{"id":"F2006B11167","name":"AD/LJ45/6 - Horizontal Stabiliser Actuator Assembly","slug":"ad-lj45-6-horizontal-stabiliser-actuator-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56864,"registerId":"commonwealth-F2006B11167-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nLearjet 45 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/LJ45/6 Horizontal Stabiliser Actuator","sectionType":"part","heading":"AD/LJ45/6 Horizontal Stabiliser Actuator Assembly 10/2003","content":"# AD/LJ45/6 Horizontal Stabiliser Actuator Assembly 10/2003\n\nTX\n\nApplicability: All Learjet Model 45 series aeroplanes fitted with Horizontal Stabilizer Actuator Assembly (HSAA) Part Number (P/N) 6627401000-005.\n\nRequirement: 1. Remove from service HSAA P/N 6627401000-005.\n\n2. Do not install HSAA P/N 6627401000-005 on any aeroplane as a replacement part.\n\nNote 1: FAA AD 2003-16-19 Amdt 39-13272 refers.\n\nNote 2: At the time of this Directive there are no replacement HSAA’s approved for fitment to the aeroplane.\n\nNote 3: AD/LJ45/5 required fitment of HSAA P/N 6627401000-005 as a replacement part for P/N 6627401000-001 or 2A9200F HSAA’s. This Directive augments those requirements.\n\nCompliance: For Requirement 1: Before further flight as of the effective date of this Directive.\n\nFor Requirement 2: As of the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 15 August 2003.\n\nBackground: The HSAA P/N 6627401000-005 was not manufactured to the type design data. A brittle fracture could occur on the acme screw and nut within the assembly that could result in a loss of control of the aeroplane.\n\n![Signature of Jim Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 14 August 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 15 August 2003.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope: addressing a specific unsafe condition in a specific aircraft part. It does not expand beyond the immediate safety issue. The reference to the prior directive AD/LJ45/5 is clarifying context rather than scope creep — it explains the regulatory history without adding new obligations beyond the immediate removal and prohibition."},"complexity_factors":["Very short document (approximately 300 words)","Only 2 substantive requirements with clear, unconditional language","Single defined term (HSAA = Horizontal Stabilizer Actuator Assembly) explained in context","No nested exceptions or conditional logic — requirements apply universally to all affected aircraft","Simple compliance structure: immediate action required, no phased implementation","Cross-reference to one prior directive (AD/LJ45/5) and one FAA directive, but these are explanatory rather than operational dependencies"],"plain_english_summary":"This AD orders immediate removal and permanent ban of Horizontal Stabilizer Actuator Assembly P/N 6627401000-005 from all Learjet 45 series aeroplanes, grounding any aircraft with the part installed until it is removed. It affects Learjet 45 owners, operators, and maintenance organisations because the part was not built to approved design standards and can suffer brittle fracture of its screw/nut mechanism, risking loss of horizontal stabiliser control. It took effect 15 August 2003 and reverses a prior replacement mandate."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The Directive reverses the provisioning in AD/LJ45/5 (which required fitment of P/N 6627401000-005 as a replacement) by mandating removal and banning installation of that same P/N (Note 3; Requirement 1–2). This narrows permissible parts and eliminates a previously authorised replacement option."},"complexity_factors":["Narrow technical applicability — only Learjet 45 aeroplanes fitted with HSAA P/N 6627401000-005 (Applicability).","Immediate mandatory action — removal from service before further flight (Requirement 1; Compliance).","Absolute prohibition on future installation of the part (Requirement 2).","No approved replacement HSAA at time of directive, creating operational and sourcing pressure on operators (Note 2).","Interaction with prior and foreign directives — augments AD/LJ45/5 and refers to FAA AD 2003-16-19 (Note 3; Note 1).","Clear safety rationale tied to manufacturing non‑conformance and brittle fracture risk (Background)."],"plain_english_summary":"CASA requires removal from service of Horizontal Stabiliser Actuator Assembly P/N 6627401000-005 from all Learjet 45 aeroplanes and prohibits installing that part as a replacement. It affects operators and owners who must remove the part before further flight and bear any grounding or replacement costs. The Directive cites a manufacturing non‑conformity and risk of brittle fracture that could cause loss of control, and is enforced by the CASA delegate (Requirement 1; Compliance)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly","history":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly/history","analysis":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly/analysis","conflicts":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly/conflicts","importantCases":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly/important-cases","documents":"/api/acts/ad-lj45-6-horizontal-stabiliser-actuator-assembly/documents"}}