{"id":"F2006B05559","name":"AD/PA-25/21 Amdt 3 - Top Longeron - Modification","slug":"ad-pa-25-21-amdt-3-top-longeron-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46536,"registerId":"commonwealth-F2006B05559-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-25/21 Amdt 3 - Top Longeron - 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-25 (Pawnee) Series Aeroplanes\n\n \n\nAD/PA-25/21\n\nAmdt 3\n\n\nTop Longeron - Modification 8/71\n\n \n\nApplicability: Model PA-25-235 and variants of that model prior to S/No. 25-3732 not incorporating Piper Kit No. 756987 or not modified in accordance with a schedule approved by the Secretary.\n\n \n\nDocument: Piper SB No. 341.\n\n \n\nCompliance: For aircraft with less than 1000 hours total time in service - before achieving 1000 hours time in service.\n\n \n\nFor aircraft with more than 1000 hours time in service as at 31 August 1971 - within 100 hours time in service after 31 Aug. 1971.\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":1520},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow technical scope concerning a specific structural modification for designated Piper aircraft. Amendment 3 appears to be an administrative or minor technical update rather than an expansion of scope beyond the original airworthiness safety intent."},"complexity_factors":["Single technical modification requirement with clear reference to manufacturer service bulletin","Binary applicability test based on aircraft serial number and kit installation status","Simple two-path compliance structure based on accumulated flight hours","No nested definitions, exceptions to exceptions, or cross-references to other legislative instruments"],"plain_english_summary":"Owners of Piper PA-25 Pawnee (PA-25-235 and variants, serials before 25-3732) must modify the top longeron per Piper Service Bulletin No. 341, unless Kit No. 756987 or an approved alternate modification is already installed. Compliance timing: before the airplane reaches 1,000 total hours if under 1,000 now, or within 100 flight hours after 31 Aug 1971 if it already exceeded 1,000 hours. The change prevents longeron failure that could cause loss of control and crashes."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification","history":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification/history","analysis":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification/analysis","conflicts":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification/conflicts","importantCases":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification/important-cases","documents":"/api/acts/ad-pa-25-21-amdt-3-top-longeron-modification/documents"}}