{"id":"F2006B02391","name":"AD/AMD 50/24 - Composite Horizontal Stabiliser","slug":"ad-amd-50-24-composite-horizontal-stabiliser","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41621,"registerId":"commonwealth-F2006B02391-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \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 CAR 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\nAMD Falcon 50 and 900 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/AMD 50/24 Composite Horizontal Stabil","sectionType":"part","heading":"AD/AMD 50/24 Composite Horizontal Stabiliser 4/2002","content":"# AD/AMD 50/24 Composite Horizontal Stabiliser 4/2002\n\nApplicability: All Mystere Falcon 900 and Falcon 900EX aircraft, which have Dassault Aviation modification M2460 incorporated, except aircraft which have modification M3463 incorporated.\n\nAll Falcon 2000 aircraft which have modification M1283 incorporated, except aircraft which have modification M2092 incorporated.\n\nRequirement: Action in accordance with Dassault Aviation Service Bulletins F900-291, F900EX- 155, or F2000-234, as applicable.\n\nNote: DGAC AD 2002-089(B) refers.\n\nCompliance: Within 7 months after 18 April 2002.\n\nThis Airworthiness Directive becomes effective on 18 April 2002.\n\nBackground: Lightning tests on a composite horizontal stabiliser have indicated that excess paint thickness is detrimental to lightning spreading. This excess paint thickness may lead to serious damage in the case of a direct lightning strike on sensitive areas.\n\n![](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 March 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 March 2002.","sortOrder":1}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with narrow, specific scope targeting particular aircraft configurations with a known safety defect. No scope creep evident."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined applicability conditions (aircraft models plus modification exceptions)","Single requirement referencing external technical documents (service bulletins)","No nested conditional logic or cross-references to other legislation","Straightforward compliance deadline (fixed date plus 7 months)","Background explanation is plain language and technical but not legally complex"],"plain_english_summary":"This CASA safety order requires owners/operators of certain Dassault Falcon business jets to inspect/repair the composite horizontal stabiliser where excess paint can prevent safe lightning current flow. It applies to specific Falcon 900/900EX and 2000 aircraft with particular factory modifications (unless later mods are fitted) and mandates compliance with Dassault service bulletins within seven months of 18 April 2002. It prevents potentially catastrophic lightning damage."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD stays within the original, narrow safety purpose set out in the background: to correct an unsafe condition on the composite horizontal stabiliser related to lightning protection. It targets specified Falcon variants and either requires the service-bulletin actions or exempts aircraft that already have the later modifications. It does not expand beyond that technical remedy or add unrelated regulatory obligations."},"complexity_factors":["Short, single-issue AD focused on one component (composite horizontal stabiliser)","Limited applicability with simple conditional exclusions (applies where M2460 or M1283 is incorporated; excludes aircraft with M3463 or M2092)","References to three manufacturer Service Bulletins (F900-291, F900EX-155, F2000-234) rather than full technical text (operator must follow those documents)","Fixed single compliance window (7 months after 18 April 2002) and a clear effective date","Cross-reference to a foreign AD (DGAC AD 2002-089(B)) but no extensive inter‑regulatory matrix","No nested exceptions beyond the single pair of exclusions per aircraft family"],"plain_english_summary":"**What this Airworthiness Directive (AD) does — mechanically**\n\n- **Requires** certain Dassault Falcon aeroplanes to have the composite horizontal stabiliser checked and corrected in accordance with specific Dassault Service Bulletins (F900-291, F900EX-155, or F2000-234), as applicable.  (See \"Requirement\".)\n- **Applies to**: Mystere Falcon 900 and Falcon 900EX aircraft that have Dassault modification M2460 incorporated, except those already modified by M3463. Also applies to Falcon 2000 aircraft that have modification M1283 incorporated, except those already modified by M2092. (See \"Applicability\".)\n- **Deadline**: work must be carried out within 7 months after 18 April 2002. The AD became effective on 18 April 2002. (See \"Compliance\".)\n\n**Why the rule exists (stated reason)**\n\n- The AD cites lightning tests showing that excess paint thickness on a composite horizontal stabiliser reduces the stabiliser's ability to spread lightning currents. That condition can allow a concentrated lightning current to damage sensitive areas; the AD requires corrective action specified by the manufacturer to address that unsafe condition. (See \"Background\".)\n\n**Who decides and who pays**\n\n- The Civil Aviation Safety Authority (CASA) delegate issued the AD and sets the mandatory requirement and compliance timeframe. Operators (aircraft owners or their maintenance organisations) are responsible for performing the work and paying for parts, labour and any downtime. Maintenance organisations will typically implement the service-bulletin actions. (Requirement; Compliance.)\n\n**What operators must do in practice**\n\n- Identify whether an individual aircraft falls inside the AD's applicability (check whether M2460 or M1283 is incorporated and whether M3463 or M2092 is not). If the aircraft is covered, arrange for the actions described in the applicable Dassault Service Bulletin to be completed within the 7‑month window. If an aircraft already has the listed follow-up modification (M3463 or M2092), no further action under this AD is required.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs to operators: inspections, corrective work specified in the service bulletins (which may include removal of excess paint, repairs, or installation of lightning protection measures), parts, and labour; aircraft downtime while work is carried out. These are immediate, concentrated costs on affected operators.\n- Benefit: reduced risk of lightning strike damage to the stabiliser and associated safety risk. This is the safety rationale the AD advances.\n- Incentives: operators have a regulatory incentive to comply within the timeframe to keep aircraft airworthy; operators who previously fitted the later modification (M3463 or M2092) are exempt, so early adopters avoid the immediate compliance cost.\n- Implementation risk and administrative burden: compliance depends on following manufacturer service bulletins; clarity and completeness of those bulletins affect how quickly work can be done. Scheduling work within the fixed 7‑month period can strain maintenance capacity and create opportunity costs (lost revenue from aircraft downtime).\n- Effect on market/commercial activity: the AD does not alter ownership, routes, or pricing directly, but maintenance costs and grounded time may affect an operator's short‑run productivity and operating costs. Work may concentrate business with authorized Dassault maintenance providers if the service bulletins require specialised procedures or materials.\n\n**Mechanics of enforcement and options**\n\n- The AD is enforceable under the Civil Aviation Regulations regime; operators must comply or obtain an approved alternative corrective action through the regulator. The document references a corresponding DGAC (French authority) AD, indicating the manufacturer and multiple regulators addressed the same unsafe condition.\n\n**Net practical effect**\n\n- A narrow, technically focused safety mandate: affected Falcon 900/900EX/2000 aeroplanes must be inspected and corrected per Dassault's service instructions within the specified period unless they already incorporate the later listed modifications that remove them from applicability. The regulator sets the deadline and enforces compliance; operators bear the costs and manage the maintenance scheduling.\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser","history":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser/history","analysis":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser/analysis","conflicts":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser/conflicts","importantCases":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser/important-cases","documents":"/api/acts/ad-amd-50-24-composite-horizontal-stabiliser/documents"}}