{"id":"F2006B05539","name":"AD/PA-24/40 - Aileron Nose Rib - Inspection and Modification","slug":"ad-pa-24-40-aileron-nose-rib-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46454,"registerId":"commonwealth-F2006B05539-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-24/40 - Aileron Nose Rib - 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-24 (Comanche) Series Aeroplanes\n\n \n\nAD/PA-24/40 Aileron Nose Rib - Inspection and Modification 3/80\n\nApplicability: All models: PA-24-180 and 250 with S/Nos. 24-1 and up, PA-24-260 with S/Nos.\n\n24-4000 and up, and PA-24-400 with S/Nos. 26-1 and up.\n\n \n\nDocument: 1. Piper SL No. 850; or\n\n \n\n2. FAA AD 79-20-10, Amdt. 39-3579.\n\n \n\nCompliance: Inspect within 100 hours time in service after 30 November 1979 and thereafter at intervals not exceeding 100 hours time in service until modified by fitting Piper Kit Part No. 763 893.\n\n \n\nBackground: The manufacturer has received reports of cracks developing in the aileron nose rib of several aeroplanes regardless of any previous modification kit fitted.\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":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness concern. It has not expanded beyond its original purpose of mandating inspection and modification for a known structural defect."},"complexity_factors":["Single, specific mechanical defect addressed (aileron nose rib cracking)","Clear applicability criteria (specific aircraft models and serial numbers)","Simple compliance timeline (100 hours time-in-service, recurring until modification)","Only two reference documents cited (Piper Service Letter and FAA AD)","No defined terms section, no cross-references to other legislation, no conditional exceptions","Total length is approximately 150 words"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Piper PA-24 Comanche aircraft** (certain serial numbers of the 180, 250, 260, and 400 horsepower models).\n\n**What it requires:**\n- **Inspect** the aileron nose rib (a structural part of the wing's control surface) for cracks within 100 hours of flying time after 30 November 1979, and then **re-inspect every 100 hours** thereafter.\n- **Eventually modify** the aircraft by installing a specific Piper repair kit (Part No. 763 893). Once this modification is done, the recurring inspections stop.\n\n**Why it matters:**\nThe manufacturer received reports of cracks forming in this part — a potential safety risk. This AD ensures aircraft owners check for this defect regularly until a permanent fix is installed. Ignoring an AD is illegal and the aircraft cannot fly legally until compliance is achieved.\n\n**Who must comply:**\nOwners and operators of the affected Piper PA-24 aircraft."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text sets out a defined applicability and a clear compliance regime (recurring inspections until the specified Piper kit is fitted). It does not state any expansion or narrowing of scope relative to a prior instrument within this text; the document itself establishes the inspection-and-modification requirement for the listed serial-number ranges. (Applicability; Compliance)"},"complexity_factors":["Narrow technical scope limited to a specific component (aileron nose rib) on specified PA-24 serial-number ranges (Applicability).","Single clear compliance requirement with a fixed interval (inspect within 100 hours after 30 Nov 1979 and every 100 hours thereafter) and a defined terminating action (fit Piper Kit Part No. 763 893) (Compliance).","Dependence on external technical documents for procedural detail (Piper SL No. 850 or FAA AD 79-20-10) increases implementation steps though not legal ambiguity (Document).","No alternative compliance, exceptions, or detailed enforcement/discretionary provisions in the text, which simplifies legal interpretation but shifts procedural detail to referenced documents (Compliance; Document).","Serial-number based applicability requires checking individual aircraft records to determine coverage (Applicability)."],"plain_english_summary":"Owners/operators of specified Piper PA‑24 series aeroplanes must inspect the aileron nose rib every 100 hours (starting within 100 hours after 30 Nov 1979) until Piper Kit Part No. 763 893 is fitted, which removes the recurring inspection. The measure responds to reported rib cracking, shifts costs and work onto owners (recurring inspections versus one‑time kit installation), and refers to Piper Service Letter No. 850 or FAA AD 79‑20‑10 for procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification","history":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification/history","analysis":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification/analysis","conflicts":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification/important-cases","documents":"/api/acts/ad-pa-24-40-aileron-nose-rib-inspection-and-modification/documents"}}