{"id":"F2006B02084","name":"AD/AC/25 - Circuit Breaker Panel - Insulator Inspection","slug":"ad-ac-25-circuit-breaker-panel-insulator-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41314,"registerId":"commonwealth-F2006B02084-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC/25 - Circuit Breaker Panel - Insulator Inspection","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 6/1962,Aircraft below 5700 kg,Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes,Circuit Breaker Panel - Insulator Inspection,25\ntitle: Airworthiness Directive - AD/AC/25 - Circuit Breaker Panel - Insulator Inspection\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)  Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes\n\n \n\nAD/AC/25 Circuit Breaker Panel - Insulator Inspection 6/62\n\nApplicability: Models 520, 560, 560A, 560E, 500 and 680 with S/Nos. 1 to 892. Document:  Aero Commander SL No. 123.\n\nCompliance: At intervals not exceeding 100 hours’ time in service.\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":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text of the AD sets a clear, limited scope (models and serial numbers listed) and a single recurring inspection interval. The instrument does not indicate any expansion or narrowing of that scope compared with its own stated applicability; there is no text here showing a change from an earlier or different scope."},"complexity_factors":["Narrow applicability: specific models and serial number range (Applicability)","Single, simple compliance requirement: inspection at intervals not exceeding 100 hours (Compliance)","Dependence on an external document for procedural details: Aero Commander SL No. 123 (Document)","Lack of procedural detail or enforcement mechanisms in the AD text increases implementation reliance on the referenced service letter","Recurring compliance obligation creating operational scheduling and maintenance-resource considerations"],"plain_english_summary":"# What this instrument does\n\nThis is an Airworthiness Directive (AD) titled \"AD/AC/25 Circuit Breaker Panel - Insulator Inspection\". It requires specified Twin Commander aeroplanes to have the circuit breaker-panel insulators inspected regularly. Mechanically, the directive applies to Models 520, 560, 560A, 560E, 500 and 680 with serial numbers 1 to 892 (Applicability) and requires those inspections to be carried out at intervals not exceeding 100 hours' time in service (Compliance). The AD refers operators to Aero Commander Service Letter No. 123 for the relevant inspection details (Document).\n\n# Who it affects\n\n- Owners and operators of the listed Twin Commander aeroplane models with serial numbers 1–892 (Applicability).  \n- Maintenance personnel who carry out inspections under the referenced Aero Commander Service Letter (Document).\n\n# Who pays and who decides\n\n- Owners/operators pay for and arrange the inspections and any follow-on maintenance or repairs. This follows from the AD's compliance requirement (Compliance) and its applicability to specific aircraft (Applicability).  \n- The Civil Aviation Safety Authority is the issuer of the AD (COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY). Operators must decide how to schedule and document the inspections to meet the AD's interval requirement (Compliance).\n\n# How it works mechanically\n\n- The AD identifies which aircraft are covered by make, model and serial number (Applicability).  \n- It imposes a recurring inspection requirement: inspect the circuit breaker-panel insulators at intervals not exceeding 100 hours' time in service (Compliance).  \n- It points to Aero Commander SL No. 123 for the inspection procedure and presumably for the inspection standard and steps (Document).\n\n# Official rationale (as stated or implied by the instrument)\n\n- The AD's title and form indicate its purpose is to require inspection of circuit breaker-panel insulators. The text itself contains no further narrative justification; readers should treat the AD's title as the stated action to be taken (AD/AC/25 Circuit Breaker Panel - Insulator Inspection).\n\n# Practical implications, trade-offs and risks\n\n- Compliance burden: Operators must allocate maintenance resources and schedule inspections every 100 flight hours or less (Compliance). That creates recurring labour and possibly parts costs if defects are found.  \n- Procedural dependence: The AD references a service letter (Aero Commander SL No. 123) for the inspection method (Document). Operators need access to and must follow that document to implement the AD.  \n- Administrative tasks: Operators must track aircraft time-in-service to ensure inspections occur on schedule (Compliance). The AD text does not specify recordkeeping or enforcement mechanisms.  \n- Discretion and implementation risk: The AD sets a mandatory interval but does not, in the text provided, elaborate on inspection criteria, corrective actions, or acceptable findings; those details appear delegated to the referenced service letter (Document). That means consistent implementation depends on the clarity and availability of that referenced material.  \n- Effects on private choice and operations: Aircraft owners/operators can continue operating the affected aeroplanes if they meet the inspection interval; they must allocate maintenance time and potentially ground the aircraft for inspection/repair when defects are found.  \n\n# Where benefits and costs fall\n\n- Costs fall directly on the owners/operators of the specific serial-numbered aircraft covered by the AD (Applicability; Compliance).  \n- Benefits (detection and remediation of any defect in the circuit breaker-panel insulators) accrue primarily to those same operators and to passengers/users of the affected aircraft. The AD text itself does not quantify benefits or state an economic analysis.\n\n# Implementation note\n\n- To comply, operators should obtain Aero Commander SL No. 123 and schedule inspections at intervals not exceeding 100 hours' time in service, retain evidence of compliance, and carry out any corrective actions that the service letter or maintenance practice prescribe (Document; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive focused on a specific safety issue (circuit breaker panel insulators) for a narrow class of aircraft. It has not expanded beyond its original purpose. The document appears to be a historical directive (Issue 6/62 from 1962) that remains in force, maintaining its original narrow scope."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 1 defined term implicitly used ('time in service')","No cross-references to other legislation sections","Simple conditional logic: single compliance requirement with fixed interval","No exceptions or nested conditions","Single applicability criterion (specific aircraft models and serial numbers)","Straightforward directive structure: applicability → document reference → compliance requirement"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety instruction issued by the Civil Aviation Safety Authority (CASA) that aircraft owners and operators must follow.\n\n**What it does:** It requires regular inspections of the circuit breaker panel insulators on specific Twin Commander aircraft models (including the Gulfstream/Rockwell/Aerocommander 500, 600 and 700 series). \n\n**Who it affects:** Owners and operators of specific Twin Commander aircraft with serial numbers 1 to 892, specifically models 520, 560, 560A, 560E, 500 and 680.\n\n**What must be done:** The circuit breaker panel insulators must be inspected at least every 100 hours of flight time (\"time in service\" means actual flying hours, not just time since last check).\n\n**Why it matters:** Faulty insulators on circuit breaker panels can cause electrical failures or fire hazards. This rule ensures potential problems are caught early through regular inspection, keeping pilots and passengers safe.\n\n**Key details:**\n- **Compliance deadline:** Every 100 hours of flight time\n- **Technical reference:** Aero Commander Service Letter No. 123 (this document tells mechanics exactly how to do the inspection)\n- **Issue number:** 6/62 (originally issued in 1962, showing this is a long-standing safety requirement)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection","history":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection/history","analysis":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection/analysis","conflicts":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection/conflicts","importantCases":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection/important-cases","documents":"/api/acts/ad-ac-25-circuit-breaker-panel-insulator-inspection/documents"}}