{"id":"F2006B05335","name":"AD/P166/9 - Generator Circuit - Modification","slug":"ad-p166-9-generator-circuit-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45817,"registerId":"commonwealth-F2006B05335-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P166/9 - Generator 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/P166/9 Generator Circuit - Modification NK\n\nApplicability: S/Nos. prior to 409.\n\n \n\nRequirement: Remove remote reset circuit breakers fitted between the generator and the reverse circuit relay. Circuit protectors (either limiters or remote reset circuit breakers) shall be installed between the bus and the reverse current relay. Limiters, if used, need not be accessible in flight.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive. It has not expanded beyond its original purpose of addressing a specific electrical system safety issue in a defined aircraft model range."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined applicability criteria (aircraft model series and serial number range)","Single technical requirement with two components (removal and installation)","No cross-references to other legislation or regulations","No conditional logic or exceptions beyond the serial number applicability","Simple compliance deadline (immediate, no phased implementation)"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:** This directive applies to Piaggio P166 series aeroplanes with serial numbers prior to 409. It requires owners/operators to:\n- **Remove** remote reset circuit breakers currently installed between the generator and the reverse current relay\n- **Install** circuit protectors (either limiters or remote reset circuit breakers) between the bus and the reverse current relay instead\n- If using limiters, they don't need to be accessible during flight\n\n**Who it affects:** Owners and operators of specific Piaggio P166 aircraft (older models, serial numbers before 409).\n\n**Why it matters:** This is a safety-critical electrical system modification. The generator circuit and reverse current relay protect the aircraft's electrical system from damage. Moving the circuit protection to between the bus and relay (rather than generator and relay) likely addresses a fire risk or system failure mode that could compromise flight safety.\n\n**When to comply:** Immediately (\"Forthwith\")."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive imposes a specific modification on affected aircraft (S/Ns prior to 409) but the source text does not indicate that the scope of the aircraft type certification or the original design approval is being altered. The AD applies additional equipment/remove-and-replace requirements to a defined subset of the fleet; no text in the instrument signals a change from the original stated applicability or intent."},"complexity_factors":["Narrow applicability: affects only Piaggio P166 aircraft with serial numbers prior to 409 (Applicability).","Simple mechanical instruction: remove a specific component and install a specified type of protector (Requirement).","Clear timing: immediate compliance required (Compliance: Forthwith).","Limited technical options: provides two alternative protector types and specifies an accessibility condition for limiters (Requirement).","No procedural or administrative complexity contained in the text: the AD does not include detailed installation procedures, alternative compliance pathways, or staged deadlines, which reduces textual complexity but shifts technical detail to maintenance documentation or regulator interaction."],"plain_english_summary":"This AD requires owners/operators of Piaggio P.166 aeroplanes S/Ns prior to 409 to remove any remote-reset circuit breakers fitted between the generator and the reverse-current relay and to install a circuit protector (either a current limiter or a remote-reset breaker) between the bus and the reverse-current relay. \n\nCompliance is required forthwith; affected owners/operators bear the cost and must carry out the modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p166-9-generator-circuit-modification","history":"/api/acts/ad-p166-9-generator-circuit-modification/history","analysis":"/api/acts/ad-p166-9-generator-circuit-modification/analysis","conflicts":"/api/acts/ad-p166-9-generator-circuit-modification/conflicts","importantCases":"/api/acts/ad-p166-9-generator-circuit-modification/important-cases","documents":"/api/acts/ad-p166-9-generator-circuit-modification/documents"}}