{"id":"F2006B10439","name":"AD/HS 125/158 - APU Fuel Feed Hose Assemblies","slug":"ad-hs-125-158-apu-fuel-feed-hose-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116141,"registerId":"commonwealth-F2006B10439-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/158 - APU Fuel Feed Hose Assemblies","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)  \nBritish Aerospace BAe 125 Series Aeroplanes\n\nAD/HS 125/158 APU Fuel Feed Hose Assemblies 2/98\n\nApplicability: All BAe 125-800A and Hawker 800 series aircraft incorporating Mod 259404B (Introduction of Turbomach APU).\n\nRequirement 1. Inspect the APU fuel feed hose assembly, in accordance with Hawker Raytheon Corporate Jets Mandatory Inspection Service Bulletin SB 49-45.\n\nNote: FAA AD 97 21-03 refers.\n\n2. Replace the vinyl conduit on the APU fuel feed hose assembly with convoluted PTFE tube, in accordance with Hawker Service Bulletin SB.49-47-25A825A (Modification No. 25A825A).\n\nCompliance: 1. Unless previously accomplished, within 75 days of the effective date of this Directive.\n\n2. Within 200 flight hours of the effective date of this Directive.\n\nCompliance with Requirement 2 provides terminating action for the inspection in Requirement 1.\n\nThis airworthiness directive becomes effective on 29 January 1998.\n\nBackground: The aircraft manufacturer has advised that APU feed hoses have sustained heat damage due to impingement of hot bleed air leaking from adjacent pneumatic components.\n\nComplete failure of the APU hoses could result in an in-flight fire.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft models. It has not expanded beyond its original purpose of mandating hose inspection and replacement to prevent fire hazards."},"complexity_factors":["Very short document (under 300 words)","Only 2 substantive requirements with clear deadlines","Minimal defined terms (only 'Mod' and standard aviation abbreviations like APU, PTFE)","No nested exceptions or conditional logic","Simple cross-reference structure (references to 2 Service Bulletins and 1 FAA AD for context only)","Clear terminating action (Requirement 2 satisfies Requirement 1)"],"plain_english_summary":"Owners/operators of certain British Aerospace BAe 125-800A / Hawker 800 series jets fitted with the Turbomach APU must act to prevent hot-air damage to APU-area fuel hoses that could lead to an in‑flight fire. CASA requires prompt inspection and replacement of vulnerable vinyl hose covers with PTFE within tight time limits; completing the replacement ends further inspections. This mandatory AD took effect 29 January 1998 and targets aircraft with Modification 259404B installed."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive targets a specific subset of BAe/Hawker aircraft fitted with Mod 259404B and prescribes inspection then replacement; the text shows no indication the scope was altered from that defined in the instrument itself."},"complexity_factors":["Narrow applicability: applies only to BAe 125-800A and Hawker 800 aircraft with Mod 259404B (specific fleet subset).","Two-step compliance with different deadlines (inspection within 75 days; replacement within 200 flight hours).","Cross-references to external documents: Hawker Mandatory Inspection Service Bulletin SB 49-45, Hawker Service Bulletin SB.49-47-25A825A, and FAA AD 97 21-03 (operators must obtain and follow these).","Technical maintenance action: replacement of vinyl conduit with convoluted PTFE tube (requires parts and maintenance capability).","Terminating action provision: completing Requirement 2 terminates Requirement 1, creating sequencing incentives for operators.","Operational scheduling impact: timing tied to calendar days and flight hours, affecting maintenance planning."],"plain_english_summary":"*AD/HS 125/158 requires inspection and a one‑time conduit replacement on APU fuel feed hose assemblies.* Operators of BAe 125‑800A and Hawker 800 aircraft fitted with Mod 259404B must inspect the APU feed hose within 75 days and replace the vinyl conduit with convoluted PTFE tube within 200 flight hours; the replacement ends the inspection requirement. The manufacturer reports heat damage from leaking hot bleed air that could cause hose failure and in‑flight fire. Operators pay for and schedule the maintenance and must follow specified Hawker service bulletins."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies","history":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies/history","analysis":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies/analysis","conflicts":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies/conflicts","importantCases":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies/important-cases","documents":"/api/acts/ad-hs-125-158-apu-fuel-feed-hose-assemblies/documents"}}