## sofV--O Commercial Airplane 

# 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 inspection again. Do the inspection at the times given inthe Compliance section until the preventive Four operators sent reports of cracks in the modification is installed. If the preventive outboard chord of the frame at Body Station (BS) modification is installed, no more inspections per 727 where Stringer 18A is attached. The reports thisbulletin are necessary. were of eight airplanes with 39,000 to 54,100 flight hours and 56,200 to 73,200 flight cycles. The More work is necessary for operators that have cracks were caused by fatigue that was started by replaced the outboard chord of theframe at BS 727 fretting of adjacent parts. Operators have also sent as shown in Service Bulletin (SB) 737-53-1088 reports of cracks inthe outboard chord of Stringer (referto Compliance). 1

8-A. COMPLIANCE The changes shown in this service bulletin will decrease the probability of these cracks. This area This bulletin has a Flight Safety Inspection Program is a primary structural element. Operation with that isthe minimum necessary tokeep thestructural cracks in the frame will decrease the structural integrityoftheoutboard chord. integrityofthis area. Forairplanes with 27,000flights to50,000flights, do As part of a service bulletin validation program, the the inspection initially within 4,500flights after you inspection, frame chord replacement, and preventive get this bulletin. Do the inspection again at intervals modification was completed on airplane PG576 of 15,000 flights untilthe airplanecollects more than (Group 2)beforethe initial releaseofthis bulletin. 50,000flights. ACTION For airplaneswith 50,000 flightsto 60,000flights, do the inspection initially within 2,500 flights after you Make an inspection of the outboard chord of the get this bulletin. Do the inspection again at intervals frame at BS 727 where Stringer 18A is attached. of 7,500 flights until the airplane collects more than Look for cracks. Do the inspection at the times 60,000flights. given inthe Compliance section. For airplaneswith 60,000flightsto 70,000flights,do Also, make an inspection of the outboard chord of the inspection initiallywithin 1,500 flights after you Stringer 18A at Station 727. Ifcracks are found in get this bulletin. Dothe inspection again at intervals the outboard chord of Stringer 18A, get repair of 5,000 flights until the airplane collects more than instructionsfrom Boeing. 70,000flights. If cracks are found in the outboard chord of the For airplanes with more than 70,000 flights, do the frame at BS 727, install the time limited repair or inspection initiallywithin 500 flights afteryou get this replace the chord and, optionally, install the bulletin. Do the inspection again at intervals of preventive modification. If no cracks are found, 3,000flights. install the preventive modification or do the

BOEING COMMERCIALAIPLANE GROUP P.O. BOX 3707 8EATTLE WASHINGTON YR24-2207 

### Summary Page 1 

### of 2

## BOEING SERVICE BULLETiN737-53A1166

For airplanes with the lower part of the chord EFFECTIVITY replaced by SB 737-53-1088, do the inspection at theintervals shown above. All 737-100 and 737 -200 airplanes. Line Numbers 1-999, in 4groups. For airplanes with the upper part of the chord replaced by SB 737-53-1088, do the inspection MANPOWER initially within 30,000 flight cycles after the chord was replaced. Do the inspection again at the Referto Paragraph I.F. Manpower. intervals shown above for flight cycles after the chord was replaced. MATERIAL INFORMATION Boeing Supplied Kits Refer to Paragraph k.G.. Material
- Price and Availability.

EXAMINE AREA AROUND

STRINGER 18-A TWO FASTENER HOLES (ON SOME AIRPLANES STA THE OUTER CHORD OF 727 STRINGER 18-A IS A FLAT STRAP) 

## 000
TYPICA 0 

### 0 C

RACK



## 00 EXAMINE FORWAR EDGE OF FLANGE 

### 0 0

EXAMINE SURFACE OF S-18A AROUND TWO FASTENER HEADS

LEFT SIDE SHOWN RIGHT SIDE OPPOSITE (WIN6-TO-BODY FAIRING NOT SHOWN)

Jun 30/94 Summary Page2 of 2

### D -XfW- 

### O Commercial 

## Airplane 

# 737 Group 

# Service Bulletin-ALERTNumber: 737-53A1166 Date: June30. 1994 ATA System: 5311

SUBJECT: FUSELAGE

- FRAMES

- BODY STATION 727 OUTBOARD CHORD AT STRINGER 1 8A, 

### INSPECTION AND PREVENTIVE MODIFICATION
THIS SERVICE BULLETIN ISSENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH l.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR, IFAPPLICABLE 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. Thisservice bulletin isforthe airplanesshown below. IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER AER LINGUS (ARL)

2 PG255 PG573 PY322 3 PK029 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)

3 PK361 PK631 PK633-PK634 PL717-PL725 PY051-PY053

Jun 30/94 737-53A1 166 Page 1 of 44

## 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 PY651 AIR MADAGASCAR (MAD)

2 PG375 3 PL793 AIR MALTA (MLT)

3 PL621-PL623 AIR NAURU (NAU)

3 PK356 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 PY1il PY113 ALASKA AIRLINES (ASA)

3 PY112 PY134-PY135 PY270 PY461-PY462 ALBATROS AIRLINES (ABS)

2 PG251 PG253 ALL NIPPON AIRWAYS CO.LTD. (ANA)

2 PG584-PG586 3 PK711-PK716 ALOHA (ALO)

2 PG046 3 PK286-PK287 PK691-PK695 PK697 PY231 PY242 PY451 AMC AVIATION (AMF)

3 PK264

Jun 30/94 737-53A1 166 2

## BOEING SERVICE BULLETIN 737-53A1166

AMERICA WEST AIRLINES, INC. (AMW)

2 PC004 PG036 PL801 3 PK283 PK696 PLO81 PL172 PL551-PL562 AMIRI FLIGHT (ABD)

3 PK495 ANGOLA AIRLINES (ANG)

3 PK661 PK664 PY162 ANSETTWORLDWIDE AVIATION SERVICES (AWW)

1 PA001 PA003-PA004 2 PCO03 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 BHOJAAIR (BHO) 3 PK614 BOURAQ INDONESIA AIRLINES (PTB)

2 PJQ01 PL742 PL803 3 PK501 PL743-PL744 BRAATHENS S.A.F.E. (BRT) 3 PK882 BRITISH AIRWAYS (BAB)

3 PK731-PK749 PK771-PK772 PK774-PKm PK779 PNO01 CALDWELL AIRCRAFT TRADING CO. (CAS)

2 PG402 CAMEROON AIRLINES (CAM)

2 PY046-PY047

Jun 30/94 737-53AI1 66 3

## 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 PA01 1 PG199 2 PA012 PA014 PA016-PA020 PG056 PG064 PG225 P0433 PG501-PG505 PG621-PG625 PG627-PG628 PG630 PG704 3 PLO00l 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 PNO81-PNO82 DELTA AIR LINES, INC. (DAL) 3 PK611 PK613 PK623-PK624 PK632 PL221 PL611 4 PN131-PN13S EG 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 30/94 737-53A1 166 

### 4

## BOEING SERVICE BULLETIN 737-53A1166
EDRESS, SHIEKH M. (SME) 3 PL505 EGYPTAIR (EGP)

3 PK255 PK257-PK258 ELAL ISRAEL AIRLINES, LTD. (ELA)

3 PL631-PL632 EURALAIR (ERA)

2 PG026 PGO28-PG029 PY004 PY006 FAR EASTERN AIR TRANSPORT (FAT)

I 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 P0274 FORTUNE AVIATION (FOR)

3 PK432 FRENCH POSTAL OFFICE (FPO)

2 PY302 PY344 3 PY101-PYl03 FRONTIER AIRLINES (FRO)

2 PG306 PG308 GATARI AIR SERVICE (GRI)

3 PL441 GB AIRWAYS (GBA)

3 PJ11O-PJiii 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 PK354-PK355 GULF AIR (GUL)

3 PK464 PK467-PK468 HAPAG LLOYD (HAP)

3 PL504

Jun 30/94 737-53A1 166 5

## 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 PHO21 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 INTERAMERICA S.A. DE C.V. (INJ)

2 PL761 INTERNATIONAL AIR LEASES (IAL)

2 PG043 PGO47-PGO48 INTERNATIONAL AIRLINE SUPPORT GROUP (ASG)

2 PG021 INTERNATIONAL PACIFIC TRADING CO. (IPT)

2 PG224 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 PY005 KENYA AIRWAYS (KEN)

3 PK253 PK256 LACSA (LAC) 3 PK357 PK871 LADECO (LDE) 2 PL802 3 PJ004-PJ006 PK212 PK281 PK826 PK830 LAN-CHILE S.A. (LAN)

3 PK360 PK825 PL025 PL028

Jun 30/94 737-53A1 166 6

## BOEING SERVICE BULLETIN 737-53A1i66

LAPA (LAZ) 2 PG355 3 PK047 PK051 PK463 LINA CONGO (LNA)

3 PY411 LINHAS AEREAS DE MOCAMBIQUE (LAM)

2 PH703 PY031 LITHUANIAN AIRLINES (LIJ)

3 PK563 LUFTHANSA GERMAN AIRLINES (DLH)

2 PY345-PY346 3 PK901-PK903 PK905 PK911-PK927 PK929-PK931 MALEV HUNGARIAN AIRLINES (HGA)

3 PK284-PK285 PK827 MANDALA AIRLINES (MND)

3 PK874 PLO27 PLO61 PL421 PNO02 MARKAIR, INC. (ALK)

4 PY056-PY057 MIDAIR (MAI)

2 PY342 MODILUFT (MOU)

3 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 PL784-PL788 NORDAM (NOP)

3 PK221 NORDIC EAST (NOE)

2 PJ002 NWT AIR (NTA)

2 PX701 3 PY132-PY133

Jun 30/94 737-53A1 166 

## 7

## BOEING SERVICE BULLETIN 737-53A1166

OLYMPIC AIRWAYS (OLY)

3 PK301-PK304 PK307-PK310 PM021-PM023 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 PK026-PK028 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 PK041 PK044-PK046 PK048-PK050 PK052-PK053 PK431 PK433 PY272-PY275 SAETA S.A. (SAE)

3 PK211 PK213 SAHARA INDIAN AIRLINES (SAQ)

3 PK820 SAHSA (SERVICIO AEREO DE HONDURASS.A.) (SAH)

2 PJ032 PJ071 PL736 SAUDI ARABIAN AIRLINES CORP. (SVA)

2 PL728-PL728 PY036-PY037 3 PK311-PK317 PL729-PL735 SAUDI ROYAL FLIGHT (SRF)

3 PK318 SERVICIOS AEREOS RUTAS ORIENTE, (SARO) (SEV)

2 PA015 PA021-PA022 3 PK351 PK353 SHAHEEN AIR INTERNATIONAL (SHK)

3 PK514

Jun 30/94 737-53A1 166 8

## BOEING SERVICE BULLETIN 737-53A1166

SHANNONAIR LEASING LTD. (SLE)

3 PK352 SIERRA PACIFIC AIRLINES (SRP)

3 PK627 SOUTH AFRICAN AIRWAYS (SAA)

2 PG353 3 PL101-PL113 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 PNO83 4 PN084-PNO86 TACA INTERNATIONAL AIRLINES, INC. (TAC)

2 PG059 PG352 3 PK223 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 INTERNATIONAL, INC. (TII)

3 PK511 TRANSAERO (TRX)

3 PK451-PK452 PK773 TRANSAVIA AIRLINES (TAV)

2 PG074 3 PK502-PK504 PK821 TRANSMILE AIR SERVICES (TML)

2 PY323 PY381 TUNIS AIR (TUN)

3 PK861-PK863 PY621 UNITED AIR LINES, INC. (UAL)

1 PGO01-PGO04 PGO06-PGO08 2 PGO09-PGO13 PGO15-PGO19 PG022-PG025 PG027 PGO30 PG032-PG033 PGO38-PGo4o PG045 PGO51-PGo54 PG057 PGO60-PGO63 PGO65-PG072 PG075 3 PK201-PK202 PLC02-PL023 UNITED STATES AIR FORCE (USF)

3 PJ201-PJ219

Jun 30/94 737-53A1 166 9

## BOEING SERVICE BULLETIN 737-53A1166
USAIR, INC. (USA)

2 PGO41-PG042 PG073 PG206 PG301 PG303-PG304 PG307 PG309-PG311 PG313-PG314 PG474 PG576 3 PK288-PK289 PK591-PK599 PK601-PK610 PK883 PM101-PM117 PNO21-PN028 4 PM1 18-PM119 PN029-PN038 USL CAPITAL (USL)

2 PY001 VARIG AIRLINES (VAR)

3 PK111-PK116 PK118-PK120 PK141-PK146 PL453-PL454 VARSA (VAB)

2 PC-351 VASP (VSP)

2 PG435 PG437 PG439-PG440 PG471-PG473 PL756 PX071 3 PHC11-PHO13 PK061-PK062 PK065-PK067 VENEZUELA

- GOVERNMENT OF (VNZ)

3 PK070 VISCOUNT AIR SERVICE INC. (VAS)

2 PG201 PG203 PG209 PG212 PG216-PG217 PG220-PG222 PJ1O1 PJ103 3 PK305-PK306 WHIRLPOOL FINANCIAL CORP (ZZW)

2 PG214 XIAMEN AIRLINES CO. LTD. (XIA)

3 PK635 YEMEN AIRWAYS (YEM)

3 PK341 ZAMBIA AIRWAYS (ZAM)

3 PK291 PL026 IDENTIFICATION BY VARIABLE NUMBER GROUP 1 PA001-PA01 1 PA099 PGOO1-PG008 PG199 PG271-PG272 GROUP 2 PA012-PA022 PA231-PA232 PCO01-PCO05 PG009-PGO75 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

Jun 30/94 737-43A1 168 10

## BOEING SERVICE BULLETIN 737-53A1166

GROUP 3 PH001 PHO11-PHo13 PHO21-PH024 PH743 PJ003-PJ009 PJ105-PJ119 PJ201-PJ219 PK026-PK029 PK041-PK053 PK061 -PK070 PK081-PK082 PK091-PK099 PK101-PK103 PK1 1 1-PK120 PK141-PK146 PK201-PK204 PK21 1-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 PKS11-PK514 PK521-PK525 PK541-PK564 PK5S81 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 PLO01-PL028 PLO61 PLO81 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-PL74S PL758 PL762-PL770 PL781-PL788 PL793 PM001-PM006 PM021-PM023 PM051-PM062 PM101-PM117 PM141-PM142 PNO01-PNO02 PNO21-PN028 PNO81-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-PNo38 PN084-PNO86 PN131-PN135 PY056-PY057 PY672 2. Spares 

### None



# 0

Jun 30/94 737-53A1166 11

### BOEING SERVICE BULLETIN 737-53A1166

B. Reason 

### Boeing Supplemental Structural Inspection Document D6-37089, Section 8.2. SSI Number F.29, is related tothis service bulletin. Boeing Structural Item Interim Advisory (SIIA) 737-131 isrelated to thisservicebulletin. The changes shown inthisservicebulletinwill decreasethe probabilityofcracks intheframe at Body Station (BS) 727 where Stringer 18A is attached. This area is a primary structural element. Operation with cracks inthe frame will decrease the structural integrity of this area Unscheduled downtime can be necessary to replace aframe that has acrack. Four operators sent reportsofcracks inthe outboard chord oftheframe at BS727. 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 inthe chord at the lower row of fasteners where Stringer 18A isattached. The cracks were ina forward and aft direction and measured approximately 1.4 to 3.0 inches inlength. The cracks were caused by fatigue that was started by fretting of adjacent pans. Operators have also sent reports ofcracks in the outboard chord of Stringer 1 8-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 theconfiguration of aGroup 2airplane. C. Description The airplane effectivity isdivided in4 groupsbecause of differences inairplane configuration. There isapreventive modification kitfor each oftheairplane configurations. Do the inspectionsthat followatthetimes given in the Compliance section. Make a visual inspection of the edge of the forward flange of the outboard chord oftheframe at BS 727. Look forcracks. Make an inspection of the outboard chord under Stringer 18-A. Use the Pulse Echo Shear Wave (PESW) Inspection procedure. Look for cracks inthe areaofthe two forward lower fastener holes in thechord where Stringer 18A isattached. NOTES: 

### 1. Airplanes with 60,000 to 70.000 cycles can omit the next step only at the initial inspection at 1500 flights afteryou getthis bulletin. 2. Airplanes with more than 70.000 cyclescan omit the next step only at the initial inspection at 500 flightsafter you getthis bulletin. Remove the two forward lower fasteners. Make an inspection ofthe fastener holes inthe outboard chord of BS 727. Use ahigh frequency eddycurrent (HFEC) inspectionprocedure. Look forcracks. 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 forcracks. Ifcracks are found inthe outboard chord of Stringer 1

8A, get repair instructionsfrom Boeing. Ifcracks are found inthe outboard chord of the frame at BS 727, install the time limited repair or replace the chord. Referto Boeing Service Bulletin 737-53-1088 for instructionsto replacethechord. When you replace the chord, Boeing recommends that you also install the preventive modification. Attheoperators option, the preventive modification can be installed later.

Jun 30/94 737-53A1 166 12

### BOEING SERVICE BULLETIN 737-53A1166

The repair istime 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 nocracks are found, installthe preventive modification or dothe 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 service bulletin, are 

### necessary. More work is necessary foroperators that have replaced the chord as shown inService 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 qualityof 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 inthis 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 thechanges given inthis service bulletin. 3. The changes given in Boeing Service Bulletin 737-53-1076, "Fuselage

- Circumferential Butt Splices and Bonded Doublers Inspection, Repairand Modification", can be made on applicable airplanes beforeor duringthe changes given inthis 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 duringthe changes given in thisservice bulletin. 5. The changes given inBoeing 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 inthisservice 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 andl016", can be made on applicable airplanes before or during the changes given inthis servicebulletin. PLEASE SEND A REPORT OF YOUR INSPECTION PROGRAM. ALSO, SEND THE INSPECTION RESULTS WHEN EACH INSPECTION IS COMPLETE. REFER TO THE FLIGHT SAFETY SECTION 

### INTHE ADDENDUM,

Jun 30/94 737-53A1 166 13

## BOEING SERVICE BULLETIN 737-53A1166

D.Compliance This bulletin has a Flight Safety Inspection Program that isthe minimum necessary to keep the structural integrityofthe outboard chord. For airplanes with 27,000 flights to 50,000 flights, do the inspection initiallywithin 4,500flights after you get this bulletin. Do the inspection again at intervals of 15,000 flights until the airplane collects more than 50,000flights. For airplanes with 50,000 flights to 60,000 flights, do the inspection initially within 2,500flights after you get this bulletin. Do the inspection again at intervals of 7,500 flights until the airplane collects more than 60,000flights. 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 70,000flights. For airplanes with more than 70,000 flights,do the inspection initiallywithin 500 flights after you get thisbulletin. Dothe inspection again at intervals of 3,000flights. For airplaneswith the lower part of the chord replaced by SB 737-53-1088, do the inspection at the intervalsshown above. For airplanes with the upper part of thechord 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 flightcycles afterthe chord was replaced. E. Approval This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified inthis 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 FM approved Boeing changes and do not apply to airplanesonwhich other configuration changeshave been made.

Jun 30/94 737-63A1 166 14

## 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 estimatewith operator man-hour data ifnecessary. The estimate does not include lost time. Theseare some examples of lost time:

- Timeto adjustto theworkplace

- Time toschedulethe work

- Time to examinethework

- Timeto curethe materials

- 

### Timeto make theparts

- Timeto find thetools. Inspection only. Task Number of Persons Man-Hours Elapsed Time (Hours) Open Access Inspection 1 1.5 1.5 Close Access 1 1 1 TOTAL FOR iNSuEClTiON 

### 3.5 Time Limited Repairforthe 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 2 40 20 Modification Close Access 2 27 13.5 TOTAL FOR MODIFICATION 99 49.5

Jun 30/94 737-53Al166 15

## BOEING SERVICE BULLETIN 737-53A1166

G. Material
- Price and Availability Boeing can supply the kitsshown in Paragraphs 1I.A., Parts Necessary For Each Airplane as shown below. Kit availability isshown inthe Reorder Lead Time (ROLT). ROLT iscalculated from the date Boeing getsthe purchase order. ROLT Unit Pricethru Kit Number Name (weeks Sep 16/94 65C37277-1 Top Kit, Left Side 32 $1759 65C37277-2 Top Kit, Right Side 32 $1759 65G37277-3 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: Net30 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 1.Welghtand Balance Change in Weight Change in Moment Task (Pounds) (Pound-Inches) 

### +() () Preventive Modification +3.7 +2690 Repair +6.5 +4755

Jun 30194 737-53A1 116 

### 16

## BOEING SERVICE BULLETIN 737-53A1166

J. References * 1. Existing Data: a. 737 Maintenance Manual Subjects26-21-11, 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 NondestructiveTest Manual D6-37239, Part 4,Subject 53-10-01 d. 737 NondestructiveTest 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. Datasupplied withthisservice bulletin: a. Drawings: DrawingNumber Sheet DCN ADCN Title 65C37277 PL

- 1 Strap Installation

- Station 727 Bulkhead, 1

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

### 3. Installation Drawings: Drawing Number Title 65-48654 Frame Installation

-Aft Wing/Body Faking, Station 729.38 65-46877 Strap and Beam Installation

-Stringer 1 8A, Station 639 toStation 747 These drawings were used to prepare thisservice bulletin. These drawings are not necessaryto make the specifiedchanges, and are not suppliedwith this servicebulletin. These drawings may not be applicable to all airplaneconfigurations oroperators. 4. Process Data Boeing Process Specifications referred to on the drawings are not given inthis service bulletin sincetheseprocedures arefrequently used asstandard shop practices. K. PublicationsChanged Publication Chanter-Section 737 Structural Repair Manual 53-10-2 737 Non-DestructiveTest Manual Part 4
L. Electrical Load Data Not changed

Jun 30/94 737-53A1 166 17

## 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 

### Quantitl Part Number Name

- 65C37277-5 (c)(e) Top Kit (Left Side)

- . 65C37277-6 (c) (e) Top Kit (Right Side) 65C37277-7 (d)(e) Top Ki (Left Side) 65C37277-8 (d)(e) Top Ki (Right Side)
a For Group 1 airplanes. b. For Group 2 airplanes. c. For Group 3airplanes. d. For Group 4airplanes. e. Referto Drawing 65C37277, sentwith thisbulletin, forthe list ofparts.

Jun 30/94 737-53A1 168 18

### BOEING SERVICE BULLETIN 737-53A1166

2. Parts and Materials Supplied bythe 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 8MS 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 bythe Operator ifthe Preventive Modification is notinstalled: NOTE: Refer to 737 Structural Repair Manual Chapter 51 for alternativefasteners. Quantity Part Number (Specification) Name 2 BACB30MB8A() (a)(b)(e) Hi-Lok 2 BACB30MC8A() (a) (c)(e) Hi-Lok 2 BACC3OX8 (a)(b)(c) Collar 2 BACB30MD8A() (a)(d)(e) Hi-Lok 2 BACC30AC8 (a)(d) Collar (a) Use ifthe chord isnot replaced and the preventivemodification is not installed. Use oversize fasteners if necessary (refer to Ill. Accomplishment Instructions). Only two fasteners are necessary ateach installation. Choosethe appropriate size. (b)Standard size. (c) For 1/64 oversize. (d) For 1/32oversize. (e) Choose the grip length thesameasthefastener that isremoved (referto Figure 1).

Jun 30/94 737-53A1 166 19

## BOEING SERVICE BULLETIN 737-53A1166

4. Parts and Materials Supplied by the Operator for the Time Limited Repair: The table that follows shows the repairparts necessary at each installation. NOTE: Referto 737 Structural Repair Manual Chapter 51 for alternativefasteners. Quantity Part Number (Specification) Name 

### 1 4x 8x0.15 inch thick 7075-TO Aluminum Alloy Sheet 1 AND10134-2008x 20.8, 7075-T6 Extruded Angle or equivalent 1 1.25 x4.25 x0.032 inch thick 7075-T6 Aluminum Alloy Sheet 1 1.25 x 6x0.18 inchthick 7075-T6 Aluminum AlloySheet 1 1.4x 8.2 x0.18 inch thick 7075-T6 Aluminum Alloy Sheet 1 2.1 x 11.4 x0.18 inch thick 7075-T6 Aluminum Alloy Sheet 1 1.2x8.7x0.18 inch thick 7075-T6 Aluminum Alloy Sheet 1 1.2x 1.4 x0.82 inch thick 7075-T6 Aluminum Alloy Sheet As necessary BMS 5-95, orequivalent 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 Toolsand 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 supplytomake sure all necessary tools are available. D. Existing Parts Accountability None

Jun 30/94 737-53A1 166 

### 20

### BOEING SERVICE BULLETIN 737.53A1166

Ill. 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 givethe recommended sequence ofsteps. 2. Unless shown differently, thesedimensions and tolerancesare 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 boltedge margin is plusor minus 0.05 inch

- 

### Angular tolerance isplusor minus 2degrees

- 

### Hole dimensions for standard solid rivets are given in737 Structural Repair Manual Chapter 51

- 

### Torque limitsto tighten nuts and boltsare given in737 Structural Repair Manual Chapter 51

- 

### Edge margins forfasteners are given in737Structural Repair Manual Chapter 51 3. Fastener installation isgiven in737 Structural Repair Manual Chapter51. 4. Alternative fasteners are given in737 Structural Repair Manual Chapter51. 5. Obeyall ofthewarnings and cautionsgiven inthespecified manual sections. Part I Flight Safety Insoection Proaram A. Dothe inspectionsthat follow at the thresholds specified inthe Compliance section. B. Fullyextend thetrailing edge flaps. Get accesstotheoutboard sideofthe frame at BodyStation (BS) 727 through the opening inthe flap fairing. At the operators option, for more access, remove the fairing forthe inboardtrack ofthe inboardflap. Keepthefairing and all fastenersfor installation. C. Get accessto 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 forthe gauge and thedetonator on theaft firebottle. D. Examine the outboard surface of the outboard chord of Stringer 18-A (refer to Figure 1). Look for cracks inthe surface around theheads ofthetwo fasteners immediatelyaft of BS727. E. Ifthere are cracks inthe outboard chord of Stringer 1 8-A, get repair instructionsfrom Boeing. F. Examine the edge ofthe forward flange ofthe outboard chord ofthe frame at BS 727 (refer to Figure 1). Look forcracks. G. Ifthereare nocracks intheforward flange oftheoutboard chord ofthe frame at BS727, go toStep H. Ifthere are cracks,goto 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 inthe areaofthetwo lower fastener holes (referto Figure 1). I. Ifno cracksare detected bythis procedure inthearea ofthe twolower fastener holes inthe outboard

chord ofthe frame at BS 727 ,

### goto Step J. Ifthere arecracks, goto Step L

Jun 30/94 737-53A1166 21

## BOEING SERVICE BULLETIN 737-53A1 168

NOTES: 1. Airplanes with 60,000 to 70,000 cyclescan omit Steps J and Konly at the initial inspection at 1500 flights after you get thisbulletin. 2. Airplanes with more than 70,000 cyclescan omit Steps J and Konly at the initial inspection at 500flights 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 1

8A is attached (refer to Figure 1). K. Remove thetwofasteners and inspectthe fastener holes for cracks asshown inFigure 1. L. Ifcracks are found inthe 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 thechord, 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. Ifthe crack extends past the second fastener holego toStep M. M. Replace the chord as shown in Boeing Service Bulletin 737-53-1088 (refer to Part 11 of the Accomplishment Instructions). When you replace the chord, Boeing recommends thatyou also install the preventive modification. At the customers option, the preventive modification can be installed later. Ifyou 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,dothe inspectionsagain as specified inthe Compliance section. N. Ifno cracks are found, install the preventive modification as specified in Part IIofthe Accomplishment Instructions or do the inspections again as specified inthe Compliance section. 0. If the preventive modification is not installed, replacethe fasteners removed in Step K (refer to Figure 1). If necessary, drill 1/64 or 1/32 inch oversizeto remove any damage (such as scratches, nicks, or ovality) inthe fastener holesand install oversize fasteners (refer to Section II.A.2. Parts and Materials Supplied by Operator). Do the inspections again, as specified inthe Compliance section, until the preventive modification is installed. NOTE: Check the fastener holes before they are oversized to see if theyare already oversize by the incorporation of another service bulletin. If another service bulletin has been installed, use the same size and type offastener used inthe 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 holesand install oversizefasteners. P. Ifdisconnected inStep C,install the connectorsforthe gauge and thedetonator on the aftfire bottle. Q. Ifremoved inStep B,Install the fairing forthe inboard track ofthe inboardflap. R. Return the airplane to serviceable condition.

Jun 30/94 73743A1 166 22

## BOEING SERVICE BULLETIN 737-53A1166

S. Send a report of the inspection to Boeing (refer to Paragraph C. Description and the Flight Safety Section inthe Addendum). 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 accesstotheoutboard side ofStringers S-18A and S-19 from BS 709to BS 747 (for 737 -100 airplanes) or 727A (for 737-200 airplanes). Referto Figure 2. To get the access, remove the parts that follow:

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

.The fairing support structure at 8S 727 (refer toView 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 inthe aft lower lobe. NOTE: On some airplanes there may be an auxiliary fuel tank installed. If installed, remove the auxiliary fueltank to get accesstothe cargo liner (referto737 AMM 53-23-1). C. Inthe wheelwell, get accesstothe inboard side of Stringer S-18A between BS 709 and 727. D. Inthe wheel well, get access to the inboard side of the outer chord at BS 727. To get the access, remove the engine fireextinguisher 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 Ri, 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 RI 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 thepreventive modification asshown in Drawing 65C37277. NOTES: 1. At the customers option make the external strap, 69-78770-1, -2 opposite, from 4130 150-170 KSlor 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 sametaper ratio. F. install the cargo linerif thatwas removed in Step B. Ifremoved inStep B.install the auxiliaryfuel tank (refer to 737 AMM 53-23-1). G. installthe enginefire extinguisherbottles removed in Step D(refer to 737 AMM 26-21-11).

Jun 30/94 737-53A1 166 23

## BOEING SERVICE BULLETIN 737-53A1 166

H. Install the wing-to-body fairing that was removed inStep A (refertoAMM 53-51-21). NOTE: The preventive modification installs new structure to replace most of the fairing support structure thatwas removed inStep A(refer to Figure 2). I. Return the airplanetoserviceable condition. Part Ill Time Umited Reoair A. Inthe wheel well, get access to the inboard side of the outer chord at BS 727. Toget the access, remove the engine fire extinguisher bottles (referto 737 AMM 26-21-11). B. Get accesstothe aft sideof thebulkhead at BS 727. To get the access,remove the cargo linerat the forward end of the cargocompartment inthe aft lower lobe. NOTE: On some airplanes there may be an auxiliary fuel tank installed. If installed, remove the auxiliary fueltank toget accesstothecargo liner (referto 737AMM 53-23-1). C. Get accessto the forward side of the bulkhead at BS 727. Remove the flap right anglegearbox 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 verticalside of the horizontal stiffenerto allow installation ofthe repair angle (referto Figure 3). E. Trim the aft part of the outboard vertical side ofthe Stringer S-18A Shear Beam to allow installation of the repair angle (refer to Figure 3). F. Drill astop crack hole at the end ofthe crack (referto737 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. Makethe repair parts (refer to Figure 4). H. Install the repair parts (refer to Figure 5).

I. Install theflap right angle gearbox and associated brackets removed inStepC (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 fireextinguisher bottles removed inStep A (referto 737 AMM 26-21-11). L. Return the airplane toserviceable condition.

Jun 30/94 737-53A1 166 

### 24

## 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 FIGURE5. INSTALL THE REPAIR

....................................... 39

Jun 30/94 737-53A1 166 25

## BOEING SERVICE BULLETIN 737-53A1166

°/ < EE DETAIL I

LEFT SIDE SHOWN RIGHT SIDE OPPOSITE (WINE-TO-BODY FAIRING NOT SHOWN)

FIGURE 1. INSPECTION Jun 30/94 SHEET 1OF 3 737-63A1 166 26

## BOEING SERVICE BULLETIN 737-53A1166

STRIN6ER 18-A STA (ON SOME AIRPLANES 727 THE OUTER CHORD OF I STRIS6ER 18-A IS 0T RIN 18- A FLAT STRAP) O 0o°

S CIEE DETAIL I



# 00 So o

Ju 3/4 HETOF 77531A6 F7 27 INBID0 P---

- 

### DETAIL I 

### ) O 0 STRIH6ER 18-A--- TYPICAL O O 0 CRACK /



# o o

a 

## DETAIL II

FIGURE 1. INSPECTION
Jun 30/94 SHEET 2 OF 3 737-53A1166

## BOEING SERVICE BULLETIN 737-53A1166

The step number shown below agree with the numbers shown insidethe circlesymbols inthefigure.

STEP TASK NAME PROCEDURE REFERENCES NOTES 1 Examine Outboard chord High Frequency NDT Part 6, 51-00-00, Examine theoutboard of Stringer 18-A Eddy Current Figure 4 surface oftheoutboard Inspection chord around the fastener head. Look for 

### cracks. 2 Examine Outboard chord Close Visual Examine the edge ofthe of frame Inspection forward flange of the outboard chord. Look for I__

_ _ _ _ _ _ _ _ _ _ _ _ cracks. 3 Examine Outboard chord Pulse Echo NDT Part 4, 53-10-01 Examine the area under offrame Shear Wave theoutboard chord of Inspection Stringer 18-A. Look for -_ - cracks. Ifthere isno indication of a crack, goto Step 4.

STEP TASK NAME PART NUMBER QTY NOTES

4 Remove / Lockbolt BACB30GW8() 2 Measure the grip length of the Discard Collar BACC3OK8 2 fastenerthatwas 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 theforward Inspection flange ofthe outboard chord. Look for cracks Ifyou do not installthe preventive modification, goto Step 6. STEP TASK NAME PART NUMBER CTY NOTES

6 Examine Hole 2 Look for damage. Drill Oversize 2 Ifnecessary,drill oversize hole hole to remove damage. Make sure that the edge margin isnot lessthan 1.5D Install Hi-Lok BACB30MB8A() (a) 2 Use the same grip length asthe or fastener thatwas removed in Step 4. BACB30MC8A() (b) 2 or BACB30MD8A() (c) 2 or equivalent. (a) Standard size. (b) 1/64 oversize. (c) 1/32 oversize.

FIGURE 1. INSPECTION Jun 30/94 SHEET3OF3 737-53A1 186 28

## BOEING SERVICE BULLETIN 737-53A1166

STA STA STA STA 727 7509 71672 

# 71 ASTA II l747 (737-100) Se

-i 727A (737-200)

< b0 >|B-518

5~~~-18^ i~9

5-20 

### SLEFT SIDE SHOWN RIGHT SIDE OPPOSITE (WING-TO-BODY FAIRING NOT SHOWN)

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION Jun 30/94 SHEET 1OF3 737-53A1 166 29

## BOEING SERVICE BULLETIN 737-53A1166

iS-`17 

### -i-t

+2.)
*e t

>: 

### INOD VIEW A-A

Jun304 SHEET 2OF 3 73753A1166 30

## BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agreewiththe numbers shown insidethecircle symbolsinthe figure.

STEP TASK NAME REFERENCES CITY NOTES 1 Remove / Stiffener 1 Discard 2 Remove/ Tee Chord 1 Keep thetee chordto use

_ _ _Keep

__ _ _ _ _ _ _again. 3 Remove/ Web 1 Discard 4 Remove/ Angle 1 Discard 5 Remove/ Attach Angle 1 Discard 6 Remove/ Filler 1 Keep the filler to useagain. 

### Keep 7 Remove/ Filler 2 Discard

FIGURE 2. ACCESS FOR THE PREVENTIVE MODIFICATION Jun 30/94 SHEET 3OF 3 737-53A1 166 31

## BOEING SERVICE BULLETIN 737-53A1166

SEE DETAIL II

SEE DETAII



### DETAIL I FLAP RIGHT ANGLE GEARBOX RIGHT GEAR BOX SHOWN LEFT GEARBOX SIMILAR

FIGURE 3. ACCESS FOR THE REPAIR Jun 30/94 SHEET1 OF4 737-53A1 166 32

## BOEING SERVICE BULLETIN 737-53A1166

SEE DETAIL III X 

### ~,,, ,/X

|-,--,--,--,-,- '- '- '' 'f }/// S-18A 

## ( 4 

## 1- /s-19



### SE DI ,SEE DETAIL I I 

### ~ ~ ~ ~ ~ ~ ~ ' -I I I I,--t-X

J, 

## C-


# <g S-ZO

INBD< D 

### DETAIL II LEFT SIDE SHOWN RIGHT SIDE SIMILAR

FIGURE 3. ACCESS FORTHE REPAIR Jun30/94 SHEET 2 OF4 737-53A1 166 33

## BOEING SERVICE BULLETIN 737-53A1166

D ;I 

## an/ A190 >S-18A 

# -191

--------------- ~ 

### ------ '----'II-

STA 727 

## -r VIEW B-B

VIEW A-A

FIGURE 3. ACCESS FOR THE REPAIR Jun 30/94 SHEET3OF4 737-63A1166 

### 34

## BOEING SERVICE BULLETIN 737-53A1166

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

STEP TASK NAME PART NUMBER Qy NOTES 1 Remove/ Flap RightAngle 1 Keep theparts to useagain. Keep Gearbox Refer toAMM 27-51-261. 2 Remove/ Tee 65-48692-5 Left Side 1 Keep the tee to use again. Keep 65-48692-12 Right Side 3 Remove/ Bracket 69-39436-2 Left Side Keep the bracket to use again. Keep 69-39437-2 Right Side 4 Trim Shear Beam Web 65-46877-() 1 Trim the aft part of theoutboard vertical sideof theShear Beam Web to allow forthe installation ofthe Repair Angle. Apply Chemical Film Apply to cut area. Refer to 737 Treatment Structural Repair Manual (Alodine) 51-10-2 Apply Primer BMS 10-11, Type 1 Apply one layertocut area 5 Trim Horizontal 65-46547-() 1 Trim theoutboard part of the Stiffener vertical side ofthe Horizontal Stiffener to allow forthe installation ofthe RepairAngle. Apply Chemical Film Applyto cut area. Referto 737 Treatment Structural Repair Manual (Alodine) 51-10-2 Apply Primer BMS 10-11, Type 1 Apply onelayertocut area.

FIGURE 3. ACCESS FOR THE REPAIR Jun 30/94 SHEET4 OF 4 737-53A1 166 35

## BOEING SERVICE BULLETIN 737-53A1166

A]

,-, 

### 1 11



# 0

VIEW A-A Aj

FIGURE 4. MAKE THE REPAIR PARTS 

# 0
Jun 30/94 SHEET 1OF3 737-S3A1 166 36

## BOEING SERVICE BULLETIN 737-53A1166 

# S

I 

### 05



## *

r 

# 0 FIGURE 4. MAKE THE REPAIR PARTS Jun 30/94 SHEET 2OF3 737-53A1 166 37

## BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown belowagree with the numbers shown inthecircle symbols inthefigure. NOTE: Make the repairparts shown inthe tablethat 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 OTY NOTES 1 Make Repair Angle AND1 0134-2008 x 20.8 1 7075-T6, or equivalent. 2 Make Shim 1.25 x 4.25 x0.032 inch thick 1 7075-T6 Aluminum Alloy Sheet. 3 Make RepairStrap 1.25 x 6x 0.18 inchthick 1 7075-T6 Aluminum Alloy Sheet. 4 Make Filler 1.4x 8.2 x0.18 inch thick 1 7075-T6 Aluminum AlloySheet. 5 Make Filler 1.2x 1.4 x0.82 inch thick 1 7075-T6 Aluminum AlloySheet 6 Make RepairAngle 4x8.2 x 0.15 inch thick 1 Referto 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 degreesto match the Repair Angle made in Step 

### 1

. Bend Vertical Wall Also, bend the verticalwall so itwillalign with the filler made inStep 4 and the Repair Angle made inStep 

### 1. HeatTreat Repair Angle Heat treatto T-6. 7 Make Shim 2.1 x 11.4 x 0.18 inch thick 1 7075-T6 Aluminum Alloy Sheet. 8 Make Shim 1.2x8.7x0.18inchthick 1 7075-T6 Aluminum Alloy Sheet.

FIGURE 4. MAKE THE REPAIR PARTS Jun 30/94 SHEET 3 OF3 737-53A1 166 

### 38

### BOEING SERVICE BULLETIN 737-53A1166

IW I~



### DETAIL I FLAP RIGHT ANGLE GEARBOX RIGHT GEAR BOX SHOWN LEFT GEARBOX SIMILAR

IFIGURE 5. INSTALL THE REPAIR Jun 30/94 SHEET 1OF 6 737-53A1 166 

### 39

## BOEING SERVICE BULLETIN 737-53A1166

/ (t (a i~ w lL 90



### SS-20A

INBD C 

### DETAIL II LEFT SIDE SHOWN RIGHT SIDE SIMILAR

FIGURE 5. INSTALLTHE REPAIR Jun 30/94 SHEET 2OF 5 737-63A1 166 

### 40

## BOEING SERVICE BULLETIN 737-53A1166

STA 727

I -_-1

. I I

__

X I a r I 

### 12rt3 --------------------------

FWD 

## VIEW A-A - 

### 1

FIGURE 6. INSTALL THE REPAIR Jun 30/94 SHEET 3 OF6 737-53A1166 41

## BOEING SERVICE BULLETIN 737-53A1166

STA 727

S-19-



# -S-20

<>FWD VIEW B-B LOOKING OUTBOARD

FIGURE5. INSTALLTHE REPAIR Jun 30/94 SHEET4OF 5 737-53A1 186 42

## BOEING SERVICE BULLETIN 737-53A1166

The step numbers shown below agree with the numbers shown inthecircle symbols inthe figure.

STEP TASK NAME PART NUMBER TY NOTES 1 Install Repair parts Temporarily install repair parts. Drill Fastener holes Remove Repair parts Deburr Fastener holes Remove sharp edges. Apply Chemical film Referto 737 Structural Repair treatment (Alodine) Manual 51-1 0-2. Apply Primer BMS 1 0-11, Type 1 2 Install RepairAngle (referto Figure 4, Step 1) 1 Installparts with BMS 5-95 fay 

### Isurface sealant. Refer to 737 3 Install Shim (referto Figure 4,Step 2) 1 Structural Repair Manual 

### 51-20-4. 4 Install Repair Strap (referto Figure 4,Step 3) 1 Install with BACB30 MB 5 Install Filler (refer to Figure 4, Step 4) 1 fasteners the same size as

- was removed. Ifnecessary, 6 Install Filler (refer to Figure 4, Step 5) use oversizefasteners. 

### Frnwfastener locations, use 7 install Repair Angle (refer to Figure 4,Step 6) 1 BACB30MB8-( )fasteners. 8 Install Shim (referto Figure4, Step 7 1 Installfastenerswet with BMS 

### 5-95 sealant. 9 Install Shim (referto Figure 4, Step 8) 1 1

0 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 Installthe tee removed in Step 65-48692-12 Right Side 2 of Figure 3. 12 Install Flap Right Angle 1 Installthe Flap Right Angle Gearbox Gearbox removed inStep 1of Figure 3. 

## Refer toAMM 27-51-261.

FIGURE 5. INSTALL THE REPAIR Jun 30/94 SHEET 5OF 5 737-53A1 168 

### 4:3

## BOEING SERVICE BULLETIN 737-53A1166

ADDENDUM FLIGHT SAFETY SECTION INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME Astructural reassessment of the 737 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56 inaccordancewith Federal Aviation Regulation (FAR) 25.571, as amended in1978, to ensure safe operation of 737airplanesthroughout their operational life. Table Iprovides asummary ofthe inspectionsspecified inAccomplishment Instructions, Part I
- Flight Safety Inspection Program and the Compliance Section. that are recommended for thedetection of cracks prior to their reaching critical lengths. Failure to detect cracks prior to their reaching critical length may result in failure ofthe outboard chord oftheframe at BS 727. Any cracked structure should be replaced priorto further flight unlessspecificallyapproved byyour cognizant regulatory agency. Please report any discrepancies to Boeing Customer Support Engineering using the reporting system described inthe addendum.

Jun 30/94 ADDENDUM Page 1of6

## BOEING SERVICE BULLETIN 737-53A1166

TABLE I
- CHORD INSPECTION Inspection Airplane Condition Inspection Threshold Repeat Inspection (See 737 Non (Flight Cycles) Interval (Flight Cycles) Destructive Test until Preventive Manual) Modification is installed Close visual inspection Service Bulletin of the theoutboard Modification not chord ofthe frame at accomplished. 27,000to 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 50,000to 60,000(b) 7,500 

### (0 Wave inspection of the or outboard chord ofthe frame at BS 727. Service Bulletin Examine area where Modification not 60,000to 70,000 (c) 5,000 (g) 

### Stringer 18A is accomplished. attached. Lower part offrame replaced per Service High Frequency Eddy Bulletin 737-53-1088. 70,000 (d) 3,000 Current inspection of the outboard chord of Service Bulletin 30,000 (after the Use the intervals shown the frame at BS 727. Modification not chord was replaced). abovefor flightcycles 

### Examine twofastener accomplished, after thechord was holes (i) *f. Upper part offrame replaced. 

### High Fequenc Eddy replaced per Servicerelcd Current inspection of ulletin 737-53-1088. the outboard surface of Stringer 18-A. Examine around the headsof twofastener holes.
Closevisual inspection Service Bulletin Next scheduled Use your Maintenance ofthethe outboard Modification structural inspection. Program Interval for chord ofthe frame at accomplished. Refertothe 737 scheduled structural BS 727. Examine the Maintenance Planning inspections. edge ofthe forward Data Manual Refertothe 737 flange. (h) D6-17594-2, Section Maintenance Planning 6-02. Data Manual D6-17594-2, Section 

### 65-02.

Jun 30/94 ADDENDUM Page2 of6

## BOEING SERVICE BULLETIN 737-53A1 166
(a) For airplanes at thisthreshold, do theinspection initiallywithin 4.500 flights after you getthis bulletin. (b) For airplanes at this threshold,do the inspection initiallywithin 2,500flights after you getthis bulletin. (c) For airplanes at thisthreshold, do the inspection initiallywithin 1,500 flights afteryou 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 airplanecollects more than 50,000flights. (f) Usethese intervals until theairplane collects more than 60,000flights. 

### (g)Use these intervals until the airplane collects more than 70,000flights. (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 8S 727 from inside the wheelwell. (i) Airplanes with 60,000to 70,000 cycles can omit this step only at the initial inspection at 1500flights after you get this bulletin. 

### 0) Airplanes with more than 70,000 cyclescan omit this step only at the initial inspection at 500 flights after you get thisbulletin.

Jun 30/94 ADDENDUM Page3 of 6

## BOEING SERVICE BULLETIN 737-53A1166
Boeing requeststhat operators use the following Structural Significant Item (SSI) Reporting System toreport any discrepanciesthat are found inaccomplishing a Flight Safety Inspection. 1. Upon recognition of discrepancy,the following information should betelegraphed 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 ofdamage including direction and size

-When discovered and inspection method used Send telegram through Boeing Field Service Representative ordirectly to: 737 Customer Support Engineering 2. An Operators Follow-Up Report containing all available pertinent data, relative to the structural discrepancy, shall be sentto Boeing. A summary ofthe information that should be reported is shown in the DISCREPANT STRUCTURE REPORT form attached. Operators may usethis form or anysutable alternativewhich containsthe same information. 3. Alldata and reportsdealingwith the Flight Safety Inspection Program shall be submitted eitherthrough a Boeing Field Service Representative or directlyto: The Boeing Commercial Airplane Group P.O. Box 3707 Seattle,Washington 98124-2207, USA Attn: 707/7271737 Service Engineering Director Org. M-7201 Mail Stop2H-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 tooperators and appropriate AirworthinessAuthorities.

Jun 30/94 ADDENDUM Page 4 of 6

## BOEING SERVICE BULLETIN 737-53A1166

DISCREPANT STRUCTURE REPORT SIDE I I REPORT DATA ATA. iNDEX REPORTINO. AIRUNE/AGENCY_

- STATION MONTH DAY YEAR
- 2 AIRCRAFT DATA MODEL SERIES TAIL NO. MFG. SERIAL NO. FLIGHT HOURS FLIGHTCYCLES 3 COMPONENT DATA (AS APPLICABLE AND AVAILABLE): NAME

. . . . . . P/N

__ _ SIN IPC/DWG. REF. SRM REF. COMPLETE THE FOLLOWING IFKNOWN 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): S8 AD IPC SRM MPD OTHER (E.G. SDR. MRR) RSIIA STRUCTURAL SIGNIFICANT ITEM NO. SERIES 50 NO. 5 SERVICE BULLETINS INCORPORATED INAREA OF DISCREPANCY SERVICE BULLETIN APPLICABLE SECTION DATE OF TOTAL FLIGHT HOURSAND NO. OF SERVICE BULLETIN INCORPORATION CYCLESAT INCORPORATION HOURS FLIGHTS HOURS FLIGHTS HOURS

- FLIGHTS 6 INSPECTION DATA (COMPLETE KNOWN INFO., CHECKAPPROPRLATE ITEMS FOR DISCREPANT STRUCTURE): CURRENT INSPECTION INTERVALS (FLIGHTS) CORRESPONDING INSPECTION LEVELS 6A WHEN DISCOVERED 68 INSPECTION LEVEL 6C DETECTION METHOD
0 SCHEOULEOMAINTENANCE 

## [I WALK-AROUND [ VISUAL 0 TAPTEST 

### [ OVERHAUL | GENERAL VISUAL [ MAG. ViSUAL SOUND j UNSCHEDULED ] EXTERNALSURVEIUANCE [DYE PENETRANT SMELL 0 SPECIALIDIRECTED (AD 58...) INTERNALSURVEILLANCE 

### [ ULTRASONIC FEEL SYMPTOM (FUEL/PRESS LEAK..) DETAILED 

### [ LOW X-RAY 0 RELATED FLEET EXPERIENCE SPECIAL FREQUENCY PRESS. LOSS 0 ACCIDENT INVESTIGATION EDDY CURRENT SSID 0 0 HIGH 0SERIES 60 FREQUENCY 

## [] SERES 50EDDY CURRENT 0BORESOOPE SMAGNETI

PARTICLE

Jun 30/94 ADDENDUM Page 5 of 6

## BOEING SERVICE BULLETIN 737-53A1166

DISCREPANT STRUCTURE REPORT 

## I SIDE 2 7 DISCREPANCY DESCRIPTION:

AttAch sketch, photos and text as required to desicobedefect and specificlocation. When apIicablegivedetail. oiassociated disaepanceson the samre aeaft. reLated expenence wnth this discrepancy onany aircraft, and previous modifcation (s) to the d'sepant sfludure. 7A TYPEOF DISCREPANCY: |]BENT []CONTAMINATEO 

### nDENTED []LOOSE []WRINKLED

BROKEN (]CORRODED [J DETACHED MISSING 

### [ BUCKLED []CRACKED 

## I] IMPROPERLY OUTOF-TOUERANCE 

## U BURNED []DEFORMED ADJUSTED STUCK I] 

### [i CLOGGED 

## [J DELAMINATED LEAK [WORN

__ - 78 SIE OF DISCREPANCY: 

## D INCHES. OR 

### [ CENTIMETERS AREA X DEPTH

- CRACK LENGTH INITtALLY DETECTED D DATE

- FINAL MEASUREMENT (IF DIFFERENT) DATE 7C DISCREPANT PART: 

### [ FRAME/BUUKHEAD 0 SKIN ] JOINT/SPLICE [J PRESSURE BULKHEAD i PLATE/PANEL 

### I] LUG 

### O FRAMEAROUNDOPENING ] CHORD [ WELD

WINDOW FORGING ]STRINGER NO. BOND KEELBEAM fiBEAM OPENHOLE ] FLOOR STRUT/BRACE ] FASTENER HOLE ] WING CENTER SECTION [UNK/ROD 1 CUT-OUT

WIG DRY-BAY AREACOMPT. LONGERON ACCESS/LIGHTENING HOLE [ SPAR 0 FITTING NOTCHAGROOVE 

### [ RIB 

### I] BRACKETICUP j DISCONTINUITY 

### O LANDING GEAR BEAM [j STOP

- ] BASIC MATERIAL ] FLAP TRACK [j FASTENER BUSHING

F PAIRING [ PIN 

### O O__
_ _ _ I]_
_ _ _ __ _ _ _ 7D LOCATION OF DISCREPANT PART: GENERAL LOCATION (E.G.. BILGE. UNDER GALLEY) 

## n BODY STA. NO. DOR/ACCESS PANEL INTERIOR 

### ] EXTERIOR 

# o WING STA NO- RUDDER INBOARD OUTBOARD [ VERT. STAB. STA[ ELEVATOR ULEFT RIGHT [] HOR12STAB.STA [ AILERON FORWARD ] AFT f] NACELLE/PYLON FLAP UPPER L LOWER COMPARTMENT

_ _ SLAT LEADING EDGE TRAILING EDGE 

# DNOSE
LANDING GEAR SPOILER MIDDLE 

### [ SIDE MAIN LANDING GEAR TAB (ALSO CHECKASOVE) SPECIFIC LOCATION WING LANDING GEAR BODY LANDING GEAR j

INSPECTIED BY | E~RED BY ORIGWATEO BYDAI



### Jun 30/94 ADDENDUM Page6 of 6

# D n
- M

- O Commercial 

# 737 Airplane Group 

# Service Bulletin
Number 737-53A1168 

## Date: June 30, 

## 199 

## Evaluation Form ATA System: 5311 Prepared By: Maurice Chatwin

SUBJECT: FUSELAGE

- FRAMES

-BODY STATION 727OUTBOARD CHORD AT STRINGER 1 8A, INSPECTION AND PREVENTIVE MODIFICATION Use thisevaluation form totell us what you think of the qualityof this service bulletin. We will use the data that you give us to improve the qualityof our service bulletins. Please include data about these or other items:

- Did this service bulletin meetyour estimate of quality?

- How easy isthis service bulletin to understand?

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

- Will you do thisservice bulletinfully? Ifnot, pleasetell uswhy.

- Is the Manpower estimate satisfactory? NOTE: Pleasedo not use this evaluation form to tellus to make changesto your manuals. To make these changes, pleaseuse a Publication Change Request (PCR) form. Please give usthisdata: OPERATOR: TODAY'S DATE: PREPARED BY: TITLE: ORGANIZATION: TELEX CODE: TELEPHONE NUMBER: 

### COMMENTS:

Ifyou have other comments please use the other side. Thank you for the time you used to complete this form. Givethecompleted evaluation form to your Boeing Field Service Representativeor send the evaluation form directlytothis address: T.J.Taylor, Manager Service Bulletin Engineering Boeing Commercial Airplane Group 

### P.O. Box3707, Mail Stop2L-02 Seattle, WA 98124-2207

BOEING GOMMERCIALAIRPLANE GROUP P.O. BOX 3707 SEATTLE WASHINGTON 98124-2207 

### Page 1 of

### I