{"id":"F2008L02131","name":"AD/EMB-145/4 - Engine Thrust Reverser Stow/Transit Switches","slug":"ad-emb-145-4-engine-thrust-reverser-stow-transit-switches","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74363,"registerId":"commonwealth-F2008L02131-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-145/4 | Engine Thrust Reverser Stow/Transit Switches | 8/2008 DM |\n| ------------ | -------------------------------------------- | --------- |\n\n| Applicability: | All EMB-145( ) model aircraft. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Unless previously accomplished, inspect the thrust reversers stow/transit switches on both engine for internal corrosion in accordance with detailed instructions and procedures described in either Embraer Service Bulletin (SB) 145-78-0029, original issue, or SB 145LEG-78-005, original issue, or later revisions approved by the Brazilian Departamento de Aviação Civil (DAC) - Centro Técnico Aeroespacial (CTA) or Agência Nacional de Aviação Civil (ANAC). |\n| | 2. Continue the Requirement 1 inspections. |\n| | The installation, on both engines of an aircraft, of transit switches part number (P/N) 83-990-168, according to either Embraer SB 145-78-0035, original issue, or SB 145LEG-78-0006, original issue, or further revisions approved by the CTA or ANAC, constitutes a terminal action to the repetitive inspections for the transit switches for that aircraft. Additionally, switches P/N 83-990-168, when installed at the stow positions; do not require the repetitive inspections required by this AD. |\n| | Note 1: The “145LEG” series of Embraer Service Bulletins only applies to Legacy executive jets. |\n| | Note 2: DAC AD 2001-05-03R3 refers. |\n| Compliance: | For Requirement 1 - |\n| | a. For aircraft which have logged more than 1,600 hours total time in service (TIS) on 8 June 2001 (the effective date of the original issue DAC AD2001-05-03) - Within the next 400 hours TIS after that date. |\n| | b. For aircraft which have logged 1,600 hours total TIS or below on 8 June 2001 - Before reaching 2,000 hours total TIS after that date. |\n| | For Requirement 2 - Within 1,200 hours TIS after the last inspection and thereafter within every 1,200 hours TIS, until all transit switches on both engines are replaced with a P/N 83-990-168 switch. |\n| | This Airworthiness Directive becomes effective on 23 June 2008. |\n\n| Background: | The DAC have been found cases of internal corrosion of the stow/transit switches installed in the engine thrust reversers of the EMB-145( ) aircraft models. One case of severely contaminated transit switch resulted in uncommanded engine rollback to idle in flight. Spurious messages \"ENG ( ) REV DISAGREE\" have also been displayed in the engine indicating and crew alerting system (EICAS), due to the above internal corrosion, which have induced aborted takeoffs. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n16 June 2008","sortOrder":0},{"sectionNumber":"AD/EMB-145/4","sectionType":"part","heading":"AD/EMB-145/4","content":"## AD/EMB-145/4","sortOrder":1},{"sectionNumber":"Engine Thrust Reverser Stow/Transit Swit","sectionType":"part","heading":"Engine Thrust Reverser Stow/Transit Switches","content":"## Engine Thrust Reverser Stow/Transit Switches","sortOrder":2},{"sectionNumber":"8/2008 DM","sectionType":"part","heading":"8/2008 DM","content":"## 8/2008 DM","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific mechanical defect in thrust reverser switches on a particular aircraft series. The inclusion of both standard and Legacy variants through separate service bulletins represents standard aviation practice for covering aircraft family variants, not scope creep."},"complexity_factors":["Multiple compliance deadlines based on aircraft flight hours as of a specific historical date (8 June 2001)","Cross-references to Brazilian aviation authority approvals (DAC, CTA, ANAC) and foreign service bulletins","Conditional logic: different inspection intervals depending on whether switches have been replaced with P/N 83-990-168","Dual applicability: covers both standard EMB-145 models and Legacy executive jets (via separate service bulletin series)","Nested requirements: Requirement 2 is a continuation of Requirement 1, creating a dependency structure"],"plain_english_summary":"This CASA airworthiness directive orders operators of Embraer EMB‑145 regional and Legacy jets to inspect thrust‑reverser stow/transit switches for internal corrosion, repeating every 1,200 flight hours until a permanent replacement is fitted. Corroded switches have caused uncommanded engine rollback and false warnings leading to aborted takeoffs, so the AD mandates timely inspections and eventual replacement with an ANAC‑approved improved part to restore safe, reliable operation."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD stays within its original safety-focused purpose: detecting and removing corroded thrust-reverser stow/transit switches to prevent spurious indications or unsafe engine/reverser behaviour. It consolidates inspection requirements, sets recurring inspection intervals, and provides a clear terminating action (installation of P/N 83-990-168). It does not introduce regulatory functions outside that safety remit or materially expand the population affected beyond EMB-145 models; therefore the scope has not grown significantly beyond the original intent described in the background and referenced DAC AD."},"complexity_factors":["Short document with a small number of operative requirements (two main requirements: inspection and repetitive inspection/termination)","Conditional compliance windows tied to historical aircraft total time-in-service as of 8 June 2001 (two different deadlines)","Repetitive inspection interval (every 1,200 hours TIS) until a terminating action is taken","Terminating action depends on installing a specific part number (P/N 83-990-168) per listed Embraer Service Bulletins","Cross-references to external documents: two Embraer SBs (including 145LEG variants), and prior DAC AD 2001-05-03R3","Requirement to use later SB revisions only if approved by foreign aviation authorities (DAC/CTA or ANAC) adds an approval/coordination layer","A short clarifying note limiting the 145LEG SB series to Legacy executive jets"],"plain_english_summary":"**What this instrument does (mechanically):**\n\n- Requires operators of Embraer EMB-145 series aeroplanes to inspect the engine thrust-reverser stow/transit switches for internal corrosion (Requirement 1). The inspections must follow the detailed procedures in specified Embraer Service Bulletins (SB 145-78-0029 or SB 145LEG-78-005, or later revisions approved by the Brazilian aviation authority). \n- Requires continued repetitive inspections every 1,200 flight hours until a specified replacement switch is fitted (Requirement 2). \n- Identifies that installing transit switches part number (P/N) 83-990-168 on both engines (per specified Embraer SBs, or later approved revisions) is a terminating action: once those switches are installed the repetitive inspections are no longer required for that aircraft. It also states that switches P/N 83-990-168, when fitted at the stow positions, do not require the repetitive inspections required by this AD. \n\n**Who this affects:**\n\n- Aircraft owners and operators of all Embraer EMB-145 models (including the Legacy executive variant where the SB prefix is 145LEG). \n- Maintenance organisations that perform the inspections and any replacements. \n- Regulators: the directive requires use of Embraer service instructions or later revisions approved by the Brazilian authorities (DAC/CTA or ANAC); the local authority (Civil Aviation Safety Authority in Australia) enforces compliance. \n\n**Why it matters (safety issue and official rationale):**\n\n- The Brazilian authority found cases of internal corrosion in the thrust-reverser stow/transit switches. Corrosion has produced spurious EICAS messages and in one reported case caused an uncommanded engine rollback to idle in flight; corrupt switch signals have also led to aborted takeoffs. The AD aims to detect and remove corroded switches before they create a safety hazard. (Background; Requirement 1 & 2.)\n\n**Compliance timing and mechanics:**\n\n- Initial inspection deadline depends on each aircraft's total time-in-service (TIS) as of 8 June 2001 (the date used in the original DAC AD):\n - If the aircraft had more than 1,600 hours TIS on that date, inspect within the next 400 hours TIS. \n - If the aircraft had 1,600 hours TIS or less on that date, inspect before reaching 2,000 hours TIS. \n- After the initial inspection, repeat inspections every 1,200 hours TIS until both engines have had the P/N 83-990-168 switches installed. (Compliance.)\n- The AD became effective on 23 June 2008.\n\n**What operators must do, who pays, and who decides:**\n\n- Operators must schedule and carry out the inspections using the Embraer service bulletin procedures; they bear the direct costs (labour, inspection tooling, aircraft downtime). \n- If corrosion is found, operators may need further maintenance or replacement parts, which increases costs and potentially causes aircraft grounding. \n- Replacing the existing switches with P/N 83-990-168 removes the need for ongoing inspections; the operator decides whether to incur that upfront cost to eliminate the recurring inspection burden. \n- The service bulletins named are the required work instructions; later revisions are acceptable only if approved by the Brazilian authority (DAC/CTA or ANAC); the CASA (Australian regulator) enforces the AD in Australia. (Requirement text and approval references.)\n\n**Costs, incentives and trade-offs:**\n\n- Concentrated costs fall on EMB-145 operators (inspection labour and parts, plus downtime). \n- The AD creates a clear substitution decision: continue recurrent inspections (recurring labour/downtime cost) or install P/N 83-990-168 switches (upfront parts and fitting cost) to terminate the recurring obligation. \n- If P/N 83-990-168 switches are in short supply or require lead time, operators may face scheduling pressure and potential short-term grounding risk. \n- The AD reduces the risk of spurious EICAS messages and uncommanded reverser/engine behaviour by forcing inspection or replacement; it shifts detection responsibility to operators and maintenance organisations. \n\n**Implementation risks and administrative discretion:**\n\n- The AD depends on following specific Embraer SB procedures or later revisions approved by the Brazilian regulator; differences between SBs and operator practices may create interpretation or approval issues for maintenance organisations. \n- Enforcement and acceptance of later SB revisions rests with the Brazilian authority (DAC/CTA or ANAC) and the Australian regulator for local compliance; that cross-jurisdiction approval path can introduce delay or coordination costs. \n\n**Notes of practical relevance:**\n\n- The SB series labelled 145LEG applies only to Legacy executive jets (Note 1). \n- The AD references an earlier DAC AD (2001-05-03R3) as relevant background (Note 2). \n\n(References: Requirement 1 and 2; Compliance timings; Background; Notes in the AD.)"},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches","history":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches/history","analysis":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches/analysis","conflicts":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches/conflicts","importantCases":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches/important-cases","documents":"/api/acts/ad-emb-145-4-engine-thrust-reverser-stow-transit-switches/documents"}}