AD/GBK 117/10 - Introduction of a Life Limit on Tail Rotor Drive Bevel Gear

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, address various safety standards and requirements in the aviation sector. One such regulation, found in Part 39 - 105, pertains to airworthiness directives for specific aircraft models. The regulation introduces a life limit on the tail rotor drive bevel gear for Eurocopter BK 117 Series Helicopters, particularly those with serial numbers ranging from 7001 to 7250 and 7500 to 7509. The policy objective behind this regulation is to ensure the safety and reliability of these helicopters by imposing a life limitation on a critical component, thus preventing potential failures that could compromise flight safety. Compliance with this directive is mandatory and must be achieved by 31 March 1998, with the directive taking effect from 26 February 1998.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the application of airworthiness directives issued by the Civil Aviation Safety Authority, and in this instance, addresses the Eurocopter BK 117 Series Helicopters. The regulation applies to Eurocopter MBB-BK 117 helicopters with serial numbers ranging from 7001 to 7250 inclusive, and from 7500 to 7509 inclusive. This directive mandates the introduction of a life limit of 18,500 hours on the tail rotor drive bevel gear, part number 117-12215-01, which is part of the main transmission. The requirement involves recording this life limitation in the Accessory Replacement Record and Historical Record "Main Transmission". For compliance, it is essential to know the total operating time of the bevel gear; if this is unknown, the total operating time of the main transmission should be considered. The directive references LBA AD 97-350 dated 18 December 1997 and stipulates that compliance action must be completed by 31 March 1998, with the directive becoming effective from 26 February 1998. This directive is an essential measure to ensure the continued safety of the specified Eurocopter BK 117 Series Helicopters in Australian airspace.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, introduce a life limit on the tail rotor drive bevel gear for Eurocopter BK 117 Series Helicopters through Airworthiness Directive (AD/GBK 117/10). This directive applies to Eurocopter MBB-BK 117 helicopters with Serial Numbers (S/N) ranging from 7001 to 7250 inclusive, and from 7500 to 7509 inclusive (Section 3/98). The directive requires the imposition of a life limitation of 18,500 hours on Bevel Gear 117-12215-01, which is the tail rotor output drive unit of the main transmission. This limit must be recorded in both the Accessory Replacement Record and the Historical Record under the “Main Transmission” section. To determine the replacement time for the installed bevel gear, the total operating time of the component must be known. If the specific operating time of the bevel gear is unknown, it is to be considered as equivalent to the operating time of the entire main transmission. Operators and maintenance personnel of the affected helicopters must adhere to the requirements set out in this directive. Specifically, they must ensure that the life limit of 18,500 hours is documented appropriately and that the bevel gear is replaced or inspected as necessary to meet this limit. The directive references LBA AD 97-350 dated 18 December 1997, indicating that this directive builds on previous guidance. Compliance with this directive is mandatory, and the required actions must be completed by 31 March 1998. The directive itself became effective on 26 February 1998. Failure to comply with the provisions of this airworthiness directive can have serious consequences. Although the specific penalties are not detailed in the provided text, non-compliance with airworthiness directives generally can result in substantial penalties under the Civil Aviation Act 1988. These penalties can include fines, imprisonment, or both, depending on the severity of the breach and the circumstances of the non-compliance. In addition to criminal and civil penalties, non-compliance can also lead to operational restrictions, including grounding of the aircraft until compliance is achieved, which can have significant financial and logistical impacts on operators.