{"id":"F2009L00513","name":"AD/EMB-145/22 - Landing Gear Electronic Unit","slug":"ad-emb-145-22-landing-gear-electronic-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":77171,"registerId":"commonwealth-F2009L00513-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Embraer EMB-135 and EMB-145 Series Aerop","sectionType":"division","heading":"Embraer EMB-135 and EMB-145 Series Aeroplanes","content":"### Embraer EMB-135 and EMB-145 Series Aeroplanes\n\n| AD/EMB-145/22 | Landing Gear Electronic Unit | 3/2009 |\n| ------------- | ---------------------------- | ------ |\n\n| Applicability: | EMB-135 and EMB-145 series aeroplanes equipped with Landing Gear Electronic Unit (LGEU) part number (P/N) 355-022-002.                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. Replace any LGEU P/N 355-022-002 with serial number (S/N) from 1000 to 1999 with LGEU P/N 355-022-003, according to the detailed instructions and procedures described in the Embraer Service Bulletins (SB) 145-32-0120 original issue or 145LEG-32-0032 original issue, as applicable, or later revisions approved by the Brazilian Agência Nacional de Aviação Civil (ANAC).                                                                                                               |\n|                | 2. Replace any LGEU P/N 355-022-002 with any S/N not included inRequirement 1 with LGEU P/N 355-022-003, according to the detailed instructions and procedures described in the SB 145-32-0120 original issue or SB 145LEG-32-0032 original issue, as applicable, or later revisions approved by the ANAC.                                                                                                                                                                                       |\n|                | 3. LGEU P/N 355-022-002 may not be installed on any aeroplane as either a replacement spare or new installation.                                                                                                                                                                                                                                                                                                                                                                                 |\n|                | Note: ANAC AD 2009-01-01 and Errata refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Compliance:    | For Requirement 1 - Within the next 12 months after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | For Requirement 2 - Within the next 30 months after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | For Requirement 3 - After 12 September 2011.                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 12 March 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | The ANAC has received a report advising that after commanding the landing gear lever to down the three green landing gear positioning indication was displayed followed by the LG/LEVER DISAGREE EICAS message. The crew decided to continue the approach and landing procedure. As soon as the crew identified that the landing gear was not extended properly, a go-around procedure was successfully performed. During manoeuvre, the aeroplane settled momentarily onto the flaps and belly. |\n\n|     | Since this condition may occur in other aeroplanes of the same type and affects flight safety, a corrective action is required. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n27 January 2009","sortOrder":0},{"sectionNumber":"AD/EMB-145/22","sectionType":"part","heading":"AD/EMB-145/22","content":"## AD/EMB-145/22","sortOrder":1},{"sectionNumber":"Landing Gear Electronic Unit","sectionType":"part","heading":"Landing Gear Electronic Unit","content":"## Landing Gear Electronic Unit","sortOrder":2},{"sectionNumber":"3/2009","sectionType":"part","heading":"3/2009","content":"## 3/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD is narrowly focused on a specific unsafe condition (a landing‑gear indication discrepancy) and prescribes replacement of a single part number across a defined aircraft group. It does not broaden regulatory scope beyond that original safety remediation (no new operational restrictions, no expansion to other systems or aircraft types). Therefore the scope has not grown beyond the original corrective purpose."},"complexity_factors":["Single affected aircraft family (EMB‑135/EMB‑145) and single LGEU part number focus (P/N 355‑022‑002).","Three discrete requirements (replacement for S/N 1000–1999, replacement for other S/N, prohibition on future installation) — straightforward conditional structure.","Two compliance windows (12 months and 30 months) plus an absolute prohibition date (12 Sept 2011) — adds scheduling complexity.","Cross‑reference to two Embraer Service Bulletins (SB 145‑32‑0120 and SB 145LEG‑32‑0032) for procedural detail; later revisions allowed only if ANAC‑approved — introduces dependence on foreign authority approvals.","Limited number of defined technical identifiers (two P/Ns, a S/N range) reduces interpretive complexity.","Reference to ANAC AD and errata — external documents must be checked for complete instructions and any changes.","No complex exemptions or multiple nested exceptions; no operational‑level contingencies (e.g. flight‑by‑flight limitations) — keeps logic simple."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires replacement of a specific model of Landing Gear Electronic Unit (LGEU) on certain Embraer aeroplanes.  Specifically, any Embraer EMB‑135 or EMB‑145 aeroplane that has an LGEU with part number (P/N) 355‑022‑002 must have that unit replaced with LGEU P/N 355‑022‑003.\n- The replacement must follow the procedures set out in Embraer Service Bulletin (SB) 145‑32‑0120 or SB 145LEG‑32‑0032 (original issues), or any later revision approved by the Brazilian aviation authority (ANAC).\n- The AD sets staged compliance times:\n  - If the LGEU P/N 355‑022‑002 has serial numbers (S/N) 1000–1999, replacement is required within 12 months from the AD’s effective date.\n  - If the LGEU P/N 355‑022‑002 has any other serial number, replacement is required within 30 months from the AD’s effective date.\n  - After 12 September 2011, LGEU P/N 355‑022‑002 may not be installed in any aeroplane as a spare or for a new installation.\n- The AD became effective on 12 March 2009.\n\n**Who this affects**\n\n- Aircraft operators and owners of Embraer EMB‑135 and EMB‑145 aeroplanes that are fitted with LGEU P/N 355‑022‑002.\n- Maintenance, repair and overhaul (MRO) organisations and technicians who perform LGEU replacement work (they must follow the specified Embraer SB procedures and any ANAC‑approved revisions).\n- Parts suppliers and operators’ spare parts inventory managers (because P/N 355‑022‑002 is effectively grounded as a future spare after the prohibition date).\n\n**Why it matters (stated rationale and mechanical effect)**\n\n- The Brazilian ANAC reported an incident where the landing gear lever was moved to DOWN, three green gear‑position lights initially displayed, and then an LG/LEVER DISAGREE warning appeared. The crew continued approach, discovered the gear had not properly extended, executed a go‑around, and the aeroplane briefly contacted flaps/belly. The AD adopts ANAC’s corrective action: replace the suspect LGEU units to prevent recurrence.\n\n**Who pays and who decides**\n\n- Aircraft operators/owners pay for parts, labour and any associated downtime. Suppliers and maintenance providers receive business to perform replacements. CASA (via this AD) enforces the requirement in Australia; the replacement procedures are those published by Embraer and any later ANAC‑approved revisions.\n\n**Operational consequences and practical mechanics**\n\n- Operators must inspect records to identify affected LGEUs by part number and serial number ranges and schedule the replacement within the applicable compliance window (12 or 30 months).\n- After 12 September 2011 operators cannot install P/N 355‑022‑002 as a spare or new unit, so affected spares inventories may need write‑downs or disposal/rework.\n- Work must be done in accordance with the Embraer Service Bulletin instructions or later ANAC‑approved revisions, which sets the technical steps and may affect whether the work can be done in‑house or requires specific facilities or approvals.\n\n**Costs, incentives and trade‑offs**\n\n- Direct cost: purchase of replacement LGEU P/N 355‑022‑003, labour and any required testing. These are borne by operators.\n- Timing trade‑offs: the shorter (12‑month) window for S/N 1000–1999 forces earlier scheduling for those units, concentrating maintenance resource demand in the near term for those aircraft.\n- Inventory impact: forbidding re‑installation of P/N 355‑022‑002 after a set date reduces the value of existing spares of that P/N and may create a short‑term surge in demand for the replacement part P/N 355‑022‑003.\n- Safety vs. disruption: the AD does not mandate immediate grounding; it balances safety mitigation by mandating replacement within set timeframes while allowing operators time to schedule work.\n- Implementation risks: availability of replacement units, lead times, capacity at MROs, and the need to follow ANAC‑approved SB revisions could affect how quickly operators comply.\n\n**Where the authority and technical detail come from**\n\n- The directive references Embraer Service Bulletins 145‑32‑0120 and 145LEG‑32‑0032 for procedural detail and seeks ANAC approval for later revisions. ANAC supplied the incident report and corrective-action rationale that underpins the AD.\n\n**Short summary in one sentence**\n\n- This Airworthiness Directive requires Embraer EMB‑135/145 operators to replace LGEU P/N 355‑022‑002 with P/N 355‑022‑003 according to Embraer service instructions within staged time limits, and prohibits future installation of the old unit after 12 September 2011, in response to an ANAC‑reported landing‑gear indication failure."},"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":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific safety-critical component failure. The scope remains precisely limited to the identified landing gear electronic unit defect and the affected Embraer aircraft series. There is no evidence of scope creep; the directive maintains its original narrow safety purpose."},"complexity_factors":["Single, clearly defined applicability (one aircraft type, one specific part number)","Only three straightforward requirements with no nested conditions or exceptions","Simple compliance timeline with three distinct deadlines based on risk categorisation","Minimal cross-referencing (only references to Brazilian aviation authority AD and two Embraer Service Bulletins)","No defined terms section — technical terms (LGEU, P/N, S/N, EICAS) are standard aviation terminology","Background narrative is descriptive rather than creating additional legal conditions","Total length is approximately one page with clear tabular formatting"],"plain_english_summary":"This AD mandates replacement of a faulty Landing Gear Electronic Unit (LGEU) on Embraer EMB‑135/145 aircraft after an incident where indicators falsely showed gear down, causing a near‑accident. It affects operators, owners and maintenance crews and requires swapping the unreliable unit for the improved version within staged timeframes and bans reinstalling the old unit thereafter — preventing false‑positive gear indications and the attendant safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit","history":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit/history","analysis":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit/analysis","conflicts":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit/conflicts","importantCases":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit/important-cases","documents":"/api/acts/ad-emb-145-22-landing-gear-electronic-unit/documents"}}