AD/PT6A/26 - Power Turbine Containment Ring

Overview

The Civil Aviation Regulations 1998, which were enacted by the Parliament of the Commonwealth of Australia, aim to ensure the safety of civil aviation. One of the legislative instruments issued under this act is F2006B06363, which addresses the problem of uncontained power turbine blade releases in Pratt and Whitney Canada PT6A series turbine engines. This was introduced in response to an incident where a PT6A-15AG engine's power turbine containment ring failed to contain the released blades, leading to potential hazards. The policy objective is to enhance the capability of the engine to contain such releases, thereby improving overall aviation safety. Compliance with these airworthiness directives is mandatory, with specific timelines set for the modification or replacement of the power turbine containment rings to mitigate risks.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 106 Civil Aviation Safety Authority Schedule of Airworthiness Directives, mandate certain safety measures for Pratt and Whitney Canada's PT6A Series turbine engines, particularly regarding the power turbine containment ring. This regulation applies to a comprehensive list of PT6A engines, excluding those that have already been fitted with an improved power turbine containment ring according to Pratt & Whitney Canada Service Bulletins No. 12076 Rev. 3 or SB 1427 as applicable. The directive requires that the power turbine containment ring P/N 3022339 be modified or replaced to enhance the engine's capability to contain a power turbine blade release, following an incident where the P/N 3022339 ring failed to contain blades in a PT6A-15AG engine. Compliance with this directive is mandatory for the specified engines and must be achieved at the next engine shop visit requiring flange disassembly, but no later than 30 December 1996. The regulation applies across the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority, and extends to any entities operating aircraft equipped with the specified engines.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39, specifically Section 106, includes Airworthiness Directives that govern the maintenance and modification of certain aircraft components. One such directive, AD/PT6A/26, concerns Pratt and Whitney Canada Turbine Engines of the PT6A Series, focusing on the power turbine containment ring (Section 106). This directive applies to all PT6A engines listed in the applicability clause, excluding those that have already been fitted with an improved power turbine containment ring according to Pratt & Whitney Canada (P&WC) Service Bulletins 12076 Rev. 3 or SB 1427 (Section 106). The requirement of this directive is to modify or replace the power turbine containment ring part number 3022339, in accordance with the specified service bulletins (Section 106). Compliance with this directive is mandatory and must be achieved at the next engine shop visit that necessitates the disassembly of any engine flange, but no later than 30 December 1996 (Section 106). This directive has been issued following an investigation into an uncontained power turbine blade release event in a PT6A-15AG engine, where the original containment ring failed to prevent the release of power turbine blades (Section 106). The obligations imposed by this directive require that the affected engines be inspected and, if necessary, modified or replaced with the specified containment ring. This action is essential to enhance the engine's capability to contain a power turbine blade release, thus improving overall aircraft safety (Section 106). Failure to comply with this directive could result in non-compliance with the Civil Aviation Regulations, potentially leading to severe civil or criminal consequences. The specific penalties for non-compliance are not detailed in the directive itself but could include fines or other enforcement actions under the broader Civil Aviation Act 1988 or subsequent regulations (Section 106).