{"id":"F2008L01625","name":"AD/DAUPHIN/68 Amdt 2 - Main Gearbox Base Plate","slug":"ad-dauphin-68-amdt-2-main-gearbox-base-plate","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":73871,"registerId":"commonwealth-F2008L01625-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter SA 360 and SA 365 (Dauphin) S","sectionType":"division","heading":"Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters","content":"### Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\n| AD/DAUPHIN/68 Amdt 2 | Main Gearbox Base Plate | 6/2008 |\n| -------------------- | ----------------------- | ------ |\n\n| Applicability: | All SA 365 N, N1, and AS 365 N2, N3 helicopters, all serial numbers, equipped with a main gearbox base plate before embodiment of MOD 0763C45.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. On SA 365 N, N1, helicopter versions:a. Equipped with a MGB that has logged less than 9,900 flight cycles and has never been overhauled or repaired:- Action in accordance with paragraph 2.B. of Eurocopter Alert Service Bulletin (ASB) 05.00.45 R1 or latter approved revision.b. Equipped with a MGB that has logged 9,900 or more flight cycles, and has never been overhauled or repaired:- Action in accordance with paragraph 2.B. of ASB 05.00.45 R1 or latter approved revision.c. Equipped with a newly overhauled or newly repaired MGB:- Action in accordance with paragraph 2.B. of ASB 05.00.45 R1 or latter approved revision.2. On AS 365 N2, N3, helicopter versions:a. Equipped with a MGB that has logged less than 7,300 flight cycles and has never been overhauled or repaired:- Action in accordance with paragraph 2.B. of ASB 05.00.45 R1 or latter approved revision.b. Equipped with a MGB that has logged 7,300 or more flight cycles and has never been overhauled or repaired:- Action in accordance with paragraph 2.B. of ASB 05.00.45 R1 or latter approved revision. |\n\n|             | c. Equipped with a newly overhauled or newly repaired MGB:- Action in accordance with paragraph 2.B. of ASB 05.00.45 R1 or latter approved revision.Note: EASA AD 2006-0101 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. a. Upon accumulating 9,900 flight cycles. Thereafter at intervals not to exceed 55 flight hours.b. At the next ALF-check (after the last flight of the day check) after18 February 2004. Thereafter at intervals not to exceed 55 flight hours.c. At the next ALF-check after 18 February 2004. Thereafter at intervals not to exceed 55 flight hours.2. a. Upon accumulating 7,300 flight cycles. Thereafter at intervals not to exceed 55 flight hours.b. At the next ALF-check after 18 February 2004. Thereafter at intervals not to exceed 55 flight hours.c. At the next ALF-check after 18 February 2004. Thereafter at intervals not to exceed 55 flight hours.The compliance times remain unchanged by this issue of the Directive. |\n|             | This Amendment becomes effective on 5 June 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background: | A crack was discovered on the main gearbox (MGB) base plate of an AS 365 N2 helicopter. The crack was detected in the MGB base plate, close to the attachment of one of the laminated pads, running to the inside of the MGB base plate and then to the MGB casing. Undetected crack growth could lead to the loss of rotor torque-to-structure transfer function.Amendment 1 replaced the previous AOT Requirement documents with ASB Requirement documents, with no change to technical content; and extended the repeat inspection intervals.Amendment 2 is issued to introduce the current EASA AD related to this Directive, which clarifies helicopter applicability; with no change to technical requirements.                           |\n\n|     | The original issue of this Airworthiness Directive became effective on18 February 2004. |\n| --- | --------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n15 April 2008","sortOrder":0},{"sectionNumber":"AD/DAUPHIN/68 Amdt 2","sectionType":"part","heading":"AD/DAUPHIN/68 Amdt 2","content":"## AD/DAUPHIN/68 Amdt 2","sortOrder":1},{"sectionNumber":"Main Gearbox Base Plate","sectionType":"part","heading":"Main Gearbox Base Plate","content":"## Main Gearbox Base Plate","sortOrder":2},{"sectionNumber":"6/2008","sectionType":"part","heading":"6/2008","content":"## 6/2008","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the 2004 directive. Amendment 2 explicitly states it introduces no technical changes — it merely updates cross-references to align with current European Aviation Safety Agency (EASA) documentation and clarifies which helicopter models are covered. The core safety requirement (inspect the main gearbox base plate for cracks) remains unchanged from the original 2004 issue."},"complexity_factors":["Multiple conditional branches based on helicopter model (SA 365 N/N1 vs AS 365 N2/N3)","Nested conditions based on flight cycle count thresholds (9,900 vs 7,300) and overhaul/repair history","Cross-reference to external technical document (Eurocopter ASB 05.00.45 R1) without reproducing its content","Reference to European aviation regulation (EASA AD 2006-0101) for applicability clarification","Technical aviation terminology requiring domain knowledge (flight cycles, ALF-check, MGB, MOD 0763C45)","Amendment structure requiring understanding of version history (Amendment 1 vs Amendment 2 vs original issue)"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specific Eurocopter Dauphin helicopters (SA 365 N/N1 and AS 365 N2/N3) to inspect the main gearbox base plate for cracks and carry out prescribed repairs to prevent gearbox separation and loss of control. It targets gearboxes not modified per Eurocopter Mod 0763C45 and applies based on gearbox history and flight cycles.\n\nThis is Amendment 2 (June 2008), which updates references to align with European standards without changing inspection requirements."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Amendment 2 does not expand the directive’s technical requirements. It aligns the AD wording with the current EASA AD to clarify which helicopter variants are covered. The directive therefore retains its original safety purpose (inspections of MGB base plates) and does not materially grow beyond that scope; it principally clarifies applicability language."},"complexity_factors":["Multiple helicopter variants referenced (SA 365 N, N1, AS 365 N2, N3) with different cycle thresholds","Two distinct flight-cycle trigger values (9,900 and 7,300) depending on variant","Different condition categories: (< threshold, ≥ threshold, newly overhauled/repaired)","Cross-reference to an external technical document: Eurocopter ASB 05.00.45 R1 paragraph 2.B (or later approved revision)","Cross-reference to MOD 0763C45 for applicability (equipment embodiment cutoff)","Compliance timing nuance: some actions tied to 'next ALF-check after 18 February 2004' vs. 'upon accumulating X flight cycles'","Repeating inspections at a non-calendar interval (every 55 flight hours) rather than simpler time- or cycle-based schedule","Reference to external regulator document (EASA AD 2006-0101) for clarification of applicability","Amendment history (original AD, Amdt 1, Amdt 2) requiring readers to check prior changes for context"],"plain_english_summary":"**What this directive does (mechanically)\n\n- Requires regular inspections of the main gearbox (MGB) base plate on certain Eurocopter Dauphin helicopters. The inspections must be carried out in accordance with paragraph 2.B of Eurocopter Alert Service Bulletin (ASB) 05.00.45 R1 (or a later approved revision). (See \"Requirement\" and \"Compliance\".)\n\n**Which helicopters are affected\n\n- All SA 365 N, N1, and AS 365 N2, N3 helicopters, of every serial number, that still have a main gearbox base plate installed that predates embodiment of MOD 0763C45. (See \"Applicability\".)\n\n**When inspections must start and how often\n\n- For SA 365 N and N1: inspections are required on MGBs that have logged 9,900 flight cycles (then repeat at intervals not to exceed every 55 flight hours). Newly overhauled or newly repaired MGBs follow the same inspection action. If the MGB already had 9,900 or more cycles at the relevant compliance milestone, inspection is required at the next ALF check (after-the-last-flight-of-the-day check) after 18 February 2004, then every 55 flight hours. (See \"Requirement\" and \"Compliance\".)\n\n- For AS 365 N2 and N3: the same pattern applies but with the trigger at 7,300 flight cycles (and thereafter every 55 flight hours). Newly overhauled or repaired MGBs follow the same action. If the MGB already had 7,300 or more cycles at the relevant compliance milestone, inspection is required at the next ALF check after 18 February 2004, then every 55 flight hours. (See \"Requirement\" and \"Compliance\".)\n\n**Why this was issued\n\n- A crack was found in the MGB base plate of an AS 365 N2, running from a laminated pad attachment into the MGB casing. Undetected crack growth could break the path that transfers rotor torque into the airframe. The directive references the associated EASA AD and the Eurocopter ASB as the inspection method. (See \"Background\".)\n\n**Who pays and who decides\n\n- Operators/owners of affected helicopters bear the direct costs: scheduling inspections, paying maintenance labour, and any parts or repairs required if a crack or damage is found. \n\n- The operator decides when to schedule maintenance within the compliance windows. Approved maintenance organisations carrying out the inspection must follow ASB 05.00.45 R1 (or later approved revisions). The Civil Aviation Safety Authority (CASA) enforces compliance. (See \"Applicability\", \"Requirement\", \"Compliance\".)\n\n**Immediate and ongoing effects on behaviour and operations\n\n- Operators must track MGB flight cycles and arrange inspections at the stated thresholds (7,300 or 9,900 cycles) and then perform repeat inspections at most every 55 flight hours. \n\n- Maintenance providers must apply the specific ASB inspection procedure (paragraph 2.B) and record compliance. \n\n- If an inspection finds cracking, the operator will need to follow repair/replacement actions specified in the ASB and any approved instructions before returning the helicopter to service. \n\n**Trade-offs, implementation risks and likely costs\n\n- Implementation costs: operator labour and downtime for inspections, potential parts and repair costs, and possible grounding time if a defect is found. The frequency (every 55 flight hours after the threshold) can impose recurring operational disruption for aircraft with high utilisation. (See \"Compliance\".)\n\n- Risk of detection failure: the safety outcome depends on the inspection method’s ability to detect small cracks before they grow; the directive relies on the ASB procedure (paragraph 2.B) for that capability. \n\n- Capacity and scheduling: maintenance facilities must be able to perform the inspections at scale; a sudden discovery of multiple affected aircraft could create a bottleneck for approved repair/overhaul work.\n\n- Regulatory scope: this amendment (Amdt 2) clarifies which helicopter variants are covered consistent with the current EASA AD but states it introduces no change to the technical inspection requirements. The directive therefore does not add new inspection requirements beyond the ones already specified, but it does clarify applicability for operators. (See \"Background\".)\n\n**Relevant textual references in the directive\n\n- Applicability: identifies SA 365 N, N1, AS 365 N2, N3 with MGB base plates prior to MOD 0763C45.\n- Requirement: directs action in accordance with paragraph 2.B of Eurocopter ASB 05.00.45 R1 (or later revision) and sets the flight-cycle thresholds and categories (less than/greater than thresholds; newly overhauled/repaired).\n- Compliance: specifies timing (initial compliance on reaching the flight-cycle threshold or at the next ALF-check after 18 February 2004 for some cases) and repeat interval (not to exceed 55 flight hours).\n- Background: explains the crack discovery and notes that Amdt 2 aligns the AD wording with the EASA AD and clarifies applicability without changing technical content.\n\n**Bottom line**: If you operate an affected Dauphin helicopter with an older MGB base plate, you must follow the Eurocopter ASB inspection procedure at the stated flight‑cycle triggers and then inspect at least every 55 flight hours. The operator pays for inspections and any repairs; CASA enforces compliance. The amendment clarifies which variants are covered but does not change the technical inspection requirements."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate","history":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate/history","analysis":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate/analysis","conflicts":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate/conflicts","importantCases":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate/important-cases","documents":"/api/acts/ad-dauphin-68-amdt-2-main-gearbox-base-plate/documents"}}