AIRWORTHINESS DIRECTIVE
For 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.
Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters
AD/DAUPHIN/58
Amdt 1
Main Gearbox Torque Tightening 9/2003
Applicability: 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);
and
SA 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).
Requirement: 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.
Note: DGAC AD 2002-283-048(A) R1 and DGAC AD 2002-285-055(A) R1 refer.
Compliance: 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).
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.
3. Repeat at intervals of not more than 550 flight hours. This Amendment becomes effective on 4 September 2003.
Background: This Amendment reflects changes in the reference documentation.
Loosening 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.
Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters
AD/DAUPHIN/58 Amdt 1 (continued)
The original issues of this Directive became effective on 8 August 2002.
Jim Coyne
Delegate of the Civil Aviation Safety Authority 25 July 2003
The above AD is notified in the Commonwealth of Australia Gazette on 13 August 2003.
Overview
The Civil Aviation Safety Authority Act 1998 (CASA Act) was enacted to ensure the safety of civil aviation in Australia by regulating air navigation, aircraft operations, and the airworthiness of aircraft. The Act established the Civil Aviation Safety Authority (CASA), which is responsible for ensuring compliance with aviation safety regulations and issuing directives to address safety concerns. One such directive is the Airworthiness Directive (AD) AD/DAUPHIN/58 Amdt 1, issued under the authority of the CASA Act to address the specific issue of main gearbox stud loosening in certain Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters. The AD mandates the re-torqueing of the main gearbox in accordance with specified instructions to mitigate the risk of stud failure and subsequent gearbox failure, thereby ensuring the continued airworthiness of affected helicopters. This AD was introduced to address the problem of main gearbox stud loosening, which can lead to gearbox failure if not properly managed. By requiring the re-torqueing of the gearbox, the directive aims to maintain the structural integrity of the gearbox and prevent potential in-flight failures.
Scope and Application
The Airworthiness Directive (AD) AD/DAUPHIN/58 Amdt 1 issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998 pertains to specific Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters, applying to AS 365 helicopters versions N, N1, N2, and N3, and SA 365 helicopters versions C, C1, C2, and C3, each fitted with a specific Main GearBox (MGB) part number and modified to MOD 0763B79, but not MOD 0763B76. This directive applies to any person or entity operating these aircraft within the Commonwealth of Australia, necessitating adherence to the requirements outlined. The directive mandates that the re-torque of the MGB be carried out in accordance with Eurocopter Alert Service Bulletin (ASB) No. 05.00.42 or 05.23 as applicable. The compliance schedule requires that re-torque be completed within 50 hours Time in Service (TIS) for MGBs that have logged more than 500 flight hours since the last overhaul, and no later than 550 hours TIS for those with less than 500 flight hours. The directive repeats at intervals of not more than 550 flight hours. This AD does not include any stated exclusions or exemptions but extends its application through subordinate instruments as necessary.
Key Provisions
The Airworthiness Directive (AD) AD/DAUPHIN/58 Amdt 1, issued by the Civil Aviation Safety Authority (CASA) delegate, applies to specific models of Eurocopter SA 360 and SA 365 (Dauphin) Series helicopters, namely versions N, N1, N2, N3, C, C1, C2, and C3. The AD mandates that these helicopters must have their main gearbox (MGB) re-torqued according to the Accomplishment Instructions provided in Eurocopter Alert Service Bulletin (ASB) No. 05.00.42 or 05.23, depending on the applicable version (section 1). This re-torqueing is a crucial action to address the issue of loosening MGB studs, which can lead to MGB failure if not properly managed.
Operators of the specified helicopters must ensure that the re-torqueing of the MGB is carried out in accordance with the AD's requirements and within the stipulated timeframes (section 2). For MGBs that have accumulated less than 500 flight hours since their last overhaul, the re-torqueing must be performed no later than 550 hours of Time in Service (TIS). For MGBs with more than 500 flight hours since the last overhaul, the re-torqueing must occur within 50 hours TIS from the date the AD becomes effective. Furthermore, this process must be repeated at intervals of not more than 550 flight hours thereafter.
Failure to comply with the AD's requirements can result in severe consequences. Specifically, operators who do not adhere to the mandated re-torqueing schedule may face enforcement actions, which can include fines, penalties, or other civil and criminal consequences as prescribed by relevant aviation regulations. The AD underscores the critical nature of maintaining the correct torque on the MGB studs to prevent potential failures that could compromise the airworthiness of the helicopters. Operators are, therefore, legally obligated to ensure strict compliance with the AD to maintain safety standards and prevent any unsafe conditions that could endanger flight operations.