{"abstract":"We propose to adopt a new airworthiness directive (AD) for certain Bell Model 407 helicopters. This proposed AD would require installing a placard beneath the NR/NP dual tachometer and revising the limitations section of the rotorcraft flight manual (RFM). This proposed AD is prompted by several incidents of third stage engine turbine wheel failures, which were caused by excessive vibrations at certain engine speeds during steady-state operations. The proposed actions are intended to alert pilots to avoid certain engine speeds during steady-state operations, prevent failure of the third stage engine turbine, engine power loss, 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/2013/06/07/2013-13477.html","cfr_references":[{"chapter":null,"citation_url":null,"part":39,"title":14}],"citation":"78 FR 34286","comment_url":null,"comments_close_on":"2013-08-06","correction_of":null,"corrections":[],"dates":"We must receive comments on this proposed AD by August 6, 2013.","disposition_notes":null,"docket_ids":["Docket No. FAA-2013-0490","Directorate Identifier 2008-SW-004-AD"],"dockets":[],"document_number":"2013-13477","effective_on":null,"end_page":34288,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2013/06/07/2013-13477.xml","html_url":"https://www.federalregister.gov/documents/2013/06/07/2013-13477/airworthiness-directives-bell-helicopter-textron-canada-limited-bell-helicopters","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2013-13477?publication_date=2013-06-07","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2013-06-07/2013-13477/mods.xml","not_received_for_publication":null,"page_length":3,"page_views":{"count":81,"last_updated":"2026-08-24 02:15:07 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2013-06-07/pdf/2013-13477.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2013-13477.pdf?1370522904","publication_date":"2013-06-07","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2013/06/07/2013-13477.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 Attachments","document_id":"FAA-2013-0490-0004"},{"title":"U.S. DOT/FAA - See Attachments","document_id":"FAA-2013-0490-0002"}],"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-2013-0490","supporting_documents_count":2,"docket_id":"FAA-2013-0490","regulation_id_number":"2120-AA64","title":"2008-SW-004-AD Bell Helicopter Textron Canada, Ltd., Model 407, to require revising the limitations in the rotorcraft flight manual of steady-state operations and installing a placard.","checked_regulationsdotgov_at":"2013-06-27T08:06:34Z"},"regulations_dot_gov_url":null,"significant":false,"signing_date":null,"start_page":34286,"subtype":null,"title":"Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters","toc_doc":"Bell Helicopter Textron Canada Limited (Bell) Helicopters","toc_subject":"Airworthiness Directives:","topics":["Air transportation","Aircraft","Aviation safety","Incorporation by reference","Safety"],"type":"Proposed Rule","volume":78}