Proposed Rule2021-18068
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 24, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2017-23-02, which applies to certain The Boeing Company Model 737-200, -200C, -300, -400, and -500 series airplanes. AD 2017-23-02 requires repetitive inspections, replacement, and applicable on-condition actions for certain fuselage crown skin panels. Since the FAA issued AD 2017-23-02, certain airplane configurations and inspection locations have been revised and additional airplanes have been determined to be subject to the unsafe condition. This proposed AD would retain the actions in AD 2017-23-02, revise certain airplane configurations and inspection locations, and add airplanes to the applicability. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 161 (Tuesday, August 24, 2021)</title>
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[Federal Register Volume 86, Number 161 (Tuesday, August 24, 2021)]
[Proposed Rules]
[Pages 47260-47264]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-18068]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0665; Project Identifier AD-2021-00270-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 supersede Airworthiness Directive (AD)
2017-23-02, which applies to certain The Boeing Company Model 737-200,
-200C, -300, -400, and -500 series airplanes. AD 2017-23-02 requires
[[Page 47261]]
repetitive inspections, replacement, and applicable on-condition
actions for certain fuselage crown skin panels. Since the FAA issued AD
2017-23-02, certain airplane configurations and inspection locations
have been revised and additional airplanes have been determined to be
subject to the unsafe condition. This proposed AD would retain the
actions in AD 2017-23-02, revise certain airplane configurations and
inspection locations, and add airplanes to the applicability. 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 8,
2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>
by searching for and locating Docket No. FAA-2021-0665.
Examining the AD Docket
You may examine the AD docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-0665; 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: James Guo, Aerospace Engineer,
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5357; fax: 562-627-
5210; email: <a href="/cdn-cgi/l/email-protection#1c767d71796f327b69735c7a7d7d327b736a"><span class="__cf_email__" data-cfemail="462c272b2335682133290620272768212930">[email protected]</span></a>.
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-2021-0665; Project Identifier
AD-2021-00270-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
the 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
<a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposed AD.
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 James
Guo, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch,
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5357;
fax: 562-627-5210; email: <a href="/cdn-cgi/l/email-protection#9df7fcf0f8eeb3fae8f2ddfbfcfcb3faf2eb"><span class="__cf_email__" data-cfemail="294348444c5a074e5c46694f4848074e465f">[email protected]</span></a>. Any commentary that the
FAA receives which 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 widespread fatigue damage (WFD).
It is associated with general degradation of large areas of structure
with similar 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. Design approval
holders (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
[[Page 47262]]
regarding the LOV applicable to their airplanes.
The FAA issued AD 2017-23-02, Amendment 39-19096 (82 FR 52835,
November 15, 2017) (AD 2017-23-02), for certain The Boeing Company
Model 737-200, -200C, -300, -400, and -500 series airplanes. AD 2017-
23-02 was prompted by an evaluation by the DAH indicating that the
fuselage crown skin panels are subject to WFD. AD 2017-23-02 requires
repetitive inspections, replacement, and applicable on-condition
actions for certain fuselage crown skin panels. The agency issued AD
2017-23-02 to address cracking in the fuselage crown skin panels.
Multiple adjacent cracks in the fuselage crown skin could link up and
lead to decompression or loss of structural integrity of the airplane.
Actions Since AD 2017-23-02 Was Issued
Since the FAA issued AD 2017-23-02, errors were found in Boeing
Alert Service Bulletin 737-53A1358, dated April 27, 2017, which is
referenced in AD 2017-23-02. These errors include airplanes that are
incorrectly identified as being in certain groups, and inspection
figures that show incorrect chem-mill locations. Additional airplanes
were also identified as being subject to the unsafe condition. These
errors affect operators' ability to comply with AD 2017-23-02, and the
FAA determined that a supersedure was needed to require corrected
service information.
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 Service Bulletin 737-53A1358,
Revision 1, dated February 26, 2021. This service information specifies
procedures for repetitive non-destructive inspections for cracking,
replacement of certain fuselage crown skin panels, and applicable on-
condition actions. On-condition actions include a general visual
inspection of certain repairs for any loose or missing fasteners, a low
frequency eddy current (LFEC) inspection of certain repairs for
cracking, and 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 the ADDRESSES section.
Proposed AD Requirements in This NPRM
Although this proposed AD does not explicitly restate the
requirements of AD 2017-23-02, this AD would retain all of the
requirements of AD 2017-23-02. Those requirements are referenced in the
service information identified previously, which, in turn, is
referenced in paragraph (h) of this proposed AD. This proposed AD would
revise certain airplane configurations and inspection locations, and
add airplanes to the applicability. This proposed AD would also require
accomplishment of the actions identified as ``RC'' (required for
compliance) in the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1358, Revision 1, dated February 26, 2021, described
previously, 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a> by searching for and
locating Docket No. FAA-2021-0665.
Explanation of Proposed 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.
Explanation of Proposed Applicability
Model 737 airplanes having line numbers 1 through 291 have an LOV
of 34,000 total flight cycles, and the actions proposed in this NPRM,
as specified in Boeing Alert Service Bulletin 737-53A1358, Revision 1,
dated February 26, 2021, would be required at a compliance time
occurring after that LOV. Although operation of an airplane beyond its
LOV is prohibited by 14 CFR 121.1115 and 129.115, this NPRM would
include those airplanes in the applicability so that these airplanes
are tracked in the event the LOV is extended in the future.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 143 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Inspection..................... Up to 507 work-hours x $0 Up to $43,095 per Up to $6,162,585
$85 per hour = Up to inspection cycle. per inspection
$43,095 per inspection cycle.
cycle.
Replacement.................... 304 work-hours x $85 95,000 $120,840 per skin $17,280,120 per
per hour = $25,840 per panel. skin panel.
skin panel.
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The FAA estimates the following costs to do any necessary
inspections that would be required based on the results of the proposed
inspection. The FAA has no way of determining the number of aircraft
that might need these inspections:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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LFEC inspection............................ 1 work-hours x $85 per hour = $85.. $0 $85
[[Page 47263]]
General visual inspection.................. 1 work-hour x $85 per hour = $85... 0 85
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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.
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 has 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 that the 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:
0
a. Removing Airworthiness Directive (AD) 2017-23-02, Amendment 39-19096
(82 FR 52835, November 15, 2017), and
0
b. Adding the following new AD:
The Boeing Company: Docket No. FAA-2021-0665; Project Identifier AD-
2021-00270-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) action by October 8, 2021.
(b) Affected ADs
This AD replaces AD 2017-23-02, Amendment 39-19096 (82 FR 52835,
November 15, 2017) (AD 2017-23-02).
(c) Applicability
This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any
category, as identified in Boeing Alert Service Bulletin 737-
53A1358, Revision 1, dated February 26, 2021.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by an evaluation by the design approval
holder indicating that the fuselage crown skin panels are subject to
widespread fatigue damage. This AD was also prompted by a
determination that certain airplane configurations and inspection
locations need to be revised, and that additional airplanes are
subject to the unsafe condition. The FAA is issuing this AD to
address cracking in the fuselage crown skin panels. Multiple
adjacent cracks in the fuselage crown skin could link up and lead to
decompression or loss of structural integrity of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Actions for Group 43 Airplanes
For airplanes identified as Group 43 in Boeing Alert Service
Bulletin 737-53A1358, Revision 1, dated February 26, 2021, within
120 days after the effective date of this AD, inspect the airplane
and do all applicable on-condition actions using a method approved
in accordance with the procedures specified in paragraph (j) of this
AD
(h) Required Actions for Groups 1 Through 42 Airplanes
For airplanes identified as Groups 1 through 42 in Boeing Alert
Service Bulletin 737-53A1358, Revision 1, dated February 26, 2021,
except as specified by paragraph (i) of this AD: At the applicable
times specified in paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1358, Revision 1, dated February 26, 2021,
do all applicable actions identified as ``RC'' (required for
compliance) in, and in accordance with, the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1358, Revision
1, dated February 26, 2021. Actions identified as terminating action
in Boeing Alert Service Bulletin 737-53A1358, Revision 1, dated
February 26, 2021, terminate the applicable required actions of this
AD, provided the terminating action is done in accordance with the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1358, Revision 1, dated February 26, 2021.
(i) Exceptions to Service Information Specifications
(1) Where Boeing Alert Service Bulletin 737-53A1358, Revision 1,
dated February 26, 2021, uses the phrase ``the original issue date
of this service bulletin,'' this AD requires using ``December 20,
2017'' (the effective date of AD 2017-23-02).
(2) Where Boeing Alert Service Bulletin 737-53A1358, Revision 1,
dated February 26, 2021, specifies contacting Boeing for repair
instructions or for work instructions, this AD requires doing the
repair, or doing the work instructions and applicable on-condition
actions using a method approved in accordance with the procedures
specified in paragraph (j) of this AD.
(3) Part 7 of Boeing Alert Service Bulletin 737-53A1358,
Revision 1, dated February 26, 2021, specifies post-modification
airworthiness limitation inspections in compliance with 14 CFR
25.571(a)(3) at the modified locations to support compliance with 14
CFR 121.1109(c)(2) or 129.109(b)(2). Although Part 7 is identified
as RC, this AD does not require accomplishment of Part 7. As
airworthiness limitations, these inspections are required by
maintenance and operational rules. It is, therefore, unnecessary to
mandate them in this AD. Deviations from these inspections require
FAA approval, but do not require an alternative method of
compliance.
[[Page 47264]]
(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 Related Information. Information may be emailed
to: <a href="/cdn-cgi/l/email-protection#8ab3a7cbc4c7a7c6cbcbc9c5a7cbc7c5c9a7d8effbffeff9fef9caecebeba4ede5fc"><span class="__cf_email__" data-cfemail="7d44503c333050313c3c3e32503c30323e502f180c08180e090e3d1b1c1c531a120b">[email protected]</span></a>.
(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.
(4) AMOCs approved for AD 2017-23-02 are approved as AMOCs for
the corresponding provisions of Boeing Alert Service Bulletin 737-
53A1358, Revision 1, dated February 26, 2021, that are required by
paragraph (h) of this AD.
(5) Except as specified by paragraph (i)(2) of this AD: For
service information that contains steps that are labeled as Required
for Compliance (RC), the provisions of paragraphs (j)(5)(i) and (ii)
of this AD apply.
(i) The steps labeled as RC, including substeps under an RC step
and any figures identified in an RC step, must be done to comply
with the AD. If a step or substep is labeled ``RC Exempt,'' then the
RC requirement is removed from that step or substep. An AMOC is
required for any deviations to RC steps, including substeps and
identified figures.
(ii) Steps not labeled as RC may be deviated from using accepted
methods in accordance with the operator's maintenance or inspection
program without obtaining approval of an AMOC, provided the RC
steps, including substeps and identified figures, can still be done
as specified, and the airplane can be put back in an airworthy
condition.
(k) Related Information
(1) For more information about this AD, contact James Guo,
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch,
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5357; fax: 562-627-5210; email: <a href="/cdn-cgi/l/email-protection#b5dfd4d8d0c69bd2c0daf5d3d4d49bd2dac3"><span class="__cf_email__" data-cfemail="2248434f47510c45574d624443430c454d54">[email protected]</span></a>.
(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 <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. 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 August 7, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness
Division,Aircraft Certification Service.
[FR Doc. 2021-18068 Filed 8-23-21; 8:45 am]
BILLING CODE 4910-13-P
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