{"id":"F2006B04819","name":"AD/CA21/11 - Engine Air Intake Hoses","slug":"ad-ca21-11-engine-air-intake-hoses","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44617,"registerId":"commonwealth-F2006B04819-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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\n![](image.001.png)\n\nSkyfox Aviation (Calair/Hedaro) CA 21 and CA22A Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CA21/11 Engine Air Intake Hoses 7/200","sectionType":"part","heading":"AD/CA21/11 Engine Air Intake Hoses 7/2001","content":"# AD/CA21/11 Engine Air Intake Hoses 7/2001\n\nApplicability: CA21, CA22 and CA22A, aircraft other than aircraft operated in accordance with Civil Aviation Orders Part 95, Section 95.55.\n\nRequirement: 1. (a) Remove both engine air intake hoses and inspect hoses internally and externally for fabric, helix wire and attachment cuff condition, and\n\n(b) inspect both engine air intake hoses for evidence of the hose manufacturer’s identification and hose specification.\n\n    2. Replace engine intake hoses with hoses approved for the purpose by a CAR 35/36 authorised person when it is established the installed hose:\n\n    (a) Is not airworthy, or\n\n    (b) The hose manufacturer or hose specification cannot be identified, or\n\n    (c) The hose is not approved by the hose manufacturer for negative pressure applications.\n\nNote: Aeroduct “SCAT” and “SCEET” hoses are not approved by the hose manufacturer HRD Thermoid Industries for use in negative pressure applications.\n\nCompliance: Requirement 1: Within 50 hours or 3 months, whichever occurs first, time in service\n\nfrom the effective date of this Directive and thereafter at intervals not to exceed 50 hours time in service until Requirement 2 of this Directive is carried out.\n\nRequirement 2: (a) Prior to further flight.\n\n    (b) Prior to 31 October 2001.\n\n    (c) Prior to 31 October 2001.\n\nThis Airworthiness Directive becomes effective on 12 July 2001.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive applies narrowly to Skyfox CA21, CA22 and CA22A aircraft (excluding Part 95 operations) and prescribes inspection and replacement requirements for engine air‑intake hoses. Nothing in the text indicates an expansion or narrowing of that applicability beyond the stated corrective measures."},"complexity_factors":["Technical criterion: requirement that hoses be approved for negative pressure applications (requires technical verification of hose specification).","Identification burden: inspections must confirm manufacturer identification and hose specification before allowing continued use.","Repeated compliance: 50‑hour/3‑month initial window and mandatory 50‑hour repeat inspections until replacement increases ongoing monitoring.","Multiple replacement triggers: three distinct replacement conditions (unairworthy, unidentified, not manufacturer‑approved) create decision points for operators.","Regulatory actors: replacement must be carried out or approved by a CAR 35/36 authorised person, adding certification dependency.","Applicability carve‑out: exclusion of aircraft operated under CAO Part 95 affects scope and who bears costs.","Manufacturer note: explicit exclusion of certain Aeroduct hoses (SCAT/SCEET) requires operators to identify acceptable substitutes.","Fixed deadlines: some replacement requirements have hard dates (prior to 31 Oct 2001) and a near‑term effective date, raising implementation urgency."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Skyfox CA21, CA22 and CA22A (except aircraft flown under Civil Aviation Orders Part 95) to inspect engine air‑intake hoses within 50 flight hours or 3 months and then every 50 hours until replaced, and to replace any hose that is unairworthy, lacks manufacturer identification/specification, or is not approved for negative‑pressure use. CASA issued the AD to correct an identified unsafe condition; affected operators pay for inspections and CAR 35/36‑authorised replacements and must avoid hoses not approved by the manufacturer."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It targets a specific unsafe condition (potential failure of engine air intake hoses) on specific aircraft models (Skyfox CA21/CA22 series). There is no evidence of scope creep; the directive remains tightly focused on the identified safety issue with clear applicability limits."},"complexity_factors":["Single, specific technical subject matter (engine hoses on three aircraft models)","Only 2 main requirements with clear sub-paragraphs (a), (b), (c)","Minimal cross-referencing (only to CAR 1998 subregulation 39.1(1) and CAR 35/36 for authorised persons)","Straightforward compliance timeline with simple alternatives (50 hours OR 3 months)","One explicit exception (aircraft under CAO Part 95 Section 95.55)","No nested definitions or interpretation sections","Total length: approximately 300 words"],"plain_english_summary":"This CASA safety order requires owners/operators of Skyfox CA21/CA22/CA22A aircraft (except those operating under CAO Part 95.55 recreational rules) to inspect—and where necessary replace—the engine air intake hoses because certain hoses can collapse under suction and cause engine power loss or failure.\n\nInspections are mandated within 50 flight hours or 3 months (and repeated until replacement); hoses that are damaged, unidentifiable, not rated for negative pressure, or of banned SCAT/SCEET types must be replaced (deadline for unspecified/wrong types: 31 Oct 2001)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ca21-11-engine-air-intake-hoses","history":"/api/acts/ad-ca21-11-engine-air-intake-hoses/history","analysis":"/api/acts/ad-ca21-11-engine-air-intake-hoses/analysis","conflicts":"/api/acts/ad-ca21-11-engine-air-intake-hoses/conflicts","importantCases":"/api/acts/ad-ca21-11-engine-air-intake-hoses/important-cases","documents":"/api/acts/ad-ca21-11-engine-air-intake-hoses/documents"}}