{"id":"F2006B08413","name":"AD/CESSNA 525/4 - Electric Pitch Trim Printed Circuit Board","slug":"ad-cessna-525-4-electric-pitch-trim-printed-circuit-board","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115876,"registerId":"commonwealth-F2006B08413-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nCessna 525 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CESSNA 525/4 Electric Pitch Trim Prin","sectionType":"part","heading":"AD/CESSNA 525/4 Electric Pitch Trim Printed Circuit Board 10/2004","content":"# AD/CESSNA 525/4 Electric Pitch Trim Printed Circuit Board 10/2004\n\nApplicability: Model 525 aeroplanes with the serial numbers 525- 0001, 525-0002, 525-0004\n\nthrough 525-0359 inclusive.\n\nRequirement: 1. If not accomplished previously, replace the elevator trim printed circuit board (PCB) assembly part number (P/N) 6518351-3, 6518351-5 or 6518351-8 with a PCB assembly P/N 6518351-10 in accordance with the Accomplishment Instructions of Cessna Citation Service Bulletin SB525-27-17 dated 9 December 2003 by either:\n\n    Modifying the 6518351-8 trim PCB assembly to a 6518351-10 trim PCB assembly, or\n\n    b. Replacing any 6518351-3 or 6518351-5 trim PCB assembly with a 6518351- 10 (EX) trim PCB assembly.\n\n2. Remove any tie strap (P/N MS3367-1- 4 or equivalent P/N) on the AP SERVOS and PITCH TRIM circuit breakers. (Required by either AD/CESSNA 525/3 original issue or Amdt 1.)\n\n3. Trim PCB assembly P/N 6518351-8, 6518351-3 or 6518351-5 may not be installed on any aeroplane as a replacement part.\n\nNote: FAA AD 2004-14-20 Amdt 39-13729 refers.\n\nCompliance: For Requirement 1 - Within the next two years after the effective date of this Directive or 300 hours time-in-service after the effective date of this Directive, whichever occurs first.\n\nFor Requirement 2 \\- Before further flight after Requirement 1 is accomplished. For Requirement 3 - As of the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 30 September 2004.","sortOrder":1}],"analysis":{"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Directive applies only to the explicitly listed Model 525 serial numbers and updates required parts and actions for those aeroplanes. It modifies in-service parts and procedures but does not expand the numerical scope beyond the stated serial-number range; it references a prior AD for an associated tie‑strap action rather than broadening applicability (Applicability; Requirements 1–3)."},"complexity_factors":["Technical nature: avionics/flight‑control PCB replacement and modification require qualified maintenance resources and parts tracking (Requirement 1).","Alternative compliance routes: option to modify P/N 6518351-8 to 6518351-10 or replace 6518351-3/5 with 6518351-10, increasing tooling/inspection choices (Requirement 1).","Parts prohibition and lifecycle control: older PCB P/Ns 6518351-8/3/5 are explicitly banned as replacements, requiring record checks and inventory management (Requirement 3).","Applicability limited by serial numbers, so operators must inspect records to determine whether the AD applies to a particular airframe (Applicability).","Compliance timing uses a hybrid metric (two years or 300 flight hours) which affects scheduling and operational availability (Compliance for Requirement 1).","External-document reliance: mandatory work must follow Cessna Service Bulletin SB525-27-17 and the AD cross-references FAA AD 2004-14-20, requiring access to and interpretation of those documents (Requirement 1; Note).","Layered requirements: removal of tie strap is linked to a prior AD and must be completed before further flight after Requirement 1, producing sequencing and recordkeeping obligations (Requirement 2; Compliance)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Cessna Model 525 aircraft with serial numbers 525-0001, 525-0002 and 525-0004 through 525-0359 to replace or modify certain elevator trim printed circuit boards to part number 6518351-10, remove a tie strap from specified circuit breakers, and prohibits re‑installation of the older PCB parts. CASA frames the actions as necessary to correct an unsafe condition. Compliance is mandatory and the aircraft owner/operator pays for parts, modification labor and downtime."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific unsafe condition in a limited fleet of aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific technical requirement (circuit board replacement)","Only 3 serial number ranges affected","Clear, sequential compliance deadlines","Minimal cross-referencing (only one FAA AD mentioned in a note)","No nested exceptions or conditional logic","Straightforward applicability section with explicit part numbers"],"plain_english_summary":"This is a safety order (called an \"Airworthiness Directive\") issued by Australia's aviation safety regulator (CASA) for specific Cessna 525 business jets. It requires owners and operators to replace a faulty electric pitch trim circuit board in the aircraft's elevator control system. The old circuit boards (part numbers ending in -3, -5, or -8) must be swapped for an improved version (-10) to prevent potential control problems. Additionally, any plastic tie straps on specific circuit breakers must be removed. The work must be done within 2 years or 300 flight hours (whichever comes first), and the old parts can no longer be used as replacements."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board","history":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board/history","analysis":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board/analysis","conflicts":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board/conflicts","importantCases":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board/important-cases","documents":"/api/acts/ad-cessna-525-4-electric-pitch-trim-printed-circuit-board/documents"}}