Discussion \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 Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. The NPRM published in the Federal Register on April 13, 2020, (85 FR 20447). The NPRM proposed to require visually inspecting each MGB suspension bar attachment bracket for missing bolt heads. If one bolt head is missing, the proposed AD would require performing actions specified in the service information including measuring the tightening torque of the remaining bolts of that bracket, removing the attachment bracket bolts, washers, and nuts of that bracket, and sending photos and reporting certain information to Airbus Helicopters. The proposed AD would also require repairs in accordance with an FAA-approved method if two or more bolt heads are missing. The proposed requirements were intended to prevent failure of the MGB suspension bar attachment bolts due to fatigue. \n\tThe NPRM was prompted by EASA AD No. 2018-0152, dated July 18, 2018 (EASA AD 2018-0152), issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for Airbus Helicopters (formerly Eurocopter, Eurocopter France) Model AS 350 B, AS 350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350 B3, EC 130 B4, EC 130 T2, AS 355 E, AS355 F, AS355 F1, AS 355 F2, AS 355 N, and AS355 NP helicopters. EASA advises of a reported occurrence of a missing MGB suspension bar attachment bolt head. \n\tEASA advises that investigations are ongoing to determine the root cause of this event. According to Airbus Helicopters, the missing MGB suspension bar attachment bolt head was discovered during scheduled maintenance of a Model EC 130 T2 helicopter. EASA states this condition could lead to fatigue failure of other affectedbolts of the same MGB bracket, possibly resulting in loss of the MGB suspension bar and consequently loss of helicopter control. As an interim measure to address this potential unsafe condition, the EASA AD also includes Model AS 350 B, AS 350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350 B3, EC 130 B4, AS 355 E, AS355 F, AS355 F1, AS355 F2, AS355 N, and AS355 NP helicopters in its applicability. \n\tAccordingly, EASA AD 2018-0152 requires a one-time visual inspection to check that all MGB suspension bar attachment bracket bolt heads are present and depending on the outcome, measuring the tightening torque values of the bolts, removing and sending bolts, washers, and nuts to Airbus Helicopters, installing new bolts, washers, and nuts, sending photos and reporting certain information to Airbus Helicopters, and \n\n((Page 71236)) \n\ncontacting Airbus Helicopters for approved repair instructions. EASA states EASA AD 2018-0152 is considered an interim action and further AD action may follow. \n\nComments \n\n\n\tThe FAA gave the public the opportunity to participate in developing this final rule. The FAA received comments from one commenter. The following presents the comments received on the NPRM and the FAA's response to the comments. \n\nRequest \n\n\n\tThe commenter requested that this AD apply to Model AS350B3 and higher model helicopters, specifically Model AS350B3, AS350B3E, EC130B4, EC130T2, H125, and H130 helicopters. The commenter stated that, based on experience with a fleet of AS350BA and AS350B2 helicopters, the commenter has never seen a bolt head break on Model AS350BA and AS350B2 helicopters. \n\tThe FAA disagrees with removing models from the Applicability. The FAA determined that the unsafe condition exists and is likely to exist or develop on all the model helicopters included in the Applicability and is therefore requiring corrective action to address this unsafe condition on these models. \n\nRequest \n\n\n\tThe commenter requested the manufacturer add the inspection proposed in the NPRM to the 660-hour ''T'' inspection and also add the inspection after a certain number of flight hours after installation. The commenter gave an example of after 165 flying hours. \n\tThe FAA disagrees; the commenter provided no technical justification for changing the compliance times. \n\nActions Since Issuance of the NPRM \n\n\n\tAfter the NPRM was issued, the FAA discovered that Airbus Helicopters Model AS350C was inadvertently included in the proposed Applicability. This helicopter model has a different engine model and therefore is not subject to the unsafe condition. The FAA has updated the Applicability section accordingly. \n\nFAA's Determination \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 of the unsafe condition described in its AD. The FAA is issuing this AD after evaluating all information provided by EASA, reviewing the relevant information, considering the comments received, and determining the unsafe condition exists and is likely to exist or develop on other helicopters of these same type designs and that air safety and the public interest require adopting the AD requirements as proposed except for the change described previously. The FAA has determined that this change is consistent with the intent that was proposed for addressing the unsafe condition and does not add any additional burden upon the public than was already proposed in the NPRM except for minor editorial changes. These minor editorial changes are consistent with the intent of the proposals in the NPRM and will not increase the economic burden on any operator nor increase the scope of this AD. \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. \n\nDifferences Between This AD and the EASA ADThe EASA AD applies to Model AS350BB helicopters, whereas this AD does not because that model is not FAA type-certificated. The EASA AD directs the operators to contact Airbus Helicopters for repairs if more than one screw head is missing, whereas this AD does not. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Airbus Helicopter Alert Service Bulletin (ASB) No. AS350-05.00.92 for Model AS350B, B1, B2, B3, BA, and D helicopters, non-FAA type-certificated Model AS350BB helicopters, and military Model AS350L1 helicopters; Airbus Helicopters ASB No. AS355-05.00.79 for Model AS355E, F, F1, F2, N, and NP helicopters; and Airbus Helicopters ASB No. EC130-05A028 for Model EC130B4 and T2 helicopters, all Revision 0 and dated July 16, 2018. This service information specifies a one- time visual inspection using a light source and a mirror, and using an endoscope for any attachment bolts that are difficult to access, for the presence of the 16 attachment bracketbolt heads of the 4 MGB suspension bars. The service information also specifies different actions depending on the results of the visual inspection. \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\nOther Related Service Information \n\n\n\tThe FAA also reviewed Airbus Standard Practices Manual (MTC) 20-02- 05-404, Assembly by screws and nuts Joining, dated May 23, 2017. This service information specifies instructions for installing screws and nuts, tightening procedures when installing multiple bolts, tightening torque check and readjustment procedures, tooling information, measuring locking torque procedures, standard tightening torque procedures and values, torque tightening of screws in sandwich panels information, use of consumable materials and their correction coefficient values pertaining to screws, nuts, and washers, marking torquestripes, and re-installation criteria and inspection of attachment components. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 1,277 helicopters of U.S. Registry. The FAA estimates that operators may incur the following costs in order to comply with this AD. Labor costs are estimated at $85 per work-hour. \n\tInspecting for any missing MGB suspension bar attachment bracket bolt heads takes about 2 work-hours for an estimated cost of $170 per helicopter and $217,090 for the U.S. fleet. \n\tMeasuring the tightening torque of three MGB suspension bar attachment bracket bolts and replacing the set of four MGB suspension bar attachment bracket bolts, washers, and nuts takes about 1 work-hour and parts cost about $50 for an estimated cost of $135 per helicopter. \n\tSending photos and reporting required information takes about 1 hour for an estimated cost of $85 per helicopter. \n\tThe FAA does not have the data to estimate the costs to do any FAA- approved repairs if two or more MGB suspension bar attachment bracket bolt heads are missing. \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 a 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 currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of \n\n((Page 71237)) \n\ninformation is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestionsfor reducing this burden to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, 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 helicopters identifiedin 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\t1. Is not a ''significant regulatory action'' under Executive Order 12866, \n\t2. Will not affect intrastate aviation in Alaska, and \n\t3. 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.