{"id":"F2006B07337","name":"AD/TB20/32 Amdt 1 - MLG Hinged Strut Attachment Bearings","slug":"ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49399,"registerId":"commonwealth-F2006B07337-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/32 Amdt 1 - MLG Hinged Strut Attachment Bearings","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\nAD/TB20/32\n\nAmdt 1\n\n  \nMLG Hinged Strut Attachment Bearings 5/99\n\nApplicability: Models TB20 and TB21 S/nos 1 to 9999.\n\nRequirement: Action in accordance with SOCATA SB TB aircraft 10-080-57 Revision 3.\n\nNote: DGAC AD 94-266(A)R3 refers.\n\nCompliance: For an attachment bearing that has:\n\n    reached or exceeded 6000 landings or 4000 hours time in service - at the next inspection for Maintenance Release issue, or within 100 hours time in service after 29 February 1996, whichever occurs first; thereafter at intervals not exceeding 1500 landings or 1000 hours time in service whichever occurs first; or\n\n    b. less than 5999 landings or 3999 hours time in service - prior to attaining 6000 landings or 4000 hours time in service, whichever occurs first; thereafter at intervals not exceeding 1500 landings or 1000 hours time in service whichever occurs first.\n\nThe compliance of the initial issue of this Directive remains unchanged. This Amendment becomes effective on 20 May 1999.\n\nBackground: This Directive was issued to ensure the integrity of the hinged strut attachment bearings.\n\nAmendment 1 is issued in response to a revision of the related DGAC AD which introduces Revision 3 of the Requirement Document.\n\nThe original issue of this Airworthiness Directive became effective on 29 February 1996.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment is purely technical — it updates the referenced service bulletin to Revision 3 without expanding the scope beyond the original landing gear bearing inspection requirement. The applicability (TB20/TB21 serial numbers 1-9999) and the fundamental safety purpose remain identical to the 1996 original."},"complexity_factors":["Multiple compliance pathways based on aircraft usage (landings vs. flight hours)","Nested time-based triggers (initial compliance vs. recurring intervals)","Cross-reference to external technical documents (SOCATA Service Bulletin TB aircraft 10-080-57 Revision 3, DGAC AD 94-266(A)R3)","Date-specific grandfathering (29 February 1996 effective date for original directive)","Dual metric system for tracking wear (landings AND hours — operator must track whichever threshold hits first)"],"plain_english_summary":"This directive requires owners/operators of Aerospatiale (Socata) TB20 and TB21 (serials 1–9999) and their maintenance engineers to inspect and maintain the main landing‑gear hinged‑strut attachment bearings because wear can lead to gear collapse.\n\nIt mandates proactive inspections and replacements tied to aircraft usage to prevent catastrophic failure. Amendment 1 merely updates the referenced SOCATA service bulletin to Revision 3 to align with the DGAC— the safety requirement itself is unchanged."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 1 updates the Requirement Document reference to SOCATA SB TB aircraft 10-080-57 Revision 3 and notes it responds to a DGAC AD revision, but explicitly states that \"The compliance of the initial issue of this Directive remains unchanged.\" The applicability, thresholds and recurring inspection intervals remain as originally set."},"complexity_factors":["Threshold-based compliance: different initial triggers depending on whether bearings have reached 6,000 landings/4,000 hours or not, then recurring intervals (1500 landings / 1000 hours).","Cross-reference to an external Requirement Document (SOCATA SB TB aircraft 10-080-57 Rev 3) for detailed work instructions.","Applicability limited by model and serial number range (TB20 and TB21 S/nos 1 to 9999).","Timing tied to Maintenance Release inspections and a specific compliance timeline (e.g. within 100 hours after 29 Feb 1996) creating schedule coordination obligations.","Amendment updates the reference document rather than changing the core compliance regime, so operators must track document revisions to remain compliant."],"plain_english_summary":"Mandates inspection of main landing‑gear hinged strut attachment bearings on Socata TB20/TB21 aeroplanes (serials 1–9999), to be carried out in accordance with SOCATA SB TB aircraft 10‑080‑57 Revision 3. Inspections are triggered at specified landing‑count or flight‑hour thresholds and then repeated at set intervals.\n\nApplies to owners/operators who must schedule and pay for inspections and any repairs; the stated purpose is to ensure bearing integrity. Amendment 1 updates the referenced service document while leaving the original compliance requirements unchanged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings","history":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings/history","analysis":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings/analysis","conflicts":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings/conflicts","importantCases":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings/important-cases","documents":"/api/acts/ad-tb20-32-amdt-1-mlg-hinged-strut-attachment-bearings/documents"}}