[Federal Register Volume 88, Number 138 (Thursday, July 20, 2023)]
[Rules and Regulations]
[Pages 46679-46681]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-15297]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0432; Project Identifier AD-2022-01384-T; 
Amendment 39-22457; AD 2023-11-11]
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 all 
The Boeing Company Model 747-8 and 747-8F series airplanes. This AD was 
prompted by reports of cracks in stringers, common to the end fittings, 
forward and aft of the pressure bulkhead at station (STA) 2360 at 
multiple stringer locations. This AD requires repetitive inspections of 
stringer sidewalls and certain stringer assemblies, common to the end 
fittings, forward and aft of the pressure bulkhead at STA 2360 for any 
crack, and applicable on-condition actions. The FAA is issuing this AD 
to address the unsafe condition on these products.

DATES: This AD is effective August 24, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of August 24, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-0432; 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:
     For service information identified in this final rule, 
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 Street, 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-2023-0432.

FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
206-231-3964; email: [email protected].

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 all The Boeing Company 
Model 747-8 and 747-8F series airplanes. The NPRM published in the 
Federal Register on April 6, 2023 (88 FR 20431). The NPRM was prompted 
by reports of cracks in the stringers, common to the end fittings, 
forward and aft of the pressure bulkhead at STA 2360. An investigation 
found that during airplane assembly, un-shimmed or incorrectly shimmed 
gaps, which were larger than engineering requirements, caused excessive 
and sustained internal tensile stresses and resulted in stress 
corrosion cracking in the stringers. In the NPRM, the FAA proposed to 
require repetitive inspections of stringer sidewalls and certain 
stringer assemblies, common to the end fittings, forward and aft of the 
pressure bulkhead at STA 2360 for any crack, and applicable on-
condition actions. This condition, if not addressed, could result in an 
undetected crack in the stringers, resulting in the inability of a 
structural element to sustain limit load which could adversely affect 
the structural integrity of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from Boeing and an individual who 
supported the NPRM without change.

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, this 
AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 747-53A2910 RB, 
dated September 21, 2022. This service information specifies procedures 
for repetitive low frequency eddy current (LFEC) and high frequency 
eddy current (HFEC) inspections of the stringer sidewalls; repetitive 
detailed inspections of certain stringer assemblies; and applicable on-
condition actions. On-condition actions include repair. 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 section.

Costs of Compliance

    The FAA estimates that this AD affects 44 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                Action                          Labor cost           Parts cost             Cost per product                 Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection of stringers...............  Up to 110 work-hours x                 $0  Up to $9,350 per inspection cycle.  Up to $411,400 per inspection
                                         $85 per hour = Up to                                                           cycle.
                                         $9,350 per inspection
                                         cycle.
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[[Page 46680]]

    The FAA estimates the following costs to do any necessary repairs 
that would be required based on the results of the inspection. The FAA 
has no way of determining the number of aircraft that might need this 
repair:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair of a cracked stringer..................  13 work-hours x $85 per hour =              $600          $1,705
                                                 $1,105.
----------------------------------------------------------------------------------------------------------------

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,
    (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:

2023-11-11 The Boeing Company: Amendment 39-22457; Docket No. FAA-
2023-0432; Project Identifier AD-2022-01384-T.

(a) Effective Date

    This airworthiness directive (AD) is effective August 24, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 747-8 and 747-8F 
series airplanes, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the stringers, 
common to the end fittings, forward and aft of the pressure bulkhead 
at station (STA) 2360 at multiple stringer locations. The FAA is 
issuing this AD to address an undetected crack in the stringers. The 
unsafe condition, if not addressed, could result in the inability of 
a structural element to sustain limit load which could adversely 
affect the structural integrity 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 747-53A2910 RB, dated September 21, 
2022, do all applicable actions identified in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Requirements 
Bulletin 747-53A2910 RB, dated September 21, 2022.

    Note 1 to paragraph (g):  Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
747-53A2910, dated September 21, 2022, which is referred to in 
Boeing Alert Requirements Bulletin 747-53A2910 RB, dated September 
21, 2022.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 747-
53A2910 RB, dated September 21, 2022, use the phrase ``the original 
issue date of Requirements Bulletin 747-53A2910 RB,'' this AD 
requires using ``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 747-53A2910 RB, 
dated September 21, 2022, 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: [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.

(j) Related Information

    (1) For more information about this AD, contact Stefanie Roesli, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: 206-231-3964; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (4) of this AD.

[[Page 46681]]

(k) 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 747-53A2910 RB, dated 
September 21, 2022.
    (ii) [Reserved]
    (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 service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th Street, Des Moines, WA. For information on the 
availability of this material at the FAA, call 206-231-3195.
    (5) 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 protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on June 7, 2023.
Gaetano A. Sciortino,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-15297 Filed 7-19-23; 8:45 am]
BILLING CODE 4910-13-P


