AD/A330/88 Intermediate Pressure Turbine Overspeed Protection (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Airbus Industrie A330 Series Aeroplanes

AD/A330/88 Intermediate Pressure Turbine
Overspeed Protection 9/2008

Applicability:	A330-243, -341, -342 and -343 models, all manufacturing serial numbers (MSN) except those on which Airbus modification 56722 has been embodied during production or Airbus Service Bulletin (SB) A330-73-3049 dated 14 November 2007 has been embodied whilst in service.
Note 1:  This Directive is not applicable to the following A330 aircraft fitted with Rolls Royce (RR) Trent 700 engines and not equipped with Multi Mode Receiver (MMR):
0012 0017 0071 0083	0098 0099 0102 0106	0109 0111 0113 0118	0121 0132 0138 0140	0144 0148 0153 0155	0165 0177 0244
Requirement:	Perform a reprogramming of Data Entry Plug (DEP) on both engines to activate Intermediate Pressure Turbine Over Speed (IPTOS) protection function in accordance with instructions of SB A330-73-3049 or later revision approved by the European Aviation Safety Agency.
Note 2:  The accomplishment of SB A330-73-3049 instructions has an operational consequence.  Consequently, the operator must contact Airbus to get associated operational documentation.
Note 3:  EASA AD 2008-0101 refers.
Compliance:	No later than 30 June 2009.
This Airworthiness Directive becomes effective on 28 August 2008.
Background:	An operator of an A330 aircraft fitted with RR Trent 772 B engines experienced an engine#1 uncontained multiple turbine blade failure.  Investigations have shown that High Pressure/Intermediate Pressure (HP/IP) oil vent tubes are prone to be affected by carbon deposit or to be damaged by their outer heat shields leading to a fire inside or outside the vent tube and resulting into IP Turbine (IPT) disc drive arm fracture and thus IPT disc over speed.

If not corrected, IPT disc over speed could lead to an uncontained engine failure i.e. multiple turbine blade failure or HP/IP turbine disc burst, which would constitute an unsafe condition.

In order to protect IPT from over speed, this Directive requires the activation of the IPTOS protection function by DEP reprogramming, which consists in limiting the IPT speed (Engine Thrust) when overheat is detected in IPT, for all A330 aircraft fitted with RR Trent 700 engines and equipped with Multi Mode Receiver.

James Coyne
Delegate of the Civil Aviation Safety Authority

16 July 2008