{"id":"F2009L01554","name":"AD/ERJ-190/20 - Outboard Slat Skew Sensor","slug":"ad-erj-190-20-outboard-slat-skew-sensor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":78257,"registerId":"commonwealth-F2009L01554-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Embraer ERJ-190 Series Aeroplanes","sectionType":"division","heading":"Embraer ERJ-190 Series Aeroplanes","content":"### Embraer ERJ-190 Series Aeroplanes\n\n| AD/ERJ-190/20 | Outboard Slat Skew Sensor | 5/2009 |\n| ------------- | ------------------------- | ------ |\n\n| Applicability: | Model ERJ 190-100 ECJ, ERJ 190-100 IGW, ERJ 190-100 LR, ERJ 190-100 STD, ERJ 190-200 IGW, ERJ 190-200 LR and ERJ 190-200 STD aeroplanes equipped with the outboard slat skew sensor part number (P/N) 1702286A or 1702288A. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Perform an operational check (OPC) of the outboard slat skew sensor P/N 1702286A or P/N 1702288A in accordance with Aircraft Maintenance Manual (AMM) Task 27-83-01-710-801-A “Outboard Slat Skew Sensor - Operational Test”. |\n| | 2. If during the Requirement 1 OPC, an outboard slat skew sensor failure is found, replace it with a serviceable one. |\n| | Note 1: For the purpose of this Directive, an operational check (OPC) is: “A task to determine if an item is fulfilling its intended purpose. Since it is a failure finding task, it does not require quantitative tolerances.” |\n| | Note 2: For the purpose of this Directive, a serviceable sensor is one that has passed the Requirement 1 OPC. |\n| | Note 3: ANAC AD 2009-02-03 refers. |\n| Compliance: | For Requirement 1 - Initially, if not previously accomplished, within the next 1,320 hours time in service (TIS) after the effective date of this Directive and thereafter at intervals that do not exceed 1,320 hours TIS. |\n| | For Requirement 2 - Before further flight after the Requirement 1 OPC is accomplished. |\n| | This Airworthiness Directive becomes effective on 7 May 2009. |\n| Background: | The Brazilian Agência Nacional de Aviação Civil (ANAC) has advised that occurrences of outboard slat skew sensor failure in open or closed position have been found. The combination of an outboard slat skew sensor failed closed, an outboard slat actuator structural failure (rupture) and its adjacent actuator torque limiter failing high (allows higher loads to the panel structure) occurring in the same slat surface, under normal flight loads, may lead slat surface to detach from wing with the possibility of hitting and damaging the horizontal stabilizer and elevator, which may affect the aeroplane’s controllability. |\n\n| | Since this condition affects flight safety, a corrective action is required. Thus, sufficient reason exists to mandate the operational check. |\n| --- | --------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n26 March 2009","sortOrder":0},{"sectionNumber":"AD/ERJ-190/20","sectionType":"part","heading":"AD/ERJ-190/20","content":"## AD/ERJ-190/20","sortOrder":1},{"sectionNumber":"Outboard Slat Skew Sensor","sectionType":"part","heading":"Outboard Slat Skew Sensor","content":"## Outboard Slat Skew Sensor","sortOrder":2},{"sectionNumber":"5/2009","sectionType":"part","heading":"5/2009","content":"## 5/2009","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a tightly scoped, single-purpose safety mandate. The scope remains precisely targeted at addressing the specific sensor failure mode identified by the Brazilian authority, with no evidence of scope creep or expansion beyond the original safety concern."},"complexity_factors":["Single, clearly defined applicability (7 specific aircraft models with 2 specific part numbers)","Only 2 substantive requirements with straightforward conditional logic (if failed, then replace)","3 brief definitional notes clarifying technical terms","Simple compliance timeline (initial check + recurring interval of 1,320 hours)","No cross-references to other legislation beyond a single reference to the Brazilian authority's equivalent directive (ANAC AD 2009-02-03)","Background section provides clear safety rationale without legal convolution","Total length is approximately 300 words of substantive content"],"plain_english_summary":"This AD mandates operators of certain Embraer ERJ‑190s fitted with outboard slat skew sensors (P/N 1702286A or 1702288A) to perform regular operational checks and replace any failed sensor before flight. \n\nIt addresses a hazard where a sensor failing closed, combined with slat‑actuator and restraint failures, could allow a slat to detach and strike the tail, risking loss of control. Checks are required at initial and recurring intervals of 1,320 flight hours."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive is narrowly tailored to detect and remove failed outboard slat skew sensors on specific ERJ‑190 aeroplanes. It imposes a single recurring inspection and an immediate replacement requirement for failed items. This falls within the original safety purpose (to mitigate slat detachment risk identified by ANAC) and does not broaden obligations beyond that technical, safety‑focused scope."},"complexity_factors":["Narrow applicability confined to specific ERJ‑190 models and two sensor part numbers (P/N 1702286A, 1702288A).","Single recurring task mandated: one Operational Check (AMM Task 27-83-01-710-801-A).","Simple failure-response rule: replace failed sensor before further flight (no multi-step remedies).","One defined interval for recurrence: 1,320 hours TIS (initial and recurring).","Two short definitional notes (definition of OPC and what constitutes a serviceable sensor), no extensive definitions section.","One external cross-reference to ANAC AD 2009-02-03 and one AMM task reference — limited cross-referencing only."],"plain_english_summary":"**What this directive does (mechanical change)**\n\n- Requires operators of certain Embraer ERJ-190 aeroplanes to perform a specific operational check (OPC) on the outboard slat skew sensor (part number 1702286A or 1702288A) using the Aircraft Maintenance Manual task 27-83-01-710-801-A. (See: Requirement 1.)\n- If the OPC shows the sensor has failed, the sensor must be replaced with a sensor that has passed the OPC before the aeroplane flies again. (See: Requirement 2.)\n- The first check must be done within 1,320 hours time in service (TIS) after the directive becomes effective (if not already done), and then repeated at intervals not exceeding 1,320 hours TIS. (See: Compliance.)\n\n**Who is affected**\n\n- Operators of Embraer ERJ-190 series aeroplanes listed in the Applicability (models ERJ 190‑100 and ERJ 190‑200 variants) that are equipped with the outboard slat skew sensor P/N 1702286A or 1702288A. (See: Applicability.)\n\n**Why it matters (stated rationale and safety mechanism)**\n\n- The Brazilian aviation authority (ANAC) found incidents where these sensors failed in either the open or closed position. The directive cites a chain of failures — a skew sensor failed closed, an outboard slat actuator structural rupture, and the adjacent actuator torque limiter allowing higher loads — that could allow a slat surface to detach and strike the horizontal stabilizer/elevator, potentially affecting controllability. The directive therefore mandates the OPC to detect failed sensors and require replacement where failures are found. (See: Background; Requirement 1–2.)\n\n**How it works in practice**\n\n- The OPC is a failure-finding task defined in the directive as a check to determine if the item is performing its intended purpose; it does not require quantitative tolerances. A “serviceable” sensor is one which passes that OPC. (See: Note 1 and Note 2.)\n- If a sensor fails the OPC, the operator must replace it before the next flight (immediate remedy). If the sensor passes, the aircraft continues in service until the next scheduled OPC within 1,320 hours TIS.\n\n**Costs, incentives and trade-offs (practical effects for operators and the regulator)**\n\n- Direct compliance cost: labour to perform the OPC at the required interval, any diagnostic time, and parts cost where replacement is needed (Requirement 1–2; Compliance).\n- Operational impact: if a failed sensor is found the aeroplane cannot fly until a replacement is installed, creating potential schedule disruption and revenue loss for the operator (Requirement 2).\n- Spare and maintenance planning: operators must ensure availability of appropriate spare sensors (P/N 1702286A or 1702288A) and trained personnel or facilities able to perform the AMM task referenced (Requirement 1; AMM task reference).\n- Safety benefit is concentrated (reduced risk of slat detachment on affected aeroplanes) while the compliance cost is borne by the operators of those specific aircraft.\n- Implementation risk: the directive depends on correct execution of the AMM task and accurate fault detection by the OPC. False negatives could leave a failed sensor undetected; false positives would impose unnecessary replacement cost. The directive defines the OPC as a failure‑finding task but does not set a quantitative acceptance criterion (Note 1), so operator interpretation and recordkeeping matter.\n- Market effect: modest increase in demand for the specified sensor part numbers and associated maintenance services; no change to ownership or operational authorisations.\n\n**Administrative and enforcement points**\n\n- The directive cross‑references an ANAC AD (ANAC AD 2009‑02‑03). Compliance is mandatory for applicable aircraft, and the directive sets the effective date and the compliance interval (Compliance; Effective date).\n\n**Net practical summary**\n\n- If you operate an affected ERJ‑190 with either P/N 1702286A or 1702288A slat skew sensors, you must carry out an operational check every 1,320 hours TIS and replace any sensor that fails before the aeroplane flies again. The action is intended to detect and remove failed sensors that, in combination with other failures, could allow a slat to detach and impair controllability (Requirement 1–2; Background)."},"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-erj-190-20-outboard-slat-skew-sensor","history":"/api/acts/ad-erj-190-20-outboard-slat-skew-sensor/history","analysis":"/api/acts/ad-erj-190-20-outboard-slat-skew-sensor/analysis","conflicts":"/api/acts/ad-erj-190-20-outboard-slat-skew-sensor/conflicts","importantCases":"/api/acts/ad-erj-190-20-outboard-slat-skew-sensor/important-cases","documents":"/api/acts/ad-erj-190-20-outboard-slat-skew-sensor/documents"}}