Commonwealth legislation

AD/JT8D/37 - HP Compressor Disc Replacement

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

5/10 complexity

This directive requires operators to remove from service certain stage 7–14 high‑pressure compressor discs on Pratt & Whitney JT8D‑1 through ‑17R engines when the disc serial number appears in Appendix 1 of FAA AD 99‑01‑08. It took effect 12 August 1999. The action responds to an uncontained disc failure traced to cadmium embrittlement from a nickel‑cadmium plating process anomaly; operators must follow the FAA AD compliance schedule. Owners pay replacement and traceability costs; the regulator enforces removal unless a disc has already exceeded an established safe threshold.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/JT8D/37 - HP Compressor Disc Replacement.

AD/JT8D/37 - HP Compressor Disc Replacement

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
Pratt and Whitney Turbine Engines - JT8D Series

AD/JT8D/37 HP Compressor Disc Replacement 8/99

Applicability: All JT8D-1 through -17R series engines incorporating a high pressure compressor disc listed by serial number in Appendix 1 of FAA AD 99-01-08.

Requirement: Remove from service stage 7 through stage 14 high pressure compressor discs as specified by serial number in Appendix 1 of FAA AD 99-01-08.

Note: A review carried out when this problem first became known showed that none of the affected discs were installed in engines fitted to Australian aircraft.

Compliance: Unless previously accomplished, as detailed in FAA AD 99-01-08, Compliance (a).

This Airworthiness Directive becomes effective on 12 August 1999.

Background: This directive is prompted by advice of an uncontained HPC disc failure on a JT8D-9 engine. The investigation into this incident identified the disc failure was caused by cadmium embrittlement due to a process anomaly during nickel cadmium plating.

Nickel cadmium plating is used to provide corrosion protection for the disc.

The FAA has advised that several hundred high pressure compressor discs fitted to P&W JT3D and JT8D engines may have been incorrectly processed during nickel cadmium plating at a particular repair facility. Given the potential for further uncontained failures, replacement of the suspect discs has been made mandatory unless they have operated beyond an established safe threshold.

Source text

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

1 AD/JT8D/37 - HP Compressor Disc Replacement