AD/FJ44/1 - High Pressure Turbine Disc (Cth)

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

Williams-Rolls Turbine Engines - FJ44 Series

AD/FJ44/1 High Pressure Turbine Disc 5/97

Applicability: FJ44-1A engines as detailed by serial number in Williams-Rolls Service Bulletin (SB) Number FJ44-A72-30 and not incorporating a part number (P/N) 55291 high pressure turbine disc.

Requirement: To prevent a possible high pressure turbine (HPT) disc blade retention post separation and the release of turbine blades event, carry out an initial and repetitive eddy current inspection of the P/N 48629 HPT disc in accordance with the requirements of Williams-Rolls SB No. FJ44-A72-30.

Note 1: FAA Airworthiness Directive 97-01-05 refers.

Note 2: Compliance with Williams-Rolls SB No. FJ44-A72-31 constitutes a terminating action for the requirements of this directive.

Compliance: As detailed in the requirement document with a revised effective date of 24 April 1997.

This Airworthiness Directive becomes effective on 24 April 1997.

Background: This directive has been issued to require the inspection of certain HPT discs for evidence of cracking in the blade retention posts. The requirement reflects advice of two in-flight HPT disc blade post separation events involving the Williams-Rolls FJ44 engine. One of the events was uncontained. An investigation of the events revealed in both cases, the HPT blade retention posts separated through cracking caused by material creep/fatigue.