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 Leonardo Model A109S and AW109SP helicopters with a vertical fin vibration absorber installation part number (P/N) 109-B810-79-101 installed. The NPRM published in the Federal Register on May 13, 2021 (86 FR 26198). In the NPRM, the FAA proposed, within 30 hours time-in-service (TIS), and thereafter at intervals not to exceed 100 hours TIS, removing the vertical fin vibration absorber installation and, using a mirror and light source, inspecting the rib assembly and depending on the inspection results, removing certain parts from service. The NPRM also proposed to require inspecting the vertical fin vibration absorber installation for hole elongation; for fretting between the plate and the masses, and in between the masses; for fretting on the doubler; and the bolts for scratches and corrosion. Depending on the inspection results, the NPRM proposed removing the vertical fin vibration absorber installation from service. The NPRM also proposed to require, within 12 months TIS, removing the vertical fin vibration absorber installation from service. Finally, the NPRM proposed to prohibit installing an affected part on any helicopter, and provided a terminating action for the 100-hour TIS repetitive inspections. \n\tThe NPRM was prompted by EASA AD 2014-0150, dated June 18, 2014 (EASA AD 2014-0150), issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for certain AgustaWestland S.p.A. (now Leonardo S.p.a. Helicopters) (formerly Agusta S.p.A.) Model A109S and AW109SP helicopters with an absorber P/N 109-B810-79-101installed. EASA advises that during a scheduled inspection on Model A109S and AW109SP helicopters, cracks and damage were detected on the vertical fin vibration absorber installation and the surrounding structure. EASA stated that investigation results determined the \n\n((Page 46114)) \n\ncracks and damage were likely related to the design of the vertical fin vibration absorber installation and incorrect installation. Accordingly, EASA AD 2014-0150 required repetitive inspections and removal of the affected part. \n\tAfter EASA AD 2014-0150 was issued, EASA determined certain helicopters were not included in the applicability and may also be subject to the unsafe condition. Accordingly, EASA issued EASA AD 2019- 0294, dated December 4, 2019 (EASA AD 2019-0294), which supersedes EASA AD 2014-0150. EASA AD 2019-0294 retains the requirements of EASA AD 2014-0150 and expands the applicability, prohibits vertical fin vibration absorber installation P/N 109-B810-79-101 from being installed on any helicopter, and considers removal of the affected part to constitute terminating action for the repetitive inspections. EASA states that the unsafe condition, if not detected and corrected, could affect the structural integrity ofthe helicopter. \n\nDiscussion of Final Airworthiness Directive \n\nComments \n\n\n\tThe FAA received no comments on the NPRM or on the determination of the costs. \n\nConclusion \n\n\n\tThese helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the European Union, EASA has notified the FAA about the unsafe condition described in its AD. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed except for a correction to the compliance time for removing the vertical fin vibration absorber installation from service. The NPRM stated that removing this part from service would be required ''within 12 months TIS''; the term ''TIS'' was included in error and has been removed. This change does not increase the economic burden on any operator. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters. \n\nRelated Service Information \n\n\n\tThe FAA reviewed AgustaWestland S.p.A. Bollettino Technico No. 109S-58 for Model A109S helicopters, and AgustaWestland S.p.A Bollettino Technico No. 109SP-074 for Model AW109SP helicopters, each dated May 7, 2014. This service information specifies instructions for removing the vertical fin vibration absorber installation, inspecting the rib assembly and vertical fin vibration absorber installation and depending on the inspection results, removing certain parts from service. \n\nDifferences Between This AD and the EASA AD \n\n\n\tEASA AD 2019-0294 applies to certain serial-numbered Model A109S and AW109SP helicopters, whereas this AD applies to all serial-numbered Model A109S and AW109SP helicopters with a certain part-numbered vertical fin vibration absorber installation installed. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 96 helicopters of U.S. Registry and that operators may incur the following costs in order to comply with this AD. Labor costs are estimated at $85 per work-hour. \n\tRemoving and inspecting the vertical fin vibration absorber installation and surrounding structure takes about 8 work-hours for an estimated cost of $680 per helicopter per inspection cycle and $65,280 for the U.S. fleet per inspection cycle. \n\tReplacing the rib assembly, shim, doubler, and bracket will take about 16 work-hours and parts will cost about $10,000 for an estimated cost of $11,360 per helicopter. \n\tAccording to Leonardo some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. The FAA does not control warranty coverage by Leonardo. Accordingly, all costs are included in this cost estimate. \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 theAgency'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 helicopters 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.