AD 2018-21-08

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, -500 series airplanes. This AD was prompted by the results of a fleet survey that revealed cracking in the bulkhead frame web at a certain body station. This AD requires repetitive inspections of the bulkhead frame web at a certain station, and applicable on-condition actions. 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\n2018-21-08 The Boeing Company: Amendment 39-19466; Docket No. FAA- 2018-0415; Product 2017-NM-149-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective November 20, 2018. \n\n(b) Affected ADs \n\n\n\tNone. \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 any category. \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 53; Fuselage. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by the results of a fleet survey that revealed cracking in the bulkhead frame web at a certain body station. We are issuing this AD to address cracking in the station (STA) 259.5 bulkhead frame web from the first stiffener above stringers S-10 to S-13. Such cracking could result in reduced structural integrity of the airplane. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n((Page 52137)) \n\n(g) Required Actions for Group 1 Airplanes \n\n\n\tFor airplanes identified as Group 1 in Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017: Within 120 days after the effective date of this AD, inspect the airplane and do all applicable on-condition actions using a method approved in accordance with the procedures specified in paragraph (j) of this AD. \n\n(h) Required Actions for Group 2 and 3 Airplanes \n\n\n\tFor airplanes identified as Group 2 and 3 in Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017: Except as required by paragraph (i) of this AD, at the applicable times specified in the ''Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017. \n\n\n\tNote 1 to paragraph (h) of this AD: Guidance for accomplishing the actions required by this AD is included in Boeing Alert Service Bulletin 737-53A1369, dated October 12, 2017, which is referred to in Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017. \n\n(i) Exceptions to Service Information Specifications \n\n\n\t(1) For purposes of determining compliance with the requirements of this AD: Where Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017, uses the phrase ''the original issue date of Requirements Bulletin 737-53A1369,'' this AD requires using the effective date of this AD. \n\t(2) Where Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017, specifies contacting Boeing, this AD requires repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD. \n\n(j) Alternative Methods of Compliance (AMOCs) \n\n\n\t(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 (k) of this AD. Information may be emailed to: 9-ANM-LAACO-ACO-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, 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. \n\n(k) Related Information \n\n\n\tFor more information about this AD, contact George Garrido, Aerospace Engineer, Airframe Section,FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5232; fax: 562-627-5210; email: george.garrido@faa.gov. \n\n(l) 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 Requirements Bulletin 737-53A1369 RB, dated October 12, 2017. \n\t(ii) Reserved. \n\t(3) 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. \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, -500 series airplanes. The NPRM published in the Federal Register on May 25, 2018 (83 FR 24242). The NPRM was prompted by the results of a fleet survey that revealed cracking in the bulkhead frame web at a certain body station. The NPRM proposed to require repetitive inspections of the bulkhead frame web at a certain station, and repair if necessary. \n\tWe are issuing this AD to address cracking in the station (STA) 259.5 bulkhead frame web from the first stiffener above stringer S-10 to S-13. Such cracking could result in reduced structural integrity of the airplane. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA's response to each comment. \n\nRequest To Clarify Corrective Actions \n\n\n\tBoeing requested that the Summary section and Related Service Information paragraph in the NPRM be revised to clarify that the corrective actions include more than just repairs. Boeing stated that the service information does not describe defined repairs but indicates that if any crack is found, contact Boeing for repair instructions and do the repair and repeat the instructions. \n\tWe agree with the commenter's request for the reasons provided by the commenter. We have revised the Summary section of this final rule by changing ''repair if necessary'' to ''applicable on-condition actions.'' We have revised the ''Related Service Information under 1 CFR part 51'' paragraph of this final rule by clarifying the description of the service information to ''. . . low frequency eddy current inspections of the STA 259.5 bulkhead frame web from the first stiffener above stringer S-10 to S-13, on the left and right sides of the airplane and applicable on-condition actions.'' \n\nRequest To Include Group 1 Airplanes as Specified in the Service Information \n\n\n\tBoeing requested that Group 1 airplanes, as specified in Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017, be addressed in the body of the proposed AD. Boeing stated that this change would allow operators with airplanes that are not subject to the limit of validity a means to comply with the requirements specified in the proposed AD. \n\tWe agree with the commenter's request for the reasons provided by the commenter. Group 1 airplanes are those having line numbers 1 through 291 that have accumulated flight cycles beyond the limit of validity of the maintenance program. We have revised paragraph (g) of this AD to address Group 1 airplanes, added paragraph (h) of this AD to address Group 2 and 3 airplanes, and redesignated the subsequent paragraphs accordingly. \n\nEffect of Winglets on Accomplishment of the Proposed Actions \n\n\n\tAviation Partners Boeingstated that accomplishing the Supplemental Type Certificate (STC) ST01219SE does not affect the ability to accomplish the actions specified in the NPRM. \n\tWe concur with the commenter. We have redesignated paragraph (c) of the proposed AD as (c)(1) and added paragraph (c)(2) to this AD to state that installation of STC ST01219SE does not affect the ability to accomplish the actions required by this final rule. 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((Page 52136)) \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule with the changes described previously and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Boeing Alert Requirements Bulletin 737-53A1369 RB, dated October 12, 2017. The service information describes procedures for repetitive high frequency eddy current inspections and low frequency eddy current inspections of the STA 259.5 bulkhead frame web from the first stiffener above stringer S-10 to S-13, on the left and right sides of the airplane and applicable 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. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 411 airplanes of U.S.registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs for Required Actions ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Inspections.............. 57 work-hours x $85 per $0 $4,845 per $1,991,295 per \n\thour = $4,845 per inspection cycle. inspection cycle. \n\tinspection cycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that would 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 under 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.