{"id":"F2006B11242","name":"AD/M20/38 - Fuselage Tubular Structure - Modification","slug":"ad-m20-38-fuselage-tubular-structure-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56962,"registerId":"commonwealth-F2006B11242-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/M20/38 - Fuselage Tubular Structure - 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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Mooney M20 Series Aeroplanes\n\n \n\nAD/M20/38 Fuselage Tubular Structure - Modification 2/80\n\nApplicability: All model M20K with S/Nos. 25-0001 to 25-0247. Document:  Mooney SB No. M20-220.\n\nCompliance: Before 1 July 1980.\n\n \n\nBackground: The manufacturer advises of the possibility of the lower fuselage longeron buckling under severe positive gust conditions.\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 directive as provided applies to a defined set of M20K serial numbers and requires a modification per Mooney SB No. M20-220 before a fixed date. Nothing in the supplied text indicates a change in scope from the directive's stated applicability or requirements."},"complexity_factors":["Narrow, specific applicability to a single model and limited serial-number range (Applicability).","Single required action (a modification) referenced to a single manufacturer's service bulletin (Document).","Fixed compliance deadline rather than phased or conditional measures (Compliance).","Lack of technical detail and cost information in the AD text — operators must consult the referenced service bulletin for method and scope (Document).","Regulatory authority and enforcement implied by Part 39 - 105 header, but no alternative compliance or exemption language included in the provided text (header; Compliance)."],"plain_english_summary":"This AD mandates a structural modification (per Mooney Service Bulletin No. M20-220) to certain Mooney M20K aeroplanes (serials 25‑0001 to 25‑0247) to mitigate a risk that the lower fuselage longeron could buckle under severe positive gusts. Owners/operators must arrange and pay for the one‑time modification, completed before 1 July 1980, or leave the aircraft unmodified against the stated safety concern."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in 1980 (as indicated by '2/80' in the reference number). It addresses a specific structural defect in a limited production run of aircraft. There is no indication of scope creep; it remains precisely targeted at the identified safety issue."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 4 defined elements: applicability (specific serial numbers), document reference, compliance deadline, and background","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998, Part 39)","Single unconditional requirement with clear deadline","No exceptions, exemptions, or conditional logic","Technical content limited to one specific aircraft model and one specific structural modification"],"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 Mooney M20K aeroplanes to modify the fuselage tubular structure before 1 July 1980.\n\n**Who it affects:** \n- **Aircraft owners/operators** of Mooney M20K model aeroplanes with serial numbers 25-0001 through 25-0247 (247 aircraft total).\n\n**Why it matters:** \n- The manufacturer (Mooney) identified a safety risk: the **lower fuselage longeron** (a structural tube running along the bottom of the aircraft body) could **buckle** (bend or collapse) under severe positive gust conditions (sudden strong upward air currents).\n- This structural failure could compromise the aircraft's integrity in flight.\n- **Compliance is mandatory** — the modification must be completed by the deadline using the manufacturer's Service Bulletin M20-220 as the technical reference.\n\n**Key takeaway:** If you own one of these specific Mooney aircraft, you must have this structural reinforcement done by the deadline to keep flying legally and safely."}},"importantCases":[],"_links":{"self":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification","history":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification/history","analysis":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification/analysis","conflicts":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification/conflicts","importantCases":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification/important-cases","documents":"/api/acts/ad-m20-38-fuselage-tubular-structure-modification/documents"}}