{"id":"F2006B06179","name":"AD/PFP/4 - Fairey Metal Propellers Prop Retaining Nut - Inspection","slug":"ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47028,"registerId":"commonwealth-F2006B06179-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PFP/4 - Fairey Metal Propellers Prop Retaining Nut - Inspection","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 - Fixed Pitch\n\n \n\nAD/PFP/4 Fairey Metal Propellers Prop NK Retaining Nut - Inspection\n\nApplicability: All Fairey metal propellers.\n\n \n\nRequirement: Check the propeller hub retaining nuts for tightness.\n\n \n\nCompliance: Within 5 hours time in service after each installation and there-after at intervals not exceeding 100 hours time in service.\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\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text as supplied does not indicate any change to the AD’s scope from an earlier version. The directive applies to all Fairey metal propellers and prescribes the inspection requirement and inspection intervals as stated (Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow and clear scope: applies to all Fairey metal propellers (Applicability).","Simple, single technical action required (check nut tightness) (Requirement).","Prescriptive and short compliance intervals are explicit (within 5 hours after installation; then every 100 hours) (Compliance).","Lack of procedural detail (no torque values, inspection method, pass/fail criteria, or record-keeping specified) increases implementation ambiguity (Requirement).","No stated exceptions, variations, or administrative processes in the text reduces regulatory complexity but may shift complexity to operator judgement (Compliance).","Potential operational scheduling complexity for operators to fit inspections into service cycles (Compliance)."],"plain_english_summary":"What this instrument does (mechanically)\n\n- This Airworthiness Directive (AD/PFP/4) requires inspections of the propeller hub retaining nuts on all Fairey metal propellers. (Applicability; Requirement)\n- The inspection must be done within 5 hours time in service after each installation of the propeller and then at intervals not exceeding 100 hours time in service. (Compliance)\n\nWho it affects\n\n- Aircraft owners and operators who have Fairey metal propellers fitted to their aircraft. (Applicability)\n- Maintenance organisations and mechanics who carry out propeller installations and inspections. (Requirement)\n\nWhy it matters (official claim and practical implications)\n\n- The AD’s stated requirement is to check the propeller hub retaining nuts for tightness (Requirement). The stated purpose is to ensure the nuts remain tight after installation and during service, which mechanically reduces the risk of nut loosening.\n\nCosts, incentives and trade-offs (tested against the text)\n\n- Who pays: Operators/owners and their maintenance providers bear the direct cost of carrying out the inspections and any corrective work discovered. This follows from the inspection obligation and the compliance intervals in the AD (Requirement; Compliance).\n- Time and downtime: The inspection schedule (within 5 hours after installation and every 100 hours thereafter) creates a recurring maintenance task that consumes labour time and may require aircraft downtime. (Compliance)\n- Incentives: Operators are incentivised to perform inspections and corrective maintenance to avoid in-service nut loosening. There is no financial assistance or offset specified in the AD; compliance is an operational cost to the operator. (Requirement; Compliance)\n- Trade-offs and opportunity cost: Time spent on these inspections displaces other uses of aircraft or maintenance resources. Operators may alter installation timing or maintenance scheduling to manage inspection timing. (Compliance)\n\nImplementation risk, compliance burden and discretion\n\n- The AD specifies what to check (tightness) and when to check it, but it does not specify inspection method, torque values, pass/fail thresholds, record-keeping requirements, or the qualification required of the person doing the check. This absence creates room for variation in how the requirement is executed and may require operators or maintenance organisations to rely on manufacturer guidance or maintenance best practice. (Requirement; Compliance)\n- Because the AD does not prescribe procedural detail, implementation risk includes inconsistent inspection techniques, variable judgments about what constitutes “tightness,” and potential disputes about compliance sufficiency. (Requirement)\n\nEffects on markets and behaviour (market-liberal lens)\n\n- The AD imposes recurring maintenance demand on operators, which benefits maintenance providers who perform inspections and any subsequent repairs. (Requirement; Compliance)\n- The requirement constrains operators’ choices about maintenance timing and creates an ongoing compliance cost; it does not change ownership, pricing, or competition directly, but it does create demand for inspection labour and any replacement parts.\n\nConcentrated benefits and diffuse costs\n\n- Benefits from reduced risk of nut failure are concentrated among individual aircraft and their users (safer operation for those aircraft). The costs of inspections are borne by the operators and are diffuse across all operators of affected propellers. (Applicability; Requirement; Compliance)\n\nSummary statement\n\n- Mechanically, the AD mandates checking the tightness of propeller hub retaining nuts on all Fairey metal propellers, first within 5 hours after installation and then every 100 hours of service. Operators and maintenance providers must perform and pay for these checks. The AD specifies timing but does not specify inspection procedures or documentation, which creates implementation choices and potential variability in how compliance is met. (Applicability; Requirement; Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose airworthiness directive focused specifically on inspecting retaining nuts on Fairey metal propellers. It has not expanded beyond its original safety purpose."},"complexity_factors":["Extremely short document (under 150 words)","No defined terms section","No cross-references to other legislation","Simple, unambiguous requirement: check nuts for tightness","Clear, single compliance timeframe with no exceptions or conditions","No nested logic or subsections"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA). It applies to **all Fairey metal propellers** (a specific brand and type of aircraft propeller).\n\n**What it requires:**\n- Aircraft owners or operators must **check that the propeller hub retaining nuts are tight** — these are the nuts that hold the propeller securely onto the aircraft engine.\n\n**When to do it:**\n- **Within 5 hours of flying time** after the propeller is installed; and\n- **Every 100 hours of flying time** after that.\n\n**Why it matters:**\nLoose retaining nuts could cause the propeller to detach in flight, which would be catastrophic. This rule ensures regular checks to catch any loosening before it becomes dangerous. It's a straightforward mechanical inspection requirement designed to prevent mechanical failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection","history":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection/history","analysis":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection/analysis","conflicts":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection/conflicts","importantCases":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection/important-cases","documents":"/api/acts/ad-pfp-4-fairey-metal-propellers-prop-retaining-nut-inspection/documents"}}