Discussion \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to remove AD 2016-02-06, Amendment 39-18387 (81 FR 5367, February 2, 2016) (''AD 2016-02-06'') and add a new AD. AD 2016-02-06 applied to Bell Model 429 helicopters with a T/R link part number (P/N) 429-012-112-101, -101FM, -103, or -103FM installed. The NPRM published in the Federal Register on August 20, 2019 (84 FR 43085). Since the FAA issued AD 2016-02-06, improved T/R links P/N 429-012-112-111 and -113 were developed, but recurring inspections of the sealant of these T/R links are still necessary because they are subject to the same unsafe condition due to design similarity. Some T/R links P/N 429-012-112-101 and -103 have also been field modified and re-identified as T/R links P/N 429-012-112-111FM and -113FM, and continue to need recurring inspections of the sealant as they are also subject to the same unsafe condition due to design similarity. \n\tThe NPRM proposed to continue the requirements of AD 2016-02-06 and add P/Ns 429-012-112-111, -111FM, -113, and -113FM to the applicability. The NPRM also proposed to add use of 10X or higher power magnification to the visual inspection of each cleaned T/R link for pitting and a repetitive 12-month inspection with the corrosion preventative sealant removed. \n\tTransport Canada, which is the aviation authority for Canada, issued AD No. CF-2016-01R2, dated April 12, 2017 (AD CF-2016-01R2) to clarify the applicable P/Ns, address spare parts, and address parts installed on-condition prior to December 7, 2015. AD CF-2016-01R2 also includes a terminating action for the repetitive inspections. \n\nComments \n\n\n\tAfter the NPRM was published, the FAA received comments from one commenter. \n\nRequest \n\n\n\tBell Textron, Inc., commented that this AD omits Bell Helicopter Alert Service Bulletin (ASB) 429-15-16 Rev. B, dated June 15, 2016 (ASB 429-15-16 Rev. B), which was issued after Bell HelicopterASB 429-15- 26, dated December 7, 2015 (ASB 429-15-26). The FAA acknowledges that ASB 429-15-16 Rev. B and ASB 429-15-26 specify procedures for the same part-numbered T/R links. However, the two service information documents address different unsafe conditions, specifically ASB 429-15-16 Rev. B addresses wear and ASB 429-15-26 addresses corrosion. Accordingly, the two different unsafe conditions are addressed in two separate ADs. The unsafe condition of wear (ASB 429-15-16 Rev. B) is addressed in AD 2019-11-05, Amendment 39-19651 (84 FR 26546, June 7, 2019) (''AD 2019- 11-05''). The unsafe condition of corrosion (ASB 429-15-26) is addressed in this AD. The FAA did not change this AD based on this comment. \n\tBell Textron, Inc., commented that this AD differs from ASB 429-15- 16 Rev. B and ASB 429-15-26 by requiring removal of the sealant around the bearing every 12 months and an inspection of the chamfer with a 10X magnifying lens. Bell Textron, Inc., stated that since ASB 429-15-16 Rev. B ''requires'' a repetitive 50 flight hours inspection of the sealant for pin holes and voids, it does not feel the repetitive 12 month inspection with the sealant removed is necessary. The FAA disagrees. Procedures specified in related service information documents are not required unless mandated by an AD. And while AD 2019- 11-05 mandates the repetitive inspection of the sealant condition for pin holes and voids specified in ASB 429-15-16 Rev. B, the FAA determined an inspection with the sealant removed at a longer-term repetitive interval is necessary. Since sealant could become damaged, not maintain seal, or become worn, this more in-depth inspection addresses corrosion and pitting that could build up underneath the sealant. The FAA did not change this AD based on this comment. \n\tBell Textron, Inc., commented that not requiring part re- identification makes it more complicated to manage configurations. The FAA does not prohibit re-identifying the T/R links as specified in ASB429-15-26; however, the FAA determined it unnecessary to require to address the unsafe condition since the repetitive inspections are required for all part-numbered links listed in the applicability. The FAA did not change this AD based on this comment. \n\nFAA's Determination \n\n\n\tThe FAA has reviewed the relevant information and determined that an unsafe condition exists and is likely to exist or develop on other helicopters of the same type design and that air safety and the public interest require adopting the AD requirements as proposed except for editorial changes. The website URL for Bell and the email address for requesting an alternative method of compliance have changed and have been updated in this final rule. Additionally, the paragraph cross- referencing formatting in the Required Actions paragraph has changed to meet current publication requirements, e.g., ''(f)(3)(i) and (f)(3)(ii)'' has changed to ''(f)(3)(i) and (ii)'' instead. These editorial changes are consistentwith the intent of the proposals in the NPRM and will not increase the economic burden on any operator nor increase the scope of the AD. \n\nInterim Action \n\n\n\tThe FAA considers this AD to be an interim action. The design approval holder is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA might consider additional rulemaking. \n\nDifferences Between This AD and the Transport Canada AD \n\n\n\tThis AD applies to helicopters with certain link P/Ns installed, whereas the Transport Canada AD applies to helicopters with certain serial numbers instead. This AD requires inspecting the bearing bores for any pitting after cleaning the T/R link, while the Transport Canada AD requires inspecting for corrosion after cleaning the T/R link. This AD requires performing the inspections with 10X or higher magnification, while the Transport Canada AD does not specify any magnification. This AD does not require re-identifying the P/N of the \n\n((Page 49943)) \n\nlink, whereas the Transport Canada AD does. The Transport Canada AD also provides a terminating action to the repetitive sealant inspection, while this AD does not. This AD also requires a repetitive inspection with the corrosion preventative sealant removed and reapplied, whereas the Transport Canada AD does not. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed ASB 429-15-26, which advises of reports of corrosion on T/R links between the roll staked lip of bearing P/N 429- 312-107-103 and the beveled edge of T/R link P/Ns 429-012-112-101/-103. ASB 429-15-26 specifies inspecting each T/R link bearing bore between the roll staked lip of the bearing outer race and the link bearing bore with 10X magnification for corrosion and if there is corrosion, replacing the link. If there is no corrosion, ASB 429-15-26 specifies cleaning the area and performing a second inspection with 10X magnification for corrosion. If there is corrosion, ASB 429-15-26 specifies replacing the link. If there is no corrosion, ASB 429-15-26 specifies removing the torque stripe, cleaning the area, and applying corrosion preventative sealant. ASB 429-15-26 also specifies re- identifying the P/Ns as 429-012-112-101FM/-103FM. Further, ASB 429-15- 26 specifies a repetitive inspection of the sealant and reapplication if the sealant is damaged. \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 affects 93 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 the set of T/R links (eight bearings) for corrosion takes about one work-hour for an estimated cost of $85 per helicopter and $7,905 for the U.S. fleet per inspection cycle. Cleaning and inspecting the set of T/R links for pitting takes about one work-hour for an estimated cost of $85 per helicopter. Replacing a T/R link requires no additional work-hours after the inspection and required parts cost $2,739 for an estimated replacement cost of $2,739 per T/R link. Removing the torque stripe, cleaning, and applying sealant to the set of T/R links takes about one work-hour with a negligible parts cost for an estimated cost of $85 per helicopter. Inspecting the sealant on a set of T/R links takes about one work-hour for an estimated cost of $85 per helicopter and $7,905 for the U.S. fleet per inspection cycle. \n\tAccording to Bell Helicopter's 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 Bell Helicopter. Accordingly, the FAA has included all costs in this costestimate. \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\tThe FAA has determined that this AD will not have federalism implications under ExecutiveOrder 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.