{"id":"F2006B02501","name":"AD/AS 355/47 Amdt 1 - MGB Suspension Bi-Directional Cross Beam","slug":"ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41757,"registerId":"commonwealth-F2006B02501-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AS 355/47 Amdt 1 - MGB Suspension Bi-Directional Cross Beam","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)  \nEurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\nAD/AS 355/47\n\nAmdt 1\n\n  \nMGB Suspension Bi-Directional Cross Beam 9/97\n\nApplicability: Model AS 355, versions E, F, F1, F2, and N, fitted with a MGB suspension bi- directional cross beam P/N 350A38.1018, all dash numbers installed on the complete cross beam assemblies P/N 350A38.0210, all dash numbers without Mod No. 072720 embodied.\n\nRequirement: Action in accordance with EUROCOPTER FRANCE AS 355 SB 05.00.29.\n\nNote: DGAC AD 96-155-053(B)R1 refers.\n\nCompliance: Within 30 hours time in service after 4 September 1996; as applicable. Thereafter as specified in the requirement document.\n\nThe initial issue of this directive had effect from 4 September 1996 and the compliance remains unchanged. This amendment has effect from 14 August 1997.\n\nBackground: The manufacturer received an in-service report of a crack in the MGB suspension cross beam.\n\nAmendment 1 alters the Applicability to remove certain modified assemblies, and reference the manufacturer’s definitive Service Bulletin.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment slightly narrows the applicability by excluding modified assemblies, but does not expand beyond the original safety purpose of addressing cracked MGB suspension cross beams. The scope remains tightly focused on the specific mechanical defect."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 2 defined technical identifiers (part numbers P/N 350A38.1018 and P/N 350A38.0210)","Single cross-reference to manufacturer Service Bulletin SB 05.00.29 and French aviation authority DGAC AD 96-155-053(B)R1","Clear, unconditional compliance requirement (30 hours time in service)","Simple amendment logic — only removes applicability for modified assemblies, no nested conditions"],"plain_english_summary":"This AD requires owners/operators of Eurocopter AS 355 E/F/F1/F2/N helicopters fitted with MGB suspension bi‑directional cross beam P/N 350A38.1018 to inspect and, if needed, repair or replace it per the manufacturer’s service instructions (SB 05.00.29). It excludes helicopters already modified by Mod No. 072720. Cracks were found in service and a failed cross beam could detach the main gearbox, so the AD mandates prompt action to prevent catastrophic failure."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. Amendment 1 narrows the directive's scope by excluding certain modified cross beam assemblies (those with Mod No. 072720 embodied) and explicitly references the manufacturer’s Service Bulletin as the definitive corrective-action document. The compliance timeframe remains as originally stated (within 30 hours TIS after 4 September 1996), but fewer assemblies are subject to the mandate following the amendment."},"complexity_factors":["Part‑number and modification‑specific applicability (P/N 350A38.1018; assemblies P/N 350A38.0210; 'without Mod No. 072720 embodied') increases precision and requires operators to check parts and mod status (Applicability).","References an external manufacturer document (EUROCOPTER FRANCE AS 355 SB 05.00.29) for the required technical actions, shifting technical detail out of the directive itself (Requirement).","Short compulsory compliance window (within 30 hours time in service after 4 September 1996) creates operational scheduling and cost pressure for operators (Compliance).","Amendment changes scope by removing certain modified assemblies and endorsing the manufacturer’s SB as definitive, which affects who must act and which assemblies are exempt (Amendment 1).","Multiple model variants covered (AS 355 E/F/F1/F2/N) multiplies affected operators and maintenance records to check (Applicability).","Safety risk driver is an in‑service report of a crack; directive imposes inspection/repair burden on operators rather than prescribing alternative measures (Background, Requirement)."],"plain_english_summary":"This airworthiness directive requires owners/operators of Eurocopter AS 355 (E, F, F1, F2, N) helicopters fitted with a specific MGB suspension cross beam (P/N 350A38.1018) to carry out the inspection/repair actions set out in the manufacturer’s service bulletin. It applies to assemblies without Mod No. 072720 and must be complied with within 30 flight hours after 4 September 1996. The amendment narrows which assemblies are covered and points operators to the definitive service instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam","history":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam/history","analysis":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam/analysis","conflicts":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam/conflicts","importantCases":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam/important-cases","documents":"/api/acts/ad-as-355-47-amdt-1-mgb-suspension-bi-directional-cross-beam/documents"}}