{"id":"F2005L01709","name":"AD/THIELERT/5 - Clutch Friction Plates","slug":"ad-thielert-5-clutch-friction-plates","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":35778,"registerId":"commonwealth-F2005L01709-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Thielert Piston Engines","sectionType":"division","heading":"Thielert Piston Engines","content":"### Thielert Piston Engines\n\n| AD/THIELERT/5 | Clutch Friction Plates | 8/2005 TX |\n| ------------- | ---------------------- | --------- |\n\n| Applicability: | All Thielert TAE 125-01 “a.m.” model Engines on which a clutch is installed, which has been delivered with a “Form One” number listed in Thielert Service Bulletin No. TM TAE 125-0011 Revision 3 of 13 June 2005.                                                                                                                                                          |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Exchange clutch assemblies per manufacturers repair manual RM -02-01 chapter 5orExchange the clutch friction plate per manufacturers repair manual RM -02-01 chapter 56.Note: LBA Airworthiness Directive AD-2005-229 issued in accordance with Article 10.1 of European Union Regulation 1592/2002 refers.                                                                 |\n| Compliance:    | Before the next flight after the effective date of this AD.                                                                                                                                                                                                                                                                                                                 |\n|                | This Airworthiness Directive becomes effective on 30 June 2005.                                                                                                                                                                                                                                                                                                             |\n| Background:    | A TAE 125 powered aircraft suffered a significant loss of power in flight. An investigation performed by the manufacturer revealed a failure of the clutch friction plate. The actions specified by this Airworthiness Directive are intended to prevent loss of power in flight which could result in reduced controllability of the aircraft and possible forced landing. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n24 June 2005","sortOrder":0},{"sectionNumber":"AD/THIELERT/5","sectionType":"part","heading":"AD/THIELERT/5","content":"## AD/THIELERT/5","sortOrder":1},{"sectionNumber":"Clutch Friction Plates","sectionType":"part","heading":"Clutch Friction Plates","content":"## Clutch Friction Plates","sortOrder":2},{"sectionNumber":"8/2005 TX","sectionType":"part","heading":"8/2005 TX","content":"## 8/2005 TX","sortOrder":3}],"analysis":{"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":"The AD is tightly focused on a specific failure mode (clutch friction plate failure) and prescribes immediate replacement for affected units. It does not expand beyond that safety purpose into broader maintenance, operational, or certification requirements. Therefore the scope has not grown beyond its original, safety‑remedial intent; it remains narrowly targeted to remove the defective component(s) identified by the manufacturer’s investigation."},"complexity_factors":["Short, single‑issue directive (replacing clutch friction plates)","One conditional applicability clause (applies only to engines with specific Form One numbers listed in a Service Bulletin)","Two alternative remedial actions referenced (replace clutch assembly OR replace friction plate)","Cross‑references to two external documents: Thielert Service Bulletin TM TAE 125-0011 Rev 3 and manufacturer repair manual RM‑02‑01 (chapters 5 and 56)","Urgent compliance timing (must be done before the next flight)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive that applies to Thielert TAE 125-01 “a.m.” piston engines that have a clutch fitted and that were delivered with the specific “Form One” numbers listed in Thielert Service Bulletin TM TAE 125-0011 Revision 3 (13 June 2005).\n- It requires operators to either:\n  - exchange the entire clutch assembly in accordance with the manufacturer’s repair manual (RM‑02‑01 chapter 5), or\n  - exchange just the clutch friction plate in accordance with the manufacturer’s repair manual (RM‑02‑01 chapter 56).\n- The replacement must be carried out before the next flight after the directive’s effective date. The AD became effective on 30 June 2005.\n\n**Who is affected**\n\n- Aircraft owners/operators using Thielert TAE 125‑01 engines with the specified Form One numbers and with a clutch installed.\n- Maintenance organisations and technicians who perform work under the manufacturer’s repair manual RM‑02‑01.\n- Parts suppliers (clutch assemblies and friction plates) because demand for those parts will be immediate.\n\n**Why it matters**\n\n- The directive responds to a reported in‑flight significant loss of power traced to failure of a clutch friction plate. The stated purpose is to prevent loss of engine power in flight, which could reduce controllability and lead to a forced landing.\n- Compliance is mandatory for affected aircraft and must be completed before the aircraft’s next flight, creating an immediate operational requirement.\n\n**Mechanics of implementation and cross‑references**\n\n- The AD does not mandate a new inspection regime; it mandates part replacement in line with the manufacturer’s repair manual procedures identified above.\n- It references Thielert Service Bulletin TM TAE 125-0011 Revision 3 for applicability (the list of Form One numbers) and notes a related LBA (German authority) AD (AD‑2005‑229) invoked under EU Regulation 1592/2002 — this is cited as related regulatory material, not as an alternative compliance route.\n\n**Costs, incentives and trade‑offs (practical effects)**\n\n- Who pays: aircraft owners/operators pay for parts and labour (clutch assembly or friction plate replacement) and for any associated downtime.\n- Who decides how to comply: maintenance providers and licensed technicians must carry out the replacement following the manufacturer’s repair manual; the operator decides scheduling and whether to replace the whole assembly or just the plate where both options are permitted.\n- Immediate costs: emergency scheduling, possible AOG (aircraft on ground) situations if parts are scarce, and direct parts and labour expense.\n- Benefit concentrated; cost widespread: maintenance suppliers and Thielert (or authorised resellers) may capture concentrated sales of parts and labour; many operators bear relatively small but immediate costs and operational disruption.\n- Compliance burden and implementation risk: the requirement to act before the next flight is strict and creates operational disruption risk if parts or qualified personnel are not immediately available.\n\n**Compliance and regulatory discretion**\n\n- The AD is prescriptive: it specifies which engines are affected and which repair‑manual procedures must be used. There is limited room for alternate methods of compliance unless an authority (e.g. CASA) approves an alternative means.\n\n**Notes on source claims**\n\n- The explanatory background states a manufacturer investigation found a clutch friction plate failure after an in‑flight power loss; the AD’s remedial measures are designed to address that failure mode by replacement. The AD also notes the related LBA AD as a coordinating reference under relevant EU rules."},"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 engine model. It has not expanded beyond its original purpose of mandating clutch friction plate replacement."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined term implicitly referenced (\"Form One\" — a standard aviation document certifying part conformity)","Single compliance pathway with two alternative actions (replace assembly OR plate)","No nested exceptions or conditional logic","Clear applicability criteria referencing external manufacturer bulletin","Simple temporal trigger (before next flight after effective date)"],"plain_english_summary":"This AD mandates that operators of Thielert TAE 125-01 \"a.m.\" engines fitted with the identified clutch must replace the faulty clutch assembly or the clutch friction plate per the manufacturer’s repair manual before the next flight after 30 June 2005. It responds to an in-flight clutch failure that caused loss of power and adopts findings from the German LBA AD to prevent similar emergency landings or crashes."}},"importantCases":[],"_links":{"self":"/api/acts/ad-thielert-5-clutch-friction-plates","history":"/api/acts/ad-thielert-5-clutch-friction-plates/history","analysis":"/api/acts/ad-thielert-5-clutch-friction-plates/analysis","conflicts":"/api/acts/ad-thielert-5-clutch-friction-plates/conflicts","importantCases":"/api/acts/ad-thielert-5-clutch-friction-plates/important-cases","documents":"/api/acts/ad-thielert-5-clutch-friction-plates/documents"}}