{"id":"F2006B05333","name":"AD/P166/7 - Electrical Supply - Turn and Bank Indicator, Fire Warning System and Stall Warning Indicator - Modification","slug":"ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45809,"registerId":"commonwealth-F2006B05333-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P166/7 - Electrical Supply - Turn and Bank Indicator, Fire Warning System and Stall Warning Indicator - Modification","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)  Piaggio P166 Series Aeroplanes\n\n \n\nAD/P166/7 Electrical Supply - Turn and Bank Indicator, NK Fire Warning System and Stall Warning\n\nIndicator - Modification\n\n \n\nApplicability: S/Nos. prior to 409.\n\n \n\nRequirement: Provide independent circuit protection for the turn and bank indicator, the fire warning system and the stall warning indicator.\n\n \n\nCompliance: Forthwith.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The supplied text contains a standalone airworthiness directive that applies to Piaggio P166 aeroplanes with serial numbers prior to 409 and requires independent circuit protection for three specified systems, with compliance required \"Forthwith.\" The instrument itself does not indicate any change from an earlier scope or intent within the supplied text, so there is no evidence here that the scope has changed from an original intent."},"complexity_factors":["Narrow and specific scope (single aircraft type, serial numbers prior to 409) reduces breadth of complexity.","Technical ambiguity: the directive requires \"independent circuit protection\" but supplies no technical specification or standard in the text.","Immediate compliance timeframe (\"Forthwith\") raises operational and scheduling complexity for operators.","Regulatory certification required for the implemented solution introduces procedural and approval steps.","Practical implementation requires parts procurement and certified maintenance labour, creating logistical complexity.","Enforcement under Civil Aviation Regulations creates legal/regulatory compliance overhead for owners/operators."],"plain_english_summary":"What this instrument does (mechanically)\n\n- It requires Piaggio P166 series aeroplanes with serial numbers prior to 409 to have \"independent circuit protection\" installed for three electrical systems: the turn and bank indicator, the NK fire warning system, and the stall warning indicator. (See: \"Applicability\"; \"Requirement\")\n- The time for compliance is immediate: the directive says \"Forthwith.\" (See: \"Compliance\")\n- The directive is issued under the Civil Aviation regulatory framework and appears in the Civil Aviation Safety Authority schedule of airworthiness directives. (See header: \"Commonwealth of Australia (Civil Aviation Regulations 1998), PART 39 - CIVIL AVIATION SAFETY AUTHORITY; SCHEDULE OF AIRWORTHINESS DIRECTIVES\")\n\nWho is affected and who decides\n\n- Owners and operators of Piaggio P166 aeroplanes with serial numbers prior to 409 must arrange and pay for the modification required by the directive. (See: \"Applicability\"; \"Requirement\")\n- Maintenance organisations, certifying engineers and approved maintenance staff will carry out the work and record compliance as required by aviation maintenance regulations.\n- The Civil Aviation Safety Authority operates as the issuing authority for the directive and enforces compliance. (See header)\n\nWhy this matters (stated and inferred)\n\n- The directive itself states the required change but does not set out a textual rationale in the supplied text. A reasonable inference from the technical requirement is that providing independent circuit protection reduces the risk that a single electrical fault will disable multiple systems simultaneously. That inference explains why regulators typically mandate independent protection for separate flight- and safety‑critical systems. (Inference based on the \"Requirement\")\n\nPractical effects, incentives and trade-offs\n\n- Who pays: Aircraft owners/operators bear direct costs (parts, labour, possible downtime and inspection/certification fees) because they must perform the modification to each affected aircraft. (See: \"Applicability\"; \"Requirement\")\n- Compliance burden: The modification requires engineering work and maintenance resources. The directive gives no technical detail in the supplied text about exactly what constitutes acceptable \"independent circuit protection,\" so detailed engineering specification and approval will be needed from maintenance-certifying authorities before work proceeds. This uncertainty increases the administrative and design burden on maintainers. (See: \"Requirement\")\n- Timing and operational impact: Because compliance is required \"Forthwith,\" operators may need to take aircraft out of service at short notice, creating immediate operational disruption and opportunity costs (lost flights, re‑scheduling, or temporary replacement capacity). (See: \"Compliance\")\n- Regulatory discretion and implementation risk: The issuing authority prescribes the requirement but the supplied text does not specify precise technical standards, so safety approvals and acceptance of the specific circuit-protection solution will depend on competent persons/organisations and the regulator's certification processes. That creates implementation risk (delay or multiple rework cycles) if proposed modifications do not meet certifying expectations. (See: header; \"Requirement\")\n- Effects on private businesses and markets: The modification creates demand for parts and maintenance labour. Approved maintenance organisations and certifying engineers can perform the work, subject to applicable approvals; that may increase short-term revenue for qualified firms and raise operating costs for affected owners. The directive does not, in the supplied text, create ongoing recurring charges beyond normal maintenance. (See: \"Requirement\")\n- Concentration of costs and benefits: Costs (parts, labour, downtime) fall directly and immediately on the owners/operators of the specified serial-number aircraft. The safety benefit from segregating electrical circuits is borne by operators, passengers and the public but is diffuse relative to the concentrated compliance cost. (See: \"Applicability\"; \"Requirement\")\n\nUncertainties and compliance considerations\n\n- The short text supplied does not define the technical standard for \"independent circuit protection,\" so businesses must seek technical guidance and approval from the appropriate certifying authorities before implementing a solution. (See: \"Requirement\")\n- The AD applies only to aircraft with serial numbers prior to 409, so newer aircraft (409 and later) are outside its scope. That limits the population affected but concentrates work on older airframes. (See: \"Applicability\")\n- Enforcement is via the Civil Aviation Safety Authority's airworthiness directive process; the directive’s immediate compliance requirement means operators should plan for prompt action to avoid regulatory non‑compliance. (See: header; \"Compliance\")"},"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific safety issue in a specific aircraft type. It has not expanded beyond its original technical safety purpose."},"complexity_factors":["Extremely short document (approximately 150 words total)","Only 1 defined term implicitly used (S/Nos. = serial numbers)","No cross-references to other legislation or regulations","Simple unconditional requirement with no exceptions or conditional logic","Single compliance deadline with no alternative methods or phased implementation","Narrow applicability (specific aircraft model and serial number range only)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for **Piaggio P166 series aircraft**.\n\n**What it does:**\n- Requires owners/operators of specific P166 aeroplanes (those with serial numbers before 409) to modify the electrical system\n- Specifically, they must install **independent circuit protection** (separate fuses or circuit breakers) for three critical safety systems:\n  - The **turn and bank indicator** (shows if the plane is turning or banking)\n  - The **fire warning system** (alerts pilots to engine fires)\n  - The **stall warning indicator** (warns when the plane is at risk of stalling)\n\n**Why it matters:**\nPreviously, these three vital safety systems likely shared electrical circuits with other equipment. If one system failed or short-circuited, it could knock out all three simultaneously. This directive prevents that dangerous scenario by ensuring each system has its own dedicated electrical protection.\n\n**Who must comply:**\nAnyone operating a Piaggio P166 with a serial number below 409 must make this modification **immediately** (\"forthwith\" means right away, not at the next scheduled maintenance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-","history":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-/history","analysis":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-/analysis","conflicts":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-/conflicts","importantCases":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-/important-cases","documents":"/api/acts/ad-p166-7-electrical-supply-turn-and-bank-indicator-fire-warning-system-and-stall-warning-indicator-/documents"}}