{"id":"F2006B07355","name":"AD/TB20/9 - Main Landing Gear Bay","slug":"ad-tb20-9-main-landing-gear-bay","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49461,"registerId":"commonwealth-F2006B07355-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/9 - Main Landing Gear Bay","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/TB20/9 Main Landing Gear Bay 7/87\n\nApplicability: All models S/Nos 275 to 709.\n\n \n\nRequirement: Action in accordance with Aerospatiale Socata SB No 30.\n\n \n\nNote: Bureau Veritas AD 87-030(A) refers.\n\n \n\nCompliance: At the next scheduled inspection for Maintenance Release issue after 30 June 1987.\n\n \n\nBackground: The manufacturer reports the possibility of the main landing gear contacting the landing gear bay structure.\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\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, single-issue safety directive focused solely on the landing gear bay inspection. It has not expanded beyond its original purpose."},"complexity_factors":["Extremely short document (under 200 words)","Only one substantive requirement: comply with an external technical document (Service Bulletin No. 30)","Simple applicability test (serial number range)","Single compliance deadline tied to existing maintenance schedule","No defined terms, no cross-references to other legislation, no conditional logic or exceptions"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety notice for aircraft owners and operators.\n\n**What it does:** Requires owners of specific Socata TB20 Trinidad aeroplanes to inspect or fix a problem with the main landing gear bay (the compartment where the wheels fold up). The manufacturer found that the landing gear might hit and damage the surrounding structure.\n\n**Who it affects:** Anyone who owns or operates a Socata TB20 aircraft with serial numbers 275 through 709.\n\n**What they must do:** Follow the manufacturer's Service Bulletin No. 30 (a technical instruction document) to check or repair the gear bay. This must be done at the next routine maintenance check after 30 June 1987.\n\n**Why it matters:** If the landing gear contacts the bay structure, it could cause damage that might lead to gear failure — potentially causing a crash on landing. This rule ensures the problem is caught and fixed before it becomes dangerous."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Based on the text provided, there is no indication the instrument’s scope was altered from its stated purpose. The AD explicitly applies to TB20 serial numbers 275–709 and mandates action per SB No 30 at the next scheduled Maintenance Release inspection after 30 June 1987. The document’s applicability, requirement, timing, and stated background are internally consistent and do not show any expansion or narrowing beyond the stated serial-number range and timing constraint (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Direct cross-reference to an external technical document (Aerospatiale Socata SB No 30), requiring consultation of that bulletin for operational detail (Requirement).","Specific applicability limited to a serial-number range, which requires owner/operators to verify affected aircraft (Applicability).","Timing tied to the next scheduled Maintenance Release inspection after a specific date, creating a narrow scheduling rule rather than an immediate mandate (Compliance).","Cross-reference to an external authority’s AD (Bureau Veritas AD 87-030(A)), which may require coordination or checking for consistency (Note).","AD text supplies the requirement but not the technical steps; operational implementation relies on maintenance organisations to interpret and execute the SB (Requirement)."],"plain_english_summary":"The AD mandates that Aerospatiale (Socata) TB20 (Trinidad) aeroplanes serials 275–709 be inspected and any corrective work performed per Aerospatiale Service Bulletin No. 30 at the next Maintenance Release inspection after 30 June 1987. It was issued because the manufacturer reported possible contact between the main landing gear and the gear bay structure. Compliance is mandatory for owners/operators, who bear the costs and schedule the work with approved maintenance providers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-9-main-landing-gear-bay","history":"/api/acts/ad-tb20-9-main-landing-gear-bay/history","analysis":"/api/acts/ad-tb20-9-main-landing-gear-bay/analysis","conflicts":"/api/acts/ad-tb20-9-main-landing-gear-bay/conflicts","importantCases":"/api/acts/ad-tb20-9-main-landing-gear-bay/important-cases","documents":"/api/acts/ad-tb20-9-main-landing-gear-bay/documents"}}