{"id":"F2008L02078","name":"AD/THIELERT/9 Amdt 1 - Engine - Clutch Assembly","slug":"ad-thielert-9-amdt-1-engine-clutch-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74295,"registerId":"commonwealth-F2008L02078-current","compilationNumber":null,"startDate":"2026-04-02","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/9 Amdt 1 | Engine - Clutch Assembly | 8/2008 TX |\n| -------------------- | ------------------------ | --------- |\n\n| Applicability: | All Thielert Aircraft Engines GmbH TAE125-02-99 (commercial designation Centurion 2.0) engines having clutch assembly P/N 05-7211-K000304 installed.Note 1: These engines are known to be installed on, but not limited to, Cessna 172 and (Reims-built) F172 series (EASA STC Nr. EASA.A.S.01527), Piper PA-28 series (EASA STC Nr. EASA.A.S.01632), APEX (Robin) DR 400 series (EASA STC Nr. EASA.A.S.01380) and Diamond DA40 and DA42 aircraft.                                                                                                                                                                                           |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Replace the clutch in accordance with Thielert Aircraft Engines Service Bulletin TM TAE 125-1006 P1, Revision 1 or later NAA approved revision.Note 2: EASA Emergency AD 2008-0106-E dated 30 May 2008 refers. This AD supersedes EASA AD 2008-0100-E.                                                                                                                                                                                                                                                                                                                                                                                       |\n| Compliance:    | For engines that have accumulated, on the effective date of this AD, less than 50 Flight Hours (FH) since the last clutch inspection - Before the accumulation of 50 FH since last clutch inspection.For engines that have accumulated, on the effective date of this AD, between 50 FH and 300 FH since the last clutch inspection - Before further flight.Ferry FlightFor the purpose of this AD, one Ferry Flight with pilot only to a Maintenance Station is allowed, for engines that have accumulated more than 50 FH, to accomplish the engine clutch replacement required by this AD. The flight shall be limited to VFR conditions. |\n|                | This Amendment becomes effective on 16 June 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| Background:    | In-flight engine shutdown incidents have been reported on aircraft equipped with TAE125-02-99 engines. Preliminary investigations showed that it was mainly the result of cracked disc springs in the clutch. This condition, if not corrected, could result in further cases of engine in-flight shutdown and the consequent loss of control of the aircraft.                                                                                                                                                                                                                                                                               |\n\n|     | To address this unsafe condition, the original issue of this AD was published to mandate repetitive inspections until a new clutch P/N 05-7211-K006001 is installed.Since that publication, data collected from the performed inspections revealed that the sole clutch assembly P/N 05-7211-K000304 was subject to failure. For those reasons this amendment supersedes the previous requirements and requires the removal of the affected clutch assemblies P/N 05-7211-K000304 on all TAE125-02-99 engines and their replacement by new clutches of an improved design.The original issue of this AD became effective on 30 May 2008. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n11 June 2008","sortOrder":0},{"sectionNumber":"AD/THIELERT/9 Amdt 1","sectionType":"part","heading":"AD/THIELERT/9 Amdt 1","content":"## AD/THIELERT/9 Amdt 1","sortOrder":1},{"sectionNumber":"Engine - Clutch Assembly","sectionType":"part","heading":"Engine - Clutch Assembly","content":"## Engine - Clutch Assembly","sortOrder":2},{"sectionNumber":"8/2008 TX","sectionType":"part","heading":"8/2008 TX","content":"## 8/2008 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Yes. The amendment moves from the original AD's repetitive inspections to a mandatory removal and replacement of clutch assembly P/N 05‑7211‑K000304 with the improved P/N 05‑7211‑K006001, expanding intervention from monitoring to required part replacement (see \"To address this unsafe condition\" and \"This amendment supersedes\")."},"complexity_factors":["Safety‑critical mandatory replacement (not optional inspection) increases operational disruption and grounding risk.","Conditional compliance windows tied to flight hours since last inspection (<50 FH vs 50–300 FH) create scheduling complexity.","Cross‑references to external documents: Thielert Service Bulletin TM TAE 125‑1006 P1 Rev 1 (or later NAA‑approved revision) and EASA Emergency ADs.","Ferry flight exception limited to pilot‑only VFR imposes operational constraints and risk management requirements.","Supersedes prior AD that required repetitive inspections; scope change requires owners to move from monitoring to full part replacement.","Multiple aircraft types affected via STCs (Cessna, Piper, Diamond, Robin/APEX), increasing coordination across operators and maintenance organisations.","Enforcement by regulator (CASA) creates potential for variable national implementation and approval processes for later revisions."],"plain_english_summary":"This airworthiness directive requires owners/operators of Thielert TAE125‑02‑99 (Centurion 2.0) engines fitted with clutch assembly P/N 05‑7211‑K000304 to replace that clutch with an improved part (P/N 05‑7211‑K006001) pursuant to Thielert service instructions, after reports that cracked clutch disc springs caused in‑flight engine shutdowns. Aircraft owners/operators pay for and arrange replacements; the Civil Aviation Safety Authority enforces the AD. Affected engines must be taken out of service until replaced, although one limited pilot‑only VFR ferry flight is allowed to reach maintenance."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original directive (AD/THIELERT/9) required repetitive inspections of the clutch assembly. This Amendment 1 significantly narrows the scope by eliminating the inspection regime entirely and mandating outright replacement of the specific faulty part number. The scope shifted from ongoing monitoring to immediate corrective action based on new failure data."},"complexity_factors":["Short, single-purpose document (approximately 400 words)","Only 1 defined term ('Ferry Flight')","Simple conditional structure with 3 clear compliance pathways based on flight hours accumulated","Minimal cross-referencing (references one service bulletin and one superseded EASA directive)","Single technical requirement (clutch replacement) with one explicit exception (ferry flight provision)","No nested exceptions or recursive definitions"],"plain_english_summary":"This AD mandates replacement of the clutch assembly (P/N 05-7211-K000304) in Thielert TAE125-02-99 (Centurion 2.0) engines used on various light aircraft (Cessna, Piper, Robin, Diamond), after disc-spring cracking caused in-flight engine shutdowns. \n\nInspections proved insufficient, so affected engines must have the faulty clutch replaced; a single ferry flight (VFR, pilot only) is allowed to reach maintenance."},"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-thielert-9-amdt-1-engine-clutch-assembly","history":"/api/acts/ad-thielert-9-amdt-1-engine-clutch-assembly/history","analysis":"/api/acts/ad-thielert-9-amdt-1-engine-clutch-assembly/analysis","conflicts":"/api/acts/ad-thielert-9-amdt-1-engine-clutch-assembly/conflicts","importantCases":"/api/acts/ad-thielert-9-amdt-1-engine-clutch-assembly/important-cases","documents":"/api/acts/ad-thielert-9-amdt-1-engine-clutch-assembly/documents"}}