{"id":"F2006B06709","name":"AD/S-76/27 - Main Rotor Blade Spar Tip End - Inspection","slug":"ad-s-76-27-main-rotor-blade-spar-tip-end-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114522,"registerId":"commonwealth-F2006B06709-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/S-76/27 - Main Rotor Blade Spar Tip End - Inspection","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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Sikorsky S-76 Series Helicopters\n\n \n\nAD/S-76/27 Main Rotor Blade Spar Tip End - Inspection 5/83\n\nApplicability: All models with main rotor blade assemblies P/N 76150-09000 and P/N 76150- 09100-041 thru -050, unless the blade assemblies are marked as RS-004E-II or RS- 004F-II.\n\n \n\nDocument: Sikorsky Alert Service Bulletin No. 76-65-34.\n\n \n\nCompliance: Within 100 hours time in service after 31 May 1983 and thereafter at each scheduled tip cap removal.\n\n \n\nBackground:  Cracks were detected at the spar tip end in one blade undergoing repair at Sikorsky Aircraft.\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":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope is to require inspection of the spar tip end on specified Sikorsky S-76 blade assemblies after the discovery of a crack in one blade (Background). The text confines the requirement to particular part numbers and excludes blades with specific markings (Applicability), and sets definite timing for inspection (Compliance). There is no indication in the supplied text that the scope departs from that apparent intent."},"complexity_factors":["Clear and limited applicability defined by part numbers and two specific marking exceptions (Applicability).","Single, simple compliance timing: initial 100-hour window and recurrence at scheduled tip cap removal (Compliance).","Reliance on a single external procedural document (Sikorsky Alert Service Bulletin No. 76-65-34) for technical implementation (Document).","No multiple compliance paths, exemptions, or staged requirements in the text.","Limited factual background (single event) reduces interpretive complexity but leaves repair specifics to the referenced service bulletin (Background; Document)."],"plain_english_summary":"This directive requires owners/operators of Sikorsky S‑76 helicopters fitted with specified main rotor blade assemblies (listed P/Ns, except those marked RS‑004E‑II or RS‑004F‑II) to inspect the spar tip end using Sikorsky Alert Service Bulletin No. 76‑65‑34. The first inspection is due within 100 hours after 31 May 1983 and thereafter at each scheduled tip‑cap removal. It was issued after a spar‑tip crack was found and increases routine maintenance obligations and costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in a specific helicopter model. It has not expanded beyond its original purpose of mandating inspections for spar tip cracks in S-76 main rotor blades."},"complexity_factors":["Single, specific technical requirement (visual/physical inspection of one component)","Only 2 defined part number ranges in applicability, plus 2 exemption markings","Simple compliance timeline: 100 hours after fixed date, then recurring with maintenance","No nested exceptions or conditional logic — exemption is straightforward marking check","Short document (approximately 150 words of substantive content)","Single external reference to manufacturer service bulletin"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of certain **Sikorsky S-76 helicopters** to inspect the main rotor blades for cracks.\n\n**Who it affects:**\n- Operators of Sikorsky S-76 helicopters with specific blade part numbers (76150-09000 and 76150-09100-041 through -050)\n- Unless those blades are already marked with \"RS-004E-II\" or \"RS-004F-II\" (which means they've already been modified or inspected under a different standard)\n\n**What it requires:**\n- Inspect the **spar tip end** (the internal structural 'backbone' at the tip of the rotor blade) for cracks\n- First inspection must happen within **100 flight hours** after 31 May 1983\n- Repeat the inspection **every time the tip cap is removed** for scheduled maintenance\n\n**Why it matters:**\nCracks were found in a blade during repair work at the manufacturer. If undetected, these cracks could cause **catastrophic blade failure** — potentially leading to loss of the aircraft and lives. This AD forces operators to check for this specific defect before it becomes dangerous.\n\n**Key document reference:**\nOperators must follow the procedures in **Sikorsky Alert Service Bulletin No. 76-65-34** to perform the inspection correctly."}},"importantCases":[],"_links":{"self":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection","history":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection/history","analysis":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection/analysis","conflicts":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection/conflicts","importantCases":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection/important-cases","documents":"/api/acts/ad-s-76-27-main-rotor-blade-spar-tip-end-inspection/documents"}}