AD/CT7/9 - Compressor Variable Geometry Schedule (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 39.1 (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.

General Electric Turbine Engines - CT7 Series

AD/CT7/9 Compressor Variable Geometry Schedule 6/2003 TX

Applicability: All CT7-9B engines.

Note 1: These engines are known to be installed on but not limited to SAAB Aircraft 340B aeroplanes.

Requirement: 1. Determine the Variable Geometry (VG) rigging schedule for both engines. If the compressor VGs are rigged to VG schedule N using GEAE Service Bulletin (SB) CT7-TP S/B 72-0328 or GEAE Alert Service Bulletin (ASB) CT7-TP S/B 72- A0328 Revision 1 no further action is required.

Note 2: The engines with Serial Numbers (S/Ns) listed in Table 1 of this directive are known to have been rigged to VG schedule N1.

2. If the compressor VGs on both engines on the aeroplane are rigged to VG schedule N1, accomplish the following:

1. rig the compressor VG on one engine to VG schedule N in accordance with 3.A.(1) through 3.A.(12) of the Accomplishment instructions of GEAE ASB No. CT7-TP S/B 72-A0328 Revision 1; and

2. rig the compressor VG on the remaining engine to VG schedule N in accordance with 3.A.(1) through 3.A.(12) of the Accomplishment instructions of GEAE ASB No. CT7-TP S/B 72-A0328 Revision 1.