{"id":"F2006B06383","name":"AD/PW100/4 - Fuel Pump Input Drive Shaft","slug":"ad-pw100-4-fuel-pump-input-drive-shaft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47668,"registerId":"commonwealth-F2006B06383-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PW100/4 - Fuel Pump Input Drive Shaft","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 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Pratt and Whitney Canada Turbine Engines - PW100 Series\n\n \n\nAD/PW100/4 Fuel Pump Input Drive Shaft 7/91\n\nApplicability: PW123, PW123AF, PW124B, PW125B, PW126 engines as detailed in Pratt and Whitney Canada Service Bulletin No. 20946 Rev. 1.\n\n \n\nRequirement: Action in accordance with the Technical Requirements of Transport Canada Airworthiness Directive No CF-91-02.\n\n \n\nCompliance: Prior to 31 October 1991.\n\n \n\nBackground:  The engine manufacturer has determined that fuel pump input drive shaft torsional vibration can induce oscillations of the main fuel control governor, which may result in large torque fluctuations or torque drop during flight. This Directive requires the modification of the fuel pump to incorporate an input drive shaft with increased torsional stiffness.\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":2612},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This directive remains precisely targeted at its original scope: correcting a specific mechanical vibration defect in fuel pump drive shafts. There is no evidence of expansion beyond the initial safety issue addressed in 1991."},"complexity_factors":["Single, unambiguous mechanical requirement with no exceptions or conditional logic","No defined terms, interpretation section, or internal cross-references","Applicability restricted to just five specific engine models","Relies on external technical document (Canadian directive) rather than complex internal provisions"],"plain_english_summary":"This is a mandatory safety instruction (called an **Airworthiness Directive**) issued by Australia's Civil Aviation Safety Authority for aircraft operators.\n\n**Who it affects:** Anyone operating aircraft with specific Pratt & Whitney Canada engines (models PW123, PW123AF, PW124B, PW125B, and PW126).\n\n**What it requires:** You must modify the engine's fuel pump by replacing the input drive shaft with a new version that has increased \"torsional stiffness\" (meaning it is more resistant to twisting and vibrating). The exact technical steps are found in Canadian aviation directive CF-91-02.\n\n**Why it matters:** The original drive shaft could vibrate during flight, causing dangerous fluctuations or sudden drops in engine power (torque). This fix prevents that safety risk.\n\n**When:** The modification had to be completed before 31 October 1991."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft","history":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft/history","analysis":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft/analysis","conflicts":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft/conflicts","importantCases":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft/important-cases","documents":"/api/acts/ad-pw100-4-fuel-pump-input-drive-shaft/documents"}}