{"abstract":"The FAA proposes to adopt a new airworthiness directive (AD) for Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters. This proposed AD was prompted by the discovery that certain parts that are approved for installation on multiple helicopter models are life limited parts when installed on Model MBB-BK 117 D-2 helicopters and some helicopter delivery documents excluded the life limit information. This proposed AD would require determining the total hours time-in-service (TIS) of a certain part-numbered rotor mast nut and re-identifying a certain part-numbered rotor mast nut. This proposed AD would also require establishing a life limit for a certain part-numbered rotor mast nut and helical gear support, and removing each part from service before reaching its life limit. Additionally, this proposed AD would require replacing a certain part-numbered main gearbox (MGB) with a not affected MGB as specified in a European Aviation Safety Agency (now European Union Aviation Safety Agency) (EASA) AD, which is proposed for incorporation by reference (IBR). The FAA is proposing this AD to address the unsafe condition on these products.","action":"Notice of proposed rulemaking (NPRM).","agencies":[{"raw_name":"DEPARTMENT OF TRANSPORTATION","name":"Transportation Department","id":492,"url":"https://www.federalregister.gov/agencies/transportation-department","json_url":"https://www.federalregister.gov/api/v1/agencies/492","parent_id":null,"slug":"transportation-department"},{"raw_name":"Federal Aviation Administration","name":"Federal Aviation Administration","id":159,"url":"https://www.federalregister.gov/agencies/federal-aviation-administration","json_url":"https://www.federalregister.gov/api/v1/agencies/159","parent_id":492,"slug":"federal-aviation-administration"}],"body_html_url":"https://www.federalregister.gov/documents/full_text/html/2021/06/07/2021-11804.html","cfr_references":[{"chapter":null,"citation_url":null,"part":39,"title":14}],"citation":"86 FR 30218","comment_url":null,"comments_close_on":"2021-07-22","correction_of":null,"corrections":[],"dates":"The FAA must receive comments on this proposed AD by July 22, 2021.","disposition_notes":null,"docket_ids":["Docket No. FAA-2021-0450","Project Identifier 2017-SW-100-AD"],"dockets":[{"supporting_documents":[{"title":"Supporting AD Documents","document_id":"FAA-2021-0450-0005"},{"title":"Supporting AD Document","document_id":"FAA-2021-0450-0003"}],"agency_name":"FAA","documents":[{"comment_count":1,"comment_start_date":"2021-06-07","updated_at":"2023-02-28T20:24:00.871-05:00","comment_url":"https://www.regulations.gov/commenton/FAA-2021-0450-0001","allow_late_comments":null,"id":"FAA-2021-0450-0001","comment_end_date":"2021-07-23","regulations_dot_gov_open_for_comment":false}],"supporting_documents_count":2,"id":"FAA-2021-0450","title":"Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters.  Life limited parts"}],"document_number":"2021-11804","effective_on":null,"end_page":30221,"executive_order_notes":null,"executive_order_number":null,"explanation":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2021/06/07/2021-11804.xml","html_url":"https://www.federalregister.gov/documents/2021/06/07/2021-11804/airworthiness-directives-airbus-helicopters-deutschland-gmbh-ahd-helicopters","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2021-11804?publication_date=2021-06-07","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2021-06-07/2021-11804/mods.xml","not_received_for_publication":null,"page_length":4,"page_views":{"count":172,"last_updated":"2026-04-04 10:15:04 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2021-06-07/pdf/2021-11804.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2021-11804.pdf?1622810733","publication_date":"2021-06-07","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2021/06/07/2021-11804.txt","regulation_id_number_info":{"2120-AA64":{"issue":"202410","html_url":"https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives","title":"Airworthiness Directives","xml_url":"http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202410&RIN=2120-AA64&operation=OPERATION_EXPORT_XML","priority_category":"Routine and Frequent"}},"regulation_id_numbers":["2120-AA64"],"regulations_dot_gov_info":{"supporting_documents":[{"title":"Supporting AD Documents","document_id":"FAA-2021-0450-0005"},{"title":"Supporting AD Document","document_id":"FAA-2021-0450-0003"}],"regulatory_plan":{"html_url":"https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives","title":"Airworthiness Directives"},"comments_count":1,"agency_id":"FAA","comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=FAA-2021-0450","supporting_documents_count":2,"docket_id":"FAA-2021-0450","document_id":"FAA-2021-0450-0001","regulation_id_number":"2120-AA64","title":"Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters.  Life limited parts","checked_regulationsdotgov_at":"2023-03-01T01:23:59Z"},"regulations_dot_gov_url":null,"significant":false,"signing_date":null,"start_page":30218,"subtype":null,"title":"Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters","toc_doc":"Airbus Helicopters Deutschland GmbH (AHD) Helicopters","toc_subject":"Airworthiness Directives;\n","topics":["Air transportation","Aircraft","Aviation safety","Incorporation by reference","Safety"],"type":"Proposed Rule","volume":86}