AD 2021-08-12

The FAA is 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 crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting. This AD requires repetitive inspections for cracking of the left and right wing, lower aft wing skin aft edge, at certain flap track locations, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.

Final rule.

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: \n\n2021-08-12 The Boeing Company: Amendment 39-21506; Docket No. FAA- 2020-0587; Product Identifier 2020-NM-086-AD. \n\n(a) Effective Date \n\n\n\tThis airworthiness directive (AD) is effective May 28, 2021. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\tThis AD applies to all The Boeing Company Model 737-100, -200, - 200C, -300, -400, and -500 series airplanes, certificated in any category. \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 crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting. The FAA is issuing this AD to address undetected cracking in the lower wing skin, which could result in the inability of the structure to carry limit load, and adversely affect the 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(g) Required Actions \n\n\n\t(1) For all airplanes except those identified in paragraph (g)(2) of this AD, except as specified in paragraph (h) of this AD, at the applicable times specified in the ''Compliance'' paragraph in Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020. \n\t(2) For airplanes on which Aviation Partners Boeing blended winglets are installed using supplemental type certificate (STC) ST01219SE: Except as specified in paragraph (h) of this AD, at the applicable time in the ''Compliance'' paragraph in Aviation Partners Boeing Alert Service Bulletin AP737C-57-003, dated July 28, 2020, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020. \n\tNote 1 to paragraph (g): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-57A1349, dated April 14, 2020, which is referred to in Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020. \n\n(h) Exceptions to Service Information Specifications \n\n\n\t(1) Where Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020, uses the phrase ''the original issue date of Requirements Bulletin 737-57A1349 RB,'' this AD requires using ''the effective date of this AD.'' \n\t(2) Where Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020, specifies contacting Boeing for repair instructions: This AD requires doing the repair and applicable on- condition actions before further flight using a method approved in accordance with the procedures specified in paragraph (i) of this AD. \n\t(3) For airplanes identified as Group 1 in Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020: 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 (i) of this AD. \n\t(4) Where Aviation Partners Boeing Alert Service Bulletin AP737C-57-003, dated July 28, 2020, uses the phrase ''the original issue date of this service bulletin,'' this AD requires using ''the effective date of this AD.'' \n\t(5) Where Aviation Partners Boeing Alert Service Bulletin AP737C-57-003, dated July 28, 2020, specifies contacting Boeing for repair instructions: This AD requires doing the repair and applicable on-condition actions before further flight using a method approved in accordance with the procedures specified in paragraph (i) of this AD. \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 \n\n((Page 21637)) \n\nthe person identified in paragraph (j)(1) 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 responsible Flight Standards 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 Company 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(j) Related Information \n\n\n\t(1) For more information about this AD, contact Wayne Ha, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5238; fax: 562-627-5210; email: wayne.ha@faa.gov. \n\t(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (k)(3) and (5) of this AD. \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, unless the AD specifies otherwise. \n\t(i) Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020. \n\t(ii) Aviation Partners Boeing Alert Service Bulletin AP737C-57- 003, dated July 28, 2020. \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 90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. \n\t(4) For Aviation Partners Boeing service information identified in this AD, contact Aviation Partners Boeing, 2811 South 102nd St., Suite 200, Seattle, WA 98168; phone: 206-830-7699; fax: 206-767- 0535; email: leng@aviationpartners.com; internet: http://www.aviationpartnersboeing.com. \n\t(5) You may view this service information at the FAA, Airworthiness Products Section, Operational Safety 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(6) 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, email fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html. \n\n\n\tIssued on April 5, 2021. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service. (FR Doc. 2021-08508 Filed 4-22-21; 8:45 am) BILLING CODE 4910-13-P

Background \n\n\n\tThe FAA 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 July 28, 2020 (85 FR 45355). The NPRM was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting. \n\tThe FAA issued a supplemental notice of proposed rulemaking (SNPRM) 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 SNPRM published in the Federal Register on January 21, 2021 (86 FR 6276). The SNPRM was prompted by a determination that the compliance time should be reduced for airplanes on which Aviation Partners Boeing (APB) blended winglets have been installed using supplemental type certificate (STC) ST01219SE. The SNPRM proposed to require repetitive inspections for cracking of the left and right wing, lower aft wing skin aft edge, at certain flap track locations, and applicable on-condition actions. The FAA is issuing this AD to address undetected cracking in the lower wing skin, which could result in the inability of the structure to carry limit load, and adversely affect the structural integrity of the airplane. \n\nDiscussion of Final Airworthiness Directive \n\nComments \n\n\n\tThe FAA received no comments on the SNPRM or on the determination of the cost to the public. \n\nConclusion \n\n\n\tThe FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Except for minor editorial changes, this AD is adopted as proposed in the SNPRM. None of the changes will increase the economic burden on any operator. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020, and Aviation Partners Boeing Alert Service Bulletin AP737C-57-003, dated July 28, 2020. The service information describes procedures for repetitive high frequency eddy current inspections for cracking of the left and right wing, lower aft wing skin aft edge, at flap track numbers 1, 2, 3, 6, 7, and 8 attachment location and applicable on-condition actions. On-condition actions include repairing any cracking found. These documents are distinct since they apply to different airplane models in different configurations. \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\tThe FAA estimates that this AD affects 141 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: \n\n((Page 21636)) \n\n\n\n\n\n\n\tEstimated Costs for Required Actions ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- HFEC inspections............... 7 work-hours x $85 per $0 $595 per $83,895 per \n\thour = $595 per inspection cycle. inspection cycle. \n\tinspection cycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tThe FAA has received no definitive data that would enable providing 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\tThe FAA is 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\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) Will not affect intrastate aviation in Alaska, and \n\t(3) 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.