{"id":"F2006B06728","name":"AD/S-76/52 - Power Turbine Speed Trim Control Actuators","slug":"ad-s-76-52-power-turbine-speed-trim-control-actuators","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114554,"registerId":"commonwealth-F2006B06728-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/S-76/52 - Power Turbine Speed Trim Control Actuators","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nSikorsky S-76 Series Helicopters\n\n| AD/S-76/52                 | Power Turbine Speed Trim Control Actuators                                                                                    | 7/88DM |\n| -------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | ------ |\n| Applicability:Requirement: | All model S-76A helicopters fitted with Allison Model 250-C30 engines.Action in accordance with Sikorsky Alert SB No 76-76-3. |        |\n\nCompliance: 1. Within 25 hours time in service or by 10 June 1988, whichever occurs first, inspect in accordance with para E2 of Requirement Document.\n\n2. At next inspection for issue of a Maintenance Release after 10 June 1988 or within 100 hours time in service after 10 June 1988, whichever occurs first, or if vertical movement in the power turbine control torque shaft is detected, inspect in accordance with Para E3 of Requirement Document.\n\nBackground: The manufacturer has advised that a power turbine speed trim actuator has disengaged from the power turbine control torque shaft causing a loss of engine power.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1615},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive issued in response to a specific defect identified by the manufacturer. The scope remains precisely limited to addressing the identified safety risk involving power turbine speed trim control actuators on the specified helicopter models."},"complexity_factors":["Single, specific mechanical issue addressed","Limited applicability (one helicopter model with specific engines)","Simple two-stage compliance schedule with clear deadlines","Cross-reference to only one manufacturer document","Minimal defined terms or conditional exceptions"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Sikorsky S‑76A helicopters with Allison Model 250‑C30 engines to inspect the power turbine speed trim control actuator for disengagement from the power turbine control torque shaft. A disengaged actuator can cause sudden engine power loss and possible crash. Initial inspection is due within 25 flight hours or by 10 June 1988 (whichever is first); follow Sikorsky Alert Service Bulletin No. 76‑76‑3 for procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators","history":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators/history","analysis":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators/analysis","conflicts":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators/conflicts","importantCases":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators/important-cases","documents":"/api/acts/ad-s-76-52-power-turbine-speed-trim-control-actuators/documents"}}