
[Federal Register Volume 82, Number 193 (Friday, October 6, 2017)]
[Proposed Rules]
[Pages 46725-46727]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-21225]



[[Page 46725]]

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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: 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 Aviation 
Partners Boeing, 2811 South 102nd Street, Suite 200, Seattle, WA 98168; 
phone: 1-206-830-7699; fax: 1-206-767-3355; email: 
leng@aviationpartners.com; 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 425-227-1221.

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: 425-917-6478; fax: 425-917-6590; email: 
lu.lu@faa.gov.

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:

[[Page 46726]]



                                                 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.
----------------------------------------------------------------------------------------------------------------

    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: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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

[[Page 46727]]

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: 425-917-6478; fax: 425-
917-6590; email: lu.lu@faa.gov.
    (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: leng@aviationpartners.com; 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 425-227-1221.

    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


