AD/BELL 412/36 - Main Rotor Mast

Overview

The Civil Aviation Regulations 1998, under Part 39 - 105, incorporates a legislative instrument (F2006B04670) designed to address the safety concerns associated with the main rotor mast and spline plate of Bell Helicopter Textron 412 Series Helicopters. This legislation was enacted by the Commonwealth of Australia to ensure the airworthiness of the specified helicopter models, thereby mitigating risks associated with the structural integrity of the main rotor mast and spline plate. The objective is to mandate compliance with the manufacturer's updated procedures for determining the retirement life of these critical components, ensuring that they do not exceed their designated operational hours or maximum Retirement Index Numbers, thus maintaining safety standards in civil aviation. The policy objective behind this legislative instrument is to enhance aviation safety by ensuring that the main rotor mast and spline plate of Bell 412 Series Helicopters are regularly inspected and maintained according to the manufacturer's specifications. This directive is essential for preventing potential failures that could lead to catastrophic outcomes. The compliance requirement stipulates that the action must be taken within 100 hours of the helicopter's time in service from 27 April 1995 or by 27 August 1995, whichever comes first, ensuring timely and effective implementation of safety measures.

Scope and Application

The Civil Aviation Regulations 1998, as detailed in PART 39 - 105, mandate specific requirements for the airworthiness of Bell Helicopter Textron 412 Series helicopters equipped with designated main rotor masts and spline plates. This regulation applies to all model 412 series helicopters with particular parts numbers, and it necessitates compliance with Bell Alert Service Bulletin 412-94-81 Revision A. Operators must ensure that the specified maintenance action is carried out within 100 hours of the helicopter's time in service from 27 April 1995 or by 27 August 1995, whichever comes first. These directives are established to ensure the ongoing safety and airworthiness of the aircraft, and failure to comply can result in significant legal and safety repercussions. The scope of the regulation is explicitly limited to the specified helicopter models and components, ensuring that the requirements are targeted and precise.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 105, mandate specific requirements for the airworthiness of Bell Helicopter Textron 412 series helicopters. Section AD/BELL 412/36 focuses on the main rotor mast and associated components, particularly those with specified part numbers (s. 1). The directive requires that the actions outlined in Bell Alert Service Bulletin 412-94-81 Revision A be undertaken, ensuring compliance within 100 hours of time in service from 27 April 1995 or by 27 August 1995, whichever comes first (s. 2). These actions pertain to the revised procedures for determining the retirement life of the main rotor mast and spline plate, which now have a retirement life of 10,000 hours or 80,000 maximum Retirement Index Numbers (RIN) for certain models, and 10,000 hours or 60,000 RIN for others (s. 3). Operators and owners of the specified Bell Helicopter Textron 412 series must adhere to the requirements set out in the Alert Service Bulletin. This includes conducting the necessary inspections, maintenance, or replacements as per the updated procedures to ensure the continued airworthiness of the helicopters. They must ensure that the helicopters fitted with the particular main rotor mast and spline plate part numbers comply with the stipulated retirement life (s. 4). Non-compliance with these directives could potentially lead to safety issues, rendering the aircraft non-airworthy and putting it out of operation until the necessary actions are taken. Failure to comply with these provisions can result in serious consequences. The Civil Aviation Safety Authority (CASA) can impose penalties on operators and owners who do not adhere to the Airworthiness Directives. Such penalties may include fines, suspension or revocation of the operator's certificate, or even criminal charges in cases of gross negligence or wilful default (s. 5). The specific penalties are determined by CASA and can vary based on the severity and circumstances of the non-compliance. It is crucial for operators and owners to follow these directives to maintain the safety and airworthiness of their aircraft.