{"id":"F2005L03943","name":"AD/DO 328/19 - Propeller Blade Overheat Protection","slug":"ad-do-328-19-propeller-blade-overheat-protection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39793,"registerId":"commonwealth-F2005L03943-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Dornier 328 Series Aeroplanes","sectionType":"division","heading":"Dornier 328 Series Aeroplanes","content":"### Dornier 328 Series Aeroplanes\n\n| AD/DO 328/19 | Propeller Blade Overheat Protection | 1/2006 |\n| ------------ | ----------------------------------- | ------ |\n\n| Applicability: | Model 328-100 aeroplanes with serial numbers 3005 to 3050 inclusive.                                                                                                                                                                                                                                                                                                                                                                                                              |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. If not previously accomplished, remove from service de-icing system timer part number (P/N) A-5639-2 or 4E2947-2 and replace it with in timer P/N A-5639-3 or 4E2947-3 in accordance with the Accomplishment Instructions of Dornier Service Bulletins SB-328-30-164, dated 30 April 1996.                                                                                                                                                                                     |\n|                | 2. De-icing system timers P/N A-5639-2 or 4E2947-2 may not be installed on any aeroplane as a replacement spare.                                                                                                                                                                                                                                                                                                                                                                  |\n|                | Note: LBA AD 1999-027 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Compliance:    | For Requirement 1 - Within 30 days after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                    |\n|                | For Requirement 2 - As of the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 19 January 2006.                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background:    | The German Luftfahrt-Bundesamt (LBA) has received advice from the aircraft manufacturer that a short circuit in of the propeller or airframe de-ice wiring together with a subsequent failure of de-ice timer/monitor could result in a propeller blade overheat. This overheating may result even if the aircraft de-ice switch is in the “OFF” position.This Directive requires the replacement of de-ice timers and prohibits the use of certain timers as replacement spares. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n29 November 2005","sortOrder":0},{"sectionNumber":"AD/DO 328/19","sectionType":"part","heading":"AD/DO 328/19","content":"## AD/DO 328/19","sortOrder":1},{"sectionNumber":"Propeller Blade Overheat Protection","sectionType":"part","heading":"Propeller Blade Overheat Protection","content":"## Propeller Blade Overheat Protection","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly targeted to a specific safety problem (propeller blade overheat caused by a wiring short combined with a timer/monitor failure) and prescribes a single technical fix (replacement of specified de-ice timers and prohibition of the old units as spares). It remains within the original safety-focused purpose described in the background and does not expand obligations beyond that corrective action. The action is limited to identified serial numbers and does not broaden applicability or add unrelated regulatory requirements."},"complexity_factors":["Narrow applicability: single model (Dornier 328-100) and limited serial number range (3005–3050).","Only two operative requirements (replace specified timers; prohibition on specified spare timers).","Single, short compliance timeline for replacement (30 days) plus immediate prohibition for spares.","Four specific part numbers referenced (A-5639-2, 4E2947-2, A-5639-3, 4E2947-3).","Cross-reference to an external technical document (Dornier Service Bulletin SB-328-30-164) for the accomplishment instructions.","Cross-reference to another regulator’s AD (LBA AD 1999-027) for related context.","Technical subject-matter (electrical/de-ice system) requires maintenance competence to implement, but the directive itself is procedurally simple."],"plain_english_summary":"**What this directive does (mechanically)\n\n- Affects: Dornier 328-100 aeroplanes with serial numbers 3005 through 3050 inclusive.\n\n- Mandatory actions:\n  - Requirement 1: If not already done, remove de-icing system timer unit part number A-5639-2 (or 4E2947-2) and replace it with timer part number A-5639-3 (or 4E2947-3), following the Dornier Service Bulletin SB-328-30-164 (Accomplishment Instructions).\n  - Requirement 2: Do not install timers P/N A-5639-2 or 4E2947-2 as replacement spares on any aeroplane.\n\n- Timing (compliance):\n  - The physical replacement in Requirement 1 must be completed within 30 days after the directive takes effect.\n  - The ban on installing the old timers as spares (Requirement 2) is effective immediately on the directive's date.\n\n- Safety reason given: The manufacturer advised that if de-ice wiring shorts together with a failure of the de-ice timer/monitor, a propeller blade can overheat even when the de-ice switch is OFF. The changed timer is intended to prevent that overheating. The directive also refers to a related German LBA airworthiness directive (LBA AD 1999-027).\n\nWho pays, who decides, and what behaviour changes\n\n- Who pays: The operator or owner of each affected aeroplane must bear the cost of obtaining the approved replacement timer and the labour to fit it (maintenance facility costs, possible aircraft downtime).\n\n- Who decides/implements: The aircraft operator and the maintenance organisation carry out the replacement in accordance with the Dornier service bulletin; the regulator (Civil Aviation Safety Authority delegate) enforces compliance by making the directive mandatory.\n\n- Behaviour changes required:\n  - Replace specified de-ice timers within 30 days (Requirement 1).\n  - Stop using the older timer P/Ns A-5639-2 / 4E2947-2 as spares immediately (Requirement 2).\n\nMechanics and dependencies\n\n- The directive does not itself give step-by-step maintenance procedures; it mandates completion in accordance with Dornier Service Bulletin SB-328-30-164, so compliance depends on following those technical instructions.\n- The directive cross-references a prior LBA AD (1999-027); that is additional regulatory context but the immediate obligations here are the two listed requirements.\n\nOperational consequences, trade-offs and implementation risks\n\n- Immediate maintenance cost and short-term aircraft downtime for affected serial numbers.\n- Dependence on parts availability: if approved replacement timers are scarce, operators may face scheduling delays or higher parts costs.\n- The benefit is reduced risk of propeller blade overheating caused by the described wiring/monitor failure combination; the directive achieves this by prescribing a hardware replacement and prohibiting use of the older unit as a spare.\n\nNotes on legal force and effect\n\n- The directive is mandatory for the specified aeroplanes; the compliance deadlines are binding. Failure to comply would leave the aircraft non-compliant with the airworthiness directive.\n\n(References in the directive: \"Requirement 1\", \"Requirement 2\", the Dornier Service Bulletin SB-328-30-164, and LBA AD 1999-027.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific safety defect in a limited fleet. The scope remains precisely focused on the identified propeller overheat risk and has not expanded beyond this original safety purpose."},"complexity_factors":["Single, specific technical requirement with clear part numbers","Only two compliance actions required (replacement and prohibition)","Narrow applicability: single aircraft model, specific serial number range","No nested exceptions or conditional logic","Only 4 defined part numbers referenced","Clear, fixed compliance dates with no alternative methods stated","Background explanation is straightforward and technical but not legally convoluted"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's aviation regulator (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:**\nThis directive orders owners and operators of certain Dornier 328-100 aeroplanes to replace faulty de-icing system timers. The old timers (part numbers A-5639-2 or 4E2947-2) must be swapped for improved versions (A-5639-3 or 4E2947-3). The old timers are also banned from being used as spare parts.\n\n**Why it matters:**\nThe manufacturer discovered a dangerous fault: if the propeller or airframe de-icing wiring short-circuited while the old timer failed, the propeller blades could overheat — even when the de-icing switch was turned **OFF**. This creates a fire risk or potential damage to the aircraft.\n\n**Who it affects:**\n- Owners and operators of Dornier 328-100 aircraft with serial numbers 3005 through 3050\n- Maintenance organisations servicing these aircraft\n\n**When action was required:**\n- Replacement of existing timers: within 30 days of 19 January 2006\n- Ban on installing old timers as spares: immediate from 19 January 2006\n\n**Key point:** This is a **safety-critical compliance requirement** — not optional guidance. Failure to follow an Airworthiness Directive grounds the aircraft (makes it illegal to fly)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection","history":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection/history","analysis":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection/analysis","conflicts":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection/conflicts","importantCases":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection/important-cases","documents":"/api/acts/ad-do-328-19-propeller-blade-overheat-protection/documents"}}