{"id":"F2006B09757","name":"AD/F28/20 - Powerplant Controls in Nacelle - Replacement of Washers","slug":"ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54621,"registerId":"commonwealth-F2006B09757-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F28/20 - Powerplant Controls in Nacelle - Replacement of Washers","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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Fokker F28 Series Aeroplanes\n\n \n\nAD/F28/20  Powerplant Controls in NK Nacelle - Replacement of Washers\n\n \n\nApplicability: Aircraft S/Nos. For SB Part 1 - S/Nos. 11003 to 11024 and 11991 to 11993. For SB Part 2 - S/Nos. 11003 to 11026 and 11991 to 11993.\n\n \n\nDocument: Fokker F28 SB No. 76-8.\n\n \n\nCompliance: Within 100 hours time in Service after 31 December 1971.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The excerpt sets a specific, limited requirement (washer replacement) for clearly identified serial-numbered aircraft and prescribes a compliance window. The text contains no indication that the scope of affected aircraft or required action was changed from an earlier or original intent; therefore there is no evidence in this document extract that the scope has been changed."},"complexity_factors":["Very short, single-action requirement (replacement of washers) limited to a clearly enumerated set of aircraft serial numbers (Applicability).","Compliance is time-limited and dated (within 100 hours TIS after 31 December 1971), which is precise but historically anchored (Compliance).","Technical compliance is delegated to an external document (Fokker F28 SB No. 76-8), so legal text is simple but requires consulting the service bulletin for procedural detail (Document).","The AD excerpt does not specify enforcement, exemptions or alternative compliance routes, creating potential operational ambiguity for implementers about approvals or penalties (absence noted in Document; Compliance).","Slight variation in applicability between SB Part 1 and Part 2 (different upper serial-number ranges) adds a small layer of administrative checking for operators (Applicability)."],"plain_english_summary":"This airworthiness directive requires owners/operators of the specified Fokker F28 serial numbers to replace washers in the NK nacelle powerplant control system per Fokker F28 Service Bulletin No. 76-8, within 100 hours TIS after 31 December 1971. Issued by the Civil Aviation Safety Authority, the work follows the manufacturer’s procedure and the operators bear parts, labour and downtime costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted Airworthiness Directive from 1971 addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating washer replacement in powerplant controls for specific Fokker F28 aircraft."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 4 operative provisions: applicability, document reference, compliance deadline, and subject matter","No defined terms section","No cross-references to other legislation beyond the enabling regulations (Civil Aviation Regulations 1998, Part 39)","Simple conditional logic: if your aircraft serial number matches the list, you must comply","Single compliance trigger (100 hours time in service after fixed date)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:**\nOrders owners and operators of specific Fokker F28 series aircraft to replace certain washers in the engine (powerplant) controls located in the nacelle (the streamlined housing that holds the engine on the wing).\n\n**Who it affects:**\nSpecific Fokker F28 aircraft with serial numbers:\n- For Service Bulletin Part 1: Serial numbers 11003 to 11024 and 11991 to 11993\n- For Service Bulletin Part 2: Serial numbers 11003 to 11026 and 11991 to 11993\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. If you own or operate one of these aircraft, you **must** complete this washer replacement within 100 hours of flight time after 31 December 1971. The directive references Fokker Service Bulletin No. 76-8, which contains the technical details of the required fix. Failure to comply means the aircraft cannot legally fly in Australian airspace.\n\n**In short:** This is a targeted mechanical fix for a specific safety issue on a narrow set of Fokker F28 aircraft, with a hard deadline measured in flight hours."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers","history":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers/history","analysis":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers/analysis","conflicts":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers/conflicts","importantCases":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers/important-cases","documents":"/api/acts/ad-f28-20-powerplant-controls-in-nacelle-replacement-of-washers/documents"}}