{"id":"F2006B05484","name":"AD/PA-23/57 - Wing Leading Edge - Modification","slug":"ad-pa-23-57-wing-leading-edge-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46299,"registerId":"commonwealth-F2006B05484-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-23/57 - Wing Leading Edge - 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-23/57 Wing Leading Edge - Modification 6/73\n\nApplicability: All model PA-23-250 with S/Nos. 27-4766 to 27-4820. Document:  Piper SB No. 385.\n\nCompliance: Within 100 hours time in service after 29 June 1973.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1599},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, original maintenance directive from June 1973 targeting a specific identified safety issue in a limited production batch of aircraft. It has not expanded beyond its original technical purpose."},"complexity_factors":["Extremely narrow applicability (single model with specific serial number range only)","Single compliance action referencing external technical document (Service Bulletin)","Simple time-based compliance trigger (100 hours time in service)"],"plain_english_summary":"**What this is:** A mandatory safety order (called an **Airworthiness Directive**) issued under the Civil Aviation Regulations. It is a legal instruction requiring specific aircraft owners to carry out a safety modification.\n\n**Who it affects:** Owners and operators of **Piper PA-23-250** model aircraft (Apache and Aztec series) with serial numbers **27-4766 through 27-4820**.\n\n**What you must do:**\n- Modify the **wing leading edge** of the aircraft according to the technical instructions in **Piper Service Bulletin No. 385**\n- Complete this work within **100 hours of flying time** (measured from when the aircraft is in service) after 29 June 1973\n\n**Why it matters:** This directive addresses a specific safety defect identified in this particular batch of aircraft. Operating these planes without making the required modification violates civil aviation law and could create a flight safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-57-wing-leading-edge-modification","history":"/api/acts/ad-pa-23-57-wing-leading-edge-modification/history","analysis":"/api/acts/ad-pa-23-57-wing-leading-edge-modification/analysis","conflicts":"/api/acts/ad-pa-23-57-wing-leading-edge-modification/conflicts","importantCases":"/api/acts/ad-pa-23-57-wing-leading-edge-modification/important-cases","documents":"/api/acts/ad-pa-23-57-wing-leading-edge-modification/documents"}}