{"id":"F2006B06174","name":"AD/PFP/16 - Ken Brock Propeller Hub Extension","slug":"ad-pfp-16-ken-brock-propeller-hub-extension","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47016,"registerId":"commonwealth-F2006B06174-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PFP/16 - Ken Brock Propeller Hub Extension","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 - Fixed Pitch\n\n \n\nAD/PFP/16 Ken Brock Propeller Hub Extension 3/91\n\nApplicability: Any propeller hub extender supplied by Ken Brock and fitted to any Lycoming 0-320 or 0-360 powered amateur built aircraft.\n\n \n\nRequirement: 1. Remove propeller from hub extender and measure extender wall thickness.\n\n \n\n2. If wall thickness is approximately 12 mm (.50 inches) refit propeller. If wall thickness is approximately 7 mm (.25 inches) replace hub extender before further flight.\n\n \n\nCompliance: At next scheduled aircraft inspection or by 31 July 1991, whichever occurs first.\n\n \n\nBackground: Due to insufficient wall thickness a hub extender supplied by Ken Brock has suffered a fatigue failure.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1331},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive remains precisely focused on its original purpose of addressing the specific fatigue failure risk identified in Ken Brock propeller hub extenders."},"complexity_factors":["Single measurement required (wall thickness)","Binary decision pathway with only two possible outcomes","Narrow applicability limited to specific manufacturer, engine models, and aircraft category","No cross-references to other legislative instruments","Simple compliance timeline with clear deadline"],"plain_english_summary":"**What this does:** This safety directive requires owners of certain home-built aircraft to inspect a specific part called a propeller hub extender (a spacer between the engine and propeller).\n\n**Who it affects:** Anyone who owns an amateur-built aircraft powered by a Lycoming O-320 or O-360 engine and uses a hub extender supplied by Ken Brock.\n\n**What you must do:**\n* Remove the propeller and measure the wall thickness of the hub extender\n* **If it's approximately 12mm thick:** Reassemble and continue flying\n* **If it's approximately 7mm thick:** Replace the part immediately before flying again\n\n**Why it matters:** The thinner hub extenders have suffered metal fatigue failures (cracking from repeated stress), which could cause the propeller to detach during flight—a potentially catastrophic failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension","history":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension/history","analysis":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension/analysis","conflicts":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension/conflicts","importantCases":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension/important-cases","documents":"/api/acts/ad-pfp-16-ken-brock-propeller-hub-extension/documents"}}