{"id":"F2006B08459","name":"AD/CF6/15 Amdt 2 - High Pressure Compressor Rear Shaft Bolt Hole","slug":"ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51101,"registerId":"commonwealth-F2006B08459-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/15 Amdt 2 - High Pressure Compressor Rear Shaft Bolt Hole","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/CF6/15\n\nAmdt 2\n\n  \nHigh Pressure Compressor Rear Shaft Bolt Hole 8/95\n\nApplicability: All General Electric CF6-45 and CF6-50 series engines.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 91-10-03 R1 (Amdt. 39-9186).\n\nNote: GE CF6 Service Bulletin 72-958 Rev. 1 also refers.\n\nCompliance: Unless previously accomplished, as specified in the Requirement Document with an effective date of 20 July 1995.\n\nBackground: This Directive currently requires an inspection of the HPC Rear Shaft and a revised bolt configuration to reduce the potential for HPC Shaft fractures. HPC Shaft fractures can result in uncontained engine failures.\n\nThis amendment reflects the requirements of FAA AD 91-10-03 R1 which adds reference to PMA bolts manufactured by Valley-Todeco.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the airworthiness directive. The change is purely additive — adding an approved alternative parts manufacturer (Valley-Todeco) to the existing inspection and modification requirements. The core safety purpose (preventing HPC shaft fractures) and the affected engine models remain unchanged from the original AD/CF6/15."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined term implicitly used (PMA - Parts Manufacturer Approval, mentioned in background but not defined)","No nested conditional logic - single straightforward compliance requirement","No cross-references to other Australian legislation beyond the enabling regulation (CAR 1998 Part 39)","Relies entirely on external technical document (FAA AD 91-10-03 R1) for actual requirements","Simple structure: Applicability → Requirement → Compliance → Background"],"plain_english_summary":"This is a safety directive for aircraft engines. It orders airlines and aircraft operators to inspect and fix a specific mechanical problem in General Electric CF6-45 and CF6-50 jet engines.\n\n**What the problem is:**\nThe High Pressure Compressor (HPC) Rear Shaft has bolt holes that can develop cracks. If the shaft breaks, it can cause an \"uncontained engine failure\" — meaning engine parts could fly out and damage the aircraft or injure people.\n\n**What must be done:**\n- Inspect the HPC Rear Shaft for cracks or damage\n- Install a revised (improved) bolt configuration to prevent fractures\n\n**Who must comply:**\nAnyone operating aircraft with these specific GE engine models (CF6-45 and CF6-50 series). These are commonly used on older Boeing 747s, DC-10s, and Airbus A300s.\n\n**What's new in this version:**\nThis update (Amendment 2) adds approval for using replacement bolts made by a company called Valley-Todeco (PMA bolts). PMA stands for \"Parts Manufacturer Approval\" — these are certified aftermarket parts, not made by GE but approved as safe alternatives.\n\n**Why it matters:**\nThis prevents catastrophic engine failures. The update gives operators more flexibility in sourcing replacement parts while maintaining safety standards."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment does change the instrument’s scope by explicitly adding reference to PMA bolts manufactured by Valley‑Todeco. Mechanically, the original directive already required inspection of the HPC rear shaft and a revised bolt configuration to mitigate shaft fractures (Background). The amendment extends the set of parts and suppliers captured by the directive to include those Valley‑Todeco PMA bolts, thereby affecting which replacement parts and suppliers fall under the directive’s requirements (Background)."},"complexity_factors":["Cross-reference to an external technical document (FAA AD 91-10-03 R1) rather than containing technical steps in the instrument itself (Requirement).","Reliance on a manufacturer service bulletin as supplementary guidance (GE CF6 Service Bulletin 72-958 Rev. 1) (Note).","Technical inspection and hardware-change tasks that require specialised maintenance capability and shop time (Requirement; Compliance).","Narrow applicability limited to specific engine models (Applicability), but potential supply-chain implications from added reference to a specific PMA parts supplier (Background).","Fixed compliance effective date that may create scheduling pressure for operators (Compliance)."],"plain_english_summary":"This instrument requires operators and maintainers of General Electric CF6‑45 and CF6‑50 engines to comply with FAA AD 91‑10‑03 R1 — inspecting the HPC rear shaft and changing its bolt configuration — by 20 July 1995 (unless already done). It affects aircraft operators, maintenance organisations and parts suppliers (including Valley‑Todeco PMA bolts). The goal is to reduce HPC rear‑shaft fractures and uncontained failures; compliance costs (inspections, parts, downtime) fall to operators and maintainers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole","history":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole/history","analysis":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole/analysis","conflicts":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole/conflicts","importantCases":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole/important-cases","documents":"/api/acts/ad-cf6-15-amdt-2-high-pressure-compressor-rear-shaft-bolt-hole/documents"}}