Airworthiness Directives; Hartzell Propeller Inc. Models HC-92WK- ( ) and HC-92ZK-( ) Propellers

This amendment supersedes airworthiness directive (AD) 73-02- 01, applicable to Hartzell Propeller Inc. Models HC-92WK-( ) and HC- 92ZK-( ) propellers, that currently requires visual and penetrant inspections of the propeller blade shank area for corrosion at 1,000 hour time in service (TIS) intervals and shotpeening after inspection. This amendment requires a one-time inspection of the blade clamp screws, then a dye penetrant inspection, compressive rolling of the blade shank, and replacement of blade clamp screws, all to be accomplished at intervals of 500 hours TIS. This amendment is prompted by reports of two recent propeller blade separations that occurred at less than 1,000 hours TIS since last inspection. The actions specified by this AD are intended to prevent propeller blade separation, which could result in loss of control of the aircraft.