{"id":"F2006B09115","name":"AD/DHC-6/28 - Engine Compressor Inlet Screens - Icing Restrictions","slug":"ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115668,"registerId":"commonwealth-F2006B09115-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/28 - Engine Compressor Inlet Screens - Icing Restrictions","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)  DHC-6 (Twin Otter) Series Aeroplanes\n\n \n\nAD/DHC-6/28  Engine Compressor Inlet Screens - Icing Restrictions\n\n\n8/71\n\n \n\nApplicability: All models with PT6-20 and -27 engines using fine mesh engine compressor inlet screens.\n\n \n\nDocument: De Havilland Aircraft of Canada SB No. 6/282. Compliance: Before 1 September 1971.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1754},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"The directive remains tightly focused on its original purpose: addressing icing risks on specific engine inlet screens for the DHC-6 aircraft type. There is no evidence of scope expansion beyond this specific technical safety issue."},"complexity_factors":["Extremely short text (less than 100 words of operative provisions)","Single, clear applicability criterion (specific engine models with specific screens)","Only one compliance action required (follow the referenced service bulletin)","No definitions section, no cross-references to other legislation, and no exceptions or conditional clauses"],"plain_english_summary":"This Airworthiness Directive (AD) is a safety rule requiring specific action on De Havilland DHC-6 (Twin Otter) aircraft engines to prevent dangerous icing conditions.\n\n**What it requires:**\nOperators must comply with **De Havilland Service Bulletin No. 6/282** regarding the engine compressor inlet screens.\n\n**Who is affected:**\nOwners and operators of DHC-6 aircraft fitted with **PT6-20 or PT6-27 engines** that use **fine mesh engine compressor inlet screens**.\n\n**Why it matters:**\nThe fine mesh screens can be susceptible to ice accumulation, which restricts airflow to the engine compressor and could cause engine failure or reduced performance.\n\n**Compliance deadline:**\nAircraft must meet these requirements before 1 September 1971."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions","history":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions/history","analysis":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions/analysis","conflicts":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions/conflicts","importantCases":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions/important-cases","documents":"/api/acts/ad-dhc-6-28-engine-compressor-inlet-screens-icing-restrictions/documents"}}