[Federal Register Volume 82, Number 193 (Friday, October 6, 2017)]
[Proposed Rules]
[Pages 46725-46727]
[FR Doc No: 2017-21225]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0903; Product Identifier 2017-NM-074-AD]
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: We propose to adopt a new airworthiness directive (AD) for
certain The Boeing Company Model 737-300 and -500 series airplanes.
This proposed AD was prompted by a report indicating that fatigue
cracks were found in the lower wing skin of an airplane with winglets
installed. This proposed AD would require repetitive inspections for
cracking of the lower wing skin, and repair if necessary. We are
proposing this AD to address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by November 20,
2017.

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 http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     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 Aviation
Partners Boeing, 2811 South 102nd Street, Suite 200, Seattle, WA 98168;
phone: 1-206-830-7699; fax: 1-206-767-3355; email:
<EMAIL_ADDRESS>Internet: http://www.aviationpartnersboeing.com. You may view this service information
at the FAA, Transport Standards Branch, 1601 Lind Avenue SW., Renton,
WA. For information on the availability of this material at the FAA,
call<PHONE_NUMBER>.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-
0903; or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this NPRM, the regulatory evaluation, any comments received,
and other information. The street address for the Docket Office (phone:
800-647-5527) is in the ADDRESSES section. Comments will be available
in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:  Lu Lu, Aerospace Engineer, Airframe
Section, FAA, Seattle ACO Branch, 1601 Lind Avenue SW., Renton, WA
98057-3356; phone:<PHONE_NUMBER>; fax:<PHONE_NUMBER>; email:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include ``Docket No. FAA-2017-0903;
Product Identifier 2017-NM-074-AD'' at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this NPRM.

Discussion

    We have received a report indicating that fatigue cracks were found
in the lower wing skin at the farthest outboard fastener of stringer L-
5 between wing station (WSTA) 479 and WSTA 505 on a Model 737-300
airplane with Aviation Partners Boeing blended winglet kit installed
per Supplemental Type Certificate (STC) ST01219SE. If not corrected,
fatigue cracking of the lower wing skin common to the runout of
stringer L-5 on Boeing Model 737-300 and 737-500 airplanes with
winglets installed could grow and result in loss of the structural
integrity of the wing, and reduced, or complete loss of,
controllability of the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed Aviation Partners Boeing Service Bulletin AP737C-57-
002, dated April 5, 2017. The service information describes procedures
for repetitive inspections for cracking of the lower wing skin, and on-
condition actions. 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.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require accomplishment of the actions
specified in the service information described previously, except as
discussed under ``Differences Between this Proposed AD and the Service
Information.''

Differences Between This Proposed AD and the Service Information

    Aviation Partners Boeing Service Bulletin AP737C-57-002, dated
April 5, 2017, specifies to contact the manufacturer for certain
instructions, but this proposed AD would require using repair methods,
modification deviations, and alteration deviations in one of the
following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) whom we have
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 93 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Cost on U.S.
               Action                     Labor cost        Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Repetitive inspection...............  1 work-hour x $85               $0  $85 per inspection  Up to $7,905 per
                                       per hour = $85                      cycle.              inspection cycle.
                                       per inspection
                                       cycle.
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    We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions 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.
    We are 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.
    This proposed AD is issued in accordance with authority delegated
by the Executive Director, Aircraft Certification Service, as
authorized by FAA Order 8000.51C. In accordance with that order,
issuance of ADs is normally a function of the Compliance and
Airworthiness Division, but during this transition period, the
Executive Director has delegated the authority to issue ADs applicable
to transport category airplanes to the Director of the System Oversight
Division.

Regulatory Findings

    We 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) Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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 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 (AD):

The Boeing Company: Docket No. FAA-2017-0903; Product Identifier
2017-NM-074-AD.

(a) Comments Due Date

    We must receive comments by November 20, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-300 and -500
series airplanes, certificated in any category, with blended winglet
kits installed in accordance with Supplemental Type Certificate
(STC) ST01219SE.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report indicating that fatigue cracks
were found in the lower wing skin at stringer L-5 of a Boeing Model
737-300 airplane with winglets installed. We are issuing this AD to
detect and correct fatigue cracking of the lower wing skin common to
the runout of stringer L-5, which could grow and result in loss of
structural integrity of the wing, and consequent reduced, or
complete loss of, controllability of the airplane.

(f) Compliance

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

(g) Repetitive Inspection

    Within 18 months after the effective date of this AD: Do a
detailed inspection for cracking of the lower wing skin external
surface at the stringer L-5 location on the left and right wings, in
accordance with the Accomplishment Instructions of Aviation Partners
Boeing Service Bulletin AP737C-57-002, dated April 5, 2017. Repeat
the inspection thereafter at intervals not to exceed 6,000 flight
cycles or 9,000 flight hours, whichever occurs first.

(h) Repair

    If any crack is found during any inspection required by
paragraph (g) of this AD, repair before further flight using a
method approved in accordance with the procedures specified in
paragraph (i) of this AD. Although Aviation Partners Boeing Service
Bulletin AP737C-57-002, dated April 5, 2017, specifies to contact
Boeing for repair instructions, and specifies that action as ``RC''
(Required for Compliance), this AD requires repair as specified in
this paragraph.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 (j)(1) 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 Commercial Airplanes Organization
Designation Authorization (ODA) that has been authorized by the
Manager, Seattle ACO Branch, 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) Except as required by paragraph (h) of this AD: For service
information that contains steps that are labeled as RC, the

provisions of paragraphs (i)(4)(i) and (i)(4)(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.

(j) Related Information

    (1) For more information about this AD, contact Lu Lu, Aerospace
Engineer, Airframe Section, FAA, Seattle ACO Branch, 1601 Lind
Avenue SW., Renton, WA 98057-3356; phone:<PHONE_NUMBER>; fax: 425-
917-6590; email<EMAIL_ADDRESS>    (2) For service information identified in this AD, contact
Aviation Partners Boeing, 2811 South 102nd Street, Suite 200,
Seattle, WA 98168; phone: 1-206-830-7699; fax: 1-206-767-3355;
email<EMAIL_ADDRESS>Internet: http://www.aviationpartnersboeing.com. You may view this referenced service
information at the FAA, Transport Standards Branch, 1601 Lind Avenue
SW., Renton, WA. For information on the availability of this
material at the FAA, call<PHONE_NUMBER>.

    Issued in Renton, Washington, on September 25, 2017.
Dionne Palermo,
Acting Director, System Oversight Division, Aircraft Certification
Service.
[FR Doc. 2017-21225 Filed 10-5-17; 8:45 am]
 BILLING CODE 4910-13-P