{"id":"F2006B04826","name":"AD/CA21/7 Amdt 1 - Aileron Hanger Ribs","slug":"ad-ca21-7-amdt-1-aileron-hanger-ribs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44627,"registerId":"commonwealth-F2006B04826-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CA21/7 Amdt 1 - Aileron Hanger Ribs","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n![](image.002.png)  \nSkyfox Aviation (Calair/Hedaro) CA21 and CA22A Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/CA21/7 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAD/CA21/7\n\nAmdt 1\n\n  \nAileron Hanger Ribs 9/2000 DM\n\nApplicability: All CA21, CA22 and CA22A aircraft.\n\nRequirement: Inspect and test all aileron hanger rib extensions in accordance with the Accomplishment Instructions of Skyfox Aviation Ltd Service Bulletin No. 24, Initial Issue, dated 27 February 1998.\n\nCompliance: Before further flight after 2 August 2000; thereafter at intervals not to exceed 100 hours or 12 months, whichever occurs first.\n\nThis Amendment becomes effective on 2 August 2000.\n\nBackground: During an unscheduled inspection, an aileron hanger rib extension was broken with little downward pressure. The purpose of this Directive was to check the structural integrity of all aircraft in-operation which may be similarly affected.\n\nAmendment 1 is issued in response to a deteriorated aileron hanger rib found on a Skyfox CA25N aircraft that recently suffered an in-flight separation of the right hand aileron. This Directive requires further inspections of the aileron hanger ribs.\n\nThe original issue of this Airworthiness Directive became effective on 3 March 1998.\n\n![](image.003.png)  \n\nNeville James Probert\n\nDelegate of the Civil Aviation Safety Authority 27 July 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 2 August 2000.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: ensuring the structural integrity of aileron hanger ribs on specific Skyfox aircraft models. The amendment expands the inspection requirements slightly in response to new safety data (the in-flight aileron separation incident), but this is a natural evolution within the original safety scope rather than scope creep. The directive does not extend to other aircraft types, other aircraft systems, or unrelated regulatory matters."},"complexity_factors":["Single, clearly defined applicability (three specific aircraft models)","One primary requirement with a single reference to an external technical document (Service Bulletin No. 24)","Simple compliance structure: initial deadline plus recurring interval (100 hours/12 months)","No defined terms section, no cross-references to other legislation beyond the enabling regulation (CAR 1998)","Background narrative is plain English and explains the safety rationale clearly","Total length is approximately one page"],"plain_english_summary":"This CASA safety order replaces an earlier directive and requires owners/operators of Skyfox CA21, CA22 and CA22A aeroplanes to inspect and test the aileron hanger rib (per Manufacturer Service Bulletin No. 24) before flying after 2 Aug 2000, and thereafter every 100 flight hours or 12 months. It responds to incidents where aileron hanger ribs failed and an aileron detached in flight, posing a severe safety risk."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No. The amendment does not expand which aircraft are covered: applicability remains all CA21, CA22 and CA22A aircraft. The AD does, however, require further inspections in response to a separate CA25N incident, increasing the required inspection action for the existing covered fleet rather than broadening coverage (Applicability; Background; Requirement)."},"complexity_factors":["Clear, narrow technical requirement limited to inspection/testing of a single component (Requirement).","Dependence on an external document (Skyfox Service Bulletin No. 24) for the detailed procedure — compliance requires access to and correct application of that Service Bulletin (Requirement).","Recurring compliance timing (100 flight hours or 12 months) creates operational scheduling and cost burdens for operators (Compliance).","Safety-critical nature of the component means findings may require repairs or grounding, increasing direct costs and operational disruption (Background; Requirement).","Regulatory enforcement and decision-making are exercised by a CASA delegate, creating administrative oversight obligations for operators (introductory paragraph; signature).","Background references an incident on a CA25N without adding that model to applicability, which could create interpretive uncertainty for some operators (Background)."],"plain_english_summary":"This Airworthiness Directive requires all Skyfox CA21, CA22 and CA22A aeroplanes to have their aileron hanger rib extensions inspected and tested following Skyfox Service Bulletin No. 24. Inspections must be done before further flight after 2 August 2000 and then every 100 flight hours or 12 months, whichever occurs first. CASA (delegate) issued the directive; aircraft operators bear the inspection and repair costs. The measure responds to found failures of hanger ribs and aims to detect and correct structural defects."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs","history":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs/history","analysis":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs/analysis","conflicts":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs/conflicts","importantCases":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs/important-cases","documents":"/api/acts/ad-ca21-7-amdt-1-aileron-hanger-ribs/documents"}}