AD/ALF/21 - High Pressure Compressor Discs (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.

AlliedSignal (Lycoming) Turbine Engines - ALF502 and LF507 Series AD/ALF/21 High Pressure Compressor Discs 6/2009

Applicability: Honeywell International Inc. ALF502L-2 and ALF502L-2C turbofan engines with high pressure compressor (HPC) first stage discs, part numbers (P/Ns) 2-101-331-03, 2-101-331-04, and 2-101-331-10, installed.

Note 1: These engines are installed on, but not limited to, Bombardier CL-600-1A11 aeroplanes. Requirement: 1. For discs with 5,000 or more cycles-since-new on the effective date of this AD, perform a dimensional inspection of the HPC first stage disc to determine if excessive disc balance material was removed. See the following Figure 1 for limits. Limits for Removed Balance Material, Disc Forward Flange Figure 1 (Sheet 1 of 2)

Limits for Removed Balance Material, Disc Forward Flange Figure 1 (Sheet 2 of 2) 2. Replace the disc if excessive disc balance material was removed. See limits in Figure 1 of this AD.

3. If the removed balance material condition is acceptable, perform a magnetic particle inspection of the disc rim and slots for cracks using a 3 to 7 power magnification glass. The Engine Overhaul Manual, 72-34-11, Inspection/Check, contains information on the magnetic particle inspection procedure.