{"id":"F2008L02859","name":"AD/EMB-145/19 - Horizontal Stabilizer Actuator Clutch Key Washer","slug":"ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74740,"registerId":"commonwealth-F2008L02859-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-145/19 | Horizontal Stabilizer ActuatorClutch Key Washer | 9/2008 |\n| ------------- | ----------------------------------------------- | ------ |\n\n| Applicability: | Embraer EMB-145( ) aircraft.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Verify the Part Number (P/N) and Serial Number (S/N) of the Horizontal Stabilizer Actuator (HSA) units installed on the affected aircraft and perform the following in accordance with instructions and procedures to detailed in Embraer Service Bulletin No.145-27-0088, original issue, or later revisions approved by the CTA.(a) If the P/N of the installed unit is 362200-1011 or 362200-1013, and the unit S/N is included among the following: 0390 through 0408, 0413 through 0439, 0441 through 0487, 0489 through 0504, 0506 through 0508, 0510, 0512 through 0531 or 0534 through 0548, perform a visual inspection of the clutch assembly to verify that at least one of the locking tabs on the key washer is bent against the clutch nut; if none of the locking tabs on the key washer is bent, replace the HSA with a serviceable unit; if at least one of the locking tabs on the key washer is bent, no corrective action is necessary; and(b) If the unit installed is not included among the affected units, according to the list on item (a) above, no additional action is necessary.2. No HSA unit included in the list detailed in Requirement 1(a) above should be installed on an aircraft unless the required inspection in such item is previously performed.Note: DEPARTAMENTO DE AVIAÇÃO CIVIL AD 2002-04-01 refers. |\n| Compliance:    | For Requirement 1 - Within 30 days after the effective date of this AD, unless previously accomplished.For Requirement 2 - From the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This Airworthiness Directive becomes effective on 28 August 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n\n| Background: | There has been a case of looseness of the horizontal stabilizer actuator primary system clutch nut due to incorrect procedures at key washer installation, which caused the loss of both pitch trim control channels. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n17 July 2008","sortOrder":0},{"sectionNumber":"AD/EMB-145/19","sectionType":"part","heading":"AD/EMB-145/19","content":"## AD/EMB-145/19","sortOrder":1},{"sectionNumber":"Horizontal Stabilizer ActuatorClutch Key","sectionType":"part","heading":"Horizontal Stabilizer ActuatorClutch Key Washer","content":"## Horizontal Stabilizer Actuator  \nClutch Key Washer","sortOrder":2},{"sectionNumber":"9/2008","sectionType":"part","heading":"9/2008","content":"## 9/2008","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive confines action to specific HSA part numbers and serial number ranges and requires inspection, replacement if necessary, and an installation prohibition until inspection is done. The text limits remedies to visual inspection and replacement of non‑compliant units to address the reported incorrect key washer installation that caused clutch nut looseness; there is no textual indication that the AD expands beyond that initial, targeted scope."},"complexity_factors":["Targeted technical specificity: identifies exact HSA part numbers (362200-1011, 362200-1013) and multiple serial number ranges — requires accurate record checks and part identification (Requirement 1).","Clear, short compliance window: inspection due within 30 days of effective date — creates scheduling and operational urgency (Compliance).","Prescriptive inspection criterion: visual check for bent locking tab(s) on the key washer; binary pass/fail leads to replacement if not met (Requirement 1(a)).","Replacement obligation and logistic burden: operators must source and install a ‘serviceable unit’ if inspection fails — potential cost and aircraft downtime (Requirement 1(a)).","Installation prohibition: affected HSA units must not be fitted unless the required inspection has been performed — affects maintenance and parts management (Requirement 2).","Dependency on manufacturer documentation and regulator approval: work to be done per Embraer Service Bulletin No.145-27-0088 or later CTA‑approved revisions — some discretion in approved revisions and reliance on external technical instructions (Requirement 1).","Cross-reference to prior AD: note referring to DEPARTAMENTO DE AVIAÇÃO CIVIL AD 2002-04-01 could require checking related compliance history (Note)."],"plain_english_summary":"This Airworthiness Directive requires Embraer EMB-145 operators to check specific horizontal stabilizer actuator units (listed by part and serial number) and inspect the clutch key washer to ensure at least one locking tab is bent against the clutch nut; units without a bent tab must be replaced. It takes effect 28 August 2008 with an inspection deadline of 30 days. The stated purpose is to prevent clutch nut loosening that can cause loss of pitch‑trim control; operators must follow the Embraer service bulletin and bear inspection/replacement costs."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific mechanical defect in a specific aircraft type. The scope remains precisely focused on the horizontal stabilizer actuator clutch key washer issue as originally identified."},"complexity_factors":["Specific part and serial number ranges create conditional logic (P/N 362200-1011 or 362200-1013, with 41 separate serial number ranges)","Nested conditional requirements: inspection only required if specific P/N AND specific S/N, then further conditional action based on visual inspection result","Cross-reference to external technical document (Embraer Service Bulletin No.145-27-0088) for detailed procedures","Reference to Brazilian aviation authority directive (DEPARTAMENTO DE AVIAÇÃO CIVIL AD 2002-04-01)","Two separate compliance deadlines with different triggers (30 days vs immediate)","Technical aviation terminology throughout (HSA, P/N, S/N, clutch assembly, key washer, pitch trim control channels)"],"plain_english_summary":"This CASA airworthiness directive requires operators of certain Embraer EMB‑145 aircraft to inspect specific Horizontal Stabilizer Actuators (HSAs) within 30 days for a factory-installed key washer whose locking tabs must be bent to secure a clutch nut. If tabs aren’t properly bent, the HSA must be replaced and affected units must not be installed until inspected.\n\nIt’s mandatory because a loose nut can disable pitch trim control, risking loss of aircraft pitch authority."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer","history":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer/history","analysis":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer/analysis","conflicts":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer/conflicts","importantCases":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer/important-cases","documents":"/api/acts/ad-emb-145-19-horizontal-stabilizer-actuator-clutch-key-washer/documents"}}