{"id":"F2006B11394","name":"AD/MU-2/64 - Elevator Trim Indication","slug":"ad-mu-2-64-elevator-trim-indication","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57295,"registerId":"commonwealth-F2006B11394-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/64 - Elevator Trim Indication","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)  \nMitsubishi MU-2 Series Aeroplanes\n\nAD/MU-2/64 Elevator Trim Indication 12/98\n\nApplicability: Model MU-2B-10, \\-15, \\-20, \\-25 and \\-26 aeroplanes with serial numbers (S/N) 008\n\nthrough 347 (except S/N 313 and 321); and model MU-2B-30, \\-35 and \\-36 aeroplanes\n\nwith S/N 501 through 696 (except S/N 652 and 661).\n\nRequirement: Modify the elevator trim indicator scale dial in accordance with Mitsubishi Heavy Industries Service Bulletin No 228 dated 13 July 1998.\n\nNote: JCAB TCD-3740A-98 refers.\n\nCompliance: Within 100 hours time in service from the effective date of this directive.\n\nThis Airworthiness Directive becomes effective on 5 November 1998.\n\nBackground: AD/MU-2/52, issued in 1993, mandated the modification of the autopilot to reduce nose-down trim range. This directive requires the modification of the elevator trim indicator scale to be consistent with the available range of the elevator trim.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"This directive narrows the corrective action to a specific, bounded change: modifying the elevator trim indicator scale dial on identified MU-2 aeroplanes so the indicator matches the actual elevator trim range. The Background links this requirement to an earlier directive (AD/MU-2/52) that altered autopilot trim range; the current instrument does not broaden that earlier directive’s mandate but imposes an additional, specific equipment modification to align the indicator with the changed trim range. (Background; Requirement; Applicability)"},"complexity_factors":["Narrow applicability defined by specific models and serial-number ranges (Applicability)","Action depends on following an external manufacturer Service Bulletin (Requirement)","Short, fixed compliance window (100 hours TIS) tied to an effective date (Compliance)","Technical nature of the work requires qualified maintenance resources and causes aircraft downtime (Requirement)","Cross-reference to an earlier AD (AD/MU-2/52) and to a foreign authority document (JCAB TCD-3740A-98) creates a small chain of dependencies (Background; Note)"],"plain_english_summary":"What this directive changes, mechanically\n\n- It requires a physical change to the elevator trim indicator scale dial on specified Mitsubishi MU-2 aeroplanes. The change must be done exactly as set out in Mitsubishi Heavy Industries Service Bulletin No. 228 (dated 13 July 1998). (Requirement)\n\nWho is affected\n\n- Owners/operators of Mitsubishi MU-2 aeroplanes of the listed models and serial numbers in the Applicability section must comply. The directive lists specific MU-2B variants and a range of serial numbers, with a few serial numbers excluded. (Applicability)\n\nWhen it must be done\n\n- The modification must be completed within 100 hours time in service from the directive’s effective date. The directive became effective on 5 November 1998. (Compliance)\n\nWhy the change is required (official rationale)\n\n- The directive says its purpose is to make the elevator trim indicator scale consistent with the available elevator trim range. It links this requirement to an earlier directive (AD/MU-2/52, 1993) that mandated a change to the autopilot to reduce nose-down trim range; the current action aligns the indicator with that changed trim range. (Background)\n\nPractical consequences, incentives and costs\n\n- Who pays: Owners/operators of affected aeroplanes bear the cost of carrying out the modification, because the directive makes the modification mandatory for applicable aircraft. (Applicability; Requirement)\n\n- What they must do: Have the elevator trim indicator scale dial modified in accordance with Mitsubishi Service Bulletin No. 228. The Service Bulletin is the technical instruction that must be followed. (Requirement)\n\n- Compliance burden and implementation risk: The work is technical and will require access to the aircraft and a person or organisation capable of performing the modification per the manufacturer’s service bulletin. That implies labour, possible parts, and aircraft downtime until the work is complete. The directive prescribes the outcome and references the manufacturer’s instructions; correct implementation depends on following that bulletin. (Requirement)\n\n- Regulatory prescription and discretion: The directive is prescriptive (it mandates the modification and ties compliance to the manufacturer’s service bulletin). It leaves little regulatory discretion about whether to do the work, but it does not in the text limit which maintenance provider may perform the task. (Requirement)\n\n- Effects on private enterprise and markets: The directive imposes a regulatory compliance cost on affected aircraft operators. Maintenance providers capable of carrying out the manufacturer’s procedure are those who can capture the work; the directive neither prescribes a supplier nor directly alters ownership or operational rights of operators beyond the compliance obligation. The modification does not itself change aircraft ownership, but it constrains operators’ choice to retain the existing indicator scale until the mandated change is made. (Requirement; Applicability)\n\n- Interaction with prior regulation: This directive follows AD/MU-2/52 (1993) and, according to the text, exists to align the indicator with the trim range established by that earlier autopilot modification. The linkage means this action is corrective/alignment in relation to a previous mandated change. (Background)\n\nOther notes from the instrument text\n\n- The directive references JCAB TCD-3740A-98. The text does not specify additional operational measures beyond the modification or any post-modification approvals or inspections in this document. (Note)\n\nSource citations: Applicability; Requirement; Compliance; Background; Note."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — a targeted safety modification for a specific aircraft type. It references a 1993 directive but does not expand beyond the original purpose of ensuring cockpit instrumentation accurately reflects aircraft capabilities."},"complexity_factors":["Single, specific technical requirement (modify one dial)","Limited applicability — only 6 model variants with specific serial number ranges","No nested exceptions or conditional logic; straightforward compliance deadline","Short document (under 200 words)","Only one defined reference (Service Bulletin No 228)","No cross-referencing to other legislation sections beyond the background note"],"plain_english_summary":"This is a **safety order for specific Mitsubishi aeroplanes** used in Australia.\n\n**What it does:**\nTells owners of certain MU-2 model planes to change the **elevator trim indicator** — that's the dial in the cockpit showing how much the plane's tail is angled up or down. The dial's markings need updating to match changes made to the autopilot system years earlier.\n\n**Who it affects:**\nOwners and operators of specific Mitsubishi MU-2B aeroplanes built between certain serial numbers (roughly mid-1960s to late 1970s production). Not all MU-2 planes — only those listed by model and serial number.\n\n**Why it matters:**\nBack in 1993, regulators limited how far the autopilot could push the nose down (a safety fix). But the cockpit dial still showed the old, wider range. This creates a dangerous mismatch — pilots might think they have more \"nose-down\" trim available than actually exists. This order fixes the dial so what pilots see matches what the plane can actually do.\n\n**The deadline:**\nPlanes must be fixed within **100 hours of flying time** after 5 November 1998."}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-64-elevator-trim-indication","history":"/api/acts/ad-mu-2-64-elevator-trim-indication/history","analysis":"/api/acts/ad-mu-2-64-elevator-trim-indication/analysis","conflicts":"/api/acts/ad-mu-2-64-elevator-trim-indication/conflicts","importantCases":"/api/acts/ad-mu-2-64-elevator-trim-indication/important-cases","documents":"/api/acts/ad-mu-2-64-elevator-trim-indication/documents"}}