{"id":"F2006B06284","name":"AD/PMC/28 - Propeller Hub - Replacement","slug":"ad-pmc-28-propeller-hub-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47345,"registerId":"commonwealth-F2006B06284-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PMC/28 - Propeller Hub - Replacement","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 - McCauley\n\n \n\nAD/PMC/28 Propeller Hub - Replacement 10/75\n\nApplicability: Models D2AF34C52/80GF-0 and D2AF34C52A/ 80GF-0 with S/Nos. 63000 to 659999 which have not been modified in accordance with AD/PMC/20.\n\n \n\nDocument: McCauley SB No. 111.\n\n \n\nCompliance: For propellers which have completed 1500 hours total time in service as at 28 November 1975 - within 100 hours time in service after 28 November 1975. For propellers with less than 1500 hours total time in service -before achieving 1600 hours total time in service.\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\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 known defect in specific propeller models. It has not expanded beyond its original purpose of mandating hub replacement for safety-critical fatigue or structural issues in the identified serial number range."},"complexity_factors":["Extremely short document (approximately 150 words of substantive content)","Only 2 defined applicability criteria (model numbers and serial number range)","Single cross-reference to prior directive AD/PMC/20","Simple binary compliance structure (two categories based on flight hours)","No nested exceptions or conditional logic beyond the applicability exclusion","Single external document reference (McCauley SB No. 111) with no incorporation by reference complexity","No interpretation section or defined terms"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice for aircraft parts, but with legal force.\n\n**What it requires:** Owners and operators of specific McCauley variable-pitch propellers must replace the propeller hub (the central component that connects the blades to the aircraft engine).\n\n**Who it affects:** Specifically targets two McCauley propeller models:\n- D2AF34C52/80GF-0\n- D2AF34C52A/80GF-0\n\nOnly those with serial numbers between 63000 and 659999, **and** only if they haven't already been fixed under a previous directive (AD/PMC/20).\n\n**When it must be done:**\n- **High-time propellers** (already flown 1,500+ hours by 28 November 1975): Replace within 100 hours of flying time after that date\n- **Lower-time propellers** (under 1,500 hours by 28 November 1975): Replace before hitting 1,600 total hours\n\n**Why it matters:** This directive addresses a specific safety defect in these propeller hubs. Failure to comply could lead to catastrophic propeller failure in flight. The reference to McCauley Service Bulletin No. 111 suggests the manufacturer identified a structural or fatigue issue requiring mandatory replacement rather than repair.\n\n**The bottom line:** If you're flying one of these specific propellers, you legally cannot keep operating beyond the specified flight hours without replacing the hub. This is non-negotiable aviation safety law."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text specifies a targeted replacement requirement for identified propeller models and serial numbers and excludes units already modified under AD/PMC/20 (Applicability). There is no language in the instrument indicating an expansion or narrowing of that population beyond the stated models, serial numbers and modification exception; the compliance timing rules are those set out in the directive (Compliance; Document). Therefore there is no apparent change of scope within the text provided."},"complexity_factors":["Narrow technical scope: applies only to two specific propeller models and a defined serial‑number range (Applicability).","Exception clause: excludes units already modified under AD/PMC/20, requiring cross‑checking of prior compliance (Applicability).","Time-based compliance rules require calculating total time in service as at a fixed calendar date and applying two different deadlines (1500+ hours as at 28 Nov 1975 → within 100 hours; <1500 hours → before 1600 hours) (Compliance).","Dependence on an external technical document (McCauley Service Bulletin No. 111) for the procedural steps introduces operational dependency on manufacturer instructions (Document).","Regulatory placement under Part 39 ties the AD to the broader airworthiness enforcement regime, which operators must follow (Header)."],"plain_english_summary":"This Airworthiness Directive mandates replacement of the propeller hub on McCauley variable‑pitch propellers models D2AF34C52/80GF‑0 and D2AF34C52A/80GF‑0 (S/N 63000–659999) unless already modified per AD/PMC/20, using McCauley Service Bulletin No. 111.\n\nTiming: units with ≥1,500 hours as of 28 Nov 1975 must be replaced within 100 flight hours; units with <1,500 hours must be replaced before 1,600 hours. Owners/operators must arrange and fund compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pmc-28-propeller-hub-replacement","history":"/api/acts/ad-pmc-28-propeller-hub-replacement/history","analysis":"/api/acts/ad-pmc-28-propeller-hub-replacement/analysis","conflicts":"/api/acts/ad-pmc-28-propeller-hub-replacement/conflicts","importantCases":"/api/acts/ad-pmc-28-propeller-hub-replacement/important-cases","documents":"/api/acts/ad-pmc-28-propeller-hub-replacement/documents"}}