Commonwealth legislation

AD/TFE 731/22 - Low Pressure Turbine Third Stage Disc Material Anomalies

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Commonwealth

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legislative instrument

Plain English Summary

4/10 complexity

This directive requires owners/operators of Garrett TFE731-2 and -3 series engines fitted with certain low-pressure turbine third-stage discs (specific part and serial numbers listed in the Allied‑Signal alert service bulletin) to follow that bulletin's removal and replacement procedures because oxide inclusions in a manufacturing heat lot have caused cracking. Compliance is required at the next access to the turbine rotor assembly or within 50 hours after 25 January 1993; operators bear inspection, removal and replacement costs and must schedule maintenance accordingly.

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AD/TFE 731/22 - Low Pressure Turbine Third Stage Disc Material Anomalies

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series

AD/TFE731/22 Low Pressure Turbine Third Stage

Disc Material Anomalies

3/93 DM

Applicability: Garrett Engine Models TFE731-2, -3,-3A,-3AR and -3R equipped with Part Number 3072068-X, 3072544-X, 3073015-X, or 3073115-X low pressure turbine rotor discs identified by the serial numbers listed in the Allied-Signal Aerospace Company Garrett Engine Division Alert Service Bulletin TFE731-A72-3474 dated 3 April 1992.

Requirement: Action in accordance with the requirements of the Allied-Signal Aerospace Company Garrett Engine Division Alert Service Bulletin TFE731-A72-3474 dated 3 April 1992.

Note: FAA AD 92-21-06 refers.

Compliance: At the next access to the turbine rotor assembly or before accumulating 50 hours time in service after 25 January 1993.

Background: Investigation into a turbine hub and disc failure in an Auxiliary Power Unit revealed random oxide inclusions in a heat lot from which a number of Low Pressure Turbine discs for TFE731-2 and -3 series engines was manufactured. An examination of some rotor discs manufactured from this heat lot material revealed that these anomalies had caused cracking in a significant number of them which could could lead to uncontained engine failure. The requirement document service bulletin identifies items made from the heat lot by serial number, and it gives procedures for their removal and replacement.

Source text

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

1 AD/TFE 731/22 - Low Pressure Turbine Third Stage Disc Material Anomalies