Discussion \n\n\n\tThe FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to Pacific Scientific Company buckle part numbers (P/Ns) 1111430 and 1111475, all dash numbers. The SNPRM published in the Federal Register on September 24, 2020 (85 FR 60100). The FAA preceded the SNPRM with a notice of proposed rulemaking (NPRM) that published in the Federal Register on September 5, 2013 (78 FR 54594). The NPRM proposed to require inspecting each buckle for a crack and the thickness of the buckle handle vane. Depending on the inspection results, the NPRM proposed to require replacing the buckle. The NPRM also proposed to prohibit installing an affected buckle on any helicopter or airplane. The SNPRM proposed to the same requirements except with longer compliance times to accomplish the inspections. The SNPRM also corrected the name of Pacific Scientific Aviation Services to Pacific Scientific Company, updated the estimated costs of compliance, edited the Applicability paragraph by adding a note to clarify that an affected buckle could be included as a component of a different part-numbered restraint system assembly and reference Appendix 1 of Pacific Scientific Service Bulletin SB 25-1111432, dated May 22, 2007 (SB 25-1111432), which lists the P/Ns of potentially affected restraint systems, updated the names of certain potentially-affected Type Certificate holders, and updated the contact information name and contact \n\n((Page 17704)) \n\ninformation from Pacific Scientific Aviation Services to Meggitt Services. \n\tThe NPRM was prompted by EASA AD 2007-0256, dated September 19, 2007, issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for certain Pacific Scientific Company Seat Restraint System Plastic Rotary Buckle Handles. According to EASA, Pacific Scientific Company reported several instances of crackedhandles on certain buckles with a date of manufacture from November 2004 through May 2007. Testing on buckles with a cracked handle indicated that in some circumstances, a load placed on the restraint system prevents a strap from releasing as intended when the buckle is rotated. EASA states in its AD that this failure to release is possible when a passenger weighs more than 50 kg (approximately 110 lbs.) and an aircraft is upside down. \n\nComments \n\n\n\tAfter the SNPRM was published, the FAA received comments from two commenters. \n\nRequest for Credit \n\n\n\tNetJets QC requested that this AD allow credit for compliance with Cessna Citation Service Letter (SL) 560-25-09, Cessna Citation SL560XL- 25-10, or Cessna Citation SL750-25-15, each dated December 10, 2007. NetJets QC also requested that provisions be written in the AD for logbook/Illustrated Parts Catalog (IPC) research sign-off, since these buckles may not be installed on newly-manufactured aircraft. \n\tThe FAA disagrees withboth requests. This AD is an appliance AD that applies to Pacific Scientific Company buckles P/Ns 1111430 and 1111475, all dash numbers, without regard to date of manufacture, whereas each SL distinguishes the affected parts by date of manufacture. If an affected buckle is not installed on an aircraft, then this AD does not apply, and credit and provisions are not necessary to relieve this AD's requirements for the concerned aircraft. However, this AD does not prohibit using maintenance records to determine if an affected buckle is installed. Using an IPC is not an acceptable method to determine an aircraft's configuration. \n\nAddition of MU-2B Aircraft \n\n\n\tMitsubishi Heavy Industries America, Inc. (MHIA) suggested that the FAA add ''Mitsubishi MU-2B series aircraft'' to the list of aircraft models that could be affected by this AD. MHIA stated that Mitsubishi Heavy Industries, Ltd., holds Supplemental Type Certificate No. SA1751SW, which allows installation of certain affected buckles on Mitsubishi MU-2B series aircraft. \n\tThe FAA partially agrees. The FAA agrees that affected buckles could be installed on Mitsubishi Heavy Industries, Ltd., Model MU-2B series airplanes; however, the applicability only identifies possible installations on airplanes and helicopters by ''make'' and not ''models.'' Accordingly, the FAA has added Mitsubishi Heavy Industries, Ltd., to the list of airplanes that affected buckles could be installed on in the applicability of this final rule. \n\nExtension of Compliance Time \n\n\n\tMHIA requested extending the compliance time to at least 12 months, as replacement parts could be in short supply. MHIA states that it has attempted to contact the product support representative at Meggitt Services located in Simi Valley, CA in order to obtain additional technical information; however, no formal response had been received from Meggitt Services when MHIA submitted this comment on November 9, 2020. MHIA expressed concern that with limited support from Meggitt Services, owners and operators of affected airplanes will have difficulty meeting the compliance requirements because of a potential lack of sufficient replacement parts. \n\tThe FAA acknowledges MHIA's concern about contacting Meggitt Services and has re-confirmed that its contact information is accurate. The FAA disagrees with changing the compliance time to inspect an affected buckle handle for a crack from 6 months to 12 months based on a potential lack of sufficient replacement parts. The FAA has not received any information to indicate that there is an insufficient number of replacement parts that would necessitate extending the compliance time from that stated in the proposed AD. \n\nFAA's Determination \n\n\n\tThese products 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 thisAD after evaluating all of the information provided by EASA and determining the unsafe condition exists and is likely to exist or develop on other products and that air safety and the public interest require adopting the AD requirements as proposed with the changes described previously. These changes are consistent with the intent of the proposal in the SNPRM and will neither increase the economic burden on any operator nor increase the scope of this AD. \n\nDifferences Between This AD and the EASA AD \n\n\n\tThe EASA AD applies to certain buckles used on certain restraint systems that are known to be installed on, but not limited to, certain Eurocopter (now Airbus Helicopters) model helicopters. The applicability of the EASA AD is limited to rotorcraft only and is not intended for airplanes. Since the affected buckles may be installed in other aircraft resulting in the same unsafe condition, this AD applies to the same certain buckles, which may be installed on but not limited to certain airplanes and helicopters. This AD does not require returning the unairworthy buckle assembly to the manufacturer, and this AD does not apply to spare parts that are not installed on an aircraft. Also, this AD applies to buckle P/Ns 1111430 and 1111475, all dash numbers, and is not dependent on the restraint P/Ns. The EASA AD requires inspecting the buckles within 30 days, whereas this AD requires inspecting the buckle handle for a crack within 6 months and the buckle handle vane thickness within 12 months instead. The EASA AD requires a repetitive inspection of each buckle for cracks before any flight for up to 6 months following the effective date of the EASA AD until the buckle is replaced. This AD does not require an inspection for cracks before any flight for the 6 months until the affected buckles are replaced. The EASA AD identifies suspect parts by date of manufacture, and this AD does not. Finally, the EASA AD allows for marking a seat as ''un-operative'' and this AD doesnot. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed SB 25-1111432, which specifies inspecting each buckle P/Ns 1111430-XX and 1111475-XX with a date of manufacture between November 2004 and May 2007, to identify whether the handle is one susceptible to cracking by checking the P/N on the reverse side of the buckle assembly or by measuring the thickness of the handle vane. If the buckle is identified as a ''suspect'' buckle, this service information provides procedures for removing the buckle and replacing it with an acceptable buckle. Information in this service information also advises that buckles with a cracked handle should be removed from service immediately. \n\n((Page 17705)) \n\n\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\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD will affect 1,435 restraint systems installed on aircraft 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\tInspecting a buckle costs a minimal amount and takes a nominal amount of time. Replacing a buckle takes about 0.5 work-hour and parts cost about $636 for an estimated cost of $679 per buckle and up to $974,365 for the U.S. fleet. \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 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 theRegulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.