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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
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 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:
                    ( print page 46726) Estimated Costs
Action
Labor cost
Parts cost
Cost per product
Cost on U.S. operatorsRepetitive inspection
1 work-hour × $85 per hour = $85 per inspection cycle
$0
$85 per inspection cycle
Up to $7,905 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
 1.The authority citation for part 39 continues to read as follows: Authority:
                    49 U.S.C. 106(g), 40113, 44701. § 39.13
 2.The FAA amends § 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 
                        ( print 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