727.  their reaching critical lengths. Failure to detect cracks prior to their reaching critical length may result in  Inspection Program and the Compliance Section, that are recommended for the detection of cracks prior to  Table I provides a summary of the inspections specified in Accomplishment Instructions, Part I - Flight Safety
regulatory agency.  Any cracked structure should be replaced prior to further flight unless specifically approved by your cognizant
described in the addendum.  Please report any discrepancies to Boeing Customer Support Engineering using the reporting system
Jun 30/94
ADDENDUM
Page 1 of €

### Page 47 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
TABLE I - CHORD INSPECTION
Inspection  Airplane Condition  Inspection Threshold  Repeat Inspection
Destructive Test  (See 737 Non  (Flight Cycles)  until Preventive  Interval (Flight Cycles)
Manual)  Modification is installed
Close visual inspection  Service Bulletin
of the the outboard  Modification not
chord of the frame at  accomplished.  27,000 to 50,000 (a)  15,000 (e)
BS 727. Examine the  Service Bulletin
edge of the forward  737-53-1088 frame
flange.  replacement not
accomplished.
Pulse Echo Shear  50,000 to 60,000 (b)  7,500 (0)
Wave inspection of the  or
outboard chord of the
frame at BS 727.  Service Bulletin
Examine area where  Stringer 18A is  accomplished.  Modification not  60,000 to 70,000 (c)  5,000 (g)
attached.  Lower part of frame
replaced per Service
High Frequency Eddy  Bulletin 737-53-1088.  70,000 (d)  3,000
Current inspection of
the frame at BS 727.  the outboard chord of  Examine two fastener  holes (i) i).  Service Bulletin  Modification not  accomplished.  Upper part of frame  chord was replaced).  30,000 (after the  replaced.  Use the intervals shown  after the chord was  above for flight cycles
High Frequency Eddy  Current inspection of  replaced per Service  Bulletin 737-53-1088.
the outboard suriace
of Stringer 18-A.
Examine around the
heads of two fastener
holes.
Close visual inspection  Service Bulletin  Next scheduled  Use your Maintenance
chord of the frame at  of the the outboard  Modification  accomplished.  Refer to the 737  structural inspection.  scheduled structural  Program Interval for
BS 727. Examine the  Maintenance Planning  inspections.
edge of the forward  Data Manual  Refer to the 737
flange. (h)  D6-17594-2, Section  Maintenance Planning
6-02.  Data Manual
D6-17534-2, Section
6-02.
Jun 30/94  ADDENDUM
Page 2 of 6

### Page 48 (OCR)

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.
(1) 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.
0) 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
Page 3 of 6

### Page 49 (OCR)

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
Page 4 of 6

### Page 50 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
DISCREPANT STRUCTURE REPORT  SIDE 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. _  FUGHT HOURS  FLIGHT CYCLES _
COMPONENT DATA (AS APPLICABLE AND AVAILABLE):
NAME  P/N  SAN
IPC/DWG. REF.  SAM REF.
COMPLETE THE FOLLOWING IF KNOWN AND DIFFERENT FROM SECTION 2:
COMPONENT FUGHT HOURS SINCE NEW _  SINCE OVERHAUL
COMPONENT FLIGHT HOURS SINCE NEW _  SINCE OVERHAUL
4  REPAIR DATA  PLANNED  COMPLETED
4A  ACTION
48  REFERENCE ASSOCIATED WITH INSPECTION/REPAIR (SPECIFY NO., PAGE, FIGURE, ETC):
SB  AD_  IPC  SRM
MPO  OTHER (E.G. SDR, MRA)  SILA
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
HOURŞ  FLIGHTS
HOUAS  FLIGHTS
HOURS  FLIGHTS
6  INSPECTION DATA (COMPLETE KNOWN INFO., CHECK APPROPRIATE ITEMS FOR DISCREPANT STRUCTURE):
CURRENT INSPECTION INTERVALS (FUGHTS) .
CORRESPONDING INSPECTION LEVELS
6A  WHEN DISCOVERED  6B  INSPECTION LEVEL  6C  DETECTION METHOD
SCHEDULED MAINTENANCE  WALK - AROUND  • VISUAL
OVERHAUL  GENERAL VISUAL  • MAG. VISUAL  SOUND
SPECIAL/DIRECTED (AD, SB...)  UNSCHEDULED  INTERNAL SURVEILLANCE  EXTERNAL SURVEILLANCE  1] DYE PENETRANT  • ULTRASONIC  1 SMELL  • FEEL
SYMPTOM (FUEL/PRESS LEAK...)  DETAILED  || LOW  X-RAY
• RELATED FLEET EXPERIENCE  SPECIAL  FREQUENCY  • PRESS. LOSS
ACCIDENT INVESTIGATION  EDDY CURRENT
SSID  I HIGH
• SERIES 50  FREQUENCY
EDDY CURRENT
| BORGNETICE  MAGNETIC
PARTICLE
Jun 30/94  ADDENDUM
Page 5 of 6

### Page 51 (OCR)

BOEING SERVICE BULLETIN 737-53A1166
DISCREPANT STRUCTURE REPORT  SIDE 2
DISCREPANCY DESCRIPTION:
Attach sketch, photos and text as required to describe defect and specific location. When applicable give detaib of associated
discrepancies on the same arcraft, related experience with this discrepancy on any aircraft, and previous modification (s) to the  discrepant structure.
7A  TYPE OF DISCREPANCY:
I BENT  BROKEN  1 CORRODED  I CONTAMINATED  I DENTED  DETACHED  ) LOOSE  MISSING  • WRINKLED
1 BUCKLED  • CRACKED  • IMPROPERLY  • OUT-OF-TOLERANCE
I CLOGGED  BURNED  | DELAMINATED  DEFORMED  I LEAK  ADJUSTED  • WORN  STUCK
78  SIZE OF DISCREPANCY:  • INCHES, OR  • CENTIMETERS
AREA_  DEPTH _
CRACK LENGTH INITIALLY DETECTED  DATE _
FINAL MEASUREMENT (IF DIFFERENT) _  DATE
7C  DISCREPANT PART:
• FRAME/BULKHEAD  PRESSURE BULKHEAD  CC  PLATE/PANEL  SKIN  JOINT/SPLICE  LUG
FRAME AROUND OPENING  CHORD  • WELD
WINDOW FORGING  STRINGER NO.  BOND
KEEL BEAM  BEAM  OPEN HOLE
FLOOR  STRUT/BRACE  FASTENER HOLE
| SPAR  WING DRY-BAY AREA/COMPT.  WING CENTER SECTION  LONGERON  FITTING  UNK/ROD  CUT-OUT  ACCESS/LIGHTENING HOLE  NOTCH/GROOVE
| LANDING GEAR BEAM  | FLAP TRACK  | STOP  BRACKET/CUP  FASTENER  BASIC MATERIAL  DISCONTINUITY  BUSHING
FAIRING
PIN
70  LOCATION OF DISCREPANT PART:
GENERAL LOCATION (E.G., BILGE, UNDER GALLEY)
| NACELLE/PYLON  I BODY STA NO..  • NOSE LANDING GEAR  • WING STA. NO  • HORIZ.STAB.STA  I VERT. STAB. STA  COMPARTMENT  | DOOR/ACCESS PANEL  •• RUDDEF  AILERON  SLAT  ELEVATOR  FLAP  INTERIOR  INBOARD  LEADING EDGE  LEFT  FORWARD  UPPER  ENTER ARE  | LOWER  OUTBOARD  RIGHT  AFT  TRAILNG EDGE
• MAIN LANDING GEAR  • WING LANDING GEAR  TAB (ALSO CHECK ABOVE)  SPOILER  1 SPECIFIC LOCATION  MIDDLE  SIDE
• BODY LANDING GEAR
INSPECTED BY  REPAIRED BY
ORIGINATED BY
DATE
Jun 30/94
ADDENDUM
Page 6 of 6

### Page 52 (OCR)

BOLINO  Airplane  Commercial  737
Group  Service Bulletin
Date:  Number:  June 30, 1994  737-53A1166  Evaluation Form
ATA System: 5311
Prepared By: Maurice Chatwin
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
items:  that you give us to improve the quality of our service bulletins. Please include data about these or other
- Did this service bulletin meet your estimate of quality?
- How easy is this service bulletin to understand?
- Will you do this service bulletin fully? If not, please tell us why.  - Are the Planning Information, Material Information and Accomplishment Instructions satisfactory?
- 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:
form.  If you have other comments please use the other side. Thank you for the time you used to complete this
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 2L-02
Seattle, WA 98124-2207
BOEING COMMERCIAL AIRPLANE GROUP P.O. BOX 3707 SEATTLE, WASHINGTON 98124-2207
Page 1 of 1

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