{"id":"F2006B08358","name":"AD/CESSNA 400/75 - Horizontal Stabiliser Leading Edge Assembly and Elevator Trim Tab Actuator - Replacement","slug":"ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115765,"registerId":"commonwealth-F2006B08358-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 400/75 - Horizontal Stabiliser Leading Edge Assembly and Elevator Trim Tab Actuator - Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Cessna 400 Series Aeroplanes\n\n \n\n# AD/CESSNA 400/75 Horizontal Stabiliser Leading Edge Assembly\n\nand Elevator Trim Tab Actuator - Replacement\n\nApplicability: All models 404 with S/Nos. 404-0001 to 404-0637.\n\n \n\nRequirement: 1. Modify the horizontal stabiliser by replacing the leading edge assembly in accordance with Cessna Service Kit SK404-31 as revised 23 June 1980.\n\n# 10/80\n\n \n\n2. Modify the elevator trim system by replacing the trim tab actuator in accordance with Cessna Service Kit SK404-31 as revised 23 June 1980.\n\n \n\nCompliance: 1. Before 1 March 1981.\n\n \n\n2. Unless already accomplished, before 1 March 1981.\n\n \n\nBackground:  These replacements will eliminate the RPM limitation and the recurring trim tab actuator screw replacement requirement of Cessna SIL ME80-2, Revision 2.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive for a specific aircraft type. It has not expanded beyond its original purpose of mandating specific hardware replacements for safety reasons."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined applicability criteria (model 404, specific serial number range)","2 straightforward mechanical requirements with clear reference to manufacturer service kit","Single compliance deadline with simple 'unless already accomplished' exception","No cross-references to other legislation or regulations beyond the enabling Civil Aviation Regulations 1998","No conditional logic, nested exceptions, or discretionary provisions"],"plain_english_summary":"Owners/operators of early Cessna 404s (s/n 404‑0001 through 404‑0637) must, per CASA AD, replace the horizontal stabiliser leading edge assembly and the elevator trim tab actuator to eliminate an engine RPM restriction and recurring trim‑actuator failures. Compliance required by 1 March 1981 using Cessna Service Kit SK404‑31 (rev. 23 June 1980)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive keeps a narrowly targeted scope: it applies only to the listed serial-numbered Cessna 404 aeroplanes and mandates component replacement per Cessna SK404-31 (rev. 23 June 1980) by 1 March 1981 (Applicability; Requirement 1 & 2; Compliance). The stated purpose is to remove an existing RPM limitation and recurring trim-tab screw replacement requirement (Background). The instrument does not expand the fleet coverage or add other obligations beyond those replacements."},"complexity_factors":["Narrow, clear applicability limited to Cessna 404 S/Ns 404-0001 to 404-0637 (Applicability).","Action is technical and part-specific: replace leading edge assembly and trim-tab actuator (Requirement 1 & 2).","Obligation references an external document — Cessna Service Kit SK404-31 (rev. 23 June 1980) — requiring access to and reliance on that kit (Requirement 1 & 2).","Firm compliance deadline creates scheduling and cost pressure on operators (Compliance: before 1 March 1981).","No alternative methods or exemptions are stated in the text, so operators must follow the specified kit (Requirement).","Safety-critical flight-control components are involved, requiring qualified maintenance and parts availability (Requirement; Background)."],"plain_english_summary":"Requires owners/operators of Cessna 404 aeroplanes (S/N 404-0001 to 404-0637) to replace the horizontal stabiliser leading edge assembly and the elevator trim-tab actuator using Cessna Service Kit SK404-31 (rev. 23 June 1980). The work must be done by 1 March 1981. The replacements are intended to remove an RPM limitation and the need for recurring trim-tab actuator screw replacements. Owners bear the cost and must arrange compliance by the specified date."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem","history":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem/history","analysis":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem/analysis","conflicts":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem/conflicts","importantCases":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem/important-cases","documents":"/api/acts/ad-cessna-400-75-horizontal-stabiliser-leading-edge-assembly-and-elevator-trim-tab-actuator-replacem/documents"}}