{"abstract":"The FAA is revising an earlier proposed airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. The original NPRM would have required replacing the aero/fire seals of the blocker doors on the thrust reverser torque boxes on the engines with new, improved aero/fire seals. The original NPRM resulted from a report that the top three inches of the aero/fire seals of the blocker doors on the thrust reverser torque boxes are not fireproof. This action revises the original NPRM by adding airplanes to the applicability statement and requiring a one-time inspection to determine the part numbers of the aero/fire seals. We are proposing this supplemental NPRM to prevent a fire in the fan compartment (a fire zone) from migrating through the seal to a flammable fluid in the thrust reverser actuator compartment (a flammable fluid leakage zone), which could result in an uncontrolled fire.","action":"Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.","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/2008/09/03/E8-20341.html","cfr_references":[{"chapter":null,"citation_url":null,"part":39,"title":14}],"citation":"73 FR 51382","comment_url":null,"comments_close_on":"2008-09-29","correction_of":null,"corrections":[],"dates":"We must receive comments on this supplemental NPRM by September 29, 2008.","disposition_notes":null,"docket_ids":["Docket No. FAA-2006-25001","Directorate Identifier 2006-NM-079-AD"],"dockets":[],"document_number":"E8-20341","effective_on":null,"end_page":51384,"executive_order_notes":null,"executive_order_number":null,"explanation":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2008/09/03/E8-20341.xml","html_url":"https://www.federalregister.gov/documents/2008/09/03/E8-20341/airworthiness-directives-boeing-model-737-600--700--700c--800--900-and--900er-series-airplanes","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/E8-20341?publication_date=2008-09-03","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2008-09-03/E8-20341/mods.xml","not_received_for_publication":null,"page_length":3,"page_views":{"count":12,"last_updated":"2026-04-04 10:15:04 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2008-09-03/pdf/E8-20341.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":null,"publication_date":"2008-09-03","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2008/09/03/E8-20341.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-2006-25001-0023"},{"title":"U.S DOT/FAA - See Attachment","document_id":"FAA-2006-25001-0019"},{"title":"U.S DOT/FAA - See Attachments","document_id":"FAA-2006-25001-0018"},{"title":"Attached","document_id":"FAA-2006-25001-0013"},{"title":"U.S. DOT/FAA - Airworthiness Directive Grid","document_id":"FAA-2006-25001-0010"},{"title":"U.S. DOT/FAA - Regulatory Evaluation","document_id":"FAA-2006-25001-0005"},{"title":"U.S. DOT/FAA - Airworthiness Directive Grid","document_id":"FAA-2006-25001-0004"}],"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-2006-25001","supporting_documents_count":7,"docket_id":"FAA-2006-25001","regulation_id_number":"2120-AA64","title":"2006-NM-079-AD","checked_regulationsdotgov_at":"2011-11-14T17:24:02Z"},"regulations_dot_gov_url":null,"significant":false,"signing_date":null,"start_page":51382,"subtype":null,"title":"Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, -900 and -900ER Series Airplanes","toc_doc":"Boeing Model 737-600, -700, -700C, -800, -900 and  900ER Series Airplanes","toc_subject":"Airworthiness Directives:","topics":["Air transportation","Aircraft","Aviation safety","Safety"],"type":"Proposed Rule","volume":73}