{"id":"F2006B05482","name":"AD/PA-23/55 - Fuel System - Inspection and Modification","slug":"ad-pa-23-55-fuel-system-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46292,"registerId":"commonwealth-F2006B05482-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-23/55 - Fuel System - Inspection and 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-23 (Apache and Aztec) Series Aeroplanes\n\n \n\nAD/PA-23/55 Fuel System - Inspection and Modification 11/72\n\nApplicability: All PA-23 series with S/N 27-1 to 27-2504 and 27-2505 to 27-4765. Document:  Piper SL No. 606A.\n\nCompliance: At next major inspection after 30 November 1972.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose airworthiness directive issued in 1972. It has not expanded beyond its original scope of addressing a specific fuel system safety issue in defined Piper aircraft models. The document represents a complete, self-contained regulatory instrument."},"complexity_factors":["Very short document (under 150 words)","Only 4 defined elements: applicability (serial number range), document reference, compliance deadline, and affected aircraft type","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Single, clear compliance action with unambiguous deadline","No conditional logic, exceptions, or nested provisions","Straightforward applicability test based on serial numbers"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific **Piper PA-23 Apache and Aztec aircraft** to inspect and modify their fuel systems.\n\n**Who it affects:**\n- Owners and operators of Piper PA-23 series aeroplanes with serial numbers 27-1 through 27-4765\n\n**What it requires:**\n- A mandatory inspection and modification of the fuel system\n- Must be carried out at the next major aircraft inspection after 30 November 1972\n- The work must follow Piper Service Letter No. 606A (the manufacturer's official instructions)\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. They are issued when a safety defect is found that could affect flight safety. Non-compliance means the aircraft cannot legally fly in Australian airspace. This particular AD addresses potential fuel system problems in these specific Piper aircraft models."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied AD text defines its scope directly: it applies to PA-23 series aircraft within two specified serial number ranges and requires inspection/modification at the next major inspection after 30 November 1972. The document does not indicate any change from an earlier or different scope in the supplied text."},"complexity_factors":["Narrow and clearly defined applicability by specific serial number ranges (straightforward identification).","Single compliance trigger: the next major inspection after a specific date (simple timing rule).","Technical requirements are external to the AD (Piper Service Letter No. 606A) — AD is procedural, so implementers must consult another document for details.","No procedural ambiguity in the AD text itself, but reliance on an external service letter creates a lookup/administrative step.","No staged or conditional requirements, no reporting, no exemption or approval pathways included in the supplied text."],"plain_english_summary":"This AD mandates inspection and modification of the fuel system on certain Piper PA‑23 (Apache/Aztec) aeroplanes, directing maintenance to follow Piper Service Letter No. 606A. It applies to aircraft with serial numbers 27‑1 through 27‑4765 (in the two specified ranges).\n\nCompliance is required at the next major inspection after 30 November 1972. Owners/operators and their maintenance organisations must schedule and pay for the work and obtain Service Letter No. 606A for the technical instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification","history":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification/history","analysis":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification/analysis","conflicts":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification/important-cases","documents":"/api/acts/ad-pa-23-55-fuel-system-inspection-and-modification/documents"}}