{"id":"F2006B05673","name":"AD/PA-30/31 - Aileron Nose Rib - Inspection and Modification","slug":"ad-pa-30-31-aileron-nose-rib-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135412,"registerId":"commonwealth-F2006B05673-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-30/31 - 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-30 & 39 (Twin Comanche) Series Aeroplanes\n\n \n\nAD/PA-30/31 Aileron Nose Rib - Inspection and Modification 11/79\n\nApplicability: All models: PA-30 with S/Nos. 30-1 and up, and PA-39 with S/Nos. 39-1 and up. Document:               1. Piper SL NO. 850; or\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 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\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 mechanical defect in specific aircraft models. It has not expanded beyond its original purpose of ensuring aileron nose rib integrity."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined applicability criteria (serial number ranges)","Simple binary compliance path: inspect repeatedly OR modify once","No nested exceptions or conditional logic","Single technical reference to external documents (Piper Service Letter or FAA AD)","Clear, unambiguous deadline structure (100 hours time-in-service)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Piper twin-engine aircraft (the PA-30 \"Twin Comanche\" and PA-39 models) to **inspect the aileron nose rib** — a structural part near the front of the wing's control surface — for cracks.\n\n**Who it affects:** Anyone who owns or operates:\n- **Piper PA-30** aircraft with serial numbers 30-1 and above\n- **Piper PA-39** aircraft with serial numbers 39-1 and above\n\n**What must be done:**\n- **First inspection:** Within 100 hours of flying time after 30 November 1979\n- **Ongoing inspections:** Every 100 hours of flying time thereafter\n- **Permanent fix:** Install **Piper Kit No. 763 893** to modify the aileron nose rib. Once this kit is installed, the repetitive inspections can stop.\n\n**Why it matters:** The manufacturer discovered cracks forming in this part on multiple aircraft — even those that had previous modifications. Cracks in control surfaces can lead to **loss of aircraft control**, so this directive prevents potential accidents by catching problems early or permanently fixing them.\n\n**Key documents to follow:** Either Piper Service Letter No. 850 or the equivalent US Federal Aviation Administration directive (FAA AD 79-20-10)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's text sets out the original scope: applicable aircraft by model and serial number, a 100-hour inspection interval until fitting Piper Kit No. 763 893, and references to Piper/FAA documents. Nothing in the supplied text indicates a change in scope from that stated intent; it consistently prescribes inspections followed by a specific modification as the resolution. (Applicability; Compliance; Document)"},"complexity_factors":["Clear, narrow applicability by model and serial number (PA-30 S/N 30-1+; PA-39 S/N 39-1+). (Applicability)","Simple, fixed compliance interval (inspect within 100 hours after 30 Nov 1979 and every 100 hours thereafter until modification). (Compliance)","Requirement points to external technical documents (Piper Service Letter No. 850; FAA AD 79-20-10) for procedure and detail, requiring cross-referencing. (Document)","Mandates a specific modification kit (Piper Kit No. 763 893) but does not specify installation procedure or parts availability in the text. (Compliance)","Lacks procedural detail on inspection methods, recordkeeping, and enforcement within this text — those details are left to referenced documents or regulator/operator practice. (Compliance; Document)"],"plain_english_summary":"This directive requires owners/operators of Piper PA‑30 (S/N 30‑1+) and PA‑39 (S/N 39‑1+) to perform recurring inspections of the aileron nose rib and to fit Piper Kit No. 763 893 as the permanent fix — inspections are on a 100‑hour cycle until the kit is installed.  \n\nIt responds to reported cracking, affects aircraft owners, operators and maintainers, and places inspection, downtime and kit/installation costs on those parties (see Piper Service Letter No. 850 / FAA AD 79‑20‑10)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification","history":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification/history","analysis":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification/analysis","conflicts":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification/important-cases","documents":"/api/acts/ad-pa-30-31-aileron-nose-rib-inspection-and-modification/documents"}}