{"id":"F2006B11377","name":"AD/MU-2/47 - Elevator and Rudder Trim Tab Spar","slug":"ad-mu-2-47-elevator-and-rudder-trim-tab-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57278,"registerId":"commonwealth-F2006B11377-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/47 - Elevator and Rudder Trim Tab 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)  Mitsubishi MU-2 Series Aeroplanes\n\n \n\nAD/MU-2/47 Elevator and Rudder Trim Tab Spar 11/90\n\nApplicability: All models as detailed in the Requirement documents. Requirement:  As applicable by serial number, action in accordance with\n\n1. Mitsubishi Service Bulletin MU-2 No 207, dated 20 May 1988, or\n\n\n \n\n2.    Mitsubishi Service Bulletin MU-2 No 068/27-009, dated 12 December 1988.\n\n \n\nCompliance: Within 100 hours time in service after 1 November 1990 and thereafter at intervals not to exceed 300 hours time in service.\n\n \n\nBackground: Two 8.2 inch cracks have recently been reported emanating from the spar radius, which caused separation of the rudder trim tab skin, and subsequent inflight oscillation of the rudder.\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 mechanical defect. It has not expanded beyond its original purpose of mandating inspections for spar cracks in MU-2 aircraft."},"complexity_factors":["Single, specific mechanical issue (trim tab spar cracks)","Only 2 technical reference documents required","Simple compliance timeline (100 hours initial, 300 hours recurring)","No defined terms section","No cross-references to other legislation","Straightforward applicability (all MU-2 models by serial number)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **Mitsubishi MU-2 series aeroplanes** to inspect the **elevator and rudder trim tab spars** (structural metal bars inside the aircraft's tail control surfaces) for dangerous cracks.\n\n**Why it matters:**\nTwo serious cracks (8.2 inches long) were found coming from the spar radius (the curved corner where the spar meets other parts). These cracks caused a rudder trim tab skin to separate in flight, making the rudder shake uncontrollably — a serious flight safety hazard.\n\n**Who must act:**\nAll MU-2 aircraft owners/operators, following specific instructions in two Mitsubishi service bulletins (official repair notices).\n\n**When:**\n- First inspection: within 100 flight hours after 1 November 1990\n- Repeat inspections: every 300 flight hours after that"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument sets a corrective inspection/repair requirement for MU-2 elevator and rudder trim tab spars per specified service bulletins and fixed compliance intervals. The text shows no alteration of scope from that corrective intent: applicability, required documents, and compliance timing are stated within the AD."},"complexity_factors":["Reference to external technical documents (Mitsubishi Service Bulletin MU-2 No 207; MU-2 No 068/27-009) — specific remedial steps are located outside the AD text.","Applicability tied to serial number variation ('as applicable by serial number') creates per-aircraft scope determination.","Fixed but date-relative compliance timing (within 100 hours after 1 Nov 1990, then at intervals not to exceed 300 hours) requires operators to calculate service-hour scheduling.","Technical inspection/repair work on primary control trim spar requires qualified maintenance action and parts, imposing operational and cost burdens on operators.","Regulatory embedding under Civil Aviation Regulations Part 39 / CASA Schedule of Airworthiness Directives — enforces mandatory compliance rather than advisory guidance.","Safety consequence motivating the AD is concrete (reported 8.2 inch cracks, skin separation, inflight rudder oscillation) but the AD does not itself describe repair details — dependence on service bulletins."],"plain_english_summary":"This airworthiness directive requires operators of Mitsubishi MU-2 series aeroplanes (as listed by serial number) to inspect and, if necessary, repair the elevator and rudder trim tab spar in accordance with Mitsubishi Service Bulletins MU‑2 No 207 or No 068/27‑009. The first action must be done within 100 hours time-in-service after 1 November 1990 and repeated at intervals not exceeding 300 hours. It was issued after reports of cracks that caused rudder trim tab skin separation and inflight rudder oscillation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar","history":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar/history","analysis":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar/analysis","conflicts":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar/conflicts","importantCases":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar/important-cases","documents":"/api/acts/ad-mu-2-47-elevator-and-rudder-trim-tab-spar/documents"}}