AD 2018-18-03

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by several reports of cracks in a certain floor beam lower chord at door stop fitting No. 1 of the forward airstair door cutout. This AD requires repetitive inspections for any cracks 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\n2018-18-03 The Boeing Company: Amendment 39-19382; Docket No. FAA- 2018-0273; Product Identifier 2018-NM-017-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective October 15, 2018. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\t(1) This AD applies to The Boeing Company Model 737-100, -200, - 200C, -300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Requirements Bulletin 737- 53A1370 RB, dated December 13, 2017. \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 52, Doors; 53, Fuselage. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by several reports of cracks in the station (STA) 312 floor beam lower chord at door stop fitting No. 1 of the forward airstair door cutout. We are issuing this AD to address such cracking, which could result in the inability of a principal structural element to sustain limit loads and possible rapid decompression. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Required Actions \n\n\n\t(1) For airplanes identified as Group 1 in Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017: Within120 days after the effective date of this AD, inspect the STA 312 floor beam lower chord and door stop fittings No. 2, No. 5 and No. 8 for any cracks and do applicable on-condition actions, using a method approved in accordance with the procedures specified in paragraph (i) of this AD. \n\t(2) Except as required by paragraph (h) of this AD: For airplanes identified as Group 2 in Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, at the applicable times specified in the ''Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017. \n\n\n\tNote 1 to paragraph (g)(2) of this AD: Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-53A1370, dated December 13, 2017, which is referred to in \n\n((Page 45550)) \n\nBoeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017. \n\n(h) 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 737-53A1370 RB, dated December 13, 2017, uses the phrase ''the original issue date of Requirements Bulletin 737-53A1370 RB,'' this AD requires using ''the effective date of this AD.'' \n\t(2) Where Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, specifies contacting Boeing, this AD requires repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD. \n\t(3) Where Step 2. of Appendix A of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, specifies ''Electrically close the door,'' this AD allows closing the door electrically or manually. \n\t(4) Where Step 6. of Appendix A of Boeing Alert Requirements Bulletin 737-53A1370 RB,dated December 13, 2017, specifies to ''Cycle the door electrically and make sure it operates smoothly,'' this AD allows cycling the door electrically or manually and making sure it operates smoothly. \n\n(i) 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 (j) 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, 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\t(4) Except as required by paragraph (h) of this AD: For service information that contains steps that are labeled as RC, the provisions of paragraphs (i)(4)(i) and (i)(4)(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 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. \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(j) Related Information \n\n\n\tFor more information about this AD, contact Galib Abumeri, Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5324; fax: 562-627-5210; email: galib.abumeri@faa.gov. \n\n(k) 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, unlessthe AD specifies otherwise. \n\t(i) Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 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 certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on April 13, 2018 (83 FR 16010). The NPRM was prompted by several reports of cracks in a certain floor beam lower chord at door stop fitting No. 1 of the forward airstair door cutout. The NPRM proposed to require repetitive inspections for any cracks and applicable on-condition actions. \n\tWe are issuing this AD to address such cracking, which could result in the inability of a principal structural element to sustain limit loads and possible rapid decompression. \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\nSupport for the NPRM \n\n\n\tBoeing stated that it concurs with the NPRM. \n\nEffect of Winglets on Accomplishment of the Proposed Actions \n\n\n\tAviation Partners Boeing stated that accomplishing supplemental type certificate (STC) ST01219SE does not affect the actions specified in the NPRM. \n\tWe agree with the commenter's request. We have redesignated paragraph (c) of the proposed AD as paragraph (c)(1) of this AD 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 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\nRequest To Allow Manual Operation of Airstair Door \n\n\n\tSwiftair S.A. requested that a note be included in this AD to allow for fully manual operation of the forward airstair door instead of the electrical operation as specified in Appendix A of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017. Swiftair S.A. observed that two steps in Appendix A of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, cannot be performed on aircraft that have incorporated Boeing Service Bulletin 737-52-1092. Boeing Service Bulletin 737-52-1092 provides instructions for temporary or permanent removal of the forward airstair assembly, deactivation of the electrical system, and removal of the forward airstair door motor, among other actions. \n\tWe agree because the forward airstair door cannot be operated electrically if the electrical system is deactivated and the motor is removed. We have changed paragraph (h) of this AD to include exceptions to certain steps of Appendix A of Boeing Alert Requirements Bulletin 737-53A1370 RB, dated December 13, 2017, that allow for both manual and electrical operation of the airstair door. \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 737-53A1370 RB, dated December 13, 2017. The service information describes procedures for repetitive high frequency \n\n((Page 45549)) \n\neddy current inspections of the station (STA) 312 floor beam lower chord, and door stop fittings No. 2, No. 5, and No. 8 on the forward airstair door for any cracks 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 67 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 ---------------------------------------------------------------------------------------------------------------- Inspection............... Up to 11 work-hours x $0 Up to $935 per Up to $62,645 per \n\t$85 per hour = $935 inspection cycle. inspection cycle. \n\tper inspection 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'' underExecutive 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.