{"id":"F2006B05748","name":"AD/PA-31/43 - Alternate Air Door Magnetic Catch - Replacement/Modification","slug":"ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135583,"registerId":"commonwealth-F2006B05748-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/43 - Alternate Air Door Magnetic Catch - Replacement/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)  Piper PA-31 Series Aeroplanes\n\n \n\nAD/PA-31/43 Alternate Air Door Magnetic Catch -\n\nReplacement/Modification\n\n\n5/76\n\n \n\nApplicability: Model PA-31-325 with S/Nos. 31-7400990 and 31-7512006 to 31-7612030. Model PA-31-350 with S/Nos. 31-5001 to 31-7652066.\n\n \n\nDocument: Piper SB No. 479B. Compliance: Before 1 August 1976.\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\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 \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1488},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope targeting a specific mechanical defect in specific aircraft. No expansion beyond the original airworthiness safety purpose is evident."},"complexity_factors":["Narrow applicability limited to specific serial numbers of two aircraft models","Single, unambiguous maintenance action with no exceptions or conditional provisions","Relies on external technical document (Service Bulletin 479B) for implementation details rather than prescribing complex procedures within the text itself"],"plain_english_summary":"This Airworthiness Directive mandates a safety fix for specific Piper PA-31 aircraft (Navajo models). **What it requires:** Owners must replace or modify the magnetic catches on the *alternate air doors* (backup air intakes that open if the main engine air supply gets blocked) following the manufacturer's instructions in Piper Service Bulletin No. 479B. **Which planes are affected:** Only specific serial numbers of the PA-31-325 and PA-31-350 models built in the mid-1970s. **Why it matters:** Defective magnetic catches could allow these doors to open unexpectedly or fail to seal properly, risking loss of engine power if ice or debris blocks the main air intake. **Deadline:** The modification had to be completed before 1 August 1976. While this directive is historical, it remains enforceable until compliance is recorded in the aircraft's maintenance logs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification","history":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification/history","analysis":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification/analysis","conflicts":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification/conflicts","importantCases":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification/important-cases","documents":"/api/acts/ad-pa-31-43-alternate-air-door-magnetic-catch-replacement-modification/documents"}}