Commercial 

Airplanes 737

Service Bulletin

ALERT

Number: 737-52A1079

Original Issue: December 16, 1983

Revision 7: December 17, 2010

ATA System: 5231

SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification

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Copyright © 1989 The Boeing Company

Unpublished Work - All Rights Reserved

Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable

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This document includes proprietary information owned by The Boeing Company and/or one or more third parties.

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4.0
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BLANK PAGE
Table of Contents

Revision Transmittal Sheet ............................................ 5

Summary ...................................................... 9

1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 42

4. Process Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 52

3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 55

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

FIGURE 1: AFT CARGO DOOR INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

FIGURE 2: CORNER INSPECTION AND REWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

FIGURE 3: LOWER BEAM REPAIR - FORWARD END . . . . . . . . . . . . . . . . . . . . . . . . . 72

FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END . . . . . . . . . . . . . . . . . . . . . 77

FIGURE 5: LOWER BEAM REPAIR - AFT END . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

FIGURE 6: REPAIR PARTS - LOWER BEAM AFT END . . . . . . . . . . . . . . . . . . . . . . . . . 87

FIGURE 7: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

FIGURE 8: AFT CARGO DOOR - LOWER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

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FIGURE 9: AFT CARGO DOOR - UPPER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

FIGURE 10: AFT CARGO DOOR - UPPER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

FIGURE 11: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION FOR AIRPLANES WITH LOWER BEAM OUTER 'T' CHORD

REPAIR INSTALLED ON THE FORWARD END . . . . . . . . . . . . . . . . . . . . . . 101

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Commercial 

Airplanes 737

Service Bulletin

ALERT

Revision Transmittal Sheet Number: 737-52A1079

Original Issue: December 16, 1983

Revision 7: December 17, 2010

ATA System: 5231

SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification

This revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

More work is necessary on airplanes that have not accomplished the repair or preventive modification in

accordance with previous releases of this service bulletin. Do an ultrasonic inspection for cracks in the upper

and lower corner frames and a HFEC inspection for cracks in the upper and lower cross beams at the revised

time specified in Paragraph 1.E., Compliance.

More work is necessary on airplanes that have repair angles 65C25180-9, -43, -10, -11 or -12 installed in

accordance with previous issues of this service bulletin. Do the work in Paragraph 3.B., Work Instructions, Part

V - Corner Inspection and Rework in accordance with Revision 7 of this service bulletin at the revised time

specified in Paragraph 1.E., Compliance.

More work is necessary on airplanes that have accomplished the repair or preventive modification of the upper

or lower cross beams in accordance with previous releases of this service bulletin. Do supplemental structural

inspections of the cross beams at the times specified in Paragraph 1.E., Compliance. These supplemental

structural inspections provide compliance with 14 CFR 26.43 (c).

Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2000-06-13 R1 supersedes Airworthiness

Directive (AD) 98-25-06.

No new airplanes have been added or removed from the effectivity of this bulletin.

REASON FOR REVISION

This revision is sent to:

— Remove the option for repeat inspections and add a High Frequency Eddy Current (HFEC) inspection for

cracks in the beam.

— Remove the option to repair the upper edge frame using a Structural Repair Manual (SRM) procedure.

— Replace the HFEC inspection of the frames with an ultrasonic inspection.

— Inform operators that the corner reinforcing angles given in previous releases of this service bulletin have

been superseded by corner reinforcing angles with an increased edge margin.

— Inform operators that this revision provides supplemental structural inspections in compliance with 14 CFR

26.43 (c).

— Change the Lower Beam Outer 'T' Chord Repair on the forward end of the lower beam to include a joggle

of the replacement 'T' Chord.

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— Change the heat treatment of the replacement 'T' Chord A to 2024-0.

— Instruct operators to identify the aft cargo door part number which is currently installed on each airplane in

accordance with the original issue of Boeing Service Bulletin 737-52A1153 before further work is done.

— Instruct operators to also accomplish all applicable actions in accordance with the original issue of Service

Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance, if any cracks are found.

These sections were changed:

1. The Summary Background and Action sections are updated.

2. Summary illustration - Reinforcement angles are added to the lower corners of the aft cargo door.

3. Paragraph 1.C., Reason is updated.

4. Paragraph 1.D., Description is updated.

5. Paragraph 1.E., Compliance - The compliance information is changed.

6. Paragraph 1.F, Approval - An Alternative Method of Compliance (AMOC) statement is added. Also,

supplemental structural inspection information is added.

7. Paragraph 1.G., Manpower - The manpower information is updated.

8. Paragraph 1.H., Weight and Balance Changes - The SRM repair is removed from the table.

9. Paragraph 1.J., References - Non Destructive Test (NDT) Manual references, reference service bulletin

numbers and Federal Aviation Administration (FAA) Airworthiness Directives (AD) are added. Supplemental

Structural Inspection Document numbers are also added. SRM 51-40-3 reference is removed.

10. Paragraph 1.K., Publications Affected - A statement for Damage Tolerance Based Structural Inspections

is added.

11. Paragraph 2.C.1., Kits/Parts - Replacement parts are added to one kit table.

12. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - Fasteners are added to the table for the

repair parts.

13. Paragraph 3.A., General Information - Note added, reference the use of the words "refer to" and "in

accordance with".

14. Paragraph 3.B., Work Instructions - Supplemental Structural Inspections are added. Also, the option to

repair the upper edge frame using an SRM procedure is removed.

15. Figures 1 through 5 are updated.

16. Figures 7 through 11 are added to provide Supplemental Structural Inspections.

Paragraph 1.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity

paragraph for changes.

Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location

of important changes.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Pages with no vertical lines have no important changes.

REVISION HISTORY

Original Issue: December 16, 1983

Revision 1: December 15, 1988

Revision 2: July 20, 1989

Revision 3: May 17, 1990

Revision 4: February 21, 1991

Revision 5: May 16, 1996

Revision 6: November 18, 1999

Revision 7: December 17, 2010

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BOEING SERVICE BULLETIN 737-52A1079

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BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

ALERT

Summary Number: 737-52A1079

Original Issue: December 16, 1983

Revision 7: December 17, 2010

ATA System: 5231

SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification

THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH

1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO

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

THE NEW OWNER.

CONCURRENT REQUIREMENTS

None.

BACKGROUND

Based on a structural review of the 737 airplane, incorporation of the modification in accordance with this service

bulletin is recommended on aging airplanes.

As of 1996, several operators had reported cracks 0.75 to 20 inches long in the forward and aft lower corner of

the aft cargo door frames. The airplanes had 10,100 to 38,000 flight hours and 14,000 to 54,000 flight cycles.

In addition, some of the doors had a cracked web in the beam common to the forward lower stop fitting,

approximately 3 inches aft of the fitting. In some of the cases, the frame and beam cracks were discovered after

the airplane had experienced pressurization problems. Cracking is caused by fatigue as a result of cabin

pressurization cycles.

Since 1996, there have been additional reports of cracked frames and cracked beam webs. One airplane with

86,400 hours and 35,400 flight cycles experienced a rapid decompression caused by an approximately 12 inch

long crack in the aft lower frame corner. The lower beam web and outer 'T' chord were also cracked.

Since 1996, there have also been at least two reports of cracking in the lower beam outer "T" chord. One airplane

had only the outer "T" chord cracked and had about 63,800 flight hours and 66,500 flight cycles. On the other

airplane, the frame and "T" chord were cracked all the way through.

The inspection, repair and preventive modification of cross beam D on the aft cargo door is the subject of the

original issue of Boeing Service Bulletin 737-52-1154 .

The Federal Aviation Administration (FAA) has issued an Airworthiness Directive (AD) which requires incorporation

of Revision 5 or 6 of this bulletin.

Boeing Service Related Problem (SRP) 737-SRP-52-0077 is related to this service bulletin.

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ACTION

Identify the aft cargo door assembly part number which is currently installed on each airplane in accordance

with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is found to be from an

airplane in the line number range greater than 873, accomplish all applicable actions in accordance with Service

Bulletin 737-52A1153 , Original Issue.

For Groups 1, 2 and 3 airplane doors: If an airplane is found to have a door configuration that was delivered

between line numbers 6 and 873, inclusive, do the following: Do an inspection for cracks in the forward and aft

frames at the upper and lower corners. Use visual and ultrasonic inspection techniques to look for cracking in

the radius of the frames. Also, do a HFEC inspection for cracking in the lower and upper beam web and outer

"T" chord. For airplanes that have previously installed reinforcement angle 65C25180-9, -43, -10, -11 or -12, do

an inspection for adequate edge margin and cracks.

For airplanes that have previously installed repairs or modifications to the upper or lower cross beam, do

supplemental structural inspections at the times given in Paragraph 1.E., Compliance . These supplemental

structural inspections provide compliance with 14 CFR 26.43 (c).

The modification requires installation of a steel reinforcement angle in each corner of the door and the installation

of a web doubler on the upper and lower beams.

In addition, if any cracks are found, accomplish all applicable actions in accordance with the original issue of

Service Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance .

EFFECTIVITY

737-200, -200C, -300, and -400 series airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected

airplanes.

COMPLIANCE

See Paragraph 1.E., Compliance.

Federal Aviation Administration (FAA) Airworthiness Directive AD 90-06-02, AD 98-25-06, AD 98-11-04 R1, AD

2000-06-13 R1, AD 2008-08-23 and AD 2008-09-13 are related to this service bulletin.

INDUSTRY SUPPORT INFORMATION

This service bulletin was first released before October of 1994. Thus industry support for affected airplanes

depends upon whether you ever filed a warranty claim with Boeing on this service bulletin.

MANPOWER

See Paragraph 1.G., Manpower.

MATERIAL INFORMATION

Refer to Paragraph 2.A., Material - Price and Availability.

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BLANK PAGE
Commercial 

Airplanes 737

Service Bulletin

ALERT

Number: 737-52A1079

Original Issue: December 16, 1983

Revision 7: December 17, 2010

ATA System: 5231

SUBJECT: DOORS - Aft Cargo - Frame and Beam Inspection, Repair and Modification

THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH

1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO

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

THE NEW OWNER.

1. PLANNING INFORMATION

A. Effectivity

1. Airplanes

This service bulletin is for the airplanes shown below.

Refer to Service Bulletin Index Document D6-19567, Part 3 for Airplane Variable Number, Line

Number, and Serial Number data.

GROUP CONFIGURATION DESCRIPTION

737-200 and -200C airplanes, line numbers 6 - 571. These airplanes

are the same as Group 2 airplanes except for slightly different door

stop cutouts in the frame which required different repair kit parts.

1 -

737-200 and -200C airplanes, line numbers 510 - 873. These

airplanes are the same as Group 1 airplanes except for slightly

different door stop cutouts in the frame which required different repair

kit parts.

2 -

737-200/-200C/-300 and -400 airplanes, line numbers 874 - 1642.

These airplanes require an inspection to determine the aft cargo door

configuration.

3 -

Airplane Models:

737-200, 737-200C, 737-300, 737-400

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Variable Number Group

PG001 - PG075 1

PG199 1

PG201 - PG230 1

PG251 - PG255 1

PG271 - PG279 1

PG301 - PG314 1

PG331 - PG332 1

PG351 - PG356 1

PG375 1

PG401 - PG403 1

PG431 - PG442 1

PG471 - PG475 1

PG501 - PG505 1

PG571 - PG586 1

PG621 - PG630 1

PG651 - PG652 1

PG701 - PG705 1

PH001 1

PH011 - PH013 1

PH021 - PH024 1

PH701 - PH715 1

PH731 - PH732 1

PH741 - PH743 1

PJ001 - PJ006 1

PJ007 - PJ009 2

PJ031 - PJ032 1

PJ071 - PJ072 1

PJ101 - PJ111 1

PJ112 - PJ119 2

PJ201 - PJ219 1

PK026 - PK029 1

PK041 - PK053 1

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Variable Number Group

PK061 - PK070 1

PK081 1

PK082 2

PK091 - PK099 1

PK101 - PK103 1

PK111 - PK120 1

PK141 - PK146 1

PK201 - PK204 2

PK211 - PK212 1

PK213 - PK215 2

PK216 - PK220 3

PK221 1

PK222 - PK223 2

PK231 - PK235 1

PK236 - PK240 2

PK241 1

PK251 - PK258 1

PK271 - PK273 1

PK274 2

PK281 1

PK282 - PK289 2

PK291 1

PK301 - PK306 1

PK307 - PK310 2

PK311 - PK314 1

PK315 - PK318 2

PK341 1

PK351 - PK352 1

PK353 - PK361 2

PK391 1

PK431 - PK433 2

PK451 1

PK452 2

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Variable Number Group

PK461 - PK465 1

PK466 - PK469 2

PK495 2

PK501 1

PK502 - PK503 2

PK504 3

PK511 1

PK512 - PK514 2

PK515 3

PK519 3

PK521 - PK524 2

PK525 - PK528 3

PK541 - PK564 2

PK565 3

PK581 2

PK591 - PK599 2

PK601 - PK617 2

PK621 - PK630 2

PK631 - PK637 3

PK641 - PK642 2

PK661 - PK663 2

PK664 - PK666 3

PK671 - PK678 2

PK679 - PK681 3

PK691 - PK696 2

PK697 3

PK711 - PK716 2

PK731 - PK749 2

PK750 - PK765 3

PK771 - PK779 2

PK801 - PK802 2

PK803 - PK804 3

PK819 - PK826 2

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Variable Number Group

PK827 3

PK830 2

PK861 - PK863 2

PK871 - PK874 2

PK881 - PK884 2

PK901 - PK932 2

PK933 - PK938 3

PK971 - PK974 2

PL001 1

PL002 - PL023 2

PL024 - PL028 3

PL061 2

PL081 2

PL101 - PL112 2

PL113 3

PL151 2

PL171 2

PL172 3

PL201 - PL203 2

PL221 3

PL401 - PL412 2

PL413 - PL417 3

PL421 2

PL441 2

PL451 - PL454 2

PL455 - PL456 3

PL471 2

PL491 2

PL501 - PL506 2

PL551 - PL561 2

PL562 3

PL581 2

PL601 2

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Variable Number Group

PL602 - PL603 3

PL611 3

PL621 - PL626 3

PL631 - PL632 3

PL711 - PL712 1

PL716 - PL743 1

PL744 - PL745 2

PL746 - PL747 3

PL756 1

PL758 1

PL761 - PL767 1

PL768 - PL770 2

PL781 - PL782 1

PL783 2

PL784 - PL788 3

PL793 1

PL801 - PL803 1

PM001 - PM002 2

PM003 - PM006 3

PM016 - PM017 3

PM021 - PM023 2

PM051 - PM066 3

PM101 - PM104 2

PM105 - PM119 3

PM141 - PM142 2

PM171 3

PM181 3

PM251 - PM255 3

PM281 - PM283 3

PM381 3

PN001 - PN002 3

PN021 - PN043 3

PN081 - PN086 3

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Variable Number Group

PN101 - PN117 3

PN131 - PN163 3

PN401 - PN420 3

PN431 - PN433 3

PN451 - PN456 3

PN471 - PN474 3

PN481 3

PN491 - PN493 3

PN501 - PN502 3

PN511 - PN512 3

PN521 3

PP001 - PP047 3

PP101 - PP139 3

PP161 - PP169 3

PP181 - PP197 3

PP201 - PP205 3

PP221 3

PP231 - PP243 3

PP281 - PP286 3

PP301 - PP305 3

PP351 - PP353 3

PP376 - PP384 3

PP391 - PP393 3

PP401 - PP440 3

PP471 - PP475 3

PP501 - PP507 3

PP521 - PP522 3

PP631 - PP634 3

PP651 - PP652 3

PP671 - PP699 3

PP701 - PP733 3

PP771 - PP779 3

PP801 - PP804 3

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ALERT ALERT
Variable Number Group

PP821 - PP827 3

PP831 - PP848 3

PP851 - PP852 3

PP861 - PP872 3

PP891 - PP899 3

PP901 - PP914 3

PP931 - PP936 3

PP946 - PP948 3

PP951 - PP952 3

PP961 - PP965 3

PP981 - PP984 3

PP991 3

PQ001 - PQ012 3

PQ026 - PQ041 3

PQ051 - PQ065 3

PQ086 - PQ090 3

PQ101 - PQ145 3

PQ221 - PQ222 3

PQ231 - PQ236 3

PQ241 - PQ243 3

PQ251 3

PV001 - PV010 3

PW001 - PW005 3

PW061 3

PW091 3

PX071 1

PX701 1

PY001 - PY008 1

PY021 - PY022 1

PY031 1

PY036 - PY037 1

PY046 - PY048 1

PY051 - PY053 1

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ALERT ALERT
Variable Number Group

PY056 - PY057 3

PY101 - PY103 1

PY111 - PY113 1

PY131 - PY133 1

PY134 - PY135 2

PY141 - PY143 1

PY151 - PY152 1

PY153 - PY154 2

PY156 - PY157 1

PY161 - PY162 1

PY166 1

PY191 1

PY201 1

PY221 - PY222 1

PY231 2

PY241 - PY244 2

PY270 2

PY271 - PY274 1

PY275 2

PY281 1

PY286 1

PY301 - PY304 1

PY321 - PY323 1

PY341 - PY346 1

PY361 - PY362 1

PY381 1

PY401 1

PY409 - PY410 3

PY411 1

PY421 2

PY422 3

PY441 2

PY451 2

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ALERT ALERT
Variable Number Group

PY461 - PY462 2

PY463 3

PY591 - PY595 3

PY611 1

PY612 2

PY621 2

PY631 2

PY651 2

PY671 - PY672 3

PY721 3

PY741 3

2. Spares Affected

Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts

Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for

the recommended use.

B. Concurrent Requirements

None.

C. Reason

As a result of the FAA sponsored Aging Fleet conference, a 737 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 737 airplanes.

Accomplishment of the modification in accordance with this bulletin will reduce the possibility of fatigue

cracks in the aft cargo door. Cracks in the aft cargo door frame may propagate and result in an inability

to maintain cabin pressurization.

As of 1996, several operators had reported cracks 0.75 to 20 inches long in the forward and aft lower

corner of the aft cargo door frames. The airplanes had 10,100 to 38,000 flight hours and 14,000 to

54,000 flight cycles. In addition, some of the doors had a cracked web in the beam common to the

forward lower stop fitting, approximately three inches aft of the fitting. In some of the cases, the frame

and beam cracks were discovered after the airplane had experienced cabin pressurization problems.

Cracking is caused by fatigue as a result of cabin pressurization cycles.

Since 1996, there have been additional reports of cracked frames and cracked beam webs. One airplane

with 86,400 hours and 35,400 flight cycles experienced a rapid decompression caused by an

approximately 12 inch long crack in the aft lower frame corner. The lower beam web and outer "T"

chord were also cracked.

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ALERT ALERT
Since 1996, there have also been at least two reports of cracking in the lower beam outer "T" chord.

One airplane had only the outer "T" chord cracked and had approximately 63,800 flight hours and

66,500 flight cycles. The other airplane had the outer "T" chord and the frame cracked all the way

through.

The inspection, repair and preventive modification of cross beam D on the aft cargo door is the subject

of the original issue of Boeing Service Bulletin 737-52-1154 .

Boeing is aware that doors requiring inspection, repair, and modification in accordance with this service

bulletin may be used on airplanes (Group 3 airplanes) originally delivered with doors which do not

require the service bulletin inspections or modifications. This service bulletin addresses these doors.

The Federal Aviation Administration (FAA) has issued an Airworthiness Directive (AD) which requires

incorporation of Revision 5 or 6 of this bulletin.

Revision 1 was issued to advise operators that some aft cargo door corner reinforcement kits may

have been delivered with an incorrectly manufactured angle that if installed may have four fasteners

with inadequate edge margin. New Kit and supplemental kit information was provided and updated

drawings provided.

Revision 2 of this bulletin was issued to provide the recommendations of the Aging Fleet 737 Structures

Working Group and to lower the inspection threshold on the door frames and beams from 25,000 flight

cycles to 12,000 flight cycles.

Revision 3 of this service bulletin was issued to advise operators that installation of reinforcement angle

65C25180-9 or -43 may result in a short edge margin condition. This condition may appear between

the angle and fastener locations common to the outer skin. New kit and part information were provided,

along with updated drawings.

Revision 4 of this service bulletin was sent to add the circle note indicators to Figure 2 that were

accidentally ignored when Revision 3 was released. Indicators were added to the text notes and

locations in the illustration were corrected.

Revision 5 of this service bulletin was sent to advise operators that installation of reinforcement angles

65C25180-10, -11 and -12, included in corner reinforcement kits 65C25180-3, -44 and -46, can result

in a short edge margin condition. Also, the minimum allowable edge margin was changed from 0.38

inch to 0.32 inch. This service bulletin revision provided corner reinforcement kit 65C25180-47 and

supplemental kit 65C25180-51 that included reinforcement angles with sufficient material added to

both flanges. The new reinforcement angles were for the upper aft, lower forward and lower aft corners.

New kit and part information were provided, along with updated drawings.

Revision 6 of this service bulletin was sent to:

— Add Group 3 airplanes to the effectivity. These airplanes may have a Group 1 or 2 airplane aft

cargo door installed on them which requires inspection, repair, or modification.

— Add a High Frequency Eddy Current (HFEC) inspection for cracks in the frames of doors that do

not have steel reinforcement angles.

— Add an inspection for cracks in the upper and lower beam outer 'T' chord of doors that do not have

the lower beam reinforcement doubler.

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ALERT ALERT
— Add repair instructions for the lower beam outer "T" chord.

— Remove the two inch stop-drilled crack allowable.

— Update Paragraph 1.F., Approval, to make Revisions 4, 5, and 6 of this service bulletin an Alternative

Method of Compliance (AMOC) to AD 90-06-02, and to make Revision 6 of this service bulletin

an AMOC to AD 98-25-06.

Revision 7 of this service bulletin is sent to:

— Remove the option for repeat inspections and add a High Frequency Eddy Current (HFEC)

inspection for cracks in the beam.

— Remove the option to repair the upper edge frame using a Structural Repair Manual (SRM)

procedure.

— Replace the HFEC inspection of the frames with an ultrasonic inspection.

— Inform operators that the corner reinforcing angles given in previous releases of this service bulletin

have been superseded by corner reinforcing angles with an increased edge margin.

— Inform operators that this revision provides supplemental structural inspections in compliance with

14 CFR 26.43 (c).

— Change the Lower Beam Outer 'T' Chord Repair on the forward end of the lower beam to include

a joggle of the replacement 'T' Chord.

— Change the heat treatment of the replacement 'T' Chord A to 2024-0.

— Instruct operators to identify the aft cargo door part number which is currently installed on each

airplane in accordance with the original issue of Boeing Service Bulletin 737-52A1153 before

further work is done.

— Instruct operators to also accomplish all applicable actions in accordance with the original issue

of Service Bulletin 737-52-1154 at the time specified in Paragraph 1.E., Compliance, if any cracks

are found.

Boeing Service Related Problem (SRP) 737-SRP-52-0077 is related to this service bulletin.

D. Description

Identify the aft cargo door assembly part number which is currently installed on each airplane in

accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the door is

found to be from an airplane in the line number range greater than 873, accomplish all applicable

actions in accordance with Service Bulletin 737-52A1153 , Original Issue.

For Groups 1, 2 and 3 airplane doors: If an airplane is found to have a door configuration that was

delivered between line numbers 6 and 873, inclusive, do the following: Do an inspection for cracks in

the forward and aft frames at the upper and lower corners. Use visual and ultrasonic inspection

techniques to look for cracking in the radius of the frames. Also, do a HFEC inspection for cracking in

the web and outer "T" chord of the upper and lower beams.

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ALERT ALERT
— If a crack is found in an upper or lower corner frame web, replace the damaged frame and install

the preventive modification kits on the frames and on the beams.

— If a crack is found in the web of the upper or lower beam, trim out the crack and install the repair

kits on the frames and on the beams. The frame preventive modification kit requires the installation

of a steel reinforcement angle in each corner of the door on the exterior of the door frame under

the outer skin and door seal retainer. The beam preventive modification/repair kit requires the

installation of a bent-up web doubler on the forward and aft ends of the beam.

— If a crack is found in the web and "T" chord of the lower beam, or in the outer "T" chord only, trim

out the web crack and do the repair in accordance with this bulletin. The repair for the aft end of

the lower beam requires the installation of the preventive modification kit, two splice angles (operator

supplied), and a new section of "T" chord (operator supplied). The repair for the forward end of

the lower beam requires the installation of new repair parts which are all operator supplied: a new

bent-up repair doubler, fillers, splice angles, and a new section of "T" chord.

— If a crack is found in the "T" chord of the upper beam, contact Boeing.

— If no cracks are found in the frames or beams, do the preventive modification in accordance with

this service bulletin.

— Do Supplemental Structural Inspections at the times shown in Paragraph 1.E., Compliance .

— In addition, if any cracks are found, accomplish all applicable actions in accordance with Service

Bulletin 737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance .

If you have previously installed reinforcement angles 65C25180-9 or -43, -10, -11 or -12, do an inspection

for adequate edge margin and cracks. If cracks are found or the edge margin is not adequate, replace

the angles with 65C25180-52, 53, 54 and 55. If no cracks are found and the edge margins are adequate,

no further action is required on the retrofit angles in accordance with this service bulletin.

More work is necessary on airplanes that have accomplished the repair or preventive modification of

the upper or lower cross beams in accordance with previous releases of this service bulletin. Do

supplemental structural inspections of the cross beams at the times specified in Paragraph 1.E.,

Compliance. These supplemental structural inspections provide compliance with 14 CFR 26.43 (c).

Airplane effectivity is divided into three groups. Group 1 and 2 airplanes are 737-200 and -200C airplanes

line numbers 6 through 873. Group 1 airplane doors are the same as Group 2 airplane doors except

for slightly different door stop cutouts in the frame which required different repair kit parts. Group 3

airplanes are 737-200, -200C, -300, and -400 airplanes line numbers 874 through 1642.

Based on a structural review of the 737 airplane, the modifications in accordance with the inspections

of this service bulletin should be accomplished within 4,500 flight cycles from the date of Revision 7 of

this service bulletin.

Revision 1 - Airplanes previously modified with corner reinforcement kit 65C25180-3 require inspection

to ensure that a correctly configured angle was installed. If an incorrectly configured angle was installed

inspection is required to ensure that adequate edge margin exists for attach fasteners common to

reinforcement angle and the two forward upper door stops. If an inadequate edge margin exists

inspection is required for cracks in the angle. If cracks are found, the angle is replaced. If no cracks

are found, repeat inspections at every structural inspection period (D check) intervals until the angle

is replaced with a correctly configured angle, in accordance with Revision 3.

Revision 2 - Airplanes modified in accordance with Part II of the Accomplishment Instructions of Revision

1 of this service bulletin do require additional work, in accordance with Revision 3.

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ALERT ALERT
Revision 3 or 4 - Airplanes previously modified with corner reinforcement kit 65C25180-44 or have had

angle 65C25180-9 or -43 installed required additional inspection to ensure that adequate edge margin

exists for attach fasteners common to reinforcement angle and outer skin. If inadequate edge margin

exists, inspect angle for cracks. If cracks were found, replace angle. If no cracks were found, repeat

inspection every Structural Inspection Period (D check) until angle is replaced with 65C25180-45 to

provide proper edge margin.

Revision 5 - Airplanes previously modified with the installation of angles 65C25180-10, 65C25180-11,

and 65C25180-12 will require additional inspections to ensure that adequate edge margin exists for

attach fasteners common to door stop fittings and reinforcement angle. If inadequate edge margin

exists, inspect angle for cracks. If cracks are found, replace angle. If no cracks are found, repeat

inspection every Structural Inspection Period (D check) until angles are replaced with 65C25180-48,

65C25180-49 and 65C25180-50 to provide proper edge margin.

Revision 6 - Airplanes modified in accordance with Revision 5 of this service bulletin require no more

work.

Revision 7 - More work is necessary as follows:

— More work is necessary on airplanes that have not accomplished the repair or preventive

modification in accordance with previous releases of this service bulletin. Do an ultrasonic inspection

for cracks in the upper and lower corner frames and a HFEC inspection for cracks in the upper

and lower cross beams at the revised time specified in Paragraph 1.E., Compliance.

— More work is also necessary on airplanes that have repair angles 65C25180-9, -43, -10, -11 or

-12 installed in accordance with previous issues of this service bulletin. Do the work in Paragraph

3.B., Work Instructions, Part V - Corner Inspection and Rework in accordance with Revision 7 of

this service bulletin at the revised time specified in Paragraph 1.E., Compliance.

— More work is necessary on airplanes that have accomplished the repair or preventive modification

of the upper or lower cross beams in accordance with previous releases of this service bulletin.

Do supplemental structural inspections of the cross beams at the times specified in Paragraph

1.E., Compliance.

Prior or concurrent incorporation of the Service Bulletins listed below are suggested on commonly

affected airplanes. These bulletins have some common access requirements:

737-52-1051 - Lower Cargo Door Latch Spring Relocation and Replacement.

737-52-1063 - Lower Cargo Door Hinge Attach Bolt Inspection.

737-52-1065 - Forward and Aft Cargo Door Stop Fittings Inspection and Replacement.

737-52-1154 - Aft Cargo Door Cross Beam D Inspection, Repair and Preventive Modification.

This service bulletin is listed in Boeing Document D6-38505.

The work in this service bulletin is done in the maintenance zone(s) given below.

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ALERT ALERT
Group 1-3:

Affected Maintenance Zones

Model Zone

737-200, 737-200C 2-19

Group 3:

Affected Maintenance Zones

Model Zone

737-300, 737-400 219

E. Compliance

Federal Aviation Administration (FAA) Airworthiness Directives AD 90-06-02 , AD 98-25-06 , AD

98-11-04 R1, AD 2000-06-13 R1, AD 2008-08-23 and AD 2008-09-13 are related to this service bulletin.

Accomplish the work in accordance with Revision 7 of this service bulletin at the times shown in the

tables that follow.

Table 1: Determination of door configuration (all airplanes), and High Frequency Eddy Current (HFEC)

and Ultrasonic Inspections for airplanes not modified and not repaired in accordance with the Original

Issue or Revisions 1, 2, 3, 4, 5, 6 of this service bulletin.

Condition Action Compliance Time

Within 4,500 door flight

cycles from the date of

Revision 7 to this Service Bulletin. (a)

Determine door configuration in accordance

with Service Bulletin 737-52A1153, Original

Issue, Paragraph 3.B.1.

All Groups.

At the time given in

737-52A1153, Original

Issue.

Accomplish all applicable actions in accordance

with the original issue of Service Bulletin 737-

52A1153.

Door found to be from an airplane

with a line number range greater

than 873.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin. (a)

Do one-time HFEC and ultrasonic inspections

of the upper and lower corner frames and the

upper and lower cross beams for cracks in accordance with Work Instructions, Part I - Access

and Part II - Inspection. (a)

Doors found to be from an airplane

in the line number range between

6 and 873 without either the Modification or Repair accomplished in

accordance with the Original Issue

or Revisions 1, 2, 3, 4, 5 and 6 of

this service bulletin.

Do the modification in accordance with Work Before further flight. (a)

Instructions, Part III - Preventive Modification.

No crack(s) found in the upper and

lower corner frames or the upper

and lower cross beams.

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ALERT ALERT
Table 1: Determination of door configuration (all airplanes), and High Frequency Eddy Current (HFEC)

and Ultrasonic Inspections for airplanes not modified and not repaired in accordance with the Original

Issue or Revisions 1, 2, 3, 4, 5, 6 of this service bulletin.

Condition Action Compliance Time

Do the beam repair in accordance with Work Before further flight.

Instructions.

Crack(s) found in the upper or lower

beam.

Accomplish actions in accordance with Tables Before further flight.

1 through 4 of Service Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

(a)

Replace the frame. Do the frame modification Before further flight.

in accordance with Work Instructions, Part III -

Preventive Modification.

Crack(s) found in an upper corner

frame.

Accomplish actions in accordance with Tables Before further flight.

1 through 4 of Service Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

(a)

Replace the damaged frame in accordance Before further flight.

with Work Instructions, Part IV - Lower Frame

Replacement for Aft and Forward Frames and

do the modification in accordance with Work

Instructions, Part III - Preventive Modification.

Crack(s) found in a lower corner

frame.

Accomplish actions in accordance with Tables Before further flight.

1 through 4 of Service Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

(a)

(a) NOTE: This is a new requirement of Revision 7 of this service bulletin. Compliance requirements of AD

90-06-02 amendment 39-6489 and AD 2000-06-13 R1 amendment 39-12317 still apply.

Table 2: Supplemental Inspection for airplanes with reinforcement angles 65C25180-9, -43, -10, -11 or

-12 installed

Condition Action Compliance Time

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin. (a)

Inspect lower corner frames to determine if door

has reinforcement angles 65C25180-9, -43, -

210, -11, or -12 installed in accordance with

the original issues, Revision 1, 2, 3 or 4 of this

service bulletin.

All Groups.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin. (a)

Do a one-time general visual inspection for

edge margin and detailed inspection for cracks

in accordance with Work Instructions, Part V -

Corner Inspection and Rework.

Airplanes with reinforcement angles

65C25180-9, -43, -10, -11 or -12

installed in accordance with the

original issue, Revision 1, 2, 3 or 4

of this service bulletin.

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ALERT ALERT
Table 2: Supplemental Inspection for airplanes with reinforcement angles 65C25180-9, -43, -10, -11 or

-12 installed

Condition Action Compliance Time

Airplanes without reinforcement No further action is required. -

angles 65C25180-9, -43, -10, -11

or -12 installed.

Replace the corner reinforcement angle in ac- Before further flight. (a)

cordance with Work Instructions, Part III - Preventive Modification.

Crack(s) found in corner reinforcement angle or edge margin is not

adequate.

Accomplish actions in accordance with Tables Before further flight.

1 through 4 of Service Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

(a)

No crack(s) found in corner rein- No further action is required. -

forcement angles and edge margin

is adequate.

(a) NOTE: This is a new requirement of Revision 7 of this service bulletin. Compliance requirements of AD

90-06-02 amendment 39-6489 and AD 2000-06-13 R1 amendment 39-12317 still apply.

Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

preventive modification is installed,

whichever comes

first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the forward end of the lower cross beam in accordance with the

Original Issue or Revisions 1, 2, 3, 4, 5,

6 or 7 of this service

bulletin and the door

flight cycles are

known.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

preventive modification is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the forward end of the lower cross beam in accordance with the

Original Issue or Revisions 1, 2, 3, 4, 5,

6 or 7 of this service

bulletin and the door

flight cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

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ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

preventive modification is installed,

whichever comes

first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the aft

end of the lower

cross beam in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6

or 7 of this service

bulletin and the door

flight cycles are

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

preventive modification is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the aft

end of the lower

cross beam in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6

or 7 of this service

bulletin and the door

flight cycles are not

known.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

31 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

preventive modification is installed,

whichever comes

first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the forward end of the upper cross beam in

accordance with the

Original Issue or Revisions 1, 2, 3, 4, 5,

6 or 7 of this service

bulletin and the door

flight cycles are

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before urther flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

32 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

preventive modification is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the forward end of the upper cross beam in

accordance with the

Original Issue or Revisions 1, 2, 3, 4, 5,

6 or 7 of this service

bulletin and the door

flight cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

preventive modification is installed,

whichever comes

first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the aft

end of the upper

cross beam in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6

or 7 of this service

bulletin and the door

flight cycles are

known.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

33 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

preventive modification is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a preventive modification

installed on the aft

end of the upper

cross beam in accordance with the Original Issue or Revisions 1, 2, 3, 4, 5, 6

or 7 of this service

bulletin and the door

flight cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

lower beam outer "T"

chord repair is installed, whichever

comes first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a lower beam outer "T"

chord repair installed

on the forward end

of the lower cross

beam in accordance

with this revision of

this service bulletin

and the door flight

cycles are known.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

34 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

lower beam outer "T"

chord repair is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a lower beam outer "T"

chord repair installed

on the forward end

of the lower cross

beam in accordance

with this revision of

this service bulletin

and the door flight

cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Before 56,000 total

door flight cycles, or,

Within 18,000 door

flight cycles after the

lower beam outer "T"

chord repair is installed, whichever

comes first.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a lower beam outer "T"

chord repair installed

on the aft end of the

lower cross beam in

accordance with Revision 6 or 7 of this

service bulletin and

the door flight cycles

are known.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

35 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 3: Supplemental Structural Inspections for Airplanes with a Preventive Modification Installed per

Original Issue or Revisions 1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or Lower Beam Outer "T" Chord

Repair Installed on the Aft End of the Lower Beam per Revision 6 through Revision 7 of this Service

Bulletin or Lower Beam Outer "T" Chord Repair Installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

4,500 door

flight cycles.

Within 4,500 door flight

cycles from the date of

Revision 7 to this service bulletin.

Within 4,500 door

flight cycles after the

lower beam outer "T"

chord repair is installed.

Do a detailed inspection

and a LFEC inspection of

the cross beam for cracks

in accordance with Work

Instructions, Part VII -

Supplemental Structural

Inspections.

Airplanes with a lower beam outer "T"

chord repair installed

on the aft end of the

lower cross beam in

accordance with Revision 6 or 7 of this

service bulletin and

the door flight cycles

are not known.

Contact Boeing for repair Before further flight. -

instructions and do the repair.

Crack(s) found.

Accomplish actions in ac- Before further flight. -

cordance with Tables 1

through 4 of Service Bulletin 737-52-1154, Original

Issue, Paragraph 1.E.,

Compliance.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

36 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair

on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

17,000 door

flight cycles.

Within 17,000 door

flight cycles from the

date of Revision 7 to

this service bulletin.

66,000 door flight cycles after installation of

the Lower Beam Outer

'T' Chord Repair on the

forward end of the lower cross-beam or

100,000 total door flight

cycles, whichever

comes first.

Do Open-Hole HFEC inspections of the forward

end of the lower cross

beam for cracks in accordance with Work Instructions, Part VIII - Forward

End Lower Beam Outer

'T' Chord Repair Supplemental Inspections.

Airplanes with a

Lower Beam Outer

'T' Chord Repair installed on the forward end of the

lower beam in accordance with Revision 6 of this Service Bulletin and

the door flight cycles since the repair are known.

Contact Boeing for repair Before further flight. -

instructions and do the

repair.

Crack(s) found.

Accomplish actions in Before further flight. -

accordance with Tables

1 through 4 of Service

Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

17,000 door

flight cycles.

17,000 door flight cycles from the date of

Revision 7 to this bulletin.

100,000 total door flight

cycles.

Do Open-Hole HFEC inspections of the forward

end of the lower cross

beam for cracks in accordance with Work Instructions, Part VIII - Forward

End Lower Beam Outer

'T' Chord Repair Supplemental Inspections.

Airplanes with a

Lower Beam Outer

'T' Chord Repair installed on the forward end of the

lower beam in accordance with Revision 6 of this Service Bulletin and

the door flight cycles since the repair are not known.

Contact Boeing for repair Before further flight. -

instructions and do the

repair.

Crack(s) found.

Accomplish actions in Before further flight. -

accordance with Tables

1 through 4 of Service

Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

37 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair

on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

17,000 door

flight cycles.

17,000 door flight cycles from the date of Revision 7 to this bulletin.Do Open-Hole HFEC inspections of the forward

end of the lower cross

beam for cracks in accordance with Work Instructions, Part VIII - Forward

End Lower Beam Outer

'T' Chord Repair Supplemental Inspections.

Airplanes with a

Lower Beam Outer

'T' Chord Repair installed on the forward end of the

lower beam in accordance with Revision 6 of this Service Bulletin and

the total door flight

cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the

repair.

Crack(s) found.

Accomplish actions in Before further flight. -

accordance with Tables

1 through 4 of Service

Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

4,500 door

flight cycles.

Within 17,000 door

flight cycles from the

date of Revision 7 of

this Service Bulletin.

Before 56,000 total

door flight cycles.

Do a detailed inspection

of the outer skin in the

inspection area for

cracks in accordance

with Work Instructions,

Part VIII - Forward End

Lower Beam Outer 'T'

Chord Repair Supplemental Inspections.

Airplanes with a

Lower Beam Outer

"T" Chord Repair

installed on the forward end of the

lower beam in accordance with Revision 6 of this Service Bulletin and

the door flight cycles are known.

Contact Boeing for repair Before further flight. -

instructions and do the

repair.

Crack(s) found.

Accomplish actions in Before further flight. -

accordance with Tables

1 through 4 of Service

Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

Bulletin

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

38 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
Table 4: Supplemental Structural Inspections for Airplanes with a Lower Beam Outer "T" Chord Repair

on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin

Repeat Interval (Not to

Exceed)

Condition Action Compliance Time (Whichever Occurs Later)

4,500 door

flight cycles.

4,500 door flight cycles from the date of Revision 7 to this bulletin.Do a detailed inspection

of the outer skin in the

inspection area for

cracks in accordance

with Work Instructions,

Part VIII - Forward End

Lower Beam Outer 'T'

Chord Repair Supplemental Inspections.

Airplanes with a

Lower Beam Outer

"T" Chord Repair

installed on the forward end of the

lower beam in accordance with Revision 6 of this Service Bulletin and

the total door flight

cycles are not

known.

Contact Boeing for repair Before further flight. -

instructions and do the

repair.

Crack(s) found.

Accomplish actions in Before further flight. -

accordance with Tables

1 through 4 of Service

Bulletin 737-52-1154,

Original Issue, Paragraph 1.E., Compliance.

F. Approval

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

in this service bulletin comply with the applicable regulations and are FAA approved, as well as European

Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved

airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on

the airplane in its original Boeing delivery configuration or as modified by other approved Boeing

changes.

If an airplane has a non-Boeing modification or repair that affects a component or system also affected

by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval

before incorporating this service bulletin.

In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the modification

defined in Revision 3, 4, 5, 6 and 7 of Service Bulletin 737-52A1079, Door - Aft Cargo, Frame and

Beam Inspection, Repair and Modification as an alternative method of compliance to the requirements

of paragraph (a) of AD 90-06-02 , amendment 39-6489. This alternative method of compliance applies

only to the modification specified in Boeing document D6-38505 for Service Bulletin 737-52A1079.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

39 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
For airplanes identified in this service bulletin, Revision 7, the repairs and/or modifications of this service

bulletin have been reviewed as required by paragraphs (g) and (i) of Airworthiness Directive AD

2008-08-23, paragraphs (g), (h) and (i) of AD 98-11-04 R1, and paragraphs (g) and (i) of AD 2008-09-13.

The repairs and/or modifications are found to affect Structurally Significant Item (SSI) F-1 of

Supplemental Structural Inspection Documents (SSID) D6-37089, Revisions D and E, and D6-82669,

but the F-1 inspections remain effective with the repairs and/or modifications installed. Therefore, an

alternative inspection is not necessary for F-1. Do the existing F-1 inspections as required per paragraphs

(g), (h) and (i) of AD 2008-08-23, paragraphs (b) and (c) of AD 98-11-04 R1, and paragraphs (g), (h),

and (i) of AD 2008-09-13.

The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the supplemental

inspections defined in paragraph 1.E, Compliance, Tables 3 and 4 of Revision 7 of this service bulletin

as an alternative method of compliance (AMOC) to the inspections of SSI F-1 required by paragraphs

(g) and (h) of AD 2008-08-23 (SSID D6-37089, Revision E), and paragraphs (g) and (h) of AD 2008-09-13

(SSID D6-82669). The Manager of the FAA Seattle ACO also approves the supplemental inspections

defined in paragraph 1.E, Compliance, Tables 3 and 4 of Revision 7 of this service bulletin as a method

of compliance to paragraph (g) of AD 98-11-04 R1 (SSID D6-37089, Revision E). This approval applies

only to SSI F-1 of the applicable SSID and only for the portions of the upper and lower cross beams

of the aft door that have been repaired and/or modified in accordance with this service bulletin. All

provisions of AD 2008-08-23, AD 98-11-04 R1, and AD 2008-09-13 that are not specifically referenced

in this paragraph remain fully applicable and must be satisfied.

In addition, the Manager of the FAA Seattle ACO approves the inspection, repair and modification with

the corresponding compliance times specified in Tables 1 and 2 of paragraph 1.E, Compliance, of this

service bulletin as an AMOC to the inspections, repairs, and modifications required by paragraphs (a),

(c), (d) and (e) of AD 2000-06-13 R1. This AMOC only applies to areas inspected, repaired or modified

by this service bulletin. All provisions of AD 2000-06-13 R1 that are not specifically referenced in this

paragraph remain fully applicable and must be satisfied.

When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions

must be approved by the FAA in accordance with paragraph (i) of AD 98-11-04 R1, paragraph (l) of

AD 2008-08-23, paragraph (l) of AD 2008-09-13, or paragraph (f) of AD 2000-06-13 R1, as applicable.

G. Manpower

Approximately 180 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.

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

Access 2 6 3

Inspection 2 20 10

Modification 2 144 72

Restoration 2 10 5

TOTAL FOR EACH AIRPLANE 180 90

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

40 of 103

BOEING SERVICE BULLETIN 737-52A1079

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

Add 24 man-hours and 12 hours downtime to the total modification for each lower

frame that requires replacement.

For airplane doors with retrofit angles 65C25180-9, -43, -10, -11 or -12: Approximately 116 man hours

and a crew of 2 men are required to accomplish this upper corner reinforcement angle inspection and

replacement.

Part VII - Supplemental Structural Inspections

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

Inspection 1 12 12

TOTAL FOR EACH AIRPLANE 12 12

H. Weight and Balance Changes

Change in Moment

(Pound-Inches)

Change in Weight

(Pounds)

Applicability

Modification

- Corner straps and beam doublers + 6.15 + 5,319.70

Repair

- Lower and/or upper beam web repair No Change No Change

- Lower beam "T" chord repair No Change No Change

I. Electrical Load Data

Not changed.

J. References

1. Existing Data:

a. Engineering Change Memo PRR 33098.

b. 737-100/200 Aircraft Maintenance Manual (AMM) 52-09-121, 52-31-0.

c. 737-100/200 Structural Repair Manual (SRM) 51-10-2 .

d. 737 Non-Destructive Testing (NDT) Manual Part 4, 52-10-02 , Part 6, 51-00-00 , Part 6,

52-30-01 .

e. Standard Overhaul Practices Manual (SOPM) 20-41-02 , 20-43-03 .

f. Overhaul Manual (OHM) 52-36-12.

g. 737 Structural Item Interim Advisory (SIIA) 737-71.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

41 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
h. Boeing Service Bulletin 737-52-1051 , 737-52-1063 , 737-52-1065 , 737-52-1154 , 737-52A1153

.

i. Boeing Document D6-38505 Structural Modification Program - Model 737-100/-200/-200C.

j. Boeing Service Related Problem (SRP) 737-SRP-52-0077 .

k. Federal Aviation Administration (FAA) Airworthiness Directive 2000-06-13 R1, 2008-08-23 ,

2008-09-13 , 90-06-02 , 98-11-04 R1, 98-25-06 .

l. Boeing Document D6-82669 Supplemental Structural Inspection Document Model

737-300/400/500 Airplanes, Original Release.

m. Boeing Document D6-37089 Supplemental Structural Inspection Document Model

737-100/200/200C Airplanes, Revisions E and D.

n. Boeing Drawing 65C25180.

2. Data supplied with this Service Bulletin:

a. Drawings:

Drawing No Title Sheet DCN/REV ADCN

Frame and Beam Reinforcement Repair - 1 C -

Aft Cargo Door

65C25180

2 D -

3 B 3

4 B 4

5 A -

6 B 3

PL G -

3. Installation Drawings Used in the Preparation of this Service Bulletin:

Drawing Number Title

65-47952 Door Assy - Aft Cargo

This drawing was used to prepare this service bulletin. This drawing is not necessary to make the

specified changes, and is not supplied with this service bulletin. This drawing may not be applicable

to all airplane configurations or operators.

4. Process Data:

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

since these procedures are frequently used as standard shop practices.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

42 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
K. Publications Affected

1. Publications

Publication Chapter-Section

737 Structural Repair Manual 52-30-2

Overhaul Manual OHM 52-36-12

2. Damage Tolerance Based Structural Inspections:

Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue

Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the

Maintenance Program. This service bulletin affects FCS and new DTI requirements for the structure

affected are contained in Paragraph 1.E., Compliance of this service bulletin.

L. Interchangeability and Intermixability of Parts

Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability

information.

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

43 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: December 16, 1983

Revision 7: December 17, 2010 737-52A1079

44 of 103

BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT

BLANK PAGE
2. MATERIAL INFORMATION

A. Material - Price and Availability

Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane, and Paragraph

2.D., Parts Necessary to Change Spares, as shown below. Kit availability is shown in the Reorder Lead

Time (ROLT). ROLT is calculated from the date Boeing gets the purchase order. 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.

Unit Price thru Sept.

30, 1996

ROLT

(weeks)

Kit Number Name

65-91434-3 Modification Kit Inactive for procurement

65-91434-4 Modification Kit 29 $ 4,530.00

65-91434-5 Supplemental Kit 26 $ 286.00

65C25180-5 Repair Kit 22 $ 737.00

65C25180-6 Repair Kit 24 $ 973.00

65C25180-7 Repair Kit 22 $ 764.00

65C25180-8 Repair Kit 23 $ 967.00

65C25180-45 Angle 33 $ 174.00

65C25180-46 Reinforcement Kit Inactive for procurement

65C25180-47 Reinforcement Kit 29 $ 2,768.00

The prices quoted are subject to the terms and condition of Boeing's standard purchase order

acknowledgment. Quotations are subject to acceptance within 180 days from date hereon. 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.

B. Industry Support Information

This service bulletin was first released before October of 1994. Thus industry support for affected

airplanes depends upon whether you ever filled a warranty claim with Boeing on this service bulletin.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
C. Parts Necessary For Each Airplane

1. Kits/Parts:

To get the kits shown below, refer to Paragraph 2.A., Material - Price and Availability.

NOTE: Modification top kit is divided into subkits for convenience of installation. Only

one top kit and the items shown in Paragraph 2.C.2., Parts and Materials

Supplied by the Operator, are necessary to modify each airplane.

1.

2. An applicable forward and aft frame repair kit should be available during door

modification.

65-91434 AFT CARGO DOOR MODIFICATION TOP KIT

-5 -4 -3 -2 -1 -

Quantity Part Number Name

. . . . - 65-91434-1 (a) Modification Top Kit

. . . - . 65-91434-2 (a) Modification Top Kit

. . - . . 65-91434-3 (b) Modification Top Kit

. - . . . 65-91434-4 (c) Modification Top Kit

- . . . . 65-91434-5 (d) Modification Suppl Kit

. . . . 1 65C25180-3 Corner Reinforcement Kit

. 1 1 1 1 65C25180-4 Lower Beam Reinforcement Kit

. 1 1 1 1 65C25180-42 Upper Beam Reinforcement Kit

. . . 1 . 65C25180-44 Corner Reinforcement Kit

. . 1 . . 65C25180-46 Corner Reinforcement Kit

. 1 . . . 65C25180-47 Corner Reinforcement Kit

1 . . . . 65C25180-51 Corner Reinforcement Suppl Kit

(a) Inactive for procurement. Rework 65-91434-1 or 65-91434-2 by reworking subkit 65C25180-

3 or 65C25180-44 to subkit 65C25180-47.

(b) Inactive for procurement. Replaced by 65-91434-4.

(c) Preferred Modification Top Kit. Replaces 65-91434-3.

(d) Supplemental Kit. 65-91434-5 plus 65-91434-3 is equivalent to 65-91434-4.

65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

Corner Reinforcement

Kit

. . . . . . - 65C25180-3 (a) -

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

Lower Beam Reinforcement Kit. . . . . - . 65C25180-4 -

Upper Beam Reinforcement Kit. . . . - . . 65C25180-42 -

Corner Reinforcement

Kit

. . . - . . . 65C25180-44 (a) -

Corner Reinforcement

Kit

. . - . . . . 65C25180-46 (b) -

Corner Reinforcement

Kit

. - . . . . . 65C25180-47 (c) -

Supplemental Kit, Corner Reinforcement- . . . . . . 65C25180-51 (d) -

. . 1 1 . . 1 65C25180-10 (e) - Angle Strap-Lwr Fwd

. . 1 1 . . 1 65C25180-11 (f) - Angle Strap-Lwr Aft

. . 1 1 . . 1 65C25180-12 (g) - Angle Strap-Upr Aft

. 1 1 1 . . 1 65C25180-13 - Seal Retainer

. 1 1 1 . . 1 65C25180-14 - Seal Retainer

. 1 1 1 . . 1 65C25180-15 - Seal Retainer

. 1 1 1 . . 1 65C25180-16 - Seal Retainer

. 1 1 1 . . 1 65C25180-17 - Filler

. 1 1 1 . . 1 65C25180-18 - Filler

. 1 1 1 . . 1 65C25180-19 - Filler

. 1 1 1 . . 1 65C25180-20 - Filler

. . . . . 1 . 65C25180-25 - Web

. . . . . 1 . 65C25180-26 - Web

. . . . . 1 . 65C25180-27 - Filler

. . . . . 1 . 65C25180-28 - Filler

. . . . . 1 . 65C25180-29 - Radius Strap

. . . . . 1 . 65C25180-30 - Radius Strap

. . . . 1 . . 65C25180-33 - Web

. . . . 1 . . 65C25180-34 - Angle

. . . 1 . . 65C25180-35 - Filler

. . . . 1 . . 65C25180-36 - Radius Strap

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

. . . . 1 . . 65C25180-38 - Web

. . . . 1 . . 65C25180-40 - Filler

. . . . 1 . . 65C25180-41 - Radius Strap

. . . 1 . . . 65C25180-43 - Angle Strap-Upr Fwd

. . 1 . . . . 65C25180-45 (i) - Angle Strap-Upr Fwd

. . . . . . . 65C25180-48 (i) - Angle Strap-Lwr Fwd

. . . . . . . 65C25180-49 (i) - Angle Strap-Lwr Aft

. . . . . . . 65C25180-50 (i) - Angle Strap-Upr Aft

. 1 . . . . . 65C25180-52 (i) 65C25180-9 (j) Angle Strap-Upr Fwd

65C25180-43 (j)

1 1 . . . . . 65C25180-53 (e) (i) 65C25180-10 (j) Angle Strap-Lwr Fwd

1 1 . . . . . 65C25180-54 (f) (i) 65C25180-11 (j) Angle Strap-Lwr Aft

1 1 . . . . . 65C25180-55 (g) (i) 65C25180-12 (j) Angle Strap-Upr Aft

. . . . . . 1 65C25180-9 - Angle Strap-Upr Fwd

. 10 10 10 . . 10 66-2955-10 - Washer

. . . . 1 . . 69-43929-4 - Bracket

. . . . 1 . . 69-43929-5 - Bracket

. 101 101 101 . . 101 BACB30FM6-3 - Hi-Lok Csk 100 Deg

. 113 113 113 . . 113 BACB30FN6A3 - Hi Lok-Csk 100 Deg

. 25 25 25 . . 25 BACB30FN6A4 - Hi Lok-Csk 100 Deg

. . . . 4 4 . BACB30FP8-6 - Hi-Lok,Shear

. . . . 8 8 . BACB30FP8-7 - Hi-Lok,Shear

. . . . 8 8 . BACB30FP8-8 - Hi-Lok,Shear

. 4 4 4 . . 4 BACB30FQ6A5 - Hi Lok-Csk 100 Deg

. 1 1 1 . . 1 BACB30KF6-3 - Hi-Lok Csk 100 Deg

. 9 9 9 . . 9 BACB30KF6-5 - Hi-Lok Csk 100 Deg

. 18 18 18 . . 18 BACB30KF6A5 - Hi Lok-Csk 100 Deg

. . . . 2 2 . BACB30KF6A6 - Hi-Lok Shear

. 4 4 4 . . 4 BACB30KF6A7 - Hi Lok-Csk 100 Deg

. 9 9 9 . . 9 BACB30KK6-3 - Hi-Lok Csk 100 Deg

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

. 8 8 8 . . 8 BACB30KK6-4 - Hi-Lok Csk 100 Deg

. 3 3 3 . . 3 BACB30KK6-6 - Hi-Lok Csk 100 Deg

. . . . . 23 . BACB30VH06-02S - Bolt-Blind

. . . . 14 . . BACB30VH06-03S - Bolt-Blind

. . . . 13 8 . BACB30VH06-04S - Bolt-Blind

. . . . 14 2 . BACB30VH06-05S - Bolt-Blind

. . . . 7 . . BACB30VH06-06S - Bolt-Blind

. 20 20 20 20 20 20 BACC30AG8 - Collar

. 243 243 243 . . 243 BACC30M6 - Collar

. 52 52 52 . . 52 BACC30R6 - Collar

. 15 15 15 . . 15 BACF3T01A11-16 - Filler-Tapered

. 2 2 2 . . 2 BACF3T01A11-9 - Filler-Tapered

. 1 1 1 . . 1 BACF3T01A12-9 - Filler-Tapered

. 2 2 2 . . 2 BACF3T01A13-16 - Filler-Tapered

. 2 2 2 . . 2 BACF3T01A13-8 - Filler-Tapered

. . . . 7 . . BACR15AD7D7 - Rivet

. 6 6 6 2 . 6 BACR15BB5D5 - Rivet

. . . . 32 53 . BACR15BB6D5 - Rivet

. . . . 55 41 . BACR15BB6D6 - Rivet

. . . . 77 106 . BACR15BB6D7 - Rivet

. . . . 4 . . BACR15BB6D8 - Rivet

. . . . 2 2 . BACR15BB8D8 - Rivet

. . . . 30 . . BACR15CE3D5 - Rivet

. . . . 2 . . BACR15CE3D7 - Rivet

. . . . 2 . . BACR15CE5D7 - Rivet

. . . . 6 . . BACR15CE6D4 - Rivet

. . . . 4 . . BACR15CE6D5 - Rivet

. 73 73 73 20 . 73 BACR15CE6D6 - Rivet-Csk 100 Deg

. 24 24 24 5 . 24 BACR15CE6D7 - Rivet-Csk 100 Deg

. 2 2 2 . 23 2 BACR15CE6D8 - Rivet-Csk 100 Deg

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

. . . . 22 . . BACR15CE6D9 - Rivet

. 2 2 2 . . 2 BACR15DS7D6 - Rivet-Csk 100 Deg

. 6 6 6 . . 6 BACR15DS7D7 - Rivet-Csk 100 Deg

. 28 28 28 . . 28 BACR15DS7D8 - Rivet-Csk 100 Deg

. . . . 8 . . BACR15ET7D10 - Rivet

. . . . . 15 . BACR15ET7D5 - Rivet

. . . . 41 9 . BACR15ET7D6 - Rivet

. . . . 102 49 . BACR15ET7D7 - Rivet

. . . . 46 2 . BACR15ET7D8 - Rivet

. . . . 13 2 . BACR15ET7D9 - Rivet

. . . . . 6 . MS90354-0602 - Rivet-Blind

Bolt-Blind (OPTIONAL

BACB30VH06-02S)

. . . . . 23 . 0SBPT6-2 (h) -

Bolt-Blind (OPTIONAL

BACB30VH06-03S)

. . . . 14 . . 0SBPT6-3 (h) -

Bolt-Blind (OPTIONAL

BACB30VH06-04S)

. . . . 13 8 . 0SBPT6-4 (h) -

Bolt-Blind (OPTIONAL

BACB30VH06-05S)

. . . . 14 2 . 0SBPT6-5 (h) -

Bolt-Blind (OPTIONAL

BACB30VH06-06S)

. . . . 7 . . 0SBPT6-6 (h) -

. . . . 1 . . 0SB100T6-3 - Bolt-Blind

(a) Inactive for procurement. Rework 65C25180-3 or 65C25180-44 to 65C25180-47 by replacing angle

65C25180-9 or 65C25180-43 with 65C25180-52 and by replacing angle 65C25180-10, -11 and -12 with

65C25180-53, -54 and -55, respectively.

(b) Inactive for procurement. Rework 65C25180-46 to 65C25180-47 by replacing angles 65C25180-10, -11

and -12 with 65C25180-53, -54 and -55, respectively.

(c) 65C25180-47 replaces 65C25180-46.

(d) 65C25180-51 plus 65C25180-46 is equivalent to 65C25180-47.

(e) 65C25180-10 is replaced by 65C25180-53.

(f) 65C25180-11 is replaced by 65C25180-54.

(g) 65C25180-12 is replaced by 65C25180-55.

(h) Huck Manufacturing Company (V17446), 900 Watson Center Road, Carson, CA 90745.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-51 -47 -46 -44 -42 -4 -3

Existing Part Name

Number

Quantity New Part Number

(i) 65C25180-45 is superseded by 65C25180-52, 65C25180-48 is superseded by 65C25180-53, 65C25180-

49 is superseded by 65C25180-54, 65C25180-50 is superseded by 65C25180-55.

(j) You can use the existing part to replace the new or changed part. If you use the existing part, you cancel

the effect of the change given in this service bulletin.

65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-8 -7 -6 -5

Quantity Part Number Name

. . . - 65C25180-5 (a) Subkit, Frame Instl-Lwr Fwd

. . - . 65C25180-6 (a) Subkit, Frame Instl-Lwr Aft

. - . . 65C25180-7 (b) Subkit, Frame Instl-Lwr Fwd

- . . . 65C25180-8 (b) Subkit, Frame Instl-Lwr Aft

. . . 1 65C25180-21 Frame-Lwr Fwd

. 1 . . 65C25180-22 Frame-Lwr Fwd

. . 1 . 65C25180-23 Frame-Lwr Aft

1 . . . 65C25180-24 Frame-Lwr Aft

3 3 3 3 AN960-416 Washer

. 4 . 4 AN960PD10L Washer

2 2 2 2 AN960PD416L Washer

3 3 3 3 BACB30FP6-3 Hi-Lok

6 6 6 6 BACB30FP6-4 Hi-Lok

. 1 . 1 BACB30LK3-4X Bolt

. 1 . 1 BACB30LU3-5X Bolt-Csk 100 Deg

8 6 8 6 BACB30VH06-04S Bolt-Blind

3 4 3 4 BACB30VH06-05S Bolt-Blind

2 . 2 . BACB30VH06-06S Bolt-Blind

4 . 4 . BACB30VH06-07S Bolt-Blind

9 9 9 9 BACC30AG6 Collar

5 7 5 7 BACN10JR3F Nut Plate

. 2 . 2 BACN10KB3F Nutplate

1 5 1 5 BACR15BB5D5 Rivet

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
65C25180 FRAME AND BEAM REINFORCEMENT/REPAIR - AFT CARGO DOOR (SUB KIT)

-8 -7 -6 -5

Quantity Part Number Name

4 4 4 4 BACR15BB6D6 Rivet

4 4 4 4 BACR15CE6D6 Rivet-Csk 100 Deg

. 8 . 8 BACR15DS7D6 Rivet-Csk 100 Deg

8 7 8 7 BACR15DS7D7 Rivet-Csk 100 Deg

4 4 4 4 BACR15ET7D10 Rivet

6 8 6 8 BACR15ET7D6 Rivet

23 9 23 9 BACR15ET7D7 Rivet

12 8 12 8 BACR15ET7D8 Rivet

2 3 2 3 BACR15ET7D9 Rivet

1 1 1 1 BACS40R06C30 Shim

. 2 . 2 MS21042L3 Nut

5 5 5 5 MS21042L4 Nut

. 2 . 2 NAS623-3-4 Screw

2 2 2 2 NAS6604-10X Bolt

3 3 3 3 NAS6604-4X Bolt

8 6 8 6 0SBPT6-4 (c) Bolt-Blind (OPTIONAL BACB30VH06-04S)

3 4 3 4 0SBPT6-5 (c) Bolt-Blind (OPTIONAL BACB30VH06-05S)

2 . 2 . 0SBPT6-6 (c) Bolt-Blind (OPTIONAL BACB30VH06-06S)

4 . 4 . 0SBPT6-7 (c) Bolt-Blind (OPTIONAL BACB30VH06-07S)

(a) Applicable for Group 1 airplanes.

(b) Applicable for Group 2 airplanes.

(c) Huck Manufacturing Company (V17446), 900 Watson Center Road, Carson, CA 90745.

2. Parts and Materials Supplied by the Operator:

INSPECTION AND MODIFICATION SUPPLIES

Quantity Specification Name

As Required BMS 5-95, Class B Sealant

As Required BMS 5-125, Type 1 (a) Leveling Compound

As Required BMS 5-92, Type 3 Bonding Compound

(a) Epibond 1542 A/B, M&T Chemicals (V99384), Furane Products Division, 5121 San

Fernando Road West, Los Angeles, CA 90039.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
REPAIR PARTS - LOWER BEAM FORWARD END (FIG 4)

Quantity Specification Name

1 0.056 x 1.9 x 10.9, clad 7075-T6 or 2024-T3 Filler A

Make from BAC1512-3355 x 0.65 wide x 11.0 long, 7075- Radius Filler A

T6511 or 2024-T3511

1

Make from BAC1512-3355 x 0.60 wide x 6.5 long, 7075- Radius Filler B

T6511 or 2024-T3511

1

Make from BAC1512-3355 x 0.65 wide x 0.90 long, 7075- Radius Filler C

T6511 or 2024-T3511

2

1 1.55 x 8.30 x 0.040, 2024-0 Angle A

1 1.44 x 6.40 x 0.050, 2024-0 Angle B

1 BAC1505-100570 x 8.0, 2024-0 (a) Replacement 'T' Chord A

1 4.83 x 11.67 x 0.071, 7075-0 Doubler

8 BACR15BB7D9 Rivet

2 MS20470D6-7. Optional: BACR15BB6D7 Rivet

2 BACR15CE6D6. Optional: BACR15GF6D6 Rivet

13 BACR15CE6D8. Optional: BACR15GF6D8 Rivet

7 BACR15CE6D9. Optional: BACR15GF6D9 Rivet

As Required (Alodine 1200S) MIL-C-5541 Chemical Film Treatment

As Required BMS 10-11, Type 1 Primer

(a) As an option to joggling the 2024-0 extrusion and heat-treating in accordance with Figure 4, replacement

'T' chord A can be made from part 65C80735-25 by trimming part to length.

REPAIR PARTS - LOWER BEAM AFT END (FIG 6) (a)

Quantity Specification Name

Make from BAC1512-3355 x 0.60 wide x 6.50 long, 7075- Radius Filler B

T6511 or 2024-T3511

1

Make from BAC1512-3355 x 0.65 wide x 0.90 long, 7075- Radius Filler C

T6511 or 2024-T3511

2

1 1.55 x 8.50 x 0.040, 2024-0 Angle C

1 1.44 x 6.50 x 0.050, 2024-0 Angle D

1 BAC1505-100570 x 9.0, 2024-0 (b) Replacement 'T' Chord B

8 BACR15BB7D9 Rivet

3 BACR15CE6D6. Optional: BACR15GF6D6 Rivet

2 BACR15CE6D8. Optional: BACR15GF6D8 Rivet

7 BACR15CE6D9. Optional: BACR15GF6D9 Rivet

BOEING PROPRIETARY -

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
REPAIR PARTS - LOWER BEAM AFT END (FIG 6) (a)

Quantity Specification Name

As Required (Alodine 1200S) MIL-C-5541 Chemical Film Treatment

As Required BMS 10-11, Type 1 Primer

(a) In addition to the parts shown below, you will need doubler 65C25180-25, filler 65C25180-27, and radius

strap 65C25180-30. These parts are contained in subkit 65C25180-4.

(b) As an option to joggling the 2024-0 extrusion and heat-treating in accordance with Figure 6, replacement

'T' chord B can be made from part 65C80735-25 by trimming part to length.

3. Parts Modified and Reidentified:

The parts shown below are changed in accordance with this service bulletin. The quantity (QTY)

is the number of parts changed on each airplane.

Existing Part QTY Name New Part Number Notes

Number

65-47952-1 1 Door Assembly - (a) (b) (c)

65-47952-524 1 Door Assembly - (a) (b) (c)

(a) Make the change in accordance with this service bulletin.

(b) There is no equivalent Boeing part number for the changed part. Identify on

the part that the change in accordance with this service bulletin was made.

(c) You can use the existing part to replace the new or changed part. If you use

the existing part, you cancel the effect of the change given in this service

bulletin.

4. Parts Removed and Not Replaced:

None.

D. Parts Necessary to Change Spares

To get the kits shown below, refer to Paragraph 2.A., Material - Price and Availability.

Quantity Part Number Name

1 65-91434-4 Modification Top Kit

E. Special Tooling - Price and Availability

The operator can supply the tools shown in Paragraph 2.F., Special Tooling Necessary to do this

Service Bulletin. Tool price and supply data are not given.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
F. Special Tooling Necessary to do this Service Bulletin

To get the tools shown below, refer to Paragraph 2.E., Special Tooling - Price and Availability.

Maintenance and overhaul tools in the manuals shown in Paragraph 1.J., References, can also be

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

Tool Kit Number Name Notes

SUS 1015-10MHz-70A Transducer (a) (c)

HS-7520-10-70A Transducer (b) (c)

(a) Available from: NDT Engineering Corporation (Cage Code 61100) 19620 Russell

Road Kent, WA 98032-1115

(b) Available from: Staveley Sensors Inc. (Cage Code 59334) 91 Prestige Park Circle

East Hartford, CT 06108-1918

(c) A different vendor can make the transducer. But it must have the properties specified

below, that the transducer: - Puts a shear wave in aluminum that is between 65 and 75

degrees. - Operates at a frequency of between 9 MHz and 11 MHz. - Has a maximum

outer case length of 0.315 inches (8.0 mm). - Can give satisfactory results during calibration

as specified in 737 NDT Manual, Part 4, 52-10-02.

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ALERT ALERT
BOEING PROPRIETARY -

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT

BLANK PAGE
3. ACCOMPLISHMENT INSTRUCTIONS

A. GENERAL INFORMATION

CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL

PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL,

METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE

DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR

OTHER ELECTRICAL DAMAGE.

NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for

definition of the acronyms.

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

3. Unless shown differently, these dimensions and tolerances are used:

— Linear dimensions are in inches

— Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus

or minus 0.03 inch.

— Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch

— Angular tolerance is plus or minus 2 degrees

— For hole dimensions for standard solid rivets, refer to 737 Structural Repair

Manual, Chapter 51

— For torque limits to tighten nuts and bolts, refer to 737 Structural Repair Manual,

Chapter 51.

— Shim all gaps greater than 0.005 inch.

4. For approved fastener and process material substitutions, refer to 737 Structural

Repair Manual, Chapter 51. For alternate fasteners, refer to 737 Structural Repair

Manual Chapter 51.

5. If the length of fasteners specified in this service bulletin do not meet the installation

standards, fasteners of the same specification, or an approved substitute, one grip

length longer or shorter may be used.

6. As recommended by the 737 Aging Fleet Structures Working Group, accomplish the

modification in accordance with this service bulletin, Part II, prior to, or upon the

accumulation of 75,000 flight cycles as required by AD 90-06-02.

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BOEING SERVICE BULLETIN 737-52A1079

ALERT ALERT
7. A Detailed Inspection is defined as: An intensive examination of a specific item,

installation, or assembly to detect damage, failure, or irregularity. Available lighting

is normally supplemented with a direct source of good lighting at an intensity deemed

appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be

necessary. Surface cleaning and elaborate procedures may be required.

8. A General Visual Inspection is defined as: A visual examination of an interior or

exterior area, installation or assembly to detect obvious damage, failure or irregularity.

This level of inspection is made from within touching distance unless otherwise

specified. A mirror may be necessary to ensure visual access to all surfaces in the

inspection area. This level of inspection is made under normal available lighting

conditions such as daylight, hangar lighting, flashlight or drop-light and may require

removal or opening of access panels or doors. Stands, ladders or platforms may be

required to gain proximity to the area being checked.

9. These work instructions refer to procedures included on other Boeing documents.

When the words "refer to" are used and the operator has an accepted alternative

procedure, the accepted alternative procedure can be used. When the words "in

accordance with" are included in the instruction, the procedure in the Boeing document

must be used.

B. WORK INSTRUCTIONS

GROUP 1 AND 2 AIRPLANES

1. PART I - Access

NOTE:

If you previously installed reinforcement angles 65C25180-9 or -43 (upper

forward), -10 (lower forward), -11 (lower aft) or -12 (upper aft), in accordance

with the original issue, Revision 1, 2, 3, or 4 of this service bulletin, then do Part

V - 'Corner Inspection and Rework'.

1.

2. The following instructions supplement information contained on Drawing

65C25180. Unless otherwise noted all references herein are to that drawing.

a. Remove or push aside the insulation in the aft cargo door as required to gain access to the

inside of the four corner frames and the ends of the upper and lower cross beams.

b. Identify the aft cargo door assembly part number which is currently installed on each airplane

in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1.

If the door is found to be from an airplane in the line number greater than 873, accomplish all

applicable actions in accordance with the original issue of Boeing Service Bulletin 737-52A1153

.

c. Remove the aft cargo door. Refer to 737-100/200 AMM 52-31-0 as an accepted procedure.

d. Remove the aft cargo door flap type seal. Refer to 737-100/200 AMM 52-09-121 as an accepted

procedure.

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e. Remove and discard corner seal retainers in accordance with Sheet 2, Views 1A5-1 and 1A7-1

and Sheet 3, Views 3B5 and 3C11. Remove and retain the forward and aft seal retainers in

accordance with Sheet 2, Views 1A5-1 and 1A7-1.

f. Remove exterior skin fasteners in accordance with Sheet 1, View 3A2.

NOTE: Remove any sealant found in each frame corner radius before inspection. If cracks

do exist in this inspection area they could be hidden under the existing sealant.

g. Do Part II - Inspection.

2. PART II - Inspection

a. Remove or push aside the insulation in the aft cargo door as required to gain access to the

inside of the four corner frames and the ends of the upper and lower cross beams.

b. Identify the aft cargo door assembly part number which is currently installed on each airplane

in accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1.

If the door is found to be from an airplane in the line number greater than 873, accomplish all

applicable actions in accordance with Service Bulletin 737-52A1153 , Original Issue.

c. Do the inspection in accordance with FIGURE 1.

d. If no cracks are found, modify the door in accordance with Part III.

e. If cracks up to complete severance are found in the upper or lower beam web, repair the beam

in accordance with the beam modification in Part III. In addition, accomplish all applicable

actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified

in Paragraph 1.E., Compliance .

f. For the lower beam, if cracks are found in the web and outer "T" chord or in the outer "T"

chord only, then repair the beam in accordance with Part VI - Lower Beam Outer "T" Chord

Repair. In addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154 , Original Issue, at the time specified in Paragraph 1.E., Compliance .

g. For the upper beam, if cracks are found in the outer "T" chord, contact Boeing for repair

instructions and do the repair before further flight. In addition, accomplish all applicable actions

in accordance with Service Bulletin 737-52-1154, Original Issue, at the time specified in

Paragraph 1.E., Compliance.

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h. If cracks are found in the forward or aft upper corner frame, replace the frame and install the

preventive modification in accordance with Part III. In addition, accomplish all applicable

actions in accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified

in Paragraph 1.E., Compliance .

i. If cracks are found in the forward or aft lower door frame, replace the damaged frame in

accordance with Part IV Lower Forward and Aft Frame Replacement and modify in accordance

with Part III - Preventive Modification. In addition, accomplish all applicable actions in

accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in

Paragraph 1.E., Compliance .

j. Put the airplane back to a serviceable condition.

3. PART III - Preventive Modification

NOTE: The following instructions supplement information contained on Drawing 65C25180.

Unless otherwise noted all references herein are to that drawing.

a. Gain access to the lower beam by removing the door inner skin in accordance with Sheet 1,

View 1A2. Retain removed parts for reinstallation.

b. Gain access to the upper beam by removing the door inner skin in accordance with Sheet 5,

View 4A2-1. Retain removed parts for reinstallation.

c. If cracks are found during inspection of the lower and upper cross beams, trim out the web

cracks with a 0.40 minimum trim radius. Do a HFEC surface inspection within 0.20 of the edge

of the trim out. If cracks are found, trim them out and repeat the HFEC surface inspection.

When no cracks are found, make a 0.20 insurance cut to the edge of the trim out. Maintain

0.38 minimum edge margins. Replace trim out with a 7075-T6 aluminum filler. Finish filler with

one coat of chemical conversion coating (Alodine 1200S, Type II), refer to SOPM 20-43-03

and one coat of primer (BMS 10-11, Type I), refer to SOPM 20-41-02 . Do the Preventive

Modification to the upper and lower cross beams in accordance with paragraphs d and e. In

addition, accomplish all applicable actions in accordance with Service Bulletin 737-52-1154

, Original Issue, at the time specified in Paragraph 1.E., Compliance .

d. Use Kit 65C25180-4 and modify the lower cross beam in accordance with Sheet 2, Views

B1-1 and B3-1.

e. Use Kit 65C25180-42 and modify the upper cross beam in accordance with Sheets 5 and 6.

f. Use Kit 65C25180-47 and locate and drill corner reinforcement angles and seal retainers in

accordance with Sheet 1, View 3A2; Sheet 2, Views 1A5-1 and 1A7-1; and Sheet 3, Views

3B5 and 3C11.

NOTE: Trim corner strap angles on installation as required to fit door stops, latch torque

tube housing and water drain seal retainer in accordance with Sheet 2, View 1A5-1

and 1A7-1.

g. Remove seal retainers and trim ends in accordance with Sheet 1, View C8. Apply chemical

film treatment (Alodine or Iridite, Refer to 737-100/200 SRM 51-10-2 as an accepted procedure)

and one coat of epoxy primer (Ref. BMS 10-11, Type 1).

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h. Remove corner reinforcement angles and install repair washers in accordance with Flag Note

14 on Sheet 2, Views 1A5-1 and 1A7-1.

i. Install corner reinforcement angles and seal retainer with faying surface sealant (Ref. BMS

5-95, Class B) between all surfaces.

j. Reapply all fillet seals that were disturbed during modification using sealant (Ref. BMS 5-95,

Class B).

k. Position door as if it was installed on the airplane with door closed and airplane level. Apply

leveling compound (Ref. BMS 5-125, Type 1) level with bottom of drain hole in accordance

with Sheet 1, View 2A5, see Flag Note 10.

l. Reinstall inner skins in accordance with Sheet 1, View 1A2 and Sheet 5.

m. Install the flap type seal. Refer to 737-100/200 AMM 52-09-121 as an accepted procedure.

n. Install the door. Refer to 737-100/200 AMM 52-31-0 as an accepted procedure. Use the

procedure for installing a new door.

o. Put the airplane back to a serviceable condition.

p. Do Part VII - Supplemental Structural Inspections at the times given in Paragraph 1.E.,

Compliance .

4. PART IV - Lower Frame Replacement for Aft and Forward Frames.

NOTE: The following instructions supplement information contained on Drawing 65C25180.

Unless otherwise noted all references herein are to that drawing.

a. Remove inner skin fasteners for frame removal as required in accordance with Sheet 4, View

2A2-1.

b. Remove and retain the lower seal retainer in accordance with Sheet 4, View 1B4.

c. Remove and retain roller arm. Refer to OHM 52-36-12 as an accepted procedure.

d. For aft frame replacement remove and retain housing assembly, reinforcement plate, channel

assembly and bracket in accordance with Sheet 4, View D2. Remove remaining attachment

fasteners and remove frame.

e. For forward frame replacement remove and retain housing assembly, reinforcement plate,

channel assembly, guide assembly, pulley bracket, radius fillers and latch channel in

accordance with Sheet 4, View D4. Remove remaining attachment fasteners and remove

frame.

f. For aft frame installation use Kit 65C25180-6 for Group 1 airplanes or 65C25180-8 for Group

2 airplanes. Locate frame in accordance with Sheet 4, View D2.

g. For forward frame installation use Kit 65C25180-5 for Group 1 airplanes or 65C25180-7 for

Group 2 airplanes. Locate frame in accordance with Sheet 4, View D4.

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h. Drill frame to match existing hole locations. Locate components removed in Paragraph d or

e above and drill frame to match existing hole locations.

NOTE: The hole pattern from old frame may be used as an aid to locate components on

new frame.

i. Accomplish Part III, Paragraph f and g.

j. Reinstall applicable frame components in accordance with Paragraph d or e, plus the

reinforcement angles and seal retainers in accordance with Paragraph i, with faying surface

sealant (Ref. BMS 5-95, Class B) between all surfaces.

k. Install inner and outer skin fasteners.

l. Reinstall roller arm removed in Paragraph c. Refer to OHM 52-36-12 as an accepted procedure.

m. Reapply all fillet seals that were disturbed during frame replacement using sealant (Ref. BMS

5-95, Class B).

n. Install the flap type seal. Refer to 737-100/200 AMM 52-09-121 as an accepted procedure.

o. Install the door. Refer to 737-100/200 AMM 52-31-0 as an accepted procedure. Use the

procedure for installing a new door.

p. Put the airplane back to a serviceable condition.

5. PART V - Corner Inspection and Rework.

a. On airplanes with repair angles 65C25180-9, -43, -10, -11 or -12 installed, open the aft cargo

door and inspect the upper forward, upper aft, lower aft and lower forward corners. Inspect

for tabs, correct edge margin and cracks in each corner reinforcement angle in accordance

with FIGURE 2 .

b. If the edge margin is less than the noted dimension or cracks are found, replace the corner

reinforcement angles. If no cracks are found and edge margin is adequate, no more work is

necessary.

c. Put the airplane back to a serviceable condition.

6. PART VI - Lower Beam Outer "T" Chord Repair.

a. Gain access to the lower beam by removing the door inner skin in accordance with View 1A2

of Sheet 1.

b. If cracks are found during inspection of the lower beam, trim out the web cracks with a 0.40

minimum trim radius. Do a HFEC surface inspection within 0.20 of the edge of the trim out. If

cracks are found, trim them out and repeat the HFEC surface inspection. When no cracks are

found, make a 0.20 insurance cut to the edge of the trim out. Maintain 0.38 minimum edge

margins. Replace trim out with a 7075-T6 aluminum filler. Finish filler with one coat of chemical

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conversion coating (Alodine 1200S, Type II), refer to SOPM 20-43-03 and one coat of primer

(BMS 10-11, Type I), refer to SOPM 20-41-02 . Do the Repair to the lower cross beam in

accordance with paragraphs c and d. In addition, accomplish all applicable actions in

accordance with Service Bulletin 737-52-1154 , Original Issue, at the time specified in

Paragraph 1.E., Compliance .

c. To repair the forward end of the beam, do the repair in accordance with FIGURE 3. Make the

necessary repair parts in accordance with FIGURE 4.

d. To repair the aft end of the beam, do the repair in accordance with FIGURE 5. Make the

necessary repair parts in accordance with FIGURE 6.

e. Reinstall lower inner skin in accordance with View 1A2 of Sheet 1.

f. Install the flap type seal. Refer to 737-100/200 AMM 52-09-121 as an accepted procedure.

g. Install the cargo door. Refer to 737-100/200 AMM 52-31-0 as an accepted procedure. Use

the procedure for installing a new door.

h. Put the airplane back to a serviceable condition.

i. Do Part VII - Supplemental Structural Inspections at the times given in Paragraph 1.E.,

Compliance .

7. PART VII - Supplemental Structural Inspections.

a. Airplanes with a Part III - Preventive Modification installed per the original issue or Revisions

1, 2, 3, 4, 5, 6 or 7 of this Service Bulletin or a Part VI - Lower Beam Outer "T" Chord Repair

installed on the Aft End of the Lower Beam per Revision 6 through 7 of this Service Bulletin

or Lower Beam Outer "T" Chord Repair installed on the Forward End of the Lower Beam per

this Revision of this Service Bulletin.

(1) Do detailed and LFEC inspections of the forward end of the aft cargo door lower cross

beam for cracks in accordance with FIGURE 7 at the times shown in Paragraph 1.E.,

Compliance.

(a) If any crack is found, contact Boeing for repair instructions and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

(2) Do detailed and LFEC inspections of the aft end of the aft cargo door lower cross beam

for cracks in accordance with FIGURE 8 at the times shown in Paragraph 1.E.,

Compliance.

(a) If any crack is found, contact Boeing for repair instructions and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

(3) Do detailed and LFEC inspections of the forward end of the aft cargo door upper cross

beam for cracks in accordance with FIGURE 9 at the times shown in Paragraph 1.E.,

Compliance.

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(a) If any crack is found, contact Boeing for repair instructions and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

(4) Do detailed and LFEC inspections of the aft end of the aft cargo door upper cross beam

for cracks in accordance with FIGURE 10 at the times shown in Paragraph 1.E.,

Compliance.

(a) If any crack is found, contact Boeing for repair instructions and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

b. Put the airplane back to a serviceable condition.

8. PART VIII - Supplemental Structural Inspections for a Part VI - Lower Beam Outer "T" Chord Repair

installed on the Forward End of the Lower Beam per Revision 6 of this Service Bulletin.

a. Verify that a Lower Beam Outer "T" Chord Repair has been accomplished on the forward end

of the lower beam in accordance with Revision 6 of this Service Bulletin.

NOTE: Beams with the Outer "T" Chord Repair will have two repair angles installed common

to the Outer "T" Chord, next to the Stop Fitting.

(1) If a Lower Beam Outer "T" Chord Repair has been accomplished on the forward end of

the lower beam in accordance with Revision 6 of this Service Bulletin, do an Open-Hole

HFEC inspections of the forward end of the aft cargo door lower cross beam for cracks

in accordance with FIGURE 11 at the times shown in Paragraph 1.E., Compliance.

(a) If any crack is found, contact Boeing for repair instruction and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

(2) If a Lower Beam Outer "T" Chord Repair has been accomplished on the forward end of

the lower beam in accordance with Revision 6 of this Service Bulletin, do a detailed

inspection of the outer skin in the inspection area for cracks in accordance with FIGURE

11 at the times shown in Paragraph 1.E., Compliance.

(a) If any crack is found, contact Boeing for repair instruction and do the repair. In

addition, accomplish all applicable actions in accordance with Service Bulletin

737-52-1154, Original Issue, at the time specified in Paragraph 1.E., Compliance.

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ALERT ALERT
GROUP 3 AIRPLANES

1. Remove or push aside the insulation in the aft cargo door as required to gain access to the inside

of the four corner frames and one end of the lower cross beam.

2. Identify the aft cargo door assembly part number which is currently installed on each airplane in

accordance with Boeing Service Bulletin 737-52A1153 , Original Issue, Paragraph 3.B.1. If the

door is found to be from an airplane in the line number range greater than 873, accomplish all

applicable actions in accordance with the original issue of Boeing Service Bulletin 737-52A1153

.

3. If the door is found to be from an airplane in the line number range between 6 and 873, accomplish

all applicable actions in accordance with Revision 7 of this service bulletin.

4. Put the airplane back to a serviceable condition.

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ALERT ALERT
FIGURE 1: AFT CARGO DOOR INSPECTION

(SHEET 1 OF 4)

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FIGURE 1: AFT CARGO DOOR INSPECTION

(SHEET 2 OF 4)

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

STEP TASK NAME PROCEDURE REFERENCES MORE DATA

1 Remove Outer Skin - - (a)

Get Access Cross Beams - - (b)

Adjacent to the beam

and stop fitting.

2 Remove Seal Retainer - -

Related to the stop fitting and frame.Fasteners - -

Related to the stop fitting and cross beam.Fasteners - -

From the door and

move to get access for

inspection of the Tchord radius. (f)

Detach Stop Fitting - -

Inspect for cracks in the

fastener holes.

In accordance with 737

NDT Part 6, 51-00-00 Figure 1, 11 or 16.

HFEC (High Frequency Eddy

Current)

3 Inspect Beam Web

T-chord Flange

Inspect for cracks in the

fastener holes.

In accordance with 737

NDT Part 6, 51-00-00 Figure 1, 11 or 16.

4 Inspect Beam Web HFEC

Beam Inner

Chord

In accordance with 737 (c)

NDT Part 6, 51-00-00 Figure 4 or 23.

5 Inspect Beam Web HFEC

In accordance with 737 (d)

NDT Part 6, 51-00-00 Figure 4 or 23.

6 Inspect T-chord Flange HFEC

In accordance with 737 (d)

NDT Part 6, 51-00-00 Figure 4 or 23.

Beam Inner HFEC

Chord

7 Inspect

Inspect the radius surface on both sides for

cracks.

In accordance with 737

NDT Part 6, 51-00-00 Figure 4 or 23.

8 Inspect T-chord Radius HFEC

In accordance with 737 (e)

NDT Part 4, 52-10-02.

9 Inspect Frame Ultrasonic

(a) Detach the outer skin to allow for the installation of the corner reinforcement angle in accordance with

FIGURE 2, Detail I.

(b) Get access to the cross beams to allow for the installation of the repair in accordance with FIGURE 3 and

FIGURE 5.

FIGURE 1: AFT CARGO DOOR INSPECTION

(SHEET 3 OF 4)

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ALERT ALERT
STEP TASK NAME PROCEDURE REFERENCES MORE DATA

(c) Inspect the surface for cracks around each hole within 0.2 inches and within 0.2 inches from the edge of

the stop fitting.

(d) Inspect the surface for cracks around each hole within 0.2 inches.

(e) Locally detach the pressure seal adjacent to the corner stop and detach the seal retainer corner segment.

(f) It is possible that the stop fitting cannot be fully removed because there is not sufficient clearance with

the adjacent structure. If this is the condition, it is satisfactory to detach the stop fitting.

FIGURE 1: AFT CARGO DOOR INSPECTION

(SHEET 4 OF 4)

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FIGURE 2: CORNER INSPECTION AND REWORK

(SHEET 1 OF 2)

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

STEP TASK NAME PROCEDURE REFERENCES NOTES

1 Inspect Edge margin General visual - (a)

Inspect on both sides of door stop fittings for tabs above the seal retainer.Corner Rein- General visual -

forcement Angle

2 Inspect

NOTE: If inspection reveals satisfactory edge margin, no further action is required.

This step is only necessary if the corner reinforcement angle tabs on either

side of the door stop fittings are not

visible.

Seal and Seal - -

Retainer

Remove/

Keep

3

If edge margin is less than noted dimension, do a detailed inspection for

cracks in edge of angle. (a)

4 Inspect Edge Margin General visual -

Seal and Seal - - Use BACB30FM6-3 bolts.

Retainer

Install/

Kept

5

(a) If the edge margin is less than the noted dimension or cracks are found, replace the angle in accordance

with Part III. If edge margin is adequate and no cracks are found, no more work is necessary on the

corner reinforcement angles in accordance with this service bulletin.

FIGURE 2: CORNER INSPECTION AND REWORK

(SHEET 2 OF 2)

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ALERT ALERT
FIGURE 3: LOWER BEAM REPAIR - FORWARD END

(SHEET 1 OF 5)

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ALERT ALERT
FIGURE 3: LOWER BEAM REPAIR - FORWARD END

(SHEET 2 OF 5)

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FIGURE 3: LOWER BEAM REPAIR - FORWARD END

(SHEET 3 OF 5)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME SPECIFICATION QTY NOTES

Existing "T" - 1 (a)

Chord

Trim and

Remove

1

Remove Tapered Filler BACF3T01A11-16 1 -

/Keep

2

0.056 x 1.9 x 10.9, clad 7075-T6 or

2024-T3.

3 Make Filler A - 1

Filler B - 1 BAC1512-3370 x 9.8 long, 7075-T6.

0.060 thick tapering to 0.01 thick x

0.72 wide x 0.36 long, clad 7075-T6.

Tapered Filler - 1

Make from BAC1512-3355 x 0.65

wide x 11.0 long, 7075-T6511 or

2024-T3511.

Radius Filler A - 1

Make from BAC1512-3355 x 0.6 wide

x 6.5 long, 7075-T6511 or 2024-

T3511.

Radius Filler B - 1

Make from BAC1512-3355 x 0.65

wide x 0.90 long, 7075-T6511 or

2024-T3511.

Radius Filler C - 2

(Alodine 1200S) 1 layer (b)

MIL-C-5541

Chemical Film

Treatment

4 Apply

Primer BMS 10-11, Type 1 1 layer (c)

5 Install Tapered Filler BACF3T01A11-16 1 Kept from Step 2.

Make in accordance with FIGURE 4

or make from 65C80735-25 by trimming to length.

Replacement - 1

"T" Chord A

Filler A - 1 -

Doubler - 1 Make in accordance with FIGURE 4.

Filler B - 1 -

Tapered Filler - 1 -

Radius Filler A - 1 -

Angle A - 1 Make in accordance with FIGURE 4.

Angle B - 1 Make in accordance with FIGURE 4.

Radius Filler B - 1 -

Radius Filler C - 2 -

FIGURE 3: LOWER BEAM REPAIR - FORWARD END

(SHEET 4 OF 5)

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STEP TASK NAME SPECIFICATION QTY NOTES

(a) Trim the chord at the location shown in View A-A. Maintain an edge margin of at least 0.38 inches

on both flanges of the "T" chord.

(b) Apply to the radius fillers and the trimmed edges of the fillers and the existing "T" chord as necessary.

(c) Apply to the fillers, radius fillers and trimmed edge of the "T" chord.

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.

A number in the lower right corner gives the grip length of the fastener.

CODE NAME IDENTIFICATION HOLE DIA MORE DATA

Use existing hole in "T" chord or web to

locate the hole.

0.221 - 0.233

(#2 drill bit)

A Rivet BACR15BB7D9

New hole. Locate approximately in accordance with View A-A. Locate 0.8 to 1.2

inch from other fasteners and 0.38 inch

minimum from the edge of Filler A.

0.191 - 0.202

(#10 drill bit)

B Rivet MS20470D6-7

BACR15BB6D7 optional to MS20470D6-

7.

0.191 - 0.202

(#10 drill bit)

OPTIONAL:

BACR15BB6D7

Use existing hole in skin to locate hole.

100 degree countersink.

0.190 - 0.198

(#10 drill bit)

C Rivet BACR15CE6D( )

BACR15GF6D( ) optional to

BACR15CE6D( ).

0.190 - 0.198

(#10 drill bit)

OPTIONAL:

BACR15GF6D( )

FIGURE 3: LOWER BEAM REPAIR - FORWARD END

(SHEET 5 OF 5)

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FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END

(SHEET 1 OF 5)

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FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END

(SHEET 2 OF 5)

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FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END

(SHEET 3 OF 5)

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Doubler A - Flat Pattern Coordinates

Location X Coordinate Y Coordinate

1 0 0

2 0.12 0.78

3 -0.72 0.60

4 -1.26 2.78

5 -0.29 2.98

6 -0.67 3.48

7 -0.67 4.62

8 9.61 4.62

9 9.98 4.40

10 10.41 4.00

11 10.09 4.00

12 9.83 0

R1 0.16

R2 0.31

R3 0.43

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME PART NUMBER QTY NOTES

Cut the angle to shape out of 0.040 thick

clad 2024-0 sheet.

1 Cut Out Angle A - 1

Cut the angle to shape out of 0.050 thick

clad 2024-0 sheet.

Angle B - 1

Bend up 90 degrees. Bend to 0.12R. Heat

treat to T42.

2 Bend Up Angle A - -

Bend up 90 degrees. Bend to 0.12R. Heat

treat to T42.

Angle B - -

Make from extrusion BAC1505-100570,

2024-T0. Joggle as shown. Make the cuts

125 microinches Ra. Heat treat to T42

condition. (a)

Replacement "T" - 1

Chord A

3 Make

Trim the end of the replacement 'T' chord

as necessary to fit the existing trimmed 'T'

chord. Make the cut 125 microinches Ra.

Replacement "T" - -

Chord A

4 Trim

FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END

(SHEET 4 OF 5)

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STEP TASK NAME PART NUMBER QTY NOTES

Cut the doubler to shape out of 0.071 thick

clad 7075-0 sheet.

5 Cut Out Doubler - 1

Bend the doubler up 90 degrees on two

flanges and 45 degrees on the other. Bend

to 0.12R. Heat treat to T62.

6 Bend Up Doubler - -

Trim the doubler in accordance with View

A-A. Make the cut 125 microinches Ra.

7 Trim Doubler - -

Apply to replacement 'T' chord A and the

cut edges of doubler A, Angle A, and Angle

B.

1 Layer(Alodine 1200S)

MIL-C-5541

Chemical Film

Treatment

8 Apply

Apply to doubler, Angle A, Angle B, and

replacement 'T' chord A.

1 LayerBMS 10-11,

Type 1

Primer

(a) This step is not necessary if the replacement "T" chord is made from part number 65C80735-25.

FIGURE 4: REPAIR PARTS - LOWER BEAM FORWARD END

(SHEET 5 OF 5)

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FIGURE 5: LOWER BEAM REPAIR - AFT END

(SHEET 1 OF 5)

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FIGURE 5: LOWER BEAM REPAIR - AFT END

(SHEET 2 OF 5)

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FIGURE 5: LOWER BEAM REPAIR - AFT END

(SHEET 3 OF 5)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

Trim the chord at the location shown in

View A-A. Maintain an edge margin of at

least 0.38 inches.

Existing "T" - 1

Chord

Trim and

Remove

1

Re- Tapered Filler BACF3T01A11-16 1 -

move/Keep

2

Make from BAC1512-3355 x 0.60 wide

x 6.5 long, 7075-T6511 or 2024-T3511.

3 Make Radius Filler B - 1

Make from BAC1512-3355 x 0.65 wide

x 0.90 long, 7075-T6511 or 2024-T3511.

Radius Filler C - 2

Apply to radius fillers B and C and to the

cut edge of the 'T' chord.

(Alodine 1200S) 1 layer

MIL-C-5541

Chemical Film

Treatment

4 Apply

Apply to radius fillers B and C and to the

cut edge of the 'T' chord.

Primer BMS 10-11, Type 1 1 layer

5 Install Tapered Filler BACF3T01A11-16 1 Kept from Step 2.

Make in accordance with Figure 6 or

make from part 65C80735-25 by trimming

part to length as necessary.

Replacement - 1

"T" Chord B

Filler 65C25180-27 1 Contained in subkit 65C25180-4.

Doubler 65C25180-25 1 Contained in subkit 65C25180-4.

Radius Strap 65C25180-30 1 Contained in subkit 65C25180-4.

Angle C - 1 Make in accordance with FIGURE 6.

Angle D - 1 Make in accordance with FIGURE 6.

Radius Filler B - 1 -

Radius Filler C - 2 -

The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.

A number in the lower right corner gives the grip length of the fastener.

CODE NAME IDENTIFICATION HOLE DIA MORE DATA

Use existing hole in "T" chord to

locate the hole.

0.221 - 0.233 (#2

drill bit)

A Rivet BACR15BB7D9

B Not used - - -

FIGURE 5: LOWER BEAM REPAIR - AFT END

(SHEET 4 OF 5)

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CODE NAME IDENTIFICATION HOLE DIA MORE DATA

Use existing hole in skin to locate

hole. 100 degree countersink.

0.190 - 0.198 (#10

drill bit)

C Rivet BACR15CE6D( )

BACR15GF6D( ) optional to

BACR15CE6D( )

0.190 - 0.198 (#10

drill bit)

OPTIONAL:

BACR15GF6D( )

FIGURE 5: LOWER BEAM REPAIR - AFT END

(SHEET 5 OF 5)

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FIGURE 6: REPAIR PARTS - LOWER BEAM AFT END

(SHEET 1 OF 2)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME PART NUMBER QTY NOTES

Cut the angle to shape out of 0.040 thick

clad 2024-0 sheet.

1 Make Angle C - 1

Cut the angle to shape out of 0.050 thick

clad 2024-0 sheet.

Angle D - 1

Bend it up 90 degrees x 0.12R. Heat treat

to T42.

2 Bend Up Angle C - -

Bend it up 90 degrees x 0.12R. Heat treat

to T42.

Angle D - -

Make from extrusion BAC1505-100570,

2024-0. Joggle as shown. Make cuts 125

microinches Ra. Heat treat to T42 condition.

(a)

Replacement "T" - 1

Chord B

3 Make

Trim the end of replacement "T" chord B

as necessary to fit the existing trimmed 'T'

chord. Make the cut 125 microinches Ra.

Replacement "T" - -

Chord B

4 Trim

Apply to the replacement "T" chord B and

the cut edges of Angle C and Angle D.

(Alodine 1200S) 1 Layer

MIL-C-5541

Chemical Film

Treatment

5 Apply

Apply to Angle C, Angle D, and replacement "T" chord B.BMS 10-11, Type 1 Layer

1

Primer

(a) This step can be skipped if you make the replacement 'T' chord from part 65C80735-25.

FIGURE 6: REPAIR PARTS - LOWER BEAM AFT END

(SHEET 2 OF 2)

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FIGURE 7: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 1 OF 3)

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FIGURE 7: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 2 OF 3)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

All Visible Struc- - - (a)

ture

1 Inspect

2 Inspect Cross Beam - - (b)

(a) Do a Detailed Inspection of all visible structure from both sides of the beam. NOTE: Get access

through the lightening holes on the inner skin and access covers on the outer skin as necessary.

(b) Do a Low Frequency Eddy Current (LFEC) inspection of the cross beam through the outer skin as

necessary for cracks in accordance with 737 NDT Part 6, 52-30-01.

FIGURE 7: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 3 OF 3)

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FIGURE 8: AFT CARGO DOOR - LOWER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 1 OF 3)

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FIGURE 8: AFT CARGO DOOR - LOWER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 2 OF 3)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

All Visible Struc- - - (a)

ture

1 Inspect

2 Inspect Cross Beam - - (b)

(a) Do a Detailed Inspection of all visible structure from both sides of the beam. NOTE: Get access through

the lightening holes on the inner skin and access covers on the outer skin as necessary.

(b) Do a Low Frequency Eddy Current (LFEC) inspection of the cross beam through the outer skin as

necessary for cracks in accordance with 737 NDT Part 6, 52-30-01.

FIGURE 8: AFT CARGO DOOR - LOWER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 3 OF 3)

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FIGURE 9: AFT CARGO DOOR - UPPER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 1 OF 3)

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FIGURE 9: AFT CARGO DOOR - UPPER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 2 OF 3)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

All Visible Struc- - - (a)

ture

1 Inspect

2 Inspect Cross Beam - - (b)

(a) Do a Detailed Inspection of all visible structure from both sides of the beam. NOTE: Get access through

the lightening holes on the inner skin and access covers on the outer skin as necessary.

(b) Do a Low Frequency Eddy Current (LFEC) inspection of the cross beam through the outer skin as

necessary for cracks in accordance with 737 NDT Part 6, 52-30-01.

FIGURE 9: AFT CARGO DOOR - UPPER CROSS BEAM - FORWARD END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 3 OF 3)

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FIGURE 10: AFT CARGO DOOR - UPPER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 1 OF 3)

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FIGURE 10: AFT CARGO DOOR - UPPER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 2 OF 3)

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

numbers shown below are the number of parts necessary for this Figure.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

All Visible Struc- - - (a)

ture

1 Inspect

2 Inspect Cross Beam - - (b)

(a) Do a Detailed Inspection of all visible structure from both sides of the beam. NOTE: Get access through

the lightening holes on the inner skin and access covers on the outer skin as necessary.

(b) Do a Low Frequency Eddy Current (LFEC) inspection of the cross beam through the outer skin as

necessary for cracks in accordance with 737 NDT Part 6, 52-30-01.

FIGURE 10: AFT CARGO DOOR - UPPER CROSS BEAM - AFT END - SUPPLEMENTAL STRUCTURAL

INSPECTION

(SHEET 3 OF 3)

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FIGURE 11: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION FOR AIRPLANES WITH LOWER BEAM OUTER 'T' CHORD REPAIR INSTALLED

ON THE FORWARD END

(SHEET 1 OF 3)

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FIGURE 11: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION FOR AIRPLANES WITH LOWER BEAM OUTER 'T' CHORD REPAIR INSTALLED

ON THE FORWARD END

(SHEET 2 OF 3)

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

numbers shown below are the number of parts necessary for this Figure.

Lower Cross Beam Open-Hole HFEC Inspection

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Fasteners - - (a)

2 Inspect Cross Beam - - (b)

Replacement Fas- - - (c)

teners

3 Install

(a) Remove fasteners in the web flange of Outer T-Chord in the inspection area. Be careful when removing

fasteners, it will not be possible to oversize the holes.

(b) Do an Open-Hole HFEC inspection of the fastener holes in the inspection area for cracks. Refer to

737 NDT Part 6, 51-00-00 Figure 1, 11 or 16 as an accepted procedure.

(c) Install fasteners same type and size as those removed. Oversizing of fastener holes is not allowed.

Outer Skin Detailed Inspection

STEP TASK NAME IDENTIFICATION QTY MORE DATA

4 Inspect Outer Skin - - (d)

(d) Do a detailed inspection of the outer skin in the inspection area.

FIGURE 11: AFT CARGO DOOR - LOWER CROSS BEAM - FORWARD END - SUPPLEMENTAL

STRUCTURAL INSPECTION FOR AIRPLANES WITH LOWER BEAM OUTER 'T' CHORD REPAIR INSTALLED

ON THE FORWARD END

(SHEET 3 OF 3)

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