{"id":"F2006B08676","name":"AD/CT58/18 - Fuel Flow Divider Assemblies","slug":"ad-ct58-18-fuel-flow-divider-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51788,"registerId":"commonwealth-F2006B08676-current","compilationNumber":null,"startDate":"2026-04-02","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\nGeneral Electric Turbine Engines \\- CT58 Series","sortOrder":0},{"sectionNumber":"AD/CT58/18 Fuel Flow Divider Assemblies ","sectionType":"part","heading":"AD/CT58/18 Fuel Flow Divider Assemblies 7/2004","content":"# AD/CT58/18 Fuel Flow Divider Assemblies 7/2004\n\nApplicability: General Electric Company (GE) CT58-100-2, CT58-140-1, \\-140-2, and T58-GE-1,\n\n\\-3, -5, -8E, -8F, -10, -100, and -402 turboshaft engines, with fuel flow divider assemblies part number (P/N) 4050T82G02 or 4067T04G02, having temperature control assemblies, P/N 5040T77G02 or 5040T87G02, with serial numbers (SNs) listed in 1.A.(3) of GE Alert Service Bulletin (ASB) No. CT58 S/B 73-A0081, Revision 2, dated August 7, 2003, installed.\n\nRequirement: 1. Locate the temperature control assembly, which is mounted on the fuel flow divider assembly and do the following:\n\n    Read the SN of the temperature control assembly. The SN is located on the end cap of the temperature control assembly. The end cap has a one-inch hex flange and is threaded into the fuel flow divider body.\n\n    b. If the SN is listed in 1.A.(3) of GE ASB No. CT58 S/B 73- A0081, or if the SN cannot be determined, remove the fuel flow divider assembly from service.\n\n2. Do not install any fuel flow divider assembly P/N 4050T82G02 or 4067T04G02, that has a temperature control assembly with a SN listed in 1.A.(3) of GE ASB No. CT58 S/B 73-A0081.\n\nNote: FAA AD 2004-04-06 Amdt 39-13487 refers.\n\nCompliance: For Requirement 1: Within 120 flight hours after the effective date of this Directive.\n\nFor Requirement 2: From the effective date of this Directive. This Airworthiness Directive becomes effective on 8 July 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":2,"scope_assessment":{"changed":false,"description":"This directive is narrowly tailored to address a specific unsafe condition in particular fuel flow divider and temperature control assembly serial numbers. It does not expand the subject beyond that original safety purpose; it requires inspection and removal where the listed SNs (or unreadable SNs) are present, and prohibits installation of those assemblies. There is no evident growth of scope beyond correcting the identified unsafe condition."},"complexity_factors":["Narrow, focused scope limited to specific engine models and two fuel flow divider P/Ns (Applicability)","External dependency on GE Alert Service Bulletin No. CT58 S/B 73-A0081 Rev 2 for the list of affected serial numbers (cross-reference increases practical complexity)","A single conditional: if SN listed or SN cannot be determined, removal is mandatory (simple conditional logic)","Two clear actions: inspect within 120 flight hours; immediate prohibition on installing affected parts (limited number of compliance actions)","Small number of referenced parts and serial-number-based criterion (low definitional load)"],"plain_english_summary":"**What this instrument is and who it applies to**\n\n- This is an Airworthiness Directive (a legally binding safety order for aircraft) that applies to certain General Electric CT58 and T58 turboshaft engines when they have particular fuel flow divider assemblies installed. The affected fuel flow divider part numbers are P/N 4050T82G02 and 4067T04G02, and the temperature control assemblies fitted to those dividers are P/N 5040T77G02 or 5040T87G02 with certain serial numbers (see the GE Alert Service Bulletin list referenced in the directive). (Applicability)\n\n**What the directive requires (mechanics)**\n\n- Inspect the temperature control assembly mounted on the fuel flow divider to read its serial number (SN) from the end cap. (Requirement 1)\n- If the SN is on the list in section 1.A.(3) of GE Alert Service Bulletin No. CT58 S/B 73-A0081 (Revision 2, dated 7 Aug 2003), or if the SN cannot be determined, the fuel flow divider assembly must be removed from service. (Requirement 1.b)\n- From the effective date of the directive, you must not install any fuel flow divider assembly (P/N 4050T82G02 or 4067T04G02) that has a temperature control assembly with an SN listed in that GE service bulletin. (Requirement 2)\n- Timing: the inspection and any removal required must be done within 120 flight hours after the directive becomes effective; the installation prohibition is immediate. (Compliance)\n\n**Why it matters (official rationale and practical test)**\n\n- The stated purpose is to correct an unsafe condition associated with these fuel flow divider / temperature control assemblies (the directive cites a GE service bulletin and an FAA AD as the source of the identified problem). That is the official claim of risk and the reason for mandatory action. (Applicability; Requirement; Note referring to FAA AD 2004-04-06)\n\n- Practical effects and trade-offs:\n  - Who pays: aircraft owners/operators pay for the inspection, any removal and replacement parts, and downtime for the work. (Requirement; Compliance)\n  - Who decides: the operator (or their maintenance organisation) locates the SN and decides whether removal is necessary; the regulator enforces compliance with the directive. (Requirement)\n  - Behaviour change: operators of affected engines must inspect and, where necessary, remove/replace fuel flow divider assemblies; they must not fit dividers with the listed SNs. This reduces the pool of available spares and may increase parts lead times or costs. (Requirement 1, Requirement 2)\n  - Cost and operational impact: removal and replacement may require shop time and grounding or reduced availability of aircraft until compliant parts are fitted; if the SN cannot be read, the directive forces removal, which increases safety margin at the cost of replacing possibly serviceable parts. (Requirement 1.b; Compliance)\n  - Implementation risk: the directive relies on an external list of serial numbers in a GE Alert Service Bulletin (an external document). That creates a dependency — accurate identification depends on accessing and interpreting that bulletin. There is also a simple but important conditional: inability to read the SN triggers mandatory removal, so inspections must be able to access and read the end cap. (Applicability; Requirement 1; GE ASB reference)\n\n**Other practical notes**\n\n- The directive is narrowly targeted by part numbers and serial numbers. It does not order fleet-wide component replacement — it orders selective removal for assemblies with specified serial numbers or when the SN cannot be determined. (Applicability; Requirement)\n- The directive cross-references a GE Alert Service Bulletin (CT58 S/B 73-A0081 Rev 2) for the list of affected serial numbers and to the FAA AD 2004-04-06. Operators must consult that service bulletin to know which serial numbers are affected. (Applicability; Note)\n\n**Net summary**\n\n- Mechanically: read the serial number on the temperature control assembly; if it is on the listed SNs or unreadable, remove the fuel flow divider from service; do not install dividers with those listed SNs. The inspection must be done within 120 flight hours; the installation bar is immediate. (Requirement; Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific unsafe condition in defined engine models. The scope remains precisely limited to the identified fuel flow divider assemblies with the specified temperature control components. There is no evidence of scope creep beyond the original safety purpose."},"complexity_factors":["Heavy reliance on external technical documents (GE Alert Service Bulletin CT58 S/B 73-A0081) for serial number lists — the AD itself doesn't contain the full list of affected parts","Nested part number and serial number conditions requiring cross-referencing between multiple documents (AD, FAA AD 2004-04-06, GE service bulletin)","Specific technical terminology requiring aviation engineering knowledge (turboshaft engines, fuel flow divider assemblies, temperature control assemblies, part numbers, serial numbers)","Dual compliance deadlines (120 flight hours for inspection/removal, immediate for installation prohibition)"],"plain_english_summary":"This AD requires operators and maintainers of GE CT58/T58 turboshaft engines to inspect the fuel flow divider’s temperature control assembly for specified serial numbers and remove any affected or unreadable assemblies within 120 flight hours. The assemblies must not be reinstalled from the AD’s effective date. It targets a fault that can cause unsafe fuel distribution, risking engine failure or fire, so immediate compliance is mandatory."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies","history":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies/history","analysis":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies/analysis","conflicts":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies/conflicts","importantCases":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies/important-cases","documents":"/api/acts/ad-ct58-18-fuel-flow-divider-assemblies/documents"}}