Background \n\n\n\tEASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2016-0166-E, dated August 12, 2016 and corrected October 4, 2017 (EASA AD 2016-0166-E), to correct an unsafe condition for Leonardo S.p.A. (formerly AgustaWestland S.p.A., Agusta S.p.A., Costruzioni Aeronautiche Giovanni Agusta) Model AB204B, AB205A1, and AB212 helicopters, all serial numbers (S/Ns), and AB412 helicopters all S/Ns up to S/N 25669 inclusive. EASA advises that a crack was found in a spiral bevel gear part number (P/N) 204-040-701- 103 during a scheduled inspection of a main rotor (M/R) transmission P/ N 212-040-001-59. The initial investigation determined that the crack originated from the bottom of one of the 32 threaded holes. EASA further advises that other spiral bevel gears manufactured with the same process as the defective one could be affected by the same issue. This condition, if not addressed, could lead to failureof the M/R transmission and possible loss of control of the helicopter. \n\tAccordingly, EASA AD 2016-0166-E requires a one-time visual inspection and a recurring FMPI of certain serial-numbered spiral bevel gears P/N 204-040-701-103 for a crack, and if there is a crack, replacing the spiral bevel gear or the M/R transmission. EASA AD 2016- 0166-E also prohibits installing an affected spiral bevel gear unless it is a serviceable part. EASA considers its AD an interim action and states that further AD action may follow. \n\nFAA's Determination \n\n\n\tThis model helicopter has been approved by EASA and is 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 is issuing this AD after evaluating all known relevant information and determining that the unsafe condition described previously is likely to exist or develop on other helicopters of the same type design. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Finmeccanica Helicopter Division (FHD) Alert Bollettino Tecnico No. 412-146, Revision A, dated July 7, 2016. This service information specifies procedures for a one-time visual inspection of the spiral bevel gear by marking one tooth of the spiral bevel gear with white chalk (or equivalent), and with the aid of a light source, rotating the tail rotor blades, and visually inspecting the teeth of the spiral bevel gear for a crack. This service information also specifies procedures for a recurring FMPI of the spiral bevel gear for a crack. If there is a crack, this service information \n\n((Page 19128)) \n\nspecifies removing the spiral bevel gear from service and reporting findings to FHD Product Support Engineering. \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\nAD Requirements \n\n\n\tThis AD requires a one-time visual inspection and a recurring FMPI of certain serial-numbered spiral bevel gears P/N 204-040-701-103 for a crack, and if there is a crack, removing the spiral bevel gear from service. This AD also prohibits installing an affected spiral bevel gear unless it has previously passed an FMPI within less than 300 hours time-in-service. \n\nDifferences Between This AD and the EASA AD \n\n\n\tEASA AD 2016-0166-E applies to Model AB204B, AB205A1, and AB212 helicopters, whereas this AD does not because those model helicopters are not FAA type-certificated. EASA AD 2016-0166-E applies to certain serial-numbered helicopters, whereas this AD applies to certain serial- numbered helicopters with certain serial-numbered spiral bevel gears P/ N 204-040-701-103 installed instead. EASA AD 2016-0166-E also includes a compliance time of before the spiral bevel gear accumulates 1,200 flight hours since first installation on a helicopter, whereasthis AD does not. \n\nInterim Action \n\n\n\tThe FAA considers this AD to be an interim action. If final action is later identified, the FAA might consider further rulemaking then. \n\nJustification for Immediate Adoption and Determination of the Effective Date \n\n\n\tSection 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for ''good cause,'' finds that those procedures are ''impracticable, unnecessary, or contrary to the public interest.'' Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause. There are no helicopters with this type certificate on the U.S. Registry. Accordingly, notice and opportunity for prior public comment are unnecessary, pursuant to 5 U.S.C. 553(b)(3)(B). \n\tIn addition, for the foregoing reason(s), the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\n\tThe FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under ADDRESSES. Include ''Docket No. FAA-2017-1077; Project Identifier 2016- SW-070-AD'' at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments. \n\tExcept for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to https://www.regulations.gov, includingany personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule. \n\nConfidential Business Information \n\n\n\tCBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as ''PROPIN.'' The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to Rao Edupuganti, Aerospace Engineer, Dynamic Systems Section,Technical Innovation Policy Branch, Policy & Innovation Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email rao.edupuganti@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. \n\nRegulatory Flexibility Act \n\n\n\tThe requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required. \n\nCosts of Compliance \n\n\n\tThere are no costs of compliance with this AD because there are no helicopters with this type certificate on the U.S. Registry. \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 theauthority 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, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, and \n\t(2) Will not affect intrastate aviation in Alaska. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.