{"id":"F2006B04687","name":"AD/BELL 47/32 Amdt 2 - Main Rotor Mast Thrust Bearing","slug":"ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44439,"registerId":"commonwealth-F2006B04687-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 47/32 Amdt 2 - Main Rotor Mast Thrust Bearing","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBell Helicopter Textron 47 (All Variants) Series Helicopters\n\nAD/BELL 47/32\n\nAmdt 2\n\n  \nMain Rotor Mast Thrust Bearing 10/86\n\nApplicability: All model 47 series equipped with main rotor mast thrust bearing P/N 47-130-110-1.\n\nRequirement: 1\\. Inspect the engine oil filter for evidence of metal particles. If the installation incorporates a scavenge oil filter, this filter shall also be inspected for metal particles.\n\n2. If metal particles are found during any inspection of the oil filter(s) the source of the contaminant shall be located and eliminated and other components of the engine and transmission which may have been damaged by metal particles shall be inspected and overhauled as prescribed by the appropriate Bell maintenance manual. The main rotor mast thrust bearing P/N 47-130-110-1 shall be thoroughly inspected and replaced with a like component if found to be unserviceable.\n\nNote: FAA AD 62-23-2 and Japan AD TCD 282-2 refers.\n\nCompliance: Paragraph 1 \\- Every 25 hours time in service.\n\nParagraph 2 \\- Before further flight.\n\nBackground: Excessive wear and failure of the main rotor mast thrust bearing have occurred. This Directive has been amended to include Kawasaki-Bell Helicopters.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The original directive (issued October 1986) was amended twice. Amendment 2 specifically expanded the scope to include 'Kawasaki-Bell Helicopters' — Japanese-manufactured versions of the Bell 47. This broadened the directive from covering only US-manufactured Bell helicopters to encompassing all variants globally, including licensed foreign production."},"complexity_factors":["Very short document (under 300 words)","Only 2 substantive requirements with clear sequential logic","Single defined part number (P/N 47-130-110-1)","No cross-references to other legislation sections (only references to related FAA and Japanese directives in a note)","Simple conditional structure: 'If metal found → do X before flying again'","Clear compliance timeframes ('Every 25 hours', 'Before further flight')","Minimal defined terms — only standard aviation terminology"],"plain_english_summary":"This CASA Airworthiness Directive targets Bell 47 series (including Kawasaki‑Bell) helicopters fitted with main rotor mast thrust bearing P/N 47‑130‑110‑1. It requires engine (and scavenge, if fitted) oil‑filter checks every 25 flight hours to detect metal contamination. If metal is found, the helicopter must be grounded until the contamination source is corrected, affected engine/transmission components are inspected/overhauled per Bell's manuals, and the thrust bearing is inspected and replaced if necessary. Failure of this bearing can lead to catastrophic rotor loss."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The Directive was amended to include Kawasaki-Bell helicopters in its applicability, broadening the set of operators required to comply while retaining the same part-number-based technical scope (Background)."},"complexity_factors":["Specific applicability to a single part number (P/N 47-130-110-1) creates targeted compliance (Applicability).","Recurring inspection cadence (every 25 hours) imposes a regular operational maintenance burden (Compliance: Paragraph 1).","Immediate grounding risk and potential cost: required corrective action and replacement before further flight can produce downtime and parts/overhaul costs (Requirement: Paragraph 2; Compliance: Paragraph 2).","Dependency on external technical guidance: overhaul and inspection actions must follow the appropriate Bell maintenance manual, requiring cross-reference and operator access to that manual (Requirement: Paragraph 2).","Judgement and inspection standards: determining whether the thrust bearing is 'unserviceable' and locating the contaminant source requires technician judgment and diagnostic work (Requirement: Paragraph 2).","Cross-references to other airworthiness directives (FAA AD 62-23-2 and Japan AD TCD 282-2) create additional compliance context to be checked by operators (Note).","Scope expansion by amendment to include Kawasaki-Bell affects additional operators and supply chains (Background)."],"plain_english_summary":"Mandates recurring inspections of engine oil filters (and scavenge filter if fitted) for metal particles on all Bell 47 series helicopters fitted with main rotor mast thrust bearing P/N 47-130-110-1. If contamination is found, operators must locate the source, inspect/overhaul affected engine and transmission components per the Bell maintenance manual, and replace the thrust bearing if unserviceable.\n\nInspections are required every 25 flight hours and any required corrective action must be completed before further flight; the amendment extends applicability to Kawasaki-Bell helicopters."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing","history":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing/history","analysis":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing/analysis","conflicts":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing/conflicts","importantCases":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing/important-cases","documents":"/api/acts/ad-bell-47-32-amdt-2-main-rotor-mast-thrust-bearing/documents"}}