{"id":"F2006B06204","name":"AD/PHZL/24 - Propeller Attachment - Modification and Inspection","slug":"ad-phzl-24-propeller-attachment-modification-and-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47084,"registerId":"commonwealth-F2006B06204-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PHZL/24 - Propeller Attachment - Modification and Inspection","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPropellers \\- Variable Pitch \\- Hartzell\n\nAD/PHZL/24 Propeller Attachment \\- Modification and Inspection 4/69\n\nApplicability: All model HC-A3VF series propellers fitted to Continental GTS10-520 series engines.\n\nRequirement: 1. Replace propeller mounting bolts and washers with P/No.A-1328-1 bolts and P/No. A-1381 washers and torque to 80-85 pounds feet.\n\n    2. Check for loss of torque on the propeller mounting bolts by applying a measured torque of 80-85 pounds feet.\n\n    3. In the event of any substantial loss of torque of the mounting bolts being found, or of excessive rough running being experienced from the associated engine, remove the propeller and inspect the mounting bolts and dowels, propeller attachment face and propeller shaft flange for signs of cracking or excessive fretting. When such indications are found, replace all mounting bolts and dowels with new items.\n\nCompliance: For Para. 1 \\- Within 10 hours time in service after 15 April 1969 unless previously accomplished.\n\nFor Para. 2 \\- At intervals not exceeding 100 hours time in service. For Para. 3 - As required.","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 a defined hardware combination. It has not expanded beyond its original purpose of ensuring propeller attachment integrity for the HC-A3VF/GTS10-520 configuration."},"complexity_factors":["Single, specific applicability (one propeller series, one engine series)","Only 3 procedural requirements with clear sequential logic","Minimal defined terms (only standard aviation terminology like 'time in service')","No cross-references to other legislation or regulations beyond the enabling authority","Straightforward compliance deadlines with no conditional exceptions","Total length: approximately 150 words"],"plain_english_summary":"This AD mandates replacement and recurring torque checks of propeller mounting hardware on Hartzell HC-A3VF propellers installed on Continental GTS10-520 engines to prevent in‑flight propeller separation. Operators must fit specified bolts and washers, torque them to 80–85 ft‑lb, and recheck torque every 100 flight hours; loose or damaged parts require removal and replacement. It addresses a known catastrophic failure risk."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope as written focuses on correcting and monitoring propeller attachment integrity for the specified propeller/engine combination. There is no indication in the text that it expands or narrows that original safety objective beyond prescribing replacement parts, torque, and inspection intervals."},"complexity_factors":["Narrow technical scope — applies only to HC‑A3VF propellers on Continental GTS10‑520 engines (straightforward applicability).","Specific hardware and numeric performance requirements — part numbers (A-1328-1, A-1381) and an exact torque range (80–85 lb·ft) reduce interpretive ambiguity.","Operational compliance timing — an urgent initial compliance window (10 hours) plus recurring 100‑hour inspection intervals adds scheduling pressure on operators.","Inspection-triggered escalation — one finding (substantial torque loss or rough running) requires propeller removal and detailed inspection, increasing maintenance complexity and potential downtime.","Safety‑critical context — although legally simple, the technical assessment and execution require qualified maintenance personnel and potential parts procurement logistics."],"plain_english_summary":"This airworthiness directive requires operators of HC‑A3VF propellers fitted to Continental GTS10‑520 engines to replace the propeller mounting bolts and washers with specified part numbers, apply a specified torque, and carry out recurring torque checks and inspections to detect loosening, fretting or cracking. It affects aircraft owners/operators and maintenance organisations, imposes short initial compliance time and recurring maintenance, and shifts parts and labour costs to operators to preserve attachment integrity."}},"importantCases":[],"_links":{"self":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection","history":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection/history","analysis":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection/analysis","conflicts":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection/conflicts","importantCases":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection/important-cases","documents":"/api/acts/ad-phzl-24-propeller-attachment-modification-and-inspection/documents"}}