{"id":"F2006B02509","name":"AD/AS 355/57 Amdt 1 - Tail Rotor Hub Pitch Change Bearings","slug":"ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41765,"registerId":"commonwealth-F2006B02509-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"For AS 355 E, F, F1, and F2, versions:","sectionType":"part","heading":"For AS 355 E, F, F1, and F2, versions:","content":"# For AS 355 E, F, F1, and F2, versions:\n\nAt 1200 flight hours bearing time since new, thereafter at 1200 flight hours bearing time since new.","sortOrder":0},{"sectionNumber":"Transfer of bearings between models:","sectionType":"part","heading":"Transfer of bearings between models:","content":"# Transfer of bearings between models:\n\nIf bearings are to be transferred from one AS 355 version to another, apply the transfer rules defined in Master Servicing Manual, Chapter 05.99, Page P8.\n\nThis Amendment becomes effective on 31 October 2002.\n\nBackground: This Airworthiness Directive is prompted by advice from the DGAC that cracks have been found in some tail rotor pitch change plate bearings, which can lead to malfunction of the plate and loss of control of the helicopter.","sortOrder":1},{"sectionNumber":"Eurocopter AS 355 (Twin Ecureuil) Series","sectionType":"part","heading":"Eurocopter AS 355 (Twin Ecureuil) Series Helicopters","content":"# Eurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\nAD/AS 355/57 Amdt 1 (continued)\n\nThis Amendment has been issued to reflect compliance that is now relevant. The original is sue of this Directive became effective 7 March 2001.\n\n![](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 24 September 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 9 October 2002.","sortOrder":2}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope. It updates the compliance requirements to reflect current relevance but does not expand beyond the original safety purpose of addressing cracked tail rotor bearings in AS 355 helicopters."},"complexity_factors":["Very short document (approximately 200 words)","Only 1 defined term implicitly referenced (\"bearing time since new\")","Single operational requirement with straightforward interval (1200 flight hours)","One conditional scenario (transfer between models) with external reference to manual","No nested exceptions or complex conditional logic","Clear applicability statement (specific helicopter models only)"],"plain_english_summary":"This Airworthiness Directive mandates recurring inspection or replacement of tail-rotor hub pitch-change bearings on Eurocopter AS355 E/F/F1/F2 helicopters every 1,200 flight hours. It affects owners, operators, and maintenance organisations and is legally enforceable by CASA.\n\nCracked bearings were found that could cause tail-rotor pitch-plate failure and loss of control, so compliance is required. Amendment 1 to the original AD is effective 31 October 2002."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The amendment restates a specific replacement interval and sets a clear reference for bearing transfers to the Master Servicing Manual. The text says the amendment \"reflect[s] compliance that is now relevant,\" indicating clarification rather than an expansion of affected parts or aircraft beyond the original directive."},"complexity_factors":["Narrow technical scope: applies only to tail-rotor pitch change plate bearings on specific AS 355 variants.","Simple compliance trigger: fixed time-based interval (1,200 flight hours since new).","Transfer rule dependency: cross-model transfers must follow a single referenced manual chapter (Master Servicing Manual, Ch.05.99, p. P8).","Operational impact factors: requires accurate flight-hour tracking and scheduling of maintenance/parts availability.","Administrative details: effective date and regulatory administration (Civil Aviation Safety Authority) are specified but add little procedural complexity."],"plain_english_summary":"Requires replacement of tail-rotor pitch-change plate bearings on Eurocopter AS 355 E/F/F1/F2 at 1,200 flight hours since new, and requires that any bearing transfers between AS 355 versions follow the manufacturer's Master Servicing Manual (Chapter 05.99, Page P8). Issued after cracks were found in some bearings, the directive places inspection, replacement and any transfer-compliance costs and associated downtime on aircraft operators and maintenance organisations and is administered by the Civil Aviation Safety Authority."}},"importantCases":[],"_links":{"self":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings","history":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings/history","analysis":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings/analysis","conflicts":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings/conflicts","importantCases":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings/important-cases","documents":"/api/acts/ad-as-355-57-amdt-1-tail-rotor-hub-pitch-change-bearings/documents"}}