{"id":"F2006B08529","name":"AD/CFM56/4 - Garrett Air Turbine Starter - Improved Clutch","slug":"ad-cfm56-4-garrett-air-turbine-starter-improved-clutch","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51287,"registerId":"commonwealth-F2006B08529-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CFM56/4 - Garrett Air Turbine Starter - Improved Clutch","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  CFM International Turbine Engines - CFM56 Series\n\n \n\nAD/CFM56/4  Garrett Air Turbine Starter - Improved Clutch 8/94 Applicability:              All CFM56-5A1 engines equipped with Garrett air turbine starter, P/N 3505582-1. Requirement:              Incorporate CFM International Service Bulletin CFM56-5 No 80-003.\n\nNote: DGAC AD 94-099(B) also refers.\n\n \n\nCompliance: Unless previously accomplished, at the first starter shop visit after 21 July 1994 but no later than 31 December 1994.\n\n \n\nBackground:  This Directive has been issued to prevent starter failures and consequent heat damage to the electronic engine control (FADEC) harnesses.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive keeps a narrowly focused scope: it applies only to CFM56-5A1 engines fitted with Garrett air turbine starter P/N 3505582-1 and requires incorporation of the specified service bulletin to address starter failures and FADEC harness heat damage. The text does not expand the affected population or the types of corrective action beyond incorporation of Service Bulletin CFM56-5 No 80-003, and it sets a clear compliance window (first starter shop visit after 21 July 1994 but no later than 31 December 1994). (See: \"Applicability\", \"Requirement\", \"Compliance\" and \"Background\")."},"complexity_factors":["Narrow technical scope: applies only to CFM56-5A1 engines fitted with Garrett starter P/N 3505582-1 (\"Applicability\").","Prescriptive compliance timing: tied to next starter shop visit with an absolute calendar cutoff (\"Compliance\").","Implementation depends on an external technical document (CFM Service Bulletin CFM56-5 No 80-003), which contains the detailed engineering instructions (\"Requirement\").","Requires physical shop work and parts replacement/modification, so practical complexity is in maintenance execution rather than legal interpretation (\"Requirement\").","Cross-reference to a foreign airworthiness directive (DGAC AD 94-099(B)) adds coordination factors for internationally operated fleets (\"Note\")."],"plain_english_summary":"This Directive requires retrofit of Garrett air turbine starter P/N 3505582‑1 on all CFM56‑5A1 engines per CFM International Service Bulletin CFM56‑5 No 80‑003. It binds engine owners/operators to have the mod done at the first starter shop visit after 21 July 1994, and by 31 December 1994 at the latest. The change aims to prevent starter failures and FADEC‑harness heat damage; operators bear the work, parts and scheduling burden, with a trade‑off between waiting for a shop visit and meeting the hard deadline."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow, specific scope. It addresses exactly one mechanical defect in one engine configuration. There is no evidence of scope creep; the directive remains tightly focused on its original purpose of preventing starter failures and heat damage to engine control systems."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined applicability criterion (specific engine model and part number)","Single, unambiguous compliance requirement (follow the Service Bulletin)","No nested exceptions or conditional logic","No cross-references to other legislation beyond a single note about a related French directive","Clear, fixed deadline with simple alternative timing (first shop visit OR hard date)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific aircraft engines to fix a known safety problem.\n\n**What it does:**\n- Targets **CFM56-5A1 jet engines** that use a specific **Garrett air turbine starter** (part number 3505582-1)\n- Requires these engines to have their starter clutch upgraded following manufacturer's instructions (Service Bulletin CFM56-5 No 80-003)\n\n**Why it matters:**\n- Faulty starter clutches were failing and generating excessive heat\n- This heat was damaging **FADEC harnesses** — the wiring that controls the engine's computer (FADEC stands for \"Full Authority Digital Engine Control,\" essentially the engine's brain)\n- Damaged harnesses could lead to engine control failures, creating serious flight safety risks\n\n**Who must comply:**\n- Airlines and aircraft operators using affected engines\n- Maintenance organisations performing \"starter shop visits\" (routine maintenance on the starter motor)\n\n**Deadline:**\n- The upgrade had to happen at the first maintenance visit after 21 July 1994, but absolutely no later than 31 December 1994\n\n**Note:** This references a French aviation safety order (DGAC AD 94-099(B)), showing international coordination on this safety issue."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch","history":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch/history","analysis":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch/analysis","conflicts":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch/conflicts","importantCases":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch/important-cases","documents":"/api/acts/ad-cfm56-4-garrett-air-turbine-starter-improved-clutch/documents"}}