AD/AE 3007/6 Amdt 2 High Pressure Turbine Stage 2 Wheels (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AE 3007/6 Amdt 1 and issues the following 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.

Rolls Royce (Allison) Turbine Engines - AE 3007 Series

AD/AE 3007/6 Amdt 2 High Pressure Turbine Stage 2 Wheels 6/2009 TX

Applicability:

Rolls-Royce Corporation (RRC) AE 3007A series turbofan engines with high-pressure turbine (HPT) stage 2 wheels, part numbers (P/Ns) 23065892, 23069116, 23069438, 23069592, 23074462, 23074644, 23075345, 23084520, or 23084781, installed.

Note 1:  These engines are installed on, but not limited to, Empresa Brasileira de Aeronautica S. A. (EMBRAER) EMB-135 and EMB-145 aeroplanes.

Requirement:

1.    Perform an eddy current inspection (ECI) or surface wave ultrasonic test (SWUT) inspection on each affected wheel specified in this AD.  Use paragraphs 2.A. through 2.C.(4) of RRC Alert Service Bulletin (ASB) AE 3007A-A-72-367, Revision 1, dated 7 April 2009, or use paragraphs 2.A through 2.M.(8) of RRC Service Bulletin (SB) AE 3007A-72-368, Revision 1, dated 6 April 2009, to perform the inspections.

HPT stage 2 wheels already inspected and passed using RRC ASB
AE 3007A-A-72-367, Revision 1, or earlier issue; or RRC SB
AE 3007A-72-368, Revision 1, or earlier issue, meet the requirements for the initial inspections specified in Requirement 1 of this AD.

2.    Do not return to service, any HPT stage 2 wheel that was installed in any RRC AE 3007A series engine removed as a result of Requirement 1 of this AD, unless the HPT stage 2 wheel was inspected as specified in RRC ASB
AE 3007A-A-72-367, Revision 1 or RRC SB AE 3007A-72-368, Revision 1.

3.    Remove from service any HPT stage 2 wheel covered by this AD that has accumulated 22,500 Cycles-Since-New (CSN).

4.    Do not install any HPT stage 2 wheel that has 22,500 or more CSN.

Later revisions of the above ASB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-08-51 are considered acceptable for compliance with the equivalent Requirements of this AD.

Note 2:  FAA Emergency AD 2009-08-51 dated 10 April 2009 refers.  This AD supersedes FAA AD 2008-26-06.

Compliance:

For Requirement 1 - As detailed in Table 1 of this AD.

Table 1 - Compliance Times for ECI or SWUT Inspection
of the HPT Stage 2 Wheels by CSN

For HPT stage 2 wheels with CSN on the effective date of this AD:	Remove or inspect:
17,500 or more	Before the next flight.
15,560 to 17,499	Within 75 cycles-in-service (CIS).
15,000 to 15,559	Within 150 CIS.
14,700 to 14,999	Within 200 CIS.
14,000 to 14,699	Within 250 CIS.
13,580 to 13,999	Within 450 CIS.
12,460 to 13,579	Within 600 CIS.

For Requirements 2, 3 and 4 - After the effective date of this AD.

This Amendment becomes effective on 15 April 2009.

Background:

The original issue of this AD resulted from reports of cracked HPT stage 2 wheels.  The issuing this AD was intended to detect cracks in the HPT stage 2 wheel, which could result in a possible uncontained failure of the HPT stage 2 wheel and damage to the aeroplane.

The original issue of this AD required performing initial and repetitive ECIs on the HPT stage 2 wheel for cracks.  This AD continues to require those same inspections, but revises the compliance schedule for the initial inspection and specifies the affected HPT stage 2 wheels by part number.

Amendment 2 of this AD results from additional reports of cracks in the HPT stage 2 wheels identified from the required inspections.  A revised risk assessment that includes these additional reports indicates we need to require a higher inspection rate.  This emergency AD also addresses a group of low utilization engines above 16,350 CSN that might not yet have been inspected.  This condition, if not corrected, could result in a possible uncontained failure of the HPT stage 2 wheel and damage to the aeroplane.

The original issue of this AD became effective on 12 September 2008.

Amendment 1 of this AD became effective on 12 March 2009.

James Coyne
Delegate of the Civil Aviation Safety Authority

14 April 2009