[Federal Register Volume 89, Number 61 (Thursday, March 28, 2024)]
[Proposed Rules]
[Pages 21446-21450]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-06522]
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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]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain The Boeing Company Model 777 airplanes. This proposed AD
was prompted by a report indicating multiple findings of cracks in the
fuselage skin common to the underwing longeron (UWL). This proposed AD
would 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
proposing this AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by May 13,
2024.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to regulations.gov. Follow
the instructions for submitting comments.
Fax: 202-493-2251.
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.
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 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 NPRM, any comments received, and other
information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
For service information identified in this NPRM, 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.
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. It is also available at
regulations.gov by searching for and locating 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: [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2024-0769; Project Identifier
AD-2023-00556-T'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, 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 proposal 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
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this NPRM.
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 NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, 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 NPRM. Submissions containing CBI should be sent to Luis
Cortez-Muniz Aviation Safety Engineer, FAA, 2200 South 216th St., Des
Moines, WA 98198; phone: 206-231-3958; email: [email protected]. Any commentary that the FAA receives that is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.
Background
The FAA has received reports indicating multiple findings of cracks
in the fuselage skin common to the UWL on all series of Boeing Model
777 airplanes. The crack findings were made during UWL replacement or
accomplishing Boeing Service Bulletins 777-53-0084 or 777-53-0087, or
Boeing Requirements Bulletin 777-57A0122 RB. In many of the fuselage
skin crack reports, the UWL was reported not damaged. The found
fuselage skin cracks were hidden externally by the UWL, and internally
by fuselage frames and stringers. The fuselage skin cracks were found
on airplanes with as few as 2,000 total flight cycles and 18,000 total
flight hours. These fuselage skin cracks were determined to be 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. These conditions, 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.
Boeing has issued Boeing Alert Requirements Bulletin 777-53A0100
[[Page 21447]]
RB, dated March 16, 2023, to address the identified unsafe condition.
Other Relevant Rulemaking
AD 2023-17-14, Amendment 39-22541 (88 FR 60111, August 31, 2023)
(AD 2023-17-14) requires 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
UWL located at station (STA) 1035; modification of the front spar lower
chord for some airplanes; repetitive post-modification inspections; and
applicable on-condition actions, as specified in Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021; and
requires a maintenance records review of previously modified airplanes
for the procedures used during that modification, and applicable
corrective actions. Boeing Alert Requirements Bulletin 777-53A0100 RB,
dated March 16, 2023, specifies that the modification in Boeing Alert
Requirements Bulletin 777-57A0122 RB should be done before further
flight if cracking is found during certain inspections. Therefore, this
proposed AD, which mandates Boeing Alert Requirements Bulletin 777-
53A0100 RB, dated March 16, 2023, might require that the modification
be done prior to the compliance time for that modification as specified
in 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 paragraph (g) of this
proposed 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.
AD 2019-11-02, Amendment 39-19648 (84 FR 28722, June 20, 2019) (AD
2019-11-02) requires repetitive inspections of the left and right side
UWLs and applicable on-condition actions as specified in Boeing Alert
Service Bulletin 777-53A0081, Revision 2, dated March 29, 2019. 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; or the
front spar lower chord modification specified in Boeing Alert
Requirements Bulletin 777-57A0122 RB, dated October 8, 2021; which must
be done if cracking is found during certain inspections specified in
Boeing Alert Requirements Bulletin 777-53A0100 RB, dated March 16,
2023, terminates the inspection requirements of paragraph (g) of AD
2019-11-02 for the applicable side (left or right) on which the
modification was done.
FAA's Determination
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 777-53A0100 RB,
dated March 16, 2023. This service information 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. Initial
compliance times for post-modification inspections range from within
10,000 flight cycles or 50,000 flight hours, whichever occurs first
after the modification; and within 30,000 flight cycles, 90,000 flight
hours, or before the result of a certain total flight cycle and total
flight hour equation, whichever occurs first after the modification.
The repetitive intervals range from 8,000 flight cycles or 25,000
flight hours, whichever occurs first, to 11,000 flight cycles or 56,000
flight hours, whichever occurs first. Repairs of cracking found during
post-modification inspections are to be accomplished before further
flight.
The FAA also reviewed Boeing Multi Operator Message MOM-MOM-24-
0054-01B, dated January 26, 2024. This service information 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 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 ADDRESSES.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the service information already described and except for any
differences identified as exceptions in the regulatory text of this
proposed AD. For information on the procedures and compliance times,
see this service information at regulations.gov under Docket No. FAA-
2024-0769.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 272 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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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.
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The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of the
proposed inspection. The agency has no way of determining the number of
aircraft that might need these actions:
[[Page 21448]]
On-Condition Costs
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Action Labor cost Parts cost Cost per product
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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.
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The FAA has received no definitive data on which to base the cost
estimates for the on-condition repairs specified in this proposed 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 proposed 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
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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 Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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:
The Boeing Company: Docket No. FAA-2024-0769; Project Identifier AD-
2023-00556-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 13, 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
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 Service Information 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.
(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, for this AD, during
application of any cap seal to a fastener, fastener head, or
fastener threads and collars, 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.
[[Page 21449]]
Figure 1 to Paragraph (h)(3)--Cap Sealing Dimensions (all Dimensions
are in Inches)
[GRAPHIC] [TIFF OMITTED] TP28MR24.025
(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 3 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 4 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
[[Page 21450]]
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: [email protected].
(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: [email protected].
(2) Service information identified in this AD that is not
incorporated by reference is available at the addresses 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 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 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 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; 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 [email protected].
Issued on March 22, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2024-06522 Filed 3-27-24; 8:45 am]
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