Airworthiness Directives; Turbomeca S.A. Turboshaft Engines

We propose to supersede airworthiness directive (AD) 2010-11- 10 that applies to all Turbomeca S.A., Astazou XIV B and XIV H turboshaft engines. AD 2010-11-10 requires inspection of certain third stage turbine wheels and removal of any damaged wheel. This AD was prompted by a report of a third stage turbine wheel crack detected during engine overhaul. This proposed AD would expand the population and frequency of repetitive inspections. We are proposing this AD to prevent uncontained failure of the third stage turbine wheel, which could result in damage to the engine and damage to the helicopter.