{"id":"F2006B06413","name":"AD/PZL/4 - Vertical Fin Rear Spar","slug":"ad-pzl-4-vertical-fin-rear-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47765,"registerId":"commonwealth-F2006B06413-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PZL/4 - Vertical Fin Rear Spar","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)  \nPZL M18 Dromader Series Aeroplanes\n\nAD/PZL/4 Vertical Fin Rear Spar 13/95\n\nApplicability: Model M18 aircraft with serial numbers up to and including 1Z013-25.\n\nRequirement: 1. Inspect the vertical fin rear spar part number D33.100.00.0 for buckling and cracks using a light and mirror.\n\n2. If buckling and cracking of the spar are found, replace the spar with a serviceable part.\n\nNote: Transport Canada AD CF-95-09 refers.\n\nCompliance: 1. Within 100 hours time in service after 7 December 1995, and thereafter at intervals not to exceed 12 calendar months.\n\n2. Before further flight.\n\nBackground: There is a possibility of cracking and deformation of the vertical fin rear spar. If not detected, this condition could lead to structural failure of the fin and seriously affect the controllability of the aircraft.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural defect in a specific aircraft type. It has not expanded beyond its original purpose of ensuring tail fin integrity in affected PZL M18 aircraft."},"complexity_factors":["Single, specific aircraft model and limited serial number range","Only 2 straightforward requirements (inspect; replace if damaged)","No defined terms section","Simple compliance timeline (100 hours + 12-month recurring)","No cross-references to other legislation beyond a note about a Canadian equivalent","Single background rationale with clear safety justification"],"plain_english_summary":"This is an **Airworthiness Directive** — 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 certain **PZL M18 Dromader aircraft** (a Polish-made agricultural/aerial work plane) to inspect a critical structural part — the **vertical fin rear spar** (the backbone of the tail fin that helps keep the plane stable).\n\n**Who it affects:**\nAnyone who owns or operates a **PZL M18 model with serial numbers up to 1Z013-25**.\n\n**What must be done:**\n- **Inspect** the rear spar for buckling (bending) and cracks using a light and mirror\n- **If damage is found:** Replace the part immediately before flying again\n\n**When:**\n- First inspection within **100 flight hours** after 7 December 1995\n- Then **every 12 months** thereafter\n- **Immediately** if damage is discovered (before next flight)\n\n**Why it matters:**\nCracks or deformation in this spar could cause the tail fin to fail, making the aircraft uncontrollable and potentially causing a crash. This directive was issued after Canadian authorities identified the same problem."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This directive imposes a new, mandatory inspection and replacement requirement on a defined subset of PZL M18 aircraft (Applicability; Requirement; Compliance). Mechanically, it changes maintenance obligations for affected aircraft by adding an initial inspection within 100 hours after 7 December 1995 and recurring inspections not to exceed 12 calendar months, and by requiring immediate replacement before further flight if defects are found (Requirement 1–2; Compliance)."},"complexity_factors":["Narrow and specific applicability (single model and serial-number range) reduces legal and operational complexity (Applicability).","Clear, simple mandatory actions: visual inspection method and replacement if defects found (Requirement 1–2).","Two-part compliance timing: initial inspection within a specified flight-hours window and recurrent inspections at 12-month calendar intervals introduces mixed time metrics (hours and calendar months) (Compliance).","Implementation details left to operators/maintainers: inspection relies on human visual assessment (light and mirror), which can vary by skill and conditions (Requirement 1).","Operational risk from part availability and required grounding if defects are found (Requirement 2; Compliance).","No enforcement, penalty, or approved repair procedure detailed in the text, leaving procedural discretion to regulators and maintainers (no explicit section)."],"plain_english_summary":"This directive requires owners/operators of certain PZL M18 Dromader aircraft (serials up to 1Z013-25) to inspect the vertical fin rear spar (P/N D33.100.00.0) for buckling or cracks and to ground and replace the spar if defects are found. \n\nInspections begin within 100 flight hours after 7 Dec 1995 and recur at least every 12 months. It matters because undetected spar damage could lead to fin failure and loss of controllability, imposing inspection and replacement costs on operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pzl-4-vertical-fin-rear-spar","history":"/api/acts/ad-pzl-4-vertical-fin-rear-spar/history","analysis":"/api/acts/ad-pzl-4-vertical-fin-rear-spar/analysis","conflicts":"/api/acts/ad-pzl-4-vertical-fin-rear-spar/conflicts","importantCases":"/api/acts/ad-pzl-4-vertical-fin-rear-spar/important-cases","documents":"/api/acts/ad-pzl-4-vertical-fin-rear-spar/documents"}}