{"id":"F2006B03653","name":"AD/BEECH 1900/35 - KA-33 Cooling Blower","slug":"ad-beech-1900-35-ka-33-cooling-blower","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43243,"registerId":"commonwealth-F2006B03653-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nBeechcraft 1900 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/BEECH 1900/35 KA-33 Cooling Blower 8/","sectionType":"part","heading":"AD/BEECH 1900/35 KA-33 Cooling Blower 8/2001","content":"# AD/BEECH 1900/35 KA-33 Cooling Blower 8/2001\n\nApplicability: Beech Model 1900D aeroplanes, serial numbers UE-1 through UE-401 inclusive. Requirement: Install an in-line fuse holder, part number (P/N) HHJ-A, in wire J51500E-J039002,\n\nand install a one ampere slow-blow fuse, P/N MDA1, in the fuse holder in accordance with Raytheon Mandatory Service Bulletin SB 34-3268, issued April 2000.\n\nNote: FAA AD 2001-11-03 Amdt 39-12244 refers.\n\nCompliance: Within the next 600 hours time-in-service after the effective date of this Directive or the next six calendar months after the effective date of this Directive, whichever occurs first.\n\nThis Airworthiness Directive becomes effective on 9 August 2001.\n\nBackground: The United States Federal Aviation Administration has received several reports of blower motors failing, seizing, smoking, and producing a burning odour that enters the cabin and passenger compartment. These events are the result of the blower motor having circuit protection of more than one ampere. This level of circuit protection does not prevent the blower motor from smoking and creating a burning odour should it fail or seize.\n\nThis Directive introduces measures intended to protect the blower motor circuit and reduce the possibility of emission of smoke or a burning odour into the cockpit or passenger compartment.\n\n![](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 29 June 2001\n\n![](image.001.png)","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It addresses a specific safety defect in a specific aircraft type with a specific technical fix. There is no evidence of scope creep — the directive does not expand beyond the original problem of blower motor circuit protection."},"complexity_factors":["Very short document (approximately 250 words)","Only 2 defined part numbers (P/N HHJ-A and P/N MDA1)","Single, unambiguous requirement with clear manufacturer reference (Raytheon SB 34-3268)","Simple compliance timeframe with binary trigger (600 hours OR 6 months)","No nested exceptions, conditional logic, or cross-references to other legislation beyond a single note referencing the parallel FAA AD","Narrow applicability (single aircraft model, specific serial number range)"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Beechcraft 1900D serials UE-1 to UE-401 install an in-line fuse holder and 1‑amp slow‑blow fuse per Raytheon Service Bulletin SB 34‑3268. The fix prevents cooling blower motors from seizing, overheating, and producing smoke that can enter the cabin by ensuring proper circuit protection. Compliance: within 600 flight hours or six months of the AD."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD is narrowly focused on mitigating a specific unsafe condition (blower motor smoking/burning odour) on a defined subset of Beech 1900D aeroplanes. It does not expand the legislative scope beyond that original safety purpose: it mandates a specific retrofit (parts and installation) referenced to the manufacturer's service bulletin and sets a short, firm compliance window. The AD thus remains within its original, targeted corrective intent rather than growing into a broader regulatory regime."},"complexity_factors":["Short, single‑action directive (install one inline fuse holder and one 1 A slow‑blow fuse)","Narrow applicability: single aircraft model and a contiguous serial number range (UE-1 through UE-401)","One external technical reference (Raytheon Mandatory Service Bulletin SB 34-3268) governs procedural detail","Two compliance triggers combined with a 'whichever occurs first' rule (600 hours TIS or six calendar months)","Simple parts specification (two part numbers given) and one specific wiring run identified (J51500E-J039002)"],"plain_english_summary":"**What this instrument does (mechanics first)**\n\n- This Airworthiness Directive (AD) requires owners/operators of certain Beechcraft 1900D aeroplanes to install an inline fuse holder (P/N HHJ-A) and a 1 ampere slow‑blow fuse (P/N MDA1) in a specific wiring run (wire J51500E-J039002). The installation must follow Raytheon Mandatory Service Bulletin SB 34-3268 (April 2000).\n- It applies only to Beechcraft Model 1900D aeroplanes with serial numbers UE-1 through UE-401 inclusive (see \"Applicability\").\n- Compliance must be completed within the earlier of: 600 hours time-in-service after the AD becomes effective, or six calendar months after that effective date (see \"Compliance\").\n- The AD became effective 9 August 2001.\n\n**Why the AD was issued (stated purpose)**\n\n- The stated reason (in the \"Background\" section) is that blower motors on these aeroplanes have failed, seized, smoked or produced a burning odour entering the cabin because existing circuit protection was greater than one ampere. The AD's mechanical change (installing a 1 A slow‑blow fuse) is intended to provide circuit protection that reduces the likelihood of smoke or burning odour entering the cockpit/passenger compartment.\n\n**Who it affects and who decides**\n\n- Who it affects: owners and operators of the identified Beechcraft 1900D aeroplanes (serials UE-1 to UE-401). Maintenance organisations and technicians who do the work are also affected because they must follow the Raytheon service bulletin when installing the fuse and holder (Requirement section). Parts suppliers may be affected by demand for the specified parts.\n- Who decides/enforces: the Civil Aviation Safety Authority (CASA) delegate issued the AD under subregulation 39.1(1) of CAR 1998 (see heading and opening paragraph). Compliance enforcement and continued airworthiness oversight are the usual responsibilities of CASA and the operator's nominated maintenance authority.\n\n**Costs, incentives and who pays**\n\n- Direct costs are borne by the aircraft owner/operator: purchase of the inline fuse holder (P/N HHJ-A) and the 1 A slow‑blow fuse (P/N MDA1), labour to perform the installation per the Raytheon service bulletin, and aircraft downtime while work is done (Requirement; Compliance).\n- Maintenance organisations benefit from the required work (labour revenue) but must follow the specified service bulletin instructions.\n\n**Trade-offs, risks and implementation issues**\n\n- Trade-off: lowering circuit protection to 1 A reduces the risk of motor overheating and smoke but may increase the chance of the blower circuit blowing a fuse if the motor draws more than 1 A under some conditions. That would require replacement of the fuse and potentially troubleshooting; operators should assess the operational impact of a blown blower circuit. (This is an inherent electrical trade-off implied by the change from \"more than one ampere\" protection to a 1 A fuse — see Background and Requirement.)\n- Implementation dependence: the AD requires installation \"in accordance with\" Raytheon SB 34-3268, so the exact steps and any illustrations or torque/specification limits are contained in that external service bulletin. That delegates procedural specifics to the manufacturer document (Requirement).\n- Compliance burden: the measure is a single, discrete retrofit per affected aeroplane. Records of compliance must be retained in the aircraft maintenance logbook as per normal regulatory practice.\n- Operational risk: if installation is performed incorrectly or the specified parts are not used, the protective effect may not be achieved; inspectors will look for correct part numbers and adherence to the service bulletin.\n\n**Effects on private choice, competition and markets**\n\n- Minimal market distortion: the AD specifies exact part numbers and a specific service procedure. That channels work to suppliers who hold those parts and to maintenance providers who can perform the service, but it is a limited, one‑time retrofit rather than a repeated regulatory cost.\n- Competition effects are small: the AD does not change aircraft ownership, operations authorisations, or broader market entry rules. It imposes a technical retrofit cost on affected aircraft.\n\n**Testing the official rationale against practical considerations**\n\n- Official rationale: lowering circuit protection to 1 A will prevent blower motors from smoking and producing burning odours if they fail or seize (Background).\n- Practical considerations: the retrofit is a targeted, technically specific measure that directly changes circuit protection. The main implementation costs are parts, labour and downtime. A plausible operational consequence (not asserted in the AD text) is occasional fuse replacement or blower inoperative events if in-service motor currents exceed the new 1 A rating; operators must plan for that possibility.\n\n**Where to find the work instructions and related regulatory reference**\n\n- Required procedural detail: Raytheon Mandatory Service Bulletin SB 34-3268, issued April 2000 (Requirement). The AD also cross-references FAA AD 2001-11-03.\n\n**Bottom line**\n\n- If you operate a Beech 1900D with serial UE-1 through UE-401, you must retrofit the specified fuse holder and 1 A slow‑blow fuse on the indicated wiring run within 600 flight hours or six months (whichever comes first), following Raytheon SB 34-3268. The intended effect is to provide circuit protection to reduce the risk of blower motor smoke or burning odour entering the cabin; costs and operational impacts (parts, labour, possible increased nuisance fuse blows) fall on the aircraft owner/operator (Requirement; Compliance; Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower","history":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower/history","analysis":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower/analysis","conflicts":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower/conflicts","importantCases":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower/important-cases","documents":"/api/acts/ad-beech-1900-35-ka-33-cooling-blower/documents"}}