AD/ECUREUIL/46 - Tail Rotor Drive Shaft Bearings

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, represent a comprehensive framework designed to ensure the safety and efficiency of civil aviation within Australia. This legislation, particularly Part 39, addresses a critical gap by establishing stringent safety standards and directives for the maintenance and operation of aircraft. One such directive, AD/ECUREUIL/46, specifically targets the tail rotor drive shaft bearings of Eurocopter AS 350 (Ecureuil) Series helicopters. The directive aims to mitigate the risk of corrosion and potential seizure of these critical components, thereby ensuring the continued airworthiness of the affected aircraft models. This regulation underscores the Civil Aviation Safety Authority's commitment to maintaining high safety standards in civil aviation, aiming to prevent mechanical failures that could compromise flight safety. The directive was introduced by the Civil Aviation Safety Authority, reflecting a policy objective to address identified safety risks associated with specific aircraft components. The requirement for compliance with the Technical Requirements of DGAC AD 91-159-060 (B) for certain AS 350 helicopter models is a proactive measure to ensure that all affected aircraft are inspected and maintained according to the specified criteria. The urgency for compliance by 30 August 1991 or prior to the issue of an Australian Certificate of Airworthiness highlights the importance placed on timely and effective action to safeguard against potential mechanical failures.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, applies to all AS 350 helicopters of versions B, D, B1, B2, L1 and AVEX that are equipped with P/N P.9107.NPP7 FAFNIR tail rotor drive shaft bearings, excluding those marked with an "X" on the seal flange. This legislation is issued by the Civil Aviation Safety Authority and pertains to the maintenance and safety requirements of these particular aircraft. The regulations have a Commonwealth reach, ensuring compliance across the entirety of Australia. The requirement mandates actions as per the Technical Requirements of DGAC AD 91-159-060 (B) for all aircraft that were acceptance tested by Aerospatiale Marignane between 15 May 1991 and 20 July 1991 or were tested prior to 15 May 1991 and have operated for less than 100 hours in service. Compliance must be achieved by 30 August 1991 or before the issue of an Australian Certificate of Airworthiness, whichever comes first. The regulations also provide a reference to Aerospatiale Telex Service No. 01-34 for further details on the issue.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 105 and the Airworthiness Directives (AD), include a specific directive for Eurocopter AS 350 (Ecureuil) Series Helicopters, identified as AD/ECUREUIL/46 (1). This directive pertains to the tail rotor drive shaft bearings of certain AS 350 models, specifically those versions B, D, B1, B2, L1, and AVEX equipped with a P/N P.9107.NPP7 FAFNIR tail rotor drive shaft bearing not marked with an “X” on the seal flange. The directive mandates compliance with the Technical Requirements outlined in DGAC AD 91-15-9-060 (B), which applies to helicopters that were acceptance tested by Aerospatiale Marignane between 15 May 1991 and 20 July 1991 or had been tested prior to 15 May 1991 and have operated for less than 100 hours in service (2). The obligations imposed by AD/ECUREUIL/46 require that affected helicopters be inspected and any necessary actions taken in accordance with the specified technical requirements. This includes the inspection and potentially the replacement of the tail rotor drive shaft bearings to mitigate the risk of corrosion and seizure. Compliance with these directives must be achieved by 30 August 1991 or before the issue of the Australian Certificate of Airworthiness (C of A), whichever comes first (3). Additionally, operators of these helicopters must ensure that any modifications or inspections are documented and that the aircraft is deemed airworthy before further operation. Failure to comply with the provisions of AD/ECUREUIL/46 can result in significant consequences. The Civil Aviation Safety Authority (CASA) can enforce civil penalties for non-compliance, which can include fines up to the statutory maximum. In more severe cases, continued operation of a non-compliant aircraft can lead to criminal charges and imprisonment for individuals responsible for the aircraft's maintenance and operation. These measures are in place to ensure the safety of air travel and to prevent potential hazards associated with the identified issue in the tail rotor drive shaft bearings (4).