Discussion \n\n\n\tThe EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2020-0037, dated February 27, 2020; corrected February 28, 2020 (''EASA AD 2020-0037'') (also referred to as the Mandatory Continuing Airworthiness Information, or ''the MCAI''), to correct an unsafe condition for certain Airbus SAS Model A318 series airplanes; Model A319-111, -112, -113, -114, -115, -131, - 132, and -133 airplanes; Model A320-211, -212, -214, -215, -216, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, - 213, -231, and -232 airplanes. Model A320-215 airplanes are not certificated by the FAA and are not included on the U.S. type certificate data sheet; this AD therefore does not include those airplanes in the applicability. \n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus SAS Model A318 series airplanes; Model A319-111, -112, -113, -114, -115, - 131, -132, and -133 airplanes; Model A320-211, -212, -214, -216, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, - 213, -231, and -232 airplanes. The NPRM published in the Federal Register on April 17, 2020 (85 FR 21334). The NPRM was prompted by a report that cracks were detected on the LH and RH sides of the first rivet hole of the FR43 foot coupling during scheduled maintenance. The NPRM proposed to require a rotating probe test of the fastener holes at FR43 on the LH and RH sides for any cracking, and on-condition actions if necessary, as specified in an EASA AD. \n\tThe FAA is issuing this AD to address cracking in the foot coupling, which could affect the structural integrity of the airplane. See the MCAI for additional background information. \n\nComments \n\n\n\tThe FAA 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\tOlivia Lawless stated support for the NPRM. \n\nRequest for Operator Training \n\n\n\tOlivia Lawless requested that training for operators should be implemented, or at least explored. The commenter stated concern about the implications that may result from requiring ''on-condition actions including a high frequency eddy current (rototest) inspection for cracks of the affected fastener holes, modification, and repair.'' The commenter noted that the NPRM suggests that the materials are available through the parties' normal course of business, however, it would be unlikely that employees would know how to perform these tests, or how to determine when on-condition actions occur without significant amounts of training. \n\tThe FAA agrees to clarify. The service information needed to comply with the required actions will be available in the AD docket. That service information contains detailed instructions for operators and their employees to follow. In addition, the FAA notes that it is the operators' responsibility to have adequate tools and provide adequate training for its employees to accomplish the required actions in an AD. The FAA has not changed this AD in this regard. \n\nRequest To Revise the Compliance Time \n\n\n\tDelta Airlines (DAL) requested that the compliance time be limited to flight cycles and not flight hours. DAL stated that Airbus Service Bulletin A320-53-1269, Revision 02, dated February 7, 2019, specifies that the cracks which prompted the development of modification 153126 and modification 153742, were identified as a part of the full scale fatigue test campaign. DAL commented that because the failure mode is fatigue driven, there is no reason to include a compliance time requirement based upon flight hours. \n\tThe FAA disagrees with the commenter's request. The requirements in this AD align with the requirements specified in EASA AD 2020-0037, which include compliance times in both flight hours and flight cycles. In addition, the FAA notes that the commenter did not submit any substantiating data to support using only a flight cycle requirement. However, under the provisions of paragraph (j)(1) of this AD, the FAA will consider requests for approval of a revision to the compliance time if sufficient data are submitted to substantiate that the change would provide an acceptable level of safety. The FAA has not changed this AD in this regard. \n\nRequest To Use an Alternate Chemical Corrosion Surface Pretreatment \n\n\n\tDAL requested the use of CML 10ABE1 as a more appropriate choice of a chemical corrosion surface pretreatment. DAL stated that after the cold expansion is completed using Airbus Structural Repair Manual (SRM) 51-48-00, but prior to the installation of the new fastener, Airbus Service Bulletin A320-53-1270, Revision 02, dated April 11, 2014, specifies an application of chemical conversion surface pretreatment CML 10ABC1, which is intended for use in fuel tankapplications. \n\tThe FAA disagrees with the commenter's request. The FAA has not received any information from either the state of design, EASA, or Airbus allowing alternate CML 10ABE1. CML 10ABC1 is a suitable pretreatment product that meets the requirements of this AD and addresses the identified unsafe condition. However, under the provisions of paragraph (j)(1) of this AD, the FAA will consider requests for approval of application of alternative chemical corrosion surface pretreatment products if sufficient data are submitted to substantiate that the change would provide an acceptable level of safety. The FAA has not changed this AD in this regard. \n\nRequest To Add an Exception to the NPRM \n\n\n\tDAL requested that the application of corrosion inhibiting compounds (CICs) be added to paragraph (h) of the proposed AD, ''Exceptions to EASA AD 2020-0037,'' and not be a requirement \n\n((Page 54895)) \n\nfor AD compliance. DAL stated that paragraph 3.C.(4)(c) of the Accomplishment Instructions of Airbus Service Bulletin A320-53-1270, Revision 02, dated April 11, 2014, requires that corrosion preventative compound CML 12ADB1 be applied to the cold worked area. DAL commented that each operator has a corrosion prevention and control program (CPCP) to control corrosion and may revise CIC products as necessary. DAL also commented that requiring the application of CML 12ADB1 within the required for compliance paragraph is problematic in maintaining perpetual compliance with the NPRM if a CPCP maintenance program task is applicable to the same area. \n\tThe FAA disagrees with the commenter's request. Since this AD affects multiple operators, and the FAA is not aware of the details of CIC compounds used as an inherent part of each operator's CPCP maintenance task, it is not practical for the FAA to revise this AD based on DAL's unique maintenance program. If DAL intends to use an approved substitution of the CIC that is not included in the SRM as an alternate to the CIC required by this AD, then DAL may request an alternative method of compliance (AMOC) under the provisions of paragraph (j)(1) of this AD. The FAA has not changed this AD regarding this issue. \n\nConclusion \n\n\n\tThe FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed, except for minor editorial changes. The FAA has 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\nRelated IBR Material Under 1 CFR Part 51 \n\n\n\tEASA AD 2020-0037 describes procedures for a rotating probe test (special detailed inspection) of the fastener holes at FR43 on the LH and RH sides for any cracking, and on-condition actions including a high frequency eddy current (rototest) inspection for cracks of the affected fastener holes, modification, and repair. \n\tThis material 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 867 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs for Required Actions ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tLabor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- 9 work-hours x $85 per hour = $765.............................. $0 $765 $663,255 ----------------------------------------------------------------------------------------------------------------The FAA estimates the following costs to do any necessary on- condition actions that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need these on-condition actions: \n\n\n\tEstimated Costs of On-Condition Actions ------------------------------------------------------------------------ \n\tCost per \n\tLabor cost Parts cost product ------------------------------------------------------------------------ 22 work-hours x $85 per hour = $1,870... $338 $2,208 ------------------------------------------------------------------------ \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 thisrulemaking 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.