AD/BELL 212/35 - Tail Rotor Trunnion Bearing Housing

Overview

The Civil Aviation Regulations 1998, amended in 2006, was enacted by the Commonwealth of Australia to ensure the safety and regulation of civil aviation activities within the country. The specific legislative instrument referenced here, F2006B04566, focuses on the issuance of an Airworthiness Directive (AD) concerning the tail rotor trunnion bearing housing of the Bell Helicopter Textron 212 Series Helicopters. This directive was introduced to address a critical safety issue where the trunnion bearing housing end web had been found to be below the specified dimensions, which could result in excessive tail rotor vibration and a potential loss of control. The AD mandates compliance with Bell Alert Service Bulletin No. 212-86-39, Revision A, to ensure the safety of the aircraft and its occupants by setting forth specific time intervals for inspection and maintenance of the affected components. The policy objective of this legislative instrument is to mitigate the risks associated with the identified safety defect by requiring timely inspections and necessary actions to be taken by the aircraft operators. The directive applies to all Bell Helicopter Textron 212 Series Helicopters within specified serial number ranges, ensuring that these safety measures are uniformly implemented across the relevant fleet. This proactive approach by the Civil Aviation Safety Authority aims to prevent accidents and enhance the overall safety standards of civil aviation in Australia.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority's schedule of airworthiness directives, applies to all Bell Helicopter Textron 212 Series Helicopters with serial numbers falling within specified ranges, namely 30501 to 30999, 31101 to 31273 and 31275, 32101 to 32142, and 32201 to 32262. This legislation mandates compliance with Bell Alert Service Bulletin No. 212-86-39, Revision A, concerning the tail rotor trunnion bearing housing. Compliance requires action in two parts: the first part must be completed within 25 hours of time in service or seven days after 6 August 1986, and thereafter at intervals not exceeding 25 hours time in service or seven days, whichever occurs first, until the second part is addressed. The second part must be completed within 150 hours of time in service or 60 days after 31 July 1986. This directive arises from findings that a trunnion bearing housing end web was below specified dimensions, which if failed, could result in excessive tail rotor vibration and loss of control. This regulation applies nationally within Australia, overseen by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, mandate specific safety directives for the Bell Helicopter Textron 212 Series Helicopters, specifically concerning the tail rotor trunnion bearing housing. The relevant directive, AD/BELL 212/35, applies to all model 212 helicopters with serial numbers ranging from 30501 to 30999, 31101 to 31273 and 31275, 32101 to 32142, and 32201 to 32262. The directive stipulates that these aircraft must adhere to the requirements outlined in Bell Alert Service Bulletin No. 212-86-39, Revision A. This bulletin provides detailed instructions on the necessary actions to be taken to ensure the airworthiness of the helicopters in question. The compliance requirements are stringent and involve two distinct phases. For Part I, operators must conduct inspections and actions within 25 hours of time in service or within seven days, whichever comes first, after the directive was issued on 6 August 1986. This initial phase must be followed by subsequent inspections and actions at intervals not exceeding 25 hours of time in service or seven days, again whichever comes first, until Part II of the requirement is fulfilled. Part II necessitates compliance within 150 hours of time in service or within 60 days, whichever comes first, after 31 July 1986. These timelines are crucial to maintaining the operational safety of the helicopters. Operators and owners of the affected Bell Helicopter Textron 212 Series must adhere to the strict compliance schedules outlined in the directive. This includes conducting timely inspections and taking corrective actions as specified in the Bell Alert Service Bulletin. Failure to comply with these requirements can result in serious safety hazards, including the risk of tail rotor vibration and loss of control, which has been documented as a consequence of trunnion bearing housing failure. Ensuring that the bearing housing end web meets the specified dimensions is essential to prevent such failures. Non-compliance with the AD/BELL 212/35 directive can result in significant legal and safety repercussions. The Civil Aviation Safety Authority (CASA) has the authority to impose penalties for breaches of these regulations. Offences related to non-compliance can lead to both civil and criminal consequences. Civil penalties may include fines, while criminal penalties can result in imprisonment. The exact penalties are determined by the severity of the breach and the potential risk to aviation safety. Operators and owners are thus legally obligated to ensure that their helicopters meet the requirements of the directive to avoid these severe consequences.