{"id":"F2006B03646","name":"AD/BEECH 1900/29 - Electric Trim Servo Cover","slug":"ad-beech-1900-29-electric-trim-servo-cover","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43236,"registerId":"commonwealth-F2006B03646-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 1900/29 - Electric Trim Servo Cover","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBeechcraft 1900 Series Aeroplanes\n\nAD/BEECH 1900/29 Electric Trim Servo Cover 11/99\n\nApplicability: Model 1900D aeroplanes, Serial Numbers UE-1 through UE-246, with electric trim option incorporated.\n\nRequirement: 1. Install electric elevator trim servo covers in accordance with the instructions in Kit No 129-5035-1, as referenced in Raytheon Mandatory Service Bulletin SB 27- 3080 issued October 1998 or Revision 1 issued December 1998.\n\nNote: FAA AD 99-16-12 Amdt 39-11247 refers.\n\nCompliance: 1. Within 600 hours time in service from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 4 November 1999.\n\nBackground: The Federal Aviation Administration has advised that Beech 1900D aeroplanes left the factory without covers installed on the electric elevator trim servos. This could result in failure of the electric elevator trim and difficulty operating the manual trim caused by moisture freezing on parts of the electric actuator installation.\n\nThis Directive requires covers to be installed on electric elevator trim servos to prevent the ingress of moisture.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The Directive applies only to Model 1900D aeroplanes Serial Numbers UE-1 to UE-246 with the electric trim option and requires installation of a specific kit to prevent moisture ingress; it does not broaden or add categories beyond that defined applicability (Applicability; Requirement; Background)."},"complexity_factors":["Narrow applicability: specific model and serial number range, and only aeroplanes with electric trim option (Applicability).","Prescriptive retrofit action: installation must follow a specific kit and Raytheon Mandatory Service Bulletin (Requirement).","Fixed compliance window: deadline expressed as 600 hours time in service from the effective date (Compliance).","Operator cost and logistics: owners/operators must obtain kit, schedule maintenance and pay for installation (Requirement; Compliance).","Dependency on external documents: relies on manufacturer's kit and service bulletin and references FAA AD for background (Requirement; Note; Background).","Low regulatory discretion: directive mandates the action and deadline rather than leaving remedy choices to operators (Requirement; Compliance)."],"plain_english_summary":"This Airworthiness Directive requires Beech 1900D aeroplane operators (Serials UE-1–UE-246) fitted with the electric trim option to install covers on the electric elevator trim servos using Kit No 129-5035-1 per Raytheon Mandatory Service Bulletin. The rule aims to stop moisture ingress that can freeze and disable trim parts (Applicability; Requirement; Background). Owners/operators must arrange and pay for the installation within 600 hours time in service from the effective date (Compliance; Requirement)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive addressing a specific manufacturing defect (missing servo covers) in a limited fleet of aircraft. The scope remains tightly focused on the original safety issue identified by the FAA and adopted by CASA."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (model type and serial number range)","Single straightforward requirement with one specific kit reference","Simple compliance deadline (600 hours from effective date)","No cross-references to other legislation beyond noting the corresponding FAA AD","No conditional logic, exceptions, or nested provisions"],"plain_english_summary":"This is a **safety order for specific aircraft**. It requires owners of certain Beechcraft 1900D aeroplanes (serial numbers UE-1 through UE-246 that have electric trim installed) to fit protective covers over their electric elevator trim servos.\n\n**Why this matters:** Without these covers, moisture can get into the trim system and freeze, which could cause the electric trim to fail and make the manual trim hard to operate. This is a serious flight safety issue.\n\n**What must be done:** Aircraft operators must install the covers using a specific kit (Kit No 129-5035-1) following instructions from a manufacturer service bulletin. This must be done within 600 flight hours of the directive taking effect (4 November 1999).\n\n**Who issued it:** The Civil Aviation Safety Authority (CASA) under Australian civil aviation regulations, implementing a corresponding US Federal Aviation Administration (FAA) safety directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover","history":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover/history","analysis":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover/analysis","conflicts":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover/conflicts","importantCases":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover/important-cases","documents":"/api/acts/ad-beech-1900-29-electric-trim-servo-cover/documents"}}