# Boeing Alert Requirements Bulletin 737-53A1380 RB: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2018-0959; AD 2019-03-24 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Requirements Bulletin 737-53A1380 RB](https://openairdocs.org/service-documents/boeing/737-53a1380-rb.md)
- Title as filed: SB 737-53A1380 RB
- Pages: 46
- PDF: https://openairdocs.org/files/sha256/7e/87/7e87b66ebfc370b0618be1323f1d8e99059c98fcf3cab5f3de94d04615e631b1
- Page: https://openairdocs.org/service-documents/boeing/737-53a1380-rb/file/7e87b66ebfc3

## Text

Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1380 RB
Original Issue: July 18, 2018
ATA System: 5312
SUBJECT: FUSELAGE - Stringers and Other Longitudinal Members - Overwing Emergency Exit
Doors Lower Sill Splice Plate Inspection
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
Copyright © 2018 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
Original Issue: July 18, 2018
737-53A1380 RB
1 of 46
4.0

### Page 2

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
2 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT
BLANK PAGE

### Page 3

Table of Contents
1. EFFECTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
A. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
B. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. CONCURRENT REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. COMPLIANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. APPROVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
A. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
B. Work Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
FIGURE 1: LEFT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
FIGURE 2: RIGHT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
FIGURE 3: LEFT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT . . . . . . . . . . . . . . . . 27
FIGURE 4: RIGHT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT . . . . . . . . . . . . . . . 30
FIGURE 5: LEFT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
FIGURE 6: LEFT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTION
OF THE SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
FIGURE 7: RIGHT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
FIGURE 8: RIGHT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
FIGURE 9: LEFT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION . . . . . . . . . . . . . 41
FIGURE 10: RIGHT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION . . . . . . . . . . . . 44
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
3 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 4

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
4 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT
BLANK PAGE

### Page 5

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1380 RB
Original Issue: July 18, 2018
ATA System: 5312
SUBJECT: FUSELAGE - Stringers and Other Longitudinal Members - Overwing Emergency Exit
Doors Lower Sill Splice Plate Inspection
THIS DOCUMENT 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 DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE
NEW OWNER. THIS IS AN ENHANCED REQUIRED FOR COMPLIANCE DOCUMENT. THE BOEING
PROCESSES USED TO CREATE THE SERVICE BULLETIN (SB) AND THE REQUIREMENTS BULLETIN
(RB) ENSURE THAT THE INFORMATION BETWEEN "RC START" AND "RC END" IN THE SB ARE IDENTICAL
TO THE INFORMATION IN THE SAME SECTIONS (COMPLIANCE, WORK INSTRUCTIONS…) OF THE RB
WHICH THE SB REFERS TO AS THE RELATED DOCUMENT.
1. EFFECTIVITY
A. Airplanes
This bulletin is applicable to all 737-400 Airplanes, within line numbers 1487 through 3132, in 1 Group.
B. Spares Affected
None.
2. CONCURRENT REQUIREMENTS
None.
3. COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
Requirements Bulletin 737-53A1380 RB. The Airworthiness Directive will make the compliance tasks and
times given in Requirements Bulletin 737-53A1380 RB mandatory.
Accomplish the required actions, based on the applicable conditions in Table 1, in accordance with
Accomplishment Instructions.
When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When
more than one ACTION is given for a CONDITION or an OPTION do all of the ACTION numbers for that
CONDITION or OPTION.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
5 of 46

### Page 6

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 4,500
flight cycles af-
ter the original
issue date of
Requirements
Bulletin 737-
53A1380 RB.
Before 11,000
total flight cy-
cles.
ACTION 1: Do the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
All airplanes.
ACTION 2: Do the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
-Before further flight.CONDITION 1 (ACTION
1): Do the splice plate re-
placement on the left
side.
CONDITION 1: ANY
CRACK FOUND IN THE
LEFT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a) 9,000 flight cycles.-CONDITION 1 (ACTION2): Repeat the surface
HFEC inspections of the
lower sill splice plate at
S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
-Before further flight.Do the open hole HFEC
inspections at STA 601,
surface HFEC inspection
of the skin and a detailed
inspection of the structure
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack.
CONDITION 2: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 601
INSPECTION AREA ON
THE LEFT SIDE (a)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
6 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 7

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.CONDITION 2.1 (AC-
TION 1): Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 2.1: ANY
CRACK FOUND
-Before further flight.CONDITION 2.1 (AC-
TION 2): Do the splice
plate replacement on the
left side.
9,000 flight cycles.-CONDITION 2.1 (AC-
TION 3): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
-Before further flight.CONDITION 2.2 (AC-
TION 1): Do the splice
plate replacement on the
left side.
CONDITION 2.2: NO
CRACK FOUND
9,000 flight cycles.-CONDITION 2.2 (AC-
TION 2): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
-Before further flight.Do the open hole HFEC
inspections at STA 616,
surface HFEC inspection
of the skin and a detailed
inspection of the structure
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack.
CONDITION 3: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 616
INSPECTION AREA ON
THE LEFT SIDE (a)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
7 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 8

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.CONDITION 3.1 (AC-
TION 1): Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 3.1: ANY
CRACK FOUND
-Before further flight.CONDITION 3.1 (AC-
TION 2): Do the splice
plate replacement on the
left side.
9,000 flight cycles.-CONDITION 3.1 (AC-
TION 3): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
-Before further flight.CONDITION 3.2 (AC-
TION 1): Do the splice
plate replacement on the
left side.
CONDITION 3.2: NO
CRACK FOUND
9,000 flight cycles.-CONDITION 3.2 (AC-
TION 2): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the left side, for
any crack and any sev-
ered splice plate.
9,000 flight cycles.-Repeat the surface HFEC
inspections of the lower
sill splice plate at S-15, in
the inspection area at
STA 601 and STA 616,
on the left side, for any
crack and any severed
splice plate.
CONDITION 4: NO
CRACK FOUND IN THE
LEFT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
8 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 9

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.CONDITION 5 (ACTION
1): Do the splice plate re-
placement on the right
side.
CONDITION 5: ANY
CRACK FOUND IN THE
RIGHT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a) 9,000 flight cycles.-CONDITION 5 (ACTION2): Repeat the surface
HFEC inspections of the
lower sill splice plate at
S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
-Before further flight.Do the open hole HFEC
inspections at STA 601,
surface HFEC inspection
of the skin and a detailed
inspection of the structure
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack.
CONDITION 6: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 601
INSPECTION AREA ON
THE RIGHT SIDE (a)
-Before further flight.CONDITION 6.1 (AC-
TION 1): Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 6.1: ANY
CRACK FOUND
-Before further flight.CONDITION 6.1 (AC-
TION 2): Do the splice
plate replacement on the
right side.
9,000 flight cycles.-CONDITION 6.1 (AC-
TION 3): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
9 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 10

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.CONDITION 6.2 (AC-
TION 1): Do the splice
plate replacement on the
right side.
CONDITION 6.2: NO
CRACK FOUND
9,000 flight cycles.-CONDITION 6.2 (AC-
TION 2): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
-Before further flight.Do the open hole HFEC
inspection at STA 616,
surface HFEC inspection
of the skin and a detailed
inspection of the structure
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack.
CONDITION 7: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 616
INSPECTION AREA ON
THE RIGHT SIDE (a)
-Before further flight.CONDITION 7.1 (AC-
TION 1): Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 7.1: ANY
CRACK FOUND
-Before further flight.CONDITION 7.1 (AC-
TION 2): Do the splice
plate replacement on the
right side.
9,000 flight cycles.-CONDITION 7.1 (AC-
TION 3): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
10 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 11

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.CONDITION 7.2 (AC-
TION 1): Do the splice
plate replacement on the
right side.
CONDITION 7.2: NO
CRACK FOUND
9,000 flight cycles.-CONDITION 7.2 (AC-
TION 2): Repeat the sur-
face HFEC inspections of
the lower sill splice plate
at S-15, in the inspection
area at STA 601 and STA
616, on the right side, for
any crack and any sev-
ered splice plate.
9,000 flight cycles.-Repeat the surface HFEC
inspections of the lower
sill splice plate at S-15, in
the inspection area at
STA 601 and STA 616,
on the right side, for any
crack and any severed
splice plate.
CONDITION 8: NO
CRACK FOUND IN THE
RIGHT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
(a) More than one CONDITION can be applicable.
4. APPROVAL
This Requirements Bulletin was examined by the Federal Aviation Administration (FAA). The changes
specified in this document 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 document and its approval were based on the airplane
in its original Boeing delivery configuration or as modified by other Boeing changes.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected by
this Requirements Bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this Requirements Bulletin.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
11 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 12

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
12 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT
BLANK PAGE

### Page 13

5.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
NOTE: 1. 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 Values:
— Values for structural fasteners are given in 737 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 737
Aircraft Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 737
Aircraft Maintenance Manual (AMM).
— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
2. Use the approved fastener and process substitutions in accordance with SRM Chapter
51.
3. 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. Refer to SOPM 20-50-01 for alternate
full threaded fasteners (screws) needed for installation in this service bulletin.
4. 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.
5. 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.
6. Boeing Service Letter 737-SL-51-042, 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.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
13 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 14

7. The 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.
8. 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.
9. When more than one OPTION is given for a CONDITION, do only one of the OPTION
numbers. When more than one ACTION is given for a CONDITION or an OPTION
do all of the ACTION numbers for that CONDITION or OPTION.
10. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance.
11. This is an Enhanced Required for Compliance document. There will be a separate
Service Bulletin (SB) and a separate Requirements Bulletin (RB). If an RB is mandated
by an Airworthiness Directive (AD), then all applicable requirements specified in the
RB must be done. For the related SB, some locations are marked RC Start and RC
End to identify the requirements that are restated from the RB. For the related SB,
the areas between RC Start and RC End, including sub-steps and any figures
identified between RC Start and RC End, must be done to comply with the AD.
Therefore, an Alternative Method of Compliance (AMOC) is required for any deviations
to steps between RC Start and RC End, including substeps and identified figures.
For the related SB, the steps not between RC Start and RC End may be deviated
from using accepted methods in accordance with the operator's maintenance or
inspection program without obtaining approval of an AMOC; this is provided that the
steps between RC Start and RC End, including sub-steps and identified figures, can
still be done as specified, and the airplane can be put back in an airworthy condition.
Figures not required for compliance are omitted from the RB.
12. This is an Enhanced Required for Compliance document. The Boeing processes
used to create the Service Bulletin (SB) and the Requirements Bulletin (RB) ensure
that the information between "RC Start" and "RC End" in the SB are identical to the
information in the same sections (Compliance, Work Instructions...) of the RB which
the SB refers to as the related document.
B. WORK INSTRUCTIONS
Actions Required for Compliance:
1. Requirements
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
14 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 15

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
Do PART 1: OPEN
ACCESS
-ACTION 1: Do the surface HFEC
inspections of the lower sill splice
plate at S-15, in the inspection
area at STA 601 and STA 616,
on the left side, for any crack and
any severed splice plate.
All airplanes.
-FIGURE 1
Do PART 1: OPEN
ACCESS
-ACTION 2: Do the surface HFEC
inspections of the lower sill splice
plate at S-15, in the inspection
area at STA 601 and STA 616,
on the right side, for any crack
and any severed splice plate.
-FIGURE 2
-FIGURE 3CONDITION 1 (ACTION 1): Do
the splice plate replacement on
the left side.
CONDITION 1: ANY
CRACK FOUND IN THE
LEFT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 1 (ACTION 2): Re-
peat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
-FIGURE 5 and FIGURE 9Do the open hole HFEC inspec-
tions at STA 601, surface HFEC
inspection of the skin and a de-
tailed inspection of the structure
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack.
CONDITION 2: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 601
INSPECTION AREA ON
THE LEFT SIDE (a)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
15 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 16

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
--CONDITION 2.1 (ACTION 1):
Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 2.1: ANY
CRACK FOUND
-FIGURE 3CONDITION 2.1 (ACTION 2): Do
the splice plate replacement on
the left side. Do PART 2:CLOSE ACCESS-
Do PART 1: OPEN
ACCESS
-CONDITION 2.1 (ACTION 3):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
-FIGURE 3CONDITION 2.2 (ACTION 1): Do
the splice plate replacement on
the left side.
CONDITION 2.2: NO
CRACK FOUND Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 2.2 (ACTION 2):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
-FIGURE 6 and FIGURE 9Do the open hole HFEC inspec-
tions at STA 616, surface HFEC
inspection of the skin and a de-
tailed inspection of the structure
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack.
CONDITION 3: SPLICE
PLATE SEVERED IN THE
STA 616 INSPECTION
AREA ON THE LEFT SIDE
(a)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
16 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 17

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
--CONDITION 3.1 (ACTION 1):
Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 3.1: ANY
CRACK FOUND
-FIGURE 3CONDITION 3.1 (ACTION 2): Do
the splice plate replacement on
the left side. Do PART 2:CLOSE ACCESS-
Do PART 1: OPEN
ACCESS
-CONDITION 3.1 (ACTION 3):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
-FIGURE 3CONDITION 3.2 (ACTION 1): Do
the splice plate replacement on
the left side.
CONDITION 3.2: NO
CRACK FOUND Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 3.2 (ACTION 2):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
left side, for any crack and any
severed splice plate.
CONDITION 4: NO
CRACK FOUND IN THE
LEFT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
-FIGURE 1
Do PART 2:
CLOSE ACCESS
-
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
17 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 18

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
-FIGURE 4CONDITION 5 (ACTION 1): Do
the splice plate replacement on
the right side.
CONDITION 5: ANY
CRACK FOUND IN THE
RIGHT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 5 (ACTION 2): Re-
peat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
-FIGURE 7 and FIGURE 10Do the open hole HFEC inspec-
tions at STA 601, surface HFEC
inspection of the skin and a de-
tailed inspection of the structure
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack.
CONDITION 6: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 601
INSPECTION AREA ON
THE RIGHT SIDE (a)
--CONDITION 6.1 (ACTION 1):
Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 6.1: ANY
CRACK FOUND (a)
-FIGURE 4CONDITION 6.1 (ACTION 2): Do
the splice plate replacement on
the right side. Do PART 2:CLOSE ACCESS-
Do PART 1: OPEN
ACCESS
-CONDITION 6.1 (ACTION 3):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
18 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 19

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
-FIGURE 4CONDITION 6.2 (ACTION 1): Do
the splice plate replacement on
the right side.
CONDITION 6.2: NO
CRACK FOUND Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 6.2 (ACTION 2):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
-FIGURE 8 and FIGURE 10Do the open hole HFEC inspec-
tions at STA 616, surface HFEC
inspection of the skin and a de-
tailed inspection of the structure
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack.
CONDITION 7: SPLICE
PLATE IS FOUND SEV-
ERED IN THE STA 616
INSPECTION AREA ON
THE RIGHT SIDE (a)
--CONDITION 7.1 (ACTION 1):
Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 7.1: ANY
CRACK FOUND
-FIGURE 4CONDITION 7.1 (ACTION 2): Do
the splice plate replacement on
the right side. Do PART 2:CLOSE ACCESS-
Do PART 1: OPEN
ACCESS
-CONDITION 7.1 (ACTION 3):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
19 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 20

TABLE 1: SURFACE HFEC INSPECTION OF THE LOWER SILL SPLICE PLATE AT S-15, IN THE INSPEC-
TION AREA AT STA 601 AND STA 616, LEFT AND RIGHT SIDE
Refer to the listed
procedures in SB
737-53A1380
Original Issue or
later approved re-
visions as an ac-
cepted proce-
dure:
Method of ComplianceActionCondition
-FIGURE 4CONDITION 7.2 (ACTION 1): Do
the splice plate replacement on
the right side.
CONDITION 7.2: NO
CRACK FOUND Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-CONDITION 7.2 (ACTION 2):
Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
Do PART 1: OPEN
ACCESS
-Repeat the surface HFEC inspec-
tions of the lower sill splice plate
at S-15, in the inspection area at
STA 601 and STA 616, on the
right side, for any crack and any
severed splice plate.
CONDITION 8: NO
CRACK FOUND IN THE
RIGHT SIDE SPLICE
PLATE AND THE SPLICE
PLATE IS NOT SEVERED
(a)
-FIGURE 2
Do PART 2:
CLOSE ACCESS
-
(a) More than one CONDITION can be applicable.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
20 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 21 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
STA  EXITS
STA 639
578
D D0в0009
S-10L
STA
578
STA
601
S-15L'  SIA  616
STA  2813124
639
FIGURE 1: LEFT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  21 of 46

### Page 22 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
FRAME
STA  STA  SKIN
LOWER SILL  616  601
S-15L
S-16L
SPLICE PLATE
CLIPS  CLIPS
FWD
A-A
1 5 LOCATIONS
STA
SPLICE PLATE  601
S-15L
FRAME
TYPICAL CRACK
STA 601 INSPECTION AREA SHOWN
STA 616 INSPECTION AREA SIMILAR
SURFACE HFEC INSPECTION
2813125
FIGURE 1: LEFT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 2 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  22 of 46

### Page 23

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1-Splice plateInspect1
(a) Do a surface High Frequency Eddy Current (HFEC) inspection of the splice plate around each fastener
in the inspection area, in accordance with 737 NDT Manual Part 6, 51-00-00 Procedure 4 or Procedure
23 for any crack and any severed splice plate. Use a HFEC pencil probe with a 0.05 inch or smaller outer
diameter probe.
FIGURE 1: LEFT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
23 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 24 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
EXITS
STA
639 STA
578
000007
S-10R
STA
601
STA
616  S-15R
2813154
FIGURE 2: RIGHT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  24 of 46

### Page 25 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
FRAME
STA  STA  SKIN
LOWER SILL  601  616
S-15R  6=+-  • OH
S-16R
CLIPS  CLIPS  SPLICE PLATE
FWD
A-A
) 5 LOCATIONS
SPLICE PLATE
S-15R-
FRAME
TYPICAL CRACK
STA 616 INSPECTION AREA SHOWN,
STA 601 INSPECTION AREA SIMILAR
N SURFACE HFEC INSPECTION
2813157
FIGURE 2: RIGHT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 2 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1380 RB
Work - See page 1 for details.  25 of 46

### Page 26

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1-Splice plateInspect1
(a) Do a surface High Frequency Eddy Current (HFEC) inspection of the splice plate around each fastener
in the inspection area, in accordance with 737 NDT Manual Part 6, 51-00-00 Procedure 4 or Procedure
23 for any crack and any severed splice plate. Use a HFEC pencil probe with a 0.05 inch or smaller outer
diameter probe.
FIGURE 2: RIGHT SIDE - LOWER SILL SPLICE PLATE S-15, STA 601 AND STA 616 - SURFACE HFEC
INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
26 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 27 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
EXITS
STA
STA 639
578
D D0в0009
S-10L
STA
578
STA
601
S-15L
STA  2813171
639
FIGURE 3: LEFT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1380 RB
Work - See page 1 for details.  27 of 46

### Page 28

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)27-FastenerRemove1
(b)1-Lower sillInspect2
(c)165C33084-5Splice plateLocate3
(d)165C33084-5Splice plateDrill4
-165C33084-5Splice plateRemove / Keep5
(e)(f)(g)165C33084-5Splice plateDeburr6
(h)(i)165C33084-5Splice plateInstall (New)7
(a) Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection at all locations where a fastener was removed for any crack in accor-
dance with 737 NDT Manual Part 6, 51-00-00 Procedure 16. Make sure the inspection area is crack free
before the new splice plate is installed. If any crack is found contact The Boeing Company for repair in-
structions and do the repair.
(c) Locate the new splice plate to match the position of the removed splice plate.
(d) Back drill through existing holes. Maintain a minimum of 1.7D edge margin on all structure common to
the holes.
(e) Deburr and remove all sharp edges.
(f) Apply chemical conversion coating to any bare metal surface as required during splice plate replacement
in accordance with 737-400 SRM 51-20-01.
FIGURE 3: LEFT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 2 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
28 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 29

More DataQtyIdentificationNameTaskStep
(g) Apply two coats of BMS 10-11 Type I primer to any exposed alodine surface of the sill during splice plate
replacement. Refer to SOPM 20-41-02 as an accepted procedure.
(h) Apply faying surface sealant on all mating parts. Refer to SOPM 20-50-19 as an accepted procedure.
(i) Refer to fastener code table for fastener installation.
The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the
number of fasteners necessary for this figure.
More DataHole DiaQtyIdentificationNameCode
(a)-27BACR15FT6D()CRIVETA
(a) It is acceptable to oversize fasteners up to 1/32 inch to meet the hole filling requirement. Refer to 737-400
SRM 51-40-02 as an accepted procedure. For hole size limits refer to 737-400 SRM 51-40-05.
FIGURE 3: LEFT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
29 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 30 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
EXITS
STA
639 STA
578
0005007
S-10R
STA
601
STA
616  S-15R
2813375
FIGURE 4: RIGHT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  30 of 46

### Page 31

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)27-FastenerRemove1
(b)1-Lower sillInspect2
(c)165C33084-5Splice plateLocate3
(d)165C33084-5Splice plateDrill4
-165C33084-5Splice plateRemove / Keep5
(e)(f)(g)165C33084-5Splice plateDeburr6
(h)(i)165C33084-5Splice plateInstall (New)7
(a) Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection at all locations where a fastener was removed for any crack in accor-
dance with 737 NDT Manual Part 6, 51-00-00 Procedure 16. Make sure the inspection area is crack free
before the new splice plate is installed. If any crack is found contact The Boeing Company for repair in-
structions and do the repair.
(c) Locate the new splice plate to match the position of the removed splice plate.
(d) Back drill through existing holes. Maintain a minimum of 1.7D edge margin on all structure common to
the holes.
(e) Deburr and remove all sharp edges.
(f) Apply chemical conversion coating to any bare metal surface as required during splice plate replacement
in accordance with 737-400 SRM 51-20-01.
FIGURE 4: RIGHT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 2 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
31 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 32

More DataQtyIdentificationNameTaskStep
(g) Apply two coats of BMS 10-11 Type I primer to any exposed alodine surface of the sill during splice plate
replacement. Refer to SOPM 20-41-02 as an accepted procedure.
(h) Apply faying surface sealant on all mating parts. Refer to SOPM 20-50-19 as an accepted procedure.
(i) Refer to fastener code table for fastener installation.
The codes shown below agree with the letter shown in the upper left corner of the fastener symbols in the figure.
A number in the lower right corner gives the grip length of the fastener. The QTY numbers shown below are the
number of fasteners necessary for this figure.
More DataHole DiaQtyIdentificationNameCode
(a)-27BACR15FT6D()CRIVETA
(a) It is acceptable to oversize fasteners up to 1/32 inch to meet the hole filling requirement. Refer to 737-400
SRM 51-40-02 as an accepted procedure. For hole size limits refer to 737-400 SRM 51-40-05.
FIGURE 4: RIGHT SIDE LOWER SILL SPLICE PLATE - REPLACEMENT
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
32 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 33 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
STA
STA 616
601
STA  616  OVERWING  EMERGENCY EXIT
FRAME
STA  FRAME  - S-15L
OVERWING  601  OUTER
EMERGENCY EXIT  CHORD
SPLICE PLATE
LOWER SILL
(2)  4
LOWER SILL
OUTER
CHORD  SKIN
HFEC INSPECTION
2813379
FIGURE 5: LEFT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 1 OF 2)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  33 of 46

### Page 34

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2-FastenerRemove1
(b)--Lower sill outer chordInspect2
(b)--SkinInspect
(b)--Frame outer chordInspect
(c)--SkinInspect3
(d)(e)2BACB30NW8K()BOLTInstall (New)4
(d)(e)2BACC30MCOLLARInstall (New)
(a) Remove the two fasteners common to the STA 601 lower sill outer chord, frame outer chord and skin.
Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00
Procedure 16.
(c) Do a surface HFEC inspection of the skin from seven fastener rows forward of STA 601 to seven fastener
rows aft of STA 616 around each fastener head for any crack in accordance with 737 NDT Manual Part
6, 51-00-00 Procedure 4 or Procedure 23.
(d) If no crack is found, install fasteners in transition fit holes; refer to 737-400 SRM 51-40-02 as an accepted
procedure. It is acceptable to oversize the fastener up to 1/64 inch. For hole size limits, refer to 737-400
SRM 51-40-05 as an accepted procedure.
(e) Install fasteners wet with BMS 5-95, Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted
procedure.
FIGURE 5: LEFT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
34 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 35 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
STA
STA 616  601  0000..00
STA  616  OVERWING  EMERGENCY EXIT
FRAME
STA  FRAME  -S-15L
OVERWING  601  OUTER
EMERGENCY EXIT  CHORD
SPLICE PLATE  • 919|41118{191111411914141  44141919191415  1441914141919100
LOWER SILL
LOWER SILL
OUTER
CHORD  SKIN
HFEC INSPECTION
2813382
FIGURE 6: LEFT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTION
OF THE SKIN
(SHEET 1 OF 2)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  35 of 46

### Page 36

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2-FastenerRemove1
(b)--Lower sill outer chordInspect2
(b)--SkinInspect
(b)--Frame outer chordInspect
(c)--SkinInspect3
(d)(e)2BACB30NW8K()BOLTInstall (New)4
(d)(e)2BACC30MCOLLARInstall (New)
(a) Remove the two fasteners common to the STA 616 lower sill outer chord, frame outer chord and skin.
Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00
Procedure 16.
(c) Do a surface HFEC inspection of the skin from seven fastener rows forward of STA 601 to seven fastener
rows aft of STA 616 around each fastener head for any crack in accordance with 737 NDT Manual Part
6, 51-00-00 Procedure 4 or Procedure 23.
(d) If no crack is found, install fasteners in transition fit holes; refer to 737-400 SRM 51-40-02 as an accepted
procedure. It is acceptable to oversize the fastener up to 1/64 inch. For hole size limits, refer to 737-400
SRM 51-40-05 as an accepted procedure.
(e) Install fasteners wet with BMS 5-95, Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted
procedure.
FIGURE 6: LEFT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTION
OF THE SKIN
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
36 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 37 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
STA
616 STA
601
OVERWING  EMERGENCY EXIT  STA  616  00000000
FRAME
S-15R_  FRAME  STA
OUTER  601  OVERWING
CHORD  EMERGENCY EXIT
SPLICE PLATE
LOWER SILL
LOWER SILL
OUTER
SKIN  CHORD
2813385
FIGURE 7: RIGHT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 1 OF 2)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  37 of 46

### Page 38

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2-FastenerRemove1
(b)--Lower sill outer chordInspect2
(b)--SkinInspect
(b)--Frame outer chordInspect
(c)--SkinInspect3
(d)(e)2BACB30NW8K()BOLTInstall (New)4
(d)(e)2BACC30MCOLLARInstall (New)
(a) Remove the two fasteners common to the STA 601 lower sill outer chord, frame outer chord and skin.
Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00
Procedure 16.
(c) Do a surface HFEC inspection of the skin from seven fastener rows forward of STA 601 to seven fastener
rows aft of STA 616 around each fastener head for any crack in accordance with 737 NDT Manual Part
6, 51-00-00 Procedure 4 or Procedure 23.
(d) If no crack is found, install fasteners in transition fit holes; refer to 737-400 SRM 51-40-02 as an accepted
procedure. It is acceptable to oversize the fastener up to 1/64 inch. For hole size limits, refer to 737-400
SRM 51-40-05 as an accepted procedure.
(e) Install fasteners wet with BMS 5-95, Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted
procedure.
FIGURE 7: RIGHT SIDE - STA 601 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
38 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 39 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
STA
616 STA
601
OVERWING  EMERGENCY EXIT  STA  616
FRAME
S-15R.
FRAME  STA
OUTER  601  OVERWING
CHORD  EMERGENCY EXIT
SPLICE PLATE
LOWER SILL
LOWER SILL
OUTER
SKIN  CHORD
2813388
FIGURE 8: RIGHT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 1 OF 2)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  39 of 46

### Page 40

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2-FastenerRemove1
(b)--Lower sill outer chordInspect2
(b)--SkinInspect
(b)--Frame outer chordInspect
(c)--SkinInspect3
(d)(e)2BACB30NW8K()BOLTInstall (New)4
(d)(e)2BACC30MCOLLARInstall (New)
(a) Remove the two fasteners common to the STA 616 lower sill outer chord, frame outer chord and skin.
Refer to 737-400 SRM 51-40-02 as an accepted procedure.
(b) Do an open hole HFEC inspection for any crack in accordance with 737 NDT Manual Part 6, 51-00-00
Procedure 16.
(c) Do a surface HFEC inspection of the skin between seven fastener rows forward of STA 601 to seven
fastener rows aft of STA 616 around each fastener head for any crack in accordance with 737 NDT
Manual Part 6, 51-00-00 Procedure 4 or Procedure 23.
(d) If no crack is found, install fasteners in transition fit holes; refer to 737-400 SRM 51-40-02 as an accepted
procedure. It is acceptable to oversize the fastener up to 1/64 inch. For hole size limits, refer to 737-400
SRM 51-40-05 as an accepted procedure.
(e) Install fasteners wet with BMS 5-95, Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted
procedure.
FIGURE 8: RIGHT SIDE - STA 616 OPEN HOLE HFEC INSPECTION AND SURFACE HFEC INSPECTIONS
OF THE SKIN
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
40 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 41 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
EXITS
STA
STA 639
578
D D0в0009
S-10L
STA
578
STA
601
SIA
S-15L  616
STA  2813391
639
FIGURE 9: LEFT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  41 of 46

### Page 42 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
FRAME  STA
STA  601  SKIN
LOWER SILL  616
B
...
S-15L  Ei-
S-16L
CLIPS  CLIPS  SPLICE PLATE
FWD
A-A
FRAME  FRAME
OUTER  OUTER
CHORD  SKIN  LOWER SILL  CHORD
STA  616  ) CLIPS  CLIPS (2  STA  601
SPLICE PLATE
FWD
DETAILED INSPECTION
VIEW LOOKING DOWN
B-B  2813392
FIGURE 9: LEFT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 2 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1380 RB
Work - See page 1 for details.  42 of 46

### Page 43

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)--Lower sillInspect1
(b)4-ClipInspect2
(a) Do a detailed inspection of the lower sill including the lower sill common to the attached clips at STA 601
and STA 616 for any crack.
(b) Do a detailed inspection of the clips that attach the lower sill to the frame at STA 601 and STA 616 for
any crack.
FIGURE 9: LEFT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
43 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

### Page 44 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
OVERWING
EMERGENCY
EXITS
STA
639 STA
578
0005007
S-10R
STA
601
STA
616  S-15R
2813405
FIGURE 10: RIGHT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 1 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  44 of 46

### Page 45 (OCR)

REQUIREMENTS BULLETIN 737-53A1380
ALERT  ALERT
FRAME  STA
STA  616  SKIN
601
LOWER SILL
B
S-15R
S-16R
SPLICE PLATE
FWD
CLIPS  CLIPS
A-A
FRAME  FRAME
OUTER  OUTER
CHORD  SKIN  CHORD
LOWER SILL
STA  601  2) CLIPS  CLIPS (2  STA  616
• SPLICE PLATE
FWD
ЛЛ DETAILED INSPECTION
VIEW LOOKING DOWN  B-B  2813407
FIGURE 10: RIGHT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 2 OF 3)
Original Issue: July 18, 2018
Export Controlled ECCN: 9E991  737-53A1380 RB
Copyright © Unpublished
Work - See page 1 for details.  45 of 46

### Page 46

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)--Lower sillInspect1
(b)4-ClipInspect2
(a) Do a detailed inspection of the lower sill including the lower sill common to the attached clips at STA 601
and STA 616 for any crack.
(b) Do a detailed inspection of the clips that attach the lower sill to the frame at STA 601 and STA 616 for
any crack.
FIGURE 10: RIGHT SIDE - LOWER SILL AND CLIP - DETAILED INSPECTION
(SHEET 3 OF 3)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 18, 2018
737-53A1380 RB
46 of 46
REQUIREMENTS BULLETIN 737-53A1380
ALERTALERT

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.