[Federal Register Volume 87, Number 168 (Wednesday, August 31, 2022)]
[Proposed Rules]
[Pages 53419-53421]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-18759]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
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  Federal Register / Vol. 87, No. 168 / Wednesday, August 31, 2022 / 
Proposed Rules  

[[Page 53419]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0874; Project Identifier AD-2022-00337-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 DC-9-81 (MD-81), DC-9-82 (MD-82), 
DC-9-83 (MD-83), and DC-9-87 (MD-87) airplanes; and Model MD-88 
airplanes. This proposed AD was prompted by an evaluation by the design 
approval holder (DAH) indicating that certain center wing lower 
stringers are subject to widespread fatigue damage (WFD). WFD analysis 
found that fatigue cracks could grow to a critical length after the 
structural modification point (SMP) for these center wing lower 
stringers. This proposed AD would require replacing certain left and 
right side center wing lower stringers. 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 October 17, 
2022.

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 https://www.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.
    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; internet https://www.myboeingfleet.com. You may 
view this referenced 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 https://www.regulations.gov by searching for and locating Docket No. FAA-2022-
0874.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2022-0874; 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.

FOR FURTHER INFORMATION CONTACT: Sean Newell, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5266; 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-2022-0874; Project Identifier 
AD-2022-00337-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 
https://www.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 Sean 
Newell, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO 
Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-
627-5266; 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

    Fatigue damage can occur locally, in small areas or structural 
design details, or globally, in widespread areas. Multiple-site damage 
is widespread damage that occurs in a large structural element such as 
a single rivet line of a lap splice joining two large skin panels. 
Widespread damage can also occur in multiple elements such as adjacent 
frames or stringers. Multiple-site damage and multiple-element damage 
cracks are typically too small initially to be reliably detected with 
normal inspection methods. Without intervention, these cracks will 
grow, and eventually compromise the structural integrity of the 
airplane. This condition is known as WFD. It is associated with general 
degradation of large areas of structure with similar

[[Page 53420]]

structural details and stress levels. As an airplane ages, WFD will 
likely occur, and will certainly occur if the airplane is operated long 
enough without any intervention.
    An FAA final rule (``Aging Airplane Program: Widespread Fatigue 
Damage;'' 75 FR 69746, November 15, 2010) became effective on January 
14, 2011, and amended 14 CFR parts 25, 26, 121, and 129 (commonly known 
as the WFD rule). The WFD rule requires certain actions to prevent 
structural failure due to WFD throughout the operational life of 
certain existing transport category airplanes and all of these 
airplanes that will be certificated in the future. DAHs of existing and 
future airplanes subject to the WFD rule are required to establish a 
limit of validity (LOV) of the engineering data that support the 
structural maintenance program. Operators affected by the WFD rule may 
not fly an airplane beyond its LOV, unless an extended LOV is approved.
    The WFD rule does not require identifying and developing 
maintenance actions if the DAHs can show that such actions are not 
necessary to prevent WFD before the airplane reaches the LOV. Many 
LOVs, however, do depend on accomplishment of future maintenance 
actions. As stated in the WFD rule, any maintenance actions necessary 
to reach the LOV will be mandated by airworthiness directives through 
separate rulemaking actions.
    In the context of WFD, this action is necessary to enable DAHs to 
propose LOVs that allow operators the longest operational lives for 
their airplanes, and still ensure that WFD will not occur. This 
approach allows for an implementation strategy that provides 
flexibility to DAHs in determining the timing of service information 
development (with FAA approval), while providing operators with 
certainty regarding the LOV applicable to their airplanes.
    The FAA has received a report indicating that cracking was found in 
the left and/or right side center wing lower stringers S-13, S-15, S-
16, and S-17. Based on that report, the FAA issued AD 2020-10-10, 
Amendment 39-19913 (85 FR 31046, May 22, 2020) (AD 2020-10-10). AD 
2020-10-10 was prompted by a report of cracks at certain stringers and 
associated end fittings, and skins in the center wing fuel tank where 
the stringers meet the end fittings. AD 2020-10-10 requires repetitive 
inspections for cracking in the left and right side center wing lower 
skin at stringers S-18 through S-20, the fastener holes common to 
stringers S-11 through S-22, and the forward and aft skins, and repair. 
Since the FAA issued AD 2020-10-10, Boeing did additional WFD analysis 
and found that the actions required by AD 2020-10-10 are adequate to 
address the unsafe condition until the airplane reaches the SMP (the 
point in time when a structural area must be modified or replaced to 
preclude WFD) at 81,740 flight cycles. However, fatigue cracks could 
grow to a critical length at any point after the SMP for center wing 
lower stringers S-11 through S-22. If not addressed, undetected fatigue 
cracks in the right or left side center wing lower stringers S-11 
through S-22 between wing stations Xcw=13 and Xcw=15 could grow to a 
critical length after the SMP at 81,740 total flight cycles. Any 
undetected cracks in three or more adjacent stringers in the right or 
left side center wing lower stringers S-11 through S-22 may result in a 
principal structural element's inability to sustain limit load, which 
could adversely affect the structural integrity of the airplane. 
Performing the replacement required by this proposed AD would terminate 
the repetitive inspections required by AD 2020-10-10.

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 MD80-57A246 RB, 
dated December 17, 2021. This service information specifies procedures 
for replacement of the center wing lower stringers S-11 through S-22 
between Xcw=0 and Xcw=121.688, left and right sides.
    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 https://www.regulations.gov by 
searching for and locating Docket No. FAA-2022-0874.

Explanation of Compliance Time

    The compliance time for the replacement specified in this proposed 
AD for addressing WFD was established to ensure that discrepant 
structure is replaced before WFD develops in airplanes. Standard 
inspection techniques cannot be relied on to detect WFD before it 
becomes a hazard to flight. The FAA will not grant any extensions of 
the compliance time to complete any AD-mandated service bulletin 
related to WFD without extensive new data that would substantiate and 
clearly warrant such an extension.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 22 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replacement...........................  1,572 work-hours x $85          $216,000        $349,620      $7,691,640
                                         per hour = $133,620.
----------------------------------------------------------------------------------------------------------------

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

[[Page 53421]]

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-2022-0874; Project Identifier AD-
2022-00337-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by October 17, 2022.

(b) Affected ADs

    This AD affects AD 2020-10-10, Amendment 39-19913 (85 FR 31046, 
May 22, 2020) (AD 2020-10-10).

(c) Applicability

    This AD applies to The Boeing Company Model DC-9-81 (MD-81), DC-
9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) airplanes; and 
Model MD-88 airplanes, certificated in any category, as identified 
in Boeing Alert Requirements Bulletin MD80-57A246 RB, dated December 
17, 2021.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by an evaluation by the design approval 
holder (DAH) indicating that the center wing lower stringers S-11 
through S-22 are subject to widespread fatigue damage (WFD). The FAA 
is issuing this AD to address fatigue cracking of the right and left 
side center wing lower stringers S-11 through S-22 between wing 
stations Xcw=13 and Xcw=15. If not addressed, undetected fatigue 
cracks could grow to a critical length after the structural 
modification point (SMP) at 81,740 total flight cycles. Any 
undetected cracks in three or more adjacent stringers in the right 
or left side center wing lower stringers S-11 through S-22 may 
result in a principal structural element's inability 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 MD80-57A246 RB, dated December 17, 2021, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
MD80-57A246 RB, dated December 17, 2021.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
MD80-57A246, dated December 17, 2021, which is referred to in Boeing 
Alert Requirements Bulletin MD80-57A246 RB, dated December 17, 2021.

(h) Exceptions to Service Information Specifications

    Where Boeing Alert Requirements Bulletin MD80-57A246 RB, dated 
December 17, 2021, specifies contacting Boeing for replacement 
instructions: This AD requires doing the replacement using a method 
approved in accordance with the procedures specified in paragraph 
(i) of this AD.

(i) Terminating Action for AD 2020-10-10

    Accomplishment of the replacement specified in the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
MD80-57A246 RB, dated December 17, 2021, terminates all of the 
requirements of AD 2020-10-10.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO 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)(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, Los 
Angeles ACO 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 Sean Newell, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5266; email: [email protected].
    (2) 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 https://www.myboeingfleet.com. You may view this referenced 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.

    Issued on July 8, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-18759 Filed 8-30-22; 8:45 am]
BILLING CODE 4910-13-P


