{"id":"F2006B08541","name":"AD/CHA/15 - Wing Front Strut Aerobatic Fatigue Life Limitation","slug":"ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51320,"registerId":"commonwealth-F2006B08541-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CHA/15 - Wing Front Strut Aerobatic Fatigue Life Limitation","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)  American Champion (Aeronca, Bellanca) Series Aeroplanes\n\n \n\nAD/CHA/15 Wing Front Strut Aerobatic Fatigue Life Limitation 4/76\n\nApplicability: All model 8KCAB aircraft.\n\n \n\nRequirement: Retire the wing front strut assembly, including the aluminium end fittings, from service.\n\n \n\nCompliance: Before achieving 1100 aerobatic flying hours.\n\n \n\nNote: The hours are those actually spent in aerobatic flight and do not include positioning time.\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\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a vintage directive (originally issued 4/76, hence 'AD/CHA/15') that has remained tightly focused on its original purpose: preventing fatigue failure in a specific aerobatic aircraft component. The scope has not expanded beyond the original 8KCAB model target."},"complexity_factors":["Single, unambiguous requirement with no conditional logic","Only one defined term implicitly clarified ('positioning time' explained in Note)","No cross-references to other legislation or regulations","No exceptions, exemptions, or nested provisions","Extremely short document (under 150 words of substantive content)","Clear applicability statement limiting scope to one specific aircraft model"],"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). Think of it like a compulsory recall notice, but for aircraft parts.\n\n**What it does:** It forces owners and operators of specific American Champion aeroplanes (model 8KCAB — a type of light aerobatic aircraft) to permanently remove and replace a critical part: the **wing front strut assembly** (the metal support that holds the wing to the fuselage, including its aluminium end fittings).\n\n**Why it matters:** The wing strut can develop metal fatigue (tiny cracks from repeated stress) after intensive aerobatic use. If the strut fails in flight, the wing could detach — with catastrophic results. This rule prevents that by setting a hard \"use-by date\" on the part.\n\n**The deadline:** You must replace the strut **before** the aircraft clocks up **1,100 hours of actual aerobatic flying time**. \"Positioning time\" (flying to and from the aerobatics area) doesn't count — only time spent doing aerobatics.\n\n**Who must comply:** Anyone operating a model 8KCAB aircraft in Australia, whether privately owned, in flight schools, or in aerobatic competition."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument sets a discrete retirement requirement for a specified component on a specified aircraft model and provides the compliance metric (1,100 aerobatic hours). On the face of the text provided there is no indication that the scope was broadened or narrowed from an earlier intent; the directive plainly states applicability (all model 8KCAB), requirement (retire assembly including aluminium end fittings), and compliance threshold (before 1,100 aerobatic flying hours) with no additional scope-altering conditions."},"complexity_factors":["Narrow technical scope: single aircraft model (8KCAB) and single component (wing front strut assembly including aluminium end fittings) reduces legal complexity.","Clear numeric compliance threshold (1,100 aerobatic hours) simplifies measurement but requires accurate hour-tracking systems.","Operational ambiguity risk: the instrument requires counting only 'hours actually spent in aerobatic flight' which places a recordkeeping and definitional burden on operators.","No alternative compliance or exemption language in the text increases operational rigidity (no discretion provided in the instrument itself).","Practical implementation dependencies (availability of replacement parts, maintenance downtime) are external to the directive but materially affect compliance feasibility.","Concentrated stakeholder impact: small population of affected operators facing potentially significant per-unit replacement cost increases enforcement and dispute potential."],"plain_english_summary":"This instrument mandates removal from service of the wing front strut assembly (including aluminium end fittings) on American Champion 8KCAB aircraft before any individual assembly accumulates 1,100 aerobatic flying hours. Owners and operators of all 8KCAB aeroplanes must comply; aerobatic hours only are counted (positioning excluded).\n\nIt creates direct replacement costs, downtime and a recordkeeping obligation to track aerobatic hours precisely, with no exemptions or alternative compliance paths set out."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation","history":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation/history","analysis":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation/analysis","conflicts":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation/conflicts","importantCases":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation/important-cases","documents":"/api/acts/ad-cha-15-wing-front-strut-aerobatic-fatigue-life-limitation/documents"}}