{"id":"F2006B08770","name":"AD/DAUPHIN/58 Amdt 1 - Main Gearbox Torque Tightening","slug":"ad-dauphin-58-amdt-1-main-gearbox-torque-tightening","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52087,"registerId":"commonwealth-F2006B08770-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DAUPHIN/58 Amdt 1 - Main Gearbox Torque Tightening","content":"![](image.001.png)\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/DAUPHIN/58 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nEurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\nAD/DAUPHIN/58\n\nAmdt 1\n\n  \nMain Gearbox Torque Tightening 9/2003\n\nApplicability: AS 365 helicopters versions N, N1, N2 and N3 fitted with Main GearBox (MGB) P/N 365 A 32.6000.00/02, or 365 A 32.6001.00/01; and modified to MOD 0763B79 (new O-ring seals) but not modified per MOD 0763B76 (new reinforced attachment studs);\n\nand\n\nSA 365 helicopters versions C, C1, C2 and C3 fitted with Main Gearbox P/N 365 A 32.4000.02/03/05, and modified to MOD 0763B79 (new O-ring seals) but not modified per MOD 0763B76 (new reinforced attachment studs).\n\nRequirement: Carry out re-torque of the MGB in accordance with the Accomplishment Instructions of Eurocopter Alert Service Bulletin (ASB) No. 05.00.42 or 05.23 as applicable.\n\nNote: DGAC AD 2002-283-048(A) R1 and DGAC AD 2002-285-055(A) R1 refer.\n\nCompliance: 1. Unless previously accomplished for MGB’s that have logged less than 500 flight hours since last overhaul, no later than 550 hours Time in Service (TIS).\n\n    2. Unless previously accomplished for MGB that have logged more than 500 flight hours since last overhaul, within 50 hours TIS from when this Directive becomes effective.\n\n    3. Repeat at intervals of not more than 550 flight hours. This Amendment becomes effective on 4 September 2003.\n\nBackground: This Amendment reflects changes in the reference documentation.\n\nLoosening of the main gearbox studs is a problem with the MGB, but oil leakage showed that the MGB studs were failing and gave sufficient warning for the problem to be addressed. MOD 0763B79 was introduced to improve the sealing of the MGB. Operators that chose to incorporate MOD 0763B79 without including MOD 0763B76, which improved the stud installation, have found that stud failure is no longer indicated by oil leakage. Failure to not address loosening of the studs could lead to MGB failure. This Directive addresses this problem by introducing a repetitive inspection of the stud torque.\n\nEurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\nAD/DAUPHIN/58 Amdt 1 (continued)\n\nThe original issues of this Directive became effective on 8 August 2002.\n\n![Signature of Jim Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 25 July 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 13 August 2003.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) that explicitly states it only 'reflects changes in the reference documentation.' The substantive safety requirement — re-torquing the main gearbox studs on affected helicopters — remains identical to the original August 2002 directive. The scope has not expanded beyond the original safety intent."},"complexity_factors":["Multiple applicability conditions requiring cross-checking of part numbers (P/N 365 A 32.6000.00/02, etc.) and modification status (MOD 0763B79 vs MOD 0763B76)","Tiered compliance deadlines based on flight hours since overhaul (500-hour threshold creates two different compliance paths)","Repetitive inspection requirement (ongoing obligation every 550 hours, not one-off)","Reference to external technical documents (Eurocopter Alert Service Bulletin 05.00.42 or 05.23) without reproducing their content","Cross-reference to French aviation safety directives (DGAC AD 2002-283-048(A) R1 and DGAC AD 2002-285-055(A) R1)"],"plain_english_summary":"This CASA safety order targets Eurocopter Dauphin AS365/SA365 helicopters that have had seal upgrade MOD 0763B79 but not the stronger-bolt MOD 0763B76. Improved seals can hide loosening main gearbox attachment studs, creating a risk of sudden, catastrophic gearbox failure without visible oil leaks.\n\nOperators must re-torque the main gearbox studs per Eurocopter service instructions within specified flight-hour windows (and every 550 FH thereafter). The measure prevents in‑flight gearbox detachment and potential fatal crashes."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Amendment does not expand or narrow the AD's substantive scope. It retains the same applicability (specific SA360/SA365 helicopters with particular MGB P/Ns and modification combinations), the same required action (re-torque per the Eurocopter ASB) and the same repetitive interval (550 flight hours). The Amendment primarily updates reference documentation and official issuance details without altering the core obligations or affected fleet."},"complexity_factors":["Technical specificity: exact helicopter models, MGB part numbers and retrofit modification status (MOD 0763B79 vs MOD 0763B76) required to determine applicability.","Conditional compliance windows: different initial deadlines depending on whether the MGB has logged more or less than 500 flight hours since last overhaul.","Repetitive maintenance requirement: ongoing 550-hour re-torque intervals create recurring operational and scheduling burdens.","Reference to external technical documents: mandatory reliance on Eurocopter Alert Service Bulletins (ASB Nos. 05.00.42 or 05.23) for procedures.","Regulatory action replaces a prior AD: the instrument revokes and reissues a prior directive, requiring operators to track amendment effective dates.","Operational impact: inspections require qualified maintenance personnel and induce aircraft downtime, affecting availability and cost."],"plain_english_summary":"This Airworthiness Directive requires operators of certain Eurocopter SA360/SA365 (Dauphin) helicopters — those with specified main gearbox (MGB) part numbers that have MOD 0763B79 but not MOD 0763B76 — to perform an initial re‑torque of the MGB attachment studs and then repeat the torque check every 550 flight hours, following the Eurocopter Alert Service Bulletin. The change responds to a sealing modification that can hide stud loosening which previously showed by oil leakage.\n\nOperators pay for the inspections, parts and downtime; the CASA delegate sets timing and method by referencing the ASB, and compliance timing depends on hours since last overhaul."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening","history":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening/history","analysis":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening/analysis","conflicts":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening/conflicts","importantCases":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening/important-cases","documents":"/api/acts/ad-dauphin-58-amdt-1-main-gearbox-torque-tightening/documents"}}