{"id":"F2006B06278","name":"AD/PMC/15 Amdt 1 - Propeller Attachment - Modification and Inspection","slug":"ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47325,"registerId":"commonwealth-F2006B06278-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PMC/15 Amdt 1 - 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 \\- McCauley\n\nAD/PMC/15\n\nAmdt 1\n\n  \n\nPropeller Attachment \\- Modification and Inspection\n\n  \n13/95\n\nApplicability: All model 3AF34C series propellers fitted to Continental GTSIO-520 engines.\n\nRequirement: 1. Remove and discard propeller mounting stud nuts and washers. Install new nuts (deleting the washers) and torque to 108-115 Nm (80-85 pounds feet) ensuring the threads on the nuts and studs are not lubricated and perfectly clean. New nuts shall be used each time a propeller is re-installed. Remove any torque value decal from the hub ensuring removal technique does not damage the hub.\n\n    2. Check for loss of torque on the propeller mounting stud nuts by applying a measured torque 108-115 Nm (80-85 pounds feet). Remove any torque value decal from the hub ensuring removal technique does not damage the hub.\n\n    3. In the event of any substantial loss of torque of the mounting stud nuts being found or of excessive rough running being experienced by the associated engine, remove the propeller and inspect the mounting studs and dowels, propeller attachment face and propeller shaft flange for signs of cracking or excessive fretting. When such indications are found, replace all mounting studs and dowels with new items. Ensure all threads are kept perfectly clean of lubricant. Repair or replace other damaged components as necessary. Remove any torque value decal from the hub ensuring removal technique does not damage the hub.\n\nCompliance: 1 Unless previously carried out within 10 hours time in service after 7 December 1995.\n\n    2. At intervals not exceeding 100 hours time in service.\n\n    3. As required.\n\nBackground: This amendment being raised to retain the non lubricated torque requirements on the threads of McCauley 3AF34C series propellers which differ from the requirements specified in McCauley SL 1992-18B. The requirement to apply a dry thread torque only applies to these propellers when they are fitted to the Continential GTSIO-520 engine powered aircraft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment preserves and clarifies an existing requirement to use non‑lubricated thread torque for 3AF34C propellers when installed on Continental GTSIO‑520 engines (Background; Applicability). It does not broaden affected models or impose obligations beyond the specified replacement, torque and inspection duties."},"complexity_factors":["Narrow technical applicability: limited to McCauley 3AF34C series propellers fitted to Continental GTSIO‑520 engines (Applicability).","Specific torque and installation procedure required (non‑lubricated threads, 108–115 Nm) — precision critical and safety‑sensitive (Requirement 1).","Recurring inspection obligation at fixed flight‑hour intervals (every 100 hours) creates ongoing compliance and record/maintenance scheduling (Compliance 2).","Mandatory parts replacement on re‑installation (new nuts each time) increases material costs and inventory control (Requirement 1).","Inspection triggers tied to performance symptoms (torque loss or rough running) introduce judgment calls for maintenance personnel and potential additional repairs (Requirement 3).","Deviation from manufacturer service letter (McCauley SL 1992‑18B) for this installation increases regulatory specificity and may require operators to track differences (Background)."],"plain_english_summary":"Mandates specific fastening and inspection practices for McCauley 3AF34C propellers when fitted to Continental GTSIO‑520 engines: replace stud nuts (no washers), install dry (unlubricated) nuts torqued to 108–115 Nm, perform torque checks every 100 flight hours, and inspect/replace studs or dowels if torque loss or rough running are found. Affects aircraft owners/operators and maintenance personnel who pay for replacement parts and labour and must follow the specified torque, inspection intervals and non‑lubricated‑thread procedure."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific mechanical incompatibility between McCauley 3AF34C propellers and Continental GTSIO-520 engines. The amendment (Amdt 1) merely clarifies and retains the dry torque requirement that differs from manufacturer guidance. It has not expanded beyond its original safety purpose of preventing propeller detachment."},"complexity_factors":["Single, specific applicability (one propeller series, one engine type)","Only 3 numbered requirements with clear, sequential steps","No defined terms section or interpretation provisions","No cross-references to other legislation or regulations","Simple compliance structure: one-time action + recurring inspection + conditional action","Plain language throughout with technical terms explained in context (e.g., 'dry thread torque')","Background section provides clear rationale without legal caveats"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of aircraft with McCauley 3AF34C propellers on Continental GTSIO-520 engines to change the propeller mounting practice to prevent in‑flight propeller loss. It mandates replacing the old nuts and washers, installing specified nuts tightened to 108–115 Nm using dry (unlubricated) threads, removing misleading torque labels, and performing recurring 100‑hour checks and inspections if loosening or rough running occurs.\n\nIt matters because lubrication alters clamp force and was judged unsafe for this propeller‑engine combination."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection","history":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection/history","analysis":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection/analysis","conflicts":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection/conflicts","importantCases":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection/important-cases","documents":"/api/acts/ad-pmc-15-amdt-1-propeller-attachment-modification-and-inspection/documents"}}