{"id":"F2006B06224","name":"AD/PHZL/66 - Blade Pitch Change Knob","slug":"ad-phzl-66-blade-pitch-change-knob","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47141,"registerId":"commonwealth-F2006B06224-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PHZL/66 - Blade Pitch Change Knob","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Propellers - Variable Pitch - Hartzell\n\n \n\nAD/PHZL/66 Blade Pitch Change Knob 9/94 DM\n\nApplicability: All model HC-E4A-3A/E10950( ) propellers prior to and including S/N HJ198 installed on Beech 1900D aircraft.\n\n \n\nRequirement: Unless previous carried out action in accordance with Hartzell Alert Service Bulletin A190.\n\n \n\nNote: FAA AD 94-10-01 Amdt 39-8908 refers.\n\n \n\nCompliance: As specified in the Requirement Document effective from 6 July 1994.\n\n \n\nBackground: The manufacturer has advised that failure of the pitch change knob attachment screws can cause vibration and failure of the propeller to completely go into the feather position.\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, targeted safety directive addressing a specific mechanical defect in specific propellers. It has not expanded beyond its original purpose of mandating a manufacturer-recommended safety fix."},"complexity_factors":["Single, specific applicability clause targeting one propeller model range","Single requirement referencing an external technical document (Hartzell Service Bulletin)","No defined terms section","No conditional logic or nested exceptions","Minimal cross-referencing (only one FAA AD reference in a note)","Extremely short document (under 200 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA).\n\n**What it does:**\nIt requires owners or operators of specific Hartzell propellers (model HC-E4A-3A/E10950 series, serial numbers up to HJ198) installed on Beech 1900D aircraft to carry out a safety inspection or repair.\n\n**The problem:**\nThe manufacturer discovered that screws attaching the \"pitch change knob\" (a component that adjusts the angle of the propeller blades) could fail. If these screws break, it can cause dangerous vibration and prevent the propeller from \"feathering\" properly — that's when blades turn edge-on to stop the aircraft engine from windmilling after shutdown or failure. This is critical for safety during flight and emergency situations.\n\n**What must be done:**\nOperators must follow the instructions in **Hartzell Alert Service Bulletin A190** — a technical notice from the manufacturer describing the required inspection or fix.\n\n**Who it affects:**\nAnyone operating Beech 1900D aircraft with these specific Hartzell propellers.\n\n**Why it matters:**\nPropeller failures can be catastrophic. This directive prevents accidents by catching a known mechanical defect before it causes in-flight emergencies."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive applies to a clearly defined set of propellers installed on Beech 1900D aircraft and requires the actions in Hartzell Alert Service Bulletin A190 unless already done (Applicability; Requirement). The text does not indicate any expansion or narrowing of that scope from an earlier instrument; it sets a single-scope requirement tied to serial numbers and the ASB, with compliance effective from 6 July 1994 (Applicability; Compliance)."},"complexity_factors":["Narrow, serial-number-limited applicability (specific propeller model and S/N up to HJ198) requiring serial-number checks (Applicability).","Direct reference and dependence on an external technical document (Hartzell Alert Service Bulletin A190) for the required work (Requirement).","Requirement is binary (either ASB action completed or must be completed) with a fixed compliance reference date (Compliance effective 6 July 1994).","Technical subject matter (propeller pitch-change mechanism) requires specialised maintenance skills and parts, increasing practical implementation complexity for operators though not for legal interpretation (Background; Requirement).","Cross-reference to FAA AD introduces an additional source to consult but does not change the mandatory action (Note)."],"plain_english_summary":"The directive requires owners/operators of Hartzell HC-E4A-3A/E10950 propellers (S/Ns up to HJ198) installed on Beech 1900D aircraft to carry out the corrective work in Hartzell Alert Service Bulletin A190 (if not already done). CASA makes this mandatory to address manufacturer‑reported pitch‑change knob screw failures that can cause vibration and prevent feathering. Operators bear the cost, schedule the work, and must record compliance; the action trades short‑term downtime for reduced in‑flight risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-phzl-66-blade-pitch-change-knob","history":"/api/acts/ad-phzl-66-blade-pitch-change-knob/history","analysis":"/api/acts/ad-phzl-66-blade-pitch-change-knob/analysis","conflicts":"/api/acts/ad-phzl-66-blade-pitch-change-knob/conflicts","importantCases":"/api/acts/ad-phzl-66-blade-pitch-change-knob/important-cases","documents":"/api/acts/ad-phzl-66-blade-pitch-change-knob/documents"}}