Summary
We propose to supersede airworthiness directive (AD) 2006-23- 17, which applies to certain Turbomeca S.A. Turmo IV A and IV C turboshaft engines. AD 2006-23-17 currently requires repetitive inspections of the centrifugal compressor intake wheel (inducer) blades for cracks and corrosion, replacement of parts that fail inspection, and replacement of the TU 197 standard centrifugal compressor. This proposed AD would require the same inspections but at revised intervals, add the replacement of the TU 215 standard centrifugal compressor, and require replacement of parts that fail inspection. We are proposing this AD to prevent failure of the centrifugal compressor inducer, which could lead to an uncontained blade release, damage to the engine, and damage to the airplane.