{"id":"F2006B10793","name":"AD/IAI-W/18 Amdt 1 - Horizontal Stabiliser Trim Actuator","slug":"ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56258,"registerId":"commonwealth-F2006B10793-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/IAI-W/18 Amdt 1 - Horizontal Stabiliser Trim Actuator","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nIsrael Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes\n\nAD/IAI-W/18\n\nAmdt 1\n\n  \nHorizontal Stabiliser Trim Actuator 3/98\n\nApplicability: Models 1124 and 1124A aircraft, all serial numbers.\n\nRequirement 1. Action in accordance with Israel Aircraft Industries Service Bulletin 1124-27-133.\n\n2. Overhaul and replace the Horizontal Stabiliser Trim Actuator in accordance with Israel Aircraft Industries Service Bulletin 1124-27-136.\n\nNote 1. Replacement of the Trim Actuator in accordance with Requirement 2, constitutes terminating action for the Requirement 1 inspections of this Directive.\n\nNote 2. Israel CAA AD 27-97-09-02 and AD 96-92 refer.\n\nCompliance: 1. Aircraft and actuators:\n\n    \\- which have achieved either 6,000 landings, or 2,000 landings respectively, irrespective of whichever occurred first, within 50 hours time in service after 2 October 1996; or,\n\n    \\- with less than both 6,000 landings and 2,000 landings respectively, at the next inspection for maintenance release issue after 2 October 1996.\n\n    \\- thereafter as per the requirement of Maintenance Manual Chapter 5.\n\n2. Unless already accomplished, before 26 August 1999.\n\nThe compliance of Requirement 1 remains unchanged from the initial issue of this directive.\n\nThis amendment becomes effective on 26 February 1998.\n\nBackground: During an inspection, an operator found one horizontal stabiliser jackscrew sheared, causing the rod end to separate from the jackscrew.\n\nAmendment 1 is issued in response to a new CAAI AD which initiates a program for removal from service of units of expired fatigue life and of unknown history, and replacement by new, life controlled jackscrews.\n\nThe original issue of this airworthiness directive became effective on 7 November 1996.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose — addressing the horizontal stabiliser trim actuator safety issue in Westwind aircraft. Amendment 1 simply updates the compliance requirements to align with a new Israeli aviation authority directive, adding the fatigue life and unknown history removal program. It does not expand to other aircraft types, components, or operational matters beyond the specific jackscrew/actuator problem identified in the original 1996 directive."},"complexity_factors":["Short, single-purpose document (2 requirements plus notes)","Only 4 defined applicability terms (specific aircraft models and serial numbers)","Simple conditional logic for compliance timing (landing counts vs. calendar dates)","Cross-references to 2 external service bulletins and 2 Israeli CAA directives, but these are cited rather than incorporated by complex textual reference","No nested definitions or interpretive provisions","Clear terminating action specified (Requirement 2 satisfies Requirement 1)"],"plain_english_summary":"This mandatory CASA AD requires owners/operators and maintenance organisations of Israel Aircraft Industries Westwind 1124/1124A aircraft to inspect — and ultimately replace — the horizontal stabiliser trim actuator after discovery of a sheared jackscrew. The measure prevents stabiliser malfunction and potential loss of control by removing actuators at or beyond their fatigue life (or with unknown history) and replacing them with tracked, overhauled units; replacement is the terminating action."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 1 adds a mandatory overhaul/replacement requirement (Requirement 2) to remove jackscrews of expired fatigue life or unknown history and to fit new life-controlled jackscrews; replacement is defined as terminating action for the prior inspection regime (Requirement 1). The amendment therefore expands the directive from inspection-only action to a removal-and-replace program, while leaving Requirement 1’s original inspection details unchanged."},"complexity_factors":["Technical subject-matter (jackscrew fatigue, overhaul and life-controlled replacement) requiring specialised maintenance and parts","References two manufacturer Service Bulletins (1124-27-133 and 1124-27-136) for required actions","Cross-references to foreign regulator ADs (Israel CAA AD 27-97-09-02 and AD 96-92)","Multiple and overlapping compliance triggers and deadlines (landing-count thresholds, 50 hours time-in-service after 2 Oct 1996, next inspection for maintenance release, and an overall deadline before 26 Aug 1999)","Ambiguous phrasing in the compliance thresholds (the text refers to “either 6,000 landings, or 2,000 landings respectively, irrespective of whichever occurred first”), increasing interpretive burden","Applies to all serial numbers of two models, increasing fleet-wide operational impact","Interaction between inspection requirement and terminating action on replacement requires record-keeping and administrative tracking","Procurement and scheduling burdens for operators to obtain life-controlled jackscrews and complete overhauls within deadlines"],"plain_english_summary":"This airworthiness directive requires operators of IAI Westwind 1124/1124A aircraft to carry out inspections per IAI Service Bulletin 1124‑27‑133 and to overhaul or replace the horizontal stabiliser trim actuator per Service Bulletin 1124‑27‑136; replacing the actuator ends the inspection requirement. It applies to all serial numbers and sets specific landing-count and timing triggers plus a final compliance date.\n\nThe directive says the change aims to remove jackscrews past fatigue life or with unknown history. Operators pay for inspections, overhauls or replacements, must track landings and maintenance records, and manage procurement and scheduling to meet the deadlines and referenced bulletins."}},"importantCases":[],"_links":{"self":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator","history":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator/history","analysis":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator/analysis","conflicts":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator/conflicts","importantCases":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator/important-cases","documents":"/api/acts/ad-iai-w-18-amdt-1-horizontal-stabiliser-trim-actuator/documents"}}