{"id":"F2006B09842","name":"AD/F50/17 - Fuel Collector Tank Supply Line","slug":"ad-f50-17-fuel-collector-tank-supply-line","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54887,"registerId":"commonwealth-F2006B09842-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/17 - Fuel Collector Tank Supply Line","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nFokker F50 (F27 Mk 50) Series Aeroplanes\n\nAD/F50/17 Fuel Collector Tank Supply Line 5/89\n\nApplicability: Model F27 Mark 050 with serial numbers 20104 through 20108.\n\nRequirement: 1. Inspect the fuel collector tank supply line (fwd line looking in the direction of flight) and the sheepskin \\- covered edges of the feedthrough holes at STA 3038 of both engine nacelles for evidence of chafing.\n\n2. Action in accordance with Fokker 50 SB No. F50-28-003.\n\nNote: RLD AD BLA 89-18 refers.\n\nCompliance: 1. Within 65 hours time in service after 31 May 1989, until modified in accordance with Fokker 50 SB No. F50-28-003.\n\n2. Prior to 31 August 1989.\n\nBackground: The manufacturer has determined that a modification to enlarge the STA 3038 nacelle feedthrough hole and fit ant-chafe material to the fuel supply line, will eliminate interference and possible fuel leakage.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific mechanical defect in a small fleet of aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific aircraft model and narrow serial number range (5 aircraft total)","Two straightforward inspection requirements with clear physical locations (STA 3038, specific fuel line)","Single cross-reference to manufacturer service bulletin","Simple compliance timeline with two alternative deadlines","No defined terms section, no nested conditions, no exceptions","Background explanation provided in plain language"],"plain_english_summary":"This is a **safety directive for specific Fokker F50 aircraft** (serial numbers 20104-20108). It requires airlines or aircraft operators to **inspect fuel lines near the engines** for wear and tear (chafing) where they pass through the aircraft structure. If problems are found, operators must follow the manufacturer's repair instructions (Service Bulletin F50-28-003). The directive was issued because the manufacturer discovered that fuel lines could rub against metal edges, potentially causing dangerous fuel leaks. Operators had to complete inspections by late 1989 and ongoing checks until permanent repairs were made."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The source document sets a narrowly targeted corrective requirement for specific serial-numbered aircraft. It does not indicate any amendment that expands or reduces the AD’s applicability or duties beyond what is stated in the Applicability, Requirement and Compliance sections."},"complexity_factors":["Narrow applicability limited to five specific aircraft serial numbers (Applicability)","Two discrete technical actions: inspection for chafing and modification per a manufacturer service bulletin (Requirement)","Two compliance time constraints: inspection within 65 hours after 31 May 1989 (and until modified) and modification before 31 August 1989 (Compliance)","Dependency on an external manufacturer Service Bulletin (F50-28-003) for the exact corrective work (Requirement; Background)","Reference to another AD (RLD AD BLA 89-18) for related material (Note)"],"plain_english_summary":"### What this instrument does\n\nThis Airworthiness Directive (AD) orders operators of a small set of Fokker F50 aeroplanes to check and, where necessary, modify a fuel supply component to prevent chafing and possible fuel leakage. It applies only to F27 Mark 050 aeroplanes with serial numbers 20104 through 20108 (Applicability). The AD requires: 1) an inspection of the forward fuel collector tank supply line and the sheepskin-covered edges of the STA 3038 feedthrough holes in both engine nacelles for signs of chafing, and 2) carrying out the corrective modification described in Fokker 50 Service Bulletin No. F50-28-003 (Requirement). The manufacturer says the modification enlarges the feedthrough hole and fits anti-chafe material to remove the interference that can cause leakage (Background).\n\n### Who is affected and who pays\n\n- Affected: Operators (owners and maintainers) of the five identified serial-numbered aircraft (Applicability). \n- Who pays: The operator of each affected aeroplane must carry out the inspection and the modification required by the AD. The AD itself does not allocate funding or suppliers; costs for labour, parts and aircraft downtime are therefore borne by those operators (Requirement; Compliance).\n\n### What must be done and by when\n\n- Inspection: Conduct the specified inspection of the forward fuel collector tank supply line and the sheepskin-covered feedthrough edges at STA 3038 of both engine nacelles within 65 hours time-in-service after 31 May 1989, and continue to comply with that inspection requirement until the aeroplane has been modified as directed by the Fokker service bulletin (Compliance). \n- Modification: Complete the modification in accordance with Fokker 50 Service Bulletin F50-28-003 before 31 August 1989 (Requirement; Compliance). \n\n### Who decides and how the rule is implemented\n\n- The Civil Aviation Safety Authority (CASA) issued the AD (header). The specific corrective action the AD mandates is implemented by following the manufacturer’s service bulletin (Requirement; Background).\n\n### Practical effects, incentives and implementation considerations\n\n- Behavioural change: Operators must prioritise inspection and modification work for the five affected aircraft within the stated time windows and may keep an aircraft on inspection cycles until the modification is completed (Requirement; Compliance).\n- Compliance burden: The work requires physical access to nacelle feedthroughs and replacement/installation of anti-chafe material and/or enlargement of the hole per the service bulletin. That creates direct labour, parts and aircraft-out-of-service time costs for operators (Requirement; Background). \n- Safety incentive: The manufacturer links the modification to the elimination of interference and possible fuel leakage; the AD enforces that technical correction (Background). \n- Scope and limits: The AD is narrowly focused on a specific component of five serial-numbered aeroplanes. It does not set prices, ownership rules, competitive conditions, or broader operational restrictions; it prescribes a technical inspection and a mandated modification (Applicability; Requirement).\n\n### Cross-references\n\n- The AD refers to a related RLD AD (BLA 89-18) for additional context (Note)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line","history":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line/history","analysis":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line/analysis","conflicts":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line/conflicts","importantCases":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line/important-cases","documents":"/api/acts/ad-f50-17-fuel-collector-tank-supply-line/documents"}}