Airworthiness Directives; Hartzell Propeller Inc., Model HD-E6C-3( ) Propellers

This amendment adopts a new airworthiness directive (AD) that is applicable to Hartzell Propeller Inc. model HD-E6C-3( ) propellers. This action requires replacement of the current design propeller blade thrust bearing with a new design propeller blade thrust bearing and visual and eddy current inspection (ECI) of propeller hubs for cracks. This amendment is prompted by reports of fractured thrust bearings observed during disassembly, one or more blades becoming jammed in position during operation, pitch change fork fractures causing loss of blade pitch control, and excessive vibration. The actions specified in this AD are intended to prevent loss of aircraft control due to loss of blade pitch control, inability to fully feather the propeller, hub fracture, and blade release.