{"id":"F2006B09185","name":"AD/DHC-8/3 - Propeller Autofeather System","slug":"ad-dhc-8-3-propeller-autofeather-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52971,"registerId":"commonwealth-F2006B09185-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/3 - Propeller Autofeather System","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\n \n\nAD/DHC-8/3 Propeller Autofeather System 2/89\n\nApplicability: All DHC-8-100 series aeroplanes serial numbers 1 through 113 inclusive. Requirement:               Action in accordance with Boeing Canada de Havilland Division SB 8-61-12\n\nRevision A.\n\n \n\nNote: Transport Canada AD CF-88-12R2 and FAA AD 88-12-51 R1 refer.\n\n \n\nCompliance: Prior to 23 March 1989.\n\n \n\nBackground: Transport Canada have advised that recent incidents have occurred where the propeller has inadvertently unfeathered following activation of the autofeather system. This could result in loss of altitude in critical flight regimes.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-limited safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of mandating a propeller system fix."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (aircraft model and serial number range)","Single compliance action referencing an external service bulletin","No nested conditions, exceptions, or cross-references to other legislation","Straightforward cause-and-effect safety rationale","Minimal regulatory machinery — essentially a 'do this by this date' instruction"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** It requires owners and operators of certain Bombardier DHC-8-100 series aeroplanes (specifically serial numbers 1 through 113) to carry out a specific safety fix. The fix involves following instructions in a manufacturer service bulletin (SB 8-61-12 Revision A) to address a problem with the **propeller autofeather system**.\n\n**The safety problem:** The propeller autofeather system is designed to automatically adjust propeller blades to reduce drag if an engine fails during takeoff. However, Transport Canada (the Canadian aviation regulator) reported incidents where the propeller was **inadvertently unfeathering** (reversing the safety action) after the system activated. This could cause the aircraft to lose altitude dangerously, especially during critical phases of flight like takeoff or landing.\n\n**Who it affects:** Operators of early-model DHC-8-100 aircraft (the first 113 built). These are regional turboprop aircraft commonly used by airlines like QantasLink and others for short-haul flights.\n\n**Why it matters:** This is a **flight-critical safety issue**. An unfeathered propeller on a failed engine creates significant drag, potentially causing the aircraft to lose control or altitude when the pilot needs it most. The directive makes the fix mandatory before 23 March 1989.\n\n**Key compliance point:** The work had to be completed before 23 March 1989, meaning this AD is now historical — it applied to aircraft operations in the late 1980s."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's scope remains as originally framed in the source: it applies only to DHC-8-100 series aeroplanes serial numbers 1–113 and requires action in accordance with Boeing Canada de Havilland SB 8-61-12 Revision A to address incidents of inadvertent propeller unfeathering. There is no text in the provided instrument indicating an expansion or contraction of that applicability or the required remedy beyond the stated serial-number range, the referenced service bulletin, and the compliance date. (Applicability; Requirement; Compliance; Background)"},"complexity_factors":["Narrow applicability limited to DHC-8-100 serial numbers 1–113 (Applicability)","Mandated corrective action is specified by an external service bulletin (Boeing Canada de Havilland SB 8-61-12 Rev A) rather than detailed in the AD itself (Requirement)","Cross-reference to related foreign airworthiness directives (Transport Canada and FAA) that may require consultation (Note)","Fixed compliance deadline requiring scheduling and potential aircraft downtime (Compliance)","Safety-critical subject matter (propeller autofeather system) increases operational and regulatory significance despite simple drafting (Background)"],"plain_english_summary":"This CASA directive requires owners/operators of De Havilland DHC‑8‑100 aeroplanes (serials 1–113) to carry out the work specified in Boeing Canada de Havilland Service Bulletin SB 8‑61‑12 Revision A on the propeller autofeather system. Issued after reports of inadvertent unfeathering that could cause loss of altitude, compliance (at operators’ cost) was mandatory by 23 March 1989 and is enforceable by CASA."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-3-propeller-autofeather-system","history":"/api/acts/ad-dhc-8-3-propeller-autofeather-system/history","analysis":"/api/acts/ad-dhc-8-3-propeller-autofeather-system/analysis","conflicts":"/api/acts/ad-dhc-8-3-propeller-autofeather-system/conflicts","importantCases":"/api/acts/ad-dhc-8-3-propeller-autofeather-system/important-cases","documents":"/api/acts/ad-dhc-8-3-propeller-autofeather-system/documents"}}