# Boeing Alert Requirements Bulletin A3544 RB: No revision named

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- Title as filed: A3544 RB
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### Page 1

Commercial 
Airplanes
707
Requirements Bulletin
ALERT
Number: A3544 RB
Original Issue: November 01, 2021
ATA System: 5706
SUBJECT: WINGS - Center Section - Lower Skin and Rear Spar Lower Chord between LBBL 40
and RBBL 40 - 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 © 2021 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Unpublished Work.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
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connection with this document unless provided in writing by Boeing.
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5.0

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Table of Contents
1 . E F F E C T I V I T Y  ................................................ 5
A . A i r p l a n e s  ................................................ 5
B . S p a r e s  A f f e c t e d  ............................................ 7
2. CONCURRENT REQUIREMENTS ..................................... 7
3 . C O M P L I A N C E  ................................................ 7
4. APPROVAL ................................................ 1 3
5. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 5
A. General Information ......................................... 1 5
B. Work Instructions ........................................... 1 6
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION . 19
FIGURE 3: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - SEALANT
APPLICATION ......................................... 2 4
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### Page 5

Commercial 
Airplanes
707
Requirements Bulletin
ALERT
Number: A3544 RB
Original Issue: November 01, 2021
ATA System: 5706
SUBJECT: WINGS - Center Section - Lower Skin and Rear Spar Lower Chord between LBBL 40
and RBBL 40 - 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 707-100 LONG BODY, 707-100B LONG BODY, 707-100B SHORT
BODY, 707-200, 707-300, 707-300B, 707-300C, 707-400 Airplane(s), line number(s) 1-2, 4-7,
9-35, 37-84, 86-94, 96-108, 110-118, 121-129, 133-140, 144-145, 151-155, 159-164, 167-171,
175-176, 192, 200-201, 205, 209, 212, 216-217, 227-229, 264, 266, 268-272, 274-277, 280,
282-283, 286-287, 291-294, 296, 299, 301-303, 305-306, 308-309, 311-313, 315-318, 320, 323,
325-336, 341-346, 348-350, 352-360, 362-373, 375-379, 383, 385-389, 391-400, 402-409, 411-413,
415-422, 424-426, 428, 430-432, 434-441, 443-469, 471-472, 475-480, 482-511, 513, 515-580,
582-596, 598-614, 616-620, 622-623, 625-770, 772-776, 778-786, 788-793, 795-800, 802-855,
857, 859-897, 899-900, 903, 905-906, 908, 910-912, 914-915, 917-919, 922-923, 925, 928-929,
936, 938, 941 in 4 Group(s). Where the effectivity is presented with hyphens between line numbers,
the airplane applicability means "through" and "inclusive", e.g. line numbers 1-9 means line numbers
1 through 9 inclusive.
The Variable Numbers and Group Information for the applicable airplanes is given below.
DESCRIPTIONCONFIGURATIONGROUP
707-100 LONG BODY, -100B LONG BODY, -100B SHORT BODY,
-200 Airplanes
-1
707-300/-400 Airplanes-2
707-300B Airplanes-3
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DESCRIPTIONCONFIGURATIONGROUP
707-300C Airplanes-4
Passenger Airplanes1
Cargo Airplanes2
Airplane Models:
707-100 LONG BODY, 707-100B LONG BODY, 707-100B SHORT BODY, 707-200, 707-300,
707-300B, 707-300C, 707-400
GroupVariable Number
100001 - 00002
100004 - 00006
100101
100103 - 00113
100115 - 00153
100201 - 00205
100301 - 00305
100401 - 00449
100471 - 00475
100501 - 00513
100601
100701 - 00703
202001 - 02020
202101 - 02121
202201 - 02207
202301 - 02303
202401 - 02418
204001 - 04005
204020 - 04022
204101 - 04106
204201 - 04218
204271 - 04272
204301 - 04303
GroupVariable Number
305001 - 05060
305101 - 05138
305201 - 05208
305301 - 05312
305401
305601 - 05605
305631 - 05635
305701 - 05703
305801 - 05802
305821 - 05827
305831 - 05833
305851 - 05854
305891 - 05892
305921 - 05923
305941 - 05942
305961 - 05970
306001 - 06002
306101
306401 - 06404
306451
306461
407001 - 07017
407041 - 07059
GroupVariable Number
407071 - 07081
407101 - 07109
407181
407191
407201 - 07215
407251 - 07271
407401 - 07407
407451 - 07458
407501 - 07504
407601 - 07626
407661 - 07662
407681 - 07684
407701 - 07702
407801 - 07821
407901 - 07907
408001 - 08008
408021
408051 - 08056
408071 - 08077
408101 - 08104
408121 - 08129
408141 - 08144
408151 - 08153
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GroupVariable Number
408171 - 08173
408191 - 08192
408201 - 08210
408221 - 08224
408241 - 08244
408251
408261
408271
408301 - 08320
408324 - 08330
408333
GroupVariable Number
408401 - 08410
408451 - 08452
408471 - 08475
408501 - 08502
408551 - 08553
408581 - 08582
409001 - 09006
409101 - 09107
409161 - 09167
409201 - 09204
409221 - 09223
GroupVariable Number
409227
409231 - 09232
409251
409271
409281
409286 - 09290
409411
409421
409438
409441
--
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 707A3544 RB. The Airworthiness Directive will make the compliance tasks and times
given in Requirements Bulletin 707A3544 RB mandatory.
Group 1: Accomplish the required action(s), based on the applicable condition(s) in Table 1, in accordance
with Accomplishment Instructions.
Group 2: Accomplish the required action(s), based on the applicable condition(s) in Table 2, in accordance
with Accomplishment Instructions.
Group 3: Accomplish the required action(s), based on the applicable condition(s) in Table 3, in accordance
with Accomplishment Instructions.
Group 4: Accomplish the required action(s), based on the applicable condition(s) in Table 4, 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.
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Group 1:
Table 1: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 2,100
flight cycles af-
ter the original
issue date of
Requirements
Bulletin
707A3544 RB.
Before 15,000
total flight cy-
cles.
Do an internal Detailed In-
spection of the center wing
box lower skin between
LBBL 40 and RBBL 40, do
an internal surface High
Frequency Eddy Current
(HFEC) Inspection and an
internal Ultrasonic (UT) In-
spection of the rear spar
lower chord located be-
tween LBBL 40 and RBBL
40 for any crack.
All airplanes.
-Before further flight.CONDITION 1 (ACTION 1):
Apply sealant.
CONDITION 1: NO
CRACK FOUND.
4,400 flight cy-
cles
-CONDITION 1 (ACTION 2):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack. (a)
--Before further
flight.
CONDITION 2 (ACTION 1):
Contact the Boeing Compa-
ny for repair instructions
and do the repair.
CONDITION 2: ANY
CRACK FOUND.
CONDITION 2 (ACTION 2):
Apply sealant.
4,400 flight cy-
cles
-CONDITION 2 (ACTION 3):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack at
the unrepaired areas. (a)
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Group 1:
Table 1: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
(a) It is not required to do the inspection in areas where a repair covers the affected inspection area if the
repair meets the conditions that follow:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin
707A3544 RB and installed after the original issue date of Requirements Bulletin 707A3544
RB.
2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA)
via a FAA Form 8100-9.
Group 2:
Table 2: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 2,100
flight cycles af-
ter the original
issue date of
Requirements
Bulletin
707A3544 RB.
Before 15,000
total flight cy-
cles.
Do an internal Detailed In-
spection of the center wing
box lower skin between
LBBL 40 and RBBL 40, do
an internal surface High
Frequency Eddy Current
(HFEC) Inspection and an
internal Ultrasonic (UT) In-
spection of the rear spar
lower chord located be-
tween LBBL 40 and RBBL
40 for any crack.
All airplanes.
-Before further flight.CONDITION 1 (ACTION 1):
Apply sealant.
CONDITION 1: NO
CRACK FOUND.
5,700 flight cy-
cles
-CONDITION 1 (ACTION 2):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack. (a)
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Group 2:
Table 2: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
--Before further
flight.
CONDITION 2 (ACTION 1):
Contact the Boeing Compa-
ny for repair instructions
and do the repair.
CONDITION 2: ANY
CRACK FOUND.
CONDITION 2 (ACTION 2):
Apply sealant.
5,700 flight cy-
cles
-CONDITION 2 (ACTION 3):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack at
the unrepaired areas. (a)
(a) It is not required to do the inspection in areas where a repair covers the affected inspection area if the
repair meets the conditions that follow:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin
707A3544 RB and installed after the original issue date of Requirements Bulletin 707A3544
RB.
2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA)
via a FAA Form 8100-9.
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Group 3; Group 4, Configuration 1:
Table 3: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 2,100
flight cycles af-
ter the original
issue date of
Requirements
Bulletin
707A3544 RB.
Before 15,000
total flight cy-
cles.
Do an internal Detailed In-
spection of the center wing
box lower skin between
LBBL 40 and RBBL 40, do
an internal surface High
Frequency Eddy Current
(HFEC) Inspection and an
internal Ultrasonic (UT) In-
spection of the rear spar
lower chord located be-
tween LBBL 40 and RBBL
40 for any crack.
All airplanes.
-Before further flight.CONDITION 1 (ACTION 1):
Apply sealant.
CONDITION 1: NO
CRACK FOUND.
5,000 flight cy-
cles
-CONDITION 1 (ACTION 2):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack. (a)
--Before further
flight.
CONDITION 2 (ACTION 1):
Contact the Boeing Compa-
ny for repair instructions
and do the repair.
CONDITION 2: ANY
CRACK FOUND.
CONDITION 2 (ACTION 2):
Apply sealant.
5,000 flight cy-
cles
-CONDITION 2 (ACTION 3):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack at
the unrepaired areas. (a)
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### Page 12

Group 3; Group 4, Configuration 1:
Table 3: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
(a) It is not required to do the inspection in areas where a repair covers the affected inspection area if the
repair meets the conditions that follow:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin
707A3544 RB and installed after the original issue date of Requirements Bulletin 707A3544
RB.
2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA)
via a FAA Form 8100-9.
Group 4, Configuration 2:
Table 4: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 2,100
flight cycles af-
ter the original
issue date of
Requirements
Bulletin
707A3544 RB.
Before 15,000
total flight cy-
cles.
Do an internal Detailed In-
spection of the center wing
box lower skin between
LBBL 40 and RBBL 40, do
an internal surface High
Frequency Eddy Current
(HFEC) Inspection and an
internal Ultrasonic (UT) In-
spection of the rear spar
lower chord located be-
tween LBBL 40 and RBBL
40 for any crack.
All airplanes.
-Before further flight.CONDITION 1 (ACTION 1):
Apply sealant.
CONDITION 1: NO
CRACK FOUND.
2,200 flight cy-
cles
-CONDITION 1 (ACTION 2):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack. (a)
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### Page 13

Group 4, Configuration 2:
Table 4: Center Wing Box, Rear Spar Lower Chord and Lower Skin Between LBBL 40 and RBBL 40, In-
spection.
Repeat Interval
(Not to Exceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
--Before further
flight.
CONDITION 2 (ACTION 1):
Contact the Boeing Compa-
ny for repair instructions
and do the repair.
CONDITION 2: ANY
CRACK FOUND.
CONDITION 2 (ACTION 2):
Apply sealant.
2,200 flight cy-
cles
-CONDITION 2 (ACTION 3):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack at
the unrepaired areas. (a)
(a) It is not required to do the inspection in areas where a repair covers the affected inspection area if the
repair meets the conditions that follow:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin
707A3544 RB and installed after the original issue date of Requirements Bulletin 707A3544
RB.
2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA)
via a FAA Form 8100-9.
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
Union Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved
airplanes listed in this Requirements 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.
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### Page 15

5.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
NOTE: 1. 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.
2. 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.
3. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance.
4. Boeing Service Letter 707-SL-51-029, 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.
5. 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 707 Structural Repair Manual,
Chapter 51.
— Values of airframe maintenance tasks are included in Chapter 13 of 707
Aircraft Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
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6. 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.
7. 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.
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. Use the approved fastener, process and material substitutions in accordance with
SRM Chapter 51.
10. A Detailed Inspection is defined as: An intensive examination of a specific item,
installation or assembly to detect damage, failure or irregularity. This could include
tactile assessment in which a component or assembly can be checked for
tightness/security. Available lighting is normally supplemented with a direct source
of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors
and magnifying lenses may be necessary. Surface cleaning and elaborate access
procedures may be required.
11. 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.
B. WORK INSTRUCTIONS
Actions Required For Compliance
1. Requirements.
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### Page 17

Table 1 (Related to all Compliance Tables): Center Wing Box, Rear Spar Lower Chord and Lower Skin
Between LBBL 40 and RBBL 40, Inspection.
Refer to the list-
ed procedures
in SB 707A3544
Original Issue
or later ap-
proved revi-
sions as an ac-
cepted proce-
dure.
Method of ComplianceActionCondition
PART 1: OPEN
ACCESS
-Do an internal Detailed In-
spection of the center wing
box lower skin between
LBBL 40 and RBBL 40, do
an internal surface High
Frequency Eddy Current
(HFEC) Inspection and an
internal Ultrasonic (UT) In-
spection of the rear spar
lower chord located be-
tween LBBL 40 and RBBL
40 for any crack.
All airplanes.
FIGURE 1-
-FIGURE 2
-FIGURE 3CONDITION 1 (ACTION 1):
Apply sealant.
CONDITION 1: NO
CRACK FOUND. PART 2: CLOSE
ACCESS
-
PART 1: OPEN
ACCESS
-CONDITION 1 (ACTION 2):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack. (a)
FIGURE 1-
-FIGURE 2
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A3544 RB
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REQUIREMENTS BULLETIN A3544
ALERTALERT

### Page 18

Table 1 (Related to all Compliance Tables): Center Wing Box, Rear Spar Lower Chord and Lower Skin
Between LBBL 40 and RBBL 40, Inspection.
Refer to the list-
ed procedures
in SB 707A3544
Original Issue
or later ap-
proved revi-
sions as an ac-
cepted proce-
dure.
Method of ComplianceActionCondition
--CONDITION 2 (ACTION 1):
Contact the Boeing Compa-
ny for repair instructions
and do the repair.
CONDITION 2: ANY
CRACK FOUND.
-FIGURE 3CONDITION 2 (ACTION 2):
Apply sealant. PART 2: CLOSE
ACCESS
PART 1: OPEN
ACCESS
-CONDITION 2 (ACTION 3):
Repeat internal Detailed
Inspection of the lower skin
and internal surface HFEC
and UT Inspection of the
rear spar lower chord locat-
ed between LBBL 40 and
RBBL 40 for any crack at
the unrepaired areas. (a)
FIGURE 1-
-FIGURE 2
(a) It is not required to do the inspection in areas where a repair covers the affected inspection area if the
repair meets the conditions that follow:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin
707A3544 RB and installed after the original issue date of Requirements Bulletin 707A3544
RB.
2. The installed repair was approved by the Boeing Organization Designation Authorization (ODA)
via a FAA Form 8100-9.
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A3544 RB
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REQUIREMENTS BULLETIN A3544
ALERTALERT

### Page 19 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
AFT FUEL CELL
STA
820
SEPAR
RBBL  LBBL
REAR SPAR  34.00  34.00  REAR SPAR
WEB  RBBL  RBBL  RBBL  LBBL  LBBL  LOWER CHORD
40.00  24.85  12.88  12.88  24.85  40.00
VAPOR BARRIER SEAL  LOWER SKIN
WING CENTER SECTION REAR SPAR
(VIEW LOOKING AFT)
(STIFFENER LAYOUT, STIFFENER SUPPORT BRACKET ORIENTATION
AND BUTTOCK STATIONS MAY NOT BE EXACTLY AS SHOWN)  2972274
A-A
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION
(SHEET 1 OF 5)
Original Issue: November 01, 2021
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Work - See page 1 for details.  19 of 27

### Page 20 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
STIFFENER  LBBL
SUPPORT  REAR SPAR  40.00
BRACKET  TYPICAL  LOWER CHORD  REF
BBL  LBBL  CRACK  TYPICAL  LBBL
0.00  12.88  CRACK  42.20
REAR
SPAR
PLANE
2.00
MINIMUM
LOWER  SKIN  CRACK  TYPICAL  0.10 MAXIMUM  FROM EDGE OF  STIFFENER  STIFFENER
SUPPORT  SUPPORT
BRACKET  BRACKET
RBBL  RBBL  40.00  REF  LOWER CHORD  REAR SPAR  CRACK  TYPICAL  STIFFENER  SUPPORT  BRACKET  RBBL  12.88  TYPICAL  CRACK  BBL
42.20  0.00
REAR
SPAR
PLANE
2.00
MINIMUM
STIFFENER  0.10 MAXIMUM  FROM EDGE OF STIFFENER  SUPPORT BRACKET  D  TYPICAL  CRACK  LOWER  SKIN
SUPPORT
BRACKET
REAR SPAR LOWER CHORD AND LOWER SKIN
(VIEW LOOKING DOWN)
(STIFFENER SUPPORT BRACKET ORIENTATION, BUTTOCK STATIONS
AND FASTENER LOCATIONS MAY NOT BE EXACTLY AS SHOWN)
B-B
INTERNAL DETAILED INSPECTION
INTERNAL SURFACE HIGH FREQUENCY EDDY CURRENT INSPECTION  INTERNAL ULTRASONIC INSPECTION  2972275
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION
(SHEET 2 OF 5)
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### Page 21 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
REAR SPAR  TYPICAL
LOWER CHORD  CHORD CRACK
REAR SPAR PLANE
LOWER CHORD-
2.0 MINIMUM
TYPICAL SKIN
LOWER SKIN  CRACK
VIEW LOOKING DOWN
INTERNAL DETAILED INSPECTION
INTERNAL SURFACE HIGH FREQUENCY EDDY CURRENT INSPECTION  2982257
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION
(SHEET 3 OF 5)
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Work - See page 1 for details.  21 of 27

### Page 22 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
INTERNAL DETAILED  • REAR SPAR PLANE
INSPECTION
• REAR SPAR WEB
INTERNAL SURFACE HFEC
INSPECTION
INTERNAL ULTRASONIC  BACKING BOARD
INSPECTION  ATTACH ANGLE
2 REAR SPAR  • LOWER CHORD
• REAR SPAR PLANE
• REAR SPAR WEB
• REAR SPAR WEB  1) LOWER SKIN
STIFFENER
- (2.00 MIN)
WD
(VIEW ROTATED 90 DEGREES CCW)
(FASTENER HEAD ORIENTATION MAY
NOT BE EXACTLY AS SHOWN)
C-C
STIFFENER SUPPORT
BRACKET
REAR SPAR LOWER
CHORD
1) LOWER SKIN
-(2.00 MIN)
(VIEW LOOKING INBOARD ROTATED 90 DEGREES CCW)
(STIFFENER SUPPORT BRACKET ORIENTATION
AND SHAPE MAY NOT BE EXACTLY AS SHOWN)  2972282
D-D
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION
(SHEET 4 OF 5)
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### 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-LOWER SKINInspect1
(b)1-REAR SPAR LOWER
CHORD
Inspect2
(c)1-REAR SPAR LOWER
CHORD
Inspect3
(a) Do an internal Detailed Inspection of the lower skin for any crack.
(b) Do an internal surface High Frequency Eddy Current Inspection around all fastener heads or collars
within 0.10 inch on all fasteners not covered by a stiffener support brackets on the rear spar lower chord
horizontal surface for any crack in accordance with 707, 720 NDT Manual Part 6, 57-10-07, Figure 13
Detail VI.
(c) Do an internal Ultrasonic Inspection of the rear spar lower chord for any crack in accordance with 707,
720 NDT Manual Part 4, 57-10-07, Figure 1.
FIGURE 2: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - INSPECTION
(SHEET 5 OF 5)
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A3544 RB
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REQUIREMENTS BULLETIN A3544
ALERTALERT

### Page 24 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
AFT FUEL CELL
STA
820
REAR
SPAR
RBBL  LBBL
REAR SPAR  34.00  34.00  REAR SPAR
WEB  RBBL  RBBL  RBBL  LBBL  LoBL  LBBL  LOWER CHORD
40.00  24.85  12.88  12.88  24.85  40.00
VAPOR BARRIER SEAL  LOWER SKIN
WING CENTER SECTION REAR SPAR
(VIEW LOOKING AFT)
(STIFFENER LAYOUT, STIFFENER SUPPORT BRACKET ORIENTATION
AND BUTTOCK STATIONS MAY NOT BE EXACTLY AS SHOWN)  2971953
A-A
FIGURE 3: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - SEALANT APPLICATION
(SHEET 1 OF 4)
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### Page 25 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
LBBL
40.00
STIFFENER  REAR SPAR  REF
BBL  0.00  SEALANT  LBBL  12.88  SUPPORT  BRACKET  - C  LOWER CHORD  LBBL  42.20
REAR
SPAR
PLANE
LOWER  SKIN  SEALANT  - C  FROM EDGE OF  0.10 MAXIMUM  STIFFENER  STIFFENER  SUPPORT
RBBL
40.00  RBBL
REF  12.88
REAR SPAR
RBBL  LOWER CHORD  788
42.20  0.00
REAR
SPAR
PLANE
0.10 MAXIMUM
FROM EDGE OF  NIXS
STIFFENER  STIFFENER
SUPPORT  SUPPORT
BRACKET  BRACKET
REAR SPAR LOWER CHORD AND LOWER SKIN
(VIEW LOOKING DOWN)
(STIFFENER SUPPORT BRACKET ORIENTATION, BUTTOCK STATIONS
AND FASTENER LOCATIONS MAY NOT BE EXACTLY AS SHOWN)
B-B  2972290
FIGURE 3: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - SEALANT APPLICATION
(SHEET 2 OF 4)
Original Issue: November 01, 2021
Export Controlled ECCN: 9E991  A3544 RB
Copyright © Unpublished
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### Page 26 (OCR)

REQUIREMENTS BULLETIN A3544
ALERT  ALERT
• REAR SPAR
PLANE
REAR SPAR
WEB
LOWER CHORD~  REAR SPAR  BACKING BOARD  ATTACH ANGLE
SEALANT
0.10
MINIMUM
/ PLANE  REAR SPAR  0.12  MINIMUM  0.12  0.10  MINIMUM
REAR SPAR
WEB  1 SEALANT
• REAR SPAR
WEB  0.10
STIFFENER  LOWER  SKIN  MINIMUM  0.08  MINIMUM  -0.15  MINIMUM  0.15  MINIMUM
(VIEW ROTATED 90 DEGREES CCW
(FASTENER HEAD ORIENTATION MAY
STIFFENER  NOT BE EXACTLY AS SHOWN)
BRACKET  SUPPORT  C-C
SEALANT
(FORWARD, INBOARD AND
OUTBOARD EDGES ONLY)
0.15
MINIMUM  0.08  1) SEALANT
MINIMUM
(0.08
MINIMUM)  MINIMUM)  (0.15
0.15
MINIMUM-
REAR SPAR  LOWER CHORD  • (0.15  MINIMUM)  LOWER
SKIN
(VIEW LOOKING INBOARD ROTATED 90 DEGREES CCW)
STIFFENER SUPPORT BRACKET ORIENTATION  -WD
AND SHAPE MAY NOT BE EXACTLY AS SHOWN)  2972291
D-D
FIGURE 3: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - SEALANT APPLICATION
(SHEET 3 OF 4)
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Export Controlled ECCN: 9E991  A3544 RB
Copyright © Unpublished
Work - See page 1 for details.  26 of 27

### Page 27

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)-BMS 5-45SEALANTApply1
(b)-BMS 5-45SEALANTApply2
(a) Apply fillet sealant to lower skin and rear spar lower chord inspection area. Refer to SOPM 20-50-19 as
an accepted procedure.
(b) In areas where the sealant was removed, apply sealant. It is acceptable to apply sealant where it was
not applied before. Refer to SOPM 20-50-19 as an accepted procedure.
FIGURE 3: CENTER WING BOX, LOWER SKIN AND REAR SPAR LOWER CHORD - SEALANT APPLICATION
(SHEET 4 OF 4)
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A3544 RB
27 of 27
REQUIREMENTS BULLETIN A3544
ALERTALERT

---
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