{"id":"F2006B04232","name":"AD/BEECH 90/41 - Cabin Heater Modification and Aft Fuselage Drainage and Sealing - Modification","slug":"ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43993,"registerId":"commonwealth-F2006B04232-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 90/41 - Cabin Heater Modification and Aft Fuselage Drainage and Sealing - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Beechcraft 90 and 65-90 (King Air) Series Aeroplanes\n\n \n\n# AD/BEECH 90/41 Cabin Heater Modification and Aft Fuselage\n\nDrainage and Sealing - Modification\n\nApplicability: Models 65-90, 65-A90 & B90 with S/Nos. LJ-1 to LJ-484. Requirement:  1. Install a temporary placard on the heater control panel stating:\n\n“IF HEATER FAILS TO HEAT, TURN OFF IMMEDIATELY”\n\n# 2/76\n\n \n\n2.    Modify cabin heater installation, including the fitment of a cabin heater out light, in accordance with Beechcraft SI No. 0230-412, Revision 3.\n\n \n\n3.    Modify the aft fuselage in accordance with Beechcraft SI No. 0268-103, Rev. 1. Compliance:              For Para. 1 - Within 50 hours’ time in service after 27 Feb. 1976.\n\nFor Para. 2 - Before 1 January 1977.\n\n \n\nFor Para. 3 - Within 100 hours’ time in service after 27 Feb. 1976.\n\n \n\nNote: Temporary placard, para. 1, may be removed when para. 2 is accomplished.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive as presented sets requirements for the specified Beechcraft models/SNs and prescribes three modification actions with deadlines. The text does not indicate any change from an earlier or different scope within this instrument; it defines applicability and remedial measures without showing expansion or narrowing beyond those terms."},"complexity_factors":["Multiple discrete requirements with separate compliance deadlines (Para.1–3).","Mixed deadline types: hours-in-service after 27 Feb 1976 for Para.1 and Para.3, and a fixed calendar deadline for Para.2.","Applicability limited to specific serial numbers (Models 65‑90, 65‑A90 & B90, S/N LJ‑1 to LJ‑484) which narrows affected operators.","Relies on external Beechcraft Service Instructions for the technical work (SI No. 0230‑412 Rev.3 and SI No. 0268‑103 Rev.1).","Requires physical aircraft modifications (heater installation changes and aft fuselage drainage/sealing) which impose maintenance scheduling and workshop capability constraints.","Temporary placard condition linked to completion of a later modification (removal permitted when Para.2 accomplished)."],"plain_english_summary":"This airworthiness directive requires owners/operators of Beechcraft 65‑90, 65‑A90 and B90 aeroplanes (S/N LJ‑1 to LJ‑484) to fit a temporary heater‑failure placard, modify the cabin heater (including a heater‑out light) per Beechcraft SI No. 0230‑412 Rev.3, and modify aft fuselage drainage and sealing per SI No. 0268‑103 Rev.1. Owners/operators must arrange and fund these modifications within the specified time‑in‑service deadlines; the placard may be removed once the heater modification is completed (Para.1–3)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose Airworthiness Directive focused on specific safety modifications to a limited range of aircraft. It has not expanded beyond its original technical safety purpose."},"complexity_factors":["Very short document (approximately 200 words)","Only 3 defined requirements with clear, specific compliance deadlines","Minimal cross-referencing (only references to 2 external Beechcraft Service Instructions)","Simple conditional logic (temporary placard can be removed when permanent fix is installed)","Narrow applicability (specific aircraft models and serial number range)","No nested exceptions or complex definitional sections"],"plain_english_summary":"Owners/operators of Beechcraft King Air 90 series (serials LJ-1 to LJ-484) must comply with an urgent CASA Airworthiness Directive requiring temporary and permanent fixes to the cabin heater system (including a “heater out” warning) and sealing/modification of the aft fuselage. It addresses heater fire/smoke risks and aft drainage/sealing defects; compliance is mandatory to keep the aircraft legal to fly."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification","history":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification/history","analysis":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification/analysis","conflicts":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification/conflicts","importantCases":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification/important-cases","documents":"/api/acts/ad-beech-90-41-cabin-heater-modification-and-aft-fuselage-drainage-and-sealing-modification/documents"}}