AD/S-76/58 - Tail Gearbox Output Shaft

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, serve to regulate and ensure the safety of civil aviation within the country. One particular legislative instrument under this act, F2006B06733, addresses a specific safety concern for Sikorsky S-76 Series Helicopters, particularly models S76A, S76B, and S76C up to serial number 760390. This directive, known as AD/S-76/58, was introduced to mitigate the risk of premature fatigue failure caused by a surface irregularity or groove in the tail rotor gearbox output shaft assembly internal bore. The policy objective is to ensure that all specified helicopters undergo a mandatory inspection within 150 hours of time in service from 30 April 1992 or by 30 August 1992, whichever comes first, in accordance with the Sikorsky Alert Service Bulletin No 76-66-27. This requirement aims to enhance the overall safety and reliability of the affected helicopter fleet by addressing potential mechanical issues that could compromise flight safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, which outlines the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, applies to all Sikorsky S-76 series helicopters, namely the S76A, S76B, and S76C models, up to and including serial number 760390. The legislation mandates compliance with Sikorsky Alert Service Bulletin No 76-66-27, which involves a one-time inspection of the tail rotor gearbox output shaft assembly internal bore for any surface irregularities or grooves. This requirement is designed to prevent premature fatigue failure in the specified helicopters. The compliance period is set within 150 hours of time in service from 30 April 1992, or by 30 August 1992, whichever comes first. This regulation applies across the Commonwealth of Australia, as stipulated by the Civil Aviation Safety Authority, and is intended to ensure the airworthiness and safety of these aircraft. The regulations do not explicitly exclude any entities or individuals from their scope and are enforced nationally within Australia's jurisdiction.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, outlines the regulatory requirements for the Sikorsky S-76 Series Helicopters, notably in AD/S-76/58. This directive applies to all model S76A, S76B, and S76C helicopters up to and including serial number 760390. The key requirement (Section 39 - 105) mandates that the tail gearbox output shaft must be inspected in accordance with Sikorsky Alert Service Bulletin No 76-66-27. This inspection is necessary to identify any surface irregularities or grooves within the internal bore of the tail rotor gearbox output shaft assembly. Such irregularities could potentially lead to premature fatigue failure, which poses a significant safety risk. Operators of the affected Sikorsky S-76 Series helicopters must comply with the directive by ensuring that the required inspection is performed within 150 hours of time in service from 30 April 1992, or by 30 August 1992, whichever occurs first. This timeframe is crucial to maintain the airworthiness and safety of the aircraft. Compliance involves following the detailed procedure outlined in the Sikorsky Alert Service Bulletin, which likely includes specific steps for inspecting and, if necessary, rectifying any identified issues. Failure to adhere to the requirements set forth in AD/S-76/58 could result in severe consequences. The Civil Aviation Regulations 1998 impose strict obligations on the operators and owners of the affected helicopters to ensure compliance with the directive. Non-compliance could lead to the aircraft being deemed unairworthy, which would prevent its operation until the required actions are completed and approved by CASA. In addition to the operational risks, operators may face significant legal and financial penalties. The exact penalties are not specified within the text of the directive but could include fines, operational restrictions, or even the revocation of the aircraft's certificate of airworthiness under the broader regulatory framework. Given the potential safety implications, the penalties for non-compliance with AD/S-76/58 could also include criminal charges if the failure to comply is deemed to have caused or contributed to an aviation accident or incident. The severity of the penalties underscores the importance of adhering to the directive's requirements to ensure the continued safety and airworthiness of the Sikorsky S-76 Series helicopters.