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 Airbus Model A318, A319, and A320 series airplanes. The NPRM published in the Federal Register on November 27, 2015 (80 FR 74045) (''the NPRM''). \n\tThe European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2014-0259, dated December 5, 2014 (referred to after this as the Mandatory Continuing Airworthiness Information, or ''the MCAI''), to correct an unsafe condition for certain Airbus Model A318, A319, and A320 series airplanes. The MCAI states: \n\n\n\tAn operator reported finding chafing damage on the fuselage skin at the bottom of frame (FR) 34 junction between stringer (STR) 43 left hand (LH) side and right hand (RH) side on several aeroplanes, underneath the fairing structure. \n\tAfter investigation, a contact between the fairing nut plate and the fuselage was identified, causing damage to the fuselage. \n\tThis condition, if not detected and corrected, could lead to crack initiation and propagation, possibly resulting in reduced structural integrity of the fuselage. \n\tFor the reason described above, this (EASA) AD requires repetitive detailed inspections (DET) of the fuselage (for chafing) at FR 34 and provides an optional terminating action (modification of the belly fairing) to the repetitive inspections required by this (EASA) AD. \n\n\n\tRelated investigative actions include a special detailed inspection of external fuselage skin panel for any cracking, and measurement of crack length and remaining thickness. Corrective actions include repair or modification of the fuselage skin panel. You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-5814. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD.The following presents the comments received on the NPRM and the FAA's response to each comment. \n\nRequest To Use Latest Service Information \n\n\n\tAirbus requested that we revise paragraph (i) of the NPRM to add Airbus Service Bulletin A320-53-1281, Revision 02, including Appendix 01, dated October 9, 2015. \n\tUnited Airlines also requested that we revise paragraph (i) of the NPRM to add Airbus Service Bulletin A320-53-1281, Revision 02, including Appendix 01, dated October 9, 2015, and provide credit for Airbus Service Bulletin A320-53-1281, Revision 01, dated December 1, 2014. United Airlines explained that Airbus Service Bulletin A320-53- 1281, Revision 02, including Appendix 01, dated October 9, 2015, includes numerous configuration additions. \n\tFor the reasons stated by the commenter, we agree to revise this AD to include Airbus Service Bulletin A320-53-1281, Revision 02, including Appendix 01, dated October 9, 2015. Airbus Service Bulletin A320-53- 1281, Revision 02, including Appendix 01, \n\n((Page 61994)) \n\ndated October 9, 2015, includes, among other things, configuration changes, new configurations, and revision of the Manufacturer Serial Numbers (MSNs), but adds no new actions. We also included Airbus Service Bulletin A320-53-1281, Revision 01, dated December 1, 2014, in paragraph (j) of this AD, as credit for certain actions performed before the effective date of this AD. \n\nRequest To Allow Use of Any Airbus-Approved Corrective Action \n\n\n\tAirbus requested that we revise the NPRM to add a paragraph that allows for any corrective action provided by Airbus. Airbus stated that in case of deviation during service information embodiment, the only solution to cover the deviation for the customer is to ask for an alternative method of compliance (AMOC). Airbus included the following example, which allows any corrective action provided by Airbus: \n\n\n\tIf, during modification of an aeroplane as required by paragraph (1) of this AD, a difference (seeNote) is detected which makes the accomplishment of a part of the modification instructions impossible, before next flight, contact Airbus for approved instructions and accomplish those instructions accordingly, including follow-on action(s), as applicable. \n\tNote: For the purpose of this AD, the detected difference can be either: \n\t(a) a necessary design deviation due to production related concessions that directly affect the sensitive area of the modification; \n\t(b) an obvious typographical error in the SB instructions; or \n\t(c) an aircraft configuration not (yet) included in/addressed by the SB instructions. \n\nWe disagree to add a paragraph that allows for any corrective action provided by Airbus, because CFR 39.19 requires approval of an AMOC for an alternative method to mitigate the risk associated with the unsafe condition addressed in an AD. The FAA uses its discretion in determining actions within the provision of an AMOC. We have made no changes to this AD in this regard. \n\nRequest To Clarify Steps Required for Compliance \n\n\n\tUnited Airlines requested that we revise the NPRM to clarify that the actions that are required for compliance (RC) are limited to the steps in paragraphs 3.C. and 3.D. of Airbus Service Bulletin A320-53- 1287, dated July 29, 2014; Airbus Service Bulletin A320-53-1281, Revision 02, including Appendix 01, dated October 9, 2015; and Airbus Service Bulletin A320-53-1281, Revision 01, dated December 1, 2014. The commenter noted that paragraph 3.D. contains no test requirements. \n\tWe agree with the request, although, as the commenter noted, paragraph 3.D. of the referenced service information does not include any test requirements. We have therefore revised paragraphs (g) and (i) of this AD to limit the requirements to paragraph 3.C., ''Procedure,'' of the service information. \n\nRequest for Clarification of Compliance Methods and Intervals \n\n\n\tUnited Airlines requested that we clarify whether the inspections specified in the NPRM and Airbus Service Bulletin A320-53-1287, dated July 29, 2014, override the inspection methods and intervals defined in structures repair manual (SRM) 53-21-11 PB 101, and whether the terminating action in paragraph (i) of the proposed AD terminates the inspections in SRM 53-21-11 PB 101 following rework. The commenter stated that SRM 53-21-11 PB 101 defines different inspection methods, threshold, and repetitive intervals. \n\tWe agree that clarification is necessary. We recognize that there may be a conflict between the inspections specified in this AD and SRM 53-21-11 PB 101. The requirements of this AD were developed to address a known unsafe condition and prevail over the actions of previously developed service information provided by a manufacturer. We have made no changes to this AD in this regard. \n\nRequest for Clarification of Limit \n\n\n\tUnited Airlines requested that we revise paragraph (g)(3) of the proposed AD to clarify the ''limits'' of detected damage. Paragraph (g)(3) of the proposed AD refers to damage that exceeds the limits defined in Airbus Service Bulletin A320-53-1287, dated July 29, 2014. United Airlines noted that this limit relates to the remaining skin thickness as defined by SRM 53-21-11 PB 101, but the meaning of ''remaining thickness out of limits'' is inconclusive. United Airlines stated that the remaining skin thickness following a blend out could become a Category 'B' repair with subsequent inspections or a Category 'C' repair, eventually requiring doubler repair. United Airlines stated that Airbus Service Bulletin A320-53-1287, dated July 29, 2014, does not give instructions to accomplish a doubler repair if the remaining thickness is within SRM 53-21-11 PB 101 limits. United Airlines stated that it would not be wise to install an external doubler (unless necessary) if the remaining skin thickness is ''within limits.'' The commenter therefore proposed that we clarify the ''limit'' as an allowable rework (blend out) that does not require repair (doubler installation). \n\tWe agree that clarification is necessary. If Subtask 531287-832- 002-001 of Airbus Service Bulletin A320-53-1287, dated July 29, 2014, is performed, and no crack is found, and the measurement of the remaining thickness of fuselage skin exceeds certain limits, then Airbus Service Bulletin A320-53-1287, dated July 29, 2014, specifies contacting Airbus for repair instructions. The corresponding requirement in paragraph (g)(3) of this AD, requires that those repairs be done using a method approved by the FAA, EASA, or Airbus's EASA Design Organization Approval. Repair instructions are established based on the inspection results shared with Airbus, which may vary on a case- by-case basis. We have made no changes to this final rule in this regard. \n\nRequest for Inclusion of Previously Repaired Area in Inspection \n\n\n\tUnited Airlines requested that we revise paragraph (g)(1) of the proposed AD to include damage on the ''fuselage skin or skin repair (if present)'' for the required detailed inspection. United Airlines explained that it experienced several issues of skin chafing prior to the release of Airbus Service Bulletin A320-53-1287, dated July 29, 2014; as a result, some airplanes have needed doubler repairs due to skin wear beyond remaining thickness allowed. The commenter stated that because repairs may be present, it will not be possible to inspect the skin in the chafing area. \n\tFor the reasons stated by the commenter, we agree to include previously repaired areas for the inspection required by paragraph (g)(1) of this AD. We have revised paragraph (g)(1) of this AD accordingly. \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 AD 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 correcting 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 AD. \n\n((Page 61995)) \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tWe reviewed Airbus Service Bulletin A320-53-1281, Revision 02, including Appendix 01, dated October 9, 2015; and Airbus Service Bulletin A320-53-1287, dated July 29, 2014. The service information describes procedures for a detailed inspection for damage (including chafing marks) on the fuselage skin at FR 34 between STR 43 LH and RH sides, and applicable related investigative and corrective 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 affects642 airplanes of U.S. registry. \n\tWe also estimate that it would take about 12 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Required parts would cost about $90 per product. Based on these figures, we estimate the cost of this AD on U.S. operators to be $712,620, or $1,110 per product. \n\tIn addition, we estimate that any necessary follow-on actions would take about 21 work-hours and require parts costing $3,550, for a cost of $5,335 per product. We have no way of determining the number of aircraft that might need this action. \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 ''SubtitleVII, 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\tWe determined that this 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\t1. Is not a ''significant regulatory action'' under Executive Order 12866; \n\t2. Is not a ''significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); \n\t3. Will not affect intrastate aviation in Alaska; and \n\t4. 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.