AD 2018-09-13

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by reports indicating additional cracking in the inspar upper skin at wing buttock line (WBL) 157 and in the skin at two holes common to the rear spar in the same area, and rear spar web cracks were also noted on both wings. Subsequent inspections revealed that the right rear spar upper chord was almost completely severed and the left rear spar upper chord was completely severed. Additional reports identified cracking in the main landing gear (MLG) beam forward support fitting. This AD requires the installation of standard-size fasteners for a certain configuration and inspections for any crack in certain locations of the rear spar. We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2018-09-13 The Boeing Company: Amendment 39-19270; Docket No. FAA- 2016-9523; Product Identifier 2016-NM-134-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective June 19, 2018. \n\n(b) Affected ADs \n\n\n\tThis AD affects AD 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014) (''AD 2014-12-13''); and AD 2015-21-08, Amendment 39- 18301 (80 FR 65921, October 28, 2015) (''AD 2015-21-08''). \n\n(c) Applicability \n\n\n\t(1) This AD applies to all The Boeing Company Model 737-100, - 200, -200C, -300, -400, and -500 series airplanes, certificated in anycategory. \n\t(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. \n\n(d) Subject \n\n\n\tAir Transport Association (ATA) of America Code 57, Wings. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of additional cracking in the inspar upper skin at wing buttock line 157 and in the skin at two holes common to the rear spar in the same area; rear spar web cracks were also noted on both wings. Subsequent inspections revealed that the right rear spar upper chord was almost completely severed and the left rear spar upper chord was completely severed. Additional reports identified cracking in the main landing gear (MLG) beam forward support fitting. We are issuing this AD to detect andcorrect cracking of the forward and aft support fittings for the MLG beam, and the rear spar upper chord and rear spar web in the area of rear spar station 224.14, which could grow and result in a fuel leak and possible fire. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Required Actions for Group 1 Airplanes (MLG Support Fittings and Rear Spar) \n\n\n\tFor airplanes identified as Group 1 in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the applicable time specified in table 1 of paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, do applicable inspections and corrective actions using a method approved in accordance with the procedures specified in paragraph (l) of this AD. \n\n(h) Required Actions for Groups 2-7 Airplanes (MLG Support Fittings and Rear Spar) \n\n\n\tFor airplanes identified as Groups 2-7 in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the applicable time specified in table 2 through table 9 of paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, except as required by paragraph (j)(3) of this AD, do high frequency eddy current (HFEC) open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web at the 12 fastener holes (locations 1-12); or HFEC open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web, and an HFEC surface inspection for any cracking in the rear spar upper chord and rear spar upper web; as applicable; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, except as provided by paragraph (h)(1) of this AD, and except as required by paragraphs (h)(2) and (j)(1) of this AD. Do all applicable related investigative and corrective actions before further flight. Thereafter, repeat the HFEC inspection at the applicable time specified in table 2 through table 9 of paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. \n\t(1) Options provided in Boeing Alert Service Bulletin 737- 57A1318, Revision 1, dated July 22, 2016, for accomplishing the inspection are acceptable for the corresponding requirements in the introductory text of paragraph (h) of this AD, provided that the inspections are done at the applicable times in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. \n\t(2) For Group 7, Configuration 1, airplanes identified in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: Install standard-size fasteners in accordance with figures 29 and 30 of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. If the existing fastener holes exceed the permitted hole diameter, repair before further flight using a method approved in accordance with the procedures specified in paragraph (l) of this AD. \n\n(i) Eddy Current Inspection (Inspar Upper Skin) \n\n\n\tFor airplanes identified in Boeing Alert Service Bulletin 737- 57A1328, dated July 22, 2016: At the applicable time specified in table 1 and table 2 of paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, except as required by paragraph (j)(2) of this AD, do an eddy current inspection of the left and right wings for any cracking in the inspar upper skin, and at the repair parts if installed, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, except as required by paragraph (j)(1) of this AD. Do all related investigative and corrective actions before further flight. Thereafter, repeat the eddy current inspection at the applicable time specified in table 1 and table 2 of paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016. \n\n(j) Exceptions to the Service Information \n\n\n\t(1) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016; or Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016; specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD. \n\t(2) Where Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, specifies a compliance time ''after the Original Issue date of this service bulletin,'' this AD requires compliance within the specified compliance time after the effective date of this AD. \n\t(3) Where Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, specifies a compliance time ''after the Revision 1 date of this service bulletin, whichever occurs later,'' this AD requires compliance within the specified compliance time after the effective date of this AD. \n\n(k) Terminating Action \n\n\n\t(1) Accomplishing the initial inspections and applicable related investigative and corrective actions required by paragraphs (g), (h), and (i) of this AD, as applicable, terminates all requirements of AD 2015-21-08. \n\t(2) Accomplishing the initial inspections and applicable related investigative and corrective actions required by paragraphs (g) and (h) of this AD, as applicable, terminates all requirements of AD 2014-12-13. \n\n(l) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Los Angeles ACO Branch, FAA, has the authority to approve AMOCs \n\n((Page 22354)) \n\nfor this AD, if requested using the procedures found in14 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) of this AD. Information may be emailed to: 9-ANM-LAACO-AMOC-Requests@faa.gov. \n\t(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. \n\t(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, 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. \n\t(4) AMOCs approved previously for AD 2014-12-13 are approved as AMOCs for the corresponding provisions of paragraphs (g) and (h) of this AD. \n\t(5) Except as required by paragraph (j)(1) of this AD: For service information that contains steps that are labeled as Required for Compliance (RC), the provisions of paragraphs (l)(5)(i) and (l)(5)(ii) of this AD apply. \n\t(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 sub-step is labeled ''RC Exempt,'' then the RC requirement is removed from that step or sub-step. An AMOC is required for any deviations to RC steps, including substeps and identified figures. \n\t(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. \n\n(m) Related Information \n\n\n\tFor more information about this AD, contact Payman Soltani, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5313; fax: 562-627-5210; email: payman.soltani@faa.gov. \n\n(n) Material Incorporated by Reference \n\n\n\t(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. \n\t(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. \n\t(i) Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. \n\t(ii) Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016. \n\t(3) For Boeing 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; telephone 562-797-1717; internet https://www.myboeingfleet.com. \n\t(4) 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. \n\t(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, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on January 5, 2017 (82 FR 1254). The NPRM was prompted by reports of cracking in locations outside the inspection area identified in AD 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014) (''AD 2014-12-13''), in the inspar upper skin at WBL 157 and in the skin at two holes common to the rear spar in the same area, and in the rear spar web on both wings. Subsequent inspections revealed that the right rear spar upper chord was almost completely severed and the left rear spar upper chord was completely severed. Operators also reported cracking in the MLG beam forward support fitting. \n\tWe subsequently issued a supplemental notice of proposed rulemaking (SNPRM) which was published in the FederalRegister on August 11, 2017 (83 FR 37549) (''the first SNPRM''). The first SNPRM proposed to require expanding the inspection area, add applicable related investigative and corrective actions, and to terminate (rather than supersede) the requirements of AD 2014-12-13 after accomplishment of the initial inspections. \n\tWe issued a second SNPRM which was published in the Federal Register on January 17, 2018 (83 FR 2378) (''the 2018 SNPRM''). The 2018 SNPRM proposed to require the installation of standard-size fasteners for a certain \n\n((Page 22352)) \n\nconfiguration. We are issuing this AD to address cracking of the forward and aft support fittings for the main landing gear beam, and the rear spar upper chord and rear spar web in the area of rear spar station 224.14, which could grow and result in a fuel leak and possible fire. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this final rule. We have considered the comment received. Boeing supportedthe 2018 SNPRM. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting this final rule as proposed, except for minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the 2018 SNPRM for addressing the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the 2018 SNPRM. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. This service information describes procedures for repetitive high frequency eddy current (HFEC) open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web at the 12 fastener holes (locations 1-12). This service information also describes procedures for optional HFEC open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web, and HFEC surface inspections for any cracking in the rear spar upper chord and rear spar upper web, as applicable. This service information also describes procedures for related investigative and corrective actions. \n\tWe also reviewed Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016. This service information describes procedures for repetitive eddy current inspections of the left and right wing for any cracking in the inspar upper skin and at the repair parts if applicable, and related investigative and corrective actions. \n\tThis 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. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 471 airplanes of U.S. registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- HFEC open hole inspections....... 82 work-hours x $85 $0 $6,970 per $3,282,870 per \n\tper hour = $6,970 inspection cycle. inspection cycle. \n\tper inspection \n\tcycle. Eddy current inspection.......... 14 work-hours x $85 $0 $1,190 per $560,490 per \n\tper hour = $1,190 inspection cycle. inspection cycle. \n\tper inspection \n\tcycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\n\n\tEstimated Costs for Optional Actions ---------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product ---------------------------------------------------------------------------------------------------------------- Inspection.............................. Up to 41 work-hours x $85 $0 Up to $1,641,435 per \n\tper hour = $3,485 per inspection cycle. \n\tinspection cycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that will enable us to provide cost estimates for the on-condition actions specified in this AD. \n\nAuthority for This Rulemaking \n\n\n\tTitle 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. \n\tWe 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. \n\tThis 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. \n\nRegulatory Findings \n\n\n\tThis 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) Will not have a significant economic impact, positive or negative, on a substantial number of small entities \n\n((Page 22353)) \n\nunder the criteria of the Regulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.