{"id":"F2006B05075","name":"AD/CESSNA 180/62 - Vertical Fin Rear Spar","slug":"ad-cessna-180-62-vertical-fin-rear-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44985,"registerId":"commonwealth-F2006B05075-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 180/62 - Vertical Fin Rear Spar","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)  Cessna 180, 182 and Wren 460 Series Aeroplanes\n\n \n\nAD/CESSNA 180/62 Vertical Fin Rear Spar 12/80\n\nApplicability: Model 180 with S/Nos. 18052385 to 18053147. Requirement:  Action in accordance with Cessna SIL No. SE80-85. Compliance:               Within 100 hours time in service after 31 December 1980.\n\nBackground: Overseas, cracks have been found in the flanges and web of the spar below the lower rudder hinge.\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":{"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 defined aircraft population. It has not expanded beyond its original purpose of mandating inspection and repair of the vertical fin rear spar."},"complexity_factors":["Single, specific applicability (one model, defined serial number range)","Single requirement referencing external document (Cessna SIL)","Simple compliance deadline (100 hours time in service after fixed date)","No defined terms section","No cross-references to other legislation or regulations","No conditional logic or exceptions","Extremely short (under 150 words of substantive content)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Cessna 180 aircraft to inspect and repair the **vertical fin rear spar** (the structural backbone of the tail fin that holds the rudder). The directive references a specific Cessna Service Information Letter (SIL No. SE80-85) that details what actions must be taken.\n\n**Who it affects:** \n- **Aircraft:** Cessna Model 180 aeroplanes with serial numbers 18052385 to 18053147\n- **People:** Owners, operators, and maintenance engineers responsible for these aircraft\n\n**Why it matters:** Cracks have been discovered in the tail fin structure on similar aircraft overseas. These cracks appear in the flanges (the reinforced edges) and web (the flat central section) of the spar below the lower rudder hinge. If left unchecked, this structural failure could cause the tail fin to break off in flight — a catastrophic safety risk.\n\n**What must be done:**\n- **When:** Within 100 hours of flying time after 31 December 1980\n- **How:** Follow the instructions in Cessna Service Information Letter SE80-85\n\n**The bottom line:** This is a \"fix it or ground it\" order. The aircraft cannot legally fly beyond the compliance deadline without completing this inspection and any necessary repairs."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope remains limited to Model 180 aeroplanes with serial numbers 18052385 to 18053147 and requires action per the manufacturer’s Service Information Letter within the specified 100-hour timeframe. There is no indication in the text that the scope was broadened or narrowed from that specific applicability. (Applicability; Requirement; Compliance)"},"complexity_factors":["Narrow applicability limited to a single model and a tight serial-number range (Applicability).","Single external technical reference: compliance requires following Cessna Service Information Letter SE80-85 rather than multiple regulatory provisions (Requirement).","Short, definite compliance window tied to flight hours after a calendar date (100 hours after 31 December 1980) (Compliance).","Clear stated safety issue (cracks in spar flanges and web below lower rudder hinge) reduces ambiguity about purpose (Background)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Cessna 180s (S/N 18052385–18053147) to carry out the inspection and any repairs specified in Cessna Service Information Letter SE80-85 within 100 hours’ time‑in‑service after 31 December 1980. Issued after discovery of cracks in the vertical‑fin rear spar, it is mandatory under CASA and the compliance costs and downtime fall to the aircraft owners/operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar","history":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar/history","analysis":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar/analysis","conflicts":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar/conflicts","importantCases":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar/important-cases","documents":"/api/acts/ad-cessna-180-62-vertical-fin-rear-spar/documents"}}