Rule2023-18835
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 31, 2023
Effective
September 15, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is superseding Airworthiness Directive (AD) 2022-18- 11, which applied to all The Boeing Company Model 777 airplanes. AD 2022-18-11 required repetitive inspections for cracking of the left- and right-side ring chords, repair angles, front spar lower chords, and front spar webs (depending on configuration) common to a certain underwing longeron; modification of the front spar lower chord for some airplanes; repetitive post-modification inspections; and applicable on- condition actions. This AD was prompted by a report of a crack found in a front spar lower chord, and the determination that errors in the service information mandated by AD 2022-18-11 introduced a new unsafe condition related to the application of certain fastener cap seals. This AD retains the actions required by AD 2022-18-11, and requires a maintenance records review of previously modified airplanes for the procedures used during that modification, and applicable corrective actions. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 88 Issue 168 (Thursday, August 31, 2023)</title>
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[Federal Register Volume 88, Number 168 (Thursday, August 31, 2023)]
[Rules and Regulations]
[Pages 60111-60116]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-18835]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-1814; Project Identifier AD-2023-00773-T;
Amendment 39-22541; AD 2023-17-14]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2022-18-
11, which applied to all The Boeing Company Model 777 airplanes. AD
2022-18-11 required repetitive inspections for cracking of the left-
and right-side ring chords, repair angles, front spar lower chords, and
front spar webs (depending on configuration) common to a certain
underwing longeron; modification of the front spar lower chord for some
airplanes; repetitive post-modification inspections; and applicable on-
condition actions. This AD was prompted by a report of a crack found in
a front spar lower chord, and the determination that errors in the
service information mandated by AD 2022-18-11 introduced a new unsafe
condition related to the application of
[[Page 60112]]
certain fastener cap seals. This AD retains the actions required by AD
2022-18-11, and requires a maintenance records review of previously
modified airplanes for the procedures used during that modification,
and applicable corrective actions. The FAA is issuing this AD to
address the unsafe condition on these products.
DATES: This AD is effective September 15, 2023.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 31,
2022 (87 FR 58259, September 26, 2022).
The FAA must receive comments on this AD by October 16, 2023.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
<bullet> Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> by
searching for and locating Docket No. FAA-2023-1814; 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 street address for Docket
Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Kevin Nguyen, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3555; email: <a href="/cdn-cgi/l/email-protection#c48fa1b2adaaea8aa3b1bda1aa84a2a5a5eaa3abb2"><span class="__cf_email__" data-cfemail="aae1cfdcc3c484e4cddfd3cfc4eacccbcb84cdc5dc">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued AD 2022-18-11, Amendment 39-22162 (87 FR 58259,
September 26, 2022) (AD 2022-18-11), for all The Boeing Company Model
777 airplanes. AD 2022-18-11 required repetitive inspections for
cracking of the left- and right-side ring chords, repair angles, front
spar lower chords, and front spar webs (depending on configuration)
common to the underwing longeron located at station (STA) 1035;
modification of the front spar lower chord for some airplanes;
repetitive post-modification inspections; and applicable on-condition
actions. AD 2022-18-11 was prompted by a report of a crack found in the
front spar lower chord of a Model 777-300ER airplane undergoing an
underwing longeron replacement. The FAA issued AD 2022-18-11 to
address, detect, and correct such cracking, which in combination with
cracking in the front spar web, could result in a fuel leak and fire
hazard, or in the case of more severe cracking, could also affect the
structural integrity of the airplane.
Actions Since AD 2022-18-11 Was Issued
Since the FAA issued AD 2022-18-11, the manufacturer has discovered
that Boeing Alert Requirements Bulletin 777-57A0122 RB, dated October
8, 2021, which was mandated by AD 2022-18-11, contains errors relating
to the application of cap seals to fasteners penetrating the center
wing fuel tank which introduce a second, urgent unsafe condition. These
errors necessitate superseding AD 2022-18-11 to add additional actions
to correct this new unsafe condition.
Fastener cap seals interior to the airplane's fuel tanks are a
critical lightning protection feature. This is particularly true for
the center wing fuel tank, which typically contains flammable fuel
vapors more frequently than the main wing fuel tanks. As part of the
front spar lower chord and underwing longeron work described in the
manufacturer's requirements bulletin and mandated by AD 2022-18-11,
many cap seals are removed to accomplish the various modifications and
inspections. If these seals are not replaced properly, and the
associated fastener has poor electrical bonding to the airplane
structure for any reason, the fastener may spark during a lightning
strike and cause a fuel tank explosion.
The lack of fault-tolerance introduced by these cap sealing errors
in the manufacturer's requirements bulletin places an airplane with
compromised cap seals that has no flammability reduction or ignition
mitigation means at a level of risk that requires urgent action to
address. Airplanes equipped with flammability reduction or ignition
mitigation means are also affected by this newly created unsafe
condition, but at a lower level of risk. Paragraph (e) of this AD,
Unsafe Condition, has been revised to reflect the second unsafe
condition created by the errors in the manufacturer's requirements
bulletin as described above. Paragraph (e) of this AD has also been
revised to reflect the determination that existing structural
inspections are expected to detect severe front spar lower chord
cracking before the structural integrity of the airplane is put at
risk, but are not expected to detect cracking before a possible fuel
leak. The unsafe condition therefore now consists of two distinct
aspects: structural cracking of the front spar lower chord leading to a
fuel leak and possible fire, and failure of fastener cap seals to
contain a possible spark following a lightning strike leading to a
possible fuel tank explosion.
The manufacturer submitted an initial report of errors in the
requirements bulletin affecting cap sealing instructions in late 2022.
However, given the length and complexity of the requirements bulletin,
detailed and complete documentation of these errors was not received
until late July 2023. The manufacturer has stated its intent to revise
the requirements bulletin; however, this work will take longer to
accomplish than the risk to public safety allows. Therefore, the FAA
has proceeded with this supersedure without additional service
information as soon as possible following the manufacturer's delivery
of the necessary information. The three categories of errors affecting
cap sealing instructions in the manufacturer's requirements bulletin
are described as follows.
First, certain groups and configurations of airplanes have no
requirement to apply cap seals to fasteners associated with the
underwing longeron. Without this requirement, a cap seal may fail to be
applied following modification of the underwing longeron, compromising
the required fault tolerance of the fuel tank lightning protection
design. For those airplanes, this AD requires application of a cap seal
of the correct sealant type to the minimum thickness or greater, if not
already done.
Second, certain other groups and configurations have no thickness
requirement for the applied cap seal, and the requirements bulletin
mistakenly refers to the Boeing Standard Overhaul Practices Manual
(SOPM) section 20-50-19 for procedures to apply the cap seal. The SOPM
procedure specifies a thickness that is half the necessary thickness,
while the Boeing Model 777 aircraft maintenance manual (AMM) procedure,
which is also referred to in the requirements bulletin, specifies the
correct thickness for cap seals. It is also possible that operators may
have used an accepted method other than that specified in the SOPM and
AMM, as no specific procedure was required by the requirements
bulletin. A cap seal of insufficient thickness may fail to contain a
spark resulting from a lightning strike, similarly compromising
[[Page 60113]]
the fault tolerance of the fuel tank lightning protection. This AD
specifies the minimum thickness and sealant type for an applied cap
seal, and requires replacement of any seal that was previously applied
using a procedure that specifies an inadequate thickness.
Third, some structural inspections described by the requirements
bulletin may require the removal of certain fastener cap seals;
however, the requirements bulletin either does not require that the cap
seal be replaced, or does not provide a thickness requirement for the
replaced seal. These errors affect the fuel tank lightning protection
for the same reasons as already described. This AD requires that any
seal removed for the inspections required by the requirements bulletin
be replaced with a cap seal of correct sealant type and adequate
thickness.
Therefore, for airplanes on which the actions of the requirements
bulletin have not yet been accomplished, and for airplanes for which
this AD requires rework of already applied cap seals, those cap sealing
differences are defined in paragraph (h) of this AD as exceptions to
the requirements bulletin. For airplanes on which the actions of the
requirements bulletin have been accomplished but a maintenance records
check cannot conclusively determine that an appropriate procedure was
used to apply the cap seals, paragraph (i) of this AD requires rework
of the applied cap seals.
This AD also corrects and clarifies other aspects of AD 2022-18-11
as follows.
Following the publication of AD 2022-18-11, the FAA and
manufacturer discovered that Model 777-200 airplanes that do not have a
fuel tank in the area affected by the unsafe condition were erroneously
included in the applicability of AD 2022-18-11. As the design of these
airplanes does not allow fuel to be present in the affected area
(between the side-of-body ribs), the unsafe condition is not present on
these airplanes. These airplanes are now identified in this AD by their
maximum taxi weight of 547,000 pounds or less. Model 777-200 airplanes
greater than 547,000 pounds maximum taxi weight, commonly referred to
as ``777-200ERs'' (extended range), remain affected by the unsafe
condition. Since the issuance of AD 2022-18-11, the manufacturer has
also implemented a design change in production to address the unsafe
condition. As a result, the unsafe condition does not exist on Model
777F airplanes having manufacturer line numbers 1743 and subsequent.
Paragraph (c) of this AD, Applicability, has been revised accordingly.
In addition, the effectivity of the manufacturer's requirements
bulletin also has the potential to cause confusion regarding the
required actions for certain Model 777F airplanes. These airplanes,
Model 777Fs having line numbers 1713, 1717, 1720, and 1724 through 1742
inclusive were not included in the effectivity of the requirements
bulletin. While these airplanes were included in the applicability of
AD 2022-18-11 and remain included in the applicability of this AD, the
specific instructions applicable to them were not clearly identified in
the requirements bulletin. Paragraph (h)(7) of this AD clarifies that
Group 6 actions are the applicable actions for these airplanes.
FAA's Determination
The FAA is issuing this AD because the agency has determined the
unsafe condition described previously is likely to exist or develop in
other products of the same type design.
Related Service Information Under 1 CFR Part 51
This AD requires Boeing Alert Requirements Bulletin 777-57A0122 RB,
dated October 8, 2021, which the Director of the Federal Register
approved for incorporation by reference as of October 31, 2022 (87 FR
58259, dated September 26, 2022). This service information 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.
AD Requirements
This AD requires accomplishing the actions specified in the service
information already described, except for any differences identified as
exceptions in the regulatory text of this AD. This AD also requires
reviewing the maintenance records of previously modified airplanes to
determine the procedure used to apply cap seals, and applying and
replacing certain cap seals using new specified thickness dimensions.
Justification for Immediate Adoption and Determination of the Effective
Date
Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
because a cap seal below the minimum thickness may fail to contain
arcing at a fastener penetrating the center wing fuel tank during a
lightning strike, potentially creating an ignition source within the
fuel tank and leading to a fuel tank explosion. Accordingly, notice and
opportunity for prior public comment are impracticable and contrary to
the public interest pursuant to 5 U.S.C. 553(b)(3)(B).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forgo notice and
comment.
Comments Invited
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include ``Docket No. FAA-2023-1814 and Project Identifier
AD-2023-00773-T'' at the beginning of your comments. The most helpful
comments reference a specific portion of the final rule, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this final rule because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
<a href="http://regulations.gov">regulations.gov</a>, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this final rule.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this AD contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and
[[Page 60114]]
that is relevant or responsive to this AD, it is important that you
clearly designate the submitted comments as CBI. Please mark each page
of your submission containing CBI as ``PROPIN.'' The FAA will treat
such marked submissions as confidential under the FOIA, and they will
not be placed in the public docket of this AD. Submissions containing
CBI should be sent to Kevin Nguyen, Aviation Safety Engineer, FAA, 2200
South 216th St., Des Moines, WA 98198; phone: 206-231-3555; email:
<a href="/cdn-cgi/l/email-protection#400b2536292e6e0e273539252e002621216e272f36"><span class="__cf_email__" data-cfemail="95def0e3fcfbbbdbf2e0ecf0fbd5f3f4f4bbf2fae3">[email protected]</span></a>. Any commentary that the FAA receives that is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 291 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
----------------------------------------------------------------------------------------------------------------
Inspection(s) (retained actions 44 work-hours x $85 $0 $3,740 per $1,088,340 per
from AD 2022-18-11). per hour = $3,740 inspection cycle. inspection cycle.
per inspection
cycle.
Modification* (retained actions 137 work-hours x 47,964 $59,609............ $17,346,219.
from AD 2022-18-11). $85 per hour =
$11,645.
Post-modification inspection(s)* 46 work-hours x $85 0 $3,910 per $1,137,810 per
(retained actions from AD 2022- per hour = $3,910 inspection cycle. inspection cycle.
18-11). per inspection
cycle.
Maintenance records review* (new 1 work-hour x $85 85 $85................ Up to $24,735.
action). per hour = $85.
----------------------------------------------------------------------------------------------------------------
*Number of affected airplanes that will be required to do this action is unknown.
The FAA estimates the following costs to do any necessary cap
sealing that would be required based on the results of the maintenance
records review. The FAA has no way of determining the number of
aircraft that might need the cap sealing:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product
----------------------------------------------------------------------------------------------------------------
Cap sealing............................ Up to 109 work-hours x $85 $90 Up to $9,355.
per hour = Up to $9,265.
----------------------------------------------------------------------------------------------------------------
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.
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, and
(2) Will not affect intrastate aviation in Alaska.
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:
0
a. Removing Airworthiness Directive (AD) 2022-18-11, Amendment 39-22162
(87 FR 58259, September 26, 2022); and
0
b. Adding the following new AD:
2023-17-14 The Boeing Company: Amendment 39-22541; Docket No. FAA-
2023-1814; Project Identifier AD-2023-00773-T.
(a) Effective Date
This airworthiness directive (AD) is effective September 15,
2023.
[[Page 60115]]
(b) Affected ADs
This AD replaces AD 2022-18-11, Amendment 39-22162 (87 FR 58259,
September 26, 2022) (AD 2022-18-11).
(c) Applicability
This AD applies to all The Boeing Company Model 777-200, -200LR,
-300, -300ER, and 777F series airplanes, certificated in any
category, excluding the airplanes identified in paragraphs (c)(1)
and (2) of this AD.
(1) Boeing Model 777-200 series airplanes having a maximum taxi
weight equal to or less than 547,000 pounds.
(2) Boeing Model 777F series airplanes with manufacturer line
numbers of 1743 and subsequent.
(d) Subject
Air Transport Association (ATA) of America Code 57, Wings.
(e) Unsafe Condition
This AD was prompted by a report of a crack found in a front
spar lower chord undergoing an underwing longeron replacement, and
the determination that AD 2022-18-11 did not specify the appropriate
thickness for the application of cap seals to fasteners penetrating
the center wing fuel tank. The FAA is issuing this AD to detect and
correct such cracking, which in combination with cracking in the
front spar web, could result in a fuel leak and fire hazard. In
addition, cap seals applied below the necessary thickness may fail
to contain a spark resulting from a lightning strike, possibly
resulting in a fuel tank explosion.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Retained Required Actions, With No Changes
This paragraph restates the requirements of paragraph (g) of AD
2022-18-11, with no changes. Except as specified by paragraph (h) of
this AD: At the applicable times specified in the ``Compliance''
paragraph of Boeing Alert Requirements Bulletin 777-57A0122 RB,
dated October 8, 2021, do all applicable actions identified in, and
in accordance with, the Accomplishment Instructions of Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021. Actions
identified as terminating action in Boeing Alert Requirements
Bulletin 777-57A0122 RB, dated October 8, 2021, terminate the
applicable required actions of this AD, provided the terminating
action is done in accordance with the Accomplishment Instructions of
Boeing Alert Requirements Bulletin 777-57A0122 RB, dated October 8,
2021.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
777-57A0122, dated October 8, 2021, which is referred to in Boeing
Alert Requirements Bulletin 777-57A0122 RB, dated October 8, 2021.
(h) Exceptions to Service Information Specifications
(1) Where the Compliance Time columns of the tables in the
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
57A0122 RB, dated October 8, 2021, use the phrase ``the original
issue date of Requirements Bulletin 777-57A0122 RB,'' this AD
requires replacing those words with ``October 31, 2022, the
effective date of AD 2022-18-11.''
(2) Where Boeing Alert Requirements Bulletin 777-57A0122 RB,
dated October 8, 2021, specifies contacting Boeing for repair
instructions: This AD requires repair using a method approved in
accordance with the procedures specified in paragraph (j) of this
AD.
(3) Where the ``Compliance'' paragraph of Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021, uses
the phrase ``Tables 1 through 50,'' this AD requires replacing those
words with ``Tables 1 through 54.''
(4) During application of any cap seal to a fastener, fastener
head, and fastener threads and collars, as required by this AD, the
cap seal must be applied with a thickness equal to or greater than
the dimensions specified in figure 1 to paragraph (h)(4) of this AD.
Figure 1 to paragraph (h)(4)--Cap seal minimum thickness (all
dimensions in inches)
[GRAPHIC] [TIFF OMITTED] TR31AU23.000
(5) Boeing Alert Requirements Bulletin 777-57A0122 RB, dated
October 8, 2021, does not require the application of cap seals to
underwing longeron fasteners, fastener heads, and fastener threads
and collars for the airplane groups and configurations
[[Page 60116]]
identified in paragraphs (h)(5)(i) through (iv) of this AD. For
those airplane groups and configurations, however, this AD requires
application of a cap seal to the underwing longeron fasteners at the
locations identified in Figures 81 and 144 of Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021, during
installation of the underwing longeron.
(i) Groups 7 and 8, Configurations 5 through 8, on the left
side.
(ii) Group 9, Configurations 1 and 2, on the left side.
(iii) Groups 7 and 8, Configurations 2, 6, 10, and 14, on the
right side.
(iv) Group 9, Configurations 1 and 3, on the right side.
(6) Where Boeing Alert Requirements Bulletin 777-57A0122 RB,
dated October 8, 2021, requires inspections that may require the
removal of fastener cap seals, this AD requires that if the cap seal
is removed, a cap seal of BMS 5-45 sealant be reapplied with a
thickness equal to or greater than the dimensions specified in
figure 1 to paragraph (h)(4) of this AD before further flight after
completion of the inspection.
(7) The Effectivity of Boeing Alert Requirements Bulletin 777-
57A0122 RB, dated October 8, 2021, does not include Boeing Model
777F series airplanes having line numbers 1713, 1717, 1720, and 1724
through 1742 inclusive. However, for those airplanes, this AD
requires accomplishment of the applicable actions specified in the
Boeing Alert Requirements Bulletin for Group 6.
(i) Actions for Previously Modified Airplanes
For airplanes on which the applicable actions of Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021, have
been accomplished before the effective date of this AD: Within 30
days after the effective date of this AD, review the maintenance
records to determine the procedures used to apply cap seals during
accomplishment of the actions in Boeing Alert Requirements Bulletin
777-57A0122 RB, dated October 8, 2021.
(1) If all of the conditions specified in paragraphs (i)(1)(i)
through (iii) of this AD are met, no further work is required by
paragraph (i) of this AD.
(i) If the underwing longeron was removed for any reason during
accomplishment of the actions in Boeing Alert Requirements Bulletin
777-57A0122 RB, dated October 8, 2021, a cap seal was applied to the
underwing longeron fasteners, fastener threads, and fastener collars
at the locations identified in Figures 81 and 144 of Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021, during
installation.
(ii) All cap seals were applied using procedures with thickness
dimensions greater than or equal to those given in figure 1 to
paragraph (h)(4) of this AD.
(iii) All cap seals that were removed to accomplish any
inspection in accordance with Boeing Alert Requirements Bulletin
777-57A0122 RB, dated October 8, 2021, were replaced with cap seals
of BMS 5-45 sealant of thickness dimensions greater than or equal to
those given in figure 1 to paragraph (h)(4) of this AD.
(2) If any cap seal was applied using procedures with thickness
dimensions less than those given in figure 1 to paragraph (h)(4) of
this AD, or if the maintenance records do not definitively specify
the procedures used: At the applicable time specified in paragraph
(i)(2)(i) or (ii) of this AD, replace the cap seal in accordance
with the Accomplishment Instructions of Boeing Alert Requirements
Bulletin 777-57A0122 RB, dated October 8, 2021, using a cap sealing
procedure with thickness greater than or equal to the dimensions
given in figure 1 to paragraph (h)(4) of this AD.
(i) For airplanes equipped with a flammability reduction means
approved by the FAA as compliant with the fuel tank flammability
reduction (FTFR) requirements of 14 CFR 25.981(b) or 26.33(c)(1), or
an ignition mitigation means approved by the FAA as compliant with
the FTFR requirements of 14 CFR 25.981(c) or 26.33(c)(2): Within 180
days after the effective date of this AD,
(ii) For airplanes not described in paragraph (i)(2)(i) of this
AD: Within 90 days after the effective date of this AD.
(3) For any cap seal that was not applied, or for any cap seal
that was removed for inspections and not replaced, or if the
maintenance records do not definitively specify the procedures used:
At the applicable time specified in paragraph (i)(3)(i) or (ii) of
this AD, apply a cap seal of BMS 5-45 sealant using an accepted
method with thickness greater than or equal to the dimensions given
in figure 1 to paragraph (h)(4) of this AD.
Note 2 to paragraph (i)(3): Guidance for applying a cap seal
can be found in the Boeing Model 777 Aircraft Maintenance Manual
section 28-11-00.
(i) For airplanes equipped with a flammability reduction means
approved by the FAA as compliant with the fuel tank flammability
reduction (FTFR) requirements of 14 CFR 25.981(b) or 26.33(c)(1), or
an ignition mitigation means approved by the FAA as compliant with
the FTFR requirements of 14 CFR 25.981(c) or 26.33(c)(2): Within 180
days after the effective date of this AD.
(ii) For airplanes not described in paragraph (i)(3)(i) of this
AD: Within 90 days after the effective date of this AD.
(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 certification office,
send it to the attention of the person identified in paragraph (k)
of this AD. Information may be emailed to: <a href="/cdn-cgi/l/email-protection#3d04107c7370106e585c49495158107c7e72107c70727e106f584c48584e494e7d5b5c5c135a524b"><span class="__cf_email__" data-cfemail="093024484744245a6c687d7d656c24484a46244844464a245b6c787c6c7a7d7a496f6868276e667f">[email protected]</span></a>.
(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.
(4) AMOCs approved for AD 2022-18-11 are approved as AMOCs for
the corresponding provisions of Boeing Alert Requirements Bulletin
777-57A0122 RB, dated October 8, 2021, that are required by
paragraph (g) of this AD.
(k) Related Information
For more information about this AD, contact Kevin Nguyen,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 206-231-3555; email: <a href="/cdn-cgi/l/email-protection#2e654b5847400060495b574b406e484f4f00494158"><span class="__cf_email__" data-cfemail="7f341a0916115131180a061a113f191e1e51181009">[email protected]</span></a>.
(l) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the service information listed
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do
the actions required by this AD, unless this AD specifies otherwise.
(3) The following service information was approved for IBR on
October 31, 2022 (87 FR 58259, dated September 26, 2022).
(i) Boeing Alert Requirements Bulletin 777-57A0122 RB, dated
October 8, 2021.
(ii) [Reserved]
(4) For service information 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; internet <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
(5) You may view this service information 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.
(6) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, email <a href="/cdn-cgi/l/email-protection#dcbaaef2b5b2afacb9bfa8b5b3b29cb2bdaebdf2bbb3aa"><span class="__cf_email__" data-cfemail="8ee8fca0e7e0fdfeebedfae7e1e0cee0effcefa0e9e1f8">[email protected]</span></a>, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on August 28, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2023-18835 Filed 8-28-23; 4:15 pm]
BILLING CODE 4910-13-P
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</html>Indexed from Federal Register on August 31, 2023.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.