{"id":"F2006B10485","name":"AD/HS 125/46 - Fuel Filter De-Icing Pumps - Replacement","slug":"ad-hs-125-46-fuel-filter-de-icing-pumps-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116233,"registerId":"commonwealth-F2006B10485-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/46 - Fuel Filter De-Icing Pumps - 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)  British Aerospace BAe 125 Series Aeroplanes\n\n \n\nAD/HS 125/46 Fuel Filter De-Icing Pumps - Replacement 5/77\n\nApplicability: As detailed in the requirement document. Document: Hawker Siddeley SB 28-A63.\n\nCompliance: Within 100 hours time in service after 31 May 1977.\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\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1977 addressing a specific component defect. It has not expanded beyond its original scope of requiring fuel filter de-icing pump replacement on BAe 125 aircraft."},"complexity_factors":["Extremely short document (under 150 words)","No defined terms section — uses plain operational language","Single, clear compliance action (replacement of specific component)","Simple temporal trigger (100 hours time in service after fixed date)","No nested exceptions or conditional logic","Cross-reference to only one external technical document (Hawker Siddeley SB 28-A63)","No internal cross-references to other legislation sections"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific British Aerospace BAe 125 series aircraft to replace their fuel filter de-icing pumps.\n\n**Who it affects:**\n- Operators of British Aerospace BAe 125 series aeroplanes\n- Maintenance organisations servicing these aircraft\n\n**What it requires:**\n- Replace the fuel filter de-icing pumps on affected aircraft\n- Follow the technical instructions in **Hawker Siddeley Service Bulletin 28-A63** (the 'requirement document')\n- Complete the work **within 100 hours of flying time** after 31 May 1977\n\n**Why it matters:**\nFuel filter de-icing pumps prevent ice from blocking fuel filters at high altitudes or cold temperatures. A failed pump could cause engine fuel starvation, potentially leading to engine failure. This AD addresses a known safety defect before it causes accidents.\n\nAirworthiness Directives are legally binding — compliance is not optional. Aircraft cannot legally fly if they don't meet AD requirements."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text of the AD sets a single mandatory action (replace fuel filter de-icing pumps) for aircraft identified in the referenced service bulletin and specifies a compliance deadline. There is no indication in the AD that it amends or narrows an earlier instrument or changes an original intent; it simply prescribes the replacement per Hawker Siddeley SB 28-A63 with the stated 100-hour compliance window."},"complexity_factors":["Short, single-action requirement (replacement of a component) reduces interpretive complexity.","Clear, specific compliance deadline: \"Within 100 hours time in service after 31 May 1977\".","Applicability is not included in the AD itself and is delegated to an external document (Hawker Siddeley SB 28-A63), requiring consultation of that bulletin to determine whether a specific aeroplane is affected.","No technical detail or procedure in the AD; implementers must obtain the service bulletin for instructions and parts, adding a lookup step.","Historic date and minimal text mean modern traceability may require locating archived service bulletins, which can add practical complexity."],"plain_english_summary":"This AD requires replacement of the fuel filter de‑icing pumps on British Aerospace BAe 125 aeroplanes, to be carried out per Hawker Siddeley Service Bulletin SB 28‑A63 within 100 hours TIS after 31 May 1977.  \n\nIt places the cost and scheduling burden on aircraft owners/operators, who must consult the service bulletin to determine if their aircraft are affected and to obtain the technical details for compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement","history":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement/history","analysis":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement/analysis","conflicts":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement/conflicts","importantCases":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement/important-cases","documents":"/api/acts/ad-hs-125-46-fuel-filter-de-icing-pumps-replacement/documents"}}