{"abstract":"We propose to adopt a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model AB139 and AW139 helicopters with a certain generator control unit (GCU). This proposed AD was prompted by laboratory tests which revealed a potential fault in the overvoltage protection on a certain part-numbered GCU. This proposed AD would require replacing each affected GCU with an airworthy GCU. In addition, any affected GCU is not approved for installation on any helicopter. We are proposing this AD to prevent failure of the overvoltage protection of the GCU, degraded performance of the electrical power generation and distribution systems, a fire, and subsequent loss of control of the helicopter.","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/2012/01/20/2012-1121.html","cfr_references":[{"chapter":null,"citation_url":null,"part":39,"title":14}],"citation":"77 FR 2926","comment_url":"http://www.regulations.gov/commenton/FAA-2012-0013-0001","comments_close_on":"2012-03-20","correction_of":null,"corrections":[],"dates":"We must receive comments on this proposed AD by March 20, 2012.","disposition_notes":null,"docket_ids":["Docket No. FAA-2012-0013","Directorate Identifier 2010-SW-043-AD"],"dockets":[],"document_number":"2012-1121","effective_on":null,"end_page":2928,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2012/01/20/2012-1121.xml","html_url":"https://www.federalregister.gov/documents/2012/01/20/2012-1121/airworthiness-directives-agusta-spa-helicopters","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2012-1121?publication_date=2012-01-20","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2012-01-20/2012-1121/mods.xml","not_received_for_publication":null,"page_length":3,"page_views":{"count":60,"last_updated":"2026-09-22 18:15:08 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2012-01-20/pdf/2012-1121.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2012-01121.pdf?1326980956","publication_date":"2012-01-20","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2012/01/20/2012-1121.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":"U.S. DOT/FAA - See Attachment","document_id":"FAA-2012-0013-0006"},{"title":"U.S./DOT/FAA - Additional Information - Disposition of Comments Form (no comments received)","document_id":"FAA-2012-0013-0004"},{"title":"U.S. DOT/FAA - See Attachments","document_id":"FAA-2012-0013-0002"}],"regulatory_plan":{"html_url":"https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives","title":"Airworthiness Directives"},"comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=FAA-2012-0013","supporting_documents_count":3,"docket_id":"FAA-2012-0013","regulation_id_number":"2120-AA64","title":"2010-SW-043-AD Agusta S.p.A. ModelAB139 and AW139 Helicopters","checked_regulationsdotgov_at":"2023-03-01T18:07:28Z"},"regulations_dot_gov_url":"http://www.regulations.gov/commenton/FAA-2012-0013-0001","significant":false,"signing_date":null,"start_page":2926,"subtype":null,"title":"Airworthiness Directives; Agusta S.p.A. Helicopters","toc_doc":"Agusta S.p.A. Helicopters","toc_subject":"Airworthiness Directives:","topics":["Air transportation","Aircraft","Aviation safety","Incorporation by reference","Safety"],"type":"Proposed Rule","volume":77}