{"id":"F2006B11440","name":"AD/P166/12 - Elevator Trim Tab Inner Hinge - Modification","slug":"ad-p166-12-elevator-trim-tab-inner-hinge-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57377,"registerId":"commonwealth-F2006B11440-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P166/12 - Elevator Trim Tab Inner Hinge - 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/P166/12 Elevator Trim Tab Inner Hinge - Modification 9/61\n\nApplicability: S/Nos. prior to 379. Document: Piaggio SB P166-6. 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":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive for a specific aircraft component. It has not expanded beyond its original purpose of addressing the elevator trim tab hinge issue on early-production Piaggio P166 aircraft. The scope remains precisely as intended when first issued."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — all language is plain technical aviation terminology","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Single, unambiguous compliance requirement ('Forthwith') with no conditional logic or exceptions","Simple applicability test based solely on aircraft serial number","Refers to external technical document (Piaggio SB P166-6) for actual implementation details, keeping the AD itself minimal"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft.\n\n**What it does:**\n- Requires owners/operators of **Piaggio P166 series aeroplanes** (specifically those with serial numbers before 379) to modify the **elevator trim tab inner hinge**.\n- The elevator trim tab is a small movable surface on the tail of the plane that helps control the aircraft's pitch (nose up/down). The inner hinge is part of its mounting mechanism.\n- The modification must be done **\"forthwith\"** — meaning immediately, without delay.\n\n**Who it affects:**\n- Owners and operators of Piaggio P166 aircraft with serial numbers 378 and below.\n- Maintenance organisations servicing these aircraft.\n\n**Why it matters:**\n- Airworthiness Directives are issued when a safety defect is discovered that could affect flight safety. This suggests there was a problem with the original hinge design that could potentially lead to control issues.\n- Compliance is **mandatory** — you cannot legally fly the aircraft until this is done.\n\n**How to comply:**\n- Follow the instructions in **Piaggio Service Bulletin P166-6** (the manufacturer's official technical notice).\n- The reference \"9/61\" likely indicates this directive was originally issued in September 1961, showing this is a long-standing safety requirement."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument itself contains no statement that it changes scope from an earlier instrument or intent. It sets a single, specific requirement: modify the elevator trim tab inner hinge on Piaggio P166 aircraft with serial numbers prior to 379, per Piaggio SB P166-6, with compliance required forthwith. There is no textual indication within the instrument that the applicability or required action has been expanded or narrowed from a prior version."},"complexity_factors":["Narrow and clearly defined applicability (serial numbers prior to 379) reduces scope complexity. (Applicability)","Compliance timing is terse and urgent — stated only as \"Forthwith\" — creating operational ambiguity about scheduling and prioritisation. (Compliance)","Technical details are delegated entirely to an external document (Piaggio SB P166-6), so legal text is simple but practical compliance depends on that separate technical source. (Document)","No alternative compliance paths, exemptions or staged deadlines are provided, increasing practical rigidity. (Compliance)","Instrument lacks details on parts, estimated labour, or approved maintenance providers, leaving implementation planning to operators and maintainers. (Document)"],"plain_english_summary":"The AD requires an immediate (forthwith) physical modification to the elevator trim tab inner hinge on Piaggio P166 aeroplanes with serial numbers before 379, to be carried out in accordance with Piaggio Service Bulletin P166‑6. Owners/operators of those aircraft bear the parts, labour and downtime costs; the Civil Aviation Safety Authority enforces the mandatory requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification","history":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification/history","analysis":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification/analysis","conflicts":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification/conflicts","importantCases":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification/important-cases","documents":"/api/acts/ad-p166-12-elevator-trim-tab-inner-hinge-modification/documents"}}