{"id":"F2006B11438","name":"AD/P166/10 - Undercarriage Warning Horn Circuit - Modification","slug":"ad-p166-10-undercarriage-warning-horn-circuit-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57373,"registerId":"commonwealth-F2006B11438-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P166/10 - Undercarriage Warning Horn Circuit - 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/P166/10 Undercarriage Warning Horn Circuit - Modification NK\n\nApplicability: S/Nos. prior to 409.\n\n \n\nRequirement: Connect the undercarriage warning horn switches in parallel. Compliance: 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\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive. Airworthiness Directives are inherently narrow instruments addressing specific technical defects in specific aircraft types. There is no indication of scope creep; the directive addresses exactly one identified safety issue with a precise technical remedy."},"complexity_factors":["Extremely short document (under 100 words of substantive content)","No defined terms section","No cross-references to other legislation","Single, unambiguous requirement with no exceptions or conditions","No procedural steps or alternative compliance methods","Plain language directive ('Connect... in parallel', 'Forthwith')","Narrow applicability (specific aircraft serial numbers only)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Piaggio P166 series aircraft** (those with serial numbers before 409).\n\n**What it does:**\n- Requires a simple electrical modification to the landing gear (undercarriage) warning system\n- The warning horn switches must be rewired so they work **in parallel** rather than in series (meaning if one switch fails, the others still work — redundancy for safety)\n\n**Who it affects:**\n- Owners and operators of older Piaggio P166 aircraft (serial numbers 1-408)\n- Maintenance engineers who must carry out the work\n\n**Why it matters:**\n- Prevents situations where a single switch failure silences the landing gear warning horn\n- The warning horn alerts pilots if they try to land with the wheels up — a potentially catastrophic error\n- Must be done **\"forthwith\"** (immediately, without delay)\n\n**In short:** A quick, cheap wiring fix that could save lives by ensuring pilots always get warned about landing gear problems."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text of this AD specifies a narrowly targeted change (connect switches in parallel) for a defined set of serial numbers and requires immediate compliance. The instrument itself contains no indication that its scope has been altered from any earlier or original intent; it states applicability and the single required modification only (Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow and clear applicability: applies only to Piaggio P166 with S/Nos prior to 409 (Applicability)","Single, simple technical requirement: connect undercarriage warning horn switches in parallel (Requirement)","Immediate compliance required: 'Forthwith' creates time pressure but does not add procedural complexity (Compliance)","Lack of technical implementation detail: AD specifies end-state but provides no step-by-step instructions, parts list, or approval process (Requirement)","Enforcement and procedural discretion not described: CASA issues the AD but the text does not specify how compliance verification is to be carried out (header; Compliance)"],"plain_english_summary":"This AD requires the undercarriage warning-horn switches on Piaggio P166 aeroplanes (S/Ns prior to 409) to be rewired in parallel, with compliance required forthwith.\n\nIt affects owners/operators and maintenance providers by imposing immediate maintenance, downtime and direct costs; the directive specifies the required electrical end-state but gives no detailed procedures, parts list or funding allocation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification","history":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification/history","analysis":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification/analysis","conflicts":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification/conflicts","importantCases":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification/important-cases","documents":"/api/acts/ad-p166-10-undercarriage-warning-horn-circuit-modification/documents"}}