Commonwealth legislation

AD/PW4000/4 - Low Pressure Turbine Stage 4 Disk

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

4/10 complexity

This AD requires owners/operators to replace certain Low Pressure Turbine (LPT) Stage 4 disks in Pratt & Whitney PW4000 engines, following the technical steps and timing in FAA AD 99-15-01; it takes effect 7 October 1999.

It affects operators, maintenance organisations and Pratt & Whitney. It responds to a cooling‑hole geometry change that raises disk stress and risk of uncontained failure, shifting compliance costs and technical direction to the FAA requirements and referenced P&W service bulletins.

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AD/PW4000/4 - Low Pressure Turbine Stage 4 Disk

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 Turbine Engines - PW4000 Series

AD/PW4000/4 Low Pressure Turbine Stage 4 Disk 10/99

Applicability: PW4000 series engines with a Low Pressure Turbine (LPT) Stage 4 disk as specified in FAA AD 99-15-01.

Requirement: Replace affected LPT Stage 4 Disks in accordance with the technical requirements of FAA AD 99-15-01.

Note: Pratt and Whitney Service Bulletins PW4ENG 72-657 and PW4G 100-72-105 also refer.

Compliance: At periods detailed in the Requirement document.

This Airworthiness Directive becomes effective on 7 October 1999.

Background: This Directive is prompted by advice that a change in cooling hole geometry on affected LPT disks results in a reduction in cooling air flow to the disk and higher stresses. Higher than normal stress could result in an uncontained disk failure.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/PW4000/4 - Low Pressure Turbine Stage 4 Disk