{"id":"F2006B11378","name":"AD/MU-2/48 - Rudder Trim Tab","slug":"ad-mu-2-48-rudder-trim-tab","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57279,"registerId":"commonwealth-F2006B11378-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/48 - Rudder Trim Tab","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-2/48 Rudder Trim Tab 4/91 DM\n\nApplicability: Model MU-2B/-10/-15/-20: S/N 008 through 211. Model MU-2B-30:  S/N 502 through 542.\n\nModel MU-2B-36: S/N 501.\n\n \n\nRequirement: Action IAW the technical requirements of Japan CAB AD TCD-3378-90.\n\n \n\nNote: MHI SB 211 refers.\n\n \n\nCompliance: Within 100 hours time in service after 28 February 1991 or prior to 20 May 1991; whichever occurs first.\n\n \n\nBackground:  A field report revealed that the rudder trim tab could interfere with the rudder trailing edge when full right rudder and full left rudder trim are applied at the same time during single engine operation. To preclude future occurrence of this condition, the trim tab leading edge requires modification.\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":4,"scope_assessment":{"changed":false,"description":"The AD enforces the modification described in the background to prevent trim‑tab/rudder interference on the specified serial numbers. It aligns with the stated intent and does not broaden or narrow the affected population or required action beyond that intent."},"complexity_factors":["Safety‑critical aerodynamic control‑surface modification (rudder trim tab leading edge) requiring technical work by maintenance personnel.","Applicability limited to specific MU-2 models and serial number ranges, requiring operators to check serial‑number lists.","Cross‑referencing to external documents (Japan CAB AD TCD-3378-90 and MHI SB 211) for technical instructions increases compliance steps.","Short compliance deadline (100 flight hours after 28 Feb 1991 or before 20 May 1991) creates scheduling and logistical pressure for operators.","Background identifies a specific operational condition (full opposite rudder and trim during single‑engine operation), making the required fix narrowly targeted but safety‑critical."],"plain_english_summary":"Requires modifying the rudder trim tab leading edge on specified Mitsubishi MU-2 aeroplanes to prevent the trim tab contacting the rudder when full opposite rudder and trim are applied during single‑engine operation. It references Japan CAB AD TCD‑3378‑90 (MHI SB 211).\n\nOperators of listed serial numbers must complete the modification within 100 flight hours after 28 Feb 1991 or by 20 May 1991, whichever is earlier. The rule mandates a physical control‑surface change and imposes a short compliance window."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical interference issue in specific aircraft models. It has not expanded beyond its original purpose of mandating a rudder trim tab modification."},"complexity_factors":["Very short document (approximately 250 words)","Only 3 defined applicability categories (specific aircraft models and serial numbers)","Single technical requirement referencing external standard (Japan CAB AD TCD-3378-90)","Simple compliance deadline structure (alternative dates, whichever is earlier)","No nested exceptions or conditional logic","No cross-references to other Australian legislation beyond Civil Aviation Regulations 1998 Part 39","Straightforward background explanation with clear safety rationale"],"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) for specific Mitsubishi MU-2 aircraft.\n\n**What it does:** It requires owners and operators of certain Mitsubishi MU-2 aeroplanes to modify the rudder trim tab (a small adjustable surface on the tail that helps keep the plane flying straight). The modification prevents the trim tab from hitting the main rudder when specific control inputs are used together during single-engine operation.\n\n**Who it affects:** Owners and operators of specific Mitsubishi MU-2 models with serial numbers:\n- MU-2B, -10, -15, -20: serial numbers 008 through 211\n- MU-2B-30: serial numbers 502 through 542  \n- MU-2B-36: serial number 501\n\n**Why it matters:** A field report found that applying full right rudder while also using full left rudder trim during single-engine flight could cause the trim tab to physically interfere with the rudder trailing edge. This could damage flight controls or cause loss of control. The directive mandates a fix to prevent this dangerous condition.\n\n**What must be done:** The aircraft must be modified according to Japanese aviation authority technical requirements (Japan CAB AD TCD-3378-90), with reference to Mitsubishi Heavy Industries Service Bulletin 211.\n\n**When:** Within 100 flight hours after 28 February 1991, or before 20 May 1991 — whichever comes first."}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-48-rudder-trim-tab","history":"/api/acts/ad-mu-2-48-rudder-trim-tab/history","analysis":"/api/acts/ad-mu-2-48-rudder-trim-tab/analysis","conflicts":"/api/acts/ad-mu-2-48-rudder-trim-tab/conflicts","importantCases":"/api/acts/ad-mu-2-48-rudder-trim-tab/important-cases","documents":"/api/acts/ad-mu-2-48-rudder-trim-tab/documents"}}