{"id":"F2005L03590","name":"AD/EMB-120/33 Amdt 1 - Aileron and Elevator Rotary Variable Inductive Transducer Bellcrank Assemblies","slug":"ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39193,"registerId":"commonwealth-F2005L03590-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Embraer EMB-120 (Brasilia) Series Aeropl","sectionType":"division","heading":"Embraer EMB-120 (Brasilia) Series Aeroplanes","content":"### Embraer EMB-120 (Brasilia) Series Aeroplanes\n\n| AD/EMB-120/33 Amdt 1 | Aileron and Elevator Rotary Variable Inductive Transducer Bellcrank Assemblies | 13/2005 |\n| -------------------- | ------------------------------------------------------------------------------ | ------- |\n\n| Applicability: | All EMB-120( ) models, serial numbers 120004 and 120006 through 120358 inclusive, modified in accordance with any revision of Embraer Service Bulletins (SB) 120-31-0039, 120-31-0040, 120-31-0041 or 120-31-0042.                                                                                                                                                                                                                           |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | If not accomplished in accordance with AD/EMB-120/33, replace rotary variable inductive transducer (RVIT) bellcranks having part number (P/N) 123-82549-007 or 123-82549-009, as applicable, with bellcranks having P/N 145-51146-001 or145-51147-001, respectively, in accordance with Embraer Service Bulletin120-31-0046 Revision 1 dated 27 December 2002 or later revision approved by the Brazilian Centro Técnico Aeroespacial (CTA). |\n|                | Note: DAC (Brazil) AD 2001-07-01R2 and Errata dated 25 October 2005 refer.                                                                                                                                                                                                                                                                                                                                                                   |\n| Compliance:    | Remains unchanged as “Within the next 4000 hours time in service or at the first maintenance action that requires the disassembly of the aileron/elevator RVITs, whichever occurs first, after the effective date of the original issue of this Directive”.                                                                                                                                                                                  |\n|                | This Amendment becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                        |\n| Background:    | The Brazilian Departamento de Aviação Civil (DAC) has received reports of aileron control range being limited due to interference between the aileron RVIT bellcrank and the head of the pin that attaches the RVIT support. The DAC has determined that similar interference may also occur with the elevator RVIT bellcrank limiting the range of elevator control.                                                                        |\n|                | The original issue of this Directive required a one-time modification of both RVIT bellcrank assemblies to ensure the there is no interference which may limit either aileron or elevator travel.                                                                                                                                                                                                                                            |\n|                | This Amendment increases the applicability range but also allows compliance in accordance with futures revisions of the Embraer SB approved by the Brazilian CTA.                                                                                                                                                                                                                                                                            |\n|                | The original issue of this Directive became effective on17 April 2003.                                                                                                                                                                                                                                                                                                                                                                       |\n\n|     | AD/EMB-120/30, which required a one-time inspection of the RVIT bellcrank assemblies, is related to this Directive. |\n| --- | ------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n9 November 2005","sortOrder":0},{"sectionNumber":"AD/EMB-120/33 Amdt 1","sectionType":"part","heading":"AD/EMB-120/33 Amdt 1","content":"## AD/EMB-120/33 Amdt 1","sortOrder":1},{"sectionNumber":"Aileron and Elevator Rotary Variable Ind","sectionType":"part","heading":"Aileron and Elevator Rotary Variable Inductive Transducer Bellcrank Assemblies","content":"## Aileron and Elevator Rotary Variable Inductive Transducer Bellcrank Assemblies","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original safety purpose — preventing control interference in EMB-120 aircraft. While it expands the serial number range of affected aircraft and allows for future-approved service bulletin revisions, this represents a refinement of the original scope rather than mission creep. The core safety issue (RVIT bellcrank interference) and the fundamental remedy (part replacement) remain unchanged from the original 2003 directive."},"complexity_factors":["Highly specific technical scope limited to one aircraft type and specific serial number ranges","Multiple cross-references to external documents (Embraer Service Bulletins, Brazilian aviation authority directives)","Conditional applicability based on prior modifications (SB 120-31-0039 through 0042)","Precise part number identification required for compliance (4 different P/Ns referenced)","Nested compliance timing ('whichever occurs first' condition)","Regulatory dependency on foreign aviation authority approval (Brazilian CTA)"],"plain_english_summary":"This AD mandates replacement of certain RVIT bellcranks on affected Embraer EMB‑120 aircraft to prevent interference that could limit aileron or elevator travel. It applies to serials 120004 and 120006–120358 only if previously modified per specified Embraer service bulletins. Operators must install the improved bellcranks per Embraer SB 120‑31‑0046 (or later approved revisions) within 4,000 flight hours or at the next disassembly of the affected parts. Amendment 1 broadens applicability and accepts future approved SB revisions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment broadened the directive’s scope compared with the original issue in two concrete ways: it increases the range of affected aircraft (extended applicability by serial numbers and modification status) and it permits compliance using later revisions of the Embraer service bulletin provided those revisions are approved by the Brazilian CTA. Mechanically, that keeps the original one‑time replacement requirement but makes more aircraft subject to it and adds flexibility about which later SB revisions are acceptable as compliance methods."},"complexity_factors":["Applicability conditional on a serial-number range (120004 and 120006–120358) and prior modification status to any of four specific Embraer SBs (120-31-0039, -0040, -0041, -0042).","Replacement requirement references two old part numbers (123-82549-007, 123-82549-009) and two new part numbers (145-51146-001, 145-51147-001).","Direct cross-references to a specific service bulletin (Embraer SB 120-31-0046 Rev 1) with allowance for later revisions approved by the Brazilian CTA (adds regulatory discretion/variability).","Compliance timing contains a dual condition: within 4,000 hours time-in-service OR at the first maintenance action requiring RVIT disassembly, whichever occurs first.","Multiple external cross-references: Brazilian DAC/CTA ADs and a related AD/EMB-120/30 (inspection requirement).","Amendment changes scope (expanded applicability and allowance for future SB revisions) rather than changing the core technical fix."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It orders the replacement of specific aileron and elevator rotary variable inductive transducer (RVIT) bellcrank assemblies on certain Embraer EMB-120 (Brasilia) aeroplanes. Specifically, operators must replace bellcranks with part numbers (P/N) 123-82549-007 or 123-82549-009 with the new P/Ns 145-51146-001 or 145-51147-001 respectively, following Embraer Service Bulletin 120-31-0046 Revision 1 (dated 27 Dec 2002) or a later revision that has been approved by the Brazilian Centro Técnico Aeroespacial (CTA). (See the \"Requirement\" section.)\n\n- The compliance timing is unchanged from the original directive: replacement must be done within the next 4,000 flight hours or at the first maintenance action that requires disassembly of the aileron/elevator RVITs, whichever comes first, counted from the effective date of the original directive. (See the \"Compliance\" section.)\n\n- The amendment also expands which aircraft the directive applies to (see \"Applicability\") and permits using later approved revisions of the Embraer service bulletin as an acceptable means of compliance. (See the \"Background\" and \"Requirement\" sections.)\n\n**Who this affects**\n\n- Aircraft owners/operators of Embraer EMB-120 series with serial numbers 120004 and 120006 through 120358 inclusive, but only if those aeroplanes have been modified in accordance with any revision of Embraer Service Bulletins 120-31-0039, 120-31-0040, 120-31-0041 or 120-31-0042. (See \"Applicability\".)\n\n- Maintenance organisations and licensed engineers who will perform the part replacements and record compliance under approved procedures.\n\n- Parts suppliers who provide the replacement bellcranks (P/Ns 145-51146-001 and 145-51147-001).\n\n**Why it matters (safety mechanism and source claim)**\n\n- The Brazilian aviation authority (DAC) received reports that the aileron RVIT bellcrank could interfere with the head of the pin attaching the RVIT support, which could limit aileron travel. They judged a similar interference risk could affect the elevator bellcrank and limit elevator travel. The replacement bellcranks are required to eliminate that interference risk. (See \"Background\".)\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Aircraft owners/operators pay for parts, labour and any downtime required to perform the replacement.\n- The regulator (the Civil Aviation Safety Authority acting under the directive and referencing the DAC/CTA approval) decides the mandatory action and accepts compliance via Embraer service bulletins approved by the CTA.\n- Maintenance organisations must schedule the replacement within the prescribed time window or at the next relevant disassembly, and they must use the specified service bulletin procedure (or a later CTA-approved revision).\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: purchase of replacement bellcranks and installation labour; opportunity cost of aircraft downtime for maintenance.\n- Incentives: operators have an incentive to combine this work with scheduled maintenance (the directive allows compliance at the first maintenance action that disassembles RVITs) to minimise downtime costs.\n- Trade-offs: the directive imposes a one-time compliance cost in exchange for reducing the risk of restricted control travel. There is an implementation dependence on parts availability and on approved service bulletin revisions.\n\n**Implementation risk and compliance burden**\n\n- Administrative burden: operators must check serial-number applicability and modification history (the directive applies only to aircraft modified per specified SBs) and keep records showing compliance with the required SB revision or later CTA-approved revision.\n- Practical risks: supply delays for the specified replacement parts, scheduling difficulties to meet the 4,000-hour window, and ensuring the maintenance action actually disassembles the RVITs (so the allowance for ‘‘first maintenance action that requires the disassembly of the aileron/elevator RVITs’’ is applied correctly).\n\n**Cross-references and related measures**\n\n- The directive cross-references DAC AD 2001-07-01R2 (and Errata) and notes a related Australian AD/EMB-120/30 which required a one-time inspection of the RVIT bellcrank assemblies. These cross-references affect how operators find acceptable procedures and the historical sequence of required actions. (See \"Background\" and notes.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies","history":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies/history","analysis":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies/analysis","conflicts":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies/conflicts","importantCases":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies/important-cases","documents":"/api/acts/ad-emb-120-33-amdt-1-aileron-and-elevator-rotary-variable-inductive-transducer-bellcrank-assemblies/documents"}}