{"id":"F2009L01966","name":"AD/HS 125/183 - Cockpit Ventilation and Avionics Cooling System Blower Motor","slug":"ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":79150,"registerId":"commonwealth-F2009L01966-current","compilationNumber":null,"startDate":"2026-04-02","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 125/183 | Cockpit Ventilation and AvionicsCooling System Blower Motor | 6/2009 |\n| ------------- | ----------------------------------------------------------- | ------ |\n\n| Applicability: | Hawker Beechcraft Corporation Model BH.125 series 600A aeroplanes and Model HS.125 series 700A aeroplanes, as identified in Hawker Beechcraft Mandatory Service Bulletin SB 24-3850, dated January 2008, which have been modified in accordance with United States Federal Aviation Administration (FAA) Supplemental Type Certificate SA2271SW.                                                                                    |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect the wiring diagrams pertaining to the cockpit blowers and compare with the current aeroplane configuration, in accordance with the Accomplishment Instructions of SB 24-3850.                                                                                                                                                                                                                                            |\n|                | 2. If the current aeroplane configuration does not match the applicable cockpit blower wiring diagrams, rework the wiring using a method approved by the Manager, Special Certification Office, ASW-190, Rotorcraft Directorate, FAA. For the determination to be approved by the Manager, Special Certification Office, as required by this paragraph, the Manager's approval letter must specifically refer to FAA AD 2009-08-04. |\n|                | 3. If the current aeroplane configuration matches the applicable cockpit blower wiring diagrams, rework the wiring in accordance with the Accomplishment Instructions of SB 24-3850.                                                                                                                                                                                                                                                |\n|                | Later revisions of the above SB, approved by the FAA as an Alternate Method of Compliance (AMOC) to FAA AD 2009-08-04, are considered acceptable for compliance with the equivalent Requirements of this Directive.                                                                                                                                                                                                                 |\n|                | Note: FAA AD 2009-08-04 Amdt 39-15877 refers.                                                                                                                                                                                                                                                                                                                                                                                       |\n| Compliance:    | For Requirement 1 - Within 600 hours time in service or six months after the effective date of this Directive, whichever occurs first.                                                                                                                                                                                                                                                                                              |\n|                | For Requirements 2 and 3 - Before further flight after the Requirement 1 inspection.                                                                                                                                                                                                                                                                                                                                                |\n|                | This Airworthiness Directive becomes effective on 4 June 2009.                                                                                                                                                                                                                                                                                                                                                                      |\n\n| Background: | The FAA has received a report indicating that a cockpit ventilation and avionics cooling system blower motor seized and gave off smoke.This Directive requires inspecting the wiring diagrams pertaining to the cockpit blowers and comparing with the current airplane configuration, together with any necessary reworking of the wiring. The Directive is issued to prevent smoke and fumes in the cockpit in the event that a blower motor seizes and overheats due to excessive current draw. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n24 April 2009","sortOrder":0},{"sectionNumber":"AD/HS 125/183","sectionType":"part","heading":"AD/HS 125/183","content":"## AD/HS 125/183","sortOrder":1},{"sectionNumber":"Cockpit Ventilation and AvionicsCooling ","sectionType":"part","heading":"Cockpit Ventilation and AvionicsCooling System Blower Motor","content":"## Cockpit Ventilation and Avionics  \nCooling System Blower Motor","sortOrder":2},{"sectionNumber":"6/2009","sectionType":"part","heading":"6/2009","content":"## 6/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This Directive implements the corrective actions described in the referenced FAA AD and service bulletin to mitigate the specific risk of a blower motor seizing and producing smoke/fumes. It is targeted at aircraft modified under STC SA2271SW and does not broaden the safety issue beyond that original technical scope. There is no material indication in the text that the Directive expands the subject beyond the original safety objective; it largely adopts the FAA action and sets compliance timings and an approval route for alternate methods."},"complexity_factors":["Short instrument but references external documents: Hawker Beechcraft Mandatory Service Bulletin SB 24-3850 (Jan 2008) and FAA AD 2009-08-04.","Applicability limited to aircraft modified under FAA STC SA2271SW (conditional scope).","Three-step requirement flow with branching: inspect, then two alternative rework paths depending on result (Requirements 1–3).","Requirement 2 requires an approval from a named FAA official and that the approval letter specifically reference FAA AD 2009-08-04 (adds administrative coupling to FAA processes).","Acceptance of later SB revisions if approved as FAA AMOC introduces deferred discretion and cross-jurisdictional update mechanism.","Compliance deadlines are two-tiered (600 flight hours or six months for inspection; before further flight for any rework)."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires operators of certain Hawker Beechcraft BAe 125 / HS.125 aeroplanes (see \"Who is affected\") to inspect the wiring diagrams for the cockpit ventilation and avionics cooling blower(s) and compare those diagrams with the aircraft’s actual wiring (Requirement 1).\n- If the aircraft wiring does not match the diagrams, the wiring must be reworked using a method approved by the FAA Manager, Special Certification Office (Requirement 2). The Manager’s approval letter must specifically refer to FAA AD 2009-08-04.\n- If the aircraft wiring does match the diagrams, the wiring must be reworked according to the instructions in Hawker Beechcraft Mandatory Service Bulletin SB 24-3850 (Requirement 3).\n- Later revisions of SB 24-3850 that the FAA approves as an Alternate Method of Compliance (AMOC) to FAA AD 2009-08-04 are acceptable for compliance with this Directive.\n\n**Who is affected**\n\n- Owners and operators of Hawker Beechcraft Corporation Model BH.125 series 600A and Model HS.125 series 700A aircraft that have been modified under FAA Supplemental Type Certificate SA2271SW and are identified in Hawker Beechcraft Mandatory Service Bulletin SB 24-3850 (January 2008).\n- Maintenance organisations, engineers and certificated personnel who must carry out the inspections and any required rewiring.\n\n**When the work must be done**\n\n- The wiring-diagram inspection must be completed within 600 flight hours or six months after the directive’s effective date, whichever comes first (Requirement 1).\n- Any necessary rewiring (Requirements 2 or 3) must be completed before the aeroplane’s next flight after the inspection.\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The stated purpose is to prevent smoke and fumes in the cockpit caused by a blower motor seizing and overheating due to excessive current draw. Mechanically, the Directive forces an inspection to identify potentially unsafe wiring configurations and requires corrective wiring work so the blower(s) cannot overheat under foreseeable electrical conditions (Background and Requirements).\n\n**Who pays, who decides, and what behaviour changes**\n\n- Owners/operators pay for the inspection and for any rewiring and associated aircraft downtime. (Requirements 1–3; Compliance.)\n- The FAA Manager, Special Certification Office (or an FAA-approved AMOC), decides whether a non-standard rework method is acceptable. CASA adopts the FAA AD reference for compliance under this Directive. (Requirement 2; AMOC provision.)\n- Behaviour changes required: inspect wiring diagrams vs actual wiring; rework wiring when diagrams and configuration differ; apply the service bulletin instructions where they match; obtain FAA approval for alternate rework methods.\n\n**Trade-offs, costs and implementation issues**\n\n- Direct costs: labour for inspection, possible rewiring labour and parts, and aircraft downtime while the work is completed (Compliance timing requires rework before further flight).\n- Administrative burden: if the aircraft configuration does not match the diagrams, operators must obtain FAA Manager approval for the rework method and ensure the approval letter references FAA AD 2009-08-04 (Requirement 2). This creates an approval step that can delay return-to-service.\n- Scope limit: only aircraft modified under STC SA2271SW and listed in SB 24-3850 are covered. Aircraft of the same type but without that STC are not in scope (Applicability).\n- Risk mitigation vs cost: the Directive targets a specific failure mode (blower motor seizing and overheating). The inspection-and-rework approach is intended to reduce the probability of in-flight cockpit smoke/fumes, but it imposes immediate compliance costs and potential operational disruption.\n- Implementation flexibility: acceptance of later SB revisions approved as AMOCs provides a path to use updated procedures without separate directive changes, reducing some administrative friction.\n\n**Concrete incentives and effects on private actors**\n\n- Incentive to comply promptly: aircraft cannot legally be flown beyond the inspection deadline without completing the inspection, and cannot fly if rewiring is required but not completed (Compliance).\n- Maintenance providers stand to gain work from rewiring tasks; operators bear the costs.\n- Small operators may face proportionally higher short-term disruption because of aircraft grounding while rework is done.\n\n(Primary sources: Requirements, Compliance, Applicability, Background and the AD’s reference to FAA AD 2009-08-04 and SB 24-3850.)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard single-issue Airworthiness Directive addressing a specific safety defect (blower motor wiring). The scope remains tightly focused on the original safety concern — preventing cockpit smoke from seized blower motors. There is no evidence of scope creep or expansion beyond this specific technical issue."},"complexity_factors":["Multiple conditional pathways (Requirements 2 and 3 are mutually exclusive branches based on inspection findings)","Cross-reference to US FAA regulatory instruments (FAA AD 2009-08-04, Supplemental Type Certificate SA2271SW, AMOC provisions)","Specific bureaucratic approval requirement (Manager, Special Certification Office, ASW-190, Rotorcraft Directorate, FAA) with mandatory letter content","Nested applicability criteria (specific aircraft models + specific modification certificate + specific service bulletin)","Dual compliance timeframe (600 hours OR 6 months, whichever first)","Note: Despite these factors, the document is relatively short, uses standard aviation terminology, and follows a predictable AD structure"],"plain_english_summary":"This AD requires owners/operators of certain Hawker Beechcraft BAe 125-600A and 700A jets (those modified under FAA STC SA2271SW and covered by SB 24-3850) to inspect cockpit ventilation/avionics blower motor wiring and rework it as specified or using FAA-approved methods.  \n\nInspections are due within 600 flight hours or 6 months; repairs must be completed before next flight to prevent motor seizure, overheating, and smoke/fumes entering the cockpit."},"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-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor","history":"/api/acts/ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor/history","analysis":"/api/acts/ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor/analysis","conflicts":"/api/acts/ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor/conflicts","importantCases":"/api/acts/ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor/important-cases","documents":"/api/acts/ad-hs-125-183-cockpit-ventilation-and-avionics-cooling-system-blower-motor/documents"}}