1AD/PT6A/26 - Power Turbine Containment Ring

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Pratt and Whitney Canada Turbine Engines - PT6A Series

AD/PT6A/26 Power Turbine Containment Ring 10/95

Applicability: All PT6A-11, -11AG, -15AG, -110, -112, -20, -20A, -20B, -21, -25, -25A, -25C, -27,

-28, -34, -34AG, -34B, -36, -114, -116, -135, -135A engines not incorporating an improved power turbine containment ring fitted in accordance with P & WC Service Bulletin No. 12076 Rev. 3 or SB 1427 as applicable.

Requirement: Modify or replace the power turbine containment ring P/N 3022339 in accordance with P & WC Service Bulletin 12076 Rev 3 or SB 1427 as applicable.

Note: AD/PT6A/17 was in issue to require the installation of a P/N 3022339 power turbine containment ring. AD/PT6A/17 has now been cancelled.

Compliance: Effective 14 September 1995: At next engine shop visit that requires the disassembly of any engine flange, but no later than 30 December 1996.

Background: This Directive has been issued to require an improvement to the capability of the engine to contain a power turbine blade release. The improvement is by the replacement or modification of the power turbine containment ring. The requirement follows the investigation of a local PT6A-15AG uncontained power turbine blade release event. In that event, a de-coupling and subsequent overspeed of the power turbine resulted in the release of power turbine blades. The P/N 3022339 ring fitted to that PT6A-15AG failed to contain the released power turbine blades.