Ad/PW4000/13 - Fan Blade (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.

Pratt and Whitney Turbine Engines - PW4000 Series

AD/PW4000/13 Fan Blade 10/2009

Applicability:

Pratt & Whitney (PW) PW4164 and PW4168 series turbofan engines installed on but not limited to Airbus Industrie A330 series aircraft.

Requirement:

Install a new or a modified fan blade assembly, in accordance with the requirements of PW SB No. PW4G-100-72-92, dated 24 April 1997.

Note:  FAA AD 97-11-06 Amdt 39-10035 dated 11 June 1997 refers.

Compliance:

Within 30 days after the effective date of this AD, unless previously accomplished.

This Airworthiness Directive becomes effective on 24 September 2009.

Background:

The Federal Aviation Administration (FAA) received a report of a high level of N1 rotor imbalance on a Pratt & Whitney (PW) PW4164/PW4168 series turbofan engine during a fan blade out test.  The high N1 rotor imbalance resulted from the loss of several fan blades after fan blade, Part Number (P/N) 55A221, was intentionally released for test purposes.  This high imbalance of the N1 rotor also caused liberation of the fan blade containment system and loss of structural support to the engine inlet cowl.  In revenue service, failure of the fan blade near the root attachment could be caused by metal fatigue.  This condition, if not corrected, could result in fan blade failure and separation at the root section, which could result in high N1 rotor imbalance, and liberation of the fan containment system, which can hazard the aircraft.

James Coyne
Delegate of the Civil Aviation Safety Authority

12 August 2009