{"id":"F2006B02090","name":"AD/AC/30 - Replacement of Fuel System Aluminium Drain Tubing and Fittings and Wing Trailing Edge - Modification","slug":"ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41320,"registerId":"commonwealth-F2006B02090-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC/30 - Replacement of Fuel System Aluminium Drain Tubing and Fittings and Wing Trailing Edge - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue NK,Aircraft below 5700 kg,Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes,Replacement of Fuel System Aluminium Drain Tubing and Fittings and Wing Trailing Edge - Modification,30\ntitle: Airworthiness Directive - AD/AC/30 - Replacement of Fuel System Aluminium Drain Tubing and Fittings and Wing Trailing Edge - Modification\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)  Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes\n\n \n\nAD/AC/30 Replacement of Fuel System Aluminium NK\n\nDrain Tubing and Fittings and Wing Trailing Edge - Modification\n\nApplicability: Models 520 and 560: S/Nos. 1 to 230. Document:  1. Aero Commander SBs No. 77 and 79; or\n\n2. FAA AD 62-8-2.\n\n \n\nCompliance: Forthwith.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text presents a targeted, mandatory replacement/modification for specified aircraft; there is no indication within this instrument that its scope has been changed from an earlier intent or version."},"complexity_factors":["Narrow applicability (specific models and serial number range) reduces scope complexity","Relies on external technical documents (Aero Commander SBs No. 77 and 79, FAA AD 62‑8‑2) for procedural detail","Immediate compliance requirement ('Forthwith') creates operational urgency for affected operators","Instrument is concise and prescriptive, with no procedural variance or discretionary exemptions in the text","Regulatory basis under Civil Aviation Regulations Part 39 adds enforcement and certification implications"],"plain_english_summary":"Requires replacement of aluminium fuel-system drain tubing and fittings and a modification to the wing trailing edge on Twin Commander Models 520 and 560 (serial numbers 1–230). Operators must carry out the work immediately, following Aero Commander Service Bulletins No. 77 and 79 or FAA AD 62‑8‑2. This affects owners and operators of the specified aeroplanes and matters because it imposes an immediate, mandatory maintenance action tied to airworthiness under CASA Part 39."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This appears to be a historical Airworthiness Directive (reference 'NK' suggests an older numbering system). The scope remains tightly focused on the specific safety issue it was designed to address — fuel system aluminium drain tubing replacement on specific early-model Twin Commander aircraft. There is no evidence of scope creep; the directive maintains its original narrow applicability to models 520 and 560, serial numbers 1-230 only."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (model numbers and serial number range)","Simple binary compliance structure (follow either document 1 OR document 2)","No nested exceptions or conditional logic","Single, unambiguous compliance deadline ('Forthwith')","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Straightforward applicability section with clear serial number cut-off"],"plain_english_summary":"Australia's Civil Aviation Safety Authority has issued a mandatory Airworthiness Directive requiring immediate replacement of aluminium fuel drain tubing/fittings and a wing trailing-edge modification on early Twin Commander 520/560 aeroplanes (serials 1–230). \n\nIt affects owners/operators of those older models because corrodible aluminium parts can cause fuel leaks or fire; compliance via Aero Commander Service Bulletins 77/79 or FAA AD 62-8-2 is required before flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif","history":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif/history","analysis":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif/analysis","conflicts":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif/conflicts","importantCases":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif/important-cases","documents":"/api/acts/ad-ac-30-replacement-of-fuel-system-aluminium-drain-tubing-and-fittings-and-wing-trailing-edge-modif/documents"}}