Background \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to remove AD 2016-08-20, Amendment 39-18497 (81 FR 26103, May 2, 2016) (2016-08-20), and add a new AD. AD 2016-08-20 applied to Airbus Helicopters Model EC130B4 and EC130T2 helicopters with a junction frame that has 690 or more hours time-in-service (TIS) installed. The NPRM published in the Federal Register on March 5, 2021 (86 FR 12857). The NPRM proposed to require, for all Airbus Helicopters Model EC130B4 and EC130T2 helicopters with a junction frame: \n\tFor helicopters without MOD 074775, or MOD AH 350A087421 or SB EC130-53-029 installed, at a compliance time based on the hours TIS accumulated on the junction frame, removing the horizontal stabilizer, cleaning the junction frame, and visually inspecting the junction frame area for a crack, paying particular attention to the area around the 4 spars. \n\t(cir) Following the initial visual inspection, within 25 hours TIS or 390 sling cycles, whichever comes first, and thereafter at intervals not exceeding 25 hours TIS or 390 sling cycles, whichever comes first, either repeating the initial visual inspection, or, if the surface area is clean, borescope inspecting the junction frame area for a crack, paying particular attention to the area around the 4 spars. \n\t(cir) Also following the initial visual inspection, within 150 hours TIS and thereafter at intervals not to exceed 150 hours TIS, repeating the initial visual inspection. \n\tFor helicopters without MOD 074775 installed, but with MOD AH 350A087421 or SB EC130-53-029 installed, before the junction frame accumulates 350 hours TIS or within 10 hours TIS, whichever occurs later, visually inspecting for a crack on the junction frame area in each skin cut-out area. \n\t(cir) Following the initial visual inspection, within 10 hours TIS or 250 sling cycles, whichever occurs first, and thereafter at intervals not exceeding 10 hours TIS or 250 sling cycles, whichever occurs first, repeating the initial visual inspection. \n\t(cir) Also following the initial visual inspection, within 660 hours TIS and thereafter at intervals not to exceed 660 hours TIS, removing the horizontal stabilizer, cleaning the junction frame, and dye-penetrant inspecting the junction frame area for a crack, paying particular attention to the area around the 4 spars. \n\tIf there is a crack, replacing or repairing the junction frame in accordance with an FAA approved repair procedure before further flight. Repairing the junction frame would not constitute terminating action for the requirements of this AD. \n\tFor helicopters without MOD 074775 installed, with or without MOD AH 350A087421 or SB EC130-53-029 installed, without MOD 074609 or SB 53-024 installed, and on which the skin of the junction frame area has never been repaired, installing MOD 074775 within 24 months as of the effective date \n\n((Page 22342)) \n\nof this AD and reporting certain information to Airbus Helicopters within 30 days after installing MOD 074775. \n\tFor helicopters without MOD 074775 installed, with MOD 074609 or SB 53-024 installed, or on which the skin of the junction frame area has been previously repaired at any time, reinforcing the junction frame by replacing the two lateral splices which join the skins with four carbon patches (left-hand side, right-hand side, and lower sides) within 24 months as of the effective date of this AD. \n\tFor helicopters with MOD 074775 installed or with the four carbon patches reinforcements installed, but without MOD 074581 for Model EC130T2 helicopters, within 600 hours TIS after the installation of MOD 074775 or the reinforcement, and thereafter at intervals not exceeding 600 hours TIS, visually inspect the junction frame area for a crack. If there is a crack, replacing or repairing the junction frame in accordance with an FAA approved repair procedure before further flight. Repairing the junction frame would not constitute terminating action for the requirements of this AD. \n\tThe NPRM was prompted by a series of EASA ADs that have been issued since the FAA issued AD 2016-08-20, the most recent being EASA AD 2018- 0104, dated May 4, 2018 (EASA AD 2018-0104), 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 EC 130 B4 and EC 130 T2 helicopters, all serial numbers, except those with Airbus modification (MOD) 074775 installed. EASA's initial AD was prompted by two incidents of crack propagation through the junction frame that initiated in the lower right-hand side between the web and the flange where the lower spar of the tail boom is joined. EASA stated the cracks were of a significant length and not visible from the outside of the helicopter. EASA advised that this condition, if not detected, could lead to structural failure, possibly resulting in Fenestron detachment and consequent loss of control of the helicopter. \n\tAD 2016-08-20 was prompted by EASA AD 2015-0033-E, dated February 24, 2015 (EASA AD 2015-0033-E). Following EASA AD 2015-0033-E, EASA revised its AD to EASA AD 2015-0033R1, dated May 3, 2016 (EASA AD 2015- 0033R1), which was prompted by the determination that it was not necessary to inspect junction frames that had accumulated less than 1,200 flight hours. Accordingly, EASA AD 2015-0033R1 extended the inspection threshold from 700 flight hours to 1,200 flight hours. Thereafter, EASA issued EASA AD 2016-0240, dated December 2, 2016 (EASA AD 2016-0240) to supersede EASA AD 2015-0033R1. EASA AD 2016-0240 was prompted by a third incident of cracking in the same area of the junction frame as the first two incidents. Investigation determined that detection of the crack was delayed because of insufficient cleaning of the inspection area inside the junction frame. For that reason, EASA AD 2016-0240 retained the requirements of EASA AD 2015- 0033R1 and added additional cleaning requirements before inspecting. After EASA AD 2016-0240 was issued, a fourth incident of cracking in the same area of the junction frame as the first three incidents was reported. This fourth incident prompted EASA to issue EASA AD 2017- 0066-E, dated April 21, 2017 (EASA AD 2017-0066-E) to supersede EASA AD 2016-0240. This fourth incident occurred on a junction frame that had accumulated significantly less flight hours than the first three incidents. In light of this, EASA AD 2017-0066-E retained the requirements of EASA AD 2016-0240 and reduced the inspection threshold. Shortly after, EASA issued EASA AD 2017-0080, dated May 5, 2017 (EASA AD 2017-0080) to supersede EASA AD 2017-0066-E. EASA AD 2017-0080 was prompted by the determination that improved procedures to remove the horizontal stabilizer before cleaning and inspecting were necessary for certain helicopters. Accordingly, EASA AD 2017-0080 retained the requirements of EASA AD 2017-0066-E and added the improved procedures. Since EASA issued EASA AD 2017-0080, Airbus Helicopters developed MOD 074775, which consists of the installation of four carbon patches at the junction frame. Installation of MOD 074775, either in production or by retrofit, constitutes terminating action for the repetitive inspections. Based on the latest information, EASA determined that continued inspections may not adequately address the long-term risk and requires modifying the affected helicopters, which also terminates the repetitive inspections of the pre-modified configuration. Accordingly, EASA issued EASA AD 2018-0104 to supersede EASA AD 2017-0080 to require installation of MOD 074775. \n\nDiscussion of Final Airworthiness Directive \n\nComments \n\n\n\tThe FAA gave the public the opportunity to participate in developing this final rule, but the FAA did not receive any comments on the NPRM or on the determination of the cost to the public. \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 of the information provided by EASA 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 a minor editorial change of ''25 hours'' to ''25 hours TIS'' in Figure 1 to paragraph (f)(1) of this AD, this AD is adopted as proposed in the NPRM. \n\nDifferences Between This AD and the EASA AD \n\n\n\tEASA AD 2018-0104 does not apply to helicopters with MOD 074775, whereas this AD does. EASA AD 2018-0104 requires performing a local non-destructive inspection if in doubt about if there is a crack, whereas this AD does not. EASA AD 2018-0104 allows the pilotto visually inspect the junction frame from outside the tail boom for a crack, whereas this AD does not. EASA AD 2018-0104 requires contacting Airbus Helicopters if any crack is detected, whereas this AD requires replacing or repairing the junction frame in accordance with an FAA approved repair procedure instead. This AD requires a repetitive inspection for helicopters with MOD 074775 installed, whereas the EASA AD does not. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Airbus Helicopters Emergency Alert Service Bulletin No. 05A017, Revision 7, dated March 21, 2018, for Model EC130 B4 and T2 helicopters without MOD 074775 installed. This service information specifies procedures for cleaning inside the junction frame, inspecting the junction frame from the inside of the tail boom with the horizontal stabilizer both removed and installed for a crack, and inspecting the junction frame from the outside of the tail boom for a crack. \n\tThe FAA also reviewed Airbus Helicopters Service Bulletin No. EC130-53-036, Revision 4, dated April, 28, 2020, for Model EC130 B4 and T2 helicopters without MOD 074609 or 074775 installed and on which the skin \n\n((Page 22343)) \n\nof the junction frame area has not been repaired. This service information specifies procedures to reinforce the junction frame (MOD 074775) by replacing the two lateral splices which join the skins with four carbon patches (left-hand side, right-hand side, and lower sides). \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 reviewed Airbus Helicopters Service Bulletin No. EC130-53- 029, Revision 1, dated January 27, 2016. This service information specifies procedures to make a cut-out of the splice and skin at the junction frame (MOD 350A087421). \n\tThe FAA reviewed Airbus EC 130 B4 Chapter 4, Airworthiness Limitations Section, Revision 11, dated January 19, 2019, and EC 130 T2 Chapter 4, Airworthiness Limitations Section, Revision 9, dated September 9, 2019, which specify visually checking the junction frame for cracks at an interval of 600 flight hours with a margin of 60 flight hours. \n\tThe FAA also reviewed Airbus Helicopters Section 55-11-00, 6-4-- Horizontal Stabilizer--Inspection/Check, of Aircraft Maintenance Manual EC130, dated November 9, 2017, which specifies procedures for cleaning inside the junction frame and inspecting the junction frame from the inside of the tail boom with the horizontal stabilizer removed. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 263 helicopters of U.S. Registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates that operators may incur the following costs in order to comply with this AD. \n\tCleaning and inspecting the junction frame area with the horizontal stabilizer removed takes about 1 work-hour for an estimated cost of $85 per helicopter and $22,355 for the U.S. fleet, per inspection cycle. \n\tInternally borescope inspecting the junction frame area with the horizontal stabilizer installed takes about 0.5 work-hour for an estimated cost of $43 per helicopter and $11,309 for the U.S. fleet, per inspection cycle. \n\tIf applicable, cleaning and inspecting the junction frame area in each skin cut-out area takes about 1.25 work-hour for an estimated cost of $106 per helicopter and $27,878 for the U.S. fleet, per inspection cycle. \n\tModifying the junction frame skin reinforcements takes about 90 work-hours and parts cost about $10,000 for an estimated cost of $17,650 per helicopter and $4,641,950 for the U.S. fleet. Reporting certain information takes about 1 work-hour for an estimated cost of $85 per helicopter and $22,355 for the U.S. fleet. Inspecting the modified junction frame area takes about 1 work-hour for an estimated cost of $85 per helicopter and $22,355 for the U.S. fleet, per inspection cycle. \n\tIf required, repairing or replacing the junction frame takes up to 50 work-hours and parts cost about $60,000 for an estimated cost of $64,250 per helicopter. \n\tAccording to Airbus Helicopters' service information, 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 Airbus Helicopters. Accordingly, all costs are included in the cost estimate. \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 information 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 suggestions for 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, SubpartIII, 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\tThe FAA has 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\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Will not affect intrastate aviation inAlaska, 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.