Airworthiness Directives; Hartzell Propeller Inc. Model HD-E6C-3B/E13890K Propellers

This amendment adopts a new airworthiness directive (AD), that is applicable to Hartzell Propeller Inc. model HD-E6C-3B/E13890K propellers with certain serial numbers of model D-1199-2 propeller control units (PCU's) installed. This amendment requires initial and repetitive inspections for below-limit propeller flight idle blade angles, and, as a terminating action, removal of the affected PCU's from service and performance of a complete Major Periodic Inspection (overhaul) when the applicable time-since-new or time-since-overhaul limit is reached, or when any flight idle blade angle is below limits. This amendment is prompted by a review by Hartzell Propeller Inc. of the model D-1199-2 PCU overhaul procedures, that revealed several dimensional checks and a nondestructive evaluation were not performed on certain serial number PCU's during a Major Periodic Inspection (overhaul). The overhaul procedures are required to comply with the Airworthiness Limitation PCU Major Periodic Inspection (overhaul) directive. The actions specified by this AD are intended to prevent below-limit flight idle propeller blade angles that, if not corrected, could result in degraded aircraft performance and control.