{"id":"F2006B08497","name":"AD/CF6/8 - Low Pressure Turbine Cooling Air Manifold","slug":"ad-cf6-8-low-pressure-turbine-cooling-air-manifold","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51200,"registerId":"commonwealth-F2006B08497-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/8 - Low Pressure Turbine Cooling Air Manifold","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nGeneral Electric Turbine Engines \\- CF6 Series\n\nAD/CF6/8 Low Pressure Turbine Cooling Air Manifold 4/87\n\nApplicability: CF6-45,-50 series engines.\n\nRequirement: 1. Carry out the requirements of General Electric SB 75-55 Paragraph 2.\n\n    2. Inspect left hand side 7th stage low pressure turbine cooling air manifold tubes in accordance with the requirements of General Electric SB 75-58 Paragraphs 2A, 2B, 2C and 2D(4)(b).\n\n    3. Remove 7th stage low pressure turbine cooling air tubes and carry out a fluorescent \\- penetrant inspection in accordance with the requirements of General Electric CF6-50 Task Numbered Shop Manual, GEK 50481.\n\nReference Documents:\n\nFAA AD 85-25-56 R1\n\nG.E. SB 75-55 R2\n\nG.E. SB 75-58\n\nG.E. CF6-50 Task Numbered Shop Manual, GEK 50481 Compliance: 1. Unless already accomplished \\- Prior to 31 March 1987.\n\n    2. At intervals not to exceed 250 cycles.\n\n    3. At each scheduled engine shop visit.\n\nBackground: This Directive has been issued to require inspection of the 7th stage low pressure turbine cooling air manifold tubes. Failure of the cooling air manifold tubes could result in an overtemperature condition of the low pressure turbine and subsequent 1st stage turbine disc rupture.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive, as written, applies only to CF6‑45 and CF6‑50 engines and prescribes inspections/removals described in the Requirements and Compliance sections. The text shows no expansion of applicability or addition of new regulatory powers beyond mandated maintenance actions tied to the stated safety concern (Background)."},"complexity_factors":["Technical specificity: targets a particular engine component (7th‑stage LP turbine cooling‑air manifold tubes), requiring specialist inspection skills and tooling (Requirement 2–3).","Multiple external references: depends on G.E. SB 75‑55, G.E. SB 75‑58, GEK 50481 and FAA AD 85‑25‑56 R1 for inspection methods and criteria (Reference Documents).","Operational cadence: mixes a one‑off deadline (Compliance 1), short recurring interval (every 250 cycles, Compliance 2) and shop‑visit requirement (Compliance 3), creating overlapping scheduling obligations.","Work scope: includes removal and fluorescent‑penetrant inspection, which increases labour, equipment and downtime compared with visual checks (Requirement 3).","Clear legal prescription: the AD sets specific actions and timings, reducing regulatory discretion but increasing compliance monitoring needs."],"plain_english_summary":"Requires inspection, removal and fluorescent‑penetrant testing of the 7th‑stage low‑pressure turbine cooling‑air manifold tubes on GE CF6‑45 and CF6‑50 engines. It prescribes an initial deadline (by 31 March 1987 if not already done), recurring inspections every 250 cycles, and checks at every scheduled shop visit (Requirements 1–3; Compliance). The stated purpose is to prevent overtemperature and possible 1st‑stage turbine disc rupture. Operators bear inspection, removal and shop costs and incur recurring downtime and scheduling burden."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific engine models. It has not expanded beyond its original purpose of preventing turbine disc ruptures due to cooling manifold failures."},"complexity_factors":["Short, single-purpose directive with only 3 technical requirements","Heavy reliance on external technical documents (4 referenced GE manuals/bulletins) — compliance requires obtaining and interpreting manufacturer documentation not contained in the AD itself","Specific technical terminology requiring aviation engineering knowledge ('fluorescent penetrant inspection', '7th stage low pressure turbine cooling air manifold tubes')","Multiple compliance timeframes (one-time deadline, recurring cycle limit, and event-triggered requirement) creating three separate obligations","No defined terms section or interpretation provisions — assumes reader has aviation regulatory context"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and removal/fluorescent-penetrant inspection of specific low-pressure turbine cooling tubes on GE CF6-45/50 engines, following GE technical procedures, to detect cracks that could cause overheating and catastrophic turbine-disc rupture. It applies to Australian operators of aircraft using these engines and requires initial and recurring checks (initial by 31 Mar 1987, then every 250 flight cycles and during shop visits)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold","history":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold/history","analysis":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold/analysis","conflicts":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold/conflicts","importantCases":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold/important-cases","documents":"/api/acts/ad-cf6-8-low-pressure-turbine-cooling-air-manifold/documents"}}