{"id":"F2007L01592","name":"AD/MAKILA/7 Amdt 1 - Digital Engine Control Unit Software","slug":"ad-makila-7-amdt-1-digital-engine-control-unit-software","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":66151,"registerId":"commonwealth-F2007L01592-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Turbomeca Turbine Engines - Makila Serie","sectionType":"division","heading":"Turbomeca Turbine Engines - Makila Series","content":"### Turbomeca Turbine Engines - Makila Series\n\n| AD/MAKILA/7 Amdt 1 | Digital Engine Control Unit Software | 7/2007 |\n| ------------------ | ------------------------------------ | ------ |\n\n| Applicability: | Makila 1A2 turboshaft engines. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | Note 1: These engines are known to be installed on, but not limited to, Super Puma Mark II helicopters. |\n| Requirement: | 1. If not previously accomplished in accordance with the original issue of this Directive, replace the digital engine control unit (DECU) with a DECU incorporating Modification TU 244C (upgrade of software version 9 to version 11) in accordance with Turbomeca Mandatory Service Bulletin No A298 73 0244 Update 1 dated 30 March 2007 update. |\n| | 2. Engines, post Modification TU 244C, may only be installed on a helicopter if the other engine is either post Modification TU 244C or TU 230C (previous version of the control system software). |\n| | Note 2: EASA AD 2007-0143 refers. |\n| Compliance: | For Requirement 1 - No later than 30 November 2008. |\n| | For Requirement 2 - As of the effective date of this Amendment. |\n| | This Amendment becomes effective on 5 July 2007. |\n| Background: | The French Direction Générale de l’Aviation Civile (DGAC) advised that a backup law at 65% of NG (gas generator speed) has been added to the control system of Makila 1A2 engines in order to limit the acceleration of the free turbine overspeed in the event of a failure of the drive train between the engine and the main gearbox.Tests performed on the engine test bench have revealed a possible scenario that can lead to the activation of another backup law at 85% of NG. In this scenario, there is no longer an overspeed protection by going into backup at 65% of NG therefore, in the event of a transmission interruption between the engine and the main gearbox, the free turbine can accelerate until it bursts. Incorporation of modification TU 244C on the control system software enables the overspeed protection function to be maintained, including in the occurrence scenario described above. |\n\n| | The original issue of this Directive required the use of the new version of the software, as introduced by modification TU 244C, to re-establish an acceptable level of overspeed protection. Additionally, the Directive ensured the compatibility of the two engines installed on the same helicopter. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment is issued following the revision of DGAC AD F-2006-029 by the European Aviation Safety Agency (EASA). The Amendment continues the requirement to upgrade the software, but references an updated Turbomeca service bulletin. The Amendment also continues the requirement to ensure installed engine compatibility. |\n| | The original issue of this Directive became effective on 13 April 2006. |\n\n![](image.001.png) \nCharles Lenarcic \nDelegate of the Civil Aviation Safety Authority\n\n25 May 2007","sortOrder":0},{"sectionNumber":"AD/MAKILA/7 Amdt 1","sectionType":"part","heading":"AD/MAKILA/7 Amdt 1","content":"## AD/MAKILA/7 Amdt 1","sortOrder":1},{"sectionNumber":"Digital Engine Control Unit Software","sectionType":"part","heading":"Digital Engine Control Unit Software","content":"## Digital Engine Control Unit Software","sortOrder":2},{"sectionNumber":"7/2007","sectionType":"part","heading":"7/2007","content":"## 7/2007","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Amendment does not materially change the original Directive's scope: it continues the original requirement to upgrade DECU software to re-establish overspeed protection and to ensure engine compatibility on the same helicopter (Background). The Amendment updates the referenced Turbomeca service bulletin and follows EASA's revision of the DGAC AD, and sets the Amendment effective date (Amendment text; Requirement 1; Note 2; Compliance)."},"complexity_factors":["Technical specificity: mandates a precise software change (`TU 244C`) rather than a general repair (Requirement 1).","Operational compatibility constraint: restricts pairing of engines on the same helicopter (Requirement 2), creating an equipment-matching burden for operators.","Compliance deadline and effective date: a fixed retrofit deadline (30 Nov 2008) and immediate applicability for compatibility rule (Compliance).","Dependence on external documents: requires following Turbomeca Mandatory Service Bulletin No A298 73 0244 Update 1 and cross-references EASA/DGAC ADs (Requirement 1; Note 2; Background).","Safety-critical consequence: action responds to a specific overspeed failure mode that can cause turbine burst (Background), increasing regulatory urgency and inspection/installation scrutiny.","Limited applicability: applies only to Makila 1A2 engines, narrowing legal exposure but concentrating operational impact on operators of affected aircraft (Applicability; Note 1)."],"plain_english_summary":"Requires Makila 1A2 engines to have their digital engine control unit (`DECU`) software upgraded from version 9 to version 11 (Modification `TU 244C`) by 30 November 2008, and prevents fitting a post-`TU 244C` engine with an incompatible older engine unless the other engine is post-`TU 244C` or `TU 230C`. The upgrade preserves overspeed protection to stop free-turbine overspeed and potential turbine burst, based on Turbomeca and aviation authority test findings."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Amendment maintains the original scope of the 2006 Directive. It continues the same software upgrade requirement and engine pairing rule, merely updating the reference to a revised service bulletin (Update 1 dated March 2007). The safety objective — preventing free turbine overspeed failure — remains unchanged from the original issue."},"complexity_factors":["Single, clearly defined applicability (one specific engine model)","Two straightforward requirements with explicit deadlines","Minimal defined terms (only technical abbreviations like DECU, NG, TU 244C)","No nested conditional logic or cross-references to other legislation","Single background scenario explaining the safety risk","Total length is approximately 400 words","Clear compliance dates with no exceptions or alternative methods of compliance described"],"plain_english_summary":"This CASA Airworthiness Directive mandates replacing the DECU software in Makila 1A2 turboshaft engines with software version 11 (TU 244C) because the older software can fail to engage a critical backup law after certain drive-train failures, risking a free-turbine burst and catastrophic engine loss.\n\nAll affected engines must be upgraded by 30 Nov 2008; from 5 Jul 2007 you may not mix an upgraded engine with an unmodified one. It affects operators of Super Puma Mark II helicopters and other users of Makila 1A2 engines."}},"importantCases":[],"_links":{"self":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software","history":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software/history","analysis":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software/analysis","conflicts":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software/conflicts","importantCases":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software/important-cases","documents":"/api/acts/ad-makila-7-amdt-1-digital-engine-control-unit-software/documents"}}