{"id":"F2008L00878","name":"AD/THIELERT/8 - Piston Cooling Nozzles","slug":"ad-thielert-8-piston-cooling-nozzles","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":72999,"registerId":"commonwealth-F2008L00878-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/8 | Piston Cooling Nozzles | 4/2008 |\n| ------------- | ---------------------- | ------ |\n\n| Applicability: | Thielert Aircraft Engines (TAE) TAE125-01 engines, except those engines that have been modified in accordance with TAE Design Modification No. 2007-001.Note 1: These engines are known to be installed on, but not limited to, Cessna 172 and (Reims-built) F172 series, Piper PA-28 series, APEX (Robin) DR 400 series, Diamond DA40 and DA42 aircraft.                                                                                       |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect the piston cooling nozzle in accordance with TAE TM TAE125-0017 dated 14 December 2007 or later approved revision.2. Repeat the inspection detailed in Requirement 1 of this AD.3. When a broken piston cooling nozzle is found during any inspection as detailed in Requirement 1 or 2 of this AD, contact TAE, do not operate the engine anymore and send it back to TAE.Note 2: EASA AD 2008-016R1 dated 22 February 2008 refers. |\n| Compliance:    | 1. Within the next 110 Flight Hours (FH) or 6 months or during the next scheduled maintenance, whichever occurs first after the effective date of this AD.2. Thereafter, at intervals not to exceed 100 flight hours (FH) (+/- 10 FH).3. Before further flight after the effective date of this AD.                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 10 April 2008.                                                                                                                                                                                                                                                                                                                                                                                |\n\n| Background: | In-flight engine shutdown incidents were reported on aircraft equipped withTAE125-01 engines. This was found to be mainly the result of operation over a long time period with broken piston cooling oil nozzles which caused thermal overload of the piston. Consequently, the German Federal Bureau for the investigation of transportation accidents (BFU) issued Safety Recommendation no. 10/2007. For the reasons stated above, this Airworthiness Directive (AD) requires the inspection of all affected TAE125-01. This AD excludes those engines that have been modified in accordance with TAE Design Modification No. 2007-001. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n27 February 2008","sortOrder":0},{"sectionNumber":"AD/THIELERT/8","sectionType":"part","heading":"AD/THIELERT/8","content":"## AD/THIELERT/8","sortOrder":1},{"sectionNumber":"Piston Cooling Nozzles","sectionType":"part","heading":"Piston Cooling Nozzles","content":"## Piston Cooling Nozzles","sortOrder":2},{"sectionNumber":"4/2008","sectionType":"part","heading":"4/2008","content":"## 4/2008","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 instrument's scope matches its stated purpose: require inspection of affected TAE125-01 engines while excluding engines modified by TAE Design Modification No. 2007-001. It does not broaden or narrow the population beyond that explicit carve-out."},"complexity_factors":["Technical dependency on Thielert maintenance document TAE TM TAE125-0017 for inspection procedure","Multiple compliance timing options (110 flight hours or 6 months or next scheduled maintenance) for initial inspection","Recurring inspection interval with a tolerance (100 FH ±10 FH)","Immediate operational prohibition and mandatory return-to-manufacturer if a broken nozzle is found","Applicability carve-out for engines modified by TAE Design Modification No. 2007-001","Cross-reference to external EASA AD 2008-016R1","Operational and logistical impacts on diverse aircraft types fitted with TAE125-01 engines"],"plain_english_summary":"This Airworthiness Directive requires operators of Thielert TAE125-01 engines (except those modified by TAE Design Modification No. 2007-001) to inspect piston cooling oil nozzles using the Thielert technical manual, to repeat inspections at regular intervals, and to stop flying and return any engine found with a broken nozzle to Thielert. It responds to reported in-flight shutdowns linked to piston thermal overload and places inspection, downtime and repair costs on operators, with specified initial and recurring compliance timeframes."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope: addressing a specific mechanical failure mode (broken piston cooling nozzles) in a specific engine model. The exclusion for modified engines (TAE Design Modification No. 2007-001) was part of the original design, not scope creep."},"complexity_factors":["Single, specific mechanical defect addressed (broken piston cooling nozzles)","Only 3 requirements with clear sequential numbering","Simple applicability test: TAE125-01 engines minus one specific modification","Straightforward compliance timeline with three alternative triggers (flight hours, calendar time, or maintenance event)","Minimal cross-referencing (one EASA AD mentioned in a note, not incorporated by complex reference)","No nested definitions or interpretation sections","Clear, imperative language ('inspect', 'repeat', 'do not operate')"],"plain_english_summary":"This mandatory CASA Airworthiness Directive targets Thielert TAE125-01 engines fitted to light aircraft (e.g., Cessna 172, Piper PA‑28, Diamond DA40/DA42) after reports of piston cooling nozzles breaking and causing piston overheating and in‑flight engine shutdowns. \n\nOwners/operators of affected engines (unless modified by TAE Design Mod. 2007‑001) must inspect the cooling nozzles promptly and periodically, ground aircraft if breaks are found, and return engines to TAE. It became mandatory on 10 April 2008."}},"importantCases":[],"_links":{"self":"/api/acts/ad-thielert-8-piston-cooling-nozzles","history":"/api/acts/ad-thielert-8-piston-cooling-nozzles/history","analysis":"/api/acts/ad-thielert-8-piston-cooling-nozzles/analysis","conflicts":"/api/acts/ad-thielert-8-piston-cooling-nozzles/conflicts","importantCases":"/api/acts/ad-thielert-8-piston-cooling-nozzles/important-cases","documents":"/api/acts/ad-thielert-8-piston-cooling-nozzles/documents"}}