{"id":"F2009L00221","name":"AD/THIELERT/12 - Rail Pressure Control Valve","slug":"ad-thielert-12-rail-pressure-control-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76692,"registerId":"commonwealth-F2009L00221-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/12 | Rail Pressure Control Valve | 2/2009 |\n| -------------- | --------------------------- | ------ |\n\n| Applicability: | Thielert Aircraft Engines GmbH (TAE) 125-02-99 (commercial designation Centurion 2.0) engines.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 DA 40 D, DA 42 and DA 42 M aircraft.                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Replace the rail pressure control valve P/N 05-3940-K001501 and modify the VRail Plug in accordance with TAE SB TM 125-1008 P1 R1.2. Amend the approved engine maintenance schedule to incorporate the instructions of Chapter 5 “Airworthiness Limitations” of OM-02-02 Issue 1 Revision 2.3. Thereafter, accomplish the tasks within the thresholds and intervals (as) defined and instructed in Chapter 5 “Airworthiness Limitations” of OM-02-02 Issue 1 Revision 2.Engines with Serial Numbers (S/N) as identified in TAE SB TM 125-1008 P1 R1 have already incorporated these modifications and therefore do not need to comply with Requirement 1 of this AD.The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.Note 2: EASA AD 2008-0215 dated 5 December 2008 refers. |\n| Compliance:    | For Requirement 1 - Within the next 110 flight hours after the effective date of this AD, unless previously accomplished.For Requirement 2 - Within the next 3 months after the effective date of this AD, unless previously accomplished.For Requirement 3 - After the completion of Requirements 1 and 2 of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 12 February 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n\n| Background: | As a consequence of occurrences and service experience, Thielert Aircraft Engines GmbH has introduced a new rail pressure control valve Part Number (P/N)05-7320-E000702 and has amended the Airworthiness Limitation Section (ALS) of the Operation & Maintenance Manual OM-02-02 to include a replacement of the rail pressure control valve. Failure of this part could result in in-flight shut down(s) of the engine(s).This AD requires replacement of the rail pressure control valve, modification of the VRail Plug and the implementation of the instructions, limitations, inspections and corrective measures, as specified in TAE SB TM 125-1008 P1 and in issue 1 revision 2 of the chapter 5 of the OM-02-02. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n22 December 2008","sortOrder":0},{"sectionNumber":"AD/THIELERT/12","sectionType":"part","heading":"AD/THIELERT/12","content":"## AD/THIELERT/12","sortOrder":1},{"sectionNumber":"Rail Pressure Control Valve","sectionType":"part","heading":"Rail Pressure Control Valve","content":"## Rail Pressure Control Valve","sortOrder":2},{"sectionNumber":"2/2009","sectionType":"part","heading":"2/2009","content":"## 2/2009","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 directive remains focused on a safety corrective action: replacing a specific engine component and instituting mandated maintenance limitations to address the risk of in-flight engine shutdown. It does not expand beyond that safety purpose or add unrelated regulatory obligations; it aligns with the manufacturer's corrective measures as described in the Background and referenced service documents."},"complexity_factors":["Single-piece safety directive with three clear requirements (replacement/modification, maintenance schedule amendment, ongoing tasks).","References to external documents: TAE SB TM 125-1008 P1 R1.2 and OM-02-02 Issue 1 Revision 2.3 (cross-references increase implementation detail but not the AD's internal complexity).","Conditional exemption for engines with serial numbers already modified (one nested exception).","Multiple compliance timeframes: 110 flight hours, 3 months, and subsequent ongoing intervals (adds scheduling complexity).","Allowance for later approved revisions of referenced documents (introduces version-control discretion).","Cross-reference to an EASA AD (2008-0215) indicating harmonisation with overseas regulator guidance."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires replacement of the rail pressure control valve (old P/N 05-3940-K001501) with the new valve and a modification of the VRail Plug, following Thielert Service Bulletin TAE SB TM 125-1008 P1 R1.2. (This is Requirement 1.)\n- Requires amendment of the engine's approved maintenance schedule to include the tasks, limitations and intervals listed in Chapter 5 “Airworthiness Limitations” of the Operation & Maintenance Manual OM-02-02 Issue 1 Revision 2.3, and thereafter to carry out those tasks at the specified thresholds and intervals. (This is part of Requirement 1 and the ongoing Requirements.)\n- Makes the use of later approved revisions of the cited documents acceptable for compliance.\n- Exempts engines whose serial numbers are already identified in the service bulletin as having incorporated these modifications from Requirement 1.\n\n**Who is affected**\n\n- Owners and operators of Thielert Aircraft Engines GmbH TAE 125-02-99 (commercially Centurion 2.0) engines. These engines are commonly installed in aircraft such as Cessna 172/F172, Piper PA-28, Robin (APEX) DR 400, and Diamond DA 40/DA 42 series (as noted in the applicability section). \n\n**Why it matters (official reason and technical risk)**\n\n- The manufacturer introduced a new rail pressure control valve because service experience showed the old valve can fail. The background to the directive states that failure of the valve could cause in-flight engine shutdown(s). The AD therefore requires replacement and ongoing maintenance limitations/inspections to reduce the risk of in-flight shutdowns.\n\n**Deadlines and timing**\n\n- Valve replacement and VRail Plug modification (Requirement 1): within the next 110 flight hours after the effective date of the AD unless already done.\n- Other specified actions (Requirement 2): within 3 months after the effective date unless already done.\n- Some tasks are to be carried out after completing Requirements 1 and 2 as indicated in the manual (Requirement 3).\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Who pays: aircraft/engine owners or operators pay for the replacement part, the VRail Plug modification, and any labour and downtime required to carry out the work (these are private maintenance costs incurred by the operator). (See Requirement 1 and Background.)\n- Who decides: the Civil Aviation Safety Authority (CASA), via this Airworthiness Directive, mandates the work and enforces compliance; the detailed technical steps are implemented by the operator and their maintenance provider using the referenced Thielert service bulletin and manual. (See Requirement and Background references.)\n- Behaviour changes required: operators must modify the approved maintenance schedule to include the new Airworthiness Limitations (Chapter 5 of OM-02-02) and then perform the specified inspections, replacements and corrective actions at the intervals the manual prescribes. Operators must also install the new valve and plug modification within the stated time limit unless their engine is already modified.\n\n**Implementation, costs and trade-offs to consider**\n\n- Direct costs: purchase of the new valve, modification labour, and aircraft downtime while maintenance is carried out. The AD does not publish unit costs; those are borne by owners/operators.\n- Ongoing costs: adding mandatory Airworthiness Limitation tasks to the maintenance schedule will increase recurrent maintenance workload and cost over the life of the engine.\n- Operational impact: scheduling work within the 110 flight hour window or 3-month deadline may cause short-term disruption to flight operations; operators must plan for potential part lead times.\n- Compliance risk and verification: compliance depends on accurate amendment of maintenance records and execution of the OM-02-02 Chapter 5 items; regulatory oversight enforces completion.\n- Benefit allocation: the safety benefit (reduced risk of engine shutdown) accrues to crew, passengers and third parties, while the immediate financial burden falls on the owners/operators required to carry out the work.\n- Flexibility: the AD accepts later approved revisions of the cited documents for compliance, which reduces friction if the manufacturer issues updated instructions.\n\n**Summary statement**\n\n- This AD mandates a specific hardware replacement and a change to the engines' maintenance regime to address a risk of in-flight engine shutdown caused by the rail pressure control valve. Operators must install the new valve and plug modification within prescribed timeframes and adopt the Airworthiness Limitation tasks from the manufacturer's manual on an ongoing basis. The required actions impose direct and ongoing maintenance costs on owners/operators while aiming to reduce the operational safety risk identified by the manufacturer and regulator. (See Requirements and Background.)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific known defect in a specific engine model. The requirements remain tightly focused on the rail pressure control valve failure mode described in the background."},"complexity_factors":["Multiple cross-references to external technical documents (TAE SB TM 125-1008 P1 R1, OM-02-02 Issue 1 Revision 2)","Three distinct compliance requirements with different deadlines and dependencies (Requirement 3 only applies after 1 and 2 are complete)","Serial number exemption clause (some engines already modified don't need Requirement 1)","Acceptance of 'later approved revisions' creates a dynamic compliance standard","Technical aviation terminology requiring specialized knowledge (STC, P/N, ALS, VRail Plug)"],"plain_english_summary":"This Airworthiness Directive requires operators of Thielert Centurion 2.0 diesel engines (commonly in Cessna 172, Piper PA‑28, Diamond DA40/DA42, Robin DR400) to replace the rail pressure control valve with an improved unit, modify the VRail Plug, and update maintenance records to include new mandatory inspections. It prevents in‑flight engine shutdowns by mandating the hardware upgrade within 110 flight hours and the paperwork change within 3 months."}},"importantCases":[],"_links":{"self":"/api/acts/ad-thielert-12-rail-pressure-control-valve","history":"/api/acts/ad-thielert-12-rail-pressure-control-valve/history","analysis":"/api/acts/ad-thielert-12-rail-pressure-control-valve/analysis","conflicts":"/api/acts/ad-thielert-12-rail-pressure-control-valve/conflicts","importantCases":"/api/acts/ad-thielert-12-rail-pressure-control-valve/important-cases","documents":"/api/acts/ad-thielert-12-rail-pressure-control-valve/documents"}}