[Federal Register Volume 88, Number 147 (Wednesday, August 2, 2023)]
[Rules and Regulations]
[Pages 50762-50764]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16366]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0934; Project Identifier AD-2022-01443-T; 
Amendment 39-22503; AD 2023-14-03]
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 747-8F and 747-8 series airplanes. This AD was 
prompted by a report of cracks in stringers, common to the end 
fittings, on the aft side of the bulkhead at station (STA) 2598. This 
AD requires detailed inspections of the stringers, common to the end 
fittings, forward and aft of the bulkhead at a certain station for 
cracking and applicable on-condition actions. The FAA is issuing this 
AD to address the unsafe condition on these products.

DATES: This AD is effective September 6, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 6, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-0934; 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 St., Des Moines, WA. For information on the availability of this 
material at the FAA,

[[Page 50763]]

call 206-231-3195. It is also available at regulations.gov under Docket 
No. FAA-2023-0934.

FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety 
Engineer, FAA, 2200 South 216th St., 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 
(Boeing) Model 747-8F and 747-8 series airplanes. The NPRM published in 
the Federal Register on May 8, 2023 (88 FR 29555). The NPRM was 
prompted by a report indicating the presence of cracks in stringers, 
common to the end fittings, at stringer location S-42L/R and S-46L/R on 
the aft side of the bulkhead at station 2598. The airplane had 
accumulated 5,517 total flight cycles and 32,468 total flight hours at 
time the cracks were found. In addition, during foreign object debris 
(FOD) inspections Boeing found five cracks in stringers, common to the 
end fittings, at stringer locations S-2L, S-6L, S-8L, and S-2R on the 
forward side and S-5L on the aft side of the bulkhead at STA 2598 on 
two airplanes. The FAA has also received reports of similar cracks 
found on additional airplanes. In all cases, the cracks were found in 
the side walls of the stringers and had grown in longitudinal and 
transverse directions, but there was no other damage or deformation in 
the surrounding area. An investigation by Boeing found that during 
airplane assembly, un-shimmed or incorrectly shimmed gaps that 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 detailed 
inspections of the stringers, common to the end fittings, forward and 
aft of the bulkhead at a certain station for cracking and applicable 
on-condition actions. The FAA is issuing this AD to address stress 
corrosion cracking in the stringers. This condition, if not addressed, 
could lead to a failure of the skin adjacent to the bulkhead at STA 
2598, which could adversely affect the structural integrity of the 
airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from Boeing, who supported the NPRM 
without change.

Conclusion

    The FAA reviewed the relevant data, considered the comment 
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 747-53A2911 RB, 
dated November 3, 2022. This service information specifies procedures 
for repetitive detailed inspections of the stringers, common to the end 
fittings, forward and aft of the bulkhead at STA 2598, for any crack, 
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.

Costs of Compliance

    The FAA estimates that this AD affects 42 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
----------------------------------------------------------------------------------------------------------------
Detailed inspection.............  91 work-hours x $85              $0   $7,735 per           $324,870 per
                                   per hour = $7,735                     inspection cycle.    inspection cycle.
                                   per inspection
                                   cycle.
----------------------------------------------------------------------------------------------------------------

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

                                               On-condition Costs
----------------------------------------------------------------------------------------------------------------
                 Action                          Labor cost             Parts cost         Cost per product
----------------------------------------------------------------------------------------------------------------
Repair.................................  13 work-hours x $85 per               $600   $1,705 (per stringer).
                                          hour = $1,105.
----------------------------------------------------------------------------------------------------------------

    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

[[Page 50764]]

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:

2023-14-03 The Boeing Company: Amendment 39-22503; Docket No. FAA-
2023-0934; Project Identifier AD-2022-01443-T.

(a) Effective Date

    This airworthiness directive (AD) is effective September 6, 
2023.

(b) Affected ADs

    None.

 (c) Applicability

    This AD applies to all The Boeing Company Model 747-8F and 747-8 
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 a report of cracks in stringers, common 
to the end fittings, on the aft side of the bulkhead at station 
(STA) 2598. The FAA is issuing this AD to address stress corrosion 
cracking in the stringers. This condition, if not addressed, could 
lead to a failure of the skin adjacent to the bulkhead at STA 2598, 
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 747-53A2911 RB, dated November 3, 2022, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
747-53A2911 RB, dated November 3, 2022.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
747-53A2911, dated November 3, 2022, which is referred to in Boeing 
Alert Requirements Bulletin 747-53A2911 RB, dated November 3, 2022.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time column of the table in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 747-
53A2911 RB, dated November 3, 2022, uses the phrase ``the original 
issue date of Requirements Bulletin 747-53A2911 RB,'' this AD 
requires using ``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 747-53A2911 RB, 
dated November 3, 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) 
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

    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: [email protected].

(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 747-53A2911 RB, dated 
November 3, 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 St., 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 July 8, 2023.
Michael Linegang,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-16366 Filed 8-1-23; 8:45 am]
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