This sheet transmits REVISION 3 dated November 30, 1989

of Service Bulletin 727-53A0124, "FUSELAGE - MAIN WHEEL WELL PRESSURE FLOOR

INSPECTION, MODIFICATION AND REPAIR".

NOTE: This revision constitutes a complete reissue.

SUMMARY

This revision is issued to recommend the modification per this service

bulletin for incorporation on aging 727 airplanes. Also provided is an

additional modification kit to install a 0.100 inch thick doubler between

Body Station (BS) 910 and BS 930 and between Buttock Line (BL) 0 and right

BL 10. The incorporation threshold for this service bulletin is shown in

the Description and Accomplishment Instructions.

As a result of the FAA-sponsored Aging Fleet Conference, a 727 Structures

Working Group with Airline and Boeing members and FAA observers was formed

to review structural service bulletin modifications and recommend selected

bulletins for incorporation on aging airplanes. Based on a structural

review of the 727 airplane, the Structures Working Group has determined that modification per this service bulletin, at or before the indicated

threshold, should be accomplished to support the continued structural

integrity of aging 727 airplanes.

Airplane effectivity is expanded, to include all 727 airplanes, and updated to reflect current airplane ownership.

Airplanes modified per previous releases of this service bulletin require inspection until modified to add the additional doubler between BS 910 and

BS 930 and between BL 0 and right BL 10.

The original issue of this bulletin was issued, as an Alert Service

Bulletin, therefore the "A", is added to the bulletin number.

This service bulletin is rewritten to comply with current service bulletin format and therefore revision bars have been omitted because of the

extensive rewrite.

REVISION HISTORY

Original Issue: May 3, 1974

Revision 1: September 27, 1974

Revision 2: May 2, 1975

Revision 3: November 30, 1989
ACTION (PRR 23792)

Based on a structural review of the

727 airplane, incorporation of the

modification per this service bulletin

is recommended on aging airplanes.

Three operators reported cracks from

25 to 48 inches long in the Main

Landing Gear (MLG) wheel well pressure

floor, resulting in rapid

depressurization. Twenty four

operators reported 67 airplanes with

cracks up to two inches long located

in the reinforcing beads between Body

Station (BS) 910 and BS 940 on both

sides of the airplane between Buttock

Line (BL) 10 and BL 50. The airplanes

had accumulated between 12,600 and

43,300 flight cycles and 18,000 and

51,600 flight hours.

Since Revision 2 five operators

reported five airplanes with cracks

out of the area covered by the

modification of the service bulletin.

The cracks were located in the

reinforcing beads between BS 910 and

BS 930 and between BL 0 and right BL

10. The airplanes had accumulated

between 18,200 and 42,100 flight

cycles and 21,300 and 39,900 flight

hours.

Continued operation with undetected

cracks could result in loss of cabin

pressure. The cracks have been

attributed to fatigue.

This service bulletin is the subject

of Federal Aviation Administration

(FAA) Airworthiness Directive

77-13-15, Amendment 39-2944.

As recommended by the 727 Aging Fleet

Structures Working Group, accomplish

modification per the Accomplishment

Instructions at or before the

accumulation of 60,000 flight cycles.

Inspect pressure floor reinforcing

beads adjacent to BS 910 floor beam of

airplanes that have accumulated 15,000

flights at maintenance intervals as

described in the Description and

Accomplishment Instructions until

accomplishing preventive modification

or repair per this service bulletin.

Group 2 and 3 airplanes and airplanes

previously modified require inspection

of unmodified areas at 2000 flight

cycles intervals until accomplishing

preventive modification or repair per

this service bulletin.

If cracks are found within specified

limits, accomplish repair per this

service bulletin. If cracks exceed

specified limits, contact Boeing.

If no cracks are found, accomplish the

preventive modification per this

service bulletin or repeat inspection

at specified intervals until

accomplishing preventive modification

or repair per this service bulletin.

EFFECTIVITY

All 727 airplanes in three groups.

Group 1 - Line numbers 1 through 1102.

Group 2 - Line numbers 1103 through

1477.

Group 3 - Line numbers 1478 through

1832.

Summary Page 1 of 2

BACKGROUND
DETAIL I

(PLAN VIEW)

May 3/74

REV. 3: Nov 30/89 Summary Page 2 of 2
SUBJECT: FUSELAGE - MAIN WHEEL WELL PRESSURE FLOOR INSPECTION,

MODIFICATION AND REPAIR

I. PLANNING INFORMATION

A. Effectivity

1. Airplanes Affected

See Service Bulletin Index Part 3 for cross reference of Variable

Number to Airplane Serial Number.

This change is applicable to airplanes listed below in accordance

with PRR 23792.

LISTING BY CUSTOMER CODE AND VARIABLE NUMBER

CODE GROUP VARIABLE NUMBER

1 E0301-E0303

E0332

E0348-E0349

QA101-QA141

2 QA142-QA187

3 QA188-QA199

E0305-E0309

E0334

E3075

QA854

E0311-E0326

E0336-E0339

E3519-E3520

QA856-QA869

E0328-E0330

E0345

QA014

QB801-QB810

E3032-E3033 E3062

E3148

E3286-E3289

E3651

1 QD205

2 QD206-QD212

3 QD218-QD239

QD215-QD217

1 QA351-QA352 QA551-QA556

3 QD761-QD769 QD781-QD782

QA559-QA570

May 3/74

REV. 3: Nov 30/89

7 27 -53A0124

Page 1 of 35

AAL

AAT

ACE

1 E3029

1 E0130

ACN

AFA
VARIABLE NUMBER (CONTINUED)

1 E5410

1 QA574-QA576

2 QB451-QB453

3 QB454-QB458

1 E3681

1 E0104

E3145

1 QA040

2 QA044-QA046

1 E0133

1 E0119

3 QD040

2 QD601-QD603

3 QD450

QD034

QD043-QD046

QD604-QD607

1 E3401

QA902

2 QA378

QD931-QD932

3 QB619

QD555

E3521 E5058

QA905-QA906

QA894-QA895 QD902

QD951-QD952

QB622 QB624

QD558 QD909

E5142

QD904-QD905

QB626-QB628

QD953-QD954

1 QD001-QD004

2 QD007-QD009

3 QD010-QD012

2 QD191-QD192

3 QD518

1 E3036

E3221-E3224

E5451

2 QD553-QD554

3 QD581-QD583

1 E0034-E0036

E3246

QA039

3 QD474-QD475

E3068

E3402

E5453

E3141-E3143

E3406

QA572

QD991-QD992

E3024

E3248

QA041-QA043

E3072

E3511

QA853

1 E3038

May 3/74

REV. 3: Nov 30/89

727-53A0124

2

AFG E5424

ALG

AMA

AMJ

ANA

ANC

E0310

E3341

E0342

E5161

E3028

E5403

ANS

ARG

ASA

AUS

AVG

AVI

AVN

AVO

E3204

E3412

QB031

E3244

QA036

QD121

CODE GROUP
VARIABLE NUMBER (CONTINUED)

E3654 E5225 E5405

QD451

QB032-QB033

E3005

E5351-E5352

QD031-QD032

QA897-QA899 QB601-QB615

QB616-QB617

1 E3509

1 E3065

1 E3506

1 E0038-E0042

E3241

E5201

QA308-QA314

2 QA341-QA344

3 QA345-QA349

3 QB625

1 E0304

1 QB034

2 QB041-QB046

3 QB047-QB049

1 E3202

E5032

2 QD410

1 E3071

1 QA073-QA079

QA909-QA917

2 QA098-QA099

3 QA939-QA946

1 E3146

QD005

2 QD903

E5112

E3512

E0202

E3245

E5455

QA325-QA340

QA890-QA893

QB901-QB904

E5050

QB036-QB040

QD444

QB051-QB058

E3409

E5042-E5043

E3344-E3345

QA081-QA092

QA919-QA926

QA949

E3149

QD033

QL004-QL005

E5141

E5409

E0205

E3247

QA019-QA021

QA896

E5481-E5483

E5435

E3001

E3253

QA301-QA306

QD085-QD088

QB060-QB064 QD571-QD572

E3411 E3415-E3418

E5045

E3781-E3783

QA096-QA097 QA907

QA929-QA933 QB501-QB552

QB553-QB575

QB035 QB114

QD123

QL031-QL032

May 3/74

REV. 3: Nov 30/89

727-53A0124

3

CODE

AVT

BHR

BHT

BLA

BLG

BNF

GROUP

1

3

1

1

1

1

2

3

BNR

BRS

CAF

CAL

CAY

CKF

CMA

CMI

CMR

CRU

DAL

DAN
VARIABLE NUMBER (CONTINUED)

1 E0030

E5274

E0124

E5382

1 QB105QB110 QB115-QB119 QB115 

2 QB310-QB316 QB351-QB352

E3622

E5402

E5046-E5047

QB301-QB309

1 E0351

1 E3206

1 E3755

2 QD351

E5404

1 E3014

3 QB065 QD452

1 QA601-QA605

QA627-QA643

2 QA644-QA658

3 QA659-QA684

1 E5418

3 QD908

3 QD661-QD663

1 QA573

QA607-QA620 QA622

QA686-QA688

QA855

1 E3101

E5104-E5105

E5281

1 E0201

1 E5353

1 E3704

1 QA901

E3151-E3152

E5108

E5426

E3275-E3276 E3652

E5273 E5277

E5241

QA904

1 E0120

E0134-E0138

E3277

E5052-E5054

E5101-E5102

E5242

QD035-QD036

2 QD037-QD039

3 QD041-QD042

E0122-E0123

E3257-E3261

E3283

E5056-E5057

E5163-E5164

E5408

QD201-QD204

QD213-QD214

QL501-QL515

E0125-E0129

E3266-E3267

E3290

E5059-E5063

E5221-E5224

E5420

E0131-E0132

E3273-E3274

E5048-E5049

E5067

E5226-E5240

E5454

May 3/74

REV. 3: Nov 30/89

727-53A0124

4

DHL

DLH

DNV

DOC

DOM

DON

EAD

EAL

EKO

ESM

ETH

EUR

QA624

EVR

FAA

FAM

FBT

FCT

FED

CODE GROUP
CODE GROUP VARIABLE NUMBER (CONTINUED)

FMR 1 E3346

FRB 1 E3655

FTL 1 E0331 E0333 E0335

E0343-E0344 E0346-E0347 E3070

E3076 E3577

FUN 1 E3419

GEO 1 E0216

GLE 1 E3144

GRP 1 E0101

GTR 1 E3701-E3703 QA038 QA908

HAP 1 E3114 E3452

3 QD971-QD972

HAV 1 E3026 E3116

HEM 1 E3077

HTV 1 E3176

IAL 1 QA002 QA359

IBE 1 QB121-QB145 QB147-QB149

2 QB151-QB153

3 QB155-QB158

ICC 1 E3064 E3069

ICE 1 E5417 QD006

3 QD791

INI 1 E3150

IRN 1 E0204 E3118 E3472-E

2 QD104-QD105

IRQ 2 QD421-QD423

3 QD424-QD426

JAM 2 QD281-QD284

JAT 1 QD142-QD143

2 QD144-QD145

3 QD146-QD149

May 3/74

REV. 3: Nov 30/89

E0340-E0341

E3073-E3074

QA918

E3473 QD101-QD103

727-53A0124

5
CODE

JPA

JTA

JTE

KAB

KAL

KBA

KEL

KEY

KLA

KUW

LAA

LAB

LAC

LDE

LIL

LNA

MAA

MEZ

MGM

MME

MXA

MXG

May 3/74

REV. 3: Nov 30/89

GROUP VARIABLE NUMBER (CONTINUED)

1 E0206

1 E0213 E3407

1 E0418 E0420-E0422 E3117

E3205 E3347-E3348 E3350

1 E0103 E0107

1 QA015 QA022 QA024-

QA037

1 E3574

1 E5001 E5428

1 E0029 E0033 E3027

E3250-E3252 E3571

1 E3604

3 QD801-QD804

1 QA316

2 QA317-QA324 QB651

1 E3102 E3522 E5421

2 QD161-QD163

3 QD701-QD702 QD907

1 E0032 E3103 E3517

E5051 E5115

3 QD973

2 QD446

1 E3030

1 E0211

2 QD906

1 E3504-E3505 E3510

1 E0209

1 E3171-E3172 E3174-E3175 E3553

1 E3035 E3037

E3201

QA025 QA033-QA035

E3243

E3573

727-53A0124

6
VARIABLE NUMBER (CONTINUED)

1 E5501

3 QL081

1 E3242

1 QA557-QA558

1 E5279

1 E3021-E3023

E3039-E3040

QA708-QA720

2 QA725-QA745

3 QA746-QA753

E3025 E3031 E3034

E3173 QA701-QA703 QA705-QA706

QA722-QA723

QD441-QD443 QD445 QD447

QD448-QD449 QD453 QD711-QD717

1 E3004

1 QA001 QA801-QA805

1 E0210

E5002

E5036-E5037

E5280

E5423

1 QA003

QA216-QA225

QA707

QB101-QB104

3 QD691-QD692

QA057-QA058

QA366

QA721

QA201-QA207

QA369-QA371

QA851-QA852

QA209-QA214

QA704

QB01-QB002

QD821-QD828

1 E3203

1 E3115

1 E3507

1 E3503

1 QA059-QA072

2 QA878-QA889

3 QD512-QD517

QD401

E3621 E5278

QA870-QA877

QD501-QD510

1 QA005-QA009

QA358

2 QA372-QA373

3 QA374-QA376

QA023

QA360-QA365

QA928

QA026-QA032 QA051-QA056

QA367-QA368

May 3/74

REV. 3: Nov 30/89

727-53A0124

7

NAU

NGA

NMB

NOB

NOM

NWA

OCP

OLY

OMA

ORI 1 E3003

E5031

E5044

E5411

E5004

E5039

E5381

E5433

E5006

E5041

E5401

E5502

PAA

PAF

PAN

PCT

PER

PEX

PIE

CODE GROUP
UP VARIABLE NUMBER (CONTINUED)

1 E0413

2 QD403

1 QA577-QA579

2 QA581-QA584

3 QA585

1 E0212

3 QD407

3 QE002

1 E3285

3 QD124-QD126

1 E3784 E5419

1 E3420

1 E5065 E5068

1 E5035 E5040

1 E5003 E5005 E50

E5415

1 E0414 E3576

1 E3113

1 E0208 E3451

1 E3684

3 QB629

2 QD402

1 E0207

1 E3421

1 QL001-QL003

3 QD164 QD427 QD6

2 QD471-QD473

1 E3513 E3516 E36

3 QD741

07-E5011 E5413

84-QD685 QL006-QL008

82

May 3/74

REV. 3: Nov 30/89

727-53A0124

8

CODE GRO

PJE

QAT

RAM

RBA

RBH

RGI

RJA

RNA

RNF

RNZ

RVV

RYN

SAE

SAH

SAK

SAN

SCA

SEN

SIG

SKL

STR

SYR

TAM
VARIABLE NUMBER (CONTINUED)

1 QA093-QA095 QD302

3 QD303-QD304

1 E3013 E3501

1 QD321-QD322 QD324

2 QD325 QD511

3 QD327-QD330

1 E3410

1 E5114

1 E3011-E3012 E3508

1 E3002

1 E3284

3 QD910

1 E0106

E3342-E3343

QA353-QA355

QA625-QA626

E0116

E3349

QA357

E0121

QA010-QA012

QA606

E0140

QA017-QA018

QA623

1 QA571

2 QB402-QB407

1 E0401-E0402

E0416-E0417

QA529-QA537

2 QB204-QB210

3 QB211-QB220

E0404-E0408 E0410

E0419 E0423

QB201-QB203

E0412

QA501-QA527

1 E0001

E3262-E3265

2 QA429-QA474

3 QA475-QA499

E0003 E0005-E0028 E3254-E3256

E3268-E3272 E3278-E3282 QA401-QA428

QB701-QB705

1 E3523

1 E0203

1 E3061 E3063 E3066-E3067

1 E5033-E5034

E5113

E5251-E5252

E5422

2 QA927

3 QA936-QA938

E5038

E5116

E5271

E5427

QA934-QA935

E5106-E5107

E5162

E5275-E5276

E5429

QD551-QD552

E5109-E5111

E5243-E5245

E5301-E5306

May 3/74

REV. 3: Nov 30/89

727-53A0124

9

E3653

TAP

TBL

THY

TMI

TNN

TOS

TOU

TRD

TRI

QA004 QA903

TSI

TUN

TWA

QB401

UAL

ULL

UO5

U06

UPS

CODE GROUP
VARIABLE NUMBER (CONTINUED)

3 QB066-QB068 QB618

QD681-QD683

1 E0215

QB620-QB621 QB623

E3059

1 E3683

1 E3572 E3575

E5406-E5407 E5412

E3751-E3754 E5272

3 QD556-QD557

1 E3006

1 E0350

3 QE001

1 E3601-E3603

3 QD621-QD624 QD641

1 E0214

LISTING BY VARIABLE NUMBER

GROUP 1

E0001-E0042

E3001-E3006

E3101-E3103

E3221-E3224

E3471-E3474

E3601-E3604

E3701-E3704

E5101-E5116

E5251-E5252

E5401-E5424

E5481-E5483

QA201-QA225

QA501-QA537

QA851-QA877

QB114-QB119

QD01-QD006

QD141-QD143

QL001-QL003

E0101-E0140

E3011-E3014

E3111-E3118

E3241-E3290

E3501-E3513

E3621-E3622

E3751-E3755

E5141-E5143

E5271-E5281

E5426-E5429

E5501-E5502

QA301-QA316

QA551-QA579

QA901-QA918

QB121-QB149

QD031-QD036

QD201-QD205

E0201-E0216

E3021-E3040

E3141-E3152

E3341-E3350

E3516-E3523

E3651-E3655

E3781-E3784

E5161-E5164

E5301-E5306

E5433

QA001-QA043

QA325-QA340

QA601-QA643

QB001-QB002

QB201-QB203

QD085-QD088

QD301-QD302

E0301-E0351

E3059

E3171-E3177

E3401-E3421

E3551-E3553

E3677

E5001-E5011

E5201-E5203

E5351-E5353

E5435

QA051-QA097

QA351-QA371

QA701-QA724

QB031-QB040

QB301-QB309

QD101-QD103

QD321-QD324

E0401-E0423

E3061-E3077

E3201-E3206

E3451-E3452

E3571-E3578

E3681-E3684

E5031-E5068

E5221-E5245

E5381-E5382

E5451-E5455

QA101-QA141

QA401-QA428

QA801-QA805

QB101-QB110

QB401

QD121-QD123

QD401

May 3/74

REV. 3: Nov 30,89

727-53A0124

10

USA

USV

VAC

VAR

VSP

VTC

WEF

WST

WWC

YEM

ZAR

CODE GROUP
LISTING BY VARIABLE NUMBER (CONTINUED)

GROUP 2

QA044-QA046

QA372-QA373

QA725-QA745

QB204-QB210

QB501-QB552

QD104-QD105

QD281-QD284

QD421-QD423

QD601-QD603

QL031-QL032

QA098-QA099

QA378

QA878-QA899

QB310-QB316

QB601-QB615

QD144-QD145

QD325-QD326

QD441-QD447

QD901-QD906

QA142-QA187

QA429-QA474

QA919-QA935

QB351-QB352

QB651

QD161-QD163

QD351

QD471-QD473

QD931-QD932

QA317-QA324

QA581-QA584

QB041-QB046

QB402-QB407

QD007-QD009

QD191-QD192

QD402-QD403

QD501-QD511

QD951-QD952

QA341-QA344

QA644-QA658

QB151-QB153

QB451-QB453

QD037-QD039

QD206-QD217

QD410

QD551-QD554

QL004-QL005

GROUP 3

QA188-QA199

QA659-QA688

QB051-QB068

QB616-QB629

QD040-QD046

QD303-QD305

QD474-QD475

QD604-QD607

QD691-QD692

QD781-QD782

QD953-QD954

QL081

QA345-QA349

QA746-QA753

QB154-QB158

QB701-QB705

QD124-QD127

QD327-QD330

QD512-QD518

QD621-QD624

QD701-QD702

QD791

QD971-QD973

QL501-QL515

QA374-QA376

QA936-QA946

QB211-QB220

QB801-QB810

QD146-QD149

QD407

QD555-QD558

QD641

QD711-QD717

QD801-QD804

QD991-QD992

QA475-QA499

QA949

QB454-QB458

QB901-QB904

QD164

QD424-QD427

QD571-QD572

QD661-QD663

QD741

QD821-QD828

QE001-QE002

QA585

QB047-QB049

QB553-QB575

QD010-QD012

QD218-QD239

QD448-QD453

QD581-QD583

QD681-QD685

QD761-QD769

QD907-QD910

QL006-QL008

2. Spares Affected

None

May 3/74

REV. 3: Nov 30/89

727-53A0124

11
B. Reason

As a result of the FAA-sponsored Aging Fleet Conference, a 727

Structures Working Group with Airline and Boeing members and FAA

observers was formed to review structural service bulletin

modifications and recommend selected bulletins for incorporation on

aging airplanes. This service bulletin modification has been

recommended for incorporation on aging 727 airplanes.

Incorporation of the preventive modification described in this

bulletin will reduce the possibility of cracks in the nain gear wheel

well pressure floor adjacent to the floor beams at BodY Stations (BS)

900, 910 and 920. If cracks occur and progress undetected, they could

result in rapid loss of cabin pressurization.

Three operators reported cracks from 25 to 48 inches long in the Main

Landing Gear (MLG) wheel well pressure floor, resulting in rapid

depressurization. Twenty four operators have reported 67 airplanes

with cracking in the reinforcing beads between BS 910 and BS 940 on

both sides of the airplane between Buttock Line (BL) 10 and BL 50.

The airplanes had accumulated between 12,600 and 43,300 flight cycles

and 18,000 and 51,600 flight hours.

Since Revision 2 five operators reported five airplanes with cracks

outside of the area covered by the modification of the service

bulletin. The cracks were located in the reinforcing beads between BS

910 and BS 930 and between BL 0 and right BL 10. The airplanes had

accumulated between 18,200 and 42,100 flight cycles and 21,300 and

39,900 flight hours.

Revision 1 was issued to add the installation of stiffening straps at

BS 910 to the preventive modification. Also added was a new repair

doubler that extended beyond the flanges of the floor beams.

Revision 2 was issued to add the installation of stiffening straps at

BS 910 and 920. Also added was new repair straps that install over

the doubler at each floor beam.

Revision 3 is issued to provide the recommendation of the Aging Fleet

727 Structures Working Group. Also provided is an additional

modification kit to install a 0.100 inch thick doubler between BS 910

and BS 930 and between BL 0 and right BL 10.

May 3/74 727-53A0124

REV. 3: Nov 30/89 12
C. Description

Based on a structural review of the 727 airplane, it is recommended

that the modification per Accomplishment Instructions of this service

bulletin be accomplished prior to, or upon accumulation of 60,000

flight cycles

Inspect pressure floor adjacent to Body Station (BS) 910 floor beam at

or prior to 15,000 flights and thereafter at maintenance intervals of

2000 flight cycles or less until accomplishing preventive modification

or repair per this service bulletin. Airplanes exceeding this

threshold should be inspected within 800 flight cycles after receipt

of this Revision. Group 2 and 3 airplanes and airplanes previously

modified require inspection of unmodified areas within 800 flight

cycles after receipt of this Revision and thereafter at 2000 flight

cycle intervals or less until installing the 0.100 inch thick doubler

between BS 910 and BS 930 and between Buttock Line (BL) 0 and right BL

10 per this Revision 3.

If a visual inspection is performed and evidence of cracking or flaked

paint is detected, verify cracked condition with eddy current or

penetrant inspection method.

If cracks are detected, perform similar inspection of pressure floor

adjacent to BS 900 and 920 floor beams and install repair doublers as

required prior to next flight. Alternately, If cracks do not exceed

limits specified in Table V, stop drill and seal cracks and install

repair doubler within 600 flights. Repeat inspection of unrepaired

areas at maintenance intervals of 2000 flight cycles or less until

accomplishing the preventive modification or repair per this service

bulletin.

If no cracks are found, accomplish the modification per this Revision

3 or repeat inspection at 2000 flight cycle intervals.

Group 2 and 3 airplanes had reinforcement straps installed on the

pressure floor at Stations 900, 910 and 920 during production.

Group 3 airplanes had different flap control pulley installed at

Station 918 and right Buttock Line 12.

May 3/74 727-53A0124

REV. 3: Nov 30/89 13
This service bulletin is the subject of Federal Aviation

Administration (FAA) Airworthiness Directive 77-13-15, Amendment

39-2944.

NOTE: 1. Contact Boeing for instructions if any damaged areas

exceed the specified limits. To expedite Boeing response,

be specific when defining and locating the damage.

Circumstances leading up to the damage and any secondary

effects, when known should be included in the

communication and followed up by sketches and photographs

when appropriate. In addition, where corrosion is

involved, length, width, and greatEAst depth of clean-up

are required.

CONTACT: BOEING COMMERCIAL AIRPLANES

ATTENTION: MANAGER, AIRLINE SUPPORT

2 Due to the corrosion conductive environment of the area

and since corrosion could aggravate the problem described

herein, it is suggested that the operator initiate a

program of corrosion preventive maintenance in the wheel

well, including inspection and restoration of the

protective finish and application of water displacing

corrosion inhibiting compound, with special emphasis upon

the ends of all reinforcing beads in the pressure floor.

(See Corrosion Prevention Manual, Part II, Subject

53-30-27, Figure 5).

3. This service bulletin is listed in Boeing Document

D6-54860

4. Concurrent incorporation of Service Bulletin 727-53-0149

is suggested due to similar access requirements.

May 3/74

REV. 3: Nov 30/89

727-53A0124

14
D. Approval

This service bulletin has been reviewed by the Federal Aviation

Administration (FAA) and the repairs and modifications herein comply with the applicable Federal Aviation Regulations (FAR's) and are FAA

approved.

The interim repair or deferral of repair described in Accomplishment

Instructions, has FAA approval contingent on accomplishment of the

inspections at the intervals specified in the Accomplishment

Instructions.

The FAA has determined that modification, inspection, and/or repair in

accordance with Revision 3 to Service Bulletin 727-53A0124, "FUSELAGE - MAIN WHEEL WELL PRESSURE FLOOR INSPECTION, MODIFICATION AND REPAIR"

is an acceptable alternate means of compliance for Airworthiness

Directive (AD) 77-13-15, Amendment 39-2944.

The FAA has determined that modification and/or repair in accordance

with Revision 3 to Service Bulletin 727-53A0124, "FUSELAGE - MAIN

WHEEL WELL PRESSURE FLOOR INSPECTION, MODIFICATION AND REPAIR" is an

acceptable alternate means of compliance for the modifications

specified in Boeing Document D6-54860, which is the subject of Notice

of Proposed Rule Making (NPRM) Docket Number 89-NM-60-AD.

May 3/74

REV. 3: Nov 30/89

727-53A0124

15
E. Manpower

Approximately 222 man-hours are required to accomplish this

modification per airplane .

The following breakdown of manpower requirements is suggested as a

guide to assist operators in planning and accomplishing this

modification. This estimate is for direct labor performed by an

experienced crew. It does not include setup, planning,

familiarization, cure time, part fabrication, tool acquisition, or

lost time. Factor this estimate as necessary based on your own

experience.

Operation Crew size

Inspection 2

Man-Hours

2

Elapsed

Time

(Hours)

2

Modification

Access

Installation

Restoration

Operational and

Leak Checks

TOTAL PER AIRPLANE

May 3/74

REV. 3: Nov 30/89

8

6

8

4

32

126

48

16

222

4

21

6

4

35

727-53A0124

16
F. Material - Price and Availability

1. The following kit identified in Paragraph II.A may be obtained

from Boeing within the terms and conditions defined below. The

quotation indicates the quantity and date when initial kit will

be available. When source capacity is limited and tooling or

material availability is the pacing factor, operator purchase orders will receive an allocation from the available quantities

based on receipt date of purchase order by the Spares Department

and based on operator's planned modification schedules.

Therefore, operators are requested to include planned dates of

incorporation on their purchase orders. When initial quantities

are depleted, additional kits will be available as indicated in

the Reorder Lead Time (ROLT) column. Reorder lead time is

computed from date of receipt of operator's purchase orders.

Kit Number Desc

65-89360-128 Kit

cription Date

Dec 8, 1989

ROLT

Qty Weeks Unit Price

100 22 $283.00

Date November 30. 1989

The prices quoted are subject to the terms and conditions of

Boeing's standard purchase order acknowledgement. Quotations are

subject to acceptance within 120 days from date hereon. After

expiration of the quotation, price and delivery data will be

provided upon request. Prices quoted in United States Dollars.

Terms: Net 30 days.

Address purchase orders and correspondence pertaining to this

quotation to Director of Spares, and refer to this service

bulletin number.

May 3/74

REV. 3: Nov 30/89

727-53A0124

17
2. The following kits identified in Paragraphs II.A and II.B may be

obtained from Boeing within the terms and conditions defined

below. The quotation is computed from date of receipt of

operator's purchase orders. Improved flow times may be possible

if necessary to support operator's planned modification schedule.

Therefore, operators are requested to include planned dates of

incorporation on their purchase orders.

Kit Number

65-89360-5

65-89360-6

65-89360-7

65-89360-8

65-89360-9

65-89360-10

65-89360-11

65-89360-12

65-97861-1

65-97861-2

65-97861-3

65-97861-4

65-97861-5

65-97861-6

Description

Kit

Kit

Kit

Kit

Kit

Kit

Kit

Kit

Kit

Kit

Kit

Kit-Supplemental

Kit-Supplemental

Kit

Delivery

37

37

37

37

37

37

37

37

Inactive

Inactive

Inactive

20

20

22

Unit Price

$ 358.00 $ 358.00 $ 184.00 $ 184.00 $ 288.00 $ 288.00 $ 528.00 $ 528.00

for procurement

for procurement

for procurement

$1212.00 $ 271.00

$2906.00

Date November 30. 1989

The prices quoted are subject to the terms and conditions of

Boeing's standard purchase order acknowledgement. Quotations are

subject to acceptance within 120 days from date hereon. After

expiration of the quotation, price and delivery data will be

provided upon request. Prices quoted in United States Dollars.

Terms: Net 30 days.

Address purchase orders and correspondence pertaining

quotation to Director of Spares, and refer to this

bulletin number.

to this

service

G. Tooling - Price and Availability

None

H. Weight and Balance

Applicability

65-89360-128

65-97861-6

Change in

Weight

(Pounds)

+ 3.6

+17.4

Change in

Moment

(Pound-Inches)

+ 3312

+15860

May 3/74

REV. 3: Nov 30/89

727-53A0124

18
I. References

1. Existing Data:

a. Engineering Change Memo PRR 23792

b. 727 Structural Repair Manual Subjects 51-30-02 and 51-30-05

c. Corrosion Prevention Manual, Part II, Subject 53-30-27,

Figure 5

d. Boeing Standard Overhaul Practices Manual 20-50-12

e. Boeing Service Bulletin 727-53-0149, "FUSELAGE - MAIN WHEEL

WELL PRESSURE FLOOR INSPECTION, MODIFICATION AND REPAIR"

f. FAA Airworthiness Directive 77-13-15, Amendment 39-2944

g. Boeing Document D6-54860 "Aging Airplane Service Bulletin

Structural Modification Program - Model 727"

2. Data supplied in support of this service bulletin:

a. Drawings:

Drawing No. Sheet DCN ADCN Title

65-18745 3 J 29,30 Pressure Floor

31,32 Installation Main Gear

33 Wheel Well, Sta 870-950

65-89360 2 A 1 Doubler Installation - 3 C 1 Main Gear Wheel Well

4

7

3. Process Data:

Boeing Process Specifications that are listed on drawings supplied in support of this service bulletin are not detailed in

this service bulletin since they are common practices which can

be accomplished in accordance with operator's normal procedures.

J. Publications Affected

Publication Chapter-Section

727 Structural Repair Manual .................. 53-10

May 3/74 727-53A0124

REV. 3: Nov 30/89 19
II. MATERIAL INFORMATION

A. Parts Required Per Airplane

NOTES: 1. The following kits in Table II may be obtained as noted

Paragraph I.F. or components may be fabricated,

described, or obtained from operator's inventory

industry sources, as desired.

2. The following kits and operator furnished materials listed

in Paragraph II.A.2 are required to modify each airplane.

Table II

Kit Applicability

Applicability Kit Number

Preventive

Modification

Sta 900, 910 and 920,

left and right sides

65-97861-6

65-97861-3

Supersedes 65-97869-3.

Inactive for future

procurement. Supersedes

65-97869-1. Kit

65-97861-3 together

with 65-89360-128 is

equivalent to 65-97869-6

Sta 910, left and

right sides

Sta 900 and 920,

and right sides

Sta 910 to 930

left

65-97861-1

65-97861-4

65-89360-128

Inactive for future

procurement. Supplemented

by 65-97861-4.

Inactive for future

procurement. This kit

together with 65-97869-1

is equivalent to

65-97869-3.

This kit together with

65-97869-3 is equivalent

to 65-97869-6.

May 3/74

REV. 3: Nov 30/89

727-53A0124

20

in

as

or

Usage Remarks
May 3/74

REV. 3: Nov 30/89

727-53A0124

21
May 3/74

REV. 3: Nov 30/89

727-53A0124

22
65-89360 - KIT, DOUBLER INSTALLATION, PRESSURE FLOOR, MAIN GEAR WHEEL WELL

-8 -7 -6

Quantity

-5 -1

Part Number Nomenclature

65-89360-1

65-89360-5

65-89360-6

65-89360-7

65-89360-8

2 2 2 2 2 6 5- 9 2 2 0-2(c)

1 1 1 65- 9 2 2 0-56(c)

2 2 2 2 2 6 5 -9 2 20-57(c)

1 65-89360-2

2 65-89360-3

1 1 1 65-89360-4(d)

1 6 5-89360-13(d)

1 6 5- 8 9360-14(d)

1 65-89360-15(d)

1 6 5-89360-16(d)

2 2 6 5-89360-21(d)

1 1 2 2 1 69-41867-1

1 1 2 2 1 90-4007-3009

2 2 2 6 4 BACB30FP6-5

4 13 11 BACB30FP6-6

2 2 2 BACB30FP6-7

2 2 2 2 BACB30FP8-5

4 8 4 BACB30FQ6-6

2 BACB30NE4-6

6 6 17 27 21 BACC30M6

6 6 6 6 BACC30M8

4 4 8 8 4 BACR15BB4A6(b)

6 6 6 6 BACR15BB8D10

6 6 6 6 4 BACR15BB8D12(a)

8 8 8 8 BACR15CE6D8

8 8 8 8 BACR15CE6D12

65-89360-9

65-89360-10

65-89360-11

65-89360-12

65-89360-128

1 65-89360-134

1 2 2 2 2 6 5 -9 2 2 0-2(c)

1 1 6 5 -9 2 2 0-56(c)

2 2 6 5 -9 2 2 0-57(c)

Kit

Kit

Kit

Kit

Kit

Rivet Kit

Rivet Kit

Rivet Kit

Doubler

Filler

Filler

Doubler

Doubler

Doubler

Doubler

Filler

Retainer

Seal

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Collar

Collar

Rivet

Rivet

Rivet

Rivet

Rivet

Kit

Kit

Kit

Kit

Kit

Bracket Installation

Rivet Kit

Rivet Kit

Rivet Kit

May 3/74

REV. 3: Nov 30/89 727-53A0124

23
65-89360 - (CONTINUED)

-134 -128 -12 -11

Quantity

-10 -9

Part Number Nomenclature

50-3361-2024

50-3361-38

1 1 65-89360-4(d)

1 65-89360-17(d)

1 65-89360-18(d)

1 65-89360-19(d)

2 1 65-89360-20(d)

2 2 65-89360-21(d)

1 . 65-89360-131

1 . 65-89360-132

1 65-89360-133

66-17308-1

69-20207-1

69-20207-3

69-20207-4

1 . 1 69-41867-1

.1 . 1 90-4007-3009

AN320-5

AN380-2-1

AN960-10L

AN960D516

.. . . . AN960PD10

4 . BACB30FN6A6U

2 2 6 4 BACB30FP6-5

13 . 11 BACB30FP6-6

2 2 2 BACB30FP6-7

2 2 2 BACB30FP8-5

4 8 4 BACB30FQ6-6

2 BACB30NE4-6

4 BACB30FP6A5

2 .. BACB30FP6A6

6 6 17 27 21 BACC30M6

6 6 6 BACC30M8

BACP18C-DD3-178

BACP30J7

4 8 8 4 BACR15BB4A6(b)

6 6 6 BACR15BB8D10

19 6 6 6 4 BACR15BB8D12(a)

10 . . . BACR15BB8D14

8 8 8 BACR15CE6D8

8 8 8 . BACR15CE6D12

NAS1105-22D

NAS623-3-3

NAS679A3W

MS20220-2

MS24665-132

Radius Filler

Radius Filler

Filler

Doubler

Doubler

Doubler

Doubler

Filler

Doubler

Clip

Clip

Fairlead

Bracket

Bracket

Bracket

Retainer

Seal

Nut

Pin

Washer

Washer

Washer

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt, 1/64 OS

Bolt, 1/64 OS

Collar

Collar

Pin

Pulley

Rivet

Rivet

Rivet

Rivet

Rivet

Rivet

Bolt

Screw

Nut

Pulley

Cotter Pin

May 3/74

REV. 3: Nov 30/89

727-53A0124

24

2

2

2

1

1

1

1

3

1

1

4

1

2

1

4

4

2

3
65-97861 - KIT, STRAP INSTALLATION,PRESSURE FLOOR MAIN GEAR WHEEL WELL

-6 -5 -4 -3

Quantity

-2 -1

Part Number Nomenclature

65-97861-1

65-97861-2

65-97861-3

65-97861-4

65-97861-5

65-97861-6

65-9 220-2(c)

65-18745-415(d)

65-18745-416(d)

65-18745-417(d)

65-18745-418(d)

1 65-18745-419(d)

1 65-18745-420(d)

65-18745-421(d)

65-18745-422(d)

65-18745-423(d)

65-18745-424(d)

65-18745-425(d)

65-18745-426(d)

65-18745-427(d)

65-18745-428(d)

65-18745-429(d)

1 65-18745-430(d)

1 65-18745-431(d)

1 65-18745-432(d)

1 65-18745-433(d)

65-89360-11

65-89360-12

65-89360-19(d)

65-89360-20(d)

65-89360-128

Kit

Kit

Kit

Kit Supplemental

Kit Supplemental

Kit

Rivet Kit

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Strap

Subkit

Subkit

Strap

Strap

Subkit

May 3/74

REV. 3: Nov 30/89

727-53A0124

25

2

1

1

1

1

1

1

2

1

2

2

1

1

1

1

1

1

1

1

1

1

1

2

1 1

1 1

1 1

1 1

1

1

2 2

1 1

2 2

2 2

1 1

1 1

1 1

1 1

1 1

1

1

1

1

2

1

1

1
65-97861 - (CONTINUED)

-6 -5 -4 -3

Quantity

-2 -1

Part Number Nomenclature

BACB30FP6-6

BACB30FP6-7

BACB30FP6-8

BACB30FP8-7

BACB30FP8-9

BACB30FQ6-7

BACB30FQ6-8

BACB30MC6-7

BACB30MC8-6

BACB30NE4-8

BACC30M6

BACC30M8

BACC30X6

BACC30X6

BACR15CE6D7

212 MS20470D6-12(a)

MS20470D6-14(a)

MS20470D8-12(a)

MS20470D8-14(a)

(a) MS20470D( )-( ) rivet and BACR15BB( )D( ) or BACR15ET(

used interchangeably.

)D( ) rivet may be

(b) MS20470A( )-( ) rivet optional to BACR15BB( )A( ) rivet.

(c) Contents of rivet kits are approximately as indicated in Table III.

(d) Indicated parts may be locally fabricated per drawings supplied with this

bulletin from 2024-T3 clad sheet per Specification QQ-A-250/5, stock size

as noted in Table IV. After trimming to shape, apply chemical film

treatment (Alodine or Iridite) and apply one coat of chemical and solvent

resistant primer (Ref BMS 10-11, Type I).

TABLE III

Rivet Kit Contents

Part Number

65-9220-2

BACR15BB6D7

BACR15BB6D8

BACR15BB6D10

BACR15BB6D12

BACR15ET7D7

BACR15ET7D8

BACR15ET7D12

31

26

45

34

Rivet Kit Quantity

65-9220-56 65-9220-57

67

62

13

12

May 3/74

REV. 3: Nov 30/89

727-53A0124

26

4

4

4

8

18

1

4

16

4

18

1

16

562

96

25

16

2

4

4 4

4

4

4

8

18

1

4

10 16

4

18

1

16

350

96

6 25

16

4

4

4

4

8

18

1

4

16

4

18

1

16

562

96

25

16

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Bolt

Collar

Collar

Collar

Collar

Rivet

Rivet

Rivet

Rivet

Rivet
2. The following materials are to be furnished by the operator.

Part Number or

Quantity Specification Nomenclature

1/2 Pint BMS 5-14(a) Adhesive

4 Quarts BMS 5-95(a) Sealant

1/2 Pint Q30-121(b) Adhesive

(a) Refer to applicable Boeing Material Specification for

qualified products.

(b) Dow-Corning Corporation

3901 South Saginaw Road

Midland, Michigan 48641-2721

(71984)

May 3/74 727-53A0124

REV. 3: Nov 30/89 27
B. Parts Required to Modify Spares

None

C. Special Tools and Equipment Required

No special tools or equipment are required to accomplish this

bulletin. Maintenance and overhaul tools may be required per any

manuals that are listed in Paragraph I.I., References, of this

bulletin. Operators should review their tool inventory to ensure tool

availability.

D. Existing Parts Accountability

None

May 3/74

REV. 3: Nov 30/89

727-53A0124

28
III. ACCOMPLISHMENT INSTRUCTIONS

NOTES: l.Observe all warning and caution notes in the referenced manual sections.

2. As recommended by the 727 Aging Fleet Structures Working Group, accomplish the modification per this service bulletin, Part III of the Accomplishment Instructions prior to, or upon the accumulation of 60,000 flights.

Part I - Inspection

A. Inspect pressure floor adjacent to Body Station 910 for cracks in both the right and left main wheel wells per Figure 1.

B. If no cracks are found, repeat inspection at maintenance intervals of 2000 flight cycles or less, until modified per Part III Preventive Modification.

C. If cracks are found, perform similar inspection of ends of beads in

pressure floor just forward and aft of Station 900 and 920 floor beams. Repair all cracks per Part II - Repair, and repeat inspection of unrepaired areas at maintenance intervals of 2000 flight cycles or less, until modified per Part III Preventive Modification. Optionally, if cracks do not exceed limits specified in Table V, stop drill cracks with 0.190 inch diameter drill, apply pressure and environmental sealant per operator's standard procedures and repair

per Part II within 600 flight cycles.

TABLE V

Crack Limits

Condition Crack Limit

One bead cracked and no cracks in 1.00 inch

adjacent beads.

Two adjacent beads cracked and no cracks 1.00 inch, combined in beads on both sides of cracked pair length

Three or more adjacent beads cracked. 0.35 inch per bead

D. If preventive modification straps have been installed at BS 910 only per Revision 1 of this service bulletin, inspect floor adjacent to Body Stations 900 and 920 at maintenance intervals of 2000 flight cycles or less, until preventive modification or repair is installed

at these stations also.

E. If repair was installed per the original issue of this bulletin, inspect those areas of the pressure floor adjacent to Body Station 900, 910 and 920, which are not covered by the repair doubler, at maintenance intervals of 2000 flight cycles or less, until terminating action or preventive modification straps or additional repair, as applicable, are installed at these stations.

May 3/74 72 7-53A0124 REV. 3: Nov 30/89 29
F. On Group 2 and 3 airplanes and on Group 1 airplanes preventively

modified per previous issues of this bulletin, inspect those areas of

the pressure floor between Body Station 910 and 930 and between

Buttock Line 0 and right Buttock Line 10, at maintenance intervals of

2000 flight cycles or less, until repaired per Part II or preventive

modification doubler is installed per Part III.B.

Part II - Repair

A. Install repair doublers and straps as follows and per Drawing

65-89360, Sheet 3, which details separate doubler and strap

configurations suitable for repair of cracks between Stations 900 and

910 only (Kit 65-89360-7 or -8), between 910 and 920 only (Kit

65-89360-9 or -10) or between 900 and 910 as well as between 910 and

920 (Kit 65-89360-5 or -6).

B. If expedited repair is required, the doubler may be installed, without

gaining access to the upper surface of the pressure floor, with blind

bolts, BACB30LB( )-( ), or Visu-Lok PLT210 or PLT 211 blind rivets, at

all fastener locations. If blind fasteners are installed, however,

they must be reinspected at intervals of approximately 2000 flight

cycles until replaced with fasteners specified of Drawing 65-89360 at

or prior to 10,000 flight cycles. Install blind bolts (Ref. 727

Structural Repair Manual, Subjects 51-30-02 and 51-30-05). Hole sizes

for installation of blind rivets are specified in Table VI. Airplanes

previously repaired that have utilized blind fasteners and have

exceeded 10,000 flight cycles should replace blind fasteners with

solid fasteners within 2000 flights cycles after receipt of this

Revision.

NOTES: 1. Shorter or longer doublers than those included in the kits

and shown on Drawing 65-89360, Sheet 3, may be installed

as a repair.

2. If existing repair doubler interferes with new repair, it

will be necessary to remove existing repair doubler and

install new repair that encompasses the old repair area.

3. Straps and their attaching fasteners included in

preventive modification Kit, 65-97861-3 or equivalent, are

to be used with the referenced repair kits, since

duplicate straps have not been provided.

4. Installation of the repair doubler described in the

original issue of this bulletin and as shown on Drawing

65-89360, Sheet 2, is adequate for repair but is no longer

recommended because of the extensive rework required to

accomplish subsequent terminating action.

May 3/74 727-53A0124

REV. 3: Nov 30/89 30
May 3/74

REV. 3: Nov 30/89

727-53A0124

31
Part III - Preventive Modification

NOTE: If not accomplished, perform inspection per Part I and accomplish

preventive modification or repair as required.

A. In areas of floor beams at Body Stations (BS) 900, 910 And 920 which

are not covered by repairs, install Straps, 65-18745-415 through -433

of Kit 65-97861-6 or equivalent per Drawing 65-18745, Sheet 3, Drawing

65-89360, Sheet 7, and as follows:

1. Trim straps as necessary to accommodate existing repairs. Apply

chemical film treatment (Alodine or Iridite) and one coat of

chemical and solvent resistant primer (Ref BMS 10-11, Type I) to

bare surfaces.

2. At locations designated "BM", remove existing fastener and

install MS20470D( )-( ) rivet. At locations designated "XF",

install BACB15CE( )D( ) rivet.

3. Remove and reinstall APU generator hoist fitting at BS 900, Left

Buttock Line (LBL) 18, With four BACB30FP6-8 bolts and BACC30M6

collars installed in 0.200 (+0.003 or -0.000) inch diameter

holes.

4. At the APU hoist attach points at BS 900, RBL 28 and BS 920. RBL

51, remove radius filler attaching fasteners and install four

Bolts BACB30FQ6-8 and collars BACC30M6 at each station in 0.200

(+0.003 or -0.000) inch diameter holes. Replace existing bolts

with BACB30NE4-8 bolts (2 places each station).

5. Remove two intercostal tee attach fasteners at BS 900, right and

left BL 30 and install Bolts BACB30FP6-7 and Collars BACC30M6 in

0.200 (+0.003 or -0.000) inch diameter holes.

6. Remove two intercostal tee attach fasteners at BS 900, right and

left BL 46 and install bolts BACB30FP8-7 or -9 and collars

BACC30M8 in 0.263 (+0.003 or -0.000) inch diameter holes.

7. Remove hydraulic tubing support bracket attach fasteners at BS

900, LBL 54 and install bolt BACB30MC8-6 and collar BACC30X8 in

0.263 (+0.003 or -0.000) inch diameter hole.

8. At BS 920, remove the nine aft fasteners at locations common to

the new straps between right and left BL 20 and BL 30 and replace

with BACB30MC6-7 bolts and BACC30X6 collars installed in 0.200

(+0.003 or -0.000) inch diameter holes.

9. Apply one coat of white enamel (Ref BMS 10-11, Type II) to

installed straps.

May 3/74 727-53A0124

REV. 3: Nov 30/89 32
B. In area between Body Stations (BS) 910 and 930 and between Buttock

Line (BL) 0 and right BL 10 which are not covered by repairs, install

Doubler 65-89360-131 per Drawing 65-89360, Sheet 7 and as follows:

1. Trim ends of Straps 65-18745-428, -429, -430, and -431 installed

in step III.B. as shown in zone Dll. Apply chemical film

treatment (Alodine or Iridite) and one coat of chemical and

solvent resistant primer to bare surface.

2. Remove and discard existing pulley bracket assembly 65-26196-3

two angles 65-18745-234 and filler 65-18745-225.

3. Remove existing fasteners as indicated on drawing installation

65-89360-128 shown in zone B10.

4. Remove and discard bracket 69-20207-3 from pulley bracket

69-20207-1.

5. Position doubler 65-89360-131 and drill No. 11 (0.191 inch

diameter) hole at locations designated "XZK 6", and drill No. F

(0.257 inch diameter) hole at locations designated "XZK 8".

6. Install doubler 65-89360-131, two angles 65-18745-234, filler

65-18745-225, bracket 69-20207-4, 65-89360-132, and 65-89360-133

using fastener BACR15BB( )D( ) at locations designated "XZK" with

manufactured head on upper side of web.

7. Apply one coat of white enamel (Ref BMS 10-11, Type II) to

installed doubler.

8. Install pulley bracket 69-20207-1 and two fairleads 66-17308-1.

9. Group 1 and 2 airplanes - Install two flap control pulleys

MS20220-2.

10. Group 3 airplanes - Install two flap control pulleys BACP30J7.

11. Adjust flap control pulleys ( on Group 1 and 2) MS20220-2 or (on

Group 3) BACP30J7 to align with outboard trailing edge flap control valve assembly 65-23552-() and inboard flap control shaft

assembly 65-24593-().

May 3/74 727-53A0124

REV. 3: Nov 30/89 33
Part IV - Terminating Action For Airplanes Repaired Per Original Issue or

Revision 1 of this service bulletin

A. If repair doubler was installed between Body Station (BS) 900 and

BS 910 or between BS 910 and BS 920 per original issue of this

bulletin, install straps of Kit 65-89360-11, or equivalent, at the

forward and aft edges of the doubler per Drawing 65-89360, Sheet 4,

and as follows:

1. If repaired, cut straps to length and apply chemical film

treatment (Alodine or Iridite) and one coat of chemical and

solvent resistant primer (Ref BMS 10-11, Type I) to bare surface.

2. Apply one coat of white enamel (Ref BMS 10-11, Type II) to

installed straps.

B. If repair doubler was installed between BS 900 and BS 920 per the

original issue of this bulletin, install straps of Kit 65-89360-12 at

forward and aft edges of doubler per Drawing 65-89360, Sheet 4, and

install strap and fasteners of preventive modification Kit 65-97861-3

at BS 910 per Drawing-65-89360, Sheet 3 and Steps A.1 and A.2 above.

C. If repair doubler was installed per Revision 1 of this bulletin,

install straps and fasteners of preventive modification Kit 65-97861-6

at applicable floor beam stations per Drawing 65-89360, Sheet 3, and

Steps A.1 and A.2 above.

May 3/74

REV. 3: Nov 30/89

727-53A0124

34
FIGURE 1. INSPECTION OF MLG WHEEL WELL PRESSURE FLOOR

May 3/74

REV. 3: Nov 30/89

727-53A0124

35
727-53A0124 (REV. 3) S/B DATED: NOVEMBER 30, 1989

FUSELAGE - MAIN WHEEL WELL PRESSURE FLOOR INSPECTION,

MODIFICATON AND REPAIR

AIRPLANES AFFECTED

(check one):

TITLE: PREPARED BY:

ORGANIZATION:

EVALUATION:

per S/B effectivity list

per corrected list below:

DATE:

TELEX CODE:

check ONE of the following check ONE of the following five circles seven circles.

- Will accomplish - Inspection - Being accomplished - Partial incorporation

- Have accomplished - Complete incorporation

- Service bulletin intent

- Will not accomplish

- Decision deferred (explain)

- Other (explain below)

not justify

COMMENTS: Bulletin Quality, Suggested Improvements, Other.

FOR ADDITIONAL COMMENTS USE REVERSE SIDE

Please forward this form to your Boeing Field Service Representative or mail directly to:

Boeing Commercial Airplanes

P.O. Box 3707

Seattle, WA 98124

Attention: R. G. Kelsey

Manager,

Service Bulletin Engineering

Mail Stop 2L-02

S/B NO.:

TITLE:

OPERATOR: