{"id":"F2006B07348","name":"AD/TB20/42 - Nose and Main Landing Gear Actuator","slug":"ad-tb20-42-nose-and-main-landing-gear-actuator","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49439,"registerId":"commonwealth-F2006B07348-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\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\nAerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/TB20/42 Nose and Main Landing Gear Ac","sectionType":"part","heading":"AD/TB20/42 Nose and Main Landing Gear Actuator 3/2003","content":"# AD/TB20/42 Nose and Main Landing Gear Actuator 3/2003\n\nApplicability: Model TB20 and TB21 aircraft, serial numbers 275 through 2130 inclusive, 2132 through 2136 inclusive, 2138 through 2154 inclusive, 2157 through 2162 inclusive,\n\nand 2170.\n\nRequirement: 1. Carry out an inspection of the nose and main landing gear cylinder end fittings in accordance with Socata Service Bulletin 10-133-32.\n\n2. Carry out a re-torque of the nose and main landing gear cylinder end fittings in accordance with Socata Service Bulletin 10-133-32.\n\nNote: DGAC AD 2002-574(A) refers.\n\nCompliance: 1. Unless previously carried out, during the next 50 hourly scheduled inspection but no later than 31 May 2003.\n\n2. Unless previously carried out, during the next 100 hourly scheduled inspection but no later than 30 December 2003.\n\nThis Airworthiness Directive becomes effective on 20 March 2003.\n\nBackground: Insufficient torque on the landing gear actuator end fitting may lead to failure of the actuator and uncommanded extension of the landing gear. This Directive requires checking of the end fitting for security followed by a re-torque of the actuator end fitting to prevent failure of the actuator.\n\n![Signature of James Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 28 January 2003\n\n![](image.001.png)","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD stays within the stated safety objective: it targets landing-gear actuator end fittings on listed TB20/TB21 serial numbers and mandates inspection and re-torque. It does not broaden to other components or aircraft beyond the Applicability, nor add measures beyond those in the Requirement and Compliance sections (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Narrow applicability: specific serial-numbered TB20/TB21 aircraft only (Applicability).","Simple, short list of required tasks: inspection and re-torque per Socata Service Bulletin 10-133-32 (Requirement).","Clear, short compliance windows: next 50/100-hour scheduled inspections or specified calendar dates (Compliance).","Dependence on an external technical document for the method and acceptance criteria (Socata Service Bulletin 10-133-32) (Requirement).","Regulatory enforcement and record-keeping implied by CASA AD mechanism (Compliance; effective date noted).","Safety rationale explicitly stated: insufficient torque may cause actuator failure and uncommanded gear extension (Background)."],"plain_english_summary":"Mechanically, this Airworthiness Directive requires owners/operators of specified Socata TB20/TB21 serial-numbered aircraft to inspect and re-torque nose and main landing gear actuator end fittings per Socata Service Bulletin 10-133-32 to prevent actuator failure and uncommanded gear extension (Background). CASA mandates deadlines tied to the next 50/100-hour inspections or fixed dates. Owners/operators pay for the work, must adjust maintenance schedules, and record compliance; the rule replaces voluntary maintenance choice with a regulatory obligation."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific mechanical defect in specific aircraft models. The scope remains tightly focused on the landing gear actuator torque issue as originally identified. No scope creep is evident."},"complexity_factors":["Very short document (approximately 300 words)","Only 2 substantive requirements with clear, sequential numbering","Single interpretation issue: defined applicability by specific serial number ranges","Simple temporal compliance structure (two deadlines tied to flight hours or calendar dates)","No nested exceptions, conditional logic, or cross-references to other legislation beyond a single reference to a French authority document and manufacturer service bulletin","Plain language background section explaining the safety rationale"],"plain_english_summary":"This Airworthiness Directive requires owners and operators of certain Socata TB20 and TB21 aeroplanes to inspect and re-torque the nose and main landing‑gear actuator end fittings to eliminate a risk of fittings coming loose.  \n\nIt targets affected aircraft and maintenance engineers because loose actuator fittings could let the gear drop unexpectedly in flight; the AD took effect 20 March 2003 and follows French DGAC and manufacturer guidance."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator","history":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator/history","analysis":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator/analysis","conflicts":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator/conflicts","importantCases":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator/important-cases","documents":"/api/acts/ad-tb20-42-nose-and-main-landing-gear-actuator/documents"}}