[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1882; Project Identifier AD-2024-00227-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for certain
The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C,
747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, and 747SR series airplanes.
This proposed AD was prompted by a report indicating cracks at eight fastener hole
locations in the fuselage skin lap splice between certain stations (STAs) at certain
stringers. This proposed AD would require repetitive inspections of the upper fastener
row of the fuselage skin lap splice in a certain area for any crack, and applicable oncondition 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 [INSERT DATE 45
DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
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. FAA2024-1882; 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 the 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.
• 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-2024-1882.
FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3964;
email: Stefanie.N.Roesli@faa.gov.
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 the ADDRESSES section.
Include “Docket No. FAA-2024-1882; Project Identifier AD-2024-00227-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 Stefanie Roesli,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone:
206-231-3964; email: Stefanie.N.Roesli@faa.gov. 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 a report that cracking was found at eight fastener hole
locations in the fuselage skin lap splice between STAs 1450 and 1470 at stringers S-23L

and S-23R on a Boeing Model 747-400 series airplane that had completed 128,792 flight
hours and 25,581 flight cycles when the cracks were discovered. The maximum crack
length discovered was 0.946 inch. After this report was received, the Boeing Company
did a high frequency eddy current inspection on the Boeing Model 747-100 fatigue test
airplane and found cracks on the countersink area of the fastener holes on the lap splice
between STAs 1416 and 1480 at stringers S-23L and S-23R. The maximum crack length
discovered was 0.10 inch. The Boeing Model 747-100 fatigue test airplane had completed
the equivalent of 45,000 flight cycles. Cracking in the fuselage skin lap splice, if not
addressed, could result in an in-flight rapid decompression and a loss of structural
integrity of the fuselage.
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 Material under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 747-53A2912 RB, dated
April 5, 2024. This material specifies procedures for repetitive external surface high
frequency eddy current inspections of the upper fastener row of the fuselage skin lap
splice between STAs 1350 and 1480 at stringers S-23L and S-23R for any crack, and
applicable on-condition actions. On-condition actions include obtaining and following
repair instructions.
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.

Proposed AD Requirements in this NPRM
This proposed AD would require accomplishing the actions specified in the
material already described, 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 material at regulations.gov under Docket No. FAA-2024-1882.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 170
airplanes of U.S. registry. The FAA estimates the following costs to comply with this
proposed AD:
Estimated costs
Action

Labor cost

Parts cost

Cost per
product

Cost on U.S.
operators

Inspections

8 work-hours X $85
per hour = $680 per
inspection cycle

$0

$680 per
inspection
cycle

$115,600 per
inspection
cycle

The FAA has received no definitive data on which to base the cost estimates for
the on-condition actions specified in this proposed AD.
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
The Boeing Company: Docket No. FAA-2024-1882; Project Identifier AD-2024-00227T.

(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by
[INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL
REGISTER].
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP,
and 747SR series airplanes, certificated in any category, as identified in Boeing Alert
Requirements Bulletin 747-53A2912 RB, dated April 5, 2024.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by a report indicating cracks at eight fastener hole
locations in the fuselage skin lap splice between stations (STAs) 1450 and 1470 at
stringers S-23L and S-23R. The FAA is issuing this AD to detect and correct cracking of
the upper fastener row of the fuselage skin lap splice between STAs 1350 and 1480 at
stringers S-23L and S-23R. The unsafe condition, if not addressed, could result in an inflight rapid decompression and a loss of structural integrity of the fuselage.
(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 747-53A2912 RB,
dated April 5, 2024, do all applicable actions identified in, and in accordance with, the

Accomplishment Instructions of Boeing Alert Requirements Bulletin 747-53A2912 RB,
dated April 5, 2024.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by
this AD can be found in Boeing Alert Service Bulletin 747-53A2912, dated April 5,
2024, which is referred to in Boeing Alert Requirements Bulletin 747-53A2912 RB,
dated April 5, 2024.
(h) Exceptions to Service Information Specifications
(1) Where the Condition and Boeing Recommended Compliance Time columns
of the tables in the “Compliance” paragraph of Boeing Alert Requirements Bulletin
747-53A2912 RB, dated April 5, 2024, refer to “the Original Issue date of the
Requirements Bulletin 747-53A2912 RB,” this AD requires using the effective date of
this AD.
(2) Where Boeing Alert Requirements Bulletin 747-53A2912 RB, dated April 5,
2024, specifies contacting Boeing for repair instructions: This AD requires doing the
repair using a method approved in accordance with the procedures specified in paragraph
(i) of this AD.
(i) 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 (j)(1) of this AD. Information may be emailed to:
AMOC@faa.gov.

(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.
(j) Related Information
(1) For more information about this AD, contact Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3964;
email: Stefanie.N.Roesli@faa.gov.
(2) Material identified in this AD that is not incorporated by reference is available
at the address specified in paragraph (k)(3) this AD.
(k) 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 747-53A2912 RB, dated April 5, 2024.
(ii) [Reserved]
(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
fr.inspection@nara.gov.
Issued on June 27, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-14608 Filed: 7/2/2024 8:45 am; Publication Date: 7/3/2024]