{"id":"F2006B08674","name":"AD/CT58/16 - Fuel Flow Divider Assemblies - Replacement","slug":"ad-ct58-16-fuel-flow-divider-assemblies-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51782,"registerId":"commonwealth-F2006B08674-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 CAR 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/CT58/16 Fuel Flow Divider Assemblies ","sectionType":"part","heading":"AD/CT58/16 Fuel Flow Divider Assemblies - Replacement 5/2002","content":"# AD/CT58/16 Fuel Flow Divider Assemblies \\- Replacement 5/2002\n\nApplicability: Models CT58-140-1, \\-140-2, and former military T58-GE-5, \\-8F, \\-10, \\-100, and \\-402 turboshaft engines, with fuel flow divider assemblies Part Numbers (P/N) 4050T82G02, or 5040T77G02.\n\nRequirement: 1. Locate the temperature control assembly, which is mounted on the fuel flow divider assembly and carry out the following:\n\n    (a) Read the temperature control assembly Serial Number(S/N), located on the temperature control assembly end cap. The end cap can be identified by a one- inch hex flange and by being threaded into the fuel flow divider body.\n\n    (b) If the first two digits of the S/N are 95, 96, 97, 98, or 99, or if the S/N cannot be determined, replace the entire fuel flow divider assembly.\n\n2. Do not install any fuel flow divider assembly with P/N 4050T82G02 or 5040T77G02, that have the first two digits of the temperature control assembly S/N of 95, 96, 97, 98, or 99.\n\nNote: Further information regarding S/N location on the temperature control assembly may be found in GE Alert Service Bulletin CT58 73-A0080, dated 13 February, 2001.\n\nNote: FAA AD 2001-12-07 refers.\n\nCompliance: For Requirements 1 and 2: As from the effective date of this Airworthiness Directive.\n\nThis Airworthiness Directive becomes effective on 16 May 2002.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with narrow, specific scope targeting a known defective part. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific technical requirement with clear part numbers and serial number ranges","No defined terms section or interpretation provisions","No cross-references to other legislation (only references to manufacturer service bulletin and FAA AD for information)","Simple binary compliance test: check serial number → replace if matches criteria","Single compliance date (effective date) with no phased or conditional timelines","Approximately 250 words total"],"plain_english_summary":"This safety order requires operators and maintenance organizations of GE CT58/T58 turboshaft engines (used in helicopters such as the Sikorsky S-61 and Boeing‑Vertol CH‑47) to inspect and remove fuel flow divider assemblies whose temperature‑control parts bear serial numbers beginning 95–99 (or whose numbers are unreadable). Those parts are prohibited from further installation. The rule prevents fuel‑flow failures that can cause engine flameout or uncommanded shutdown."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive is narrowly focused on one identifiable unsafe condition: specific fuel flow divider assemblies with temperature control assembly S/Ns in the 95–99 range (or unreadable). It does not broaden into unrelated areas, add new regulatory powers, or expand coverage beyond the listed engine models and part numbers. Therefore the scope has not grown beyond its original safety-correction purpose."},"complexity_factors":["Short directive: single narrow airworthiness issue focused on two part numbers and a serial-number check","One primary conditional rule: replace if S/N first two digits are 95–99 or S/N unreadable (Requirement 1(b))","Secondary prohibition rule: do not install assemblies of the listed P/Ns with those S/N prefixes (Requirement 2)","Cross-references to manufacturer service bulletin (GE Alert Service Bulletin CT58 73-A0080) and FAA AD for supplementary info","Immediate compliance requirement (no phased compliance or extended inspection intervals)","Few defined terms and minimal nested exceptions (only the unreadable-S/N exception triggers replacement)"],"plain_english_summary":"**What this directive does (mechanically):**\n\n- Applies to General Electric CT58-series turboshaft engines listed in the Applicability paragraph (CT58-140-1, CT58-140-2 and certain former military T58 variants) when they have a fuel flow divider assembly with Part Number (P/N) 4050T82G02 or 5040T77G02.\n\n- Requires maintenance personnel to locate the temperature control assembly mounted on the fuel flow divider assembly and read its Serial Number (S/N) from the end cap (Requirement 1(a)).\n\n- If the first two digits of that S/N are 95, 96, 97, 98 or 99, or if the S/N cannot be read, the entire fuel flow divider assembly must be removed and replaced (Requirement 1(b)).\n\n- Prohibits installing any fuel flow divider assembly with those P/Ns if the temperature control assembly S/N begins with 95–99 (Requirement 2).\n\n- Compliance is required immediately from the directive's effective date (Compliance).\n\n(Notes in the directive point technicians to GE Alert Service Bulletin CT58 73-A0080 for S/N location details and note that a corresponding FAA AD exists.)\n\n**Who this affects:**\n\n- Aircraft owners/operators and maintainers of the specified CT58 and former T58 engine models that use the listed fuel flow divider P/Ns.\n- Maintenance organisations and parts suppliers who perform inspections, replacements, or supply replacement fuel flow divider assemblies for these engines.\n\n**Why it matters (official rationale and practical implications):**\n\n- The directive is presented as necessary to correct an identified unsafe condition related to the temperature control assembly on the fuel flow divider. The mechanical action mandated is inspection of the temperature control assembly S/N and replacement of the fuel flow divider assembly where the S/N falls into the listed ranges or cannot be determined (Requirement 1 and 2).\n\n- Practical effects and implementation considerations:\n  - Who pays: engine/aircraft owners or their operators bear the direct cost of parts, labour and aircraft downtime for the required replacements (Requirement 1(b), Requirement 2).\n  - Who decides: the CASA delegate issued the directive and sets the mandatory requirement; operators and certificated maintenance providers must perform the inspections and replacements in accordance with the AD (Introductory paragraph; Compliance).\n  - Behaviour change: operators must add an S/N check to their maintenance before further flight/use of affected engines; they must remove and replace assemblies with suspect or unreadable S/Ns and must not install assemblies that have the disallowed S/N prefixes (Requirement 1 and 2).\n  - Compliance timing and operational impact: the AD is effective immediately, so inspections/replacements are not optional or phased; this can cause unscheduled maintenance and downtime until replacements are installed (Compliance).\n  - Market and supply effects: demand for replacement fuel flow divider assemblies and maintenance services will rise quickly among the small population of affected engines; suppliers who stock compliant assemblies may benefit, while operators with limited access to parts may face delays and higher short-term costs (Applicability; Requirement 2).\n  - Enforcement and discretion: the AD sets a clear mechanical rule (S/N check and replace); it leaves the specific replacement methods and sourcing to maintainers/operators, subject to normal civil aviation certification and maintenance standards (Requirement; Notes).\n\n**Trade-offs, risks and implementation burden:**\n\n- Costs and opportunity cost: the immediate replacement requirement imposes direct parts and labour costs and aircraft downtime on owners/operators. Those are concentrated costs on the affected operators rather than spread across the industry.\n\n- Compliance burden and risk: determining the S/N requires locating the temperature control assembly end cap; the AD refers to a GE Alert Service Bulletin for locating the S/N, which reduces ambiguity but ties implementers to manufacturer's guidance (Notes). If an S/N is unreadable, the AD requires replacement, which increases parts consumption.\n\n- Substitution effects: operators may seek alternative compatible assemblies or approved overhauled parts; the AD's prohibition targets particular S/N prefixes on specific P/Ns, so substitution to other P/Ns or assemblies with acceptable S/Ns is the permitted route.\n\n- Capture, concentrated benefits or diffuse costs: the directive creates immediate demand for compliant parts and maintenance services. Any concentrated benefit (e.g., to specific parts suppliers) would depend on which suppliers have stock; the AD itself does not create procurement preferences.\n\n**Citations to the directive:**\n- Applicability: lists models and affected P/Ns.\n- Requirement 1(a)–(b): inspection of temperature control assembly S/N and replacement condition.\n- Requirement 2: prohibition on installing assemblies with the disallowed S/N prefixes.\n- Notes: reference to GE Alert Service Bulletin and FAA AD for further information.\n- Compliance: effective immediately from the AD date.\n\n**Bottom line:** The AD mandates immediate inspection of a temperature control assembly S/N on specific CT58/T58 engines and requires replacement of the fuel flow divider assembly when the S/N begins with 95–99 or cannot be read, and bars installation of affected assemblies with those S/N prefixes. The primary impacts are operational (inspection and replacement work), direct costs to owners/operators for parts and downtime, and increased demand for compliant replacement parts and maintenance services."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement","history":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement/history","analysis":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement/analysis","conflicts":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement/conflicts","importantCases":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement/important-cases","documents":"/api/acts/ad-ct58-16-fuel-flow-divider-assemblies-replacement/documents"}}