{"id":"F2006L01680","name":"AD/MAKILA/8 - Engine & Fuel Control - Engine Control Unit","slug":"ad-makila-8-engine-fuel-control-engine-control-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":59424,"registerId":"commonwealth-F2006L01680-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/8 | Engine & Fuel Control - Engine Control Unit | 7/2006 |\n| ----------- | ------------------------------------------- | ------ |\n\n| Applicability: | Makila 1A and 1A1 turbo-shaft engines post modifications TU190, TU202 or TU219, which are installed on AS 332 helicopters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Incorporate modification TU 241 by replacing the Anticipator or Pitch/Gas Link LPG board of the Engine Control Unit (ECU) in accordance with Turbomeca Mandatory Service Bulletin no. 298 73 0241.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | Note: EASA AD 2006-0070 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Compliance:    | Before 31 January 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 6 July 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | The control system of Makila 1A and 1A1 engines post modifications TU190, TU202 or TU219 includes an electrical back-up mode at 85% N1 (gas generator speed) activated on the detection of certain occurrences affecting engine control.The activation of the back-up mode is irreversible and freezes the engine at 85% N1.An analysis of reported in service occurrences showed that the back-up mode can be activated by an electrostatic discharge or by a malfunction of the collective pitch signal. The two engines fitted on the same helicopter can therefore be frozen in this back-up position at 85% N1.This Directive requires the incorporation of modification TU241 on the LPG board of the Makila 1A and 1A1 ECU, which reduces the risk by changing the conditions in which the engines switch to, and are maintained, in the 85% NG back-up mode. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n24 May 2006","sortOrder":0},{"sectionNumber":"AD/MAKILA/8","sectionType":"part","heading":"AD/MAKILA/8","content":"## AD/MAKILA/8","sortOrder":1},{"sectionNumber":"Engine & Fuel Control - Engine Control U","sectionType":"part","heading":"Engine & Fuel Control - Engine Control Unit","content":"## Engine & Fuel Control - Engine Control Unit","sortOrder":2},{"sectionNumber":"7/2006","sectionType":"part","heading":"7/2006","content":"## 7/2006","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific safety defect in a specific engine type. The scope remains precisely limited to the identified safety issue and required remedy."},"complexity_factors":["Single, specific technical requirement with no conditional exceptions","Only 4 defined technical terms requiring external knowledge (TU190, TU202, TU219, TU241, N1/NG, LPG board, ECU)","No cross-references to other legislation — only a non-binding note referencing an EASA directive","Clear, single compliance date with no phased or alternative compliance options","Narrow applicability: one engine series, one helicopter type, specific prior modifications only","Total length: approximately 250 words of substantive content"],"plain_english_summary":"This CASA Airworthiness Directive mandates replacement of the LPG circuit board in the Engine Control Unit on AS332 (Super Puma) helicopters with Makila 1A/1A1 engines that have TU190, TU202, or TU219 mods. It fixes a fault where electrostatic discharge or a faulty pitch signal can lock both engines at 85% power, leaving pilots unable to change power.\n\nThe corrective mod TU241 must be done per Turbomeca MSB 298 73 0241 before 31 January 2007; AD effective 6 July 2006."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive remains within the original safety-focussed remit: it prescribes a targeted hardware modification to address an identified failure mode (unintended irreversible activation of an 85% N1 back-up) for a narrowly defined set of engines and installations. It does not expand the regulatory reach beyond that technical safety remedy."},"complexity_factors":["Single, narrow mandatory action (replace a specified ECU LPG/Anticipator or Pitch/Gas Link board with TU241)","Limited applicability criteria: Makila 1A and 1A1 engines post TU190, TU202 or TU219 installed on AS332 helicopters","Short compliance structure with fixed effective and compliance dates (6 July 2006; compliance by 31 January 2007)","Cross-reference to one manufacturer Mandatory Service Bulletin (Turbomeca MSB no. 298 73 0241) and one foreign AD (EASA AD 2006-0070)","Technical content delegated to the Service Bulletin (implementation detail not set out in the Directive itself)","No multi-layered exceptions or conditional sub-classes beyond the modification and installation qualifiers"],"plain_english_summary":"**What this directive does**\n\n- This Airworthiness Directive orders the modification of the Engine Control Unit (ECU) on certain Turbomeca Makila 1A and 1A1 turboshaft engines. Operators must replace a specific circuit board in the ECU (the Anticipator or Pitch/Gas Link LPG board) with the design introduced by modification TU241, following Turbomeca Mandatory Service Bulletin no. 298 73 0241. (Requirement)\n\n**Which engines and aircraft are covered**\n\n- Only Makila 1A and 1A1 engines that have already had modifications TU190, TU202 or TU219 and that are installed on AS332 helicopters are within scope. (Applicability)\n\n**When the work must be done**\n\n- The modification had to be completed by 31 January 2007. The Directive took effect on 6 July 2006. (Compliance)\n\n**Why the change was required (mechanics and safety risk)**\n\n- The Makila engines fitted as described include an electrical back-up mode that automatically activates at about 85% N1 (gas generator speed) when certain faults occur. When that back-up mode is triggered it is irreversible and holds the engine at 85% N1 (Background).\n- In service reports showed the back-up mode can be triggered unintentionally by an electrostatic discharge or by a malfunction of the helicopter collective pitch signal; both engines on one helicopter can therefore be frozen at the 85% N1 back-up state, which is a safety risk. (Background)\n- Modification TU241 changes the conditions under which the ECU switches to, and stays in, the 85% N1 back-up mode, thereby reducing the chance of unintended irreversible activation. (Requirement; Background)\n\n**Who pays and who decides**\n\n- The legal requirement is issued by the aviation authority (the Directive). The technical steps are specified by the engine manufacturer through its Mandatory Service Bulletin. Aircraft operators or owners must arrange and fund the board replacement and any associated downtime, parts, and labour. (Requirement; Compliance)\n\n**Practical effects and implementation notes**\n\n- Operators must schedule the ECU board replacement in maintenance programs and ensure no affected helicopter continues to fly beyond the compliance date without the modification. (Compliance)\n- The work requires sourcing the correct replacement LPG/Anticipator or Pitch/Gas Link board and competent maintenance personnel to fit it in accordance with Turbomeca's instructions. (Requirement)\n- Implementation risks include parts availability, maintenance scheduling and associated aircraft downtime, and potential installation errors if not done per the Service Bulletin. These are ordinary costs of a mandatory safety modification. (Requirement; Background)\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: the operator bears parts, labour and downtime costs. (Requirement)\n- Concentrated benefits: the safety benefit accrues to individual helicopter operators, crews and passengers (reduced risk of both engines freezing at 85% N1). The manufacturer benefits from addressing an identified failure mode via its modification. (Background)\n- Diffuse costs: if many operators must schedule the same work in a short period, there may be temporary pressure on parts supply and maintenance resources. (Compliance)\n- Behavioural effects: operators will incorporate the modification into scheduled maintenance; some may defer use of an affected helicopter until modification is fitted (operational downtime). The Directive does not remove or restrict other pilot or operator choices beyond requiring the hardware change for continued lawful operation. (Compliance; Requirement)\n\n**Cross-references and source documents**\n\n- The Directive refers operators to Turbomeca Mandatory Service Bulletin no. 298 73 0241 for the detailed steps. It also notes a related EASA AD (2006-0070) as a reference. (Requirement; Note)\n\nOverall, the instrument mandates a specific hardware change to the ECU on a narrowly defined group of Makila engines to reduce the risk of inadvertent, irreversible activation of an 85% N1 back-up mode. (Applicability; Requirement; Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit","history":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit/history","analysis":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit/analysis","conflicts":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit/conflicts","importantCases":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit/important-cases","documents":"/api/acts/ad-makila-8-engine-fuel-control-engine-control-unit/documents"}}