{"id":"F2005L00602","name":"AD/HS 125/174 - Installing Insulating Blankets","slug":"ad-hs-125-174-installing-insulating-blankets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":112858,"registerId":"commonwealth-F2005L00602-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"British Aerospace BAe 125 Series Aeropla","sectionType":"division","heading":"British Aerospace BAe 125 Series Aeroplanes","content":"### British Aerospace BAe 125 Series Aeroplanes\n\n| AD/HS 125/174 | Installing insulating blankets | 4/2005 |\n| ------------- | ------------------------------ | ------ |\n\n| Applicability: | Raytheon model aeroplanes listed below and identified in Raytheon Service Bulletin SB 26-3496, dated November 2003, equipped with TFE731 engines:                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n|                | DH.125, HS.125 and BH.125 seriesBAe.125 series 800A (C-29A and U-125) and 800BHawker 800 (including variant U-125A), andHawker 800XP                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Requirement:   | Install insulating blankets on the engine compartment firewall and the wire harness passing through the firewall fairlead in accordance with the Accomplishment Instructions of SB 26-3496.                                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | Note: FAA AD 2005-03-16 Amdt 39-13972.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| Compliance:    | Within 12 months after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n|                | This Airworthiness Directive becomes effective on 14 April 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| Background:    | The United States Federal Aviation Administration (FAA) has received a report indicating that insulation on the wire harness passing through the firewall fairlead ignited on the fuselage side of the firewall. This Directive requires the installation of insulating blankets on the engine compartment firewall and the wire harness passing through the firewall fairlead. The Directive is issued to prevent a fire in the engine compartment from causing possible ignition of outgassing wire insulation on the fuselage side of the firewall, which could lead to an uncontrollable fire in the fuselage. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n3 March 2005","sortOrder":0},{"sectionNumber":"AD/HS 125/174","sectionType":"part","heading":"AD/HS 125/174","content":"## AD/HS 125/174","sortOrder":1},{"sectionNumber":"Installing insulating blankets","sectionType":"part","heading":"Installing insulating blankets","content":"## Installing insulating blankets","sortOrder":2},{"sectionNumber":"4/2005","sectionType":"part","heading":"4/2005","content":"## 4/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific safety defect in specific aircraft models. It has not expanded beyond its original purpose of mandating a particular safety modification."},"complexity_factors":["Very short document (approximately 250 words)","Only 4 defined elements: applicability (aircraft models), requirement (action), compliance deadline, and background","Single cross-reference to FAA AD 2005-03-16 and Raytheon Service Bulletin SB 26-3496","No nested conditions or exceptions — straightforward 'if your aircraft is on this list, do this action by this date' structure","Clear, unambiguous compliance deadline (12 months from effective date)"],"plain_english_summary":"This AD mandates that owners/operators of specified British Aerospace BAe 125 series (Hawker 800/800XP etc.) fitted with TFE731 engines install insulating blankets on the engine‑compartment firewall and on wire harnesses passing through it. It responds to a fire risk where wiring could ignite on the cabin side of the firewall and spread into the cabin. Compliance requires installation per Raytheon Service Bulletin SB 26‑3496 within 12 months of 14 April 2005; the AD is legally binding."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive's scope mirrors the FAA report and the Raytheon service bulletin cited: it applies only to the BAe 125 series aeroplanes identified in SB 26-3496 equipped with TFE731 engines and mandates installing insulating blankets. The instrument does not expand applicability beyond the models or the hazard described in the source text."},"complexity_factors":["Narrow, model- and engine-specific applicability (BAe 125 series identified in SB 26-3496) reduces scope complexity.","Requires a technical installation in accordance with an external manufacturer Service Bulletin (SB 26-3496), so compliance depends on following detailed technical instructions.","Cross-reference to an FAA Airworthiness Directive creates dependency on an external regulatory document.","Fixed compliance timeframe (within 12 months) affects operational scheduling and maintenance planning.","Costs and procurement of insulating blankets and installation labour are borne by aircraft owners/operators.","Regulatory enforcement and the effective date are set by the Civil Aviation Safety Authority; limited administrative discretion evident from the Directive text.","Safety-critical subject matter increases oversight and potential certification checks despite straightforward mechanical requirements."],"plain_english_summary":"Requires owners/operators of specified BAe 125 series aeroplanes with TFE731 engines to install insulating blankets on the engine compartment firewall and the wire harness through the firewall fairlead, following Raytheon Service Bulletin SB 26-3496. Compliance is required within 12 months of the Directive's effective date.\n\nThe measure responds to an FAA report of wiring insulation ignition; its stated purpose is to stop an engine-compartment fire from igniting outgassed wire insulation on the fuselage side of the firewall. Aircraft operators bear the installation cost and must follow the service bulletin."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-174-installing-insulating-blankets","history":"/api/acts/ad-hs-125-174-installing-insulating-blankets/history","analysis":"/api/acts/ad-hs-125-174-installing-insulating-blankets/analysis","conflicts":"/api/acts/ad-hs-125-174-installing-insulating-blankets/conflicts","importantCases":"/api/acts/ad-hs-125-174-installing-insulating-blankets/important-cases","documents":"/api/acts/ad-hs-125-174-installing-insulating-blankets/documents"}}