Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-52A2294

Original Issue: July 08, 2010

Revision 1: August 16, 2011

ATA System: 5232

SUBJECT: DOORS - Side Cargo Doors - Main Deck Side Cargo Door Latch Pin and Latch Pin

Retention Bolt Inspection and Modification

Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15

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persons from specific countries. The controller of this data has the individual responsibility to abide by all export

laws.

ECCN: 9E991

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Copyright © 2010 The Boeing Company

Unpublished Work - All Rights Reserved

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5.0
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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT

BLANK PAGE
Table of Contents

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

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

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

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

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

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

1. Existing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2. Data supplied with this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3. Installation Drawings Used in the Preparation of this Service Bulletin . . . . . . . . . . . . 31

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2. Parts and Materials Supplied by the Operator . . . . . . . . . . . . . . . . . . . . . . . . 35

3. Parts Modified and Reidentified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 37

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

FIGURE 1: DETAILED INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

FIGURE 2: TORQUE CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

FIGURE 3: LATCH PIN POSITION CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

FIGURE 4: PART REPLACEMENT AT LATCH PIN FITTING POSITIONS #1, #3, #7, #8, #9 AND #10 . 54

FIGURE 5: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2 [Group 1-2, Configuration 2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

FIGURE 6: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2 [Group 1-2, Configuration 1;

Group 3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

FIGURE 7: PART REPLACEMENT AT LATCH PIN FITTING POSITION #4 . . . . . . . . . . . . . . 63

FIGURE 8: PART REPLACEMENT AT LATCH PIN FITTING POSITION #5 . . . . . . . . . . . . . . 66

FIGURE 9: PART REPLACEMENT AT LATCH PIN FITTING POSITION #6 . . . . . . . . . . . . . . 69

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
FIGURE 10: MODIFICATION AT LATCH PIN FITTING POSITION #1, #3, #7, #8, #9 AND #10 . . . . 72

FIGURE 11: MODIFICATION AT LATCH PIN FITTING POSITION #4 . . . . . . . . . . . . . . . . . . 76

FIGURE 12: MODIFICATION AT LATCH PIN FITTING POSITION #5 . . . . . . . . . . . . . . . . . . 80

FIGURE 13: MODIFICATION AT LATCH PIN FITTING POSITION #6 . . . . . . . . . . . . . . . . . . 84

FIGURE 14: MODIFICATION AT LATCH PIN FITTING POSITION #2 [Group 1-2, Configuration 2] . . 88

FIGURE 15: MODIFICATION AT LATCH PIN FITTING POSITION #2 [Group 1-2, Configuration 1; Group 3]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

FIGURE 16: LATCH PIN REWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Commercial 

Airplanes 747

Service Bulletin

ALERT

Revision Transmittal Sheet Number: 747-52A2294

Original Issue: July 08, 2010

Revision 1: August 16, 2011

ATA System: 5232

SUBJECT: DOORS - Side Cargo Doors - Main Deck Side Cargo Door Latch Pin and Latch Pin

Retention Bolt Inspection and Modification

This revision includes all pages of the service bulletin.

COMPLIANCE INFORMATION RELATED TO THIS REVISION

More work is necessary on the airplane(s) inspected in accordance with the original issue of this service bulletin.

Repeat the latch pin retention bolt inspections at the time given in this service bulletin. In addition, at the time

given in this service bulletin, Boeing recommends that the 3/16 inch diameter latch pin retention bolts be replaced

with 5/16 inch diameter pin retention hardware in accordance with Revision 1.

No airplanes were added to the service bulletin effectivity.

REASON FOR REVISION

This revision is sent to change the one-time inspection given in the original issue of this service bulletin into

repeat inspections. Also, instructions for replacement of the 3/16 inch diameter latch pin retention bolts with

5/16 inch diameter pin retention hardware has been added. This replacement includes modification of the latch

pin fittings and installation of new latch pins. New Figures 10 through 15 have been added.

In addition, this revision identifies another possible configuration for Group 1 and Group 2 airplanes. If the

modification given in Boeing Service Bulletin 747-52-2224 was installed, the configuration of the latch pin

installation at pin fitting position #4 will be different, and similar to position #4 on Group 3 airplanes.

The data given in Information Notice 747-52A2294 IN 01 is included in this revision. IN 01 was sent to clarify

that in Figures 4, 5, 7, 8 and 9 it is acceptable to install an additional washer under the nut if necessary for

fastener grip length adjustment.

These sections have changed:

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1. On the Summary page, the "Action" section was changed to show that the detailed inspections should be

repeated, and to include the retention bolt modification.

2. The illustration on the Summary page was changed to include the retention bolt modification.

3. The Group/Configuration table in Paragraph 1.A.1., Airplanes, was changed to include Configurations 1

and 2 for Groups 1 and 2. These configurations are dependent whether the modification given in Boeing

Service Bulletin 747-52-2224, "Doors - Cargo Doors - Door Warning - Forward and Aft Lower Lobe and

Main Deck Side Cargo Door Warning System Revision" has been installed. The modification changes the

latch pin and retention bolt configuration at latch pin fitting #2.

4. Paragraph 1.B., Concurrent Requirements was changed to include Boeing Service Bulletin 747-52-2258.

5. Paragraph 1.D., Description was changed to show that the detailed inspections should be repeated, and

to include the retention bolt modification.

6. In Paragraph 1.E., Compliance, Table 1 was changed to include repeat inspections, and to include the

retention bolt modification as an alternative to inspection. Table 2 was added to give Compliance information

for the retention bolt modification. Table 3 was added to include the repeated inspections necessary after

the retention bolt modification has been accomplished.

7. In Paragraph 1.G., Manpower, a title was added to the original man-hour table. Tables 2 and 3 were added

for the retention bolt modification and the after-modification inspections.

8. Items were added to Paragraph 1.J.1., Existing Data.

9. Tool Drawing MIT140U8005 was added to Paragraph 1.J.2., Data supplied with this Service Bulletin.

10. In Paragraph 1.K.2., Damage Tolerance Based Structural Inspections:, the paragraph was changed to

indicate that DTIs are included in Paragraph 1.E., Compliance.

11. Paragraph 2.A., Material - Price and Availability and Paragraph 2.C., Parts Necessary for Each Airplane

were changed to include Modification Top Kit 015U1916-1.

12. Paragraph 2.C.3., Parts Modified and Reidentified, was changed to include latch pins that can be reworked.

13. Paragraph 2.E., Special Tooling - Price and Availability and Paragraph 2.F., Special Tooling Necessary to

do this Service Bulletin were changed to include the MIT140U8005-1 tool kit necessary for the retention

bolt modification.

14. In Paragraph 3.A., General Information, additional general notes have been included.

15. In Paragraph 3.B., Work Instructions, PART 4 was changed to describe the proper figure for latch pin fitting

position #2 for the different Configurations of Group 1 and Group 2. PART 5 was changed to specify repeat

inspections. PART 6, describing the retention bolt modification was added. PART 7, describing the

after-modification inspections, was added.

16. Figures 10 - 15 have been added to show details of the latch pin retention bolt modification. Figure 16 was

added to show an optional rework for certain latch pin part numbers.

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 747-52A2294

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

REVISION HISTORY

Original Issue: July 08, 2010

Revision 1: August 16, 2011

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Summary Number: 747-52A2294

Original Issue: July 08, 2010

Revision 1: August 16, 2011

ATA System: 5232

SUBJECT: DOORS - Side Cargo Doors - Main Deck Side Cargo Door Latch Pin and Latch Pin

Retention Bolt Inspection 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

Refer to Paragraph 1.B., Concurrent Requirements.

BACKGROUND

Accomplishment of the inspections in this service bulletin will ensure that the latch pin retention bolts in the Main

Deck Side Cargo Door lower sill latch pin fittings are not loose, broken or missing. A loose, broken or missing

retention bolt can result in a migrated latch pin, which can become disengaged from the cargo door latch cams,

and lead to increased loads in the adjacent latch pin fittings and latch cams. Increased loads can cause damage

to the cargo door latch mechanism and/or the lower sill structure. The migration of two or more latch pins and

subsequent failure of the latch mechanism or lower sill structure can result in the inability of the cargo door to

carry limit loads, which could lead to the loss of the cargo door and depressurization of the airplane.

The Main Deck Side Cargo Door has a series of ten latch pin fittings which are attached to the lower sill of the

door cutout and numbered 1 through 10 forward to aft. Latch pins are installed in each latch pin fitting, and each

is secured with a retention bolt. The latch pins and latch pin fittings carry structural and pressurization loads

during flight.

Six operators have reported that broken latch pin retention bolts were found on eight airplanes. On one airplane,

with 101,609 flight-hours and 12,862 flight-cycles, the retention bolts on both the #9 and #10 latch pin fittings

were found to be broken. Latch pin #10 was found to have migrated aft and was not engaging the latch cam.

On another airplane, with 33,983 flight-hours and 4,723 flight-cycles, the retention bolt on the #10 latch pin fitting

was found to be broken and the #9 latch pin was found to be damaged. On another airplane with 67,188

flight-hours and 14,440 flight-cycles, the retention bolt for the #10 latch pin fitting was found to be completely

sheared, which allowed the latch pin to migrate aft until it no longer engaged the door latch cam. On four airplanes,

only the retention bolt on the #10 latch pin fitting was found to be broken. On one airplane the retention bolt on

the #10 latch pin fitting was found to be damaged.

Boeing Service Related Problem (SRP) 747-SRP-52-0093 is related to this service bulletin.

Boeing Fleet Team Digest article 747-FTD-52-09002 is related to this service bulletin.

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ACTION (PRR 85901-112RS)

Get access to the lower sill of the Main Deck Side Cargo Door (MDSCD) cutout. Do a Detailed Inspection of all

ten latch pin fittings for loose, broken or missing retention bolts and nuts. Measure the latch pins to make sure

they are within allowable limits.

At any latch pin fitting that does not have a loose, broken or missing retention bolt and nut, and the latch pin is

not damaged beyond the limits given in this service bulletin, remove sealant and do a torque check in accordance

with this service bulletin. If the retention bolt passes the torque check, replace the retention bolt sealant. If the

retention bolt fails the torque check, consider the bolt to be broken.

At any latch pin location where the retention bolt and nut was not found to be broken, loose, damaged or missing,

but the latch pin is damaged beyond the limits given in this service bulletin, replace the latch pin, the retention

bolt, and related parts in accordance with this service bulletin.

At any latch pin fitting with a loose, broken or missing retention bolt or nut, do a check for latch pin migration in

accordance with this service bulletin. If the latch pin has not migrated, replace parts at the affected latch pin

fitting location in accordance with this service bulletin. If the latch pin has migrated, do additional Detailed

Inspections of adjacent door and door cutout structure and latch cams within 42 inches of the affected fitting for

damage in accordance with this service bulletin. Repair any damage that is found. Replace parts at the affected

latch pin fitting location and any adjacent latch pin fitting location in accordance with this service bulletin.

The inspection is complete when the retention bolts at all ten latch pin fitting locations have either passed the

torque check or been replaced in accordance with this service bulletin or other Boeing instructions, and all ten

MDSCD latch pins are within the damage limits given in this service bulletin. Do the inspections again at the

times given in this service bulletin.

At the time given in this service bulletin, Boeing recommends that the 3/16 inch diameter latch pin retention bolts

be replaced with 5/16 inch diameter latch pin retention hardware. As part of this replacement, the retention bolt

holes in the latch pin fittings must be made larger, and new latch pins with larger diameter retention bolt holes

must be installed.

EFFECTIVITY

747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400F, and 747SR Airplanes. Refer to Paragraph

1.A.1., Airplanes, for the list of affected airplanes.

COMPLIANCE

The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service

bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin

mandatory.

Refer to Paragraph 1.E., Compliance.

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the inspections and configuration changes given in this service

bulletin.

MANPOWER

Refer to Paragraph 1.G., Manpower.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
MATERIAL INFORMATION

Boeing Supplied Kits/Parts.

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

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT

BLANK PAGE
Commercial 

Airplanes 747

Service Bulletin

ALERT

Number: 747-52A2294

Original Issue: July 08, 2010

Revision 1: August 16, 2011

ATA System: 5232

SUBJECT: DOORS - Side Cargo Doors - Main Deck Side Cargo Door Latch Pin and Latch Pin

Retention Bolt Inspection 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

Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line

Number, and Serial Number data.

This service bulletin is for the airplanes shown below.

GROUP CONFIGURATION DESCRIPTION

All 747-100, 747-200B, 747-200C, 747-200F, 747SR, 747-300,

747-400, and 747-400F airplanes with a Main Deck Side Cargo Door

(MDSCD) installed in production or by a Boeing-approved

modification, except Group 2 and Group 3 airplanes.

1 -

Previously modified in accordance with Boeing Service Bulletin

747-52-2224.

1

Not previously modified in accordance with Boeing Service Bulletin

747-52-2224, or not in the effectivity of Boeing Service Bulletin

747-52-2224.

2

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GROUP CONFIGURATION DESCRIPTION

All 747 airplanes that are listed in the effectivity of Boeing Service

Bulletin 747-52-2142.

2 -

Previously modified in accordance with Boeing Service Bulletin

747-52-2224.

1

Not previously modified in accordance with Boeing Service Bulletin

747-52-2224.

2

3 - 747-200F airplanes R6156 and R6157.

Airplane Models:

747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400F, 747SR

Variable Number Group

RA002 1

RA006 1

RA011 1

RA015 1

RA026 2

RA028 1

RA029 2

RA030 1

RA033 2

RA101 - RA103 2

RA111 1

RA112 2

RA161 - RA163 2

RA401 - RA405 1

RA524 2

RA631 1

RA632 2

RA633 1

RA634 - RA635 2

RA749 2

RA750 1

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Variable Number Group

RA784 1

RA901 - RA902 2

RA910 1

RA911 - RA913 2

RA914 1

RA915 - RA916 2

RB041 2

RB043 2

RB101 - RB102 2

RB411 - RB413 1

RB421 1

RB604 - RB605 1

RB607 1

RB696 1

RD041 - RD044 1

RD055 1

RD082 - RD083 1

RD142 1

RD144 1

RD201 - RD204 1

RD225 1

RD227 1

RD233 - RD235 1

RD301 - RD302 1

RD358 1

RD361 - RD366 1

RD411 - RD412 1

RD433 - RD434 1

RD441 - RD442 1

RD461 1

RD531 - RD533 1

RD551 1

RD561 1

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Variable Number Group

RD571 1

RD581 - RD583 1

RD591 - RD593 1

RD601 - RD602 2

RD603 - RD607 1

RD621 - RD623 2

RD641 - RD642 2

RD643 - RD649 1

RD651 2

RD652 - RD659 1

RD661 1

RD671 1

RD681 - RD682 2

RD691 - RD692 2

RD701 - RD702 1

RD721 - RD722 1

RD741 - RD742 1

RD751 - RD755 1

RD761 1

RD771 - RD775 1

RD781 - RD783 1

RD791 - RD792 1

RJ301 - RJ302 2

RJ303 1

RJ321 - RJ322 1

RJ331 - RJ333 1

RL401 - RL403 1

RL411 - RL436 1

RL451 - RL456 1

RL461 - RL462 1

RL471 - RL481 1

RL491 - RL492 1

RL501 - RL502 1

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Variable Number Group

RL511 - RL516 1

RL521 - RL522 1

RL531 - RL534 1

RL551 1

RL561 - RL568 1

RL571 - RL572 1

RL576 - RL577 1

RL579 1

RL581 - RL586 1

RL651 - RL655 1

RL671 - RL675 1

RL681 - RL684 1

RL751 - RL752 1

RM128 1

RM801 - RM803 1

RM811 - RM813 1

RM851 - RM859 1

RM861 - RM863 1

RM871 - RM899 1

RM901 - RM906 1

RM911 1

RR005 1

RR021 - RR025 1

RR031 1

RR202 - RR206 1

RR221 - RR222 2

RR223 - RR226 1

RR261 2

RR263 - RR267 1

RR301 - RR302 2

RR303 - RR309 1

RR310 3

RR331 - RR332 1

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ALERT ALERT
Variable Number Group

RR336 1

RR341 - RR344 2

RR345 1

RR361 - RR362 1

RR421 - RR422 1

RR431 - RR432 1

RR441 - RR442 1

RR451 1

RR501 - RR504 1

RR521 - RR522 1

RR526 1

RR531 1

RR551 - RR555 1

RR556 3

RR561 1

RR566 1

RR701 1

RR721 - RR724 1

RR746 - RR748 1

RR851 - RR856 1

RR861 - RR862 1

RR951 - RR952 1

RS701 - RS703 1

RS711 - RS713 1

RS721 - RS722 1

RS731 - RS732 1

RS741 - RS743 1

RS751 - RS752 1

RS761 - RS762 1

RS771 1

RS781 - RS782 1

RS786 1

RT001 - RT014 1

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ALERT ALERT
Variable Number Group

RT021 - RT022 1

RT031 - RT035 1

RT041 - RT047 1

RT061 1

RT071 - RT075 1

RT101 - RT103 1

RT121 1

RT131 - RT137 1

RT151 - RT152 1

RT161 - RT168 1

RT456 1

RT461 1

RT501 1

RT506 - RT510 1

RT513 1

RT516 1

RT518 - RT520 1

RT524 1

RT528 1

RT572 - RT576 1

RT642 1

RT655 - RT657 1

RT751 - RT752 1

RT781 - RT782 1

RT837 1

RT953 - RT954 1

RT967 1

2. Spares Affected

None.

B. Concurrent Requirements

The service bulletin listed below must be done before or at the same time as the modification given in

this service bulletin:

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Company Service Bulletin Description

Inspection for interchanged cargo door latch

pins and installation of pin stop brackets.

747-52-2142, Original issue, Dated May 6,

1977

Boeing

747-52A2258, Original issue, Dated June 1, Cargo door latch pin direction inspection.

1995

Boeing

C. Reason

Accomplishment of the inspections in this service bulletin will ensure that the latch pin retention bolts

in the Main Deck Side Cargo Door lower sill latch pin fittings are not loose, broken or missing. A loose,

broken or missing retention bolt can result in a migrated latch pin, which can become disengaged from

the cargo door latch cams, and lead to increased loads in the adjacent latch pin fittings and latch cams.

Increased loads can cause damage to the cargo door latch mechanism and/or the lower sill structure.

The migration of two or more latch pins and subsequent failure of the latch mechanism or lower sill

structure can result in the inability of the cargo door to carry limit loads, which could lead to the loss of

the cargo door and depressurization of the airplane.

The Main Deck Side Cargo Door has a series of ten latch pin fittings which are attached to the lower

sill of the door cutout and numbered 1 through 10 forward to aft. Latch pins are installed in each latch

pin fitting, and each is secured with a retention bolt. The latch pins and latch pin fittings carry structural

and pressurization loads during flight.

Six operators have reported that broken latch pin retention bolts were found on eight airplanes. On one

airplane, with 101,609 flight-hours and 12,862 flight-cycles, the retention bolts on both the #9 and #10

latch pin fittings were found to be broken. Latch pin #10 was found to have migrated aft and was not

engaging the latch cam. On another airplane, with 33,983 flight-hours and 4,723 flight-cycles, the

retention bolt on the #10 latch pin fitting was found to be broken and the #9 latch pin was found to be

damaged. On another airplane with 67,188 flight-hours and 14,440 flight-cycles, the retention bolt for

the #10 latch pin fitting was found to be completely sheared, which allowed the latch pin to migrate aft

until it no longer engaged the door latch cam. On four airplanes, only the retention bolt on the #10 latch

pin fitting was found to be broken. On one airplane the retention bolt on the #10 latch pin fitting was

found to be damaged.

Revision 1 is sent to change the one-time inspection given in the original issue of this service bulletin

into repeat inspections. Also, instructions for replacement of the 3/16 inch diameter latch pin retention

bolts with 5/16 inch diameter pin retention hardware has been added. This replacement includes

modification of the latch pin fittings and installation of new latch pins. New Figures 10 through 15 have

been added. In addition, Revision 1 identifies another possible configuration for Group 1 and Group 2

airplanes. If the modification given in 747-52-2224 was installed, the configuration of the latch pin

installation at pin fitting position #4 will be different, and similar to position #4 on Group 3 airplanes.

The data given in Information Notice 747-52A2294 IN 01 is included in Revision 1. IN 01 was sent to

clarify that in Figures 4, 5, 7, 8 and 9 it is acceptable to install an additional washer under the nut if

necessary for fastener grip length adjustment.

Boeing Service Related Problem (SRP) 747-SRP-52-0093 is related to this service bulletin.

Boeing Fleet Team Digest article 747-FTD-52-09002 is related to this service bulletin.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
D. Description

Get access to the lower sill of the Main Deck Side Cargo Door (MDSCD) cutout. Do a Detailed Inspection

of all ten latch pin fittings for loose, broken or missing retention bolts and nuts. Measure the latch pins

to make sure they are within allowable limits.

At any latch pin fitting that does not have a loose, broken or missing retention bolt and nut, and the

latch pin is not damaged beyond the limits given in this service bulletin, remove sealant and do a torque

check in accordance with this service bulletin. If the retention bolt passes the torque check, replace

the retention bolt sealant. If the retention bolt fails the torque check, consider the bolt to be broken.

At any latch pin location where the retention bolt and nut was not found to be broken, loose, damaged

or missing, but the latch pin is damaged beyond the limits given in this service bulletin, replace the

latch pin, the retention bolt, and related parts in accordance with this service bulletin.

At any latch pin fitting with a loose, broken or missing retention bolt or nut, do a check for latch pin

migration in accordance with this service bulletin. If the latch pin has not migrated, replace parts at the

affected latch pin fitting location in accordance with this service bulletin. If the latch pin has migrated,

do additional Detailed Inspections of adjacent door and door cutout structure and latch cams within 42

inches of the affected fitting for damage in accordance with this service bulletin. Repair any damage

that is found. Replace parts at the affected latch pin fitting location and any adjacent latch pin fitting

location in accordance with this service bulletin.

The inspection is complete when the retention bolts at all ten latch pin fitting locations have either

passed the torque check or been replaced in accordance with this service bulletin or other Boeing

instructions, and all ten MDSCD latch pins are within the damage limits given in this service bulletin.

Do the inspections again at the times given in this service bulletin.

At the time given in this service bulletin, Boeing recommends that the 3/16 inch diameter latch pin

retention bolts be replaced with 5/16 inch diameter pin retention hardware. As part of this replacement,

the retention bolt holes in the latch pin fittings must be made larger, and new latch pins with larger

diameter retention bolt holes must be installed.

Revision 1 - More work is necessary on airplane(s) inspected in accordance with the original issue of

this service bulletin. Repeat the latch pin retention bolt inspections at the time given in this service

bulletin. In addition, at the time given in this service bulletin, Boeing recommends that the 3/16 inch

diameter latch pin retention bolts be replaced with 5/16 inch diameter pin retention hardware in

accordance with Revision 1.

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

Group 1:

Affected Maintenance Zones

Model Zone

747-100, 747-200B, 747-200C, 261, 262

747-200F, 747-300, 747-400,

747-400F, 747SR

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Group 2:

Affected Maintenance Zones

Model Zone

747-100, 747-200B, 747-200C, 261, 262

747-200F

Group 3:

Affected Maintenance Zones

Model Zone

747-200F 261, 262

E. Compliance

The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to

this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this

service bulletin mandatory.

For airplanes that have not yet been modified in accordance with this service bulletin, Boeing

recommends that the inspections in Table 1 and the modifications in Table 2 be done at the times given

in the tables. The inspections in Table 1 are no longer necessary after the modifications in Table 2

have been completed.

After the modifications in Table 2 have been completed, do inspections in accordance with Table 3 at

the times given in Table 3.

Table 1: LATCH PIN FITTING INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 6 months -

after the original issue date of this

service bulletin.

Do a Detailed Inspection

of the ten Main Deck Side

Cargo Door (MDSCD)

latch pin retention bolts

and nuts, and measure

the latch pins in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

1.

All affected airplanes

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Table 1: LATCH PIN FITTING INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before further -

flight.

Do a torque check of the

retention bolt in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

2.

At any latch pin location

where the retention bolt

and nut was not found to

be loose, broken, damaged

or missing, and the latch

pin is not damaged beyond

the limits given in Paragraph 3.B., Work Instructions , PART 1.

No more work is neces- - -

sary at that location during this inspection interval.

At any latch pin location

where the retention bolt

torque check passed and

the latch pin is not damaged beyond the limits given in Paragraph 3.B.,

Work Instructions , PART

1.

Before further -

flight.

Consider the bolt to be

broken. Check the latch

pin for migration in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

3.

At any latch pin location

where the retention bolt

torque check failed.

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 4.

At any latch pin location

where the retention bolt

and nut was not found to

be broken, loose, damaged

or missing, but the latch pin

is damaged beyond the

limits given in Paragraph

3.B., Work Instructions ,

PART 1.

Before further -

flight.

Check the latch pin for

migration in accordance

with Paragraph 3.A.,

General Information and

Paragraph 3.B., Work Instructions, PART 3.

At any latch pin location

where the retention bolt or

nut was found to be broken, loose, damaged or

missing.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Table 1: LATCH PIN FITTING INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before further -

flight.

Do additional Detailed Inspections of adjacent

door and door cutout

structure and latch cams

within 42 inches of the

affected fitting for damage in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 3.

At any location with a broken, loose, damaged or

missing retention bolt or

nut, where the latch pin is

found to be migrated.

Before further -

flight.

Repair damage in accordance with Boeing maintenance documents

(Structural Repair Manual, Component Maintenance Manual), or ask

Boeing for repair data

and install the repair. Replace the latch pin, the

retention bolt, and related

parts at the affected latch

pin fitting and any adjacent latch pin fitting in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

3 and PART 4.

Damage found during the

Detailed Inspections of adjacent door and door cutout

structure and latch cams,

done in accordance with

Paragraph 3.B., Work Instructions, PART 3 and

PART 4.

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts at the affected latch

pin fitting and any adjacent latch pin fitting location in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 3 and PART

4.

No damage found during

the Detailed Inspections of

adjacent door and door

cutout structure and latch

cams, done in accordance

with Paragraph 3.B., Work

Instructions, PART 3 and

PART 4.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Table 1: LATCH PIN FITTING INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 4.

At any location with a broken, loose, damaged or

missing retention bolt or

nut, where the latch pin is

not found to be migrated.

Within 6 months of 6 months.

the previous inspection done in accordance with this

service bulletin.

Repeat the Detailed Inspection of the ten Main

Deck Side Cargo Door

(MDSCD) latch pin retention bolts and nuts, and

measure the latch pins in

accordance with Paragraph 3.A., General Information and Paragraph

3.B., Work Instructions ,

PART 1.

All ten MDSCD latch pin

fitting retention bolts have

either passed the torque

check or been replaced in

accordance with Paragraph

3.B., Work Instructions,

PART 4, and all ten MDSCD latch pins are within

the damage limit given in

Paragraph 3.B., Work Instructions , PART 1.

Table 2: LATCH PIN FITTING MODIFICATION AND PIN REPLACEMENT

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 48 months -

after the date on

Revision 1 of this

service bulletin.

Modify the MDSCD latch

pin fittings and replace

the latch pins and latch

pin retention fasteners in

accordance with Paragraph 3.A., General Information and Paragraph

3.B., Work Instructions,

PART 6.

All affected airplanes

Inspect in accordance - -

with Table 3.

Airplanes with the modification in accordance with

Paragraph 3.B., Work Instructions, PART 6 accomplished.

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ALERT ALERT
Table 3: AFTER-MODIFICATION INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Within 2 years after -

the modification in

accordance with

Paragraph 3.B.,

Work Instructions,

PART 6 was accomplished.

Do an Detailed Inspection

of the ten Main Deck Side

Cargo Door (MDSCD)

latch pin retention bolts

and nuts, and measure

the latch pins in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

7. (a)

All affected airplanes with

the modification in accordance with Paragraph 3.B.,

Work Instructions, PART 6

accomplished.

Repeat the Detailed In- - 2 years. (a)

spection of the latch pin

retention bolts and nuts,

and measure the latch

pins in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 7.

At any latch pin location

where the retention bolt

and nut was not found to

be broken, loose, damaged

or missing, and the latch

pin is not damaged beyond

the limits given in Paragraph 3.B., Work Instructions, PART 7.

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 7.

At any latch pin location

where the retention bolt

and nut was not found to

be broken, loose, damaged

or missing, but the latch pin

is damaged beyond the

limits given in Paragraph

3.B., Work Instructions,

PART 7.

Before further -

flight.

Check the latch pin for

migration in accordance

with Paragraph 3.A.,

General Information and

Paragraph 3.B., Work Instructions, PART 7.

At any latch pin location

where the retention bolt or

nut was found to be broken, loose, damaged or

missing.

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ALERT ALERT
Table 3: AFTER-MODIFICATION INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Before further -

flight.

Do additional Detailed Inspections of adjacent

door and door cutout

structure and latch cams

within 42 inches of the

affected fitting for damage in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 7.

At any location with a broken, loose, damaged or

missing retention bolt or

nut, where the latch pin is

found to be migrated.

Before further -

flight.

Repair the damage in accordance with Boeing

maintenance documents

(Structural Repair Manual, Component Maintenance Manual) or ask

Boeing for repair data

and install the repair. Replace the latch pin, the

retention bolt, and related

parts at the affected latch

pin fitting and any adjacent latch pin fitting in accordance with Paragraph

3.A., General Information

and Paragraph 3.B.,

Work Instructions, PART

7.

Damage found during the

Detailed Inspections of adjacent door and door cutout

structure and latch cams,

done in accordance with

Paragraph 3.B., Work Instructions, PART 7.

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts at the affected latch

pin fitting and any adjacent latch pin fitting location in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 7.

No damage found during

the Detailed Inspections of

adjacent door and door

cutout structure and latch

cams, done in accordance

with Paragraph 3.B., Work

Instructions, PART 7.

Before further -

flight.

Replace the latch pin, the

retention bolt, and related

parts in accordance with

Paragraph 3.A., General

Information and Paragraph 3.B., Work Instructions, PART 7.

At any location with a broken, loose, damaged or

missing retention bolt or

nut, where the latch pin is

not found to be migrated.

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ALERT ALERT
Table 3: AFTER-MODIFICATION INSPECTIONS

Repeat Interval

(Not to Exceed)

Condition Action Compliance Time

Repeat the Detailed In- - 2 years.

spection of the latch pin

retention bolts and nuts,

measure the latch pins,

and check for latch pin

migration in accordance

with Paragraph 3.A.,

General Information and

Paragraph 3.B., Work Instructions, PART 7.

At any latch pin location

where the latch pin, the retention bolt, or related parts

were replaced in accordance with Paragraph 3.B.,

Work Instructions, PART 7.

(a) This is expected to create an additional task card to be added to the operator's maintenance

program.

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.

G. Manpower

The table below shows an estimate of the task hours necessary to do this inspection for each airplane.

This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator

task hour data if necessary. The estimate does not include lost time. These are some examples of lost

time:

• Time to adjust to the workplace

• Time to schedule the work

• Time to inspect the work

• Time to cure the materials

• Time to make the parts

• Time to find the tools.

Table 1 - Inspection

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.10 0.10

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Table 1 - Inspection

Task Number of Persons Task Hours Elapsed Hours

Detailed Inspection 1 1.00 1.00

(Figure 1)

Torque Check (Fig- 1 2.00 2.00

ure 2)

Close Access 1 0.10 0.10

TOTAL FOR EACH AIRPLANE 3.20 3.20

NOTE: More time will be necessary for additional inspections and part replacement if damage is

found.

Table 2 - Modification

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.10 0.10

Modification (Latch 1 1.00 1.00

Fitting #1 - Figure

10)

Modification (Latch 1 1.25 1.25

Fitting #2 - Figure 14

or 15)

Modification (Latch 1 1.00 1.00

Fitting #3 - Figure

10)

Modification (Latch 1 0.75 0.75

Fitting #4 - Figure

11)

Modification (Latch 1 0.75 0.75

Fitting #5 - Figure

12)

Modification (Latch 1 1.00 1.00

Fitting #6 - Figure

13)

Modification (Latch 1 1.00 1.00

Fitting #7 - Figure

10)

Modification (Latch 1 1.00 1.00

Fitting #8 - Figure

10)

Modification (Latch 1 1.00 1.00

Fitting #9 - Figure

10)

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ALERT ALERT
Table 2 - Modification

Task Number of Persons Task Hours Elapsed Hours

Modification (Latch 1 1.00 1.00

Fitting #10 - Figure

10)

Close Access 1 0.10 0.10

Test 1 0.75 0.75

TOTAL FOR EACH AIRPLANE 10.70 10.70

NOTE: More time will be necessary for additional inspections and part replacement if damage is

found.

Table 3 - After-Modification Inspection

Task Number of Persons Task Hours Elapsed Hours

Open Access 1 0.10 0.10

Detailed Inspection 1 1.00 1.00

(Figure 1)

Close Access 1 0.10 0.10

TOTAL FOR EACH AIRPLANE 1.20 1.20

NOTE: More time will be necessary for additional inspections and part replacement if damage is

found.

H. Weight and Balance Changes

None.

I. Electrical Load Data

Not changed.

J. References

1. Existing Data

a. Boeing Service Letter 747-SL-51-048

b. Boeing Service Related Problem (SRP) 747-SRP-52-0093

c. 747-100/200/300 Aircraft Maintenance Manual (AMM) 52-32-00

d. 747-400 Aircraft Maintenance Manual (AMM) 52-32-00

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
e. Boeing Service Bulletins 747-52-2105 , "Cargo Door Latch and Lock System Revision,"

747-52-2142, "Main Deck and Lower Lobe Cargo Door Latch Pin Inspection and Fitting

Modification," 747-52-2224 , "Doors - Cargo Doors - Door Warning - Forward and Aft Lower

Lobe and Main Deck Side Cargo Door Warning System Revision" and 747-52A2258 , "Doors

- Cargo Doors - Latch Pin Direction Inspection"

f. Engineering Change Memo PRR 85901-112RS

g. Standard Overhaul Practices Manual (SOPM) 20-10-01, 20-10-02, 20-50-10

h. 747-100/200/300 Structural Repair Manual (SRM) 51, 52, 53, 53-40-01

i. 747-400 Structural Repair Manual (SRM) 51, 52, 53, 53-00-90

j. 747-400F Structural Repair Manual (SRM) 51, 52, 53, 53-00-90

k. 747-400SF Structural Repair Manual (SRM) 51, 52, 53, 53-00-90

l. Overhaul Manual (OHM) 52-36-75, 52-36-76

2. Data supplied with this Service Bulletin

a. Drawings:

Drawing No Title Sheet DCN/REV ADCN

Misc Tool Cargo Door Latch Pin Fitting Re- 1 - -

work Tool

MIT140U8005

2 - -

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

Drawing Number Title

65B17670 Sill Instl - Lower, Main Deck Cargo Door

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.

K. Publications Affected

1. Publications:

Publication Chapter-Section

747 Illustrated Parts Catalog 53-12

747-400 Illustrated Parts Catalog 53-12

2. Damage Tolerance Based Structural Inspections:

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
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. DTI requirements for the structure affected

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

L. Interchangeability and Intermixability of Parts

Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
2. MATERIAL INFORMATION

A. Material - Price and Availability

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

are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin.

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

Prices are in United States Dollars. Terms: Net 30 days.

Reference this service bulletin and submit your purchase order by one of these methods:

1. Order on-line via ATA Spec 2000 or The Boeing PART Page

2. Fax to (206) 662-7145

REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER

AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION

Unit Price as of

the Revision 1

date of this Service Bulletin (US

Dollars)

ROLT as of the

Revision 1 date of

this Service Bulletin (Calendar

Days)

Kit Number Name Date QTY

015U1899-1 Top Kit - Inspection May 12, 2010 9 382 $11,478

July 14, 2010 15

015U1899-2 Top Kit - Inspection May 13, 2010 1 382 $12,254

015U1916-1 Top Kit - Modification July 21, 2011 1 431 $5,530

August 4, 2011 14

B. Industry Support Information

Boeing warranty remedies are not available for the inspections and configuration changes given in this

service bulletin.

C. Parts Necessary For Each Airplane

1. Kits/Parts

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

NOTE: One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by

the Operator, include the parts that may be necessary for each airplane, if damage is

found.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Kit 015U1899

Existing Part Notes

Number

New Part Number QTY Name

-1 -2

Top Kit - Inspection - -

- Group 1 and

Group 2

015U1899-1 - .

Top Kit - Inspection - -

- Group 3

015U1899-2 . -

146U6107-1 . 1 SWITCH STRIKER 146U6107-1 (a) (b)

69B15457-7 9 9 PIN 69B15457-7 (a)

69B15457-8 1 1 PIN 69B15457-8 (a)

69B18044-1 1 1 BRACKET 69B18044-1 (a) (b)

69B18044-2 7 7 BRACKET 69B18044-2 (a) (b)

BACB30LM3-27 10 9 BOLT - (c)

BACB30NM3K34 . 1 BOLT, HEX HEAD - (c)

BACN10JC3CD 10 9 NUT - -

BACN10YR3CD . 1 NUT - -

BACW10BP3DP . 1 WASHER - -

NAS1149E0332P 10 10 WASHER, PLAIN - -

(a) This part is used for Production

(b) You can use the existing part to replace the new or changed part

(c) If grip length shown is not available at Boeing, fasteners supplied in kits may

be one grip length longer than indicated. Also, if any fasteners part numbers

listed are not available or have been superseded, substitute fasteners may be

supplied in kits. Boeing Document D-590 and Boeing Drawing 012W6100 are

used to determine the part numbers used as substitutes.

Kit 015U1916

Existing Part Notes

Number

New Part Number QTY Name

-1

Top Kit - Modifica- - -

tion

015U1916-1 -

(a) (b)

(c)

146U8355-1 9 PIN-LATCH 69B15457-7

(a) (b)

(c)

146U8355-2 1 PIN-LATCH 69B15457-8

(a) (b)

(c)

PIN STOP 69B18044-2

BRACKET

146U8356-1 7

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
Kit 015U1916

Existing Part Notes

Number

New Part Number QTY Name

-1

(a) (b)

(c)

PIN STOP 69B18044-1

BRACKET

146U8356-2 1

BACB30LJ5K28 10 BOLT, HEX HEAD - (d)

BACB30LJ5K34 1 BOLT, HEX HEAD - (d)

BACN10YR5CD 10 NUT - -

BACW10BP5DP 22 WASHER-PLAIN - (d)

(a) Keep the existing part if there are other uses for it.

(b) This part is used for Production

(c) You cannot use the existing part to replace the new or changed part

(d) If grip length shown is not available at Boeing, fasteners supplied in kits

may be one grip length longer than indicated. Also, if any fasteners part

numbers listed are not available or have been superseded, substitute

fasteners may be supplied in kits. Boeing Document D-590 and Boeing

Drawing 65B88700 are used to determine the part numbers used as

substitutes.

2. Parts and Materials Supplied by the Operator

Part Number / QTY Name Notes

Specification

8 Sealant (a) (b)

ounces

BMS 5-95

For Group 3 only. Refer to

FIGURE 6.

BACW10BP3DP 2 Washer

(a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for

supplier data.

(b) The number in the QTY column assumes that parts replacement is required at all ten affected latch pin fitting locations. The actual quantity necessary will depend upon inspection

results.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
3. Parts Modified and Reidentified

New Part Number Notes

(b) (c)

Existing Part QTY Name

Number

Optional to

69B15457-5 or

69B15457-7. (a)

69B15457-3 1 Latch Pin 146U8355-1

Optional to

69B15457-3 or

69B15457-7. (a)

69B15457-5

Optional to

69B15457-3 or

69B15457-5. (a)

69B15457-7

Optional to

69B15457-4 or

69B15457-6. (a)

69B15457-2 1 Latch Pin 146U8355-2

Optional to

69B15457-2 or

69B15457-6. (a)

69B15457-4

Optional to

69B15457-2 or

69B15457-4. (a)

69B15457-6

(a) Make the change in accordance with FIGURE 16 of this service bulletin.

(b) This is the part number after the change is done in accordance with this service bulletin.

(c) This part is used in production.

None.

4. Parts Removed and Not Replaced

None.

D. Parts Necessary to Change Spares

None.

E. Special Tooling - Price and Availability

Boeing can supply the tool shown in Paragraph 2.F., Special Tooling Necessary to do this Service

Bulletin. Operators are encouraged to share schedule requirements with Boeing for incorporation of

the service bulletin by e-mail to ServiceBulletinRentalLoanTools@boeing.com. The tool is subject to

the terms and conditions of the Boeing standard purchase order acknowledgement. Prices are in United

States dollars. Terms: Net 30 days.

Reference this service bulletin and submit your purchase order by one of these methods:

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
1. Order on-line via ATA Spec 2000 or Boeing Part Page

2. Fax to (425) 965-8237

Rental Data:

Daily Price as of

the Revision 1

date of this service bulletin (US

Dollars)

Tool Kit Number Name

Cargo Door Latch Pin Fitting (a)

Rework Tool

MIT140U8005-1

(a) Pricing data was not available at the time of release of this service

bulletin. Refer to the Boeing PART page on MyBoeingFleet.com or

contact First Responder at fr@boeing.com for the latest price information.

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

Cargo Door Latch Pin Fitting

Rework Tool

MIT140U8005-1

NOTE: Reamer Kit MIT140U8005-14, which is a component of Tool Kit MIT140U8005-1, can be

ordered if additional reamers are needed.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
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BOEING SERVICE BULLETIN 747-52A2294

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

– Hole dimensions for standard solid rivets and fasteners are in Structural Repair

Manual (SRM) Chapter 51

– Torque limits to tighten nuts and bolts are in SRM Chapter 51

4. Use the approved fastener and process material substitutions in accordance with

SRM Chapter 51.

5. If the length of any fastener specified in this service bulletin does not meet installation

standards given in SRM Chapter 51, then a fastener of the same specification, or

an approved substitute, with a length which meets the installation standards given

in SRM Chapter 51 may be used. In addition, washers may be installed for fastener

grip length in accordance with SRM Chapter 51.

6. Boeing Service Letter 747-SL-51-048, Damage Reporting and Repair Plan/Design

Guidelines, is an acceptable procedure to request information from Boeing for

additional structural repair instructions. The Service Letter describes what information

must be provided to Boeing before a structural repair can be provided.

7. These work instructions refer to procedures included in 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.

8. 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.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
9. The instructions in Paragraph 3.B., Work Instructions and the figures can include

operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated

Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing

Index contain data on versions of the tools or test equipment that you can use. It is

permitted to use replaced tools. It is not permitted to use superseded tools.

10. If it is necessary to remove more parts for access, you can remove those parts. If

you can get access without removing identified parts, it is not necessary to remove

all of the identified parts. Jacking and shoring limitations must be observed.

11. Where the work instructions include installation of a kept part, a new or serviceable

part with the same part number can be installed as an alternative to the kept part.

The removed part can be discarded if a new or serviceable part is installed.

12. Some Boeing parts are supplied in a temporary configuration. Those parts are

identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is

permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-'

(dash) part number. Boeing Drawing 005W0900 contains more data.

B. WORK INSTRUCTIONS

PART 1 - Latch Pin Retention Bolt and Latch Pin Inspection

1. Open the Main Deck Side Cargo Door (MDSCD) as necessary to get access to the latch pin fittings

(10 locations) on the lower sill of the door cutout. Refer to 747-100/200/300 AMM 52-32-00 or

747-400 AMM 52-32-00 as accepted procedures.

2. Do a Detailed Inspection of the MDSCD latch pin retention nuts and bolts and measure the latch

pins in accordance with FIGURE 1.

3. At any MDSCD latch pin fitting location where the retention bolt and nut was not found to be loose,

broken, damaged or missing, and the latch pin is not damaged beyond the limits given in FIGURE

1, do a torque check of the retention bolt in accordance with PART 2.

4. At any MDSCD latch pin fitting location where the retention bolt and nut was not found to be loose,

broken, damaged or missing, but the latch pin is damaged beyond the limits given in FIGURE 1,

replace the latch pin, retention bolt, and related parts in accordance with PART 4.

5. At any MDSCD latch pin fitting location where the retention bolt or nut was found to be broken,

loose, damaged or missing, check the latch pin for migration in accordance with PART 3.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
PART 2 - Torque Check

1. Do a torque check on the MDSCD latch pin retention bolt on the latch pin fitting in accordance with

FIGURE 2.

2. At any latch pin location where the retention bolt fails the torque check (the bolt or nut cannot resist

the applied torque), consider the bolt to be broken. Check the latch pin for migration in accordance

with PART 3.

3. At any latch pin location where the retention bolt passes the torque check (the bolt or nut resists

the applied torque), reapply BMS 5-95 sealant to the retention bolt head (or nut, as applicable).

4. Continue to PART 5.

PART 3 - Inspection for Latch Pin Migration

1. At any latch pin fitting location where the torque check failed or the retention bolt or nut was found

to be broken, loose, damaged or missing:

a. If any parts were found to be missing, to prevent foreign object damage do a search for the

missing parts in the vicinity of the affected latch pin fitting on the lower sill and on the ground

below.

b. Check the position of the latch pin in accordance with FIGURE 3 to determine if the latch pin

has migrated from its nominal installed position.

c. If the latch pin has migrated, do the steps that follow:

(1) Do Detailed Inspections of the latch pin fitting and the adjacent (forward and aft) latch

pin fittings, the door cutout structure within 42 inches of the affected latch pin fitting, the

affected latch cam and the adjacent (forward and aft) latch cams on the door, and the

door structure within 42 inches of the affected latch cam for damage. Remove linings and

cargo handling equipment as necessary for access.

NOTE: The Detailed Inspections are intended to find distressed fasteners, deformation

in structure, cracks, and other damage.

(2) Repair any damage that is found as listed below. As an alternative to repair, replace

damaged parts or ask Boeing for repair data and install the repair.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
(a) Repair fuselage structure in accordance with SRM Chapter 53. Repair door structure

in accordance with SRM Chapter 52

(b) Repair latch pin fittings in accordance with 747-100/200/300 SRM 53-40-01, 747-400

SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM

53-00-90 Repair 1.

(c) Components of the Main Deck Side Cargo Door mechanisms can be repaired in

accordance with OHM 52-36-75 or OHM 52-36-76

(3) Disassemble and replace the latch pin, retention bolt, and related parts in accordance

with PART 4. If not already replaced during this inspection, also disassemble and replace

the latch pin, retention bolt, and related parts at any latch pin fitting location adjacent to

(one fitting position forward and aft of) the migrated latch pin location in accordance with

PART 4.

d. If the latch pin has not migrated, disassemble and replace the latch pin, retention bolt, and

related parts in accordance with PART 4.

2. Continue to PART 5.

PART 4 - Disassembly and Replacement

1. At any latch pin fitting location where the retention bolt or nut was found to be broken or loose, or

where a retention bolt failed the torque check, or where the latch pin is damaged beyond the limits

given in FIGURE 1, disassemble, inspect and install new parts in accordance with:

a. All Groups:

FIGURE 4, for latch pin fitting positions #1, #3, #7, #8, #9 and #10.

FIGURE 7, for latch pin fitting position #4.

FIGURE 8, for latch pin fitting position #5.

FIGURE 9, for latch pin fitting position #6.

b. Group 1-2, Configuration 2:

FIGURE 5, for latch pin fitting position #2.

c. Group 1-2, Configuration 1; Group 3:

FIGURE 6, for latch pin fitting position #2.

Repair any damage that is found as listed below. As an alternative to repair, replace damaged

parts or ask Boeing for repair data and install the repair.

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
a. Repair fuselage structure in accordance with SRM Chapter 53. Repair door structure in

accordance with SRM Chapter 52

b. Repair latch pin fittings in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM

53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair

1.

c. Components of the Main Deck Side Cargo Door mechanisms can be repaired. Refer to OHM

52-36-75 and OHM 52-36-76 as accepted procedures.

2. Continue to PART 5

PART 5 - Restoration

1. If any latch pin fitting was removed from the airplane, adjust the MDSCD. Refer to the task

"Adjustment - Side Cargo Door System" in 747-100/200/300 AMM 52-32-00 or "Adjustment - Side

Cargo Door" in 747-400 AMM 52-32-00 as accepted procedures.

2. After all ten MDSCD latch pin fitting retention bolts have either passed the torque check in

accordance with PART 2 or been replaced in accordance with PART 4, and all ten MDSCD latch

pins are within the damage limit given in FIGURE 1 , close the MDSCD electrically. Refer to

747-100/200/300 AMM 52-32-00 or 747-400 AMM 52-32-00 as accepted procedures. Make sure

that the latch cams turn freely and engage and disengage the latch pins during normal operation.

3. Put the airplane back to a serviceable condition. Do the inspection again at the time given in

Paragraph 1.E., Compliance , Table 1. Modify the latch pin installations in accordance with PART

6 at the time given in Paragraph 1.E., Compliance , Table 2.

PART 6 - Modification

1. Open the Main Deck Side Cargo Door (MDSCD) as necessary to get access to the latch pin fittings

(10 locations) on the lower sill of the door cutout. Refer to 747-100/200/300 AMM 52-32-00 or

747-400 AMM 52-32-00 as accepted procedures.

NOTE: If not previously accomplished, Boeing recommends that the MDSCD modification in

Boeing Service Bulletin 747-52-2224 be installed prior to or at the same time as the

modification in this service bulletin. Service Bulletin 747-52-2224 changes the configuration

at latch pin fitting position #2.

2. Disassemble, inspect, and modify the latch pin fitting, and install new parts in accordance with:

a. All Groups:

FIGURE 10, for latch pin fitting positions #1, #3, #7, #8, #9 and #10.

FIGURE 11, for latch pin fitting position #4.

FIGURE 12, for latch pin fitting position #5.

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ALERT ALERT
FIGURE 13, for latch pin fitting position #6.

b. Group 1-2, Configuration 2:

FIGURE 14, for latch pin fitting position #2.

c. Group 1-2, Configuration 1; Group 3:

FIGURE 15, for latch pin fitting position #2.

NOTE: Existing 69B15457-3, -4, -5, -6, -7, and -8 latch pins can be reworked in accordance with

FIGURE 16. Existing 69B15457-1 and -2 latch pins must first be reworked into 69B15457-3

and -4 latch pins in accordance with Boeing Service Bulletin 747-52-2105, "Cargo Door

Latch and Lock System Revision".

3. If any latch pin fitting was removed from the airplane, adjust the MDSCD. Refer to the task

"Adjustment - Side Cargo Door System" in 747-100/200/300 AMM 52-32-00 or "Adjustment - Side

Cargo Door" in 747-400 AMM 52-32-00 as accepted procedures.

4. Close the MDSCD electrically. Refer to 747-100/200/300 AMM 52-32-00 or 747-400 AMM 52-32-00

as accepted procedures. Make sure that the latch cams turn freely and engage and disengage

the latch pins during normal operation.

5. Put the airplane back to a serviceable condition. After modification of all 10 latch pin fittings, start

to do inspections in accordance with PART 7 at the times given in Paragraph 1.E., Compliance,

Table 3.

PART 7 - After-Modification Inspection

1. Open the Main Deck Side Cargo Door (MDSCD) as necessary to get access to the latch pin fittings

(10 locations) on the lower sill of the door cutout. Refer to 747-100/200/300 AMM 52-32-00 or

747-400 AMM 52-32-00 as accepted procedures.

2. Do a Detailed Inspection of the MDSCD latch pin retention nuts and bolts, inspect for damage or

corrosion, and measure the latch pins in accordance with FIGURE 1.

3. At any MDSCD latch pin fitting location where the retention bolt and nut was not found to be loose,

broken or missing, but the latch pin is damaged beyond the limits given in FIGURE 1, replace the

latch pin, retention bolt, and related parts in accordance with PART 6.

NOTE: PART 6 includes instructions to modify the latch pin fittings by making the retention bolt

holes in the latch pin fittings larger. This latch pin fitting modification is only necessary

the first time PART 6 is accomplished.

4. At any MDSCD latch pin fitting location where the retention bolt or nut was found to be broken,

loose, damaged or missing, check the latch pin for migration in accordance with the steps that

follow:

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ALERT ALERT
a. If any parts were found to be missing, to prevent foreign object damage do a search for the

missing parts in the vicinity of the affected latch pin fitting on the lower sill and on the ground

below.

b. Check the position of the latch pin in accordance with FIGURE 3 to determine if the latch pin

has migrated from its nominal installed position.

c. If the latch pin has migrated, do the steps that follow:

(1) Do Detailed Inspections of the latch pin fitting and the adjacent (forward and aft) latch

pin fittings, the door cutout structure within 42 inches of the affected latch pin fitting, the

affected latch cam and the adjacent (forward and aft) latch cams on the door, and the

door structure within 42 inches of the affected latch cam for damage. Remove linings and

cargo handling equipment as necessary for access.

NOTE: The Detailed Inspections are intended to find distressed fasteners, deformation

in structure, cracks, and other damage.

(2) Repair any damage that is found as listed below. As an alternative to repair, replace

damaged parts or ask Boeing for repair data and install the repair.

(a) Repair fuselage structure in accordance with SRM Chapter 53. Repair door structure

in accordance with SRM Chapter 52

(b) Repair latch pin fittings in accordance with 747-100/200/300 SRM 53-40-01, 747-400

SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM

53-00-90 Repair 1.

(c) Components of the Main Deck Side Cargo Door mechanisms can be repaired. Refer

to OHM 52-36-75 and OHM 52-36-76 as accepted procedures.

(3) Disassemble and replace the latch pin, retention bolt, and related parts in accordance

with PART 6. If not already replaced, also disassemble and replace the latch pin, retention

bolt, and related parts at any latch pin fitting location adjacent to (one fitting position

forward and aft of) the migrated latch pin location in accordance with PART 6.

NOTE: PART 6 includes instructions to modify the latch pin fittings by making the

retention bolt holes in the latch pin fittings larger. This latch pin fitting modification

is only necessary the first time PART 6 is accomplished.

d. If the latch pin has not migrated, disassemble and replace the latch pin, retention bolt, and

related parts in accordance with PART 6.

NOTE: PART 6 includes instructions to modify the latch pin fittings by making the retention

bolt holes in the latch pin fittings larger. This latch pin fitting modification is only

necessary the first time PART 6 is accomplished.

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ALERT ALERT
5. If any latch pin fitting was removed from the airplane, adjust the MDSCD. Refer to the task

"Adjustment - Side Cargo Door System" in 747-100/200/300 AMM 52-32-00 or "Adjustment - Side

Cargo Door" in 747-400 AMM 52-32-00 as accepted procedures.

6. Close the MDSCD electrically. Refer to 747-100/200/300 AMM 52-32-00 or 747-400 AMM 52-32-00

as accepted procedures. Make sure that the latch cams turn freely and engage and disengage

the latch pins during normal operation.

7. Put the airplane back to a serviceable condition. Continue to do inspections in accordance with

PART 7 at the times given in Paragraph 1.E., Compliance, Table 3.

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ALERT ALERT
FIGURE 1: DETAILED INSPECTION

(SHEET 1 OF 2)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
The step number shown below agrees with the numbers shown in the circle symbols in the figure. The QTY

numbers shown below are the number of parts necessary for one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

Measure the diameter of the exposed

portion of the latch

pin. Diameter should

not be less than

1.324 inches.

1 Measure Latch Pin - 1

Do a detailed inspection of the latch pin

for damage. It is not

necessary to remove

the latch pin for this

inspection.

Inspect Latch Pin - 1

Do a Detailed Inspection to make sure

that the bolt is not

loose, broken or

missing.

2 Inspect Bolt - 1

Do a Detailed Inspection to make sure

that the nut is not

loose, broken or

missing.

Inspect Nut - 1

FIGURE 1: DETAILED INSPECTION

(SHEET 2 OF 2)

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ALERT ALERT
FIGURE 2: TORQUE CHECK

(SHEET 1 OF 2)

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49 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

From bolt head. Optional: Remove

sealant from the nut.

1 Remove Sealant BMS 5-95 -

Apply 13 - 15 inchpounds of torque to

the bolt head. Optional: Apply 13 - 15

inch-pounds of

torque to the nut.

2 Torque Bolt - -

FIGURE 2: TORQUE CHECK

(SHEET 2 OF 2)

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ALERT ALERT
FIGURE 3: LATCH PIN POSITION CHECK

(SHEET 1 OF 3)

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ALERT ALERT
FIGURE 3: LATCH PIN POSITION CHECK

(SHEET 2 OF 3)

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BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 (a)

Remove Washer - 1 (a)

Remove Bolt - 1 (a)

Remove Bracket - - If installed.

Check if the latch pin

has migrated away

from the nominal installed position. (b)

2 Inspect Latch Pin - 1

(a) Unless the parts are found to be missing. If the retention bolt is fractured, use care to remove the sections

of the bolt from the latch pin fitting. If both ends of the bolt have been sheared, the shank of the bolt may

be trapped in the latch pin.

(b) If the retention bolt hole in the latch pin is not aligned with the retention bolt hole in the latch pin fitting,

consider the pin to have migrated. If the operator wishes to measure and record the distance (forward or

aft) that the latch pin has migrated, this is one method that can be used: 1. Look into the retention bolt

hole in the latch pin fitting. If the hole in the latch pin is not aligned with the hole in the fitting, make a mark

on the protruding end of the latch pin at the edge of the latch pin fitting lug. 2. Move the latch pin as necessary to align the hole in the latch pin with the hole in the fitting, and make another mark on the protruding

end of the latch pin at the edge of the latch pin fitting lug. 3. Remove the latch pin and measure the distance

between the two marks. The distance measured is the distance the pin has migrated.

FIGURE 3: LATCH PIN POSITION CHECK

(SHEET 3 OF 3)

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ALERT ALERT
FIGURE 4: PART REPLACEMENT AT LATCH PIN FITTING POSITIONS #1, #3, #7, #8, #9 AND #10

(SHEET 1 OF 3)

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54 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 1

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

If installed, and if not

previously removed

to check for latch pin

migration.

Remove BRACKET 69B18044-2 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN 69B15457-7 1

Between the latch

pin fitting and the

flanges of the bracket.

5 Apply Sealant BMS 5-95 -

Install (New) BRACKET 69B18044-2 1 (e)

FIGURE 4: PART REPLACEMENT AT LATCH PIN FITTING POSITIONS #1, #3, #7, #8, #9 AND #10

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Wet with BMS 5-95

sealant.

6 Install (New) BOLT BACB30LM3-27 1

Install 1 or 2 washers, as necessary.Install (New) WASHER, PLAIN NAS1149E0332P 2

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

7 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) It is acceptable to reinstall the bracket that was previously removed, if it is in serviceable condition.

FIGURE 4: PART REPLACEMENT AT LATCH PIN FITTING POSITIONS #1, #3, #7, #8, #9 AND #10

(SHEET 3 OF 3)

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ALERT ALERT
This Figure applies only to: Group 1-2, Configuration 2.

FIGURE 5: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 1 OF 3)

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57 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 1

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

If installed, and if not

previously removed

to check for latch pin

migration.

Remove BRACKET 69B18044-2 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) Latch Pin 69B15457-7 1

between the latch

pin fitting and the

flanges of the bracket.

5 Apply Sealant BMS 5-95 -

Install (New) BRACKET 69B18044-2 1 (e)

FIGURE 5: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 2 OF 3)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

6 Install (New) BOLT BACB30LM3-27 1

Install 1 or 2 washers, as necessary.Install (New) WASHER, PLAIN NAS1149E0332P 2

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

7 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) It is acceptable to reinstall the bracket that was previously removed, if it is in serviceable condition.

FIGURE 5: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 3 OF 3)

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ALERT ALERT
This Figure applies only to: Group 1-2, Configuration 1; Group 3.

FIGURE 6: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 1 OF 3)

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60 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 3

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

If installed, and if not

previously removed

to check for latch pin

migration.

Remove BRACKET 69B18044-2 1

If installed, and if not

previously removed

to check for latch pin

migration.

Remove Switch Striker 146U6107-1 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) Latch Pin 69B15457-7 1

Between the latch

pin fitting and the

flanges of the bracket.

5 Apply Sealant BMS 5-95 -

Install (New) BRACKET 69B18044-2 1 (e)

FIGURE 6: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Between the switch

striker and the

flanges of the bracket.

6 Apply Sealant BMS 5-95 -

Install (New) SWITCH STRIKER 146U6107-1 1 (e)

wet with BMS 5-95

sealant.

7 Install (New) BOLT, HEX HEAD BACB30NM3K34 1

Between the switch

striker and the

bracket.

Install (New) WASHER BACW10BP3DP 2

Install (New) WASHER BACW10BP3DP 1 Under the nut.

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

8 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) It is acceptable to reinstall the bracket and switch striker that was previously removed, if they are in serviceable condition.

FIGURE 6: PART REPLACEMENT AT LATCH PIN FITTING POSITION #2

(SHEET 3 OF 3)

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ALERT ALERT
FIGURE 7: PART REPLACEMENT AT LATCH PIN FITTING POSITION #4

(SHEET 1 OF 3)

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63 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 1

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN 69B15457-8 1

wet with BMS 5-95

sealant.

5 Install (New) BOLT BACB30LM3-27 1

Install 1 or 2 washers, as necessary.Install (New) WASHER, PLAIN NAS1149E0332P 2

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

6 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

FIGURE 7: PART REPLACEMENT AT LATCH PIN FITTING POSITION #4

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting on both the forward and aft ends of the fitting. Use care to keep the tapered end of the pin, which

will be engaged by the door latch cams, free of sealant.

FIGURE 7: PART REPLACEMENT AT LATCH PIN FITTING POSITION #4

(SHEET 3 OF 3)

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ALERT ALERT
FIGURE 8: PART REPLACEMENT AT LATCH PIN FITTING POSITION #5

(SHEET 1 OF 3)

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66 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 1

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN 69B15457-7 1

wet with BMS 5-95

sealant.

5 Install (New) BOLT BACB30LM3-27 1

Install 1 or 2 washers, as necessary.Install (New) WASHER, PLAIN NAS1149E0332P 2

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

6 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

FIGURE 8: PART REPLACEMENT AT LATCH PIN FITTING POSITION #5

(SHEET 2 OF 3)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting on both the forward and aft ends of the fitting. Use care to keep the tapered end of the pin, which

will be engaged by the door latch cams, free of sealant.

FIGURE 8: PART REPLACEMENT AT LATCH PIN FITTING POSITION #5

(SHEET 3 OF 3)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
FIGURE 9: PART REPLACEMENT AT LATCH PIN FITTING POSITION #6

(SHEET 1 OF 3)

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69 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If not previously removed to check for

latch pin migration.

1 Remove Nut - 1

If not previously removed to check for

latch pin migration.

Remove Washer - 1

If not previously removed to check for

latch pin migration.

Remove Bolt - 1

If installed, and if not

previously removed

to check for latch pin

migration.

Remove BRACKET 69B18044-1 1

2 Remove Latch Pin - 1 -

3 Inspect Latch Pin Fitting - - (a) (b)

Inspect Door Latch Cams - - Not shown (a)

Remove old sealant

from the bore.

Clean Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

4 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) Latch Pin 69B15457-7 1

between the latch

pin fitting and the

flanges of the bracket.

5 Apply Sealant BMS 5-95 -

Install (New) BRACKET 69B18044-1 1 (e)

FIGURE 9: PART REPLACEMENT AT LATCH PIN FITTING POSITION #6

(SHEET 2 OF 3)

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70 of 97

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

6 Install (New) BOLT BACB30LM3-27 1

Install 1 or 2 washers, as necessary.Install (New) WASHER, PLAIN NAS1149E0332P 2

Apply 33 - 37 inchpounds of torque to

the nut (optional: apply torque to the bolt

head.)

Install (New) NUT BACN10JC3CD 1

7 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) It is acceptable to reinstall the bracket that was previously removed, if it is in serviceable condition.

FIGURE 9: PART REPLACEMENT AT LATCH PIN FITTING POSITION #6

(SHEET 3 OF 3)

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ALERT ALERT
FIGURE 10: MODIFICATION AT LATCH PIN FITTING POSITION #1, #3, #7, #8, #9 AND #10

(SHEET 1 OF 4)

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72 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

3. On commonly affected airplanes, installation of a pin stop bracket in accordance with this

figure supersedes the pin stop bracket installation shown in Boeing Service Bulletin

747-52-2142 for the affected latch pin fitting position.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -

Remove Washer - 1 -

Remove Bolt - 1 -

Remove Bracket - 1 If installed.

2 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

3 Clean Latch Pin Fitting - -

4 Inspect Latch Pin Fitting - - (a) (b) (e)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 10: MODIFICATION AT LATCH PIN FITTING POSITION #1, #3, #7, #8, #9 AND #10

(SHEET 2 OF 4)

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ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (f)

5 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

6 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-1 1

Between the latch

pin fitting and the

flanges of the bracket.

7 Apply Sealant BMS 5-95 -

Install (New) PIN STOP BRACKET 146U8356-1 1 -

FIGURE 10: MODIFICATION AT LATCH PIN FITTING POSITION #1, #3, #7, #8, #9 AND #10

(SHEET 3 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Wet with BMS 5-95

sealant.

8 Install (New) BOLT, HEX HEAD BACB30LJ5K28 1

Install 1 or 2 washers, as necessary.Install (New) WASHER-PLAIN BACW10BP5DP 2

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

9 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(f) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 10: MODIFICATION AT LATCH PIN FITTING POSITION #1, #3, #7, #8, #9 AND #10

(SHEET 4 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
FIGURE 11: MODIFICATION AT LATCH PIN FITTING POSITION #4

(SHEET 1 OF 4)

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Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

76 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -

Remove Washer - 1 -

Remove Bolt - 1 -

2 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

3 Clean Latch Pin Fitting - -

4 Inspect Latch Pin Fitting - - (a) (b) (e)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 11: MODIFICATION AT LATCH PIN FITTING POSITION #4

(SHEET 2 OF 4)

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Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

77 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (f)

5 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

6 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-2 1

FIGURE 11: MODIFICATION AT LATCH PIN FITTING POSITION #4

(SHEET 3 OF 4)

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78 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

7 Install (New) BOLT, HEX HEAD BACB30LJ5K28 1

Install 1 or 2 washers, as necessary.Install (New) WASHER-PLAIN BACW10BP5DP 2

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

8 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting on both the forward and aft ends of the fitting. Use care to keep the tapered end of the pin, which

will be engaged by the door latch cams, free of sealant.

(e) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(f) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 11: MODIFICATION AT LATCH PIN FITTING POSITION #4

(SHEET 4 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
FIGURE 12: MODIFICATION AT LATCH PIN FITTING POSITION #5

(SHEET 1 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

80 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -.

Remove Washer - 1 -

Remove Bolt - 1 -

2 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

3 Clean Latch Pin Fitting - -

4 Inspect Latch Pin Fitting - - (a) (b) (e)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 12: MODIFICATION AT LATCH PIN FITTING POSITION #5

(SHEET 2 OF 4)

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Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

81 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (f)

5 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

6 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-1 1

FIGURE 12: MODIFICATION AT LATCH PIN FITTING POSITION #5

(SHEET 3 OF 4)

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Revision 1 August 16, 2011 747-52A2294

82 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

7 Install (New) BOLT, HEX HEAD BACB30LJ5K28 1

Install 1 or 2 washers, as necessary.Install (New) WASHER-PLAIN BACW10BP5DP 2

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

8 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting on both the forward and aft ends of the fitting. Use care to keep the tapered end of the pin, which

will be engaged by the door latch cams, free of sealant.

(e) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(f) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 12: MODIFICATION AT LATCH PIN FITTING POSITION #5

(SHEET 4 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
FIGURE 13: MODIFICATION AT LATCH PIN FITTING POSITION #6

(SHEET 1 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

84 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

3. On commonly affected airplanes, installation of a pin stop bracket in accordance with this

figure supersedes the pin stop bracket installation shown in Boeing Service Bulletin

747-52-2142 for the affected latch pin fitting position.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -

Remove Washer - 1 -

Remove Bolt - 1 -

Remove Bracket - 1 If installed.

2 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

3 Clean Latch Pin Fitting - -

4 Inspect Latch Pin Fitting - - (a) (b) (e)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 13: MODIFICATION AT LATCH PIN FITTING POSITION #6

(SHEET 2 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

85 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (f)

5 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

6 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-1 1

between the latch

pin fitting and the

flanges of the pin

stop bracket.

7 Apply Sealant BMS 5-95 -

Install (New) PIN STOP BRACKET 146U8356-2 1 -

FIGURE 13: MODIFICATION AT LATCH PIN FITTING POSITION #6

(SHEET 3 OF 4)

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Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

86 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

8 Install (New) BOLT, HEX HEAD BACB30LJ5K28 1

Install 1 or 2 washers, as necessary.Install (New) WASHER-PLAIN BACW10BP5DP 2

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

9 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(f) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 13: MODIFICATION AT LATCH PIN FITTING POSITION #6

(SHEET 4 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

87 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
This Figure applies only to: Group 1-2, Configuration 2.

FIGURE 14: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 1 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

88 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

3. On commonly affected airplanes, installation of a pin stop bracket in accordance with this

figure supersedes the pin stop bracket installation shown in Boeing Service Bulletin

747-52-2142 for the affected latch pin fitting position.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -

Remove Washer - 1 -

Remove Bolt - 1 -

Remove Bracket - 1 If installed.

2 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

3 Clean Latch Pin Fitting - -

4 Inspect Latch Pin Fitting - - (a) (b) (e)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 14: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 2 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

89 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (f)

5 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

6 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-1 1

between the latch

pin fitting and the

flanges of the bracket.

7 Apply Sealant BMS 5-95 -

Install (New) PIN STOP BRACKET 146U8356-1 1 -

FIGURE 14: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 3 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

90 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
STEP TASK NAME IDENTIFICATION QTY MORE DATA

wet with BMS 5-95

sealant.

8 Install (New) BOLT, HEX HEAD BACB30LJ5K28 1

Install 1 or 2 washers, as necessary.Install (New) WASHER-PLAIN BACW10BP5DP 2

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

9 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(f) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 14: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 4 OF 4)

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91 of 97

BOEING SERVICE BULLETIN 747-52A2294

ALERT ALERT
This Figure applies only to: Group 1-2, Configuration 1; Group 3.

FIGURE 15: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 1 OF 4)

BOEING PROPRIETARY -

Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 08, 2010

Revision 1 August 16, 2011 747-52A2294

92 of 97

BOEING SERVICE BULLETIN 747-52A2294

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 one latch pin fitting location.

NOTE: The procedure given below assumes that each affected latch pin fitting will be reworked while

installed on the airplane. As an alternative, the latch pin fittings can be removed from the

airplane and reworked. The retention bolt hole in latch pin fittings that are removed from the

airplane can be made larger using standard machine tools rather than with the special tool

described below. Refer to SOPM 20-10-01 and SOPM 20-10-02 for requirements when

machining high strength steel.

1.

2. If any latch pin fitting is removed from the airplane, it will be necessary to adjust the MDSCD

as described in Paragraph 3.B., Work Instructions, PART 6.

3. On commonly affected airplanes, installation of a pin stop bracket in accordance with this

figure supersedes the pin stop bracket installation shown in Boeing Service Bulletin

747-52-2142 for the affected latch pin fitting position.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Remove Nut - 1 -.

Remove Washer - 3 -

Remove Bolt - 1 -

Remove Bracket - 1 If installed.

Remove / Keep Switch Striker 146U6107-1 1 -

2 Drill / Ream Switch Striker 146U6107-1 2 (e)

3 Remove Latch Pin - 1 -

Remove old sealant

from the bore.

4 Clean Latch Pin Fitting - -

5 Inspect Latch Pin Fitting - - (a) (b) (f)

Inspect Door Latch Cams - - Not shown (a)

FIGURE 15: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 2 OF 4)

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STEP TASK NAME IDENTIFICATION QTY MORE DATA

Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to Boeing Tool Kit

MIT140U8005-1 for

an accepted procedure. (g)

6 Drill / Ream Retention Bolt Hole - 1

Clean/Deburr Latch Pin Fitting - - Break sharp edges.

Apply one coat of

primer to any bare

metal surface on the

outside of the fitting.

After the first coat is

dry, apply a second

coat of primer.

Apply Primer BMS 10-11, TYPE I -

Mark "modified by

SB 747-52A2294"

on the fitting to identify that this service

bulletin has been

done. Refer to

SOPM 20-50-10

(method: rubber

stamp with a protective overcoat) as an

accepted procedure.

Identify Latch Pin Fitting - -

To the outer diameter of the pin and to

the bore of the fitting.

7 Apply Sealant BMS 5-95 -

Install the pin while

the sealant is still

wet. Line up the retention bolt holes in

the latch pin with the

holes in the latch pin

fitting.

Install (New) PIN-LATCH 146U8355-1 1

Between the latch

pin fitting and the

flanges of the bracket.

8 Apply Sealant BMS 5-95 -

Install (New) PIN STOP BRACKET 146U8356-1 1 -

FIGURE 15: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 3 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

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STEP TASK NAME IDENTIFICATION QTY MORE DATA

Between the switch

striker and the

flanges of the bracket.

9 Apply Sealant BMS 5-95 -

Install (Kept) Switch Striker 146U6107-1 1 -

wet with BMS 5-95

sealant.

10 Install (New) BOLT, HEX HEAD BACB30LJ5K34 1

Between the switch

striker and the

bracket.

Install (New) WASHER-PLAIN BACW10BP5DP 2

Install (New) WASHER-PLAIN BACW10BP5DP 1 Under the nut.

Apply 120 - 130

inch-pounds of

torque to the nut

(optional: apply

torque to the bolt

head.)

Install (New) NUT BACN10YR5CD 1

11 Apply Sealant BMS 5-95 - (c) (d)

(a) Do a Detailed Inspection of the affected fitting and the corresponding door latch cams for evidence of

impact damage. If damage is found, contact Boeing for repair instructions and do the repair. Restore

damaged finishes as necessary.

(b) Do a Detailed Inspection of the retention bolt holes in the fitting for cracks or other damage. If damage is

found, contact Boeing for repair instructions and do the repair.

(c) Encapsulate bolt head, nut, washer, and bolt threads. Fillet seal the periphery of the bolt inside the pin.

(d) Apply a fillet seal of BMS 5-95 sealant all around the latch pin at the space between the latch pin and the

fitting. Use care to keep the tapered end of the pin, which will be engaged by the door latch cams, free

of sealant. It is not necessary to fillet seal the end of the fitting covered by the bracket.

(e) Make the retention bolt holes in the switch striker larger, to 0.342 - 0.354 inch diameter. After rework,

apply one coat of BMS 10-11 Type I primer to any bare metal areas of the part. After the first primer coat

dries, apply a second coat of BMS 10-11 Type I primer and one coat of BMS-10-11, Type II enamel.

(f) Do a Detailed Inspection of the pin bore and the retention bolt hole of the latch pin fitting for corrosion. If

corrosion is found, repair in accordance with 747-100/200/300 SRM 53-40-01, 747-400 SRM 53-00-90

Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-00-90 Repair 1.

(g) This procedure can be used on fittings that have been repaired in accordance with 747-100/200/300 SRM

53-40-01, 747-400 SRM 53-00-90 Repair 1, 747-400F SRM 53-00-90 Repair 1, or 747-400SF SRM 53-

00-90 Repair 1.

FIGURE 15: MODIFICATION AT LATCH PIN FITTING POSITION #2

(SHEET 4 OF 4)

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BOEING SERVICE BULLETIN 747-52A2294

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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 one latch pin.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

(a) Increase hole diameter to 0.3140 -

0.3180 inch. Refer

to SOPM 20-10-01

and SOPM 20-10-02

for requirements

when machining

high strength steel.

1 Drill / Ream Latch Pin - 1

Break sharp edges.

Maintain a 63 microinch finish on the

outer surface of the

latch pin. Maintain a

125 inch microinch

finish on all other

surfaces.

2 Clean/Deburr Latch Pin - 1

Apply one coat of

primer to any bare

metal surface on the

outside of the pin.

After the first coat is

dry, apply a second

coat of primer.

3 Apply Primer BMS 10-11, TYPE I -

FIGURE 16: LATCH PIN REWORK

(SHEET 1 OF 2)

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STEP TASK NAME IDENTIFICATION QTY MORE DATA

(b) (c) Rubber stamp

new part number on

pin. Refer to SOPM

20-50-10 as an accepted procedure.

4 Identify Latch Pin - -

(a) Applicable to 69B15457-3, -4, -5, -6, -7 or -8 latch pins. Existing 69B15457-1 and -2 latch pins must first

be reworked into 69B15457-3 and -4 latch pins in accordance with Boeing Service Bulletin 747-52-2105,

"Cargo Door Latch and Lock System Revision".

(b) Identify modified 69B15457-3, -5 or -7 latch pins as 146U8355-1.

(c) Identify modified 69B15457-4, -6 or -8 latch pins as 146U8355-2.

FIGURE 16: LATCH PIN REWORK

(SHEET 2 OF 2)

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ALERT ALERT