AD/ECUREUIL/21 Amdt 1 - Main G/Box Bevel Reduction Gear Module

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Parliament, form the backbone of civil aviation regulation in Australia, addressing various safety and operational standards. One specific legislative instrument, F2006B09334, targets the maintenance and safety of Eurocopter AS 350 (Ecureuil) Series Helicopters, specifically focusing on the main gearbox bevel reduction gear module. This instrument was introduced to address the identified problem of sheared and loose bolts securing the bevel ring gear to the vertical shaft, which had led to safety concerns. The policy objective behind this directive is to ensure the ongoing airworthiness of these helicopters by mandating regular inspections and maintenance checks to prevent such issues. The Civil Aviation Safety Authority has issued Airworthiness Directive AD/ECUREUIL/21 Amendment 1, which outlines a series of checks to be performed at various intervals to ensure the integrity of the bevel reduction gear assembly. The directive requires a visual check within 10 hours of time in service after 31 March 1983 and every 50 hours thereafter, prior to a screw tightening check, which must be carried out once within 300 hours of time in service after 31 March 1983. Following this initial check, further visual checks are mandated every 300 hours. This directive ensures that any potential issues with the bevel reduction gear assembly are identified and rectified in a timely manner, thereby maintaining the safety and reliability of the aircraft in operation.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the Airworthiness Directives for Eurocopter AS 350 (Ecureuil) Series Helicopters, focusing on the maintenance requirements for the main gearbox bevel reduction gear module. This regulation applies to all AS 350 helicopters equipped with a main gearbox containing the bevel reduction gear assembly part numbers 350A32.0300.00, 01 and 02, provided they have not been modified under the specified Aircraft Maintenance Schedules (A.M.S. 07.7082, A.M.S. 07.7083, or A.M.S. 07.7098). The directive mandates specific inspection and maintenance procedures to ensure the safety and airworthiness of these helicopters, as advised by the manufacturer due to previous issues with sheared and loose bolts in the bevel ring gear. The regulation is applicable across the Commonwealth of Australia, enforcing compliance with the detailed inspection schedules outlined in the directive. The directive allows for amendments to the aircraft applicability list through subordinate instruments, as evidenced by the recent inclusion of A.M.S. 07.7098 in the exclusion list.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39, Section 105, mandates specific airworthiness directives for the Eurocopter AS 350 (Ecureuil) Series Helicopters, notably concerning the main gearbox bevel reduction gear module (Section 11/85). This directive applies to all AS 350 helicopters equipped with a main gearbox containing the bevel reduction gear assembly part numbers 350A32.0300.00, 01, and 02, excluding those modified under A.M.S. 07.7082, A.M.S. 07.7083, or A.M.S. 07.7098. The directive requires adherence to AS 350 SB 05.10, Revision 1, and references Bureau Veritas AD 82-176-28(B) for compliance purposes. The directive outlines a series of checks to ensure the integrity and safety of the bevel reduction gear module. Initially, a visual check must be performed within 10 hours of time in service following 31 March 1983, and then every 50 hours prior to the screw tightening check. This visual check is crucial for identifying any potential issues early. After this initial period, a one-time screw tightening check must be carried out within 300 hours of time in service following the specified date. Following the screw tightening check, a visual check must be conducted every 300 hours of time in service thereafter. Operators and maintenance personnel must strictly adhere to these inspection intervals and procedures as outlined in the directive to maintain the airworthiness of the helicopters. Failure to comply with these requirements can result in non-compliance with civil aviation safety standards, potentially leading to aircraft being grounded and significant operational disruptions. The directive’s primary objective is to prevent mechanical failures that could arise from sheared or loose bolts securing the bevel ring gear to the vertical shaft, as highlighted in the manufacturer's advisory. Any breach of these regulations may result in enforcement actions by the Civil Aviation Safety Authority (CASA). The penalties for non-compliance can include fines, operational restrictions, or more severe consequences if the non-compliance is found to contribute to safety risks. Operators must ensure that all inspections and modifications are accurately documented and that all personnel involved are adequately trained to perform these tasks. The safety and operational efficiency of the helicopters depend on strict adherence to these regulatory requirements.