{"id":"F2006B06314","name":"AD/PR/16 Amdt 1 - Inspection of Hub Driving Centres for Incorrect Machining During Modification","slug":"ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47442,"registerId":"commonwealth-F2006B06314-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/16 Amdt 1 - Inspection of Hub Driving Centres for Incorrect Machining During Modification","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Propellers - Variable Pitch - Dowty Rotol\n\n \n\nAD/PR/16\n\nAmdt 1\n\n\nInspection of Hub Driving Centres for NK Incorrect Machining During Modification\n\n \n\nApplicability: All model (c) R175/4-30-4/13E, (c) R193/4-30-4/50 and /61. (c) R257/4-30-4/60. (Fokker F27). (c) R184/4-30-4 /50. (Gulfstream). (c) R186/4-30-4/16 or 16/1. (Argosy 100 and 200). (c) R212/4-30-4/22/1 (Argosy 222) incorporating Mod. No. (c) VP 2486; or (c) VP 2381.\n\n \n\nDocument: 1. Dowty Rotol SB No. 61-858, Rev. 1, or as applicable; or\n\n \n\n2. Dowty Rotol SB No. 61-857, Rev. 1. Compliance: As detailed in the requirement document.\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":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The instrument is labelled “Amdt 1”, which indicates it amends a prior airworthiness directive. The extract supplied defines applicability (specific propeller models and modification numbers), references two specific Dowty Rotol service bulletins for procedure, and states that compliance is “as detailed in the requirement document.” However, the extract does not include the original AD text or a mark-up of what was changed. Therefore, while the label and the presence of detailed applicability and document references show this is an amendment, the precise nature and extent of any change from the original AD cannot be determined from the supplied text alone."},"complexity_factors":["Technical specificity of affected items: multiple detailed propeller model references and linked aircraft types in the Applicability clause.","References to external documents with precise revision numbers (Dowty Rotol SB No. 61-858 Rev. 1 and SB No. 61-857 Rev. 1) which implement the technical procedure rather than the AD text itself.","Ambiguity in this extract about timing, intervals, and corrective-action criteria because the AD delegates those details to the referenced service bulletins (“Compliance: As detailed in the requirement document.”).","Requirement to check modification history (Mod. No. VP 2486; VP 2381) to determine applicability, which increases administrative work for operators.","Regulatory placement: appears as an amendment (“Amdt 1”) to an existing AD, implying a cross-reference to prior material not included in the extract.","Fragmentary presentation and formatting of the supplied text (limited contextual detail and missing full-text clauses) increases interpretive effort."],"plain_english_summary":"This airworthiness directive (labelled “AD/PR/16 Amdt 1”) requires inspections of certain Dowty Rotol variable-pitch propeller hub driving centres to check for incorrect machining that may have occurred during a modification. It applies to a defined list of propeller model references and to propellers installed on specified aircraft types and incorporating specific modification numbers (see the line beginning “Applicability: All model …” in the source).\n\nMechanically, the AD does three things: it identifies which propellers are covered (the applicability clause); it directs operators and maintenance organisations to follow specific Dowty Rotol service bulletins (Dowty Rotol SB No. 61-858, Rev. 1, or SB No. 61-857, Rev. 1 — see the “Document:” lines); and it requires compliance in the manner set out in those requirement documents (“Compliance: As detailed in the requirement document.”).\n\nWho it affects and who pays\n- Aircraft owners/operators and the maintenance organisations that service these propellers are directly affected (cited from “Applicability: …”).\n- Those operators or maintainers bear the direct costs of inspections, any required corrective work, and any associated aircraft downtime because the AD is an operational requirement to follow the identified service bulletins (cited from “Document: …” and “Compliance: …”).\n\nPractical effects on behaviour and incentives\n- Operators must locate affected propellers (by model and modification number) and schedule inspections per the cited Dowty Rotol SB(s) (source: “Applicability: …” and “Document: …”).\n- Maintenance organisations must carry out the inspections and any repairs required by the service bulletin, creating a compliance burden in the form of labour, parts, and logistical coordination (source: “Document: …” and “Compliance: …”).\n- Because the AD points to an external requirement document rather than prescribing detailed procedures within the AD itself, responsibility for the precise inspection steps and compliance timing rests with the referenced service bulletins (source: “Document: …” and “Compliance: …”).\n\nTrade-offs, risks and implementation points\n- The AD delegates technical detail to manufacturer service bulletins. That reduces duplication in the AD text but creates dependency on those external documents for inspectors and operators (source: “Document: …”).\n- The extract does not specify inspection intervals, corrective-action criteria, or compliance deadlines; it refers users to the requirement document for those specifics, which means implementers must obtain and follow the referenced service bulletin to know the full obligations (source: “Compliance: As detailed in the requirement document.”).\n- The AD identifies the affected items precisely by model and by modification numbers (e.g. “incorporating Mod. No. …VP 2486; or … VP 2381”), so the work of determining applicability can require checking modification records for each propeller/airframe (source: “Applicability: …”).\n\nAuthority and enforcement\n- This directive is published as part of the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives (header: “COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY / SCHEDULE OF AIRWORTHINESS DIRECTIVES”). Enforcement and compliance oversight therefore sit with the relevant aviation safety regulator under the cited regulatory framework.\n\nIn short: the AD identifies specific Dowty Rotol propellers and modifications, requires inspections for incorrect machining of hub driving centres, and instructs operators to follow particular Dowty Rotol service bulletins for the detailed steps. The immediate costs and operational effects fall on aircraft operators and maintenance organisations, who must obtain the referenced service bulletins and carry out the inspections and any corrective work as required."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a narrow, specific safety purpose. It has not expanded beyond its original intent of addressing a known manufacturing/modification defect in specific propeller hubs."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined document references (the Service Bulletins)","Simple conditional logic: applies only to specific propeller models with specific modification numbers","No nested exceptions or cross-references to other legislation","Single compliance requirement: follow the referenced service bulletin","Straightforward applicability section listing specific aircraft and propeller models"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires aircraft owners and operators to inspect or fix specific equipment.\n\n**What it does:** It orders inspections of **propeller hubs** (the central part that connects the propeller blades to the engine) on certain Dowty Rotol variable-pitch propellers. Specifically, it targets hubs that were modified using two particular modification procedures (Mod. No. VP 2486 or VP 2381). The concern is **incorrect machining** (improper cutting or shaping of metal parts) that may have occurred during those modifications.\n\n**Who it affects:** Operators of aircraft using these specific Dowty Rotol propeller models, including:\n- **Fokker F27** aircraft\n- **Gulfstream** aircraft  \n- **Argosy 100, 200, and 222** aircraft\n\n**Why it matters:** Incorrect machining in a propeller hub could lead to **catastrophic failure** of the propeller during flight. This directive ensures potentially defective hubs are identified and corrected before they cause accidents.\n\n**What must be done:** Aircraft operators must follow the detailed inspection procedures in one of two Dowty Rotol Service Bulletins (SB No. 61-858 Rev. 1 or SB No. 61-857 Rev. 1) to check for the machining defects."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification","history":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification/history","analysis":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification/analysis","conflicts":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification/conflicts","importantCases":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification/important-cases","documents":"/api/acts/ad-pr-16-amdt-1-inspection-of-hub-driving-centres-for-incorrect-machining-during-modification/documents"}}