Discussion \n\n\n\tThe EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2017-0032, dated February 17, 2017; corrected February 20, 2017 (EASA AD 2017-0032) (also referred to as the \n\n((Page 13983)) \n\nMandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for all Airbus Helicopters Model AS 350 B, AS 350 BA, AS 350 BB, AS 350 B1, AS 350 B2, AS 350 B3, and AS 350 D helicopters; AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, AS 355 N, and AS 355 NP helicopters; and EC 130 B4 and EC 130 T2 helicopters. Model AS 350 BB helicopters 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 helicopters in the applicability. This AD also applies to Airbus Helicopter Model AS 350C helicopters because these helicopters have a similar design and are included on the U.S. type certificate data sheet. \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 Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, and AS350D helicopters; Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters; and Model EC130B4 and EC130T2 helicopters. The NPRM published in the Federal Register on December 15, 2020 (85 FR 81157). The NPRM was prompted by a report of failed main rotor hub-to- mast attachment screws. The NPRM proposed to require determining whether the helicopter has been operated in a severe environment since the last inspection of the main rotor hub-to-mast attachment screws, an inspection of the main rotor hub-to-mast attachment screws if the helicopter has been operated in a severe environment, and replacement of the main rotor hub-to-mast attachment screws if necessary, as specified in an EASA AD. \n\tThe FAA is issuing this AD to address failed main rotor hub-to-mast attachment screws, which could lead to disconnection of the main rotor hub-to-mast attachment, possibly resulting in loss of control of the helicopter. 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 FAA has considered the comments received. An individual indicated agreement with the NPRM. \n\nConclusion \n\n\n\tThe FAA reviewed the relevant data, considered the comment 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 Service Information Under 1 CFR Part 51 \n\n\n\tEASA AD 2017-0032 describes procedures for determining whether the helicopter has beenoperated in a severe environment since the last inspection of the main rotor hub-to-mast attachment screws, an inspection of the main rotor hub-to-mast attachment screws for corrosion and damage (damage includes cracks, dents, and bolt distortion) if the helicopter was operated in a severe environment, and replacement of the main rotor hub-to-mast attachment screws if necessary. This 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\nDifferences Between This AD and the MCAI \n\n\n\tEASA AD 2017-0032 does not apply to Airbus Helicopter Model AS350C helicopters, which are included on the U.S. type certificate data sheet. However, this AD applies to Airbus Helicopter Model AS350C helicopters because those helicopters have a similar design to the helicopters identified in EASA AD 2017-0032. \n\tWhere the service information specified in paragraph (3) of EASA AD 2017-0032 specifies to contact Airbus Helicopters if damage or corrosion exceeds existing criteria, this AD requires replacing the affected screws using a method approved by the Manager, International Validation Branch, FAA. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 1,220 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs for Required Determination of Helicopter Operation in a Severe Environment ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tLabor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- 1 work-hours x $85 per hour = $85............................ $0 $85 $103,700 ---------------------------------------------------------------------------------------------------------------- \n\n\n\tThe FAA estimates that it would take about 1 hour per product to comply with the reporting requirement in this AD. The average labor rate is $85 per hour. Based on these figures, the FAA estimates the cost of reporting the inspection results on U.S. operators to be $103,700, or $85 per product. \n\tThe FAA estimates the following costs to do any necessary on- condition actions that would be required based on the results of any required actions. If a helicopter is determined to have been operated in a severe environment, an inspection of the main rotor hub-to-mast attachment screws will be required. If there is corrosion or damage to any of the screws, replacement of the affected screws will be required. 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 ------------------------------------------------------------------------Cost per \n\tLabor cost Parts cost product ------------------------------------------------------------------------ 4 work-hours x $85 per hour = $340.... $106 $446 ------------------------------------------------------------------------ \n\n\n\n((Page 13984)) \n\nPaperwork Reduction Act \n\n\n\tA federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB control number. The control number for the collection of information required by this AD is 2120- 0056. The paperwork cost associated with this AD has been detailed in the Costs of Compliance section of this document and includes time for reviewing instructions, as well as completing and reviewing the collection of information. Therefore, all reporting associated with this AD is mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Pkwy., Fort Worth, TX 76177-1524. \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.