COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/75 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 AS 355 (Twin Ecureuil) Series Helicopters
AD/AS 355/75
Amdt 1
MGB Free-Wheel 4/2004 TX
Applicability: AS 355 E, F, F1, F2 and N model helicopters fitted with a combiner gearbox pre- MOD 077212 that has less than 10 flying hours since new, or since overhaul or since repair.
Requirement: Replace the free wheel rollers in the combiner gearbox as detailed in Eurocopter Alert Telex No. 63.00.21 R2
Note: DGAC Telex AD UF-2004-021 refers.
Compliance: Prior to further flight
This Amendment becomes effective on 26 February 2004.
Background: This amendment is in response to the manufacturer now identifying that the problem of slippage is not caused by insufficient cleaning of preservation fluid, but due to a change in the process that is applied to the free wheel rollers. The change from the “Bonderite” to “Parcolubrite” process has not provided the free wheel adherence in the first few hours of operations. Subsequently the applicability and the requirements now detailed are to address the cause of the problem.
This directive was issued to address a report of an engine overspeed event involving an AS355 helicopter during the single engine phase of an acceptance flight. The engine overspeed resulted from free-wheel clutch slippage was originally believed to be due to insufficient cleaning of preservation fluid from the main gearbox.
The original issue of this Directive became effective 21 January 2004.
James Coyne
Delegate of the Civil Aviation Safety Authority 23 February 2004
The above AD is notified in the Commonwealth of Australia Gazette on 26 February 2004.
Overview
The Civil Aviation Safety Regulations 1998, enacted by the Commonwealth of Australia, were established to ensure the safe operation of civil aviation within Australia. This legislation, overseen by the Civil Aviation Safety Authority (CASA), was introduced to fill a critical gap in ensuring the safety and reliability of civil aircraft and aeronautical products. One specific aspect of these regulations is the issuance of Airworthiness Directives (ADs) which are used to address safety concerns in specific aircraft models. An example of such an AD is the amendment to AD/AS 355/75 for Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, issued on 26 February 2004. This amendment aimed to address an engine overspeed event caused by free-wheel clutch slippage, originally attributed to insufficient cleaning of preservation fluid. The AD required the replacement of free wheel rollers in the combiner gearbox for specific models of the Eurocopter AS 355 series, reflecting the policy objective of mitigating safety risks through targeted corrective actions.
Scope and Application
The Civil Aviation Safety Regulations 1998, specifically under PART 39 - 105 and the Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all operators of Eurocopter AS 355 (Twin Ecureuil) Series Helicopters fitted with a combiner gearbox pre-MOD 077212 that have less than 10 flying hours since new, since overhaul, or since repair. This legislative instrument is applicable nationally across the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority (CASA). The Airworthiness Directive mandates that operators must replace the free wheel rollers in the combiner gearbox as specified in Eurocopter Alert Telex No. 63.00.21 R2. This requirement must be completed prior to further flight and the directive came into effect on 26 February 2004. The directive responds to an identified issue of free-wheel clutch slippage, originally thought to be due to insufficient cleaning of preservation fluid, but later found to be caused by a change in the process applied to the free wheel rollers.
Key Provisions
The Civil Aviation Safety Regulations 1998, specifically Part 39, Section 105, outlines the requirements for Airworthiness Directives (ADs) issued by the Civil Aviation Safety Authority (CASA). An AD is a regulatory mandate issued to ensure the safety of aircraft or aeronautical products by mandating corrective actions to address unsafe conditions. In this instance, the AD (AD/AS 355/75) has been revoked and replaced with a new directive concerning Eurocopter AS 355 (Twin Ecureuil) series helicopters. The new directive mandates the replacement of free wheel rollers in the combiner gearbox for certain models of these helicopters under specific conditions (section 105(1)). The AD requires that this action be taken when the aircraft meet the criteria outlined in the applicability section, adhering to the instructions in the requirement section, and before further flights as stated in the compliance section.
Operators of AS 355 E, F, F1, F2, and N model helicopters that are fitted with a combiner gearbox pre-MOD 077212 and have less than 10 flying hours since new, since overhaul, or since repair, must comply with the new AD. Specifically, these operators are required to replace the free wheel rollers in the combiner gearbox as detailed in Eurocopter Alert Telex No. 63.00.21 R2. This directive aims to correct an identified issue of free-wheel clutch slippage, which was previously misdiagnosed as a preservation fluid cleaning issue, but is now understood to be due to a change in the manufacturing process of the free wheel rollers.
Failure to comply with the AD may result in serious safety implications, including potential engine overspeed events during flight, which can lead to catastrophic outcomes. While the legislation itself does not explicitly state penalties for non-compliance, non-compliance with CASA directives can lead to enforcement actions by CASA, including fines, grounding of the aircraft, or other administrative penalties under the Civil Aviation Act 1988 and related regulations. CASA has the authority to take legal action to ensure compliance with safety directives to protect the public and maintain the integrity of the aviation system.