FAA-2025-15839

Document Headings Document headings vary by document type but may contain the following: • the agency or agencies that issued and signed a document • the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to • the agency docket number / agency internal file number • the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Department of Transportation Federal Aviation Administration • 14 CFR Part 39 • [Docket No. FAA-2024-2555; Project Identifier AD-2024-00214-R; Amendment 39-23089; AD 2025-15-02] • RIN 2120-AA64 ( printed page 40529) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain Siam Hiller Holdings, Inc. (Siam Hiller), Model UH-12E (Army OH-23G and H-23F) and UH-12E-L helicopters. This AD was prompted by reports of cracks found in a main rotor (M/R) transmission drive shaft (drive shaft). This AD requires inspecting certain M/R drive shafts for a crack, prohibits installing certain M/R drive shafts unless the inspection is done, and prohibits using certain paint strippers. The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective September 24, 2025. ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2024-2555; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Eduardo Orozco-Duran, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: (562) 627-5264; email: eduardo.orozco-duran@faa.gov. SUPPLEMENTARY INFORMATION: Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Siam Hiller Model UH-12E (Army OH-23G and H-23F) and UH-12E-L helicopters. The NPRM was published in the Federal Register on January 14, 2025 (90 FR 03046). The NPRM was prompted by reports of two cracks in an M/R drive shaft that were found during an inspection involving a Siam Hiller Model UH-12E helicopter. In the NPRM, the FAA proposed to require inspecting certain M/R drive shafts for a crack, prohibit installing certain M/R drive shafts unless the inspection is done, and prohibit using certain paint strippers. The FAA is issuing this AD to address non-conforming parts and the use of improper paint stripper; and to detect cracking of the M/R drive shaft. The unsafe condition, if not addressed, could result in separation of the M/R drive shaft and M/R blades from the helicopter and consequent loss of control of the helicopter. Discussion of Final Airworthiness Directive Comments The FAA received comments from Summit Helicopters, Inc (Summit Helicopters). The following presents the comments received on the NPRM and the FAA's response to each comment. Request To Extend Compliance Times Summit Helicopters stated the compliance time proposed in the NPRM would create significant economic impact for their company and is requesting an additional time margin to be added for the required inspections. The commenter stated that the time required to perform these inspections, as proposed in the NPRM, is significantly short of the actual time it would take to perform these i…

Fonte: Federal Register (federalregister.gov). Texto original em inglês. Conteúdo sanitizado por segurança.