{"id":"F2006B07522","name":"AD/TURMO/4 - Fuel Control - Acceleration Unit","slug":"ad-turmo-4-fuel-control-acceleration-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50054,"registerId":"commonwealth-F2006B07522-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TURMO/4 - Fuel Control - Acceleration Unit","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Turbomeca Turbine Engines - Turmo Series\n\n \n\nAD/TURMO/4 Fuel Control - Acceleration Unit 10/92\n\nApplicability: All Turmo IV A, B, C, CA and CB engines.\n\n \n\nRequirement: Unless previously carried out, action in accordance with Turbomeca Service Bulletin No 088.\n\n \n\nNote: DGAC AD 92-115(B) refers.\n\n \n\nCompliance: Prior to 30 September 1992.\n\n \n\nBackground: In certain operating conditions the vibratory torsion modes between the gearbox and engine could damage both engine flexible couplings.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow, specific scope (particular engine models, single maintenance action). It has not expanded beyond its original purpose of addressing a specific vibration/coupling failure mode."},"complexity_factors":["Very short document — approximately 150 words of substantive content","Only 1 defined applicability criterion (specific engine models)","Single, unambiguous compliance requirement (follow Service Bulletin No. 088)","No cross-references to other legislation or complex conditional logic","Simple, fixed deadline with no exceptions or alternative compliance methods","No nested definitions or interpretive provisions"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific **Turbomeca Turmo IV series turbine engines** (models A, B, C, CA, and CB) to carry out a specific maintenance action. The action involves following instructions in **Turbomeca Service Bulletin No. 088** to address a problem with the **fuel control acceleration unit**.\n\n**Why it matters:** Under certain operating conditions, vibrations between the engine and gearbox can damage the engine's flexible couplings. This damage could lead to engine failure or other serious safety hazards in aircraft using these engines. The directive ensures this safety issue is fixed before a deadline.\n\n**Who must comply:** Anyone operating aircraft with these specific Turmo IV engines — including airlines, charter operators, private owners, and maintenance organisations.\n\n**Key deadline:** The required action had to be completed **before 30 September 1992**.\n\n**Note:** This references a French aviation safety directive (DGAC AD 92-115(B)), showing this was a coordinated international safety response."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD applies to the specified Turmo IV engine models and mandates the corrective action described in Turbomeca Service Bulletin No 088 to mitigate a vibration-related risk to flexible couplings. The instrument's operative scope (which engines are covered and the required remedial action and compliance date) is set out clearly in the text and aligns with the stated safety rationale (Background; Applicability; Requirement; Compliance). There is no indication in the text that the AD narrows or broadens that scope from any previously stated intent."},"complexity_factors":["Narrow technical scope: limited to Turbomeca Turmo IV A, B, C, CA and CB engines (Applicability).","Single mandatory remedy but reliance on an external technical document (Turbomeca Service Bulletin No 088) for substantive instructions (Requirement).","Hard compliance deadline creates scheduling/operational constraints (Compliance).","Limited regulatory text — technical details, costs and authorised performers are delegated to the Service Bulletin, increasing practical dependence on an external source (Requirement).","Cross-reference to a foreign authority directive (DGAC AD 92-115(B)) introduces an additional document to consult for context (Note)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Turbomeca Turmo IV A/B/C/CA/CB engines to carry out the corrective maintenance specified in Turbomeca Service Bulletin No. 088 by 30 September 1992. It addresses vibration‑induced torsional risk to flexible couplings; technical, procedural and cost details (how, who performs the work) are left to the Service Bulletin and the affected operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit","history":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit/history","analysis":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit/analysis","conflicts":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit/conflicts","importantCases":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit/important-cases","documents":"/api/acts/ad-turmo-4-fuel-control-acceleration-unit/documents"}}