{"id":"F2006B09876","name":"AD/F50/49 - Windshield Wiper Rotary Selector Switch Replacement","slug":"ad-f50-49-windshield-wiper-rotary-selector-switch-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54994,"registerId":"commonwealth-F2006B09876-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/49 - Windshield Wiper Rotary Selector Switch 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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n \n\n# AD/F50/49  Windshield Wiper Rotary Selector Switch Replacement\n\nApplicability: All F27 Mk 50 aircraft serial numbers 20103 to 20199 inclusive. Requirement: Action in accordance with Fokker Service Bulletin F50-30-012 Revision 1.\n\nNote: Netherlands AD 91-123 also refers.\n\n \n\nCompliance: Prior to 2 March 1992.\n\n \n\nBackground: Fokker have advised that certain windshield wiper rotary selector switches\n\n# 1/92\n\nmanufactured by Marquette are prone to burn out. This may cause damage to the electrical wiring, insulation material and pitot static lines, and may also result in smoke on the flight deck.\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 AD applies to a specific set of F27 Mk 50 serial numbers and requires replacement of the windshield wiper rotary selector switch per Fokker Service Bulletin F50-30-012 Revision 1 by a fixed date. The instrument’s scope as presented is limited and prescriptive; there is no indication in the text supplied that the scope was changed from that original requirement."},"complexity_factors":["Narrow, clearly defined applicability by serial-number range (Applicability)","Single, specific required action referenced to one service bulletin (Requirement)","Fixed compliance deadline (Compliance)","Technical detail delegated to external document (Fokker Service Bulletin F50-30-012 Rev 1) rather than contained in the AD (Requirement)","No cost allocation or procedural restrictions specified in the AD (silence increases operational questions but not legal complexity) (Requirement; Compliance)","Cross-reference to another authority's AD (Netherlands AD 91-123) adds minor coordination factor (Note)"],"plain_english_summary":"What this instrument requires (mechanical change first):\n\n- It requires replacement of the windshield wiper rotary selector switch on certain Fokker F50 (F27 Mk 50) aeroplanes. The replacement must be carried out in accordance with Fokker Service Bulletin F50-30-012 Revision 1. (Requirement)\n- The replacement must be completed before 2 March 1992. (Compliance)\n\nWho is affected:\n\n- The rule applies only to F27 Mk 50 aircraft with serial numbers 20103 through 20199 inclusive. (Applicability)\n- The document does not name a specific party to pay for the work, but it places an obligation on the operators/owners of the affected aircraft to have the action done by the compliance date. (Applicability; Requirement; Compliance)\n\nWhy it matters (official rationale and technical risk):\n\n- Fokker advised that certain windshield wiper rotary selector switches manufactured by Marquette are prone to burn out. The burn-out can cause damage to electrical wiring, insulation material and pitot-static lines, and may produce smoke on the flight deck. The AD is issued to remove that identified safety risk by replacing the affected switch. (Background)\n\nPractical mechanics, costs and compliance implications:\n\n- The AD prescribes a specific technical remedy by reference to a Fokker service bulletin (F50-30-012 Rev 1). Operators must follow that bulletin to meet the AD’s requirement. (Requirement)\n- The AD sets a fixed compliance deadline (prior to 2 March 1992). This imposes a time-bound maintenance obligation on affected aircraft. (Compliance)\n- The AD itself does not allocate costs, reimbursements, or exemptions. It also does not specify who is authorised to perform the replacement or supply the parts. Those details would be determined by the service bulletin or normal commercial/maintenance arrangements. (Requirement; Compliance)\n\nImplementation risks, incentives and trade-offs (source-grounded):\n\n- Implementation depends on access to the specified service bulletin and the replacement parts it describes. If parts or approved procedures are limited, operators may face scheduling pressure to meet the deadline. (Requirement; Compliance)\n- The AD removes operator discretion to ignore the defect: it mandates replacement per the service bulletin by the date given. It does not, on its face, permit an alternative corrective action or deferral in the text provided. (Requirement; Compliance)\n- The document cross-references a Netherlands airworthiness directive (Netherlands AD 91-123), indicating the same defect has been addressed by another authority; the AD does not describe any harmonised compliance mechanism beyond referring to those documents. (Note)\n\nWho decides, who pays, and what changes in behaviour:\n\n- The Civil Aviation Safety Authority (via the AD) decides the safety action and deadline. (Requirement; Compliance)\n- The AD requires operators of the specifically listed serial-number aircraft to arrange and complete the replacement before the stated date. The AD does not state who bears financial cost; the text is silent on cost allocation. (Applicability; Requirement; Compliance)\n- Operators must plan maintenance and parts procurement to meet the deadline; they must apply the procedures in the referenced Fokker service bulletin. (Requirement; Compliance)\n\nConcise summary of limits and open points in the instrument:\n\n- The AD is narrowly targeted by serial number rather than all F50s. (Applicability)\n- The remedy is specified by reference to a Fokker service bulletin; the AD does not itself set technical steps. (Requirement)\n- The AD identifies the hazard (burn out, wiring/pitot-static damage, smoke) but does not address cost, who will supply parts, or who performs the work. Those operational details are left to operators and the service bulletin. (Background; Requirement)\n\nSource citations: Applicability; Requirement; Compliance; Note; Background."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive focused specifically on a defective windshield wiper switch. It has not expanded beyond its original purpose of addressing the Marquette switch burnout hazard."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined applicability criterion (aircraft serial number range)","Single, unambiguous compliance action (replace switch per specified service bulletin)","No nested exceptions, conditional logic, or cross-references to other legislation","One external reference (Netherlands AD 91-123) noted for information only","Clear, fixed compliance date with no alternative methods or escalations"],"plain_english_summary":"**What this is:** 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:** It requires owners and operators of specific Fokker F50 aircraft (serial numbers 20103 to 20199) to replace faulty windshield wiper rotary selector switches. The replacement must follow instructions in Fokker Service Bulletin F50-30-012 Revision 1.\n\n**Why it matters:** The original switches, made by Marquette, are prone to burning out. This isn't just an inconvenience — it can damage electrical wiring, insulation, and pitot-static lines (tubes that feed critical flight instruments like airspeed indicators). It can also cause smoke in the cockpit, creating a serious flight safety hazard.\n\n**Who must act:** Anyone operating the affected Fokker F50 aircraft.\n\n**Deadline:** The work had to be completed before 2 March 1992.\n\n**Key point:** This is a **retrospective safety mandate** — it applies to aircraft already in service and forces a fix for a known design defect."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement","history":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement/history","analysis":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement/analysis","conflicts":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement/conflicts","importantCases":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement/important-cases","documents":"/api/acts/ad-f50-49-windshield-wiper-rotary-selector-switch-replacement/documents"}}