[Federal Register Volume 85, Number 245 (Monday, December 21, 2020)]
[Rules and Regulations]
[Pages 82896-82899]
[FR Doc No: 2020-28029]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0689; Product Identifier 2020-NM-060-AD; Amendment
39-21359; AD 2020-26-04]
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 superseding Airworthiness Directive (AD) 2013-18-
08, which applied to certain The Boeing Company Model 737-200, -200C, -
300, -400, and -500 series airplanes. AD 2013-18-08 required repetitive
inspections for cracking of certain skin panels of the fuselage, and of
the fuselage skin along certain chem-milled lines, and corrective
actions if necessary. AD 2013-18-08 also included a terminating action
for the repetitive inspections of certain areas. This AD retains those
actions, expands the nondestructive inspection (NDI) area, and adds
airplanes to the applicability. This AD was prompted by reports of
additional cracking in certain horizontal and vertical chem-milled step
locations outside of those identified in AD 2013-18-08. The FAA is
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective January 25, 2021.
    The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 25,
2021.

ADDRESSES: 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<PHONE_NUMBER>; internet https://www.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, call<PHONE_NUMBER>. It is also available on
the internet at https://www.regulations.gov by searching for and
locating Docket No. FAA-2020-0689.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0689; 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.

FOR FURTHER INFORMATION CONTACT: James Guo, Aerospace Engineer,
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount
Boulevard, Lakewood, CA 90712-4137; phone:<PHONE_NUMBER>; fax: 562-627-
5210; email<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2013-18-08, Amendment 39-17581 (78 FR
60660, October 2, 2013) (AD 2013-18-08). AD 2013-18-08 applied to
certain The Boeing Company Model 737-200, -200C, -300, -400, and -500
series airplanes. The NPRM published in the Federal Register on August
17, 2020 (85 FR 49978). The NPRM was prompted by reports of additional
cracking in certain horizontal and vertical chem-milled step locations
outside of those identified in AD 2013-18-08. The NPRM proposed to
continue to require repetitive inspections for cracking of the fuselage
skin along certain chem-milled lines and applicable on-condition
actions, and to expand the NDI area. The NPRM also proposed to continue
to provide terminating action for repetitive inspections of certain
modified or repaired areas. The NPRM also proposed to add airplanes to
the applicability. The FAA is issuing this AD to address fatigue
cracking of the skin panels, which could result in sudden fracture and
failure of the skin panels of the fuselage, and consequent rapid
decompression of the airplane.

Comments

    The FAA gave the public the opportunity to participate in
developing this AD. The following presents the comments received on the
NPRM and the FAA's response to each comment. An individual had no
objection to the NPRM.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental
Type Certificate (STC) ST01219SE does not

affect compliance with the proposed actions.
    The FAA agrees with the commenter. Paragraph (c) of the proposed AD
has been redesignated as paragraph (c)(1) of this AD, and paragraph
(c)(2) has been added to this AD to state that installation of STC
ST01219SE does not affect the ability to accomplish the actions
required by this AD. Therefore, for airplanes on which STC ST01219SE is
installed, a ``change in product'' alternative method of compliance
(AMOC) approval request is not necessary to comply with the requirement
of 14 CFR 39.17.

Request To Revise Certain Language in the Preamble

    Boeing asked that the FAA change the language under the section
titled ``Actions Since AD 2013-18-08 was Issued.'' Boeing asked that
the FAA refer to the ``NDI inspection'' instead of the ``repetitive
inspection.''
    Boeing also asked that the FAA change the language under the
section titled ``Proposed AD Requirements.'' Boeing asked that the FAA
refer to the expanded area for the existing NDI inspection instead of
referring to the expanded area for the existing inspection.
    Boeing requested these changes because Boeing Alert Service
Bulletin 737-53A1346, dated March 27, 2020, expands only the initial
and repetitive NDI areas and not the detailed visual inspection area.
    The FAA acknowledges that the expanded inspections are only to the
NDI area. Those sections of the preamble do not reappear in the final
rule; however, the FAA clarified that the NDI area is expanded in the
Summary and Discussion sections.

Conclusion

    The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this AD with the changes described previously, and
minor editorial changes. The FAA has determined that these minor
changes:
     Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Service Bulletin 737-53A1346, dated
March 27, 2020. This service information describes procedures for
repetitive detailed and non-destructive tests (NDTs) (including
external medium frequency eddy current (MFEC), external magneto optical
imaging (MOI), external c-scan, external sliding probe, external high
frequency eddy current (HFEC), external low frequency eddy current
(LFEC), internal ultrasonic phased array (UTPA), or internal
ultrasonic); inspections for cracking of the fuselage skin along all
horizontal and vertical chem-milled locations with a history of
cracking between stations (STAs) 259.5 and 1016; and applicable on-
condition actions. On-condition actions include repair; LFEC
inspections of certain repairs for cracking; detailed inspections of
certain repairs for cracking and loose, missing, or damaged fasteners;
replacement of loose, missing, or damaged fasteners; and preventative
modifications. 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.

Costs of Compliance

    The FAA estimates that this AD affects 141 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:

                  Estimated Costs for Required Actions
------------------------------------------------------------------------
                                                             Cost per
        Action            Labor cost       Parts cost        product
------------------------------------------------------------------------
Inspections..........  Up to 165                     $0  Up to
                        work[dash]hours                   $1,977,525 per
                        x $85 per hour                    inspection
                        = Up to $14,025                   cycle.
                        per inspection
                        cycle.
------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary
corrective actions required based on the results of the inspections.
The FAA has no way of determining the number of aircraft that might
need these corrective actions:

                 Estimated Costs of On-Condition Actions
------------------------------------------------------------------------
           Labor cost                 Parts cost       Cost per product
------------------------------------------------------------------------
Up to 185 work-hours x $85 per    $*................  Up to $15,725.
 hour = Up to $15,725.
------------------------------------------------------------------------
* The FAA has received no definitive data that enables providing parts
  costs for the on-condition actions specified in this 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 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.

Adoption of 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:
0
a. Removing Airworthiness Directive (AD) 2013-18-08, Amendment 39-17581
(78 FR 60660, October 2, 2013), and
0
b. Adding the following new AD:

2020-26-04 The Boeing Company: Amendment 39-21359; Docket No. FAA-
2020-0689; Product Identifier 2020-NM-060-AD.

(a) Effective Date

    This AD is effective January 25, 2021.

(b) Affected ADs

    This AD replaces AD 2013-18-08, Amendment 39-17581 (78 FR 60660,
October 2, 2013) (AD 2013-18-08).

(c) Applicability

    (1) 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-
53A1346, dated March 27, 2020.
    (2) Installation of Supplemental Type Certificate (STC)
ST01219SE does not affect the ability to accomplish the actions
required by this AD. Therefore, for airplanes on which STC ST01219SE
is installed, a ``change in product'' alternative method of
compliance (AMOC) approval request is not necessary to comply with
the requirements of 14 CFR 39.17.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of additional cracking in the
horizontal and vertical chem-milled step locations outside of those
identified in AD 2013-18-08. The FAA is issuing this AD to address
fatigue cracking of the skin panels, which could result in sudden
fracture and failure of the skin panels of the fuselage, and
consequent rapid decompression of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified,
unless already done.

(g) Required Actions for Group 1 Through 25 Airplanes

    For airplanes identified as Group 1 through 25 in Boeing Alert
Service Bulletin 737-53A1346, dated March 27, 2020, except as
specified in paragraph (h) of this AD: At the applicable times
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service
Bulletin 737-53A1346, dated March 27, 2020, do all applicable
actions identified as ``RC'' (required for compliance) in, and in
accordance with, the Accomplishment Instructions of Boeing Alert
Service Bulletin 737-53A1346, dated March 27, 2020. Actions
identified as terminating action in Boeing Alert Service Bulletin
737-53A1346, dated March 27, 2020, 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 737-53A1346, dated March 27, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1346, dated March
27, 2020, uses the phrase ``the original issue date of this service
bulletin,'' this AD requires using ``the effective date of this
AD.''
    (2) Where Boeing Alert Service Bulletin 737-53A1346, dated March
27, 2020, specifies contacting Boeing for repair instructions, this
AD requires doing the repair before further flight using a method
approved in accordance with the procedures specified in paragraph
(j) of this AD.

(i) Required Actions for Group 26 Airplanes

    For airplanes identified as Group 26 in Alert Service Bulletin
737-53A1346, dated March 27, 2020: Within 120 days after the
effective date of this AD, inspect the fuselage skin along certain
chem-milled lines for cracks, using a method approved in accordance
with the procedures specified in paragraph (j) of this AD.

(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 local Flight Standards
District 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) of this AD. Information may
be emailed to<EMAIL_ADDRESS>    (2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district 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 previously for AD 2013-18-08 are approved as
AMOCs for the corresponding provisions of Boeing Alert Service
Bulletin 737-53A1346, dated March 27, 2020, which are required by
paragraph (g) of this AD.
    (5) 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

    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:<PHONE_NUMBER>;
fax:<PHONE_NUMBER>; email<EMAIL_ADDRESS>
(l) 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 Service Bulletin 737-53A1346, dated March 27,
2020.
    (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<PHONE_NUMBER>; internet https://www.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<PHONE_NUMBER>.

    (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<EMAIL_ADDRESS>or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on December 7, 2020.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2020-28029 Filed 12-18-20; 8:45 am]
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