{"id":"F2006B08419","name":"AD/CESSNA 550/14 - Indirect (Fluorescent) Lighting System","slug":"ad-cessna-550-14-indirect-fluorescent-lighting-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115888,"registerId":"commonwealth-F2006B08419-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 550/14 - Indirect (Fluorescent) Lighting System","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)  \nCessna 550 (Citation II) Series Aeroplanes\n\nAD/CESSNA 550/14 Indirect (Fluorescent) Lighting System 6/88\n\nApplicability: 1. All models 550 S/No 0561, 0562, 0564 through 0566, 0568 and 0569.\n\n2. All models S550 S/No 0140 through 0146, 0148, 0149.\n\nRequirement: Pull and disable the indirect (fluorescent) lighting system circuit breaker CB275.\n\nNote 1: Cessna Alert Service Letters SLA 550-33-02, SLA S550-33-01 and FAA AD 88-06-02 refer.\n\nNote 2: Compliance with SB 550-33-9 or SB S550-33-5 as applicable will constitute terminating action for this AD.\n\nCompliance: Before next flight following receipt of this AD.\n\nBackground: Cessna has determined that effected aircraft were wired with low voltage wiring instead of the required high voltage wiring. Wire replacement will be accomplished by incorporation of SB550-33-9 and SB S550-33-5 as applicable when issued.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific wiring defect in a limited fleet of aircraft. It has not expanded beyond its original purpose of mitigating an identified fire risk in the Cessna 550 series lighting system."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined applicability groups (specific serial numbers)","Single, unambiguous requirement (disable one circuit breaker)","No nested conditions or cross-references to other legislation","Clear terminating action specified (compliance with specific Service Bulletins)","Minimal regulatory machinery — operates as a standalone safety order"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\n- **Orders immediate action** on certain Cessna 550 Citation II business jets to disable a faulty interior lighting system.\n- **The problem:** Some aircraft were accidentally wired with low-voltage wiring where high-voltage wiring should have been used for the indirect (fluorescent) lighting system. This creates a fire or electrical hazard.\n- **The fix (temporary):** Pilots or maintenance crews must pull and disable circuit breaker CB275 before the next flight — essentially turning off the problematic lighting system.\n- **The fix (permanent):** Aircraft owners must eventually install a proper wiring fix via specific Cessna Service Bulletins (SB 550-33-9 or SB S550-33-5), which will fully resolve the issue and end the need for the temporary workaround.\n\n**Who it affects:**\n- Owners and operators of specific Cessna 550 and S550 aircraft with particular serial numbers (roughly a dozen specific aircraft).\n\n**Why it matters:**\n- **Flight safety.** Incorrect wiring in aircraft lighting systems can cause overheating, smoke, or fire in the cockpit or cabin. This AD ensures the hazard is immediately contained and permanently fixed."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive targets a defined subset of Cessna 550/S550 aircraft by serial number and requires a temporary disablement followed by a wiring replacement via specified service bulletins. The source material does not indicate any expansion or narrowing of that original target; the scope remains confined to the listed serial numbers and the actions described (Applicability; Requirement; Note 2; Background)."},"complexity_factors":["Specific serial-number applicability limits scope but requires checking aircraft records (Applicability).","Immediate mandatory operational action with tight timing (before next flight) creates an urgent compliance burden (Compliance; Requirement).","Permanent remedy depends on incorporation of service bulletins that may be issued later, creating scheduling and monitoring responsibilities (Note 2).","Technical work (wiring replacement) requires qualified maintenance and parts, adding cost and downtime (Requirement; Note 2; Background).","Cross-references to multiple manufacturer and FAA documents require operators to consult additional sources for details (Note 1)."],"plain_english_summary":"Operators of specific Cessna 550 and S550 serial-numbered aircraft must pull and disable circuit breaker CB275 (indirect fluorescent cabin lighting) before the next flight to remove a wiring mismatch hazard. This is mandatory for affected owners/operators and maintenance personnel.\n\nThe directive ties termination to compliance with the listed Cessna service bulletin wiring changes; completing the SB restores the circuit and ends the AD requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system","history":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system/history","analysis":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system/analysis","conflicts":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system/conflicts","importantCases":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system/important-cases","documents":"/api/acts/ad-cessna-550-14-indirect-fluorescent-lighting-system/documents"}}