Airworthiness Directives; The Boeing Company Airplanes

Published date01 April 2019
Citation84 FR 12143
Record Number2019-06031
SectionProposed rules
CourtFederal Aviation Administration
Federal Register, Volume 84 Issue 62 (Monday, April 1, 2019)
[Federal Register Volume 84, Number 62 (Monday, April 1, 2019)]
                [Proposed Rules]
                [Pages 12143-12146]
                From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
                [FR Doc No: 2019-06031]
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                DEPARTMENT OF TRANSPORTATION
                Federal Aviation Administration
                14 CFR Part 39
                [Docket No. FAA-2019-0187; Product Identifier 2018-NM-172-AD]
                RIN 2120-AA64
                Airworthiness Directives; The Boeing Company Airplanes
                AGENCY: Federal Aviation Administration (FAA), DOT.
                ACTION: Notice of proposed rulemaking (NPRM).
                -----------------------------------------------------------------------
                SUMMARY: We propose to supersede Airworthiness Directive (AD) 2005-20-
                01, which applies to all The Boeing Company Model 737-100, -200, -200C,
                -300, -400, and -500 series airplanes. AD 2005-20-01 requires
                repetitive inspections of the vertical stiffeners at left buttock line
                (LBL) and right buttock line (RBL) 6.15 for cracks; and replacement of
                both stiffeners with new, improved stiffeners if any stiffener is found
                cracked. Since we issued AD
                [[Page 12144]]
                2005-20-01, we have received reports of cracks found in the left and
                right side keel beam upper chords when replacing vertical stiffeners.
                In addition, we have determined that the replacement stiffener
                installation degraded the fault current bonding path and could
                introduce an ignition source in the fuel tank in the event of an
                electrical hot short or a lightning strike. This proposed AD would
                require, depending on airplane configuration, replacing the vertical
                stiffeners at LBL and RBL 6.15 on the rear spar of the wing center
                section, installing angle and bonding jumpers, installing brackets,
                applying sealant, and applying paint. We are proposing this AD to
                address the unsafe condition on these products.
                DATES: We must receive comments on this proposed AD by May 16, 2019.
                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 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 https://www.myboeingfleet.com. You may
                view this service information at the FAA, Transport Standards 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 on the internet at http://www.regulations.gov by searching
                for and locating Docket No. FAA-2019-0187.
                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-2019-
                0187; 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, the regulatory evaluation, any comments received, and other
                information. The street address for Docket Operations (phone: 800-647-
                5527) is in the ADDRESSES section. Comments will be available in the AD
                docket shortly after receipt.
                FOR FURTHER INFORMATION CONTACT: Galib Abumeri, Aerospace Engineer,
                Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount
                Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5324; fax: 562-627-
                5210; email: [email protected].
                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-2019-0187;
                Product Identifier 2018-NM-172-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 proposed AD.
                Discussion
                 We issued AD 2005-20-01, Amendment 39-14294 (70 FR 56358, September
                27, 2005) (``AD 2005-20-01''), for all The Boeing Company Model 737-
                100, -200, -200C, -300, -400, and -500 series airplanes. AD 2005-20-01
                requires repetitive inspections of the vertical stiffeners at LBL and
                RBL 6.15 for cracks; and replacement of both stiffeners with new,
                improved stiffeners if any stiffener is found cracked. AD 2005-20-01
                also allows replacement of both stiffeners at LBL and RBL 6.15 with
                new, improved stiffeners, which terminates the repetitive inspections.
                AD 2005-20-01 resulted from reports of cracks in the aft vertical
                stiffeners at LBL and RBL 6.15 on the rear spar of the wing center
                section. We issued AD 2005-20-01 to address cracks in the vertical
                stiffeners at LBL and RBL 6.15, which could result in damage to the
                keel beam structure and consequently reduce the capability of the
                airplane to sustain flight loads.
                Actions Since AD 2005-20-01 Was Issued
                 Since we issued AD 2005-20-01, Boeing discovered that the
                replacement stiffener installation had degraded fault current bonding
                because the existing rivets (which provide an inherent bond path for
                fault currents and ground returns) had been replaced with non-
                conductive finish K-code fasteners in transition fit holes. The
                replacement fasteners are not adequate in maintaining required fault
                current bonding path and could introduce an ignition source in the fuel
                tank in the event of an electrical hot short or a lightning strike.
                 In addition to the above described electrical bonding issues, we
                received a report of cracks in the left side and right side keel beam
                upper chords when the aft vertical stiffeners were replaced. Boeing
                determined that the actual stresses on aft vertical stiffeners at LBL
                and RBL 6.15 exceed those used to design the structure and can cause
                fatigue cracks in the stiffeners. If the aft vertical stiffeners have
                cracks or are severed, the fatigue damage may extend into the adjacent
                keel beam structure and could reduce the limit load capability of the
                keel beam structure. Boeing has determined the inspections described in
                Boeing Alert Service Bulletin 737-57A1269, dated December 4, 2003; and
                Revision 1, dated September 16, 2004; do not provide sufficient
                inspection intervals for timely crack detection in the aft vertical
                stiffeners. AD 2005-20-01 requires the actions specified in Boeing
                Alert Service Bulletin 737-57A1269, dated December 4, 2003; and
                Revision 1, dated September 16, 2004. As a result, Boeing issued Alert
                Service Bulletin 737-57A1339 RB, dated April 16, 2018, which describes
                procedures for inspecting the vertical stiffeners and keel beam upper
                chord structures. AD 2018-10-12, Amendment 39-19288 (83 FR 23775, May
                23, 2018) (``AD 2018-10-12'') requires the actions specified in Boeing
                Alert Service Bulletin 737-57A1339 RB, dated April 16, 2018. After we
                issued AD 2018-10-12, Boeing issued Boeing Alert Service Bulletin 737-
                57A1269, Revision 2, dated October 11, 2018, which provides procedures
                for replacing the vertical stiffeners with new, improved stiffeners.
                 Accomplishment of the vertical stiffener replacements at LBL and
                RBL 6.15, described in Boeing Alert Service Bulletin 737-57A1269,
                Revision 2, dated October 11, 2018, as specified in paragraph (g) of
                this proposed AD, eliminates the need to do the stiffener inspection
                described in Boeing Alert Service Bulletin 737-57A1339 RB, dated April
                16, 2018.
                Related Service Information Under 1 CFR Part 51
                 We reviewed Boeing Alert Service Bulletin 737-57A1269, Revision 2,
                [[Page 12145]]
                dated October 11, 2018. This service information describes procedures
                for replacing the vertical stiffeners at LBL and RBL 6.15 on the wing
                center section rear spar with new, improved stiffeners, installing
                angle and bonding jumpers, installing brackets, applying sealant, and
                applying paint.
                 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 retain none of the requirements of AD 2005-
                20-01. This proposed AD would require accomplishing the actions
                specified in the service information described previously except as
                discussed under ``Differences Between this Proposed AD and the Service
                Information,'' and except for any differences identified as exceptions
                in the regulatory text of this proposed AD. For certain airplanes,
                replacing the vertical stiffeners with new, improved stiffeners, would
                terminate the need for the repetitive inspections required by AD 2018-
                10-12. For information on the procedures and compliance times, see this
                service information at http://www.regulations.gov by searching for and
                locating Docket No. FAA-2019-0187.
                Differences Between This Proposed AD and the Service Information
                 Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated
                October 11, 2018, specifies, for certain airplanes, to do a concurrent
                action consisting of a final one-time surface high frequency eddy
                current inspection of the keel beam upper chord and general visual
                inspection of the angle at LBL 6.50 and RBL 6.50, and all related
                applicable actions, as specified in Boeing Alert Requirements Bulletin
                737-57A1339 RB, dated April 16, 2018. We have determined that action is
                already mandated by AD 2018-10-12. All requirements of AD 2018-10-12
                remain in effect.
                Costs of Compliance
                 We estimate that this proposed AD affects 171 airplanes of U.S.
                registry. We estimate the following costs to comply with this proposed
                AD:
                 Estimated Costs
                ----------------------------------------------------------------------------------------------------------------
                 Parts
                 Action Labor cost cost Cost per product Cost on U.S. operators
                ----------------------------------------------------------------------------------------------------------------
                Stiffener replacement, angle Up to 257 work- $14,730 Up to $36,575............ Up to $6,254,325.
                 and bonding jumper hours x $85 per
                 installation, bracket hour = $21,845.
                 installation, and sealant
                 and paint application.
                ----------------------------------------------------------------------------------------------------------------
                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 and associated appliances to the
                Director of the System Oversight Division.
                Regulatory Findings
                 We have 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) 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 removing Airworthiness Directive (AD)
                2005-20-01, Amendment 39-14294 (70 FR 56358, September 27, 2005), and
                adding the following new AD:
                The Boeing Company: Docket No. FAA-2019-0187; Product Identifier
                2018-NM-172-AD.
                (a) Comments Due Date
                 The FAA must receive comments on this AD action by May 16, 2019.
                (b) Affected ADs
                 This AD replaces AD 2005-20-01, Amendment 39-14294 (70 FR 56358,
                [[Page 12146]]
                September 27, 2005) (``AD 2005-20-01''). This AD terminates certain
                requirements of AD 2018-10-12, Amendment 39-19288 (83 FR 23775, May
                23, 2018) (``AD 2018-10-12'').
                (c) Applicability
                 This AD applies to all The Boeing Company Model 737-100, -200, -
                200C, -300, -400, and -500 series airplanes, certificated in any
                category.
                (d) Subject
                 Air Transport Association (ATA) of America Code 57, Wings.
                (e) Unsafe Condition
                 This AD was prompted by reports of cracks in the aft vertical
                stiffeners at left buttock line (LBL) and right buttock line (RBL)
                6.15 on the rear spar of the wing center section and of cracks found
                in the left and right side keel upper chords when replacing vertical
                stiffeners. This AD was also prompted by possible degradation of the
                fault current bonding path due to the replacement vertical stiffener
                installation. We are issuing this AD to address cracks in vertical
                stiffeners at LBL and RBL 6.15, which could result in damage to the
                keel beam structure and consequently reduce the capability of the
                airplane to sustain flight loads. We are also issuing this AD to
                address a potential ignition source in the fuel tank due to
                insufficient bonding, which could lead to a fuel tank explosion and
                subsequent loss of the airplane.
                (f) Compliance
                 Comply with this AD within the compliance times specified,
                unless already done.
                (g) Required Actions for Group 1 and 3 Through 8 Airplanes
                 For airplanes identified as Group 1 and 3 through 8 in Boeing
                Alert Service Bulletin 737-57A1269, Revision 2, dated October 11,
                2018: Except as specified by paragraph (j) of this AD, at the
                applicable times specified in paragraph 1.E., ``Compliance,'' of
                Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October
                11, 2018, do all applicable actions, identified in, and in
                accordance with, the Accomplishment Instructions of Boeing Alert
                Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018.
                Depending on the airplane configuration, applicable actions include
                replacing the vertical stiffeners at LBL and RBL 6.15 on the rear
                spar of the wing center section, installing angle and bonding
                jumpers, installing brackets, applying sealant, and applying paint.
                (h) Required Actions for Group 2 Airplanes
                 For airplanes identified as Group 2 in Boeing Alert Service
                Bulletin 737-57A1269, Revision 2, dated October 11, 2018: Within 120
                days after the effective date of this AD, do actions to correct the
                unsafe condition, using a method approved in accordance with the
                procedures specified in paragraph (l) of this AD.
                (i) Terminating Action for Repetitive Inspections of Aft Vertical
                Stiffener Required by AD 2018-10-12
                 Accomplishment of the stiffener replacement required by
                paragraph (g) of this AD terminates only the repetitive inspections
                of the aft vertical stiffeners required by paragraph (h) of AD 2018-
                10-12 for that airplane only. All other requirements of paragraph
                (h) of AD 2018-10-12 remain in effect.
                (j) Exceptions to Service Information Specifications
                 (1) For purposes of determining compliance with the requirements
                of this AD: Where Boeing Alert Service Bulletin 737-57A1269,
                Revision 2, dated October 11, 2018, uses the phrase ``the Revision 2
                date of this service bulletin,'' this AD requires using ``the
                effective date of this AD.''
                 (2) Where Boeing Alert Service Bulletin 737-57A1269, Revision 2,
                dated October 11, 2018, 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 (l) of this AD.
                (k) Credit for Previous Actions
                 This paragraph provides credit only for the stiffener
                replacement required by paragraph (g) of this AD, if those actions
                were performed before the effective date of this AD using the
                service information identified in paragraph (k)(1) or (k)(2) of this
                AD.
                 (1) Boeing Alert Service Bulletin 737-57A1269, dated December 4,
                2003, which is not incorporated by reference in this AD.
                 (2) Boeing Alert Service Bulletin 737-57A1269, Revision 1, dated
                September 16, 2004, which was incorporated by reference in AD 2005-
                20-01.
                (l) 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 (m)(1) of this AD. Information
                may be emailed to: [email protected].
                 (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, 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.
                (m) Related Information
                 (1) For more information about this AD, contact Galib Abumeri,
                Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch,
                3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
                5324; fax: 562-627-5210; email: [email protected].
                 (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 https://www.myboeingfleet.com. You may view this referenced service
                information at the FAA, Transport Standards Branch, 2200 South 216th
                St., Des Moines, WA. For information on the availability of this
                material at the FAA, call 206-231-3195.
                 Issued in Des Moines, Washington, on March 22, 2019.
                Michael Kaszycki,
                Acting Director, System Oversight Division, Aircraft Certification
                Service.
                [FR Doc. 2019-06031 Filed 3-29-19; 8:45 am]
                BILLING CODE 4910-13-P
                

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