{"id":"F2006B07313","name":"AD/TB20/10 - Nose Landing Gear Hydraulic Line","slug":"ad-tb20-10-nose-landing-gear-hydraulic-line","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49330,"registerId":"commonwealth-F2006B07313-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/10 - Nose Landing Gear Hydraulic Line","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\n \n\nAD/TB20/10 Nose Landing Gear Hydraulic Line 11/87\n\nApplicability: To all model TB20 and TB21 aircraft with S/Nos up to and including 760. Aircraft S/Nos. 643, 644, 752 and 753 are excluded from the requirements of this AD.\n\n \n\nRequirement: Relocate L/H nose gear undercarriage hydraulic pipe in accordance with Aerospatiale Socata SB No.34.\n\n \n\nNote: Bureau veritas AD 87-117(A) refers.\n\n \n\nCompliance: Next scheduled inspection for maintenance release issue after 30 October 1987.\n\n \n\nBackground: The manufacturer has reported chafing of the L.H. nose gear hydraulic line by the rudder control rod. If the chafed line developed a leak a situation could occur where aircraft had to land with its undercarriage not locked down.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a limited aircraft population. It has not expanded beyond its original purpose of mandating a single design modification to prevent hydraulic line failure."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 defined elements: applicability (serial number range), requirement (single action), compliance deadline, and background","No cross-references to other legislation or regulations beyond a single note referencing a French authority document","Simple conditional logic: serial number range with explicit exclusions","Single mandatory action with no exceptions, alternatives, or tiered compliance pathways"],"plain_english_summary":"This CASA Airworthiness Directive mandates a one‑time relocation of a left‑side nose‑gear hydraulic pipe on certain Socata TB20 and TB21 aeroplanes (serials up to 760, excluding 643, 644, 752, 753).  \n\nThe pipe was found rubbing the rudder control rod, risking hydraulic leakage and improper nose‑wheel lock. Owners must follow the manufacturer’s Service Bulletin No. 34 at the next maintenance after 30 Oct 1987; the fix is permanent."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument sets a targeted corrective requirement for specified serial-numbered TB20/TB21 aircraft and does not indicate any expansion or reduction of scope from prior measures within the text; it adopts the manufacturer's remedy without adding broader applicability."},"complexity_factors":["Serial-number–based applicability and explicit exclusions require verification of individual airframe eligibility.","Technical work is delegated to an external document (Aerospatiale Socata SB No.34), so regulators reference but do not detail the method.","Compliance timing is tied to the next scheduled maintenance release after a specified date rather than an absolute deadline, creating scheduling discretion for operators.","Safety consequence is operational (potential failure of undercarriage lock), increasing urgency for affected operators despite limited regulatory detail.","Recordkeeping and maintenance-release procedures must reflect completion at inspection, imposing routine administrative steps on operators."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Aerospatiale (Socata) TB20 and TB21 aeroplanes (serial numbers up to 760, excluding S/Ns 643, 644, 752 and 753) to relocate the left‑hand nose‑gear hydraulic pipe in accordance with Aerospatiale Socata Service Bulletin No.34. \n\nCompliance is due at the next scheduled maintenance inspection after 30 October 1987; operators bear the cost and must schedule the modification to address reported chafing by the rudder control rod that could cause a hydraulic leak and an undercarriage not‑locked condition."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line","history":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line/history","analysis":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line/analysis","conflicts":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line/conflicts","importantCases":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line/important-cases","documents":"/api/acts/ad-tb20-10-nose-landing-gear-hydraulic-line/documents"}}