[Federal Register Volume 89, Number 195 (Tuesday, October 8, 2024)]
[Rules and Regulations]
[Pages 81314-81320]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-23117]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0769; Project Identifier AD-2023-00556-T; 
Amendment 39-22815; AD 2024-16-09]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain The Boeing Company Model 777-200, -200LR, -300, -300ER, and 
777F series airplanes. This AD was prompted by a report indicating 
multiple findings of cracks in the fuselage skin common to the 
underwing longeron (UWL). This AD requires external or internal 
(depending on configuration) inspections for any cracking of the left 
and right side fuselage skin common to the UWL, and applicable on-
condition actions. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective November 12, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of November 12, 
2024.

ADDRESSES: 

[[Page 81315]]

    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-0769; or in person at Docket Operations between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains this final rule, any comments received, and other 
information. The address for Docket Operations is U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
    <bullet> For Boeing material identified in this AD, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110 SK57, Seal Beach, CA 90740-5600; 
telephone 562 797 1717; website myboeingfleet.com.
    <bullet> You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., Des 
Moines, WA. For information on the availability of this material at the 
FAA, call 206-231-3195. It is also available at regulations.gov under 
Docket No. FAA-2024-0769.

FOR FURTHER INFORMATION CONTACT: Luis Cortez-Muniz, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3958; email: <a href="/cdn-cgi/l/email-protection#6509100c164b044b060a1711001f4808100b0c1f250304044b020a13"><span class="__cf_email__" data-cfemail="7d1108140e531c531e120f0918075010081314073d1b1c1c531a120b">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain The Boeing 
Company Model 777-200, -200LR, -300, -300ER, and 777F series airplanes. 
The NPRM published in the Federal Register on March 28, 2024 (89 FR 
21446). The NPRM was prompted by a report indicating multiple findings 
of cracks in the fuselage skin common to the UWL. In the NPRM, the FAA 
proposed to require external or internal (depending on configuration) 
inspections for any cracking of the left and right side fuselage skin 
common to the UWL, and applicable on-condition actions. The FAA is 
issuing this AD to address fuselage skin cracking caused by cold work 
surface upset that is not removed from the mating parts and high joint 
load transfer or significant local bending stresses at critical 
fastener locations. The unsafe condition, if not addressed, could 
result in an inability of a principal structural element (PSE) to 
sustain limit load, leading to reduced structural integrity of the 
airplane and possible loss of control of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from FedEx Express, who found no issues 
that could interfere with the timely implementation of the proposed 
actions in the NPRM.
    The FAA received additional comments from three commenters, 
including American Airlines, Boeing, and United Airlines. The following 
presents the comments received on the NPRM and the FAA's response to 
each comment.

Request To Clarify Locations Specified in Paragraph (h)(3) of the 
Proposed AD

    Boeing requested that paragraph (h)(3) of the proposed AD be 
clarified to specify that only the fuel tank side of fastener locations 
that penetrate the fuel tank boundary require cap seal dimensions to 
meet the dimensions given in Figure 1 to paragraph (h)(3) of the 
proposed AD. Boeing stated that the service information referenced in 
Boeing Alert Requirements Bulletin 777-53A0100 RB, dated March 16, 
2023, contain instructions for applying cap seals to fasteners that 
penetrate a fuel tank boundary and fasteners that do not penetrate a 
fuel tank boundary. Boeing added that for fasteners that do not 
penetrate a fuel tank boundary, fastener sealing is used as a pressure 
seal to help mitigate corrosion and have sealing specifications that 
include minimum thickness requirements less than the amount shown in 
paragraph (h)(3) of the proposed AD that are acceptable for their 
intended function outside of the fuel tank. Boeing stated that for 
fasteners that penetrate the fuel tank, the cap seals on the interior 
side of the fuel tank act as a primary fuel seal, providing fault 
tolerance against electromagnetic effects (electrical fault currents 
and lightning currents), and are also cap sealed on the exterior side 
for corrosion prevention.
    Boeing concluded that only the cap seals on the interior side of 
the fuel tank require the dimensions specified in Figure 1 of paragraph 
(h)(3) of the proposed AD to perform their intended function, which is 
consistent with the labels shown in Figure 1 of paragraph (h)(3) of the 
proposed AD. Boeing recommended replacing the text ``applying a cap 
seal (sealant) to a fastener, fastener head, and fastener threads and 
collars, for this AD, during application of any cap seal to a fastener, 
fastener head, or fastener threads and collars'' with the text 
``applying a cap seal (sealant) to a fastener location that penetrates 
the fuel tank boundary, for this AD, during application of any cap seal 
to a fastener, fastener head, or fastener threads and collars inside 
the fuel tank.''
    The FAA agrees to clarify paragraph (h)(3) of this AD for the 
reasons provided by the commenter. Locations that do not penetrate the 
fuel tank boundary do not require the same sealant application 
procedures. The FAA has added the text ``inside the fuel tank'' to 
paragraph (h)(3) of this AD. However, the FAA did not replace the text 
``to a fastener, fastener head, and fastener threads and collars'' with 
the text ``to a fastener location that penetrates the fuel tank 
boundary,'' as recommended by the commenter, because the text ``to a 
fastener, fastener head, and fastener threads and collars inside the 
fuel tank'' better aligns with the language within the service 
information.

Request To Clarify Service Information in Paragraph (h)(3) of the 
Proposed AD

    American Airlines requested that the FAA provided a comprehensive 
list of all service information that will be impacted by paragraph 
(h)(3) of the proposed AD. American Airlines stated that the statement 
``Where any service information referenced in Boeing Alert Requirements 
Bulletin 777-53A0100 RB'' is vague and could potentially lead to 
confusion.
    The FAA agrees to specify the service information affected by 
paragraph (h)(3) of this AD. In addition, the FAA notes that paragraph 
(h)(2) of this AD has similar language (``Where . . . any service 
information referenced in Boeing Alert Requirements Bulletin 777-
53A0100 RB''). The FAA has added a note to paragraphs (h)(2) and (3) of 
this AD to specify that Boeing Alert Requirements Bulletin 777-53A0100 
RB, dated March 16, 2023, refers to Boeing Service Bulletin 777-53-
0084, Revision 2, dated December 9, 2020; Boeing Service Bulletin 777-
53-0087, Revision 1, dated March 4, 2020; and Boeing Alert Requirements 
Bulletin 777-57A0122 RB, dated October 8, 2021.

Request To Add a Note to Paragraph (h)(3) of the Proposed AD

    Boeing requested that the FAA add a note to paragraph (h)(3) of the 
proposed AD to refer to Boeing Model 777 Aircraft Maintenance Manual 
(AMM) section 28-11-00 as an acceptable cap sealing procedure to 
accomplish the actions required in that paragraph. Boeing stated it has 
received numerous queries from operators on Figure 1 to paragraph 
(h)(4) of AD 2023-17-14, which is identical to Figure 1 to paragraph 
(h)(3)

[[Page 81316]]

of the proposed AD. Operators have asked whether Boeing Model 777 AMM 
section 28-11-00 would be an acceptable procedure for accomplishing the 
requirements of paragraph (h)(4) of AD 2023-17-14. Boeing stated it 
believes that AMM 28-11-00 is an acceptable procedure for performing 
cap sealing inside the fuel tank because the AMM is the source material 
for the contents in Figure 1 to paragraph (h)(3) of the proposed AD and 
contains the same minimum seal thickness dimensions as shown in Figure 
1.
    The FAA agrees. Boeing 777 AMM 28-11-00 meets the sealant 
requirements of Figure 1 to paragraph (h)(3) of this AD. As such, it 
would be an acceptable procedure to follow when sealing inside the fuel 
tank in accordance with paragraph (h)(3) of this AD. The FAA has added 
a note to paragraph (h)(3) of this AD accordingly.

Request for Removal of Certain Exceptions That Are Related to Other ADs

    United Airlines (United) requested removal of the exceptions in 
paragraphs (h)(4) through (6) of the proposed AD that are for service 
information other than Boeing Alert Requirements Bulletin 777-53A0100 
RB, dated March 16, 2023. United stated that it agrees with the 
intention of the proposed AD, but found the exceptions stated in 
paragraphs (h)(4) through (6) of the proposed AD to be unclear. United 
stated that it has other ongoing projects that use the instructions of 
Boeing Service Bulletin 777-53-0084, Revision 2, dated December 9, 
2020; Boeing Service Bulletin 777 53-0087, Revision 1, dated March 4, 
2020; and Boeing Alert Requirements Bulletin 777-57A0122 RB, dated 
October 8, 2021; to comply with the requirements of AD 2019-11-02, 
Amendment 39-19648 (84 FR 28722, June 20, 2019) (AD 2019-11-02) and AD 
2023-17-14, Amendment 39-22541 (88 FR 60111, August 31, 2023) (AD 2023-
17-14). United pointed out that ADs 2019-11-02 and 2023-17-14 have not 
been updated to include the exceptions in those AD requirements and 
recommends that the exceptions removed from paragraphs (h)(4) through 
(6) of the proposed AD be added to the requirements of ADs 2019-11-02 
and 2023-17-14.
    The FAA disagrees with the request to remove the exceptions in 
paragraphs (h)(4) through (6) of this AD. If cracking is found during 
certain inspections required by Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023, then certain actions in Boeing 
Service Bulletin 777-53-0084, Revision 2, dated December 9, 2020; 
Boeing Service Bulletin 777-53-0087, Revision 1, dated March 4, 2020; 
or Boeing Alert Requirements Bulletin 777-57A0122 RB, dated October 8, 
2021; might be required as corrective actions. In order to address the 
identified unsafe condition, the service information, as applicable, 
must be accomplished with the exceptions specified in (h)(4) through 
(6) of this AD. There are no new requirements for AD 2019-11-02 and AD 
2023-17-14. However, as stated in paragraph (i) of this AD, for 
airplanes on which a front spar lower chord modification specified in 
Boeing Alert Requirements Bulletin 777-57A0122 RB is done as part of 
the requirements of paragraphs (g) and (h)(6) of this AD, the 
modification requirements of paragraph (g) of AD 2023-17-14 are 
terminated for the applicable side (left or right) on which the 
modification was done.
    In addition, in the ``Approval'' paragraphs of Boeing Service 
Bulletin 777-53-0084, Revision 2, dated December 9, 2020; Boeing 
Service Bulletin 777-53-0087, Revision 1, dated March 4, 2020; and 
Boeing Alert Requirements Bulletin 777-57A0122 RB, dated October 8, 
2021; it specifies that certain actions are an alternative method of 
compliance (AMOC) to the inspection and corrective action requirements 
of paragraph (g) of AD 2019-11-02, for modified longerons only. The FAA 
has not changed this AD in this regard.

Request To Add Paragraph for Terminating Action for AD 2019-11-02

    American Airlines requested that the FAA add a paragraph similar to 
paragraph (i) of the proposed AD for terminating action for AD 2023-17-
14 that refers to Boeing Service Bulletin 777-53-0087, Revision 1, 
dated March 4, 2020, as the terminating action to AD 2019-11-02.
    The FAA does not agree. As previously stated, the ``Approval'' 
paragraph of Boeing Service Bulletin 777-53-0087, Revision 1, dated 
March 4, 2020, already includes an approval paragraph for the 
requirements of AD 2019-11-02. The FAA has not revised this AD in this 
regard.

Request To Add Clarifying Paragraph for Repetitive Inspections

    American Airlines requested that the FAA add a paragraph clarifying 
that ``If SB 777-53-0087 Rev 1 is accomplished due to findings from the 
inspections described in SB 777-53A0081 R02 (AD 2019-11-02), and NO 
skin repair is done, the repetitive inspections IAW SB 777-53A0100 will 
still be required since terminating action for those inspections is 
only valid if the underwing longeron AND fuselage skin modification is 
accomplish in accordance with SB 777-53-0087 R01.''
    The FAA concurs with American Airlines' statement that repetitive 
inspections continue until the fuselage skin modification is done. The 
UWL with fuselage skin modification is terminating action to the repeat 
inspections in Boeing Alert Requirements Bulletin 777-53A0100 RB, dated 
March 16, 2023. If Boeing Service Bulletin 777-53-0087, Revision 1, 
dated March 4, 2020, is accomplished without the fuselage skin 
modification, repeat inspections in accordance with Boeing Alert 
Requirements Bulletin 777-53A0100 RB, dated March 16, 2023, continue to 
apply. The FAA notes that flagnote (a) in the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023, specifies ``Accomplishment of the 
left side UWL with fuselage skin modification in accordance with 
Revision 1 of Boeing Service Bulletin 777-53-0087 is terminating action 
for this repeat inspection.''
    The FAA also notes where in the second paragraph of ``Other 
Relevant Rulemaking'' of the NPRM states ``The accomplishment of the 
longeron modification specified in Boeing Service Bulletin 777-53-0084, 
Revision 2, dated December 9, 2020, or Boeing Service Bulletin 777-53-
0087, Revision 1, dated March 4, 2020'' the text should state ``The 
accomplishment of the longeron modification with fuselage skin 
modification specified in Boeing Service Bulletin 777-53-0084, Revision 
2, dated December 9, 2020, or Boeing Service Bulletin 777-53-0087, 
Revision 1, dated March 4, 2020.'' However, the ``Other Relevant 
Rulemaking'' paragraphs are not restated in this AD. The FAA has not 
revised this AD in this regard.

Request To Allow Later Revisions of Service Information

    American Airlines requested that the FAA allow the use of future 
revisions of Boeing Service Bulletin 777-53-0087, Revision 1, dated 
March 4, 2020. American Airlines stated the Revision 2 of Boeing 
Service Bulletin 777-53-0087 will add new replacement and supplemental 
kits, add fastener installation instructions, update bracket 
installation instructions, correct fastener callouts and correct 
typographical errors.
    The FAA does not agree. Revision 2 of Boeing Service Bulletin 777-
53-0087 has not yet been FAA approved nor been published. The FAA may 
not refer to any document that does not yet exist in an AD. To allow 
operators to use later

[[Page 81317]]

revisions of the referenced document (issued after publication of the 
AD), either the FAA must revise the AD to reference specific later 
revisions, or operators must request approval to use later revisions as 
an alternative method of compliance with this AD under the provisions 
of paragraph (j) of this AD.

Request To Clarify Paragraph (h)(5) of the Proposed AD

    American Airlines requested that the FAA clarify if paragraph 
(h)(5) of the proposed AD is exclusive to the center wing fuel tank 
location, or whether adjustments should also be made to the other steps 
that offer the choice to utilize Boeing Material Specification (BMS) 5-
95 sealant or other sealants.
    The FAA agrees to clarify. The exception in paragraph (h)(5) of 
this AD is applicable to sealant application in the center wing fuel 
tank only. The use of BMS 5-95 sealant instead of BMS 5-45 sealant is 
only a concern when the location being sealed is inside a fuel tank 
such that the sealant is directly exposed to fuel. Only Figure 13 and 
Figure 49 describe sealing operations inside a fuel tank using BMS 5-95 
sealant. As such, paragraph (h)(5) of this AD is specifically limited 
to flagnote (f) of Figure 13 and Figure 49. Other locations (i.e., 
other flagnotes and figures) in the service information that provide an 
option of BMS 5-45 and BMS 5-95 are acceptable as written. The FAA also 
notes that a similar rationale applies to the exception in paragraph 
(h)(4) of this AD. The FAA has not changed this AD in this regard.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 777-53A0100 RB, 
dated March 16, 2023. This material specifies procedures for external 
or internal (depending on configuration) detailed and ultrasonic or 
surface high frequency eddy current (HFEC) inspections for any cracking 
of the left and right side fuselage skin common to the UWL, and 
applicable on-condition actions. On-condition actions include, among 
other things, modification of the fuselage skin, and post-modification 
inspections and applicable corrective actions (repairs of cracking). 
Compliance times for on-condition actions depend on inspection type, 
inspection findings, and modification status.
    The FAA also reviewed Boeing Multi Operator Message MOM-MOM-24-
0054-01B, dated January 26, 2024. This material specifies corrections 
for Boeing Alert Requirements Bulletin 777-57A0122 RB, dated October 8, 
2021, that address a non-destructive test manual (NDTM) error, fastener 
callout errors, inadequate cap seal instructions, figure orientation 
errors, minimum gap errors, missing fasteners on certain figures, 
affected groups missing from certain figures, and typographical errors.
    This material is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 272 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                    Labor cost         Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
External or internal inspections  Up to 21 work-hours              $0   $1,785 per           $485,520 per
                                   x $85 per hour =                      inspection cycle.    inspection cycle.
                                   $1,785 per
                                   inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of the 
inspection. The agency has no way of determining the number of aircraft 
that might need these actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                 Action                           Labor cost            Parts cost         Cost per product
----------------------------------------------------------------------------------------------------------------
Modification............................  420 work-hours x $85 per           $40,620  $76,320.
                                           hour = $35,700.
Post-modification inspections...........  46 work-hours x $85 per                  0  $3,910 per inspection
                                           hour = $3,910 per                           cycle.
                                           inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs specified in this AD.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this AD may be covered under warranty, thereby reducing the cost impact 
on affected operators.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

[[Page 81318]]

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2024-16-09 The Boeing Company: Amendment 39-22815; Docket No. FAA-
2024-0769; Project Identifier AD-2023-00556-T.

(a) Effective Date

    This airworthiness directive (AD) is effective November 12, 
2024.

(b) Affected ADs

    This AD affects AD 2023-17-14, Amendment 39-22541 (88 FR 60111, 
August 31, 2023) (AD 2023-17-14).

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F series airplanes, certificated in any 
category, as identified in Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by a report indicating multiple findings of 
cracks in the fuselage skin common to the underwing longeron (UWL). 
The FAA is issuing this AD to address fuselage skin cracking caused 
by cold work surface upset that is not removed from the mating parts 
and high joint load transfer or significant local bending stresses 
at critical fastener locations. The unsafe condition, if not 
addressed, could result in an inability of a principal structural 
element (PSE) to sustain limit load, leading to reduced structural 
integrity of the airplane and possible loss of control of the 
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 777-53A0100 RB, dated March 16, 2023, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
777-53A0100 RB, dated March 16, 2023.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
777-53A0100, dated March 16, 2023, which is referred to in Boeing 
Alert Requirements Bulletin 777-53A0100 RB, dated March 16, 2023.
    Note 2 to paragraph (g): Guidance for accomplishing certain on-
condition actions required by paragraph (g) of this AD can be found 
in Boeing Service Bulletin 777-53-0084, Revision 2, dated December 
9, 2020; Boeing Service Bulletin 777-53-0087 Revision 1, dated March 
4, 2020; and Boeing Alert Requirements Bulletin 777-57A0122 RB, 
dated October 8, 2021.

(h) Exceptions to Requirements Bulletin Specifications

    (1) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023, use the phrase ``the original 
issue date of Requirements Bulletin 777-53A0100 RB,'' this AD 
requires using the effective date of this AD.
    (2) Where Boeing Alert Requirements Bulletin 777-53A0100 RB, 
dated March 16, 2023, and any service information referenced in 
Boeing Alert Requirements Bulletin 777-53A0100 RB, dated March 16, 
2023, specifies contacting Boeing for repair instructions: This AD 
requires doing the repair using a method approved in accordance with 
the procedures specified in paragraph (j) of this AD.
    Note 3 to paragraph (h)(2): This note applies to paragraphs 
(h)(2) and (3) of this AD. Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023, refers to Boeing Service Bulletin 
777-53-0084, Revision 2, dated December 9, 2020; Boeing Service 
Bulletin 777-53-0087, Revision 1, dated March 4, 2020; and Boeing 
Alert Requirements Bulletin 777-57A0122 RB, dated October 8, 2021.
    (3) Where any service information referenced in Boeing Alert 
Requirements Bulletin 777-53A0100 RB, dated March 16, 2023, 
specifies applying a cap seal (sealant) to a fastener, fastener 
head, and fastener threads and collars inside the fuel tank, for 
this AD, during application of any cap seal to a fastener, fastener 
head, or fastener threads and collars inside the fuel tank, the cap 
seal must be applied using a cap sealing procedure with thickness 
greater than or equal to the dimensions given in Figure 1 to 
paragraph (h)(3) of this AD.
    Note 4 to paragraph (h)(3): Guidance on an acceptable cap 
sealing procedure for accomplishing the actions required by 
paragraph (h)(3) of this AD can be found in Boeing Model 777 
Aircraft Maintenance Manual (AMM) section 28-11-00.

Figure 1 to Paragraph (h)(3)--Cap Sealing Dimensions (all Dimensions 
are in Inches)

[[Page 81319]]

[GRAPHIC] [TIFF OMITTED] TR08OC24.009

    (4) Where Boeing Alert Requirements Bulletin 777-53A0100 RB, 
dated March 16, 2023, specifies doing actions ``in accordance with 
Revision 2 of Boeing Service Bulletin 777-53-0084,'' for this AD, 
where flagnote (f) of Figure 7 and Figure 22 of that referenced 
service information (``Revision 2 of Boeing Service Bulletin 777-53-
0084'') includes a sealant callout of Boeing Material Specification 
(BMS) 5-45 or an optional BMS 5-95, only BMS 5-45 is allowed.
    (5) Where Boeing Alert Requirements Bulletin 777-53A0100 RB, 
dated March 16, 2023, specifies doing actions ``in accordance with 
Revision 1 of Boeing Service Bulletin 777-53-0087,'' for this AD, 
where flagnote (f) of Figure 13 and Figure 49 of that referenced 
service information (``Revision 1 of Boeing Service Bulletin 777-53-
0087'') includes a sealant callout of BMS 5-45 or an optional BMS 5-
95, only BMS 5-45 is allowed.
    (6) Where Boeing Alert Requirements Bulletin 777-53A0100 RB, 
dated March 16, 2023, specifies doing actions ``in accordance with 
the original issue of Boeing Alert Requirements Bulletin 777-57A0122 
RB,'' for this AD, the exceptions specified in paragraph (h)(6)(i) 
through (v) of this AD apply to that referenced service information 
(``the original issue of Boeing Alert Requirements Bulletin 777-
57A0122 RB'') and the corrections identified in Boeing Multi 
Operator Message MOM-MOM-24-0054-01B, dated January 26, 2024, apply 
to that referenced service information.
    (i) Where the ``Compliance'' paragraph of the referenced service 
information identifies ``Tables 1 through 50,'' the correct number 
of tables is Tables 1 through 54.
    (ii) The referenced service information does not specify the 
application of cap seals to underwing longeron fasteners, fastener 
heads, and fastener threads and collars for the airplane groups and 
configurations identified in paragraphs (h)(6)(ii)(A) through (D) of 
this AD. For those airplane groups and configurations, the 
application of a cap seal to the underwing longeron fasteners at the 
locations identified in Figures 81 and 144 is required during 
installation of the underwing longeron and must be applied using a 
cap sealing procedure with thickness greater than or equal to the 
dimensions given in Figure 1 to paragraph (h)(3) of this AD.
    (A) Groups 7 and 8, Configurations 5 through 8, on the left 
side.
    (B) Group 9, Configurations 1 and 2, on the left side.
    (C) Groups 7 and 8, Configurations 2, 6, 10, and 14, on the 
right side.
    (D) Group 9, Configurations 1 and 3, on the right side.
    (iii) For any inspection that may require the removal of 
fastener cap seals, if the cap seal is removed, a cap seal of BMS 5-
45 sealant must be reapplied using a cap sealing procedure with a 
thickness equal to or greater than the dimensions specified in 
Figure 1 to paragraph (h)(3) of this AD before further flight after 
completion of the inspection.
    (iv) The referenced service information does not require the 
restoration of any sealant removed to accomplish high frequency eddy 
current and ultrasonic inspections external to the fuel tank in 
Figures 1, 7, 11, and 17. Following completion of any inspection 
required by those figures, replacement of the sealant described in 
paragraph (h)(6)(iv)(A) and repair of the sealant described in 
paragraph (h)(6)(iv)(B) of this AD, as applicable, is required.
    (A) Where any sealant was removed from the heads of fasteners, 
before further flight, cover and fillet seal the fasteners using BMS 
5-45 or BMS 5-95 sealant.
    Note 5 to paragraph (h)(6)(iv)(A): Guidance for accomplishing 
the actions required by paragraph (h)(6)(iv)(A) of this AD can be 
found in the Boeing Standard Overhaul Practices Manual (SOPM) 
section 20-50-19.
    (B) Following any sealant replacement required by paragraph 
(h)(6)(iv)(A) of this AD, where any secondary fuel barrier coating 
was removed, before further flight, repair the secondary fuel 
barrier using BMS 5-81 sealant.
    Note 6 to paragraph (h)(6)(iv)(B): Guidance for accomplishing 
the actions required by paragraph (h)(6)(iv)(B) of this AD can be 
found in Boeing Model 777 Aircraft Maintenance Manual (AMM) section 
28-11-00.
    (v) The Effectivity of the referenced service information does 
not include Boeing Model 777F series airplanes having line numbers 
1713, 1717, 1720, and 1724 through 1742 inclusive. For those 
airplanes the applicable actions for Group 6 must be done.

(i) Terminating Action for AD 2023-17-14

    For airplanes on which a front spar lower chord modification 
specified in Boeing Alert Requirements Bulletin 777-57A0122 RB is 
done as part of the requirements of paragraphs (g) and (h)(6) of 
this AD, the modification requirements of paragraph (g) of AD 2023-
17-14 are terminated for the applicable side (left or right) on 
which the modification was done.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520, Continued Operational Safety Branch, 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or 
responsible Flight Standards Office, as appropriate. If sending 
information directly to the manager of the Continued Operational 
Safety Branch, send it to the attention of the person identified in 
paragraph (k)(1) of this AD. Information may be emailed to: 
<a href="/cdn-cgi/l/email-protection#56171b19151630373778313920"><span class="__cf_email__" data-cfemail="d1909c9e9291b7b0b0ffb6bea7">[email protected]</span></a>.

[[Page 81320]]

    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, AIR-
520, Continued Operational Safety Branch, FAA, to make those 
findings. To be approved, the repair method, modification deviation, 
or alteration deviation must meet the certification basis of the 
airplane, and the approval must specifically refer to this AD.

(k) Related Information

    (1) For more information about this AD, contact Luis Cortez-
Muniz, Aviation Safety Engineer, FAA, 2200 South 216th St., Des 
Moines, WA 98198; phone: 206-231-3958; email: <a href="/cdn-cgi/l/email-protection#96fae3ffe5b8f7b8f5f9e4e2f3ecbbfbe3f8ffecd6f0f7f7b8f1f9e0"><span class="__cf_email__" data-cfemail="7d1108140e531c531e120f0918075010081314073d1b1c1c531a120b">[email protected]</span></a>.
    (2) Material identified in this AD that is not incorporated by 
reference is available at the address specified in paragraph (l)(3) 
of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the material listed in this 
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 777-53A0100 RB, dated 
March 16, 2023.
    (ii) Boeing Multi Operator Message MOM-MOM-24-0054-01B, dated 
January 26, 2024.
    (3) For Boeing material, contact Boeing Commercial Airplanes, 
Attention: Contractual & Data Services (C&DS), 2600 Westminster 
Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-
1717; website myboeingfleet.com.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., 
Des Moines, WA. For information on the availability of this material 
at the FAA, call 206-231-3195.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email <a href="/cdn-cgi/l/email-protection#94f2e6bafdfae7e4f1f7e0fdfbfad4faf5e6f5baf3fbe2"><span class="__cf_email__" data-cfemail="96f0e4b8fff8e5e6f3f5e2fff9f8d6f8f7e4f7b8f1f9e0">[email protected]</span></a>.

    Issued on August 1, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-23117 Filed 10-7-24; 8:45 am]
BILLING CODE 4910-13-P


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