{"id":"F2006B04831","name":"AD/CA25/11 - Engine Air Intake Hoses","slug":"ad-ca25-11-engine-air-intake-hoses","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44632,"registerId":"commonwealth-F2006B04831-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 (Hedaro) CA 25 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CA25/11 Engine Air Intake Hoses 7/200","sectionType":"part","heading":"AD/CA25/11 Engine Air Intake Hoses 7/2001","content":"# AD/CA25/11 Engine Air Intake Hoses 7/2001\n\nApplicability: CA25 and CA25N 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_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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific airworthiness issue (engine air intake hose integrity) for a limited fleet of aircraft. The scope remains precisely focused on its original safety purpose with no evidence of scope creep."},"complexity_factors":["Single-issue directive with straightforward applicability (two specific aircraft models)","Clear two-step requirement structure (inspect, then replace if conditions met)","Only 3 specific replacement triggers listed in plain language","Simple compliance timeline with alternative metrics (hours OR months)","One cross-reference to Civil Aviation Orders (CAO Part 95.55) for exemption","Minimal defined terms (relies on standard aviation terminology)"],"plain_english_summary":"This safety order requires owners/operators of Skyfox Aviation CA25 and CA25N light aircraft to inspect—and if necessary replace—engine air intake hoses because certain hoses can collapse under suction and cause in-flight engine failure. Inspect both hoses within 50 flight hours or 3 months and every 50 hours thereafter until replaced; replace immediately if damaged, unidentifiable, or not rated for negative pressure. HRD Thermoid “SCAT”/“SCEET” hoses are not approved. Replacement deadline: before next flight or by 31 Oct 2001."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This directive stays within the original, narrowly focused safety purpose: to identify and remove engine air intake hoses that are unairworthy or not approved for the aircraft's pressure regime. It does not add unrelated obligations, broaden applicability beyond CA25/CA25N aircraft (except for an explicit exclusion for CAO Part 95.55 operators), or convert the safety requirement into a wider regulatory regime. The measures are proportional to that purpose (inspection and replacement) and do not materially expand the legislation's scope beyond correcting the identified unsafe condition."},"complexity_factors":["Clear, single‑subject directive (engine air intake hoses) but with several conditional paths","Applicability carve‑out: excludes aircraft operated under CAO Part 95, section 95.55","Two staged requirements: inspection obligations (Requirement 1) and replacement conditions (Requirement 2)","Repeated inspection interval until replacement: 50 hours or 3 months initial, then every 50 hours until compliance","Multiple distinct compliance deadlines: \"within 50 hours or 3 months\" and hard deadlines (prior to further flight; prior to 31 Oct 2001)","Cross‑references to other regulatory authorisations: CAR 35/36 authorised person for approvals and CAR 1998 subregulation 39.1(1) as enabling power","A manufacturer‑approval condition (approval for negative pressure) plus an explicit note invalidating specific hose types (SCAT, SCEET) for that use","Operational checks both internal and external and traceability requirement (manufacturer ID/spec) can be administratively nontrivial"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Applies to Skyfox Aviation (Hedaro) CA25 and CA25N aeroplanes except those flown under Civil Aviation Orders (CAO) Part 95, section 95.55 (see \"Applicability\").\n- Requires removal and inspection of both engine air intake hoses for internal and external condition (fabric, helix wire, attachment cuff) and for the hose manufacturer’s identification and specification (Requirement 1(a)–(b)).\n- Requires replacement of any hose that is found to be unairworthy, lacks identifiable manufacturer/specification, or is not approved by its manufacturer for negative pressure applications (Requirement 2(a)–(c)).\n- States that certain aeroduct hoses (brands \"SCAT\" and \"SCEET\") are not approved by HRD Thermoid Industries for negative pressure use (Note).\n\n**When the work must be done**\n\n- The first inspection must be done within 50 flight hours or within 3 months from the Directive's effective date, whichever comes first (Compliance: Requirement 1).\n- The inspection must be repeated thereafter at intervals not exceeding 50 flight hours until the replacement requirement is met (Compliance: ongoing intervals).\n- Any hose that requires replacement under Requirement 2 must be replaced prior to further flight in the case of unairworthiness, and in the other two stated cases (unknown manufacturer/spec or not approved for negative pressure) replacement must occur by 31 October 2001 or earlier as specified (Compliance: Requirement 2).\n\n**Who this affects**\n\n- Aircraft operators and owners of CA25 and CA25N aeroplanes not operated under CAO Part 95.55.\n- Certifying personnel: replacement must be carried out or approved by a CAR 35/36 authorised person (Requirement 2).\n- Suppliers/manufacturers of approved hoses, because operators will need hoses that are explicitly approved for negative pressure applications.\n\n**Why it matters (stated purpose and practical effect)**\n\n- The directive is issued to correct an identified unsafe condition related to engine air intake hoses. It does so by forcing inspections and removing hoses that are unserviceable or not approved for the operational pressure regime.\n\n**Who pays, who decides and what changes in behaviour**\n\n- Operators pay: inspection labour, potential downtime, and the cost of replacement hoses and certified fitting.\n- A CAR 35/36 authorised person decides whether a replacement hose is \"approved for the purpose\" (Requirement 2). The CASA delegate issues the directive under CAR 1998 subregulation 39.1(1).\n- Behaviour changes: operators must inspect frequently (every 50 hours until compliant replacement), keep or establish traceability to hose manufacturer/specification, and replace non‑compliant hoses with manufacturer‑approved items before flight or by the specified deadline.\n\n**Implementation, compliance burden and risks**\n\n- Compliance burden is operational (removal and inspection of both hoses), administrative (tracking manufacturer identification/specification), and financial (replacement and certified installation if required).\n- Timing constraints create concentrated short‑term costs: an initial inspection within 50 hours/3 months and replacement deadlines (some by 31 October 2001) mean operators must act quickly.\n- Dependence on CAR 35/36 authorised persons for approval creates a chokepoint: availability of authorised personnel and approved hoses affects how quickly owners can comply.\n- Supply risk: if hoses approved for negative pressure are scarce, operators may face delays or higher prices. The Note explicitly rules out use of specified Aeroduct types for negative pressure, which narrows acceptable supply (Note).\n\n**Trade‑offs and likely market effects**\n\n- Concentrated benefit to manufacturers and suppliers of hoses explicitly approved for negative pressure (they will gain demand). Costs are diffuse across affected operators.\n- Substitution effect: operators will replace ineligible hoses with approved types; some hose types (SCAT, SCEET, per Note) are excluded, shifting demand away from those product lines.\n\n**Fit with stated purpose**\n\n- The requirement is procedural and targeted: inspect, identify, and replace hoses that pose an unsafe condition or cannot be verified as appropriate for negative pressure operations (Requirement 1–2). The mechanical mechanisms for achieving the safety goal are explicit: inspection intervals, identification checks, and mandated replacement with approved parts.\n\n**Key provisions cited**: Applicability; Requirement 1(a)–(b); Requirement 2(a)–(c); Note; Compliance (timing provisions)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ca25-11-engine-air-intake-hoses","history":"/api/acts/ad-ca25-11-engine-air-intake-hoses/history","analysis":"/api/acts/ad-ca25-11-engine-air-intake-hoses/analysis","conflicts":"/api/acts/ad-ca25-11-engine-air-intake-hoses/conflicts","importantCases":"/api/acts/ad-ca25-11-engine-air-intake-hoses/important-cases","documents":"/api/acts/ad-ca25-11-engine-air-intake-hoses/documents"}}