{"id":"F2006B07350","name":"AD/TB20/44 - MLG Hinged Strut","slug":"ad-tb20-44-mlg-hinged-strut","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49445,"registerId":"commonwealth-F2006B07350-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\nAerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/TB20/44 MLG Hinged Strut 12/2003 DM","sectionType":"part","heading":"AD/TB20/44 MLG Hinged Strut 12/2003 DM","content":"# AD/TB20/44 MLG Hinged Strut 12/2003 DM\n\nApplicability: Model TB 20 and TB 21 aircraft, serial numbers 1 through 2208 that have accumulated less than 50 flight hours or 50 landings, whichever occurs first, since delivery or since hinged strut or lower half-leg replacement; and\n\nHinged struts and lower half-legs supplied as spares until 15 September 2003.\n\nRequirement: Action in accordance with Socata Service Bulletin TB No. 10-139, dated September 2003.\n\nNote: DGAC AD 2003-390(A) refers.\n\nCompliance: Within 5 flight hours after 22 October 2003.\n\nThis Airworthiness Directive becomes effective on 22 October 2003.\n\nBackground: Reports were received of two cases of uncrimping of the bearing that connects the landing gear hinged strut to the landing gear leg.\n\n![Signature of David Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 14 October 2003\n\n![](image.001.png)","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD limits its scope to early‑life aircraft and specifically dated spares to address the reported uncrimping incidents. The applicability, remedial action (service bulletin) and short compliance time are consistent with a targeted safety correction rather than an expansion of regulatory reach."},"complexity_factors":["Narrow applicability: specific models (TB20/TB21), serial range (1–2208) and early‑life criterion (<50 flight hours or 50 landings).","Single mandatory action but implemented by following an external document (Socata Service Bulletin TB No. 10‑139), creating dependency on that document for procedural detail.","Very short compliance window (within 5 flight hours after 22 Oct 2003), increasing operational disruption and urgency for owners/operators.","Includes both aircraft in service and spare parts supplied until a cut‑off date, extending effect beyond installed equipment.","Legal basis referenced (CASR subreg. 39.1(1)) is singular and direct, reducing regulatory layering."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Aerospatiale (Socata) TB20 and TB21 aeroplanes (serials 1–2208) with less than 50 flight hours or 50 landings since delivery or since hinged strut/lower half‑leg replacement — and specified spare hinged struts/lower half‑legs supplied until 15 September 2003 — to carry out the work described in Socata Service Bulletin TB No. 10‑139. Compliance must occur within 5 flight hours after 22 October 2003. CASA issued the AD under CASR subreg. 39.1(1) after reports of two bearing uncrimping incidents; operators pay for and arrange the inspections/repairs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical defect in a specific aircraft model. It has not expanded beyond its original purpose of correcting the uncrimping bearing issue."},"complexity_factors":["Single, clearly defined applicability condition (serial number range plus flight hours/landings threshold)","Only one substantive requirement (compliance with referenced service bulletin)","No defined terms section","No cross-references to other legislation beyond a single note about a French aviation authority directive","Simple temporal compliance requirement (within 5 flight hours of effective date)","Short document length (approximately 200 words of substantive text)"],"plain_english_summary":"This safety order requires owners/operators of Socata TB20 and TB21 aeroplanes (serials 1–2208) to inspect and repair the hinged-strut bearing on the main landing gear — and also covers hinged strut/lower half-leg spare parts supplied before 15 Sept 2003. It applies only where the aircraft has flown less than 50 hours or made fewer than 50 landings since delivery or since those components were replaced.\n\nWork must follow Socata Service Bulletin TB No. 10-139 (Sept 2003) and be done within 5 flight hours after 22 Oct 2003 to prevent possible landing-gear failure."},"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-tb20-44-mlg-hinged-strut","history":"/api/acts/ad-tb20-44-mlg-hinged-strut/history","analysis":"/api/acts/ad-tb20-44-mlg-hinged-strut/analysis","conflicts":"/api/acts/ad-tb20-44-mlg-hinged-strut/conflicts","importantCases":"/api/acts/ad-tb20-44-mlg-hinged-strut/important-cases","documents":"/api/acts/ad-tb20-44-mlg-hinged-strut/documents"}}