{"id":"F2006B11439","name":"AD/P166/11 - Main Landing Gear Retracting Jack Stem - Installation of Washer","slug":"ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57375,"registerId":"commonwealth-F2006B11439-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P166/11 - Main Landing Gear Retracting Jack Stem - Installation of Washer","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/P166/11 Main Landing Gear Retracting NK\n\nJack Stem - Installation of Washer\n\nApplicability: S/Nos. prior to 372. Document: Piaggio SB P166-1. 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","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical component on a specific aircraft model. It has not expanded beyond its original purpose of mandating a particular hardware modification."},"complexity_factors":["Extremely short document — approximately 100 words of substantive content","Only one operative requirement (install washer)","Simple applicability test (serial number threshold)","Single cross-reference to manufacturer service bulletin","No defined terms, no conditional logic, no exceptions","Standard regulatory template format with minimal variation"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Piaggio P166 series aircraft** (a type of Italian-made twin-engine plane).\n\n**What it requires:**\n- Aircraft owners/operators must install a washer on the **main landing gear retracting jack stem** — a mechanical component that helps raise and lower the wheels.\n- This applies only to aircraft with **serial numbers prior to 372**.\n\n**Why it matters:**\n- Landing gear failures can be catastrophic. This directive addresses a specific mechanical defect or wear issue identified by the manufacturer (Piaggio) in their Service Bulletin P166-1.\n- The word **\"Forthwith\"** means this fix must be done **immediately** — before the next flight, not at the next scheduled maintenance.\n\n**Who must comply:**\n- Anyone operating a Piaggio P166 with the affected serial numbers in Australian airspace."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive applies to Piaggio P166 aeroplanes with serial numbers prior to 372 and mandates the washer installation per Piaggio SB P166-1 with immediate effect. The instrument's scope, as expressed in the text provided, is a targeted, serial-number-limited corrective action; there is no indication in the text that the scope differs from that targeted corrective intent."},"complexity_factors":["Narrow technical scope: single, specific modification (installation of a washer on a single component). (AD title)","Clear applicability: limited to aircraft with serial numbers prior to 372, reducing coverage ambiguity. (Applicability: S/Nos. prior to 372)","Prescribed method: compliance references a single manufacturer service bulletin, concentrating technical instructions in one document. (Document: Piaggio SB P166-1)","Immediate timing increases operational urgency but not technical complexity. (Compliance: Forthwith)","Dependence on supply and maintenance availability introduces practical but not legal complexity. (Document: Piaggio SB P166-1)","No multiple compliance options or staged inspections specified, lowering procedural complexity. (AD text)"],"plain_english_summary":"### What this directive does, in plain terms\n\n- It requires the installation of a washer on the jack stem of the main landing gear on Piaggio P166 series aeroplanes (AD/P166/11: \"Main Landing Gear Retracting NK — Jack Stem - Installation of Washer\"). (see AD title)\n- It applies only to aeroplanes with serial numbers prior to 372. (Applicability: S/Nos. prior to 372)\n- The work and any associated instructions are those set out by the manufacturer in Piaggio Service Bulletin P166-1. (Document: Piaggio SB P166-1)\n- The timing required is immediate — operators must comply \"forthwith.\" (Compliance: Forthwith)\n\n### Who is affected\n\n- Owners and operators of Piaggio P166 aeroplanes with serial numbers earlier than 372. They are the parties responsible for arranging and paying for the modification and any downtime while it is done. (Applicability: S/Nos. prior to 372; Compliance: Forthwith)\n- Maintenance organisations and mechanics who will perform the washer installation in accordance with the Piaggio service bulletin. (Document: Piaggio SB P166-1)\n\n### Why it matters (stated purpose and how it operates)\n\n- The directive requires a specific physical modification (adding a washer to the jack stem) to aircraft in the stated serial number range. Mechanically, the action is: follow Piaggio SB P166-1 and install the specified washer on the main landing gear jack stem. (AD title; Document: Piaggio SB P166-1)\n- The directive is issued as an airworthiness requirement; the stated rationale for such directives is to address an identified technical deficiency affecting safe operation. This document instructs compliance without delay. (Compliance: Forthwith)\n\n### Practical consequences, costs and incentives\n\n- Direct costs: owners/operators pay for the part(s) (the washer), labour to perform the installation, and any aircraft downtime while the work is completed. (Applicability; Document; Compliance)\n- Operational impact: because compliance is required forthwith, affected aircraft may be grounded or out of service until the installation is complete, producing schedule and revenue effects for commercial operators or availability impacts for private owners. (Compliance: Forthwith)\n- Supply and delivery risk: the directive points to the manufacturer’s service bulletin for the technical steps; timely compliance depends on access to the specified part and to a maintenance provider able to perform the work per the bulletin. (Document: Piaggio SB P166-1)\n- Administrative/compliance burden: operators must arrange the modification and retain records demonstrating the work followed Piaggio SB P166-1, as required by typical airworthiness directive practice. The AD itself sets the legal requirement; the SB provides the method. (AD title; Document: Piaggio SB P166-1)\n\n### Decision and discretion\n\n- The regulatory requirement is set by the Civil Aviation Safety Authority via this AD; the method of compliance referenced is the manufacturer’s service bulletin, so technical discretion about how to perform the installation is limited to what the bulletin specifies. (Document: Piaggio SB P166-1)\n- Maintenance providers will exercise technical judgment only to the extent permitted by the service bulletin and applicable maintenance regulations. (Document: Piaggio SB P166-1)\n\n### Trade-offs, substitution effects and implementation risks\n\n- Trade-offs: the immediate safety-related objective (install washer) is traded against the cost and downtime incurred by operators who must comply forthwith. (Compliance: Forthwith)\n- Substitution effects: operators may need to reallocate maintenance slots, source replacement parts, or use different aircraft while affected units are unavailable. (Applicability; Compliance)\n- Implementation risks: delays in part supply, uncertainty about whether prior repairs or modifications affect the required installation, and variability in maintenance quality could affect how quickly and effectively the issue is resolved. (Document: Piaggio SB P166-1)\n\n### Concrete who-pays / who-decides statement\n\n- Who pays: the aircraft owner/operator pays for parts, labour and downtime. (Applicability; Document; Compliance)\n- Who decides: the regulator (Civil Aviation Safety Authority) issues the requirement; the manufacturer’s service bulletin provides the technical method; maintenance organisations implement the work. (AD title; Document: Piaggio SB P166-1)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer","history":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer/history","analysis":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer/analysis","conflicts":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer/conflicts","importantCases":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer/important-cases","documents":"/api/acts/ad-p166-11-main-landing-gear-retracting-jack-stem-installation-of-washer/documents"}}