Commonwealth legislation

AD/PW4000/2 - 2nd Stage HPT Rotating Airseal

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legislative instrument

Plain English Summary

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Requires operators of Pratt & Whitney PW4000 engines to inspect the 2nd‑stage high‑pressure turbine (HPT) rotating airseal using specified Pratt & Whitney service bulletins, and to modify ring segments/vane clusters and fit improved rotating seals. Inspections must occur whenever the HPT is disassembled and the mod must be completed within six years; the mod ends the inspection requirement. The directive is prompted by reported airseal cracking that could cause uncontained engine failure. Costs and scheduling fall to engine operators, who must follow the referenced service bulletins.

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AD/PW4000/2 - 2nd Stage HPT Rotating Airseal

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/PW4000/2 2nd Stage HPT Rotating Airseal 1/99

Applicability: PW4000 series engines.

Requirement: 1. Inspect 2nd stage high pressure turbine rotating airseals in accordance with Pratt and Whitney Alert Service Bulletins, PW4ENG A72-628, Rev. 1, and PW4G-100- A72-80, Rev. 1, as applicable.

Modify 2nd stage ring segments and vane clusters, and install improved 2nd stage high pressure turbine rotating seals in accordance with Pratt and Whitney Service Bulletins PW4ENG 72-636, PW4ENG 72-637, PW4G-10- 72-93, and PW4G-100- 72-94, as applicable.

Incorporation of these modifications and installation of an improved 2nd stage HPT rotating airseal constitutes terminating action for Requirement 1 of this Directive.

Note: FAA AD 98-19-03 also refers.

Compliance: 1. At each occasion the HPT is disassembled after the effective date of this Directive.

Within 6 years after the effective date of this Directive.

This Airworthiness Directive becomes effective on 28 January 1999.

Background: This Directive is prompted by reports of 2nd stage HPT rotating airseal cracking which could result in an uncontained engine failure and damage to an aircraft.

Source text

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

1 AD/PW4000/2 - 2nd Stage HPT Rotating Airseal