{"id":"F2006B09141","name":"AD/DHC-6/52 - Windscreen Washer/De-Icing System - Discontinued Use of Isopropyl Alcohol","slug":"ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115701,"registerId":"commonwealth-F2006B09141-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/52 - Windscreen Washer/De-Icing System - Discontinued Use of Isopropyl Alcohol","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nDHC-6 (Twin Otter) Series Aeroplanes\n\nAD/DHC-6/52 Windscreen Washer/De-Icing System \\-\n\nDiscontinued Use of Isopropyl Alcohol\n\n  \n10/82\n\nApplicability: All DHC-6 aircraft incorporating windscreen washer/ de-icing system using isopropyl alcohol.\n\nRequirement: 1. The use of 50/50 mixture or 100 percent isopropyl alcohol to be discontinued for the windscreen washer/de-icing system.\n\n    2. Only proprietary type fluids such as those specified in De Havilland of Canada SB 6/422, or as otherwise approved by the Department of Aviation shall be used.\n\n    3. Removal of label located above windscreen washer/de-icing system reservoir which indicates filling requirements using isopropyl alcohol.\n\nNote: Canadian Airworthiness Directive No. CF-82-20 refers.\n\nEffective: Forthwith.\n\nBackground: An in-flight fire may have been caused by a faulty connection in the windscreen washer/de-icing system which allowed isopropyl alcohol to escape into the flight compartment area.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific fire hazard in a specific aircraft type. It has not expanded beyond its original purpose of banning isopropyl alcohol use in DHC-6 windscreen systems."},"complexity_factors":["Very short document (under 200 words)","Only 3 simple, unnumbered requirements with no sub-paragraphs","No defined terms section","No cross-references to other legislation (only references a Canadian AD and a manufacturer service bulletin for context)","No conditional logic or exceptions","Single, clear applicability criterion"],"plain_english_summary":"This AD immediately prohibits using isopropyl alcohol in windscreen washer and de-icing systems on DHC‑6 Twin Otter aircraft, requires replacement with approved commercial fluids per the De Havilland service bulletin or Department approval, and mandates removal of any labels directing use of isopropyl alcohol.  \n\nIt affects Twin Otter owners, operators, and maintenance personnel — issued because leaks of flammable isopropyl alcohol into the cockpit create a serious in‑flight fire risk."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The directive removes prior permissive use of isopropyl alcohol for affected DHC‑6 washer/de‑icing systems and replaces it with a requirement to use approved proprietary fluids (per De Havilland SB 6/422 or Department of Aviation approval). Operators bear the costs of replacing fluids and removing labels, and the Department of Aviation controls approval of any alternatives (Requirements 1–3)."},"complexity_factors":["Applicability is narrow but absolute: applies to all DHC-6 aircraft with washer/de-icing systems using isopropyl alcohol (Applicability).","Immediate compliance: directive effective 'Forthwith' increases operational haste and shortens time for sourcing alternatives (Effective: Forthwith).","Regulatory substitution: bans 50/50 and 100% isopropyl alcohol and requires 'proprietary' fluids per De Havilland SB 6/422 or Department of Aviation approval, introducing an approval gate and potential procurement friction (Requirement 1–2).","Label change: requires physical removal of existing fill-direction label, a simple but mandatory maintenance action (Requirement 3).","Administrative discretion: Department of Aviation approval for alternative fluids creates a centralised decision point and possible processing delay (Requirement 2).","Traceable safety rationale: links to in-flight fire risk from escaped alcohol, anchoring the mandate to a specific hazard and a foreign AD reference (Background; Note)."],"plain_english_summary":"This airworthiness directive stops use of 50/50 or 100% isopropyl alcohol in windscreen washer/de‑icing systems on all DHC‑6 (Twin Otter) aeroplanes, requires approved proprietary fluids instead, and mandates removal of any isopropyl‑filling label. The regulator says the change responds to a possible in‑flight fire caused by alcohol leakage; operators and maintenance organisations must source approved fluids (De Havilland SB 6/422 or Department of Aviation approval), update labeling, and alter maintenance practice, creating procurement and compliance costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol","history":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol/history","analysis":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol/analysis","conflicts":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol/conflicts","importantCases":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol/important-cases","documents":"/api/acts/ad-dhc-6-52-windscreen-washer-de-icing-system-discontinued-use-of-isopropyl-alcohol/documents"}}