{"id":"F2006B06142","name":"AD/PC-6/38 - Horizontal Stabiliser Inspection","slug":"ad-pc-6-38-horizontal-stabiliser-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46932,"registerId":"commonwealth-F2006B06142-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/38 - Horizontal Stabiliser Inspection","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPilatus Porter PC-6 Series Aeroplanes\n\nAD/PC-6/38 Horizontal Stabiliser Inspection 7/93\n\nApplicability: All Pilatus Porter PC-6 series aircraft. Requirement: Retire the horizontal stabiliser; or\n\nModify the horizontal stabiliser and inspect for cracks in accordance with a scheme approved by the Authority.\n\nNote: Aeronautical Designs Australia Pty Ltd EO-934 is an approved scheme for the purpose of this Directive.\n\nCompliance: Retire before 10000 hours component time in service; or\n\nModify and inspect before 10000 hours component time in service. Re-inspect at intervals not exceeding 100 hours.\n\nBackground: The Pilatus Porter horizontal stabiliser has a history of fatigue cracking in service.\n\nInspection access to some cracking sites is very restricted.\n\nThis AD gives two options: retire before cracks are likely to start; or improve access and inspect.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive’s scope aligns with its stated background: it targets fatigue cracking of the Pilatus Porter horizontal stabiliser. It prescribes two compliance mechanisms (retirement before 10,000 hours, or modification plus recurring inspections) and does not expand or narrow the addressed hazard beyond that purpose (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Two alternative compliance paths (retire component vs modify-and-inspect) require operators to choose between a one-off replacement cost and ongoing inspection costs (Requirement; Compliance).","Fixed retirement/modification deadline tied to component time in service (before 10,000 hours) creates a clear compliance trigger that must be tracked (Compliance).","Short recurring inspection interval (100 hours) increases maintenance scheduling and operational planning demands (Compliance).","Requirement that inspections follow a scheme approved by the Authority adds a regulatory-approval step and constrains acceptable technical methods (Requirement; Note).","Physical constraint: certain crack locations are difficult to access for inspection, increasing implementation and detection risk (Background)."],"plain_english_summary":"What this rule does\n\n- This Airworthiness Directive applies to all Pilatus Porter PC-6 series aeroplanes (Applicability).\n- It requires owners/operators to either: 1) permanently remove (retire) the horizontal stabiliser before it reaches 10,000 hours of component time in service; or 2) modify the stabiliser to improve inspection access and then carry out regular inspections for cracking under a scheme approved by the Civil Aviation Authority (Requirement; Compliance; Note).\n- If the modification-and-inspect option is chosen, inspections must be repeated at intervals not exceeding 100 hours (Compliance).\n\nWho it affects\n\n- Aircraft owners/operators and maintenance organisations responsible for Pilatus Porter PC-6 series aeroplanes (Applicability).\n- Organisations performing the modification and inspections will carry out work under an approved inspection scheme (Requirement; Note).\n\nWhy it matters (official purpose and practical implications)\n\n- The Directive is issued because the Pilatus Porter horizontal stabiliser has a recorded history of fatigue cracking in service and some crack locations are difficult to access for inspection (Background).\n- The Directive’s stated purpose is to reduce the risk of undetected fatigue cracking by either removing the component before cracks typically start, or by improving access and instituting frequent inspections (Background; Requirement).\n\nCosts, incentives and trade-offs (practical mechanics)\n\n- Who pays: owners/operators must bear the cost of retiring and replacing the stabiliser, or of modifying it and performing recurring inspections (Requirement; Compliance).\n- Choice and incentives: operators can choose a single up-front cost (retire component) or an ongoing-cost approach (modify once, then inspect every 100 hours). This creates a clear trade-off between capital replacement and recurring maintenance expense (Requirement; Compliance).\n- Compliance burden: the modify-and-inspect path requires adherence to an Authority-approved inspection scheme; maintenance organisations need procedures and access to perform inspections at the prescribed 100-hour intervals (Note; Compliance).\n- Implementation risk: the Directive notes that some crack sites are hard to access, which raises the chance inspections might miss cracking unless access is improved by modification or inspections are carefully executed (Background).\n- Decision authority and discretion: the Directive requires an inspection scheme approved by the Authority; the Authority therefore decides which modification/inspection schemes meet the directive’s requirements (Requirement; Note).\n\nOperational effects and detectable consequences\n\n- Behavioural change: operators will either remove the part from service sooner than they might otherwise have done, or will invest in modification and increased inspection frequency (Requirement; Compliance).\n- Monitoring and administration: the Authority-approved scheme governs inspection methods and intervals; noncompliance exposes operators to regulatory enforcement (Requirement; Note).\n\nSource citations\n\n- Applicability, Requirement, Compliance and Background text are taken directly from the AD/PC-6/38 directive provided."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standalone Airworthiness Directive with a narrow, specific purpose: addressing fatigue cracking in one aircraft component. It has not expanded beyond its original safety intent."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined compliance paths (retire or modify+inspect)","Single cross-reference to external approved scheme (EO-934)","No nested exceptions or conditional logic","Clear, unambiguous time-based trigger (10,000 hours component time)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of **Pilatus Porter PC-6 series aircraft** to take action on the horizontal stabiliser (the small wing at the tail that keeps the plane level). Because this part has a known history of metal fatigue and cracking in hard-to-reach places, operators must choose one of two options:\n\n- **Option 1:** Permanently remove and retire (stop using) the horizontal stabiliser before it reaches 10,000 hours of flight time; or\n- **Option 2:** Modify the stabiliser to improve crack detection, then inspect it for cracks using an approved scheme (specifically, one from Aeronautical Designs Australia called EO-934) before 10,000 hours, with follow-up inspections every 100 hours thereafter.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains Pilatus Porter PC-6 aircraft in Australia — including charter companies, private owners, and maintenance organisations.\n\n**Why it matters:**\nFatigue cracks in a stabiliser can cause loss of aircraft control. This directive prevents accidents by forcing proactive replacement or enhanced monitoring of a known weak point before it fails."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection","history":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection/history","analysis":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection/analysis","conflicts":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection/conflicts","importantCases":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection/important-cases","documents":"/api/acts/ad-pc-6-38-horizontal-stabiliser-inspection/documents"}}